Vol.5 ,No.1, April 2018

Transactions on

GIGAKUSpecial issue of
The 6th International GIGAKU
Conference in Nagaoka(IGCN), 2017

GIGAKU Press
Nagaoka University of Technology

Transactions on GIGAKU: Scope and Policy
Nagaoka University of Technology publishes an online, open access journal titled “Transactions on
GIGAKU”, which is focused on the science and technology related to GIGAKU*. The mission of thisjournal is to spread out the concept of GIGAKU and the fruits of GIGAKU to the global world and to
be a strong network for innovations in science and technology and for development of next
generations of high-level human resources. This journal, therefore, covers research and education
activities related to GIGAKU in broad areas.
*

See ‘What is GIGAKU?’ below.

‘What is GIGAKU?’GIGAKU is a term composed of two Japanese word-roots; GI and GAKU. The word GI〔技〕
literally stands for all kinds of arts and technology, and GAKU〔学〕 stands for scientificdisciplines in general when used as a suffix.
The term was originally coined to describe the fundamental philosophy of education and research of
Nagaoka University of Technology (NUT) when it was established in 1976. Through this term thefounders of NUT intended to express their recognition that all technical challenges in the real world
require a scientific approach. And NUT has a relentlessly pursued GIGAKU since then.
Fourty-one years have passed and all surrounding conditions have changed dramatically during those
years. We are witnessing rapidly globalizing economics and huge scale changes in demographic,
industrial and employment structures. All those changes seem to necessitate the further evolution of
GIGAKU. In response to this, NUT recently announced its new “Growth Plan” and a reneweddefinition of the term is given;
GIGAKU is a science of technologies, which gives us an angle to analyze and reinterpret diverse
technical processes and objects and thus helps us to advance technologies forward. By employing abroad range of knowledge about science and engineering, management, safety, information
technology and life sciences, GIGAKU provides us with workable solution and induces future
innovations.

October 2017
Nobuhiko Azuma,President of Nagaoka University of Technology

1Editors (2017 to 2018):
Editor-in-chief:
Dr. Masato Aketagawa, Professor, Department of Mechanical Engineering, Nagaoka
University of Technology (NUT), Japan
Co-Editors:
Dr. Kazunori Sato, Vice President, NUT
Dr. Shigeru Nagasawa, Professor, Department of Mechanical Engineering, NUT
Dr. Tsutomu Takahashi, Professor, Department of Mechanical Engineering, NUT
Dr. Yukio Miyashita Associate Professor, Department of Mechanical Engineering,
NUT
Dr. Tomoichiro Okamoto, Associate Professor, Department of Electrical, Electronics
and Information Engineering, NUT
Dr. Tsuneo Suzuki, Associate Professor, Department of Nuclear System Safety
Engineering, NUT
Dr. Takaomi Kobayashi, Professor, Department of Science of Technology Innovation,
NUT
Dr. Takashi Yamaguchi, Professor, Department of Science of Technology Innovation,
NUT
Dr. Takashi Yukawa, Professor, Department of Science of Technology Innovation,
NUT
Dr. Tadachika Nakayama, Professor, Department of Science of Technology Innovation,
NUT
Dr. Yuichi Otsuka, Associate Professor, Department of System Safety, NUT
Dr. Makoto Ichitsubo, Professor, Department of General Education, NUT
Submission and Publishing“Transactions on GIGAKU” publishes original papers focusing on education, science,and technology related to GIGAKU. Papers submitted are peer-reviewed before
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Transactions on GIGAKU
Volume 5, No. 1, April 2018
The 6th International GIGAKU Conference in Nagaoka (IGCN)(October 5-6, 2017, Nagaoka University of Technology, Nagaoka, Japan)
The IGCN is designed and organized to provide a cross-border, cross-sector,
cross-disciplinary forum for those researchers, educators, and industrial leaders who are
creating and practicing GIGAKU in various technology domains in various countries.
Some papers presented in the IGCN are published in this first volume of Transactions
on GIGAKU.
Table of contents
1. Pages 05001/1-6
Operation of Engineering Design Educational Program Covering
Environmental Problems in Local Community
Tsukasa Sato, Michiaki Shishido, Takeshi Houga, Ryoji Onodera
2. Pages 05002/1-9
Training of Practical and Creative Nuclear Engineers
Using Unsealed Radioisotopes
Yu Tachibana, Tatsuya Suzuki
3. Pages 05003/1-7
Folding Characteristics of Multiple-Scored Portion of Corrugated Fiberboard
Haruya Yokoyama, Shigeru Nagasawa
4. Pages 05004/1-8
Preparation and Characterization of Cellulose Hydrogel Films from
Myanmar Thanaka Heartwood
Cho Cho, Takaomi Kobayashi
5. Pages 05005/1-6
Palladium Ion Adsorbent of Fibrous Silk Fibroin Prepared from
Silkworm, Bombyx Mori
Tsukasa Sato, Tsugumi Seki, Saki Abe, Shinko Ito, Tatsuo Abe
6. Pages 05006/1-8
Numerical Study on Controlling Factors ofConvection Behavior of Hydrogen Generated inRadioactive Waste Long-term Storage Containers
Yusei Tanaka, Kazuyuki Takase

3

Transactions on GIGAKU 5(1)(2018)05001/1-6

Operation of Engineering Design Educational Program Covering
Environmental Problems in Local Community
Tsukasa Sato*, Michiaki Shishido, Takeshi Houga, Ryoji Onodera
Department of Creative Engineering, National Institute of Technology, Tsuruoka College,
104 Sawada, Inooka, Tsuruoka 997-8511, Japan*E-mail: tsato@tsuruoka-nct.ac.jp

In order to train engineering design ability for the students in advanced course
in Tsuruoka college, the unique program has been developed and operated.
This program includes three policies; 1) cooperation with the local community
type education, 2) grouping by mixing different subject-of-study, 3) training
camp activities at off-campus area. Themes were proposed by teachers. For
example “development of beach cleaning equipment”, “producing naturel salt
from sea water and its application”, and so on. According to the student's
self-evaluation, the student was aware of improvement by lesson.
However, the difference of the results arose by the group. We felt
the necessity for suitable theme which raises a student's motivation.

1. Introduction
The industrial technical society has been highly developed and complicated in recent years. In
order to correspond to such trends, the educational curriculum “engineering design” has been
extended in technical college rapidly. In the engineering design the students learn how to make theobjects or propose systems fulfilling social needs by combining various knowledges and technologies[1]. The social needs or problems do not necessarily have a correct one answer, and they must findout the practical solutions. The engineering design program educates the students to have creativity,
integration of various knowledge, communication skills, and teamwork ability, and so on. From2012 in Tsuruoka college, the new subject named "practical design engineering exercise" has been
operated for the students in 1st year of advanced course. This paper reports practice of theengineering design education on the theme of the environmental problem of remote island“Tobishima” of Yamagata Prefecture. This paper also discusses the some problems found in the
program operated. The program includes unique three policies; 1) Cooperation with local
community, 2) Grouping by mixing different subject-of-study, 3) Training camp activities at
Tobishima [2, 3].
2. Proposed Program

In order to carry out the engineering design education program effectively, unique three policies
are introduced in the program, which are described as follows:
1) Cooperation with local community; Students recognizes clearly the problems peculiar to the local
area, and make effort to draw solutions from various view of points. In the program we tackled thesubject in connection with the environmental problems in Tobishima island. The meeting was held
between the staffs of the college and local government before the program. And the suitable plan
was constructed.
2) Grouping by mixing different subject-of-study; The group comprised of students was composedby mixing of different subject-of-study, i. e., departments of mechanical engineering, electrical andelectronic engineering, control and information systems engineering, and chemical and biologicalengineering(Fig. 2). The purpose of such grouping is that the students tackle the problems fromvarious aspects. Members of groups were decided by the teachers.

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Transactions on GIGAKU 5(1)(2018)05001/1-6ab

Figure 1 Scenes of cooperation with local community; (a) meeting with local resident, (b) lecture aboutproblems in local community.

Advanced courseGrouping by mixing
different subject

2nd
１st

5th

Group1

4th

Group23rd
2ndGroup3

1st
MechanicalEngineering

Figure 2

ElectricalandElectronic
Engineering

Control andInformation
Systems
Engineering

Material andBiologicalEngineering

Theme setting
by teachers

Group4

Concept of grouping by mixing different subject, and setting theme.

3) Training camp activities at off-campus area; Training camp at Tobishima was carried out for the
students to understand the importance of collaboration and the responsibility of the individual ingroups. As other purpose, the students can concentrate on activity all day. During training camp,lecture meeting by invited visiting lecturer were also held, in order to gain useful knowledge to thestudents.
baFigure 3 Scenes of training camp activities at Tobishima island;(a) group working in the school gym, (b) cooking at kitchen.

The operation time of this program consists of 90hours (school hours) and is equivalent to twocredits. The time arrangement for this program is shown in Table I [4, 5]. The group division andtheme setting were at the 1st time of the term, which were carried out in 1) preliminary investigationin Table I. The training camp was held twice in that turn. The 1st camp was performed for the
purpose of inspection and of understanding of Tobishima Island, which was held for two days at from2

Transactions on GIGAKU 5(1)(2018)05001/1-6

Fri., May 27 to Sat., May 28 in 2016. It should be noted that the 1st camp should be carried out earlytime as well as possible for the purpose of the camp. However, on account of the schedule of a school
events and teaching staffs, the camp time was carried out as above. In the 2nd camp, the field trial of
the products of manufacturing was conducted. It carried out for 4days at from July 22 (Fri.) toFebruary 25 (Mon.) in 2016.
The scholastic evaluation for students was judged by the following aspects and score distribution:

1. Evaluation from auditor in presentation............40%
2. Evaluation from the teacher in charge in presentation……... 25%
3. The resulting report after practice............25%
4. Activity in this practice............10%
total 100%

Table I Time arrangement for the program.
Contents
1) preliminary investigation2) camp activity at off-campus

Description
investigation about Tobishimaisland and suitable engineering
technologies
field study, lecture, meeting, etc.

3) group work in campus

continuing manufacturing

4) presentation

proposal about their design or
products
additional activity time5) others
total

Operation turn8hrs

32〜48hrs (4〜6days)
26hrs(2h/weeks×13weeks)
8hours
0〜6 hrs90hrs

3. Practice of Program
Tobishima is only one of remote manned island in Yamagata Prefecture. The area of an island
measures 2.7km2. Population is about 200 persons. An elderly ratio is about 67%. Although theindustries are fishing and sightseeing, the industries should be more activated for sustaining the livingin the island. From the meeting between the teaching staff and the local government decided as main
theme relevant to problems of environmental issues. Beach waste is washed up on the seaside,
generating of the horse fly which troubles a tourist, needs sightseeing guidance tool for tourist, and soon. Then, the teachers decided to carry out about four themes as listed in Table II. The numberof students was twenty persons in all. Since the student was divided into four groups,
the number of students of each group was five persons.
Table II
group
group 1group 2group 3group 4

Themes of activity for each groups.
theme

Development of beach cleaning equipment
Producing naturel salt from sea water and its application
Making the three-dimensional model of Tobishima island with 3D printer.
Collecting equipment of a noxious insect (horse fly)

The site of training camp was kindly offered from city staff to use the gymnasium of elementary andjunior high schools in island. Since public transport in the island was poor, the school car was3Transactions on GIGAKU 5(1)(2018)05001/1-6

brought and used for convenience. Meal was prepared by themselves borrowing the kitchen in theschool.
For example, details of activities of groups 1 and 2 are as follows:group1 At beginning of making the equipment, students researched the commercial one andrecognized that is expensive and large weight. Therefore they turned out that low cost andlightweight equipment would be useful. The students tried to make the equipment by using familiar
materials such as plastic nets and the frame made from aluminum. This equipment consists of eightrotors. Wings are plastic nets. If equipment is pulled, a rotor will move on sand, and sand andgarbage will be picked up together. Sand falls from through a net and the garbage remains. At last
the garbage is brought together in the cave inside the axis of rotation. However, since the sand wastend to condense, separation of garbage and sand was not fully completed. In addition, the rootersleft garbage on sand in many cases. In order for a rotor to collect garbage efficiently, it need to be
improved on structure of the rotor.

Figure 4

Test run of the beach cleaning equipment.

group 2 On the producing naturel salt from sea water, it was found out that the concentration ofmagnesium of the sea water around Tobishima was high compared with other ocean
space as a result of quantitative analysis of minerals. Taking advantage of thischaracteristic, they thought of the application as bittern. Bittern is an additive used
when making tofu. The students studied making tofu by themselves, and completed.
In the beginning stage, tofu did not become hard and their failure continued. At last,using the condensed sea water, they completed by carrying out with the optimal
temperature of soy milk.
From the quanitative analysis the sea
water at Tobishima has rich in Mg(mineral).

Figure 5

Process of making tofu using
soybean and condensed sea waterof Tobishima.

Excerpt a part from student's (group 2) presentation data.

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The proposal for the citizens about results obtained from this activity was held at“Environmental fair in Tsuruoka 2016” as large environmental event in the city held on
September 25, 2016 in the city gymnasium. Students presented using the poster andexhibiting the manufacture products.
After the practice of the program in Tobishima island, the questionnaires to thestudents were conducted in order to investigate the improvement of a student's
consciousness. The self-evaluation, how are the degree of achievement for students in
his own consciousness and capability at before and after the program were conducted.

Figure 7

Proposal towards citizens in “Environmental fair in Tsuruoka 2016”

Question items were 1 team work, 2 sence of ethics, 3 problem solving systematically, 4communication, 5 sincerity, 6 cooperativeness, 7 leadership, 8 special capability, 9 activity and 10
creativity. Each of items were evaluated by marking numbers from 1(weak) to 5(strong), and allscores were averaged (Fig. 8). The questionnaire survey was conducted to all the students, after thatthe data was divided into each group and was averaged by the group number (five persons).

Figure 8

Results of self-analysis by students before and after the program

As shown in the figure, it seems that the students themselves realized the progress in the all items,
especially in motivation to the activity, contribution to local community, and cooperation andcommunication in group. However, the difference in a result became clear between groups. The
improvement has been weaken in the group 1. Typical students’ comments are listed Tab. III.

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Table III Students’ comments (group 1 and 2) after the program
group
Group1

Group2student's comments
I was not unsatisfactory with the theme
There was an uncooperative student.
I felt inconvenience at training camp activities at Tobishima island.
Everybody was cooperative.
The theme was attractive.

The final report of the students in group 1 told that there was an uncooperative student in their group.
The student was unsatisfactory with the theme because the theme does not meet a special field of study.
Since the students in this case have been familiar with convenient social life, probably they want toavoid inconvenience and difficulties. On the other hand, the group 2 had the highest result of selfvaluation of all the groups. The reasons were the theme was attractive and the member werecooperative. Thus, for group activity the cooperativeness of students and attractiveness of a themeis important. Moreover, an understanding for students of the importance of combining of a subjectof-study is also crucial. In these activities, teachers at first construct four groups arbitrarily. And
then themes and detailed directions were given to the each group from the teachers. However, thesuitable theme might not be given for some students. It would become unsatisfactory for the students.
The following improvements should be planned from now on. For example, at first teachers show
some themes toward students, and then the students can choose the subject which got interested.
However, combination of a subject-of-study must be maintained. Such improvements have been
introduced in activity in 2017. The students are working very enthusiastically till the present, andthe completeness of a products are high. The results will be reported next time.

4. Conclusion
The engineering design education based on the environmental problem at remote island“Tobishima” of Yamagata Prefecture was carried out in 2016. The working group wascomposed by the students who consists of different subject-of-study combination. The theme
made by the teacher presented to the groups. Throughout training camp activities inTobishima, the students learned importance of engineering design activity. According to thestudent's self-evaluation, the student was aware of improvement by lesson. However, thedifference of the results arose by the group. We felt the necessity for suitable theme whichraises a student's motivation. .

Acknowledgments
This work was supported by JSPS KAKENHI Grant Number JP16K04799.
References[1] I. Oonaka, “Correspondence to the engineering design education in JABEE; Basic Policy”
http://www.jabee.org/news_archive/news2009/20090318-2/2356.
[2] T. Sato, M. Shishido, T. Houga, and R. Onodera, “Practice of Community Contribution TypeEngineering Design Education with Training Camp Activity”, kōsen kyōiku, vol. 37, 441, 2014.
[3] M. Shishido, T. Sato, T. Houga, and H. Motohashi, “Engineering Design Education Assigned
Energy Saving and Disaster Prevention Measures of the Remote Island”, Japan Society for Design
Engineering, 50, 389, 2015.
[4] M. Shishido, T. Sato, T. Sato, T. Sato, T. Houga, and R. Onodera, “Framework Construction ofRegional Cooperative Off-campus Curriculum Studies”, Transactions of ISATE 2015, The 9thInternational Symposium on Advances in Technology Education, 429, 2015.
[5]Tsukasa Sato, Michiaki Shishido, Takeshi Houga, and Ryoji Onodera, “Development ofEngineering Design Educational Program Cooperation with Local Community” Transactions on
GIGAKU, vol. 3, no. 2, 03006/1-8, 2016.
(Received: 12 October 2017, Accepted: 2 February 2018)6

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Training of Practical and Creative Nuclear Engineers
Using Unsealed Radioisotopes
Yu Tachibana*, Tatsuya Suzuki
Department of Nuclear System Safety Engineering, Graduate School of Engineering,
Nagaoka University of Technology,1603-1 Kamitomioka-machi, Nagaoka 940-2188, Japan*E-mail: yu_tachibana@vos.nagaokaut.ac.jp

We have successfully developed one of the novel curriculum to train practicaland creative nuclear engineers, combined systematically with the Act on
Prevention of Radiation Hazards due to Radioisotopes, etc. which is one of thelaw in Japan and the handling of unsealed radioisotopes. These key points
updated for our department’s laboratory experiment have been introduced. We
have also conducted the laboratory experiment to confirm whether the revised
contents work well or not. Concretly, we have practically tested the wellknown methods for surface contamination inspection in the controlled area
before and after laboratory experiment. The two types of inspections classified
as survey and smear methods were used in the experiment. It was evident thatthe experiment rooms and appatatuses had no traces of contamination. In
addition, the experiments for nuclide separation and identification of nuclides
were also carried out in the methanolic nitric acid solution. We also confirmed
to separate mutually many metal ions by using anion-exchange
chromatographic technique because a little difference among the individual
peak positions in the chromatograms has been observed clearly. Also, the yieldand distribution coefficients obtained from ICP-MS measurements ofEuropium (Eu) element were identical to those of Germanium (Ge)-detector
measurements. Based on these results, we have finally confirmed that our
proposing contents are suitable for the prospective students to be practical andcreative nuclear engineers.

1. Introduction
National Institute of Technology (NIT) has produced a large number of practical and creativeengineers to support Japanese industries. As well as engineers graduated from universities, engineers
graduated from NIT are actively involved at the forefront of various sections such as research anddevelopment, production management, manufacturing technology, etc.. In the industrial world, they
are highly regarded as an engineer. Recently, they have tried to learn advanced technology and more
profound knowledge. Hence, it has become natural for them to go to university. The nuclear industry
has also been dramatically developed by their great efforts. Although the education in nuclear
technology has been already carried out there, NIT does not have the department related to nuclear
technology. In addition, there are few controlled laboratories which can handle radioisotopes in NIT.
Nagaoka University of Technology has performed the original education and research activities incooperation with NIT. The department of Nuclear System Safety Engineering has also educated many
students graduated from NIT, by conducting many lectures for them. However, the knowledge andexperience for handling unsealed radioisotopes have been still insufficient. We must surely trainengineers with more practical and creative nuclear abilities. It is important for them to learn theunsealed radioisotope handling technologies and radiation measurement technologies. Therefore, wehave been carrying out the chemical separation experiments using unsealed radioisotope as a part ofthe laboratory experiment in our department since 2015. However, our previous curriculum did notrefer to much practical knowledge and methods to keep the radiation controlled area safe, i.e., thiscurriculum does not mention clearly how to do the surface contamination inspection before and after1

Transactions on GIGAKU 5(1)(2018)05002/1-9

laboratory experiment, how to take out unsealed radioisotopes from storehouses for radioisotopes, andhow to keep them temporarily in storehouses for spent radioisotopes as typical examples. Especially,
how to fill out a special document to use radioisotopes, following the Act on Prevention of Radiation
Hazards due to Radioisotopes, etc. should be understood surely. Unfortunately, for overseas student
studying in Japan, our previous textbook was written in Japanese. As a result, it should be modified
with “novel curriculum to train practical and creative nuclear engineers”. In this curriculum, allstudents act a role of first-class Radiation Protection Supervisor at Radioisotope Center, Nagaoka
University of Technology and can systematically learn basic manners and typical operation procedures
using unsealed radioactive sources in the radiation controlled areas, based on the Act on Prevention ofRadiation Hazards due to Radioisotopes, etc. [1]. The recommendation from International
Commission on Radiological Protection, supported by International Atomic Energy Agency,
Organization for Economic Co-operation and Development, Nuclear Energy Agency, International
Radiation Protection Association, etc. is also adopted into the act and the contents are revised one after
another. In addition, they can learn how to separate a simple element from aqueous solutions
containing fission products and how to use leading-edge analyzers for its ultramicroanalysis. There
are no educational institutes which works on our suggested method of guidance. It has been expectedthat most of students including students with a full-time job are satisfied with our very well versed
latest curriculum.
On the basis of these backgrounds, we have developed the novel curriculum to train practical andcreative nuclear engineers, combined systematically with Act on Prevention of Radiation Hazards due
to Radioisotopes, etc. and the handling of unsealed radioisotopes. These key points updated for our
department’s laboratory experiment have been introduced and we have also conducted the novel
laboratory experiment to confirm whether the revised contents work well or not.
2. Concept of Laboratory Experiment2.1. Importance of Surface Contamination Inspection
When students do some experiments using unsealed radioactive sources in radiation controlledareas, students must definitely carry out surface contamination inspection before and after our
department’s laboratory experiment. If students do not carry out the inspection before theirexperiments, students may be exposed to radiation due to the contaminated surroundings. Hence,
students certainly have to perform the inspection and try to minimize their radiation exposure. In
addition, it is necessary for the following handler to carry out the inspections after the completion of
their experiments because they can devote themselves to do their works using unsealed radioactive
sources without any decontamination procedures. The two types of inspections classified as survey
and smear methods are reliable generally. For example, a survey method is to examine some areas
with the possibility of contamination using a handy-type survey meter such as ref. [1]. However,students are not able to utilize a survey meter in surroundings at a high dose rate. For radioactive
nuclides emitting γ-ray and β-ray, students can make use of a Geiger Muller survey meter and a gas
flow proportional counter is useful for the detection of radioisotopes emitting β-ray with comparatively
low energy. Moreover, a survey meter with a scintillation counter or a semiconductor counter iscapable of the detection of α-emitters. On the other hand, the smear method is to wipe some areas withthe possibility of contamination using a smear filter paper and measure the wiped samples using an
automatic measuring apparatus equipped with α-ray and β-ray detectors such as ref. [1]. In case of asmear method, it is generally difficult to completely wipe with radioactive nuclides impregnated onto
the floor. Therefore, students must always carry out both the types of surface contamination inspection
to complement the individual defects before and after the laboratory experiments.
2.2. Summary of Nuclide Separation Experiment Using Anion-Exchange Chromatography andNuclide Analyses Using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) andGamma-ray Spectroscopy with Germanium Detector (Ge-Detector)
2.2.1. Nuclide Separation Using Anion-Exchange Chromatography
In the laboratory experiment, students perform radioactive nuclide separation experiment using
typical anion-exchange reactions. Ion exchange process is classified as cation-exchange and anion
exchange processes indicating an exchange of ions between two electrolytes or between an electrolyte2Transactions on GIGAKU 5(1)(2018)05002/1-9

and a complex in a solution. When metal cations try to adsorb chemically with anion-exchanger, metalanions must be formed via complexation reactions such as the following equilibrium reaction (1). The
existence of a number of ligands for a metal ion depends on its electronic state in solvents. In brief,
many chemical surroundings of anions and complexes are strongly dependent on kinds of elements insolvents. As a result, different adsorption abilities of metal anions for anion-exchangers are expressed
spontaneously. In addition, even if the difference of distribution coefficients per plate is small, it iscomparatively easy to prepare a multistage chromatographic apparatus, i.e., it is possible to separate
mutually many metal ions using anion-exchange chromatographic technique.
Eu3+ + nNO3- ⇄ [Eu(NO3)n]3-n(n ≥ 4)(1)

In a nuclide separation experiment, students use a benzimidazole-type anion-exchange resin
embedded in high-porous silica beads (AR-01 resin). The AR-01 resin which has two types offunctional groups consisted of 1-methylbenzimidazole and 1,3-dimethylbenzimidazole was chosen for
the nuclide separation experiments because the AR-01 resin has much higher resistance to redox
reactions, radiation, and heat, compared with those of other resins [2]. The chemical formula and theSEM images of AR-01 resin (VE-8800, Keyence) are shown in Fig. 1 and 2, respectively. The
quaternization ratio of AR-01 resin is 58.8 % and the diameter of the silica beads is 40-60 μm [3]. The
AR-01 (Cl form) resin was synthesized and supplied from Laboratory for Advanced Nuclear Energy,
Tokyo Institute of Technology, Tokyo, Japan [4]. The equilibrium reaction (2) is available in theexperiment [5].
AR-01+･Cl- + [Eu(NO3)n]3-n ⇄ AR-01+･[Eu(NO3)n]3-n + Cl-(n ≥ 4)

Fig. 1 Structural formula of AR-01 resin

Fig. 2 SEM images of AR-01 resin
3(2)

Transactions on GIGAKU 5(1)(2018)05002/1-9Students use Eu-152 as a radioactive tracer in the experiment. Stable isotopes consisting of Cs, Sr,
Y, Ru, Rh, Sb, Te, Ba, Mn, Co, Eu-151, -153, and Na elements are also used in the experiment. Euelement is classified as lanthanide series which composes the f-block of period 6 in the periodic table
and is also one of typical fission products contained in high-level radioactive wastes [6]. Cs, Sr, Ru,
Rh, Sb, Te, Ba, Mn, and Co elements are mainly contained in the contaminated water from Fukushima
Daiichi Nuclear Power Plant Accident [7]. We use Na species to measure the dead volume of the flow
path of separation apparatus [8]. It has been known that Cs+, Sr2+, Y(III), Ru(IV, VI, VII), Rh(III),
Sb(III, V), Te(II, IV, VI, etc.), Ba2+, Mn2+, Co2+, Eu(III), Na+ exist in aqueous solutions, respectively.
It can be estimated that some metal cations in these species coordinate with one and more nitrate ion
in nitric acid solutions. We have considered that the favorable tendency for the nitrate coordination
will be in order of Na ≤ Mn ≒ Co ≤ Cs ≤ Sr ≒ Ba ≤ Y < Eu. Until now, the reasonable chemical
structures of Y, Ru, Rh, Sb, and Te elements have not been determined in the experimental conditions
which is expected to be clear soon [9]. The permittivity (ε) of water (εwater = 80.1 at 20oC) is higher
than that of alcohols such as methanol (MeOH) (εMethanol = 33.4 at 20oC) [10], i.e., an addition of
sufficient volume of methanol into nitric acid solutions trigger the increase of the coordination numberof metal ions [11]. Therefore, a nitric acid solution containing methanol has been decided to use as amobile phase in the experiment.
2.2.2. Nuclide Analyses Using ICP-MS and Ge-Detector
The qualitative and quantitative analyses of the examined metal ions in the collected samples isperformed by using a ICP-MS analyzer (7700x, Agilent). On the other hand, it has been known that
Eu-152 emits mainly gamma-ray with an energy range between 0.122 and 1.408 MeV [12]. Hence, it
is also possible to identify Eu-152 by using a Ge-Detector (DSPEC jr 2.0, Seiko EG&G). In thisexperiment, students use ICP-MS and Ge-Detector to calculate the concentration of samples collectedfrom chromatographic experiments.
2.2.3. Individual Role
When students carry out some experiments using unsealed radioactive sources in the radiation
controlled area, it is very important for students to decide the individual role in the group. This decision
could decrease many chances of unprecedented radiation exposure. For example, we have suggested
that students should decide the individual role on one as the handler of radioisotopes, two assistantsfor the radioisotope handler, two operators of ICP-MS and Ge-Detector, and one person to record thedata.
3. Validity of Contents
3.1. Surface Contamination Inspection before and after Laboratory Experiment
Before and after the laboratory experiment, we carried out the surface contamination inspection tokeep controlled rooms clean at Radioisotope Center. This inspection was performed by using a handheld Geiger Muller survey meter with a wide mica window (GM) (TGS-146B, Hitachi-Aloka Medical),a handy-type survey meter with a scintillation counter (Scintillation) (TCS-362B, Hitachi-Aloka
Medical), and additionally we inspected the controlled rooms by using a smear method. We used an
automatic measuring apparatus equipped with detectors of α-ray and β-ray (Hitachi-Aloka Medical,
JDC-5300) for samples from the method using a smear filter paper provided from Chiyoda Technol.
Compared with values calculated from blank samples, we confirmed whether the collected samples
were contaminated or not. Each sample had a measurement time of 1.5 minutes. The obtained values
were strictly confirmed to be within 4 Bq/cm2 for α-ray and 40 Bq/cm2 for β-ray [1], following thelaw. When they exceed the maximum values regulated under law, we wiped the entire contaminatedarea with special cleaners as soon as possible.
Table 1 shows the result of surface contamination inspection before and after laboratory
experiment. From the results of GM and Scintillation before laboratory experiment, we found that allvalues are similar to the background value. It was also found that all values before the experiment arealmost the same as those after the experiment. The background value was also not excluded from thesevalues in case of the survey method. Based on the results of the survey method, the results indicatedthat the experiment rooms and apparatuses accompanying them, are not contaminated. On the other4Transactions on GIGAKU 5(1)(2018)05002/1-9

hand, it was impossible to calculate the radioactivity of α-ray and β-ray using an automatic measuringapparatus equipped with detectors of both radiation because of much lower radioactivity of all samples.
Therefore, those results were attributing to no contamination.
Table 1 Evaluation sheet for the result of surface contamination inspection before and after laboratory
experiment
Survey method(GM-type / Scintillation-type)Measurement
points

1. Blank sample

2. Thermostat
apparatus,

Before (cpm)

After (cpm)(75 ± 17) / (GM)(81 ± 18) / (GM)

α(

α(

0

)

0

)

β (183 ± 27)

β (189 ± 28)/ (Scintillation)/ (Scintillation)(77 ± 18) / (GM)(70 ± 17) / (GM)

α(

α(

0

)

0

)

column stand,β (136 ± 23)

β (141 ± 24)

fraction collector/ (Scintillation)/ (Scintillation)(69 ± 17) / (GM)(64 ± 16) / (GM)α(α(

3. plastic vat

4. Laboratory

0

)

0

)

β (148 ± 24)

β (164 ± 26)/ (Scintillation)/ (Scintillation)(77 ± 18) / (GM)(72 ± 17) / (GM)

α(

α(

0

)

0

)

β (187 ± 27)

β (159 ± 25)/ (Scintillation)/ (Scintillation)(60 ± 15) / (GM)(67 ± 16) / (GM)

5. Floor around aα(α(laboratory bench

β (152 ± 25)

β (167 ± 26)/ (Scintillation)/ (Scintillation)(77 ± 17) / (GM)(74 ± 17) / (GM)α(α(benches

6. Laboratory
bench in a fume

0

0

)

)

0

0

)

)

β (166 ± 26)

β (173 ± 26)/ (Scintillation)/ (Scintillation)(71 ± 17) / (GM)

(68 ± 16) / (GM)

7. Floor in frontα(α(of a fume hoodβ (169 ± 26)

β (168 ± 26)/ (Scintillation)/ (Scintillation)

8. Floor and(66 ± 16) / (GM)(67 ± 16) / (GM)bench around a

α(

α(

hood

Ge-detector

0

0

)

)

β (181 ± 27)

0

0

)

Smear method(Scintillation-type)
Before (Bq)

After (Bq)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

)

β (179 ± 27)

5

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9. Floor andbench around a
ICP-MS analyzer
10. Floor andpipes aroundgeneral reservoir
and reservoir for
dilution process<Judgment>(Please markyour decision
with a circle)
ND = not detected.

/ (Scintillation)/ (Scintillation)(72 ± 17) / (GM)(72 ± 17) / (GM)

α(

α(

0

)

0

)

β (191 ± 28)

β (143 ± 24)/ (Scintillation)/ (Scintillation)(70 ± 17) / (GM)(61 ± 16) / (GM)

α(

α(

0

)

0

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

α(

ND

)

α(

ND

)

β(

ND

)

β(

ND

)

β (176 ± 27)

β (165 ± 26)/ (Scintillation)/ (Scintillation)

Contamination

Contamination

Contamination

Contamination

No Contamination

No Contamination

No Contamination

No Contamination

3.2. Experiments for Nuclide Separation and Identification of Nuclides
Following the flowchart, the experiments for nuclide separation and identification of nuclides werecarried out in two kinds of aqueous solutions at our Radioisotope Center.
1) We turned on power to a SJ-1211-type peristaltic pump, a LTCi-150HP-type water circulating pump,
a CHF100AA-type fraction collector. Although their default values ought to be established before, we
checked their condition again. If not, we must manage to set up. The temperature was kept constant at
60oC. Each effluent volume was collected every 1.0 mL.
2) The radioactive nuclide separation apparatus is illustrated in Fig. 3. The above-mentioned AR-01
resin (VR = 1.15 mL (without a volume of high-porous silica beads)) was packed into the column inadvance. For conditioning of this column, we washed a series of flow path by using the ca. 30 mL
methanolic nitric acid solution (1.0 M HNO3 / MeOH = 2 : 8 (vol%) as a mobile phase. Both chemicals
were provided from Nacalai Tesque, Inc.. 1.0 M HNO3 solution was prepared carefully without any
contamination using ultrapure water (Specific electrical resistance: ≥ 18.2 MΩcm, total organiccarbon: ≤ 3 ppb (ppb = ng/g)) produced using a Merck Millipore apparatus (Milli-Q Integral 3 Water
Purification System). We used the previously prepared mobile phase on the plastic vat. “M” and “L”
represent “mol / dm3” and “dm3”. Through this process, the initial form of AR-01 resin was converted
into Cl form. By way of caution, we checked to be adjusted to the 4th dial number on the peristaltic
pump again. This 4th dial number means that the flow velocity is adjusted to 0.50 mL / min.
3) We filled out the form to handle unsealed Eu-152 (Japan Radioisotope Association) and took
carefully the reagent bottle containing unsealed Eu-152 from the storehouse for radioisotopes. We
added Eu-152 adjusted to 50 kBq into 10 mL beaker. 60 wt% HNO3 solution of 1.0 mL with Cs, Sr, Y,
Ru, Rh, Sb, Te, Ba, Mn, Co, Eu, and Na elements (Wako Pure Chemical Industries) were also added
into the same beaker. This initial sample of 1.0 mL contains 50 kBq Eu-152 on June 1, 2017 and twelve
kinds of elements with an approximate concentration of 1.0 mM. By handling an infrared heating anddrying lamp and a digital hotplate kept constant at about 100oC in the fume hood, the foregoing sample
solution was evaporated slowly until completion. Then, we added the dry samples in the fume hood
into the 1.0 mL mixture solution of HNO3 and MeOH (HNO3 : MeOH = 2 : 8 (volume ratio)). The
VS-25-type ultrasonic cleaning machine was used to dissolve the mixture as soon as possible. The
person handling Eu-152 compulsorily wore safety glasses during the experiment.
4) We measured the aforesaid samples using the Ge-Detector. The measurement duration was 3
minutes. The obtained value was used as one of the initial samples.
5) After we numbered sample tubes made of polypropylene with a black marker from 1 to 50, we kept
them carefully in the fraction collector. Parallel to the experimental section from II to IV, this6

Transactions on GIGAKU 5(1)(2018)05002/1-9

preparation was separately carried out to minimize their unnecessary radiation exposure.
6) We turned off the SJ-1211-type peristaltic pump, confirmed that the pressure in the glass column
returns to atmospheric pressure, and carefully opened the top cap of the glass column. Subsequently,
we carefully added the initial sample into the glass column not to overflow the initial sample.
7) Before flowing the mobile phase of 30 mL (HNO3 : MeOH = 2 : 8 (volume ratio)) into the glasscolumn, we turned on the fraction collector. The nuclide separation experiment was started.

Fig. 3 Chromatographic apparatus for nuclide separation experiment.
8) Following the flow of methanolic nitric acid solution, we ensured the flow of 30 mL or above 1.0
M HNO3 and ultrapure water of 30 mL through the glass column. Because the collected mobile phase
may be contaminated by Eu-152. We collected the eluted mobile phase in a special glass beaker aftercollecting 50 samples.
9) We fixed tightly the sample tubes using a handmade holder in Ge-Detector before measuring Eu152. The measurement time was 3 minutes per sample. We chose one value of energy of γ-ray from
Eu-152 (see Table 2).
Table 2 Main energy of γ-ray of Eu-152 and their emission ratios [12]Energy of γ-ray / MeVEmission ratio / %

0.122

28.6

1.408

21.0

0.964

14.6

10) We diluted the collected samples about 100 times with a 1.0 wt% HNO3 solution. Firstly, we
prepared 50 sample tubes containing each 1.0 wt% HNO3 solution of 10 mL. Then, the collected
samples of 0.1 mL were added into them.
11) We conducted the qualitative and quantitative analyses of the examined metal ions for all collected
samples with the ICP-MS analyzer.
12) After measurements, we wasted all the spent solutions into a 500 mL glass beaker in the fume
hood while taking care of handling an infrared heating and drying lamp and a digital hotplate. In caseof washing all sample tubes, we used deionized water. We separated and sorted laboratory waste intoburnable, flame retardant, nonburnable, inorganic, and organic and the wastes were temporarily kept
in the storehouse for spent radioisotopes. Finally, we filled out the form to ensure the storage of Eu7

Transactions on GIGAKU 5(1)(2018)05002/1-9

152 in the storehouse.
Based on these results, it is important to examine practically the validity of our proposed contents
to understand the Act on Prevention of Radiation Hazards due to Radioisotopes, etc. and the handlingof unsealed radioisotopes. Hence, we have described the graph showing the plots of I / I0 (I =concentration of metal ions, I0 = initial concentration of metal ions) against every elution volume andthe dead volume was calculated using Na ion (see Fig. 4). As mentioned above, the concentration of
metal ions was determined by using the ICP-MS analyzer and the Eu concentration was obtained using
both of ICP-MS and Ge-detector. The distribution coefficients, Kd and yields of metal ions were also
calculated [5]. The yield and Kd obtained from ICP-MS measurements of Eu element were identicalto those of Ge-detector measurements. As a result, it was found that the effluent volume of Eu element
increased, compared with other elements. In brief, this phenomenon means that Eu element strongly
adsorbed with AR-01 resin in 1.0 M HNO3/ MeOH solutions. Particularly, Sb element cannot be
detected up to effluent volume of 50 mL because of its strong adsorption ability for AR-01 resin. Sometechniques could be required to elute Sb element into mobile phase.

Fig. 4 Chromatograms of metal ions adsorbed on AR-01
in 1.0 M HNO3/ MeOH and 1.0 M HNO3 solutions
4. Conclusion
We have successfully prepared one of the novel curriculum to train practical and creative nuclear
engineers, combined systematically with the Act on Prevention of Radiation Hazards due toRadioisotopes, etc. and the handling of unsealed radioisotopes. These key points updated for our
department’s laboratory experiment have been introduced. We have also conducted the laboratory
experiment to confirm whether the revised contents work well or not. Specifically, we have practicallytested the well-known methods for surface contamination inspection in the controlled area before andafter laboratory experiment. The two types of inspections classified as survey and smear methods were
performed. As a result, it was found that the experiment rooms and apparatuses accompanying them,which were examined for laboratory experiment were not contaminated. Moreover, the experiments
for nuclide separation and identification of nuclides were also carried out in the methanolic nitric acidsolution. By considering a little difference of the calculated individual peak positions, we confirmed
to separate mutually many metal ions by using anion-exchange chromatographic technique. The yield
and Kd values obtained from ICP-MS measurements of Eu element were identical to those of Gedetector measurements.
Based on these results, it can be regarded that our proposing contents are useful for students to bepractical and creative nuclear engineers. On the other hand, we should lend an ear to the students’ andadvisers’ impressions and opinions before and after experiments and have to provide an education to8

Transactions on GIGAKU 5(1)(2018)05002/1-9

meet the needs of the times. After sufficient consideration, as necessary, it is very important to improveand update the present curriculum every year.
Acknowledgements
This work was partially supported by Nagaoka University of Technology Presidential Research
Grant (D) (No.7). The authors would like to thank Prof. Yoshinobu Matsumoto (Radioisotope Center,
Nagaoka University of Technology) for the periodic maintenance for the controlled area in theRadioisotope Center and Mr. Suki Hashimoto (Department of Nuclear System Safety Engineering,
Graduate School of Engineering, Nagaoka University of Technology) for fruitful discussions andtechnical support.
References[1] T. Shibata, T. Kosako, Y. Uwamino, T. Iimoto, and H. Yasuda, “Measurement and management
technology” in Introduction of Radiation, 8th ed. Tokyo, Japan: Tsusho Sangyo Kenkyusha, 2012,ch. 6, 8, sec. 6.3, 8.2, pp. 417-422, 497-498. (in Japanese)[2] M. Nomura, N. Higuchi, and Y. Fujii, “Mass dependence of uranium isotope effects in the U(IV)U(VI) exchange reaction,” J. Am. Chem. Soc., vol. 118, no. 38, pp. 9127-9130, Sep. 1996.
[3] T. Suzuki, M. Nomura, Y. Fujii, A. Ikeda-Ohno, T. Takaoka, and K. Oguma, “Zinc isotope
fractionation in anion exchange in hydrochloric acid solution,” J. Ion Exchange, vol. 21, no. 3, pp.
328-333, Sep. 2010.
[4] Y. Tachibana, Y. Yamazaki, M. Nomura, and T. Suzuki, “Molybdenum isotope fractionation in ion
exchange reaction by using anion exchange chromatography,” J. Radioanal. Nucl. Chem., vol. 303,
no. 2, pp. 1429-1434, Feb. 2015.
[5] Y. Tomobuchi, Y. Tachibana, M. Nomura, and T. Suzuki, “Effect of alcohols on separation behaviorof rare earth elements using benzimidazole-type anion-exchange resin in nitric acid solutions,” J.
Radioanal. Nucl. Chem., vol. 303, no. 2, pp. 1425-1428, Feb. 2015.
[6] T. Suzuki, Y. Tachibana, Y. Tomobuchi, J. Katakura, and T. Yamamura, “Separation of americium
and curium by using anion exchange resin supported in high porous silica beads in alcoholic nitricacid system,” in Proc. Global 2015, Paris, pp. 5219-1-5219-5.
[7] Y. Tachibana, et al., “Synthesis of tannic acid-type organic composite adsorbents toward advanced
ozone water purification method for simultaneous removal of various types of radionuclides,” inProc. 23rd IOA World Congress and Exhibition, Washington D.C., 2017, pp. 8.3-1-8.3-22.
[8] M. J. M. Wells and C. R. Clark, “Liquid chromatographic elution characteristics of some solutes
used to measure column void volume on C18 bonded phase,” Anal. Chem., vol. 53, no. 9, pp. 13411345, Aug. 1981.
[9] Y. Tachibana, T. Suzuki, M. Nogami, S. Okumura, M. Nomura, and T. Kaneshiki, “Tannic acidtype organic composite adsorbents for simultaneous removal of various types of radionuclides inriver water,” unpublished.
[10] W. M. Haynes, et al., “Fluid properties (Permittivity (Dielectric constant) of liquid),” in
Handbook of Chemistry and Physics, 95th ed. Boca Raton, Florida, United States: CRC Press,
2014, ch. 6, sec. 187, pp.6-189.
[11] H. B. Silber, R. Bakhshandehfar, L. A. Contreras, F. Gaizer, M. Gonsalves, and S. Tsmail,“Equilibrium studies of lanthanide nitrate complexation in aqueous methanol,” Inorg. Chem., vol.
29, no. 22, pp. 4473-4475, Oct. 1990.
[12] N. Ikeda, et al., “Nuclear and decay properties of main radioisotopes,” in Radioisotope Pocket
Data Book, T. Ido, et al., Ed. Tokyo, Japan: Maruzen Publishing, 2011, pp.69. (in Japanese)(Received: 23 October 2017, Accepted: 13 February 2018)9

Transactions on GIGAKU 5(1)(2018)05003/1-7

Folding Characteristics of Multiple-Scored Portion of Corrugated Fiberboard

1)

Haruya Yokoyama1* , Shigeru Nagasawa1
Dept. of Mechanical Engineering, Nagaoka University of Technology, Nagaoka, Japan*E-mail: s153090@stn.nagaokaut.ac.jp

This paper describes the bending moment resistance of scored portion of corrugatedfiberboard (Cfb) and the corresponded bulging behavior of scored portion. In order to reveal thefolding mechanism of scored Cfb using one-point type and three-point type die-set when varying
the indentation depth of attacker bite, two kinds of prototype die-set were developed and thefolding process was investigated using the folding test apparatus. The difference of one-pointtype and three-point type scoring was revealed as the characteristics of bending moment
resistance of scored Cfb and the occurrence limit of failure modes of folding with respect to thefolding direction.

1. Introduction

A corrugated fiberboard (Cfb) consists of outer/inner liners and corrugated mediums, and its
layered configuration is produced as several combinations, such as single face, double face (singlewall), double wall (twin cushion) and triple wall[1][2]. The Cfb is superior for the high strength-toweight ratio and provides a good shock absorption for transport products. It is one of the mostimportant materials for making packaging containers. Generally, a packaging container box madeof Cfb is composed of vertical wall panels and slotted flaps. When making the flaps and wall
panels, a sheet of Cfb is usually scored for making a folding line by a rotary type or platen typescorer machine using the three point type bites [3]. Regarding the scoring process (across to thecorrugated medium) and creasing process (parallel to the corrugated medium), there are known
several types of bite combination. The three point type, which is well used for making a scoreline, consists of one point (a convex bite) and two edge points (a concave-grooved anvil), while
the one point type is used normally for making a crease line [4]. In those cases, since the scoredside is located at the inside of formed box, the bending moment resistance of scored line tends tobe small for closing a flap, while the bending moment resistance is fairly large for opening theflap. Namely, the open wise bending resistance of scored line is usually larger than the close wise
bending resistance. Recently, the difference of flap opening/closing resistance of container boxes
becomes one of severe problems for workers in various packaging industries. This kind of
opening/closing resistance is desired to be even or at least similar in the both moving directions.
In this recent situation, a new processing method is desired for performing the evenness ofclosing/opening resistance of the scored lines of container boxes. Regarding the pattern of scoring
bite, the five point type is known for making a sort of multiple scored lines. Principally, it ispossible to make arbitrary-multiple scored lines for folding an open-purpose line and a closepurpose line, respectively. However, the performance of folding resistance [5][6] and the buckling
behavior of wall panel structure under a compressive test were not investigated sufficiently in thepast [7]. Also, the multiple point type bites of the scorer are used empirically depending on theapplication. There seemed to be no reports about the performing difference among the one-point
type, three-point type and five-point type scoring [3].
In this work, in order to reveal the relationship between the pitch pattern of multiple pointtype bites and the open/close wise folding resistance, two kinds of score line processing die-set(one-point type and three-point type) were developed and used for making a scored portion on
the specimen of A-flute [8] Cfb. A folding test [9] of the scored portion was experimentally carriedout for investigating the bending moment resistance and the crushing profile of the scored portion.
2. Experimental condition and method1

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The layered configuration of A-flute (single-wall, double-face) sheet was shown in Fig.1. The
three layers are composed of (1) a jute liner of basis weight 150 g∙m-2, thickness of 0.15mm (2) acorrugated medium sheet of basis weight 120 g∙m-2, thickness of 0.16mm and (3) a jute liner ofbasis weight 150 g∙m-2, thickness of 0.15mm. The wave length of A-flute was lA≈ 8.5mm, and thestacked height of A-flute plus upper/lower liners was tA= 4.9mm (4.81~4.99mm).
The specimen size of Cfb was prepared as a rectangle which has a width of 20mm and a lengthof 120mm, as shown in Fig. 1. Here, the effective wave number was chosen as 2 and the longitudinal
direction of 120mm was assigned to the cross machine direction (CD) of Cfb.

Fig.1 Layout of single wall corrugated, double face sheet.
One­point type scoring and three­point type scoring were processed by the use of the score line
processing die­set as illustrated in Fig.2. Here, the upper­attacker bite of apex angle 120° and thelower­receiver bites of apex angle 120° had a length of 50 mm and were made of ABSplusP430
thermoplastics [10], which had the hardness of 109.5 HRC, the tensile strength of 33 MPa, the yieldstress of 31 MPa, the tensile elastic modulus of 2.2 GPa. The counter face plate (flat anvil) was
made of SUS630, the hardness of which was 510HV. An indentation of the upper­attacker bite dwas chosen from 0.5 up to 4.5 mm with 0.5mm interval.
Blade holder

30.0

Blade holder

10.0

Length unit: mm

120°

7.6

R0.2

8.2

3.40

23.6

10.0

30.0

Work sheet

Detail of edgedWork sheet
Counter face plate
Base plate

Lower receiver blockBase plate(a) One­point type(b) Three­point typeFig.2 Schematics of score line processing die­set
Scored line

MD

30mm Clamped
zone
20mm

30mm Clamped
zone

20mm

Scored line

MD
Receiver edge line
120mm

40mm
120mm

40mm

(a) One­point type(b) Three­point type
Fig.3 Top (out­of­plane) view and layout of specimen for scoring and clamping on folding test
apparatus

2

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Figure 3 shows the dimensions of rectangle specimen (worksheet) of A­flute Cfb for scoringat the processing die­set and clamping on a folding apparatus. The specimen of A­flute Cfb wasscored with the indentation d and the pushing velocity of 0.05 mm∙ s-1, using the score line
processing die­set in a compressive testing apparatus.

Fig.4 General view of folding test apparatus CST­J­1[9]Reverse bending

Reverse bending

Load cell

Load cell
Fixture Normal
bending180°-q °Scoredzone

Scored Clamped
Normalzone
bending(a) One­point type(b) Three­point typeFig.5 Schematic diagrams of folding test and upper in­plane view of folded Cfb specimen
After that scoring, the bending line moment resistance M of the scored specimen was measured
with the folding angle q by using the folding test apparatus (Crease Stress Tester) CST­J­1 [9]. Figure
4 showed a general view of a specimen mounted on CST­J­1, while Fig.5 (a) illustrated the one­pointtype folding and Fig.5 (b) illustrated the three­point type folding when carrying out the normal wise
direction. Here, the end position of fixture was 10mm apart from the scored zone of the specimen as
shown in Fig.3 and Fig.5. The distance between the fixture end and the load cell was 60 mm when q=
0°. Namely, the arm length between the load cell and the scored position was 50mm. In the durationof folding test, the folding angle q was varied from 0 up to 90°, while keeping the average rotational
velocity as w= 0.2 rps. In Fig.5, when turning over the scored specimen, the folding angle q was also
varied from 0 up to 90° for the reverse bending mode. The experiment was carried out under thefollowing conditions: room temperature of 297K and room humidity of 50%RH. Number of samples
was three pieces for each case.
3. Results and Discussion
Table.1 (a) and (b) indicate the success rate of expected folding. The success rate was counted
when the scored line matched the folding position. In case of failure state, the folding position was at
the end position of fixture. Figure 6 shows the initial set­up states of the Cfb specimen scored with
the indentation d=1.0mm and 4.0mm. In the case of Fig.6, the folding direction of fixture was chosen
as the normal wise as illustrated in Fig.5. Since the reverse wise was simply processed using the upset
specimen with respect to the scored surface, its corresponded photographs were similar to Fig.6, except
for the opposite scored side. Figure 7 shows the normal wise 90° folded state of the Cfb specimenscored with the indentation d=1.0mm and 4.0mm, while Fig.8 shows the reverse wise 90° folded stateof that. Seeing Table 1 and Fig.7~8, several features were detected. (1) The three­point type stably
tends to be folded at a scored position (one of three scored positions) for both the normal and reverse
wise folding when choosing d/tA=0.1~0.92. (2) The one­point type was limited in d/tA>0.7 to make an
expected folding at the scored position for the reverse wise folding, although there was no limitation
to make the expected folding at the scored position for the normal wise folding when choosing
d/tA=0.1~0.92. These difference of folding behavior seems to be caused from the difference of scoredportion.
3

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Table 1 Folding state of scored portion (success rate % of 3 samples)(a) One­point type scoring
Indentation d /mm 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Normal bending
0 100 100 100 100 100 100 100 100
Reverse bending
0
0
0
0
0
0
100 100 100(b) Three­point type scoring
Indentation d /mm 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Normal bending
0 100 100 100 100 100 100 100 100
Reverse bending00
100 100 100 100 100 100 100

Fig.6 Side views of scored Cfb mounted on the folding tester in case of normal set­up at θ = 0°

Fig.7 Side views of scored Cfb in case of normal wise folding at θ = 90°

Fig.8 Side views of scored Cfb in case of reverse wise folding at θ = 90°(a) Initial score (b) Normal folding (c) Reverse folding
Fig. 9 Conceptual folding modes of three point type scored portion
Figure 9 illustrates the folding modes of three­point type scored portion. In the reverse wise
folding, one of scored positions which were processed by the receiver blades can be easily buckled asshown in Fig.9 (c). However, in the case of the one point type, since there is not any scored positions
on the inside (lower) surface for the reverse wise folding, the occurrence of buckling on the insidesurface becomes unstable against the opposite side scored position. Only when d/tA >0.7, namely incase of bending stiffness is sufficiently reduced at the scored position, the bent­buckling position
4

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10
9
8
7
6
5
4
3
2
1
0

Indentation d=1mm

Indentation d=4mm

0

10

20

30

40

50

60

70

80

90

Bending
momentMM/Nm
m-1
Bending
moment/Nm/mBending
momentMM/Nm/Nm/m
Bending
momentm-1

settles down at the scored position. Regarding the normal wise folding, both the one point type andthe three point type scored portions have almost the same structure with each other.
Figure 10 shows the bending moment resistance M per unit width of Cfb specimen (as therepresentative examples) when varying the folding angle q= 0°~90° under keeping the angular velocity
of w= 0.2 rps. Here, two cases (c), (d) of reverse wise folding with d=1.0mm were failed in formingof expected folding at the scored position. As the result, the peak maximum bending moment reachedabout 9 Nm∙m-1 when the span length was assumed to be L= 60mm due to the failure of deformationof scored position. When the folding occurred successfully at the scored position, the span length wasconsidered as L=50mm for calculating the bending moment M. When the folding angle q is larger than
60° with d=1mm in the graphs of (a),(b),(d), M tends to be increased, compared to the middle zone of
q= 20-60°. This resistance increasing appeared to be caused by the interference of bulged insidesurface. When d=4.0mm, since the scoring was sufficient for avoiding that interference, the responseof M was simply decreased with q. Generally, the peak maximum bending moment resistance is large
and unstable for making the inside bent-buckling in the reverse wise folding due to a lack or weakexistence of scored portion on the inside surface. However, it was found that the three-point typescoring by a deep indentation (e.g., d= 4.0mm) made the folding deformation stable as shown in Fig.6(d). This mechanism was already discussed above using Fig.9 (c).
10
9
8
7
6
5
4
3
2
1
0

Indentation d=1mm

Indentation d=4mm

0

10

20

Foldingq /°Foldingangle
angle
q /°

10
9
8
7
6
5
4
3
2
1
0

Indentation d=1mm

Indentation d=4mm
0

10

20

30

40

50

60

70

80

80

90

(b) Normal wise, three-point type90

Folding angle
Folding
angleq q/° /°Bending
momentBending
momentM [Nm/m]/Nm m-1

Bending
momentM M/Nmm-1
Bending
moment/Nm/m(a)Normal wise, one-point type

30 40 50 60 70
Foldingq /°q /°
Foldingangle
angle

10
9
8
7
6
5
4
3
2
1
0

Indentation d=1mm
Indentation d=4mm

0

10

20

30 40 50 60 70
Foldingq q/° /°
Foldingangle
angle

80

90

(c) Reverse wise, one-point type(d) Reverse wise, three-point typeFig.10 Relationship between bending moment and folding angle (representative examples), (a)Normal wise folding by one-point type score, (b) Normal wise folding by three-point type score,(c) Reverse wise folding by one-point type score and (d) Reverse wise folding by three-point typescore.
The relationship between the peak maximum bending moment Mpeak and the indentation depth d
was shown in Fig.11 (a)(b), while the corresponded peak folding angle qpeak was shown in Fig.11(c)(d). Here, the normal wise and the reverse wise folding were arranged for the one-point and threepoint type scoring, respectively.

5

10
8

Failure of folding at scored position
Reverse wise
folding6
Eq.(1)4
2
0

Eq.(2)
normalNormalbendingwise folding

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Indentation depth
Indentation
depthd /mm
d /mm

10

Peak maximum bending moment-1 [Nm/m]
Maximum
momentMpeakbending/NmȉmPeak maximum bending moment-1
Mpeakbending/NmȉmMaximum
moment [Nm/m]Transactions on GIGAKU 5(1)(2018)05003/1-7

6
42

Normal wise folding

12
8
4
0

normal bending

Reversewise folding
reverse bending

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Indentation depth
Indentation
depthd /mm
d /mm

Eq.(4)
Eq.(3)
normalNormalwise folding
bending00 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Pushing amount[mm]d /mmIndentation
depth(b) Mpeak by three-point typeFolding angle at peak maximum
qPeak/°[deg]peakangle

Folding angle at peak maximum
qPeak/°[deg]peakangle

16

Reverse wise
folding8(a) Mpeak by one-point type20

Failure of folding at scored position

20
16
12

normal bending
Reversewise folding
reverse bending

8
4

Normal wise folding

00 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
Pushing amount
Indentation
depth[mm]d /mm(c) qpeak by one-point type(d) qpeak by three-point typeFig.11 Peak maximum bending moment and its folding angle for indentation depth of d=0.5~4.5mm
Mpeak = -6.96(d/tA) +6.95
Mpeak = -13.9(d/tA) +17.4
Mpeak = -8.19(d/tA) +8.53
Mpeak = -8.93(d/tA) +10.1

for 0.2< d/tA <0.92
for 0.6< d/tA <0.92
for 0.2< d/tA <0.92
for 0.2< d/tA <0.92

(1)
(2)
(3)
(4)

Detected features were as follows. (1) Mpeak tends to decrease with d for both the normal andreverse wise folding. Except for the failure mode of folding, Mpeak was estimated using a linear
approximation for each case. Four equations were derived as Eq. (1)~(4). (2) The difference of Mpeak
between the normal and reverse wise folding was remarkably large (4~7 Nm∙m-1) in case of one-pointtype when d > 2mm, while the difference of them was relatively small (about 1.5 Nm∙m-1) in case of
three-point type. In other words, seeing the gradient − ∂Mpeak/∂(d/tA) , that of normal wise in onepoint type was about a half of that of reverse wise and that of normal wise in three-point type wasalmost equal to that of reverse wise. (3) Seeing the failure states of folding position, the upper-boundbending moment resistance appeared to be 9 or 10 Nm∙m-1. This value was the nominal bending
strength of A-flute Cfb without any scoring. (4) Comparing Mpeak of the normal wise in (a) and thatof the normal wise in (b), the latter was a little larger than the former, and also the gradient− ∂Mpeak/∂(d/tA) of the latter 8.19 was larger than that of the former 6.96. This difference seems to becaused from the fixing structure of the attacker bite and the receiver. Since three-point type (latter) had
two wedge bites on the receiver, the receiver bites were easily indented against the specimen, while
the counter plate support the specimen without any damages. As the result, the attacker bite of onepoint type (former) tended to be strongly indented to the specimen. This effect seems to generate thedifference of bending moment and its gradient. (5) The peak position qpeak of three-point type wasstably 6~12° for both the normal and reverse wise folding, while that of one-point type was 6~16° forthe normal wise, but that was restricted in a narrow range of 4~8° in the case of reverse wise folding.
From the aspect of application works (e.g., when opening a flap of box), the peak position of qpeak
6

Transactions on GIGAKU 5(1)(2018)05003/1-7

ought to be stable and similar with the normal and the reverse wise folding. Synthetically, the threepoint type seems to be superior for opening/closing performance of scored portion of Cfb.
4. Conclusions
Two scoring methods, one-point type and three-point type scoring of A-flute corrugatedfibreboard (Cfb) have been experimentally investigated using a prototype flatbed die-set made of
3D printing thermoplastics. Seeing the in-process deformation and bending moment resistance offolded portion at scored position, the following results were obtained.
(1) In the normal wise folding (scored surface is located on the inside of folding), 10%
indentation depth of attacker bite is at least required for performing the successful folding at thescored position in both the one-point and three-point type scoring. In the reverse wise folding(scored surface by the attacker bite is opposite against the inside of folding), the failure state of
expected folding occurred when the indentation depth of attacker bite was less than 60% of theheight of Cfb in the case of one-point type scoring, while the failure state occurred for theindentation depth was less than 20% of the height of Cfb in the case of three-point type scoring.
(2) The bending moment resistance of scored portion is decreased with the indentation depth of
attacker bite. The effect of the bite indentation depth on the bending moment response wasexperimentally characterized using a linear approximation method.
(3) For both one point type and three point type, the peak maximum bending moment of reverse
folding was apt to be larger than that of the normal folding. In the case of one-point type, the differenceof peak maximum bending moment between the normal and reverse wise folding was remarkably
large. In the case of proposed three-point type, the difference of peak maximum bending moment
between the normal and the reverse wise folding was negligible. This mechanism was revealed andexplained using a conceptual deformation model.

References[1] R., Steadman, “Handbook of Physical Testing of Paper”, 2nd ed., Characterization of CorrugatedBoard, Vol.1, (2002), pp.571-574, Marcel Dekker.
[2] A. Dekker, “Handbook of Paper and Paperboard Packaging Technology”, 2nd ed., Corrugatedfiber board packaging, (2013), pp.313-321, Wiley-Blackwell.
[3] S., Igarashi, “Packaging technology of corrugated board”, Practical part, (2012), pp.245-256 (inJapanese), Nippo publishing.
[4] S. Nagasawa and Y. Komiyama, “Effect of Scoring Condition on Creasing Characteristics ofDouble-wall Corrugated Board”, Journal of Advanced Mechanical Design, Systems, andManufacturing, Vol.6 No.7, (2012), pp.1263-1272.
[5] H. Ishibuchi, S. Nagasawa, A. Yoshizawa, and Y. Yoshitani, “Three-dimensional Bending Stress
Analysis for Corrugated Fiberboard Sheet”, Transactions of Japan Soc. Mech. Eng. Series A,
Vol.60 No.580, (1994), pp.2774-2781.
[6] H. Ishibuchi, S. Nagasawa, A. Yoshizawa, and Y. Yoshitani, “Study of Bending work ofCorrugated Fiberboard Sheet”, Journal Japan Soc. Technol. Plasticity, Vol.36 No.416, (1995),
pp.917-925.
[7] S. Nagasawa, M. Yamashita, “Effects of one point type scoring depth on compressive strength ofa folded flap-panel structure of an AB-flute corrugated paperboard”, Proc. the 5th International
Conference on Engineering, Energy and Environment, Bangkok, Thailand, (2017), pp. 236-241.
[8] D. Twede, S. E. M. Selke, D.P. Kamdem, D. Shires, “Cartons, Crafts and Corrugated Board”, 2nded., DEStech Pub., (2015), pp.460-464.
[9] Katayama Steel Rule Die Inc., “Crease Stress Tester CST-J-1”, (accessed on September, 2016),
http://diemex.com/sale/cst.html.
[10] Stratasys Ltd., “ABSplus for Mechanical Strength and Multi-Colors”, (accessed on January,2018),
http://www.stratasys.com/-/media/files/material-spec-sheets/mss_fdm_absplusp430_1117a.pdf(Received: 12 October 2017, Accepted: 7 March 2018)7

Transactions on GIGAKU 5(1)(2018)05004/1-8

Preparation and Characterization of Cellulose Hydrogel Films from
Myanmar Thanaka Heartwood
Cho Cho1*, Takaomi Kobayashi2
Department of Chemistry, Yenanchaung Degree College, Myanmar
2
Nagaoka University of Technology, Department of Materials Science and Technology, Japan
E-mail: chocho.urc@gmail.com, E-mail: takaomi@nagaokaut.ac.jp
1

Waste thanaka heartwood was used as a starting material which was chemically pretreated using sulphuricacid (H2SO4) and sodium hydroxide (NaOH). When this sample was bleached by sodium hypochlorite(NaOCl), treated thanaka fibers were obtained. FTIR and SEM measurements were utilized to characterize theproperties of pretreated samples. Following this, solvent exchange processes were performed making use ofwater, ethanol and DMAc respectively. Using a dimethylacetamide/lithium chloride (DMAc/ LiCl) system, it
became possible to obtain cellulose hydrogel solutions. The cellulose hydrogel films were prepared by phase
inverse method without cross-linker. The resultant hydrogel films were transparent and flexible. Then, the effecton the properties of three types of hydrogel films (TW-RT, TW-40,TW-50) depending on the bleaching process
at different temperatures (room temperature RT, 40 ͦ C, 50 ͦ C)of thanaka fiber was comparatively studied. It was
found that water contents were in the range of 162.50 -185.71 % and the poly dispersity index (PDI) in the rangeof 4.02 – 5.54. Viscoelastic data showed the deformation of hydrogel films-TW-50 being lower than that of films
TW-40 and TW-RT. From our observations, thanaka cellulose hydrogel could transform to hydrogel films byphase inversion method and these films had the potential to be used in environmental friendly and biocompatible
products for tissue regeneration.

1. Introduction
Recently, regeneration of agro biomass cellulose hydrogel has become especially attractive as it can beeasily transformed into advanced materials. Among them, hydrogels prepared from collagen, chitosan andother biomass polymers are capable of yielding material including matrices for repairing and regenerating awide variety of tissue and organs used in “tissue engineering”[1-3]. Hydrogels consisting of hydrophilicpolymer networks can retain high water contents; meaning that it can absorb water from 10-20% up to
thousands of times their dry weight in water. Various hydrogels originated from natural polymers have beenused in hyaluronate [4,5] alginate [6],starch [7], chitosan, cellulose[10-14]and their derivatives. They haveshown potential applications in biomaterial field because of their ability to be used safely, along with theirhydrophilicity, biocompatibility and biodegradability. In the aforementioned polymers, cellulose is the mostabundant renewable resource on earth [15,16]. Moreover, it is numerous new functional materials that havebeen using a broad range of applications because they are environmentally friendly and biocompatible
products [17,18]. Extremely limited work, however, has been performed by using cellulose fibers in orderto prepare hydrogel films. Cellulose hydrogel films prepared from bamboo [19], agave fiber[20], sugarcane
bagasse [21] and corn cobs[22] have been reported by researchers. They portrayed that these films have goodbio and cytocompatibilities [19-22]. Moreover, Tovar-Carrillo et. al purified cellulose with Agave bagasse,studied the effect of lithium chloride and sodium hypochloride treatment on agave cellulose and used this toelaborate cyto and biocompatibility of hydrogel films[23,24]. In these cases, agave tequilana bagasse wasused as the regeneration source for cellulose hydrogel. Nakasone et.al examined sugarcane bagasse forhydrogel preparation [21]. In the present work, the effect of temperature on the properties of obtained
cellulose hydrogel films prepared from thanaka is focused, because each plant has its own unique type ofcellulose. In addition, thanaka is one of the valuable and precious natural resources in Myanmar since it
has been using for many years as a natural cosmetic in daily lives. Both female and male apply groundedthanaka paste on their faces as well as bodies for the purposes of protection against ultraviolet (UV)
rays, also for its cooling sensations and feeling of freshness. Thanaka trees usually grow in the upper
portions of Myanmar especially in Shwe Bo, Pakokku, ShinmaTaung and Monywa. It is worthy to notethat thanaka has strong anti-inflammatory, significant antioxidation, mild tyrosinase inhibition andantibacterial activities [25]. Commercial products of thanaka can be available in various forms such as
powder, liquid, paste and bark in Myanmar. Generally only the outer part, the bark of thanaka, is used
for these products. Thus, the heartwood usually becomes a waste material after the powder and essence
are extracted.
Since biomass-based cellulose has an important role these days, they are an attractive strategy
for reproducing advanced materials. Such approach in cellulose hydrogel films produced from various1Transactions on GIGAKU 5(1)(2018)05004/1-8

biomasses is interesting, but no one has published the preparation of hydrogel films from Myanmar’s
thanaka. Therefore, the aim of this work is to fabricate the thanaka cellulose hydrogel films in effective
cosmetic materials like facial masks and medical plaster.

2. Experimental Methods
2.1. Materials
Thanaka samples were obtained from Pakokku, Myanmar. As solvent, N,N,
Dimethylethylenediamine(DMAc) was purchased from TCI, Tokyo, Japan, and stored for more than 5 days
over potassium hydroxide before being used. Lithium chloride was dried in a vacuum oven at 80°C for 12hours before use. Ethanol, sodium hydroxide, sodium hypochlorite and sulfuric acid were purchased from
NacalaiTesque, Inc. Tokyo, Japan.

2.2. Thanaka Treatment
Thanaka trunk was crushed and tipped (Figure 1). The samples were then washed three times with
distillated water and then dried in an oven at 50°C. The thanaka fibers were treated with acid. 10g of thesample was immersed in 500mL of 4%H2SO4 and stirred for 2hours at 90°C. Following the acid treatment,
the sample was washed with abundant distilled water five times to remove any residue of the sulfuric acidsolution.
After filtering the sample, 500mL of 10 vol% of sodium hydroxide solution was added. Then thesolution and the tipped samples were stirred for 24 hours at 90°C until a black liquor solution was obtained.
Afterwards, the tipped sample was washed five times with abundant distilled water to eliminate all traces ofthe sodium hydroxide solution. The remaining fiber was then immersed in distilled water while stirring atroom temperature until pH is neutral. The sample is filtered once more, bleached by sodium hypochloride toobtain the light colored fibers for preparation of cellulose solution. In the bleaching process, the sample was
immersed in 500mL of 10 vol% sodium hypochloride solution and stirred for 2 hours at room temperature,
40°C and 50°C. After the fibers were obtained, they were washed five times with abundant distilled waterand dried under vacuum for 2 days.

Thanaka raw material(i) cut, washed,(ii) dried 50 ºC
Acid treatment(i) 4% H2SO4 , 90 º C, 2 h(ii) washed with D-water to eliminate residue H2SO4
Alkali treatment(i)10% NaOH,90 ͦ C,24 h(ii) washed with D-water to eliminate residue NaOH(a)
Bleaching

(b)

(c)

(i)10% NaOCl, 2h, (RT, 40 ͦ C, 50 ͦ C)(ii) washed with D-water to eliminate residue NaOCl(iii) dried under vacuum for 2 days

Cellulose fiberFig.1 Schematic Diagram for Preparation ofThanaka Cellulose Fiber

Fig.2 (a) TW-RT = Cellulose Fiber Sample
Prepared at Room Temperature(b) TW-40 = Cellulose Fiber Sample
Prepared at 40 ͦ C(c) TW-50 = Cellulose Fiber Sample
Prepared at 50 ͦ C

2.3. Preparation of Cellulose Solution
The treated fibers were used for the following process in the preparation of the thanaka cellulose in
DMAc/LiCl solution [28]. The treated fiber (1g) was suspended in 300mL of distilled water and stirred
overnight to allow thorough swelling of the fiber. After water was removed from the suspension by use of2

Transactions on GIGAKU 5(1)(2018)05004/1-8

an adapter glass filter under vacuum, ethanol (300 mL) was added to the swelled fiber and the mixture wasstirred for 24 hours. The 300 mL of ethanol was removed, and the treated fiber was added to 300 mL of
DMAc. This fiber was then left overnight under the stirred condition. Dried lithium chloride and DMAc
were added to the swelled thanaka fiber to obtain a 1wt% concentration of the treated thanaka solution.
Following this, the mixture was stirred at room temperature for 3 days until a viscous cellulose solution was
obtained. Three types of cellulose solutions (TW-RT, TW-40 and TW-50) were obtained under the sameprocedure.
2.4. Preparation of Cellulose Hydrogel Films
For the preparation of hydrogel films, 10g of the cellulose solution was poured into a glass tray (10 cm
diameter), and kept again for 24 hours in a container filled with ethanol by using phase inverse method [28].
With time, gradual coagulation of cellulose was observed because of phase inversion of the cellulose fromliquid to solid gel in ethanolic vapor [29] and cellulose hydrogel film was obtained in the petri dish. The
resultant hydrogel film, as shown in Figure 3, was washed with excess water and then placed in distilledwater for 24 hours to remove DMAc and lithium chloride. Then, the obtained hydrogel films were kept in aplastic container filled with distilled water for further experiments. Three types of cellulose hydrogel films(TW-RT, TW-40, TW-50) are prepared by similar procedures.

(a)

(b)

(c)

Fig.3 (a) Transparent Cellulose Hydrogel Film(b) and (c) Cellulose Hydrogel Film Showing Flexibility andStrength for TW-50 Film
2.5. Characterization of Hydrogel Films
The formation of prepared samples was monitored by FTIR spectrometer and scanning electron
micrograph (SEM). The structural changes of the samples were analyzed by FTIR 4100 series (Jasco Corp.
Japan) using KBr pallet method in the Mid IR radiation with the wave number from 4000 cm-1 to 400 cm-1
range, using a resolution of 4.0 cm-1. Surface morphology of the samples was investigated by SEM (JSM
5300LV Scanning Microscope, JEOL, Japan).The X-ray diffraction (XRD) patterns of Thanaka raw sample
and pretreated cellulose fibers were recorded with CuKα radiation (λ = 1.5418) at 40 kV and 30mA in therange of 2θ = 10°- 40° by X-ray diffractometer (Smart Lab, Rigaku, Japan). The samples were dried in
vacuum at room temperature before measurements. The crystalinity index (CI) was calculated according toreported method using the following equation:
CI (%) = (I002–Iam)/I002) × 100
where I002 is the maximum intensity of the peak (002) lattice diffraction and Iam is the intensity of diffraction
attributed to amorphous cellulose [30].
The relative molecular weight and the distribution for resulting celluloses were determined by gel permeation
chromatography (GPC)[31]. From the calibration curve of polystyrene standard, the values of Mn, Mw andpolydispersity index could be calculated. Here, the abbreviation is as follows: Mi=molecular weight,
Ni=number of molecule, Hi=peak height, Mn=number average molecular weight, Mw=weight averagemolecular weight and PDI=polydispersityindex.
Water content of the hydrogel films were determined by weighing dry and wet samples by the procedurethat follows. Disk samples with 5 mm diameter were cut from cast films and dried in vacuum oven for 24hours and weighed (W0). Then, samples were immersed in distilled water for 36 hours. After this process,films were removed from water and wrapped with filter paper in order to remove excess water and weighedagain (W1). Finally, the equilibrium water content was calculated from the wet (W1) and dried (W0) hydrogelfilms. For each sample, four independent measurements were made and the average calculated.
3

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Water content (%) = (W1–W0)/ W0x 100
Viscoelasticity of the hydrogel film, 2 cm in diameter and 5 mm in thickness, was determined by Auto
Paar-Reoplus equipment(AutonPaar Japan, Tokyo) in wet conditions at 37 °C.

3. Results and Discussion
3.1. Properties of Thanaka Celluloses

Fig. 4 FTIR Spectra of (a) Thanaka Raw Sample (b) Thanaka Wood (c) Acid Treated Sample (d) Alkali
Treated Sample and (e) Cellulose Fiber
In Figure 4, FTIR spectra showed remarkable differences between the raw sample and obtained treatedsamples. All samples presented the strong broad band in 3354 cm-1 due to the O-H stretching vibration,
giving considerable information concerning the hydrogen bonds. The strong bands at 2915cm-1 and 2850
cm-1 were due to C-H stretching vibration referring to CH2group [32].The absorption band at 1730 cm-1
indicated the C=O stretching in carbonyl group of pyrone [33]. Appearance of the band 1640-1618 cm-1 wasowing to relative pure ring stretching mode similar to the aromatic ring C=C stretching in benzene as wellas in pyrone ring. This might be due to presence of coumarin and its derivatives which are active compoundsof thanaka [34]. From the comparison of the presented FTIR spectra, the peaks around 1510 and 1520 cm−1
showed the presence of lignin and lignocellulose in the initial raw sample [35,36]. Moreover, the band ataround 1200 cm-1 disappeared in treated fiber assigning to the removal of hemicelluloses. The changes ofthe bands in the region from 1423 cm-1 to 1080 cm-1were due to the removal of lignin and hemicelluloses[37,38]. This clearly indicated that the amount of lignin from the thanaka raw sample was successfully
reduced by the chemical and temperature treatments.
SEM microphotographs of treated samples are shown in Figure 5. The SEM micrograph of thanaka
wood sample showed the major constituents of natural fibers in Figure 5(a). The SEM images of treatedsamples in Figures 5(b) and (c) have changed in their morphologies due to the removal of lignin andhemicelluloses. From Figure 5(d) (e) and (f), it can be seen that the main structural units of cellulose in theplant wall which consists of cellulose microfibrils bonded together in a polymeric matrix. The cellulose
fibrils had average diameters of approximately 0.15 μm and up to 20cm or more in length [39].
According to the investigation of Adap et al, 2011, the cellulose, hemicellulose and lignin percentages
were 37%, 21% and 24% in the wood sample. However, they were changed to 49%, 15 % and 18 %respectively after being pretreated with acid and sodium hydroxide solution caused by dissolution of
amorphous materials from the initial wood sample [40]. Xue et al, 2007 also mentioned that pretreatment of
sodium hydroxide tended to decrease the lignin and hemicellulose which in turn increased the content ofcellulose [41]. The result was that the individual cellulose fibrils became clear due to bleaching processes
as shown in Figures 5(d)(e) and (f).

4Transactions on GIGAKU 5(1)(2018)05004/1-8

Fig. 5SEM Images of(a)Thanaka
Wood
(b)
Acid
TreatedSample (c)AlkaliTreatedSample (d) TW-RT (e) TW-40 (f) TW-50
In order to evaluate the effect of the pre-treatment condition on the crystalline structure of the cellulose
fibers, XRD measurement was carried out. Figure (6) shows the XRD patterns of raw thanaka and the treatedfibers. The patterns (a) to (d) exhibited typical crystalline lattice of cellulose with peaks at 22.6° and 16.1°[42]. This cellulose crystalline can be found in natural plant cellulose. In the crystalinity of thanaka andcellulose fibers, the peak ratio showed that raw thanaka and pre-treated fibers were for 68.5%, 82.1%, 84.2%,
and 85.4%, respectively. The increment of the crystalinity in the pre-treated fibers was attributed to theremoval of hemicelluloses and lignin by sodium hydroxide and sodium hypochloride treatment, indicating
especially higher purity of alkali treated fibers.
500
400

d

300

c

200

b

100

a

0
10

30

50

70

90

Fig.6 XRD X-ray Diffraction Patterns of (a) Raw Thanaka (b) Acid Treated (c) Alkali Treated Sample and(d) Cellulose Fiber
In Table (1), the values of number average molecular weight, weight average molecular weight and poly
dispersity index for thanaka cellulose solution samples can be seen. The polydispersity index is used as ameasure of the broadness of a molecular weight distribution of a polymer, and is defined by: Polydispersity
index = Mw/Mn.
The larger the polydispersity index, the broader the molecular weight [31]. It was found that the sample
prepared at 50ºC (TW-50) had better distribution of molecular weight and more polydispersity index thanthe other samples. Therefore, it is meaningful to relate between the nature and physical properties of thecellulose samples and their treated temperatures. In other words, the bleaching temperature affected theproperties of the resulting cellulose samples.
Table1. Properties of the Chemically Treated Thanaka Celluloses
Sample
TW-RT
TW-40
TW-50

NaOCl
Treatment (ºC)
25
40
50

Yield(%)

Mn

Mw

Mw/Mn=PDI

21.5
15.0
12.5

149000155000170000599000764000943000

4.02
4.93
5.55

Water
Content(%)
185.71
175.00162.503.2. Properties of Thanaka Hydrogels
As shown in Table (1), the values of water content significantly decreased with increasing temperature.
These differences significant to TW-RT film was compared with TW-40and TW-50. All of the samples
reached equilibrium after 36 hours in the swelling process. The values of water content were found to be5Transactions on GIGAKU 5(1)(2018)05004/1-8

185.71%, 175.00 % and 162.50%,as the temperatures of hydrogel film were at RT,40 ºC and 50 ºC
respectively. Thus at room temperature, the treated sample was able to retain water hence softening thesample more than the others.

(a)

(b)

Fig. 7(a) Relationship between storage elastic modulus(G'),loss elastic modulus(G''),and strain for theThanaka cellulose hydrogel films prepared at different temperatures(b)Relationship between tangent δ and strain for the cellulose hydrogel films
Regarding viscoelasticity measurements, it was known that the viscoelastic response to the deformation ofcellulose hydrogel films only occurred under momentary deformation. Figure 7(a) shows the viscoelastic
data for the thanaka hydrogel films prepared at different bleaching temperatures. It was noticed that the
deformation of hydrogel films had G' = 8x104 and G'' = 7x103 Pa, 5 x103 and 3x103 Pa for TW-50,TW-40
and TW-RT respectively at 1x10-2 to 3% strain [43]. The loss elastic modulus (G'') of TW-RT was lower
than that of the others. This meant that the elastic nature was low and deformation was high in TW-RT
sample. It appeared that the hydrogel film TW-RT showed soft nature in the deformation during the strain
sweep measurements. Under the prolonged deformed condition, the hydrogel film was observed to recover
into its original shape. Figure 7(b) shows the relationship between strain sweep and tanδ, which was definedas G"/G'. If the value of tanδ was between 0 and 1, the sample would be a viscoelastic solid. If the value oftanδ was 1, the sample would be at gel point. For values above 1, the sample behaved like a viscoelastic
liquid [43]. In the case of strongly cross-linked gel materials, tanδ >1 meant fracture of material or inability
to follow deformation, because rigid polymer networks might not flow. In the prepared cellulose hydrogel,cross points of G' and G" (tan δ = 1) shifted towards low strain range in order of strength of fiber treatment.
It was regarded that these viscoelastic changes were caused by the change in the interaction of polymer
chains. As a result, pretreatment at 50°C during the sodium hypochloride treatment strengthened thecellulose hydrogel film. Therefore, the fiber structure of the hydrogels was influenced by the pretreatment
condition.
4. Conclusions
Thanaka cellulose hydrogel films were successfully prepared by phase inversion of the DMAc solution with
LiCl. The effect of the sodium hypochloride bleaching on the resultant celluloses was investigated in the
fabrication hydrogels. These prepared samples were characterized by FTIR, SEM and XRD which showedthat the amount of lignin and hemicelluloses from the thanaka wood sample was successfully reduced bychemical and temperature treatments. Based on the viscoelasticity data, it was found that the temperature
affected the properties of cellulose hydrogel films, especially for loss elastic modulus(G''). When thetemperature was increased, deformation of the films decreased and thus elasticity increased.
Acknowledgements
I would like to pay acknowledgement to Prof. Dr. Takaomi Kobayashi of the Department ofMaterials Science and Technology, Nagaoka University of Technology, Nagaoka, Japan, for his invitation,kind support, supervision, guidance and encouragement throughout my study in Japan. I would also like toextend special thanks to Prof. Dr. Pho Kaung, Rector of University of Yangon for his permission to carry on
with this research collaboration. I am greatly appreciative of Dr. Kazuki Nakasone, Department of Materials
Science and Technology, Nagaoka University of Technology, Nagaoka, Japan, for his help and valuableadvice. My special thanks go to all members of Materials Science Lab for their research instruments,
unconditional help and advice.

6

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References[1] V. F. Sechriest, Y. J. Miao, C. Niyibizi, A. Westerhausen-Larson, H. W. Matthew, C. H.Evans, F.
H. Fu, and J. K. Suh, “GAG-augmented polysaccharide hydrogel: a novel biocompatible andbiodegradable material to support chondrogenesis”, Journal of Biomedical Materials Research,Vol.
49, pp.534,1999[2] M. Yamamoto, Y. Tabata, and T. Ikada, “Growth factor release from gelatin hydrogel for tissue
engineering”, Journal of Bioactive and Compatible Polymers, Vol. 14, pp. 474, 1999.
[3] L. G. Griffith, “Polymeric biomaterials”, ActaMateriala, Vol. 48, pp. 263, 2000
[4] D. Campoccia, P. Doherty, M. Radice, P. Brun, G. Abatangelo, and D. F. Williams, “Semisynthetic
resorbable materials from hyaluroran esterification”, Biomaterials, Vol. 19, pp.2101, 1998
[5] G. D. Prestwich, D. M Marecak, J. F. Marecak, K. P. Vercruyse, and M. R. Ziebell, “Controlled
chemical modification of hyaluronic acid”, Journal of Controlled Release, Vol. 53, pp. 93, 1998
[6] L. S. Nair, and C. T. Laurencin, “Biodegradable polymers as biomaterials”, Progress in Polymer
Science, Vol.33, pp. 1059, 2008[7] J. E. Morris, R. Fischer, and A. S. Hoffman, “Affinity precipitation of proteins with polyligands”,
Analytical Biochemistry, Vol. 41, pp. 991, 1993
[8] X. Liu, L. Ma, Z. Mao, and C. Gao, “Chitosan-based biomaterials for tissue repair and regeneration”,
Advances in Polymer Science, Vol. 244, pp. 81, 2011
[9] L. L. Llooyd, J. F. Kennedy, P. Methacanon, M. Paterson, and C. J. Knill, “Carbohydrates polymers
as wound management aids”, Carbohydrate Polymers, Vol. 37, pp. 315, 1998
[10] M. I. Vazquez, R. De Lara, and J. Benavente, “Chemical surface diffusional, electrical and elastic
characterization of two different dense regenerated cellulose membranes”, Journal of Colloids andInterface Science, Vol. 328, pp. 331, 2008[11] K. J. Edgar, C. M. Buchanan, J. S. Debenham, P. A. Rundquist, B. D. Seiler, M. C. Shelton,and D.
Tindall, “ Advanced in cellulose ester performance and application”, Progress in Polymer Science,Vol. 26, pp. 1605,2001[12] A. L. Dupont, C. Egasse, A. Morin, and F. Vasseur, “Comprehensive characterization of cellulose
and lignocellulose degradation products in aged papers: Capillary zone electrophoresis of low
molar mass organic acids, carbohydrates, and aromatic lignin derivatives”, Carbohydrate Polymers,
Vol. 68, pp. 1, 2007.
[13] C. N. Saika, T. Goswani, and A. C. Ghosh, Esterification of high α cellulose extracted from
Hibiscuscannabinus L”, Industrial Crops and Products,Vol. 4, pp. 233, 1995.
[14] A. Svensson, E. Nicklasson, T. Harrah, B. Panilatis, D. L. Kaplan, M. Brittgerg, and P.Gatenholm,“Bacterial cellulose as a potential scaffold for tissue engineering of cartilage”, Biomaterials, Vol.
26, pp.419, 2005[15] B. Mulder, J. Schel, and A. M. Emons, “How the geometrical model for plant cell wall formation
enables the production of a random texture,”Cellulose, Vol.11, pp. 395, 2004[16] L. Yan, and Z. Gao, “Dissolving of cellulose in PEG/NaOH aqueous solution”, Cellulose, Vol.15,
pp. 789, 2008[17] T. Heinze, R. Dicke, A. Koschella, A. H. Kull, E. A. Klohr, and W. Koch, “Effective preparationof cellulose derivatives in a new simple cellulose solvent”, Structure and Engineering of Cellulose,Vol. 201, pp.627-631,2000.
[18] T. R. Dawsey, and C. L. McCormick, “The lithium chloride/dimethylacetamide solvent forcellulose: a literature review”, Journal of Applied Polymer Science, Vol. 60, pp. 63, 1996.
[19] K.L.Tovar-Carrillo, M. Tagaya and T.Kobayashi, “Bamboo Fibers Elaborating Cellulose HydrogelFilms for Medical Applications” Journal of Materials Science and Chemical Engineering, Vol. 1,
pp. 7-12, 2013.
[20] K.L.Tovar-Carrillo, M. Tagaya and T. Kobayashi, “Fibroblast Compatibility on Scaffold
Hydrogels Prepared from Agave Tequilana Weber Bagasse for Tissue Regeneration,” Industrial &Engineering Chemistry Research, Vol. 52, pp. 11607-11613, 2013.
[21] K. Nakasone, S. Ikematsu and T. Kobayashi, “Biocompatibility Evaluation of Cellulose Hydrogel
Film Regenerated from Sugar Cane Bagasse Waste and Its in Vivo Behavior in Mice”,Industrial
and Engineering Chemistry Research, Vol. 55, pp. 30-37, 2016.
[22] R.L.Shogren, S.C. Petersona, K.O.Evans, and J. A. Kenar, “Preparation and characterization ofcellulose gels from corn cobs” Carbohydrate Polymers, Vol.86, pp. 1351- 1357, 2011.

7

Transactions on GIGAKU 5(1)(2018)05004/1-8[23] K.L.Tovar-Carrillo, K. Nakasone, S. Sugita, M. Tagaya and T. Kobayashi, “Effects of Sodium
Hypochloride on Agave Tequilana Weber Bagasse Fibers Used to Elaborate Cyto andBiocompatible Hydrogel Films,” Materials Science and Engineering C.42, pp. 808-815, 2014.
[24] K.L.Tovar-Carrillo, S. Sugita, M. Tagaya and T. Kobayashi, “Fibroblast Compatibility on Scaffold
Hydrogels Prepared from Agave Tequilana Weber Bagasse for Tissue Regeneration” Industrial
and Engineering Chemistry Research, Vol. 52, pp.11607-11613, 2013[25]S. Wangthong,T. Palaga,S. Rengpipat,S.P. Wanichwecharungruang,P.
Chanchaisak and
M.Heinrich, “Biological activities and safety of Thanaka (Hesperethusacrenulata) stem bark”,
Journal of Ethnopharmacology.,11;132(2):466-72, 2010.
[26] Wenzel and R. Staudenmaier, “Cellulose Based Scaffold Materials for Cartilage Tissue
Engineering,” Biomaterials, Vol. 27, No. 21, pp. 3955-3963, 2006.
[27] A.K. Mohanty, M. Misra, and G. Hinrichsen, "Biofibres, biodegradable polymers andbiocomposites: An overview", Macromolecular Materials and Engineering, Vol. 276-277, pp. 1–
24, 2000[28] A. M. Striegel, “Theory and applications of DMAc/LiCl in the analysis of polysaccharides”,
Carbohydrate Polymers, Vol. 34, pp. 267-273, 1997[29] L.T. Son, T. Kobayashi, “Hollow-fiber membrane absorbents embedded molecularly imprinted
polymeric spheres for bisphenol”, Journal of Membrane Science, 384, pp. 117–125, 2011[30]C. P. Azubuike, H. Rodríguez, and A. O.Okhamafe, “Physicochemical, spectroscopic and thermal
properties of microcrystalline cellulose derived from corn cobs”, International journal of recyclingof Organic Waste in Agriculture, Vol. 19, 425-433, 2012[31]G. Cleaver, “Unsaturated Polyester Resin on Agilent PL gel with Gel Permeation Chromatography”,
Materials Testing and Research, Polymers, Agilent Technologies, Inc., USA, 2015[32]N.L. Owen and D.W. Thomas, “Infrared studies of hard and soft woods, JournalofAppliedSpectroscopy ,43, 451–455, 1989.
[33] N.Kus, S. Breda, I. Reva , E. Tasal, C. OgretirandR.Fausto, “FTIR Spectroscopic and Theoretical
Study of the Photochemistry of Matrix-isolated Coumarin”,Journal of Photochemistry andPhotobiology, Vol. 83, pp. 1237-1253,2007.
[34] M.K.Subramaniam, P.M.Anbrasan and S.M.Animegalai,“Molecular structure, vibrational
spectroscopic studies and natural bond orbital analysis of Courmarin”, Journal of Physics, Vol. 74,
No.5, pp.845-860, 2010[35]J. Wu, K. Fukuzawa and J. Ohtani, “Lignin analysis in some tropical hardwoods using ultraviolet
microscopy”, Woodchemistry, Res. Bull. Coll. Exp.47, pp. 353–361,1990.
[36] F.W. Langkilde, and A. Skantesson, “Identification of celluloses with Fourier-transform (FT) midinfrared, FT-Raman and near-infrared spectroscopy”, Journal of Pharmaceutical and Biomedical
Analysis, Vol.13, pp. 409-415, 1995
[37]R.H. Marchessault, and C.Y. Liang, “Infrared spectra of crystalline polysaccharides.III. Mercerizedcellulose”, Journal of Polymer Science, Vol.43,No.141, pp. 71-84, 1960
[38]D. Fengel, “Characterization of Cellulose by Deconvoluting the OH Valency Range in FTIR
Spectra”, Holzforschung Journal, Vol.46, No.4, pp. 283-288, 1992[39] K.L.Tovar-Carrillo, M. Tagaya, and T.Kobayashi, “Bamboo Fibers Elaborating Cellulose
Hydrogel Films for Medical Applications”, Journal of Materials Science and Chemical
Engineering, Vol.1, pp. 7-12, 2013[40]P. K. AdapL, G. Schonenaua, Thomas Canam, and T. Dumonceaux, “Quantitative Analysis of
Lignocellulosic Components of Non-Treated and Steam Exploded Barley, Canola, Oat and Wheat
Straw Using Fourier Transform Infrared Spectroscopy”, Journal of Agricultural Science andTechnology, Vol. 1, pp.177-188, 2011[41]L.G. Xue, L. Tabil, and S. Panigrahi, "Chemical Treatments of Natural Fiber for Use in Natural
Fiber-Reinforced Composites”, Journal of Polymers and the Environment, Vol.15, No.1, pp. 25–
33, 2007[42] T. Nishino, I. Matsuda, and K. Hirao, “All-Cellulose Composites”, Macromolecules, Vol. 37,
No.20, pp. 7683-7687, 2004[43] M. C. García, M. C. Alfaro,N. Calero,and J. Muñoz, “ Influence of gellan gum concentration on
the dynamic viscoelasticity and transient flow of fluid gels”, Biochemical Engineering Journal ,Vol. 55, pp. 73, 2011
(Received: 7 October 2017, Accepted: 7 February 2018)8

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Palladium Ion Adsorbent of Fibrous Silk Fibroin Prepared from
Silkworm, Bombyx Mori

Tsukasa Sato, Tsugumi Seki, Saki Abe, Shinko Ito, Tatsuo Abe
Department of Creative Engineering, National Institute of Technology, Tsuruoka College,
104 Sawada, Inooka, Tsuruoka 997­8511, Japan*E­mail: tsato@tsuruoka­nct.ac.jp

Silk fibroin (SF) fiber in Tsuruoka, Japan was treated for palladium ion adsorbent.
The ability of adsorption of Pd2+ was highest among the ions of Cu2+ and Cs+ usedregardless pH condition. The addition of buffer salts decreased Cs+ adsoption, while
Pd2+ was independent of the salt addition. The absorbency of Cu2+ was changed
by pH condition, while the Cs+ adsorption was effectively disturbed by Na+ addedfrom the buffer salts. Fiber­type protein like SF fiber is promising as effective
adsorbent for Pd2+.

1. Introduction
The silk fibroin obtained from the silkworm, Bombyx mori, has been used as a textile fabric for along time. Recently, many kinds of investigations for their applications in various fields, such as
surgical sutures [1], food additives [2], cosmetics [3], drug­release materials [4, 5], and so on, havebeen extensively carried out. When such silk worm textile is applied for adsorption of metal ionsfrom aqueous solutions, a special interest is attractive for recovering metals and contributes onenvironmental problems. In commercial uses, zeolite and activated carbon have been used as such
adsorbent [6, 7]. However, because of their particle shape the handling and treatment are not easy tocondense and precipitate in solutions. The fiber shape like as silk makes easy to suspend them andtherefore becomes possible to adsorption more effectively in the solution. The natural silk fiber isconstituted of silk fibroin (SF) and a water­soluble protein glue, silk sericin (SS) (Fig. 1). It has beenreported that the silk protein has the capability to adsorb some metal ions on its specific chemical
structures [8­10]. The amino acid structure of the silk protein provides the ability to adsorb metal
ions at the amino (NH2) and carboxyl groups (COOH), since the terminals are present in the protein
macromolecule. Silk protein has in water isoelectric point (pH =3.7) and at over the pH region the NH2forms positively charged ammonium (NH3+). They can be thought that the carboxylate ionselectrostatically attract the metal ions in the acidic region. At higher the pH, the amino groups can becoordinated to metal ion(Fig. 1).
(a)

(b)

Silk fibroin（SF）
Silk sericin（SS）

Figure 1. The image of sectional view of raw silk (a), and adsorption mechanism of metal ions toterminals of the SF(b)1Transactions on GIGAKU 5(1)(2018)05005/1-6

It was known for SF fibers that the thermodynamic study about adsorption of Cu2+, Ni2+, Co2+, and
Mn2+ was reported [6-8]. But, there is no report palladium (Pd), which is known as the precious
metal and used as a material for fuel cells, catalysts and electrodes. This has been emphasizing theimportance of research of the process of recovering the precious metals from industrial waste.
Although in the some methods for Pd recovery, the sedimentation and the adsorption using activatedcarbon have been proposed, high selectivity and simple operatively are still required [11]. Therefore,
this paper describes adsorption of metal ions including Pd2+ on SF fiber shape, is expected that SF haslarge adsorption surface area and the solid-liquid separation after adsorption proceeds rapidly. In thisstudy, we investigated adsorption tendency in some metal ions, Pd2+, Cu2+, and cesium (Cs+) in the
aqueous solutions.
2. Experiment
2.1 Preparation of silk fibroin
The raw silk cocoons kindly supplied by MATUOKA Co., Inc. Japan were boiled with an aqueous
solution of 5 % Na2CO3 for 1 hour to remove SS, and then was in suction filtration to obtain SF (Fig.
2). The SF obtained was washed by distilled water and dried at 45 oC for more than 24 hrs under theatmosphere. The SF was immersed to the saturated CaCl2 aqueous solution. The solution of CaCl2
destroy aggregation of the SF fibers and increase surface areas. Then the SFs were rinsed by distilledwater to remove Ca2+ and Cl-, and then were dried. Thus, the fibrous SF was obtained. Analysis of
SF was operated by FTIR obtained using a Shimadzu IRAffinity-1 in the spectral region of 4000400cm-1. Sample of SF film was made by solution casting[12]. For the SF, the observed band at
3200cm-1 was due to N-H stretching vibration, and the bands appeared at 1650cm-1, 1540cm-1,
1235cm-1, and 650cm-1 are assigned, respectively, to amide I, amide II, amide III, and amide V for
random coil or silk I-form[13]. O-H stretching vibration was overwrapped with N-H stretching at
3100-3400cm-1.
(a)(b)

Figure 2 Appearance of silk cocoons (a) and SF fibers (b)2.2 Adsorption of each metal ion
The aqueous solutions of metal ion of 5-100 mg/L were prepared by diluting the original solutionsof PdCl2, Cu(NO3)2, and CsCl with a concentration of 1000 mg/L.

These solutions as an AAS(Atomic Absorption Spectrometry) grade were purchased from Kanto Chemicals Co., Inc. The 0.5
g of the SF prepared was added into 50 ml of the solution and then added 30 mL of the buffer solution
to adjust the pH. The buffer solution was prepared by mixing the 5 g of 0.1 M solution of acetic acidand 40.8 g of 0.6 M solution of sodium acetic acid(CH3COOH/CH3COONa). The value of pH wascontrolled at 6.9. The adsorption experiments were carried out under shaking for 3-480min in thewater bath controlled at 40 oC [8-10]. After that, SF was removed from the solution by filtration.
The concentrations of the ions of Pd2+ and Cu2+ in the aqueous solutions were measured by ICP
analysis (Inductively Coupled Plasma, Hitachi High-technologies SPS3500DD) and the Cs+ was AAS
analysis (Hitachi High-technologies Z-5010). Each adsorption experiment was carried out at least2

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three times and the average values of the concentrations were determined. The removal efficiency
can be calculated according to the following equation:
RE [%] =஼೔ ି஼೑

(1)஼೔

where RE is the removal efficiency of metal ions, Ci and Cf are the initial and the final concentrationsof metal ions (mg/L), respectively. In order to confirm existence of some kinds of elements on SF
surface, measurements using SEM-EDX (Hitachi FE-SEM S-4800 EDX) was employed.

3. Results and Discussion
3.1 Effects of contact time and initial concentration
First, effect of contact time on the adsorption efficiency was discussed for the SF fiber. Figure 3
shows effect of adsorption time on the removal efficiency for Pd2+, Cu2+ and Cs+. The initialconcentration was 50mg/L, for the buffer solution (CH3COOH/CH3COONa) added. As shown in
the figure, the value of RE for Cs+ and Cu2+ reached maximum at an early stage 3min. After that the
RE value somewhat decreased, implying the occurrence of desorption. From above result, we
assumed that the equilibrium was realized explained by two features of rate of adsorption andadsorption capacity, meaning that the capacity is determined by total amount of adsorption sites. On
the while the capacity is determined by total amount of adsorption sites. Shimidzu et al.
demonstrated that only 1/3 – 1/9 of carboxylate group was effective for adsorption[9, 10]. This is areason of less adsorption capacity of Cu2+ and Cs+. It was noted that Pd2+ was highly adsorbed to theSF fiber. The high absorbency for Pd2+ considered by formation of complex peculiar to metal­protein
structure at pH6.9[14].

Pd2+

Cu2+

Cs+

Figure 3. Effect of adsorption time on the removal efficiency for metal ions. The initialconcentration was 50 mg/L, and buffer solution was added.
3.2 Removal efficiency for each metal ion
The results of RE for each metal ion were shown at 120min (Figure 4). The figures (a) and (b)were compared with and without the buffer (CH3COOH/CH3COONa) added. The value for Pd2+
was the highest among the ions employed, while the RE of the Cs+ was 4 %, with the buffer at pH7.2,
i. e., the ion hardly adsorbs on the silk fibroin, but the value increased without the buffer. This meantthat that electrostatic force was acted in the adsorption. The tendency of removal efficiency was in
the order of Pd2+ ≫ Cu2+ ＞ Cs+. For Cu2+, the presence of the buffer was effective for theadsorption at pH 6.9 although the absence at pH 3.8 was significantly decreased. However, the3

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independence of the buffer addition was observed in the Pd2+ systems. It was interesting that thehigh adsorption was obtained at acidic region of pH 1.4. This meant that the coordination was stable
when the salt concentration was changed in the solution.
(a) with buffer solution(pH6.9)(b) without the buffer solution

100

RE(%)

pH1.4

50

pH7.2
pH3.8
0
CS(I)

Pd(II)Cu(II)

Figure 4. Results of removal efficiency of each metal ion with and without the buffer solution (aand b, respectively).
3.3 Effect of adsorption disturbance by Na+
In order to compare their adsorption behavior, the influence on RE for Pd2+ and Cs+ was measured
at different concentration of the sodium ion (Na+) which coexisted in the solution (Figure 5). The
value of the RE of the Pd2+ system was almost high value regardless change in the Na+ concentration,
while that of the Cs+ one decreased as the concentration of Na+ increased. This result suggests that
Na+ may disturb the adsorption of Cs+ on the SF adsorbent by electrostatic shielding effect. However,the Pd2+ ion could coordinate to the NH2 groups of the SF fiber without the disturbance with the salt
effect.

Figure 5. Effect of concentration for Na+ on the adsorption for cesium ions (initial concentration ofcesium ions: 50mg/L, without the buffer solution, time:120minutes)

SEM­EDX analysis was conducted in order to check the trace of the sodium which remains on SF
surface. The images obtained by SEM­EDX for SF after Cs+ adsorption are shown in Fig. 6.
4

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(A)
a

b

c

d

e

f

cps/eV
1.6
1.4
1.2

g

1.0
C

N

O

Na

Ca

0.8
0.6
0.4
0.2
0.0
0.20

0.40

0.60

0.80

keV

1.00

(B)
a

b

c

d

e

f

cps/eV
4.5
4.0
3.5

g

3.0
2.5

C
Ca

N

O

Na

2.0
1.5
1.0
0.5
0.0
0.20

0.40

0.60

keV

0.80

1.00

1.20

Figure 6. Results for SEM.EDX observations for SF after adsorption experiments of Cs+; (A)without the buffer solution, (B) with the buffer solution; (a) normal SEM image, (b) EDX image ofall detected atoms, and respective image for (c) carbon, (d) oxygen, (e)nitrogen, (f) sodium, (g)calcium.
In SEM image (a) of (A) and (B), smooth surface peculiar to SF fiber was confirmed. This was due
5Transactions on GIGAKU 5(1)(2018)05005/1-6

to result of eliminating sericin from the surface of raw silk. The diameter of the fiber was about 10
micrometers in general. The difference in the surface with or without of buffer solution system was
not observed. The detection result of carbon, calcium, nitrogen, and oxygen were also exhibited forcomparison. Existence of carbon, nitrogen, and oxygen is ordinary and is originated in silk protein.
The trace of the calcium used at the preparation of SF was not detected. The results of sodium
showed the distinctive situation by the existence of use of buffer solution. The peak whichcorresponds to Na in the sample exhibited without buffer solution was almost nothing. On the other
hand, the result of the silk using buffer solution showed large peak originating in the Na, suggesting
disturbing adsorption instead of Cs+. Although the EDX analysis by a SEM photograph was served
as observation on only surface of the sample, this was evidence that Na+ disturbed the adsorption of
Cs+ by ion exchange like a electrostatic shielding to the ionized protein groups.

4. Conclusion
The RE of Pd2+ was the highest among the ions used, because of suitable conditions of thecoordination adsorption. For Cu2+ adsorption, the buffer solution was effective to obtain suitable pH
condition and Na+ was adsorbed more preferentially than Cs+ by ion exchange. For Pd2+ recovery,
the SF fiber was promising as effective adsorbent.
Acknowledgments
The authors thanks to NIMS (National Institute for Materials Science) for helping SEM-EDX
measurements. This study was carried out by NIT-NUT (National Institute of Technology-Nagaoka
University of Technology) collaborative research promotion, Japan.
References[1] N. Minoura, M. Tsukata and M. Nagura, Biomaterials, 11, 430 (1990).
[2] T. Asakura, Bioindustry, 4, 878 (1987).
[3] K. Chen, K. Iura, R. Takano and K. Hirabayashi, J. Sericult Sci Jpn, 62, 56 (1992).
[4] M. Tsukada, G. Freddi, N. Minoura and G. Allara, J. Applie. Polym. Sci, 54, 507 (1994).
[5] S. Min, T. Nakamura, A. Teramoto and K. Abe, SEN-I GAKKAISHI, 54(5), 74 (1998).
[6] I. Yamagishi, J. Nuce., 18, 79(2011).
[7] H. Mimura, J. Ion exchange, 25, 45(2014).
[8] F. Shimidzu, K. Jyoko, I. Sakaguchi and T. Iijima, J. Fib. Sci. Tech., 32, (4), 166 (1976).
[9] F. Shimidzu and I. Sakaguchi, J. Fib. Sci. Tech., 35(8), 352 (1979).
[10] F. Shimidzu and I. Sakaguchi, J. Fib. Sci. Tech., 36(3), 127 (1980).
[11] Jacobsen RT, Chem. Eng. Prog., 101, 41(2005).
[12] T. Tanaka, T. Tanigami, K. Yamaura, Polymer International, 45, 175(1998).
[13 ] J. Magoshi, M. Mizuide,, Y. Magoshi, K. Takahashi, M. Kubo, and S. Nakamura, J. Polym.,
Polym. Phys. Ed., 17, 515(1979).
[14] Maruyama T. et al., Environ. Sci. Technol. 41, 1359(2007).
(Received: 13 October 2017, Accepted: 19 March 2018)6

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Numerical Study on Controlling Factors of Convection Behavior of
Hydrogen Generated in Radioactive Waste Long-term Storage
Containers
Yusei Tanaka1,*, Kazuyuki Takase1
Nagaoka University of Technology, Nagaoka, Japan 940-2188, s165048@stn.nagaokaut.ac.jp*E-mail: s165048@stn.nagaokaut.ac.jp

1)

Fuel debris which is removed from the Fukushima Dai-ichi Nuclear Power
Plant is packed to the inside of a radioactive waste long-term storage
container. When the fuel debris includes water, hydrogen and oxygen are
generated by decomposition of water by radiation from the fuel debris.
Since hydrogen is flammable gas, it has a risk of combustion or explosion.
Therefore, it is important to clarify the hydrogen behavior in the radioactive
waste long-term storage container. As for previous studies on hydrogen
behavior in the sealed container, experimental studies and analyses havebeen performed by several researchers. However, those studies onhydrogen behavior to various packing conditions of the fuel debris havenot been found. Then, controlling factors which define the convection
behavior of hydrogen were investigated numerically for various packed
conditions. The present study shows the predicted results on convection
behavior of hydrogen in a simply simulated radioactive waste long-term
storage container. The influence of the bulk density, inflow velocity,temperature, etc. upon the convection behavior of hydrogen was clarified
quantitatively.

1. Introduction
Fuel debris which is removed from the Fukushima Dai-ichi Nuclear Power Plant (1F) is packed tothe inside of a radioactive waste long-term storage container. When the fuel debris includes water,hydrogen and oxygen are generated by decomposition of water by radiation from the fuel debris. Sincehydrogen is flammable gas, it has a risk of combustion or explosion. Therefore, it is important toclarify the hydrogen behavior in the radioactive waste long-term storage container under the conditions
that the fuel debris containing water is accumulated. Moreover, the bulk density of the fuel debris is
not constant and the arrangement of that in the container is not uniform. That is, it is considered thatthe fuel debris accumulated in the container has arbitrary distributions in the vertical and horizontal
directions on the bulk density and the arrangement depending on the packing condition of the fueldebris into the container. However, it is not easy to clarify hydrogen behavior in the storage container
experimentally in terms of time and cost. Therefore, we conducted a study by numerical analysis.
As for studies of hydrogen behavior in the sealed container, Inoue, et al. [1] evaluatedexperimentally evaluating hydrogen diffusion using the Hallway model. On the other hand, Hoyes and
Ivings [2] performed CFD modelling of hydrogen stratification in enclosures and Visser, et al. [3]predicted numerically hydrogen distributions in a containment vessel. However, experimental andanalytical studies on hydrogen behavior to various packing conditions of the fuel debris have not beenfound. Then, the influence of the bulk density, inflow velocity, temperature, etc. upon the convection
behavior of hydrogen was analyzed numerically.
The present study shows the predicted results on convection behavior of hydrogen in a simply
simulated radioactive waste long-term storage container. Controlling factors which define theconvection behavior of hydrogen are described in detail.
2. Numerical Analysis
1Transactions on GIGAKU 5(1)(2018)05006/1-8

2.1 Basic equations
For the analysis, The ANSYS FLUENT [4-5] was used. The basic equations on thermal-hydraulicsof the multi-component gases considering compressibility are as follows.
‑ Mass conservation equation߲‫݌‬߲+൫ߩ‫ݑ‬௝ ൯ = 0 (1)߲‫ݔ߲ ݐ‬௝‑ Momentum conservation equation
߲
߲
߲‫݌‬
߲
߲‫ݑ‬௜ ߲‫ݑ‬௝(ߩ‫ݑ‬௜ ) +൫ߩ‫ݑ‬௜ ‫ݑ‬௝ ൯ = −+ቈߤ ቆ+
ቇ቉ + ߩ݃௜
(2)
߲‫ݐ‬
߲‫ݔ‬௝
߲‫ݔ‬௜ ߲‫ݔ‬௝߲‫ݔ‬௝ ߲‫ݔ‬௜‑ Energy equation
߲
߲‫݌‬
߲ܻ௦
߲
߲‫݌‬
߲
߲ܶ
߲
(ߩℎ) +
൱+ܳ(3)൫ߩℎ‫ݑ‬௝ ൯ =+ ‫ݑ‬௝+ቆߣቇ+൭ߩ ෍ ℎ௦ ‫ܦ‬௦߲‫ݐ‬߲‫ݔ‬௝ ߲‫ݔ‬௝ ߲‫ݔ‬௝
߲‫ݔ‬௝
߲‫ݔ‬௝
߲‫ݐ‬
߲‫ݔ‬௝
௦

‑

Mass conservation equation of species
߲ܻ௦
߲
߲
߲
(ߩܻ௦ ) +൫ߩܻ௦ ‫ݑ‬௝ ൯ =ቆߩ‫ܦ‬௦
ቇ
(4)
߲‫ݔ‬௝
߲‫ݐ‬
߲‫ݔ‬௝
߲‫ݔ‬௝
‑ Equation of stateܴ଴‫݌‬௦ = ߩ௦
ܶ
(5)
‫ܯ‬௦
The density r, pressure p, enthalpy h and mass fraction Ys and in the above basic equations are defined
as follows.
‫ = ݌‬෍ ‫݌‬௦௦ℎ = ෍ ܻ௦ ℎ௦
௦

ܻ௦ =

ߩ௦
ߩ

(6)

(7)

(8)

2.2 Porous model
In the porous media model, an empirically determined ﬂow resistance is used to the region
deﬁned as “porous” [5]. Porous media are modeled by the addition of a momentum source term to
the standard ﬂuid ﬂow equations. The source term is composed of two parts; a viscous loss term andan inertial loss term.
ଷ

ଷ

௝ୀଵ

௝ୀଵ

1
‫ݏ‬௜ = − ቌ෍ ‫ܦ‬௜௝ ߤߥ௝ + ෍ ‫ܥ‬௜௝ ߩ|ߥ|ߥ௝ ቍ
2(9)where Si is the source term for the i-th (x, y, or z) momentum equation, |v| is the magnitude of thevelocity and D and C are prescribed matrices.
In the present study the porous media is assumed as homogeneous and the following equation isderived.
ଷߤ1ܵ௜ = − ቌ ߥ௜ + ෍ ‫ܥ‬ଶ ߩ|ߥ|ߥ௝ ቍ
2
ߙ
௝ୀଵ

(10)

where α is the permeability and C2 is the inertial resistance factor. From the assumption of packed
beds, those values are shown as
‫ܦ‬௣ଶ
ߝଷ
α=
(11)
150 (1 − ߝ)ଶ
3.5 (1 − ߝ)‫ܥ‬ଶ =(12)‫ܦ‬௣ ߝ ଷ
The scheme of solution method uses the SIMPLE (Semi-Implicit Method for Pressure-Linked
Equation) method. In order to analyze transport behavior of two component gases between air and2

Transactions on GIGAKU 5(1)(2018)05006/1-8hydrogen, the mixture model was chosen. The fluid in the container is set to be mixture of air andhydrogen. At the initial condition, the inside of the container is filled air completely and hydrogen isnothing.
3. Analytical Conditions
3.1 Computational grid
Figure 1 shows the computational grid used in this calculation. The radioactive waste storage
container is simulated with a sealed two­dimensional rectangular container. Here, fuel debris issimulated by ‘Porous model’. In this calculation, a packed bed model which is one of the ‘Porous
model’ is used. In the packed bed model, it is expressed by inertial resistance and viscous resistancewhich can be obtained by Eq. (11) and (12). The resistances of Eq. (11) and (12) are determined by
the porosity and the particle diameter. The heat of decay is simulated by giving heat to the porous zone.
The generation of hydrogen is simulated by flowing from the nozzle which is positioned at the bottomof the container. The dimensions of the container are the same as the experimental setup which isshown Fig.2. The computational grid is set to 45 × 90 cells, and adopted a non­uniform mesh division
which makes a finer mesh at the vicinity of the wall.
As an outline of this calculation, the container is filled with air initially, the lower half of thecontainer is set to the porous, and hydrogen is flowed from one of the three nozzles at the bottom of
the container. The heat transfer rate is given to the porous media. In this calculation, only one
positioned nozzles at the center are used.

Fig.1 Computational gridFig.2 Experimental set up

3.2 Calculation Parameters
Table 1 shows the controlling factors which specify to influence the hydrogen behavior. On thecontrolling factors, the hydrogen generation amount, the decay heat amount, and the bulk density offuel debris are considered. In order to investigate numerically the effect of these controlling factor,
parameters of the initial flow rate of hydrogen, the heating amount, and the porous packing density
are used.
As for a method of estimating hydrogen generation amount and decay heat amount, the decay heatamount was calculated using the TODRES equation [6­8]. The equation of TODRES is shown inequation (13).
ܲ(‫)ݐ‬= 0.066[‫ି ݐ‬଴.ଶ − (‫ݐ‬௦ + ‫ି)ݐ‬଴.ଶ ] (13)ܲ଴Where P is the decay heat, ܲ଴ is the thermal output during normal operation of the reactor, ‫ ݐ‬is theelapsed time since reactor shutdown, ‫ݐ‬௦ is the time of fuel rod use, ܲ଴ is given 1380 MW from thedata of 1F [8­9], and ‫ݐ‬௦ is given 1.74 years from reference [8­10]. The calculation results are shownin Fig. 3. The horizontal axis in Fig. 3 is the elapsed time after reactor shutdown, and the vertical axis
is the ratio of decay heat to normal output. Subsequently, on the assumption that debris is packed in
the inside of the container entirely, the decay heat quantity is obtained using the volume of the3

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container, which is calculation by Eq. (14).

ܲ×ܸ
(14)
9.924
Where ܲ′ is the decay heat in the container and V is the volume of the container, and the value of
9.924 is the volume of all the fuel rods in 1F. The calculation result is shown in Fig.4. The horizontal
axis of Fig. 4 shows the elapsed time from the reactor shutdown, and the vertical axis shows the decay
heat amount.
In addition, the hydrogen generation amount was estimated from the decay heat amount and thehydrogen generation value (G value). The G value was 4.7 × 10 -8 mol/J from the reference of [11] and[12]. The calculation result is shown in Fig.5. The horizontal axis of Fig. 5 is the heating transfer rate,
and the vertical axis is the initial flow velocity calculated in consideration of the hydrogen generation
amount and the cross-sectional area of the nozzle from the hydrogen generation amount.
Calculation matrix was prepared from calculation of hydrogen generation amount and decay heatamount. The calculation matrix is shown in Table 2. Here, the inlet velocity of 0.4 m/s means thehydrogen flow rate which is generation in a container after one month from the shutdown of the reactor
core. Similarly, the inlet velocity of 0.1 and 0.4 m/s mean average hydrogen flow rate in a container
after 1 year and 10 years from the shutdown of the reactor core. For setting of porosity and particle
diameter. In the calculation, the particle diameter was fixed to 10 mm, porosity was set to 0.2 (statewith many substance), 0.5 (middle), and 0.8 (state with many space).
ܲ′ =Table.1 Estimated controlling factors
Analysis time conditions
Inlet velocity
Hydrogen generation amount& Inflow time
Heating transfer rate
Decay heat(Source term)
Packed bed modelDensity of the fuel debris(Porosity and particle diameter)

Estimated parameters

Controlling factors

Temperature
Friction loss

1×106
1.E+06decay heat [W]

1×10-2
1.E-02

1×10-4
1.E-04

1.E+03
1.E+06
1×103
1×106
elapsed time (s)1.E+04
1×104
1×102
1.E+02
1×100
1.E+00
1.E+00
1×100

1.E+091×109

1.E+03
1×103

1.E+06
1×106

1.E+091×109

elasped time [s]Fig.3 TODRES equation

Fig.4 Decay heat estimation

1×106
1.E+062

1×104
1.E+041
1.E+02
1×102

1×100
1.E+00
1.E+02
1×102

0
1.E+04
1×104

1.E+06
1×106

heating transfer rate (W)4

inlet verocity (m/s)

1.E-06
1×10-6
1.E+00
1×100

H2 generation rate (L/day)

P/P0

H2 mole concentration

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Fig.5 Hydrogen generation rate estimation
Table.2 Calculation matrix
Inlet velocity [m/s]Heating amount (W)
0.01
0.1
0.4
830
7600
31000
4. Preliminary calculation result
4.1 Velocity
Preliminary analysis was carried out based on the calculation conditions shown in Table 2. First,
the results on the difference in inlet velocity are shown. The analysis was performed by the non­steadystate, the calculation time was 10 seconds. The inlet flow velocity of hydrogen is changed, heating
amount and porosity are constant, which are 7600W and 0.5, respectively. Figure 6 shows the H2 molar
concentration distribution at inlet velocities of 0.1 m/s and 0.4 m/s. As compared with 0.1 m/s, 0.4 m/sshows that diffusion of hydrogen is observed in the upper region of the container, and the concentration
is higher. Next, the relationship between the inlet velocity and molar concentration is shown in Fig.7.
The horizontal axis in Fig. 7 is the inlet velocity, and the vertical axis is the maximum molar
concentration in the porous region and the non­porous region. At 0.01 m/s it was confirmed that theconcentration is low even in the porous region, and at 1 m/s, it has high concentration even in the non­porous region.

MOLE
CONCENTRATION(KMOL/M3)

0.05

porousnon-porous

0.04
0.03
0.02
0.01
0
0.01

Fig.6 Contour of mole concentration

0.1
INLET VELOCITY (M/S)

1

Fig.7 Graph of mole concentration

4.2 Heating amount rate
The calculation was performed up to 300 s to investigate the effect on heating amount. The heating
amount is changed, inlet flow velocity of hydrogen and porosity are constant, which are 0.1m/s and
0.5, respectively. The temperature distribution of 7600 W and 31000 W is shown in Fig.8. The change
in temperature was 4 K for 7600 W and 8 K for 31000 W. Next, the relationship between heating
amount and temperature is shown in Fig.9. The horizontal axis in Fig.9 is the heating amount, and thevertical axis is the temperature difference ΔT at the center positions between the porous region andthe non­porous region. From Fig.9, it was confirmed that the temperature of both the porous region
and the nonporous region rises logarithmically.

5

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porousΔT

100

non-porous

10
1
0.1
1.E+03 3

1.E+04 4

1×10

1×10

1.E+055

1×10

1.E+066

1×10

HEATING TRANSFER RATE (W)Fig.8 Contour of temperature

Fig.9 Graph of temperature

4.3 Porosity
The calculation was performed up to 10 s to investigate the effect on porosity. The porosity
changed, inlet flow velocity of hydrogen and heating amount are constant, which are 0.1m/s and 0.5,
respectively. The difference in Porosity in the packed bed model is represented by the difference
between inertial resistance and viscous resistance. In this calculation, the particle size was fixed at 10mm in order to investigate the effect of Porosity. The flow velocity distributions with the Porosity of
0.4 and 0.8 are shown in Fig.10. When the porosity is 0.4, it flows straight ahead, and when the porosity
is 0.8, we see that the diffusion has started. Next, the relationship between Inertial resistance (C2)derived by Eq. (12) and porosity is shown in Fig.11. The horizontal axis is porosity, and the verticalaxis is inertial resistance. The higher the porosity, the higher the inertia resistance and the smaller theparticle diameter, the higher the inertia resistance. The difference in resistance between the particle
diameter of 10 and 100 mm is around 102 for a unit length.

inertial resistance (C2)

10mm

30mm

1×1012
1.E+12

50mm

100mm

102

1.E+101×108
1.E+081.E+06
1.E+04
1×104
1.E+02
1×100
1.E+000.01

Fig.10 Contour of velocity

0.1
porosity1

Fig.11 Graph of inertial resistance

5. Conclusions
In this research, preliminary analysis was conducted on the hydrogen behavior in the radioactive
waste storage container associated with the decommissioning reactor of 1F. The influence of thecontrolling factors were analyzed by numerical analysis. As the present results, the following
conclusion was derived.
1) As for the influence of the inlet velocity of hydrogen, the molar concentration distribution ofhydrogen changes and the time required to pass through the porous region varies.
2) In the influence of heating amount, there is little influence on hydrogen behavior without heat ortime above a certain level. In both the non­porous region and the porous region, the temperature
increases logarithmically.
3) In the influence by porosity, porosity has changed its resistance to flow, and the velocity
distribution in the porous region changes greatly and the time required to pass through the porous
region varies.
In the future, we will analyze for a long time, and we will clarify the influence due to particle diameter,6Transactions on GIGAKU 5(1)(2018)05006/1-8

and buoyancy effect due to the heat transfer rate by the decay heat.
Nomenclature‫ܥ‬ଶ the inertial resistance factor [1/m]‫ܦ‬௣ mean particle diameter [m]‫ܦ‬௦ effective diffusion coefficient of chemical species s [m2/s]
ggravity [m/s2]henthalpy [J/kg]
hs
enthalpy of chemical species s [J/kg]
Ms Molecular weight · atomic weight of chemical species s [kg/mol]ܲ
decay heat [W]ܲ଴thermal output during normal operation of the reactor [W]ܲ′ decay heat amount in the volume of the container [W]p pressure [Pa]ps partial pressure of chemical species s [Pa]Q calorific value [W/m3]
R0 universal gas constant (= 8.314) [J/mol/K]
T temperature [K]‫ݐ‬
elapsed time from reactor shutdown [s]‫ݐ‬௦fuel rod use time [s]uvelocity [m/s]Vvolume [m3]x descartes coordinates [m]Ys mass fraction of chemical species s [-]ߙpermeability [m2]߳porosity [-]λ heat conduction coefficient [W/m/K]
μ viscosity [Pa·s]ν kinetic viscosity [m2/s]
ρ density [kg/m3]
ρsdensity of chemical species s [kg/m3]
Subscriptsi
x direction lattice indexjy direction lattice index
Acknowledgments
A part of this study is the result of “ Research and development on technology for reducing theconcentration of flammable gases generated in waste long-term storage containers ” carried out under
the Center of World Intelligence Project for Nuclear S&T and Human Resource Development by the
Ministry of Education, Culture, Sports, Science and Technology of Japan.
References[1] M. Inoue, H. Tsukikawa, H. Kanayama, K. Matsuura, Experimental Study on Leaking Hydrogen
Dispersion in a Partially Open Space, Hydrogen energy system, Vol.33, No.4, pp32-43, (2008)[2] J.R. Hoyes, M.J. Ivings, CFD modelling of hydrogen stratification in enclosures: Model validation
and application to PAR performance, Nuclear Engineering and Design 310, pp142-153, (2016)[3] D.C. Visser, M. Houkema, N.B. Siccama, E.M.J. Komen, Validation of a FLUENT CFD modelfor hydrogen distribution in a containment, Nuclear Engineering and Design 245, pp161-171,(2012)[4] ANSYS, Inc., ANSYS FLUENT User’s Guide, (2009)[5] ANSYS, Inc., ANSYS FLUENT Theory Guide, (2009)7

Transactions on GIGAKU 5(1)(2018)05006/1-8[6] Neil E. Todreas and Mujid S. Kazimi, Nuclear Systems I, Thermal Hydraulic Fundamentals,
Hemisphere Publishing Corporation, (1990)[7] McMaster Nuclear Reactor, McMaster University, “Decay Heat Estimates for MNR”, Technical
Report 1998-03, http://www.nuceng.ca/papers/decayhe1b.pdf[8] Tohoku University Institute of Fluid Sciences Yuyama · Komiya Lab., Estimation of the amountof water required when the interior of the nuclear reactor is heated only by decay heat, HeatTransfer Control Lab. Report No. 1, Ver. 4 , (2011)[9] TEPCO, "Outline of Fukushima Daiichi Nuclear Power Station facility",
http://www.tepco.co.jp/nu/fukushima-np/outline_f1/index-j.html[10] TEPCO, "Periodical Inspection Result",
http://www.tepco.co.jp/nu/f1np/data_lib/pdfdata/bk1011-j.pdf．
[11] Tomoyasu Kumagai Japan Atomic Energy Agency, Radiolysis of water and treatment ofradioactive contaminated water with zeolite, The 46th Japan Atomic Energy Society Award
Encouragement Prize[12] Buxton, G.V. The radiation chemistry of liquid water: principles and applications. In:
Mozumder, A., Hatano, Y. (Eds.), Charged Particle and Photon Interactions with Matter. Marcel
Dekker, Inc., New York, (2004)(Received: 23 October 2017, Accepted: 12 January 2018)8