bluuebunny/crossref_metadata_2025 huggingface dataset:
Depth-resolved X-ray residual stress analysis in PVD (Ti, Cr) N hard coatings
Authors: Genzel Christoph , Reimers Walter
Published: February 2022

Physical vapour deposition (PVD) of thin hard coatings on TiN basis is usually performed at rather low temperatures (TD< 500 °C) far from thermal equilibrium, which leads to high intrinsic residual stresses in the growing film. In contrast to the extrinsic thermal residual stresses which can easily be estimated from the difference of the coefficients of thermal expansion between the substrate and the coating, a theoretical prediction of the intrinsic residual stresses is difficult, because their amount as well as their distribution within the film depend in a very complex way on the deposition kinetics. By the example of strongly fibre-textured PVD (Ti, Cr)N coatings which have been prepared under defined variation of the deposition parameters in order to adjust the residual stress distribution within the coatings, the paper compares different X-ray diffraction techniques with respect to their applicability for detecting residual stresses which are non-uniform over the coating thickness.
Characterization of thermal and anodic oxide layers on β- and on near-β-titanium alloys for biomedical application
Authors: Velten D. , Schenk-Meuser K. , Biehl V. , Duschner H. , Breme J.
Published: February 2022

β- and near-β-Ti alloys for biomedical applications show a favourable mix of mechanical, biological and biocompatible properties. In this study, oxide layers on Ti13Nb13Zr, Ti15Mo5Zr3Al, Ti30Nb and Ti30Ta were prepared by thermal and anodic oxidation, in order to adjust constant, reproducible and well-defined surface properties. The thickness, the phase composition and the element composition of the oxide layers were determined. The corrosion properties were investigated by current density –potential curves under physiological conditions. Depending on the oxidation parameters, film thicknesses in the range 10 – 250 nm can be prepared. The thermal oxide layers consist predominantly of TiO2 in rutile structure while the anodized samples show a mixture of anatase and amorphous TiO2. In addition, certain amounts of mixed oxides of titanium and alloying elements such as TiZrO4 or TiNb2O7 are found in the oxide films. The corrosion resistance of the oxidized samples is increased as compared with the polished samples whose current densities in the range of passivity are comparable to that of Ti6Al4V.
Micromechanisms and modelling of crack initiation and growth in tool steels: role of primary carbides
Authors: Mishnaevsky Leon L. , Lippmann Nils , Schmauder Siegfried
Published: February 2022

Micromechanisms of damage initiation and crack growth in high speed and cold work steels are investigated using scanning electron microscopyin situexperiments. The role of primary carbides in initiation and growth of cracks in tool steels is clarified. It is shown that initial microcracks in the steels are formed in primary carbides and then join together. A hierarchical finite element model of damage initiation, which included a macroscopic model of the deformation of the specimen under real experimental conditions and a mesomechanical model of damage in real microstructures of steels, was developed. Using the hierarchical model, the conditions of local failure in the steels have been obtained. In order to study the effect of carbide arrangement on fracture, numerical simulations of fracture in steels with different ideal carbide arrangements were carried out and compared with each other. It is found that the heterogeneous arrangements of primary carbides can lead to strong deviations of a crack from the mode I path and, therefore, to a significant increase of the fracture energy of the steels.
Dislocation microstructures of single crystal ⟨001⟩ CMSX-4 specimens tensile tested at 700 and 1000°C
Authors: Schubert Florian , Penkalla Heinz-Josef , Singheiser Lorenz
Published: February 2022

Two principal methods are used to derive constitutive equations for single crystal Ni-base superalloys: development of a creep potential according the Hill’s theory and the summarization of all activated slip systems: theoretically, the octahedral and the cubic slip system must be considered. An overview of dislocation structure evolution has been performed using transmission electron microscopy (TEM) techniques on 〈001〉-orientated CMSX-4 specimens after tensile tests. The aim of the applied conventional TEM methods was to provide with more details about the influence of temperature and deformation rate on the deformation behaviour of CMSX-4 nickel-base single crystal. A correlation of the γ' phase deformation mechanisms and associated mechanical responses for different tensile testing conditions has been done. With TEM methods the dislocation dipole identification as well as the stacking fault nature has been demonstrated.
Influence of mechanical surface treatments on the HCF performance of the Ni-superalloy Udimet 720 LI
Authors: Lindemann Janny , Grossmann Kim , Wagner Lothar
Published: February 2022

Shot peening was performed on smooth (geometrical notch factor k
t = 1.0) and circumferentially notched (k
t = 2.3 and 3.5) specimens. In addition, some notched (k
t = 3.5) specimens were deep rolled. Axial fatigue tests were done at room temperature and 650 °C using a stress ratio of R = 0.1. At ambient temperature, shot peening markedly increased the high-cycle fatigue (HCF) strengths at R = 0.1 of smooth and, particularly, notched specimens with respect to the electropolished reference samples. In contrast, shot peening was found to decrease the HCF strength of smooth samples at elevated temperature (650 °C) while the HCF strength of notched specimens was slightly increased. Best elevated-temperature HCF strength of notched conditions was observed after deep rolling.
Precipitation of β-phase and twinning during deformation of Mg–Al alloy AZ91 at 150 °C after solution treatment
Authors: Zhang Ping , Blum Wolfgang
Published: February 2022

Precipitation of β-phase and deformation twinning have been studied in a solid solution-treated AZ91 alloy, which was subjected to compressive creep loading at 150 °C and 100 MPa for 163 h. It was found that nucleation of β-phase in solution-treated AZ91 is enhanced by concurrent deformation under creep conditions at 150 °C. The relatively fine precipitate structure leads to a reduction in minimum creep rate and, therefore, to an increase in creep life by a factor of 10 compared to the as-cast condition at the investigated conditions. In addition, twinning occurred in coarse grains of hard orientation. The twin boundaries lead to formation of incoherent precipitates and discontinuous precipitation within the former grains.
Nanograin size, high-nitrogen austenitic stainless steels
Authors: Speidel Markus O.
Published: February 2022

A new class of high-strength steels has been developed by combining solid solution hardening and grain boundary hardening in high-nitrogen austenitic stainless steels. Average grain diameters from 50 to 250 nm can be achieved, and yield strength levels of more than 2000 MPa in the solution-annealed condition have been measured. The effect of nitrogen solid solution hardening and grain boundary hardening is systematically explored.
Strength and ductility of thin Cu wires
Authors: Khatibi Golta , Stickler Roland , Weiss Brigitte
Published: February 2022

The stress– strain behavior of thin copper wires in the range 20 – 250 μm diameter and various purities (3N, 5N) have been investigated. The wires were subjected to a recrystallization heat treatment and tensile properties were determined. Tensile testing was performed using a microtensile testing machine equipped with a non-contacting laser-optical speckle correlation sensor adapted for high-resolution strain measurement. The fracture elongation of all specimens exhibited lower values than that of bulk Cu with a decreasing trend for thinner wires. High-purity wires with a pronounced bamboo structure showed a size dependence of the yield strength which increased with decreasing wire diameter. Surface topography and fracture surfaces of the specimens were examined. The microstructural investigations were performed to arrive at an understanding and interpretation of our experimental results.
Phase diagram of the Al–Cu–Fe quasicrystal-forming alloy system
Authors: Zhang Liming , Lück Reinhard
Published: February 2022

The microstructures of as-cast and slowly solidified Al– Cu–Fe ternary alloys in the vicinity of the icosahedral phase region have been investigated using light microscopy and scanning electron microscopy. The chemical composition of the different phases present has been determined by energy-dispersive X-ray spectroscopy with a correction of electron probe microscopy analysis. The solidification process was studied by means of the differential thermal analysis and magnetothermal analysis measurements. In contrast to the equilibrium phase diagram, fast cooling leads to the formation of a metastable β′ phase (an ordered cubic structure) rather than to the formation of the φ phase. The nucleation of ω phase is very sluggish during the solidification. The results are presented as solidification paths, superimposed onto the liquidus surface projection to demonstrate the solidification sequences.
Effect of Sr on the microstructure and corrosion properties of the as-cast Mg–Zn–Zr alloy
Authors: Wu Jinxiang , Cao Xin , Xu Chunxiang , Dong Yuxing , Di Xinming , Zhang Jinshan
Published: February 2022

The effect of Sr on the microstructure of Mg–Zn–Zr alloys was investigated by means of scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. An immersion experiment and electrochemical experiment were designed to study the effect of Sr on the corrosion performance of the alloys. The results show that the addition of Sr promotes the formation of Mg17Sr2 phase in the alloy, and this stripe phase appears at the alloy grain boundaries. With the increase in Sr content, a network structure is formed at the grain boundary, creating a corrosion barrier to prevent further corrosion of the alloy. The study found that Mg-4Zn-0.4Zr-1.0Sr alloy has the best corrosion performance.
Privacy-preserving Web single sign-on: Formal security analysis and design
Authors: Schmitz Guido
Published: February 2022

Single sign-on (SSO) systems, such as OpenID and OAuth, allow Web sites to delegate user authentication to third parties, such as Facebook or Google. These systems provide a convenient mechanism for users to log in and ease the burden of user authentication for Web sites. Conversely, by integrating such SSO systems, they become a crucial part of the security of the modern Web.

So far, it has been hard to prove if Web standards and protocols actually meet their security goals. SSO systems, in particular, need to satisfy strong security and privacy properties. In this thesis, we develop a new systematic approach to rigorously and formally analyze and verify such strong properties with the Web Infrastructure Model (WIM), the most comprehensive model of the Web infrastructure to date.

Our analyses reveal severe vulnerabilities in SSO systems that lead to critical attacks against their security and privacy. We propose fixes and formally verify that our proposals are sufficient to establish security. Our analyses, however, also show that even Mozilla’s proposal for a privacy-preserving SSO system does not meet its unique privacy goal. To fill this gap, we use our novel approach to develop a new SSO system, SPRESSO, and formally prove that our system indeed enjoys strong security and privacy properties.
Certain Estimates of Normalized Analytic Functions
Authors: Anand Swati , Jain Naveen Kumar , Kumar Sushil
Published: February 2022

Let ϕ be a normalized convex function defined on open unit disk

D

. For a unified class of normalized analytic functions which satisfy the second order differential subordination f′(z) + αzf″(z) ≺ ϕ(z) for all

z
∈
D

, we investigate the distortion theorem and growth theorem. Further, the bounds on initial logarithmic coefficients, inverse coefficient and the second Hankel determinant involving the inverse coefficients are examined.
Approximation Properties of λ-Bernstein-Kantorovich-Stancu Operators
Authors: Bodur Murat , Manav Nesibe , Tasdelen Fatma
Published: February 2022

The goal of this paper is to construct a new type of Bernstein operators depending on the shape parameter λ ∈ [–1,1]. For these new type operators a uniform convergence result is presented. Furthermore, order of approximation in the sense of local approximation is investigated and Voronovskaja type theorem is proved. Lastly, some graphical results are given to show the rate of convergence of constructed operators to a given function f.
Some Characterizations of Mixed Renewal Processes
Authors: Lyberopoulos Demetrios P. , Macheras Nikolaos D.
Published: February 2022

Some characterizations of mixed renewal processes in terms of exchangeability and of different types of regular conditional probabilities are given. As a consequence, an existence result for mixed renewal processes, providing also a new construction for them, is obtained. As an application, some concrete examples of constructing such processes are presented and the corresponding regular conditional probabilities are explicitly computed.
On Mahler's Classification of Formal Power Series Over a Finite Field
Authors: Kekeç Gülcan
Published: February 2022

Let K be a finite field, K(x) be the field of rational functions in x over K and

K

be the field of formal power series over K. We show that under certain conditions integral combinations with algebraic formal power series coefficients of a U
1-number in

K

are Um
-numbers in

K

, where m is the degree of the algebraic extension of K(x), determined by these algebraic formal power series coefficients.
Numerical and experimental formability analysis of aluminum 3105 sandwich panels produced by continuous hot-press forming
Authors: Elibol Cagatay , Wapande Sadam Hamis
Published: February 2022

Aluminum–plastic composites as building materials are widely used for different construction purposes, for instance, for exterior wall cladding, ventilated facades, and interior decoration of buildings, in billboards, trains, and automotive industry. The main goal of this study is to investigate the formability of AA3105/LDPE/AA3105 sandwich composite in detail, which would exhibit a higher formability compared to AA3105 due to its higher strain rate sensitivity and strain hardening exponent. This is of decisive importance for the manufacturing process. The Nakajima tests are performed to experimentally determine the forming limit curves (FLCs) usingin situoptical technique digital image correlation. Furthermore, numerical simulations of Nakajima tests are conducted using a modified Gurson–Tvergaard–Needleman damage model to compare the numerically and experimentally determined FLCs. The results show that the sandwich composite underwent inhomogeneous deformation during the Nakajima test, and that the FLC has no typical patterns exhibited by metal sheets. The FLCs predicted by the numerical model used in this study exhibit a very good correlation with the FLCs determined experimentally. The results of the present study provide new insights into the analysis and understanding of the deformation behavior of the sandwich composite sheet that may undergo complex stress and strain states.
Characterization of Fe2B layers on ASTM A1011 steel and modeling of boron diffusion
Authors: Morgado-González Irving , Ortiz-Dominguez Martin , Keddam Mourad
Published: February 2022

In this work, the ASTM A1011 steel substrate has been pack-boronized in the interval of 1123–1273 K for 2–8 h. With the used powders mixture (33.5 wt.% B4C, 5.4 wt.% KBF4 and 61.1 wt.% SiC), the iron boride layers were formed on this steel. The boronized layer/matrix was characterized by a jagged morphology. X-ray diffraction technique was used in order to identify the presence of iron boride phase. Tribological studies were also undertaken to assess the interfacial adherence of boride layer to the substrate and the values of coefficient of friction (COF) for borided and unborided samples. In addition, the mean diffusion coefficient approach was employed to estimate the diffusivity of boron in Fe2B. Moreover, this diffusion model has been verified empirically by using an extra boriding condition (at 1248 K for 2 h).
Effect of heat treatment on microstructure and properties of modified hypereutectic high chromium cast iron
Authors: Chen Zhengyang , Guo Qiang , Fu Hanguang , Zhi Xiaohui
Published: February 2022

The effect of heat treatment on the microstructure, hardness and wear resistance of modified hypereutectic high chromium cast iron (HCCI) was investigated. The results show that the quenching treatment partially dissolves the edges of the primary carbides, and the sharp corners become rounded and blunt. As the quenching temperature increases, the carbide re-dissolves into the matrix, and the hardness and wear resistance first increase and then decrease. The hardness and wear resistance are the best when quenched at 1000 °C. After tempering, the martensite is transformed into tempered martensite, and the precipitation of secondary carbides increases. As the tempering temperature increases, the secondary carbides gradually become coarser. When the tempering temperature is 500 °C, the hypereutectic HCCI shows the highest hardness and the best wear resistance. When tempered at 400 °C, hypereutectic HCCI shows the best erosion and wear resistance.
Crystal structure of trans-1,2-bis(pyridinium-4-yl) ethylene bis(2-carboxy-4-bromobenzoate) – water (1/4), C14H14BrNO6
Authors: Wei-Wei Yuan
Published: February 2022

C14H14BrNO6, triclinic, P

1
‾

$\overline{1}$

(no. 2), a = 6.9693(3) Å, b = 8.6514(5) Å, c = 13.6726(8) Å, α = 72.774(5)°, β = 81.547(4)°, γ = 74.370(4)°, V = 756.26(7) Å3, Z = 2, R

gt
(F) = 0.0341, wR

ref
(F
2) = 0.0689, T = 290.7(3) K.
Application of carboxymethyl cellulose-acrylate-OVPSS graft copolymer emulsion in paper reinforcement and protection
Authors: Zhang Jin-Jie , Qi Ying-Ping , Shen Yong-Feng , Li Hua
Published: February 2022

Paper cultural relics are both precious, inheritable and fragile. However, with the passage of time, paper will also be affected by a variety of factors, and will appear mildew, yellow, brittle, or even completely damaged. In order to protect the cultural relics, extend lifespan paper, CMC-acrylate-OVPOSS graft copolymerization emulsion was synthesized by using carboxymethyl cellulose (CMC) as substrate, methyl methacrylate (MMA), butyl acrylate (BA), glycidyl methacrylate (GMA), hydroxyethyl methacrylate (HEMA), octavinyl polyhedral oligomeric silsesquioxane (OVPOSS) as graft copolymer. The CMC-acrylate-OVPOSS emulsion was coated on the surface of the paper to test its protective effect on the paper. The results showed that the mass concentration of 10 % reinforcement solution coated on the paper, mechanical properties of paper were greatly improved, and the gloss and whiteness of paper were slightly changed, the paper also had a certain aging resistance and acid and alkali corrosion resistance. At the same time, the reversibility experiment showed that the reinforcement material had a certain reversibility.
Ginsenoside-Mc1 reduces ischemia/reperfusion-induced cardiac arrhythmias through activating JAK2/STAT3 pathway and attenuating oxidative/endoplasmic reticulum stress in hyperlipidemic rats
Authors: Zhang Yanwei , Xu Kun , Zhang Yanqing
Published: February 2022

Objectives

Patients suffering from myocardial ischemia-reperfusion (IR) injuries usually have varying degrees of negatively-affecting comorbidities like hyperlipidemia. We evaluated the preconditioning effect of ginsenoside-Mc1 on reperfusion injury-induced myocardial arrhythmias, along with cardiac oxidative stress, endoplasmic reticulum stress protein expression, and histological damage in hyperlipidemic rats, and further, explore the role of JAK2/STAT3 activity.

Methods

Thirty-five Sprague–Dawley rats fed a high-fat diet for eight weeks. Ginsenoside-Mc1 (10 mg/dL, IP) was administered to hyperlipidemic rats daily for one month before IR injury. IR injury was induced by 35 min LAD coronary artery ligation and subsequent 60-min reperfusion. A selective JAK2 inhibitor (AG490) was injected before IR injury. Electrocardiography was recorded and myocardial arrhythmias (ventricular premature complexes, tachycardia, and fibrillation) were evaluated in the reperfusion phase according to Lambeth convention. Hematoxylin-Eosin staining, spectrophotometry, and Western blotting techniques were employed to measure the endpoints.

Results

IR injury in hyperlipidemic rats significantly increased the reperfusion-induced myocardial arrhythmias counts, timing, incidence, and severity. The expression of proteins of endoplasmic reticulum stress (p-PERK, p-eIF2α, CHOP), and oxidative stress marker malondialdehyde were significantly upregulated following IR induction, whereas antioxidant superoxide-dismutase and JAK2/STAT3 proteins expression significantly reduced, as compared with untreated-hyperlipidemic rats. Administration of ginsenoside-Mc1 to hyperlipidemic rats significantly corrected the arrhythmogenic feature of IR injury, reduced phosphorylation and expression of PERK, eIF2α, CHOP, and improved oxidative stress and histological changes. Interestingly, inhibition of the JAK2/STAT3 pathway via AG490 significantly abolished ginsenoside-Mc1-induced cardioprotection.

Conclusions

Taken together, ginsenoside-Mc1 exerts substantial anti-arrhythmogenic influences against myocardial IR injury in hyperlipidemic rats through activation of JAK2/STAT3 pathway and subsequent reduction of oxidative/endoplasmic reticulum stress.
Design of Internet of Things Information Interactive Perception System Based on 5G Mobile Communication Technology in a Hospital Network
Authors: Yang Xiuying , Chen Xiaohong
Published: February 2022

In the communication process of 5G big data Internet of Things, because of the difference of communication data, the data interaction process needs information mutual recognition scheduling, which greatly reduces the effectiveness of the interactive perception system. In order to improve the real-time performance of platform interaction in the Internet of Things environment, an Internet of Things information interaction perception system based on 5G mobile communication technology is designed. This is mainly important in a hospital network. The system perception layer completes the accurate acquisition of Internet of Things information through data acquisition module and transmits it to the application layer through 5G mobile communication module in the network layer. The intelligent interaction module based on context awareness in the application layer will be heterogeneous and unstructured. The Internet of Things perceived data is encapsulated in context as a unified data processing object of the Internet of Things. The context rule-matching algorithm based on Storm is used to achieve accurate matching between heterogeneous and unstructured perceptual data and rules, and an interactive perceptual parallel query scheduling strategy is used to achieve the optimal scheduling of information mutual perception in the Internet of Things. The results show that there is a positive correlation between the validity of sensing temperature information and the amount of sensing data. The average data processing delay of the system is stable at 50 ms, which meets the real-time requirement of data processing.
Surfacing Human Service Organizations’ Data Use Practices: Toward a Critical Performance Measurement Framework
Authors: Fink Alexander , VeLure Roholt Ross
Published: February 2022

Community-level data systems, often called collective impact, increasingly define the landscape of human service data creation. Collective impact strategies develop shared performance measurement metrics across numerous human service organizations (HSOs) in a geographic region to move the needle on specific social problems. Such systems encourage funders to support the development of client tracking and data sharing infrastructure, meaning more HSOs have more information about any given client. However, while many HSOs are using more data than ever, questions remain: how is this data being read, understood, and utilized in HSOs? What differences can we discern in organizational operation and service provision?
This study builds on three years of participant observation as program evaluators in youth-serving organizations (a subtype of HSOs) around the world. It also included a national study of youth-serving organizations with a strong focus on data use. Finally, it includes interviews with program staff in youth-serving organizations and focus group data with young people. Situating this data between the literature on performance measurement in HSOs and critical data studies, we surface emerging tensions in the ways youth-serving organizations are creating and using data, drawing to the fore salient questions for those invested in supporting the just use of data and technology for our communities.
Fostering entrepreneurial thinking in biomaterials education
Authors: Lavoine Nathalie
Published: February 2022

The concept of entrepreneurial thinking is gaining attention in higher education. Originally attributed to entrepreneurs, this concept embraces a set of attitudes, skills, and behaviors that can also help students, engineers, and researchers to succeed academically, professionally, and personally. This editorial discusses the benefits of developing and adopting an entrepreneurial thinking in biomaterials science and engineering. Our society is constantly evolving, and the next generations of engineers and researchers will have to adapt fast to the needs and propose innovative solutions to the demands. A strong entrepreneurial mindset may thus be key for boosting our efforts towards innovation and sustainability.
Nanofibrillated cellulose/nano SiO2/poly(vinyl alcohol) composite films: Evaluation of properties
Authors: Bay Mohammad Ali , Eslam Habibollah Khademi , Bazyar Behzad , Najafi Abdollah , Hemmasi Amir Hooman
Published: February 2022

Effects of nanofibrillated cellulose (NFC) and nano-silicon dioxide on dynamic mechanical thermal analysis and physical properties of nanocomposites films made of poly (vinyl alcohol) (PVOH) were investigated. For this purpose, the nanoparticles were mixed with PVOH at 0%, 5%, and 10% weight. Water absorption, dynamic mechanical thermal, transparency, and wettability properties were evaluated according to corresponding standard test methods. The morphology of nanocomposites was explored by using a field emission scanning electron microscope technique. The films became increasingly opaque with increasing nanoparticles contents, although the composites also retained moderate transparency. According to the results of the tests, the dynamic mechanical thermal (DMTA) properties of PVOH composite films were significantly improved with the increase of NFC and silica nanoparticles loading. The samples containing 20 wt% of nano-SiO2 exhibited higher hydrophobicity compared with that of 20 wt% NFC.
Material selection of natural fibre using a grey relational analysis (GRA) approach
Authors: Maidin Nurul Ain , Sapuan S. M. , Taha Mastura Mohammad , Yusoff Mohd Zuhri Mohamed
Published: February 2022

Numerous situations in daily life necessitate a decision. Several of them entail selecting the best option from a number of available options. In many such cases, no single solution is optimal for all of the performance characteristics. This study proposes using grey relational analysis (GRA), a multiple criteria decision making (MCDM) method, to solve this problem. Material selection is vital in designing and developing products, especially for composites materials requiring special attention. The substitution of conventional materials with natural fibres as base material is commonly practised due to high material consumption in mass-producing plastic components that could harm the environment. Therefore, in this work, natural fibres were chosen as composite reinforcement in the design of cyclist helmets. This approach was used to evaluate the right natural fibre and is able to fulfill the needs of consumers and the environment. From the results, the GRA method was utilised and revealed that pineapple was the best top ranking natural fibre with a grade of 0.5687, followed closely by bamboo with a grade of 0.5678, and abaca with a grade of 0.4966. Error analysis was performed to increase the confidence level of the results obtained.
Experimental investigation of epoxy matrix and pine sawdust reinforced wood-polymer composite materials
Authors: Koyuncu Menderes
Published: February 2022

Mechanical, thermal, and water absorption properties of the composites have been studied as a function of sawdust content, using different weight percentage. The characteristics properties of the composites were studied using differential scanning calorimetry and Fourier-transform infrared spectroscopy. Field emission scanning electron microscopy was used to understand the interfacial bonding. The obtained results showed that the 15 wt% composites exhibited the highest tensile strength (7.5 MPa) and flexural strength (8.9 MPa) compared with the 5 wt%, 30 wt%, 40 wt%, and 50 wt% composites. A good interfacial combination was formed between 15 wt% of sawdust and epoxy resin. In terms of the tensile and flexural strength, the differential scanning calorimetry analysis confirmed that matrix modification could improve the mechanical properties and thermal stability of the composites compared to neat resin. The Fourier-transform infrared spectroscopy spectrum showed the presence of functional groups pertaining to composites. The absorption data of the composite showed that the water uptake increased as the amount of sawdust in the composite increased. The 5 wt%, 15 wt%, 30 wt%, and 40 wt% sawdust composites also displayed less water absorption behavior (1.534%, 1.871%, 2.492%, and 4.127%, respectively) compared to the 50 wt% composite.
Efficient treatment of lead-containing wastewater using bagasse biochar modified via hydroxylapatite
Authors: Zhang Qing , Lu Lin , Liang Meina , Wang Dunqiu , Huang Daolin , Zhu Yinian
Published: February 2022

A hydroxylapatite bagasse biochar composite was prepared via the hydrothermal chemical precipitation method with bagasse as the primary raw material. The adsorption capacity of hydroxylapatite bagasse biochar composite for Pb(II) was determined using a series of batch adsorption experiments. The results showed that the point of zero charge value was near neutral pH, and the optimal pH ranged from 4.0 to 7.0. Langmuir isotherms were suitable for fitting the isothermal adsorption process of Pb(II) by the hydroxylapatite bagasse biochar composite. The maximum adsorption capacity of hydroxylapatite bagasse biochar composite in terms of Pb(II) was 210 mg·g-1 at 25 °C. Fourier transform infrared spectrometry analysis indicated that oxygen-containing functional groups were abundant on the external and internal surfaces of the composite sample, which provided numerous chemical sorption sites and resulted in an increase in the adsorption capacity of the composite sample. The Pb(II) removal mechanism of the hydroxylapatite bagasse biochar composite primarily utilized surface diffusion, electrostatic attraction, surface complexation, ion exchange, and a dissolving-coprecipitation reaction. The composite sample was suitable for the treatment of lead-contaminated water (containing zinc, arsenic, cadmium, etc.), which was a promising environmentally friendly material.
Delignification of hemp stalk using a low transition temperature mixture composed of choline chloride and lactic acid
Authors: Jančíková Veronika , Jablonský Michal
Published: February 2022

This work used a literature search to select the most suitable system for the delignification process of annual plants. This process was evaluated in terms of lignin removal from plant biomass. Based on previous experiments, a low transition temperature mixture (LTTM) was used, which was a mixture of choline chloride and lactic acid in a molar ratio of 1:2. Samples of hemp fibers were examined. The delignification of biomass was monitored by changing the content of the main components. After application of the solvent at a temperature of 100, 120, or 140 °C and a delignification time of 2 or 4 h, the lignin content expressed by Kappa number decreased to the level of 22 to 13.7. Yields of hemp fibers sown after LTTM application ranged from 72.5 to 90.6%. The results confirmed that the use of LTTM (choline chloride/lactic acid) is a suitable system for the extraction of lignin from biomass. The findings showed that LTTM was an effective delignifying agent for hemp, as a relatively low Kappa number of 13.7 and a yield of 75.9% were achieved after only 2 h and at 140 °C.
Agave durangensis vinasse as a biocide for forest pest control
Authors: Bailón-Salas Ana M. , Ordaz-Diaz Luis A. , Domínguez-Calleros Pedro A.
Published: February 2022

In forestry practice, the prevention and fight against insect pests and diseases is a priority to preserve the health of these ecosystems. To combat it, insecticides of chemical and biological origin have been used. However, there are alternatives that have not yet been investigated, e.g., the use of agro-industrial waste. In the mezcal distillation process, polluting liquid residues called vinasses are generated, and these can be considered for pest control. In this project, the effect of vinasse from Agave durangensis subjected to different treatments was studied to evaluate its effect on forest phytopathogenic fungi. The mezcal vinasse was characterized physicochemically and by its metabolites. Furthermore, the percentage of inhibition in vitro of phytopathogenic (causing root wilt) fungi isolated from Pinus cooperi seedlings was studied. The fungi inhibition was related to the vinasse concentration. The lower pH and sterile raw vinasse showed a better inhibition effect. Four phytopathogenic strains of Pinus cooperi were isolated and identified, which corresponded to the genera Fusarium, Aspergillus, and Penicillium. None of the isolated were able to grow in potato dextrose-mezcal vinasse medium (PDMVM). Therefore, the mezcal vinasse showed fungicide activity in vitro against all strains.
Effect of butyric anhydride modification on properties of wood-polylactic acid 3D-printed composites
Authors: Narlıoğlu Nasır
Published: February 2022

Scotch pine wood flour was modified with butyric anhydride to determine the effect of wood modification on the properties of 3D-printed composites. The 3D printer filaments were obtained by mixing wood flour and polylactic acid (PLA) with a twin-screw extruder. The composites were printed via a 3D printer from the obtained filaments. The mechanical, thermal, and morphological properties of the composites were investigated. According to the mechanical test results, the tensile strength values of the modified wood flour (MWF)-added composites were higher than the unmodified wood flour (UMWF)-added composites. It was also observed that the flexural strength and flexural modulus of MWF-added composites decreased compared to the UMWF-added composites. According to the investigation of the thermal properties of the composites, the thermal degradation temperature value of the 20% MWF-added PLA composite was higher than other composites. Therefore, through the investigation of breaking surfaces of the composites using scanning electron microscopy, it was observed that the interface bonding between PLA polymer matrix and wood flour was improved by modification.
Carboxylated nanocrystalline cellulose from Salix psammophila prepared by sulfuric acid hydrolysis combined with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidation
Authors: Zhong Yuan , Gao Xueyi , Zhang Wanqi , Wang Xue , Wang Kebing
Published: February 2022

Salix psammophila (SP) is an important sand plant, and could be utilized to develop high-value products. In this work, SP was used as raw material and cellulose nanocrystals (CNC) were prepared by hydrolysis in 64 wt% sulfuric acid (H2SO4) solution, and then, TEMPO/NaBr/NaClO system was used to oxidize CNC to obtain TEMPO-oxidation-cellulose nanocrystals (TOCNC). Fourier transform infrared analysis (FTIR) revealed that after oxidation, there were obvious carboxyl functional groups. Scanning electron microscopy (SEM) showed that both CNC and TOCNC were agglomerated. Under atomic force microscope (AFM) and transmission electron microscopy (TEM), CNC and TOCNC presented short rod fibers, average diameters of 23 nm and 21 nm and average lengths of 213 nm and 165 nm, respectively. X-ray photoelectron spectroscopy analysis (XPS) showed that TOCNC generated a new energy spectrum peak at 289.06 eV, which was the peak of C=O in the carboxyl group. The crystallinity of the CNC and TOCNC were 70.8% and 26.9%, respectively.
Assessment of the differences between juvenile and mature woods of Populus alba trees in the longitudinal and radial axes of the stem
Authors: Tichi Ali Hassanpoor
Published: February 2022

The aim of this study was to evaluate the differences between juvenile and mature woods of Populus alba trees in the axial and radial directions of the stem. For this purpose, three stands of P. alba trees were randomly chosen and cut from at their diameter at breast height. Three disks with a thickness of 5 cm were taken at three different height levels along the tree stems. The specimens were sequentially cut in the radial position according to the ISO standards method. The results indicated that there are significant differences in the physical and biometric features of P. alba trees in the longitudinal and radial axes of the stem. As the height from the base of the tree to the top of the stem increased, the oven-dry density, basic density, and fiber biometric factors decreased. Moreover, as the distance from the pith to the bark increased, the oven-dry density, basic density, and fiber biometric factors increased. The microscopic study represented that the P. alba is a semi-ring-porous hardwood with distinct growth ring boundaries, simple perforation, homogenous rays, and alternative inter-vessel pits.
Effects of cutting parameters on the sound level and surface quality of sawn wood
Authors: Gholamiyan Hadi , Gholampoor Behnam , Tichi Ali Hassanpoor
Published: February 2022

This study investigated the effect of cutting conditions effects on sound level and surface quality in softwood and hardwood. The sound emission level caused by cutting process (band saw) as well as the surface roughness and topography of the wood samples were evaluated. A direct relationship was found between sound emission level and density, moisture content, feeding rate, and dimensions of the samples. Straight cutting of the samples caused less sound emission than cutting in a curved direction. The protective effect of the earmuffs was very significant, reducing the sound emission level from 88 dB to 38 dB. The results showed that with increasing the density and dimensions of the samples, the surface roughness decreased, while with increasing the moisture content and feeding rate, changing the cutting direction from straight to curved, the surface roughness of the samples increased.
Evaluation of the strength characteristics of Cunninghamia lanceolata timber using continuous mechanical stress rating equipment
Authors: Lee Chiaju , Lin Chihhsein , Chung Minjay , Tsai Mingjer
Published: February 2022

Before timber is used for engineering and structural purposes, it is necessary to grade the strength of the timber. In order to obtain the static modulus of elasticity value of timber quickly and accurately, this study used ultrasonic waves and continuous mechanical stress rating equipment and two non-destructive test methods to analyze the correlation between the non-destructive test measured value and the static modulus of elasticity value. It also evaluated the influence of the feeding orientation of the boards, the forward and reverse feed directions, feeding speed, and break area ratio. The analysis results indicated that the modulus of elasticity value determined through continuous mechanical stress rating equipment had the highest correlation with the static modulus of elasticity value. Moreover, according to the results, the feeding orientation of the boards, the forward and reverse feed directions, and the feeding speed did not influence the prediction of the continuous mechanical stress rating equipment modulus of elasticity value. Meanwhile, to ensure the accuracy and uniformity of the continuous mechanical stress rating equipment modulus of elasticity detection value, it is necessary to avoid an excessively high break area ratio in Cunninghamia lanceolata timber during the preparation process.
A folding method to increase the rigidity of paperboard tray packages
Authors: Niini Arvo , Tanninen Panu , Laukala Teija , Varis Juha , Leminen Ville
Published: February 2022

The flange of press-formed paperboard trays was reshaped in this work with a developed folding method to increase the rigidity of the trays. The tray rigidity was evaluated with compression, torsion, and storing tests. The rigidity of the folded trays and the reference trays was compared, and the quality of the trays was investigated with an optical analysis. The folding temperature was altered to 23, 60, and 90 °C to compare the effects of heat input on the tray rigidity. The compression and torsion test results linked the increased tray rigidity to the additional heat input and surface pressure induced to the material in the folding phase. The trays that were folded at 90 °C showed a 43% higher compression force and a 12% smaller torsion angle compared to the reference trays. The storing tests showed an unclear effect on the tray rigidity to the dimensional stability, and the optical analysis depicted similar quality between the folded and the reference trays. The folding method was found to enhance the stacking and end use capabilities of paperboard tray packages, and the use of higher folding temperatures was suggested to increase the strength and stiffness of the trays.
Anatomical characteristics for identification and quality indices of four promising commercial bamboo species in Java, Indonesia
Authors: Maulana Muhammad Iqbal , Jeon Woo Seok , Purusatama Byantara Darsan , Kim Jong Ho , Prasetia Denni , Yang Go Un , Savero Alvin Muhammad , Nawawi Deded Sarip , Nikmatin Siti , Sari Rita Kartika , Febrianto Fauzi , Lee Seung Hwan , Kim Nam Hun
Published: February 2022

The anatomical characteristics in the culms of the four promising Indonesian bamboo species, including Dendrocalamus asper, Dendrocalamus giganteus, Bambusa vulgaris var. vulgaris, and Bambusa vulgaris var. striata, were investigated to produce an identification key and quality indices for further effective utilization. The crystalline properties of the bamboo culm were determined using X-ray diffraction analysis. Dendrocalamus asper and Bambusa vulgaris var. striata showed vascular bundle type IV, while Dendrocalamus giganteus and Bambusa vulgaris var. vulgaris displayed vascular bundle type III. The vascular bundle density in the bamboo culms increased from the bottom to the top part and was higher in the outer part than in the inner part. The fiber portion and length in the outer part were higher than those in the inner part, opposite of those in the parenchyma portion. Dendrocalamus giganteus had the largest vessel and parenchyma diameter, while Bambusa vulgaris var. vulgaris had the smallest. Bambusa vulgaris var. vulgaris had the longest parenchyma, while Bambusa vulgaris var. striata and Dendrocalamus giganteus had the shortest. The outer part of the four bamboo culms showed higher relative crystallinity than the inner part. All anatomical parameters, except for crystallite width, showed a variation in the radial direction of the four bamboo culms but did not show a consistent tendency vertically. This study revealed that the anatomical properties were different between bamboo species and could be used for species identification and quality evaluation indices of the culms.
Comparison of carbohydrate composition in lignocellulosic biomass by high performance liquid chromatography and gas chromatography analysis
Authors: Jung Ji Young , Ha Si Young , Yang Jae-Kyung
Published: February 2022

The carbohydrate composition (glucose, xylose, mannose, galactose, and arabinose) of lignocellulosic biomass Liriodendron tulipifera, Populus nigra × Populus maximowiczii, Populus alba × Populus glandulosa, Populus euramericana, Salix alba, Quercus variabilis, Robinia pseudoacacia, Zelkova serrata, Abies holophylla, Pinus rigida, rice straw, and peanut hull was investigated based on high-performance liquid chromatography (HPLC) and gas chromatography (GC) analyses derived from ASTM and NREL methods. The glucose content was higher in HPLC than in GC analysis, and the xylose, mannose, galactose, and arabinose contents were higher in GC than in HPLC analysis. The difference in carbohydrate composition was noticeable in the glucose, mannose, and arabinose contents of Abies holophylla and Pinus rigida, and this was affected by the species. A decision tree, as a data mining and artificial intelligence method, is a reliable and simple variable selection tool. This technique was used for carbohydrate analysis classification. Accordingly, 432 monosaccharide content reading data and analysis methods were used for model checking. It was found that arabinose was the most important splitting variable in carbohydrate analysis, and other monosaccharides did not influence the assay decision. However, the selection of a determination method for each sample should be considered comprehensively in future studies.
Calibration of parameters for discrete element simulation model for alfalfa with different moisture contents based on angle of repose test
Authors: Wang Haoyi , Wu Pei , He Hongkai , Ma Yanhua , Bu Ku , Xue Jing
Published: February 2022

During the simulation analysis of the discrete element method (DEM) for the alfalfa compression process, the input parameters in DEM software had a significant effect on simulation results. To obtain simulation parameters of the alfalfa with different moisture contents, a combination of angle of repose tests and simulation optimization design are presented in this paper. The repose angle of the alfalfa with moisture contents of 2.7%, 13.4%, 19.9%, 33.1%, and 74.5% was measured, and the results were 41.99˚, 38.30˚, 47.47˚, 56.31˚, and 63.09˚, respectively. Inclinometer tests, shear test, and restitution test were performed to evaluate the contact parameters. Taking contact parameters as the calibration object, the Plackett-Burman test was used to screen out which parameters had significant influence on the repose angle. The results of variance analysis showed the surface energy was the most significant parameter in the alfalfa repose angle test for each moisture content. Based on the Box-Behnken test, a second-order regression model of repose angle was obtained and the significance parameters were optimized and calibrated. The parameters calibrated in this paper can provide a reference for other simulations of alfalfa utilization.