bluuebunny/crossref_metadata_2025 huggingface dataset:
Social distancing laws cause only small losses of economic activity during the COVID-19 pandemic in Scandinavia
Authors: Sheridan Adam , Andersen Asger Lau , Hansen Emil Toft , Johannesen Niels
Published: August 2020

Significance

Social distancing laws that restrict the activities of private businesses are often seen as sacrificing the economy to save lives from COVID-19. Indeed, many countries have experienced massive reductions in consumer spending around the time they began to shut down. We show that these restrictions are, in fact, responsible for only a small portion of the drop in consumer spending. This suggests that the virus itself is responsible for the majority of the economic damage. We find that social distancing laws may provide an economic benefit: the laws reduce the economic activity of the low-risk population and can thus protect those with the greatest risk of mortality from also bearing the greatest burden in terms of reduced spending.
Computer-mediated discourse in context
Authors: Fetzer Anita
Published: August 2020

This paper examines the particularisation of the pragmatic
universals of contextualisation, indexicality of communicative action and
implicature in computer-mediated discourse. It adopts a discourse-pragmatic
perspective to account for the interdependencies between the contextual constraints
and requirements of the medium on the one hand, and the multilayeredness and
hypertextuality of computer-mediated discourse on the other. Particular attention is
given to the importation of context and provision of background information, and to
their contribution to the co-construction of discourse common ground. Utilising
data, metadata and metarepresentations from the coverage of a former refugee taking
up a Lord Mayor post, the paper shows how the pragmatic universals undergo
medium-specific particularisation and count as multiply contextual communicative
actions with multilayered production and reception formats.
Speech acts and the dissemination of knowledge in social networks
Authors: Labinaz Paolo , Sbisà Marina
Published: August 2020

This paper analyzes how social network users engaged in
discussions under a public post contribute to knowledge dissemination through their
verbal behavior in the light of an Austin-based speech-act theoretical framework. We
first argue that such a framework can be applied not only to face-to-face
interaction, but also to internet-mediated communication, since it identifies kinds
of illocutionary acts on the basis of recognizable procedure patterns which can be
made manifest through different communication channels. We then examine to what
extent the performance of different kinds of illocutionary acts contributes to
knowledge dissemination through the achievement of their characteristic effects or
other aspects of their procedure patterns. For each of four main classes of
illocutionary acts, we discuss examples from comments on Facebook posts concerning
health- and politics-related issues.
Humour and self-presentation on WhatsApp profile
status
Authors: Maíz-Arévalo Carmen
Published: August 2020

Self-presentation encompasses a set of strategies through which
individuals communicate an image of themselves to others. Self-presentation has been
widely studied both in face-to-face communication and online. Most online research,
however, has focused on social networking sites, blogs, chatrooms, etc. while less
attention has been paid to other online means of communication such as
WhatsApp. The aim of this chapter is to analyse self-presentation
on WhatsApp statuses. More specifically, I focus on the use of
humour as a self-presentation strategy in WhatsApp statuses and
ascertain whether or not there are common patterns with regard to gender or age. To
this purpose, a corpus of 206 WhatsApp statuses in Spanish was
analysed following both a quantitative and qualitative methodology. Results shows
the existence of recurrent patterns connected to these variables, which seem to play
a crucial role to determine the choice of humour as a self-presentation
strategy.
Candidates’ use of Twitter during the 2016 Austrian presidential
campaign
Authors: Gruber Helmut
Published: August 2020

This paper explores the Twitter use by the candidates of the
2016 Austrian presidential campaign which lasted for almost one year and required
three ballots in sequence. The data corpus consists of all Twitter messages the
candidates posted during the campaign. Drawing on theoretical considerations
regarding politicians’ and political parties’ use of internet communication
technologies (esp. the innovation vs. the normalization hypotheses), the paper
explores the content level, the use of rhetorical actions, and selected aspects of
the interpersonal level of the data. Results show that the candidates’ communication
strategies cannot fully be explained by either of the two hypotheses and hence that
none of them can predict electoral success in this specific political campaign. It
is concluded that the two proposed hypotheses concerning the use of internet
communication technologies in the field of politics are too broad and that they have
to be modified to account for contextual aspects of specific political communication
situations.
Migration through the English-Greek translated press
Authors: Sidiropoulou Maria
Published: August 2020

The chapter problematizes pragmatic shifts in 2015
web-retrieved English-Greek translated press news texts on the 2015 refugee crisis
in Europe. There seems to be a gate-keeping role of the traditional media to locally
reshape global dissemination of inference-making through verbal material, which
changes the realism of the news. The study analyses patterns of shifts in verbally
mediated instances of suffering and migration in the Greek translated press to show
the contribution of the receiving institutions’ and the translator’s critical view
in re-narrating news items in specific historical and political conditions. Managing
discoursal inferences may involve making intended inferences explicit in a target
version, reshaping world representations to affect inclusion/exclusion strategizing
in the reception environment, manipulating metaphors to avoid unintended
connotations which may be favoured on a global scale, etc. Local perceptions of
global conflicts may de/mobilize public sentiment and construct ethical intended
sensibilities and citizenship roles.
AKT-dependent NOTCH3 activation drives tumor progression in a model of mesenchymal colorectal cancer
Authors: Varga Julia , Nicolas Adele , Petrocelli Valentina , Pesic Marina , Mahmoud Abdelrahman , Michels Birgitta E. , Etlioglu Emre , Yepes Diego , Häupl Björn , Ziegler Paul K. , Bankov Katrin , Wild Peter J. , Wanninger Stefan , Medyouf Hind , Farin Henner F. , Tejpar Sabine , Oellerich Thomas , Ruland Jürgen , Siebel Christian W. , Greten Florian R.
Published: August 2020

Recently, a transcriptome-based consensus molecular subtype (CMS) classification of colorectal cancer (CRC) has been established, which may ultimately help to individualize CRC therapy. However, the lack of animal models that faithfully recapitulate the different molecular subtypes impedes adequate preclinical testing of stratified therapeutic concepts. Here, we demonstrate that constitutive AKT activation in intestinal epithelial cells markedly enhances tumor invasion and metastasis in Trp53ΔIEC mice (Trp53ΔIECAktE17K) upon challenge with the carcinogen azoxymethane. Gene-expression profiling indicates that Trp53ΔIECAktE17K tumors resemble the human mesenchymal colorectal cancer subtype (CMS4), which is characterized by the poorest survival rate among the four CMSs. Trp53ΔIECAktE17K tumor cells are characterized by Notch3 up-regulation, and treatment of Trp53ΔIECAktE17K mice with a NOTCH3-inhibiting antibody reduces invasion and metastasis. In CRC patients, NOTCH3 expression correlates positively with tumor grading and the presence of lymph node as well as distant metastases and is specifically up-regulated in CMS4 tumors. Therefore, we suggest NOTCH3 as a putative target for advanced CMS4 CRC patients.
Pilot comparison CCQM-P177—monoterpenes in nitrogen at 2.5 nmol mol−1 final report
Authors: Liaskos Christina , Rhoderick George , Hodges Joseph , Possolo Antonio , Wilke Olaf
Published: August 2020

Growing awareness of the impact of monoterpenes on climate, atmospheric chemistry, and indoor air quality has necessitated the development of measurement standards to globally monitor and control their emissions. For National Metrology Institutes to develop such standards, it is essential that they demonstrate measurement equivalence for assigned values at the highest levels of accuracy. This report describes the results of a pilot comparison for 4 key monoterpene species: α-pinene, 3-carene, R-limonene and 1,8-cineole, at a nominal amount-of-substance fraction of 2.5 nmol mol−1. The objective of this comparison is to evaluate participant capabilities to measure trace-level monoterpenes using their own calibration techniques.

Main text

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Lowest observed surface and weld losses in fused silica fibres for gravitational wave detectors
Authors: Cumming A V , Sorazu B , Daw E , Hammond G D , Hough J , Jones R , Martin I W , Rowan S , Strain K A , Williams D
Published: August 2020

High purity fused silica has become the cornerstone choice for use in the final monolithic stage of the mirror suspensions in the gravitational wave observatories Advanced LIGO (aLIGO) and Advanced Virgo (AdV). The ultra-low thermal noise contributed by these suspensions is one of the key improvements that permitted the Nobel prize winning first direct measurement of gravitational waves in 2015. This paper outlines the first in situ study undertaken to analyse the thermal noise of the final monolithic stage of the aLIGO Hanford detector mirror suspensions. We analysed short operational periods of this detector, when high excitation of the transverse ‘violin’ modes of the silica suspension fibres occurred. This allowed detailed measurements of the Q-factor of violin modes up to order 8 of individual fibres on separate masses. We demonstrate the highest silica fibre violin mode Q-factors yet measured of up to 2 × 109. From finite element modelling, the dominant surface and weld losses have been calculated to be a factor of 3 to 4 better than previously accepted, and as a result, we demonstrate that the level of noise in the aLIGO final stage silica suspensions is around 30%–40% better than previously estimated between frequencies of 10–500 Hz. This leads to an increase in the estimated event rate by a factor of 2 for aLIGO, if suspension thermal noise became the main limitation to the sensitivity of the detector.
Generalized uncertainty principle in resonant detectors of gravitational waves
Authors: Bhattacharyya Sukanta , Gangopadhyay Sunandan , Saha Anirban
Published: August 2020

With the direct detection of gravitational waves (GWs) by advanced LIGO detector, a new ‘window’ to quantum gravity phenomenology has been opened. At present, these detectors achieve the sensitivity to detect the length variation (δL),

O
≈
1

0

−
17

−
1

0

−
21

metre. Recently a more stringent upperbound on the dimensionless parameter β
0, bearing the effect of generalized uncertainty principle (GUP) has been given which corresponds to the intermediate length scale

l

i
m

=

β

0

l

p
l

∼
1

0

−
23

m

. Hence the flavour of the GUP can be realised by observing the response of the vibrations of phonon modes in such resonant detectors in the near future. In this paper, therefore, we calculate the resonant frequencies and transition rates induced by the incoming GWs on these detectors in the GUP framework. It is observed that the effects of the GUP bears its signature in both the time independent and dependent part of the gravitational wave-harmonic oscillator Hamiltonian. We also make an upper bound estimate of the GUP parameter.
Horseshoes and invariant tori in cosmological models with a coupled field and non-zero curvature
*
Authors: Butler Leo T
Published: August 2020

This paper studies the dynamics of a family of Hamiltonian systems that originate from Friedman–Lemaître–Robertson–Walker space-times with a coupled field and non-zero curvature. In four distinct cases, previously considered by Maciejewski, Przybylska, Stachowiak and Szydowski, it is shown that there are homoclinic connections to invariant submanifolds and the connections split. These results imply the non-existence of a real-analytic integral independent of the Hamiltonian.
An ultrathin acoustic carpet cloak based on resonators with extended necks
Authors: Guo Jingwen , Zhou Jie
Published: August 2020

By employing a set of resonators with extended necks, an ultrathin acoustic carpet cloak with a thickness of about 1/30th of the operation wavelength is proposed to achieve effective cloaking around a bump at 1000 Hz. The cloak is composed of a periodic array of supercells. The supercell is constructed by a solid unit and seven inhomogeneous resonators with different extended necks. The elements in the supercell are capable of achieving distinct phase shifts ranging from 0 to 2π in a phase increment of π/4. To demonstrate the effectiveness of the cloak, both normal incidence and oblique incidence (incident angle equals to 30°) plane waves impinging on a cloaked triangular bump are investigated numerically and validated experimentally. The results show that it is possible to conceal the bump by wrapping over the surface of the bump through using the proposed ultrathin carpet cloak. As a resonant-element based acoustic device, the cloak exhibits invisibility in the frequency range from 980 to 1070 Hz. The proposed acoustic metasurface offers a simple and compact solution for acoustic cloaking and may hold promise in realistic applications.
Assisted cold start method for GPS receiver with artificial neural network-based satellite orbit prediction
Authors: Yang Ruihong , Song Zhongguo , Chen Lingfeng , Gu Yue , Xi Xiaoli
Published: August 2020

Traditional GPS receivers usually take a long time to obtain their first position solution in the cold start mode. This paper presents a method for assisting the cold start of GPS receivers by autonomous satellite orbit prediction. In this method, the time-consuming broadcast ephemeris collection process in a traditional cold start is replaced by orbit prediction to obtain the satellite position information required for positioning. Thus, the time to first fix of the receiver can be reduced significantly. In addition, since the traditional orbit prediction algorithms based solely on physics-based models have limited accuracy, a hybrid model composed of dynamic models and artificial neural network models for orbit prediction is proposed to improve the accuracy of the orbit prediction. Taking GPS PRN1 as an example, the simulation results show that, in 75% of cases, the satellite position error after 7 days’ prediction with the dynamic models is less than 162.84 m, but this value can be reduced to 46.06 m with the proposed hybrid model; the improvement rate achieved is approximately 71.71%. Some positioning experiments with simulated satellite signals were conducted to assess the first-fix accuracy of a GPS receiver with the proposed satellite orbit prediction function. The results of this study offer insights for the design of advanced assisted GPS receivers.
Effect of surfactants on the lightning breakdown voltage of palm oil and coconut oil based Al2O3nanofluids
Authors: Mohamad Nur Aqilah , Azis Norhafiz , Jasni Jasronita , Ab. Kadir Mohd Zainal Abidin , Yunus Robiah , Yaakub Zaini
Published: August 2020

In this paper, the effect of different types of surfactants on the lightning breakdown voltages of palm oil (PO) and coconut oil (CO) based aluminium oxide (Al2O3) nanofluids is investigated. Three different types of surfactants were used in this study known as cationic (cetyl trimethyl ammonium bromide (CTAB)), anionic (sodium dodecyl sulfate (SDS)) and non-ionic (oleic acid (OA)). The volume percentage concentrations of Al2O3dispersed into PO and CO were varied from 0.001% to 0.05%. The ratio of surfactant to the nanoparticles was set to 50% from the volume concentration of nanoparticles which equivalent to 1:2. In total, two types of refined, bleached and deodorized palm oil (RBDPO) and one type of CO were examined for lightning breakdown voltage. The test was carried out based on needle-sphere electrodes configuration with 25 mm gap distance. The presence of Al2O3improves both positive and negative lightning breakdown voltages of RBDPO and CO. Under the positive and negative polarities, the CTAB does provide further improvements on the lightning breakdown voltages of RBDPOA (1st type of samples) and CO at most of the volume of concentration of Al2O3. SDS and OA could also further improve the lightning breakdown voltage of CO at certain volume concentration of Al2O3. On the other hand, the lightning breakdown voltage of RBDPOB based Al2O3nanofluid (2nd type of samples) does not further improve with the introduction of surfactants. At most of the volume concentration of Al2O3, the introduction of CTAB further increases the times to breakdown and decrease the average streamer velocities of RBDPOA under both polarities. The same finding is observed for CO under positive polarity with CTAB and SDS as well as under negative polarity in the presence of all surfactants. The streamer velocities and times to breakdown patterns of RBDPOB based Al2O3nanofluid are inconsistent in the presence of all surfactants. It is found that RBDPO and CO based Al2O3nanofluids have second mode of streamer whereby the streamer velocities are from 1 km s−1to 1.63 km s−1regardless with or without surfactants.
Recent progress of superconducting fault current limiter in China
Authors: Zhang GuoMin , Wang Haonan , Qiu Qinggquan , Zhang Zhifeng , Xiao Liye , Lin Liangzhen
Published: August 2020

With the increase of electricity demand and the rapid development of renewable energy generation, it is becoming more and more important to ensure the safety and stability of power grid, where a superconducting fault current limiter (SFCL) could play an important role. In recent years, a lot of research work has been done in China on the application of high temperature superconducting (HTS) power technology, especially in the aspects of superconducting fault current limiting technology, superconducting fault current limiting-breaking technology, superconducting fault current limiting- magnetic energy storage technology, and superconducting fault current limiting transformer technology. A number of demonstration projects on SFCL were also conducted. In this paper, the research progress of HTS fault current limiters (both AC and DC) in China in recent years is introduced, including the completed projects and the on-going work. The possible application direction of SFCL in the future is proposed.
Coulomb-corrected strong-field approximation based on a genetic algorithm
Authors: Yang Shidong , Song Xiaohong , Liu Xiwang , Zhang Hongdan , Shi Guangluo , Yu Xianhuan , Tang Yajuan , Chen Jing , Yang Weifeng
Published: August 2020

Coulomb-corrected strong-field approximation (CCSFA), which integrates Coulomb potential and the interference effects, is a semiclassical method successful in the study of atomic strong-field ionization. However, it is difficult to numerically solve the saddle-point equation describing tunnelling in the CCSFA, especially for complex laser fields such as elliptically or orthogonally polarized two-color laser fields. In this work, we propose an efficient method based on the genetic algorithm (CCSFA-GA) to overcome this difficulty. The accuracy of our method is verified by comparing our result with the calculation of the standard CCSFA on a hydrogen atom, subjected to an intense laser field. Moreover, we show that the result of the numerical solution of the time-dependent Schrödinger equation with an elliptically polarized laser field can be well reproduced by the CCSFA-GA.
Detection of Coffee Bean Damage in The Roasting Process Based on Shape Features Analysis
Authors: Gunadi I G A , Artha I P M K , Christyaditama I G P , Wicaksana G A S , Martina I M
Published: August 2020

Many studies raise the issue of analysis on the quality of coffee beans (green beans). Green beans are the term used to indicate coffee beans before roasting. The importance of analyzing the quality of coffee beans not only in coffee beans but also in rice seeds. Rice seeds are used as a mixture in the roasting process of coffee. Analysis of the quality of roasted coffee is very important. In roasted coffee beans can be damaged and changes to the coffee beans. Some types of damage to coffee beans include, blackened seeds, partially blackened seeds, browned seeds, broken seeds, perforated seeds, epidermis seeds, horned skin seeds, too young seeds, spotted seeds, and dirty seeds. This study focuses on one of the damage factors, namely broken coffee beans after broken beans. In this study, analysis of roasted coffee quality was determined by shape analysis. The shape analysis uses elongation values. there are two categories of classification, the first class of coffee is of good quality, and the second is coffee with poor grade. Classification is good if the elongation value is more than 0.85, for other conditions it is classified as bad. The results of this study have the following accuracy values, at coffee with a classification of good accuracy of 93.4%, while those at coffee with a bad classification of accuracy are 78.5%.
Parameters Estimation Of Rayleigh Distribution In Survival Analysis On Type Ii Censored Data Using The Bayesian Method
Authors: Elviana Erma , Purwadi Joko
Published: August 2020

This research aims to determine the estimation of Rayleigh’s distribution parameters on the data survival analysis of type II of tuberculosis patients. The method used in this research is the Bayesian method to perform estimate parameters. The process estimation parameter using the Bayesian method requires information from the likelihood function and the prior distribution. The prior distribution used was the prior distribution of Jeffreys. In this study, estimates of Rayleigh’s distribution parameters were applied in the survival analysis data of tuberculosis sufferers. And the value of estimated parameters in patients with tuberculosis acquired θ = 0.001097324 and the changes of the survival value decreased near to zero.
Modified Public Key Cryptosystem Based On Circulant Matrix
Authors: Maxrizal  , Gusti Nyoman Yudi Hartawan I , Jana Padrul , Desy Aniska Prayanti Baiq
Published: August 2020

Experts believe that public key cryptosystems on non-commutative algebraic structures are resistant to the attack of quantum algorithms. In recent years, public key cryptosystems based on Polynomial Symmetrical Decomposition (PSD) on the non-commutative group have been developed. However, they are vulnerable to direct attack, linearization equations attack, and overdefined systems of multivariate polynomial equations attack. This cryptosystem has also been improved by experts. However, the operation of the proposed PSD Improvement still uses complex computing and untested. Therefore in this paper, we replace PSD on a non-commutative group into a non-commutative matrix group. We chose the circulant matrix on the key agreement protocol and the key distribution. The results show that the cryptosystem proposed on the circulant matrix is resistant to direct attack, linearization equations attack, and overdefined systems of multivariate polynomial equations attack.
Development of Mathematics Learning Device Based on Cooperative Model Type of Think Talk Write that Supported by Edmodo for Developing the Mathematics Problem Solving Skills
Authors: Adikana Wiandari Yadnya Ni Wayan , Made Ardana I , Gusti Putu Suharta I
Published: August 2020

This research aims to gather the mathematics learning device based on cooperative model type of think talk write that supported by Edmodo that has a validity, practical, and effective as an effort to improve student problem solving skills on mathematics. This research classified as a type of design research by following the design research procedure by Plomp that includes preliminary phase, prototype phase, and assessment phase. The subject of this research are students of grade X of Senior High School Number 2 Negara, they are 20 students of grade X MIPA 4 for limited tests, 36 students of grade X MIPA 2 for field test I, and 36 students of grade X MIPA 1 for field test II. Learning device that developed are students’ books and teachers’ books that supported by Edmodo. Students book is a mathematics book that intended by the researcher is a mathematics book that discus the trigonometry for grade X. Results of the research shows that learning device that developed fulfilled the validity criteria, practically criteria, and effectivity criteria that expected. Characteristics on the students’ book and teacher’s book are interestingly designed and adapted to the syntax of cooperative model type of think talk write that supported by Edmodo.
The Effect Of Guided Discovery Learning Model Assisted By Open-Ended Student Worksheets Towards Mathematical Problem Solving Ability Reviewed Of Student’s Emotional Intelligence
Authors: Mira Pratiwi Kadek , Gusti Putu Sudiarta I , Suweken Gede
Published: August 2020

This study aimed to find out whether students’ mathematics problem-solving ability taught using guided discovery learning model assisted by open-ended student worksheets is better than those using conventional learning. This research used a sequential mixed method that combined quantitative and qualitative research. Posttest only control design used for the quantitative data, while descriptive analysis used for the qualitative data. The population of the research was 349 students from the whole tenth grade in state high school of SMAN 5 Denpasar-Bali. In addition, cluster random sampling had done after testing the sample’s equivalent. The data obtained were analyzed using the t-test. The results of quantitative data indicate that: (1) students’ mathematics problem-solving ability taught using guided discovery learning model assisted by open-ended student worksheets is better than those using conventional learning, (2) in the group of higher emotional intelligence level and the group of lower emotional intelligence level, students’ mathematics problem-solving ability taught using guided discovery learning model assisted by open-ended student worksheets is better than those using conventional learning. The results of qualitative data indicate that guided discovery learning model assisted by open-ended student worksheets is able to give a positive contribution towards students’ mathematics problem-solving ability.
The Effectiveness Of Problem-Based Interactive Physics E-Module On High School Students’ Critical Thinking
Authors: Sujanem Rai , Nyoman Putu Suwindra I , Suswandi Iwan
Published: August 2020

This study aimed at analyzing the effectiveness of an interactive physics e-module (IPEM) to improve students’ critical thinking skill (CTS). IPEM is a module that contains unstructured problems, physics phenomena in the form of animations, videos, examples, and CTS problems. This IPEM was presented in the blended problem-based learning (BPBL) model. The population consisted of all tenth grade students at SMAN 2 and SMAN 4 Singaraja and classes X1 and X4 in SMAN 2 Singaraja and SMAN 4 Singaraja were selected as the sample by using a random sampling technique. The study used a quasi-experiment one group pre-test and post-test design. Before the lesson was taught by using IPEM, the students were given a CTS pretest. At the end of the lesson, they were given the same test (post-test). The data were analyzed using a paired t-test. The results showed that the average students’ cts before using IPEM was 22.7 , falling into a poor category, and the results showed that the average students’ cts before using IPEM was 59.1, falling into a medium category. The using a paired t-test result shows that there is a significant difference in the students’ CTS before and after using the IPEM. The students’ CTS after using IPEM is better than before using IPEM in learning process. That is why the IPEM in the BPBL model is effective to improve the students’ CTS of high schools.
Preparation of Nanocomposite Silver-Chitosan-Alginate Film as Antibacterial Material
Authors: Susilowati E. , Maryani  , Ashadi  , Masykuri M. , Hastuti B.
Published: August 2020

Preparation of silver-chitosan-alginate (Ag/Kit/Alg) nanocomposite film as an antibacterial material has been done. Nanocomposite film of Ag/Chit/Alg was carried out through casting method of colloidal nanocomposite Ag/Chit/Alg). Colloidal is made through a chemical reduction method of AgNO3 precursor salts assisted by sunlight with chitosan as a stabilizer agent and reducing as well and NaOH as an accelerator. Furthermore, alginate solution is added to form Ag/Kit/Alg nanocomposite colloidal. The formation of silver nanoparticles was indicated by the appearance of localize surface plasmon resonsnce (LSPR) phenomenon which was characterized using a UV-Vis spectrophotometer. The shape and size of silver nanoparticles were characterized using TEM. Characterization of Ag/Kit/Alg nanocompsite films includes swelling, mechanical properties, solubility and water vapor permebility (WVP). Testing of antibacterial activity was carried out on film Ag/Chit/Alg nanocomposit using diffusion method. The results showed that the formation of silver nanoparticles was characterized by the appearance of LSPR phenomenon at the peak of 403.50 - 412.50 nm. Silver nanoparticles are spherical shape with a size dominated at 5-9 nm. The physical and mechanical properties of films are influenced by the concentration of silver nanoparticles. The greater concentration of precursor salt AgNO3 increase swelling and solubility of Ag/Chit/Alg nanocomposte film. The tensile strength of the film tends to decrease due to the presence of Ag nanoparticles. The nanocomposite film of Ag/Chit/Alg has a rough structure with a higher Water Vapor Permeability value compared to Ag/Chit films. The nanocomposit films of Ag/Kit/Alg have high antibacterial activity against Escherechia coli (E. coli) ATCC 25922 and Staphylococcus aureus (S. Aureus) ATCC 25923.
Tio2 Purification From Ilmenite The Tin Industry By-Product For Pigment
Authors: Aviandharie S A , Aidha N N , Jati B N , Ermawati R , Cahyaningtyas A A
Published: August 2020

Ilmenite deposits, a by-product of the tin industry in Bangka, cause environmental problems. Ilmenite is very abundant and has great potential because it still contains 53.83% titanium oxide. One of TiO2 benefits is for pigment. TiO2 pigment in Indonesia still imported. TiO2 pigment can be applied to various industrial sectors such as paints, coatings, fillers, semiconductor materials. This research aims to extract TiO2 from ilmenite with purity level above 80%. The TiO2 extraction used repeated leaching methods with sulfuric acid. Then followed by the hydrolysis process with the addition of seed and calcined. TiO2 products were analyzed using X-ray fluorescence (XRF) and X-ray diffraction (XRD). The content of TiO2 obtained in this process is 83.36% and is in the form of rutile crystals. The purity and crystal formed of this TiO2 product suitable with the minimum standards of TiO2 pigments required by ASTM D 476 (2015). This research can be the alternative to solve environmental problems in the tin industry while increasing the economic value as TiO2 products that has great market potential in Indonesia since there is no TiO2 industry in Indonesia.
Adsorption of Methylene Blue Dyes Using Pectin Membrane
Authors: Hastuti Budi , Nur Afifah Siti , Mulyani Bakti , Susilowati Endang
Published: August 2020

Environmental pollution caused by methylene blue textile dyes is very dangerous for the aquatic environment and human health. To overcome this problem, various adsorbents have been developed for the processing of methylene blue liquid waste. This aim of this research is to know the ability of pectin membrane toward methylene blue dyes. Pectin is a biomaterial isolated from the plant cell walls. Pectin is an anionic polymer, many contain active groups which able to bind positive ions of methylene blue. This method of this research is an experimental method in the laboratory. Pectin adsorbent membrane was made by dissolving of pectin into a 5% acetic acid solution. The optimal condition of the adsorption of methylene blue by pectin membrane was determine. The functional groups of pectin membranes were analyzed by infra red spectroscopy. The adsorption of methylene blue was analysis by using Ultraviolet-Visible Spectroscopy. The characterization of FTIR showed that pectin membranes have carboxyl and hydroxyl active groups. The results showed that the optimum condition of the adsorption process of methylene blue dye was within pH 4 with adsorption capacity of 0.75 mg/g and 60 minutes of contact time with adsorption capacity 17.64 mg/g. The optimum adsorption capacity of pectin membranes in adsorbing methylene blue was 19.39 mg /g
Implementation of Green Chemistry-Based Electrolysis Learning Media to Develop Higher Order Thinking Ability
Authors: Subarkah C Z , Trisnawati A , Sundari C D D , Malik A
Published: August 2020

In this paper, a green chemistry-based microscale kit and worksheets were made and implemented to develop higher-order thinking ability of students on electrolysis concept. The method used in this research was an experimental method with one-shot case study model implemented to the second-semester chemistry education students studying electrolysis. The ability to think at higher level, i.e. ability to analyze, evaluate, and create, were measured by referring to the revised Bloom taxonomy. The results showed that the average score achieved was 77 (categorize as good) for the ability to analyze, 82 (categorize as excellent) for the ability to evaluate, and 76 (categorize as good) for the ability to create. The as made learning media in the form of micro-scale kit and worksheet were able to develop higher-order thinking ability.
Mental Model of Prospective Teachers on Structure and Properties Correlation of Organic Compounds
Authors: Suja I W , Redhana I W , Sudria I B N
Published: August 2020

This study aims to determine the profile of prospective teachers’ mental models on the correlation of structure and properties of organic compounds before and after learning by implementing the TripleChem learning model. Subjects were students of the Chemistry Education Department of Ganesha University of Education, who are taking courses in Organic Chemistry I in 2018/2019. The subjects of the study were 22 people. Data were collected through two tier achievement test, consists content part (multiple choice) and reason (description). The data were analyzed descriptively. The results showed the mental models of prospective teachers before learning only 1.36% classified as a conceptual model. After learning by implementing TripleChem learning models, conceptual models increased to reach 62.73%. The students’ alternative mental models before and after the study, including specific misconceptions (21.82% and 8.64%), and partially correct (31.36% and 28.64%). The data show that the TripleChem learning model can construct chemistry mental model of prospective teachers on the correlation of structure and properties of organic compounds.
Analysis of Student Chemistry Learning Difficulties on Buffer Solution at SMA Negeri 2 Banjar Buleleng Bali
Authors: Sanjiwani N L I , Muderawan I W , Sudiana I K
Published: August 2020

This research aims to describe and explain students’ learning difficulties in chemistry, the distribution of students’ learning difficulties, and the causative factors of students’ learning difficulties to understand the topic of buffer solution at SMA Negeri 2 Banjar. The data sources for this research were 154 students from all class XI MIA and one chemistry teacher at SMA Negeri 2 Banjar Buleleng Bali. The research method used a quantitative and qualitative method. Quantitative methods are used to collect data on student learning difficulties by using tests and the factors that cause learning difficulties using a questionnaire, while qualitative methods are used to collect data on factors that cause learning difficulties using observation and interview guidelines. Data were analyzed descriptively by grouping students’ learning difficulties into five types includes not difficult, less difficult, quite difficult, difficult, and very difficult. The result of this research showed that students have a difficulty in learning chemistry to understand of buffer solution topic. (1) The students’ learning difficulties on buffer solution topic was ranged between less difficult until very difficult. (2) The distribution and level of student learning difficulties in indicators explaining the definition of buffer solution, analyzing the constituent components of buffer solution, determining buffer and non-buffer solution, calculating pH of acid and base buffer solution, calculating pH of a buffer solution by adding few amount of acid or base or dilution, and explaining the function of buffer solution in the body of living creatures, are difficult enough (44,97%), difficult (74,57%), less difficult (31,66%), difficult enough (43,51%), very difficult (81,82%), and difficult enough (36,36%), respectively. (3) Internal factor that caused learning difficulties is less understanding toward supporting concepts of buffer solution topics and buffer solution concept, the lack of student’s ability in mathematics, less learning interest and motivation toward chemistry. The external factor that caused learning difficulties is teacher’s teaching method, negative effect from friend at the same age, and less conducive learning conditions and times.
Antibacterial and Toxicity Activities Itchy Leaves (Laportea decumana, Roxb. Wedd) Extract
Authors: Simaremare E S , Gunawan E , Yarangga I , Satya M D , Yabansabra Y R
Published: August 2020

Itchy leaves or stingging nettle have been used as medicinal plants in various countries even in Indonesia. Papuans useLaportea decumana(Roxb)Weddas traditional medicines for local people as an anti-fatigue, anti-stiff and anti-fatigue drug. The purpose of this study was to determine the antibacterial and toxicity of theL. decumanafraction. Samples were taken from Waibron and Serui, Papua Indonesia. The samples were determined at the Center for Biodiversity Development, Papua State University, Manokwari, West Papua.L. decumanaleaf was made in the powder of simplicia, extracted with ethanol then fractionated using three solvents namely n-hexane, ethyl acetate, and ethanol. Extracts and fractions were tested for antibacterial against bacteria and cytotoxics test. The results showed that theL. decumanafraction had activity antibacterial forE. coliandS. aureusbacteria.. The toxicity test showed that fraction n-hexane and ethyl acetate was toxic while ethanol was not toxic.
The Utilization Of Useful Plant Species Based On Socio-Cultural Of Tenganan Pegringsingan Bali Aga Village, District Of Karangasem, Bali
Authors: Wijana Nyoman , Gusti Agung Nyoman Setiawan I
Published: August 2020

The purposes of this research were to know the composition of useful plant species and their utilization by the community based on socio cultural of Tenganan Pegringsingan Bali Aga Village. This research was an explorative research. The location of this research was in Bukit Kangin, Tenganan Pengringsingan Village, District of Karangasem. There were two kinds of population in this research; they were the plant vegetation and the community of Tenganan Pegringsingan Village. The plant vegetation was all of the plant species in the forest area of Bukit Kangin. Meanwhile, the social culture population was all of the Tenganan Pegringsingan people. The vegetation samples of this research were all the plant species covered by the 100 squares with size 20×20 m2. Meanwhile, the social culture samples were: The Village Officials (5 pax), The Traditional Village Officials (5 pax), The Community Figures (10 pax), Shamans (2 pax), Offering Artisan (2 pax), and The General Community Members (20 pax). The total sample were 44 persons. The data retrieval of this study was using square method. The square placement was done by using systematic sampling technique [11], [12], [13], [14] [15]. The interview, observation and questionnaires were used to retrieve socio-cultural data [16], [17]. Furthermore, the data were analized descriptively. The results of this research were: 1) There were 77 plants species in Bukit Kangin, Tenganan Pegringsingan Village, Sub-District of Manggis, District of Karangasem. Those 77 species on the data were included into 40 families with total of 2.574 individuals; 2) There were 46 species out of the 77 plant species in Bukit Kangin classified as useful for religious offerings (Hindu), medications, food, housing, clothing and industrial needs. For more detail of their utilization, it can be summarized as follows: for religious offerings (Hindu) there were 29 plants species (35.80%), for medications there were 18 plants species (27.70%), for food there were 17 plants species (20.99%), for housing there were 13 plants species (16.05%), for clothing and industrial needs there were 2 plants species; and 3) Based on the category of the plant organs/parts utilization can be summarized as follow leaves utilization were 23 plants species (32.40%), stem utilization were 18 plants species (25.35%), fruits utilization were 22 species (30.99%), flowers utilization were 4 species (5.64%), roots and seeds utilization were 2 plant species (2.81%). It could be recommended a further more specific and in-depth study on the utilization of those plant species is needed to be done.
Conflicting Or Synergistic Interaction Between Tourism And Marine Protected Areas In Lembongan Island
Authors: Prasetia I N D , Supriharyono  , Anggoro S , Sya’rani L
Published: August 2020

Lembongan Island designted as marine protected areas with the Decree of the Minister of Marine Affairs and Fisheries of the Republic of Indonesia Number 24 concerning the Nusa Penida Marine Protected Area of Klungkung Regency in the Province of Bali in 2014. The conservation area is utilized for marine tourism, sustainable fishery, environmentally-friendly aquaculture, social economics research and development, and other sustainable marine resources utilization. Lembongan Island has coral reefs, mangrove forests, white sand, and beaches are a major attraction for tourists. An increase in the number of tourist visits has a direct or indirect impact on coral reef ecosystems. This study aims to determine the relationship between tourism activities and coral reef ecosystems. the study was conducted on Lembongan Island from 2015 to 2018. The study used the manta tow survey method, line itercept transect, questionnaires, interviews and analyzed using SWOT. Research shows that tourism activities have the effect of reducing the quantity and quality of coral reef ecosystems. Co-management of coral reef management by involving all stakeholders can minimize the decline in the quantity and quality of coral reef ecosystems.
Roles Model Of Teachers In Facilitating Students Learning Viewed From Constructivist Theories Of Learning
Authors: Subagia I W
Published: August 2020

Human learning has been understood as a complex process because human learning involves not only physical senses, but also cognitive processes. This paper aimed at describing and explaining teacher’s role model in facilitating students learning. The description and explanation were developed based on constructivist learning theories which explains learning as the process of construction of knowledge by individual student or learner in respond to new learning experiences. The discussion results described three different roles of teacher in conjunction to the characteristics of students’ response in learning process. The characteristic of students can be classified into three, namely excited students, unresponsive students, and struggled students. The roles of the teacher in respond to the characteristic of the students are as a learning supporter for excited students, as a learning motivator for unresponsive students, and as a learning model for struggled students. These roles facilitate all students to learn joyfully and meaningfully through cycles of learning involving assimilation, accommodation, and equilibration processes.
Effective production of multifunctional magnetic-sensitive biomaterial by an extrusion-based additive manufacturing technique
Authors: Rodrigues A F M , Torres P M C , Barros M J S , Presa R , Ribeiro N , Abrantes J C C , Belo J H , Amaral J S , Amaral V S , Bañobre-López M , Bettencourt A , Sousa A , Olhero S M
Published: August 2020

A calcium phosphate (CaP)-based scaffold used as synthetic bone grafts, which smartly combines precise dimensions, controlled porosity and therapeutic functions, presents benefits beyond those offered by conventional practices, although its fabrication is still a challenge. The sintering step normally required to improve the strength of the ceramic scaffolds precludes the addition of any biomolecules or functional particles before this stage.

This study presents a proof of concept of multifunctional CaP-based scaffolds, fabricated by additive manufacturing from an innovative ink composition, with potential for bone regeneration, cancer treatment by local magnetic hyperthermia and drug delivery platforms. Highly loaded inks comprising iron-doped hydroxyapatite and β-tricalcium phosphate powders suspended in a chitosan-based solution, in the presence of levofloxacin (LEV) as model drug and magnetic nanoparticles (MNP), were developed. The sintering step was removed from the production process, and the integrity of the printed scaffolds was assured by the polymerization capacity of the ink composite, using genipin as a crosslinking agent. The effects of MNP and LEV on the inks’ rheological properties, as well as on the mechanical and structural behaviour of non-doped and iron-doped scaffolds, were evaluated. Magnetic and magneto-thermal response, drug delivery and biological performance, such as cell proliferation in the absence and presence of an applied magnetic field, were also assessed. The addition of a constant amount of MNP in the iron-doped and non-doped CaP-based inks enhances their magnetic response and induction heating, with these effects more pronounced for the iron-doped CaP-based ink. These results suggest a synergistic effect between the iron-doped CaP-based powders and the MNP due to ferro/ferrimagnetic interactions. Furthermore, the iron presence enhances human mesenchymal stem cell metabolic activity and proliferation.