bluuebunny/crossref_metadata_2025 huggingface dataset:
High enhancement factor of SERS probe based on silver nano-structures deposited on a silica microsphere by laser-assisted photochemical method
Authors: Bui Huy , Nguyen Thuy Van , Pham Thanh Son , Pham Van Hoi , Pham Thanh Binh
Published: August 2020

The high enhancement factor (EF) of surface-enhanced Raman (SERS) probes is an important parameter for high-sensitivity Raman scattering measurement applied to environment control. In this article, we present a SERS probe based on silver nano-structures deposited on silica microsphere surfaces made by the laser-assisted photochemical method and reflection converging mirror for a high EF Raman measurement of ultralow organic compound concentration inliquid environments. The laser-assisted photochemical method can synthesize and homogeneously deposit nano-silvers on a silica microsphere, and the reflection converging mirror can collect more Raman signal to the photo-detector and give high Raman enhancement of the SERS probe. The SERS-activity of the probe is verified by the detection of ultralow concentrations of Rhodamine 6 G in aqueous solutions in the range of 10−4–10−10 M. The obtained results show that the proposed SERS probe has an increase of collected Raman intensity up to 32% in comparison to a SERS probe without reflection converging mirror, and an EF of the SERS probe achieved up to 1.8 × 1010. We believe that the novel SERS probe has a large potential for applications in biochemical sensing techniques.
Molecular dynamics simulation of the interactions between screw dislocation and stacking fault tetrahedron in Fe–10Ni–20Cr and Ni
Authors: Chen Xiaoping , He Xinfu , Chen Yangchun , Jia Lixia , Yang Wen , Hu Wangyu , Gao Fei , Deng Huiqiu
Published: August 2020

Radiation-induced defects are the significant cause of radiation damage in austenitic stainless steels. In this work, the interactions between a screw dislocation and stacking fault tetrahedrons (SFTs) are studied in Fe–10Ni–20Cr (a model alloy of austenitic stainless steel) and Ni, using molecular dynamics simulations. Four interaction processes were primarily found, including (1) partial absorption, (2) sheared, (3) bypassing, and (4) restored through double cross-slip. In Fe–10Ni–20Cr alloys, there is almost no correlation between the critical resolved shear stress (CRSS) value and SFT size, but the intersection position largely impacts the results. And the CRSS value decreases with temperature increasing in Fe–10Ni–20Cr. The occurrence of cross-slip has a significant effect on the interactions, and there exist greater CRSS value in the interactions of cross-slipping. Besides, the occurrence of the cross-slip is linked to the stacking fault energy and the distribution of solute atoms of the alloys.
Kerr effect anomaly in magnetic topological insulator superlattices
Authors: Liu Jieyi , Singh Angadjit , Kuerbanjiang Balati , Barnes Crispin H W , Hesjedal Thorsten
Published: August 2020

We report the magneto-optical Kerr effect (MOKE) study of magnetic topological insulator superlattice films with alternating transition-metal and rare-earth doping. We observe an unexpected hump in the MOKE hysteresis loops upon magnetization reversal at low temperatures, reminiscent of the topological Hall effect (THE) reported in transport measurements. The THE is commonly associated with the existence of magnetic skyrmions, i.e. chiral spin textures originating from topological defects in real space. Here, the observation of the effect is tied to ferromagnetic ordering in the rare-earth-doped layers of the superlattice. Our study may provide a new approach for the non-invasive optical investigation of skyrmions in magnetic films, complementary to electrical transport measurements, where the topological Hall signal is often the only hint of non-trivial magnetization patterns.
An electrochemical DNA biosensor fabricated from graphene decorated with graphitic nanospheres
Authors: Raja Jamaluddin Raja Zaidatul Akhmar , Tan Ling Ling , Chong Kwok Feng , Heng Lee Yook
Published: August 2020

Graphene decorated with graphitic nanospheres functionalized with pyrene butyric acid (PBA) is used for the first time to fabricate a DNA biosensor. The electrode was formed by attaching a DNA probe onto PBA, which had been stacked onto a graphene material decorated with graphene nanospheres (GNSs). The nanomaterial was drop-coated onto a carbon screen-printed electrode (SPE) to create the GNS-PBA modified electrode (GNS-PBA/SPE). A simple method was used to produce GNS by annealing graphene oxide (GO) solution at high temperature. Field emission scanning electron micrographs confirmed the presence of a spherical shape of GNS with a diameter range of 40–80 nm. A stable and uniform PBA-modified GNS (GNS-PBA) was obtained with a facile ultrasonication step. Thus allowing aminated DNA probes of genetically modified (GM) soybean to be attached to the nanomaterials to form the DNA biosensor. The GNS-PBA/SPE exhibited excellent electrical conductivity via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) tests using potassium ferricyanide (K3[Fe(CN)6]) as the electroactive probe. By employing an anthraquinone monosulfonic acid (AQMS) redox intercalator as the DNA hybridization indicator, the biosensor response was evaluated using the DPV electrochemical method. A good linear relationship between AQMS oxidation peak current and target DNA concentrations from 1.0 × 10−16to 1.0 × 10−8M with a limit of detection (LOD) of less than 1.0 × 10−16M was obtained. Selectivity experiments revealed that the voltammetric GM DNA biosensor could discriminate complementary sequences of GM soybean from non-complementary sequences and hence good recoveries were obtained for real GM soybean sample analysis. The main advantage of using GNS is an improvement of the DNA biosensor analytical performance.
Disentangling dark and luminous phases of nanosecond discharges developing in liquid water
Authors: Šimek Milan , Hoffer Petr , Prukner Václav , Schmidt Jiří
Published: August 2020

There is no clear experimental evidence of the underlying microscopic physical mechanisms of micro-discharges directly produced in liquids. In this study, we examine shadowgraph images and plasma-induced emission (PIE) to decouple simultaneously developing dark and luminous phases of micro-discharges with nanosecond durations in liquid water. We apply diagnostics with extremely high temporal (down to 30 ps) and spatial (down to 1 μm) resolutions to capture tiny bush-like dark filaments that expand from the anode tip together with the formation of luminous tree-like structures. For the first time, we disentangle two closely coupled dark and luminous phases of the discharge events and determine their onsets accurately with respect to the driving high-voltage (HV) pulse. The dark filaments start appearing within ∼3–4 ns after the onset of the HV pulse, and subsequently expand at a constant velocity of ∼1 × 105–2 × 105 m s−1, depending on the HV amplitude and anode curvature. A systematic analysis of the PIE waveforms using the associated shadowgraph images reveals that the onset of the luminous discharge phase is delayed by ∼600–800 ps with respect to the onset of the initial dark filament structures. Considering the constant propagation velocity of dark filaments, the luminous phase starts to develop when the extension of regions with a perturbed refractive index (i.e., perturbed density) reaches several tens of micrometres. An analysis of PIE tracks within the captured shadowgraph images confirms that luminous filaments develop only in regions affected by primary dark filaments and their attachment to the anode surface coincides with points of initial onset of the first dark filaments. Furthermore, the emission intensity produced during the luminous phase originates from the luminous filaments developing in the bulk liquid. Our study provides an important insight into the dynamics of different phases of micro-discharges in de-ionised water.
On uniformity and non-local transport in low pressure capacitively coupled plasmas
Authors: Rauf Shahid
Published: August 2020

Low pressure (<30 mTorr) capacitively coupled plasmas (CCP) are important for many plasma processing applications. Due to high energy of electrons in these plasmas and long electron mean free path, kinetic phenomena dominate the electron behavior. A multi-dimensional particle-in-cell (PIC) model is utilized to study the physics of sub-100 mTorr Ar CCPs in this article. A one-dimensional model for helium plasma in the 30–300 mTorr pressure range is first used to benchmark the PIC code against published results by Turner et al [2013 Phys. Plasmas 013507]. The article then focuses on two-dimensional modeling of the gaseous electronics conference (GEC) reference cell in cylindrical geometry. Computed ion density and DC bias voltage at 100 mTorr are compared to available experimental data for a range of radio frequency voltages, demonstrating good agreement. The validated model is used to examine Ar plasmas in the GEC reference cell in the 12.5–100 mTorr pressure range. It is found that the peak in ion and electron densities is near the electrode edge at 100 mTorr due to strong electric field there. As the gas pressure decreases, the peak in plasma density moves to the chamber center. This change in plasma spatial profile is linked to kinetic behavior of electrons, both regarding plasma production and transport in the plasma. Time-dependent results are used to illustrate that electron current at 25 mTorr is mainly kinetic and carried by beam electrons generated by expanding sheaths.
Forecasting Farmer Exchange Rate in Bali Province Using Seasonal Autoregressive Integrated Moving Average (SARIMA) Method
Authors: Pratiwi Dinda , Agustini Sisilia M.U. , Windasari Wiwin , Kencana Eka N.
Published: August 2020

Farmer’s exchange rate (FER) is a proxy indicator to value the farmer’s purchasing rate and shows the term of trade between agricultural products and services sold and the goods purchased by farmers in producing and consuming households. FER obtained by comparing the Farmer Received Price Index with the Farmer Paid Price Index both expressed as percentages. The purpose of this study is to predict the FER of Bali Province from May 2019 to December 2019 and to count the level of purchasing power of the farmers. The monthly data of FER from January 2010 to April 2019 were used to build a seasonal ARIMA (SARIMA). Four models i.e. SARIMA(0, 1, 3), SARIMA(3,1, 0), SARIMA(4,1,0), and SARIMA(1,1, 1) with seasonal factor (0,1, 1)12 were tested. Referring AIC value for SARIMA(0,1,3) as much as 326.94 is the lowest then we inferred this model is the best SARIMA model to predict the FER of Bali Province. Our research concludes the farmer’s income increases more than their expenditures.
Dynamical behavior of leukemic cells with chemotherapy in acute myeloid leukemia
Authors: Ari Adi Yudi , Purwadi Joko
Published: August 2020

In this paper, we consider a mathematical model for the study of the interaction between leukemia cells and chemotherapeutic drug in Acute Myeloid Leukemia (AML). In our model, there are three compartments, namely, leukemia-initiating cells, leukemics blast, and chemotherapeutic drug. Using a stability theory of differential equation, we analyze the existence and stability of the system at various equilibrium points. Furthermore, we discuss the effect of leukemia treatment by varying the values of relevant parameters. We also provide numerical simulations to illustrate the theoretical results.
On Magic and Antimagic Total Labelings of Graphs
Authors: Ngurah A A G
Published: August 2020

LetGbe a super edge-magic total graph of orderpand sizeq. It is shown that the graphGis a super (a, 1)-antimagic total graph, ifqis odd. It is also shown that ifq=porq=p- 1 thenGis an (a,d)-antimagic total graph for some positive integersaandd. Base on these results, we produce new classes of (super) (a,d)-antimagic 2-regular graphs from known super edge-magic total 2-regular graphs.
Improvement a positive attitude towards abstract algebra through APOS theory approach
Authors: Arnawa I M , Yanita  , Ginting B , Yerizon  , Nita S
Published: August 2020

Rate of students’ participation in teaching and learning Abstract Algebra (AA) depends upon attitude towards AA and Students’ success in AA depends upon rate of students’ participation in teaching and learning of AA. Thus it is very important to improve students’ attitude towards AA. This research was pre-experimental one shot case study design. The subject of this study were 50 students who participating in the AA course academic year 2018/2019 at Andalas University. A questionnaire was used to examine student’s attitudes towards AA and its learning. Descriptive statistics and t-test with level of significance α = 0.05 were used for data analysis. The results showed that: (1) APOS theory approach can improve students attitude towards AA and its learning (2) There was no a gender gap in students’ attitude towards AA and its learning. (3). There was a positive correlation between attitude towards AA and its learning.
The Influence of Inquiry Learning Method Aided by Open Ended Worksheet Towards Quantitative Reasoning and Self-Esteem
Authors: Arisujati N W , Sariyasa  , Suweken G
Published: August 2020

Problem solving plays an important role in mathematics and should have a prominent role in mathematics education. Some factors that affect students’ problem-solving ability are quantitative reasoning and self-esteem. The general objective of this research aims to compare quantitative reasoning and self-esteem of students who were taught using inquiry learning with open ended worksheet and those who were taught using conventional learning. This research used quasi-experiment approach with randomize posttest-only control group design. The population of this study consisted of 255 seventh grade students in Singaraja. In addition, cluster random sampling was used to get two groups. The experimental group was taught using inquiry learning method with open ended worksheet and the control group was taught using conventional learning. The data was collected using test and non-test technique then analyzed using Manova. The results showed that quantitative reasoning and self-esteem of students who were taught using inquiry learning model with open ended worksheet were better than students who were taught using conventional learning model. Inquiry learning model with open ended worksheet give students more chance to explore their thinking and idea in solving problem. This model contributes in the improvement of students’ capabilities in quantitative reasoning and self-esteem.
The Effect of Online Discussion in Blended Learning on Students’ Mathematical Concept Comprehension and Attitude
Authors: Yulia Prawestri Putu , Gusti Putu Sudiarta I , Wayan Puja Astawa I
Published: August 2020

This research aimed at (1) investigating if asynchronous online discussion in Blended Learning (BL) affect positively on students’ concept comprehension and attitude, as well as (2) describing why asynchronous online discussion in BL is better at improving students’ concept comprehension and attitude. This research combined quantitative and qualitative research utilizing explanatory sequential design. The quantitative design with Randomized Posttest-Only Comparison Group Design with a sample of 68 junior high school students in Bali, the qualitative design used descriptive approach on five population subjects which was done purposively. The quantitative data in the form of students’ concept comprehension and attitude was collected by using essay test and questionnaire. The qualitative data was in the form of: (a) students’ responses towards the implementation of online discussion, (b) online and group discussion activities, (c) students’ works, collected by using (a) interview, (b) observation sheet, (c) documentation. The quantitative data was analysed by using Manova test with 5% significance level. The qualitative data was analysed in the steps of: (a) data reduction, (b) data presentation, and (c) data verification. The result of the experiment showed that the concept comprehension and attitude of the students who attended asynchronous online discussion in BL was significantly better than the students who attended synchronous online discussion in BL. This was because the students who attended asynchronous online discussion were more enthusiast, more trained in communicating their understanding, more motivated in discussion and in learning process.
Why should you reverse the order when dividing a fraction? A study of pre-service mathematics teachers’ pedagogical content knowledge in fractional concept
Authors: Apsari R A , Sariyasa S , Indrawan G , Maulyda M A , Radiusman Radiusman
Published: August 2020

This study was a part of larger study in examining pre-service mathematics teachers’ Pedagogical Content Knowledge. The aim of the present study was to elaborate the prospective teachers’ conceptual understanding in fraction and how they will teach it for the students. There were 50 participants in this study, all of them are the final year students of mathematics education study program of a state university in Bali who already took the teaching internship program in the school. The data were collected through written test and continued by interview with the participants. The data were analysed qualitatively using descriptive method. From the result, it is found that the prospective mathematics teachers have a difficulties in understanding the concept of fraction. It leads to the lack comprehension in teaching the concept to the students. Reflect to the result, it is recommended to the teacher training institution to emphasize the big ideas in school mathematics’ topics to ensure the prospective teachers have a sufficient knowledge to teach mathematics meaningfully.
Development Content and Online Discussion Strategy in Blended Learning to Improve Student Mathematical Learning Outcomes
Authors: Patni L D P , Sudiarta I G P , Suparta I N
Published: August 2020

Content and strategies online discussion have an important role in blended learning, but the content and strategies currently implemented have not been able to contribute optimally. This study aims to identify the characteristics of content and the application of online discussion strategy and describe their quality in terms of validity, practicality, and effectiveness as means to improve students mathematics learning outcomes. This research is a developmental research with Design Based Research approach. The subject of this research were students of VIII SMP Negeri 1 Mengwi in academic year 2018/2019. Learning outcomes data collected in the form of data understanding students’ mathematical concepts and student attitudes in learning mathematics. The data were analyzed descriptively. This research produce blended learning content that meets valid, practical and effective criteria. The content has the following characteristics : 1) Text, containing a summary of the material and focuses on the ability of students to construct their own knowledge. 2) Interactive media, being able to actively involve students in learning abstract concepts with the helping of illustrations and visualization. 3)Video links, helping students improve their mathematical skills such as the ability to decrease formulas. 4) Exercises, containing variations in the types of questions and giving students instant feedback. This research also resulted in effective online discussion strategy with the following steps : seting goals for online discussion, preparing role for online discussion, preparing content that facilitates students to learn independently, motivating students to have the confidence to hold discussions, involving teachers to moderate discussions, implementing reward and punishment by giving points and additional tasks respectively to increase positive competitiveness, evaluating by giving online quizzes. Learning outcomes obtained by students have increased, 79.70 in first try out and 82.76 in second try out. Thus, it can be concluded that the quality of content and online discussion strategy have an important role in improving student mathematics learning outcomes.
Criticality Analysis of Thorium Element (ThO2) Insertion at Various Location in the Kartini Reactor Core
Authors: Salam Mahrus , Syarip
Published: August 2020

The criticality analysis of Kartini reactor by inserting of thorium element contained in ThO2 has been done. The main objective of this research was to observe the effect of thorium element insertion to the criticality level of Kartini reactor. The analysis method was a neutronic computation using MCNP computer code. The criticality analysis was performed by inserting a thorium element of several different masses at several locations in the reactor core. The analyses were performed for the insertion of ThO2 at several different positions from ring B to ring F of the reactor core. The result showed that in the general, by inserting the thorium elements on the reactor core would generate a smaller k-inf. It was because thorium would produce a negative reactivity in the reactor core. This analysis result showed that the reactor is on the subcritical level (k-eff. < 1) when 3000 g of ThO2 was inserted in the ring B, C and D. Meanwhile, it still on the critical level (k-eff. ∼ 1) when ThO2 element was inserted in the ring E and F. However, to ensure the safety of the Kartini reactor during this experiment, it was necessary to calculate the shutdown margin (SDM) and also radial power peaking factor. The analysis showed that the calculated SDM was 2.5$ and the radial power peaking factor was 1.5. These values still meet the required value for the Kartini reactor i.e. SDM should be higher than 0.5$ and the radial power peaking factor should be lower than 1.75.
Zero gravity of free-surface flow under a sluice gate
Authors: Wiryanto L.H.
Published: August 2020

Free surface flow is a classical problem in hydrodynamics, such as flow under a sluice gate. The ratio between the uniform depth at far downstream and the height of the gate, called contraction coefficient, is important in building the sluice gate. In this report, that number is calculated based on a model of potential flow, without involving gravity. A conformal mapping and defining an analytical function can are the main mathematical problem that should be done, before solving the model. Here, we mainly determine the coordinates of the free surface of thow from the gate, they are calculated by integral form, and at far downstream we obtain the fluid depth as used to calculate the contraction coefficient, i.e. 0.611.
Antibacterial evaluation of 2,4-dihidroxy benzoic acid on Escherichia coli and Vibrio alginolyticus
Authors: Ngurah Budiana I Gusti M. , Ni Nyoman Yuliani , Dafroyati Yuliana , Gede Aris Gunadi I , Taneo Malkisedek
Published: August 2020

In recent years, human pathogenic microorganisms have developed resistance in response to the indiscriminate use of commercial antimicrobial drugs commonly employed in the treatment of infectious diseases. Therefore, research to discover the new anti-bacterial compounds is important to do. This study was carried out with an objective to synthesis and invaluated the antibacterial potentials of 2,4-dihidroxy benzoic acid. The aim of the study is to synthesis and assess the antimicrobial activity and to determine the zone of inhibition of on Escherichia coli and Vibrio alginolyticus. The synthesis of 2,4-dihidroxy benzoic acid was conducted by reacting 2,4-dihidroxy benzene and carbon dioxide. The characterization of the target compounds was performed by IR and MS spectrometers. The growth of the tested bacteria was observed using a colony counter to see the diameter of the resistance which was caused by the test solution. The antibacterial activity test indicated that 2,4-dihidroxy benzoic acid had the potential as an antibacterial against Escherichia coli and Vibrio alginolyticus. The synthesis product was obtained as a white solid, melting point 168-169 °C, 67.5 % yield and 97.5 % purity. The activity was known from its inhibition zone. At the concentration of 100 ppm, 2,4-dihidroxy benzoic acid solution showed the diameter of the inhibitory zone was 17.8 mm and 17.0 mm respectively, while amoxicillin antibiotic showed of 16.6 mm. These results indicate that 2,4-dihidroxy benzoic acid have a greater strength than amoxicillin in inhibiting bacterial growth Escherichia coli and Vibrio alginolyticus.
Development of Green Chemistry Learning Book to Improve Students’ Learning Outcomes
Authors: Sri Wulan I D A , Redhana I W , Adnyana P B
Published: August 2020

This study aimed to produce a green chemistry learning book to improve students’ learning outcome. Type of study was a research and development by adopting the Thiagarajan model. The stages of this study included (1) define phase including front-end analysis, students’ analysis, task analysis, concept analysis, and specifying instructional obejctive, (2) design phase including preparation of syllabus, lesson plan and the green chemistry learning, (3) develop stage including testing of validity, practicality and effectivy of the green chemistry learning book. The data in this study were analyzed using descriptive statistical analysis techniques. Data analysis result obtained in this study were need analysis data of teacher and student, the characteristics of learning book, validity, practicality and effectiveness data of learning book. The results of the study indicated that (1) the characteristics of the learning book which were developed included the presentation of the dangers of synthetic chemicals, the prevention of the use of synthetic chemicals, and the substitution of synthetic chemicals with environmentally friendly materials, (2) learning book developed had valid, practical and effective categories. The learning book could be applied to improve students’ learning outcome.
Students’ Mental Models in Acid-Base Topic Based on Gender
Authors: Putriani V D , Redhana I W , Maryam S
Published: August 2020

This study aimed to describe differences of student’s mental models based on gender and the factors influencing the student’s mental models in understanding acid-base topic. The study was a survey research. The population consisted of 279 students of 11th-grade of Mathematics and Natural Sciences Classes of SMA Negeri 1 Singaraja in Buleleng Bali at an academic year of 2018/2019. In this study, all members of the population became members of the sample. The data needed in this study were the student’s mental model scores and factor that influence student’s mental model. Data were collected using a diagnostic test and questionnaire. Data were analysing descriptively by grouping student’s mental models based on gender and factors that influence student’s mental model. The results showed that there was no significant difference in student’s mental model based on gender. In addition, most of the factors that influence student’s mental model were the internal and external factors.
Macronutrients Level And Total of Bacteria From Combination of Banana Stems And Coconut Fibers With MA-11 As Bioactivator
Authors: Suryanti I A P , Santiasa I M P A
Published: August 2020

The purposes of this research were to determine the maximum macronutrients content of C, N, P, K and the total of bacteria from combination of banana (Musa paradisiaca) stems, and coconut fibers that is using local microorganism MA-11 as a bioactivator. The combination includes Combination 1 (K1): 250 grams of banana stems and 250 grams of coconut fiber; Combination 2 (K2): 375 grams of banana stems and 125 grams of coconut fiber; Combination 3 (K3): 125 grams of banana stem and 375 grams of coconut fiber. Each combination added 1 liter of coconut water, 125 grams of sugar and 125 ml of MOL MA-11 which was fermented for 7 days. The contents of C, P and K in liquid organic fertilizer were determined by using a spectrophotometer, while N levels were determined using semi micro kjeldahl. The number of bacteria in each combination is calculated using the total count method. The results showed that the higest of total Carbon (C) was found in combination 1 (K1) of liquid organic fertilizer, namely 14.35%. The maximum macronutrients N, P and K are found in the combination 3 (K3), respectively 2.48 % (N), 0.66 % (P) and 2.19 % (K). The highest total count of bacterial was found in combination 3 (K3) was 8.2 x 107 cfu/ml.
The Effectiveness of the Think Pair Share Model Based on Questions to Improve Students’ Participation and Students’ Learning Outcomes about Histology Structure of Digestive System
Authors: Citrawathi D M , Widiyanti N P M , Adnyana P B
Published: August 2020

This study aimed to determine the effectiveness of Think Pair Share learning based on questions models to increase students’ participation and learning outcomes in studies of the histological structure of the digestive system. To achieve these objectives, research was conducted on the Biology study program at the Faculty of Mathematics and Natural Sciences, Ganesha University of Education. Research sample was the second semester students, amount of 17 students. The design of this study was one short case study. Instruments used in this study included questionnaires and observation sheets to assess students’ participation and responses in learning, and knowledge tests to assess student cognitive learning outcomes. The results obtained by the value of students’ participation were 47.1% in the good category and 47.1% in the very good category with an average value of 83.12. Cognitive learning outcomes obtained a mean value of 76.0. Students who got a greater or equal value of 70.0 were 76.5%. The conclusion of this research were that the Think Pair Share Learning model based on questions could increase students’ participation and learning outcomes in the study of the Histological Structure of the Digestive System.
The Effect of Digital Literacy on the Ability of Teachers to Develop HOTS-based Assessment
Authors: Wayan Widana I
Published: August 2020

Digital literacy and the ability to develop HOTS-based assessment are important competencies for teachers in industrial revolution 4.0. The purpose of this research is to determine the effect of digital literacy on the ability of teachers to develop HOTS-based assessment. This study is survey research. The population is senior high school and vocational high school mathematics teachers in Bali, West Nusa Tenggara, and East Nusa Tenggara provinces. Multistage random sampling technique is applied. The data is collected by using a questionnaire. It is analysed by using simple regression analysis methods. Data processing is carried out by using the SPSS 23.0 program with a significance level of alpha = 0.05. The results of data analysis show a value of F = 60.594 with a significance value 0.000 which means that digital literacy has a significant effect on the ability of teachers to develop HOTS-based assessment. The magnitude of the digital literacy influence on the ability of teachers to develop HOTS-based assessment is 13.2%. Thus, the ability of teachers to develop HOTS-based assessment can be influenced by other factors of 86.8%. The recommendation proposed is that further research is needed to reveal other variables that contribute on the ability of teachers to develop HOTS-based assessment.
Profiles of Environmental Literacy of Senior High School Students
Authors: Redhana I W , Suardana I N , Selamat I N
Published: August 2020

This study aimed to describe the environmental literacy of high school students in Bali Province, Indonesia. For that reason, the study conducted was survey research. The population of the study was high school students in the Bali Province, Indonesia. Population of the study was 40.608 students. Samples were drawn by a multistage random sampling technique. Each district was chosen 50 students randomly. Thus, there were a total of 450 students as research samples. The research samples consisted of the tenth, eleventh, and twelfth-grade students, each of which amounted to 131, 263, and 56 people and the number of male and female students was 151 and 299 people, respectively. Students’ environmental literacy data were collected with an environmental literacy inventory developed by researchers. This inventory consisted of five dimensions, including knowledge (15 items), concern (15 items), sensitivity (16 items), attitude (9 items), and behavior (8 items) towards the environment. Inventory is created in Google forms and circulated online. The data obtained in this study were analyzed by calculating the average score of environmental literacy and then changed from a scale of 5 to a scale of 100, then grouped into the categories of very low (0 - 20%), low (21 - 40%), moderate (41 - 60%), high (61 - 80%), and very high (81 - 100%). The results showed that overall the environmental literacy of students was classified as a high category. However, the dimension of knowledge was in the medium category, while the other dimensions were in the high category.
The role of families and school environments on juvenile delinquency in Denpasar City: A quantitative approach
Authors: Kencana Eka N , Tastrawati Tari , Jayanegara Ketut
Published: August 2020

Adolescence is a transition period from children to adults with its characters are (a) the existence of an extension of the self; (b) the existence of self-objectification; and (c) the growth of the philosophy of life. In the transition process, an adolescent will experience a personality formation that occurs not in a simple way and has a potency for self-conflict. The existence of incompatibility between the three adolescent characteristics and the values or norms that are generally acceptable in the community has the potential to trigger an ‘emotional outburst’ for the youth if it was not properly handled by the teenager or by his/her parents and the surrounding environment. This self-conflict potentially leading to acts of irregularities, commonly refers to juvenile delinquency. This essay aims to study the effect of the socio-economic background of the family and school environment on juvenile delinquency at Denpasar City, the capital of Bali province. A hundred and fifty senior high school students at Denpasar, randomly selected as the respondents and were asked to fulfill the self-regulated questionnair´e. By applying the variance-based structural equation modeling (VB-SEM), we found the socio-economic factors have a bigger effect on juvenile delinquency than the influence of school environments.
The Effectiveness Of Learning Tools In Science Learning
Authors: Parwata K Y L , R Sudiatmika A A I A
Published: August 2020

Learning tools are thing that used to help students learn more effectively and efficiently. This study aimed to determine the effectiveness of learning tools to support the science learning process. The Subjects of this study are articles obtained through the search site https://scholar.google.co.id that relevant to the issue. There were 3 selection steps to collect articles used as the main data sources. The first selection based on the title of the article. The second selection arranged through abstract scanning. The third selection conducted by reading the entire contents of the article. Through the selections, 40 accredited articles that analyse learning tools, especially in science education (Physics 65.85%, Chemistry 4.88%, and Biology 29.27%) obtained as the data source. The articles are analysed descriptively to determine the effectiveness of using learning tools in science learning to improve student competency. The learning tools in the articles consisted of innovative tools developed (72.5%) and conventional tools available in schools (27.5%). The learning tools in the articles applied at various levels of education, from elementary school to university. Based on analysis data, the use of learning tools was 100% effective in support science learning, characterized by an increase in student competence after the use of tools in learning. Competencies that developed through the use of learning tools are knowledge (53.3%), attitude (20%), skills (18.3%), mindset (1.68%), metacognitive (1.68%), creativity (1.68%), problem-solving (1.68%), and motivation (1.68%). The benefits that reached from the use of learning tools, specifically in science lessons, have implications for improving student competency.
The Validity of Tri Hita Karana (THK) Oriented Blended Learning Tools to Improve Student’s Critical Thinking Ability
Authors: Dewi N P S R , Adnyana P B , Citrawathi D M
Published: August 2020

The aims of this study was to develop a valid Tri Hita Karana-oriented blended learning tools on anatomy and human physiology to improve students’ critical thinking in Biology. Learning tools in this study were developed using a 4D development model consisting of the following stages. 1) Define, 2) Desing, 3) Development stage, and 4) Diseminate. At present the research is at the stage of developing and validating learning tools. The validity test performed are content validity and construct validity. The content validity was carried out by finding the relevance of THK-oriented learning tools with the theory of blended learning and learning materials that were used as guidelines. The construct validity test was carried out by looking at the consistency of each component of THK-oriented learning tools with the blended learning learning characteristics obtained from the results of the validator’s assessment. Based on the validator’s assessment, the validity of the learning device in this study is classified as a very valid category. Furthermore, a limited trial is conducted to see the practicality and effectiveness of learning tools.
Texture and microstructure evolution of 321 austenitic stainless steel ultra-thin strip during asynchronous rolling
Authors: Chen Jingqi , Yang Liuqing , Hu Xianlei , Liu Xianghua
Published: August 2020

This paper studied the evolution of texture and microstructure of 321 austenitic stainless steel ultra-thin strip during asynchronous rolling. Experimental results show that during the process of asynchronous rolling, the martensitic structure mainly forms such kinds of texture, as {111} <110> Z texture, {111} <112> Y texture, {001} <110> R-CubeND texture, {112} <110> Cu texture, and {110} <110> Goss texture. With the increase of deformation, the strengths of {111} <112> Y texture, {001} <110> R-CubeND texture, {112} <110> Cu texture, and {110} <110> Goss texture increase first and then decrease. In the early stage of rolling, dislocation slip is the main plastic deformation, followed by deformation twins in the high strain region, which prevents further dislocation slip. When the rolling pressure rate is greater than 50%, the deformation induces rapid growth in the content of the martensite, with the continued nucleation and growth of the deformation twins.
Effect of sputtering power on the microstructure and photelectric properties of Al doped ZnO thin films
Authors: Li Shuli , Meng Yu , Zhang Bianlian , Cheng Zhen , Li Yuanyuan , Zhao Xiaoxia
Published: August 2020

Investigation of the doped ZnO films deposited on different substrates plays a significant role in improving the optical properties of optical components. The Si wafer and glass were used as the substrates for comparison.The effect of sputtering power on the surface morphology, microstructure, optical and electrical properties of A1 doped ZnO (AZO for short) films were studied. The results show that the AZO films prepared on different substrates with various power all have a good c-axis preferred orientation; the surface particle size of the films increase gradually with the increasing sputtering power; the resistivity decreases first and increases when the the sputtering power reached 100 W. As for the films sputtered on glass, the result show that the visible light range has a high transmittance ( >80%), the absorption side wavelength is 350-400 nm.
Application of S-doped TiO2 photocatalysts in degradation of BTEX from synthetic surfaces
Authors: Yuan Ronghui , Wu Tinghua , Hu Tianyi , Shi Li , Shi Jing
Published: August 2020

S-doped anatase TiO2 (average grain size: 20 nm) was synthesized by a hydrothermal treatment, and the crystalline phase and morphology of the as-fabricated materials were characterized with XRD, TEM, and EDX. We investigated the catalytic reactions in a simulated environment (60 L environmental chambers) in tandem with TD-GC-MS determinations. Furthermore, the photocatalytic activity of S-doped TiO2 was evaluated by monitoring the degradation of BTEX from synthetic surfaces, and maximum of 85% degradation rate exhibited for the S-doped TiO2 under visible light after irradiation for 1 h.
Effect of cryogenic-tempering treatment on the performance of high ni gear steel
Authors: Chen Xuan , Song Mingming , Liu Tao , Pu Ye , Ye Bin , Zhang Yunping
Published: August 2020

Effects of cryogenic-tempering hybrid heat treatment on the microstructure and mechanical properties of 18Cr2Ni4W gear steel after carburizing-quenching were investigated. The performances of the fully carburized and non-carburized samples were compared and analysed. The results show that the effect of cryogenic treatment on the microstructure and mechanical properties of 18Cr2Ni4W steel without carburization is negligible. The carburizing layer with high carbon content results in a large amount of residual austenite after the direct quenching to ambient temperature. After cryogenic-tempering, the microstructure of surface layer is notably homogenized, and further transformation of retained austenite into martensite is promoted. The residual stress can be relaxed and the microstructure is stabilized after tempering at 240°C, along with an increase of the hardness of surface layer.
The research status and summary of adsorption and retention mechanism of polymer
Authors: Liu Yang , Wu Xingcai , Zhai Xuezhi , Shi Gang , Ye Yinzhu , Li Shichao , Xiao Peiwen
Published: August 2020

The polymer flooding technology has been established a relatively scientific and complete technical theory system, after decades of development. Theoretical and field applications have shown that the key to profile control and flooding is adsorption and retention of polymer in reservoirs. When the polymer flows through the porous medium of the reservoir, it will be adsorbed and trapped in the pores of the cores, resulting in serious decrease in the permeability of water in the porous medium of the reservoir, while only a slight decrease in the permeability of oil, increasing the mobility of crude oil, effectively increasing the injected water swept volume, and thereby improving the comprehensive economic benefit of water-flooding development reservoir. In order to further understand the adsorption and retention mechanism of polymer, guide the oilfield production, and achieve the purpose of low injection of polymer and the high production of oil, in this paper, we conducted a lot of research on the adsorption and retention mechanism of polymer at home and abroad. The comprehensive analysis shows that electrostatic and mechanical trapping are the main causes of adsorption and retention, followed by polymer concentration, degree of hydrolysis, rock wettability and formation mineralized water composition.
Preparation and photoelectrochemical properties of porous silicon/carbon dots composites
Authors: Kang Xiang , Wu Lin , Xu Jinhui , Liu Dong , Song Quangui , Hu Ya
Published: August 2020

Porous silicon/carbon dots composites were prepared by electrolyzing and deposition with two graphite rods working as electrodes. The porous silicon was prepared by metal assisted chemical etching of silicon powder and then added into the ultra-pure water electrolyte. The structure and morphology of porous silicon, carbon dots and porous silicon/carbon dots composites were characterized by SEM, XRD, UV-vis and PL et al. At the same time, we have tested the electrochemical performance of porous silicon / carbon dots composites electrode. The results show that the fluorescence property of the composites is better than porous silicon and carbon dots. After the deposition of carbon dots, the photoluminescence intensity of porous silicon increased around 1.4 times and the decrease of luminescence efficiency of the complex is only around 6.8%. And it shows excellent broadband light reflectivity from 200nm to 700nm, consistently below 20%.
Conductive WO3-x@CNT networks for efficient Li-S batteries
Authors: Yu Bo , Chen Yuanfu
Published: August 2020

Oxygen-vacancy-containing WO3-x nanodots homogeneously decorated on conductive CNT networks (WO3-x@CNT) have been synthesized by a simple and industrial spray-drying approach followed by annealing. Benefiting from the enhanced conductivity of CNT networks and the effective absorption for polysulfides by ultra-small polar WO3-x nanodots, the designed WO3-x@CNT/S cathode demonstrates excellent electrochemical performance, with an excellent rate capability (1000.1 and 518.2 mAh g −1 at 0.2 and 3 C, respectively), a high reversible specific capacity of 754.1 mAh g−1 at 1 C after 50 cycles.
Mechanical behavior of composite ship structures with open-hole
Authors: Li Xiaowen , Zhu Zhaoyi , Li Yan , Chen Qinglin , Zhang Xiaoying
Published: August 2020

Composite materials, as advanced structural and functional materials, are increasingly used in naval and civilian fields. There are different structures with open-hole in the ship hull. The open-hole damages the continuity of the composite structure and has a direct impact on the strength and stability of the composite structure. Therefore, it is of great significance to study the mechanical behavior of composite ship structures with open-hole to ensure the safety of the ship. Based on the numerical method, the mechanical behavior of the typical composite ship structures with open-hole was investigated, and the critical buckling load, buckling mode, post-buckling behavior, ultimate bearing capacity and stress concentration of the composite structures with open-hole were analyzed. The Hashin failure criterion and complete unloading failure model were used to analyze the nonlinear buckling behavior of different composite structures with open-hole. The results show that the ultimate bearing capacity of the composite structures with typical open-holes such as rectangle, rhombus, ellipse and circle is more than 2 times of its critical buckling load, this proves that the composite structures with open-hole can have a certain bearing capacity after initial buckling. Compared with the same scale structure without open-hole, the critical buckling load and ultimate bearing capacity are reduced by about 10% and 50%, respectively. The influence of various open-holes and layer thickness on the mechanical behavior of composite ship structures is estimated through the parametric study, which provides an effective reference for the design optimization and performance evaluation of composite ships.
Effect of non-metallic inclusions on fatigue life of high-speed railway bearings
Authors: Yang Ma Can , Zhang Gang , Wu Wang Yong , Qiang Zhang Zhen , Ming Ren Zhong
Published: August 2020

In the process of smelting and manufacturing of high-speed bearing steel, non-metallic inclusions are always inevitable, which destroy the continuity of the metal matrix and decrease the fatigue life of high-speed railway bearings seriously. Under the condition of obtaining the position and the number of the maximum contact load of the high-speed railway bearings, according to the Hertz contact theory, the maximum contact stress σmax between the roller and the raceway of the high-speed railway bearings and the half-width b of the contact surface is calculated, and then the stress distribution equation of the contact surface is obtained. According to the basic theory of fatigue life, the local stress-strain method was used to analyse the influence of the distance, depth and quantity between the inclusions contained in the raceway of the outer ring on the contact surface stress and the fatigue life of the high-speed railway bearings. Quantitative relationship between the influence of non-metallic inclusions and the contact fatigue life of high-speed railway bearings was determined, which provided scientific bases in the smelting process of high-speed railway bearing steel.