bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods for calculating the heat capacity of decafluorobutane in a liquid
Authors: Granchenko P P , Kuznetsov K I , Sukhikh A A , Skorodumov S V , Basidov R I 
Published: March 2021

Abstract
This work presents a comparison of the values of isochoric and isobaric heat capacities in a liquid in the range of parameters from 20°C to 140°C and pressures from 2 MPa to 10 MPa, obtained by two different methods. Under one of the proposed methods isobaric and isochoric heat capacities are obtained within joint thermal (pυT-dependence) and acoustic (speed of sound) measurements, the other method represents heat capacity values are obtained from a unified equation of state presented by the authors earlier based on the results of experimental and computational studies. New density measurements on 7 isotherms in the liquid and supercritical areas of state in the temperature range from 5°C to 141°C and pressure from 1.6 MPa to 10.9 MPa are presented. Estimation of the calculated based on experimental data for the isochoric heat capacity is ± 5%. The discrepancy between the calculated values of the heat capacity by both methods in the entire range of the studied temperatures reaches 30%, which is explained by the lack of experimental data on the heat capacity in the known literature.
Numerical modelling method of heat exchange in heat accumulators with many phases and free phase boundaries movement
Authors: Purdin M S 
Published: March 2021

Abstract
A correct implicit unconditionally stable numerical method for modelling heat transfer in heat accumulators with many phases and free phase boundaries movement of has been developed and presented. The stability of the implicit numerical scheme for approximating the energy equation is studied. As an example, a hardening process of zinc casting with a thickness of 10 cm was considered and compared with the results of calculations by another author.
The impact of anode gas diffusion layer structure on fuel cell performance
Authors: Fedotov A A , Tarasenko A B , Karanova D A 
Published: March 2021

Abstract
The gas diffusion layer (GDL) plays an important role in the operation of fuel cells with a proton exchange membrane (PEMFC). GDL is commonly used on three possible types of carbon fiber-con backing: carbon fabric, non-woven material, carbon paper. All three types have different properties, such as gas permeability, mechanical strength, electrical resistance, hydrophilicity and price. Paper is much cheaper than non-woven material, and replacing even one electrode could make a fuel cell cheaper. But replacement makes sense only if the same efficiency is maintained. In this work, two types of GDL as an anode in PEMFC were compared. As a result of the comparison, current-voltage and power characteristics were obtained.
The parameters of the off-grid power system with a biomass gasifier engine for the autonomous power supply of forest harvesters
Authors: Anisimov P N , Medyakov A A 
Published: March 2021

Abstract
The paper analyses the results of the simulation modelling of autonomous power supply system of forest electric drive harvesters. MATLAB with the use of dynamic modelling Simulink tools was employed for the simulation modelling. The modelled system incorporates gasifier for solid fuelwood, a heat engine, an electric generator, a battery, and electric drive engines for the mechanisms of a mobile wood chipper. The authors determined that the minimum 12 A h Battery is required to ensure the uninterrupted operation of an off-grid power system with a gasifier, a 300 kW heat engine and a 200 kW engine wood chipper. The model allows for measuring the system performance indicators in various operating modes. The specific consumption of fuelwood was 2.217 kg/kW h in the specified mode.
The Manufacturing Process of Recycled Polymer Composites reinforced with Natural Fibers – A Systematic Literature Review
Authors: Govinda  , Widiastuti Indah 
Published: March 2021

AbstractIn the light of growing global awareness in environmental sustainability, it is essential to employ more “environmentally friendly technology” which preserve natural resources. In the past decade, natural fiber composites with thermoplastic and thermoset polymers have been applied by several industrial sectors in various parts of the world. Natural fibers such as kenaf, hemp, sisal, abaca, and sugar palm have been widely used because they provide several advantages such as low cost, environmentally friendly, and reducing dependence on the use of materials that cannot be recycled. The use of recycled material for the development of natural fibre reinforced polymer (NFRP) has seeking current attention. This article reviewed several literatures on the manufacturing process of recycled polymer in NFRP material. The five-step systematic literature review (SLR) was chosen as the approach in reviewing the literature. The analysis of the selected articles revealed that a successful process for making recycled natural fiber reinforced polymers begun by appropriate treatment of natural fibers. Treatment of natural fibers using alkaline treatment (sodium hydroxide (NaOH) and silane treatment is the most influential factor in the success of the process of making recycled polymer composites reinforced with natural fibers. This study implies a new manufacturing trend for natural based fibre composites in recycled polymer matrix.
Effect of Adding of Pitch on the Darrieus Blade Against the Cut In Speed of the Savonius Type S - Darrieus Type H Hybrid Turbine
Authors: Ibadi Husni , Sangidzun Ahmad , Wijayanto Danar Susilo , Saputro Herman , Soenarto  , Triyono M Bruri 
Published: March 2021

Abstract
This research was aimed to analyze the effect of adding pitch angle to the performance of a Savonius Hybrid Type S-Darrieus Type H-Rotor wind turbine with variations in wind speed. This research used an experimental method with variations in pitch angle and wind speed. Variables taken in this study are wind speed, pitch angle addition, and wind turbine cutting speed. Variations in the addition of pitch angles are 0°, 5°, 10°, 15 °, 20°, 25°, 30°. The results showed that the addition of pitch angles to the blade influenced the cut in speed. The highest cut in speed is 4.2 m/s at the addition of pitch 0° while the lowest cut in speed is at 3.8 m/s at the addition of a 30° pitch angle.
Comparison Study of Solar Panels with Horizontal Turbine as an Alternative Electric Energy Source
Authors: Widyanto Dian Wahyu , Wijayanto Danar Susilo , Budiyanto Cucuk Wawan , Soenarto  , Triyono Mochammad Bruri 
Published: March 2021

Abstract
The effect of global warming has raised public awareness to seek energy sources that do not damage the environment and can be renewed, such as renewable energy. Renewable energy that is practically applied in people’s homes, namely sun and wind. This research studies about solar panels to determine the highest electrical power produced. Measurements are made by measuring the voltage and electric current generated by solar panels and measuring wind speed to determine the electrical power generated by wind turbines. This research was conducted in the Campus area of Universitas Sebelas Maret Surakarta. Solar panels produce the highest electric power of 26.42 Watts. This study states that solar panels produce electric power that is more effective and optimal than wind turbines. The power produced by the solar panels is 26.42 Watt, while the wind turbine produces electric power of 6.46 Watt.
The Role of Rice Husk Ash in Enhancing the Fresh Properties, Density, and Compressive Strength of Fly Ash Based Self Compacting Geopolymer Concrete
Authors: Ardiantoro D , Sunarsih E S , Sucipto T L A 
Published: March 2021

Abstract
This paper describes the effect of rice husk ash on the fresh properties, density, and compressive strength of fly ash-based self compacting geopolymer concrete (SCGC). Fresh properties were tested by the slump flow test. Density and compressive strength were tested with cylindrical concrete samples. Diameters of samples were about 150 mm and 300 mm high. The variations of Rice Husk Ash (RHA) as Fly Ash (FA) substitution were 0%, 5%, 10%, and 15%. The alkaline activators used Na2SiO3 and NaOH with ratio at 1.0 and a molarity value of NaOH was fixed at 14 M. The water-binder ratio was fixed at 0.3. The dosage of superplasticizer used 1%. The treatment of concrete used ambient temperature. The test results showed that rice husk ash decreased the slump flow; was not affected on the concrete density; and increased the compressive strength of SCGC. The maximum percentage of rice husk ash substitution to achieve the EFNARC slump flow standard was 7.16%. The density of the SCGC was 2076.4 kg / m3 – 2104.3 kg / m3, and classified to the normal concrete. The maximum compressive strength of SCGC was 11.476 MPa at the percentage of rice husk ash substitution about 8.65%.
Optimization of Refuse Derived Fuel (RDF) of solid waste in palm starch home industry through the variations of binder materials
Authors: Saputro H , Fadlullah V , Bugis H , Muslim R , Munir F A 
Published: March 2021

Abstract
A lot of energy consumption and the abundance of waste stimulate various alternative energy from biomass. One of the biomasses that has not been widely used is palm starch waste. Palm’s starch home industry in Indonesia produced solid waste that could be converted to synthesis gas through the gasification process. Production of palm starch increases in 2019, gives rise to accumulation waste, causes various diseases, and damages the environment, requiring specific handling. This study investigated the effect of binder material of RDF on palm starch waste. The variations of binder materials used tapioca, rice flour, and mangosteen peel. RDF of palm starch waste with variations of mangosteen peel binder produces the highest calorific value than starch and rice flour, 4009.62 cal/gr. However, RDF with tapioca flour binder has the highest volatile content, so that it can ignite and burn better than rice flour and mangosteen peel binder.
Investigating of the Relations among TPACK Components of Economic Teacher Candidates in Sebelas Maret University (UNS) in 2020: A Structural Equation Modeling
Authors: Santika Villa , Indriayu Mintasih , Sangka Khrena Bayu 
Published: March 2021

Abstract
This study examines the structural relationship between the components in TPACK. The sample of this study was 98 economics teacher candidates at Sebelas Maret University Surakarta, Indonesia. This research design is quantitative with structural equation modeling (SEM) analysis techniques. The results of this study indicate that the questionnaire is valid and reliable and the hypothesis shows that there is a significant influence between the TPACK components except TK, PK, and CK on TPACK. The results of the study can be used as reference material for future research using instruments that have been tested for validity and reliability in teachers who have taught during the pandemic to determine the TPACK of post-Covid-19 teachers who carry out online learning.
Measuring Critical Thinking Skills with the RED Model
Authors: Wulandari Riska , Baedhowi  , Hindrayani Aniek 
Published: March 2021

Abstract
Critical thinking skills are one of the core and fundamental skills that are needed in 21st-century learning. In education in Indonesia, critical thinking skills are contained in the 2013 Curriculum as one of the goals of education. This article provides insight into critical thinking skills and discusses the concept of the RED Model’s critical thinking skills and its indicators in measuring critical thinking skills. This research uses the Grounded Theory method, which aims to find new theories or to empower existing theories. The RED Model’s critical thinking skills framework has three main indicators including (1) Recognize Assumptions; (2) Evaluate Arguments; and (3) Draw Conclusions. The RED Model’s critical thinking skills framework and its indicators are expected to assist in encouraging the development of critical thinking skills and measuring critical thinking skills.
Effectiveness of ARCS Based Economic E-Book to Improve Learning Motivation and Learning Outcomes
Authors: Saputri Kartika Yunita , Santoso Sigit , Hindrayani Aniek 
Published: March 2021

Abstract
This study aims to test the effectiveness of ARCS-based economic e-book media to improve learning motivation and learner outcomes. This is back grounded by the lack of motivation of students’ learning in following the economic learning process so that the results of learning students in economic learning become not maximal. With good learning motivation, it will boil down to achieving good learning outcomes as well. The data collected in this study is motivational learning data collected through questionnaires and data on learning results collected through tests. Data analysis techniques are independent until t-test. The results of this study show that the test results for the average difference in learning motivation are significant (sig. = .000 < α = .05) and the study results are significant (sig. = .000 < α = .05). In the classes that received the treatment, the motivation of the students’ learning was high and the learning outcomes of the students were high. Thus, it can be concluded that ARCS-based economic e-book media is effective for improving learning motivation and learning outcomes of students.
Active Learning with SPSS Assisted Guided Discovery Learning Method to Improve Student’s Statistical Learning Achievement
Authors: Sulistyo L , Dwidayati N K 
Published: March 2021

Abstract
Guided discovery learning (GDL) is a learning method that uses a two-way system, namely the learning process involving students and lecturer who interact actively. The purpose of this study is to determine the effectiveness of learning statistics for students of Electrical Engineering at the Islamic University of Nahdlatul Ulama Jepara by using the SPPS-based GDL method. The sample consisted of 12 students taken from 87 students by means of random sampling. The type of research used is a mix method research, namely by comparing the means of the pre-test and post-test scores to determine the increase in student knowledge from a quantitative point of view then answer sheet analysis and interviews are conducted to determine effectiveness from a qualitative point of view. Qualitative data were taken from data from two subjects who were selected by means of purpose sampling. Quantitatively and qualitatively, the results of this study indicate that the GDL method is effective in improving student achievement in statistics courses.
Visual, Symbolic, and Verbal Mathematics Representation Abilities in Junior High School’s Students
Authors: Novitasari P , Usodo B , Fitriana L 
Published: March 2021

Abstract
The purpose of this research is to describe the ability of mathematical representation that includes visual, symbolic, and verbal representations of eight grade of junior high school students in solving math problems. This research is a qualitative descriptive study. The instrument that is used in this research is the main instrument (researcher) and supporting instruments (test and interviews). The test is given to 31 students of eight grade B of Junior High School 2 Ngawi. The research subject consisted of two students who provided more information to be studied more deeply. Subjects were selected based on the purpose of sampling technique, namely based on the results of students’ written answers which showed more than one representation ability for each number. The results showed that students were able to use various kinds of representations in solving the problems given, although there were still errors in the calculations. Students can fulfill their visual representation skills well, namely presenting information in the image form. Students are less able to find the ability of symbolic representation, which is marked by formula errors and calculation errors. Students can fulfill verbal representation well, namely writing statements in written sentences.
Students’ Mathematical External Connection Ability Based on Personality Types of Sensing Intuition
Authors: Kusumastuti A N , Budiyono  , Indriati D 
Published: March 2021

AbstractMathematical external connection ability is the ability to relate topics in mathematics to the other learning subject and daily problems. Sensing and intuition personality is a characteristic of students receive and process information. For this reason, personality types can influence mathematics learning and mathematical external connection ability. The main purpose of this research is analysis of students’ external connection skill that has sensing or intuition personality. This study method used was descriptive the qualitative method with four students of class VII in Junior High School. Subject selected using purposive sampling, each subject represents one personality and one indicator. The data from this research were obtained from questionnaires, mathematical connection external test, and interviews. The results obtained that intuition student can applying the concepts and mathematical procedure to other subjects, but sensing student difficulties. Both of sensing and intuiting can use mathematical relationship in everyday life problems.
A Case Study on Mathematics Instructional Implementation: Teacher’s Perspective on How Mathematics Teachers Face The Pandemic Covid-19 Situation
Authors: Millatasyifa M L , Nurhasanah F 
Published: March 2021

Abstract
Learning activities carried out by teachers are at the core of the learning process. How the implementation of learning activities have a major influence on students’ understanding, especially when facing a Covid-19 pandemic situation. This paper aims to explain how mathematics learning takes place during the Covid-19 pandemic based on the teacher’s perspective. The research was conducted at MTs Sambirejo Sragen. The selection of research subjects was made based on purposive sampling. The research subjects were chosen by all mathematics teachers at MTs Sambirejo. The data in this study is a description of the teacher’s perspective regarding mathematics learning activities during the Covid-19 pandemic. The data collection techniques are interviews, documentation and observation. As a result, in general there were two types of learning activities on mathematics online learning during the Covid-19 pandemic situation at MTs Sambirejo. However, the two types of learning activities still use a teacher-centered learning approach. Even though the current pandemic condition is very different from the conditions before the pandemic. Explicitly, the actual process of learning activities in online learning has a consequence that all learning activities can be carried out in a more mobile and dynamic manner.
The Analysis of Students’ Metacognition in Solving Math Problems Based on Self-Efficacy
Authors: Fadillah R , Budiyono  , Nurhasanah F 
Published: March 2021

AbstractMetacognition holds a particular part in the learning process, especially in mathematics because solving math problems is not enough just by using numeracy skills, but metacognitive knowledge is also essential. The aim of this research is to analyze the metacognition of students’ junior high school in solved math problems based on students’ self-efficacy. Data collection techniques used in this study were questionnaires, tests, and semi-structured interviews. The main instrument in this study is the researcher and additional instruments were self-efficacy questionnaires, geometry tests and interview guides. This is a qualitative study with a case study design. The participants of the study were 20 students of grade 8th. Two out of twenty become the subjects of the study who selected using purposive sampling technique. The study showed that students with high self-efficacy in solving math problems can fulfil all indicators of each metacognition component, consisting of knowledge about cognition and regulation of knowledge.
Integration of Local Traditions Bugis-Makassarese: Learning Strategies to Improve Mathematical Communication Skills
Authors: Asfar A M I T , Asfar A M I A , Nurannisa A 
Published: March 2021

AbstractCommunication skill is of local Bugis-Makasar one of skill needed in mathematical learning in order that the students can solve the problem in social life particularly economic mathematic. Integration of local traditionsipakatau, sipakaingeandsipakalebbiconsists of philosophy which can increase students’ communication skill. The purpose of this study is to find out the improvement of students’ communication skill of STKIP Muhammadiyah Bone in using learning strategy of 3S. Design of this study was experimental research Quasi Experimental Design using Nonequivalent Control Group Design. Based on the results of this study can be concluded that the earning strategy of 3S is effective in improving student’s communication skill in economic mathematics in STKIP Muhammadiyah Bone not only on students’ cognitive side but also affective and psychomotor side.
Problems and prospects of distance learning in teaching fundamental subjects to future Mathematics teachers
Authors: Bobyliev D Y , Vihrova E V 
Published: March 2021

AbstractThe research analyzes experience of implementing the coursesMathematical AnalysisandHistory of Mathematicsfor future Mathematics teachers in the system of managing electronic academic courses (SMEAC) at Kryvyi Rih State Pedagogical University (KSPU). To create the courses, there is a block-modular approach enabling not only structuring the process of studying fundamental mathematical subjects in the distance form of training, but also controlling the rate and depth of students’ mastering the material. There are examples of laboratory works onMathematical Analysisperformed by students independently in the computer mathematics system CoCalc.
The origin of misconceptions in inorganic chemistry and their correction by computer modelling
Authors: Derkach T M 
Published: March 2021

Abstract
The paper goal was to analyse the typical mistakes in the learning of the university course of inorganic chemistry, determine the origin of misconceptions and estimate the effectiveness of the use of computer simulations to correct false chemical concepts. Ten problems that are the most typical for students were revealed. One of the leading causes of their occurrence is the failure of many students to form mental relationships between different levels of representation of chemical knowledge - microscopic, macroscopic and symbolic. Other reasons include an insufficient understanding of the material, the incompleteness of the knowledge of the microscopic basis of processes, and inability to work with different models, including misunderstanding of their purpose and constraints. NetLogo programming environment was used for students’ self-administering tests to study gas laws. Scope for the usage of NetLogo models was estimated in correcting of incorrectly formed conceptions of the chemical knowledge. Independent work with NetLogo models facilitates the formation of stable relationships between multiple levels of representation of chemical information. It improves an understanding of the studied topic fundamentally, and this holds for all students practically independently of their grounding level in chemistry. The introduction of computer simulation into the practice of teaching chemical subjects shows promise. Still, it requires the solution of several scientific, methodological, logistical and organisational issues.