bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variations of the problem-solving strategies in plane geometry of junior high school students
Authors: Pratikno H , Sugiman  
Published: November 2019

Abstract
The purpose of this study was to explore the problem-solving strategies of junior high school students on plane geometry topics. Using a qualitative approach, as many as 40 students were given tests and one student was interviewed on each of the different problem-solving strategies. After checking the results of student answers, it turned out there were three strategies used by students. The first strategy was that students are able to answer questions by guessing the answer directly then testing them. The second strategy was that students use ratio in finding answers. The third strategy was that students used analogy strategies with variables. The results showed that 13 students used the first strategy, 20 students used the second strategy, one student used the third strategy, and six students did not use the strategy or did not answer. The most used problem-solving strategy by students is the ratio strategy, with the percentage of students using the strategy is 50% of the total students who participated in this study.
Utilizing mobile phones in mathematics class: teachers’ and preservice teachers’ perceptions
Authors: Nofriyanti Devi , Setyaningrum Wahyu 
Published: November 2019

Abstract
Mobile phones are one of the technologies that can be used to support mathematics learning, but currently the use of it in the classroom seems to be rarely used by teachers in Indonesia. This study examined a total of 44 mathematics teachers and 62 mathematics preservice teachers’ perception in Indonesia for the use of mobile phones in the classroom. Participants were given a questionnaire to determine their support for mobile phones use. The results showed that majority of the participants supported the use of mobile phones for learning. They agreed that mobile phones are useful to provide learning opportunities anywhere and anytime, increase access to technology in the classroom, and provide opportunities for differentiation in instruction. As for barriers, participants worry about students’ access application that is not in accordance with the teacher’s instructions. They perceived that instructions, control of students and time allocation are the things that teacher need to pay attention before using this media. Although majority teachers reported their support for the use of mobile phone in the classroom, the implementation of this media needs to be improved.
Improving trigonometry learning motivation using Geogebra-Assisted Guided Discovery Student Worksheet (GDSW)
Authors: Hernawati Kuswari , Surjono Herman Dwi 
Published: November 2019

Abstract
This study aims to determine student motivation using Geogebra assisted GDSW. The instrument of this research are worksheet compiled with guided discovery approach and student motivation questionnaire. The motivation questionnaire consists of three aspects of interest, pleasure, and satisfaction, which are outlined in 15 questions submitted to 118 of 10th grade students. Data analysis of the questionnaire using Likert scale 1-4, with ideal score is 4, and the lowest score is 1. There are five interval classes. The result of this research, that student motivation using Geogebra assisted GDSW has an average of 3.11 with the category of "good". It means that students have good motivation on learning using Geogebra-assisted GDSW.
A survey on the perception of students against technology in learning mathematics
Authors: Fitriasari L , Abadi A M 
Published: November 2019

Abstract
Discoveries related to information and communication technologies change the viewpoints of humans against the world including the world of education. The role of technology supports many activities, especially learning activities, and it also can support the learning process. Education systems in the globalization era show the transformation which is previously manual and conventional into the system that effectively and efficiently can improve the information technology. Thus, this research aims to identify the perception of students toward technology in learning especially mathematics. This study uses a survey approach, with data collection methods namely questionnaires distributed to 42 students. The results show that 70% of students had enthusiasm and interest in technology especially mathematics learning.
Self-regulated learning in blended learning approach
Authors: Setyaningrum W 
Published: November 2019

Abstract
Blended learning allowed students to manage their own pace of learning especially in the online session. This might foster students’ self-regulated learning. This claim, however, need to be investigated with more empirical data. This study, therefore, intended to examine the effect of blended learning on students’ self-regulated learning. A quasi-experiment with the pretest and posttest group design was employed in this study. A total of 115 grade 10 students was cluster randomly selected among senior high schools in the city of Yogyakarta. Two different classes of samples were set, namely experiment class using blended learning android-based-game, and control class using offline class. The students in the two classes learn the same material that is about Function and its graph. Data of students’ self-regulated learning was collected through a questionnaire with five Likert scale. The data was analyzed using Analysis of Variance (ANOVA) technique and it was found that: there is a significant difference of self-regulated learning between students who learn in blended class and those in offline class. This study offers insights on the use of blended learning to foster the students’ self-regulated learning especially in learning mathematics. Nevertheless, the design of blended learning need to considered particularly when and what kind of learning material should be delivered online and offline.
Learning mathematics from erroneous example in individual and collaborative setting: is it effective to facilitate students’ mathematical disposition?
Authors: Rafi I , Setyaningrum W 
Published: November 2019

Abstract
Learning mathematics from an erroneous example—worked example contains error—in individual and collaborative setting could be potential to facilitate students’ mathematical disposition through activities such as find, explain, and correct the errors as well as solve a problem similar to the erroneous example. This study was intended to examine the effectiveness of learning mathematics from the erroneous example in individual and collaborative setting with regards to students’ mathematical disposition. This quasi-experimental research with non-equivalent group pre-test and post-test design employed a 30 items-questionnaire to gather data of mathematical disposition. The participants were 45 students of grade 11th in the one of public senior high school in Yogyakarta. The collected data of students’ mathematical disposition then were examined by using paired samples t-test, one sample t-test, and one-proportion z-test. This study revealed that learning mathematics from erroneous example could not significantly facilitate students’ mathematical disposition in both individual and collaborative setting. The possible reasons behind these findings are discussed.
Is there any interaction effects of students’ gender and mathematical disposition towards learning achievement?
Authors: Andari I E , Sugiman  
Published: November 2019

Abstract
Mathematics learning achievement is affected by external and internal factors. External factors include the environment and teachers, while one of the internal factors is the student’s gender. However, the research findings of gender difference effects on learning achievement showed varied results. It indicates that there might be other factors which have important effects on gender differences towards learning achievement, such as mathematical disposition. The aim of this quantitative study is to describe the interaction effects between students’ gender and mathematical disposition towards learning achievement. Participants consisted of 200 high school students. Data were obtained using a questionnaire on a Likert scale and the score of the daily test result. Furthermore, the data were analysed using Two-way ANOVA. Findings revealed that there is no interaction effect between the two variables towards learning achievement. As an individually separated factor, mathematical disposition does have an effect on students’ learning achievement, but, is not the case with students’ gender. Results and recommendations are further discussed in this paper.
Students’ perception of tutoring judging from students’ academic ability
Authors: Nugroho I A , Jailani  
Published: November 2019

Abstract
This study aims to find out the perception of students with high academic abilities and students with academic skills that are not high on the implementation of tutoring by tutoring institutions in schools. This type of research is qualitative research with descriptive analysis. The sample in the study were students of Junior High School. Data collection instruments use interview and documentation guidelines. The results of this study are 1) Students’ perceptions based on the expectations of the learning guide regarding academic ability have been fulfilled, there is no significant difference in perception concerning students’ academic abilities. Learning precision tends to increase. 2) Students’ perceptions are reviewed based on the need for tutoring regarding students’ academic abilities, in general, have also been fulfilled, meaning students with various academic skills feel they need tutoring to be able to support the learning process.
Analysis of student difficulties on algebra problem solving in junior high school
Authors: Sugiarti L , Retnawati H 
Published: November 2019

Abstract
Algebra is one of the mathematical sciences studied in junior high school. Some students may have difficulty learning algebra. This study aims to determine the difficulties experienced by students in solving the problem of algebraic operations. The type of this research is qualitative research with case study approach. Subjects in this study are students of grade 8D 1 Salam Magelang junior high scchool, Central Java in the semester of the year 2016/2017 academic year. Methods of data collection used include algebraic operations tests, open questionnaires, and documentation. Data analysis techniques through data reduction, data presentation, and conclusions. The result of the research that there are students’ difficulties in doing algebraic problems related to concept and principle. Students difficulties experienced related to the concept of difficulty in determining variables and constants including but not understanding the definitions of variables and constants, and difficulties in applying the concept of division in algebra. The difficulty experienced in terms of principle is the application of the principle of addition to the algebraic form, the reduction in algebraic form, multiplication on the algebraic form, simplifying algebraic fractions, factoring, and solving algebra-related stories.
Profile of students’ mathematics anxiety
Authors: Azizah L N , Mahmudi A , Retnawati H 
Published: November 2019

Abstract
Mathematics anxiety has gained massive attention from researchers and mathematics teachers. It happens among students and even becomes a determinant of their view towards mathematics in the future. This study purposes to observe the profile of students’ mathematics anxiety in one of public junior high school in Sleman, Yogyakarta, Indonesia. The type of this research is descriptive quantitative research. This study engaged a purposive sampling technique, and the instrument used is a sheet of mathematics anxiety questionnaire with Likert scale. The analysis conducted is descriptive. The result of the analysis indicates that students’ mathematics anxiety profile tends to belong in the medium category. Based on the results of research and discussion, it can be concluded that the students’ mathematics anxiety in one of public junior high school in Sleman needs to be well-managed.
Analysis of junior high school national examination year 2014 to 2017 on facilitating students’ high order thinking skill
Authors: Rozien M I , Retnawati H 
Published: November 2019

Abstract
One of the thinking skills of students who are being talked about by various groups in the general public and education is higher order thinking skills (HOTS). In Bloom’s taxonomy, HOTS is a student’s ability to answer questions with a level of analyzing, evaluating, and creating. One form of test that is presented by the implementation standard of assessment in Indonesia is the National Examination. Regarding this matter, the analysis of HOTS content on the national examination tool is an urgent matter to do. This study aims to determine the contents of HOTS in the National Examination of Junior High School Mathematics subjects in 2014 to 2017. This research is a descriptive study with a qualitative approach. Data was collected with non-tests given to several experts. Sources of data obtained by researchers came from their own researchers, 2 mathematics teachers, and 3 mathematics lecturers. In the validity of the data and decision making, it is obtained from the quantity of opinions from the six experts. The results showed that the HOTS items from 2014 to 2017 were different. The number of HOTS items in the National Examination from 2014 to 2017 were 12, 16, 18 and 10. However, from the HOTS items in 2014 to 2017 there were no questions about type C6, namely creating.
The effect of changes in mathematics curriculum in improving students’ reasoning skills and mathematical problem solving
Authors: Yaman N A P , Jailani  
Published: November 2019

AbstractThis study aims to describe the effect of changes in mathematics curriculum on mathematical reasoning skills and problem solving for junior high school students in Bima, Indonesia. Curriculum changes in Indonesia are motivated by several factors, including because students still have not been able to maximize the power of reasoning and problem solving so that the previous applied mathematics curriculum is deemed necessary to be refined so that the power of reasoning and solving mathematical problems can be maximized by students. The data in this study were obtained through giving a test to the eighth grade junior high school students in Bima. The evidence of validity of instruments was obtained from an expert judgment in the form of agreement on the feasibility of the each item of instruments. The estimation of reliability of instruments using the Kuder-Richadson formula (KR-20) with the reliability coefficient for reasoning and problem solving instruments are respectively 0.72 and 0.73. The results showed that there were no significant differences in mean scores of mathematical reasoning and problem solving between students of The Previous Mathematics Curriculum group and students of The New Mathematics Curriculum group indicated by the F 0.02 value with a significance value of (p) 0.162 in the two test group MANOVA or there is no effect of changes in mathematics curriculum on students’ reasoning abilities and mathematical problem solving. This study also found that students from both groups obtained the lowest average score on reasoning indicators drawing conclusions, while the lowest average score of the two groups of students in solving mathematical problems was on the aspect of understanding problem information.
Numerical characterisation of the performance of flow rate on a non-contact vortex gripper
Authors: Anand Chandran C S , Sajikumar K S , Jayaraj K 
Published: November 2019

Abstract
On manufacturing industries like semiconductor wafers, Manufacturing of medicine or Food processing industries require repeated handling of clean products such as wafers, Food products, etc. which are needs to be frequently handled and transported. This handling can be further ameliorated by Vortex Grippers. Vortex levitation can achieve Non-Contact handling by blowing air through a tangential nozzle into a vortex cup, thus swirling air flow forms which generates negative pressure. The suction force generated by the vortex is more than enough to keep the workpiece without contact. In the present study, a non-contact handling device called vortex gripper is modified by changing some design parameters. However, when a conical shaped vortex cup is used, a 60% increase in gripper lifting force is achieved with the same air consumption as reported early.
Fluid structure interaction simulations and experimental validation of a pipeline immersed in liquid
Authors: Kumaresan D , Lekshmi A , Srinivas Kodati , Thomas Suresh Mathew , Sruthy S 
Published: November 2019

Abstract
In launch vehicles, there are number of fluid systems to cater to various requirements like propellant filling, draining to/from tanks, venting of ullage gases, pressurization of the tanks, feed systems to convey propellants to engine from tanks, lines to convey command gas to actuate various valves etc. These pipe lines are subjected to environmental loads i.e. vibration loads when the launch vehicle starts its course to place the satellite into its designated orbit. It is essential to study the dynamic characteristics of these pipe lines for the design of them for vibration loads. The response of these pipelines depends on fluid environment in which they are immersed. If a pipe line is immersed in liquid, its dynamic characteristics vary largely from that of a pipeline vibrating in ambient environment (air). If the pipe line immersed in fluid, natural frequency reduces and damping increases due to the added mass and fluid viscosity respectively. In order to study these effects, FSI studies are carried out on a pipe line immersed in water using ANSYS CFD and Mechanical software. Convergence studies with respect to time scale are carried out to benchmark the simulation procedure. This simulation procedure is validated by conducting the experiments.
Numerical Analysis of Combustion and Film Cooling in LOx-Methane Rocket Engine
Authors: Arun M , Amith Raj R , Jose Prakash M 
Published: November 2019

Abstract
Nowadays methane is considered as an alternative fuel for rocket engine application. It is abundant in the outer solar system that can be harvested from mars, Titan, Jupiter, many other planets and moon. The properties of cryogenic methane like higher density, higher vaporization temperature, less challenge in storage requirement compared to cryogenic hydrogen and its higher specific impulse, superior cooling capability and higher coking limit compared to kerosene created a renewed interest on space scientist in choosing methane as a propellant. Combustion and film cooling involving supercritical and transcritical regimes in a high pressure rocket engine combustion chamber is a challenging problem for the rocket engine designers. At supercritical and transcritical conditions, the thermophysical and transport properties exhibit tremendous variations which makes modeling combustion and cooling a demanding task. The present study is based on the oxygen methane thrust chamber model B at DLR P6.1 test bench. The finite volume based software ANSYS Fluent 15.0 is used for the numerical studies. The combustion is simulated using single step eddy dissipation approach. The real gas effects are incorporated using Soave Redlich Kwong cubic equation of state. The numerical scheme is validated by comparing the results obtained with the experimental results reported in literature. Investigations have been carried out to study the effect of film cooling on chamber wall temperature and wall heat flux for different oxidizer inlet temperature. The result revel that the hot gas temperature near the wall is higher in the transcritical combustion compared to supercritical combustion.
Enhancement of the thermal performance of a loop heat pipe using silica-water nanofluid
Authors: Jose Jobin , Baby Rajesh 
Published: November 2019

Abstract
Loop heat pipes (LHPs) are heat transfer devices which are capable of transferring large amount of heat energy over long distances. This paper presents the results of numerical investigations carried out to determine the effect of silica-water nanofluid on the thermal performance of a LHP. Silica-water nanofluid at 2 % nanoparticle concentration and deionised water are considered as working fluids. The power input is varied from 40 to 320 W in steps of 40 W. The numerical results are validated with experimental data available in the literature. LHP using deionsed water is used as the baseline case. The results shows that silica-water nanofluid can significantly enhance the thermal performance of the LHP when compared with the baseline case. The evaporator temperature of LHP using nanofluid reduced by 27 % than the baseline case. The LHP attained steady state faster (150 s earlier) with the presence of silica nanoparticles due to enhanced thermal properties. Thus silica-water nanofluid based loop heat pipes proves its potential as a suitable working fluid for a wide range of applications.
Thermodynamic modelling of hybrid adsorption system
Authors: Abhishek P , Baiju V 
Published: November 2019

Abstract
The ability of adsorption based desalination system to cogenerate distilled fresh water and cooling effect provides an increasing attention in the field of cooling and desalination technologies. Eco-friendly adsorption cycles are capable of producing the hybrid effects (desalination& cooling) with low temperature heat source having temperature range from 50°C to 90°C. Adsorption characteristics (isotherm) of silica gel-water and zeolite-water have been presented in this study. Dubinin-Astakov (D-A) and Dubinin-Radushkevich (D-R) adsorption equilibrium equations are used for comparing the performance of silica gel and zeolite. Results show that maximum water production rate in the case of silica gel adsorbent is stabilised at lower regeneration temperature, ranges from 80°C to 120°C, where as in zeolite it is in the higher range from 150°C to 250°C. Maximum COP of the system obtained is 0.65 for silica gel-water at a regeneration temperature of 80°C where as 0.35 for zeolite-water at 110°C. Study concluded that the performance of the system using silica gel-water adsorbent is comparatively better than zeolite-water pair.