bluuebunny/crossref_metadata_2025_split huggingface dataset:
Manufacturing of Natural Fiber-Reinforced Recycled Polymer–a Systematic Literature Review
Authors: Kusuma Sandy Sidik Wisnu , Saputra Holam Cahya , Widiastuti Indah 
Published: March 2021

AbstractIt is necessary to analyze the manufacturing process of recycled natural fiber reinforced polymers to produce polymer composites that are successful in the manufacturing process. This discussion begins with the manufacturing process of natural fiber reinforced recycled polymers. The outline of this article refers to the manufacturing process, manufacturing process constraints, and the appropriate methods of the manufacturing process. The literature review describes the manufacturing process of natural fiber reinforced recycled polymers with the constraints encountered during the manufacturing process by investigating suitable methods of treating natural fibers for success in the manufacturing process of natural fiber reinforced recycled polymers. The five-step systematic literature review (SLR) was chosen as the approach in reviewing the literature. The analysis of selected articles reveals that the successful manufacturing process of natural fiber reinforced recycled polymers is the treatment of natural fibers, followed by a manufacturing process that matches the polymer manufacturing needs. Treatment of natural fibers using alkaline treatments (sodium hydroxide (NaOH) and stearic acid ((CH3(CH2)16COOH)) is the most influential factor in the success of the manufacturing process of recycled natural fiber reinforced polymer composites.
Experiential Learning Using Solar Tracker Prototype In Industrial Automation Course
Authors: Juliyanto Nur Arif Suko , Widiastuti Indah , Akhyar Muhammad 
Published: March 2021

Abstract
Experiential Learnings is based on the understanding that the knowledge created as the result of an experience. Experiential Learning consisted of four stages, abstract conceptualization, active experimentation, concrete experience, and reflective observation. Experiential learning - Based learning is considered to have characteristics that are expected in the 21st Century Skills Learning. This study aims to develop experiential learning-based instructional design in Production Automation courses using a solar tracker system prototype. The effectiveness of the learning design is measured from the student learning outcomes and responses of the questionnaire provided. The control system subject in the production automation course is considered to have abstract and complex learning material so that it requires visualization to facilitate understanding. The development of the instructional designs is carried out using the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) model. The instructional design of the course was implemented in a class consisting of 40 students in the department of Mechanical Engineering Education in a state university in Central Java, Indonesia. From a series of lectures during the course of Production Automation, the instructional design developed based on experiential learning approach received a positive response from the students. The student learning outcomes were also considered good with the average scores of more than 80. This study shows that experiential learning approach could stimulated student learning in mechanical engineering subject.
Mechanical Properties of Bamboo on Virgin and Recycled High-Density Polyethylene Matrix
Authors: Santosa Dicky Permana Adji , Widiastuti Indah , Suharno  
Published: March 2021

Abstract
Natural fiber-reinforced polymer composites are considered to have advantages over synthetic fibers, namely that they are more environmentally friendly but with better mechanical properties. The purpose of this study was to make a pure / recycled HDPE (High-Density Polyethylene) composite with bamboo fiber reinforcement by analyzing the mechanical properties of the composite. The method used in this research is experimental with a quantitative approach. Experiments are carried out by creating or manipulating certain conditions and by providing control over the test specimen. Pure / recycled HDPE plastics and bamboo fibers will be mixed in a machine extrusion molding with a temperature heater (160, 165, 170, 175) ° C. Before fabrication, bamboo fibers are treated with alkaline treatment, namely by immersing 5% NaOH. The ratio of mass fraction between vHDPE/rHDPE and bamboo fiber was 70%: 30%. This study evaluated the mechanical properties of HDPE-bamboo composites using Izod Impact testing with ASTM D 256-05 standards. Tests were carried out to analyze the differences between pure HDPE and recycled HDPE matrices on bamboo fiber reinforced composites. The mechanical test results showed that the impact strength on bamboo composites with recycled HDPE matrix was 2.69 (KJ / m2) while bamboo composites with pure HDPE matrices had an impact strength of 1.6 (KJ / m2). Thus, the mechanical properties measured by impact strength on composites with recycled HDPE matrices were better than composites with pure HDPE matrices. In accordance with the results of research that has been done, recycled HDPE can be used as a matrix composite with mechanical properties that are not too different from composites with pure HDPE matrices. This can be done as a means of utilizing recycled HDPE waste instead of pure HDPE.
Characteristics of recycled HDPE/bamboo fibre composite
Authors: Rohmat  , Widiastuti I , Wijayanto D S 
Published: March 2021

Abstract
Increasing the mechanical properties of recycling can be done by adding natural fibers into composite materials. The focus of this research is to develop a composite using bamboo as a reinforcing material and recycled High Density Polyethylene (HDPE) as a matrix using the extrusion method. This study aims to analyze the mechanical analysis between bamboo fiber-based composites using a pure HDPE matrix and composites using recycled HDPE matrices at a matrix volume fraction: 70%: 30% fiber. Mechanical tests were performed using the tensile testing machine model RAY-RAN Test Equipment M500-50CT with ASTM D 638 standards to evaluate the tensile strength and modulus of the composite. The results showed that the tensile strength and Young’s modulus of bamboo fiber reinforced rHDPE composites were 8.764 MPa and 52.0152 MPa, respectively. While the bamboo composite with a vHDPE matrix has a tensile strength of 9.3312 MPa and a Young Modulus value of 94.8468 MPa. Thus, bamboo fiber reinforced composites with pure HDPE matrix have better mechanical properties than bamboo composites with recycled HDPE matrices. Differences in matrix shape can affect composites resulting from such fibers.
The Use of Rice Husk Ash in Enhancing the Material Properties of Fly Ash-Based Self Compacted Geopolymer Concrete
Authors: Sari A N , Srisunarsih E , Sucipto T L A 
Published: March 2021

Abstract
Concrete is a material that is needed for building construction or others is increasing. Construction increased as cement use increased. The continued use of cement will cause environmental damage, cement is the 8th largest source of carbon gas emissions in the world. One of the revolutionary developments using environmentally friendly materials as a substitute for cement is geopolymer concrete. Alternative materials rich in silica and alumina for the manufacture of geopolymer concrete, namely adding rice husk ash (RHA), fly ash, silica fume, glass powder, as substitute for cement. A cement substitute can use RHA as partial substitute for geopolymer concrete based on fly ash, which is rich in silica and alumina. For the binder, an activator is needed, the activator itself usually uses NaOH and Na2SiO3. The purpose of this study was to determine the effect of rice husk ash as a partial substitution of fly ash on split tensile strength and porosity of geopolymer concrete and determine the optimum percentage of use of RHA to produce tensile strength and porosity in geopolymer concrete with material calculations using EFNARC 2005. Geopolymer concrete which binders using 14M NaOH and Na2SiO3, and binders namely Fly ash and rice husk ash, with variations for RHA 0%, 5%, 10%, 15%. Sample in the form of cylinder with diameter of 150 mm and height of 300 mm for tensile strength and cylinder with diameter of 2 inches and height of 5 mm for porosity. The specimens were treated for 28 days with room temperature curing. From the data obtained, it can be concluded that there is an effect of RHA to increase tensile strength and reduce porosity in geopolymer concrete with an optimum variation of 10%, with an optimum tensile strength of 1.061 MPa, and minimum porosity of 13.13%.
Natural Fiber Reinforced Polymer in Automotive Application: A Systematic Literature Review
Authors: Huda Mohammad Khoirul , Widiastuti Indah 
Published: March 2021

Abstract
Efforts to develop effective and innovative materials are increasingly being developed by researchers, especially in the development and utilization of NFRP (Natural Fiber Reinforced Polymer) in the automotive sector due to increased demand and increased ecological awareness. The purpose of this literature review article is to provide up-to-date information on the application of NFRP and plastic recycling in the automotive sector as well as consideration of selecting natural fibers for use as reinforcing composites in the automotive sector. This literature review focuses on the progress of the development of polymeric materials applied in the automotive field. Referring to defined inclusion and exclusion criteria, 30 articles in polymer composite studies published between 2015 and 2020 were selected for further investigation. The analysis of selected studies revealed that several leading car manufacturers have produced and developed products from NFRP or recycled plastics with natural fiber reinforcement because they are relatively cheap, lightweight, and able to reduce exhaust emissions. The great potential of using NFRP materials and recycled plastics in the automotive sector presents a future challenge, namely the increasing need for natural fiber in the long term which will certainly have an impact on ecosystems and biodiversity.
A preliminary study of moving droplet combustion of biodiesel (B20) in a microgravity environment
Authors: Saputro H , Rahmadi W , Wijayanto D S , Muslim R , Fitriana L , Munir F A 
Published: March 2021

Abstract
The characteristics of B20 biodiesel droplet combustion on flame propagation rate at microgravity conditions are fascinating to study. The observation of Biodiesel B20 fuel was chosen because it supports the Indonesian government policy on the use of alternative energy. This research is an initial stage to determine the effect of variations in the speed of motion of biodiesel B20 droplets on the flame propagation distance. At this initial stage, the droplet velocity is set at 5 mm / s. There are three droplets used, namely droplet A (igniter droplet), droplet B (flame source droplet), and droplet C (observation droplet). Each droplet has a diameter of 1 mm. Data was collected directly through video analysis to determine the propagation distance of SBC/d0. The results showed that the investigative droplet (C), which was 3 mm from droplet B, had a maximum burnt distance of SBC/d0 = 4 - 4.2.
Cluster Analysis for Student Grouping Based on Index of Learning Styles
Authors: Pamungkas Allan Auri Putra , Maryono Dwi , Budiyanto Cucuk Wawan 
Published: March 2021

AbstractThis research aims to group students of Information and Computer Education, Universitas Sebelas Maret into classes based on the similarity of student’s learning style, and to analyze the characteristics of each group. In this research we used Felder and Silverman learning style model (FSLSM) that includes four dimensions, which are (1) learning process; (2) learning perception; (3) information input; and (4) information understanding. We used a quantitative descriptive method combined with cluster analysis technique. The subject of this research were 58 2ndyear students of the Department of Computer and Informatics Education Universitas Sebelas Maret. Assessment of learning style characteristics was done by using the Index of Learning Styles (ILS) instrument developed by Felder and Soloman. We applied a hierarchical clustering method to the student’s ILS data for the cluster analysis. This research indicated that two dominant clusters were formed with different characteristics in the dimensions of learning styles. Cluster 1 has a reflective preference in the dimension of learning process with an average of -3.76; a sensing preference in the dimension of learning perception with an average of 4.24; a visual preference in the dimension of information input with an average of 5.21; and a global preference in the dimensions of information understanding with an average of -2.66. Whereas cluster 2 has an active preference in the dimension of learning process with an average of 2.52; a sensing preference in the dimension of learning perception with an average of 1.48; a visual preference in the dimension of information input with an average of 5.08, and a global tendency in the dimensions of understanding information with an average of -0.04. We either found some outliers with different characteristics of learning style outside the two clusters. The results of this research can be used by lecturers to determine the appropriate learning strategy for each class.
How Students’s Higher Order Thinking Skills Through E-Learning During the Covid-19 Pandemic? What does it have to do with University?
Authors: Setyowati Ririn , Sarwanto  , Muzzazinah  
Published: March 2021

Abstract
This study describes the higher-order thinking skills of students at the elementary school level using e-learning during the Covid-19 pandemic. The research subjects were 183 students at the elementary school level in Ngawi Regency, East Java. The data collection technique uses the HOTS development test which includes seven subjects, namely natural sciences (IPA), Pancasila and civic education (PPKn), Indonesia language, mathematics, social sciences (IPS), cultural arts and crafts (SBdP), and physical education, exercise, and health (PJOK). The results showed that students obtained the highest score of 96,7 and the lowest of 30,0. The percentage of subjects with the greatest difficulty through the use of e-learning was physical education, sports and health with a score of 54%, while subjects with the least difficulty were natural sciences with a score of 10%.
Geometric Thinking Ability for Prospective Mathematics Teachers in Solving Ethnomathematics Problem
Authors: Hendriyanto A , Kusmayadi T A , Fitriana L 
Published: March 2021

Abstract
This study aims to identify, analyze, and describe the level of geometric thinking skills of students based on van Hiele’s theory. This study uses a qualitative descriptive approach with 63 respondents. Researchers as the main instrument and another used instrument are analytic geometry questions in the content fields of circles and ellipses based on ethnomathematics as well interview guidelines. The data analysis of this study is using qualitative technique data analysis by selecting 4 students from 63 subject populations with purposive sampling method. The results of this study showed (1) students’ geometric thinking ability is still low. (2) there were 39.7% students at pre-visualization level, 31.8% students at visualization level, 7.9% students at the level of analysis, 20.7% students at the level of informal deduction, 0% students are at the deduction and rigor levels. (3) students at the visualization level is able to visualize batik motif into geometric patterns, at the level of analysis students are able to identify what elements are known and what are needed to solve the problems, at the level of informal deductions students are able to make statements related to the relation between existing elements and able to prove the truth statement made.
Mathematical Literacy Skills Students of the Junior High School in Solving PISA-Like Mathematical Problems
Authors: Rahmawati W A , Usodo B , Fitriana dan L 
Published: March 2021

Abstract
This study aims to describe students of the junior high school mathematical literacy skills in solving PISA-like problems on number content. PISA-like items are problems created using dimensions in PISA. The method used in this study was descriptive qualitative. The research subject were students of the ninth-grade students in one of the integrated Islamic junior high school in Surakarta, which consisted of six students. The instruments used were tests, interviews and researchers. The results showed that the students’ mathematical literacy skills were classified as good for level 1 to 3 and low for level 4 and 5, and very low for level 6. This categorization was based on the number of students who answered the questions correctly at each level. Students in levels 1 to 3 were able to formulate mathematical situations and translate real-world problems into mathematical representations and then are able to choose the right solution strategy. However, when students faced level 4, 5, and 6 level questions, with a higher level of reasoning and complex problem situations, many students still faced difficulties. It has an impact on the students’ ability to determine strategies, make many mistakes, and not be able to answer the questions correctly.
The Development of Interactive Multimedia Based on Mathematics to Increase the Mathematical Connection Ability in Probability Learning
Authors: Purwanti  , Mardiyana  , Indriati D 
Published: March 2021

Abstract
This research aimed to develop an interactive multimedia-based mathematics lesson using Adobe flash on the probability material at SMK, to know the quality of media and increase student mathematical connection. This used the research development model 4-D. The instrument in this study is the learning media validation sheet, student’s response questionnaire to measure the media simplicity, and the question test to measure the media effectiveness. The results are described: 1) the validity level of mathematical interactive multimedia to improve the mathematical connection and the students’ learning achievements meet the valid criteria with a result of 89.17%. 2) The practicality level of mathematical interactive multimedia to improve the mathematical connection and achievements of a student’s learning meet the practice criteria with results 83.71%. 3) the effectiveness level of the mathematical interactive multimedia to improve the student’s mathematical connection meets the effectiveness criteria with results of 80,28%. The developed interactive mathematics multimedia can improve students’ mathematical connection skills in probability learning of 27.62% on the first indicator and 36.18% on the second indicator. So, the interactive mathematics multimedia that was developed can improve student’s mathematical connection skills in probability learning at SMKN 1 Wonoasri.
Generalized Space Time Autoregressive Integrated Moving Average with Exogenous (GSTARIMA-X) Models
Authors: Aulia N , Saputro D R S 
Published: March 2021

AbstractSpace time data is data that relates to events at previous times and locations. One of the models that used to analyze space time data is the Generalized Space Time Autoregressive Moving Average (GSTARMA) model. GSTARMA model uses parameters p andλkto represent the time order and spatial order respectively. Hence, this model can be called GSTARMA(p,λk). Because in fact there are more models with different parameters for different locations, GSTARMA(p,λk) model is more realistic. If space time data is not stationary, a different order is added so that the model becomes GSTARIMA(p, d,λk). In modelling sometimes the accuracy of the model can increase by other influence variables. These variables are named exogenous variables. The GSTARIMA model with exogenous variables is named the GSTARIMA-X(p, d,λk) model. This research aims to examine the model and its estimation of parameters. Model parameters are estimated using the Generalized Least Square (GLS) method. The method in this writing is literature study obtained from several articles, journals, and books that support in achieving research. The results of the study show that with the GLS method, parameter estimates can be obtained with the assumption of time order 1 and spatial order 1.
Generalized Cross Validation (GCV) in Smoothing Spline Nonparametric Regression Models
Authors: Maharani M , Saputro D R S 
Published: March 2021

Abstract
A nonparametric regression model is utilized if the the regression curve does not contain information about the accepted shape and accepted curve is exist in a function. If any curve is given without the limitation of a certain functional form, a rough and non-unique curve will result. The smoothing spline can be utilized to remove rough curves in some segments by following a curve pattern. An approach that combines nonparametric regression and smoothing spline is known as the smoothing spline nonparametric regression model. The problem in estimating is the selection and determination of smoothing parameters obtained by taking into the sum of knots used and the position of the knots so that the Generalized Cross-Validation (GCV) method is required. A study was conducted on the smoothing spline nonparametric regression model on GCV. The method used in research is a literature study obtained from some articles, journals, and books that support research achievement. The results showed that with the GCV method the minimum GCV value was obtained which would determine how well the smoothing parameters shown by the estimator did not change significantly even though the number and position of the knots varied.
Dynamic of Cytokine Storm in Human Inflammatory Response of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV)-Induced Disease
Authors: Wiraya A , Fitriana L , Triyanto  , Setiawan R 
Published: March 2021

Abstract
Infection of Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) in the human body is characterized by the detection of large amounts of the virus by cytokine as the response to inflammation. In the human body, there are two types of inflammatory responses by a cytokine called pro-inflammatory and anti-inflammatory cytokine. A non-dimensionalized mathematical model of the inflammatory response system has been constructed in the form of a system of differential equations, which consists of two variables and five parameters. The rate of pro-inflammatory and anti-inflammatory cytokine natural production are two important parameters that correlate with a chronic SARS-CoV infection called a cytokine storm. Varying these parameter values, some non-chaotic torus attractors were found in some numerical simulation with the initial value around the equilibrium point obtained by fixing parameter values at the Generalized Hopf bifurcation point. These phenomena show that in cytokine storm condition, fluctuation of pro-inflammatory and anti-inflammatory cytokines form some patterns which are complex, so that they are difficult to be predicted. Mesenchymal stem cells (MSC), chloroquine (CQ), and hydroxychloroquine (HCQ), which have an effect on pro-inflammatory and anti-inflammatory cytokine production, can be used to reduce the cytokine storm.