bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoscale Ni as a catalyst in MgH2 for hydrogen storage material
Authors: Rahwanto A , Ismail I , Nurmalita N , Mustanir  , Jalil Z 
Published: May 2021

Abstract
Supplying hydrogen to industrial users is now a major business around the world. One of the problems, before hydrogen can be implemented into today’s infrastructure is storing the hydrogen. In this report, we introduced a high-pressure milling method for preparing the MgH2 catalyzed with Ni nanoparticle. We have reactively milled the MgH2 + 2 mol % Ni, which has size ∼90 nm, under 100 bar of hydrogen. The structural changes during milling were characterized by XRD and high-resolution scanning electron microscopy. The hydrogen sorption properties were studied by gravimetric analysis. As the results, it was showed that the milling process reduced into 2 h. The sorption kinetics was proceeding 5.3 wt% of hydrogen around 5 min at 300°C, while desorption in 50 mbar was completed within 4 min. Preparing the Mg-based hydrides under high pressure with 2 mol% Ni in nanoscale as catalyst improved the hydrogen storage properties and decreased the milling time, as well.
Synthesis and characterization of nanoparticles Zn0.7Ni0.15Cu0.15Fe2O4 using the co-precipitation method
Authors: Sagala L P S , Humaidi S , Tarigan K , Soehada A M S , Sebayang P 
Published: May 2021

Abstract
This research was conducted to see the nanostructure and magnetic properties of nanoparticle Zn0.7Ni0.15Cu0.15Fe2O4. Zn0.7Ni0.15Cu0.15Fe2O4 has been successfully synthesized at 100°C using co-precipitation method. After synthesized, it was dried at 80°C. The second step, nanoparticle powder was characterised by X-Ray Diffraction (XRD) to determine the structure and phases formation of Zn0.7Ni0.15Cu0.15Fe2O4. FE-SEM was used to analyze the morphology of Zn0.7Ni0.15Cu0.15Fe2O4. To find out the elements contained in the sample, EDAX testing was conducted. X-Ray Diffraction (XRD) results showed that Zn0.7Ni0.15Cu0.15Fe2O4 in the shape of cubic spinel with the main peak at (311). There was a hematite phase (Fe2O3) with low intensity. Zn0.7Ni0.15Cu0.15Fe2O4 crystallizes well indicated by 2θ = 35.385°. The crystal size on the nano scale has been formed, which was 14.5087 nm. The FE-SEM results showed that the morphology of Zn0.7Ni0.15Cu0.15Fe2O4 was spherical and has agglomerated. The elements contained in these nanoparticles were Zn, Ni, Cu, Fe and O. There were no other impurities indicated from the EDAX test results.This indicated that the elements contained were already in accordance with the chemical formula. Magnetic hysteresis curves showed that Zn0.7Ni0.15Cu0.15Fe2O4 was softmagnetic.
Prediction of the height and period of sea waves in the coastal waters of Meulaboh, Aceh Province, Indonesia
Authors: Setiawan I , Yuni S M , Miftahuddin M , Ilhamsyah Y 
Published: May 2021

Abstract
This research examines the prediction of sea waves in the coastal waters of Meulaboh. The sea wave prediction are based on the 2015-2019 monsoons in the coastal waters of Meulaboh. The method used is an empirical equation that consist of wave parameters, i.e., significant wave height Hmo
and peak period Tp
. The sea wave prediction generate an average of the height and period of the sea waves of 0.7 m; 5 s in the Southwest direction. Based on the prediction, it shows that the sea waves in Meulaboh coastal waters are influenced by the Southwest wind that blows towards the coast from the Indian Ocean.
Extraction of kinetic energy in the part of Aceh Waters
Authors: Siregar A M , Ikhwan M , Haditiar Y , Wafdan R , Muhammad M , Ramli M , Muchlisin Z A , Rizal S 
Published: May 2021

Abstract
This research is a preliminary study regarding the extraction of kinetic energy from sea tides in Aceh’s waters. Aceh’s waters have a reasonably long coastline (> 2000 km), which has not been studied and utilized much. The extraction of kinetic energy from ocean tides is based on the speed of currents and turbines. Hydrodynamic verification is based on sea-level data from TPXO7.2 and Geospatial Indonesia Agency (GIA). The tidal data is sufficiently consistent with the verification data from TPXO7.2 and GIA. Based on the results, the model succeeded in accurately describing the hydrodynamics currents in the research domain based on comparative verification data. The velocity of M2 tidal flow in the waters of West Aceh is relatively low, particularly in the waters of Ulee Lheue is 0.018 m/s while in Calang waters, it is 0.025 m/s. The maximum tidal energy in Ulee Lheue waters is 9, 142 × 10−2 kW, with a daily power of 4.63 × 103 kW. In Calang waters, the maximum energy is 2, 449 × 10−1 kW, while the daily power is 1, 0167 × 104 kW. These results indicate that Calang Waters (Aceh Jaya district) had more significant potential for tidal currents and energy than Ulee Lheue Waters (Aceh Besar district).
The Improvement of students’ metacognition skills on natural science education using guided inquiry models
Authors: Huda K , Suyanta  , Priambodo Y A , Ardwiyanti D , Usman M , Alvionita D 
Published: May 2021

Abstract
This research aimed to find out the effectiveness of guided inquiry learning toward student metacognition skill, the level of metacognition skill, learning implementation and student response in science learning. The research was kind of pre-experimental research and using one pretest and postest group design. The population used student VII class of Junior High School 1 of Labang with sample on VII class. The data analysis technique used the Wilcoxon Non-Parametric test because the data were not normally distributed. The research instrument used a Metacognition Awareness Inventory (MAI) questionnaire. There was an influence of guided inquiry learning toward student metacognition skill by the signification level of MSI questionnaire was 0.006. Based on the level of significance of the data, it showed that learning using a guided inquiry model could improve students’ metacognition skills. There are three types of distribution of metacognition skills. The level of metacognition skill analysis was obtained from MAI questionnaire after learning as follows: Planning Skill was very good level, Monitoring Skill very good level and Evaluation Skill good level. The implementation of guided inquiry learning has a very high category. Student responses to the guided inquiry model obtained an average indicates a very interesting category.
Self-regulated learning of first-year students at physics education department, FKIP – Universitas Syiah Kuala
Authors: Herliana F , Farhan A , Elisa E , Evendi E , Mutiara W 
Published: May 2021

Abstract
This study examines the problem of how the criteria for self-regulated learning of first-year students at the Physics Education Department and aims to determine the self-regulated learning of freshman year students in the department. Quantitative research methods and descriptive approaches used in this study. A total of 61 students in 2017 became research subjects and obtained 83.60% of students believed in their abilities (criteria; very independent), 75.40% of students were satisfied with their effort (criteria; independent), 70.50% of students were able to make decisions and have learning initiatives (criteria; independent), and 62.30% of students are responsible for their studies (criteria; independent). That shows the Physics Education Department, FKIP Unsyiah class of 2018 has the self-regulated learning with independent to very independent criteria. The results of the study become a reference for the preparation and improvement of the curriculum.
Student responses toward worksheets based on stem approach through project-based learning model
Authors: Syukri M , Maghfirah S , Halim A , Herliana F 
Published: May 2021

Abstract
This study aims to determine student responses toward student worksheets based on the STEM approach through the PjBL model. The study was conducted on students of Class XI Science 4 at SMA Negeri 5 in Banda Aceh involving 27 students. The research method of the study used descriptive research which described student responses toward student worksheets based on the STEM approach through the PjBL model that has been previously developed. The data collection techniques utilized the student’s response questionnaire consisted of 10 statements and arranged using four alternative answers. The data processing of the research results used a Likert scale. Based on the result, the study obtained an average percentage of student responses of 85.09% with very good criteria. It showed that the students gave a positive response to student worksheets based on the STEM approach through the PjBL model.
Stability analysis of a diarrheal disease model elucidated multiple transmission pathways and infants as the most vulnerable
Authors: Fitriyah A 
Published: May 2021

Abstract
This study forms and analyzes a mathematical model of diarrheal disease.The model allows two pathways of disease transmission through infected people and water resources contaminated by pathogens that cause diarrhea. Babies are the most vulnerable to diarrhea, so that this modeling considers the difference in effective contact rate between susceptible babies and adults. Based on the assumptions, the model has formed a system of ordinary differential equations. A literature study is used to analyze the equilibrium and stability of it. Analysis found a disease-free equilibrium and an endemic equilibrium that are stable depends on a basic reproduction number (R0). The disease-free equilibrium is locally asymptotically stable when R0 < 1. It means diarrhea will disappear so that population is free from diarrhea for a long time. Furthermore, if R0 > 1 and several conditions are fulfilled, then the endemic equilibrium is also locally asymptotically stable. It means that for a long time, diarrhea will be an epidemic in population. Simulation of the model is given by using Matlab to verify the result of analysis.
A Rasch model analysis on the ability to analyze descriptive statistics: A case Study of FMIPA Universitas Syiah Kuala new students
Authors: Ferdhiana R , Santigana I , Abdurrahman F , Nurhasanah  
Published: May 2021

Abstract
Data literacy skills are essential in the current industrial 4.0 era. Data literacy skills include the ability to read and analyze data in a descriptive form. This study aims to measure the ability to analyze descriptive data and analyze the statistical analysis results of responses from new students of the Faculty of Mathematics and Natural Sciences, Universitas Syiah Kuala. The test instrument consisted of 29 questions divided into three parts: understanding, application, and analysis. The tool was tested with a time limit of 30 minutes to 436 respondents from 7 study programs at the Faculty of Mathematics and Natural Sciences. The average score obtained by students was 67.66, with a standard deviation of 12.48. The implementation of Rasch model provides a difficulty index ranging from-3.80 to 2.45, with a difficulty average approaching zero and a standard deviation of 1.4. The result concluded that the respondent’s ability to answer the questions is average.
Exploring the potential use of GeoGebra augmented reality in a project-based learning environment: The case of geometry
Authors: Lainufar  , Mailizar M , Johar R 
Published: May 2021

Abstract
The Curriculum in Indonesia requires teachers to be more interactive using one of the potential learning models, namely Project-Based Learning (PjBL) and technology integration. However, the existing learning instruments with that model are still superficial and limited in number. Augmented Reality (AR) as interactive technology is able to increase learning motivation and visual-spatial skills of students. This current study mainly aims to develop learning instrument with PJBL model and GeoGebra AR for geometry topic. We conducted this development study with the Plomp model. Yet, this paper merely reported the result from the prototyping stage and assessment phase. Six students were chosen for the small group trial, while for the field test, thirty-two students and a teacher were selected, and six validators participated. To collect data, this study utilized a questionnaire, an observation log, and an interview guide. The findings showed that the learning instrument has been valid since it was built on firm theory, and the components of the instrument were consistently connected and practical. The instrument is easy, appropriate, and effective to use in the learning process. Finally, students’ visual-spatial skills had been improved, and they responded positively to the learning with PjBL and GeoGebra AR.
Teachers’ perception of learning mathematics with medical waste management context
Authors: Mahlisa U , Zubainur C M , Anwar  
Published: May 2021

Abstract
This study aims to reveal teachers’ perceptions of mathematics learning in the context of medical waste management. The study was conducted by surveying 54 mathematics teachers in Banda Aceh using a questionnaire based on three perceptual indicators made by researchers, namely cognition, affection, and conation. The data were analyzed by classifying the answers based on perceptual indicators. The results showed that all the teachers had a good perception of mathematics learning by utilizing medical waste management as a learning context. They believe that the context of medical waste management would encourage students to contribute to protecting the environment and foster positive attitudes in students. Nevertheless, some teachers think that the context of medical waste management is a context that is difficult to use in learning mathematics. Also, the teachers are difficult to use medical waste management as a context for learning mathematics and increase their workload. This is due to a lack of knowledge about the use of the context of medical waste management in mathematics learning caused by the limited training on learning mathematics in the context of medical waste management and the unavailability of the teaching materials and learning tools needed, besides requiring more time.
Improving high school students’ critical thinking ability in linear programming through problem based learning assisted by GeoGebra
Authors: Rahman O , Usman  , Johar R 
Published: May 2021

Abstract
Critical thinking is one of the important abilities in learning mathematics, but the fact shows most high school students in Aceh have not developed the thinking skill yet. One of the causes is the mathematics learning that is carried out does not pay attention to critical thinking skills. This study aims to determine the increase in students’ critical thinking skills in linear programming learning through the Problem Based Learning (PBL) model assisted by GeoGebra Software in SMA Negeri 2 Teupah Barat. This research is a semi-experimental study with one group pre-test post-test design. The population in this study were all 24 students of class XI at SMA Negeri 2 Teupah Barat. A sample of 10 students was selected using the purposive sampling technique. The instrument used was the pre-test and post-test questions on critical thinking skills. The data were analyzed using SPSS 25 software including data description, normality test, paired sample t-test, and N-Gain score. The results showed that the use of the PBL model assisted by GeoGebra software can improve students’critical thinking skills on linear programming material at SMA Negeri 2 Teupah Barat with an average increase in students’ critical thinking skills of 50.05%, a minimum increase of 36.53% and a maximum increase of 63.57%.
Adapting solution: mathematical thinking abilities that facilitate problem solving ability in students
Authors: Septriwanto J V , Retnowati E , Rampean B A O 
Published: May 2021

Abstract
This article aims to present the results of the synthesis of adapting solutions in helping students solve mathematical problems. Adapting solution is a transfer strategy that adapts solutions provided in problem-solving. The selection of the right solution helps solve students’ mathematical problems by adapting to see the relationship between examples of identical problems or not identical to the given problem solutions. It is easy for students to adapt solutions to similar types of problems and the same solutions. However, what if students find two or more examples, one of which is more complicated than their assignment problem, and one of them is less complicated. Which should they choose as a more helpful guide? Alternatively, the difficulty is due to the inability to modify examples of simple problems to complex problems or vice versa. To answer the above problem formulation, in this article we will propose the use of learning strategies with adapting solutions and the proposed learning procedures of adapting solutions that are focused on facilitating students’ problem-solving abilities.
Analysis of students’ mathematical reasoning ability in geometry through distance learning
Authors: Novianda D , Darhim  , Prabawanto S 
Published: May 2021

Abstract
This study investigates the mathematical reasoning abilities of middle school students in geometry during the implementation of distance learning. This research is qualitative with a case study design by analyzing students’ mathematical reasoning abilities. The subjects in this study were 64 tenth grade senior high school students. The instrument in this study was a written test consisting of 5 questions. The questions were distributed to students by using google form due to the COVID-19 pandemic. Based on the research, it was obtained that the average mathematical reasoning ability of students was 64.5, which was categorized as a moderate category. Furthermore, the indicators of mathematical reasoning abilities that are mastered by students are (1) mathematical manipulation and (2) draw conclusions and compile evidence, while indicators of reasoning abilities that are less mastered by students are (1) draw conclusions from a statement, (2) assess argument validation, and (3) perform the generalization. These results indicate that the three indicators need to be improved in optimize students’ mathematical reasoning abilities.
Synthetisation of an affinity matrix (Procainamide Sepharose Cl-6b) for brain cholinesterase purification and separation source from Monopterus albus
Authors: Sabullah M K , Nordin N , Wahid D N A , Khalidi S A M , Abdulla R , Jawan R , Shukor M Y 
Published: May 2021

Abstract
Affinity chromatography for acetylcholinesterase; AChE namely Procainamide Sepharose CL-6B was synthesised through the coupling method between soluble procainamide hydrochloride immobilised by a cross-linked agarose size exclusion, sepharose CL-6B. 1, 4-butanediol diglycidyl ether plays a role in building up a productive and rigid connecting of a biospecific ligand (Procainamide hydrochloride) to an insoluble matrix (Sephacryl CL-6B). Local freshwater eel brain was extracted and centrifuge at high speed. The supernatant was collected, and seven different volumes were separately loaded on to the column for isocratic purification where 12 fractions were collected at the end of elution stage. This study shows 1000 μL of extractant; considered as the maximum volume to load onto the column. Lastly, a stepwise elution was performed with five different concentrations of NaCl, and each of 1 mL fraction was collected then assay for determination of enzyme activity and protein content. The data shows AChE was successfully purified with percentage recovery of 38 % after 21 purification fold. Kinetic study strengthens the data where the efficient coefficient ratio of ATCi was much higher compared to PTCi and BTCi at 3.03, 2.67 and 1.52 Vmax⋅Km
−1, respectively, prove that the collected fraction predominantly contained with AChE, which is a targeted enzyme to be used as a sensitive biosensor to detect the presence of carbamate and organophosphate contamination in the environment.
Characterization of Hydrochloric Acid Activated Natural Kaolin and its application as adsorbent for Mg2+
Authors: Wahyuni N , Zaharah TA , Ria R 
Published: May 2021

Abstract
Hard water can form deposits (scale) on pipe walls and operating units in industrial machines. One way to soften hard water is by using adsorbents to reduce the number of ions causing hardness, one of which is Mg2+. Kaolin is a natural mineral which has potential as an adsorbent. The ability of kaolin as an adsorbent can be enhanced utilizing activation. In this study, kaolin was chemically activated using HCl solution with varying concentrations, namely 4, 5, and 6 M. The activation was carried out by stirring kaolin with the activator solution for 24 hours. The adsorbent characterization was performed by the infrared spectrophotometer (FTIR) and the gravimetric method. The adsorption test for Mg2+ by activated kaolin was determined by adding 1g of adsorbent to 25 mL of 10 ppm Mg2+ solution with stirring rate 150 rpm. Furthermore, the adsorption contact time was varied, namely 30, 90, 150, and 180 minutes. The concentration of Mg2+was determined by a titration method using ethylenediaminetetraacetate (EDTA). The percentage of Mg2+ adsorbed was calculated as the concentration of Mg2+ adsorbed against the initial concentration. The results showed that kaolin activated by 6 M HCl could adsorb 68.9% of Mg2+ at the optimum contact time of 150 minutes. Activation of kaolin with HCl 6M can release organic impurities present in natural kaolin, which is thought to affect increasing its adsorption capacity for Mg2+.
The impact of the last stage of 4S TMD in chemistry books using knowledge building environment
Authors: Oktasari C , Anwar S , Munawaroh H S H , Fibrianto S 
Published: May 2021

AbstractThis research is a follow-up study which aims to describe how to develop a chemistry book in hydrocarbon materials based on KBE with the 4S TMD model. The 4S TMD model consists of four stages, namely selection, structuring, characterization and didactic reduction. This research will focus on the stage of characterization and didactic reduction. The Knowledge Building Environment (KBE) is a theory used to build values and knowledge in the environment to improve the quality of teaching materials. The values to be developed include attentiveness, caring, curiosity, critical, moderation, respect for the environment, respect for health and wisdom. The research uses design, development and evaluation research methods. In this article, we will discuss how the chemistry book is in the didactic characterization and reduction stages. The characterization stage finds difficult concepts that need to be reduced. Didactic reduction stage to reduce difficult concepts to be concrete and simple. The didactic reduction method is to return to the qualitative stage; neglect; use of explanations in the form of pictures, symbols, sketches and experiments; use of analogy; use of historical development levels; generalization; particularization; and ignoring different concept statements.
Identification phytochemical compound of ethanol and acetone extract of Cocoa Pods (Theobroma cacao L.) using GC-MS
Authors: Chusniasih D , Tutik T 
Published: May 2021

Abstract
Identification of phytochemical components of ethanol and acetone extract of cocoa pods (Theobroma cacao L) has been carried out. Cocoa pods samples were extracted with maceration method using two kind of solvent, ethanol 96% and acetone 80%. Phytochemical compound of extract then identified using qualitative and Gas Chromatography-Mass Spectrophotometry (GC-MS) method. From the results of identification, both ethanol and acetone extract contained flavonoid, alkaloid, tannin, and saponins. It was found that the ethanol extract of cocoa pods contained 36 types of compound, and acetone extract of cocoa pods contained 26 types of compounds. Three major component of ethanol extract were isopropyl palmitate, 2-furancarboxaldehyde, 5-(hydroxymethyl)-, and oleic acid. Three major component of acetone extract were n-Hexadecanoic acid, oleic acid, and octadecanoic acid, 2-(2-hydroxyethoxy)ethyl ester.