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All Journal Jurnal Penelitian dan Evaluasi Pendidikan Jurnal Sains dan Teknologi
Dewi Nurulhasni
Universitas Negeri Yogyakarta
Computer Science & IT Decision Sciences, Operations Research & Management Education

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Homemade BIOPLASTICS (Biodegradable Plastic From Cassava Peel Waste) with Analysis of the Effect of Glycerol and Cellulose Ratio on Tensile Strength, Elongation, and Thickness Dewi Nurulhasni; Suparno Suparno
JST (Jurnal Sains dan Teknologi) Vol. 12 No. 1 (2023): April
Publisher : Universitas Pendidikan Ganesha

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23887/jstundiksha.v12i1.51464

Abstract

Penelitian ini bertujuan untuk menganalisis rasio gliserol dan selulosa terhadap kekuatan tarik, elongation, dan ketebalan home made bioplaslits dengan pemanfaatan limbah kulit singkong. Penelitian ini menggunakan metode Casting. Tahap pembuatan bioplaslits yaitu pembuatan pati dari kulit singkong, pembuatan lembar bioplaslits, dan uji lembar bioplaslits. Uji kekuatan tarik (tensile strength) dan elongation menggunakan Universal Testing Machine (UTM) zwick/roell. Sedangkan ketebalannya menggunakan Thickness Gauge Mitutoyo. Lembar bioplaslits berupa lembaran tipis plastik yang dibuat menggunakan 5 gram pati dengan campuran  selulosa (0.4; 0.6; 0.8) gram dan gliserol (100%, 150%, 200%) ml yang telah diuji sifat mekaniknya. Hasil yang diperoleh adalah sifat mekanik kekuatan tarik bioplaslits terbaik ditunjukan oleh sampel kode C2G2 dengan konsentrasi 1,5 ml gliserol dan 0,8 gram selulosa dengan nilai kuat tarik rata-rata sampel 7.4808 (Mpa), sedangkan elongationnya paling tinggi ditunjukan pada sampel berkode C3G3 dengan konsentrasi 2,0 ml gliserol dan 0,8 gram selulosa dengan nilai rata-rata elongation sampel 6.2448%, adapun ketebalan paling tinggi ditunjukan pada sampel berkode C2G2, konsentrasi 1,5 ml gliserol dan 0,6 gram selulosa dengan nilai rata-rata ketebalan 269.066 (µm). Penambahan plasticizer gliserol dapat meningkatkan elongation, elastisitas, dan ketebalan lembar bioplaslits. Sedangkan penambahan konsentrasi selulosa dapat meningkatkan kuat tarik lembar bioplaslits.
Developing and implementing an instrument for assessing critical thinking and visual representations in learning Physics materials of Optical Instruments Dewi Nurulhasni; Eka Ayu Nurbaiti; Rosa Safirotun Nabila; Jumadi Jumadi
Jurnal Penelitian dan Evaluasi Pendidikan Vol 27, No 1 (2023)
Publisher : Graduate School, Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21831/pep.v27i1.53550

Abstract

This study aims to develop an assessment instrument to measure students' critical thinking and visual representation abilities in optical instrument material. This research and development (RD) employed the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) instructional model. This research develops a test instrument that has more specific stages so the ADDIE development stage is integrated with the development stage of the test instrument developed by Mardapi. The subjects in this study are grade XI students of State Madrasah Aliyah (MAN) 4 Bantul. This study produced a test instrument for measuring students' critical thinking and visual representation abilities, with high validity,and analyzed using Aiken's V. The items for assessing critical thinking and visual representation abilities were analyzed using the QUEST program with the following findings. (1) The analysis results of instrument validation using Aiken's V obtained an average Aiken's Value above 0.4 with high validity and moderate validity criteria so all items are valid. (2) The pre-test analysis on item estimates obtained MNSQ Infit in the range 0.77-1.30 and the value of outfit t ≤ 2 and in the MNSQ Infit case estimates in the range 0.77-1.30, so overall, the items matched to Rasch models. (3) Post-test analysis on item estimates obtained MNSQ Infit in the range 0.77-1.30 and outfit t value ≤ 2 and in case estimates MNSQ Infit in the range 0.77-1.30 so, overall, items are in accordance with Rasch models. (4) The reliability of the pre-test items is 0.92 while the reliability of the post-test items is 0.76. (5) The difficulty level of the items in the pre-test results shows that Question 10 is the most difficult while number 3 is the easiest, and in the post-test results, Question 8 is the most difficult while Question 6 is the easiest.
Co-Authors Eka Ayu Nurbaiti Jumadi Jumadi Rosa Safirotun Nabila Suparno Suparno