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Optical Characteristics Of Nano-Talc/TiO2 Thin Layer ; A Preliminary Study Vitrini, Nora; Jonuarti, Riri; Ratnawulan; Hidayat, Rahmat
Journal of Experimental and Applied Physics Vol 2 No 4 (2024): December Edition
Publisher : Department of Physics, Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/jeap.v2i4.81

Abstract

This study tested the effect of 50%:50% concentration nano-Talc/TiO2 on optical and photocatalytic properties thin layer activity. The goal is to understand how 50%:50% concentration affects absorption, reflection and transmission as as well as photocatalytic activity of thin layer. This research is experimental, starting with grinding Talc and TiO2, followed by dilution layer synthesis using the spin coat technique. Characterization includes cross-section morphology analysis using SEM, absorption, reflection, transmission and energy measurements slit with a UV-Vis DR spectroscope, as well as photocatalytic activity test. The research results show that the coating process managed to increase absorption by (92-98)% and energy band gap of 2.93 eV while reflection and transmission are reduced by (0.5-4)%, as well as the lowest rate of photocatalytic activity degradation rate of 0%, causing low ROS under light sunlight protective layer.
Sintesis dan Karakterisasi Material Beton Hidrofobik dan Self Healing Berbasis Mikroorganisme Maulida, Yulia; Ratnawulan; Riri Jonuarti; Amir, Harman
Jurnal Penelitian Pendidikan IPA Vol 9 No 12 (2023): December
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v9i12.5841

Abstract

The high water absorption of concrete causes the concrete to easily experience cracking and damage. One way to increase the durability of concrete is by adding microbes which can fill the micro cavities in the concrete with the resulting Calcium Carbonate (CaCO3) deposits. However, the weakness of using microorganisms is that they are unable to withstand high hydration heat. Therefore, by varying the temperature in this research, it is possible to determine the effect of the metabolism of the bacteria produced. This research was carried out to avoid damage by creating a hydrophobic and self-healing layer which helps increase the durability and strength of the concrete. The concrete sample made resembles a cube measuring 5 cm x 5 cm x 5 cm. The manufacturing materials are Portland cement, Otawa sand, distilled water and a mixture of E. coli bacteria. Heating was carried out using an oven at temperatures of 30, 60, 90, and 120 oC. Characterization testing was carried out using a Cpmreson machine, XRD and contact angle testing.
HOTS Assessment Development to Assess High School Physics Problem-Solving Skills Wahyuni, Veni; Ratnawulan; Mufit, Fatni
Jurnal Penelitian Pendidikan IPA Vol 11 No 10 (2025): October
Publisher : Postgraduate, University of Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/jppipa.v11i10.12880

Abstract

This study aims to develop an assessment instrument based on Higher Order Thinking Skills (HOTS) to assess high school students' problem-solving abilities in the subject of physics on renewable energy using the Plomp development model. The study was conducted through three main stages, namely (1) preliminary research to analyze needs (2) prototyping phase to design and validate the assessment instrument, and (3) assessment phase to conduct limited trials and product revisions. The assessment instrument was developed by containing essay questions based on real contexts that require critical, analytical, and creative thinking skills. The results of expert validation showed that the assessment was in the valid category with an average percentage score of 0.93. Trials on high school students showed that the assessment was able to measure variations in problem-solving abilities more comprehensively. Thus, this HOTS assessment based on the Plomp model is effective for evaluating physics problem-solving abilities.