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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
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Indonesian Journal of Science and Technology
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2528-1410 - ISSN (Online) 2527-8045
Published by Universitas Pendidikan Indonesia Homepage  [12 journals]
  • Synthesis, Characterization, and Electrochemical Performance of Reduced
           Graphene Oxide-Metal (Cu,Zn)-Oxide Materials

    • Authors: Sugianto Sugianto; Ngurah Made Dharma Putra, Endah F. Rahayu, Wahyu B. Widayatno, Cherly Firdharini, Slamet Priyono, Didik Aryanto
      Abstract: The reduced graphene oxide (rGO) and metal (Cu,Zn)-oxide composites were prepared using a one-step hydrothermal technique. The role of (Cu,Zn)-oxide on the physical and electrochemical properties of the composite was investigated. The composite consists of various shapes of ZnO nanoflowers and micro-spheres, as well as Cu-oxide nanoflakes and octahedron-like shapes. The (Cu,Zn)-oxides were formed in between the rGO layers and observed in the rGO-ZnO, rGO-CuO, and rGO-CuO-ZnO composites. The presence of ZnO, CuO, and rGO within the composite structure is also confirmed by the analyses of crystal structure, microstructure, and surface functional groups. Some excess impurities remaining from the surfactant give considerable differences in the electrochemical performance of the composites. The specific capacitance values of the rGO, rGO-ZnO, rGO-CuO, rGO-(0.5CuO-0.5ZnO), and rGO-(0.25CuO-0.75ZnO) composites are 9.32, 58.53, 54.14, 25.21, and 69.27 F/g, respectively. The formation ofa double metal-oxide structure as well as their insertion into the rGO sheet can significantly improve the electrochemical properties of the supercapacitor.
      PubDate: Fri, 10 Mar 2023 08:36:57 +070
  • Green Route Synthesis of Amorphous Silica from Oil Palm Decanter Cake:
           From Literature Review to Experiments

    • Authors: Nursyahirah Abdul Rahim; Noorfidza Yub Harun, Anwar Ameen Hezam Saeed, Muhammad Roil Bilad
      Abstract: Numerous agricultural wastes are well-defined as low-cost sources and rich in silica content. The residue of oil palm wastes combustion seems a promising silica source and can be recovered through a straightforward method. In this study, the combustion followed by an alkaline extraction method was employed to extract high purity of silica. The oven-dried oil palm decanter cake (DOPDC) was heated at combustion temperatures of 600, 700, 800, and 900°C to produce OPDC ashes (OPDCA), followed by an alkaline extraction using 5M of NaOH solution. Thermogravimetric analysis (TGA) was used to observe the thermal behavior of DOPDC where the suitable combustion temperatures to produce silica ranged between 600 and 1000 ℃. X-Ray Fluorescence (XRF) analysis showed that silica contents were 31-36% after combustion, increasing to 76.95% after the chemical treatment. Moreover, the spherical shape of the silica was observed through electron microscope analysis. It was represented by the aggregation of silica after going through chemical treatment. The X-Ray Diffraction analysis also proved that the amorphous silica was produced, characterized by the hump-shaped spectrum. The infrared analysis confirmed that the silica had been successfully extracted from OPDCA by the presence of silica functional groups shown in the spectrum.
      PubDate: Wed, 28 Dec 2022 11:43:45 +070
  • Technological Aptitude and Sensitivity of Lactic Acid Bacteria Leuconostoc
           Isolated from Raw Milk of Cows: From Step-by-Step Experimental Procedure
           to the Results

    • Authors: Nora Hamdaoui; Yahya Rokni, Abdeslam Asehraou, Mohamed Mouncif, Zakaria Mennane, Abdelouadoud Omari, Asmae Sellam, Belkheir Hammouti, Mustapha Meziane
      Abstract: We demonstrated several technological aptitudes and sensitivity of lactic acid bacteria (Leuconostoc) isolated from the raw milk of cows. We explained the experiments in detail to get the reader to understand what kinds of technology can be used for testing bacteria. Lactic acid bacteria are used in the production of dairy products to increase their shelf life and improve their organoleptic and nutritional properties. Leuconostocs is a heterofermentative bacterium that produces lactic acid, acetic acid or ethanol, and carbon dioxide. A collection of 138 strains of lactic acid bacteria were isolated from the raw milk of cows in the region of eastern Morocco. 38 strains were identified as Leuconostocs. Their subspecies are 16 Mesenteroides, 11 Dextranicum, and 11 Cremoris. Our study was interested in the technological aptitude of this genus looking for the production of dextran and growth in milk with additional sunflower dye, as well as the acidifying, flavoring, thickening, coagulating, proteolytic activity in solid medium and Lipolytic activity. This work also consisted of studying the profile of the resistance and the sensitivity of these strains to antibiotics.
  • Sustainable Production-Inventory Model with Multi-Material, Quality
           Degradation, and Probabilistic Demand: From Bibliometric Analysis to A
           Robust Model

    • Authors: Dana Marsetiya Utama; Imam Santoso, Yusuf Hendrawan, Wike A. P. Dania
      Abstract: An adequate sustainable production inventory model is expected to represent complex real-life cases involving fuel, emissions, and electricity costs as well as multi-materials, quality degradation, and probabilistic demand. Therefore, this study was conducted to develop this kind of model to determine the number of raw material shipments (), production cycle time (), and the number of finished goods delivered (n) to maximize the Expected Total Profit (ETP). The proposed model is based on a bibliometric literature analysis of the sustainable production-inventory problem which is visualized using the VOSviewer. Moreover, a sophisticated Harris-Hawks Optimization (HHO) algorithm was proposed to solve the problems identified in the sustainable production inventory model optimization. It is also important to note that three numerical cases were provided to evaluate the performance of the algorithm. The findings showed that the suggested HHO method outperforms the Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) in maximizing ETP and this means it is better for ETP optimization. It was also discovered from the sensitivity analysis that an increase in the rate of quality degradation (k) led to a reduction in both the ETP and T.
  • Design of Robust Control for Vehicle Steer-by-Wire System

    • Authors: Suha S. Husain; Mina Qays Kadhim, Abdulkareem Sh. Mahdi Al-Obaidi, Alaq F. Hasan, Amjad J. Humaidi, Dwi Novia Al Husaeni
      Abstract: This study presented the design of a robust controller based on Integral Sliding Mode Control (ISMC) for controlling the Vehicle Steer-by-Wire (VSbW) system. The dynamic model of the VSbW system is first developed and then the design of ISMC has been conducted via the states of the system. The VSbW system has been described by two terms; one term represents the nominal model, which is free from nonlinearities, and the other term lumps the uncertainties in system parameters. The integral sliding mode controller has been designed for controlling the VSbW system. The control design consists of two parts. The first control part has addressed the nominal term of the system, while the second control part tackles and eliminates the effects of uncertainties and perturbation due to the uncertain term of the system. The numerical simulation has been conducted to show the robustness of ISMC and its capability to reduce the chattering effect in the control signal. In addition, a comparison study in performance has been conducted between the proposed controller and other controllers in the literature. We also carry out bibliometric analysis to see research trends. Based on our analysis, the number of publications regarding the keywords "controller", "steer", and "wire system" changes every year (25 (2018), 56 (2019), 51 (2020), 71 (2021), and 61 (2022)).
  • Phytochemical Profile and Biological Activities of Ethylacetate Extract of
           Peanut (Arachis hypogaea L.) Stems: In-Vitro and In-Silico Studies with
           Bibliometric Analysis

    • Authors: Idin Sahidin; N. Nohong, Marianti A. Manggau, A. Arfan, W. Wahyuni, Iren Meylani, M. Hajrul Malaka, Nur Syifa Rahmatika, Agung W. M. Yodha, Nur Upik En Masrika, Abdulkadir Kamaluddin, Andini Sundowo, Sofa Fajriah, Rathapon Asasutjarit, Adryan Fristiohady, Rina Maryanti, Nur Indri Rahayu, M. Muktiarni
      Abstract: The utilization of the stems, leaves, and hulls of peanuts (Arachis hypogea) is not as popular as the seeds. This study aimed to investigate the chemical contents and pharmacological activities of A. hypogaea stems in-vitro and in-silico. This study was also completed with bibliometric analysis. The methanol extract (ME) was reextracted by ethylacetate to get ethyl acetate extract (EAE). The chemical contents of EAE were analyzed by phytochemical screening, Liquid Chromatography-Mass Spectroscopy (LC-MS/MS), TPC (Total Phenolic Content), and TFC (Total Flavonoid Content). In-vitro and in-silico studies evaluated antioxidant potency, toxicity, and cytotoxicity toward MCF-7 cell lines. The results showed that EAE contained terpenoids, flavonoids, alkaloids, and phenolics which were supported by LC-MS/MS data. The EAE was categorized as a very strong antioxidant and moderately active in both cytotoxicity and toxicity.
  • Biochar from Agricultural Waste for Soil Amendment Candidate under
           Different Pyrolysis Temperatures

    • Authors: Abdul Mutolib; Ali Rahmat, Endra Triwisesa, H. Hidayat, Hari Hariadi, Kiki Kurniawan, S. Sutiharni, S. Sukamto
      Abstract: Indonesia as an agricultural country produces and consumes a huge amount of fruits. One of the popular fruits is durian (Durio zibethinus), which can create issues with the high amount of durian seeds. Durian seeds can be fermented quickly. Thus, if they are not processed immediately, it causes pollution to the environment, particularly an odor issue. One of the waste management is to convert durian seed waste into biochar, an ameliorant agent to improve soil quality. This study aims to analyze the physicochemical properties of durian seed-derived biochar under different pyrolysis temperatures. The results showed that the increases in the temperature allowed the creation of more porosity in the biochars, which is due to chemical structure and crystallinity arrangement. This is confirmed by the increases in surface area and total pore volume also decreases in particle size. The change in the chemical structure can be verified by the decreases in the biochar yield. The produced biochar from fruit seeds has excellent carbon content and elemental components such as potassium, magnesium, phosphor, and sulfur, informing prospective fruit seeds as a soil amendment fertilizer
  • e-book Multimedia Animation Implementation on Concept Mastery and
           Problem-Solving Skills of Crystal Structure Subjects in Engineering
           Materials Course

    • Authors: Amay Suherman; Mumu Komaro, A. Ana
      Abstract: This research is motivated by students’ difficulties in understanding abstract, complex, and dynamic concepts in the learning process of the Engineering Materials course. The course is very important because it is indispensable for advanced study program expertise courses. The purpose of the research is to analyze the impact of using the e-book Multimedia Animation (e-MMA) in the learning process of engineering materials courses on improving students’ learning outcomes in the crystal structure subject. The research used an experimental method with a randomized control group pretest-posttest design. Two groups were assessed from two classes in Engineering Department randomly selected as the research sample. The subject that becomes the focus of this study is Crystal Structure to understand Concept Mastery and Problem-solving aspects. Thus, there will be two competency data from the research results. The application of e-MMA in the learning process of engineering materials can improve student learning outcomes with an increase in the high category N-gain. The E-MMA is very effective in solving the problems of students in understanding crystal structure subject in engineering materials courses because of their ability to provide images and animations of abstract objects. Students can easily understand the concepts and formulas that exist in the crystal structure subject of engineering materials course
  • Bifunctional CaCO3/HY Catalyst in the Simultaneous Cracking-Deoxygenation
           of Palm Oil to Diesel-Range Hydrocarbons

    • Authors: Rosyad Adrian Febriansyar; Teguh Riyanto, I. Istadi, Didi D. Anggoro, Bunjerd Jongsomjit
      Abstract: Palm oil is a promising raw material for biofuel production using the simultaneous catalytic mechanism of the bifunctional cracking-deoxygenation reactions. Through the cracking-deoxygenation process, the chains of palmitic acid and oleic acid in the palm oil were converted to diesel-range hydrocarbons. The combination effects of CaCO3 and HY zeolite enhanced the bifunctional catalytic cracking-deoxygenation of palm oil into biofuel, because of the increasing acid and basic sites in the catalysts due to the synergistic roles of CaCO3 and HY. The introduction of CaCO3 on HY zeolite generated both a strong acid and strong basic sites simultaneously on the designed catalyst, which supports the bifunctional mechanisms of hybrid cracking-deoxygenation, respectively. The CaCO3 impregnated on the HY catalyst has a synergistic and bifunctional effect on the catalyst supporting cracking-deoxygenation reaction mechanisms as mentioned previously. The deoxygenation reaction required the bifunctional strong acid and strong basic sites on the CaCO3/HY catalyst through decarboxylation, decarbonylation, and hydrodeoxygenation reaction mechanisms. Meanwhile, the cracking reaction pathway was supported by the strong acid sites generated on the CaCO3/HY catalyst. In other words, the high acidity strength promotes diesel selectivity, whereas the high strength of basicity leads to the deoxygenation reaction.
  • Predicting Consumption Intention of Consumer Relationship Management Users
           Using Deep Learning Techniques: A Review

    • Authors: Eshrak Alaros; Mohsen Marjani, Dalia Abdulkareem Shafiq, David Asirvatham
      Abstract: Consumer/customer relationship management (CRM) can potentially influence business as it predicts changes in people’s perspectives, which could impact future sales. Accordingly, advancements in Information Technology are under investigation to see their capabilities to improve the work of CRM. Many prediction techniques, such as Data Mining, Machine Learning (ML), and Deep Learning (DL), were found to be utilized with CRM. ML methods were found to dominate other approaches in terms of the prediction of consumers’ intention to purchase. This review provides DL algorithms that are mostly used in the last five years, to support CRM to predict purchase intention for better product sales decisions. Prediction criteria related to online activities and behavior were found to be the most inputs of prediction models. DL approaches are slowly applied within purchase intention prediction due to their advanced capabilities in handling large and complicated datasets with minimum human supervision. DL models such as CNN and LSTM result in high accuracy in prediction intention with 98%. Future research uses the two algorithms (CNN, LSTM) compiled to make the best prediction consumption in CRM. Additionally, an effort is being made to create a framework for predicting purchases based on many DL algorithms and the most pertinent characteristics.
  • How to Calculate and Measure Solution Concentration using UV-Vis Spectrum
           Analysis: Supporting Measurement in the Chemical Decomposition,
           Photocatalysis, Phytoremediation, and Adsorption Process

    • Authors: Asep Bayu Dani Nandiyanto; Risti Ragadhita, Muhammad Aziz
      Abstract: UV-visible (UV-Vis) spectroscopy is a powerful instrument for qualitative investigation and quantitative detection of pollutants in water. UV-Vis spectrophotometry is an analytical method using the concept of transmission of light in UV and Visible wavenumber. Generally, compounds can be identified using UV-Vis Spectrophotometry, based on the concept of light absorption, specifically for compounds with a chromophore group and an auxochrome group. Although the utilization of UV-Vis spectrum analysis has been well-documented, no information regarding detailed step-by-step measurement for examining detailed quantitative analysis, particularly in determining the concentration of an analyte in an aqueous solution sample. Here, this study explores the idea and application of UV-Vis technology in water quality detection, including guidelines for determining the concentration of the sample in an aqueous solution. To support the analysis, we also added practical examples for understanding concentration during the organic decomposition. This paper is intended to be useful for researchers and students in understanding UV-Vis spectrophotometry when analyzing chemical composition during chemical decomposition, photocatalysis, phytoremediation, and adsorption analysis.
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