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INDONESIA
Science and Technology Indonesia
Published by Universitas Sriwijaya
ISSN : 25804405     EISSN : 25804391     DOI : -
Core Subject : Science, Social, Engineering,
Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Environmental Science Materials Science & Nanotechnology Physics
An international Peer-review journal in the field of science and technology published by The Indonesian Science and Technology Society. Science and Technology Indonesia is a member of Crossref with DOI prefix number: 10.26554/sti. Science and Technology Indonesia publishes quarterly (January, April, July, October). Science and Technology Indonesia is an international scholarly journal on the field of science and technology aimed to publish a high-quality scientific paper including original research papers, reviews, short communication, and technical notes. This journal welcomes the submission of articles that covers a typical subject of natural science and technology such as: > Chemistry > Biology > Physics > Marine Science > Pharmacy > Chemical Engineering > Environmental Science and Engineering > Computational Engineering > Biotechnology Journal Commencement: October 2016
Arjuna Subject : -
Articles 551 Documents
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Modeling and Analysis Data Production of Oil, and Oil and Gas in Indonesia by Using Threshold Vector Error Correction Model Widiarti; Usman, Mustofa; Putri, Almira Rizka; Russel, Edwin
Science and Technology Indonesia Vol. 9 No. 1 (2024): January
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.1.189-197

Abstract

Data in the fields of finance, business, economics, agriculture, the environment and weather are commonly in the form of time series data. To analyze time series data that involves more than one variable (multivariate), vector autoregressive (VAR) models, vector autoregressive moving average (VARMA) models are generally used. If the variables discussed have cointegration, then the VAR model is modified into a vector error correction model (VECM). The relationship between short-term dynamics and deviation in the VECM model is assumed to be linear. If there is a nonlinear relationship between short-term dynamics and deviation, then a threshold vector error correction model (TVECM) can be used. The variables used in this research consist of oil production and Indonesian oil and gas production from January 2019 to March 2021. The research results show that the best model for data on oil production and oil and gas production is the TVECM 2 Regime model. Based on the TVECM 2 Regime model, further analysis, namely Granger causality and Impulse Response Function are discussed.
Molecular Spectroscopic (FTIR and UV-Vis) Analysis and In Vitro Antibacterial Investigation of a Deep Eutectic Solvent of N,N-Dimethyl Urea-Citric Acid Yudha S., Salprima; Angasa, Eka; Reagen, Muhamad Alvin; Kazi, Mohsin
Science and Technology Indonesia Vol. 9 No. 1 (2024): January
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.1.167-172

Abstract

The intriguing pursuit of environmentally friendly solvents with tailored properties for diverse applications is a focal point of numerous studies, encompassing precursor selection, thorough characterization, and the exploration of potential applications. The study aims to assess the physicochemical properties and antimicrobial activity of deep eutectic solvents (DES) produced from N,N-dimethyl urea (DMU) and citric acid (CA), highlighting differences from their individual precursors. Various mass ratio variations of (DMU, solid) and (CA, solid) (DMU:CA = 1.0:1.0; 1.0:1.5; 1.0:2.0; 2.0: 1.0; 1.5:1.0) have been tested to make DES solvents through the melt process. Both types of blends generally melt at a temperature of 80°C. The overall liquid resulting from the melting of solids was generally clear in color. Molecular analysis using an infrared spectrophotometer showed some insignificant shifts from one product to another, compared with DMU and CA as precursors. Likewise, analysis using a UV–Vis spectrophotometer, when the entire sample was dissolved in demineralized water (2 mg/mL), showed no difference in the spectrum. In addition, functional group analysis using a spectrophotometer showed some minor changes, mainly shifts in peaks due to changes in the DMU:CA ratio. This may be due to the interaction of the hydrogen donor and the hydrogen acceptor in DES. All samples showed absorption peaks in the ultraviolet region of 202-210 nm. The resulting DES application showed growth inhibitory activity for Staphylococcus aureus and Escherichia coli bacteria in all products produced. The same analysis of the two types of precursors used showed that only CA had activity, but DMU did not have similar activity.
Study on Crystal Structure, Surface Area, and Energy Gap Behaviors of Nanotitania Polymorphs Prepared Using Monoethanolamine Manurung, Posman; Maharani, Renita; Rahmayanti, Dita; Yulianti, Yanti; Junaidi; Marjunus, Ronius
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.345-353

Abstract

Polymorphous nanotitania samples were prepared from titanium butoxide (TTB) as a precursor using sol-gel processing in ethanol as a solvent, without and with monoethanolamine (MEA). The experiments used 5.25 mL TTB and MEA with varied volumes of 0.5, 1.0, 1.5, and 2.0 mL. The sample without MEA was specified as sample A, and the samples produced using MEA were specified as samples B, C, D, and E, respectively. All samples were calcined at 500 °C for 4 h and then collected data by X-ray Diffraction (XRD), the Brunauer-Emmett-Teller (BET) method used to analyze Surface Area Analyzer (SAA), Transmission Electron Microscopy (TEM), Raman Spectroscopy, and UV-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). The results of XRD characterization indicate that samples A and B form anatase phase, while samples C and D are composed of anatase, brookite, and rutile phases, and sample E is consisted of anatase and brookite phases with weight percentages of (94.53 ± 1.72) % and (5.47 ± 0.36) %, respectively. The presence of the three phases of titania is also confirmed by Raman spectroscopy analysis, which showed anatase peaks at 146, 197, 398, and 513 cm-1, brookite peaks at 245 and 402 cm-1, and rutile peaks at 319, 436, and 612 cm-1. According to XRD, the samples have the particle size in the range of 14-19 nm. A representative sample (sample C) was also characterized using TEM, revealing a particle size of 16.0 ± 0.3 nm. This representative sample revealed the largest surface area of 172.2 m2/g, as seen by BET, and the lowest energy gap of 3.03 eV.
Selective Removal of Anionic and Cationic Dyes Using Magnetic Composites Fitri, Erni Salasia; Mohadi, Risfidian; Palapa, Neza Rahayu; Susila Arita Rachman; Lesbani, Aldes
Science and Technology Indonesia Vol. 9 No. 1 (2024): January
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.1.129-136

Abstract

Water is one of the most basic human needs, and dyes are one of the sources of water pollution. Since adsorption has proven to be effective in removing contaminants, it is the most widely used technique. In this adsorption, a LDH Zn-Al /magnetic biochar composite was used for dye removal. Zn-Al LDH, magnetic biochar, and LDH Zn-Al/biochar magnetic composite were successfully synthesized, based on XRD and FTIR studies. XRD analysis of the Zn-Al LDH material shows diffractions of (003), (006), (101), (012), (015), (107), and (110) around the 2theta angle at 10.29°, 20.07°, 29.59°, 32.12°, 34.02°, 48.06°, and 60.16° which are characteristic of LDH materials. In magnetic biochar and LDH Zn-Al/magnet biochar composites diffraction (220), (311), (422) and (440) at 2theta around 24.9°, 35°, 63° and 68.4° in these materials indicate the characteristics of carbon-based materials from biochar. FTIR analysis showed the appearance of a vibration peak at 1404cm−1 indicating the presence of C H groups contained in biochar. The characteristic double-layer hydroxy (M-O) vibrations below 1000 cm−1 also indicated that the composite preparation process had been successful. The study’s results show that cationic dyes are more easily adsorbed than anionic dyes. Specifically, the LDH Zn-Al/Magnetic Biochar composite more extensively absorbs the cationic dye malachite green.
Network Pharmacology and Component Analysis Integrated Study to Uncovers the Molecular Mechanisms of Lansium parasiticum Bark Extract in Colon Cancer Treatment Mutiah, Roihatul; Briliana, Malich Septi Diajeng; Ahmad, Ananda Rizkia Azizah; Fauziyah, Begum; Janaloka, Nandana Adyuta; Suryadinata, Arief
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.314-324

Abstract

Side effects and risk of resistance are common consequences of colon cancer treatment based on chemotherapy. The medicinal plant originating in Indonesia, Lansium parasiticum bark extract (LPBE), has not been studied much. The purpose of this study is to identify the compounds present in LPBE and explain how the molecular mechanisms of the composite inhibit colon cancer cells. LC-MS/MS Liquid Chromatography Tandem Mass Spectrophotometry has been used to identify compounds in LPBE. The ADMET program is used to determine absorption profiles and bioavailability per oral. The tissue pharmacology approach uses Cytoscape 3.9.1, GeneCards, Disgenet, STRING 2.0.0, SRplot, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway to predict the molecular anti-cancer mechanisms of these compounds. In vitro validation using PyRx Autodock Vina 9.0 and Biovia Discovery Studio with BAX (PDB ID:2YXJ), BCL2 (P DB ID:2W3L) and STAT3 receptors (PDB ID:6NJS). A total of 17 active compounds were identified through LC-MS/MS. The moronic acid compound showed the highest levels of 14.29% followed by 4-Morpholineacetic Acid 12.2% and ursolic aldehyde 8.37%. Pharmacological network analysis showed that the compounder works on the EGFR tyrosine kinase resistance path by targeting the BCL2, BAX, STAT3 genes. The results of the in silico validation support the results of tissue pharmacology findings. Ursolic aldehyde, and Moronic acid showed a higher affinity to the three receptors. Therefore, Lansium parasiticum bark extract (LPBE) is recommended for further study as a candidate anti-cancer drug both in vitro and in vivo.
Robust-Set Covering Problem and Sensitivity Analysis to Determine The Location of Temporary Waste Disposal Sites Octarina, Sisca; Bangun, Putra Bahtera Jaya; Cahyono, Endro Setyo; Suprihatin, Bambang; Sarjani, Ita; Puspita, Fitri Maya; Yuliza, Evi
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.260-272

Abstract

The increasing population has resulted in a significant increase in the amount of waste. One effort that can be made to overcome the waste problem is to provide a Temporary Waste Disposal Site (TWDS). This research aims to optimize the TWDS in the Bukit Kecil sub-district, Palembang city, by formulating a Robust-Set Covering Problem (Robust-SCP) model and solving the model with the software. Sensitivity analysis is used to analyze the optimal solution. Bukit Kecil sub-district is the sub-district that has the highest number of TWDS in Palembang city. The robust-SCP model obtained 10 optimal TWDS. Therefore, this research recommends the Robust SCP model as the optimal solution for the determination of TWDS in the Bukit Kecil sub-district, namely TWDS Kartini Street, TWDS front of Starbucks KI Street, TWDS Merdeka Street, TWDS Illegal at 26 Ilir Market, TWDS Flat Block 35, TWDS Flat Block 49, TWDS Merdeka Women’s Prison, TWDS Musi Riverbank Park, TWDS Monpera, and TWDS Cinde Market, with the addition of TWDS Mayor’s Office in 22 Ilir village and TWDS Flat Block 01 in 23 Ilir village. The sensitivity analysis results in this study show that the solution remains optimal if the coefficient change is within the coefficient interval value.
Preparation of PAN/PVDF Nanofiber Mats Loaded with Coconut Shell Activated Carbon and Silicon dioxide for Lithium-Ion Battery Anodes Almafie, Muhammad Rama; Dani, Rahma; Riyanto; Marlina, Leni; Jauhari, Jaidan; Sriyanti, Ida
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.427-447

Abstract

Utilizing carbon materials derived from natural biomass holds significant promise for battery applications, owing to their low cost, abundant availability, and environmentally sustainable characteristics. However, graphite anode materials do not meet the demands of efficient batteries. Coconut shell waste has the potential to be used as activated carbon in energy storage anodes. By adding silicon dioxide (SiO2) to maintain structural stability and electrochemical reaction kinetics, the advantages of CCS can be maximized. Polyacrylonitrile/polyvinylidene fluoride (PAN/PVDF) composite polymer was used as a matrix to embed CCS/SiO2 and synthesize nanofibers via electrospinning. The resulting nanofibers had diameters ranging from to 575–707 nm, with cross-linked, porous, and beadless characteristics. Mechanical properties were measured by single-fiber micro tensile tests. The young modulus, tensile strength, and toughness of each nanofiber were successfully maintained at 13.7 ± 0.4 MPa, 34.4 ± 0.1 MPa, and 982 ± 10 kJ/m3, respectively, because of the presence of a β-crystal growth layer that facilitated efficient stress transmission. The reduction-oxidation process response had a potential difference of less than 1.286 V in the first cycle, whereas for the third and fifth cycles, it was maintained below 3.416 V. The lithium-ion diffusion coefficient was below 4.73×1013 cm2/s. Using the anode directly, as in lithium-ion batteries, provided a high capacity of 382 mAh/g after 200 cycles. Good cycle stability, with over 98% retention of the initial capacitance after 200 charge/discharge cycles, underscores its potential for application in lithium-ion batteries.
Identification of CO2 , SO2 , and a Mixture of Both Gases Using Optical Imaging Combined with Convolutional Neural Network (CNN) Salamah, Umi; Sakti, Setyawan Purnomo; Naba, Agus; Soetedjo, Hariyadi
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.371-379

Abstract

CO2 and SO2 gases are utilized in various industrial applications and are subjects of environmental research. However, these gases are considered toxic and pose dangers at certain concentrations. Therefore, it is crucial to monitor and control the exposure to these gases in the environment to prevent reaching hazardous levels that could endanger both humans and the environment. A non-contact detection and monitoring system is essential to minimize the adverse effects of direct gas exposure. In this research, a non-contact detection system for CO2, SO2, and mixed gases was developed using optical imaging analysis generated by infrared cameras. The images were captured using the FLIR Vue Pro-R infrared camera, with infrared absorbing gas sourced from a 50-watt tungsten lamp. Visual identification of these gases through optical imaging is challenging; however, this study successfully identified these gases using a Convolutional Neural Network (CNN). The CNN architecture used in this study is DenseNet (Densely Connected Convolutional Networks), comprising 169 convolution layers. The CNN model was trained and tested on experimental optical imaging data, categorized into three classes: CO2, SO2, and a mixture of gases. A total of 1030 optical imaging data points were utilized for training. Training was conducted using the AdamW optimization function over 28 epochs. The evaluation of results yielded accuracy, precision, recall, and F1-score metrics. The novelty of this study lies in the successful identification of CO2, SO2, and their mixture by the CNN model with an accuracy of 85%. Precision, recall, and F1-score values are all 0.85. These results indicate that the CNN model effectively distinguishes optical imaging of each gas (CO2, SO2, and their mixture) consistently and accurately. Consequently, it can be concluded that the CNN model performs well in distinguishing between these gases in optical imaging analysis.
Improvement of Solubility Usnic Acid Loaded on Mesoporous Silica SBA-15 and Physicochemical Characterization Fitriani, Lili; Azzahra, Cindy Maynia; Jessica, Adhitya; Hasanah, Uswatul; Zaini, Erizal
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.251-259

Abstract

Usnic acid, a secondary metabolite of lichen Usnea sp., has several pharmacological activities, but it is poorly soluble in water. This study aimed to improve the solubility and dissolution rate of usnic acid loaded in mesoporous silica SBA-15 at a mass ratio of 1:1. and evaluate its physical stability. Physicochemical characterization was carried out via the nitrogen adsorption desorption isotherm, differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, and powder X-ray diffraction (PXRD). Usnic acid-loaded SBA-15 was stored at 40 °C with various relative humidities (RH) and then analyzed by PXRD for the physical stability. Usnic acid adsorbed well in the pores of SBA-15, as shown by a decrease in the volume pore and surface area of SBA-15 according to the nitrogen adsorption. Moreover, usnic acid-SBA-15 showed a decrease in the degree of crystallinity according to PXRD analysis and no melting point based on DSC analysis. The FTIR spectrum of usnic acid–SBA-15 corresponds to the spectra of each raw material. The solubility of usnic acid increased 5.15 times after adsorbed on SBA-15. The dissolution rate also showed a significant increase (p < 0.05) from 19.51% to 84.27%. Usnic acid–SBA-15 was relatively stable at RH 75%. Thus, the adsorption of usnic acid on SBA-15 can increase its solubility, dissolution rate, and physical stability.
Enhanced Ammonium Adsorption from Aqueous Solutions Using Ethylenediaminetetraacetic Acid (EDTA) Modified Lampung (Indonesia) Natural Zeolite: Isotherm, Kinetic, and Thermodynamic Studies Abelta, Gita Aldira; Al Qadri, Latif; Febrina, Melany; Rajak, Abdul; Maulana, Sena; Asagabaldan, Meezan Ardhanu; Taher, Tarmizi
Science and Technology Indonesia Vol. 9 No. 2 (2024): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26554/sti.2024.9.2.224-234

Abstract

The environmental concern related to excessive ammonium in water bodies necessitates efficient and cost-effective removal techniques. This study investigated the modification of natural zeolite collected from the Tanggamus district of Lampung Province, Indonesia, with ethylenediaminetetraacetic acid (EDTA) to enhance its performance for ammonium adsorption from aqueous solution. The modified and natural zeolites were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), N2 adsorption-desorption isotherm, and scanning electron microscopy (SEM). Results indicated that the modification did not cause significant structural changes but increased the mesoporosity of the zeolites, which was beneficial for ammonium adsorption. The adsorption studies revealed that the EDTA modified zeolites consistently outperformed the natural zeolite and that the adsorption process was exothermic in nature. The Langmuir and Freundlich isotherm models fit the adsorption data well, indicating that the adsorption process occurs on both homogenous and heterogeneous surfaces. Thermodynamic studies confirmed that the adsorption process was exothermic and that the EDTA modification increased the spontaneity of the ammonium adsorption process. Overall, this study highlights the potential of EDTA-modified zeolites as an effective material for ammonium removal from aqueous solutions.

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