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Science and Technology Indonesia

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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

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Articles 551 Documents

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Preparation of Hydrochar from Salacca zalacca Peels by Hydrothermal Carbonization: Study of Adsorption on Congo Red Dyes and Regeneration Ability Mauizatul Hasanah; Alfan Wijaya; Fitri Suryani Arsyad; Risfidian Mohadi; Aldes Lesbani
Science and Technology Indonesia Vol. 7 No. 3 (2022): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Hydrochar of Salacca zalacca peels (HC-SP) is prepared by hydrothermal carbonization treatment of Salacca zalacca peels (SP) obtained from local fruits at Palembang, South Sumatera, Indonesia, with the resulting yield weight reaching 90%. Materials are characterized using the XRD diffraction, FTIR spectrum, and SEM-EDX. The XRD pattern shows the characteristics of the formation of amorphous compounds. The FTIR spectrum confirms the presence of functional groups O-H, C-H, C=C, and C-O. Data of SEM-EDX show that materials have heterogeneous morphologies, form aggregates, and in HC-SP materials there is an increase in carbon content from the initial material. The capacity of SP in the congo red (CR) adsorption process is 33.003 mg/g and increases to 133.333 mg/g in HC-SP. The maximum dye adsorbed was achieved at pH 4. The adsorption kinetics followed PSO with the equilibrium adsorption occurring at 90 minutes, and the adsorption isotherm followed the Langmuir isotherm with the value of R2 closer to the value of 1. A positive 4H value indicated that the adsorption is an endothermic process. In contrast, an 4S value suggested that the degree of irregularity in the adsorption process is small in large concentrations. Based on data regeneration ability, materials of SP and HC-SP can be used in the three cycles regeneration process of the CR adsorption process. The adsorption process of CR occurs physically and chemically based on enthalpy values and FT-IR data after being adsorbed with CR.

Catalytic Oxidative Desulfurization of Dibenzothiophene by Composites Based Ni/Al-Oxide Nur Ahmad; Alfan Wijaya; Amri; Erni Salasia Fitri; Fitri Suryani Arsyad; Risfidian Mohadi; Aldes Lesbani
Science and Technology Indonesia Vol. 7 No. 3 (2022): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

In the present study, composite layer double hydroxide-metal oxide (Ni/Al-TiO2 and Ni/Al-ZnO) was successfully prepared and used as catalyst of oxidative desulfurization of dibenzothiophene. Characterization of catalyst was used XRD, FTIR, and SEM-EDS. The structure of Ni/Al-LDH, TiO2, and ZnO in composite Ni/Al-TiO2 and Ni/Al-ZnO was consistent, which also indicated that the preparation of composite did not change the form of precursors. FTIR spectra of Ni/Al-TiO2 and Ni/Al-ZnO absorption band at 3398, 1639, 1339, 832, 731, and 682 cm−1. The catalysts have an irregular structure, TiO2 and ZnO adhere to the surface of Ni/Al LDH. The percent mass of Ti and Zn on the composite at 29.3% and 18.2%, respectively. The acidity of Ni/Al LDH increased after being composited with TiO2 and ZnO. The optimum reaction time, dosage catalyst, and temperature were 30 min, 0.25 g, and 50°C, respectively, and n-hexane as a solvent. The percentage conversion of dibenzothiophene on Ni/Al-LDH, TiO2, ZnO, Ni/Al-TiO2, and Ni/Al-ZnO were 99.44%, 91.92%, 95.36%, 99.88%, and 99.90%, respectively. The catalysts are heterogeneous system and the advantage is that can be used for reusability. After 3 times catalytic reactions, the conversion of dibenzothiophene still retains more than 80%, even Ni/Al-TiO2 and Ni/Al-ZnO composites still 97.79% and 98.99%, respectively.

Prediction of Ground Surface Deformation Induced by Earthquake on Urban Area Using Machine Learning Fathoni Usman; Nanda; Josaphat Tetuko Sri Sumantyo
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Earthquakes can inflict significant damage to structures and infrastructures. This paper presents a machine learning model to predict ground surface deformation (GDS) induced by earthquake events. The data on historical GSD is extracted from radar product of Synthetic Aperture Radar (SAR) data of one-year over five magnitude earthquakes that occurred within 200 kilometers of the Kota Padang Regency, West Sumatra. Building topology data of its footprint area, distance from shoreline, elevation, and coordinate were incorporated as the main features in the dataset. The earthquake parameters were taken from the USGS earthquake data catalog. Four machine learning algorithms of Neural Network (NN), Random Forest (RF), k-Nearest Neighbors (kNN), and Gradient Boosting (GB) are applied. The GSD from the trained models is predicted and compared with the measured GSD from the SAR’s product. The performances of proposed algorithms are evaluated in terms of the statistical index. A new dataset from the earthquake event in March 2022 is used to predict the GSD and further test the performance of the trained models. Overall, the four machine learning algorithms have outstanding performance, with a coefficient determinant of more than 0.9. The kNN algorithm outperforms compared to others in delineating the GSD. The trained models gave deficient prediction performance on the new dataset with a correlation coefficient of 0.228 predicted by the RF algorithm. Additional earthquake datasets and more unique features will improve the performance of the machine learning algorithms.

Novel Self-Nanoemulsifying Drug Delivery System of Single Bulb Garlic: Stability, Toxicity, and Antiinflammation in 3T3-L1 Cells Dewi Sekar Miasih; Yuslinda Annisa; Sri Rahayu Lestari; Hendra Susanto; Sunaryono
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Single bulb garlic (SBG) has the potential as an immunomodulator; however, it has low solubility and bioavailability. A lipid-based delivery system, that is, the self-nanoemulsifying drug delivery system (SNEDDS), offers a novel opportunity in drug delivery. SBG can be a suitable candidate for SNEDDS development. This research aims to describe the physical stability, toxicity test of the SNEDDS, and SNEDDS SBG potential as antiinflammation in 3T3-L1 cells. The SNEDDS is made with various ratios of concentrations of carrier oil, surfactants, and cosurfactants, namely, 0.50: 3.45: 0.96, and added with SBG extract (SBGE) of 20 mg/mL. The results of the response test of SNEDDS SBGE formulation indicate an average and standard deviation of emulsification time of 16.38±3.01 (second), pH 7.21±0.08, and transmittance of 98.40±0.23(%). The average nanoemulsion size is 14.333±0.416 nm, polydispersion index of 0.213±0.056, and zeta potential of -14.67±0.72 mV. The results of the physical stability test indicate no segregation, deposition, cracking, or creaming in all nanoemulsion samples and SNEDDS SBG. The MTT test in a dose of 62.5, 125, 250, 500, 100, 2000, and 4000 µg/mL suggests that the highest viability of the 3T3-L1 cells is at a dose of 2000 µg/mL, which is 97.83%±1.55%. Therefore, SNEDDS SBGE can be a potential candidate for oral preparation by increasing bioavailability and reducing toxicity in the 3T3-L1 cells. An antiinflammatory test on the TNF-???? and IL-1???? expressions influences the 3T3-L1 cells. the SNEDDS of SBGE has the potential to reduce the expression of TNF-???? and IL-1???? and increase IL-10 expression in the methylglyoxal-induced 3T3-L1 cells.

Properties and Bifunctional Catalytic Activity of Niobium-Doped Silica-Titania: Effect of Phosphoric Acid Treatment Siew Ling Lee; Jamilah Mohd Ekhsan; Chui Min Ling
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The effect of phosphoric acid treatment on the physical-chemical properties and catalytic activity of the niobium-doped silica-titania bifunctional catalyst was investigated. As part of the synthesis procedure to produce xPO4−/Nb/TiO2-SiO2, different concentrations of phosphoric acid (H3PO4) were used (x= 0, 0.05, 0.10, 0.15, 0.20, 0.25 M). As shown by XRD analysis, the samples synthesized using 0–0.20 M H3PO4 were in amorphous form, as featureless diffractograms were obtained, indicating the PO4− groups were dispersed homogeneously on the surface of Nb doped SiO2-TiO2. Due to the increased concentration of acid, other compounds were formed in the samples by reactions between PO4− and Nb and/or Ti. Additionally, UV-Vis DRS results indicated that the presence of the PO4− group accelerated the transformation of hydrated tetrahedral Ti species into isolated tetrahedral Ti species. An experimental investigation of the catalytic performance of the catalyst was conducted using 1,2-epoxyoctane as an oxidant for the epoxidation of 1-octene to 1,2-octanediol. It has been demonstrated that H3PO4 treatment was essential for oxidative and acidity active site formation. The current research findings strongly suggested that Nb-doped TiO2-SiO2 treated with 0.2 M H3PO4 was the most effective bifunctional catalyst in generating 1,2-octanediol.

CO2 Thermal Conductivity Detection in Gas Mixture for Concentration Measurement Using Bridge Configuration of Thermopiles Eko Satria; Melany Febrina; Mitra Djamal; Wahyu Srigutomo; Martin Liess
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

In this research, improvisation was carried out by modifying the market IR thermopile which functions as a thermal conductivity detector to measure the concentration of CO2 gas in the gas mixture. Four thermopiles are configured with a Wheatstone bridge with the aim of increasing the accuracy of the measurement system in detecting changes in CO2 concentration in the gas mixture (N2 and CO2). Using the bridge configuration of these four thermopiles, this measurement system can measure changes in CO2 concentration in small orders. The sensor developed is easy to manufacture, low cost, and has high linearity as evidenced by a correlation coefficient of 0.9943. From the experiments carried out, the sensor works quite accurately in detecting CO2 concentrations with the sensor’s sensitivity of -88.19 Volt/%, the detection range is 0% to 100%, and the RMS error value is 2.25.

Effect of Photosynthetic Pigment Composition of Tropical Marine Microalgae from Ambon Bay Navicula sp. TAD on Dye-Sensitized Solar Cell Efficiency Ivon Telussa; Eirene G. Fransina; Eka Rahmat Mahayani Anthonio Putera Lilipaly; Alfa Musa Imanuel Efruan
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Solar cells using dyes as sensitizers continue to expand. The synthetic dye used as a sensitizing material for solar cells has high production costs, difficult to find, and can cause environmental pollution. Photosynthetic pigments as sensitizers are considered to be the solution to this matter. In this research, we investigated the effect of photosynthetic pigments from the Navicula sp. TAD as a dye-sensitized material on the efficiency of Dye-Sensitized Solar Cell. To obtain high biomass, the Navicula sp. TAD was cultivated in a modified medium. Pigment extract from dry biomass using acetone, then continued with purification of the pigment using column chromatography techniques. Characterization of pigment by scanning the absorption pattern of visible rays, the fabrication of solar cells with TiO2 paste, and the photographic test of the solar cells filled with solar simulators. Navicula sp. TAD has photosynthetic pigments consisting of chlorophyll and carotenoid with 8.570 gmL−1 and 2.581 gmL−1, respectively. Solar cells using pigment crude extract, chlorophyll, and xanthophyll which TiO2 absorbs as electrodes, have efficiency values of 6.150×10−4, 3.482×10−3, and 4.117×10−3%, respectively.

Greedy Reduction Algorithm as the Heuristic Approach in Determining the Temporary Waste Disposal Sites in Sukarami Sub-District, Palembang, Indonesia Sisca Octarina; Fitri Maya Puspita; Siti Suzlin Supadi; Nur Attina Eliza
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Waste is one of the problems in Palembang, Indonesia. The amount of waste in Palembang increases proportionally to the population yearly and can adversely affect the community. Therefore, we determine the optimal temporary waste disposal site (TWDS) to optimize the problems. The set covering model is the proper model for solving the location and allocation problem. In this study, data on the distance between each TWDS is needed in the set covering modeling. The novelty in this research is developing the p-median problem model, which is formed from the optimal solution of the set covering location problem (SCLP) model. Palembang consists of 18 sub-districts, of which the Sukarami sub-district has the highest population density. This study discussed the determination of strategic TWDS in the Sukarami sub-district using the SCLP model, the p-median problem, and a heuristic approach, namely the greedy reduction algorithm in solving the model. Based on the solution of the p-median problem model with LINGO 18.0 and the p-median problem solved by the greedy reduction algorithm, only three strategic TWDS were found for the Sukarami sub-district. The study results recommend a review of the existing TWDS and particularly the addition of a TWDS in Sukodadi and Talang Betutu villages, respectively.

Synthesis and Study of Structural Properties of Calcium Oxide Nanoparticles Produced by Laser-Induced Plasma and its Effect on Antibacterial Activity Ibrahim Karim Abbas; Kadhim Abdulwahid Aadim
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

A LIBS technique was used to investigate the antibacterial activity of calcium oxide nanoparticles (CaO NPs). CaO NPs were prepared using a Q-switched Nd: YAG pulsed laser with a fundamental wavelength of 1064 nm at different energies (400-600 mJ) and constant frequency (6 Hz). A calcium powder sample was prepared after being pressed into a disc with a diameter of 1 cm. Analyzing X-ray diffraction (XRD) showed the crystalline structure of CaO NPs, crystalline size was 30.99±2 and 34.20±2.2 nm for laser energy 500 and 600 mJ. (FE-SEM) to reveal the topography of produced CaO NPs, the results showed a homogenous compact and dense surface with the formation of CaO NPs like flakes, cubes, and tubes. Atomic force microscopy (AFM) has shown that the CaO NPs were nanoscale and had a coordinated surface structures. The results also revealed the stabilizing zeta potential of the prepared CaO NPs, average (ZP) -18.3±1.6 mV in 600 mJ and -8.8±2.3 mV for 500 mJ. Different laser energies used in preparing CaO NPs resulted in the varying killing of the number of bacteria Klebsiella pneumoniae and Staphylococcus aureus bacteria. Complete bacterial inhibition or cell growth inactivation was found when the laser energy prepared for the CaO NPs was 600 mJ.

Development and Testing a Method for Retrieving Atmospheric Aerosol Optical Thickness based on the Solar Intensity from the Sun-photometer Data Jamrud Aminuddin; Raden Farzand Abdullatif; Mashuri; Bambang Hendriya Guswanto; Laras Toersilowati; Soni Aulia Rahayu; Hitoshi Irie; Hiroaki Kuze
Science and Technology Indonesia Vol. 7 No. 4 (2022): October
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The context of atmospheric aerosols is an indispensable aspect in studying the Earth’s radiation budget, climate change, and air quality. Therefore, the quality technique in retrieving aerosol parameters is important for a better understanding their characteristics. The precise calculating of the aerosol physical parameter in the planetary boundary layer will increase the accuracy of evaluation of their impact on environmental conditions. In several atmospheric corrections of optical remote sensing using satellite sensors, the AOT’s values play an important role in arranging a Look Up Table (LUT) for scattering parameters. Therefore, this study aims to develop a method for processing and correcting the sun-photometer data to obtain the original AOT in the planetary boundary layer. In AOT calculation using the sun-photometer data, the solar radiation at the extraterritorial of the atmosphere is determined using the Langley plot. Then, using the target data at the same season as the data for the Langley plot, the temporal change of AOT is estimated by employing the Lambert-Beer Law with some corrections. The major correction for the AOT’s values computation in the measurement target is the contribution of molecule from the local station and Ozone (O3) from the GOME-2 satellite data. The result has been compared with an independent measurement using a sky-radiometer at the same time as the sun-photometer monitoring. From the overall procedure, the AOT’s values have uncertainties at approximately 2-5% compared to the sky-radiometer. Therefore, the procedure will be useful for studying aerosol optical properties in the lower troposphere.

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