Garuda - Garba Rujukan Digital

All

Science and Technology Indonesia

JSTI
Website

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 13 Documents

1 2

Search results for , issue "Vol. 6 No. 3 (2021): July" : 13 Documents clear

Seagrass Cholorophyll-a, Biomass and Carbon Algorithms Based on the Field and Sentinel-2A Satellite Data at Karimunjawa Island, Indonesia Agus Hartoko; Yoan Teresia Sembiring; Nurul Latifah
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Chlorophyll-a in seagrass biomass is functioned for the photosynthetic process and store the organic carbon in their biomass of the leaf, rhizome, and root. Ecologically has functioned as blue carbon in reducing global warming adaptation and mitigation strategy. The study aimed to explore seagrass species, chlorophyll-a content, biomass and carbon stock at Karimunjawa Island. Develop algorithms of the Sentinel-2A satellite data based on field seagrass chlorophyll-a, biomass and carbon and at Pokemon and Bobby beach Karimunjawa Island. Four species of seagrass found at Bobby and Pokemon beach are Holodule pinifolia with a density of 160.44 ind.m−2 , Enhalus acoroides with 26.22 ind.m−2, Halophila ovalis with 6.67 ind.m−2 and Thalassia hemprichii with 4.44 ind.m−2.The lowest seagrass chlorophyll-a is 5.854 mg.ml−1 found in H. pinifolia and the highest is 20.819 mg.ml−1found in E. acoroides at Pokemon beach. The range of seagrass chlorophyll-a at Bobby beach was 3.485 - 14.133 mg.ml−1 in T. hemprichii. The smallest individual biomass dry weight was found in T.hempirichii with 1.32 g.dry.weight per individu, and the biggest in E.acoroides with 6.98 g.dry.weight per individu. The highest seagrass biomass at Pokemon beach was in E. acoroides with 236.93 g.m−2 which has a wide leaf morphology and the lowest in H. pinifolia with 75.91 g.m−2 with the smallest leaf morphology. The range of seagrass biomass at Bobby beach is 97.62 - 264.48 g.m−2 which is dominated by T.hempirichii. The range of seagrass carbon was 109.63 - 136.82 gC.m−2at Pokemon beach, and in the range of 95.00 - 114.01 gC.m−2 at Bobby beach. Algorithm of seagrass chlorophyll-a = -36.308 (B3/B4)2 – 140.41(B3/B4) + 83.912 ; biomass = -7028.3 (B3/B4)2 + 14948 (B3/B4) – 7764.4; carbon = -17.529(B2/B3)2 + 143.82(B2/B3) – 5.3362 for Pokemon beach. Algorithm of chlorophyll-a = 455.02 (B2/B4)2 + 823.72 (B2/B4) + 375.48; biomass = -14699 (B3/B2)2 + 28395(B3/B2) – 13537; and carbon = - 0.001(B3/B4)2+ 0.209(B3/B4) - 10.203 for Bobby beach. The use of Band-2 (0.490 ????m), Band-3 (0.560 ????m) and Band-4 (0.665 ????m) Sentinel-2A satellite data in the development of seagras chlorophyll-a, biomass and carbon algorithm was found to be significant.

Structure and Dynamics of Curcumin Encapsulated Lecithin Micelles: A Molecular Dynamics Simulation Study Lukman Hakim; Diah Mardiana; Urnik Rokhiyah; Maria Lucia Ardhani Dwi Lestari; Zubaidah Ningsih
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Curcumin is a natural product with potential pharmaceutical applications that can be augmented by drug delivery technology such as nano emulsion. Our study focuses on microscopic structural and dynamics response of curcumin encapsulation in micellar system with lecithin as a natural surfactant under variations of composition and temperature using molecular dynamics (MD) simulations. The results highlight the self-assembly of lecithin micelle, with curcumin encapsulated inside, from initial random configurations in the absence of external field. The variation of composition shows that lecithin can aggregate into spherical and rod-like micelle with the second critical micelle concentration lies between 0.17-0.22 mol dm−3. The radial local density centering at the micelle center of mass shows that the effective radius of micelle is indeed defined by the hydrophilic groups of lecithin molecule and theencapsulated curcumin molecules are positioned closer to these hydrophilic groups than the innermost part of the micelle. The spherical micelle is shown to be thermally stable within the temperature range of 277-310 K without a perceivable change in the spherical eccentricity. The dynamics of micelle are enhanced by the temperature, but it is shown to be insensitive to the variation of lecithin-curcumin composition within the studied range. Simulation results are in agreement with the pattern obtained from experimental results based on particle size, polydispersity index, and encapsulation efficiency.

Determining the Credit Score and Credit Rating of Firms using the Combination of KMV-Merton Model and Financial Ratios Norliza Muhamad Yusof; Iman Qamalia Alias; Ainee Jahirah Md Kassim; Farah Liyana Natasha Mohd Zaidi
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Credit risk management has become a must in this era due to the increase in the number of businesses defaulting. Building upon the legacy of Kealhofer, McQuown, and Vasicek (KMV), a mathematical model is introduced based on Merton model called KMV-Merton model to predict the credit risk of firms. The KMV-Merton model is commonly used in previous default studies but is said to be lacking in necessary detail. Hence, this study aims to combine the KMV-Merton model with the financial ratios to determine the firms’ credit scores and ratings. Based on the sample data of four firms, the KMV-Merton model is used to estimate the default probabilities. The data is also used to estimate the firms’ liquidity, solvency, indebtedness, return on asset (ROA), and interest coverage. According to the weightages established in this analysis, scores were assigned based on those estimates to calculate the total credit score. The firms were then given a rating based on their respective credit score. The credit ratings are compared to the real credit ratings rated by Malaysian Rating Corporation Berhad (MARC). According to the comparison, three of the four companies have credit scores that are comparable to MARC’s. Two A-rated firms and one D-rated firm have the same ratings. The other receives a C instead of a B. This shows that the credit scoring technique used can grade the low and the high credit risk firms, but not strictly for a firm with a medium level of credit risk. Although research on credit scoring have been done previously, the combination of KMV-Merton model and financial ratios in one credit scoring model based on the calculated weightages gives new branch to the current studies. In practice, this study aids risk managers, bankers, and investors in making wise decisions through a smooth and persuasive process of monitoring firms’ credit risk.

Tablet Formula Optimization From Helminthostachys Zaylanica Extract Using A Simplex Lattice Design Fitrya Fitrya; Najma Annuria Fithri; Budi Untari; Aprililianti
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Helminthostachys zeylanica extract has pharmacological activities such as antioxidant, antiinflamatory, and antihyerucemia. This extract is nontoxic substance from the acute and subchronic toxicity tests. This extract has a potency to be formulated into tablet dosage forms. This study aims to optimize a tablet formula from Helminthostachys zeylanica extract. Disintegrant and binder concentrations were independent variables, while physical properties and dissolution time of the tablets were dependent variables. The tablet was prepared by a wet granulation method. Formula was optimized by Simplex Lattice Design. Physicochemical propertiesof granule, physical properties and dissolution of tablet were then analyzed with One Way ANOVA (p = 0.05). Based on granule analysis, specification of physicochemical parameters, such as hausner’s ratio, compressibility index, flowability, repose angle, and water content, met standard British Pharmacopeia. In addition, the starch and PVA concentrations influenced thickness, weight variation, hardness, friability, disintegration time and dissolution of the tablets (p <0.05), except for friability (p> 0.05). Based on this study, the starch and PVA concentrations for the optimum tablet formula were 19.5% and 1.05%, respectively.

Utilization of Activated Charcoal from Sawdust as an Antibiotic Adsorbent of Tetracycline Hydrochloride Gatut Ari Wardani; Ega Maulana Qudsi; Anindita Tri Kusuma Pratita; Keni Idacahyati; Estin Nofiyanti
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The use of activated charcoal from sawdust as an adsorbent of tetracycline hydrochloride compounds has been successfully carried out. Sawdust activated charcoal was carbonized at 450°C for 40 minutes with a charcoal size of 100 mesh and activated using H3PO4 solution. The characteristics of active sawdust charcoal showed that water content, iodine adsorption, and methylene blue adsorption had met SNI 06-3730-1995 regarding technical activated charcoal. Testing the morphology of charcoal using a Scanning Electron Microscope showed that the charcoal pores were opened through the activation process. In the functional group analysis test using infrared spectroscopy, the active group contained in charcoal after being activated contained carbon atoms that were purer than sawdust. The adsorption process of tetracycline hydrochloride using sawdust activated charcoal is known to follow Ho orPseudo second-order (K = 0.0039 g/mg.min), while the adsorption isotherm follows the Langmuir equation, KL = 0.0076 L/mg and adsorption capacity amounting to 242.1307 mg/g. Thermodynamically, the adsorption process occurs not spontaneously with a Gibbs free energy value of 120.8949 kJ/mol and occurs by chemisorption.

Silica from Natural Sources: a Review on the Extraction and Potential Application as a Supporting Photocatalytic Material for Antibacterial Activity Annisa Luthfiah; Yusi Deawati; M. Lutfi Firdaus; Iman Rahayu; Diana Rakhmawaty Eddy
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Silica has become a popular material due to its high abundance and many advantages in various fields. This material can be produced synthetically and extracted from nature with resultant advantages in the application of green production. Therefore, this article deals with the form of silica extracted from quartz sand, leaves, and agricultural wastes found in nature. The extraction process from various sources would be described using thermal, biological, and chemical methods. This review also highlights the potential application of silica as a photo catalytic antibacterial-supporting material and discusses its role in increasing the effectiveness of the process. The discussion was continued with research on this procedure, where synthetic auxiliary materials were compared to the extracted silica. Furthermore, results obtained indicated that the extracted material had very good potential as a photocatalyst adjunct in its application in the antibacterial field.

Antibacterial Activity of Endophytic Fungi from Sembukan (Paederia foetida L.) Leaves Hary Widjajanti; Christina Vivid Handayani; Elisa Nurnawati
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The antibiotic resistance of phatogenic bacteria has become a serious health problem and has encouraged the search for novel and effective antimicrobial metabolites. Meanwhile, endophytic fungi have great potential as a natural source for antimicrobial agents. The endophytic fungi that live in plant tissue produces secondary metabolites which potentially act as an antibacterial compound. The isolation of fungi for antibacterial sources reduces the large amount of plant as a source of antibacterial agents. Hence, this study aims to obtain endophytic fungi isolates from Paederia foetida L. that are capable of producing secondary metabolites as antibacterial, carry out in vitro tests to verify the antibacterial properties of secondary metabolites of the Paederia foetida L. endophytic fungi, and identify the potential of Paederia foetida L. endophytic fungi in producing antibacterial compounds. The antibacterial activity was tested against Escherichia coli ATCC8739 and Staphylococcus aureus ATCC6538 while seven isolates of endophytic fungi that potentially produced antibacterial were obtained from Sembukan (P. foetida L.). The results showed that antibacterial activities of SL1, SL4 and SL6 secondary metabolites against S. aureus ATCC6538 and E. coli ATCC8739 were moderate to strong activities. Furthermore, the Minimum Inhibition Concentration (MIC) of secondary metabolites extract of SL1 against S. aureus ATCC6538 value was 250 ????g/mL while the values of MIC extract of SL4 against S. aureus ATCC6538 and E. coli ATCC8739 were 125 ????g/mL and 250 ????g/mL respectively and MIC extract of SL6 against E. coli ATCC8739 value was 125 ????g/mL. The secondary metabolites extract of SL1 isolate were alkaloid and tannin, SL4 were phenolic and alkaloid while SL6 isolate were alkaloid and terpenoid. Hence, endophytic fungi SL1 isolate was identified as Fusarium sp., SL4 as Dematophora sp., and SL6 isolate as Acremonium sp.

Heterogeneous Catalytic Conversion of Citronellal into Isopulegol and Menthol: Literature Review Amri Yahya; Dwiarso Rubiyanto; Is Fatimah
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The conversion of citronellal into isopulegol is a key route in the production of a number of important chemicals. In the perspective of green conversion, the use of a heterogeneous catalyst is superior due to its ease in separation and reusability, so it facilitates a highly economical conversion. In this review, we examine the use of some transition metals in cyclization reactions, which are suitable for citronellal conversion into isopulegol, and consider the potential progress in clay-based catalysts. The structure of clay which potentially provides the porosity by modification and supporting active metal is proposed to be the low-cost catalyst for the conversion. As other mechanism by porous materials-supported metal, the porosity of clay support contributes to conduct thesurface adsorption mechanism and the Broensted acid supply, meanwhile the metal acts as active site for cyclization, and in the one-pot conversion into menthol, as both cyclization and hydrogenation.

The Ability of Composite Ni/Al-carbon based Material Toward Readsorption of Iron(II) in Aqueous Solution Normah Normah; Neza Rahayu Palapa; Tarmizi Taher; Risfidian Mohadi; Hasja Paluta Utami; Aldes Lesbani
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

In this research, NiAl-LDH was synthesized using the coprecipitation method and modified with biochar and graphite to produce NiAlbiochar and NiAl-graphite composite materials. The adsorbent that has been synthesized is used for the application of adsorption of Fe(II) ions in aqueous solution. The resulting material was characterized by XRD (X-ray Diffraction) analysis, spectrophotometer FT-IR, BET analysis for determine the specific surface area and TG-DTA analysis. XRD diffractogram showed that the NiAl-Biochar and NiAl-graphite composite material had the diffraction pattern characteristic of the precursor. LDH that has been modified will have a larger surface area than the precursor. The surface area of NiAl-biochar reaches 438.942 m2/g and the surface area of NiAl-graphitereaches 21.595 m2/g. This composite material supports adsorbents with a large adsorption capacity to adsorb metals. Adsorption of Fe (II) using NiAl-Biochar and NiAl-graphite was stable for five regeneration cycles (<75.30%). The Fe(II) ion adsorption process tends to follow the Langmuir isotherm model which has a maximum capacity value (Qmax) of NiAl-Biochar composite material reaching 20 times with a value of 243.902 mg/g and the NiAl-graphite composite reaching 72.464 mg/g, so that the carbon-based composite material is considered effective. adsorbent to remove Fe(II) ion and can increase the stability of the structure for adsorption regeneration. The results of the analysis of thermodynamic parameters showed that the adsorption process was endothermic, tookplace spontaneously and the solid-liquid phase interface increased according to the increasing degree of disorder.

The Capability of Biochar-Based CaAl and MgAl Composite Materials as Adsorbent for Removal Cr(VI) in Aqueous Solution Novie Juleanti; Neza Rahyu Palapa; Tarmizi Taher; Nurlisa Hidayati; Bunga Indah Putri; Aldes Lesbani
Science and Technology Indonesia Vol. 6 No. 3 (2021): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The development of layered double hydroxide materials into composites with carbon-based materials in the form of CaAl-Biochar and MgAl-Biochar has been successfully carried out. The success parameters of the preparation process include XRD, FT-IR, Adsorption-Desorption N2, SEM, and TG-DTA. The success through XRD is evidenced by the appearance of the typical diffraction peaks of double-layer hydroxy around 2???? = 11°(003), 20°(006), and 60°(113). In addition, there is diffraction around 22°(002) which is the typical diffraction of biochar. FT-IR analysis showed successful preparation in the presence of functional groups around 1381cm−1 which indicated nitrate vibrations from double-layer hydroxy. Another spectrum that also appears on 1103 cm−1 is a characteristic of biochar (???? Si-O-Si). Adsorption-Desorption N2 analysis showed that the surface area data of 2 −1 2 −1 CaAl-Biochar was greater than MgAl-Biochar, which were 150.987 m .g and 111,404 m .g , respectively. The adsorption capacity of CaAl-Biochar reached 588.235 mg.g−1 and 426.316 mg.g−1 for MgAl-Biochar. The adsorbent materials of CaAl, MgAl, Biochar, CaAl-Biochar, and MgAl-Biochar tend to follow the Langmuir isotherm model with adsorption processes that tend to be spontaneous. The results of regeneration of the composite material lasted up to 5 cycles. The first cycle of CaAl-Biochar reached 96.647% to 82.666% in the last cycle, while MgAl-Biochar reached 90.885% in the first cycle to 73.454% in the last cycle.

Page 1 of 2 | Total Record : 13

1 2

Filter by Year

2021 2021

Filter By Issues

All Issue Vol. 11 No. 1 (2026): January Vol. 10 No. 4 (2025): October Vol. 10 No. 3 (2025): July Vol. 10 No. 2 (2025): April Vol. 10 No. 1 (2025): January Vol. 9 No. 4 (2024): October Vol. 9 No. 3 (2024): July Vol. 9 No. 2 (2024): April Vol. 9 No. 1 (2024): January Vol. 8 No. 4 (2023): October Vol. 8 No. 3 (2023): July Vol. 8 No. 2 (2023): April Vol. 8 No. 1 (2023): January Vol. 7 No. 4 (2022): October Vol. 7 No. 3 (2022): July Vol. 7 No. 2 (2022): April Vol. 7 No. 1 (2022): January Vol. 6 No. 2 (2021): April 2021 Vol. 6 No. 4 (2021): October Vol. 6 No. 3 (2021): July Vol. 6 No. 1 (2021): January Vol. 5 No. 4 (2020): October Vol. 5 No. 3 (2020): July Vol. 5 No. 2 (2020): April Vol. 5 No. 1 (2020): January Vol. 4 No. 4 (2019): October Vol 4 No 3 (2019): July Vol. 4 No. 2 (2019): April Vol 4 No 2 (2019): April Vol. 4 No. 1 (2019): January Vol. 3 No. 4 (2018): October Vol. 3 No. 3 (2018): July Vol. 3 No. 2 (2018): April Vol. 3 No. 1 (2018): January Vol. 2 No. 4 (2017): October Vol. 2 No. 3 (2017): July Vol. 2 No. 2 (2017): April Vol. 2 No. 1 (2017): January Vol. 1 No. 1 (2016): October More Issue

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name
-

Contact Email
-

Phone
-

Journal Mail Official
-

Editorial Address
-

Location
Kab. ogan ilir,

Sumatera selatan

INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name -

Contact Email -

Phone -

Journal Mail Official -

Editorial Address -

Location Kab. ogan ilir, Sumatera selatan INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Contact Name
-

Contact Email
-

Phone
-

Journal Mail Official
-

Editorial Address
-

Location
Kab. ogan ilir,

Sumatera selatan

INDONESIA