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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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A Study of the Magnetic Properties and Structure of Heusler Alloys Prepared by Arc-Melting Technique Khalefa, N. A.
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.2024.9.1.36-42

Abstract

Heusler alloys were prepared in this study using the Arc-Melting method in which 30 g of the Arc-melting pure elements were combusted in an Argon arc furnace. Saturation magnetization, X-ray diffraction (XRD) analysis, and scanning electron microscope (SEM) were used to characterize the prepared alloys in terms of the compositions (Co2TiZ), where Z= Al, Ge, Sb are related IVB sub-group metals. In this work, the specimens containing Ge and Ti have fully Ferro magnetically order and L21 chemical structure with magnetism due to the magnetic moments attributed to the Co site. The Heusler alloys containing IIB or IVB sub-group metals such as Al, Ti, or Ge behave ferromagnetism, with the magnetic moments being attributed to the magnetic moments of the Co sites. Heusler alloys containing the group IVB element such as Sb exhibited vacant chemical effects with Co sites, and they also contain some paramagnetic compounds. Heusler alloys with Sb element exhibited paramagnetic behavior with vacant chemical order. Alloys demonstrate different magnetic properties as a result of temperature change and exchange interaction with atomic structure.
Optimization and Characterization of Liquid Smoke Produced by Terminalia catappa Wood Pyrolysis and its In Vitro Antifungal Activity Oramahi, Hasan Ashari; Maurisa, Tirsa; Nurhaida; Darwati, Herlina; Rifanjani, Slamet
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.2024.9.1.207-214

Abstract

This research utilized response surface methodology (RSM) to explore how the yield of liquid smoke obtained from ketapang wood (Terminalia catappa) is influenced by the size of wood particles and the temperature of pyrolysis. Gas chromatography-mass spectrometry (GC-MS) was used to characterize the liquid smoke. To assess liquid smoke’s antifungal effects, a petri dish bioassay was conducted using 1.0-4.0% (v/v) concentrations against Schizophyllum commune. RSM was applied to optimize vinegar from T. catappa by varying the wood particle size and the pyrolysis temperature. The optimal yield, 24.67%, was obtained with a 3.22 mm particle size and a 425°C pyrolysis temperature. The liquid smoke produced at 400-450°C completely inhibited of S. commune growth at 2.0-4.0%. The primary components of the liquid smoke at 400°C were 2-methoxy- phenol (24.85%), creosol (8.39%), 4-ethyl-2-methoxy- phenol (7.21%), 2-5-methyl-furancarboxaldehyde (4.55%), and 4-ethyl-2-methoxy-phenol (3.74%). The primary components at 425°C were 2-methoxy-phenol (25.60%), creosol (15.15%), 5-methyl-2 furancarboxaldehyde (12.75%), and 2,6-dimethoxy-phenol (9.31%). At 450°C, the main components were 2-methoxy-phenol (25.26%), 4-ethyl-2-methoxy-phenol (8.46%), creosol (8.40%), 5-methyl-2-furancarboxaldehyde (4.02%), and 4-ethyl-2-methoxy-phenol (3.98%).
Generalized Hölder Inequality in Herz-Morrey Spaces with Variable Exponent Rahman, Hairur; Karim, Corina
Science and Technology Indonesia Vol. 9 No. 3 (2024): July
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.2024.9.3.637-641

Abstract

The paper investigates the conditions for the generalized Hölder’s inequality with a variable exponent in Herz-Morrey spaces. The main results are based on the exponent functions p(·) and α(·) . The proof of the first main result using the generalized Hölder’s inequality in Lebesgue spaces. The second main result of the paper is related to the weak space of the generalized Hölder’s inequality with a variable exponent in Herz-Morrey spaces. The theorems state the equivalence of certain conditions for the inequality. Mathematical proofs and analysis are providing to support the presented results for findings contribute to the understanding of Hölder’s inequalities in variable exponent spaces and their applications in Herz-Morrey spaces.
Preissmann Four-Point Methods for Solution of Simplified Saint-Venant Equations Applied to Flood Routing in Prismatic Open Channels Bambang Agus Sulistyono; Widodo, Suryo
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.2024.9.1.183-188

Abstract

This research goal to compare the flow properties in the rectangular and trapezoidal open channels by examining the influence of the channel side slope is depicted by simplified Saint Venant Equations. The solution of these equations has been completed numerically by using Preissmann four-point scheme. The model is simulated using the Matlab application to point out the flow properties. The proposed model is validated by the model without simplification which was selected from the literature. The validation outcomes indicate that in common, the simulation outcomes of the two models have a good agreement. The simulation results show that the greater the slope of the channel side, the greater the peak discharge and the greater the time shift. The analysis emphasizes how channel geometry influences flow behavior, indicating that trapezoidal channels, with inclined side slopes z, yield slightly higher peak discharges compared to rectangular ones. For z = 0, discharge of peak Q = 7.38 m3/s and t = 18 s. For z = 2, discharge of peak Q = 7.39 m3/s and t = 21 s. For z = 4, discharge of peak Q = 7.45 m3/s and t = 23 s. For z = 6, discharge of peak Q = 7.51 m3/s and t = 24 s.
Results on Toeplitz Determinants for Subclasses of Analytic Functions Associated to q-Derivative Operator Nurali, Nurdiana Binti; Janteng, Aini
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.2024.9.2.354-358

Abstract

An analytic function, also known as a holomorphic function, is a complex-valued function that is differentiable at every point within a given domain. In other words, a function f (z) is analytic in a domain U if it has a derivative f′(z) at every point z in U. Let A represent the set of functions f that are analytic within the open unit disk D = {z ∈ ℂ : |z| < 1}. These functions possess a normalized Taylor-Maclaurin series expansion written in the form f (z) = z + Í∞ n=2 an z n where an ∈ ℂ, n = 2, 3, . . .. In recent years, the field of q-calculus has gained significant attention and research interest among mathematicians. The applications of this field are broadly applied in numerous subdivisions of physics and mathematics. In this research, we assume that S∗q and ℝq are subclasses of analytic functions obtained by applying the q-derivative operator. The objective of this paper is to obtain estimates for coefficient inequalities and Toeplitz determinants whose elements are the coefficients an for f ∈ S∗q and f ∈ Rq .
Kinetics of Homogeneous Reaction of Potassium Methoxide Based on K2CO3 Catalyst in Transesterification of RBDPO to Biodiesel Salam, Yosirham Abdu; Komariah, Leily Nurul; Hadiah, Fitri; Arita, Susila
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.2024.9.1.28-35

Abstract

Biodiesel production is generally catalyzed by potassium methylate or sodium methylate catalysts based on KOH and NaOH and these catalysts are still imported. The search for a cheap and effective catalyst continues to be carried out by researchers. One of the catalyst support materials currently in use involves impregnating K2CO3 with various substances, resulting in a heterogeneous catalyst. In this study, it was tried to use K2CO3 dissolved in methanol to produce a homogeneous potassium methylate catalyst. Potassium methylate-based homogeneous catalyst K2CO3-methanol is proven to have a very high function in the transesterification reaction of Refined Bleached Deodorized Palm Oil (RBDPO) into biodiesel, this is evidenced by the use of a catalyst percentage of 2% w and 30% w methanol to the weight of RBDPO resulting in an acid content in biodiesel of only 0.12% and a total glycerol of 0.124% in reaction time 3 hours, with the purity of the methyl ester in biodiesel reaching 98.80%. Meanwhile, for the calculation of homogeneous reaction kinetics, a reaction rate equation is produced where the order of the RBDPO transesterification reaction is order 2 (two) and the reaction rate constant is 0.0044.
Antioxidant and Antibacterial Activity of Endophytic Fungi Isolated from Fruit of Sungkai (Peronema canescens) Oktiansyah, Rian; Widjajanti, Hary; Setiawan, Arum; Elfita
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.2024.9.1.17-27

Abstract

Peronema canescens, often known as sungkai, is widely used and can be found all around Indonesia. The public believes that the leaves may reduce fever and strengthen the immune system. However, the effectiveness of sungkai fruit has not been thoroughly investigated. In this research, we looked at endophytic fungus extracts from sungkai fruit’s that have antioxidant and antibacterial properties. The study’s results will serve as the foundation for further investigation into the development of potential natural chemicals with antioxidant and antibacterial properties. Morphologically, the endophytic fungi isolated from sungkai fruit were identified. The antioxidant and antibacterial properties of endophytic fungal extracts were studied using the DPPH technique and the paper disk diffusion method. By employing molecular identification and column chromatography to separate the active compounds, the most likely endophytic fungal isolates were found based on the results of the bioactivity tests. Using 1D NMR spectroscopic methods, the chemical’s structure was determined, and the results were compared to NMR data for the same compound published in the literature. Fruit of sungkai had 8 strains of endophytic fungus (RBH1-RBH8). Strong antibacterial and very strong antioxidant activity were shown by the RBH5 isolate (IC50 < 20 μg/mL). Pythium periplocum was determined to be the RBH5 isolate based on molecular testing. Pure chemical compound extracted from RBH5 isolates shown highly potent and potent antibacterial and antioxidant effects. The chemical compound was identified by spectroscopy as 3-hydroxy-4(hydroxy(4-hydroxyphenyl)methyl)-γ-butyrolactone. The results of this study serve as the foundation for developing compounds as pharmaceutical raw materials via further research phases.
Tridiagonal Interval Matrix: Exploring New Perspectives and Application Thirupathi, Sivakumar; Thamaraiselvan, Nirmala
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.2024.9.1.77-85

Abstract

Tridiagonal interval matrices are relevant in diverse applications, especially in dealing with parameter estimation, optimization and circuit analysis uncertainties. This research paper aims to improve the computational efficiency of obtaining the inverse of a general tridiagonal interval matrix. This matrix is pivotal in electric circuit analysis. We achieve this by employing interval arithmetic operations in the LU decomposition process, enabling effective handling of circuit parameter uncertainties. This approach generates an inverse interval matrix that addresses uncertainties in circuit analyses.
Enhanced Efficiency for Biogas Production from Distillery Wastewater as Mixed with Molasses and Glycerol Waste in the Anaerobic Co-Digestion Rattanadilok Na Phuket, Kiattisak; Srimachai, Tussanee; Luanunkarb, Saowarod; O-Thong, Sompong
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.2024.9.1.120-128

Abstract

This experiment was conducted to decide the impact of molasses and glycerol waste on upgraded methane production in anaerobic co-digestion with distillery wastewater. Co substrates used for biogas production in the anaerobic co-fermentation process of distillery wastewater (DW) were molasses (ML) and glycerol waste (GW). The co-substrate concentration in all batch experiments varied between 1% and 5% (v/v). To study the efficiency of biogas production, the optimal ratio was chosen for operation in the PFR continuous reactor. Optimization results indicated that anaerobic co-digestion of DW with 5% GW and 1% ML could improve biogas quality and quantity. HRT for 30 days allowed R2 (95% DW: 5% GW) to produce maximum methane production per 11 m3 CH4/m3 mixed wastewater, followed by R1 (99% DW: 1%). ML) 6 m3 CH4/m3 mixed wastewater and control (100% DW) could only produce 2.7 m3 CH4/m3 mixed wastewater methane. As co-substrates, GW and ML can be balanced to coordinate the C/N ratio and pH of DW. In particular, the C/N ratio of the mixed sewage can be balanced, and the concentration of ammonia nitrogen within an anaerobic digestion tank can be diluted. Therefore, GW can be used as an optimal co-substrate as it improves the C/N ratio, dilutes toxic compounds within DW, and provides lower prices, thus increasing the potential for methanogenesis within DW affected to increase biogas production.
Synthesis and Characterization of ZnO/Cellulose Acetate Composite and its Activity as Antibacterial Agent Khefanny, Yemima Chellyne; Charlena; Sugiarti, Sri
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.2024.9.2.215-223

Abstract

Cellulose is an abundant natural polymer that can be applied in various fields. Cellulose has many types and derivatives, one of which is cellulose acetate. Cellulose can be obtained from various natural sources such as kepok banana peel. The a-cellulose content in kepok banana peel is high enough at 94% so that it can be utilized as a cellulose acetate raw material. Modification of cellulose acetate using antibacterial agents is needed, considering that cellulose does not have antibacterial properties. Metal oxide materials such as ZnO nanoparticles are used as antibacterial agents. This study added ZnO nanoparticles to cellulose acetate and tested its antibacterial activity. The characteristics of ZnO were analyzed by UV-Vis, PSA, and FTIR. The characteristics of cellulose acetate and composites were analyzed by FTIR and XRD. Antibacterial activity tests were performed on all samples. The results showed the band gap value of ZnO was 3.37 eV. The average size of ZnO nanoparticle distribution using PSA was 96.23 nm with an average PI value of 0.151. An indicator that the ZnO compound and cellulose acetate have been sucessfully mixed is the absorption band at wave number 488 cm−1. A composite crystal size of 24.14 nm and a crystallinity percentage of 34.05% were found using XRD data. S. aureus bacteria are more inhibited by all evaluated substances antibacterial properties than E. coli germs. ZnO/Cellulose Acetate composite is categorized as strong inhibition, while ZnO nanoparticles are categorized as medium inhibition.

Page 32 of 56 | Total Record : 551

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