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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 26 Documents
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Search results for , issue "Vol. 9 No. 3 (2024): July" : 26 Documents clear
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.
Removal of Methyl Orange in Aqueous Medium using ZnO/Bentonite as Semiconductor by Photocatalytic Process Priatna, Satria Jaya; Yuliana, Ayu; Zulkarnain; Melwita, Elda; Arsyad, Fitri Suryani; Mohadi, Risfidian
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.2024.9.3.539-545

Abstract

Pillarization of bentonites (from East Java) with ZnO semiconductors has been synthesized using co-precipitation methods into a ZnO/Bentonite composite and applied as a catalyst in a photocatalytic process to remove Methyl Orange (MO) dyes. The optimum pH condition of MO dyes is at pH 2 with a degradation rate of 22.91% (from 15 mg/L to 11.523 mg/L). The optimum ZnO/Bentonite catalyst weight condition is 200 mg, with a degradation rate of 29.11% (from 15 mg/L to 10.596 mg/L). The optimum time condition for UV lamp irradiation is 60 minutes, with a degradation rate of 64.92% (from 15 mg/L to 5.244 mg/L). The kinetics of MO photocatalytic reaction using ZnO/Bentonite catalyst follows the pseudo-first-order Langmuir Hinshelwood-Santosa kinetic model with photocatalytic reaction rate constant (k1) of 0.014 and photocatalytic equilibrium constant (K) of 0.012.
Activity of Mangrove-Derived Fusarium equiseti 20CB07RF Extract Against Clinical, Antibacterial-Resistant Pseudomonas aeruginosa Bahri, Syaiful; Setiawan, Wawan Abdullah; Setiawan, Fendi; Lutfiah, Rosyidatul; Juliasih, Ni Luh Gede Ratna; Ambarwati, Yuli; Ahmadi, Peni; Arai, Masayoshi; Hendri, John; Hadi, Sutopo; Setiawan, Andi
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.2024.9.3.594-604

Abstract

Endophytic fungi originating from mangroves are potential sources of secondary metabolites with varying bioactivities. This research explores the bioactive metabolites produced by endophytes derived from mangrove plants. Endophytic fungi were collected from various parts of several mangrove plants (roots, stems, and leaves, as well as the surrounding mud). A total of 17 endophytics fungi were obtained. The isolates were derived from the leaves (1 isolate), stems (8 isolates), roots (5 isolates), and surrounding mud (3 isolates). A single fungal colony was cultured using solid-state fermentation for 14 days. The fermented fungal biomass was extracted using ethyl acetate (EtOAc) and evaluated for its antibacterial activity against clinical pathogenic bacteria. In the preliminary screening, the EtOAc extract of the CB07RF1 isolate exhibited notable growth-inhibitory effects against Pseudomonas aeruginosa. The isolate was verified by molecular identification using a study of the rDNA internal transcribed spacer (ITS) sequence, revealed that isolate CB07RF1 was very similar to Fusarium equiseti (99% similarity). Isolate 20CB07RF1, obtained by solid-state fermentation using a rice medium indicated as peptide compound group, and featured active components that exhibited potent growth inhibitory activity against Pseudomonas aeruginosa at a concentration of 12.5 mg/mL. This study demonstrates, for the first time, that Fusarium equiseti extracts grown in a rice medium contain antimicrobial compounds that can inhibit the growth of P. aeruginosa, an important clinical pathogen known for its antibacterial resistance. These findings accent mangrove endophytic fungi as important sources of bioactive compounds and will advance related research in the fields of biotechnology, pharmacology, and life sciences.
Nickel Salt Dependency as Catalyst in the Plating Bath on the Film Properties of Cu/Cu-Ni Rosyidan, Cahaya; Kurniawan, Budhy; Soegijono, Bambang; Maulani, Mustamina; Samura, Lisa; Nababan, Frederik Gresia; Putra, Valentinus Galih Vidia; Susetyo, Ferry Budhi
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.2024.9.3.529-538

Abstract

Metal plating frequently employs nickel (Ni) and copper (Cu) as anodes. Cu/ Cu-Ni film formed has many advantages, such as better corrosion resistance and high hardness characteristics. This study aims to assess the properties of Cu/Cu-Ni film, such as phase, surface morphology, crystallographic orientation, hardness, corrosion analysis, and contact angle, which were fabricated using electrodeposition with various Ni salt additions (0.3, 0.5 and 0.7 M). In addition, the cathode current efficiency (CCE) and deposition rate of the Cu/Cu-Ni electrodeposition were also investigated. An increase in Ni salt in the plating bath could enhance the pH, promoting higher CCE and depleting hydrogen evolution at the cathode, leading to the presenting Ni phase in the alloy. The higher concentration of Ni salt in the solution could also enhance the deposition rate due to a shift to a pH value, which affects the roughening of the surface morphology, promoting a higher contact angle. All crystal structures generated by Cu/Cu-Ni electrodeposition were FCC, with the preferred orientation of the (111) plane. Crystallite size and lattice strain depend on the deposition rate. Less crystallite size and lattice strain affect the film’s hardness and corrosion resistance. Moreover, the third bath had the resulting Cu-Ni layer with the best hardness and corrosion rate of around 136 HV and 0.081 mmpy.
The Production of Renewable Fuels Sago Dregs and Low-Density Polyethylene by Pyrolysis and its Characterization Jahiding, M; Mashuni, Mashuni; Handayani Hamid, Fitri; Sitti Ilmawati, Wa Ode; Hamdana, Renaldi
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.2024.9.3.565-576

Abstract

Biomass has been suggested as a sustainable alternative to substitute fossil fuels. Based on the pyrolysis method, the biomass would be converted into energy through decomposition by thermal degradation under an inert atmosphere, resulting in charcoal, liquid, and gas products. The quality of oils is effectively enhanced through the pyrolysis of lignocellulosic biomass and plastic due to the facilitation of deoxygenation by plastics. This study investigates the impact of incorporating low-density polyethylene (LDPE) plastic in co-pyrolysis with sago dregs (SDs) waste. Pyrolysis of SDs and LDPE mixtures with ratios of 5:1, 4:2, 3:3, 2:4, and 1:5 at various temperatures of 375°C, 425°C, and 475°C. The maximum oil yield obtained for SDs and LDPE pyrolysis was 44.94%. The calorific value (CV) of all observed compositions is a minimum of 10,579.57 kcal kg-1 and a maximum of 11,545.21 kcal kg-1. The gas chromatography-mass spectroscopy (GC-MS) analysis confirmed the interaction between SDs and LDPE on co-pyrolysis. The addition of LDPE will produce rich aliphatic and aromatic compounds, like the proportions of alkanes (45.53%), alkenes (30.62%), alcohol (0.4%), and benzene (17.68%). Co-pyrolysis of SDs and LDPE promotes enhanced oil production by reducing oxygenated compounds and increasing hydrocarbon compounds.
Synthesis and Characterization of Perovskite Manganate Based on La0.7Ca0.3MnO3 with Ni and Ti doping as Microwave Absorber Material Saptari, Sitti Ahmiatri; Mar’ah, Mufidatul; Taryana, Yana; Sudrajat, Nanang
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.2024.9.3.577-585

Abstract

Research has been carried out on the effect of Ni and Ti doping on the microwave absorption properties of the perovskite manganate material La0.7Ca0.3Mn1-xNix/2Tix/2O3 (LCMNTO) with variations x = 0; 0.03; 0.05; and 0.1, which were synthesized by the sol-gel method. The effect of Ni and Ti doping on the structure, grain size, magnetic properties, and microwave absorption properties were investigated in detail by various analytical methods. XRD (x-ray diffraction) characterization showed that the material La0.7Ca0.3Mn1-xNix/2Tix/2O3 has a single phase with an orthorhombic crystal system. The SEM (scanning electron microscope) results showed a tendency to decrease in grain size when the composition of Ni and Ti dopants began to increase. VSM (vibrating sample magnetometer) characterization shows that La0.7Ca0.3Mn1-xNix/2Tix/2O3 is a soft magnet with magnetic properties that decrease with increasing Ni and Ti dopant composition. The characterization of VNA (vector network analyzer) in the 8-12 GHz shows that the highest ability to absorb microwaves is 98% at 8.24 GHz, and there is an addition of absorption areas point and widening of the absorption bandwidth. Thus, the material La0.7Ca0.3Mn1-xNix/2Tix/2O3 has the potential to become a microwave absorber material.
The Influence of Catalyst Loading on Electrocatalytic Activity and Hydrogen Production in PEM Water Electrolysis Rohendi, Dedi; Amelia, Icha; Sya'baniah, Nyimas Febrika; Yulianti, Dwi Hawa; Syarif, Nirwan; Rachmat, Addy; Fatmawati; Majlan, Edy Herianto
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.2024.9.3.556-564

Abstract

The climate change caused by the widespread and continuous use of fossil fuels is a problem that needs to be addressed urgently. One of the solutions offered is through an energy transition towards the use of new or renewable and low-carbon fuels. Hydrogen gas as a carrier of energy is an alternative solution that has attracted the attention of researchers, due to its high combustion energy and environmental friendliness. The production of hydrogen gas using the Proton Exchange Membrane Water Electrolysis (PEMWE) method is considered effective for large-scale production. This study investigates the impact of catalyst loading and various current densities on hydrogen production in the PEM water electrolysis process, utilizing the Cu2O/C catalyst. This study investigates the impact of catalyst loading and different current densities on hydrogen production in the PEM water electrolysis process, utilizing the Cu2O/C catalyst. The electrode catalytic properties were evaluated using the Cyclic Voltammetry (CV) method to determine the Electrochemical Surface Area (ECSA) and the Electrochemical Impedance Spectroscopy (EIS) method to determine the electrical conductivity. The ECSA and EIS measurements demonstrated that the best results were obtained at a higher catalyst loading of 2 mg/cm2 with an ECSA value of 0.21 m2/g and electrical conductivity of 3.04 × 10−6 S/cm. The production of hydrogen results showed that the highest hydrogen production rate was 3.75 mL/s with a catalyst loading of 2.5 mg/cm2, indicating that increasing the load could lead to a higher rate of hydrogen gas production, but this is highly dependent on the surface area utilized. Additionally, at higher current densities, the cell resistance in the electrolysis process may decrease, leading to reduced electrode efficiency for hydrogen production. Thus, the use of high currents may not always be advantageous in hydrogen production using the PEM water electrolysis method.
New Encapsulation of Fucoxanthin Isolated from Cyclotella striata by Nano Chitosan–Pectin using Ionic Gelation Method Nahrowi, Ridho; Solehati, Siti; Widyastuti, Widyastuti; Juliasih, Ni Luh Gede Ratna; Pandiangan, Kamisah Delilawati; Setiawan, Andi; Hendri, John
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.2024.9.3.517-528

Abstract

Fucoxanthin is an anticancer, antioxidant, antimicrobial, and anti-inflammatory bioactive compound. Unfortunately, the conjugated double bonds of the fucoxanthin structure make it unstable, posing issues for product development, particularly with regard to shelf life. This research study aims to synthesize nano chitosan–pectin and encapsulate isolated fucoxanthin by nano chitosan–pectin using an ionic gelation method. Fucoxanthin was obtained through isolation of microalgae species Cyclotella striata. The best result of nanoparticle size using a particle size analyzer was chitosan:pectin 1 : 2 of 172 nm. Fourier transform infrared analysis showed that there was an interaction between chitosan–pectin and fucoxanthin, which was characterized by a shift in the C O absorption fucoxanthin from 1736 to 1632 cm-1. The result of morphological analysis of nano chitosan–pectin–fucoxanthin using a scanning electron microscopeshows a spherical morphology with a size between 140 and 265 nm. The result of encapsulation efficiency was 75.18%, whereas encapsulation stability increased fucoxanthin oxidation half-life 4.7 times longer than that of unencapsulated fucoxanthin. The nano chitosan pectin could be utilized as a matrix conjugate to increase the stability of fucoxanthin significantly by encapsulation. This information is expected to be useful in developing encapsulation applications for unstable compounds.
Application of KBaYSi2O7:Bi3+,Eu3+ Phosphor for White Light-Emitting Diodes with Excellent Color Quality Loan, Nguyen Thi Phuong; Thuy, Le Xuan; Thai, Nguyen Le; Lee, Hsiao Yi; Cong, Pham Hong
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.2024.9.3.756-765

Abstract

This paper examines the properties of two phosphor materials synthesized via utilizing the sol gel method: KBaYSi2O7:Bi3+ (KBYS:Bi) phosphor providing cyan/deep-blue emission and KBaYSi2O7:Bi3+,Eu3+ (KBYS:Bi,Eu) phosphor exhibiting tunable emission from near-UV to red. The optimal doping concentrations for Bi3+ and Eu3+ are 0.2% and 3.5%, respectively. It is found that the ability to give discrepant emission peaks under different excitation sources of the KBYS:Bi phosphor is attributed to the occupancy of Bi3+ in different cation hosts. Meanwhile, co doping the Eu3+ and Bi3+ into the KBYS host leads to red and cyan emission regions, enabling the emission tunability of the KBYS:Bi,Eu phosphor. KBYS:Bi,Eu phosphor was then used in combination with YAG:Ce3+ and blue chips to fabricate a white light emitting diode (LED) model. The particle sizes of KBYS:Bi,Eu phosphor are adjusted to examine its influences on the LED properties. With increasing particle sizes (≥12 µm), the KBYS:Bi,Eu phosphor can improve the scatter efficacy, transmission power, lumen output, and color performance (rendition and uniformity). Both KBYS:Bi and KBYS:Bi,Eu phosphors are promising luminescent phosphors that can be combined with other phosphor with different emission colors to obtain the full-spectrum or tunable white light for LEDs.
Modification Structure of Cinnamaldehyde with Primary Amines by Reflux and Sonication Methods in the Presence of Sulfuric Acid as a Catalyst Setyono, Hilda Alfiyani; Suryanti, Venty; Putri, Alfianita Utama; Koketsu, Mamoru
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.2024.9.3.586-593

Abstract

Cinnamon is one of the most valuable natural resources that sustains life and exists freely in nature. Cinnamaldehyde is the primary compound in cinnamon oil. It has a unique structure that contains a benzene ring, an aldehyde group, and an unsaturated double bond. Cinnamaldehyde has been structurally modified to improve biological activity. In this research, cinnamaldehyde and nitrophenyl amines were reacted with sulfuric acid as a catalyst by refluxing and sonication. UV-Vis Spectroscopy, FT-IR, 1H-NMR, and 13C-NMR were used to validate the chemical structures. Thin-layer chromatography (TLC) revealed a new single spot formed by the reaction of cinnamaldehyde and 4-amino-2-nitrophenol. By refluxing for 2 hours or sonicating for 30 minutes, a novel imine chemical, 4-nitro-2-((3-phenylallylidene)amino)phenol, was effectively synthesized with a yield of 75.21% or 83.71%, respectively. This imine was obtained as a dark red powder with a melting point of 237 °C. Meanwhile, only sonication produced a novel product from the reaction of cinnamaldehyde and 4-nitroaniline. However, the structural elucidation has not yet been performed because the yield was so low. Surprisingly, there was no reaction between cinnamaldehyde and 2,4-dinitroaniline. It was most likely owing to the amine’s bulky structure and the presence of two nitro groups in the amine as electron-withdrawing groups that reduced the nucleophilicity of the amine. We demonstrated that sonication is a suitable approach for imine synthesis, as it is commonly utilized in organic compound synthesis protocols.

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