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Sainteknol : Jurnal Sains dan Teknologi
Published by Universitas Negeri Semarang
ISSN : 02164566     EISSN : 25273604     DOI : http://dx.doi.org/10.15294/sainteknol
Core Subject : Science,
Computer Science & IT
Sainteknol published a scientific paper on the results of research and studies in the field of science and technology. Published biannually in June and December contained the writings lifted from the results of research and critical-analysis study in science and technology.
Arjuna Subject : Umum - Umum
Articles 560 Documents
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Study of Heavy Metal Content in Lola Snail (Trochus niloticus) in The Karang Island of Central Tapanuli Regency
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 1 (2023): June 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i1.43387

Abstract

Research on the analysis of heavy metal content in the waters of Karang Island, Central Tapanuli Regency aims to know the metal content in Lola Snail meat, sediment, and Lola Snail shells. The research method begins with taking samples of Lola snails and sediments on Karang Island and preparing the samples. Then, the samples were analyzed by AAS (Atomic Absorption Spectrometry) to determine the content of heavy metal elements in the meat of Lola Snail, followed by XRD (X-Ray Diffraction) testing to determine the content of heavy metal elements in sediments, and also testing with EDX (Energy Dispersive X-Ray) to determine the content of heavy metals in the shell. The results of the analysis on the AAS test showed that the order of heavy metal concentrations in Lola snail meat at station I was Zn Cr Cu Cd Pb, while at station II was Zn Cu Cr Cd Pb. The results of the sequence of heavy metal concentrations using XRD in sediments around Karang Island at the station I was Zn Cr Cu Cd Pb, while at station II was Zn Cd Cu Cr Pb. The results of the analysis on the shells of Lola snails using EDX at both stations showed they did not contain heavy metal elements (Pb, Cd, Cu, Cr, and Zn), but only contained O, Ca, Mg, Na, Al, and Si elements.
The Potential of Earthworms (Eudrilus eugeniae) in Vermicompost Production from Vegetable Market of Waste Cabbage and Fruit Skins
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 1 (2023): June 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i1.43485

Abstract

Traditional markets are one of the highest contributors to waste. Traditional markets can produce a lot of waste, one of the wastes with a large amount is organic waste. The alternative that can be done to deal with organic waste and can be converted into a product is to make compost using the vermicompost method. The aim of this study was to find out the length of time for composting in the manufacture of compost, to determine the optimal amount of Eudrilus eugeniae in the composting process, and to find out the optimal distribution of waste in composting. The incubation process for compost was carried out for 8 weeks, with sampling at weeks 4, 6, and 8. Sampling was carried out to analyze the macronutrient content consisting of C-Organic, nitrogen, and potassium. Content analysis was carried out using UV/VIS spectrophotometry for analysis of C-Organic content, Kjeldahl method for nitrogen content analysis, and Atomic Absorption Spectrophotometer (AAS) for potassium content analysis. The specifications for compost from organic waste are based on the Indonesian National Standard (SNI 19-7030-2004). This research resulted in C-Organic content of 6.1-8.1%, nitrogen content of 0.32-0.43%, and potassium content of 0.16-0.23%.
Kinetic Modelling of Liquid-Solid Extraction of Bioactive Compounds from Ginger Waste using Subcritical Water
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 1 (2023): June 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i1.44589

Abstract

Kinetic modelling played a key role in the development of subcritical water extraction for bioactive compounds such as: shogaol and gingerol from ginger waste. Liquid-solid extraction kinetics could predict the extraction phenomenon and increase the efficacy of extraction process. The aim of this study was to develop a mathematical model of leaching kinetics and determine the rate constant of extraction process (k) of shogaol and gingerol in ginger pulp which is in the subcritical water phase. The research was carried out in two work stages, namely modeling and experimentation. The modeling was done by comparing three extraction kinetic models, namely pseudo first order, pseudo second order and the distribution coefficient. The model was postulated and validated with experimental data using Matlab. The subcritical water extraction process of shogaol and gingerol in ginger waste was occurred at 140 ℃ with a pressure of 3.5 bar. The extracts had been separated from raffinate and further analyzed using HPLC-MS. The results showed that the pseudo first order kinetic model described well the phenomenon of subcritical water extraction with regression values was 0.9882 for gingerol and 0.9682 for shogaol respectively. The rate constant of extraction process (k) for gingerol and shogaol were 0.1101  and 0.3130 , respectively. This showed that the shogaol extraction rate was higher than the gingerol extraction rate.
Production of Liquid Soap from Virgin Coconut Oil with the Active Ingredient Citronella Oil
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 1 (2023): June 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i1.44060

Abstract

The use of hand-washing soap is able to kill germs because it can remove oil and dirt that sticks to the hands. In making this liquid soap, active substances from nature, which is citronella oil, are used as anti-bacterial and anti-fungal agents. This study aims to study the factors that influence the response of free alkali and optimum conditions in the manufacture of liquid soap. The optimization method uses Response Surface Methodology (RSM) based on Central Composite Design. Experimental variables were carried out at reaction temperature (60-80°C), KOH concentration (30-50%), and reaction time (30-50 minutes). The results of the analysis using statistical software obtained the optimum operating conditions for the reaction time of 56,818 minutes, KOH concentration of 46,818%, and reaction temperature of 86,818°C with a free alkali value response of 0.04158%. These results meet the SNI 06-4085-1996 standard with a free alkali value below 0.1%.
Thermal Behavior and Kinetic of Degradation of PVA and PVA/CS/AL Blend
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 1 (2023): June 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i1.42675

Abstract

Studying thermal behavior, especially regarding the kinetics of the degradation of materials has attracted attention in this recent years because it can provide information about the stability of materials in various conditions and how the mechanism of material degradation. In this research, the thermal behavior and kinetics of thermal degradation of polyvinyl alcohol (PVA) and polyvinyl alcohol (PVA)/cassava starch (CS)/alkaline lignin (AL) with glycerol as a plasticizer were investigated and compared by the thermogravimetric analyzer. The test was carried out for samples under non-isothermal conditions in nitrogen at a single heating rate of 10 °C/min. The activation energies were calculated using Coats-Redfern, Broido, and Horowitz-Metzger methods. The results showed that PVA/0 and PVA/CS/AL had four decomposition steps with the main degradation of PVA/0 and PVA/CS/AL in the second and third decomposition steps. The first degradation of PVA/0 and PVA/CS/AL occurred at 125 °C - 270 °C with a decomposed mass of 35.94%, and 135 °C – 250 °C with a decomposed mass of 31.84%, respectively. The second degradation of PVA/0 and PVA/CS/AL was at  270 °C - 385 °C with a decomposed mass of 40.33%  and 250 °C – 395 °C with a decomposed mass of 38.62%. The values of activation energies using Coats-Redfern, Broido, and Horowitz Metger methods of PVA/0 were 57.08 KJ/mol, 64.82 KJ/mol, and 70.57 KJ/mol, respectively. The values of activation energies using Coats-Redfern, Broido, and Horowitz Metger methods of PVA/CS/AL were 74.49 KJ/mol, 82.17 KJ/mol, and 95.65 KJ/mol, respectively. The lower activation energy indicates that degradation reactions occur more easily. PVA/CS/AL has slightly better thermal stability than PVA/0.
Comparison of Ultrasonic Wave Pretreatment and Microwave-KOH Combination Pretreatment in Producing Bioethanol Using Rice Husk Waste Ardhiansyah, Hanif; Putri, Radenrara Dewi Artanti; Kusumaningrum, Maharani; Akbar, Faizal Reza Amirruddin; Fidiano, Daffa Bimo
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 2 (2023): December 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i2.50272

Abstract

Rice husk is a type of lignocellulosic biomass that can be chosen as a raw material for bioethanol production because it is abundant, cheap, and renewable. However, when it comes to lignocellulosic biomass, the main obstacle in using rice husks is the pretreatment process to remove the lignin content and prepare the lignocellulose so that it can be easily hydrolyzed. In this study, two combinations of pretreatment were used, namely microwave pretreatment and ultrasonic pretreatment, which used several variables. Microwave pretreatment uses variable time (2.5 minutes, 5 minutes, and 7.5 minutes) and power (100, 180 and 300 watts) as well as ultrasonic pretreatment uses variable time (20 minutes, 25 minutes, and 30 minutes) and power (70, 80 and 90 watts). The pretreatment results were hydrolyzed with sulfuric acid and fermented using saccharomyces cerevisiae yeast at varying times (3, 6, 9, 12, and 15 days). This research shows that microwave pretreatment is the most effective in reducing lignin. The lowest lignin content was 10.58% after 5 minutes and 180 watts of power. Bioethanol levels increased until the 15th day of fermentation, with the highest yield of 16%.
Analysis of Voids and Porosity and Its Influence on The Quality of Syntactic Foam Composites Munawar, Maulana Dzaki; Hakim, Moh Luqman; Wijaya, Ade Mundari; Novriadi, Dwi
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 2 (2023): December 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i2.49530

Abstract

The syntactic foam composite possesses both light and strong qualities. Syntactic foam composite is commonly employed as a buoyant lighting material in amphibious aircraft due to its excellent foaming capability. Composite syntactic foam is utilized because of its ability to efficiently support material drying while maintaining excellent structural strength (mechanical characteristics). In order to ascertain the syntactic compound density, one can determine the composite density based on the ASTM D790 standard. This involves evaluating the porosity calculation and doing a literature review to establish the characteristics of the void. The density of a syntactic foam composite is determined by the density of the filling matrix (microballoon k15), the percentage of porosity, and the identification of voids. The use of the K15 microballoon material will reduce the overall density of the composite because of its substantial structure. The number of small cavities within the composite syntactic foam is indicated by the porosity ratio.Nevertheless, not all apertures present in syntactic foam composites can be classified as k15 microballoon structures, as the composite manufacturing process may result in the formation of air bubbles that become trapped within the composite. The function has no return value. The excessive presence of voids can significantly reduce the density and mechanical strength, leading to a drop in the overall quality of the syntactic foam composite. Porosity analysis is crucial for assessing the quality of drying in syntactic foam composites. The study involved assessing the composite density of syntactic foam with varying concentrations of 0-50% w/w of the k15 microballoon material, following the ASTM D790 standard. The porosity value of the foam was subsequently determined and studied. The findings of this study can serve as a robust point of reference for analyzing the correlation between the density of the reference material and the composite syntactical foam's relative density in different variations.
Utilization of Nutgrass (Cyperus Rotundus L.) as a Phytoremediator in Reducing BOD and COD Levels of Batik Liquid Waste Using Constructed Wetlands in Sub-Surface Flow Type Irsyada, Muhamad Zakky; Fauziyyah, Hasna Amalia; Sari, Ayuk Permata
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 2 (2023): December 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i2.49818

Abstract

The process of dyeing batik fabric is a significant source of water pollution due to synthetic dyes. Only 5% of this compound is used, while 95% will be disposed of as waste. This compound is relatively stable, so it is tough to degrade in nature and is dangerous for the environment because it can cause effects such as increasing COD (Chemical Oxygen Demand) and BOD (Biological Oxygen Demand). Constructed wetlands in sub-surface flow type is a wastewater treatment method that utilizes the role of plants and microorganisms found in the plant root area or rhizosphere. Nutgrass (Cyperus Rotundus L.) is rarely used and is considered a weed that causes harm to surrounding plants. On the other hand, nutgrass is a plant with good remediation and straightforward maintenance. In this research, the nutgrass plant was used as a phytoremediator with planting media in the form of sand and gravel to improve the performance of constructed wetlands in processing liquid batik waste. Based on the analysis of BOD and COD test parameters, the results showed that nutgrass could reduce BOD levels by up to 75% and COD levels by 73% so that wastewater produced from artificial wetlands flows more safely and can be used for irrigation and plants sanitation.
Encapsulation of Walnut Oil in Urea-Formaldehyde for Self-Healing Coating: Effect of Mixing Speed Suyatmo, Reviana Inda Dwi; Topandi, Abdussalam; Gultom, Indah Gita Cahyani; Nulhakim, Lukman
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 2 (2023): December 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i2.48141

Abstract

Self-healing coating is a technology where repairation of a coating can be done automatically. The self-healing agent is encapsulated in the form of microcapsules. When the microcapsules or shell material breaks, the healing agent released onto the damaged surface. In this study, walnut oil was used as a healing agent because it belongs to the drying oil which has been widely used as a coating. The polymer used as the microcapsule shell is urea-formaldehyde. This research was conducted to examine the effect of mixing speed on the diameter and thermal stability of microcapsules encapsulated by walnut oil in urea formaldehyde, as well as to see the self-healing performance. The results of FTIR testing proved that the microcapsules consist of Poly Urea Formaldehyde (PUF) as a shell material. The research showed that the mixing speed of 860 rpm produced microcapsules with the smallest diameter of 90.1426 micrometer and the highest decomposition temperature of 362.38°C. The results of self-healing tests on steel plates prove that the healing agent used has succeeded in repairing the damage by covering the surface of the scratched sample.
Analysis of Total Phenolic and Flavonoid Levels in Carrot (Daucus carota L.) Extract with Different Solvents Polarity Afrellia, Rika Eka; Puspitasari, Anita Dwi
Sainteknol : Jurnal Sains dan Teknologi Vol 21, No 2 (2023): December 2023
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v21i2.47248

Abstract

Carrot (Daucus carota L.) contains phenolic and flavonoid compounds that contribute to various pharmacological activities. Phenolic and flavonoids can be extracted using various solvents. Solvent polarity difference will produce amounts and types of secondary metabolites differently. This research aims to compare the total phenolic and flavonoid content of carrot extract from various solvents. Carrot was extracted using the maceration method with n-hexane, ethyl acetate, and 70% ethanol as solvent to obtain n-hexane, ethyl acetate, and 70% ethanol extract of carrot. Spectrophotometry carried out the determination of total phenolic content by comparing gallic acid and total flavonoids with a comparison of quercetin. The maximum wavelength of gallic acid is 739.60 nm and the operating time of 120 minutes. The maximum wavelength of quercetin is 427.50 nm and an operating time of 30 minutes. Total phenolic and flavonoid levels of carrot extract from the three solvents were analyzed statistically through one-way ANOVA followed by the Bonferroni test at a 95% confidence level. The results showed that the total phenolic contents of the n-hexane extract, ethyl acetate, and 70% ethanol extract of carrot 11.881±0.31; 24.308±1.33 and 39.398±1.65 mg GAE/g extract. The flavonoid content was 2.650±0.13; 20.675±2.58 and 9.063±0.99 mg QE/g extract respectively. The highest total phenolic content was obtained from 70% ethanol solvent and the highest total flavonoid was obtained from ethyl acetate solvent.

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