cover
Article Per Year (5 Year)
All
Home Page
OAI Link
Editorial Team
Contact
Reviewer
Google Scholar
Contact Name
-
Contact Email
sainteknol_lp2m@mail.unnes.ac.id
Phone
-
Journal Mail Official
sainteknol_lp2m@mail.unnes.ac.id
Editorial Address
Research and Community Service Institute, Universitas Negeri Semarang, Sekaran, Gunungpati, Semarang, Central Java, Indonesia
Location
Kota semarang,
Jawa tengah
INDONESIA
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 555 Documents
 52   53   54   55   56 
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.

Page 56 of 56 | Total Record : 555

 52   53   54   55   56 

Filter by Year

2010 2023


Reset
Filter By Issues
All Issue Vol 21, No 1 (2023): June 2023 Vol 20, No 2 (2022): December 2022 Vol 20, No 1 (2022): June 2022 Vol 19, No 2 (2021): December 2021 Vol 19, No 1 (2021): June 2021 Vol 18, No 2 (2020): December 2020 Vol 18, No 1 (2020): June 2020 Vol 18, No 2 (2020): Desember Vol 18, No 1 (2020): Juni Vol 16, No 1 (2018): Juni No 1, 2018 Vol 16, No 2 (2018): December 2018 Vol 16, No 2 (2018): Desember 2018 Vol 16, No 1 (2018): June 2018 Vol 15, No 2 (2017): Desember 2017 Vol 15, No 2 (2017): December 2017 Vol 15, No 1 (2017): Juni 2017 Vol 15, No 1 (2017): June 2017 Vol 14, No 2 (2016): December 2016 Vol 14, No 2 (2016): December 2016 Vol 14, No 1 (2016): June 2016 Vol 14, No 1 (2016): June 2016 Vol 13, No 2 (2015): December 2015 Vol 13, No 2 (2015): December 2015 Vol 13, No 1 (2015): June 2015 Vol 13, No 1 (2015): June 2015 Vol 12, No 2 (2014): December 2014 Vol 12, No 2 (2014): December 2014 Vol 12, No 1 (2014): June 2014 Vol 12, No 1 (2014): June 2014 Vol 11, No 2 (2013): December 2013 Vol 11, No 2 (2013): December 2013 Vol 11, No 1 (2013): June 2013 Vol 11, No 1 (2013): June 2013 Vol 10, No 2 (2012): December 2012 Vol 10, No 2 (2012): December 2012 Vol 10, No 1 (2012): June 2012 Vol 10, No 1 (2012): June 2012 Vol 9, No 2 (2011): December 2011 Vol 9, No 2 (2011): December 2011 Vol 9, No 1 (2011): June 2011 Vol 9, No 1 (2011): June 2011 Vol 8, No 2 (2010): December 2010 Vol 8, No 2 (2010): December 2010 Vol 8, No 1 (2010): June 2010 Vol 8, No 1 (2010): June 2010 More Issue