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Eksakta : Berkala Ilmiah Bidang MIPA
Published by Universitas Negeri Padang
ISSN : -     EISSN : 25497464     DOI : https://doi.org/10.24036/eksakta/
Core Subject : Science, Education, Agriculture, Social, Engineering,
Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Energy Engineering Environmental Science Materials Science & Nanotechnology Mathematics Mechanical Engineering
Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) is an open access journal and peer-reviewed that publishes either original article or reviews. The journal is dedicated towards dissemination of knowledge related to the advancement in scientific research. The prestigious interdisciplinary editorial board reflects the diversity of subjects covered in this journal. Under the realm of science and technology, the coverage includes environmental science, pure and applied mathematics, agricultural research and engineering, biology, biotechnology, bioinformatics, Healthcare sciences (including clinical medicine, preventive medicine & public health), physics, biophysics, computer science, chemistry and bioengineering, to name a few. This Journal Is Published at 3 Month intervals on January-Marc, April-June, July-September and October-December
Arjuna Subject : Umum - Umum
Articles 310 Documents
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Automatic Transfer Switch System Design on Solar Cell – Grid Hybrid Based on Android Application Washilla Audia; Yulkifli Yulkifli; Mairizwan Mairizwan; Aditya Rinaldi
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/332

Abstract

The main source of electricity supply, namely PLN, greatly affects the supply of electricity and is not always continuous in its distribution. PLN power outages cause the distribution of human activities and productivity. The solution is to create a hybrid automatic transfer switch (ATS) system. The system works automatically as a hybrid power plant using a solar cell and PLN using ATS and remote monitoring using android. This type of research is classified as laboratory experimental engineering research. This study aims to determine the power savings of PLN that flows to the load after using the ATS system, work specifications, and system design specifications. In this study, a solar cell with a maximum capacity of 20 watts was used. The results of power savings after using the ATS system in sunny weather conditions for 10 hours of irradiation with an average solar intensity of 318,551 lux is 16,84%. The system performance specifications are small, portable, and easy to operate. The values of accuracy and precision in power saving are 96,13% and 95%.  
Modeling the Relationship of Net Atomic Charge with the Activity of 5-Aminopyrazole Derivative Compounds as Antioxidants with AM1 Method Nagmah Putri Dinda Toni; Fajriah Azra; Mirella Fonda Maahury
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/334

Abstract

This study was conducted to analyze the quantitative relationship between structure and net atomic charge modeling activity of 21 5-aminopyrazole derivatives as antioxidants. This study aims to determine the value of the net atomic charge and obtain the best HKSA equation. The method used in this study is the semi-empirical method of Austin Model 1 with geometry optimization. The selection of the best equation model is done by statistical analysis using the method of correlation analysis and multiple regression with Backward to the calculated descriptor data. From the results of the study, it was found that model 1 as the HKSA equation model was chosen with the equation Log IC50 = Log IC50 = 1.648+(0.914*qN1)-(3.662*qN2)-(1.99*qC3)+( 0.004*qC4)+(1.052* qC5 )+(1.226*qN6) where n = 6 ; R = 0.724 ; R2 = 0.524 ; SE = 0.1462 ; Sig = 0.068 ; PRESS = 0.2994. This study shows that atomic charge plays an important role in enhancing antioxidant activity.
Green Synthesis and Antibacterial Activity of Silver Nanoparticles using Turi (Sesbania grandiflora Lour) Leaf Extract Wilda Amananti; Aldi Budi Riyantal; Kusnadi Kusnadi; Kawther Ameen Muhammed Saeed Aledresi
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/337

Abstract

Research has been carried out on the ability of antibacterial activity with using Ag nanoparticles with a variation of the AgNO3 mole ratio of 0.5 mM and 1.5 mM as much as 90 ml and the amount of turi leaf extract added 1 mL. The material was characterized by UV-vis spectroscopy. Determination of antibacterial activity was carried out through Escherichia coli bacteria after interacting with nanoparticles Ag. Green synthesis of silver nanoparticles can be carried out using an aqueous extract of turi leaves, with the optimum concentration of 0.5 mM AgNO3 and 1.5 mM AgNO3 being synthesized for one day at room temperature. Resulting in silver nanoparticles with energy band gap values of 3.9 eV and 3.88 Ev having antibacterial activity of Escherichia coli with inhibitory power of 5.52 mm and 6.65 mm, respectively.   
Antioxidant Activities Extracts N-Hexane, Ethyl Acetate and Methanol of Limau Sundai (Citrus nobilis Lour) Peels Melindra Mulia; Mai Efdi; Afrizal Afrizal; Niza Lian Pernadi; Devi Purnamasari
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/339

Abstract

The Limau Sundai plant (Citrus Nobilis Lour) is widely known in West Sumatra. The fruit of this plant is commonly consumed as a cooking spice. This antioxidant activity test research aims to find out the potential of Lime Sundai peel as a source of antioxidant compounds. The peel of Limau Sundai fruit is ensnared with methanol solvent and concentrated using a rotary evaporator to obtain a coarse extract. The crude extract is then partitioned successively in n-hexane and ethyl acetate so that n-hexane, ethyl acetate, and methanol extracts are obtained. Sundai lime peel has good antioxidant activity against DPPH, which is shown in the ethyl fraction of acetate, methanol, and liquid methanol. The antioxidant activity of the three fractions is smaller than vitamin C and more significant than the hexane fraction. In the ethyl acetate, methanol and methanol/aqueous fractions with concentrations of 1076, 1822, and 1372 ppm in a row can reduce 50% of DPPH radical activity.
On the Metric Dimension for Snowflake Graph Muhammad Rafif Fajri; Luthfi Hadiyan Fajri; Jamaluddin Ashari; Abdurrahman Abdurrahman; Alifaziz Arsyad
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/348

Abstract

The concept of metric dimension is derived from the resolving set of a graph, that is measure the diameter among vertices in a graph. For its usefulness in diverse fields, it is interesting to find the metric dimension of various classes of graphs. In this paper, we introduce two new graphs, namely snowflake graph and generalized snowflake graph. After we construct these graphs, aided with a lemma about the lower bound of the metric dimension on a graph that has leaves, and manually recognized the pattern, we found that dim(Snow) = 24 and dim(Snow(n,a,b,c)) = n(a+c+1).
Pandan Tea (Pandanus amaryllifolius Roxb) as Lowering Blood Sugar Levels in Type 2 Diabetes Mellitus Faza Saiqur Rahmah; Chella Sonia; Vanda Rizky Rohmatulloh; Nisrina Shabry Habibie; Muhammad Rizal Novianto
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/353

Abstract

Type 2 diabetes mellitus is a non-communicable disease caused by metabolic disorders characterized by increased blood sugar levels caused by decreased insulin secretion or insulin resistance. This research aims to make a product from pandan leaf tea that can be consumed as well as to find out whether pandan leaf tea has alkaloid, flavonoid, saponins, tannins, and polyphenols content that could lower blood sugar level. This research uses a descriptive method by collecting data based on journals and references and qualitative method by conducting organoleptic, hedonic, and phytochemistry tests. As a result, more than 50% of the respondents like the color and smell of the product very much, and more than 50% of the respondents like the taste of the product. 35 out of 68 respondents rate the product with a score 4 out of 5. And for the result of phytochemistry tests, researchers found that pandan leaf tea contains all chemical components described in research objectives. It concludes that FANDANCO Tea contains chemical compounds as described. Also, it got positive responses from the community.
Shallot (Allium cepa Lour) Peels Snack Bar as Immunomodulator for Health Improvement in the Digital Era Sella Paramitha; Amalia Salsa Billah Firdausi; Siti Fadilla; Faza Saiqur Rahmah; Muhammad Abbas Ar-Riziq; Mayu Rahmayanti
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/355

Abstract

The digital era has brought many changes, both positive and negative impacts. The challenges of this digital era cover various sectors, including the health sector. One of the effects is the radiation from electromagnetic waves due to the use of cell phones that can interfere with health in the long term, such as a decrease in the immune system. This study aims to determine the secondary metabolite content of shallot peel extract and the formulation of the snack bar as a nutraceutical product with antioxidant properties. It becomes a solution to increase the immune system or immunomodulator. An evidenced by the phytochemical screening test, which gave positive results. In addition, this snack bar also positively contains essential nutrients, such as carbohydrates, protein, and fat. From the hedonic test, the snack bar formulation has the appearance of a snack bar in general, with solid consistency and brownish-yellow color, a characteristic odor of wheat, and a savory taste with a small amount of sweetness. This snack bar formulation has the potential as an immunomodulator against the decline in the immune system. The tastes of the snack bar are acceptable to the public.
Determination of the Energy Gap (Band Gap) of SiO2/ZnO using the Impregnation Synthesis Method Imam Wahyudi Afrizon; Miftahul Khair
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/356

Abstract

SiO2/ZnO synthesis by wet impregnation method has been successfully carried out which aims to determine the optimum band gap value of SiO2/ZnO. Characterization of the optical properties of SiO2/ZnO using a UV-Drs spectrophotometer which was measured in the wavelength range of 185 – 1100 nm. Characterization results obtained in the form of absorbance values and band gap values of SiO2/ZnO nanoparticles. From this study, the absorbance values of ZnO nanoparticles were obtained at wavelengths of 330 and 335 nm. After obtaining the absorbance values, the band gap values for ZnO and SiO2/ZnO nanoparticles were analyzed, which were 3.37 eV and 3.19 eV, respectively. The decrease in the value of the band gap in ZnO is due to the presence of SiO2 dopants in ZnO which will cause the formation of a new energy band between the valence band and conduction band so as to reduce the Energy Gap (Eg).
Inert Gas Axial Flow Analysis on Thermal System with Natural Convection Condition Rio Anshari; Mairizwan Mairizwan; Fandi Oktasendra; Debi Rianto; Zulhendra Zulhendra
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 24 No. 01 (2023): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol24-iss01/338

Abstract

The Fukushima nuclear accident in 2011 became the basis for consideration of the use of gas as a coolant in nuclear reactors. This is because the convection rate of gas flow in the cooling channel can occur naturally due to differences in density and does not require the help of a pumps for the circulation of the coolant. This study aims to analyze how the flow pattern of an inert gas on a vertical-axial reference by natural convection in a thermal system. The focus of this research is to study the flow parameters of the coolant with a gas phase. This research is an experimental study. The analysis was carried out using a descriptive approach and computer simulation-assisted numerical analysis methods. The results showed that the distribution and variation of heat was radially dominant in the middle so that the coolant channel wall received less heat load. The magnitude of the pressure drop along the vertical-axial channel shows a homogeneous pattern and decreases radially from center to edge. These results indicate the use of inert gas as a coolant can be considered as an alternative coolant in heat systems that do not depend on pumps in operating conditions.
Characteristics of Mangium (Acacia mangium) Bark Extract with Some Extraction Time and Its Application to Cotton Fabric Dyeing Diana Sylvi; Ismed Ismed; Sonia Merlin
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 23 No. 04 (2022): Eksakta: Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/362

Abstract

This study aims to determine the effect of extraction time on the characteristics of mangium bark extract and its application to cotton textile coloring. This study used a completely randomized design (CRD) with 5 treatments and 3 replications, A (10 minutes extraction), B (20 minutes extraction), C (30 minutes extraction), D (40 minutes extraction) and E (50 minutes extraction). . The results showed that the difference in extraction time had a significant effect on the yield, moisture content, tannin content and color of the mangium bark extract. Extraction time of mangium bark for 40 minutes is the optimum extraction time based on analysis of yield, tannin content and color of the extract. Yield analysis at extraction time of 40 minutes obtained the highest yield of 10.72% and tannin content of 15.67%. The cotton cloth that had been dyed with mangium bark extract changed color from yellow to red. The results of the color change test on cotton cloth that had been dyed with mangium bark extract showed that the results did not show very small to small changes when soaked in hot water and detergent.

Page 17 of 31 | Total Record : 310

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