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Faculty of Mathematics and Natural Sciences Universitas Islam Indonesia Jl. Kaliurang Km 14, Ngaglik, Sleman, Yogyakarta, 55584
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INDONESIA
EKSAKTA: Journal of Sciences and Data Analysis
Published by Universitas Islam Indonesia
ISSN : 27160459     EISSN : 27209326     DOI : 10.20885
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Chemistry Earth & Planetary Sciences Materials Science & Nanotechnology
Ekstakta is an interdisciplinary journal with the scope of mathematics and natural sciences that is published by Fakultas MIPA Universitas Islam Indonesia. All submitted papers should describe original, innovatory research, and modelling research indicating their basic idea for potential applications. The Journal particularly welcomes submissions that focus on the progress in the field of mathematics, statistics, chemistry, physics, biology and pharmaceutical sciences.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 231 Documents
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Pengaruh Pemberian Dosis Vitamin C Dan Waktu Pemeliharaan Terhadap Kematian Ikan Nila Menggunakan Regresi Logistik Budi Setiawan; Jaka Nugraha
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 12, ISSUE 2, August 2011
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

Penelitian ini dilaksanakan di Perikanan Kolam Jaring Apung JD-Cirata, Cianjur-Jawa Barat. Penelitian ini bertujuan untuk mengetahui pengaruh pemberian dosis vitamin C dan waktu pemeliharaan terhadap kematian ikan nila. Analisis statistik yang digunakan adalah analisis regresi logistik biner. Variabel respon adalah kematian ikan nila dan variabel penjelasnya adalah dosis vitamin C dan waktu pemeliharaan. Berdasarkan hasil analisis diperoleh kesimpulan bahwa pemberian dosis vitamin C dan waktu pemeliharaan berpengaruh terhadap kematian ikan nila. Probabilitas kematian ikan nila terkecil ketika pemberian dosis vitamin C 650 ml pada waktu pemeliharaan bulan ke-3, yaitu sebesar 0.0632 atau 6.32%. Semakin besar pemberian dosis vitamin C akan menekan kematian ikan, demikian juga semakin besar usia ikan maka peluang ikan akan hidup juga semakin besar.
Analysis of Total Antioxidant Capacity on Ingredients of Lotek Menu by Ferric Reducing Antioxidant Power Assay Reni Banowati Istiningrum
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 13, ISSUE 1-2, August 2013
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/eksakta.vol13.iss1-2.art5

Abstract

Total Antioxidant Capacity (TAC) determination has been made in the vegetable component of lotek with Ferric Reducing Antioxidant Power (FRAP) methods. Samples was crushed and then extracted with water as a polar solvent and centrifuged. The residue was extracted again with acetone as a non-polar solvent. The extract is then reacted with FRAP reagent and the absorbance measured by UV-Vis spectrophotometer at 595 nm. TAC values expressed as mM/mL extract of vegetables component of lotek for the water extract of green beans, peanuts, bean sprouts, cabbage, cucumbers, tomatoes, and spinach respectively is 2,72; 6,79; 1,26; 0,89; 0,33; 1,86; 1,85 mM /mL extract, while the acetone extract is 1,42; 5,41; 0,44; 0,32; 0,25; 1,09; 0,93 mM/mL extract. The three largest contribution to the total TAC is a water extract of peanuts, acetone extract of peanut and water extract of green beans respectively is 25,56; 21,16 and 10,66%.Keywords: lotek, TAC, FRAP, spectrophotometer UV-Vis
A Highly Sensitive Electrochemical Glucose Sensor By Nickel-Epoxy Electrode With Non-Enzymatic Sensor Riyanto Riyanto
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 16, ISSUE 1, February 2016
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/eksakta.vol16.iss1.art1

Abstract

The preparation of new sensor for glucose was based on the fact that glucose can be determined by non-enzymatic glucose oxidase. The Ni metals (99.98% purity, 0.5 mm thick, Aldrich Chemical Company) was used to prepare Ni-Epoxy electrode. The Ni-epoxy electrodes were prepared in square cut of 1 cm and 1 mm by length and wide respectively. The Ni metal electrodes were connected to silver wire with silver conducting paint prior covered with epoxy gum. The prepared of nickel-epoxy modified electrode showed outstanding electro catalytic activity toward the oxidation of glucose in alkaline solution. The result from this research are correlation of determination using Nickel-Epoxyelectrode for electroanalysis of glucose in NaOH was R2 = 0.9984. LOQ, LOD and recovery of the Nickel-Epoxy electrode towards glucose were found to be 4.4 μM, 1.48 μM and 98.19%, respectively. The Nickel-Epoxy wire based electrochemical glucose sensor demonstrates good sensitivity, wide linear range, outstanding detection limit, attractive selectivity, good reproducibility, high stability as well as prominent feasibility use of non-enzymatic sensor for monitoring glucose in human urine owing to its advantages of low cost, simple preparation and excellent properties for glucose detection.
Synthesis of Chalcones Substituted with Nitro and Hydroxyl Group in Alkaline Medium Lina Fauzi'ah; Tutik Dwi Wahyuningsih
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 16, ISSUE 2, August 2016
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/eksakta.vol16.iss2.art5

Abstract

Telah dilakukan sintesis turunan senyawa kalkon tersubstitusi gugus nitro dan hidroksi melalui reaksi kondensasi Claisen Schmidt. Tujuan penelitian ini adalah untuk mensintesis senyawa kalkon yang tersubstitusi gugus hirdoksi dan nitro dalam medium basa, dan mempelajari pengaruh gugus tersebut dalam reaksi kondendasi. Kalkon 1 disintesis dari 4-nitroasetofenon dan vanilin menggunakan katalis NaOH 60% (b/v dalam akuades) melalui pengadukan selama 24 jam. Kalkon 2 didapatkan dari reaksi antara 4-nitroasetofenon dan veratraldehida dengan katalis NaOH 15% selama 4 jam, sedangkan kalkon 3 disintesis dari 4-nitroasetofenon dan 6-nitroveratraldehida dalam 5% NaOH 10 tetes. Produk hasil sintesis dikarakterisasi dengan FTIR, GC-MS dan 1H-NMR.Hasil penelitian menunjukkan bahwa senyawa kalkon telah berhasil disintesis dengan rendemen berturut-turut sebesar 16,80; 75,83; dan 44,11 % dalam medium basa. Dari penelitian ini, dapat disimpulkan bahwa adanya gugus hidroksi dari sumber aldehida aromatik pada kalkon 1 menghambat terjadinya reaksi, sedangkan gugus nitro yang terikat pada aldehida aromatik menjadi kendala pada reaksi kalkon 3 karena sifatnya yang sensitif terhadap cahaya.
Survival Analysis of Child Patient Diarrhea Using Kaplan Meier Method and Rank Log Test Muhammad Muhajir; Yayi Diyah Palupi
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 18, ISSUE 1, February 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/eksakta.vol18.iss1.art8

Abstract

Diarrhea being one of public health problems that important because it is third major contributor the pain children in various countries including indonesia. This research using data from islam hospital medical record jakarta in january 2017 shows that diarrhea cases were occupying the highest rank of various types of disease in patients children, using indicators long healed patients , the age of , andsex. Methods used to determine function survival who dominated in patients children are Kaplan Meier and Log Rank. The results of the analysis method kaplan meier got that patients male had the probability of healed longer than for patients female as well as patients age of 6- 11 years had the probability healed longer than the age of ≤ 5 years. To Log Rank test got that there is no significant difference between the survival function based on sex and age patients.
Preliminary Study of Photocatalytic Degradation of Methylene Blue Dye using Magnetic Alginate/Fe3O4 (Alg/Fe3O4) Nanocomposites Ganjar Fadillah; Muhamad Allan Serunting
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 19, ISSUE 1, February 2019
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/eksakta.vol19.iss1.art3

Abstract

The Magnetic compound, Fe3O4, is one of the compounds that is easily hydrolyzed and oxidized. A coating method was presented in this study to prevent the process. The modifications of Fe3O4 were carried out by supporting alginate as natural polymers on the surface of Fe3O4. Preparation of magnetic alginate/Fe3O4 (Alg/Fe3O4) nanocomposite has been successfully synthesized. Alg/Fe3O4 material was synthesized using the coprecipitation method with Fe2+; Fe3+ (with molar ratio 1:2) and alginate 1% as precursors. Synthesized Alg/Fe3O4 nanoparticles were characterized by Fourier Transform Infrared Spectroscopy (FTIR), DelsaTM Nano C Particle Analyzer, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). The Alg/Fe3O4 has an average diameter of 13.70 nm. Photodegradation test of synthetic methylene blue (MB) dye was found at pH 5.0 and irradiation time under UV245 for 60 minutes. The degradation results showed that the percentage of MB dye removal reached more than 90%.
Production of Bioethanol from Rice Straw Assisted by Cellulosic Enzyme Oyster Mushroom Stem Using Simultaneous Saccharification and Fermentation (SSF) Tatang Shabur Julianto; M. Arsyik Kurniawan S; Ikhwan Arifin
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 19, ISSUE 2, August 2019
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/eksakta.vol19.iss2.art9

Abstract

Bioethanol is an alternative energy source to replace fossil fuels that can be produced from agricultural waste such as rice straw. The fermentation process can help hydrolyze lignocellulosic compounds in rice straw into simple sugars and convert them into bioethanol. This study aims to determine the effect of fermentation time and the amount of intracellular cellulase enzyme extract from oyster mushroom stem on the levels of biethanol produced. The method used in making bioethanol is Simultaneous Saccharification and Fermentation (SSF). The bioethanol produced was then analyzed by gas chromatography and UV-Vis spectrophotometer. The result showed that the highest level of bioethanol was 14.52% obtained at 10 days fermentation time and the amount  of cellulase enzyme extract was 25 mL.
Redox Reaction in the Cyclization-aromatization of (R)-(+)-Citronellal with FeCl3/Acetic Anhydride Edy Cahyono; Muchalal Muchalal; Harno Dwi Pranonowo
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 11, ISSUE 2, August 2010
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

 The effects of temperature, time of reaction, and the reactants mole ratio on the cyclization-acetylation of (R)-(+)-citronellal with FeCl3/acetic anhydride were studied.  Isopulegyl acetate (IPA) and neoisopulegyl acetate (NIPA) were obtained as the main products at room temperature (mole ratio of citronellal: acetic anhydride: FeCl3 = 6:12:1). Both products are relatively fixed after the 30th minute. The average concentration of IPA at 30-180 minutes was 44.71%, while the average concentration of NIPA was 28.47%. Increasing temperature (80 oC) and the amount of acetic anhydride (mol ratio 2:6:1) gave p-cymene (17.53%) and citronellyl acetate (11.31%). Autoredoks reaction on the transformation of citronellal into p-cymene and citronellyl acetate was studied with the carbon oxidation number concept. Key words: (R )-(+)- citronellal, cyclization-aromatization, FeCl3,  p-cymene, redox
Editorial Member eksakta ekskata eksakta
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 19, ISSUE 1, February 2019
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

Editorial Member
Pengaruh Pola Agitasi pada Reaksi Transesterifikasi Minyak Jelantah Warung Pecel Lele Menggunakan Katalis Kitosan Tatang Shabur Juliantoa, Thorikul Huda
EKSAKTA: Journal of Sciences and Data Analysis VOLUME 13, ISSUE 1-2, August 2013
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20885/eksakta.vol13.iss1-2.art4

Abstract

Effect of agitation on the transesterification reaction of waste cooking oil from pecel lele food stalls around UII campus using chitosan catalyst. Transesterification reaction was done by adding 46 grams of chitosan and 123 mL metanol tothe reactor. The mixture was stirred for 30 minutes to distribute methanol into chitosan. Furthermore,500 mL (460 grams) of cooking oil (= 0.916 g / mL) was add into reactor and agitated at 65oC within two hours using 30 rpm speed . Agitation was performed with several variations of the direction of stirring , one way stirring, stirring 2 ways round the turn at intervals of 5, 10 and 15 minutes. The results show that only 49,95% methyl ester yieldwas obtained (methyl palmitate, methyl-9-octadecenoate , methyl-3-oxooctadecanoate), produced by one directional rotation. Two ways agitation gives methyl ester results on average by 30.41 % . The number of methyl ester was decreased when treated with two way stirring well in intervals of 5 seconds (30.34 %) , 10 seconds (29.97 %) and 15 seconds (30.94 %). Methyl ester product was only sligtly, presumably because the raw material is very bad used cooking oil. It can be indicated from thehigh acid number 8.11 mg/L. and the number of chemical components in addition to triglycerides which may interfere with or hinder the contact between the reactants (chitosan , methanol and triglycerides).Keywords: used cooking oil, chitosan, agitation, transesterification, methyl ester

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