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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 9 Documents
 1 
Search results for , issue "VOLUME 13, ISSUE 1-2, August 2013" : 9 Documents clear
Studi Simulasi Model Nested Logit dan Paired Combinatorial Logit pada Respon Multinomial Jaka Nugraha
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.art8

Abstract

Multinomial logit model (MNL) is based on independent irrelevant alternatives assumption. If there was a correlation, MNL would result bias estimator. Correlation among of choices could be accommodated by Nested logit Model (NL) and Paired Combinatorial Logit Model (PCL). This research discuss how NL and PCL model can be used for estimating parameters (regression coefficient and correlation) and comparing to MNL in discrete choice model. Correlation structure is tested nesting correlation and correlation overlap. Paramaters in the models are estimated using maximum likelihood method. Simulated data generated using software R.3.0.1. Based on simulations data with nested correlation, NL model more appropriate than do MNL. But on data with overlapping correlation, the maximum likelihood estimator is not unique.Keywords : Multinomial logit, Nested logit, Paired Combinatorial Logit, maximum likelihood
Synthesis, Characterization and Aplication of TiO2 Alumina Pillared Montmorillonite Photocatalyst Iwan Sumarlan, Is Fatimah, Karna Wijaya
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.art3

Abstract

Dispersion of TiO2 on montmorillonite pillared aluminium has been done successfully. The photocatalyst were prepared by intercalation of Al13 onto natural montmorillonite and then calcined at 500oC. Titania dispersion onto aluminium pillared montmorillonite was carried out by impregnation method at the theoritic concentration of 0.4, 0.8, 1 and 3% titania. The photocatalyst then characterized by XRD, porosimetry, SEM and Diffuse Reflectance Visible methods. Results of characterization showed that the basal spacing and specific surface area as well as total pore volume were decreased after dispersion of TiO2 on PILM, meanwhile SEM image exhibited that beside in the pores of PILM, the TiO2 was also dispersed on the surface of PILM. DR UV characterization result indicated that the band gap of TiO2 dispersed PILM for Ti/PILM 0,8%, Ti/PILM 1% and Ti/PILM 3% was 3.66, 3.19 and 3.19 eV respectively. Photodegradation optimum of methyl orange was found to be at Ti/PILM 1%Keywords : montmorillonite, pillarization, photocatalyst, methyl orange, TiO2
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
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
Preparation of Chitin, Study of Physicochemical Properties and Biopesticide Activities Yuli Rohyami; 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.art6

Abstract

Chitin was preparated from shrimp shells by chemically method. Preparation was carried out by deproteination shrimp shells powder < 150 mesh with 1 - 2 M NaOH, demineralization followed by reaction with 1.0 M HCl and depigmentation with (1 : 2 : 4, v/v) of chloroform : methanol : water. Physicochemical properties of chitin was determined from characterization of infrared spectra, ash value, loss on drying and total of nitrogen. Biopesticide activities of chitin was done to pest Bemisia tabaci at guava leaves with various concentration from 0.5 to 2.0 % chitin on 3 % v/v acetic acid. This study indicated that concentration of NaOH on deproteination process effected to its physicochemicals properties. Effectivity of 2 M NaOH on deproteination reaction was higher than 1 M NaOH . The degree of chitin deacetylation from 2 M NaOH was 13.61% and had lower molar ratio of total nitrogen. The degree of deacetylation of chitin from 1 M NaOH had lower and had higher molar ratio of total nitrogen. Physicochemicals properties of chitin quite an impact on its ability to reduce pest Bemisia tabaci. Biopesticide activity assay showed that treatment for 2 days on average mortality rate of 13.83%. Deacetylation of chitin which has a higher degree have a greaterability biopesticide with a mortality rate of up to 38.24%. This study the effect of deproteination process to biopesticide activities of chitin.Key Words : chitin, degree of deacetilation, molar ratio, biopesticide, Bemisia tabaci
Physical-Mechanical Properties And Microstructure Of Breadfruit Starch Edible Films With Various Plasticizer Cut Fatimah Zuhra Marpongahtun
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.art7

Abstract

Breadfruit contains starch can be used as raw material of edible film. Research on preparation of edible films using various types of plasticizer (xylitol, sorbitol and PEG 400) has been done. The edible films were evaluated of physical-mechanical properties and microstructure. The results of this study indicate that the addition of plasticizer effect on the physical and mechanical characteristics, the edible film thickness, tensile strength and water vapor transmission rate greater using PEG 400 but percent elongation smaller than xylitol and sorbitol. Surface analysis of film was performed using Scanning Electron Microscopy (SEM) method.Keyword : Edible Film; Pati Sukun; Plasticizer; Silitol; Sorbitol ; PEG 400
Chemical Stability of Cd(II) and Cu(II) Ionic Imprinted Amino-Silica Hybrid Material in Solution Media Buhani, Narsito, Nuryono, Eko Sri Kunarti
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.art1

Abstract

Chemical stability of Cd(II) and Cu(II) ionic imprinted hybrid material of (i-Cd-HAS and i-Cu-HAS) derived from silica modification with active compound (3-aminopropyl)-trimethoxysilane (3-APTMS) has been studied in solution media. Stability test was performed with HNO3 0.1 M (pH 1.35) to investigate material stability at low pH condition, CH3COONa 0.1 M (pH 5.22) for adsorption process optimum pH condition, and in the water (pH 9.34) for base condition. Material characteristics were carried out with infrared spectrophotometer (IR) and atomic absorption spectrophotometer (AAS). At interaction time of 4 days in acid and neutral condition, i-Cd-HAS is more stable than i-Cu-HAS with % Si left in material 95.89 % (acid media), 43.82 % (close to neutral), and 9.39 % (base media).Keywords: chemical stability, amino-silica hybrid, ionic imprinting technique
Uji Aktivitas Ekstrak Etanol Kulit Buah Apel ( Pyrus malus, L) Terhadap Suparmia, Khusnul Khotimah Amal Fadho
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.art9

Abstract

Apple (Pyrus malus, L) is a fruit having much uses for health containing phytochemical and flavonoid substances. One of the substances contained in apple rind is quercetin. Quercetin capable to reduce vascular permeability (Mochizuki et al., 2004). The recent study has an aim to know activity of ethanol extract on apple rind to the reducing of vascular permeability thus it can used as therapies for plasma leakage in curing Dengue Blood Fever. The vascular permeability test it was done an induction method using acetate acid. Testing done on white male mice of the BALB/c strain where the mice were divided into 5 groups. The first and second groups were control groups that are a positive control were given 0.2 mg/20 g standard quersetin suspension and the negative one was given 0.5% Na CMC suspension. The third, fourth and fifth groups were treatment groups where each testing animals were given ethanol extract suspension of apple rind by dosages 0.2, 0.4, and 0.8 mg/20 g of Body Weight mice per oral. Taking data was done by measuring pigment intensities from abdominal cavity liquid had been washed with acetate saline. From percentages of vascular permeability reducing each group then analyzed using statistic analyses those were the one-way anova. If there was found any significant difference then it was continued a Tukey test and bivariate-correlation. From results in the study it was known that percentages of vascular permeability reduces of ethanol extract that were made from apple rind having dosages 0.2, 0.4, and 0.8 mg in sequences as big as 42.15%, 63.28% and 84.19%.Keywords: Pyrus malus, L, kuersetin, vascular permeability
Kinetic study of Cr(VI) Adsorption on Hydrotalcite Mg/Al with Molar Ratio 2:1 Puji Kurniawati, Bayu Wiyantoko, Angga Kurniawan, Tri Esti Purbaningtias
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.art2

Abstract

Chromium(VI) is one of the metals that is harmful to biota and humans if large amount present in environments. One method for reducing metal contamination of Cr(VI) inaqueous is by adsorption using Mg/Al hydrotalcite with molar ratio 2:1. This study is determined the effect of contact time and adsorption models of Cr(VI) adsorption on Mg/Al hydrotalcite with molar ratio 2:1. Capacity of Cr(VI) adsorption on Mg/Al hydrotalciteoccursat the optimum contact time of 180 minutes with 93.81% percent adsorption. Adsorption kinetics model equations are analyzed with first order, second order, pseudo first order, pseudo second order, Elovich equation, the equation Dumwald-Wagner and Weber-Morris equation. Analysis model of adsorption kinetics of Cr(VI) followed pseudo second order models are characterized by the highest coefficient of determination, which is 0.998.Keywords: adsorption, Mg/Al hydrotalcite, Cr(VI), adsorption kinetic models

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