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Jurnal Eksakta: Jurnal Ilmu-Ilmu MIPA
ISSN : 14111047     EISSN : 25032364
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.
Articles
112
Articles
Comparison the Error Rate of Autoregressive Distributed Lag (ARDL) and Vector Autoregressive (VAR) (Case study: Forecast of Export Quantities in DIY)

Ningrum, Dewi Kusuma, Surono, Sugiyarto

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

Forecasting is estimating the size or number of something in the future. Regression model that enters current independent variable value, and lagged value is called distributed-lag model, if it enters one or more lagged value, it is called autoregressive. Koyck method is used for dynamic model which the lagged length is unknown, for the known lagged length it is used the Almon method. Vector Autoregressive (VAR) is a method that explains every variable in the model depend on the lag movement from the variable itself and all the others variable. This research aimed to explain the application of Autoregressive distributed-lag model and Vector Autoregressive (VAR) method for the forecasting for export amount in DIY. It takes export amount in DIY and inflation data, kurs, and Indonesias foreign exchange reserve. Forecasting formation: defining Koyck and Almon distributed-lag dynamic model, then the best model is chosen and distribution-lag dynamic forecasting is performed. After that it is performed stationary test, co-integration test, optimal lag examination, granger causality test, parameter estimation, VAR model stability, and performs forecasting with VAR method. The forecasting result shows MAPE value from ARDL method obtained is 0.475812%, while MAPE value from VAR method is 0.464473%. Thus it can be concluded that Vector Autoregressive (VAR) method is more effective to be used in case study of export amount in DIY forecasting. Keywords: Koyck; Almon; Lag; Autoregressive Distributed-Lag; Vector Autoregressive;

Saccharin Extraction And Analysis Of Drug And Food Samples By Derivative Ultraviolet (UV) Spectrophotometry

Hermanto, Sarwendah Ratnawati, Roto, Roto, Kuncaka, Agus

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

Saccharin extraction and analysis of drug and food samples was investegated by spectrophotometry ultraviolet (uv) derivative method were studied. The saccharin extraction was carried out using solvent of ethanol/chloroform (2:8 v/v). The limit of detection (LOD) and limit of quantification (LOQ) of the proposed method were  0.50 ppm and 1.82 ppm for the second order and 0.47 ppm and 1.58 ppm for the fourth, while for the zero order were 2,75 ppm and 8,55 ppm. The calibration curve was linear in the concentration range from 20-100 ppm (R2= 0.996 for the second order and R2=0.997 for the fourth). The percent recovery of saccharin was in the range 95.20-104.40% for the second order and 97.20-102.40% for the fourth. The range of saccharin concentration (w/w) in drugs, candies and toothpaste for the fourth derivative were 1.39±0.02 mg/kg until 7.15±0.05 mg/kg, 0.21±0.01 mg/kg until 2.09±0.01 mg/kg, and 0.15±0.03 mg/kg until 0.63±0.04 mg/kg, respectively. 

Protoporphyrin IX Extraction from Quail Eggshell (Cortunix cortunix) and Its Complexity with Zn(II)

Laksono, A. Rindang Anggit, Martono, Yohanes, Riyanto, Cucun Alep

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

The aim of this research is to find the optimal condition for  Zn(II) complexation with protoporphyrin IX which is a natural coloring pigment on quail eggshell. The concentration of protoporphyrin IX extract is  0.01% (w / w) of the dried extract. The results of the complex are analyzed using Response Surface Methodology (RSM). The design used was central composite design with 3 factor variables X1 = pH (2; 4; 6), X2 = ratios (1: 3,1: 4,1: 5) and X3 = time (30 , 60, 90 ). The modeling used is linear and shows that the pH, ratio, and time factor have an influence on the complexation. This model gives the absorbance equation Y = 2.12506 - 0.049856X1 - 020316X2 - 0,00409857X3 and gives treatment in the most optimum complexation of pH 2; ratio of 1: 3; and time for 30 minutes with the absorbance of 1,293 and the desirability value of 0.825.

Rapid Analysis of Adulterated Dexamethasone in Joint-Pain Killer Traditional Herbal Medicine (THM) Using Infrared Spectroscopy

Nugroho, Ardi, Ritonga, Fany Devita

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

A rapid, non-destructive and reagent-free infrared spectroscopy combined with Partial Least Square (PLS) has been developed for the dexamethasone quantification in joint-pain killer traditional herbal medicine (THM). The main aim of this study is to select the best wavenumbers that are capable of providing the high coefficient of determination (R2), low values of Root Mean Square Error of Calibration (RMSEC), Root Mean Square Error of Cross Validation (RMSECV)  and predictive residual error sum of squares (PRESS). Finally, wavenumbers 3646, 3642, 2461, 2453, 2432, 2406, 2229, 2209, 2197, 2097, 2092, 2064, 2059, 2047, 2026, 2009, 1969, and 1513 cm-1 were selected for the prediction of dexamethasone in the joint-pain killer traditional herbal medicine. The correlation between the actual values of dexamethasone determined in joint-pain killer traditional herbal medicine using infrared spectroscopy combined with PLS revealed the R2 values of 0.9988. The RMSEC values obtained 0,009455. The PRESS and RMSECV value obtained as the results of cross-validation model selection for dexamethasone in joint-pain killer traditional herbal medicine were 0,0022721.00 and 0,02902, respectively. The high value of R2 and low value of RMSEC, RMSECV and PRESS indicated that this method had high accuracy and precision in a validated condition for the dexamethasone quantification in the joint-pain killer traditional herbal medicine. These results indicated that infrared spectroscopy combined with PLS can be an alternative method for the dexamethasone determination in joint-pain killer traditional herbal medicine.his part contains English version of the abstract. The abstract presents background, method of the research/ literary study and discussion. The abstract consist of maximum 300 words. All sentence must represent the core of research presented in good structure of sentences.

Forecasting The Exchange Rate (IDR) of US Dollar (USD) Using Locally Stationary Wavelet

Utari, Dina Tri

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

Currency exchange rate of a country to the other countries is fluctuative. The movement of the exchange rate affects the country’s economy. The exchange rate can change any time according to the market mechanism, therefore currency exchange predictions is required to determine future economic policy. Based on the impact of exchange rate in economy fluctuations, an accurate model is needed to determine the exchange rate movements.In this case, the model is Locally Stationary Wavelet (LSW). This model combines stocastic process class based on wavelet non decimated. LSW model can catch most of the information in time series data. Based on the application of LSW mtehod on the data of the rupiah against the US dollar for the period April 2016 - March 2017, it can be concluded that model provides forecasting results approaching actual data therefore it can be used for forecasting exchange rates. The value of the mean absolute percentage error (MAPE) is 0,1201293%. 

Analysis of Factors Affecting the Human Development Index in West Kalimantan Province using Data Panel Data Regression

Humaira, Uray Hety, Nugraha, Jaka

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

Development in the country is growing including in the West Borneo Province. However in 2015, the achievement of human development at the National level is quite low, while the District and City varied considerably. Human Development Index is one of the parameter for human development that are affected by many factors. In this paper, analysis for identify the factors for human development index in West Kalimantan Province by using Regression Analysis was conducted. Regression was based on time series data from 2012 until 2015. It is found that Fixed Effect Model is the best regression model with the R2 of 0.99853%. The influencing variables are Life Expectancy (AHH), Adjusted Per Capita (Expenditure), School Average (RLS), School Expectation (HLS), and Gross Regional Domestic Product at Constant Price (GRDP).

Model Analysis of Motorcycle Suspension System Using the Fourth Order of Runge-Kutta Method

Nurofi’atin, Umi, Abadi, Agus Maman

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

The suspension system is part of motorcycle that serves to absorb vibration and shocks of the road surface so as to improve the safety and comfort while driving. Motorcycle typically use double shockbreaker system which analogous to a two-spring system arranged in parallel. The aim of this researh is to analyze the model of the model of double shockbreaker motorcycle suspension system that working without outside force using passive suspension system. The data used are from damper tester experiment, then model analyzed using analytical method and the fourth order of numerical Runge-Kutta method. This research use shockbreaker observation datas that is the measurment data of spring constant and damping constant by performing damper tester using 4 different loads. The process model analysis using Matlab R2013a. Input variables are spring constant, damping constant, and the mass of the load. Methods of analysis using analytical method and the fourth order of Runge-Kutta method. While the resulting outputs are 2 spring constants, change the length of the spring, damping ratio, the optimal damping of the suspension, and the spring deflection chart against time. This model motorcycle suspension system uses solution of differential equations for the under damped suspension condition, that is the suspension system will be insulated a few moments before reaching the equilibrium position. Therefore, the resulting damping rate of the motorcycle is not optimal yet. This study found the optimal damping for each model of the suspension system. The level of accuracy of the fourth order of runge-kutta method for model analysis of the suspension system is quite high with error <0.1 and the timing of analysis is faster than the analytic method. Future research may use other methods or other input variables for more accurate analysis results.

Green Catalysts Activities of CaO Nanoparticles from Pinctada maxima Shell on Alcoholysis Reaction

Wahyuningsih, Kendri, Jumeri, Jumeri, Wagiman, Wagiman

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

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Abstract

Pinctada maxima shells from West Nusa Tenggara has natural minerals called calcite that can be decomposed into CaO compounds as a green catalyst that heterogeneous, base and environmentally friendly. CaO compounds in the nanometer scale is one option as an alternative substitute or replacement of the use of homogeneous catalysts. The purpose of this study was to test the catalytic activity of CaO compound from the pearl shells (P. maxima) based on particle size. The catalytic activity test has been measured against the percentage of yield of methyl ester produced by alcoholysis reaction. Characterization of nano-CaO compounds has been done using X-ray powder diffraction (XRD), Brunauer Emmett Teller (BET), scanning electron microscope energy-dispersive X-ray spectroscopy (SEM-EDX), transmittance electron microscopy (TEM), while methyl esters has been analyzed using the ASTM method. CaO catalyst on the nanometer-scale have more effective catalytic activity than micrometer scale with the yield percentage of methyl ester obtained are 81,61% and 30,71%, respectively. The results of methyl ester characterization by ASTM method has shown that methyl ester has specification that are close to diesel oil, so it can be used as an alternative or substitution on diesel engine.

Analysis of Factors Affecting the Human Development Index in West Kalimantan Province using Data Panel Data Regression

Humaira, Uray Hety, Nugraha, Jaka

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Original Source | Check in Google Scholar |

Abstract

Development in the country is growing including in the West Borneo Province. However in 2015, the achievement of human development at the National level is quite low, while the District and City varied considerably. Human Development Index is one of the parameter for human development that are affected by many factors. In this paper, analysis for identify the factors for human development index in West Kalimantan Province by using Regression Analysis was conducted. Regression was based on time series data from 2012 until 201. It is found that Fixed Effect Model is the best regression model with the R2 of 0.99853%. The influencing variables are Life Expectancy (AHH), Adjusted Per Capita (Expenditure), School Average (RLS), School Expectation (HLS), and Gross Regional Domestic Product at Constant Price (GRDP).

Model Analysis of Motorcycle Suspension System Using the Fourth Order of Runge-Kutta Method

Nurofi’atin, Umi, Abadi, Agus Maman

Eksakta: Jurnal Ilmu-Ilmu MIPA VOLUME 18, ISSUE 2, August 2018
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Original Source | Check in Google Scholar |

Abstract

The suspension system is part of motorcycle that serves to absorb vibration and shocks of the road surface so as to improve the safety and comfort while driving. Motorcycle typically use double shockbreaker system which analogous to a two-spring system arranged in parallel. The aim of this researh is to analyze the model of the model of double shockbreaker motorcycle suspension system that working without outside force using passive suspension system. The data used are from damper tester experiment, then model analyzed using analytical method and the fourth order of numerical Runge-Kutta method. This research use shockbreaker observation datas that is the measurment data of spring constant and damping constant by performing damper tester using 4 different loads. The process model analysis using Matlab R2013a. Input variables are spring constant, damping constant, and the mass of the load. Methods of analysis using analytical method and the fourth order of Runge-Kutta method. While the resulting outputs are 2 spring constants, change the length of the spring, damping ratio, the optimal damping of the suspension, and the spring deflection chart against time. This model motorcycle suspension system uses solution of differential equations for the under damped suspension condition, that is the suspension system will be insulated a few moments before reaching the equilibrium position. Therefore, the resulting damping rate of the motorcycle is not optimal yet. This study found the optimal damping for each model of the suspension system. The level of accuracy of the fourth order of runge-kutta method for model analysis of the suspension system is quite high with error <0.1 and the timing of analysis is faster than the analytic method. Future research may use other methods or other input variables for more accurate analysis results.