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Dynamic Modeling and Forecasting Data Energy Used and Carbon Dioxide (CO2) Edwin Russel; Wamiliana; Nairobi Saibi; Warsono; Mustofa Usman; Jamal I. Daoud
Science and Technology Indonesia Vol. 7 No. 2 (2022): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The model of Vector Autoregressive (VAR) with cointegration is able to be modified by Vector Error Correction Model (VECM). Because of its simpilicity and less restrictions the VECM is applied in many studies. The correlation among variables of multivariate time series also can be explained by VECM model, which can explain the effect of a variable or set of variables on others using Granger Causality, Impulse Response Function (IRF), and Forecasting. In this study, the relationship of Energy Used and CO2 will be discussed. The data used here were collected over the year 1971 to 2018. Based on the comparison of some criteria: Akaike Information Criterion Corrected (AICC), Hannan-Quin Information Criterion (HQC), Akaike Information Criterion (AIC) and Schwarz Bayesian Criterion (SBC) for some VAR(p) model with p= 1,2,3,4,5, the best model with smallest values of AICC, HQC, AIC and SBC is at lag 2 (p= 2). Then the best model found is VECM (2) and further analysis such as Granger Causality, IRF, and Forecasting will be based on this model.

Tritirachium oryzae and Other Endophytic Mediated Jambu Bol (Syzygium malaccense) are Potential as an Antioxidant Yustina Hapida; Elfita Elfita; Hary Widjajanti; Salni
Science and Technology Indonesia Vol. 7 No. 2 (2022): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Natural bioactive substances have been discovered produced of intracellular fungi. Intracellular fungi, as well as endophytic fungi, it can be found in organs are leaves, stems, roots, fruits, flowers, and seeds. This study aimed to specify for antioxidant activity of intracellular fungi Jambu Bol (Syzygium malaccense) mediated and identify secondary metabolites compounds. The liquid culture was partitioned with ethyl acetate solvent. Using chromatographic techniques, extracts were separated from their secondary metabolites with antioxidant activity apply the DPPH procedure. Its chemical structure was determined using NMR spectroscopic research, and endophytic fungi were recognized using phenotypic characteristics and molecular classification. The endophytic fungus isolation yielded four isolates: YF11, YF12, YF13, and YF14. YF12, with an IC50 of 53.03 g/mL, was the fungus that exhibited good antioxidant activity. Pure chemical secondary metabolites compounds were identified as 2-(4-hydroxyphenyl)-4-methoxytetrahydrofuran-3-ol. Tritirachium oryzae was identified as the endophytic fungus YF12 based on morphological studies and a phylogenetic tree. To boost its antioxidant activity, more study is needed to perform a semi-synthetic reaction on this pure molecule

Mg/Al-chitosan as a Selective Adsorbent in The Removal of Methylene Blue from Aqueous Solutions Patimah Mega Syah Bahar Nur Siregar; Aldes Lesbani; Risfidian Mohadi
Science and Technology Indonesia Vol. 7 No. 2 (2022): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The use of dyes in the textile industry is detrimental to aquatic biota and humans. Pollution caused by dye waste can be overcome by adsorption methods using adsorbents such as LDH. LDH is known as an adsorbent that is often found in the process of removing dye waste, but repeated use is not effective. This can be overcome by the LDH modification process using a supporting material such as chitosan. Modification of LDH can be done using coprecipitation or precipitation simultaneously at pH 10. XRD analysis where the peaks that appear in Mg/Al-chitosan are similar to the typical peaks of the constituent materials, namely Mg/Al and chitosan. This is confirmed by FTIR analysis where the spectrum that appears in Mg/Al-chitosan is similar to the spectrum in Mg/Al and chitosan. As well as BET analysis where there is an increase in the surface area of Mg/Al after being modified to Mg/Al-chitosan from 5.845 m2/g to 24.556 m2/g. In this study, the selectivity process for the dye mixture was carried out first with the most selective dye for the Mg/Al-chitosan adsorbent was methylene blue. Methylene blue was continued for adsorption processes such as isotherm adsorption kinetics and adsorption thermodynamics as well as adsorbent regeneration studies. The results showed that at 90 minutes the adsorption reached equilibrium. The adsorption capacity of Mg/Al increased after modification using chitosan from 84.746 mg/g to 108.696 mg/g. The adsorption process follows the Langmuir isotherm type where adsorption occurs chemically (monolayer). Regeneration studies show that Mg/Al-chitosan is an adsorbent that can be used repeatedly with stable adsorption effectiveness until the fifth cycle.

The Enhancement Solubility and Stability of Erythromycin Formatted in Solid Lipid Nanoparticles by Utilizing PVA as Stabilizer Mardiyanto; Budi Untari; Najma Fithri Annuria; Ady Mara; Andre Agung Aprianto; Gustina Emilia Ningsih
Science and Technology Indonesia Vol. 7 No. 2 (2022): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Infectious diseases have changed the world order today where the infection is the main cause of illness and death in the world. Erythromycin is a macrolide antibiotic that can generally inhibit the growth of Staphylococcus aureus and resistant strains. The free molecule of erythromycin in the part of the body does not reach Staphylococcus aureus because it is degraded by the first-pass effect. Nanoparticles can minimize damage to active substances due to first-pass effects because the particles have been protected by biopolymers leading to the minimizing damage of active substances. Formulation of nanoparticles loading erythromycin was used with the following variations in the amount of erythromycin 25 to 100 mg. Erythromycin was formulated by the coated polymer to changes the physics of the erythromycin into a particle. Preparation of erythromycin into nanoparticles was utilized stearic acid polymer, PEG-400, and polyvinyl alcohol using hot homogenization and ultrasonication method. Results showed that the optimum formula was the second formula (F2) with a percentage of encapsulation efficiency of 80.89773±0.11364. The results of the characterization of submicron particle formation such as morphology, diameter (particle size) and distribution (PDI) of F2 were spherical 518.6 nm; 0.096 PDI; and a zeta potential value of -12 mV respectively. The particles loading erythromycin were successfully increasing the stability of erythromycin for up to 5 cycles in terms of the heating-cooling-cycles test and also the solubility in SIF.

Facility Location Problem of Dynamic Optimal Location of Hospital Emergency Department in Palembang Robinson Sitepu; Fitri Maya Puspita; Ide Lestari; Indrawati; Evi Yuliza; Sisca Octarina
Science and Technology Indonesia Vol. 7 No. 2 (2022): April
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The Emergency Department (ED) is one part of a hospital that provides initial treatment for patients who suffer from illness and injury, which can threaten their survival. The importance of integrated care in the ED is one of the keys to successfully treating patients at an advanced level. This becomes complex because the ED works in a team consisting of various multi-disciplinary sciences and limited human resources, facilities, and infrastructure. In the City of Palembang, 23 hospitals have emergency room facilities from 18 Sub-Districts, by using the TOPSIS (Technique for Others Reference by Similarity to Ideal Solution) method to vary the distance (radius) the optimal location of the emergency department is obtained according to the number of hospitals that have emergency room facilities, namely Ilir Timur I District, Ilir Barat I District, Sukarami District, and Plaju District. Based on the formulation of the p-median model and the completion of the TOPSIS method, the order of Districts that have optimal locations from 18 Sub-Districts that have emergency department facilities in the City of Palembang is obtained.

Electro-adsorption as a Hybrid Processing to Removed Oil from Synthetic Oily Solution by Using Activated Carbon and Iron Electrodes Lia Cundari; Bazlina Dawami Afrah; Suci Dwijayanti; Alvina Suryadinata; Aldi Ramadhani
Science and Technology Indonesia Vol. 7 No. 3 (2022): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Biosolar contains oil, fatty acids, emulsifiers, bactericides, and other chemicals. If the oil contents are mixed with water, it will become hazardous waste and affect drinking water sources, endanger human health, air pollution, affect agricultural production, and damage the natural landscape, so the oil content must be processed to reduce its hazardous content. One of the methods used in treating oily solutions is adsorption. The adsorption method for oily solution treatment is ineffective because it requires several stages, so the required capital is relatively larger and takes longer. Electro-adsorption is one of the methods that is being developed for treating oily solutions. Electro-adsorption is a hybrid separation technology to break down oil emulsions in wastewater and some other organic content. The purpose of this study is to characterize the activated carbon and determine the effect of voltage and time on synthetic oily solution treatment in terms of COD value and oil-fat content. A synthetic oily solution is made by mixing 1 g of biosolar/B30 into the water from the Musi River to a volume of 1 L. The application of the electro-adsorption method uses commercially activated carbon as an adsorbent and iron as an electrode. Variations given to the process with voltage 0, 5, 10, 15 V and time 0, 5, 10, 15, 20, and 25 minutes. The characteristic of activated carbon showed a size change in the pore size from 2.58 µm to 1.98 µm and a reduction of surface area from 740 (±180) m2/g to 730 (±120) m2/g. The electro-adsorption method was effective in treating oily solutions. The decrease of COD reaches the maximum level at a voltage 10 V for 25 minutes, which was 75.92% from 62.33 mg/L to 15 mg/L initially, while the concentration of oil-fat obtains the maximum level at a voltage of 5 V for 5 minutes that is equal to 99.65%, initially 303.19 mg/L to 1.05 mg/L. The optimum condition of the electro-adsorption process in synthetic oily solution was at the voltage of 5 V and a time of 5 minutes. The electro-adsorption process is an effective method to treat synthetic oily solutions.

Validation of Mercury Speciation Analysis in River Around Artisanal Small-Scale Gold Mining Area in West Nusa Tenggara, Indonesia Dhony Hermanto; Nurul Ismillayli; Nindi Herdiyanti; Siti Raudhatul Kamali; Soraya Aulia
Science and Technology Indonesia Vol. 7 No. 3 (2022): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

A method for determining mercury concentration using a mercury analyzer in a river water sample was validated according to ISO/IEC 17025. Analytical performance including linear range, limit of detection, precision and accuracy were evaluated. Mercury speciation profile was obtained from Pelangan River at three areas within Dusun Rambut Petung, an area with the highest amount of artisanal small-scale gold mining (ASGM) in Lombok, West Nusa Tenggara. Then, their concentration in each species was measured using sequential extraction. Good curve linearity was obtained in the concentration range of 0.1-5.0 µg/L and the limit of detection was 0.014 µg/L. The developed method has good precision and accuracy with a RSD value <10% and a recovery of 94.16-101.91%. The detected fraction of mercury in the Pelangan river is organomercury, elemental mercury, and sulfide-bound species with each concentration of 0.732±0.032; 0.350±0.027; and 0.850±0.027 µg/L, respectively. The measurement results showed conformity with the reference method using CV-AAS. Therefore, this method can be applied to determine mercury levels in water for monitoring environmental quality.

Droplet Combustion and Thermogravimetric Analysis of Pure Coconut Oil, Clove Oil, and Their Mixture Adhes Gamayel; MN Mohammed; Mohamad Zaenudin; Eddy Yusuf
Science and Technology Indonesia Vol. 7 No. 3 (2022): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

The droplet combustion and thermal behavior of pure coconut oil (PCO), clove oil, and their mixture were experimentally investigated. The mixture fuels were PCO and clove oil at the percentage of 10% based on volume (PCO-CO10). The experimental method uses droplet combustion and thermogravimetric analysis. The fuel droplet was suspended in the junction of k-type thermocouple and ignited by a coil heater. The ignition and combustion processes of droplets were recorded using a digital single-lens reflex camera at 25 fps. Thermogravimetric analysis with alumina crucible was prepared to investigate the thermal behavior of fuel. The result showed that the sequence of ovoid flame for PCO and PCO-CO10 take place until 0.4 second and 0.44 second, respectively. Complete combustion was explained in that sequence. The ovoid flame was formed when eugenol, terpene, and lauric acid were evaporated first in both PCO and PCO-CO10. Minimum ovoid flame takes place in clove oil due to soot tendency in the burning process that marked flame as the open tip. PCO-CO10 has the highest peak temperature due to the presence both of double carbon chains in fatty acid and aromatic ring structures, which were easy to decompose in high energy input. Clove oil was the lowest onset temperature, which indicates more volatile matter in this fuel and PCO has the highest thermal stability due to the fatty acid component in their fuel.

Pattern Recognition using Multiclass Support Vector Machine Method with Local Binary Pattern as Feature Extraction Nursyiva Irsalinda; Sugiyarto Surono; Indah Dwi Ratna Sary
Science and Technology Indonesia Vol. 7 No. 3 (2022): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Corn is an essential agricultural commodity since it is used in animal feed, biofuel, industrial processing, and the manufacture of non-food industrial commodities such as starch, acid, and alcohol. Early detection of diseases and pests of corn aims to reduce the possibility of crop failure and maintain the quality and quantity of crop yields. A decision tree is a nonparametric classification model in statistical machine learning that predicts target variables using tree-structured decisions. The performance of this model can increase significantly if the continuous predictor variables are discretized into valid categories. However, in some cases, the result does not provide satisfactory performance. The possible cause is the ambiguity in discretizing predictor variables. The incorporation of fuzzy membership functions into the model to resolve discretization ambiguity issues. This work aims to classify diseases and pests of corn plants using the decision tree model and improve the model’s performance by implementing fuzzy membership functions. The main contribution of this work is that we have shown a significant improvement in the decision tree model performance by implementing fuzzy membership functions; S-growth, triangle, and S-shrinkage curves. The proposed fuzzy model is better than the decision tree model, with an average performance increase from the largest to the smallest; kappa (12.16%), recall (11.8%), F-score (9.71%), precision (5.08%), accuracy (3.23%), specificity (1.94%), and AUC (0.49%). The combination of bias and variance generated by the proposed model is quite small, indicating that the model is able to capture data trends well.

Performance Improvement of Decision Tree Model using Fuzzy Membership Function for Classification of Corn Plant Diseases and Pests Yulia Resti; Chandra Irsan; Muflika Amini; Irsyadi Yani; Rossi Passarella; Des Alwine Zayantii
Science and Technology Indonesia Vol. 7 No. 3 (2022): July
Publisher : Research Center of Inorganic Materials and Coordination Complexes, FMIPA Universitas Sriwijaya

Corn is an essential agricultural commodity since it is used in animal feed, biofuel, industrial processing, and the manufacture of non-food industrial commodities such as starch, acid, and alcohol. Early detection of diseases and pests of corn aims to reduce the possibility of crop failure and maintain the quality and quantity of crop yields. A decision tree is a nonparametric classification model in statistical machine learning that predicts target variables using tree-structured decisions. The performance of this model can increase significantly if the continuous predictor variables are discretized into valid categories. However, in some cases, the result does not provide satisfactory performance. The possible cause is the ambiguity in discretizing predictor variables. The incorporation of fuzzy membership functions into the model to resolve discretization ambiguity issues. This work aims to classify diseases and pests of corn plants using the decision tree model and improve the model’s performance by implementing fuzzy membership functions. The main contribution of this work is that we have shown a significant improvement in the decision tree model performance by implementing fuzzy membership functions; S-growth, triangle, and S-shrinkage curves. The proposed fuzzy model is better than the decision tree model, with an average performance increase from the largest to the smallest; kappa (12.16%), recall (11.8%), F-score (9.71%), precision (5.08%), accuracy (3.23%), specificity (1.94%), and AUC (0.49%). The combination of bias and variance generated by the proposed model is quite small, indicating that the model is able to capture data trends well.

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Journal Mail Official
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Location
Kab. ogan ilir,

Sumatera selatan

INDONESIA