Methyl esters selectivity of transesterification reaction with homogenous alkaline catalyst to produce biodiesel in batch, plug flow, and continuous stirred tank reactors

Selectivity concept is essential in establishing the best operating conditions for attaining maximum production of the desired product. For complex reaction such as biodiesel fuel synthesis, kinetic studies of transesterification reaction have revealed the mechanism of the reaction and rate constants. The objectives of this research are to develop the kinetic parameters for determination of methyl esters and glycerol selectivity, evaluate the significance of the reverse reaction in transesterification reaction, and examine the influence of reaction characteristics (reaction temperature, methanol to oil molar ratio, and the amount of catalyst) on selectivity. For this study, published reaction rate constants of transesterification reaction were used to develop mathematical expressions for selectivities. In order to examine the base case and reversible transesterification, two calculation schemes (Case 1 and Case 2) were established. An enhanced selectivity was found in the base case of transesterification reaction. The selectivity was greatly improved at optimum reaction temperature (60 C), molar ratio (9 : 1), catalyst concentration (1.5 wt.%), and low free fatty acid feedstock. Further research might explore the application of selectivity for specifying reactor configurations

Methyl esters selectivity of transesterification reaction with homogenous alkaline catalyst to produce biodiesel in batch, plug flow, and continuous stirred tank reactors

Selectivity concept is essential in establishing the best operating conditions for attaining maximum production of the desired product. For complex reaction such as biodiesel fuel synthesis, kinetic studies of transesterification reaction have revealed the mechanism of the reaction and rate constants. The objectives of this research are to develop the kinetic parameters for determination of methyl esters and glycerol selectivity, evaluate the significance of the reverse reaction in transesterification reaction, and examine the influence of reaction characteristics (reaction temperature, methanol to oil molar ratio, and the amount of catalyst) on selectivity. For this study, published reaction rate constants of transesterification reaction were used to develop mathematical expressions for selectivities. In order to examine the base case and reversible transesterification, two calculation schemes (Case 1 and Case 2) were established. An enhanced selectivity was found in the base case of transesterification reaction. The selectivity was greatly improved at optimum reaction temperature (60 C), molar ratio (9 : 1), catalyst concentration (1.5 wt.%), and low free fatty acid feedstock. Further research might explore the application of selectivity for specifying reactor configurations

Penentuan Kadar Kalium (K) Dan Kalsium (Ca) Dalam Labu Siam (Sechium Edule) Serta Pengaruh Tempat Tumbuhnya (Determination of Potassium (K) and Calcium (Ca) Content in Chayote (Sechium Edule) and the Effects with Its Growth Soil)

Chayote (sechiumeaite) is an alternative source of vegetable which is consumed largely by the community. For that reason, the research was conducted to determine the content of potassium (K) and calcium (Ca) as wll as its relation to the growth soil. The method of this research is laboratory experiments by using atomic absorption spectrometry. The result shows that the content of potassium in Palolo's chayote meat is 134.35 mg/100 g, skin and fruit meat is 269.10 mg/100 g, and in the ground is 34.02 mg/100 g. However, in Kebun Kopi's pumpkin, the content of potassium (K) is 177.42 mg/100 g in its fruit meat, 298.35 mg/100 g in its skin and fruit meat, and 88.02 mg/100 g in the soil. On the other hands the content of calcium obtained as follows: in Palolo's chayote meat is 38.53 mg/100 g, in the skin and fruit meat is 55.865 mg/100 g, and in the soil is 32.72 mg/100 g. In the area of Kebun Kopi's chayote meat is 20.535mg/100 g, in the skin and fruit meat is 30.605 mg/100 g, and in the soil is 7.682 mg/100 g. Therefore, the content of potassium and calcium obtained is higher than in the literature

Biocharcoal dari Serbuk Gergaji Kayu Cempaka (Elmerrillia Ovalis Miq) Serta Daya Adsorpsinya pada Zink dan Tembaga

Cempaka wood is a typical wood in Sulawesi Island and Maluku archipelago. This wood can be used for wood industry particularly for the manufacture of furniture. However, not only furniture can be produced from the wood but also the sawdust as the waste. This research utilized the sawdust of cempaka wood as biocharcoal to adsorb zinc and copper ions included in liquid organic fertilizer complement based on variation of weight and concentration of biocharcoal. The method used in this study was the spectrophotometry spectroDirect with sawdust of cempaka wood as the adsorbent. The results showed the characteristic of water content of biocharcoal was 4.05% while ash content was 7.75%. The optimum weight of biocharcoal to adsorb zinc ions was 40 mg with the adsorption capacity of 19.97 mg/g while for copper ions was 60 mg with the adsorption capacity of 16.16 mg/g. The optimum concentration of zinc and copper ions than can be adsorbed was 60 ppm with the adsorption capacity of 11.80 mg/g for copper ion and 9.29 mg/g for zinc ion

Harmonic reduction of a single-phase multilevel inverter using genetic algorithm and particle swarm optimization

Inverter play important role in power system especially with it capability on reducing system size and increase efficient. Recent research trend of power electronics system are focusing on multilevel inverter topic in optimization on voltage output, reduce total harmonics distortion, modulation technique and switching configuration. Standalone application multilevel inverter is high focused due to the rise of renewable energy policy all around the world. Hence, this research emphasis on identify best topology of multilevel inverter and optimize it among the diode-clamped, capacitor clamped and cascaded H-bridge multilevel inverter to be used for standalone application in term of total harmonics distortion and voltage boosting capability. The first part of research that is identify best topology multilevel inverter is applying sinusoidal pulse width modulation technique. The result shown cascade H-bridge give the best output in both total harmonics distortion (9.27%) and fundamental component voltage (240 Vrms). The research proceed with optimization with fundamental switching frequency method that is optimized harmonic stepped waveform modulation method. The selective harmonics elimination calculation have adapt with genetic algorithm and particle swarm optimization in order to speed up the calculation. Both bio-inspired algorithm is compared in term of total harmonic distortion and selected harmonics elimination for both equal and unequal sources. In overall result shown both algorithm have high accuracy in solving the non-linear equation. However, genetic algorithm shown better output quality in term of selected harmonics elimination where overall no exceeding 0.4%. Particle swarm optimization shows strength in finding best total harmonics distortion where in 7-level cascaded H-bridge multilevel inverter (m=0.8) show 6.8% only as compared to genetic algorithm. Simulation for 3-level, 5-level and 7-level for each multilevel inverter at different circumferences had been done in this research. The result draw out a conclusion where the possibility of having a filterless high efficient invert can be achieve

Evaluation of some Methods for Preparing Gliclazide-&#946-Cyclodextrin Inclusion Complexes

Purpose: Gliclazide has been found to form inclusion complexes with β- cyclodextrin (β-CD) in solution and in solid state. The present study was undertaken to determine a suitable method for scaling up gliclazide-β-CD inclusion complex formation and to evaluate the effect of some parameters on the efficiency of complexation. Method: The solid inclusion complexes of gliclazide and β-cyclodextrin were prepared at a molar ratio of 1:1 and 1:2 by mixing, kneading, and coprecipitation methods both on small and large scales. The effect of parameters such as kneading time and temperature on complexation was also studied. Characterization was performed using infrared spectroscopy, X-ray diffractometry, and dissolution studies. In vitro release studies were carried out in phosphate buffer (pH 6.8). Result: All the methods of preparation of complexes were found to be useful in increasing the solubility of gliclazide except mixing method where the rise in solubility was not significant. Both kneading and co-precipitation methods in 1:2 molar ratios were found to be equally effective in improving the solubility of gliclazide. The formation of inclusion complexes was evident in these formulations as shown by IR and XRD studies. But when carried out on a large scale, co-precipitation method was found to be more tedious and time-consuming than kneading method. Moreover percent recovery of complexes in the kneading method was found to be 98.76% as compared to 92.05% in case of co-precipitation method. Conclusion: Drug content studies, IR spectroscopic studies, X-Ray diffractometry studies and in vitro dissolution study data indicated that inclusion complexes prepared by kneading method in 1:2 molar ratios were suitable for improving the solubility of gliclazide. The same formulation was prepared at large scale and optimum formulation conditions were established. Keywords: Gliclazide, Inclusion complexes, β-cyclodextrin, Kneading Tropical Journal of Pharmaceutical Research Vol. 6 (4) 2007: pp. 833-84

Numerical studies of ion beam in NX2 plasma focus for different applied voltage

Plasma focus device gives simultaneous interaction between magnetic and electric field which results in exhibiting multi-radiation properties. Ion beam radiates from the system is significant for experimenting target material of interest in plasma focus research. Lee code model is used to simulate the numerical experiments on NX2-plasma focus device system using different applied voltage in the range 10 to 14 kV. The system is operating in Neon filled at an optimum pressure depending on the applied voltage used in the experiment. Results obtained are analysed and fitted with the experimental results for system validation. Good fitting on the numerical with the experimental results is obtained by incorporating mass shedding effects and current shedding factor. The range of current density obtained is in the range 1.6 × 108 to 7.3×109 Am-2whilst the maximum ion beam energy is estimated to be 156 J

Textile diamond dipoles for body centric communications at 2.45GHZ and 5.8GHZ

This study proposes textile diamond dipoles for body centric communication that operate at 2.45GHz and 5.8GHz. The proposed antennas have been rigorously tested under wearable and body centric measurements. Both substrates and conducting parts of the diamond dipoles are entirely made of textiles; which is deemed fit for wearable communications. Experiments such as bending, wetness and SAR were performed to investigate the antennas' performance for body communication realization. Bending was found not to cause any significant performance disruption. On the other hand, since the proposed antenna is not made of water-proof material, the performance was distorted under wet condition. However, once the antenna was dried out, the original performance was achieved. SAR measurement was also conducted and significant SAR values were observed when placing the proposed diamond dipoles close to human body

Elucidating the magma plumbing system of Ol Doinyo Lengai (Natron Rift, Tanzania) using satellite geodesy and numerical modeling

Ol Doinyo Lengai, located in the southern Eastern Branch of the East African Rift had several eruptive episodes with ash falls and lava flows (VEI 3) that caused damage to the nearby communities between 2007 and 2010. The volcano is remote and access is difficult. Although this volcano has been studied for decades, its plumbing system is still poorly understood, in part, because of the lack of precise observations of surface deformation during periods of quiet and unrest. This study investigates the volcanic plumbing system of Ol Doinyo Lengai and its surroundings using data from the network of permanent Global Navigation Satellite System (GNSS) sites monitoring the volcano (the TZVOLCANO network) around the flanks of the volcano and Interferometric Synthetic Aperture Radar (InSAR) observations. We constrain surface motions using 6 GNSS sites distributed around Ol Doinyo Lengai, operating between 2016 and 2021, and InSAR data covering nearly the same time period. Because of the complex local tectonics, the interpretation of the deformation pattern is not straightforward. We first invert the GNSS deformation and InSAR observations independently to infer potential deformation sources. Then we perform a joint inversion of both GNSS and InSAR datasets to verify our findings. We compare the results from the joint inversion with the results from inverting each dataset independently. The GNSS, InSAR, and joint inversion results point to a deflating source, located east of Ol Doinyo Lengai and southwest of the dormant volcano Gelai at a depth of 3.49 ± 0.03 km (GNSS inversion), 5.2 ± 1.2 km (InSAR inversion) and 3.49 ± 0.06 km (joint inversion) relative to the summit (vent) and with a volume change ΔV of -0.04 ± 0.05 × 106 m3 (GNSS inversion), -0.39 ± 0.29 × 106 m3 (InSAR inversion), and -0.04 ± 0.01 × 106 m3 (joint inversion). Although this is non-unique modeling of geodetic datasets with small signals, the inversion results suggest that Ol Doinyo Lengai could be fed by an offset multi-reservoir system that includes a shallow magma reservoir (<5 km) east of Ol Doinyo Lengai, possibly connected to a deeper magma reservoir

Penerapan Pembelajaran Aktif Berbasis Tugas Proyek untuk Meningkatkan Hasil Belajar IPA Siswa Kelas VII B SMP Kristen 2 Salatiga Tahun Pelajaran 2016/2017 Active Learning Application Based On Project Assignment In Improving Science Learning Results Of Stu

The purpose of this study is to find out the active learning application based on project assignment in improving science learning results of students in VII B class of SMP Kristen 2 Salatiga and to find out the improvement of the science learning results of students in VII B class of SMP Kristen 2 Salatiga throuh applying the active learning based on the project assignment. This study was done in SMP Kristen 2 Salatiga by using 21 students in this school as the subjects. The method applied in this study is the descriptive analysis method with the data collection instruments such as questionnaires, pbservation sheets and interview. The results of this study show that the active learning model based on the project assignment could improve students\u27 cognitive, psychomotor and affective learning results. Based on the students\u27 cognitive learning results, the students\u27 percentage fulfilling the minimum criteria (KKM) in cycle 1 is 66.67% and it improves into 90.47% in cycle 2. Based on the students\u27 psychomotor learning results, the students\u27 percentage fulfilling the minimum criteria (KKM) with a good criterion (≥ 25) in cycle 1 is 76.19% and it improves into 100% in cycle 2. Based on the students\u27 affective learning results, the students\u27 percentage fulfilling the minimum criteria (KKM) with a good criterion (≥ 25) in cycle 1 is 80.95% and it improves into 100% in cycle 2