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

Design and development of micro direct methanol fuel cell (μDMFC) for portable application

A passive, air-breathing single cell and a multi-cell stack micro direct methanol fuel cell with 1.0 cm2 active area were designed, fabricated and tested. The fuel cell was completely passive without any ancillary device such as pump. Oxygen was taken from the surrounding air, and the methanol solution was stored in a built-in reservoir. The performance of the single cell was tested with different methanol concentrations ranging from 1.0 M to 5.0 M, and the optimum performance was achieved by using methanol at a concentration of 4.0 M. A stack with 6 cells was fabricated and tested with the optimum methanol concentration of 4.0 M, and power levels produced by different catalyst loadings on the anode were compared. The combination of a catalyst loading of 3.0 mg cm-2 Pt/Ru on the anode and 2.0 mg cm-2 Pt on the cathode yielded the highest power of 12.05 mW at 1.08 V and 11.2 mA

Abstraction and Generalization in Conceptual Design Process: Involving Safety Principles in TRIZ-SDA Environment

Abstraction and generalization are the processes of facilitating a specific problem to help designers solve problems efficiently. Abstraction and generalization reduce complexity and increase creativity. Both abstraction and generalization guide designers to focus on the key factors of a problem towards producing a broader solution perspective. This paper aims to discuss the use of abstraction and generalization in the conceptual design process within the Theory of Inventive Problem Solving (TRIZ) environment, specifically, in TRIZ-SDA (Systematic Design Approach), which was developed to increase the understanding of safety principles in the conceptual design process. In addition, the aspects of abstraction and generalization advantages, their implementation in the design process, safety constraints and comparisons between abstraction and generalization are also reviewed. A case study of an aircraft component is used as the example in conducting abstraction and generalization in the safety approach

Training needs assessment in Malaysia: Exercise held at Kuala Lampur and Kota Bharu from 13th October 1989

Training / Irrigation / Evaluation / Malaysia

Nutritional enhancement of total lipid, n-3 and n-6 fatty acids in Artemia urmiana nauplii by enriching with ICES/30/4

Artemia urmiana nauplii were enriched with three different concentrations (100, 200 and 300 ppm) of commercial emulsion, ICES/30/4 during two periods (12 and 24 h) to evaluate the enhancement of its Highly Unsaturated Fatty Acids (HUFAs). This source was selected because of its high concentration of the longest chain HUFA's in the n-3 and n-6 series. When 24-h-old Artemia nauplii were enriched with 100 ppm concentration of ICES30/4 during 12 h enriching period, the docosahexanoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA) contents of the nauplii increased to 0.77, 1.22 and 0.34 and when enriched with 300 ppm during 24 h increased to 5.99, 4.97 and 0.73 mg g(-1) dry weight, respectively. DHA, EPA and ARA in control nauplii were 0.00, 0.82 and 0.61 mg g(-1) dryweight, respectively. Total lipid increased from 16.79% in control group to 20.87% in the treatment ICES30/4 24-300. The results suggest that high amount of emulsion and prolong the enriching period are effective in enriching Artemia nauplii in both DHA and EPA increasingly (p < 0.05) but in other fatty acids, there are differences only among period treatments (p < 0.05) and concentration are not any increasing effective. There are only differences among concentration treatments in total lipid p < 0.05) and enriching period do not show any differences

Low sidelobe and wideband characteristics of density tapered arrays for 5G mobile systems

Conventional mobile base station antennas are composed of equally spaced linear array antennas. In order to achieve low side lobe characteristics, excitation coefficients for array elements are determined by a feeding network. Because of complexity of the feeding network, applicable frequency range is limited. In 5G mobile system, multi frequency band operation is requested. For achieving low sidelobe and wide frequency characteristics, a density tapered array configuration is promising. Because of uniform excitation coefficients, feed network has no frequency dependence and wide frequency range application is expected. In this paper, abilities and design method of low sidelobe characteristics are investigated. By density tapering, sidelobe levels are reduced from-13dB to -16dB. As for wide band characteristics, low sidelobe characteristics are maintained during 28GHz to 56GHz operations. Usefulness of a density tapered array is numerically clarified

Bioavailability of heavy metals (Zn, Cu, Pb and Fe) in surface sediments of the Malacca River, Malaysia

Untreated chemical wastes from industrial and domestic areas could be the point sources of the metal contamination in the surface sediments of the Malacca River. Four different sampling sites along the Malacca River were chosen due to the nearby industrial and urban activities. The aqua-regia method and the sequential extraction technique were used to extract total- and bioavailable-concentration of heavy metals in the sediments. Concentrations of heavy metals were determined by an Atomic-Absorption Spectrophotometry (AAS). Results of heavy metals in the sediments showed that the mean concentration of Cu (367.8 μg/g) exceeded the Sediment Quality Guidelines (SQGs), thus potentially being able to affect the benthic macro-fauna adversely. The concentration of Zn (152.9 μg/g) and Pb (22.52 μg/g) were lower than Interim Sediment Quality Guidelines (Low). Geofractionation of the metals in the sediments showed that the Cu in sediments from anthropogenic sources had more than 93% bioavailability ([oxidisable-organic]>[exchangeable]>[acid-reducible]).In contrast, Zn, Pb and Fe were dominantly in the form of the lithogenic fraction by 55.4%, 97.4% and 93.8%, respectively with order of extraction [residual] > [oxidisable-organic] > [acid reducible] > [exchangeable] fraction

Relationship between body mass index, waist circumference, fat mass and fat percentage as a measurement of obesity among Universiti Pendidikan Sultan Idris students

The purpose of the study was to determine the prevalence of obesity based on the Body Mass Index (BMI), waist circumference, and fat mass and fat percentage and to examine the relationship between BMI, waist circumference, fat mass and fat percentage as the measurement of obesity among university students. The participants were 305 students from Univesiti Pendidikan Sultan Idris (UPSI) aged between 18-25 years old with males (n =101) and females (n =204). Digital InBody Stadiometer was used to measure height. Body Composition Analyzer was used to determine body mass, fat percentage, fat mass and body mass index. Seca - SC100 tapes was used to measure waist circumference. The data was analysed using descriptive statistic to determine the prevalence of obesity and the Pearson correlation was used to determine the relationship between the variables being studied. Results showed that the prevalence of obesity based on BMI in male was 34.6. % overweight and 12.9 % obese and 31% was overweight and 12% obese among female participants.  The prevalence of obesity according to BMI was higher in men if compare to women. The results of waist circumference showed the greater number of females (71.6%) being overweight compared to males (64.3 %). Overall, there was a strong, positive correlation between body mass index, waist circumference, fat mass and fat percentage in measuring obesity.Keywords: Overweight, Obese, BMI, Waist circumference, and Fat mas