The ASEAN Journal on Science and Technology for Development is the journal of the ASEAN Committee on Science and Technology (ASEAN COST). It reports on science and technology policies and programs and research activities undertaken by COST to support the social and economic development of ASEAN member countries. Third, the performance simulations were done in MATLAB using an algorithm written based on the engine-air duty cycle theory.
Both the experimental and simulation results show that there were no significant differences in the braking power and thermal efficiency of the engine between the use of diesel and B20 diesel. The performance characteristics of the engine using diesel and B20 were quantified by measuring fuel consumption and brake torque at various operating speeds. Fuel consumption (mf) was measured by recording the initial and current fuel volumes.
A theoretical model of engine performance was constructed based on the theory of engine operating cycles: intake, compression, combustion and expansion (Heywood 1988).
Developing a Generalized Combined Model for Gas-liquid Two-phase Flow Pressure Drop in
At this point, knowledge of the two-phase pressure drop in pipe components other than straight pipes is very important for accurate and reliable pipe design. Due to the two different velocities, the two different densities and the very complex phenomenon of the flow in the knees, the theory for the two-phase pressure drop of the flow in the knees is very rare. Therefore, estimating the pressure drop of the two-phase flow in knee bends numerically is not an easy task.
Even in single-phase flow, there is no exact solution for the pressure loss in elbow bends due to the complicated flow phenomena. Nowadays, a few researchers are trying to develop an empirical formula for a two-phase flow pressure drop in elbow bends based on experimental data.
Elbow Bends
In this section, three methods for calculating pressure drop in bends are presented, and one of them is proposed for two-phase flow. In this section, a generalized model for a two-phase flow pressure drop in elbow bends was proposed with reasonable considerations so that it could be used under a wide range of conditions. Basically, the two-phase flow pressure drop is strongly dependent on the phase fraction and the flow pattern.
The second problem was how to solve the pressure drop of the two-phase flow due to the elbow restriction. From this work, a general combined model was developed to predict the pressure drop of two-phase flow in elbow bends.
Ethanol Production in Yeasts Isolated from Fermented Kitchen Waste
The increased yield of ethanol production by microbial fermentation depends on the use of the ideal microbial strain, the appropriate fermentation substrate and the appropriate process technology. An ideal microorganism used for ethanol production should have fast fermentation potential, improved flocculation ability, significant osmotolerance, improved ethanol tolerance and good thermotolerance (Brooks 2008; Stewart et al. 1982; Yan & Tanaka 2006). Therefore, the objectives of this study were to isolate indigenous yeast strains from fermented kitchen waste and to evaluate their potential in ethanol production.
Ethanol production and glucose utilization were monitored by Fourier transform infrared attenuated total reflection (FTIR-ATR) spectroscopy. Ethanol and glucose levels in the samples were estimated based on the selected absorption wavenumber and absorbance values corresponding to the values of the chemical standards. Analysis of primary fermentation on yeast isolates from the other 5 groups detected different levels of ethanol.
Subsequent time-course studies of ethanol production were performed on isolates Y4, Y6 and Y8, representing groups 1, 2 and 3, respectively. These lead to an increase in hydrogen ion influx, which causes the decrease in transport rates, and eventually there was no further glucose uptake for ethanol production. FTIR spectroscopy offers fast and convenient methods to estimate the amounts of ethanol and glucose in the fermentation mixture.
A number of three promising ethanol-producing yeasts were isolated and partially identified from fermented kitchen waste. The highest ethanol production was achieved in yeast isolate Y4, which is believed to be closely related to Saccharomyces cerevisiae. Dombek, KM & Ingram, LO 1987, 'Ethanol production during batch fermentation with Saccharomyces cerevisiae: changes in glycolytic enzymes and internal pH', Applied and Environmental Microbiology, vol.
Chemical Composition of Leaf and Seed Oils of Dryobalanops aromatica Gaertn. (Dipterocarpaceae)
The methanolic extract of the wood has also been shown to have antifungal properties (Hong & Abdul Razak 1983; Kim et al. 2005). The percentage compositions of the oils were calculated based on the fresh weight of the respective plant parts. The relative percentage composition of the volatile compounds was calculated from the Total Ion Chromatogram (TIC), assuming that the relative response factor was equal to 1.
The seed oil contains 31 components representing 100% of the total oil, with the main components being α-pinene (41%), α-thujene and β-pinene (13% each), sabinene, limonene and bicyclomermacrene (6% each). , and myrcene (5%). These compounds are probably the most important volatile compounds that characterize the overall aroma of the two oils. Percentage composition and retention index (RI) of identified compounds in essential oils of fresh leaves and seeds of Dryobalanops aromatica Gaertn., in.
Percent composition and retention index (RI) of the compounds identified in the essential oils of fresh leaves and seeds of Dryobalanops aromatica. The previous attempt (Eaton 1925) on distillation of the leaves of this species reported that borneol was not obtained, but this study showed its presence in the leaf oil, albeit in a low amount (0.6%). Compounds such as camphene, terpineol and pinene, which have been reported to be present in the camphor and oleo-resin of the plant (Perry 1980; Duke & Ayensu 1985), were also found in this study.
In this study, the fatty acids and their derivatives were found only in the leaf oil and were represented by C6 compounds, mainly acids and alcohols, which constituted 1.4% of the oil. This study provides the complete chemical profiles of the essential oils obtained from the fresh leaves and seeds of D. In a literature review, it was found that many of the mixture viscosity models were developed for use in a homogeneous two-phase flow model.
Evaluation of Mixture Viscosity Models in the Prediction of Two-phase Flow Pressure Drops
Here, many averaging methods have been used to find the mixture properties (especially the mixture viscosity) that strongly influence the two-phase flow pressure drop. In previous work, viscosity models have only been studied for two-phase air-water flow and two-phase coolant flow in micro- and mini-channels. The aim of this work is therefore to investigate the influence of mixture viscosity models on the prediction of pressure drop for both liquid-liquid two-phase flow (oil-water) and gas-liquid two-phase flow (refrigerant, R134a) in circular tubes with micro, mini - and large diameter.
Predicted two-phase pressure drops were calculated using the homogeneous two-phase flow model with variation of the mixture viscosity models from equations 13 to 20. For liquid-liquid two-phase flow, the model of García et al. (2003) was the most suitable (especially for upward sloping flow) . Predicted and experimental frictional pressure gradients for two-phase oil-water flow at Um = 1.5 m/s, +10° slope (Angeli 2006).
It may be noted that Davidson et al.'s (1943) model was not well suited for predicting the two-phase flow of gas and liquid because it had a very high error term. Therefore, Group II viscosity models (except Owen (1975) model) are less preferred for predicting pressure drop in two-phase gas-liquid flows. The εrms values of each viscosity model in predicting two-phase gas-liquid flows are shown in Table 5.
Thus, this study investigated the effectiveness of existing mixture viscosity models in two-phase flow pressure drop prediction. Friction pressure drop of oil-water flow and two-phase flow of refrigerant (R134a) in micro-, mini-, and large-diameter pipes were predicted using the homogeneous variational mixture viscosity model. Except for Owen's model, Group II mixture viscosity models are not suitable for predicting pressure drop in gas-liquid two-phase flow.
Utilization of Agricultural Wastes in the Manufacture of Composite Boards
It is an important source of income for small farmers, who make up 80% of banana growers (Rivera 2004). In order to determine the various characteristics of the manufactured samples, the following tests and analyzes were carried out. Internal bond is a mechanical property of materials that refers to the tensile strength perpendicular to the plane of the plate.
To compare parameters MOR, IB, FSHT/NPHT, thickness swelling and water absorption; the statistical tool used was the one-tailed t-test, considering the equivalence of the mean value or the non-equivalence of the standard value, the upper and lower limits of the tailed t-test were considered according to the PNS value. RESULTS AND DISCUSSION The observed physical properties of the three different panels were not significantly different. The color of the raw materials was visible in the banana peel and peanut shell panels, as the binder used was colorless.
The different colors of the plastic strips in the cornhusk board dominate, although the husk strips are also observed. The average density of the peanut shell plate samples subjected to the various tests was 0.0.6565 g/cc with a p-value of 0 for the upper limit tail t-test for the lower standard value of 0.4 g/cc and p -value of 0 for the lower bound tail t-test. The average water absorption obtained was 72.05% with a p-value of 0.002 for the upper limit with tailed t-test, indicating a probability of the value greater than 30%, an indication of non-conformity with PNS.
The board's WA was quite high compared to the maximum standard value of 30%; in contrast to the TS result, where the maximum value was 20%. The IB statistical evaluation obtained a p-value of 0.305 to check whether the average value is equivalence with the value of the minimum value of the standard. Reducing the individual fiber length of the banana sheath can also increase the internal bond strength of the banana sheath plate.
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