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Year 2011

Volume 2, Issue 4 October - December 2011

Abstract: Fermentation is a process by which large organic molecules are broken down in to simpler molecules as the result of the activity of microorganisms. Bioethanol is produced by the activity of some bacteria, and yeast, and their actions on substrates containing carbohydrates. Biofuels are a wide range of fuels that are in some way derived from biomass. Biofuels are gaining increased public and scientific attention, due to factors such as oil price spikes and the need for increased energy security.
It was observed that nutrients play a vital role in the process of fermentation. During the present study, seven bacteria were isolated from rotten fruits, out of which four bacteria (A, B, X and Y) all bacteria were gram positive and rod-shaped. They were able to ferment carbohydrate and produce bioethanol. The different substrates barley, oat, maize and sugar beet were used for bioethanol production. During the present investigation, the effects of different macro- and micro-nutrients on bioethanol production were also assessed.
It was observed that after supplementation of 5 ml and 10 ml of macronutrients (carbon, nitrogen, sulfur and phosphorus) in all four substrate solutions (barley, oat, maize and sugar beet), the barley had produced the most bioethanol. Thus, it was observed that macronutrients had a relevant effect on bioethanol production. On the contrary, large amounts of production were not seen when micronutrients (aluminum, copper, chromium and zinc) were added in pure form.

Key words: Bioethanol, Fermentation, Macronutrient, Micronutrient and Bacteria.
(91 K)
Abstract: At present, the arrival of a 1020 hPa isobar at the border of Thailand is assumed to define a strong high pressure area over the country associated with a cold surge. Using this definition, with the National Centers for Environmental Prediction (NCEP) analysis data, twenty-four strong high pressure cases were found in the five winters (October-February) from 2002 to 2006. The 24 cases were studied using the Advanced Research WRF (ARW) Modeling System in order to determine the extent to which they were cold surges as defined by a mean sea level pressure (MSLP) rise, a sudden increase in wind speed, and sharp drops in surface air temperature and dew point temperature. The 24-hour changes of meteorological elements for five days at Udon Thani station during the strong high pressure cases were examined to find detailed criteria for forecasting cold surges in Thailand. It was found that the indicators of a cold surge are an increase in wind speed of at least 2.6 m/s, a rise in MSLP of at least 1.8 hPa and drops in surface air temperature and dew point temperature of at least 1.7°C and 2.1°C, respectively, at Udon Thani station.

Keywords: Cold surge, strong high pressure area, winter monsoon.
(710 K)
Abstract: Renewable energy technologies contribute to the mitigation of climate change impacts through reduction in the emission of greenhouse gases (GHG) such as carbon dioxide. In this paper, a power plant located in Italy and fed with waste deriving from the olive oil industries is considered. The de-oiled pomace is characterised by lower caloric value equal to 4000 kcal/kg, by low content of nitrogen and sulphur and by the absence of heavy metals. A plant for the production of energy from biomass (de-oiled pomace and waste wood) is analyzed through a Life Cycle Assessment (LCA) approach. The carbon dioxide equivalent (kgCO2eq) emitted into the atmosphere is equal to 0.0597 kgCO2eq /kWh. The GHG emissions have been compared with those of a plant for energy production that uses refuse derived fuel (RDF) and with those of one that uses coal. The environmental benefits are quantified and the possibilities to develop the use of the pomace-to-energy at national level are estimated.

Keywords: LCA, Biomass, GHG balance, Bioenergy, Carbon footprint.
(417 K)
Abstract: Nuclear power is a promising approach to sustaining energy security and saving the global environment from the global warming crisis. Thailand also considers initiating the first nuclear power plant preparations. Several activities, including policy strategy and action plan development are being carefully processed to handle this challenging project for which several shortcomings, such as public acceptance, nuclear safety, project transparency, policy instability etc., have to be overcome. Public acceptance is the most difficult for project implementation. One of the most interesting solutions is to educate people about the impact as well as the management approaches of the project for mitigating any negative consequences. In this study, the impacts of a nuclear power project are investigated and identified, and impact management approaches are also suggested.

Keywords: Energy Policy, Nuclear energy, Social Impact Management, Nuclear Power Project management
(396 K)
Abstract: This paper describes a computer-based thermodynamic model that evaluates the performance of hydrocarbon (HC) mixtures as alternative refrigerants to conventional synthetic refrigerants. By estimating the refrigeration effect, compressor work, and coefficient of performance, the analytical tool helps to optimize the system’s design to suit a particular HC mixture or to identify the best HC mixture to be used as a drop-in refrigerant for an existing conventional system. The model is validated against experimental data that compared the performance of liquefied petroleum gas (LPG) to that of refrigerant R12 for domestic refrigeration. The results obtained show that the model correctly predicts the differences observed in the experiment. In agreement with the experimental data, the model's estimates show an improved performance for LPG compared to R12.

Keywords: Global warming, hydrocarbon refrigerants, natural refrigerants, ozone-layer depletion, thermodynamic model.
(175 K)
Abstract: The objective of this research was to investigate in-kitchen air quality as related to stove utilization during cooking. The experiment was conducted at Way Isem, a village located in the North of Lampung Province, Indonesia. Nine homes using four different fuels or stoves participated in this experiment with a total of fifteen samples - five wood stoves, five kerosene stoves, four liquefied petroleum gas (LPG) stoves and one biogas stove. In-kitchen air quality was measured using five parameters, namely SO2, NO2, dust, PM10 and opacity. In-kitchen air was sampled using a High Volume Air Sampler apparatus equipped with a vacuum pump. The air was then absorbed using a RAC 5 gas sampler for further analysis. Results showed that SO2 content in the kitchen air for an hour of measurement ranged from 340 to 357 μg/Nm3, lower than the Indonesia standard of 900 μg/Nm3. NO2 content, ranged from 12 to 19 μg/Nm3, was also distinctly lower than the national standard of 400 μg/Nm3. Wood stoves, however, resulted in high concentrations of dust and PM10, which were 390 μg/Nm3 and 400 μg/Nm3, respectively. These numbers were higher than the national standards of 230 μg/Nm3 for dust and 150 μg/Nm3 for PM10.

Keywords: Biomass, black carbon, gas emission, indoor cooking, in-kitchen air, opacity, particulate matter, stove.
(287 K)
Abstract: Mathematical models of indirect internal reforming solid oxide fuel cells (IIR-SOFC) fueled by natural gas were developed to analyze the thermal coupling of an internal reformer with electrochemical reactions and to investigate the system performance. The models are based on steady-state, heterogeneous, two-dimensional reformer and annular design SOFC models. The configuration of the internal reformer was considered as conventional packed-bed reactor. The simulations indicated that natural gas is rapidly consumed at the reformer; hence, it appears that the temperature is drops substantially at the entrance of the reformer. It is also observed that the composition of natural gas also plays an important role on the IIR-SOFC thermal and electrical performance. Natural gas from the Gulf of Thailand, after processing, has a lower hydrocarbon content and provides a smoother temperature gradient along the SOFC system, but achieves lower power density and electrical efficiency when compared with natural gas from the North Sea.

Keywords: SOFC; internal reforming; natural gas.
(820 K)

ISSN: 1906-4918
Frequency: Quartery
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