Reduction of heat accumulated in a thermosyphon paddy bulk storage

The objective of this research work was to develop a thermosyphon paddy bulk storage for reducing heat accumulated due to paddy respiration. A prototype of thermosyphon paddy bulk storage and a mathematical model with lumped analysis for predicting the paddy bed temperature were conducted. The storage was a double-wall steel cylinder with 636 mm outside diameter and 1500 mm length. The evaporator section consisted of a set of 70 copper tubes with 3.0 m² surface area. The condenser section is the upper body of the storage tank and was ventilated with controlled air. In this study, the paddy bed, the ambient air, and methanol were used as the heat source, heat sink and working fluid in the thermosyphon, respectively.

The paddy bulk of 115 kg with 12.5% wet basis was placed in the evaporator section of the thermosyphon. From the experiment it was found that the paddy bed temperature could be reduced from 31–32 to 26–27°C within 15–20 hours. Moreover the actual overall heat transfer coefficient between the bed and the working fluid was evaluated to be about 4.3 W/m²°C. The paddy bed temperature could be maintained at about 26–27°C for eight weeks and the paddy qualities, whiteness and head yield, were in very good condition. In addition, the mathematical model developed could be used to predict the paddy bed temperature accurately.     

Kinetic of myristic acid esterification with methanol in the presence of triglycerides over sulfated zirconia

The esterification of myristic acid with methanol in presence of triglycerides using sulfated zirconia prepared by solvent-free method as the heterogeneous catalyst was studied. The effects of reaction temperature (393–443 K), catalyst loading (1–3 %wt) and molar ratio of oil to methanol (1:4–1:20) on the conversion of myristic acid were investigated. The experimental data was interpreted with a second order pseudo-homogeneous kinetic model. The kinetic parameters were obtained. A good agreement between the experimental data and the model was observed. Sulfated zirconia prepared by solvent-free method exhibited high catalytic activity for this reaction. Low activation energy of 22.51 kJ mol^?1 was obtained in the range of temperature of 393–443 K.     

Simultaneous Conversion of Triglyceride/Free Fatty Acid Mixtures into Biodiesel Using Sulfated Zirconia

Simultaneous transesterification and esterification of rapeseed oil with methanol in the presence of myristic acid was investigated. The effect of reaction temperature (120, 150 and 170 °C) and the effect of initial free fatty acid content in oil (0, 10 and 20 wt%) on reaction rate were studied. The catalysts were found to increase the rate of all reactions. Sulfated zirconia prepared by a solvent-free method exhibited higher activity in simultaneous reaction than the conventional method. The presence of 10 wt% free fatty acids in the triglyceride increased the reaction rate and the final total fatty acid methyl esters content, and suggests that a “non-catalytic” reaction may be feasible.     

Integration of the component of financial statement in highway maintenance planning

Highway agencies attempt to apply efficient accounting systems to help improve the transparency of their budget allocation and their overall performance. The accrual accounting system has been adopted to substitute the cash accounting system by many central governments around the world. The system reports transactions of economic value changes rather than when cash movements are made. The asset value and its depreciation determined by the accrual accounting system illustrate the total amount of economic value owned by an agency and the consumption of the future economic benefits for an asset. The age‐based depreciation approach, which is a traditional approach, is applied to determine the depreciation of an asset based on the defined useful life and the straight‐line depreciation method. The advantage of this approach is its simplicity and its ability to support the long‐term asset management system. The condition‐based depreciation is recommended as an alternative approach since the actual condition of an asset can reflect its depreciation. The depreciation of an asset based on the condition‐based approach is suitable for single‐year maintenance planning since the executives cannot estimate the required budget for replacing or preserving of an asset in the long‐term period. This research focuses on developing the new depreciation approach by integrating the age‐based and the condition‐based depreciation approaches in order to strategically plan long‐term highway maintenance and to enable the actual condition of an asset to be reflected.