The transient hydrodynamics and thermal behaviors of fluid flow in an openended vertical parallel-plate microchannel are investigated analytically under the effect of the hyperbolic heat conduction model. The model that combines both the continuum approach and the possibility of slip at the boundary is adopted in this study. The effects of Knudsen number Kn and thermal relaxation time τ on the microchannel hydrodynamics and thermal behaviors are investigated using the hyperbolic and the parabolic heat conduction models. It is found that as Kn increases, the slip in the hydrodynamic and thermal boundary condition increases. Also, this slip increases as τ decreases.KEY WORDS: free convection; hyperbolic heat conduction; macroscopioc heat conduction models in microchannel; vertical microchannel; microchannel thermal and hydrodynamic behavior.

Detachment of soil particles by the processes of splash from rainfall and shallow flow from surface runoff is influenced by soil cohesion, soil aggregate properties, and characteristics of this flow. We have evaluated relationships between rates of detachment, aggregate size, and tensile strength of the soil. Soil and water losses were determined in the laboratory from sieved air-dry samples on three aggregate size ranges of two clay loam soils differing in particle-size distribution and organic matter. Tensile strength was measured for each aggregate size range. The results showed that as clod size increased, detachment rates increased and interaggregate tensile strength decreased. Wash erosion increased as initial clod size increased despite a decrease in runoff. Final rates of loss by splash were greater from the largest clods than from the smaller clods. Finally, splashed material was larger in size than material washed off. The fact that the size of the splashed material was larger than washed-off material shows that material in the wash suffered more impact by raindrops and thus was more likely to be fragmented.

No abstract

Detachment of soil particles by the processes of splash from rainfall and shallow flow from surface runoff is influenced by soil cohesion, soil aggregate properties, and characteristics of this flow. We have evaluated relationships between rates of detachment, aggregate size, and tensile strength of the soil. Soil and water losses were determined in the laboratory from sieved air-dry samples on three aggregate size ranges of two clay loam soils differing in particle-size distribution and organic matter. Tensile strength was measured for each aggregate size range. The results showed that as clod size increased, detachment rates increased and interaggregate tensile strength decreased. Wash erosion increased as initial clod size increased despite a decrease in runoff. Final rates of loss by splash were greater from the largest clods than from the smaller clods. Finally, splashed material was larger in size than material washed off. The fact that the size of the splashed material was larger than washed-off material shows that material in the wash suffered more impact by raindrops and thus was more likely to be fragmented.

Both a cold and hot water supplies in Jordan are provided by indirect systems and so is the fuel supply for central heating, by using storage tanks placed over the buildings roofs. This requires climbing to the roofs for measuring the level of fluid in these tanks. This method is primitive, impractical and tedious. A simple reliable easing system is designed, manufactured and tested for solving the existing problems associated with the already used method. The equipment measures the level of cold water and fuel and also allows the measurement of the temperature of the hot water and displays them on a board inside the user's house with an accuracy of 2 - 3 %, which is acceptable in such applications. However, when the measurement is taken for payment purpose the fuel level should be measured exactly. Also the system indicates when the water arrives from the main supply. The described equipment is small in size and weight and of low power consumption; in addition it requires minimum maintenance, which makes it cost effective. However the model needs testing in freezing point of used liquids. Also the device requires further development in order to solve other problems facing building services in Jordan