Heat transfer , condensation and fog formation in crossflow plastic heat exchangers
-In this paper heat transfer of air-water-vapour mixtures in plastic crossflow heat exchangers is studied theoretically and experimentally. First, a model for heat transfer without condensation is derived, resulting in a set of classical differential equations. Subsequently, heat transfer with wall condensation and fog formation are considered in some detail. Separate attention is paid to the heat transfer and condensation of pure steam in the heat exchanger. Finally, the experiments performed are reported and the results compared with the models presented. From this comparison it can be learnt that the models are well able to predict the rate of heat transfer and phenomena such as condensation and fog formation.
Heat transfer and condensation of water vapour from humid air in compact heat exchangers
In this thesis, an experimental and simulation study of heat transfer in water-to-air 
compact-plate heat exchanger is presented. A compact-plate heat exchanger made of 
polypropylene, in which flow pattern is maintained as counter-current, was 
constructed to conduct the experiments. Experiments were conducted for different 
operation conditions of hot and cold fluids, in which hot water is considered hot 
streams and air is considered cold streams. The thermal performance of the plate heat 
exchanger was analysed using the experimental data. Computational fluid dynamics 
(CFD) package FLUENT® was used to predict the fluid flow and heat transfer in the 
plate heat exchanger and to study the transient response of the system to changes of 
inlet temperature for both fluids. The results of the heat rejection rate are presented 
for the heat exchanger, which is simulated according to the configuration of the plate 
heat exchanger used in the experiments. The model was also simulated at different 
operation conditions and compared with experimental data. The simulated results are 
in good agreement with experimental results.
Silica in Soils1
Publisher Summary Silica in free and combined forms is a dominant component of the solid material of many soils, and dissolved silica is commonly a major solute of soil solutions. Breakdown of primary silicates, translocation of silica in solution, and deposition of secondary silica-containing substances are involved in the development of soils. Ions essential for the growth of plants are released to the soil solution as silicates weather, and these ions may be held against leaching at exchange sites on other silicates. Silica is absorbed in appreciable quantities by some plants and is returned to the surface of the soil as the plants decay. The nature and transformations of silica and silicates in soil are, thus, fundamental to an understanding of many aspects of soil and plant sciences.