Search

This paper presents experimental results on rapid freezing of water droplets injected into a low temperature environment. A heat balance method was applied to determine the ratio of the water droplets frozen at the collection after the airborne time. The experimental results show that rapid freezing of water droplets could be achieved within three seconds of airborne time. Droplet size distribution of the frozen water droplets after collection was estimated. Heat transfer during the airborne time was calculated with consideration of the droplet size distribution. At attempt was taken to compare the heat transfer obtained with some previous studies on heat transfer of spherical objects in air. The research results show that droplet size distribution is important for the prediction of heat transfer of water droplets traveling in air. The results presented in this study contribute to the understanding of heat transfer of water droplets injected into a low temperature air.

This study uses a novel concept of capacity coupling of chiller-cooling tower system to investigate the system energy performance. System performance factor (SPF) of the chiller-cooling tower system is used in the analysis. A regression function is obtained for hourly reset of condensing water temperature so to achieve maximum SPF. The regression function includes parameters such as ambient wet bulb temperature, chiller load ratio, tower capacity ratio, and a dimensionless relative efficiency of chiller and cooling tower. The regression function has an R2 close to 1 compared to the computed results. It is found that for capacity coupling ratio of 1.1 ∼ 1.6, SPF would increase by about 3 ∼ 6% compared with a typical base control. The effect of wet air return is presented as an equivalent wet bulb temperature. It has been found that SPF would decrease significantly when higher equivalent wet bulb temperature occurs at the tower inlet.

Interleukin-27 (IL-27) has a pleiotropic role either as a pro-inflammatory or anti-inflammatory cytokine in inflammatory related diseases. The role and involvement of IL-27 during malaria was investigated and the effects of modulating its release on the production of major inflammatory cytokines and the histopathological consequences in major affected organs during the infection were evaluated. Results showed that IL-27 concentration was significantly elevated throughout the infection but no positive correlation with the parasitaemia development observed. Augmentation of IL-27 significantly elevated the release of anti-inflammatory cytokine, IL-10 whereas antagonising and neutralising IL-27 produced the opposite. A significant elevation of pro-inflammatory cytokines (IFN-γ and IL-6) was also observed, both during augmentation and inhibition of IL-27. Thus, it is suggested that IL-27 exerts an anti-inflammatory activity in the Th1 type response by signalling the production of IL-10 during malaria. Histopathological examination showed sequestration of PRBC in the microvasculature of major organs in malarial mice. Other significant histopathological changes include hyperplasia and hypertrophy of the Kupffer cells in the liver, hyaline membrane formation in lung tissue, enlargement of the white and red pulp followed by the disappearance of germinal centre of the spleen, and tubular vacuolation of the kidney tissues. In conclusion, it is suggested that IL-27 may possibly acts as an anti-inflammatory cytokine during the infection. Modulation of its release produced a positive impact on inflammatory cytokine production during the infection, suggesting its potential in malaria immunotherapy, in which the host may benefit from its inhibition.

This study investigates experimentally the performance of radiant floor cooling modules. Different radiant cooling modular units with embedded chilled water piping were tested for cooling performance. The effects of pipe pitch and also the effects of extended fins were tested. The results of the experiments show that the modular design of radiant floor used has low heat resistance between the chilled water and the radiant cooling surface. Mean radiant temperature was analyzed to measure the cooling comfort performance. An increase of radiant cooling surface area was found to be important for effective radiant heat exchange. Moreover, the larger the temperature difference between the radiant surface and the walls, higher rate of radiant cooling can be achieved. The cooling intensity in terms of per unit area was tested to be as high as 60 W/m2. In conclusion the radiant floor cooling modular units are effective to remove sensible heat and provide comfort cooling. In practice it can be supplemented with lower humidity outdoor air supply for the removal of latent heat.