Single cell and multiple cell clouds analysed with satellite data in and around Bangladesh

Multi-cell and single-cell clouds were analysed using Geostationary Meteorological Satellite (GMS-5) data on 6 and 13 August 1997 in and around Bangladesh. The multi-cell cloud moved NE with a speed of about 6 m/s and lasted approximately 21 hours. The single-cell cloud moved SE with a speed of about 13 m/s and lasted approximately 12 hours. Clouds move faster on oceans than on land. At the mature stage of the cloud, convective component was 40% and the rest was stratiform. The precipitable portion of the cloud was 74% and the rest was non-precipitable which differs from the reported value.

Evaluation of Relations between Extreme Precipitation and Temperature in Observational Time Series from the Czech Republic

The intensity of precipitation extremes is expected to increase as the climate warms and it may cause floods and increase erosion. From the Clausius-Clapeyron relation (CC) it follows that the maximum moisture content of the atmosphere increases by approximately 7% per degree as temperature rises. However, the increases in observed hourly precipitation extremes of approximately two times the CC relation were described recently. This super CC scaling is attributed to the increased prevalence of convective rainfall and decreased prevalence of stratiform rainfall as temperatures increase. We carried out the disaggregation of precipitation into prevailing stratiform and convective component on the observational data from the Czech Republic for 1966–2006. Then, we analyzed trends in characteristics of disaggregated events and assessed correlation of precipitation intensities with daily mean temperature. The results suggest the increasing trend of convective precipitation in summer. The scaling for total rain events is steeper than for the events with prevailing convective component and for the events with prevailing stratiform component. It is a result of mixing of the two storm types. At higher temperature the events with prevailing convective component prevail and vice versa.

MATHEMATICAL MODEL OF THE THERMAL-AIR REGIME OF A VENTILATED ATTIC

This paper presents the developed mathematical models that characterize the thermal-air regime of a ventilated attic in the summer and winter seasons. The relevance of the mathematical models was shown and examples of applying these models to solve some engineering problems were presented. Mathematical models can be used to analyze and evaluate changes in the temperature and heat flux (the radiant and convective component) along the air movement in the attic and to select the materials for the roof and floor, as well as for the calculation of ventilation for different climatic conditions.

An Experimental Investigation of Throughflow Velocities in Two-Dimensional Fluidized Bed Bubbles: Laser Doppler Anemometer Measurements

Detailed nonintrusive measurements have been made to determine the throughflow velocity in isolated fluidized bed bubbles. In air-fluidized beds, the throughflow component has been rather neglected and measurements of the visible bubble flow alone have, therefore, failed to clarify the overall distribution of gas flow between the phases. A single component fiber optic laser Doppler anemometer was used to map the fluid flow through a bubble rising in a two-dimensional bed. The bed was fluidized at a superficial velocity slightly higher than incipient. The conditioned sampling technique developed to characterize the periodic nature of the bubble phase flow revealed that the throughflow velocity in two-dimensional beds increases linearly with increasing distance from the distributor, thereby enhancing the convective component in the interphase mass transfer process. Bubble growth was accounted for and the end-effects were minimized. Dependence of the bubble throughflow on the elongation of the bubble was observed thus confirming the theoretical analysis of some previous investigators. However, experimental evidence presented in this paper showed that the existing models fail to accurately predict the convective component in the bubble phase of two-dimensional fluidized beds.

Mechanism of afterdrop after cold water immersion

It was hypothesized that if afterdrop is a purely conductive phenomenon, the afterdrop during rewarming should proceed initially at a rate equal to the rate of cooling. Eight male subjects were cooled on three occasions in 22 degrees C water and rewarmed once by each of three procedures: spontaneous shivering, inhalation of heated (45 degrees C) and humidified air, and immersion up to the neck in 40 degrees C water. Deep body temperature was recorded at three sites: esophagus, auditory canal, and rectum. During spontaneous and inhalation rewarming, there were no significant differences between the cooling (final 30 min) and afterdrop (initial 10 min) rates as calculated for each deep body temperature site, thus supporting the hypothesis. During rapid rewarming, the afterdrop rate was significantly greater than during the preceding cooling, suggesting a convective component contributing to the increased rate of fall. The rapid reversal of the afterdrop also indicates that a convective component contributes to the rewarming process as well.

Convective Characteristics of Pediatric Peritoneal Dialysis

The convective aspects of pediatric peritoneal dialysis (PD) -fluid transfer with its attendant solvent drag -were evaluated in vivo in 8 children on maintenance PD. The evaluation was performed according to the mass transport model of pyle. Reflection coefficients were calculated for urea, creatinine, uric acid, glucose and idealized total protein. These values were compared to adult means. There were no differences in reflection coefficients, except for total protein, which had a lower value. Maximum ultrafiltration rates were also calculated for the three commercially avail able dialysate glucose concentrations (1.5%, 2.5%, 4.25%). These values were scaled for body surface area to allow comparison with adult means. All values were lower than the adult means, but were not outside two standard deviations. Convective transport in PD in children over 1 Vl years of age, does not appear to be significantly different than that in adults. There are two components to solute removal in peritoneal dialysis: diffusion and convection. Convective transport, the passive movement of solute in a solvent stream across a semipernleable membrane, is directly related to the rate of ultrafiltration. The convective component of solute removal in peritoneal dialysis may be responsible for a significant per cent of transport of larger molecular weight solutes (I). Little infornlation is currently available concerning this aspect of pediatric peritoneal dialysis. Kohaut and Alexander have reported that it is more difficult to achieve ultrafiltration in infants than in older children, adolescents, and adults (2). The convective component of peritoneal dialysis in infants may therefore contribute less to overall solute removal than in older children and adults.