Heat transfer and fluid flow in microchannels have been topics of intense research in the past decade. A critical review of the current state of research is presented with a focus on the future research needs. After providing a brief introduction, the paper addresses six topics related to transport phenomena in microchannels: single-phase gas flow, enhancement in single-phase liquid flow and fl...

This paper aims to perform the second law analysis of thermodynamics on the laminar film condensation of pure saturated vapor flowing in the direction of gravity on an ellipsoid with variable wall temperature. The analysis provides us understanding how the geometric parameterellipticity and non-isothermal wall temperature variation amplitude “A.” affect entropy generation during film-wise conde...

Lewis acidic zeolites are used to synthesize unsaturated dicarboxylic acid esters via aldol condensation of keto esters. Hafnium-containing BEA (Hf-BEA) zeolites catalyze the condensation of ethyl pyruvate into diethyl 2methyl-4-oxopent-2-enedioate and diethyl 2-methylene-4oxopentanedioate (an itaconic acid ester analogue) with a selectivity of ca. 80% at ca. 60% conversion in a packed-bed reac...

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-In this paper, the transient forced convective condensing flow of a gas through a packed bed is analyzed. The model developed for this analysis does not employ any local thermal equilibrium assumption between the solid and the fluid phases. Inertial as well as viscous effects are considered in the vapor phase momentum equation by using the Ergun-Forchheimer relation. Thermal charging of the pa...

A mathematical model for the formation of condensation aerosols from highly supersaturated vapor-air mixtures is presented. The suitable systems with very high nucleation rates that result in aerosol mass densities >1 g/m3. It accounts nucleation, non-isothermal condensation, coagulation and indirectly coalescence newly formed particles. applies kinetic theory to determine rate treats separate ...

In the energy-saving research developments in recent years, many types of research project on high performance heat pump systems are under development It is required to estimate the thermodynamic performance of these thermal cycles on a common scale by applying an adequate method. a basic cycle of two stage condensation heat pump system is considered. Steady state conditions are analyzed for th...

In recent years, the study of branes has led to many new insights into string and M-theory. Much of this study was done in the large-volume regime where geometric techniques provide reliable information. The extrapolation into the stringy regime usually requires new methods from boundary conformal field theory. Branes on group manifolds give us a good handle on this issue. Although they describ...

[1] Fresh gully-like features on Mars strongly suggest that fluid flowed on the surface in the recent past. Here we consider the possibility that CO2 vapor-supported flows formed the gullies. We find that neither condensed CO2 nor CO2 clathrate hydrate are likely to accumulate in significant quantities in the Martian crust. In addition, if condensed CO2 were present under lithostatic pressures,...

This research addresses the flame structure of single aluminum particles burning in air with the emphasis on the transition from spherically symmetric to non-symmetric combustion regime. The unique feature of this work is that free motionless aluminum particles were produced and ignited in both normal and microgravity environments. That allowed us to observe whether the particle flame non-symme...