Recently, non-mechanical micropumps have become more appealing, due to their advantages in many areas such as electronics and medicine. In this research, a PHASE CHANGE micropump, as a novel type of nonmechanical micropump, has been investigated. Dimensionless parameters have been determined using dimensional analysis and a one dimensional steady model has been developed to describe the pumping mechanism and assess the working characteristics of the micropump. The results show that the theoretical model is in reasonable agreement with the experimental investigations. This analytical approach can be used in the design and fabrication of more efficient micropumps.

In this study, we investigated the PHASE behavior of rods with square ( ) and circular (diameter D) cross sections between two hard walls using the Parsons-Lee theory and applying the Zwanzig approximation. Our focus is to find wall-to-wall separations (H) and the size of particles in which the PHASE of the system CHANGEs without occurring a PHASE transition. It was determined that if the distance between the plates is smaller than the length of the particles, for any particle whose length (L) to diameter ratio is greater than 1, the second order PHASE transition occurs, and most of the particles are placed in a certain direction parallel to the plates, which this type of PHASE transition takes place at lower densities with increasing particle’s aspect ratio. We also came to the conclusion that if the distance between the plates is greater than and , despite the PHASE CHANGE of the system with increasing particle density, no PHASE transition will occur. In addition, it was found that the cylindrical shaped particles show some unexpected behaviors, which could be due to the inappropriate performance of the applied theory or their real physical behavior, which requires more detailed studies to resolve the ambiguity.

The problems of heat and mass transfer in PHASE CHANGE materials are of great engineering interest. The absorption and storage of energy in the form of latent heat makes it possible to use them in the construction industry to smooth out the effects of temperature transitions in the environment. This work is devoted to the study of heat transfer in a building block with paraffin inserts under unsteady external conditions. The influence of the geometric dimensions of the block and the volume fraction of the PHASE CHANGE material on the effect of restraining external temperature fluctuations was studied. The unsteady conjugate melting problem was solved in a closed rectangular region with two cavities filled with PCM. The temperature of the environment on the left boundary CHANGEs in harmonic law. Thermal distributions were obtained at various points in time.

The one PHASE Stefan problem is discussed using the Goodman HBI method and an explicit numerical method including modified boundary immobilization scheme. The main advantage of the HBI method lie in the remarkable association of simplicity, flexibility and acceptable accuracy which an error less than 2.5% in predicting the moving front location for Stefan number less than unity which covers most usual isothermal PHASE CHANGE material. An accurate explicit numerical model to track the moving front in Stefan-like problems is provided. The scheme is obtained using the variable space step method based on variable domain. The method is developed using central difference approximations to replace spatial and temporal derivatives. Furthermore, iterative procedure, in numerical calculation, is avoided by introducing simple assumptions. The numerical results show that the accuracy of the method has been considerably improved without additional computational cost.

Introduction: In spite of its short time period compared with the earth long evolution history, quaternary has had a significant effect on the final formation of the landforms and vital resources. It is the final analysis of these levels and fully dependent on the earth genetic diseases and, above all, significant climate CHANGEs that have happened during this period. Gavkhouni basin morphological perspectives demonstrate several climate CHANGEs in quaternary. The effects of these CHANGEs are a completely known phenomenon on the lake. Indeed, the lake can be viewed as an archive within which quaternary climate CHANGEs evidence has been maintained....

Having a reliable, low-cost, and always available energy production system has announced the energy storage systems as an important candidate. There are different methods to store renewable energies, which the storage of latent heat energy is more important one because of its ability to generate high energy storage density at constant temperature (PHASE CHANGE PHASE). Organic or inorganic compounds that are capable of absorbing and storing large amounts of heat energy are called PHASE-CHANGE materials. Due to the high efficiency and high capicity of PHASE-CHANGE materials in energy storage systems, the use of these materials in recent years has attracted many developed countries. The purpose of this paper is to review the various types of PHASE-CHANGE materials, the application systems and the other researches on these materia ls.