when the orbital altitude of a small satellite is near-earth, passive stabilization can be considered. the purpose of this paper is to combine the passive gravity gradient and aerodynamic stabilization methods together so that all the three axes stabilizations can be obtained. in this regard, the set of nonlinear equations of motion will be solved numerically with specified initial condition. t...

Although industrial and commercial uses of mercury have been curtailed in recent times, there is a demonstrated need for the development of reliable hazardous waste management techniques because of historic operations that have led to significant contamination and ongoing hazardous waste generation. This study was performed to evaluate whether the U.S. EPA could propose treatment and disposal a...

Striking differences in the solidification textures of a nickel based alloy owing to changes in laser scanning pattern during additive manufacturing are examined based on theory and experimental data. Understanding and controlling texture are important because it affects mechanical and chemical properties. Solidification texture depends on the local heat flow directions and competitive grain gr...

Storing of available energy for later use is a necessity in the present world, one such method is using Phase Change Materials (PCMs). PCMs need a heat transfer medium to transfer the energy from the source to the PCM. In this present work spherical balls are used to store the PCM and water is used as a heat transfer fluid. Paraffin wax (PW) and Palmitic acid (PA) and (4060% PW-PA) eutectic mix...

Presented work shows the results of DSC measurement for six Sn based solders. The alloys Sn96Ag4, Sn99Cu1, Sn97Cu3, Sn96.5Ag3Cu0.5, Sn95.5Ag3.8Cu0.7 and Sn63Pb37 were studied in the temperature range from room temperature up to 400◦C. The transformation temperatures for melting as well as for solidification were influenced by the composition and thermal history of the alloys. The thermal histor...

In typical solidification processes the flow of molten metal is usually regarded as an unavoidable phenomenon potentially affecting the morphology of dendritic growth. Fundamental understanding of such flow is thus important for predicting and controlling solidification microstructures. This paper presents numerical simulations on the evolution of dendritic microstructures with melt convection....

Kinetic phase diagrams in technical alloys at different solidification velocities during rapid solidification are of great importance for guiding the novel alloy preparation, but are usually absent due to extreme difficulty in performing experimental measurements. In this paper, a phase-field model with finite interface dissipation was employed to construct kinetic phase diagrams in the ternary...

Electron beam welds between dissimilar stainless steels with different solidification modes were studied with a view to elucidating the role of nucleation, cooling rate and direction of dendrite growth on the tendency towards metastable phase solidification. The results are compared with the solidification behaviour of levitation melted samples. It is demonstrated that with careful design, stai...

today, environmental crisis and loss of natural resources are the principle causes of the creation of environmental management systems. the optimal management of natural resources requires the assessment and classification of ecological and environmental potentials. using this method, the abilities and restrictions of resources can be recognized, and their future trends can be predicted. nebka ...

A comprehensive methodology that takes into account alloy solidification, shrinkage-driven interdendritic fluid flow, hydrogen precipitation, and porosity evolution has been developed for the prediction of microporosity fraction in aluminum A356 alloy castings. The mathematical models presented are implemented in a computational framework consistent with those of commercial casting codes, allow...