Activating cement mixing water with the relaxation processes

The analysis of relaxation processes in water activated by thermal or ultraviolet radiation has been carried out. The activation of the mixing water leads to an earlier hardening of the cement. At the same time, activated water loses its properties with a relaxation time, which is equal to the activity time of melt water, which is explained by the common reasons for the origin of the increased reaction properties of activated water and melt water. These properties are due to the fact that activation increases the content of free water molecules. In the normal state, some of the water molecules enter the voids of fractal-clathrate structures. During thermal or radiation activation processes, characterized by certain relaxation times, these structures are destroyed, and free water molecules are released. But after the termination of activation, relaxation processes take place to restore thermodynamically equilibrium fractal-clathrate structures, and part of the free water is again captured by these structures. Therefore, the reactivity of water after the termination of activation decreases.

Bioconvection in Cross Nano-Materials with Magnetic Dipole Impacted by Activation Energy, Thermal Radiation, and Second Order Slip

Ferro liquids derive their magneto–viscous behavior from the suspended magnetic nanomaterial that enables tunable changes in temperature, as well as nano-structured fluid characteristics. A theoretical model that depicts the bioconvection flow of cross nanofluid with a magnetic dipole subjected to a cylindrical surface was developed and numerically solved. The model encountered nonlinear thermal radiation, activation energy, and second order slip. The flow equations were reduced and are presented in dimensionless forms, and they were solved numerically using the shooting technique, which is a built-in feature of MatLab. The model encountered symmetrical constraints for predicting velocity, temperature, concentration, and gyrotactic microorganism distribution and profiles. Moreover, the numerical values were computed for local Nusselt number, local Sherwood number, and motile density number against each physical parameter.

Aging of InGaN/AlGaN/GaN Light-Emitting Diodes

Changes in luminescent spectra, current-voltage, and capacitance-voltage characteristics were studied versus time of working at forward currents for light-emitting diodes based on InGaN/AlGaN/GaN heterostructures. The samples of blue and green LEDs with a single quantum well InGaN active layers were studied during 102-2.103 hours at currents 30–80 mA. An increase in efficiency at the first stage and a decrease one at the second stage were detected. The main changes were detected at low currents in blue diodes for tunnel components of current and radiation. Activation of acceptors Mg because of residual H atoms are going out of complexes Mg-H and creation of donor type defects are proposed as models for two stages. A model of injection stimulated (non-thermal) underthreshold creation of defects can explain the results.