A three-valley Monte Carlo simulation approach was used to investigate electron transport in wurtzite GaN such as the drift velocity, the drift mobility, the average electron energy, energy relaxation time, and momentum relaxation time at high electric fields. The simulation accounted for polar optical phonon, acoustic phonon, piezoelectric, intervalley scattering, and Ridley charged impurity scattering model. For the steady-state transport, the drift velocity against electric field showed a negative differential resistance of a peak value of 2.9×105 m/s at a critical electric field strength 180×105 V/m. The electron drift velocity relaxes to the saturation value of 1.5×105 m/s at very high electric fields. The electron velocities against time over wide range of electric fields are reported.

Transient creep tests are performed under constant stress conditions at temperatures ranging from 373 to 453 K for Sn‐0.5 wt% Zn, Sn‐9 wt% Zn, and Pb‐10 wt% Sn, and from 363 to 433 K for Pb‐61.9 wt% Sn samples. The transient creep is described by ϵtr = Btn, where ϵtr and t are the transient creep strain and time. The parameters B and n are calculated. The activation enthalpy of the transient creep shows for each alloy two regions at low and high temperatures. The values of activation enthalpies show that the mechanism controlling transient creep in Sn‐Zn alloys is a dislocation mechanism, while in Pb‐Sn alloys it consists of dislocation intersections and grain boundary diffusion.

Background: Children who have hearing impaired need exceptional attention from their families, especially from mothers, as they are the most person contact with their children from birth and throughout life. Aim: The study aimed to assess the mothers' awareness towards care of their children suffering from hearing loss. Design: A descriptive design utilized in carrying out this study. Setting:The study conducted at the at hearing test unit at Hearing and Speech Institute outpatient clinics in Imbaba which affiliated to General Organization for Teaching Hospitals and Institutes, MOH, in Cairo. Sample: A convenient sample composed of 150 mothers having children suffering from hearing loss who attend to the previously mentioned setting. Tools: It consisted of three tools.(1) A pre-designed questionnaire sheet which consist of two parts: part(1) to assess characteristics of study subjects, part (2) to assess mothers' knowledge about hearing loss, (2) Mothers' reported practices regarding care of their children suffering from hearing loss and (3) Mothers attitude regarding care of their children suffering from hearing loss. Results: More than two thirds of the studied mothers have unsatisfactory knowledge about hearing loss and less than two thirds of them had inadequate reported practices regarding care of their children. In addition, less than three quarters of the studied mothers had positive attitude toward care of their children suffering from hearing loss. Conclusion: Based on the study findings, can be concluded that, there are strong positive correlations between mothers' total knowledge, total reported practices and total attitude regarding care of their children suffering from hearing loss. Recommendation: Conducting an educational programs for mothers to upgrade their knowledge, reported practices and communication with children suffering from hearing loss.

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