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The role of strain in material properties is well-established, serving as a tool for altering atomic positions and defect formation, adjusting electronic structures and lattice vibrations, and influencing phase transitions, physical characteristics, and chemical properties. In this study, we conducted theoretical calculations of the binding energy and photoionization cross section (PCS) within a spherical core/shell quantum dot (CSQD) for the different transitions between the ground state of a donor impurity and the four low-lying conduction band states. During our study, we employed the finite element method to determine the energy levels and wave functions of the system within the effective mass approximation. Subsequently, we investigated the changes in PCS and binding energy while varying shell width under the influence of an applied electric field, considering both cases with and without the effect of strain. The strain effect was incorporated based on Hooke's law, and we developed specific expressions and utilized the continuum linear elasticity mechanical model for a single spherically symmetric shell. The results demonstrate that the strain correction enhances the binding energy of the four low-lying energy levels, leading to a shift of the PCS peaks toward higher energies. Conversely, the application of an external electric field has varying effects depending on the specific transition being considered. We compared our theoretical results with available experimental data and found them to be in good agreement. The pronounced blue-shift and substantial enhancement in magnitude of PCS spectra concerning shell width, electric field, and strain make CSQDs highly promising candidates for applications in adjustable nano-optoelectronic devices. [ABSTRACT FROM AUTHOR]

Mixed convection is commonly used in electronic cooling processes and nuclear reactor technology. As a result, this study aims to demonstrate the mathematical formulation of fluid flow, heat and mass transfer under the controlling physical parameters such as mixed convection, buoyancy ratio, suction, magnetic field, and rotation angle of the sheet. The variation in the wall shrinking velocity, temperature and concentration is expressed as an exponential function. Since controlling equations are partial differential equations, similarity transformations convert these partial differential equations to ordinary differential equations. Finally, these ordinary differential equations are considered as a non-linear and non-dimensional boundary value problem. The final solution of these ordinary differential equations is obtained numerically by applying the Matlab bvp4c programme. Stability analysis which determines the most stable numerical solution between duel solutions is also made using the Matlab bvp4c programme. Comparing the obtained computational results to previously published data shows a good agreement. All numerical results are graphically illustrated and explained, including the velocity, temperature and concentration profiles, skin friction coefficient, local Nusselt number, and local Sherwood number. [ABSTRACT FROM AUTHOR]

Linear stability analysis is performed to study the effects of nonuniform basic temperature gradients on the onset of Rayleigh- Bénard-Marangoni electroconvection in a dielectric Eringen's micropolar fluid by using the Galerkin technique. In the case of Rayleigh-Bénard-Marangoni convection, the eigenvalues are obtained for an upper free/adiabatic and lower rigid/isothermal boundaries. The influence of various parameters has been analysed. Three nonuniform basic temperature profiles are considered and their comparative influence on onset of convection is discussed. Different values of feedback control and electric number are added up to examine whether their presence will enhance or delay the onset of electroconvection. [ABSTRACT FROM AUTHOR]

Metal matrix composites (MMCs) have become attractive in a variety of applications due to its advantage of having intermediate properties between metal and ceramic. This paper presents the investigation of the effect of sintering duration on mechanical properties of Al/SiC composites. In the present work, SiC particle reinforced Al matrix composites were produced via powder metallurgical processing. Pure aluminium powder with a particle size of 63 µm and silicon carbide powder with a particle size of 37µm were used. The range of sintering duration was 1, 2, 3, 4, 5 and 6 h at a fixed temperature of 590 °C. The compressive, hardness and impact tests were performed on the sintered samples to characterize the mechanical properties. It was found that as the sintering duration increased from 1 to 6 hours, the mechanical properties of the samples were enhanced. Furthermore, microscopic observations showed that the porosity level decreased as the sintering duration was increased. [ABSTRACT FROM AUTHOR]

This paper presents the investigation of the effect of sintering temperature on mechanical properties of Al/SiC composites. The composites were produced via conventional powder metallurgy processing. The particle size of Al and SiC powders are 63 µm and 37 µm respectively. The sintering temperatures exerted on the samples were 550, 570, 590, 610, 630 and 650°C at a fixed time of 1 h. The compressive, hardness and impact tests were performed on the sintered samples to characterize their mechanical properties. It was found that as the sintering temperature increase, the mechanical properties of the samples were also increased at earlier temperature and show a decrease trend thereafter. Similarly, this trend was also observed in the density test. Furthermore, microscopic observations showed that the porosity level decrease as the sintering temperature increase excluding at the temperature of 650°C. [ABSTRACT FROM AUTHOR]

Objective: This was a prospective and randomized study to compare the use of Human Patient Simulator (HPS) and conventional didactic teaching in enhancing medical undergraduates, understanding of crisis recognition and resuscitation. Methods: Following Research and Ethics Committee approval, 80 final year medical students were enrolled. The students were computer-randomized into two groups: - Group A for conventional teaching and Group B for Human Patient Simulator training. All the students were trained separately on four topics, i.e. tachycardia, asystole, ventricular fibrillation and heart block; 30 minutes for each topic. A 2-hour common lecture on all the topics was given prior to training. All trainings were conducted on one day. After a washout period of two days, the students were given a 75 minutes written test on crisis recognition and resuscitation. Results: The results were analyzed using SPSS version 14. Of the 80 students enrolled, 77 students followed the whole process of training. Group B with the Human Patient Simulator training (n = 37) achieved higher average mark compared to Group A with conventional training (n = 40), i.e. 70.22% vs 65.98%. This result was statistically significant (p < 0.05). However, there was no significant difference between the two groups' achievement when their results, which comprised of two components, crisis recognition and resuscitation, were analyzed separately. Conclusion: In conclusion, HPS was able to enhance the understanding of medical students in terms of crisis recognition and resuscitation. However, more researches are needed to further reveal its potential. [ABSTRACT FROM AUTHOR]

Objective: During the acute and post acute period following a mild traumatic brain injury (mTBI) multiple cognitive processes are negatively affected. Prior studies have reported numerous cognitive domains affected during the acute and post-acute period. Studies have demonstrated cognitive recovery, with subjective and objective assessments, that within days to weeks these cognitive abilities are recovered. This study examines the recovery of neurocognitive functions longitudinally. Method: In this study, we compared 12 adults entering an emergency department that met the criteria for a mTBI to a healthy control group of 13 adults. The neuropsychological evaluation for the mTBI group was performed within 10 days of the injury and 4 months following the injury. Results: The results demonstrate the mTBI group has significant deficits in processing speed, attention and concentration, as well as verbal and visual memory compared to the control group at baseline. The mTBI group showed cognitive recovery in most cognitive areas at the four month follow-up. Processing speed and visual memory were still significantly below the performance of the control group at the 4-month post-assessment. Conclusion(s): The results support prior studies that processing speed and memory may be the most sensitive cognitive domains affected by a mTBI. Furthermore, this study reveals individuals that experience a mTBI may still experience impairment in these cognitive domains 4-months post injury. [ABSTRACT FROM AUTHOR]

The features of electron-impurity polarizability in a quantum nanostructure are investigated from the knowledge of allowed electron states coupled to a shallow-donor impurity. The influence of geometry on the carrier confinement and the presence of external probes such as electric fields are explicitly considered. For the sake of illustration, the example of CdS/ZnSe-based prolate ellipsoidal core/shell quantum dot (PECSQD) configuration is chosen. This problem allows to consider a finite confinement potential model, employing both the finite element method and the effective mass approximation. Within this framework, impurity-related energies and associated polarizability for the lowest states were determined as functions of the shell thickness, core dimensions, impurity position, and applied electric field strength - while keeping the shell dimensions fixed. Electron-impurity energies are largely affected by electric field values. Under thinner shell conditions, polarizability shows variations with field strength that include "anomalous" negative values for certain states. Then, the increase in shell thickness causes a significant increment in the polarizabilities, regardless impurity position. • Electronic properties in prolate ellipsoidal core/shell quantum dots. • Effects of a shallow donor impurity. • Influence of externally applied electric field. • Calculation of electron-impurity polarizability for different allowed states. • Appearance of negative values of polarizability for certain excited states. [ABSTRACT FROM AUTHOR]