background: evaluating the factors influence student perception, might allow programmatic changes designed to enhance students’ psychosocial well-being and academic performance. the purpose of this study was to investigate perceived sources of stress on dental students and the role of parents in their career choice decisions. methods: in a cross-sectional design , a modified dental environmenta...

objectives: nowadays, snap-fits are used in the automotive industry as a proper alternative for mechanical joints, cabling joints, and car interior lining joints. due to the special form of these joints, which are assembled manually, the contact area between snap-fits and the worker's fingertips can be too small. this can cause skin pain on the worker's fingertips. therefore, an ergonomic study...

The success of the Green Revolution in closing the gap between world population and food production was principally achieved by increasing crop productivity in favorable areas. However, this success has been limited in the rainfed systems, which are prone to frequent droughts and other abiotic stresses. Worldwide, drought affects approximately 23 million hectares of rainfed rice. Varieties comb...

Models that invoke nonlinear wavefront propagation in a chemically excitable medium are rife in the biological literature. Indeed, the idea that wavefront propagation can serve as a signaling mechanism has often been invoked to explain synchronization of developmental processes. In this paper we suggest a kind of signaling based not on diffusion of a chemical species but on the propagation of m...

A unification of the gravitational with the electromagnetic interaction within a classical framework is proposed. It is based on a Fs-geometry, with x^ — qjm. The sole source term is mechanical stress energy, positioned along X5. The trajectories of testbodies are placed in V4 (xo = const)-slices. The final field equation couples a geometric G-tensor to mechanical stress energy, its momentum wi...

The elastic properties of DNA are essential for its biological function. They control its bending and twisting as well as the induction of structural modifications in the molecule. These can affect its interaction with the cell machinery. The response of a single DNA molecule to a mechanical stress can be precisely determined in single-molecule experiments which give access to an accurate measu...

The dimensions of microbumps in three-dimensional integration reach microscopic scales and thus necessitate a study of the multiscale microstructures in microbumps. Here, we present simulated mesoscale and atomic-scale microstructures of microbumps using phase field and phase field crystal models. Coupled microstructure, mechanical stress, and electromigration modeling was performed to highligh...

In this paper the effect of corrugated diaphragm on performance of MEMS microphone is described. The corrugated diaphragm is modeled in order to improve the sensitivity of micromachined silicon acoustic sensor. Analytical analyzes have been carried out to derive mathematic expressions for the mechanical sensitivity and displacement of corrugated diaphragm with residual stress. It is shown that ...

loading conditions and complex geometry have led the cylinder heads to become the most challenging parts of diesel engines. one of the most important durability problems in diesel engines is due to the cracks valves bridge area. the purpose of this study is a thermo-mechanical analysis of cylinder heads of diesel engines using a two-layer viscoplasticity model. in this article, mechanical prope...