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...

A network of entangled multiwall carbon nanotubes is an assembly of non-bonded and randomly oriented units whose mechanical behavior is affected by their buckling, compression and slippage at contact points. Slippage and irreversible nanotube rearrangements are evidenced by the hysteresis in the stress-strain curves during loading and unloading cycles. To model the mechanical behavior, a nonlin...

Symmetries of a partial Latin square are primarily determined by its autotopism group. Analogously to the case of Latin squares, given an isotopism Θ, the cardinality of the set PLSΘ of partial Latin squares which are invariant under Θ only depends on the conjugacy class of the latter, or, equivalently, on its cycle structure. In the current paper, the cycle structures of the set of autotopisms...

The purpose of this study was to evaluate the amount and quality of scientific evidence supporting principles that are currently applied for cardiopulmonary bypass (CPB) performance. The scientific data concerning the effectiveness and safety of key principles of cardiopulmonary bypass is insufficient in both amount and quality to serve as a basis for practical, evidence-based guidelines.

A center manifold reduction and numerical calculations are used to demonstrate the presence of limit cycles, two-tori, and multistability in the damped harmonic oscillator with delayed negative feedback. This model is the prototype of a mechanical system operating with delayed feedback. Complex dynamics are thus seen to arise in very plausible and commonly occurring mechanical and neuromechanic...

BACKGROUND In patients with transient azoospermia, few sperm may be found in the ejaculate. We investigated the outcome of ICSI in patients with transient azoospermia. METHODS Records of patients with transient azoospermia referred during a 42 month period were reviewed. If only immotile sperm were found, the sample was incubated with 30% human serum albumin (HSA) before motility re-assessmen...

Thermoelectric modules experience performance reduction and mechanical failure due to thermomechanical stresses induced by thermal cycling. The present study subjects a thermoelectric module to thermal cycling and evaluates the evolution of its thermoelectric performance through measurements of the thermoelectric figure of merit, ZT, and its individual components. The Seebeck coefficient and th...

The UCLA Academic Senate has completed its review of the UCPB Paper on Differential Fees and Nonresident Tuition. The proposal has been reviewed by our Council on Planning and Budget (CPB), Graduate Council, Undergraduate Council, Committee on Undergraduate Admissions and Relations with Schools, and numerous Faculty Executive Committees (School of Arts and Architecture, School of Theater, Film,...

The Charité(®) lumbar intervertebral disc replacement was subjected to wear testing in an electro-mechanical spine simulator. Sinusoidally varying compression (0.6-2 kN, frequency 2 Hz), rotation (±2°, frequency 1 Hz), flexion-extension (6° to -3°, frequency 1 Hz) and lateral bending (±2°, frequency 1 Hz) were applied out of phase to specimens immersed in diluted calf serum at 37 °C. The mass o...

Fracture repair is influenced by the mechanical environment, particularly when cyclic loads are applied across the fracture site. However, the specific mechanical loading parameters that accelerate fracture healing are unknown. Intact bone adaptation studies show enhanced bone formation with pauses inserted between loading cycles. We hypothesized pause-inserted noninvasive external loading to m...