ISOKINETIC PEAK TORQUE OF CONCENTRIC AND ECCENTRIC CONTRACTION

The purpose of this study was to examine the isokinetic peak torque of plantar flexion and dorsiflexion in male and female. Seventy college students volunteered to participate in this study. Cybex-6000 dynamometer was employed in this study to examined the isokinetic concentric (CON) and eccentric (ECC) strength of ankle plantar flexion and dorsiflexion at 60, 120, 180, 240, and 300/s. Peak torques (PT) and peak torques relative to body mass for ankle plantar flexion and dorsiflexion were studied. The results indicated that ECC PT was greater than CON PT and plantar flexion PT was greater than dorsiflexion PT in both females and males. The ECC PT did not increase with increasing angular velocity. This study also showed that it was more reasonable to normalize PT relative to body mass when comparing the differences of strength between males and females

Thermal-mechanical modelling of power electronic module packaging

In this paper the reliability of the isolation substrate and chip mountdown solder interconnect of power modules under thermal-mechanical loading has been analysed using a numerical modelling approach. The damage indicators such as the peel stress and the accumulated plastic work density in solder interconnect are calculated for a range of geometrical design parameters, and the effects of these parameters on the reliability are studied by using a combination of the finite element analysis (FEA) method and optimisation techniques. The sensitivities of the reliability of the isolation substrate and solder interconnect to the changes of the design parameters are obtained and optimal designs are studied using response surface approximation and gradient optimization metho

Sensitivity Analysis of Arctic Sea Ice in CMIP5 Climate Model Simulations

The representative characteristics of the simulated 20th century North Hemisphere sea ice by the CMIP5 models have been evaluated against available observations and compared with those by the CMIP3 models. In addition to the analysis of conventional parameters, such as climatological mean and seasonal cycle of sea ice area (SIA), a transient sensitivity analysis of summer SIA to the changes in Arctic regionally averaged melting season surface air temperatures (SAT) was conducted to better understand physics behind model uncertainties (e.g., Gregory et al. 2004; Zhang 2010)

Applying GreenLab Model to Adult Chinese Pine Trees with Topology Simplification

International audienceThis paper applied the functional structural model GreenLab to adult Chinese pine trees (pinus tabulaeformis Carr.). Basic hypotheses of the model were validated such as constant allometry rules, relative sink relationships and topology simplification. To overcome the limitations raised by the complexity of tree structure for collecting experimental data, a simplified pattern of tree description was introduced and compared with the complete pattern for the computational time and the parameter accuracy. The results showed that this simplified pattern was well adapted to fit adult trees with GreenLab

Genome-wide meta-analyses identify three loci associated with primary biliary cirrhosis

A genome-wide association screen for primary biliary cirrhosis risk alleles was performed in an Italian cohort. The results from the Italian cohort replicated IL12A and IL12RB associations, and a combined meta-analysis using a Canadian dataset identified newly associated loci at SPIB (P = 7.9 x 10(-11), odds ratio (OR) = 1.46), IRF5-TNPO3 (P = 2.8 x 10(-10), OR = 1.63) and 17q12-21 (P = 1.7 x 10(-10), OR = 1.38)

Tensile behaviour of pitting corroded steel bars:Laboratory investigation and probabilistic-based analysis

Localised corrosion in steel bars has been a long-standing issue in the durability of reinforced concrete structures, but a comprehensive scheme for the analysis of pitting corroded steel bars, especially with respect to the deformation capacity, is not currently available. In this study, the morphological characteristics of 27 pitting steel bars were captured using a 3D scanner. The measured data were used to establish the probability distribution model of the cross-sectional areas of the corroded bars. Uniaxial tensile tests were conducted, and the evolving deformation field of the corroded bars was recorded through Digital Image Correlation (DIC). Based on the 3D reconstructed model and DIC results, an analytical method for evaluating the mechanical properties of pitting steel bars was developed and validated. The results show that the two-component Gaussian mixture distribution model outperforms conventional unimodal distribution models. Comparison of the analytical results with experimental data demonstrates that the proposed procedure is capable of predicting not only the ultimate strength but also the gauge length-dependent ultimate strain of corroded bars. Additionally, there exists a strengthening effect in the ultimate stress at the critical sections and this effect should not be ignored for accurate predictions.</p

Ferroelectric switching in ferroelastic materials with rough surfaces

Abstract: Electric switching of non-polar bulk crystals is shown to occur when domain walls are polar in ferroelastic materials and when rough surfaces with steps on an atomic scale promote domain switching. All domains emerging from surface nuclei possess polar domain walls. The progression of domains is then driven by the interaction of the electric field with the polarity of domain boundaries. In contrast, smooth surfaces with higher activation barriers prohibit effective domain nucleation. We demonstrate the existence of an electrically driven ferroelectric hysteresis loop in a non-ferroelectric, ferroelastic bulk material