Influence of carrier lifetime on quantum criticality and superconducting Tc of (TMTSF)_2ClO_4

This work presents and analyzes electrical resistivity data on the organic superconductor (TMTSF)$_2$ClO$_4$ and their anion substituted alloys (TMTSF)$_2$(ClO$_4$)$_{1-x}$(ReO$_4$)$_x$ along the least conducting $c^\star$ axis. Nonmagnetic disorder introduced by finite size domains of anion ordering on non Fermi liquid character of resistivity is investigated near the conditions of quantum criticality. The evolution of the $T$-linear resistivity term with anion disorder shows a limited decrease in contrast with the complete suppression of the critical temperature $T_c$ as expected for unconventional superconductivity beyond a threshold value of $x$. The resulting breakdown of scaling between both quantities is compared to the theoretical predictions of a linearized Boltzmann equation combined to the scaling theory of umklapp scattering in the presence of disorder induced pair-breaking for the carriers.Comment: 13 pages, 8 figure

Spatial Convergence in Height in East-Central Europe, 1890-1910

We examine spatial convergence in biological well-being in the Habsburg Monarchy circa 1890-1910 on the basis of evidence on the physical stature of 21-year-old recruits disaggregated into 15 districts. We find that the shorter was the population in 1890 the faster its height grew thereafter. Hence, there was convergence in physical stature between the peripheral areas of the monarchy (located in today's Poland/Ukraine, Romania, and Slovakia) and the core (located in today's Austria, Czech Republic, and Hungary). The difference between the trend in the height of the Polish district of Przemysl and the Viennese trend was about 0.9 cm per decade in favor of the former. But the convergence among the core districts themselves was minimal or non-existent, whereas the convergence among the peripheral districts was more pronounced. Hence, spatial convergence took place exclusively within the peripheral areas, and between the peripheral regions and the more developed ones. The pattern is somewhat reminiscent of modern findings on convergence clubs in the global economy. However, the East-Central European pattern was the reverse of this modern finding: heights converged to the levels of the developed regions, but did not converge among the more developed regions themselves

Creep-fatigue life assessment of cruciform weldments using the linear matching method

This paper presents a creep-fatigue life assessment of a cruciform weldment made of the steel AISI type 316N(L) and subjected to reversed bending and cyclic dwells at 550C using the Linear Matching Method (LMM) and considering different weld zones. The design limits are estimated by the shakedown analysis using the LMM and elastic-perfectly-plastic material model. The creep fatigue analysis is implemented using the following material models: 1) Ramberg-Osgood model for plastic strains under saturated cyclic conditions; 2) power-law model in “time hardening” form for creep strains during primary creep stage. The number of cycles to failure N? under creep-fatigue interaction is defined by: a) relation for cycles to fatigue failure N dependent on numerical total strain range "tot for the fatigue damage !f ; b) long-term strength relation for the time to creep rupture t dependent on numerical average stress ¯ during dwell t for the creep damage !cr; c) non-linear creep-fatigue interaction diagram for the total damage. Numerically estimated N? for different t and "tot shows good quantitative agreement with experiments. A parametric study of different dwell times t is used to formulate the functions for N? and residual life L? dependent on t and normalised bending moment ˜M , and the corresponding contour plot intended for design applications is created

Analysis of fatigue, fatique-crack propagation, and fracture data

Analytical methods have been developed for consolidation of fatigue, fatigue-crack propagation, and fracture data for use in design of metallic aerospace structural components. To evaluate these methods, a comprehensive file of data on 2024 and 7075 aluminums, Ti-6A1-4V, and 300M and D6Ac steels was established. Data were obtained from both published literature and unpublished reports furnished by aerospace companies. Fatigue and fatigue-crack-propagation analyses were restricted to information obtained from constant-amplitude load or strain cycling of specimens in air at room temperature. Fracture toughness data were from tests of center-cracked tension panels, part-through crack specimens, and compact-tension specimens

Principal Component Analysis of the Time- and Position-Dependent Point Spread Function of the Advanced Camera for Surveys

We describe the time- and position-dependent point spread function (PSF) variation of the Wide Field Channel (WFC) of the Advanced Camera for Surveys (ACS) with the principal component analysis (PCA) technique. The time-dependent change is caused by the temporal variation of the $HST$ focus whereas the position-dependent PSF variation in ACS/WFC at a given focus is mainly the result of changes in aberrations and charge diffusion across the detector, which appear as position-dependent changes in elongation of the astigmatic core and blurring of the PSF, respectively. Using >400 archival images of star cluster fields, we construct a ACS PSF library covering diverse environments of the $HST$ observations (e.g., focus values). We find that interpolation of a small number ($\sim20$) of principal components or ``eigen-PSFs'' per exposure can robustly reproduce the observed variation of the ellipticity and size of the PSF. Our primary interest in this investigation is the application of this PSF library to precision weak-lensing analyses, where accurate knowledge of the instrument's PSF is crucial. However, the high-fidelity of the model judged from the nice agreement with observed PSFs suggests that the model is potentially also useful in other applications such as crowded field stellar photometry, galaxy profile fitting, AGN studies, etc., which similarly demand a fair knowledge of the PSFs at objects' locations. Our PSF models, applicable to any WFC image rectified with the Lanczos3 kernel, are publicly available.Comment: Accepted to PASP. To appear in December issue. Figures are degraded to meet the size limit. High-resolution version can be downloaded at http://acs.pha.jhu.edu/~mkjee/acs_psf/acspsf.pd

Guidelines to select suitable parameters for contour method stress measurements

The contour method is one of the promising techniques for the measurement of residual stresses in engineering components. In this method, the cut surfaces deform, owing to the relaxation of residual stresses. The deformations of the two cut surfaces are then measured and used to back calculate the 2-dimensional map of original residual stresses normal to the plane of the cut. Thus, it involves four main steps; specimen cutting, surface contour measurement, data analysis and finite element simulation. These steps should perform in a manner that they do not change the underlying features of surface deformation especially where the residual stress distribution varies over short distances. Therefore, to carefully implement these steps, it is important to select appropriate parameters such as surface deformation measurement spacing, data smoothing parameters (‘knot spacing’ for example cubic spline smoothing) and finite element mesh size. This research covers an investigation of these important parameters. A simple approach for choosing initial parameters is developed based on an idealised cosine displacement function (giving a self-equilibrated one-dimensional residual stress profile). In this research, guidelines are proposed to help the measurer to select the most suitable choice of these parameters based on the estimated wavelength of the residual stress field