Fractal analysis of weld defect patterns obtained by radiographic tests

This paper presents a fractal analysis of radiographic patterns obtained from specimens with three types of inserted welding defects: lack of fusion, lack of penetration, and porosity. The study focused on patterns of carbon steel beads from radiographs of the International Institute of Welding (IIW). The radiographs were scanned using a greyscale with 256 levels, and the fractal features of the surfaces constructed from the radiographic images were characterized by means of Hurst, detrended-fluctuation, and minimal-cover analyses. A Karhunen-Loeve transformation was then used to classify the curves obtained from the fractal analyses of the various images, and a study of the classification errors was performed. The obtained results indicate that fractal analyses can be an effective additional tool for pattern recognition of weld defects in radiographic tests.Comment: 7 pages, 2 figures. To appear AIP Conference Proceedings - QNDE 200

Politics of Fashion in Dubai

Modesty is fashionable. Long black gowns called abayas over many women from head to toe, and the hijab or scarf covers the head and is draped over the shoulders. Since it is generally difficult to say whether religion or culture dictates this sartorial choice, it remains a debated issue, both within and outside academia. Contests about the position and place of women are a continuing feature of Muslim (and perhaps all) societies. Critiques about the 'Western style' of modernization have increasingly become centred around the question of women's chastity, modesty and sexuality. As is almost always the case, it is on the figure of the woman that the responsibility of maintaining tradition and upholding family values becomes centred

Solving the time-dependent Schr\"odinger equation with absorbing boundary conditions and source terms in Mathematica 6.0

In recent decades a lot of research has been done on the numerical solution of the time-dependent Schr\"odinger equation. On the one hand, some of the proposed numerical methods do not need any kind of matrix inversion, but source terms cannot be easily implemented into this schemes; on the other, some methods involving matrix inversion can implement source terms in a natural way, but are not easy to implement into some computational software programs widely used by non-experts in programming (e.g. Mathematica). We present a simple method to solve the time-dependent Schr\"odinger equation by using a standard Crank-Nicholson method together with a Cayley's form for the finite-difference representation of evolution operator. Here, such standard numerical scheme has been simplified by inverting analytically the matrix of the evolution operator in position representation. The analytical inversion of the N x N matrix let us easily and fully implement the numerical method, with or without source terms, into Mathematica or even into any numerical computing language or computational software used for scientific computing.Comment: 15 pages, 7 figure

Storage and transport in cave seepage- and groundwater in a South German karst system

International audienceWe investigated one of the best-known and second largest karst areas in Germany (Blautopf Catchment) that offers a unique access waters of the unsaturated zone through a large cave system. As tracers for water flow and storage we measured stable isotopes (18O/16O and D/H ratios) in precipitation, seepage- and groundwater. The precipitation showed a distinct seasonal cycle with ?18O values between ?2.6 and ?22.6? during summer and winter, respectively. However, the isotope signals in seepage water in the caves as well as the discharge were completely buffered and ranged around an average ?18O value of ?10?. This value also matched the long-term average of the precipitation. In addition, the homogeneous isotopic composition of the Blautopf Spring was against expectation for its highly variable discharge (0.3 to 32 m3 s?1) that is typical for a fast responsive karst system. We explain the isotopic similarity between cave seepage and the Blautopf Spring (as an integral signal for groundwater) by nearly complete mixing of the water already in the vadose zone. The latter can be divided into the compartments soil, epikarst and rock matrix that all have good storage capacities and also allow diffusive exchange of solutes between mobile and less mobile matrix water. The above approach revealed new aspects about turnover and flow paths of the infiltrated water and thus helps to constrain the risk by pollution to the groundwater

Tuning hole mobility in InP nanowires

Transport properties of holes in InP nanowires were calculated considering electron-phonon interaction via deformation potentials, the effect of temperature and strain fields. Using molecular dynamics, we simulate nanowire structures, LO-phonon energy renormalization and lifetime. The valence band ground state changes between light- and heavy-hole character, as the strain fields and the nanowire size are changed. Drastic changes in the mobility arise with the onset of resonance between the LO-phonons and the separation between valence subbands.Comment: 4 pages, 4 figure

Searches for axion-like particles via γγ\gamma \gamma fusion at future e+e−\mathrm{e}^+\mathrm{e}^- colliders

Opportunities for searches for axion-like particles (ALPs) coupling to photons in $\mathrm{e}^+\mathrm{e}^-$ collisions at the Future Circular Collider (FCC-ee) and International Linear Collider (ILC) are investigated. We perform a study of the photon-fusion production of ALPs decaying into two photons, $\mathrm{e}^+\mathrm{e}^- \overset{\gamma \gamma}{\longrightarrow} \mathrm{e}^{+}\;a(\gamma \gamma)\;\mathrm{e}^{-}$, over the light-by-light continuum background, for the planned FCC-ee and ILC center-of-mass energies and integrated luminosities. An analysis of the feasibility measurements is presented using parametrized simulations for two types of detectors. Upper limits at 95% confidence level (CL) on the cross section for ALP production, $\sigma(\gamma \gamma \to a \to \gamma \gamma)$, and on the ALP-photon coupling are obtained over the $m_a \approx 0.1$--1000 GeV ALP mass range, and compared to current and future collider searches. Production cross sections down to $\sigma(\gamma \gamma \to a \to \gamma \gamma) \approx 1$ fb (1 ab) will be probed at $m_a\approx 1$ (300) GeV, corresponding to constraints on the axion-photon coupling as low as $g_\mathrm{a\gamma \gamma} \approx 2\cdot10^{-3}$ TeV$^{-1}$

Morphometric structure of the jumbo tiger prawn, Penaeus monodon Fabricius, 1798 from southeast and southwest coasts of India

Morphometric variables were measured to detect variation among the random population samples of Penaeus monodon from east and west coast - Kochi, Calicut, Mangalore, Karwar, Kakinada and Chennai of India. Among these variables, PCL showed the highest correlation with the tail weight (TLW) in both males (0.9605) and females (0.9639). Truss network analysis of 26 measurements from the six centres were log transformed and were subjected to Principal Component Analysis and accounted a total of 89.15% variations in truss measurements data and showed no separate cluster formation in the plot of sheared PC scores and hence confirm homogeneous stock structure