A method to improve and automate flat defect detection during ultrasonic inspection

In the nondestructive testing of materials, ultrasonic imagery can detect and characterize defects that are present in a structure. Data are displayed in the form of images, and processing algorithms can be applied for automatic detection and characterization. However, when using diffracted waves, the amplitude is often too low, and the signals are difficult to distinguish from the noise. Other times, the volume of data requires significant computation time. In this paper, we propose a method that can avoid image formation by replacing it with a sparse matrix and significantly reducing the amount of data to process; this allows for the enhancement and the automation of the detection of thin and flat defects such as cracks. The elements of the sparse matrix form a curve, which is sufficient to characterize defects in many cases. These elements are selected from diffracted signals using the split‐spectrum processing method. In this way, the signal‐to‐noise ratio is improved, and the position of the echo signal is accurately determined. When a crack is present in a material, the points of the sparse matrix form a parabola and classical tools of pattern recognition such as the Hough transform can detect it, thus providing significant help in decision‐making processes. Copyright © 2011 John Wiley & Sons, Ltd.     

Applicability of Adapted Reservoir Operation for Water Stress Mitigation Under Dry Year Conditions

This paper introduces the conjunctive use of a deterministic water quality model and water balance criteria for supporting the assessment of simulation and to evaluate the effectiveness of proposed operation strategies. By this, the applicability of enhanced reservoir operation strategies addressing both water quality as well as water quantity aspects under water deficit conditions in dry years can be shown. Arguments will be developed to address stakeholders and decision makers in the context of a more conservative past operation regime. Results are presented for the Kaparas reservoir, which is located in the lower Amu Darya River, on the border of Turkmenistan and Uzbekistan. As being one out of four large reservoirs of the Tuyamuyun Hydro Complex (THC), the Kaparas reservoir could be increasingly used for drinking water supply for the lower Amu Darya region. The results for the dry year 2001 indicates that the combination of simulation together with practical assessment criteria confirm the applicability of adapted operation rules for THC reservoirs and ways can be found to supply the local population (of the lower Amu Darya region) with more potable water of higher quality even subject to a parallel reduction of water deficits. Future aggravation of water stress due to increasing population growth and water quality deterioration will require a more comprehensive consideration of water quality aspects in many arid and semi arid regions. The experience gained during this study emphasizes the fact that classical deterministic water quality models provide effective tools to address even more complex water quality problems under water stressed conditions, provided processing of results is performed, to support the decision making process.     

An Outage Analysis of Multibranch Diversity Receivers with Cochannel Interference in α-μ, κ-μ, and η-μ Fading Scenarios

Wireless communications systems in a frequency reuse environment are subject to cochannel interference. In order to improve the system performance, diversity techniques are deployed. Among the practical diversity schemes used, Equal-Gain Combining (EGC) appears as a reasonably simple and effective one. Unfortunately, the exact analysis of the outage probability of EGC receivers is rather intricate for it involves the evaluation of multifold nested integrals. It becomes mathematically intractable with the increase of the number of diversity branches and/or interferers. For example, for N _B diversity branches and N _I arbitrary independent cochannel interferers, the exact formulation using the convolutional approach requires 2 + N _B  + (N _B × N _I ) nested integrals, which, very quickly, and for any practical system, turns out to be mathematically intractable. In this paper, we propose accurate approximate formulations for this problem, whose results are practically indistinguishable from the exact solution. In our model, the system is composed by N _B branches and N _I interferers so that the desired signals are coherently summed, whereas the interfering signals are incoherently summed at the EGC receiver. Three sets of fading scenarios, namely α-μ , κ-μ, and η-μ, are investigated. The proposed approach is indeed flexible and accommodates a variety of mixed fading scenarios for desired and interfering signals.     

Diphenole und Caramelkomponenten in R?stkaffees verschiedener Sorten. II.

Zusammenfassung Elf Diphenole and sieben Caramelkomponenten wurden aus entfettetem Röstkaffee durch Extraktion mit Pentan/Äther (1 + 1) isoliert und nach Silylierung mit BSTFA gaschromatographischmassenspektrometrisch charakterisiert and größen-ordnungsmäßig bestimmt. Sieben Phenole und fünf Caramelkomponenten konnten erstmals in Röstkaffee identifiziert warden. Robustakaffee besitzt die größten Mengen an Phenolen and Maltol, während Arabica-kaffee die höchsten Konzentrationen an Furaneol (2,5-Dimethyl-4-hydroxy-3(2H)-furanen), Isomaltol, 5-Hydroxymaltol and 5-Hydroxy-5,6-dihydro-maltol aufweist.

---

Diphenols and caramel compounds in roasted coffees of different varieties. II.

Summary Eleven diphenols and seven caramel compounds were extracted from roasted coffee with pentane/ether (1 + 1), silylated with BSTFA, characterized, and semiquantified by GC-MS. Seven phenols and five caramel components were identified for the first time in roasted coffee.Robusta coffee contained the highest amounts of phenols and maltol.Arabica showed higher amounts of furaneol (2.5-dimethyl-4-hydroxy-3(2H)-furanone), isomaltol, 5-hydroxymaltol, and 5-hydroxy-5.6-dihydromaltol.

     

Regression of advanced atherosclerosis in swine

Advanced complicated atherosclerosis was produced in the abdominal aorta of swine by a combination of mechanical injury and high-cholesterol, high-fat diet for four months. After removal of the high-cholesterol diet and placing the animal on swine mash for 14 months, there was a significant (P less than .005) decrease in size of lesions with remodeling of the intima toward a smooth surface. Sudanophilia had virtually disappeared and atheromas were almost absent in the regression group, as were thrombosis and hemorrhage in plaques. Cell proliferation, as judged by the number of labeled cells in autoradiography, was less pronounced in this group. There was no decrease in the numbers of segments showing calcification; however, the size of the calcified areas was smaller in the regression group than in the base line. The data suggest that advanced atherosclerosis is susceptible to regression on removal of the atherosclerotic stimulus.     

The DVB-H Mobile Broadcast Standard

The digital video broadcasting-handheld (DVB-H) standard is one of the latest transmission standards developed by the digital video broadcasting (DVB) Project. DVB-H, which is based on the standard for digital terrestrial television (DVB-T), offers mobile television and other broadcasting services on small portable devices such as mobile phones. This article presents an overview of the DVB-H standard with respect to structure, features, technology, performance, and resources.     

Thermal conductivity of the vitreous system (ZnO) x −(P2O5)1−x

Glasses of the system (ZnO)_x–(P₂O₅)_1–x have been prepared by melting ZnO with anhydrous P₂O₅ in open crucibles. These glasses had compositions ranging from 20 to 70 mol % ZnO (chemically analysed ZnO mol %). Measurements of the thermal conductivity for the present glass system have been made in the temperature range 305 to 630 K. The thermal conductivity of this glass system is mainly due to lattice thermal vibrations. The thermal conductivity data are found to be fairly sensitive to the ZnO mol % content. It is observed from these data that the present glass system can be divided into three compositional regions. This behaviour is qualitatively explained in terms of changes in glass structure.     

Zinc-Blende MnTe Under Pressure: Structural,Mechanical, and Optical Properties from Ab Initio Calculation

We present first-principles studies of structural, mechanical, and optical properties of zinc blende MnTe using the pseudopotential plane-wave method within the local density approximation. The effect of hydrostatic pressure on investigated properties has been examined and discussed. At zero pressure, our results are found to agree reasonably well with those reported in the literature. The generalized elastic stability criteria showed that the material of interest is mechanically stable in all the studied pressure ranges. Applied pressure is found to shift all optical spectra under consideration, giving new optical parameters.