Characterizing In‐Plane Geometrical Variability in Textile Ceramic Composites

We present a methodology for characterizing and reconstructing in‐plane weave variability in textile composites. Surface topography of a partially processed C‐fiber/SiC matrix composite panel was measured using digital image correlation. The centroids of tow segments that appear periodically on the fabric surface were located by image analysis and used as fiducial markers. Stochastic deviations of the fiducial markers from the ideal periodic weave structure indicate geometrical variance. Fourier analysis shows that spatial wavelengths of the deviations range from the size of one unit cell to the dimensions of the entire panel. Long‐range deviations are attributed principally to fabric deformation after manufacture, during handling. Short‐range fluctuations, extracted by computing spatial derivatives of the positions of the fiducial markers, are attributed to variations in tow packing density that arises during weaving. A simple set of statistics for these deviations is presented and its use in generating stochastic virtual specimens is demonstrated.     

单片同步降压型转换器LTC3416

许多微处理器和数字信号处理器(DSP)需要一个核心电源和一个在启动期间必须进行排序的输入／输出(I／O)电源。如果未经过适当的电源排序，可能发生闭锁或过流，从而损害微处理器的I／O端口或诸如存储器、逻辑电路、现场可编程门阵列(FPGA)或数据转换器之类支持设备的I／O端口。为了确保在主电源电压未被适当偏置之前I／O负载不被驱动，对核心电源电压和I／O电源电压进行跟踪是必要的。     

Scale-space for discrete signals

A basic and extensive treatment of discrete aspects of the scale-space theory is presented. A genuinely discrete scale-space theory is developed and its connection to the continuous scale-space theory is explained. Special attention is given to discretization effects, which occur when results from the continuous scale-space theory are to be implemented computationally. The 1D problem is solved completely in an axiomatic manner. For the 2D problem, the author discusses how the 2D discrete scale space should be constructed. The main results are as follows: the proper way to apply the scale-space theory to discrete signals and discrete images is by discretization of the diffusion equation, not the convolution integral; the discrete scale space obtained in this way can be described by convolution with the kernel, which is the discrete analog of the Gaussian kernel, a scale-space implementation based on the sampled Gaussian kernel might lead to undesirable effects and computational problems, especially at fine levels of scale; the 1D discrete smoothing transformations can be characterized exactly and a complete catalogue is given; all finite support 1D discrete smoothing transformations arise from repeated averaging over two adjacent elements (the limit case of such an averaging process is described); and the symmetric 1D discrete smoothing kernels are nonnegative and unimodal, in both the spatial and the frequency domain     

未来派手机

<正>未来的手机就是:越来越不像手机。在高科技发展的21世纪,很多事物都打着概念的旗号。比如手机,为了迎合消费者个性的需要,其功能会越来越强大、材质会越来越环保、形状会越来越奇异。也许会出现随天气变化而变化屏幕效果的手机,也许会出现腕表、戒指一样的手机,也许会出现木头手机,还也许会出现可以     

Metabolomic Profiling of Plasma from Melioidosis Patients Using UHPLC-QTOF MS Reveals Novel Biomarkers for Diagnosis

To identify potential biomarkers for improving diagnosis of melioidosis, we compared plasma metabolome profiles of melioidosis patients compared to patients with other bacteremia and controls without active infection, using ultra-high-performance liquid chromatography-electrospray ionization-quadruple time-of-flight mass spectrometry. Principal component analysis (PCA) showed that the metabolomic profiles of melioidosis patients are distinguishable from bacteremia patients and controls. Using multivariate and univariate analysis, 12 significant metabolites from four lipid classes, acylcarnitine (n = 6), lysophosphatidylethanolamine (LysoPE) (n = 3), sphingomyelins (SM) (n = 2) and phosphatidylcholine (PC) (n = 1), with significantly higher levels in melioidosis patients than bacteremia patients and controls, were identified. Ten of the 12 metabolites showed area-under-receiver operating characteristic curve (AUC) >0.80 when compared both between melioidosis and bacteremia patients, and between melioidosis patients and controls. SM(d18:2/16:0) possessed the largest AUC when compared, both between melioidosis and bacteremia patients (AUC 0.998, sensitivity 100% and specificity 91.7%), and between melioidosis patients and controls (AUC 1.000, sensitivity 96.7% and specificity 100%). Our results indicate that metabolome profiling might serve as a promising approach for diagnosis of melioidosis using patient plasma, with SM(d18:2/16:0) representing a potential biomarker. Since the 12 metabolites were related to various pathways for energy and lipid metabolism, further studies may reveal their possible role in the pathogenesis and host response in melioidosis.     

A load-balanced parallel sorting algorithm for shared-nothing architectures

With the popularity of parallel database machines based on the shared-nothing architecture, it has become important to find external sorting algorithms which lead to a load-balanced computation, i.e., balanced execution, communication and output. If during the course of the sorting algorithm each processor is equally loaded, parallelism is fully exploited. Similarly, balanced communication will not congest the network traffic. Since sorting can be used to support a number of other relational operations (joins, duplicate elimination, building indexes etc.) data skew produced by sorting can further lead to execution skew at later stages of these operations. In this paper we present a load-balanced parallel sorting algorithm for shared-nothing architectures. It is a multiple-input multiple-output algorithm with four stages, based on a generalization of Batcher's odd-even merge. At each stage then keys are evenly distributed among thep processors (i.e., there is no final sequential merge phase) and the distribution of keys between stages ensures against network congestion. There is no assumption made on the key distribution and the algorithm performs equally well in the presence of duplicate keys. Hence our approach always guarantees its performance, as long asn is greater thanp ³, which is the case of interest for sorting large relations. In addition, processors can be added incrementally. Recommended by: Patrick Valduriez     

MICROSCALE ENGINEERING APPLICATIONS IN BONE ADAPTATION

Advances in cell biology have been dramatic over the past two decades. One phenomenon now well established is that the mechanical loading of cells has a profound influence on their function. This phenomenon is particularly important for bones, because they alter their density and geometry in response to mechanical loading. In an attempt to understand and ultimately control the underlying biological mechanisms of this bone adaptation, researchers are now mechanically probing whole bones, bone cell cultures, and individual cells using a variety of microscale technologies. There is, however, a substantial need for improved technology. The overall goal of this review is to encourage the participation of the microscale engineering community in this new field of research. Specifically, we describe here possible clinical applications, introduce some basic concepts of bone and cell biology, describe the current microscale technology used in this field, and critically review experiment results. This should provide a basis for the entry of interested microscale engineers into this field.     

Marketing and selling solar energy equipment

The literature on creating consumer awareness and acceptance of solar water heating systems for marketing purposes is sparse. This paper discusses some of the sophisticated marketing techniques available and some results.Selling solar water heating systems in Northern European latitudes requires a degree of persistence and commitment that is probably not required in what are regarded as the “sunny climes” around the Mediterranean, the Middle East, Africa, South East Asia and Australasia.     

TWO-DIMENSIONAL SCHEME FOR CONVECTION-DIFFUSION WITH LINEAR PRODUCTION

In this article we consider the scalar transport governed by the convection-diffusion equation with linear production in two dimensions. The underlying idea in the development of a steady discretization scheme is to incorporate the analytical solution, obtained within a one-dimensional context, into the formulation. The method adopted here features exponential character in the weighted coefficients of the matrix equation, which generates a scheme with high accuracy. The analysis is followed by extending this discretization scheme to solve the convection-diffusion-production equation with a source term. In this article we present an analytical validation study of the method applied to two classes of model equations. Having verified that the method applies equally well for a transport scalar in either case with constant or variable flow velocity, we employ the one-dimensional scheme in the predictor and corrector steps to obtain the two-dimensional solution in an alternating direction-implicit fashion. The result obtained for the test considered in this article follows the trend of analytic data.