Home About us Contact
|
Home About us Contact | ||
|
|
||
Test Measurements (test + measurement)
Selected AbstractsOrdered Mesoporous In2O3: Synthesis by Structure Replication and Application as a Methane Gas SensorADVANCED FUNCTIONAL MATERIALS, Issue 4 2009Thomas Waitz Abstract The synthesis and characterization of ordered mesoporous In2O3 materials by structure replication from hexagonal mesoporous SBA-15 silica and cubic KIT-6 silica is presented. Variation of the synthesis parameters allows for different pore sizes and pore wall thicknesses in the products. The In2O3 samples turn out to be stable up to temperatures between 450,°C and 650,°C; such high thermal stability is necessary for their application as gas sensors. Test measurements show a high sensitivity to methane gas in concentrations relevant for explosion prevention. The sensitivity is shown to be correlated not only with the surface-to-volume ratio, but also with the nanoscopic structural properties of the materials. [source] Improved analogue fault coverage estimation using probabilistic analysisINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5 2010D. K. Papakostas Abstract A method for fault detection probability estimation using statistical multi-parameter circuit simulation is proposed, in order to check circuits for which double or multiple analogue measurements are utilized. Theoretical analysis for the estimation of the fault coverage is given, based on conditional probability calculations. The proposed method can be applied for both test measurement and input stimulus selection. Simulation results from the application of the method on typical analogue circuits,filter and amplifier,are given, showing a sufficient improvement over the fault coverage achieved by single measurements. Copyright © 2009 John Wiley & Sons, Ltd. [source] Direct near-field antenna testing and fault diagnosis by a silicon-probe-based optical sensing techniqueMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2003R. Massa Abstract A non-perturbing, fast, low-cost probe for near-field measurements is presented in this paper. The new sensing technique's capabilities in antenna fault diagnosis and direct measurement of field intensity distribution at subwavelength distance from the sources are demonstrated by test measurement on different microwave antennas and applicators. © 2003 Wiley Periodicals, Inc. Microwave Opt Technol Lett 38: 95,98, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10981 [source] Using the TPS method for determining the thermal properties of concrete and wood at elevated temperatureFIRE AND MATERIALS, Issue 5 2006Bijan Adl-Zarrabi Abstract The transient plane source (TPS) method is shown to be very promising for determining thermal properties of materials at room temperature as well as temperatures up to 700°C. To investigate the applicability of the method it has been used in the study for determining thermal properties of wood (spruce) and concrete. Conductivity (,) and diffusivity (,) were determined simultaneously. The thermal properties thus obtained have been compared with some values found in literature. The paper also presents results where calculations using properties obtained with the TPS method are compared with fire test measurements. The results are very encouraging. Copyright © 2005 John Wiley & Sons, Ltd. [source] Ground water level influence on thermal response test in Adana, TurkeyINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 7 2008. Bozda Abstract For optimum design of borehole thermal energy storage (BTES) and ground sources heat pump (GSHP) applications, determination of underground thermal properties is required. The design and economic feasibility (number and depth of boreholes) of these systems need thermal conductivity of geological structure, , (W,m,1,K,1), and thermal resistance of ground heat exchanger, R (K,W,1,m). Thermal properties measured in laboratory experiments do not coincide with data of in situ conditions. Therefore, in situ thermal response test equipment has been developed and used in Canada, England, Germany, Norway, U.K., U.S.A. and Sweden to ensure precise designing of BTES systems. This paper describes the results and evaluations of the Adana continual thermal response test measurements. Copyright © 2007 John Wiley & Sons, Ltd. [source] Degradation of aramid fibers under alkaline and neutral conditions: Relations between the chemical characteristics and mechanical propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2010G. Derombise Abstract Aramid fibers are high-performance materials that have been used in various applications such as heat and cut protection, composites, rubber reinforcement, ropes and cables, and fabrics; today their use is proposed in geotextiles for alkaline ground reinforcement, and they have been used in cables for marine applications for a few years. However, there is a lack of experience with the long-term behavior of aramid fibers in wet and alkaline environments. Aging studies were therefore performed on Twaron 1000 fibers under different conditions (sea water, deionized water, pH 9, and pH 11). Hydrolytic degradation was evaluated with Fourier transform infrared and viscosimetry measurements, which were correlated with tensile test measurements. The tensile strength followed a logarithmic evolution with the aging time, whereas the modulus remained constant. A linear relation between the tensile strength and the reduced viscosity of the hydrolytically aged fibers is highlighted. Aging indicators are proposed that allow the hydrolytic degradation to be quantified. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Receiver operating characteristic surfaces in the presence of verification biasJOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES C (APPLIED STATISTICS), Issue 1 2008Yueh-Yun Chi Summary., In diagnostic medicine, the receiver operating characteristic (ROC) surface is one of the established tools for assessing the accuracy of a diagnostic test in discriminating three disease states, and the volume under the ROC surface has served as a summary index for diagnostic accuracy. In practice, the selection for definitive disease examination may be based on initial test measurements and induces verification bias in the assessment. We propose a non-parametric likelihood-based approach to construct the empirical ROC surface in the presence of differential verification, and to estimate the volume under the ROC surface. Estimators of the standard deviation are derived by both the Fisher information and the jackknife method, and their relative accuracy is evaluated in an extensive simulation study. The methodology is further extended to incorporate discrete baseline covariates in the selection process, and to compare the accuracy of a pair of diagnostic tests. We apply the proposed method to compare the diagnostic accuracy between mini-mental state examination and clinical evaluation of dementia, in discriminating between three disease states of Alzheimer's disease. [source] Efficient, large-scale archaeological prospection using a true three-dimensional ground-penetrating Radar Array systemARCHAEOLOGICAL PROSPECTION, Issue 3 2010Immo Trinks Abstract The Swedish UNESCO World Cultural Heritage site of the Birka and Hovgården Iron Age settlements is well suited for the testing of high-resolution archaeological prospection methods. In May 2006 ground-penetrating radar (GPR) and magnetometer test measurements were conducted at Birka, resulting in data of outstanding quality and new archaeological discoveries, but also demonstrating the need for increased spatial sampling regarding GPR prospection at complex Scandinavian sites. Therefore Birka was selected as a testing ground for a pilot study investigating the suitability of the novel multichannel GPR array system MIRA (MALÅ Imaging Radar Array) for efficient, large-scale GPR surveys with very dense spatial sampling. The study was conducted in May 2008 by MALÅ Geoscience AB in collaboration with the archaeological prospection unit of the Swedish National Heritage Board. The very high-resolution three-dimensional GPR pilot survey demonstrated that it is possible to survey 1,ha and more per day with 8,cm cross-line spacing, mapping archaeological structures in unprecedented resolution, such as postholes of only 25,cm diameter. This paper describes the tested technology and methodology as well as the fieldwork and the results of the study. Copyright © 2010 John Wiley & Sons, Ltd. [source] Prediction of intragranular strains in metallic polycrystals with a two-level homogenisation approach: Influence of dislocation microstructure on the mechanical behaviourPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2006D. Gloaguen Abstract A two-level homogenisation approach is applied to the micro-mechanical modelling of the elasto-plasticity of polycrystalline materials during various strain-path changes. The model is tested by simulating the development of intragranular strains during different complex loads. Mechanical tests measurements are used as a reference in order to validate the model. The anisotropy of plastic deformation in relation to the evolution of the dislocation structure is analysed. The results demonstrate the relevance of this approach for FCC polycrystals. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | |||||||||||||