Establishment of accuracy limits and standards for comparative thermal conductivity measurements

New techniques have been developed for reducing thermal conductivity data from thermal comparative measurements. The first of these techniques is based on making a Taylor-series expansion of the stack centerline temperature profile. The result is an expression giving the ratio of sample to reference conductivities at any temperature as a function of measured quantities, the stack thermocouple readings and stack element thicknesses. The conventional formula presently used to reduce comparative conductivity data is shown to be a special result of the general analysis. A second technique involves the use of linear least-squares (LS) techniques to derive both the sample and the reference conductivities from the measured data. The LS technique provides the coefficients for a polynomial temperature expansion of the reference and sample conductivities directly. Use of the new techniques is illustrated in a reduction of some comparative data on the conductivities of Pyrex 7740 and Pyroceram 9606. It is shown that a highly self-consistent pair of conductivity functions can be derived for these two commonly used reference materials if the conductivity vs temperature relation for Pyrex is modified slightly from its recommended value. The Pyroceram conductivity results from the comparative measurements are in good agreement with a conductivity derived from pulse diffusivity and differential scanning calorimetry measurements and also in good agreement with the recommended Pyroceram conductivity function.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

基于盲数理论的关键块体稳定性分析研究

针对运用块体理论分析岩质边坡稳定性问题存在多种不确定性的混合体,提出用盲数表达具有不确定性的计算参数,将盲数理论引入楔形关键块体稳定计算方法中,给出了一种安全系数的计算方法.通过盲数运算可得到安全系数在不同取值区间内的可信度,较好地减少了因取单一值计算结果中主观因素的影响.实例研究结果表明,该方法方便灵活、有效、实用、计算结果较为可靠、合理.     

A reference model for team-enabled workflow management systems

Today's workflow systems assume that each work item is executed by a single worker. From the viewpoint of the system, a worker with the proper qualifications selects a work item, executes the associated work, and reports the result. There is usually no support for teams, i.e., groups of people collaborating by jointly executing work items (e.g., the program committee of a conference, the management team of a company, a working group, and the board of directors). In this paper, we propose the addition of a team concept to today's workflow management systems. Clearly, this involves a marriage of workflow and groupware technology. To shed light on the introduction of teams, we extend the traditional organizational meta model with teams and propose a team-enabled workflow reference model. For this reference model and to express constraints with respect to the distribution of work to teams, we use object constraint language (OCL).     

泄水闸闸基抗滑稳定分析有限元计算

广西柳江红花水利柜纽泄水闸闸基存在较多的泥化夹层及节理面，影响闸基的稳定。采用非线性平面有限元计算，分析部基应力状态，研究闸基抗滑稳定问题。计算得出闸基下泥化夹层、节理面上单元的抗滑安全系数，可滑动通道上泥化夹层、节理面的抗滑系数及闸基材料强度储备系数，为闸基抗滑稳定分析提供参考，得出闸基稳定、无需进行特殊措施工程处理的结论。     

A Token Based Graphics System

This paper presents the design of a novel process oriented graphics systems architecture suitable for emulating many general purpose computer graphics systems. The systems architecture has been designed loosely on the actor model of computation, and consists of a number of functionally distinct modules or processes, which communicate solely by token (message) passing. The design addresses a specific requirement for configurability and adaptability of and between modules identified within interactive computer graphics systems.     

Near-infrared spectroscopic analysis of macronutrients and energy in homogenized meals

Near-infrared (NIR) reflectance spectroscopy was evaluated as a rapid and environmentally benign technique for the simultaneous determination of macronutrients and energy in commercially available, packaged meals. Reflectance spectra (400–2498 nm) of homogenized meals were obtained with a dispersive NIR spectrometer. Protein and moisture were measured by AOAC reference methods, total fat by a semi-automated acid hydrolysis, solvent extraction, gravimetric method and total carbohydrate calculated. Energy was calculated using Atwater factors. Using multivariate analysis software, PLS models (n = 113–115 products) were developed to relate NIR spectra of homogenized meals to the corresponding reference values. The models predicted components and energy in validation samples (n = 37–38 products), overall, with r² of above 0.96. Ratios of deviation to performance were between 3.6 and 6.6, and indicated adequacy of the models for screening, quality control, or process control. Performance of the models varied substantially when used to predict sub-groups of meals within the validation set.     

网状阳极系统技术标准讨论

提供了网状阳极材料选用参数、设计依据、安装步骤以及调试、验收要求。制定的阳极网接地电阻计算公式,为电源设备选型提供了依据。指出了设计阳极网及电缆选用应遵循的原则,为广大设计人员提供了参考标准。     

Online measurement of water content in candidate reference materials by acousto-optical tuneable filter near-infrared spectrometry (AOTF-NIR) using pork meat calibrants controlled by Karl Fischer titration

Certified reference materials (CRMs) are prepared from a wide variety of matrices. Water removal is an excellent way of achieving increased matrix lifetime and hence CRM stability. High-speed acousto-optical tuneable filter near-infrared spectrometry (AOTF-NIR) has been implemented for measurement of water content in powder matrix reference materials in amber glass vials. Almost 50,000 spectra were collected from 1300 to 2100 nm with a 2 nm increment for powders of meat, rye grass, potato, cotton seed and sugar beet. The AOTF-NIR instrument was placed in a capping machine, with a measurement frequency of 10–15 vials/min and a trigger signal for reproducible collection of spectra. The calibrants comprised 19 pork meat powder samples equilibrated with different hygrostatic solutions or subjected to oven drying to achieve different water concentrations. Mixtures of powders with different water content were also prepared in order to obtain a calibration range from 0.5 to 8.3% water (m/m). All calibration samples were measured by volumetric Karl Fischer titration (V-KFT), accredited under ISO 17025. The calibrants were then measured by AOTF-NIR together with the samples. Multiplicative scatter correction (MSC) was applied to the absorbance spectra in order to correct for the scattering of light in the different powders and scattering effects from the vials. A partial least squares regression model (PLS) based on two principal components was created and applied for prediction of water content in the samples with a standard error of 0.5% water (m/m).     

Athletic classmates, physical self-concept, and free-time physical activity: A longitudinal study of frame of reference effects.

The systematic analysis of factors that promote or impede physical activity in children is an urgent task for educational researchers. The present study investigated the reciprocal relationship between physical self-concept, teacher-assigned grades in physical education classes, and free-time physical activity, and analyzed positive and negative consequences of being in a class with high class-average physical ability. Data from a large, representative sample of 1,095 preadolescents from 66 classrooms were examined within a longitudinal framework. Multilevel analyses showed that membership in a class with high class-average physical ability was associated with lower physical self-concept and free-time physical activity and highlighted the significant role of teacher-assigned grades in the development of physical self-concept and physical activity. Furthermore, as predicted, there were positive reciprocal effects between physical self-concept and physical activity levels. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The accuracy of reference lists in five experimental psychology journals.

Reference lists appended to published journals are of critical importance to readers of academic literature. They allow readers to retrieve cited sources, either to increase their own knowledge or to substantiate the authors' claims, and in so doing help to establish the judgment and credibility of the authors (M. F. McLellan et al, 1992). However, erroneous references detract from the intended function of reference lists by impeding retrieval searches and by providing misleading bibliographic information (G. de Lacey et al, 1985; McLellan et al, 1992). The present study aims to assess the accuracy of reference lists in five experimental psychology journals published by the American Psychological Association (APA) in 1999 (Journal of Experimental Psychology: Animal Behavior Processes, Journal of Experimental Psychology: Applied, Journal of Experimental Psychology: Learning, Memory, and Cognition, Journal of Experimental Psychology: Human Perception and Performance, and Journal of Experimental Psychology: General). Perhaps the most disturbing result from this study is the finding that authors were incorrectly cited in 12% of reference list citations, with errors in the initials of the authors being the most common. (PsycINFO Database Record (c) 2010 APA, all rights reserved)