A study of the use of concept selection methods from inside a company

Design methods have been studied by researchers for decades. Academia considers their impact on industry to be insufficient. The objective of this research is to understand the use and impact of design methods in the context of a specific company, Volvo Car Corporation (VCC), by describing the behaviour of engineers in relation to methods, to assist in the future development of design methods and tools. We mainly concentrate on concept selection methods because of their relevance in this company. The data presented is the result of qualitative research carried out during 4 years at VCC, where the authors were located as researchers. The research shows that many methods are employed besides those with an academic name, that some in-company methods used contain improvements to methods researched by academia, that some modifications to academic methods lead to unreliable results, and that there is a lack of objectivity in method modification. For these reasons, the authors suggest further research on understanding the principles of successful and unreliable modification of concept selection methods.     

Envelope computation in the plane by approximate implicitization

Given a rational family of planar rational curves in a certain region of interest, we are interested in computing an implicit representation of the envelope. The points of the envelope correspond to the zero set of a function (which represents the envelope condition) in the parameter space combining the curve parameter and the motion parameter. We analyze the connection of this function to the implicit equation of the envelope. This connection enables us to use approximate implicitization for computing the (exact or approximate) implicit representation of the envelope. Based on these results, we formulate an algorithm for computing a piecewise algebraic approximation of low degree and illustrate its performance by several examples.     

Decoration of single-walled carbon nanotubes with Pt nanoparticles from an organometallic precursor

Carbon nanotubes (CNTs) are nanomaterials of high interest due to their unique structural, electrical, and mechanical properties. Carbon materials have been widely employed to support metallic nanoparticles for catalysis and electrochemical applications. In this work, we investigated the synthesis of platinum nanoparticles generated from the complex Pt₂(dba)₃ (tris(dibenzylideneacetone) diplatinum) and stabilized with a long alkyl chain amine, hexadecylamine (HDA) and supported on functionalized single-walled carbon nanotubes (SWCNTs). High resolution transmission electron microscopy (HRTEM) studies revealed isolated Pt nanoparticles (2?C3 nm) on SWCNTs. Powder X-ray diffraction (XRD) was used to assess the structure of Pt nanoparticles dispersed on SWCNTs assigned to Pt face-centered cubic (fcc). Additionally, infrared Fourier transform spectroscopy confirmed the presence of the stabilizer at the surface of the Pt nanoparticles even after the purification step and functional groups at the surface of pre-treated SWCNTs. This synthetic method may be an alternative route to prepare small size Pt nanoparticles supported on functionalized SWCNTs.     

Effect on the journal impact factor of the number and document type of citing records: a wide-scale study

We studied the effect on journal impact factors (JIF) of citations from documents labeled as articles and reviews (usually peer reviewed) versus citations coming from other documents. In addition, we studied the effect on JIF of the number of citing records. This number is usually different from the number of citations. We selected a set of 700 journals indexed in the SCI section of JCR that receive a low number of citations. The reason for this choice is that in these instances some citations may have a greater impact on the JIF than in more highly-cited journals. After excluding some journals for different reasons, our sample consisted of 674 journals. We obtained data on citations that contributed to the JIF for the years 1998?C2006. In general, we found that most journals obtained citations that contribute to the impact factor from documents labeled as articles and reviews. In addition, in most of journals the ratio between citations that contributed to the impact factor and citing records was greater than 80% in all years. Thus, in general, we did not find evidence that citations that contributed to the impact factor were dependent on non-peer reviewed documents or only a few citing records.     

Design of a Calibration System for Heat Flux Meters

Accurate heat flux measurements are needed to gain a better knowledge of the thermal performance of buildings and to evaluate the heat exchange among various parts of a building envelope. Heat flux meters (HFMs) are commonly used both in laboratory applications and in situ for measuring one-dimensional heat fluxes and, thus, estimating the thermal transmittance of material samples and existing buildings components. Building applications often requires heat flux measurements below 100 W · m^?2. However, a standard reference system generating such a low heat flux is available only in a few national metrology institutes (NMIs). In this work, a numerical study aimed at designing an HFM calibration apparatus operating in the heat flux range from 5 W·m^?2 to 100 W · m^?2 is presented. Predictions about the metrological performance of such a calibration system were estimated by numerical modeling exploiting a commercial FEM code (COMSOL^®). On the basis of the modeling results, an engineered design of such an apparatus was developed and discussed in detail. The system was designed for two different purposes: (i) for measuring the thermal conductivity of insulators and (ii) for calibrating an HFM with an absolute method (i.e., by measuring the applied power from the heater and its active cross section) or by a relative method (i.e., by measuring the temperature drop across a reference material of known thickness and thermal conductivity). The numerical investigations show that in order to minimize the uncertainty of the generated heat flux, a fine temperature control on the thermal guard is needed. The predicted standard uncertainty is within 2% at 10W·m^?2 and within 0.5% at 100 W · m^?2.     

基于EBSD的金属变形激活滑移系的确定方法

针对多晶金属力学变形过程中的激活滑移系,提出了一种基于电子背散射衍射(Electron Back-Scatter Diffraction,EBSD)技术的滑移系确定方法。借助材料表面晶体取向和滑移带形貌分析,计算并测量滑移带与加载应力轴之间的夹角,通过两者比较确定滑移面;计算该滑移面对应的可能滑移系的Schmid因子,根据Schmid定律确定滑移方向,从而判断实际被激活滑移系。以奥氏体不锈钢为例,试验证实了该方法的可行性。与其他方法相比,该方法可获得表面损伤形貌及其晶体取向分布,更适用于多晶材料力学变形后的滑移系分析。     

氯元素对高炉冶炼的影响分析及展望

在分析高炉内氯元素的主要来源和相关化学反应的基础上,综述了氯对高炉炉料、耐火材料、风口以及设备的影响。指出氯元素对高炉原燃料的作用机理,提出降低氯元素对高炉耐火材料侵蚀的措施,寻找有效降低净煤气中氯含量的方法,以及研究氯元素在高炉渣铁形成过程中的分配规律,指出找到适宜的高炉渣排氯的操作条件是今后研究的重点,可为降低氯元素对高炉冶炼过程的影响提供理论依据。     

高炉冶炼钒钛矿过程中炉缸沉积物的形成原因

高炉冶炼钒钛矿时炉缸会产生大量的沉积物,影响高炉正常生产。对炉缸沉积物进行了检测,对高炉渣的冶金性能进行了试验研究,结果表明:沉积物的成分复杂,其中一些沉积物的铝、硅含量较大;沉积物形成的主要来源为TiC包裹金属铁的沉降聚集,渣铁对耐火材料的侵蚀,含高熔点物质的高黏度炉渣在炉底堆积。高铝中钛渣的黏度过大,炉渣碳含量较高是导致沉积物形成的主要原因,因此,改善高铝中钛渣的冶金性能可以有效抑制沉积物的形成。