Ceramic Diesel Particulate Filters

Twenty-five years of diesel particulate filter (DPF) developments have shown that ceramic materials are well-suited candidates to fulfill the harsh requirements of exhaust after treatment. The introduction of DPF in passenger cars in Europe in 2000 was a real breakthrough from both a scientific and a commercial point of view. Different systems and filter materials can be used as DPF; however, at the moment silicon carbide wall flow filters seem to be at advantage. There is a continual demand for cost-effective and reliable materials and systems forced by increasing legal emission standards.     

Validating the Primary Care Posttraumatic Stress Disorder Screen and the Posttraumatic Stress Disorder Checklist with soldiers returning from combat.

The purpose of the research was to assess the diagnostic efficiency of the Primary Care Posttraumatic Stress Disorder Screen (PC-PTSD) and the Posttraumatic Stress Disorder Checklist (PCL) as clinical screening tools for active duty soldiers recently returned from a combat deployment. A secondary goal was to examine the item-level characteristics of both the PC-PTSD and the PCL. A validation study conducted with a sample of 352 service members showed that both the PC-PTSD and PCL had good diagnostic efficiency. The overall diagnostic efficiency assessed by the area under the curve (AUC) was virtually the same for both the PC-PTSD and PCL. The most efficient cutoff values for the PC-PTSD were either 2 or 3 "yes" responses with the latter favoring specificity. For the PCL, the most efficient cutoff values were between 30 and 34, mirroring recommended PCL cutoff values from some studies in primary care settings. The examination of item characteristics suggested a 4-item PCL with an AUC virtually identical to that of the full PCL. Item analyses also identified that the most discriminate item in both scales pertained to symptoms of avoidance. Implications and limitations are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An evaluation of the social perspective in the development oftechnical requirements

Uses a qualitative methodology to examine how discourse norms and socialization processes affect the development of technical requirements. Our exploratory investigation of how government personnel develop and review technical requirements indicates that discourse norms and academic technical writing socialization processes affect the technical writing process. Technical writers perceived that requirements in work statements became less precise as more requirements were coordinated in team-based designs. In essence, we found that, in team-based designs, interpretation conflict and technical diffusion were important dimensions when writing and coordinating technical requirements. Our findings suggest that collaborative technical writing is a complex and difficult process in team-based designs where integration and persuasion skills dominate     

Real Porous Media: Local Geometry and Transports

Our recent progress in the analysis and reconstruction of real porous media are surveyed and some emphasis is put on the two-field and on the grain reconstruction methods. Then, after a short summary of our previous analyses of transports, two recent developments are presented, namely, the determination of the resistivity index and of the dispersion tensor in multiphase flow.     

Amphiphilic behaviour of poly(glycidol)-based macromonomers and its influence on homo-polymerisation in water and in water/benzene mixture

The properties of amphiphilic polyether macromonomers and their behaviour during homo-polymerisation in water and in water/benzene mixture are reported. Homo-poly(glycidol) macromonomer bearing polymerisable p-vinyl benzyl end groups (PGl55-St) and two block poly(glycidol)-b-poly(glycidyl phenyl ether) macromonomers, containing polymerisable p-vinyl benzyl end groups attached to the hydrophobic (PGl52-b-PGlPhE8-St) or hydrophilic (PGlPhE9-b-PGl54-St) block were used for investigations. DLS measurements showed formation of micelles by all macromonomers, what is the reason for enhanced homo-polymerisation. In water the polymerisation initiated with 4,4′-azobis(4-cyanovaleric acid) was fast, while macromonomer conversion was over 90%. Introduction of benzene to the polymerisation system resulted in formation of swollen (less packed) micelles and to a decrease of the local concentration of double bonds in the micelle core. As a result the decrease of reaction rate followed by longer polymerisation time in case of PGl55-St and PGl52-b-PGlPhE8-St was observed. Nevertheless, their conversion remained high and varied from 95 to 10. In contrast for PGlPhE9-b-PGl54-St increase of polymerisation rate, accompanied by slight increase of conversion was observed for homo-polymerisation in water/benzene mixture.     

The early nineteenth century planning of Newcastle upon Tyne

This article seeks to re‐examine the social, political and economic factors involved in the redevelopment of central Newcastle between 1834–1840, and to suggest possible parallels with aspects of planning practice today. It emphasizes the contribution of the entrepreneur Richard Grainger and — utilizing the author's recent study — the architect John Dobson's possible advisory role. Using a number of previously unpublished maps and plans, earlier replanning schemes by Dobson and others are analysed in the context of the history and development of the town. In particular, attention is paid to ways in which these differed from, but may have influenced, the central area redevelopment scheme. This itself is assessed in terms of both the planning principles involved and its essentially commercial rationale, highlighted by details of the actual occupation of sites. Examination is also made of Grainger's relationship with the municipal authorities of the day and his financial methodology.     

Effect of gamma-irradiation on flavour 5′-nucleotides,tyrosine, and phenylalanine in mushrooms (Agaricus bisporus)

The impact of gamma-irradiation on 5′-nucleotides and on the free amino acids tyrosine and phenylalanine in fresh mushrooms was studied. After irradiation the samples were freeze-dried to avoid enzyme induced chemical changes. Three 5′-nucleotides could be detected using HPLC–UV and LC–ESI-MS: adenosine 5′-monophosphate (AMP), guanosine 5′-monophosphate (GMP) and guanosine 5′-diphosphate (GDP). Irradiation significantly reduced (p = 0.05) the GDP concentration (22%). AMP showed a marked reduction (46%) only at 5 kGy. GMP, tyrosine, and phenylalanine were not affected by gamma-irradiation.     

The effectiveness of producer‐side machine‐independent optimizations for mobile code

Portable mobile code is often executed by a host virtual machine using just‐in‐time compilation. In this context, the compilation time in the host virtual machine is critical. This compilation time can be reduced if optimizations are performed ahead‐of‐time before distribution of the mobile code. Unfortunately, the portable nature of mobile code limits ahead‐of‐time optimizations to those that are machine‐independent. This work examines the effect of machine‐independent optimizations on the performance of mobile code applications. All experiments use the SafeTSA Format, a mobile code format that is based on Static Single Assignment Form (SSA Form). The experiments, which are performed on both the PowerPC and IA32 architectures, indicate that the effects of performing classical machine‐independent optimizations are—in fact—quite machine‐dependent. Nevertheless, the results demonstrate that applying such optimizations in a mobile code system can be beneficial. Copyright © 2009 John Wiley & Sons, Ltd.     

Diffusion-controlled smoulder propagation in a composite slab

The steady propagation of a thin smouldering front parallel to the faces of a composite reactive slab has been considered. The slab consists of a double layer of solid with differing densities. As the smouldering front progresses into the solid it leaves behind an inert porous medium through which oxidizer is able to diffuse to the front. It is assumed that the reactive solid is sufficiently dense for no oxidizer to be present. The oxidizer concentration on one face of the slab is specified, the other being impervious to the transport of reactants. Dimensionless equations and boundary conditions are obtained for the concentration of oxidizer in the porous medium. These are solved to first order by use of a complex-variable method and a hodograph transformation giving the shape of the smouldering front for various parameter combinations. The analysis is extended to the case where the layers are of unequal thickness. Simple expressions for the shape of the front and the oxidizer concentration are obtained when one layer thickness is large. The model here considered is a first step in a more comprehensive analysis of smouldering in a non-uniform medium.