Efficient material design for diesel particulate filters

This paper will give an overview about the filter development for diesel particulate emission control in automotive applications. The material development for passenger car diesel particulate filters led to new materials like silicon carbide while for heavy duty applications still Cordierite plays a major role. But in the future other materials might also be used for passenger cars. This paper will show the basic difference between both applications and describe the material design in terms of filter properties (base material, back pressure aspects, filtration efficiency, coating impact). Current application on vehicles with catalysed soot filters (CSF) with and without oxidation catalyst will be presented. Furthermore an outlook will be given on materials for catalysed soot filters for the future.     

"Nonspecific" chest pain associated with high long-term mortality: results from the primary prevention study in G?teborg, Sweden

BACKGROUND: The syndrome angina pectoris with effort-related chest pain or discomfort is usually easy to recognize. However, vague and nonspecific symptoms may cause little reason for extensive evaluation. The prognosis of such patients in the general population has so far not been well described. HYPOTHESIS: The study was undertaken to investigate long-term prognosis in men with chest pain considered to be nonspecific in comparison with men with typical angina pectoris (AP) or prior myocardial infarction (MI), and men without chest pain. METHODS: At the second screening of the G?teborg Primary Prevention Study in 1974-1977, 6,488 men aged 51 to 59 years at baseline were available for the present analysis. Men who had responded positively to a postal questionnaire about chest pain during exercise or at rest were interviewed by a physician according to a Rose questionnaire at the screening examination. Those with typical or probable AP were further examined by single experienced physician. The following four groups were formed: Group 1: men who did not complain of chest pain (n = 5,545). Group 2: men who had not consulted any doctor because of chest pain, but who had chest pain according to a questionnaire (n = 441); these men were not considered to have AP according to a three-step examination by experienced physicians. Group 3: typical AP (n = 232). Group 4: men who had suffered an MI (n = 134). RESULTS: During 16 years of follow-up, coronary heart disease (CHD) mortality for Groups 1-4 was 8.0, 19.5, 24.8, and 48.5%, respectively. Mortality from all cardiovascular diseases was 11.5, 24.5, 31.2, and 59.0%, respectively. Noncardiovascular disease mortality was 14.1, 17.7, 14.3, and 8.7%, respectively. Thus, the relative risk (RR) for CHD mortality among men with nonspecific chest pain (Group 2) was 2.77 [95% confidence interval (CI) 2.20, 3.50], for all cardiovascular disease mortality 2.46 (95% CI 2.00, 3.02), and for noncardiovascular disease mortality 1.60 (95% CI 1.28, 2.00). Total mortality in this group was as high (44%) as among those with typical AP (45%), but the highest mortality was found among men with a previous MI (68%). In men without chest pain it was 26%. Patients of Groups 2-4 had higher levels of cardiovascular risk factors than those in Group 1. Neither any specific questions in the Rose questionnaire, nor electrocardiographic changes at rest (uncommon) were of prognostic significance. Serum cholesterol, systolic blood pressure, diabetes, and smoking were significant predictors of outcome, both with respect to fatal CHD and to total mortality during the 16-year follow-up. CONCLUSION: We found a high cardiovascular as well as noncardiovascular mortality among patients with chest pain who had not been considered to have AP at a three-step examination procedure. It is important to be suspicious of early CHD symptoms in men (and women?) with "nonspecific" chest symptoms and to analyze their cardiovascular risk factor pattern further because they are at considerably higher risk for future events than those in whom CHD is not suspected.     

Experimental quadrotor flight performance using computationally efficient and recursively feasible linear model predictive control

A new linear model predictive control (MPC) algorithm in a state-space framework is presented based on the fusion of two past MPC control laws: steady-state optimal MPC (SSOMPC) and Laguerre optimal MPC (LOMPC). The new controller, SSLOMPC, is demonstrated to have improved feasibility, tracking performance and computation time than its predecessors. This is verified in both simulation and practical experimentation on a quadrotor unmanned air vehicle in an indoor motion-capture testbed. The performance of the control law is experimentally compared with proportional-integral-derivative (PID) and linear quadratic regulator (LQR) controllers in an unconstrained square manoeuvre. The use of soft control output and hard control input constraints is also examined in single and dual constrained manoeuvres.     

Gas–oil cracking activity of hydrothermally stable aluminosilicate mesostructures (MSU-S) assembled from zeolite seeds: Effect of the type of framework structure and porosity

Aluminosilicate mesostructures (MSU-S_BEA) assembled from zeolite Beta (BEA) seeds exhibited relatively high hydrothermal stability and were significantly more active in the cracking of gas–oil compared to MCM-41 after severe steaming pretreatment. The MSU-S_BEA mesoporous materials with wormhole framework structure and those having morphology of solid nanoparticles with high interparticle mesoporosity were more steam-stable and more active after severe steaming than those with hexagonal pore structure. Differences in acid sites strength between the MSU-S_BEA materials and MCM-41 could not be probed by the complex reaction system of the large hydrocarbon molecules of gas–oil.     

Chemical recycling of polymers from Waste Electric and Electronic Equipment

This research is focused on the recycling of three types of polymers, namely polycarbonate (PC), poly(acrylonitrile‐butadiene‐styrene) (PABS), and polystyrene (PS) from Waste Electric and Electronic Equipment (WEEE). Initially, the chemical structure of each polymeric material in a variety of WEEE was identified by Fourier Transform Infra Red (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). The potential recycling of these polymers from these wastes was examined by employing two different approaches, the dissolution/reprecipitation method and the more challenging technique of pyrolysis. During the first, the polymer is separated and recycled through a solvent/non‐solvent system. It is a simple and economic technique leading to high recovery of pure polymer. Both, model polymers and plastic parts from WEEEs were studied and optimum experimental conditions, including dissolution temperature and time, polymer concentration and type of solvent were proposed to achieve significant recovery of the polymer (>90 wt %). Furthermore, pyrolysis of waste Compact Disks (CD) was investigated and compared with model poly(bisphenol A carbonate) (PC) through a laboratory‐scale fixed bed reactor. The appropriate pyrolysis temperature was selected after measuring the thermal degradation of model PC by Thermogravimetric analysis (TGA). A large amount of oil was measured, together with a smaller amount of gaseous product, leaving also a solid residue. For both samples, the gaseous fraction consisted mainly of CO₂ and CO whereas in the liquid fraction a large amount of different phenolic compounds, including the monomer bisphenol A, was measured. It seems that recycling of used CDs by pyrolysis is a very promising technique having the potential of producing useful high‐value chemicals, which may find applications in the petrochemical industry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Antibacterial Surface Coatings from Zinc Oxide Nanoparticles Embedded in Poly(N‐isopropylacrylamide) Hydrogel Surface Layers

Despite multiple research approaches to prevent bacterial colonization on surfaces, device‐associated infections are currently responsible for about 50% of nosocomial infections in Europe and significantly increase health care costs, which demands development of advanced antibacterial surface coatings. Here, novel antimicrobial composite materials incorporating zinc oxide nanoparticles (ZnO NP) into biocompatible poly(N‐isopropylacrylamide) (PNIPAAm) hydrogel layers are prepared by mixing the PNIPAAm prepolymer with ZnO NP, followed by spin‐coating and photocrosslinking. Scanning electron microscopy (SEM) characterization of the composite film morphology reveals a homogeneous distribution of the ZnO NP throughout the film for every applied NP/polymer ratio. The optical properties of the embedded NP are not affected by the matrix as confirmed by UV‐vis spectroscopy. The nanocomposite films exhibit bactericidal behavior towards Escherichia coli (E. coli) for a ZnO concentration as low as ≈0.74 μg cm^?2 (1.33 mmol cm^?3), which is determined by inductively coupled plasma optical emission spectrometry. In contrast, the coatings are found to be non‐cytotoxic towards a mammalian cell line (NIH/3T3) at bactericidal loadings of ZnO over an extended period of seven days. The differential toxicity of the ZnO/hydrogel nanocomposite thin films between bacterial and cellular species qualifies them as promising candidates for novel biomedical device coatings.     

Correction to: Efficient Hardware Architectures for 1D- and MD-LSTM Networks

Journal of Signal Processing Systems -     

Multi‐stage adjustable robust optimization for process scheduling under uncertainty

Variations in parameters such as processing times, yields, and availability of materials and utilities can have a detrimental effect in the optimality and/or feasibility of an otherwise “optimal” production schedule. In this article, we propose a multi‐stage adjustable robust optimization approach to alleviate the risk from such operational uncertainties during scheduling decisions. We derive a novel robust counterpart of a deterministic scheduling model, and we show how to obey the observability and non‐anticipativity restrictions that are necessary for the resulting solution policy to be implementable in practice. We also develop decision‐dependent uncertainty sets to model the endogenous uncertainty that is inherently present in process scheduling applications. A computational study reveals that, given a chosen level of robustness, adjusting decisions to past parameter realizations leads to significant improvements, both in terms of worst‐case objective as well as objective in expectation, compared to the traditional robust scheduling approaches. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1646–1667, 2016