Influence of heating rate on the pyrolysis of oil shale

The decomposition of oil shale from the Kvarntorp deposit in Sweden has been investigated using isothermal and non-isothermal methods. It was found that the heating rate during the initial non-isothermal period in the isothermal experiments had a considerable effect on the rate of devolatilization. At heating rates in the order of 10⁵°C/s the total weight loss exceeded the weight loss predicted from the volatile matter according to a proximate analysis.The effect of particle and sample size on the rate of decomposition (weight loss) was studied and found to have a significant influence at heating rates of the order of 10⁵°C/s while no effect was detected at heating rates around 200 °C/s (isothermal) or below 50°C/min (non-isothermal). The decomposition at low heating rates was completed at temperatures below 600°C and about 50 percent of the devolatilization could be described by first order kinetics with an apparent activation energy of 130 KJ/mole.At heating rates of 200°C/s (isothermal) the decomposition could also be described by simple first order kinetics but with an activation energy of 67 KJ/mole, thus indicating a different rate-determining mechanism.     

Naphtali-Sandholm distillation calculations for NGL mixtures near the critical region

Multicomponent distillation calcultions are carried out using a modification of the Naphtali-Sandholm column calcultaion procedure coupled with the Soave-Redlich-Kwong equation of state for generating K-values and enthalpies.

The modified Naphtali-Sandholm procedure is applicable when the individual stage efficiencies are unity and the K-values are not strongly dependent on the vapour-phase composition. For a column with M components and N stages, N(M + 2) relationships are set up.

The N(M + 2) equations are solved using Newton-Raphson iteration with imposed maximum allowable changes of the independent variables between iterations. Analytical derivatives of the K-values and enthalpies with respect to composition and temperature are employed in the Jacobian.

The method has been used for the process development and design of distillation columns associated with the separation of natural gas liquids (NGL). Fast and safe convergence is obtained even near the critical region.     

Creating robust high-throughput traffic sign detectors using centre-surround HOG statistics

In this paper, we detail a system for creating object detectors which meet the extreme demands of real-world traffic sign detection applications such as GPS map making and real-time in-car traffic sign detection. The resulting detectors are designed to detect and locate multiple traffic sign types in high-definition video (high throughput) from several cameras captured along thousands of kilometers of road with minimal false-positives and detection rates in excess of 99%. This allows for the accurate detection and location of traffic signs in geo-tagged video datasets of entire national road networks in reasonable time using only moderate computing infrastructure. A key to the success of the methods described in this paper is the use of extremely efficient classifier features. In this paper, we identify two obstacles to achieving the desired performance for all target traffic sign types, feature memory bandwidth requirements and feature discriminance. We introduce our use of centre-surround histogram of oriented gradient (HOG) statistics which greatly reduce the per-feature memory bandwidth requirements. Subsequently we extend our use of centre-surround HOG statistics to the color domain, raising the discriminant power of the final classifiers for more challenging sign types.     

Robuste multikriterielle Dienstkomposition in Informationssystemen

Service compositions are used to implement business processes in a variety of application domains. A quality of service (QoS)-aware selection of the service to be composed involves multiple, usually conflicting and possibly uncertain QoS attributes. A multi-criteria solution approach is desired to generate a set of alternative service selections. In addition, the uncertainty of QoS-attributes is neglected in existing solution approaches. Hence, the need for service reconfigurations is imposed to avoid the violation of QoS restrictions. The researched problem is NP-hard. This article presents a heuristic multi-criteria service selection approach that is designed to determine a Pareto frontier of alternative service selections in a reasonable amount of time. Taking into account the uncertainty of response times, the obtained service selections are robust with respect to the constrained execution time. The proposed solution approach is based on the Non-dominated Sorting Genetic Algorithm (NSGA)-II extended by heuristics that exploit problem specific characteristics of the QoS-aware service selection. The applicability of the solution approach is demonstrated by a simulation study.     

A survey of semiconductor supply chain models part I: semiconductor supply chains,strategic network design,and supply chain simulation

Supply chain management issues have become increasingly important to the semiconductor industry over the last two decades due to the global distribution of facilities and increasing numbers of firms specialising in particular stages. This series of three papers reviews the literature on modelling and analysis of the larger semiconductor supply chain. After describing the structure of semiconductor supply chains to provide context for the research efforts, we propose a classification scheme for the relevant literature. The remainder of this paper (Part I) then focuses on Strategic Network Design models for this industry, supply chain coordination through contracting and semiconductor supply chain simulation. Part II discusses Demand Planning, Inventory Management and Capacity Planning, while Part III addresses Master Planning, Production Planning and Demand Fulfilment.     

Time efficiency and physical workload in manual picking from large containers

A common task in both trade and manufacturing, manual picking from large containers often involves considerable physical workload, as well as low efficiency and varying picking times. With quantitative evidence from an industrial setting, the paper provides detailed insights into how physical workload and picking time vary in picking from large containers. Components at a short horizontal distance from the picker and at the top instead of the bottom of the pallet are associated with shorter picking time and lower physical workload. Moreover, pallets tilted 45° towards the picker are associated with picking times that are significantly shorter on average and display smaller variations than horizontal pallets. The effects that the tilting of the pallets has on physical workload differs depending on component characteristics and from which section of the containers picking was performed. In the study, the greatest values of physical workload were observed for the tilted pallets.     

Phase Selection in Mn–Si Alloys by Fast Solid-State Reaction with Enhanced Skyrmion Stability

B20-type transition-metal silicides or germanides are noncentrosymmetric materials hosting magnetic skyrmions, which are promising information carriers in spintronic devices. The prerequisite is to prepare thin films on technology-relevant substrates with magnetic skyrmions stabilized at a broad temperature and magnetic-field working window. A canonical example is the B20-MnSi film grown on Si substrates. However, the as-yet unavoidable contamination with MnSi_1.7 occurs due to the lower nucleation temperature of this phase. In this work, a simple and efficient method to overcome this problem and prepare single-phase MnSi films on Si substrates is reported. It is based on the millisecond reaction between metallic Mn and Si using flash-lamp annealing (FLA). By controlling the FLA energy density, single-phase MnSi or MnSi_1.7 or their mixture can be grown at will. Compared with bulk MnSi, the prepared MnSi films show an increased Curie temperature of up to 41 K. In particular, the magnetic skyrmions are stable over a much wider temperature and magnetic-field range than reported previously. The results constitute a novel phase selection approach for alloys and can help to enhance specific functional properties, such as the stability of magnetic skyrmions.