A quadratic boundedness approach to a neural network-based simultaneous estimation of actuator and sensor faults

Neural Computing and Applications - The paper is devoted to the problem of a neural network-based robust simultaneous actuator and sensor faults estimator design for the purpose of the fault...     

High Electrical and Thermal Conductivity Cast Al-Fe-Mg-Si Alloys with Ni Additions

Metallurgical and Materials Transactions A - Aluminum alloys with transition metals Fe and Ni show potential to form the basis for castable alloys with high electrical and thermal conductivity for...     

Online determination of transient thermal stresses in critical steam turbine components using a two-step algorithm

The article presents a novel algorithm for robust calculation of thermal stresses in steam turbine components during transient operating conditions. Stress calculations are performed in 2 steps: in the first step an unsteady radial temperature distribution in the component model is computed, and based on this thermal stresses at critical locations are determined in the second step. The radial temperature distribution is obtained by solving the Fourier-Kirchhoff equation for a cylinder or sphere by means of a finite difference method. The thermal stresses are computed using the Duhamel integral and Green functions evaluated with a constant heat transfer coe?cient and used with an equivalent steam temperature obtained from the surface heat flux.     

Evolutionary Algorithm Integrating Stress Heuristics for Truss Optimization

The optimal truss design using problem-oriented evolutionary algorithm is presented in the paper. The minimum weight structures subjected to stress and displacement constraints are searched. The discrete design variables are areas of members, selected from catalogues of available sections. The integration of the problem specific knowledge into the optimization procedure is proposed. The heuristic rules based on the concept of fully stressed design are introduced through special genetic operators, which use the information concerning the stress distribution of structural members. Moreover, approximated solutions obtained by deterministic, sequential discrete optimization methods are inserted into the initial population. The obtained hybrid evolutionary algorithm is specialized for truss design. Benchmark problems are calculated in numerical examples. The knowledge about the problem integrated into the evolutionary algorithm can enhance considerably the effectiveness of the approach and improve significantly the convergence rate and the quality of the results. The advantages and drawbacks of the proposed method are discussed.     

PET短纤维和长丝：生产工艺的发展趋势

聚酯短纤维和长丝的消费不断增长，这给商业增长提供了巨大的机会，但同时，世界范围的竞争日趋激烈。今天为了保持市场竞争力，作出正确决定变得越来越重要。本文的目的是从技术角度剖析赢得经济挑战的一些基本因素。     

Rohdichtebestimmung von Holzwerkstoffen mittels Computertomographie

In this work the vertical density profiles of three different commercial wood based panels (particleboard, MDF, OSB) were investigated using a conventional X-ray method as well as an industrial computer tomography (CT) method. The reconstructed gray level images of the obtained CT data were used to calculate a standardized density profile of each panel. The results showed that the measured (X-ray) and the calculated (CT) density profiles of the panels fit well in the core layer of the boards; in the most outer surface layers some anomalies in the results can occur in both methods. The advantage in the implementation and evaluation of the more complicated CT measurement compared to the conventional X-ray procedure is the three-dimensional data structure and the opportunity to do appropriate structural analysis of the investigated wood based panels.     

Characterization of catalysts obtained from rapidly quenched alloy precursors by electrochemical/chemical processes of material degradation—selected examples

Rapidly quenched amorphous alloys—containing metallic or metalloid elements—are precursors for selective catalysts of many technically important reactions. To increase their activity, various methods of material degradation occurring at the surface and in the bulk of the rapidly quenched alloys have been used for promoting the catalytic performance of such materials. The modifications of the structure, composition, and morphology of the substrate proved to be efficient in transforming inactive metal alloy precursors into active and selective catalysts for hydrogenation, and dehydrogenation of organic compounds, as well as for other processes like steam reforming of methanol. This article presents several examples of characterization of such catalysts and discusses their selectivity and activity in a connection with physical and chemical properties of their surfaces. Moreover, it is shown that scanning electron microscopy, Auger electron spectroscopy, scanning Auger microscopy, and energy dispersive spectrometry allowed the local changes occurring during the activation process to be identified and their implications for catalytic function to be considered.