Specifics of initial steam condensation and its influence on corrosion damage in turbines

Processes of corrosion cracking of the metal of turbine blades in the region of initial steam condensation are considered. Possible ways of preventing corrosion-fatigue damage to the blades are proposed.     

Diagnostics of the Condition of the Flow-Through Part of High-Pressure and Intermediate-Pressure Cylinders by Running Measurements of Steam Pressure and Temperature in a Turbine

A method for diagnosing mechanical damage and wear of the blade system and the shroud, diaphragm, and end seals is presented. The method is based on the use of the readings of devices for scheduled control of the steam temperature and pressure at the outlet from the cylinders, in the extracted steam, and in the first shoulders of the end seals. Results of practical application of the method at electric power plants including those equipped with data-processing equipment are presented. The introduction of the suggested monitoring will make it possible to pass from scheduled repair to determining the repair time proceeding from the actual condition of the turbine.     

在几何结构设计中采用遗传算法优化横向磁场永磁电机的转矩波形

在制造横向磁场永磁电机（TFPM）电机之前，应确定最大转矩的波形。通过调整TFPM电机的各项几何参数，可以使电机达到其最大转矩。一种基于人工智能的最优化方法可以使得每个极间隔都获得理想的转矩波形。本文给出了一种用于优化TFPM几何参数的遗传算法，该算法同样适用于其它结构的电机。     

A model for teletraffic performance and channel holding timecharacterization in wireless cellular communication with general sessionand dwell time distributions

Channel holding times and user mobility are important topics in the study of wireless cellular communications. We present an approach to modeling user mobility and session time which enables both the calculation of teletraffic performance characteristics and a characterization of holding time which agrees with published reports. The model allows both the dwell time and unencumbered session time to have general distributions. A derivation of the channel holding time distribution is given. We then show how the model's parameters can be chosen to fit empirical data including observations of channel holding time     

Effect of the composition of an oxide coating and the preparation method of block catalysts on their activity in the deep oxidation of methane

Deep methane oxidation catalysts containing 3d metal (Mn, Co), rare-earth (La) and alkali-earth (Ba, Sr) oxides in the porous matrices of secondary supports (Al₂O₃, ZrO₂, and their binary composition) formed on honeycomb blocks (cordierite, kaolin-aerosil) are studied by means of X-ray powder diffraction, the thermal desorption of nitrogen, and temperature-programmed reduction with hydrogen. It is shown that the activity and stability of the catalysts depend on the method for their preparation and the nature of the active components and secondary and block supports. After life cycle tests, the proposed catalysts with 80–100% conversion of methane into CO₂ at temperatures of 650–750°C can be recommended for use in systems for the catalytic purification of gases containing hydrocarbon admixtures (methane and C₂–C₄ homologues) and the combustion of hydrocarbon fuels in industrial and household catalytic heat generators.     

Scalability in Global Mobile Information Systems (GloMo): Issues,Evaluation Methodology and Experiences

The GloMo (Global Mobile Information Systems) project¹ has focused on developing new wireless ad hoc networking technologies. These new technologies rely on a broad and varied set of techniques to help cope with the problems inherent in the wireless environment. One of the most critical design elements of all the various technologies is their applicability in large scale deployments. The main objective of our work is to develop and implement a simulation methodology to help evaluate the scalability of these new ad hoc networking technologies and gain some insight into the various aspects of ad hoc network performance scalability issues. To achieve that we have developed a scalability performance evaluation framework and plan, that spans all the various dimensions of scalability: size (number of nodes and density), traffic, operational environment (i.e. propagation models, terrain etc.), mobility. For demonstration purposes we have applied this process on a representative integrated protocol suite designed to provide communication services in mobile ad hoc wireless networks. The corresponding results of the two most critical aspects of scalability properties in tactical networks (i.e. network initialization time and traffic scalability) are also presented here, and demonstrate that a very extensive evaluation of the corresponding scalability metrics under a combination of the various scalability dimensions defined in this paper, is necessary in order to provide an in-depth analysis of the scalability properties in wireless mobile ad hoc networking environments.     

Low-cost measures helping to make the operating turbines at thermal and nuclear power stations more reliable and efficient

Measures aimed at making steam turbines more economically efficient, reliable, and suitable for repair, and at increasing their available power output through reducing abrasive and drop impingement erosion of blades and improving the vacuum tightness, modernization, and monitoring of the labyrinth seals are proposed.     

Simulation and Experimental Validation of Spacer Fabrics Based on their Structure and Yarn’s Properties

Warp-knitted spacer fabrics are considered, which are plates or shells composed of two knitted plane layers connected by vertical beams. Our aim is to compute the effective stiffness and permeability of such spacer fabrics on the basis of their structure and properties of yarns and the monofil. In order to reduce the computational effort and simplify the computational model, homogenization and dimension reduction techniques are applied. They replace the fabric by an equivalent two-dimensional plate or shell with effective elastic properties. To compute the effective permeability, the fluid simulation is done on the fully resolved micro-structure. The paper demonstrates the algorithm on application examples. We compute the elastic properties of a spacer fabric and its effective permeability for different outer-plane compression stages. Numerical examples were performed by applying the multi-scale simulation tools, developed at Fraunhofer ITWM and by comparing with the corresponding experimental results, based on measurements performed at the TU Dresden. The developed algorithms and simulation tools enable a full virtualisation of the material design adapted to exposure scenarios in various technical application cases, i.e. infiltration processes with polymers in the field of fiber reinforced composites, which enables new discoveries for the designing and manufacturing process of 3D warp-knitted spacer fabrics.     

Wet-steam erosion of steam turbine disks and shafts

A study of wet-steam erosion of the disks and the rotor bosses or housings of turbines in thermal and nuclear power plants shows that the rate of wear does not depend on the diagrammed degree of moisture, but is determined by moisture condensing on the surfaces of the diaphragms and steam inlet components. Renovating the diaphragm seals as an assembly with condensate removal provides a manifold reduction in the erosion.