EFFECT OF RELATIVE SLIP AMPLITUDE ON FRETTING FATIGUE OF HIGH STRENGTH STEEL

Abstract— The effect of relative slip amplitude on fretting fatigue in high strength steel was studied at various contact pressures using fretting pads of various lengths. Under a given contact pressure, the fretting fatigue life showed a minimum at a certain relative slip amplitude. Under a fixed pad length, the life also showed a minimum at a certain contact pressure. A map of fretting fatigue life versus contact pressure and relative slip amplitude was obtained using the data of this study. The map indicated that both the phenomena which showed a minimum life in relation to slip dependence and contact pressure dependence were the same, as were the underlying mechanisms. The minimum life was interpreted in terms of local stress concentration at the fretted area.     

Analysis of temperature effects near mode I cracks in glassy polymers

A previous isothermal study (Estevez et al., Journal of Mechanics and Physics of Solids 48, 2585–2617, 2000) has shown that the toughness of glassy polymers is governed by the competition between shear yielding and crazing. The present work aims at investigating loading rates for which thermal effects need to be accounted for. The influence of the heat coming from the viscoplastic shear yielding and from crazing on their competition and on the toughness is examined. Crazing is shown to be the dominant heat source, and the dependence of the craze properties on temperature appears to be key in controlling the toughness of the material.*Author for correspondence (E-mail: rafael.estevez@insa-lyon.fr)     

Buffers and backup machines in automatic transfer lines

Buffer storage of the work-in-process inventory, decouples successive stages of automatic transfer production lines, assuring partial operability under machine failure. Certain special features such as secondary (standby) machines, special maintenance and diagnostic systems can lengtben the uptime or shorten the downtime of individual stages. When special features for K stages and spaces for M buffers are available, it is of great interest to system designers to know which stages should have the special features and where the buffer spaces should be inserted to maximize the line output rate. This paper addresses itself to such design problems. A bivariate dynamic programming procedure is developed which provides a layout for the buffers and an allocation of special features, maximizing the line output rate as defined by Buzacott (1967, 1968). The Buzacott formula is based on a heuristic argument which provides, in general, an upper bound on the true system output rate.     

THE TEMPERATURE OF BURNING CARBON PARTICLES IN A FAST FLUIDIZED BED OF FINE PARTICLES

The temperature of coarse (6–8 mm) carbon particles burning in a fast fluidized bed was measured. The burning carbon particle was found to be 50–70^°C hotter than the bed solids. The convective heat transfer coefficient on the particle was also measured in a separate experiment to help predict the temperature of the carbon particle using a mathematical model which considered both combustion kinetics and heat transfer on the particle. A good agreement between the predicted and measured values of temperature was found.     

汉英词语对齐规范

该文介绍了一个新的汉英词语对齐规范。该规范以现有的LDC汉英词语对齐规范为基础,对其进行了较大的改进和扩展,特别是提出了一种全新的对齐标注方法 —— 将词语对齐区分为真对齐和伪对齐,真对齐又分为强对齐和弱对齐。这种细化的标注方法能够更好地刻画词语对齐的特点。该规范已经实际应用于大规模的人工词语对齐标注中。我们对对齐标注的一致性进行了评价。结果表明,在该规范的指导下,标注者内部和标注者间的对齐都取得了比较理想的一致性,两组强、弱、伪三种对齐的Kappa值分别为0.99、0.98、0.93 和0.96、0.83、0.68。最后,一个简单的实验初步证实了该规范在统计机器翻译中的有效性。     

ROUGH FINITE-STATE AUTOMATA

The concept of a rough finite-state semi-automaton, in which the result of any transition is a rough set of states, is formulated and then extended to that of a rough finite-state automaton by adding the set of accepting states. The behavior of such an automaton is defined and turns out to be a rough set of input words.     

An expert system based approach to manufacturing cell design

The design of cellular systems is a complex, multi-criteria and multi-step process which can have significant implications for the entire organization. Most research in this area focuses on the formation of pan families and associated machine groups, one step in the cell design process. Numerous quantitative techniques have been developed to address this part-family/machine group formation problem. Existing approaches include math programming, algorithms for matrix diagonalization, the application of network modelling and the use of similarity coefficients. These mathematically-oriented techniques can handle a relatively limited set of quantitative objectives and. in addition, require many simplifying assumptions. For this reason, the solutions generated by these techniques are of limited usefulness in actual cell design. This paper proposes an expert system approach to cell system design. The starting point for the expert system is the initial solution generated by traditional mathematical techniques. Based on a flexible set of user-driven quantitative and qualitative factors, the expert system evaluates these preliminary solutions for feasibility and quality. If the solutions are not satisfactory (infeasible or of low quality), the system suggests modifications.     

Sequential control of a monetary policy model for India

This paper attempts to incorporate expectation generating mechanisms in a formal economic planning model. We have tried to introduce a simple bayesian filter method into an econometric model to see how the system parameters would change subject to a ‘policy-optimization-process’. The method was applied to a monetary policy model for India to see how the political authorities would react to private sector reactions to the policy-optimization-process. Through continuous updating of the response parameters, we can derive a very different type of monetary-fiscal policy structure than that which can be obtained through the usual optimal control process.     

A Geosat-derived noise spectrum for detecting seamounts in the Arabian Sea

Abstract

Noise power spectral densities (PSDs) have been derived from the analysis often seamount-free Geosat tracks in the Indian seas. The average noise PSD has been fitted by a model function. The model noise PSD has been used in conjunction with a model seamount signature to construct a matched filter for detecting seamounts in the Arabian Sea. Performance of the technique has been verified by successfully detecting the Somali ridge and the Error Seamount which are located in the Arabian Sea. Several uncharted seamounts have also been predicted.     

Localizing and extracting filament distributions from microscopy images

Detailed quantitative measurements of biological filament networks represent a crucial step in understanding architecture and structure of cells and tissues, which in turn explain important biological events such as wound healing and cancer metastases. Microscopic images of biological specimens marked for different structural proteins constitute an important source for observing and measuring meaningful parameters of biological networks. Unfortunately, current efforts at quantitative estimation of architecture and orientation of biological filament networks from microscopy images are predominantly limited to visual estimation and indirect experimental inference. Here, we describe a new method for localizing and extracting filament distributions from 2D microscopy images of different modalities. The method combines a filter‐based detection of pixels likely to contain a filament with a constrained reverse diffusion‐based approach for localizing the filaments centrelines. We show with qualitative and quantitative experiments, using both simulated and real data, that the new method can provide more accurate centreline estimates of filament in comparison to other approaches currently available. In addition, we show the algorithm is more robust with respect to variations in the initial filter‐based filament detection step often used. We demonstrate the application of the method in extracting quantitative parameters from confocal microscopy images of actin filaments and atomic force microscopy images of DNA fragments.