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EN
The presence of porosity and reinforcement in a medium is an important factor affecting seismic wave propagation and plays vital role in many geophysical prospects. Also, the presence of salt and ore deposits, mountains, basins, mountain roots, etc. is responsible for the existence of corrugated boundary surfaces of constituent layers. Such facts brought motivation for the present paper which deals with the propagation of SHwave in a heterogeneous fluid-saturated poroelastic layer with corrugated boundaries lying over an initially stressed fibre-reinforced elastic halfspace. Closed form of dispersion relation has been obtained and is found in well agreement to classical Love wave equation for isotropic case. The effect of corrugation, wave number, undulation, position parameter, horizontal compressive/tensile initial stress and heterogeneity on phase velocity has been analysed through numerical computation and graphical illustration. Moreover, comparative study exploring the effect of presence and absence of reinforcement in half-space on dispersion curve is the major highlight of the current study.
2
EN
Ordered and chaotic states of a parametrically driven planar pendulum with viscous damping are numerically investigated. The damping makes the number of chaotic windows fewer but with larger width. Stroboscopic maps of the chaotic motion of the pendulum, driven either subharmonically or harmonically, show strange attractors with inversion symmetry in the phase plane.
EN
Objective. We examined the personality correlates of accident-proneness of auto-rickshaw drivers in the Indian city of Ranchi. Methods. This was a cross-sectional study in which 50 male drivers aged 18-50 years, selected randomly from a list of licensed auto-rickshaw drivers in Ranchi, were assessed with a Hindi version of Cattell's 16 Personality Factors (l6-PF) Questionnaire. Results. There was a significantly higher frequency of breaking rules, crossing speed limits, substance use and a trend towards a higher frequency of carrying extra persons (i.e., more than recommended) in accident-prone drivers. There was significant negative correlation of accident-proneness with 16-PF factors such as reasoning, rule consciousness, apprehension and emotional stability. Conclusion. Personality characteristics with lower scores of reasoning, rule consciousness, apprehension and emotional stability are common in commercial auto-rickshaw drivers with high accident-proneness.
EN
It has long been recognised that heat transfer through clothing is a main constraint to the comfort properties of clothing. The present work relates to the development of a mathematical model for the prediction of heat transmission through multilayer clothing with air in between two successive layers of fabric in a multilayered clothing assembly. A mathematical model was developed using general equations of heat transfer through porous media and was validated using experimental results. A series of multilayered fabric assemblies were created with different combinations of fabric layers and air gaps of different thicknesses. The predicted total thermal resistance of these fabric assemblies was obtained from the model and the values were compared with experimental results. The total thermal resistance of these fabric assemblies were measured using a guarded hot plate for validating the model. Fairly good correlations between the predicted and experimental values of thermal resistance were observed.
EN
The moisture transmission behaviour of a clothing assembly plays a very important role in influencing its efficiency with respect to thermophysiological body comfort. This paper is in two parts. Part I deals with the processes involved in moisture transmission and the factors at play. Part II is concerned with selecting the measurement techniques which are of great importance in determining fabric factors that influence comfort. The instruments and methods used for testing purposes should adequately simulate the exact conditions for which the fabric will be used, in order to determine the effectiveness of that fabric for a particular wearing situation and environmental condition. The testing methods used and the apparatus developed by different researchers for determining moisture transmission through textiles by different mechanisms are discussed in this paper. Moreover, this part of the paper deals with the mathematical models of liquid and vapour transport through textile materials developed by several scientists in order to understand the exact phenomena involved and to predict the factors affecting the transmission under a particular condition.
EN
Moisture transmission through textiles has a great influence on the thermo-physiological comfort of the human body which is maintained by perspiring both in vapour and liquid form. The clothing to be worn should allow this perspiration to be transferred to the atmosphere in order to maintaining the thermal balance of the body. Diffusion, absorption-desorption and convection of vapour perspiration along with wetting and wicking of liquid perspiration play a significant role in maintaining thermo-physiological comfort. The scientific understanding of the processes involved in moisture transmission through textiles and the factors affecting these processes are important to designing fabrics and clothing assemblies with efficient moisture transfer in different environment and workload conditions. This paper is in two parts.Part I focuses on the moisture transmission through textile materials and it discusses the processes involved in moisture transmission and the key influencing factors at play to maintaining comfort. It is underlined that the processes which play the major role in moisture transmission in a particular situation are dependant on the moisture content of the fabric, the type of material used, the perspiration rate and the atmospheric conditions, such as humidity, temperature and wind speed. Part II is concerned with the selection of the measurement techniques which are of great importance in determining fabric factors that influence comfort. The instruments and methods used for testing purposes should adequately simulate the exact conditions for which the fabric will be used, in order to determine the effectiveness of that fabric for a particular wearing situation and environmental condition. The testing methods used and the apparatus developed by different researchers for determining moisture transmission through textiles by different mechanisms are discussed in this paper. Moreover, this part of the paper deals with the mathematical models of liquid and vapour transport through textile materials developed by several scientists in order to understand the exact phenomena involved and to predict the factors affecting the transmission under a particular condition. When designing the comfort of a clothing product for a particular application, the requirements may result from needs concerning the application, the individual wearer and the environmental conditions.
7
Content available remote A study on frictional characteristics of woven fabrics
EN
We have examined the fabric-to-metal surface and fabric-to-fabric frictional characteristics (in both warp and weft directions) of a series of fabrics containing 100% polyester, 100% viscose, and P/C & P/V blends with different blend proportions. It has been observed that the normal load and the frictional force follow a logarithmic relationship for all the fabrics. The nature of fabric friction is characterised by different parameters such as the F/N ratio, and the values of n, k and k/n. Fabric-to-metal friction is found to be less sensitive to fabric morphology and rubbing direction, whereas fabric-to-fabric friction is highly sensitive to these factors. Fabric friction has been affected by many factors such as the type of fibre, type of blend, blend proportion, yarn structure, fabric structure, crimp and crimp height, compressibility, etc. In P/C and P/V blended fabrics, the frictional force increases as the cellulose fibre component increases.
EN
The end breakage in rotor spinning not only reduces the running efficiency of the process, but also deteriorates the quality of the yarn in terms of presence of piecing slubs. A new system has been proposed to classify the end breaks in rotor spinning broadly into seven groups, depending on the configuration of broken ends. By examining the broken end, the probable causes of breakage can be predicted and necessary preventive action can be taken. The rate of end breakage and the proportion of different types of breakages vary with different process variables like yarn count, rotor speed, opening roller speed and residual trash content in draw frame sliver.
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