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61.
62.
This paper deals with the prediction of heat transfer coefficient of steel bars subjected to Tempcore process. A nonlinear mathematical model, in terms of process variables, is developed using response surface methodology. Three significant control parameters are considered. Central composite design of experiments is structured and conducted using finite element method to formulate the predictive nonlinear model. Statistical analysis and experimental results suggest that the proposed model could be used for predicting heat transfer coefficient with adequate accuracy. The knowledge of heat transfer coefficient makes it possible to predict temperature evolution in the steel rods. As the temperature distribution affects the mechanical properties of steel rods, the proposed methodology can be effectively employed in controlling the quality of products.  相似文献   
63.
A salt base exothermic reaction process has been employed to produce aluminum alloy 2014 matrix-TiB2 composites using an exothermic reaction process at 850 °C using K2TiF6 and KBF4 salts. The period of exothermic reaction was varied from a minimum of 15 min to a maximum of 45 min to investigate the relationship between the degree of reaction and the growth behavior of TiB2 formed. These have been compared with commercially available aluminum alloy 2014 material. Structural and wear properties have been measured. These show that TiB2 is extremely effective in enhancing wear properties in addition to significantly reducing the coefficient of friction. The microstructure and phase composition of the materials obtained were studied using X-ray diffraction and scanning electron microscopy (SEM). Very fine ceramic particles were obtained in the aluminum alloy matrix.  相似文献   
64.
Copper pitting is a complicated corrosion process for which exact causes and solutions are often uncertain. This paper presents the findings of a comprehensive investigation of a cold water copper pitting corrosion problem in a drinking water distribution system, including a refined process for preparing exhumed copper pipes for solids analysis. The investigation produced detailed structural, morphological and elemental details of copper pitting that strongly corroborated previous observations and theoretical models, and revealed new findings. For example, cross-sections revealed three components: the cap, characterized by two basic copper sulfate minerals; the cuprite membrane; and the pit containing cuprite crystals, and chloride.  相似文献   
65.
Components of cereals, legumes, pulses, proteins, sea food, milk, carbohydrates and lipids are being evaluated for their influence on human health, as biofunctional compounds. However, references dealing with fruits and vegetables exceed any other food group and accordingly their focus. Fruits and vegetables abound in a spectacular range of such health influencing compounds and thus, study of their bioactivity, in lieu of their consumption in fresh or processed form. Anti-cancerous phenolics from Phyllanthus, radioprotective Litchi phenolics/flavonoids, hypoglycemic Sygium, quercitin and hydroxyl cinnamates of Sweet cherries, xanthones of Mangosteen, ellagitannins of Pomegranate, ursolic acid of Sea buckthorn, muscle relaxative watermelon, anti-cholesterolemic soluble fibre and sterols, cardioprotective saponins, ACE-inhibitory potato hydrolysates, anti-pancreatic cancerous ascorbic acid, carotenoids including pro-vitamin A are few examples unraveled. Thus, the imminent scope to obviate their structural chemistry, influence on storage and processing conditions, factors favoring their bio-accessibility/bio-availability in the food formulations, influencing human health. It is the meticulous combination of these compounds in daily consumption that determines their usefulness to human body. What is of paramount importance is the actual health benefits accrued from consumption of such functional- compound based fresh/processed fruits,vegetables or other foods.  相似文献   
66.
In the present work, autonomous mobile robot (AMR) system is intended with basic behaviour, one is obstacle avoidance and the other is target seeking in various environments. The AMR is navigated using fuzzy logic, neural network and adaptive neuro-fuzzy inference system (ANFIS) controller with safe boundary algorithm. In this method of target seeking behaviour, the obstacle avoidance at every instant improves the performance of robot in navigation approach. The inputs to the controller are the signals from various sensors fixed at front face, left and right face of the AMR. The output signal from controller regulates the angular velocity of both front power wheels of the AMR. The shortest path is identified using fuzzy, neural network and ANFIS techniques with integrated safe boundary algorithm and the predicted results are validated with experimentation. The experimental result has proven that ANFIS with safe boundary algorithm yields better performance in navigation, in particular with curved/irregular obstacles.  相似文献   
67.
Suspensions of solid particles in viscous fluid flowing through bifurcating channels are encountered in various industrial processes and biological applications. This work reports the detailed numerical simulations of shear‐induced particle migration in oblique bifurcating channels. The effect of particle concentration, bifurcation angle, and flow rate on the partitioning of bulk flow and particles in the downstream branches is studied. It was observed that the particle distribution in the downstream branches does not follow the flow distribution due to shear‐induced particle migration. The velocity and concentration profile for suspension flow were observed to be symmetric in the inlet branch but asymmetric in the daughter branches. The degree of asymmetry and bluntness of velocity profile was observed to depend on the bulk particle concentration and bifurcation angle. The reported results could be useful in the design of flow devices handling suspension transport in bifurcating channels. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2692–2704, 2014  相似文献   
68.
Molecular transport of n‐alkanes was investigated by calculating sorption, diffusion, and permeation of liquids through the diol chain‐extended polyurethane (PU) membranes in the temperature interval 25–60°C. Sorption experiments were performed gravimetrically. Diffusion coefficients were calculated from Fick's equation. These results showed a dependency on the nature and size of interacting n‐alkane molecules as well as morphology of the chain‐extended PUs. Transport kinetics followed an anomalous trend. Using the temperature‐dependent transport parameters, activation energies were calculated for diffusion and permeation processes using an Arrhenius equation. The van't Hoff relationship was used to obtain enthalpy and entropy of sorption. Concentration profiles of liquids through PU membranes were computed using Fick's equation, solved under appropriate initial and boundary conditions. A correlation was attempted between transport properties of liquids and physicomechanical properties of PU membranes. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 874–882, 2005  相似文献   
69.
Multiple Linear Correlation Analysis of Daily Reference Evapotranspiration   总被引:3,自引:3,他引:0  
An accurate estimation of reference evapotranspiration (ET0) is of paramount importance for many studies such as hydrologic water balance, irrigation system design and management, crop yield simulation, and water resources planning and management. Simple regression techniques, may sometimes, provide adequate estimation of ET0. Implementation of regression methods considering all the predictor variables may, however, lead to overfit and consequent reduction in the predictive capability. The regression models for ET0 have been developed in the present study for Tirupati, Nellore, Rajahmundry, Anakapalli and Rajendranagar regions of Andhra Pradesh, India by following step-wise procedure, eliminating superfluous predictor variables based on statistical criteria. The sunshine hours, wind velocity, temperature and relative humidity influenced ET0 in the study area. The linear regression models developed in terms of predictor variables may conveniently be applied in the regions selected for the present study and, in the regions with similar climatic conditions for satisfactory ET0 estimation.  相似文献   
70.
The allocation of design and manufacturing tolerances directly influences the manufacturing cost and functionality of a product. Traditionally, it is carried out in two phases; CAD and CAPP, in a sequential manner. This approach has the drawbacks of more lead-time and sub-optimality. The present work reports on a procedure to simultaneously allocate both design and manufacturing tolerances based on minimum total manufacturing cost. The optimization model for tolerance design is a non-linear multivariable problem. Since such a problem may have a noisy surface, there is a need to apply an efficient global optimization technique. In the present work, scatter search, one of the recently emerged optimization techniques in the area of metaheuristics, is applied successfully to determine the optimal tolerances at the minimum manufacturing cost. An example is taken from the literature to explain the proposed methodology. The results exhibit the effectiveness of the proposed algorithm over other methods.  相似文献   
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