Vibration of plates immersed in hot fluids

The vibration of structures immersed in water has been studied by Lamb and others. The influence of thermal stresses on the vibration characteristics of plates has been investigated and reported by several researchers. The work reported here deals with the determination of natural frequencies of plates immersed in water and subjected to six types of temperature distributions. The analysis is based on finite element method. A comment on thermal buckling of plates immersed in water is also reported.     

Finite element analysis of contact–impact between a shell of revolution and a rigid wall

In this paper an attempt is made to use a shell theory that includes transverse normal stresses to study the contact–impact behaviour involving thick shells. The problem is solved using the finite element method. The contact criterion is imposed by means of displacement and force constraints. The Lagrangian multipliers technique is used to impose these constraints. The case of a spherical shell impacting a rigid wall with a constant velocity is considered for the analysis. It is shown that the method produces accurate results with less amount of computation than the usual three-dimensional analyses. The effects of the thickness of shell, velocity of impact and modulus of the material are studied.     

Chip-on board technology for low temperature environment. Part II: Thermomechanical stresses in encapsulated ball-wedge bond wires

Wire-bonded chip-on-board (CoB) multi chip modules consist of die and bond wires that are encapsulated to protect them from mechanical and chemical damage. This paper describes a rapid-assessment model for the prediction of thermomechanical strains developed in the encapsulated ball-wedge bond wires due to thermal expansions experienced during curing or subsequent environmental changes. The wire profile is modeled using a piece-wise continuous polynomial function (cubic spline) with appropriate boundary conditions at the two bond sites. Plastic deformation is ignored in the current analysis as a first-order approximation. Then a 2D Raleigh-Ritz (RR) model is developed to estimate the thermomechanical stresses in the bond wire due to temperature cycling in the presence of an encapsulant. The purpose of the model is to provide a rapid ranking of the thermomechanical robustness of different wire-bond design options. Results are validated by detailed 2D finite element analysis (FEA) and are compared to fatigue failure data available from thermal cycling tests.     

Influence of cerium oxide additive and aloe vera biodiesel on a CI engine

Diesel is the main source of world transportation due to higher combustion efficiency, compliance, consistency and cost-economy. It is also a major contributor to the world prosperity since it is used extensively. Diesel engine’s emissions are the serious hazard to the world environment and it is measured to be the major causes of air pollution. The demand in biofuels for years created a scope for aloe vera into biodiesels. Aloe vera, having higher calorific value vnthan other plant sources used as biodiesels, enhanced us in making another alternative biodiesel, which has lesser emissions and better performance. In this research work, four biodiesel blends from aloe vera oil with cerium oxide additive are explored for their performance and emission characteristics. The results proved B30 (30% biodiesel, 68% diesel and 1% cerium oxide) gives good performance when compared to other blends.     

High temperature tensile properties of 316LN stainless steel investigated using automated ball indentation technique

Type 316LN stainless steel (SS) is the principal structural material for the components of sodium cooled fast reactors operating under elevated temperature conditions. In order to assess the degradation in strength of service exposed components using a small specimen testing technique such as automated ball indentation (ABI), it is necessary to carry out prior detailed ABI studies on the virgin material. In this investigation, the tensile behaviour of as-received 316LN SS were investigated at several temperatures in the range 298–973 K using ABI technique. The load-depth of indentation data measured from ABI tests was analyzed using semi-empirical relationships to obtain the tensile properties. The yield stress and the flow curves were determined by correlating ABI results with corresponding uniaxial tensile test results. Trend curve for tensile strength with temperature, as estimated from ABI tests, exhibited a plateau region in the temperature around 823 K, similar to uniaxial tensile tests. The variations of strength coefficient, strain hardening exponent, yield ratio, hardness and uniform ductility with temperature were evaluated from ABI tests. The ABI technique was found to estimate the influence of temperature on tensile properties sensitively.     

Creep behavior of nuclear grade 316LN austenitic stainless steel at 873 K and 923 K

Mechanics of Time-Dependent Materials - Creep deformation and rupture behavior of nitrogen-alloyed (0.14 wt.%) nuclear grade 316LN austenitic stainless steel were investigated for the varying...     

RETRACTED ARTICLE: Tolerance rough set firefly-based quick reduct

In medical information system, there are a lot of features and the relationship among elements is solid. In this way, feature selection of medical datasets gets awesome worry as of late. In this article, tolerance rough set firefly-based quick reduct, is developed and connected to issue of differential finding of diseases. The hybrid intelligent framework intends to exploit the advantages of the fundamental models and, in the meantime, direct their restrictions. Feature selection is procedure for distinguishing ideal feature subset of the original features. A definitive point of feature selection is to build the precision, computational proficiency and adaptability of expectation strategy in machine learning, design acknowledgment and information mining applications. Along these lines, the learning framework gets a brief structure without lessening the prescient precision by utilizing just the chose remarkable features. In this research, a hybridization of two procedures, tolerance rough set and as of late created meta-heuristic enhancement calculation, the firefly algorithm is utilized to choose the conspicuous features of medicinal information to have the capacity to characterize and analyze real sicknesses. The exploratory results exhibited that the proficiency of the proposed system outflanks the current supervised feature selection techniques.

     

Lowering the outdoor temperature in high-rise high-density residential developments of coastal Hong Kong: The vegetation influence

This paper investigates the impact of on-site variables on the influence of vegetation in lowering outdoor temperature. The study uses six critical on-site variables such as surface albedo, sky view factor, altitude, shrub cover, tree cover and average height to floor area ratio to carry out analysis in five data sets. The climatic parameters and physical characteristics were measured and surveyed, respectively in 216 stations in high-rise high-density residential developments of coastal Hong Kong. The data set is mainly categorised into peak summer clear sky days (PSCS-days), peak summer partially cloudy days (PSPC-days) and late summer days to address the issues related to cloudy sky conditions in Hong Kong. The trend analysis shows that at a lower sky view factor, ranging from 0.1 to 0.25, shrub cover as low as 10–15% in a 1000 m² open area is more effective in reducing outdoor temperature than the same level of tree cover in a location with a higher sky view factor (0.4 or above). The regression models used in this study were able to explain the influence of on-site variables on vegetation in lowering the outdoor temperature within the respective urban settings. In high-rise high-density environments, on-site variables such as sky view factor and altitude have a substantial impact on the influence of vegetation in lowering outdoor temperature. However, off-site variables such as high urban density and anthropogenic heat could negate the behaviour of sky view factor and altitude. The study suggests that increasing the tree cover from 25% to 40% in the pocket parks in coastal area residential developments of Hong Kong could reduce daytime urban heat island intensity (UHI) by further 0.5 °C.