Numerical investigation of natural convection for vertical flat plate with fins

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.A finite-volume-based computational study of steady laminar natural convection from a finned isothermal vertical plate with different fin arrays has been carried out to determine the heat transfer augmentation factor with different fin aspect ratio, fin spacing and inclination of fin. Heat transfer behaviors with the fins have been analyzed by examining variations of the local and average Nusselt numbers in two- dimensional flow. Four different fin arrays heights (H = 6, 12, 18, 24 mm) and four different angles of inclination ( θ = 45°, 60°,75°, 90°) are considered. In order to understand the heat transfer characteristics of this problem, a total of 96 cases for each of conductive and non- conductive fins are considered. It is found that significant heat transfer augmentation is obtained for conductive (20% higher augmentation factor when the fin aspect ratio is 6, and angle of inclination is 60° and pitch-to-length ratio is 0.2) and non-conductive fins (10% higher augmentation factor, at fin aspect ratio of 8, angle of inclination at 45° and pitch-to- length ratio at 0.5). A general correlation has been developed to predict the average Nusselt number for fin arrays as a function of different fin configurations.dc201

Achieving energy efficiency in buildings design through innovative planning and design solutions

The idea that the, earth is a finite planet in the mathematical sense is commonly accepted today. In 1972, both the Club of Rome, in its report, (Meadows et al, 1972), and the first Earth summit in Stockholm expressed this idea. This amounts to all its resources including fossil energy being limited. Renewable resources, already partially tapped, will only replace a portion of this energy. This substitution will be difficult to accomplish since the level of predation of human beings on the planet is causing serious malfunctioning of the biosphere. The building sector does not escape from today’s spotlight on the environmental impacts of human activities. Buildings are major energy consumer during both construction and ‘usage, and also generate large quantities of waste. Built up structures are consumers of 40% of the global primary energy and generator of 24% co2 emission. As such, criticality of buildings and their role in minimizing energy consumption and promoting sustainability of human habitat assumes importance. The options relating to building materials, building technologies, landscaping, heating and cooling system etc have already been explored. It is logical to apply the principles of energy costing to building prospects and look for ways to minimize energy consumption during their entire lifetime. Accordingly, the paper focuses on design strategies for making building highly energy efficient and sustainable in terms of site planning, macro and micro climatic conditions, landscaping, orientation, fenestration and shading and building materials. It discusses two case studies from India incorporating innovative design solutions to achieve energy efficiency

Noise-Aided Logic in an Electronic Analog of Synthetic Genetic Networks

We report the experimental verification of noise-enhanced logic behaviour in an electronic analog of a synthetic genetic network, composed of two repressors and two constitutive promoters. We observe good agreement between circuit measurements and numerical prediction, with the circuit allowing for robust logic operations in an optimal window of noise. Namely, the input-output characteristics of a logic gate is reproduced faithfully under moderate noise, which is a manifestation of the phenomenon known as Logical Stochastic Resonance. The two dynamical variables in the system yield complementary logic behaviour simultaneously. The system is easily morphed from AND/NAND to OR/NOR logic

A New Approach of Colour Image Encryption Based on Henon like Chaotic Map

In modern era of digital world, exchange of information in form of image often very frequently over communication channel, the secrecy of multimedia data like images becomes very important, The issue of secrecy for image resolved In many digital applications such as sensitive visual aids, broadcasting, military services, rare satellites images and confidential medical images etc. To reduce the processing overhead with the concern of Real-time data transmission application, to reduce such a huge file processing cost, we needs to enhance our encryption/decryption techniques. This paper proposed a novel image encryption technique based on Hannon like chaotic map. Chaos-based image encryption technique is one of the more promising encryption algorithms that provide very efficient and fast way of image encryption due to its ubiquitous phenomenon in deterministic nonlinear systems that exhibit extreme sensitivity to initial condition and random like behaviours. Keywords— Image RGB colour component, image encryption, Henon map, chaotic system

Population density controls on microbial pollution across the Ganga catchment

For millions of people worldwide, sewage-polluted surface waters threaten water security, food security and human health. Yet the extent of the problem and its causes are poorly understood. Given rapid widespread global urbanisation, the impact of urban versus rural populations is particularly important but unknown. Exploiting previously unpublished archival data for the Ganga (Ganges) catchment, we find a strong non-linear relationship between upstream population density and microbial pollution, and predict that these river systems would fail faecal coliform standards for irrigation waters available to 79% of the catchment’s 500 million inhabitants. Overall, this work shows that microbial pollution is conditioned by the continental-scale network structure of rivers, compounded by the location of cities whose growing populations contribute c. 100 times more microbial pollutants per capita than their rural counterparts

Numerical Investigation of Effect of Ring-Type Spacer Grid on the Thermal Hydraulics Aspects of 5 X 5 Rod Bundles

AbstractThe fuel assemblies of the Pressurized Water Reactors (PWR) are constituted of rod bundles set in a regular square configuration by spacer grids placed along its length. With the remarkable progress in the computer processing power, computational fluid dynamics (CFD) methodology can be useful for investigating the thermal–hydraulic characteristics phenomena in the nuclear fuel assembly. A methodology for the simulation and analysis of single-phase coolant flows around one or a row of spacers is presented. It is based on the multidimensional single-fluid mass, momentum and energy balance equations and use of proper turbulence models. This investigation presents results of flow simulations performed with the CD-Adapco code Star-CCM+ in a PWR 5 X 5 rod bundle part with a ring type spacer grid.A typical k-ɛ model has been used as a turbulence model and the symmetry condition is set as boundary conditions. It is confirmed that the turbulence in the sub-channel is drastically promoted by spacer and mixing devices. However, their effects quickly decayed to a fully developed level after passing about 10 times the hydraulic diameter downstream of the spacer. The static pressure of the fluid in the flow direction drops rapidly, then in a very short distance rises up, followed by a decrease near to the linear slope downstream. The simulations have also been compared with those performed by [1]

Empowering married young women and improving their sexual and reproductive health: Effects of the First-time Parents Project

The Population Council, in partnership with Child In Need Institute in Kolkata, Deepak Charitable Trust in Vadodara, and International Institute for Population Sciences, Mumbai, initiated the First-time Parents Project in India to develop and test an integrated package of health and social interventions to improve married young women’s reproductive and sexual health knowledge and practices, enhance their ability to act in their own interest, and expand their social support networks. The project was formulated on the hypothesis that the periods immediately following marriage and surrounding the first pregnancy and birth offer a unique and powerful entry point for improving the situation of married young women. Findings indicate that the intervention had a significant, positive net effect on most indicators reflecting married young women’s autonomy, social support networks, partner communication, and knowledge of sexual and reproductive health. However, the net effect of exposure to the intervention was mixed with regard to indicators related to gender role attitudes and attitudes toward domestic violence, as well as reproductive health practices. The experience of the intervention demonstrates that it is feasible to improve married young women’s reproductive health knowledge and practices, expand their sources of social support, and involve them in activities with peers in safe spaces outside the home, and through the process empower them in their marital and familial relationships. The report suggests that this model could also be integrated into existing NGO or government services, and could be tested for implementation on a larger scale

Impact of an Irreversibly Adsorbed Layer on Local Viscosity of Nanoconfined Polymer Melts

We report the origin of the effect of nanoscale confinement on the local viscosity of entangled polystyrene (PS) films at temperatures far above the glass transition temperature. By using marker x-ray photon correlation spectroscopy with gold nanoparticles embedded in the PS films prepared on solid substrates, we have determined the local viscosity as a function of the distance from the polymer-substrate interface. The results show the impact of a very thin adsorbed layer ( 7 nm in thickness) even without specific interactions of the polymer with the substrate, overcoming the effect of a surface mobile layer at the air-polymer interface and thereby resulting in a significant increase in the local viscosity as approaching the substrate interface.T. K. acknowledges the financial support from NSF Grant No. CMMI-084626. Uses of the Advanced Photon Source and the National Synchrotron Light Source were supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contracts No. DE-AC02- 06CH11357 and No. DE-AC02-98CH10886, respectively