Fluid Mechanics; Research on fluid mechanics discussed by scientists at Multimedia University

According to recent research from Malaysia, Both hydro-dynamically and thermally fully developed laminar heat transfer of non-Newtonian fluids between fixed parallel plates has been analyzed taking into account the effect of viscous dissipation of the flowing fluid

Field synergy principle analysis on convective heat transfer in porous medium with uniform heat generation for thermally developing flow

The field synergy analysis for forced convective heat transfer in porous medium between two parallel plates is augmented from the earlier study on developed flow to the present thermally developing flow. The temperature variations along the axial and transverse directions for both adiabatic and isoflux boundary conditions are studied. Green's function solution integrated with the extended weighted residuals method is adopted in this study to first obtain the temperature profile. The variation of intersection angle in the context of field synergy analysis is discussed in relations to the Nusselt number, boundary conditions and the shape factor. (C) 2012 Elsevier Ltd. All rights reserved

Use of lagrange time delay estimation interpolation in the magnification of electron microscope images

Image interpolation has been used widely to perform magnification by predicting missing details from a sampled image. As most of the signal information is distributed around edges and areas of sharp changes, there is a need of designing an interpolation technique that is able to predict these changes precisely. However, many conventional polynomial-based interpolation methods tend to smooth or blur out image details around the edges. In this paper, a novel method called Lagrange time delay estimation interpolation (LATDEI) model is proposed, to confront the problem. Simulation results shows that the consistency of LATDEI performance, in obtaining better images, implies that it is a promising estimator for image interpolation of various images. Compared to two traditional methods, the proposed LATDEI method improves the subjective quality of the interpolated edges while providing a better resolution

Application of optical character recognition in thermal image processing

This paper presents the results of a study on the reliability of the thermal imager compared to other devices that are used in preventive maintenance. Several case studies are used to facilitate the comparisons. When any device is found to perform unsatisfactorily where there is a suspected fault, its short-fall is determined so that the other devices may compensate, if possible. This study discovered that the thermal imager is not suitable or efficient enough for systems that happen to have little contrast in temperature between its parts or small but important parts that have their heat signatures obscured by those from other parts. The thermal imager is also found to be useful for preliminary examinations of certain systems, after which other more economical devices are suitable substitutes for further examinations. The findings of this research will be useful to the design and planning of preventive maintenance routines for industrial benefits. (C) 2011 Elsevier B.V. All rights reserved

Viscous dissipation effect on CuO-Water nanofluid-cooled microchannel heat sinks

While a microchannel heat sink is known to regulate the temperatures of microelectronics devices, viscous dissipation that originates from work done by viscous forces, might have an impact on the heat convection coefficient from a heated boundary. In this study, the exact solution of the temperature field is established for a fully developed forced convection in a parallel plate channel saturated with a porous medium, subjected to uniform heating at one boundary. Applying the new temperature field in a microchannel heat sink, modelled as a porous medium, this study gauges the effect of viscous dissipation on the electronics cooling device; utilizing a 4% volume fraction CuO-Water nanofluid as a coolant. Assuming a homogeneous model whereby the concentration of the nanofluid is taken as uniform spatially, the two-dimensional temperature field, computed based on the effective thermophysical properties of the nanofluid, reveals that viscous dissipation affects the heat convection at the heated boundary adversely, lowering the heat transfer coefficient by 15.3%, for Reynolds number, Re=1500 and elevates the temperature gradient in the vicinity of the insulated boundary

Field synergy principle analysis on fully developed forced convection in porous medium with uniform heat generation

In the presence of uniform heat source, the energy equation for forced convective heat transfer in porous medium between two parallel plates is solved for fully developed flow. Field synergy analysis is performed with emphasis on the intersection angle between the velocity vector and temperature gradient vector with the inclusion of heat generation. Maximum local intersection angle corresponds to location with the highest resistance to heat convection. Relationship between Nusselt number and field synergy for forced convection in the presence of heat generation is studied. It is necessary to define a modified intersection angle in order to compare the wall heat transfer coefficient for convective heat transfer processes with uniform heat source. (C) 2011 Elsevier Ltd. All rights reserved

Performance of new signal-to-noise ratio estimation for SEM images based on single image noise cross-correlation

A new technique for estimation of signal-to-noise ratio in scanning electron microscope images is reported. The method is based on the image noise cross-correlation estimation model recently developed. We derive the basic performance limits on a single image signal-to-noise ratio estimation using the CramerRao inequality. The results are compared with those from existing estimation methods including the nearest neighbourhood (the simple method), the first order linear interpolator, and the autoregressive based estimator. The comparisons were made using several tests involving different images within the performance bounds. From the results obtained, the efficiency and accuracy of image noise cross-correlation estimation technique is considerably better than the other three methods

Life cycle assessment study of solar PV systems: An example of a 2.7kWp distributed solar PV system in Singapore

In life cycle assessment (LCA) of solar PV systems, energy pay back time (EPBT) is the commonly used indicator to justify its primary energy use. However, EPBT is a function of competing energy sources with which electricity from solar PV is compared, and amount of electricity generated from the solar PV system which varies with local irradiation and ambient conditions. Therefore, it is more appropriate to use site-specific EPBT for major decision-making in power generation planning. LCA and life cycle cost analysis are performed for a distributed 2.7 kW(p) grid-connected monocrystalline solar PV system operating in Singapore. This paper presents various EPBT analyses of the solar PV system with reference to a fuel oil-fired steam turbine and their greenhouse gas (GHG) emissions and costs are also compared. The study reveals that GHG emission from electricity generation from the solar PV system is less than one-fourth that from an oil-fired steam turbine plant and one-half that from a gas-fired combined cycle plant. However, the cost of electricity is about five to seven times higher than that from the oil or gas fired power plant. The environmental uncertainties of the solar PV system are also critically reviewed and presented. (C) 2005 Elsevier Ltd. All rights reserved