RUPTURE OF THIN MICROPOLAR LIQUID FILM ON A CYLINDER

The dynamic rupture process of a thin liquid film on a cylinder has been analyzed by investigating the stability to finite amplitude disturbances. The dynamics of the liquid film is formulated using the balance equations including a body force term due to van der Waals attractions. The governing equation for the film thickness was solved by finite difference method as part of an initial value problem for spatial periodic boundary conditions. A decrease in the cylinder radius will induce a stronger lateral capillary force and thus will accelerate the rupture process. The rupture time increases with the material parameter, Δ.     

THERMAL DISPERSION EFFECTS ON NON-DARCY NATURAL CONVECTION WITH INTERNAL HEAT GENERATION

A similarity solution is presented to study the influence of lateral mass flux and thermal dispersion on non-Darcy natural convection over a vertical fiat plate with an exponential type of internal heat generation in a fluid saturated porous medium. The coefficient of thermal diffusivity has been assumed to be the sum of molecular diffusivity and the dispersion thermal diffusivity due to mechanical dispersion. The suction/injection velocity distribution has been assumed to have power function form Ax^λ , where x is the distance from the leading edge and the wall temperature distribution is assumed to be uniform.     

Well-being analysis of GSU transformer insulation incorporating the impact on power generation using fuzzy logic

With the prevailing power scenario, every watt-second of electrical energy has its own merit in satisfying the consumer demand. At the state of such a stringent energy demanding era, failure of a power generation equipment compounds the energy constraints which will not only result in a huge loss of generation but also have an impact on capital revenue. The unexpected failure of generator step-up (GSU) transformer is especially a major disturbance in the power system operation and leads to unscheduled outages with power delivery problems. The time lag in bringing back the equipment in service after rectification or replacement may increase the criticality as the process involves mobilization of spares and maintenance professionals. Hot atmosphere existing in the vicinity of thermal power stations running round-the-clock with more than 100% plant load factor (PLF) increases the thermal stress of the electrical insulation which leads to premature failure of windings, bushings, core laminations, etc. The healthy state of the GSU transformer has to be ensured to minimize the loss of power generation. As the predication related to failure of a GSU transformer is associated with some uncertainties, a fuzzy approach is employed in this paper along with actual field data and case studies for the well-being analysis of GSU transformer.     

Thermal Performance of ‘Still-on-Roof’ System with Water Flowing through the Roof

In the present communication, authors propose and analyze a system which consists of a solar still kept over the roof of a room, and a water-flowing arrangement in the roof. The performance of the system is studied under two modes of heat extraction, viz., constant flow rate, and constant collection temperature, An analytical model has been developed which provides explicit expressions for various performance parameters of the system. The model is useful in evaluating the system performance under the variation of different parameters. In order to appreciate the proposed configuration, numerical calculations are carried out corresponding to the typical climate of Delhi, India. The calculations show that the system is effective in reducing the heat flux entering the room and provides warm water in addition to the distilled water.     

Changes in Fatty Acids and Sensory Quality of Fresh Water Prawn (Macrobrachium rosenbergii) Stored Under Frozen Conditions

The effects of frozen storage and packaging methods on the oxidation of fatty acids and rancidity development in fresh-water prawn Macrobrachium rosenbergii were studied. The lipids of these fresh prawns contained 23% saturated, 46% monounsaturated, and 31% polyunsaturated fatty acids. The fatty acids, especially the unsaturated ones decreased during frozen storage for 6 months at -18°C, regardless of the packaging procedure employed. No objectionable rancid flavor was detected in these prawns during the 6-month frozen storage study.     

Toxin Development by Clostridium botulinum in Modified Atmosphere-Packaged Fresh Tilapia Fillets During Storage

Potential for toxin development by Clostridium botulinum type E was investigated in retail-type packages of fresh tilapia fillets packaged in high barrier film under selected atmospheres [100% air, a modified atmosphere (MA) containing 75%CO₂:25%N₂, and vacuum] and stored under refrigeration (4°C) and abuse temperatures (8 and 16°C). Toxin development coincided with sensory spoilage at 16°C storage for fillets packaged in either MA, or vacuum. At 8°C, toxin development in fillets packaged in either of the atmospheres occurred 7-23 days after sensory spoilage. At 4°C, none of MA-packaged fillets became toxic until 10 days after onset of sensory spoilage. Toxin development did not precede sensory spoilage in any treatments or temperatures studied.     

Structure-performance-fouling studies of polysulfone microfiltration hollow fibre membranes

Hollow fibre microfiltration membranes were prepared by solution spinning process using polymer dope containing different amounts of polysulfone (PS), polyvinylpyrollidone (PVP) and ${\bf \textit{N}}$ , ${\bf \textit{N}}$ -dimethylformamide (DMF). Spinning dope having PS: PVP: DMF (w/w) of 15: 5: 80, 15: 7: 78 and 17: 8: 75 were used for spinning to obtain hollow fibres having different dimensions (outer and inner diameters) and pore characteristics. Relatively high water permeability was observed for hollow fibre membrane spun from 15?wt.?% solution than 17?wt.?% PS solution having the same PVP/PS ratio of 0·47. Decrease of the PVP/PS ratio to 0·33 in the dope solution of 15?wt.?% PS solution produced hollow fibre membrane with lower flux. By changing the spinning parameters, fibre with different dimensions were obtained without a significant change in microstructural morphology. The flux decline due to fouling for the permeation of PEO/BSA solution was maximum for the hollow fibre membrane obtained from 15?wt.?% PS solution while a steady flux with slight fouling was observed for the hollow fibre membrane obtained from 17?wt.?% PS solution, when the PVP/PS ratio was 0·47.     

INACTIVATION OF CLOSTRIDIUM BOTULINUM TYPE E SPORES BY HIGH PRESSURE PROCESSING

The effect of high pressure treatments at various temperature combinations on the inactivation of Clostridium botulinum type E spores of strains, Alaska and Beluga in phosphate buffer (0.067 M, pH 7.0) was investigated. No reduction of spores was observed at any pressurization (Maximum = 827 MPa) for temperatures below 35C. At pressurization of 827 MPa for 5 min, log unit reduction of spores increased as temperatures increased from 35 to 55C. An increase in the processing time from 5 to 10 min at a combination of high pressure (827 MPa) and low temperature (40C) resulted in a 5-log reduction of Alaska spores. About 5-log reductions for strains Alaska and Beluga occurred at 50 and 55C, respectively, after processing at pressures of 827 MPa for 5 min.