A test rig for testing radial diffusers

A simple test rig for investigating the performance of vaneless diffusers with diverging walls for centrifugal compressors has been designed, fabricated and satisfactorily tested. The test rig was designed to give values of area ratio from 1·5 to 6 for an included angle of 10°. A uniform flow at the entry of the diffuser had been achieved by the use of a centre body and suction on both the walls. The swirl was zero in all the tests.A maximum Reynolds' number of 2·8 × 10⁵ can be obtained during the tests. Experimental values of the coefficients for losses, the pressure recovery and efficiency were obtained from the measurements of static and stagnation pressures.     

Misalignment effects on steady‐state and dynamic behaviour of compliant journal bearings lubricated with couple stress fluids

This work concerns the steady‐state and dynamic analysis of misaligned compliant journal bearings considering the effects of couple stresses arising from the lubricant blended with polymer additives. Based on the Stokes micro‐continuum theory, a modified form of the Reynolds equation is derived. The displacement field at the fluid film–bearing liner interface due to pressure forces is determined using the elastic thin liner model. The effects of the misalignment and the couple stress parameters on static and dynamic performances such as pressure distribution, load‐carrying capacity, power loss, side leakage flow, misalignment moment, critical mass and whirl frequency are presented and discussed. Copyright © 2008 John Wiley & Sons, Ltd.     

Reduction of Brochothrix thermosphacta and Salmonella Serotype Typhimurium on Vacuum-Packaged Fresh Beef Treated with Nisin and Nisin Combined with EDTA

ABSTRACT: The effect of nisin and nisin/EDTA followed by vacuum packaging on the reduction of Brochothrix thermosphacta and Salmonella typhimurium counts on beef was investigated. Beef cubes, inoculated with either bacteria, were dipped in nisin, or nisin combined with EDTA solutions, vacuum packaged, and stored at 4 °C for up to 25 d. Growth of B. thermosphacta was completely inhibited by nisin and nisin/EDTA by up to 6.76 log₁₀ CFU/ml. However, neither treatment showed significant effects against S. Typhimurium. Thus, nisin or nisin/EDTA treatment, followed by vacuum packaging under refrigerated conditions could increase the shelf life of fresh beef by inhibiting the growth of B. thermosphacta , an important spoilage organism in beef.     

Design and installation of solar photovoltaic powered water pumping system at Usmanu Danfodiyo University, Sokoto

The paper presents the outcome of the powering of a conventional a.c. type water pump by photovoltaic (pv) solar modules which were 28 in number connected 7 in series giving a total of 4 parallel strings. An assesment of the system, which provides water to the University Mechanical Workshop and a nearby village, shows that the system has been operating continously since October 1993 and on average 20 m³ of water is pumped daily at average solar radiation level of 5kWh/m²/day.