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The present work developed a national web-based corrosion cost inventory system for the Kingdom of Saudi Arabia which can be used by any nation with little bit of customization. The paper aims to discuss these issues.

The proposed system is designed to be divided into five major sectors namely, utilities, transportation, infrastructure, government, and production and manufacturing. Each of these major sectors is having further sub-sectors and then blown down to the industry and specific identity. The web-based application is developed using Dotnet on SQL server. The corrosion cost estimation procedures and corrosion rates in different sectors and sub-sectors have been adapted from the literature.

The proposed developed system will enable end-users to provide corrosion and cost-related data through web-based online system. The input information from end-users will be authenticated by a corrosion auditor before finally entering into the database tables. The system is also capable of generating reports related to corrosion cost which the nation is paying with further details of corrosion costs borne by each sector and sub-sector. These reports will be helpful in making decision to identify the sector and sub-sectors which are more prone to corrosion and consuming more money to combat corrosion. Finally, the sectors and sub-sectors that are identified through the proposed system could be put under thrust research areas to combat corrosion problem and hence reduce the corrosion cost burden in future.

To the best of authors' knowledge, this is the first attempt on providing a web-based corrosion cost inventory system on national basis which could be adapted by any nation with some customization. It is flexible and can be expanded as the need may arise.

The annual and seasonal variation of meteorological parameters has been studied for twenty stations in Saudi Arabia. The contour maps showed temperature and rainfall increasing and wind speed decreasing trends with decreasing latitudes. The mean temperature varied between a minimum of 8.4°C and a maximum of 34.61°C while overall mean was 23.95°C. The Mean, minimum and maximum values of pressure were 932.12, 923.3 and 944.6mb, respectively. The corresponding relative humidity values were 42.7, 78.5 and 21.5%, respectively. The empirical models developed for the prediction of monthly mean values of individual parameters were able to estimate the values with acceptable accuracy

The present study utilizes daily mean time series of meteorological parameters (air temperature, relative humidity, barometric pressure and wind speed) and daily totals of rainfall data to understand the changes in these parameters during 17 years period i.e. 1990 to 2006. The analysis of the above data is made using continuous and discrete wavelet transforms because it provides a time‐frequency representation of an analyzed signal in the time domain. Moreover, in the recent years, wavelet methods have become useful and powerful tools for analysis of the variations, periodicities, trends in time series in general and meteorological parameters in particular. In present study, both continues and discrete wavelet transforms were used and found to be capable of showing the increasing or decreasing trends of the meterorological parameters with. The seasonal variability was also very well represented by the wavelet analysis used in this study. High levels of compressions were obtained retaining the originality of the signals.

This paper aims to present the results of an experimental investigation carried out to control the base pressure in a suddenly expanded axi‐symmetric passage.

Four micro‐jets of 1 mm orifice diameter located at 90° interval along a pitch circle diameter of 1.3 times the nozzle exit diameter in the base region was employed as active controls. The test Mach numbers were 1.25, 1.3, 1.48, 1.6, 1.8, 2.0, 2.5 and 3.0. The jets were expanded suddenly into an axi‐symmetric tube with cross‐sectional area 4.84 times that of nozzle exit area. The length‐to‐diameter ratio of the sudden expansion tube was varied from 10 to 1. Nozzles generating the above jet Mach numbers were operated with nozzle pressure ratio in the range 3‐11. As high as 40 per cent increase in base pressure was achieved. In addition to base pressure, the wall pressure in the duct was also measured.

It is found that the wall pressure is not adversely influenced by the micro jets.

The paper provides information on internal supersonic flow.