Comparison of wind data from QuikSCAT and buoys in the Indian Ocean

The performance of QuikSCAT‐derived wind vectors is evaluated using in‐situ data from moored buoys over the Indian Ocean. The results show that the mean differences for wind speed and wind direction are 0.37 ms^?1 and 5.8°, root mean square deviations are 1.57 ms^?1 and 44.1° and corresponding coefficients of correlation are 0.87 and 0.75, respectively. The matching between in‐situ and satellite estimates seems to be better in the North Indian Ocean than in the Equatorial Indian Ocean. The effects of sea surface temperature and air–sea temperature difference on wind residuals were also investigated. In general, QuikSCAT is found to overestimate the winds. It is speculated that low wind speed during rain‐free conditions and high wind speed, normally associated with rain, may be the reason for the less accurate estimation of the wind vector from QuikSCAT over the Indian Ocean.     

Evaluation of parameters affecting adhesive strength of high build epoxy coatings on textured and plasma treated metallic substrates

Epoxy coating systems have been used throughout the years for protecting critical industrial assets. To ensure superior coating adhesion and longevity, abrasive blasting has been traditionally employed to texture metallic surfaces. Though a large variety of abrasives are available in the industry, coal slag (aluminium silicate) and garnet (mineral abrasive) have remained popular choices until now owing to their easy availability. However, depleting reserves of coal slag owing to stricter environmental regulations and shortage of good quality garnet have fueled the need to identify substitutes. This work is focused on evaluating the effect of surface texturing on adhesive strength of epoxy coatings using two novel abrasive types – olivine (obtained from dunite rock) and calcium silicate (iron furnace slag) which are available in abundance and present an excellent alternative. The surface textures of various blast cleaned mild steel (A36) and stainless steel (316L) substrates were evaluated using a combination of techniques namely, optical profilometry (spatial parameters), replica tape method as per ASTM D 4417 (Method C) (height parameter) and scanning electron microscopy (Secondary electron imaging/energy dispersive X-ray spectroscopy analyses) for embedded particle composition analysis. Correlations were drawn to the wettability of metallic substrates textured using the selected abrasives. Adhesive strength tests on high build epoxy coatings, performed in accordance with ASTM D4541 revealed exceptional performance using various grades of both olivine and calcium silicate abrasives. The effect of air plasma treatment on adhesive strength of epoxy coatings applied on mild steel substrates were also studied.     

Development of a computer simulator for dynamic scheduling of FMS to achieve optimal performance

This paper deals with the development of a simulation software using the features of visual interactive computer graphics for analysing the dynamic scheduling of a flexible manufacturing system (FMS) to cater to the need of fluctuating markets. While carrying out this work, the main concepts of dynamic modelling, computer simulation and visual interactive graphics have been used for studying the reduction in backlogs of workorders. In addition, queue length, waiting time and the capacity utilisation of the manufacturing system are also considered. The arrival pattern of components is fitted to a suitable distribution pattern based on the workorder position. The effects of despatching rules such as SPT, LPT, EDD, SIO, SLACK, SLACK/LRO on scheduling are analysed using the simulator to imitate the real life operation of FMS. Visual interactive computer graphics enables the user to find out machine utilisation levels, queue length of the components, throughput and comparison between the application of various despatching rules. Since dynamic queue records are maintained, it is possible to establish the various components waiting in the respective work centres and their attributes like lateness, slack, remaining operations etc. This software is very useful in enabling the user to select the appropriate despatching rule for the system. The software has been developed in the C language for IBM/PC compatible systems.