Comparative study on seismic analysis of buildings for different code of practices commonly used in Sri Lanka

Earthquake threat has been identified by many countries and analysis and design against seismic effects have therefore become almost a basic part of their structural design process. Sri Lanka has also identified the importance of designing buildings against seismic actions, specially due to recent incidents, which took place in and around the Island. However, Sri Lanka does not have its own code of practice for designing against seismic actions. Also there are not many established guidelines available in the country for this purpose. As a result, when it is required to analyze and design buildings against seismic actions, the engineers and scientists in the country face difficulties, basically with which codes and guidelines to follow. It is obvious that all of those codes are not equally suitable for conditions in Sri Lanka and also will not give out similar results. The aim of this research is to check the performance level that a building can achieve when analyzed according to different codes of practice, which are commonly used in Sri Lanka in seismic analysis. In this context, three codes of practice were considered, taking into account their applicability over the others in Sri Lankan context, namely the Australian code (AS1170.4-2007), the Indian code (IS 1893 (Part 1):2002) and the Euro code (BS EN-1998-1:2004). The recommendations provided in the research, conducted by the University of Moratuwa, Sri Lanka, aimed at providing guidance on suitable analysis procedures for buildings in Sri Lanka, based on the euro code were also inco-operated in the analysis. First, the seismic analysis procedures outlined in those codes with respect to both static and dynamic analysis were discussed in detail. Then, the analysis procedures introduced in the respective codes of practice were compared and contrasted, considering how they handle the major effects, characteristics of the structures and geotechnical considerations etc. In order to demonstrate the analysis procedures and to make a comparison on results, three high-rise buildings, having floors between 10 to 20 were selected and analyzed according to the guidelines provided in the three selected codes of practice respectively. In this case, all the structures were analyzed for three different soil conditions, which could be found in Sri Lanka. The computer software "ETABS" has been used for finite element modeling of all the structures. Response Spectrum Analysis (RSA) was used in all the dynamic analysis purposes. Equivalent static analysis was also carried out as per requirements, established in particular codes of practice. According to the results obtained in the analysis, it has been found that, irrespective of the code of practice, which has been used in the analysis, the structures have achieved Immediate Occupancy Level (IOL)in all twenty seven cases, according to FEMA356 standards. It was also found that the Indian code has given the highest drift values in many occasions while the Euro code also has given very close or sometimes similar drift values. In contrast, the Australian code has generally resulted lowest drift values. Further, it has also been identified that the Euro code has given the highest design base shear forces in all eighteen occasions. On the other hand, the Indian code has given lowest design base shear force in many occasions. The Australian code has also shown the lowest design base shear forces in few occasions

A Study of indigenous dye producing plants and their derivatives in textile dyeing

With the discovery of synthetic dyes all colour industries, not only textile industry had turned to the more economical, reproducible, high colour fast and easy to use synthetic dyes and abandoned the natural dyeing tradition which had prevailed as the only colouring technology till then. But recently a revival in the natural dye in technology has occurred as solutions to the environmental pollution arising out of the wet processing of textiles as well as to the growing trend of dye toxicity and all ergie s to the textile consumers. Natural dyes provide not only a good alternative to the environmental pollution arising from synthetic dyes but also provide low toxicity and allergic reactions while giving unique and fascinating colours which are not achieve able from synthetic dyes. A thorough review to the historic background of the origin and progression of natural dyeing techniques in the world with specific concern to Sri Lanka was carried out .During this review a search was also made into the reasons for the erosion of this valuable tradition of natural dyeing. Through a survey of the natural dye producing plants world over, a list of indigenous dye producing plants in Sri Lanka was preparedand investigated the possibility of using one of these plant sources to develop a new natural dye based on its extraction. In selection of this plant source the major concern was given to the fact that it should be abundant as a waste material in Sri Lanka. Black tea, which is highly available as a waste (dust) from tea factories and domestic sources (brewed tea) were used to extract polyphenols, which are an abundant form of natural compounds in tea. These were used as the coupling component to produce a zocompounds by coupling with different diazonium salts. Both polyphenols and azo compounds were separated and solidified and thus obtained azo compounds had variable colour shades depending on their respective diazonium salts. The possibility of applying these azo compounds as in-situ azo dyes on 100% cotton and ready-madeinsoluble disperse azo dyes using HTHP conditions on 100% polyester, 100% nylonand 100% wool were investigated. Different azo compounds produced different colourshades on different fabric types as well as on the same fabric type. Optimisation of dye bath conditions to improve the take up of polyphenols by cotton using the in-situ application of azo dyes was also carried out. The colours produced on cotton were not very bright and showed moderate colour fastness to washing, good colour fastness to rubbing while the brilliant colours produced on polyester showed good to very good wash, rub and sublimation fastness, after reduction clearing. The colour depth and fastness on nylon and wool were better than those on polyester. The light fastness of all the azo dyed samples was poor and should be improved using suitable after treatments. The percentage yield of polyphenols for both used and unused black tealeaves and the percentage yield of different azo compounds obtained from unused black tea leaves were calculated. The study was basically carried out with the aim of investigating the traditional dyeing techniques and indigenous dye producing plant sources in Sri Lanka and to assess the possibility of using polyphenols from one of the selected plant resources. Tea, which is abundantly available as tea waste (dust) from factories and brewed tea leaves fromdomestic sources was selected as the natural source of dye or dye intermediate for textile dyeing

Print vs. electronic : user preferences for information resources : a comparative study

Though University libraries have positioned themselves as the main vehicles for the organization, access, distribution and use of knowledge, current library services will eventually be inadequate to keep pace with the demands and expectations of modern library users. Therefore, this study is focused on the assessment of users preferences for electronic and print information resources available in Sri Lankan University Libraries

Tea polyphenols as an indigenous natural plant resource in preparation of azo dyes for dyeing textiles

For thousands of years. until as recently as the discovery ofthe first synthetic dye in 1RS6. all colouring substances were of natural (vegetable. animal, lichen and mineral) origin. After the discovery of first synthetic dye, there was a gradual decrease in the use of natural dyes. which were more expensive and in many ways more difficult to use. Today. many of the natural dyes have been replaced by synthetic dyes. The major problem threatening the textile industry today is the environmental pollution, arising out of the wet processing of the textiles. The production of synthetic dyes involves many violent reactions. using. manv hazardous petroleum based primary chemicals as well as the production of hazardous intermediates. Therefore it is high time that the over utilization of synthetic dyestuffs should be thought about in the context of health of the people and environment. Natural dvcs extracted or developed from natural resources exhibit better biodegradability. higher compatibility with the environment and also a lower toxicity and allergic reactions not to mention the unique and fascinating colours