Development of a Rational Procedure for Shear Design in Structural Concrete

Over the last century, the design for shear in reinforced concrete beams has been uncertain. The reason for this uncertainty is the lack of clear understanding of the true nature of load carrying mechanism. Researchers around the world have developed several shear design procedure as a remedy to this uncertainty. Most of them are empirical and some are rational which use various mathematical representations of load carrying mechanism. Almost all of these mathematical models are complicated and accuracy of is rather low compared to empirical methods. With the advancement of concrete technology and introduction of new methods, the improvement of accuracy of shear design methods is rather unmatchable when compared with flexural design. However, some of the new shear design methods were adopted by codes of practice and the design formulae were modified by introducing various empirical factors based on test. So the shear design has now become very much empirical. Some of the developed rational methods give good representation of the load carrying mechanism of beams. The method proposed here with the objective of developing a rational yet simple method, also assumes the load carrying mechanism of a beam as a truss. The tension carrying member represents the stirrups and the concrete portion is represented by compression member. For this proposed=method, the compression carrying concrete member is idealized as a cylindrical element applied with axial compression. The behavior ~of this idealized cylinder is modeled by using mathematical technique'S like Isotropic and Anisotropic analysis. This developed method is ..•compared with several key codes of practice using available test data for accuracy. It is found that the proposed method is giving sound representation of the test results compared with most other codes of practice. According to the comparison, it is clear that this method is only second to Japanese code of practice.Senate Research Gran

Green manuring for tropical organic cropping – A comparative analysis

Green manuring is an essential component of tropical organic farming. Field studies evaluated the use of three legumes as in situ or ex situ green manures, along with a nonlegume green manure and a control to ascertain their impacts on soil properties and yields of maize and mung bean grown in major (wet) and minor (dry) seasons. In situ green manuring, especially with legumes, had the most beneficial impact on soil properties, while with ex situ methods, the use of leaves alone improved soil properties. Yields were increased to a greater extent by green manuring in the minor season, and the in situ system proved to be more beneficial. In ex situ green manuring, greater benefits were obtained by the application of leaves alone. The impact of different green manures and their application methods is presented

On signalling over through-silicon via (TSV) interconnects in 3-D integrated circuits.

This paper discusses signal integrity (SI) issues and signalling techniques for Through Silicon Via (TSV) interconnects in 3-D Integrated Circuits (ICs). Field-solver extracted parasitics of TSVs have been employed in Spice simulations to investigate the effect of each parasitic component on performance metrics such as delay and crosstalk and identify a reduced-order electrical model that captures all relevant effects. We show that in dense TSV structures voltage-mode (VM) signalling does not lend itself to achieving high data-rates, and that current-mode (CM) signalling is more effective for high throughput signalling as well as jitter reduction. Data rates, energy consumption and coupled noise for the different signalling modes are extracted

Domestic Resource Mobilisation in the SEACEN Countries

This study attempts to answer the following questions with regard to member SEACEN countries: "what is the level of savings?", "what determines savings?", and "what can be done to increase savings?". These questions are asked in the light of the fact that growing debt burdens, rising public sector spending and the limitations of foreign direct investment have refocused initiatives on new strategies in tapping domestic resources in the SEACEN countries. The study focuses on the nature and the pattern of savings mobilisation and the role of the financial system and financial reforms in mobilising domestic savings. The findings confirmed the positive relation between savings and the level of financial intermediation and development. This study is a collaborative project between the member central banks and the monetary authorities and The SEACEN Centre.

Extending systems-on-chip to the third dimension : performance, cost and technological tradeoffs.

Because of the today's market demand for high-performance, high-density portable hand-held applications, electronic system design technology has shifted the focus from 2-D planar SoC single-chip solutions to different alternative options as tiled silicon and single-level embedded modules as well as 3-D integration. Among the various choices, finding an optimal solution for system implementation dealt usually with cost, performance and other technological trade-off analysis at the system conceptual level. It has been identified that the decisions made within the first 20% of the total design cycle time will ultimately result up to 80% of the final product cost. In this paper, we discuss appropriate and realistic metric for performance and cost trade-off analysis both at system conceptual level (up-front in the design phase) and at implementation phase for verification in the three-dimensional integration. In order to validate the methodology, two ubiquitous electronic systems are analyzed under various implementation schemes and discuss the pros and cons of each of them

Issues in resolution and build size scaling of additive manufacturing technologies

In this review, scaling issues in additive manufacturing (AM) processes are discussed based on multiple factors. Scaling issues arise mainly due to design and control of the AM system and also while attempting to achieve desired accuracy. Based on current AM systems available commercially, we identified scaling issues that can potentially challenge the build feasibility and accuracy while moving in geometrical and build resolution length scales. Inherent limitations of multiple AM processes are discussed based on these aspects and challenges while implementing these technologies in multiple length scales are identified through this work. Potential remedies for such scaling issues are also presented based on current progressing research in AM.   

A simple cleaning machine for mattress fibre

A simple low cost cleaning machine for mattree fibre was designed and manufactured by the coconut processing board in order to get rid of dust in dry mattree fibre. This machine is described with tables ro indicate how the particular design came to be considered the most suitable for the purpose. The conditions under which it should be operated to give the best results are indicated

Crop damage by Asian elephant (Elephas maximus) in Ekgaloya and Dewalahinda areas in Ampara District, Eastern province, Sri Lanka

Article Details: Received: 2020-04-21 | Accepted: 2020-09-04 | Available online: 2021-03-31https://doi.org/10.15414/afz.2021.24.01.47-54Sri Lanka is one of the Asian countries to support a considerable number of wild elephants mainly in the dry zone of the country. But today elephants have become one of the most seriously endangered large mammals in Sri Lanka and the world as well. Agricultural crop damage by elephants has become a most common and serious problem across the elephant range in Sri Lanka due to negative interaction of people and the elephants. Eastern province is one of such areas where severe crop damage by wild elephants could be observed. In these areas, most of the directly affected families are having low income level. For this common problem, still there is no proper mitigation plans to lower the impacts. Therefore, this study focused on the analysis of economic losses to cultivated crops, identify the most vulnerable crop species and suggest viable control measures to minimize this problem to a certain extent in the area. This study was carried out in two villages within one cropping season under two stages. Household survey including randomly selected 50 villagers from each village was conducted. Highest crop damage incidents were recorded in Dewalahinda area. Of the widely grown crop varieties, maize (Zea mays) and paddy (Oryza sativa) are subjected to heavy damage in both villages. Paddy and maize were reported as damage crop species by wild elephants in Ekgaloya and 19 households (out of 33) suffered due to that crop raiding incident. Out of 38 crop damage incidents in Dewalahinda, 28 households reported damages in maize and 26 household reported damages in paddy. Wild elephants have shown a least interest on some crop varieties such as chilli (Capsicum annum), ladies’ finger (Hibiscus esculentus) and peanut (Arachis hypogaea).  But these crop fields were heavily damaged by elephants as they walk across these fields. In both villages, the harvesting period seemed to be affected more by crop damages than other times. However, the post harvesting period was also affected occasionally especially in stored paddy.Keywords: endangered, socio-economic, cropping season, vulnerable crop species, Macroscopic analysisReferencesBandara, R. (2010). Willingness to pay for conservation of Asian Elephants in Sri Lanka. The Economics of Ecosystems & Biodiversity, 1–6. http://www.teebweb.org/wp-content/uploads/2013/01/Human-elephant-conflict-mitigationthrough-insurance-scheme-Sri-Lanka.pdfBandara, R. and Tisdell, C. (2003). Comparison of rural and urban attitudes to the conservation of Asian elephants in Sri Lanka: Empirical evidence. Biological Conservation, 110(3), 327–342. https://doi.org/10.1016/S0006-3207(02)00241-0Bandara, R. and Tisdell, C. (2005). Changing abundance of elephants and willingness to pay for their conservation. Journal of Environmental Management, 76(1), 47–59. https://doi.org/10.1016/j.jenvman.2005.01.007Brown, J. L., Göritz, F., Pratt-Hawkes, N., Hermes, R., Galloway, M., Graham, L. H., Gray, C., Walker, S. L., Gomez, A., Moreland, R., Murray, S., Schmitt, D. L., Howard, J. G., Lehnhardt, J., Beck, B., Bellem, A., Montali, R. and Hildebrandt, T. B. (2004). Successful artificial insemination of an asian elephant at the national zoological park. Zoo Biology, 23(1), 45–63. https://doi.org/10.1002/zoo.10116Campos-Arceiz, A., Larrinaga, A.R., Weerasinghe, U.R., Takatsuki, S., Pastorini, J., Leimgruber, P., Prithiviraj, F. and Santamaría, L. (2008). Behavior Rather than Diet Mediates Seasonal Differences in Seed Dispersal by Asian Elephants. Ecology, 89(10), 2684-91. doi: https://doi.org/10.1890/07-1573.1de Silva, S. (2010). On predicting elephant population dynamics. Gajah, (33), 12–16.Ekanayaka, S., Campos-Arceiz, A., Rupasinghe, M., Pastorini, J. and Fernando, P. (2011). Patterns of crop raiding by Asian elephants in a human-dominated landscape in Southeastern Sri Lanka. Gajah, (34), 20–25. https://doi.org/10.5167/uzh-59040Fernando, P., Jayewardene, J., Prasad, T. and Hendavitharana, W. (2011). Current Status of Asian Elephants in Sri Lanka. Gajah, (35), 93–103. Hedges, S. and Gunaryadi, D. (2010). Reducing human-elephant conflict: Do chillies help deter elephants from entering crop fields? Oryx, 44(1), 139–146. https://doi.org/10.1017/S0030605309990093Hedges, S. and Gunaryadi, D. (2010). Reducing human-elephant conflict: Do chillies help deter elephants from entering crop fields? Oryx, 44(1), 139–146. https://doi.org/10.1017/S0030605309990093Lorimer, J. (2010). Elephants as companion species: The lively biogeographies of Asian elephant conservation in Sri Lanka. Transactions of the Institute of British Geographers, 35(4), 491–506. https://doi.org/10.1111/j.1475-5661.2010.00395.xPlotnik, J. M., De Waal, F. B. M. and Reiss, D. (2006). Self-recognition in an Asian elephant. Proceedings of the National Academy of Sciences of the United States of America. https://doi.org/10.1073/pnas.0608062103Pozo, R. A., Coulson, T., Mcculloch, G. A. S. and Songhurst, A. (2017). Chilli-briquettes modify the temporal behaviour of elephants, but not their numbers. Oryx, 53(1), 100– 108. DOI: https://doi.org/10.1017/S0030605317001235Santiapillai, C. and Read, B. (2010). Would masking the smell of ripening paddy-fields help mitigate humanelephant conflict in Sri Lanka? Oryx, 44(4), 509–511. https://doi.org/10.1017/S0030605310000906Santiapillai, C., Suva, A., Karyawasam, C., Esufali, S., Jayaniththi, S., Basnayake, M., Unantenne, V. and Wijeyamohan, S. (1999). Trade in Asian elephant ivory in Sri Lanka. Oryx, 33(2), 176–180. https://doi.org/10.1046/j.1365-3008.1999.00041.xSantiapillai, C., Wijeyamohan, S., Bandara, G., Athurupana, R., Dissanayake, N. and Read, B. (2010). An  assessment of the human-elephant conflict in Sri Lanka. Ceylon Journal of Science (Biological Sciences), 39(1), 21. https://doi.org/10.4038/cjsbs.v39i1.2350Shrestha, K. (2018). Zero tillage impacts on economics of  wheat production in far western Nepal. Farming & Management, 3(2). https://doi.org/10.31830/2456-8724.2018.0002.14Sukumar, R. (1989). Ecology of the asian elephant in southern india. i. movement and habitat utilization patterns. Journal of Tropical Ecology, 5(1), 1–8. https://doi.org/10.1017/S0266467400003175Survey Department of Sri Lanka. (1987). Map of Ekgal Oya and Devalahinda, 1 : 10,000. Geo Information, No 150, Kirula Road, Narahenpita, Colombo 05, Sri Lanka.Wang, L., Lin, L., He, Q., Zhang, J. and Zhang, L. (2007). Analysis of nutrient components of food for Asian elephants in the wild and in captivity. Frontiers of Biology in China, 2(3), 351– 355. https://doi.org/10.1007/s11515-007-0052-0Webber, C. E., Sereivathana, T., Maltby, M. P. and Lee, P. C. (2011). Elephant crop-raiding and human-elephant conflict in Cambodia: Crop selection and seasonal timings of raids. Oryx, 45(2), 243–251. https://doi.org/10.1017/S003060531000033