Structural Strength and Behaviour of Cylindrical Steel Sheet Roofing

The roof does not only protect the building and its occupants from the effects of weather, but it is also an architectural feature that gives the building a desired appearance. Profiled steel sheet zincalume is normally used in roof as covering materials, without any attention paid to its struchiral capability as a self-supporting medium. A self-supporting roofing element is a new; where profiled sheeting roof could run continuous lengths of roof spans without internal support. This roofing system saves material and construction cost by avoiding internal support. The aim of this research work is to study the possibility of using profiled steel sheet as self-supporting roofing elements for affordable housing. An analytical investigation using the finite element method was carried out on the structural strength and behavior of different types of self-supporting roofing elements. Five laboratory tests using 3 m spans, 0.42 mm thickness and different crown heights of 1.5, 1.0, 0.50, 0.25 and 0.125 m specimens were conducted for assessing the structural strength and behavior of roofing elements. Analytical study was camed out on the effect of shape, size, materials and support condition on the structural behaviour of the selected roofing element. The analytical investigation was extended for longer spans to explore the feasibility of using of profiled steel sheet as a self supporting roofing system in housing construction. In the analytical work, finite element models were generated and analyzed by using LUSAS software. The analytical study for the roofing elements showed that parabolic profiled roofing element with crown height 116 of span length was more efficient than others as a self-supporting element. The proposed self-supporting roofing element satisfied geometrical, buckling and material stability. Deflection was found to be the limiting criteria in design for self-supporting roofing element using profiled steel sheet. The presence of corrugation in the steel roofing element resulted in a significant improvement on the roofs structural performance compared to flat sheet element. Good agreement was found between the results from finite element analysis and those obtained experimentally. The FEM models predicted with a reasonable degree of accuracy the structural behavior of different types of roofing elements. It was observed that a parabolic shape roofing element with an optimum crown height could be used as a self- supporting roofing element for about 4 m and 8 m span lengths using 0.42 mm and 1.25 mm thick profiled steel sheet. On the basis of this investigation, parabolic self-supporting roofing elements using profiled steel sheet with optimum crown height could be used in housing construction

Relationship between Sustainable Environmental Practices and Sustainable Value Creation: A Conceptual Study on Readymade Garments Industry of Bangladesh

Because of the increasing level of industrial contamination the demand for sustainable products and raw materials aligned with the ecological pollution has been on the rise in this horizon. This study theoretically explores the impact of sustainable environmental practices on financial performance of Ready-made Garment (RMG) companies of Bangladesh following the growing literature linking corporate sustainable environmental performance with revenue development and profitability. Various sustainable environmental practices have diverse effects on firm’s performance, as the literature review suggests. From literature review this paper reports four key areas (community, employee, environment and governance) of sustainable practices for sustainable financial performance that would provide a useful and practical perspective on how companies can explore the sustainable agenda. Finally this paper concludes that companies should integrate environmental, social and governance issues to capture value in terms of revenue development and profitability for the companies. We recommend that the theoretical model that we have derived from literature review needs to validated and tested by future research

Reaching an Agreement for the Elimination of Child Labour from the Supply Chains

This article examines how child labour can be eliminated from various supply chains in Bangladesh. Reinforcing this issue is important to comply with international labour standards on child labour and to avoid potential trade sanctions of various types. Drawing upon the examples of other mechanisms to implement international labour standards particularly in a situation when domestic initiatives remain largely ineffective, it is argued that various local and international actors in the supply chains have a key role to play in actively enforcing this international standard to help support an economy free from the curse of child labour. This article proposes that an international legally binding agreement among global importers, unions, and local stakeholders to improve the child labour situation may provide the best mechanism to eliminate this problem from various supply chains in Bangladesh

Future strategic plan analysis for integrating distributed renewable generation to smart grid through wireless sensor network: Malaysia prospect

AbstractIntegration of Distributed Renewable Generation (DRG) to the future Smart Grid (SG) is one of the important considerations that is highly prioritized in the SG development roadmap by most of the countries including Malaysia. The plausible way of this integration is the enhancement of information and bidirectional communication infrastructure for energy monitoring and controlling facilities. However, urgency of data delivery through maintaining critical time condition is not crucial in these facilities. In this paper, we have surveyed state-of-the-art protocols for different Wireless Sensor Networks (WSNs) with the aim of realizing communication infrastructure for DRG in Malaysia. Based on the analytical results from surveys, data communication for DRG should be efficient, flexible, reliable, cost effective, and secured. To meet this achievement, IEEE802.15.4 supported ZigBee PRO protocol together with sensors and embedded system is shown as Wireless Sensor (WS) for DRG bidirectional network with prospect of attaining data monitoring facilities. The prospect towards utilizing ZigBee PRO protocol can be a cost effective option for full integration of intelligent DRG and small scale Building-Integrated Photovoltaic (BIPV)/Feed-in-Tariff (FiT) under SG roadmap (Phase4: 2016–2017) conducted by Malaysia national utility company, Tenaga Nasional Berhad (TNB). Moreover, we have provided a direction to utilize the effectiveness of ZigBee-WS network with the existing optical communication backbone for data importing from the end DRG site to the TNB control center. A comparative study is carried out among developing countries on recent trends of SG progress which reveals that some common projects like smart metering and DRG integration are on priority

Efficiency of plant growth-promoting rhizobacteria (PGPR) for the enhancement of rice growth

Plant growth-promoting rhizobacteria (PGPR) are beneficial bacteria that colonize plant roots and enhance plant growth by a wide variety of mechanisms. The use of PGPR is steadily increasing in agriculture and offers an attractive way to replacechemical fertilizers, pesticides, and supplements. Here, we have isolated and characterized the PGPR from the rhizosphere soil of rice field for the enhancement of growth of rice. Rhizosphere soils were collected from different areas of Mymensingh in Bangladesh. Ten isolates of bacteria, designated as PGB1, PGB2, PGB3, PGB4, PGB5, PGT1, PGT2, PGT3, PGG1 and PGG2, were successfully isolated and characterized. Subsequently, to investigate the effects of PGPR isolates on the growth of rice, a pot culture experiment was conducted. Prior to seeds grown in plastic pots, seeds were treated with PGPR isolates and seedlings were harvested after 21 days of inoculation. Isolates PGB4, PGT1, PGT2, PGT3, PGG1 and PGG2 induced the production of indole acetic acid (IAA), whereas only PGT3 isolate was able to solubilize phosphorus. Most of isolates resulted in a significant increase in plant height, root length, and dry matter production of shoot and root of rice seedlings. Furthermore, PGPR isolates remarkably increased seed germination of rice. Among the ten isolates, PGB4 and PGG2 were found almost equally better in all aspects such as dry matter production, plant height and root length of rice, and IAA production. Isolate PGT3 was also found to be promising in IAA production having an additional property of phosphate solubilization. The present study, therefore, suggests that the use of PGPR isolates PGB4, PGG2 and PGT3 as inoculant biofertilizers might be beneficial for rice cultivation as they enhanced growth of rice, and induced IAA production and phosphorus solubilization

Pro-poor intervention strategies in irrigated agriculture in Asia: poverty in irrigated agriculture: issues and options: Bangladesh

Irrigated farming / Poverty / Irrigation management / Water resource management / Policy / Planning / Institutions / Organizations / Local government / Non-governmental organizations / Legislation / Water users / Participatory management / Public sector / Water allocation / Cost recovery / Households / Income / Expenditure / Irrigation canals / Bangladesh

Strengthening of aluminium and stainless steel tubular sections with fibre-reinforced polymer

Strengthening of aluminium and stainless steel structural tubular sections using adhesive bonded fibre-reinforced polymer (FRP) subjected to web crippling has been investigated. Aluminium and stainless steel tubular sections may experience web crippling failure due to local concentrated loads or reactions. The web crippling strength can be enhanced by strengthening the webs of the sections in localized regions. The current international specifications of aluminium and stainless steel structures do not provide web crippling design rules for strengthening of tubular sections. Therefore, there is a need to develop safe and reliable web crippling design rules for FRP strengthened aluminium and stainless steel structures. An extensive test program was performed on FRP strengthening of aluminium and cold-formed stainless steel tubular sections subjected to web crippling. The test specimens consisted of 6061-T6 heat-treated aluminium alloy, ferritic stainless steel type EN 1.4003 and lean duplex type EN 1.4162 square and rectangular hollow sections. A total of 254 web crippling tests was conducted in this study. The tests were performed on eighteen different sizes of tubular sections which covered a wide range of web slenderness (flat portion of web depth-to-thickness) ratio from 6.2 to 62.2. The web crippling tests were conducted under the four loading conditions according to the American Specification and Australian/New Zealand Standard for cold-formed steel structures, namely End-Two-Flange, Interior-Two-Flange, End-One-Flange and Interior-One-Flange loading conditions. The investigation was mainly focused on the effects of different adhesive, FRP, surface treatment, widths of FRP plate and web slenderness of tubular sections for strengthening against web crippling. Six different adhesives, six different FRPs, two different surface treatments, three different widths of FRP plate were considered. It was found that the web crippling capacity of aluminium tubular sections are significantly increased due to FRP strengthening, especially for those sections with large value of web slenderness. The web crippling strength can be increased up to nearly 3 times using the appropriate adhesive and FRP for aluminium tubular sections, whereas the web crippling strength can be increased up to 51% and 76% for ferritic and lean duplex stainless steel tubular sections, respectively. The finite element models for FRP strengthened aluminium and stainless steel tubular structural members subjected to web crippling were developed and calibrated against the experimental results. The debonding between FRP plate and aluminium or stainless steel tubes was carefully modelled using cohesive element. It is shown that the calibrated model closely predicted the web crippling strengths and failure modes of the tested specimens. An extensive parametric study included 212 web crippling specimens was carried out using the verified finite element models to examine the behaviour of strengthened aluminium and stainless steel tubular sections subjected to web crippling. Design equations are proposed to predict the web crippling strengths of FRP strengthened aluminium and stainless steel tubular sections based on the experimental and numerical results. The web crippling strengths obtained from the tests and numerical analysis were compared with the design strengths calculated using the proposed equations. The reliability of the proposed design rules was evaluated using reliability analysis.published_or_final_versionCivil EngineeringDoctoralDoctor of Philosoph