Flexural Behaviour of Partially Prestressed Reinforced Baked Clay Beams

To provide shelter for slum dwellers of Pakistan, Reinforced Baked Clay (RBC) seems to be a possible option to replace Reinforced Cement Concrete (RCC) whose ingredients, i.e., aggregates and cement are costly in plains of the country. However, shear failure is a major problem observed in RBC beams. In addition, it is difficult to provide shear reinforcement in RBC beams, because it is time consuming and it does not contribute to resist shear stresses. In this study, a technique is presented to overcome problem of shear failure of RBC beams. The RBC beams were partially prestressed by post tensioning up to 60% of yield stress and were tested in three points loading. The results show that the RBC beams (i) exhibited flexural mode of failure without shear reinforcement, (ii) carried as much load as control RCC beam. This implies that by partial prestressing of RBC beams, there could be no need of shear reinforcement. This will result in saving of time and money

Autecological studies on Penicillium expansum

This thesis reports an autecological study on an apple rotting isolate of Penicillium expansum. The study was concerned with the survival and growth of the fungus in the soil, in the rhizospheres of apple, broad bean, maize and tomato, and in plant litter. P. expansum spores did not germinate in natural soil but could remain viable (68%) for up to one year at least. Spores germinated and developed to form conidia microcyclically in soil sterilized by autoclaving. Spores germinated in natural soil after the addition of nutrients, in the form of malt extract broth, indicating that nutrient deficiency might be one factor determining spore dormancy. Evidence was also obtained to show that non-volatile diffusible inhibitors of spore germination were present in natural soil. Heat treatment of natural soil at 80°C destroyed the inhibitory effect whereas treatment at 60°C had no effect although it destroyed most fungi and bacteria isolatable on Malt extract agar or Modified Hutchinson's agar. If nutrient deficiency were the inhibitory factor the release of nutrients from the micro-organisms killed by treatment at 60°C should have stimulated germination. Thus the activities of other micro-organisms in the soil, probably through the heat labile inhibitors they produced, were the main factors inhibiting germination. Some of the fungi which survived at 60°C for 6h were inhibitory to the growth of P. expansum in culture. The experiments on the survival of spores and of spore germination and growth in the rhizospheres of apple, broad bean, maize and tomato showed that spores could germinate and the fungus could grow in the rhizospheres of all three plant species. P. expansum was observed to grow occasionally closely attached to the root surfaces of broad bean, maize and tomato. It was never observed to invade the internal root tissues of tomato. The other two species were not investigated for the colonization of the internal tissue. The removal of the inhibition of spore germination in the rhizospheres could have been due to the effect of root exudates either serving as nutrients or as inactivators of inhibitory factors. The presence of P. expansum in the rhizospheres of tomato plants can affect plant growth to a limited extent. Inoculum in the rhizosphere slightly reduced stem height and total leaf area but had no effect on total dry matter, the number of leaves or the development of reproductive structures. Colonization by P. expansum of root and leaf litter from apple in the soil in the presence of other soil micro-organisms was very low. However it could survive in apple root tissues if the apple root was colonized before addition to the soil

Cloud adoption: a goal-oriented requirements engineering approach

The enormous potential of cloud computing for improved and cost-effective service has generated unprecedented interest in its adoption. However, a potential cloud user faces numerous risks regarding service requirements, cost implications of failure and uncertainty about cloud providers’ ability to meet service level agreements. These risks hinder the adoption of cloud computing. We motivate the need for a new requirements engineering methodology for systematically helping businesses and users to adopt cloud services and for mitigating risks in such transition. The methodology is grounded in goal-oriented approaches for requirements engineering. We argue that Goal-Oriented Requirements Engineering (GORE) is a promising paradigm to adopt for goals that are generic and flexible statements of users’ requirements, which could be refined, elaborated, negotiated, mitigated for risks and analysed for economics considerations. The methodology can be used by small to large scale organisations to inform crucial decisions related to cloud adoption. We propose a risk management framework based on the principle of GORE. In this approach, we liken risks to obstacles encountered while realising cloud user goals, therefore proposing cloud-specific obstacle resolution tactics for mitigating identified risks. The proposed framework shows benefits by providing a principled engineering approach to cloud adoption and empowering stakeholders with tactics for resolving risks when adopting the cloud. We extend the work on GORE and obstacles for informing the adoption process. We argue that obstacles’ prioritisation and their resolution is core to mitigating risks in the adoption process. We propose a novel systematic method for prioritising obstacles and their resolution tactics using Analytical Hierarchy Process (AHP). To assess the AHP choice of the resolution tactics we support the method by stability and sensitivity analysis

Water quality index assessment for the Skudai watershed and its tributaries

It is very important to develop a rehabilitation plan for the watersheds that have been degraded because of increased development activities and high urbanization. Identifying the most vulnerable parts of a watershed is challenging and can be done if water quality in the river was determined in different sections from the upstream to the downstream of a watershed. In this study, we delineated the Skudai watershed into 25 sub-watersheds using ArcGIS technique. Later, we identified tributaries in each sub-watershed. The sub-watersheds were grouped into three main categories, i.e. natural, semi-urban, and urban sub-watersheds. Water quality samples were collected at different tributaries from all three categories of sub-watersheds. The paper presents water quality analysis results. The Skudai River (natural part) was classified into natural sub-watershed. The Senai and Kempas rivers were classified into sub-urban watersheds while Melana and Danga rivers were classified into urban watersheds. The water quality index (WQI) for the Skudai River (Natural) was 95.2 and falls in class I category, i.e. clean. The Senai River had WQI of 84.5 and Class II category, i.e. slightly polluted. However, Kempas River which was also in the sub-urban watershed had calculated WQI of 54.4, in Class III and polluted. Melana River had was also polluted river with WQI of 68.8 (Class III). The Danga River was also polluted river with WQI value as 55.2

Simulation Studies Relating to Rudder Roll Stabilization of a Container Ship Using Neural Networks

International audienceRRS (Rudder Roll Stabilization) of Ships is a difficult problem because of its associated non-linear dynamics, coupling effects and complex control requirements. This paper proposes a solution of this stabilization problem that is based on an ANN (Artificial Neural Network) controller. The controller has been trained using supervised learning. The simulation studies have been carried out using MATLAB and a non-linear model of a container ship. It has been demonstrated that the proposed controller regulates heading and also controls roll angle very successfully

Water quality index for the Skudai River and its tributaries for identifying the problematic areas for better watershed management

It is very important to develop a rehabilitation plan for the watersheds that have been degraded because of increased development activities and high urbanization. Identifying the most vulnerable parts of a watershed is challenging and can be done if water quality in the river was determined in different sections from the upstream to the downstream of a watershed. In this study, we delineated the Skudai River watershed into 25 sub-watersheds using ArcGIS technique. Later, we identified tributaries in each sub-watershed. The subwatersheds were grouped into three main categories, i.e. natural, semi-urban, and urban subwatersheds depending on land use patterns. Water quality samples were collected at different tributaries from all three categories of sub-watersheds. The paper presents water quality analysis results. The Skudai River (natural part) was classified into natural sub-watershed as this sub-watershed was dominated with natural forest. The Senai and Kempas rivers were classified into sub-urban watersheds while Melana and Danga rivers were classified into urban watersheds. The water quality index (WQI) for the Skudai River (Natural) was 95.2 and falls in Class I category, i.e. clean. The Senai River had WQI of 84.5 and Class II category, i.e. slightly polluted. However, Kempas River which was also in the sub-urban watershed had calculated WQI of 54.5, in Class III and polluted. Melana River was also polluted river with WQI of 68.8 (Class III). The Danga River was also polluted river with WQI value as 55.2. Water quality in the direction of flow in the Skudai River was deteriorating because of some local pollutants entry on the way

Simulation studies relating to rudder roll stabilization of a container ship using neural networks

RRS (Rudder Roll Stabilization) of Ships is a difficult problem because of its associated non-linear dynamics, coupling effects and complex control requirements. This paper proposes a solution of this stabilization problem that is based on an ANN (Artificial Neural Network) controller. The controller has been trained using supervised learning. The simulation studies have been carried out using MATLAB and a non-linear model of a container ship. It has been demonstrated that the proposed controller regulates heading and also controls roll angle very successfully

Effect of Compaction during Casting on Anisotropic Compressive Strength of Baked Clay

Due to high cost of aggregates and cement in plains of Pakistan, there is an overwhelming need to investigate structural properties of Reinforced Baked Clay (RBC) as a possible substitute of Reinforced Cement Concrete (RCC) for construction of low cost houses. In this paper, direction dependent cube crushing strength of baked clay is investigated. For this purpose, baked clay beams were cast by applying compactive pressure of intensity from 0 to 7 MPa. The clay beams were fired at a temperature of 1000 °C. Cubes were cut from these baked clay beams. The cubes were tested for compressive strength in directions, i.e., parallel and perpendicular to casting layers. Anisotropy was observed in compressive strength of baked clay cubes. The baked clay showed anisotropic behaviour in compressive strength in general. However, the anisotropy in compressive strength was decreased by increasing compactive pressure at the time of casting of clay beams. Average crushing strength of baked clay cubes tested in a direction parallel to casting layers was found to be 35 MPa, and that of perpendicular to casting layers was 30 MPa. The magnitude of compressive strength of baked clay is 1.5 times higher than that of normal concrete

Reducing the Effect of Carbonation and Corrosion in Rice Husk Ash Concrete by Incorporating Polymer

Durability plays a vital role in life of a reinforced concrete structural member. To increase service life of a structure, it is important to reduce corrosion potential and carbonation attack. In order to reduce the corrosion and carbonation effect in concrete structures, various supplementary cementing materials are used. In this study, a novel composite is introduced to reduce corrosion potential and carbonation attack on Rice Husk Ash Polymer Modified Concrete (RHAPMC). An experimental work was conducted to check the behaviour of corrosion and carbonation attack in control concrete, cement was replaced with RHAPMC concrete at the ages of 30 and 180 days. The results indicate that the effect of corrosion potential and carbonation has been significantly reduced with the addition of polymer in the cement replaced concrete