Browsing by Subject "engineering"
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- ItemOpen AccessAn investigation into dynamical bandwidth management and bandwidth redistribution using a pool of cooperating interfacing gateways and a packet sniffer in mobile cloud computing(2021) Shuuya, Lukas; Murgu, AlexandruMobile communication devices are increasingly becoming an essential part of almost every aspect of our daily life. However, compared to conventional communication devices such as laptops, notebooks, and personal computers, mobile devices still lack in terms of resources such as processor, storage and network bandwidth. Mobile Cloud Computing is intended to augment the capabilities of mobile devices by moving selected workloads away from resource-limited mobile devices to resource-intensive servers hosted in the cloud. Services hosted in the cloud are accessed by mobile users on-demand via the Internet using standard thick or thin applications installed on their devices. Nowadays, users of mobile devices are no longer satisfied with best-effort service and demand QoS when accessing and using applications and services hosted in the cloud. The Internet was originally designed to provide best-effort delivery of data packets, with no guarantee on packet delivery. Quality of Service has been implemented successfully in provider and private networks since the Internet Engineering Task Force introduced the Integrated Services and Differentiated Services models. These models have their legacy but do not adequately address the Quality of Service needs in Mobile Cloud Computing where users are mobile, traffic differentiation is required per user, device or application, and packets are routed across several network domains which are independently administered. This study investigates QoS and bandwidth management in Mobile Cloud Computing and considers a scenario where a virtual test-bed made up of GNS3 network software emulator, Cisco IOS image, Wireshark packet sniffer, Solar-Putty, and Firefox web browser appliance is set up on a laptop virtualized with VMware Workstation 15 Pro. The virtual test-bed is in turn connected to the real world Internet via the host laptop's Ethernet Network Interface Card. Several virtual Firefox appliances are set up as endusers and generate traffic by launching web applications such as video streaming, file download and Internet browsing. The traffic generated by the end-users and bandwidth used is measured, monitored, and tracked using a Wireshark packet sniffer installed on all interfacing gateways that connect the end-users to the cloud. Each gateway aggregates the demand of connected hosts and delivers Quality of Service to connected users based on the Quality of Service policies and mechanisms embedded in the gateway. Analysis of the results shows that a packet sniffer deployed at a suitable point in the network can identify, measure and track traffic usage per user, device or application in real-time. The study has also demonstrated that when deployed in the gateway connecting users to the cloud, it provides network-wide monitoring and traffic statistics collected can be fed to other functional components of the gateway where a dynamical bandwidth management scheme can be applied to instantaneously allocate and redistribute bandwidth to target users as they roam around the network from one location to another. This approach is however limited and ensuring end-to-end Quality of Service requires mechanisms and policies to be extended across all network layers along the traffic path between the user and the cloud in order to guarantee a consistent treatment of traffic.
- ItemOpen AccessCharacterisation of the hydantoin-hydrolysing activity of pseudomonas putida strain RUKM3s and development of biocatalyst for amino acid production(2005) Bulawayo, Bernard T; Burton, StephanieThis study tested the hypothesis that the hydantoin-hydrolysing enzymes of a novel Pseudomonas putida, RUKM3s, with high-levels of activity of a non-stereoselective hydantoinase, and an L-selective N-carbamyl amino acid amidohydrolase (NCAAH), could be optimally extracted, partially purified for characterisation, stabilised by immobilisation, and applied as a biocatalyst for production of amino acids from 5-mono-substituted hydantoin substrates. Experiments were devised to optimise conditions for the production of RUKM3s biomass with high levels of hydantoin hydrolysing activity, and to evaluate techniques of protein extraction, enzyme isolation, purification and characterisation. The NCAAH ofRUKM3s is a dimer of approximately 60 k:Da, .with two subunits of approximately 30 k:Da each. The hydantoinase · is approximately 210 kDa. Methods of enzyme immobilisation were investigated and operational parameters of the immobilised biocatalysts were evaluated. Stabilisation of biocatalysts by immobilisation revealed that among five methods of immobilisation used, covalent coupling to Eupergit® C provided the most suitable biocatalyst formulation of the RUKM3s enzymes. A model of the hydantoinase reaction based on the stabilised biocatalyst was developed and tested by empirical studies in a bioreactor system. In the system, the high hydantoinase activity from RUK.M3s was coupled with the high NCAAH activity of a mutant Agrobacterium tumefaciens strain, RUOR-PNI, to enhance the overall product yield. It was . demonstrated that the combined bioreactor system could achieve close to 100 % conversion yields of amino acid, operating in a continuous substrate-feed mode.
- ItemOpen AccessDehydration of apple rings(1971) Promnitz, Richard Henry George; Carr, A D; Buhr, H OThe effect of air humidity and velocity, tray surface and ring thickness, on the drying rates of apple rings, is reported. Drying rates for different apple slice thicknesses are correlated with the total moisture content of the fruit and the air relative humidity. Also reported are results on the simulation, both experimental and computational, for the parallel-flow industrial dehydrator drying process.
- ItemOpen AccessDesign of a backend system to integrate health information systems – case study: ministry of health and social services (MoHSS)-Namibia(2021) Shoopala, Anna-Liisa; Mwangama, JoyceInformation systems are the key to institution organization and decision making. In the health care field, there is a lot of data flow, from the patient demographic information (through the electronic medical records), the patient's medication dispersal methods called pharmaceutical data, laboratory data to hospital organization information such bed allocation. Healthcare information system is a system that manages, store, transmit and display healthcare data. Most of the healthcare data in Namibia are unstructured, there is a heterogeneous environment in which different health information systems are distributed in different departments [1][2]. A lot of data is generated but never used in decision-making due to the fragmentation. The integration of these systems would create a flood of big data into a centralized database. With information technology and new generation networks becoming a called for innovations in every day's operations, the adaptations of accessing big data through information applications and systems in an integrated way will facilitate the performances of practical work in health care. The aim of this dissertation is to find a way in which these vertical Health Information System can be integrated into a unified system. A prototype of a back-end system is used to illustrate how the present healthcare systems that are in place with the Ministry of Health and Social Service facilities in Namibia, can be integrated to promote a more unified system usage. The system uses other prototypes of subsystems that represent the current systems to illustrate how they operate and, in the end, how the integration can improve service delivery in the ministry. The proposed system is expected to benefit the ministry in its daily operations as it enables instant authorized access to data without passing through middlemen. It will improve and preserve data integrity by eliminating multiple handling of data through a single data admission point. With one entry point to the systems, manual work will be reduced hence also reducing cost. Generally, it will ensure efficiency and then increase the quality of service provided.
- ItemOpen AccessLow cost fencing material for a pre-school in Lavender Hill(2011-07) Mazwai, KonkeThis project has been proposed by the UCT Knowledge Partnership Project. This institution is aimed at providing assistance to under-privileged communities in the Western Cape. A pre-school fence material which is low cost is to be investigated. The following criterions were set to be met for the material: -The material is to have no fuel usage value such as wood, which can be burnt for space heating -The material is to have no scrap metal value such as steel and wire fencing material as this easily gets stolen. -The material is not to block visibility which harbors criminal activity in the area. Fences such as concrete slabs and brick block visibility. The materials considered in this project are: -Various plastic polymer materials -Plastic Lumber composite material -Recycled Plastic -Rubber reinforced concrete Plastic lumber and recycled plastic HDPE were considered for use in the fence material. After considering the available fence components and loading on the fence, 100 x 100 mm cross section plastic lumber and recycled plastic section were chosen to be used. The fence design was based on existing patents which were modified. A design showing the meter of the fence was designed and is shown in the document.
- ItemOpen AccessLow-cost fencing for a pre-school in Lavender Hill(2011-07) UCT Knowledge Co-opThis is an engineering project that focused on providing assistance to the New World Foundation's community centre in Lavender Hill in the Western Cape. This community faces many challenges from unemployment to high crime rates. The NWF pre-school faced the challenge of having their fence stolen on several occasions and therefore needed a low-cost, effective solution to this problem.
- ItemOpen AccessLow-cost fencing material for pre-school in low income area(2011-07) Mazwai, KonkeResearch into new material and design for a pre-school fence that doesn't get stolen, can't hurt children and does not limit visibility.
- ItemOpen AccessMedicine and the Arts Week 4 - Cultivating creative thoughts(2015-01-21) Baghai-Wadji, AlirezaIn this video, Alireza Baghai-Wadji, and electrical engineer, explores various questions related to creativity, its origins, and the idea that creativity is an ability that can be acquired. He also he discusses his ideas about the converging worlds of physics, philosophy, and neuroscience in order to get us thinking about the processes that drive our most inventive thinking. This is the second video in Week 4 of the Medicine and the Arts Massive Open Online Course.
- ItemOpen AccessMicrobial solvent formation revisited by comparative genome analysis(2017) DYrre, PeterAbstract Background Microbial formation of acetone, isopropanol, and butanol is largely restricted to bacteria belonging to the genus Clostridium. This ability has been industrially exploited over the last 100 years. The solvents are important feedstocks for the chemical and biofuel industry. However, biological synthesis suffers from high substrate costs and competition from chemical synthesis supported by the low price of crude oil. To render the biotechnological production economically viable again, improvements in microbial and fermentation performance are necessary. However, no comprehensive comparisons of respective species and strains used and their specific abilities exist today. Results The genomes of a total 30 saccharolytic Clostridium strains, representative of the species Clostridium acetobutylicum, C. aurantibutyricum, C. beijerinckii, C. diolis, C. felsineum, C. pasteurianum, C. puniceum, C. roseum, C. saccharobutylicum, and C. saccharoperbutylacetonicum, have been determined; 10 of them completely, and compared to 14 published genomes of other solvent-forming clostridia. Two major groups could be differentiated and several misclassified species were detected. Conclusions Our findings represent a comprehensive study of phylogeny and taxonomy of clostridial solvent producers that highlights differences in energy conservation mechanisms and substrate utilization between strains, and allow for the first time a direct comparison of sequentially selected industrial strains at the genetic level. Detailed data mining is now possible, supporting the identification of new engineering targets for improved solvent production.
- ItemOpen AccessPredictions of leachate generation from minerals processing waste deposits(1995) Davies, Graham Mark; Petrie, JimThe minerals processing industry in South Africa produces significant tonnages of waste material which are disposed of commonly in dedicated waste depositories. These deposits pose a potential to pollute the environment if leachate is generated within the deposit and released to the surroundings. Leachate generation is generally investigated using laboratory columnar experiments which attempt to mimic the physical and chemical processes which occur in the deposit. These experiments, termed lysimeter experiments, are time consuming in that they typically last for at least a few months and can last for up to three years. Lysimeter experiments are also costly to conduct. Because of restrictions such as these, relatively few deposits have been characterised to determine the leachate which they generate and thus the risk which they pose to the environment. There is an urgent need to be able to estimate the environmental risks associated with existing waste deposits. The first step towards assessing this risk would be an ability to predict leachate generation within a specific deposit. Such an ability could be used to identify which of the existing deposits produce significant leachate and thus pose a potential hazard to the environment. Equally, if leachate generation from new deposits could be estimated as a function of waste material and characteristics of the waste deposit, this information could be used to improve the engineering design of waste deposits. The work presented in this thesis involved identifying suitable modelling strategies which could be used to determine leachate generation within waste deposits which contain waste material typical of that produced by the minerals processing industry. Two modelling strategies have been investigated. The first modelling strategy involved a macroscopic model in which all effects such as intrinsic chemical kinetics, intra-particle diffusion, external mass transfer and hydrodynamic considerations are lumped into a single parameter. The result of this approach is an effective reaction rate for the release of hazardous constituents from a volume element of the waste deposit. The effective reaction rate is determined by fitting the model to experimental data based on lysimeter tests. The main advantage of this model is that it eliminates the need for a detailed understanding of the individual factors which contribute to leachate generation. This model was investigated both for its inherent simplicity and for use in cases where insufficient information with respect to the intrinsic chemical reaction rates, intra-particle diffusion, external mass transfer or hydrodynamic aspects exist. The main disadvantage of this model is that it has a limited predictive ability in that the individual significance of any one factor which contributes to leachate generation cannot be determined. For this reason a second, more detailed model, termed the heterogenous columnar model, has also been investigated. The heterogenous columnar model describes the release of hazardous constituents at the single particle level and relates this information to the overall leachate generation within the deposit. This is achieved by calculating the release of hazardous constituents from the size distribution of particles to the bulk fluid between these particles. The release of hazardous constituents from individual particles is determined by making use of a particle-scale chemical reaction 'model. This particle-scale model is sufficiently detailed to be able to determine the relative contribution to the overall release of hazardous constituents from the particles of intrinsic chemical kinetics of the reactions to the effects of diffusion of the fluid reagent into each particle. The heterogenous columnar model can also be used to determine whether the effective rate of release of hazardous constituents from the particles (which include intrinsic kinetic and diffusional contributions) or the flow of fluid reagent through the deposit limits the release of hazardous constituents from the deposit. This information can be used to determine the main factors which affect the release of hazardous constituents from waste deposits and can thus be used to improve the design of waste deposits. Probably the most important attribute of the heterogenous columnar model is that methods have been investigated to determine the model parameters from a simple continuously stirred tank reactor (CSTR) type experiment. The ability of the heterogenous columnar. model to predict leaching behaviour has been investigated using data on precious metal leaching found in the literature. The results are encouraging in that the model can accurately predict the leaching behaviour of precious metals. A preliminary investigation into determining suitable particle-scale model parameters for a sample of waste from a CSTR experiment has been conducted. This too has yielded encouraging results. However, the application of using the heterogenous columnar model using these parameters to describe leachate generation within waste deposits or lysimeter experiments still needs to be demonstrated. Once the heterogenous columnar model has been verified against data pertaining to leachate generation from a waste deposit it may start to provide the minerals processing industry with the information which it so desperately requires in order to dispose of wastes in a manner which minimises the impact on the environment.
- ItemOpen AccessSocial development for the Cape Flats: an alternative planning structure(1975) Paton, Hugh M; Chapman, RAn initial analysis into the present problems which will affect the future growth of the Western Cape resulted in the conclusion that the situation of the Coloured population is the factor most urgently requiring positive planning resolutions. Understanding the area's problems leads one to conclude that the main thrusts must be directed towards increased opportunities for the residents to fulfil their potential, and towards a greater involvement in the decisions made about their future. The arrangement of the thesis was thus developed around the three interrelated notions of administrative structure, human resources and social development, physical and economic resources. An unbound 'process diagram’ is provided in the back cover to facilitate an understanding of the sequence adopted. The administrative and planning activities of various local authorities, particularly the Cape Town City Council, were investigated with respect to the relationship between their actions and the causes of problems on the Flats. The complexity of social problems necessitated a consideration of the concept and the theory of social development. This was defined as the process whereby the individual and/or group is enabled to increasingly participate in and contribute to the growing flow of social transactions over time. By adopting Social Development as the goal for the Cape Flats and developing objectives for its six primary subsystems (housing, education, employment, recreation, community and civic), the subsequent form of the thesis was established.
- ItemOpen AccessThe effects of safety culture on project performance in high risk industries(2019) Isaacs, Zieyaad; Shaw, CorrinneProjects are undertaken at Koeberg Nuclear Power Station in South Africa to enhance safety and to contribute to the continuity of power supply in the country. These projects are undertaken in an industry that is regarded as a high risk due to the potential consequence of a nuclear accident. Focus is thus placed on safety culture to prevent such accidents from taking place. Since safety is a key performance indicator in these high-risk industries, and projects are undertaken to improve the overall performance of such organizations, the role which safety culture has on project performance would be of interest. This study investigates how safety culture influences project performance and identifies the respective elements that collectively interact in contributing towards successful project outcomes in the context of Koeberg Nuclear Power Station. The study has found that - Safety culture plays a vital role in safety performance which is a recognized performance indicator of projects in high risk industries. Safety culture itself was found to consist of the elements of safety performance, personal values to safety, safety leadership, safety related interpersonal relations, proactivity to safety, commitment to safety and continuous improvements to safety. These elements with emphasis on safety were related to the project management knowledge areas of Time, Scope, Risk, Quality, Human Resource and Communication Management. The project managers competencies are also included amongst these elements which respectively interact with one another to influence the level of safety culture in a project. The study has revealed that these elements should be worked at by all departments involved in a project to allow the required performance criteria to be achieved. In addition, it reveals that a good safety culture provides flexibility in addressing changing requirements in a project.