Flow in porous media of oil-water systems

Fluid flow behaviour in porous media is a conundrum. Therefore, this research is focused on filtration-volumetric characterisation of fractured-carbonate sediments, coupled with their proper simulation. For this reason, at laboratory rock properties such as pore volume, permeability and porosity are measured, later phase permeabilities and oil recovery in function of flow rate are assessed. Furthermore, the rheological properties of three oils are measured and analysed. Finally based on rock and fluid properties, a model using COMSOL Multiphysics is built in order to compare the experimental and simulated results. The rock analyses show linear relation between flow rate and differential pressure, from which phase permeabilities and pressure gradient are determined, eventually the oil recovery under low and high flow rate is established. In addition, the oils reveal thixotropic properties as well as non-Newtonian behaviour described by Bingham model, consequently Carreau viscosity model for the used oil is given. Given these points, the model for oil and water is built in COMSOL Multiphysics, whereupon successfully the reciprocity between experimental and simulated results is analysed and compared. Finally, a two-phase displacement model is elaborated.

Thermal modelling of commercial lithium-ion batteries

The accelerating adoption of electrical technologies in vehicles over the recent years has led to an increase in the research on electrochemical energy storage systems, which are among the key elements in these technologies. The application of electrochemical energy storage systems for instance in hybrid electrical vehicles (HEVs) or hybrid mobile working machines allows tolerating high power peaks, leading to an opportunity to downsize the internal combustion engine and reduce fuel consumption, and therefore, CO2 and other emissions. Further, the application of electrochemical energy storage systems provides an option of kinetic and potential energy recuperation. Presently, the lithium-ion (Li-ion) battery is considered the most suitable electrochemical energy storage type in HEVs and hybrid mobile working machines. However, the intensive operating cycle produces high heat losses in the Li-ion battery, which increase its operating temperature. The Li-ion battery operation at high temperatures accelerates the ageing of the battery, and in the worst case, may lead to a thermal runaway and fire. Therefore, an appropriate Li-ion battery cooling system should be provided for the temperature control in applications such as HEVs and mobile working machines. In this doctoral dissertation, methods are presented to set up a thermal model of a single Li-ion cell and a more complex battery module, which can be used if full information about the battery chemistry is not available. In addition, a non-destructive method is developed for the cell thermal characterization, which allows to measure the thermal parameters at different states of charge and in different points of cell surface. The proposed models and the cell thermal characterization method have been verified by experimental measurements. The minimization of high thermal non-uniformity, which was detected in the pouch cell during its operation with a high C-rate current, was analysed by applying a simplified pouch cell 3D thermal model. In the analysis, heat pipes were incorporated into the pouch cell cooling system, and an optimization algorithm was generated for the estimation of the optimalplacement of heat pipes in the pouch cell cooling system. An analysis of the application of heat pipes to the pouch cell cooling system shows that heat pipes significantly decrease the temperature non-uniformity on the cell surface, and therefore, heat pipes were recommended for the enhancement of the pouch cell cooling system.

Benefits and challenges of Enterprise Resource Planning for Pakistani SMEs

Enterprise resource planning (ERP) software is used to combine all the functions happening inside the organization with the help of one software. All the data is centralized which makes it easy to manage information for all participants. The literature on ERP is studied thoroughly the whole process of adoption till the implementation and final evaluations. But studies that focus on small and medium sized enterprises are limited in number when compared to the large scale enterprises. In case of Pakistan, research is very limited. In this thesis, the author tries to analyze the current status of SMEs usage of ERP system. The benefits obtained and challenges faced by SMEs of Pakistan are studied. Framework presented by Shang and Seddon (2000) is used to understand the benefits obtained by the SMEs in Pakistan. This is a comprehensive framework that classifies the benefits obtained by the ERP adoption, into five categories: operational benefits, managerial benefits, Strategic benefits, IT benefits, and Organizational benefits. The results show that SMEs of Pakistan are also getting many benefits after adoption of ERP. Most of the firms had implemented SAP software. Operational benefits were mentioned by all the firms. The most important benefits were report generation, quick access to critical information, better product and cost planning. Respondents also mentioned that they had reduced corruption as a result of ERP implementation. It is also an important benefit considering high corruption rate in Pakistan. Along with benefits, challenges faced by Pakistani SMEs included infrastructure problems like electricity, difficulties with integration of one module with other module, costs of adoption and lack of skilled ERP consultants. Further studies in this regard can be conducted on cloud based ERP which is fast growing all around the world.