Utilization of natural gas in remote locations necessitates on-site conversion of methane into liquid fuels or high value products. The first step in forming high value products is the production of ethylene and acetylene. Non-thermal plasmas, due to their unique nonequilibrium characteristics, offer advantages over traditional methods of methane reforming. Different kinds of non-thermal plasmas are being investigated for methane reforming. Parameters of these processes like flow rate, discharge size, temperature and other variables determine efficiency of conversion. An efficient process is identified by a high yield and low specific energy of production for the desired product. A study of previous work reveals that higher energy density systems are more efficient for methane conversion to higher hydrocarbons as compared to low energy density systems. Some of the best results were found to be in the regime of warm discharges. Thermal equilibrium studies indicate that higher yields of ethylene are possible with an optimal control of reaction kinetics and fast quenching. With this idea, two different glow discharge reactor systems are designed and constructed for investigation of methane reforming. A counter flow micro plasma discharge system was used to investigate the trends of methane reforming products and the control parameters were optimized to get best possible ethylene yields while minimizing its specific energy. Later a magnetic glow discharge system is used and better results are obtained. Energy costs lower than thermal equilibrium calculations were achieved with magnetic glow discharge systems for both ethylene and acetylene. Yields are obtained from measurements of product concentrations using gas chromatography and power measurements are done using oscilloscope. Energy balance and mass balances are performed for product measurement accuracy and carbon deposition calculations. Carbon deposition is minimized through control of the temperature and residence time conditions in magnetic glow discharges. Ethylene production is observed to have lower specific energies at higher powers and lower flow rates in both reactors. An ethylene selectivity of 40 percent is achieved at an energy cost of 458MJ/Kg and an input energy cost of 5 MJ/Kg of methane.

This study was undertaken to understand the effect of applied pressure on the performance of the lithium sulfur cathode. Compressible carbon based cathodes and novel nickel based cathodes were fabricated. For each cathode, pore volume and void volume were quantified and void fraction was calculated, compression under 0 to 2MPa was measured, and lithium-sulfur cells were assembled and cycled at pressures between 0 and 1MPa. The cathodes studied had void fractions in the range of 0.45 to 0.90. Specific discharge capacities between 200 and 1100 mAh/g under 1MPa were observed in carbon-based cathodes. Nickel-based cathodes showed increased specific discharge capacity of up to 1300 mAh/g, with no degradation of performance under pressure. The high correlation of specific discharge capacity and void fraction, in conjunction with previous work, strongly suggest that the performance of lithium-sulfur cathodes is highly dependent on properties that influence ionic mass transport in the cathode.

An investigation was conducted as a preliminary effort to develop a methodology to predict pore pressure in a rock formation during drilling, for all types of rocks and situations. Specifically, it was investigated whether or not the virgin pore pressure (the pore pressure of the undisturbed rock) can be determined at the drill bit from drilling and environmental parameters, as well as solid and pore fluid properties. Several drilling situations were analyzed to develop models relating pore pressure to drilling and environmental parameters, as well as solid and pore fluid properties. Three approaches to the modeling of such drilling situations were considered, which were used to predict pore pressure and compare the predictions to actual drilling data. The first approach used the concept of the effective stress in conjunction to the Mohr-Coulomb failure criterion. The second approach used the concept of the mechanical specific energy. The third approach made use of basic principles to relating virgin pore pressure to drilling and environmental parameters, as well as solid and pore fluid properties. This third approach resulted in the proposal of a more fundamental way of viewing mechanical specific energy (MSE) and the use of Biot's poroelasticity theory to describe the cutting process of rock. The first approach did not provide an adequate prediction of virgin pore pressure for all types of rocks and situations. The second approach showed promising results with limited actual drilling data. A sensitivity analysis of the model resulting from the third approach indicated that pore pressure, type of rock, and back rake angle of the cutter are the most significant factors affecting the energy required to break the rock. Moreover, rate of cutting stress, depth of cut, and type of pore fluid become significant factors of the cutting process only when a low-porosity, low-permeability rock is considered. It was concluded that there exists a relationship among pore pressure, drilling and environmental parameters, as well as solid and pore fluid properties. Therefore, it is possible in principle to determine the virgin pore pressure at the drill bit from drilling parameters, environmental parameters, and material properties. However, further work is required to establish a quantitative relationship among the significant parameters before a methodology to predict virgin pore pressure for all types of rocks and situations can be developed.

This thesis includes the theoretical part explaining problematic of centrifugal pumps, Y(Q) characteristics of these centrifugal pumps and stability of these characteristics, ways and conditions for stabilisation and adaptations heading to stabilisation.

This master's thesis includes theoretical analysis of characteristics of a centrifugal pump, conditions of stability of Y(Q) characteristic, calculation of characteristics ßč(ns), modifications leading to stabilization of a spiral body and a runner, a design of the spiral, the runner and follow-up computation in Fluent program.

Indiana University-Purdue University Indianapolis (IUPUI) / Design optimization of composite structures is of importance in the automotive, aerospace, and energy industry. The majority of optimization methods applied to laminated composites consider linear or simplified nonlinear models. Also, various techniques lack the ability to consider the composite failure criteria. Using artificial neural networks approximates the objective function to make it possible to use other techniques to solve the optimization problem. The present work describes an optimization process used to find the optimum design to meet crashworthiness requirements which includes minimizing peak crushing force and specific energy absorption for a square tube. The design variables include the number of plies, ply angle and ply thickness of the square tube. To obtain an effective approximation an artificial neural network (ANN) is used. Training data for the artificial neural network is obtained by crash analysis of a square tube for various samples using LS DYNA. The sampling plan is created using Latin Hypercube Sampling. The square tube is considered to be impacted by the rigid wall with fixed velocity and rigid body acceleration, force versus displacement curves are plotted to obtain values for crushing force, deceleration, crush length and specific energy absorbed. The optimized values for the square tube to fulfill the crashworthiness requirements are obtained using an artificial neural network combined with Multi-Objective Genetic Algorithms (MOGA). MOGA finds optimum values in the feasible design space. Optimal solutions obtained are presented by the Pareto frontier curve. The optimization is performed with accuracy considering 5% error.

Yes / The estimation of Polycrystalline Diamond Compact (PDC) cutters wear has been an area of concern for the drilling industry for years now. The cutter's wear has been measured practically by pulling the bit out for evaluation at the surface. It is important to find the right time for tripping out as this helps to avoid the fishing job and reduces the operational cost significantly. The prediction of the drilling performance is based on the interaction of cutter and rock. Several authors focused on the cutter-rock interface but only a few researchers tried to model the wear of the PDC bit cutters. The aim of this research is to understand the relationships between the rate of penetration (ROP) and the drilling variables per each foot, and then determine the overall bit efficiency for the whole drilling operation. A new mathematical model is derived to predict the PDC bit performance by considering the factors that were already not taken into account. These factors include rock strength, bit design, and bit hydraulic. The model investigates the effect of these parameters to estimate the abrasive cutters wear on the inner and the outer bit cones by deriving modified equations to calculate the mechanical specific energy (MSE), torque, and depth of cut (DOC) as a function of effective blades (EB). The model is used to forecast the bit cutters wear conditions in four wells in the oil fields located in Libya, which were drilled with three different PDC's sizes. The model enables the results to be compared to the actual bit cutters wear measured for inner and outer cones. The results are found that are well in agreement with the actual field data obtained in bit records. / Financial support from ministry of higher education in Libya.

Yes / Predicting the PDC bit performance during drilling operation is important for the cost effectiveness of the operation. The majority of PDC bits are assessed based on their performance that are relative to offset wells. Determination of mechanical specific energy (MSE) in real time and compare it with the known MSE for a sharp bit to assess the bit life has been utilized by several operators in the past. However, MSE still cannot be used to predict the bit performance in exploration wells and also it cannot assess the bit efficiency in the inner and outer cones. A more precise approach needs to be devised and applied to improve the prediction of bit life and the decision when to pull the bit out of the hole. Effective mechanical specific energy (EMSE) developed in this work is a new wear and performance predictive model that is to measure the cutting efficiency based on number of cutters, which contact the rock as a function of weight on bit (WOB), rotary speed (RPM), torque, and depth of cut (DOC). This model modifies the previous MSE model by incorporating such parameters and including detailed design of the bit, number of blades, cutter density, cutter size, and cutting angle. Using this approach together with the analysis of rock hardness, a level of understanding of how the drilling variables influence the bit performance in the inner and outer cone is improved, and a convenient comparison of the bit condition in the frame of the standard bit record is achieved. This work presents a new simple model to predict the PDC cutters wear using actual data from three sections drilled in three oil wells in Libya. It is found that the obtained results are in well agreement with the actual dull grading shown in the bit record.

A manufacturer would love to see progress in the optimization of a production system to maximize profit while maintaining the environmental regulations enacted by a government or society. Thus, a key performance indicator is needed to indicate how the system production is performing in monetary as well as environmental aspects. However, the manufacturer and the regulating body may not be aware of the environmental impacts associated with the production system as a key performance indicator like Overall Equipment Effectiveness (OEE) only implies the monetary aspects of the process. Therefore, there is a need to quantify the carbon emissions of the process and use it as a parameter that indicates profitability and environmental sustainability at the same time. From the public and policy-making body's point of view, they need a proper scale that can be used to track the compliance of the manufacturers with the environmental regulations. In this study, this carbon-based indicator (COEE) aims to discover a way of monitoring the progress of a process with environmental considerations. This study raises key questions that are constructive to each other to build a comparison of the ordinary OEE and environmental COEE. To do so a case study about the plastic process using an injection molding machine is conducted. The data used in this study was provided by the company named Good Solutions. Based on the data provided, the ordinary OEE of the machine for each shift is used to contrast with the result of the new modeled COEE. The RMSE for the given OEE of the machine was 13.424 while for COEE is 12.695. The RMSE of both OEEs indicates that the COEE can be used as an indicator for economic as well as environmental assessments.

Yes / The successful use of Reverse Osmosis (RO) process has increased significantly in water desalination, water treatment and food processing applications. In this work, the economic feasibility of a multi-stage RO process including both retentate and permeate reprocessing for the removal of chlorophenol from wastewater is explored using simulation and optimisation studies. Firstly, a mathematical model of the process is developed based on the solution diffusion model, which was validated using experimental chlorophenol removal from the literature, is combined with several appropriate cost functions to form a full model package. Secondly, for a better understanding of the interactions between the different parameters on the economic performance of the process, a detailed process simulation is carried out. Finally, a multi-objective optimisation framework based on Non-Linear Programming (NLP) problem is developed for minimising the product unit cost, the total annualised cost, the specific energy consumption together with optimising the feed pressure and feed flow rate for an acceptable level of chlorophenol rejection and total water recovery rate. The results clearly show that the removal of chlorophenol can reach 98.8% at a cost of approximately 0.21 $/m³.