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<p> Design and optimization of aircraft thermal management systems (TMS) is typically conducted by considering a single system architecture at steady-state conditions, using per?formance metrics such as bleed air flow rate, fuel burn flow rate, or total system mass. However, when trying to increase the overall performance of a legacy system or analyzing new system architectures, it can be difficult to identify how individual component or sub?system changes will propagate throughout the overall TMS. In this thesis, new knowledge and tools are presented that will advance the use of exergy-based design techniques for next generation aircraft thermal management systems (TMS). This is motivated by the fact that exergy destruction is a quantity that can be calculated for any subsystem or component, regardless of energy domain or function. The relationship between exergy destruction min?imization (EDM) and conventional design metrics is investigated and quantified. This is performed through the use of a steady-state analysis and by leveraging a high fidelity model of a complex TMS. It is shown that exergy destruction is not only sensitive to individual component parameters in a manner consistent with conventional performance metrics, but that due to its generalizability, it also captures how changes in one subsystem propagate throughout the overall TMS. Specifically, through a design case study, it is shown that minimizing system-wide exergy destruction rate (without an engine model) yields a similar engine fuel burn rate as when fuel burn is minimized directly, but also results in a signif?icantly lower system mass. Building on these results, a transient design and analysis tool for TMS is developed using a graph theoretic approach. The tool is used on a case study of an air cycle machine (ACM) and on an architecture enumeration case study for a notional TMS. The transient exergy-based analysis is shown to provide insight into how efficiently energy is used at a component level, and captures the differences in thermal performance between architectures. </p>

<p dir="ltr">This thesis details the development of a multidisciplinary design analysis (MDA) framework intended to evaluate a rocket-powered, reusable hypersonic vehicle. In particular, the analysis framework computes the design closure of a coupled system resembling Stratolaunch Systems’ Talon-A reusable hypersonic test vehicle. The resulting analysis framework differs from available literature due to its focus upon payload-related design considerations. The presented framework, too, avoids the use of proprietary technical information and/or export-controlled analysis tools. The framework’s geometric analysis, for example, employs a reverse-engineered geometry resembling Talon-A. An open-source aerothermal package, too, was selected to evaluate the vehicle’s aerothermodynamic characteristics. Quick-to-implement methods were prioritized to expedite the development of the MDA framework. Notably, a regression-based structural analysis model was used, as well as an interpolative thermal protection system (TPS) sizing procedure. A quasi-steady trajectory model, too, was implemented within the MDA framework, to determine the vehicle’s mission performance. The resulting analysis takes the form of a six-discipline MDA framework that can calculate, among other parameters, the vehicle’s cruise duration. Initial design closure results for a vehicle resembling Talon-A, using an assumed TPS size, are currently available. These results report an estimated total vehicle mass within thirty percent of Talon-A’s true gross mass, as well as a cruise duration of approximately 445 seconds. These design closure results were also evaluated under a perturbed specific impulse of ±10%, with a resulting change in cruise duration of ±12.3%. Results for a cruise-condition design exploration procedure were also obtained within a simplified, sequential analysis chain. These design exploration results report a maximum cruise lift-to-drag ratio of approximately four. Future work has been identified, too, including the integration of more rigorous analysis tools for use within future iterations of the MDA framework. Notably, these tools include an open-source optimal control library, as well as a physics-based TPS sizing tool</p>

Multidisciplinary design optimization (MDO) requires many designs to be evaluated while searching for an optimum. As a result, the calculations done to evaluate the designs must be quick and simple to have a reasonable turn-around time. This makes aerodynamic calculations in the transonic regime difficult. Running computational fluid dynamics (CFD) calculations within the MDO code would be too computationally expensive. Instead, CFD is used outside the MDO to find two-dimensional aerodynamic properties of a chosen airfoil shape, BACJ, at a number of points over a range of thickness-to-chord ratios, free-stream Mach numbers, and lift coefficients. These points are used to generate surrogate models which can be used for the two-dimensional aerodynamic calculations required by the MDO computational design environment. Strip theory is used to relate these two-dimensional results to the three-dimensional wing. Models are developed for the center of pressure location, the lift curve slope, the wave drag, and the maximum allowable lift coefficient before buffet. These models have good agreement with the original CFD results for the airfoil. The models are integrated into the aerodynamic and aeroelastic sections of the MDO code. / Master of Science

Roller conveyors are critical components in various industries for material handling, enabling the efficient transportation of items in assembly lines, warehouses, and distribution centers. Traditionally constructed from materials such as steel, aluminum, or plastic, roller conveyors are now being innovatively designed using composite materials. This study investigates the design, analysis, and optimization of roller conveyors utilizing composite materials to achieve weight reduction while maintaining or enhancing structural integrity and operational efficiency. Composite materials offer enhanced properties compared to their individual components. Typical composites include fibers like carbon, glass, or aramid within a matrix of epoxy resin, providing superior strength, corrosion resistance, and customization capabilities. The research employs finite element analysis (FEA) and other advanced modeling techniques to evaluate the performance of composite roller conveyors under various loading conditions. The findings suggest that using composite materials can significantly reduce the weight of roller conveyors, leading to decreased energy consumption, lower operational costs, and improved handling efficiency. The optimized design enhances productivity and contributes to sustainability by minimizing environmental impact. This thesis advances the understanding of composite-based roller conveyors, demonstrating their potential to replace conventional materials and achieve higher efficiency in industrial applications.

The main goals of this thesis are to design and examine heterogeneous antennas for different wireless applications of a wide variety of EM spectrum requirements: which includes WLAN 5.0 GHz, WLAN (2.45 GHz), UMTS (1.92-2.17 GHz), 2G, UMTS, LTE, ultra-wideband (UWB) applications, and MBAN applications (2.4 GHz). Various techniques for expanding bandwidth, enhancing performance, and balancing the operation have been examined through comprehensive simulated and physically fabricated models. Thereafter, a compact DRA, for UWB applications is examined. The combined resultant effects of asymmetric positioning of DRs (2, 3 and 4 Cylindrical elements), defected ground technique, dimensions, and profile of the aperture give RF designers detailed scope of the optimization process. More resonances are achieved, and the bandwidth is improved. The obtained results show that, an impedance bandwidth of 133.0%, which covers the Ultra­ Wideband band (3.6GHz - 18.0GHz), with a maximum power gain of 9dBi attained. In addition, a compact conformal wearable CPW antenna using EBG-FSS for MBAN applications at 2.4GHz is proposed. They are designed using fabric materials suitable for daily clothing. The performance of the antenna is investigated in free space, on a layered biological tissue model, and on a real human body to evaluate SAR. When the antenna is combined with an EBG-FSS structure, isolation between the antenna and the human body is introduced. The results show that the FBR is enhanced by 13 dB, the gain by 6.55dBi, and the SAR is lowered by more than 94%. The CPW antenna demonstrated here is appropriate for future MBAN wearable systems. The design, investigation, and application of water level monitoring utilizing subsurface wireless sensor are covered in this thesis. A wideband double inverted-F antenna is designed and examined to overcome signal attenuation issues. The obtained result is feasible, which has an operating bandwidth of 0.8 to 2.17GHz, with a reflection coefficient better than 10 dB. Moreover, a field trial is conducted to evaluate the robustness of the antenna under extreme conditions. A very good efficiency was also demonstrated, with losses of under 20%. Further, the results from the field experiment established that the antenna is a reliable contender for wireless communication in such challenging environments. / Libyan Ministry of Higher Education / The full text will be available at the end of the embargo: 19th June 2025

Modeling and simulation have become fully ingrained into the set of design and development tools that are broadly used in the field of power electronics. To state simply, they represent the fastest and safest way to study a circuit or system, thus aiding in the research, design, diagnosis, and debugging phases of power converter development. Advances in computing technologies have also enabled the ability to conduct reliability and production yield analyses to ensure that the system performance can meet given requirements despite the presence of inevitable manufacturing variability and variations in the operating conditions. However, the trustworthiness of all the model-based design techniques depends entirely on the accuracy of the simulation models used, which, thus far, has not yet been fully considered. Prior to this research, heuristic safety factors were used to compensate for deviation of real system performance from the predictions made using modeling and simulation. This approach resulted invariably in a more conservative design process. In this research, a modeling and design approach with parametric and model-form uncertainty quantification is formulated to bridge the modeling and simulation accuracy and reliance gaps that have hindered the full exploitation of model-based design techniques. Prior to this research, a few design approaches were developed to account for variability in the design process; these approaches have not shown the capability to be applicable to complex systems. This research, however, demonstrates that the implementation of the proposed modeling approach is able to handle complex power converters and systems. A systematic study for developing a simplified test bed for uncertainty quantification analysis is introduced accordingly. For illustrative purposes, the proposed modeling approach is applied to the switching model of a modular multilevel converter to improve the existing modeling practice and validate the model used in the design of this large-scale power converter. The proposed modeling and design methodology is also extended to design optimization, where a robust multi-objective design and optimization approach with parametric and model form uncertainty quantification is proposed. A sensitivity index is defined accordingly as a quantitative measure of system design robustness, with regards to manufacturing variability and modeling inaccuracies in the design of systems with multiple performance functions. The optimum design solution is realized by exploring the Pareto Front of the enhanced performance space, where the model-form error associated with each design is used to modify the estimated performance measures. The parametric sensitivity of each design point is also considered to discern between cases and help identify the most parametrically-robust of the Pareto-optimal design solutions. To demonstrate the benefits of incorporating uncertainty quantification analysis into the design optimization from a more practical standpoint, a Vienna-type rectifier is used as a case study to compare the theoretical analysis with a comprehensive experimental validation. This research shows that the model-form error and sensitivity of each design point can potentially change the performance space and the resultant Pareto Front. As a result, ignoring these main sources of uncertainty in the design will result in incorrect decision-making and the choice of a design that is not an optimum design solution in practice. / Ph. D. / Modeling and simulation have become fully ingrained into the set of design and development tools that are broadly used in the field of power electronics. To state simply, they represent the fastest and safest way to study a circuit or system, thus aiding in the research, design, diagnosis, and debugging phases of power converter development. Advances in computing technologies have also enabled the ability to conduct reliability and production yield analyses to ensure that the system performance can meet given requirements despite the presence of inevitable manufacturing variability and variations in the operating conditions. However, the trustworthiness of all the model-based design techniques depends entirely on the accuracy of the simulation models used, which has not yet been fully considered. In this research, a modeling and design approach with parametric and model-form uncertainty quantification is formulated to bridge the modeling and simulation accuracy and reliance gaps that have hindered the full exploitation of model-based design techniques. The proposed modeling and design methodology is also extended to design optimization, where a robust multi-objective design and optimization approach with parametric and model-form uncertainty quantification is proposed. A sensitivity index is defined accordingly as a quantitative measure of system design robustness, with regards to manufacturing variability and modeling inaccuracy in the design of systems with multiple performance functions. This research shows that the model-form error and sensitivity of each design point can potentially change the performance space and resultant Pareto Front. As a result, ignoring these main sources of uncertainty in the design will result in incorrect decision making and the choice of a design that is not an optimum design solution in practice.

This research presents a systematic and iterative procedure, as well as theoretical study, on expository sermon construction. The basic approach to sermon design involves the treatment of this subject matter as a design problem, utilizing advanced methodology in engineering design. This includes the modeling technique, the flow-chart method, and the optimization theory. In addition, we use heuristics as the search engine for seeking intelligent and efficient optimum design solutions. The heuristics can best be compared to the "artificial intelligence" or the "wisdom bank," involving six sources of wisdom; these include: talents, gifts, creativity, knowledge, experience and spiritual insights. The results represented in this thesis are believed to have demonstrated original findings in the following areas. First, the subject matter is found to be of a design nature, sharing the common characteristics of a general class of the design discipline, namely, having a 3-stage iterative procedure of the ABA' model. Secondly, a mathematical as well as physical model of the sermon design problem is developed in this study, using both homiletic and hermeneutic principles. The human body is used as the physical model, making it possible for simple visualization of the sermon structure and for performance evaluation. A mathematical model is found to be the "Heuristic Combinatorial Optimization Problem" and consists of eight design variables. Although it is not yet possible to develop a computer-aided protocol to seek solutions, an alternative approach called the "Web-Chart Method" can potentially be adaptable to an interactive computer system in the future. It serves as a two-dimensional "design chart" on paper, in which iterative procedures can be performed manually. The advantage is that the designer can direct his or her heuristic search for optimum solutions with the help of a number of design tools, including the "Insight-Recording Sheet" and the "Analogical Analysis Chart." With these tools, the designer has, at his or her disposal, the ability to search for solutions in sermon design, while still maintaining a global view with all the design variables controlled for. In this research, the principles of combinatorial heuristics applicable to the field of optimum design of expository sermons have been described. They are based on heuristic combinatorial optimization methods in the engineering design field with refinements geared to the homiletic as well as hermeneutic nature of the problem. The approaches represented here would allow a designer to utilize resources that are not otherwise available and/or are not easily manageable. With these research results, one would be able to design sermons innovatively and optimally in a systematic and heuristic-guided manner. Further extension of this work would lead to a new field of research and development in the computer-aided design of expository sermons. Key words: preaching; homiletics; expository preaching; design for preaching; sermon construction; computer-aided sermon design; sermon design optimization; heuristic sermon design; heuristic sermon optimization; heuristic combinatorial optimization. / Practical Theology / D. Th.(Practical Theology)

In this work, the data analysis of oscillating flapping fins is conducted for mathematical model. Data points of heave and surge force obtained by the CFD (Computational Fluid Dynamics) for different geometrical kinds of flapping fins. The fin undergoes a combination of vertical and angular oscillatory motion, while travelling at constant forward speed. The surge thrust and heave lift are generated by the combined motion of the flapping fins, especially due to the carrier vehicle’s heave and pitch motion will be investigated to acquire system identification with CFD data available while the fin pitching motion is selected as a function of fin vertical motion and it is imposed by an external mechanism. The data series applied to model unsteady lifting flow around the system will be employed to develop an optimization algorithm to establish an approximation transfer function model for heave force and obtain a predicting black box system with nonlinear theory for surge force with fin motion control synthesis.