Doctoral Dissertations (FEAS)

Permanent URI for this collectionhttps://hdl.handle.net/10155/401

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Access control obligation specification and enforcement using behavior pattern language
(2018-01-01) Sharghigoorabi, Mohammadhassan; Liscano, Ramiro
Increasing the use of Internet-based devices offers novel opportunities for users to access and share resources anywhere and anytime so that such a collaborative environment complicates the design of an accountable resource access control system. Relying on only predefined access control policies based on an entity's attributes, as in traditional access control solutions, cannot provide enough flexibility to apply continuous adjustments in order to adapt to any kind of operative run time conditions. The limited scope and precision of the existing policy-based access control solutions have put considerable limitations on adequately satisfying the challenging security aspects of the IT enterprises. In this research, we focus on the obligatory behavior that can play an important role in access control to protect resources and services of a typical system. Since traditional access control is performed only once before the resource is accessed by the subject, the access control system is unable to control the fulfillment of obligation while the access is in progress. Practically, such a requirement is implemented in hard-coded and proprietary ways. Consequently, the lack of sophisticated means for specification and enforcement of obligation in access control system decreases its flexibility and may also lead to the security breach in sensitive environments. We provide a descriptive language that is capable of defining a variety of complex behavior patterns based on a sequence of user actions. Such a description can be used to specify different elements of the obligation in order to attach to a policy language, and it is also used to generate queries for behavior matching purposes. Moreover, we propose a behavior pattern matching framework to approve the fulfillment of the obligation by looking into the audit logs. However, this method is extremely inadequate for ongoing obligations. Therefore, we proposed a compliance engine by utilizing complex event processing in order to make a decision to revoke or continue the access in a timely manner. We implemented both frameworks that can be used to approve the obligation fulfillment as well as to evaluate the expressive power and complexity of our proposed language.
Additive manufactured biodegradable and biocompatible polymeric nanocomposite scaffolds for bone tissue engineering applications
(2021-08-01) Karimipour Fard, Pedram; Rizvi, Ghaus; Pop-Iliev, Remon
In this thesis, the focus is on using the fused deposition modeling (FDM) method to manufacture functional biodegradable nanocomposite Polymeric Bone Tissue Scaffolds (PBTS). PBTSs are complex products, which have attracted significant attention in the literature in recent decades. In this study, a commercial and user-friendly FDM manufacturing technique was used to fabricate Polycaprolactone (PCL)/Nano-Hydroxyapatite (nHA)/Chitin-Nano-Whisker (CNW) nanocomposite scaffolds with advanced geometrical designs. The fabricated scaffolds were developed to have functional mechanical, biological, and biodegradation properties. Multiple stages of experimental, numerical, and analytical analyses were performed to achieve these goals. The scaffolds were manufactured in Triply Periodic Minimal Surfaces (TPMS) designs. The impacts of the advanced biomimetic designs, porosity, and biodegradation on the mechanical and morphological properties of the scaffolds were investigated. The nanocomposite filaments for the FDM method were produced using green manufacturing methods. The manufactured novel FDM filaments were characterized using Thermo-Gravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR) to ensure the precision of the nanocomposite contents. The FDM processing conditions of the novel nanocomposite filaments were optimized using Taguchi’s orthogonal array experimental design method to achieve the optimal mechanical properties and structural integrity. The 3D printed nanocomposite bone tissue scaffolds were characterized to assess their mechanical and biological properties. The biodegradation rates of the 3D printed Gyroid-designed nanocomposite PBTSs were estimated in sixty weeks of biodegradation, employing numerical, and experimental results. Machine learning methods were used to connect the independent experimental and numerical results and extract objective functions to model properties of the 3D printed nanocomposite PBTSs. Multi-objective optimization was performed to propose non-dominated optimal options for the PBTSs porosity and the nanocomposite fillers percentages. The results indicated that the proposed green manufacturing method successfully fabricated the nanocomposite FDM filaments with high precision. The FDM printed PCL/nHA/CNW nanocomposite PBTSs with Gyroid structure have high mechanical properties in the practical range of bone tissue scaffolds, enhance cell proliferation and attachment to the scaffolds and biodegrade in the practical period for PBTSs. The multi-objective optimization method presents a few significant non-dominated optimal options, which can be selected based on the consumer’s priorities.
Addressing electrode-specific degradation in the production and performance of electrochemical energy storage systems
(2023-08-01) Khosravinia, Kavian; Kiani, AmirKianoosh; Lin, Xianke
This thesis addresses the pressing issue of sustainable development and climate change by examining the life cycle (degradation) of electrochemical energy storage devices. Specifically, it investigates a green synthesis technique for high-performance pseudocapacitor electrodes and uses machine learning algorithms to predict and prevent degradation mechanisms in lithium-ion batteries. The research demonstrates the effectiveness of the laser irradiation technique, called ultra-short laser pulses for in situ nanostructure generation (ULPING) for fabricating a metal oxide layer on a titanium sheet under ambient conditions, as well as the potential of machine learning algorithms as a tool for constructing mathematical models to forecast the electrochemical behavior of pseudocapacitors. The thesis also highlights the importance of utilizing data-driven approaches in electrode design procedures and promoting sustainable habits in all aspects of life. In addition, the study provides insight into the modeling and prediction of the electrochemical behavior performance of pseudocapacitors, which could facilitate the development of optimal electrodes. Moreover, the research examines one of the most detrimental degradation mechanisms that occur during the fast-charging process, known as the deposition of metallic lithium or lithium plating, in lithium-ion batteries. The proposed machine learning approach based on ensemble selection accurately predicts the anode potential under various charging conditions and achieves high accuracy in preventing lithium plating. Overall, this research offers promising methods for employing ultra-short laser pulses for in situ nanostructure generation to fabricate nanostructures on transition metals that have the potential to be used in pseudocapacitor electrodes and highlights the importance of utilizing machine learning techniques in predicting and preventing degradation mechanisms in electrochemical energy storage devices.
An advanced electrospinning method of fabricating nanofibrous patterned architectures with controlled deposition and desired alignment
(2015-11-18) Rasel, Sheikh Md; Rizvi, Ghaus
We introduce a versatile advanced method of electrospinning for fabricating various kinds of nanofibrous patterns along with desired alignment, controlled amount of deposition and locally variable density into the architectures. In this method, we employed multiple electrodes whose potentials have been altered in milliseconds with the help of microprocessor based control system. Therefore, key success of this method was that the electrical field as well as charge carrying fibers could be switched shortly from one electrode’s location to another, as a result, electrospun fibers could be deposited on the designated areas with desired alignment. A wide range of nanofibrous patterned architectures were constructed using proper arrangement of multiple electrodes. By controlling the concurrent activation time of two adjacent electrodes, we demonstrated that amount of fibers going into the pattern can be adjusted and desired alignment in electrospun fibers can be obtained. We also revealed that the deposition density of electrospun fibers in different areas of patterned architectures can be varied. We showed that by controlling the deposition time between two adjacent electrodes, a number of functionally graded patterns can be generated with uniaxial alignment. We also demonstrated that this handy method was capable of producing random, aligned, and multidirectional nanofibrous mats by engaging a number of electrodes and switching them in desired patterns. A comprehensive study using finite element method was carried out to understand the effects of electrical field. Simulation results revealed that electrical field strength alters shortly based on electrode control switch patterns. Nanofibrous polyvinyl alcohol (PVA) scaffolds and its composite reinforced with wollastonite and wood flour were fabricated using rotating drum electrospinning technique. Morphological, mechanical, and thermal, properties were characterized on PVA/wollastonite and PVA/wood flour nanocomposites containing 0, 5, 10, and 20 wt % of fillers. Morphological analyses carried out by digital optical microscope, scanning electron microscopy, x-ray computed tomography, and Fourier transform infrared spectroscopy, confirmed the presence and well dispersion of fillers in the composites. In addition, improvement of mechanical properties with increased filler content further emphasized the adhesion between matrix and reinforcement. PVA with 20 wt % wollastonite composite exhibited the highest tensile strength (11.99 MPa) and tensile module (198 MPa) as compared to pure PVA (3.92 MPa and 83 MPa, respectively). Moreover, the thermal tests demonstrated that there is no major deviation in the thermal stability due to the addition of wollastonite in PVA scaffolds. Almost similar trend was observed in PVA/wood flour nanocomposites where tensile strength improved by 228 % for 20 wt % of reinforcement. The PVA/wollastonite and PVA/wood flour fibrous nanocomposite which poses higher mechanical properties might be potentially suitable for many advanced applications such as filtration, tissue engineering, and food processing. We believe, this study will contribute to further scientific understanding of the patterning mechanism of electrospun nanofibers and to allow for variety of design of specific patterned nanofibrous architectures with desired functional properties. Therefore, this improved scheme of electrospinning can have significant impact in a broad range of applications including tissue engineering scaffolds, filtrations, and nanoelectronics.
Advances in parallel robotics for flexible and reconfigurable manufacturing
(2014-04-01) Coppola, Gianmarc; Zhang, Dan; Liu, Kefu
Parallel robotic manipulators are a specific type of robot that has multiple limbs which are ultimately connected to a moving body. Within this regime, there are several sub-classes of robots characterized by certain inherent traits. Common to all sub-classes is the ability to articulate the moving platform by actuating each of the limbs. In general, it has been shown that these types of robotic manipulators possess several types of advantageous properties. Some of these properties are: good dynamic character, high stiffness, high precision, large payload to weight ratio, and high speed. Flexible and reconfigurable manufacturing regimes are new manufacturing system paradigms that aim at achieving cost-effective and rapid system changes. Essentially, a system classified as flexible or reconfigurable would be one that is adaptive to change in the market without the need to re-design or re-develop its components. The advantage of such a system is in theory very large. To date, there has been some enhancements made in the area, however there are still many open aims and possible improvements to be investigated. Much of which aims at furthering the concepts from theory to practical applications. The main objective of this dissertation is to enhance the knowledge base in flexible and reconfigurable systems through parallel robotics. Specifically, by utilizing new ideas in parallel robotics tailored to these manufacturing regimes, significant improvements in the knowledge base are attained. These can be classified under one specific regime of parallel robotics and further categorized as passive, semi-active, and active (adaptive). This thesis first focuses on a new design methodology related to flexible and reconfigurable manufacturing. Essentially, the method proposes a systematic approach to recon figure the dynamic properties of robotic devices for various functional requirements that would be part of a flexible manufacturing situation. The method is tested on an example structure and results indicate that the proposed reconfiguration method outperforms existing devices. Next, this dissertation focuses on the design of new robotic architectures that are more adaptive. Specifically, the goal is to achieve structures that can be adaptive in real-time. Existing structures are only reconfigurable passively and need to stop operation in order to reconfigure manually. To this end, a hybrid structure that is semi-active reconfigurable is first investigated. It is dubbed the ReSl-Bot. A complete engineering analysis and design is conducted illustrating its properties. To take this one step further, a novel class of hybrid adaptive parallel robots is then proposed. A 6-DOF robot belonging to this class called the HAPM mk.1 is studied in detail. It is effectively shown that this novel design has the ability to adapt properties actively. This type of adaption could be used for the performance enhancement in many applications, particularly for flexible manufacturing. Properties such as DOF, stiffness, dexterity, precision, kinetics, energy consumption, backlash, etc. could potentially be altered for varying applications and requirements. Notably, a complete theoretical analysis is conducted, ending with analytical dynamics and control.
An AFE based embedded system for physiological computing
(2019-11-01) Khan, Md. Nazrul Islam; Eklund, Mikael
The present hospital-based health care system will be burdened because of the growing aging population. Aging and stress result in cardiovascular diseases that cost around seventeen million lives globally every year. To control cardiovascular ailments, at-home monitoring of blood pressure is very important which helps diet control and promote medication adherence. The present health monitors are by default bulky, daunting, invasive, and not suitable for home use. The de-facto architecture of such systems entails discrete sensors and analog sub-systems known as the analog front end (AFE) for biosignal acquisition, conditioning, and vital bridging function. Being discrete and analog, signal processing is limited. Besides, with large form factor, component counts and power consumption increase with the constant need for calibration. For more than one century, the non‐invasive measurement of blood pressure has relied on the inflation of pneumatic cuffs around a limb. In addition to being occlusive and thus cumbersome, clinical cuff‐based methods, provide intermittent BP readings, hence impeding the suitable monitoring of short‐term BP regulation mechanisms. Cuff‐based methods may not be a true representative of BP. Therefore, the development of novel technologies that eliminate the use of pneumatic cuffs is justified. In this thesis, I present a highly integrated programmable AFE based biosignal computing platform, named TasDiag. TasDiag is a novel, integrated, remote platform capable of multimodal biosignal computing including non-invasive, continuous, and cuff-less BP estimation based on pulse transit time. Being integrated, and digital, TasDiag is a single board solution with an auto calibration scheme implemented through novel signal processing and computing. The developed system is validated using real-time data from human subjects and subjected to various statistical analyses for performance and accuracy. Test results show TasDiag comply with the Association for Advancement for Medical Instrumentation standard and can replace its industry-standard counterparts.
An investigation of ultraviolet and ionizing radiation on the eye-lens of rainbow trout
(2024-06-01) Kocemba, Marta; Waller, Edward; Waker, Anthony
The lens of the eye is one of the most radiosensitive tissues in the body, and the effects of radiation on the eye-lens are not fully understood. Dose limit and tissue effect threshold recommendations have been lowered due to cataracts occurring at unexpected doses, and there is therefore a need for biological experiments on the early stages of cataractogenesis. There is also a need for radiobiological evidence in the context of environmental radioprotection, since the current recommendations for dose limits to non-human biota are based on assumptions rather than evidence of radiation response. In this work, the effects of ionizing and ultraviolet radiation on the eye-lens of rainbow trout have been investigated in vitro. Eye-lenses were excised and maintained in culture, then irradiated with either X-rays or ultraviolet (UV) radiation and assessed for several types of damage response. Optical quality was quantified using laser focal analysis; the structural integrity of cell membranes was assessed by measuring protein leakage from eye-lenses; and the response of lens cells to the radiation was characterized using proteomics analysis. A dose of 0.2 J/cm² of UVB radiation was shown to produce no changes in the optical quality of intact rainbow trout eye-lenses over 30 days post-irradiation. However, there is evidence of a damage-response process that triggers cellular 'housekeeping' and results in irradiated lenses maintaining transparency longer than control lenses. Comparative studies with groups of lenses being exposed to either 1 J/cm² of UVB radiation or 2 Gy of X-rays has shown that this dose of ionizing radiation produces significant changes in the expression of proteins related to cell membranes, DNA repair, and removal of damaged proteins. The UVB dose led to elevated expression of the same types of proteins, but not in significant amounts. Combining results across damage assays and experiments has revealed trends which support the concepts of individual variation in radiosensitivity, membrane damage and bystander effect as factors in early cataractogenesis, and the relationship between stress response and lens transparency. Overall, this characterization of specific aspects of damage response in the eye-lens to ionizing and ultraviolet radiation has contributed to the understanding of cataractogenesis as well as environmental radioprotection.
Analysis and design of computationally efficient modulation schemes for Three Phase Three Switch rectifier for transportation electrification
(2018-02-01) Channegowda, Janamejaya; Williamson, Sheldon
It is a well-known fact that the transportation sector emits a large amount of pollutants to the atmosphere. The growing need for reducing the carbon footprint has led to sincere efforts being made in the direction of electrification of commercial vehicles, which conventionally run on by-products of crude oil. The Canadian government is currently aiming at reducing greenhouse emissions by 30% below the early 2000s levels by the year 2030. This goal has led to major auto manufacturers releasing their respective models of battery-powered electric vehicles (EVs) completely compliant with the SAE J1772 standards. However, the commercial success of EVs heavily relies on the presence of high-efficiency charging stations. This thesis reviews presently available, Level 3/DC fast charging systems, followed by a brief description and evaluation of DC fast-charging infrastructure. Different power converter topologies and viable configurations are presented, compared, and evaluated, based on the power level requirements, efficiency of the topology, cost, and technical specifications. In this thesis the possibility of employing the Three Phase Three Switch (TPTS) converter as a single-stage charger for DC fast charging of electric vehicles is explored. Control of contemporary three phase power converters, employed in charging infrastructures, is achieved by Space Vector (SV) based modulation schemes. This thesis proposes a novel modulation technique for TPTS rectifier. The general SV modulation scheme xxvii xxviii used to control the TPTS is reviewed in this thesis. Numerous switching combinations possible for different positions of the Zero and Active vectors are derived. Based on the positions of these vectors in different sectors of the SV diagram, several switching sequences are presented. The switching combinations are analyzed to obtain three modulating waves. The new carrier-based modulation scheme for TPTS is implemented and validated using software simulation. This new scheme is easier to implement compared to the traditional SV based modulation technique due to reduced number of mathematical computations. A 1 kW hardware prototype was built to validate the proposed modulation scheme. This thesis provides a detailed description about arriving at the proposed modulation scheme for TPTS from traditional SV modulation scheme. The implementation of the converter and its performance analysis is reported in this thesis
Analysis and evaluation of transactive energy control in active distribution systems
(2016-10-01) Gray, Matt; Ibrahim, Walid Morsi
The electric power distribution system is experiencing significant operational changes due to the integration of plug-in electric vehicles and intermittent distributed energy resources such as rooftop solar photovoltaics. As plug-in electric vehicle charging represents a significant increase in system loading, both distribution transformers and substation transformers are subject to overload conditions which rapidly degrade transformers lifetime. Furthermore, the increased penetration of rooftop solar photovoltaic in the residential sector may lead to bi-directional power flow and may additionally cause overload to the distribution transformers. In order to accommodate the growing market penetration of plug-in electric vehicles and rooftop solar photovoltaics, the electric utility must employ energy management to prolong the transformers lifetime. Given that transformers represent one of the most expensive assets in the distribution system, failure to resolve transformer lifetime degradation issues require the electric utility to incur the costs of transformer replacement or upgrading. The work in this dissertation proposes a transactive energy control methodology to perform residential energy storage system control as a means of reducing transformer lifetime degradation. The results have shown that the proposed framework may extend median annual distribution transformer lifetime by nearly double the expected lifetime of distribution transformers without transactive energy control. Finally, the proposed transactive control scheme has also been found to reduce active power losses within the system.
Analysis and mitigation of the impacts of integrating fast-charging stations on the voltage fluctuations
(2020-10-01) Alshareef, Sami; Ibrahim, Walid Morsi
As the number of electric vehicles increases, fast charging becomes a necessity in the electric service stations; not only to reduce the charging and waiting times for electric vehicles whether in service or in a queue, but also to increase their commercial benefits by increasing their utilization rates. Fast charging stations are characterized by their high-power consumption from the electric grids to fulfill these aforementioned aims. Times and periods of that consumption are indeterminate due to several uncertain parameters that are inherent in the electric vehicles charging process, such as their numbers, their battery capacities, their state-of-charge levels at time of arrivals, and their time of arrivals, which may all lead to a degradation in the quality of electric power delivered to the customers. The research presented in this thesis focuses on the impacts of fast charging stations on three power quality phenomena, namely voltage magnitude variations, voltage unbalance, and voltage fluctuation. The Markov Chain Monte Carlo is proposed to estimate the required energy from each fast charging station when it is utilized to charge the electric vehicles, considering their stochastic parameters. Two charging methods are implemented in this work: charging with an estimated output power and charging with an actual output power. The results reveal that the impact of fast charging stations on voltage fluctuation by either of these charging methods can lead to light flicker. When the estimated output power is utilized, the light flicker is higher compared to when the actual output power is utilized. When the operation of Fast Charging Stations causes a voltage fluctuation and light flicker, the FCSs may get disconnected which results in a financial loses represented by the FCS downtime. The FCS downtime can be avoided by mitigating the voltage fluctuation and light flicker. Several flicker mitigation devices are analyzed and compared based on different criteria. The comparison reveals that distribution static compensators considers the cheapest mitigation device, according to the cost per kVAr basis and the total annual equivalent cost. Besides, to mitigate the impact on the voltage and light flicker, a novel smart charging is proposed in this study in which customers can select one of three charging services available in the fast chargers: premium, regular, or economic charging power. The charging power is selected upon customer priority toward the time and cost which offers less control than those currently available in the literature. The proposed smart charging preserves the balance of customer's value of time and value of cost. The proposed smart charging achieves a tremendous reduction in the cost of mitigation the voltage fluctuation and light flicker. Annual cost of the proposed smart charging is less than the annual cost of distribution static compensators by a minimum of 90% to a maximum of 99 %. The proposed smart charging offers a compromise solution to satisfy several stakeholders with different interests. Thus, equipment of system’s operator, investor of fast charging station, nearby customers, and owners of electric vehicles will not be impacted by integrating the fast charging station.
Analysis of net zero energy buildings and communities that strategically integrate transportation energy
(2024-05-01) Garmsiri, Shahryar; Rosen, Marc A.
The limited oil supplies, rising fuel prices and greenhouse gas (GHG) emissions, have heightened the demand for alternative energy sources, especially in transportation and residential sectors. The rise of electric vehicles (EVs), plug-in hybrid vehicles (PHEVs), and fuel cell vehicles (FCVs) have reduced dependence on oil and emissions. Governments and researchers are exploring net zero energy building/community (NZEB/C) options to meet GHG emission mandates for new and existing dwellings. This study evaluates the benefits of integrating transportation energy with a NZEB via the electric grid, focusing on EVs, PHEVs, and FCVs. The study analyzes energy performance in a NZEB/C and transportation sector, aiming to achieve net zero energy status in both new and existing communities. The motivation of this study is to address the limited research on EV, PHEV integration with NZEBs, particularly on larger NZEB/Cs and FCV side. A methodology was developed to analyze communities with various vehicles simultaneously, addressing issues with software programs lacking databases for alternative fuels. MATLAB was used for simultaneous energy analysis and transportation integration, reducing computational time and eliminating the need for multiple programs. This analysis, unrestricted to specific software programs, fills the gap in analyzing integration of transportation energy within a NZEB/C for potential benefits. A 1-D thermal resistance network was developed, enabling faster energy usage calculations and better understanding of energy flow within a house/building. The study revealed, discharge of energy from EV battery, PHEV and FCV energy contributions via their hydrogen and biogas fuel tanks accounted for 10%, 16%, and 25%, respectively, of the community's energy consumption. As the communities considered are expanded to larger sizes, energy discharge and contribution decreases due to vehicle storage limitations and the increased presence of smaller vehicles in the analysis. The PHEV converted to operate on biogas is an attractive type of vehicle for transportation energy integration due to its lower cost compared to gasoline and diesel fuels. However, it is less environmentally friendly compared to EVs and FCVs due to the emission produced using biogas. The FCV's economic benefits determined to be achieved when the cost of hydrogen fuel was less than 4.95 CAD/kg.
Analysis of the thermal hydraulics of a multiphase oxygen production reactor in the Cu-Cl cycle
(2016-06-01) Abdulrahman, Mohammed W.; Agelin-Chaab, Martin; Wang, Zhaolin
In the thermochemical water splitting process by Cu-Cl cycle, oxygen gas is produced by an endothermic thermolysis process in a three-phase reactor. In this thesis, the required heat for the thermolysis process is provided by adopting the idea of heating some of the stoichiometric oxygen gas by using a nuclear reactor heat source. Then, the gas is re-injected into the reactor from the bottom, to transfer heat directly to the slurry bed of molten salt and solid reactant. In this thesis, the thermal hydraulics of the oxygen slurry bubble column reactor (SBCR) is investigated experimentally and numerically. In the experiments, lower temperature alternative materials, such as helium gas at 90°C and water at 22°C, are used to mimic the actual materials of the oxygen gas at 600°C and molten CuCl at 530°C. From the experimental studies, new forms of empirical equations are formulated for the overall gas holdup and the volumetric heat transfer coefficient in terms of the design and input parameters of the SBCR, such as; the superficial gas velocity, reactor height, and solid particles concentration. The empirical equations are obtained for both bubbly and churn-turbulent flow regimes. It is also determined experimentally the flow regime transition point between bubbly and churn-turbulent flow regimes. Furthermore, it is found experimentally that the solid particle diameter has insignificant effect on the overall gas holdup. To better understand the thermal hydraulics of the oxygen SBCR, a computational fluid dynamics (CFD) models are developed by using the ANSYS FLUENT software. All CFD simulation results are validated by the experimental results of the alternative materials system with good agreements. From the CFD simulations, it is also found that the gas temperature decreases dramatically near the bottom of the reactor, and the effects of the superficial gas velocity, reactor height, and solid concentration on the gas temperature are negligible. Finally, a simple correlation is obtained to calculate the number of oxygen reactors in terms of the superficial gas velocity of the oxygen gas and the oxygen production rate.
Analysis, assessment and optimization of biomass mixed heavy-oil driven integrated gasification combined cycle for multigeneration
(2017-11-01) Islam, Shahid; Dincer, Ibrahim
There has been increasing interest in employing Integrated Gasification Combined Cycles (IGCC) using various biomasses and low-rank coals for producing multiple outputs. The most of the existing IGCC plants do not conserve the low-grade heat, use air separation unit and the presence of coal produces high amount of carbon based emissions. The production of syngas through gasification of renewable feedstocks, such as biomass, organic food waste and animal manure is an attractive option with less emissions. In this thesis, three novel multigeneration IGCC based on organic and refinery wastes are specifically developed for three sectors; community, food industry and refinery. The systems are simulated using Aspen (Plus) and results are validated through energy and exergy analyses, and research reported in the literature. The exergy analysis is performed with the help of Engineering Equation Solver (EES). The developed systems can be employed anywhere in the world with some modifications, however, the case studies are performed for Saudi Arabia for assessment. The Genetic Algorithm model is used to optimize the developed systems. A multi-objective optimization approach is applied to achieve the best performances of the developed systems. Three objectives function used in this study include; exergy efficiency, total cost and CO2 emissions. The developed systems are environmentally benign as the production of CO2 is low enough to meet the stringent environmental regulations. The energy and exergy efficiencies of the cold gas, overall, gas turbine and steam turbine for the proposed systems 1 are found to be 58.2% and 57.6%, 55.9% and 32.1%, 29.8% and 26.7%, 34.1% and 60.1%, respectively. The energy and exergy efficiencies of the cold gas, overall, gas turbine and steam turbine for the proposed systems 2 are found to be 62.1% and 61.4%, 57.9% and 33.3%, 29.2% and 25.9%, 33.7% and 61.7%, respectively. The energy and exergy efficiencies of the cold gas, overall, gas turbine and steam turbine for the proposed systems 3 are found to be 68.3% and 68.7%, 60.7% and 34.8%, 27.8% and 24.7%, 34.4% and 60.3%, respectively. The highest magnitude of exergy destruction occurs in combustion chamber. The electrical power output for system 1, system 2, and system 3 is found to be in the order of 461 MW, 433 MW and 466 MW, respectively.
Analysis, assessment and optimization of integrated solar energy systems for multigeneration
(2014-12-01) El-Emam, Rami; Dincer, Ibrahim
The extensive usage of fossil fuel in most of human activities has led to the undesirable effects on the environment starting from global warming and greenhouse effects to the climate changes, acid rain and others. Renewable energy is at the core of most of recent research activities to overcome these environmental challenges. Being an integral part of other renewable resources, solar energy utilization aims to occupy more portion of the world energy framework. Integrated energy systems for multigeneration produces several useful products using the same energy input. Electrical power generation, fresh water, space heating and cooling and domestic hot water are the major commodities that furnish our life activities. Hydrogen is another useful product taken into consideration. The proposed systems in this work cover all these products as a step for achieving a sustainable and environmentally benign community. These systems pose great potential for global warming mitigation. In the work presented, different multigeneration energy systems based on solar energy are introduced. Comprehensive thermodynamic, environmental and economic analyses for the proposed multigeneration energy systems are the main goals of this thesis study. Thermodynamic analyses are based on energy and exergy, associated with the efficiencies of overall and system components performances. For a better understanding of the systems performances and the potential of more improvement in their performances, exergoeconomic and environmental analyses and system optimization are performed. Solar dish based integrated system considering biomass-SOFC as alternative for solar unavailability is the first studied system. The system performance is assessed during solar availability and considering the performance of a 24-hours operation. The second system is based on solar parabolic trough providing concentrated heat to an organic Rankine cycle. The system is integrated with electrolyzer for hydrogen production, a reverse osmosis water desalination unit and absorption chiller system and providing domestic hot water. The third main system is based on heliostat solar system integrated with steam turbine for multigeneration purposes. The system produces cooling, heating, fresh water and hydrogen through electrolysis.
Analytical modeling and simulation of metal cutting forces for engineering alloys
(2012-04-01) Pang, Lei; Kishawy, Hossam A.
In the current research, an analytical chip formation model and the methodology to determine material flow data have been developed. The efforts have been made to address work hardening and thermal softening effects and allow the material to flow continuously through an opened-up deformation zone. Oxley's analysis of machining is extended to the application of various engineering materials. The basic model is extended to the simulation of end milling process and validated by comparing the predictions with experimental data for AISI1045 steel and three other materials (AL-6061, AL7075 and Ti-6Al-4V) from open literatures. The thorough boundary conditions of the velocity field in the primary shear zone are further identified and analyzed. Based on the detailed analysis on the boundary conditions of the velocity and shear strain rate fields, the thick “equidistant parallel-sided” shear zone model was revisited. A more realistic nonlinear shear strain rate distribution has been proposed under the frame of non-equidistant primary shear zone configuration, so that all the boundary conditions can be satisfied. Based on the developed model, inverse analysis in conjugation of genetic algorithm based searching scheme is developed to identify material flow stress data under the condition of metal cutting. ii On the chip-tool interface, The chip-tool interface is assumed to consist of the secondary shear zone and elastic friction zone(i.e. sticking zone and sliding zone). The normal stress distribution over the entire contact length is represented by a power law equation, in which the exponent is determined based on the force and moment equilibrium. The shear stress distribution for the entire contact length is assumed to be independent of the normal stress. The shear stress is assumed to be constant for the plastic contact region and exponentially distributed over the elastic contact region, with the maximum equal to the shear flow stress at the end of sticking zone and zero at the end of total contact. The total contact length is derived as a function governed by the shape of normal stress distribution. The length of the sticking zone is determined as the distance from the cutting edge to the location where the local coefficient of friction reaches a critical value that initiates the bulk yield of the chip. Considering the shape of the secondary shear zone, the length of the sticking zone can also be determined by angle relations. The maximum thickness of the secondary shear zone is determined by the equality of the sticking lengths calculated by two means. With an arbitrary input of the sliding friction coefficient, various processing parameters as well as contact stress distributions during orthogonal metal cutting can be obtained.
Assessing district energy systems performance integrated with multiple thermal energy storages.
(2013-08-01) Rezaie, Behnaz; Rosen, Marc A.
The goal of this study is to examine various energy resources in district energy (DE) systems and then DE system performance development by means of multiple thermal energy storages (TES) application. This study sheds light on areas not yet investigated precisely in detail. Throughout the research, major components of the heat plant, energy suppliers of the DE systems, and TES characteristics are separately examined; integration of various configurations of the multiple TESs in the DE system is then analysed. In the first part of the study, various sources of energy are compared, in a consistent manner, financially and environmentally. The TES performance is then assessed from various aspects. Then, TES(s) and DE systems with several sources of energy are integrated, and are investigated as a heat process centre. The most efficient configurations of the multiple TESs integrated with the DE system are investigated. Some of the findings of this study are applied on an actual DE system. The outcomes of this study provide insight for researchers and engineers who work in this field, as well as policy makers and project managers who are decision-makers. The accomplishments of the study are original developments TESs and DE systems. As an original development the Enviro-Economic Function, to balance the economic and environmental aspects of energy resources technologies in DE systems, is developed; various configurations of multiple TESs, including series, parallel, and general grid, are developed. The developed related functions are discharge temperature and energy of the TES, and energy and exergy efficiencies of the TES. The TES charging and discharging behavior of TES instantaneously is also investigated to obtain the charging temperature, the maximum charging temperature, the charging energy flow, maximum heat flow capacity, the discharging temperature, the minimum charging temperature, the discharging energy flow, the maximum heat flow capacity, and performance cycle time functions of the TES. Expanding to analysis of one TES integrated with the DE system, characteristics of various configurations of TES integrated with DE systems are obtained as functions of known properties, energy and exergy balances of the DE system including the TES(s); and energy and exergy efficiencies of the DE system. iv The energy, exergy, economic, and CO2 emissions of various energy options for the DE system are investigated in a consistent manner. Different sources of energy considered include natural gas, solar energy, ground source heat pump (GSHP), and municipal solid waste. The economic and environmental aspects and prioritization, and the advantages of each technology are reported. A community-based DE system is considered as a case study. For the considered case study, various existing sizing methods are applied, and then compared. The energy sources are natural gas, solar thermal, geothermal, and solid waste. The technologies are sized for each energy option, then the CO2 emissions and economic characteristics of each technology are analysed. The parallel configuration of the TESs delivers more energy to the DE system compared with other configurations, when the stored energy is the same. With increasing the number of parallel TESs results in a higher energy supply to the DE system. The efficiency of the set of the TESs is also improved by increasing the number of parallel TESs. The tax policy, including the tax benefits and carbon tax, is a strong tool which will influence the overall cost of the energy supplier’s technology for the DE systems.The Enviro-Economic Function for the TESs is proposed and is integrated with the DE system, which suggests that the number of TESs required. The energy and exergy analyses are applied to the charging and discharging stages of an actual TES in the Friedrichshafen DE system. For the Friedrichshafen DE system, the performance is analysed based on energy and exergy analyses approach. Furthermore, by using the developed functions in the present study some modifications are suggested for the Friedrichshafen DE system for better performance.
Asynchronous bi-directional relay-assisted communication networks
(2014-02-01) Vahidnia, Reza; Shahbazpanahi, Shahram
We consider an asynchronous bi-directional relay network, consisting of two singleantenna transceivers and multiple single-antenna relays, where the transceiver-relay paths are subject to different relaying and/or propagation delays. Such a network can be viewed as a multipath channel which can cause inter-symbol-interference (ISI) in the signals received by the two transceivers. Hence, we model such a communication scheme as a frequency selective multipath channel which produces ISI at the two transceivers, when the data rates are relatively high. We study both multi- and single-carrier communication schemes in such networks. In a multi-carrier communication scheme, to tackle ISI, the transceivers employ an orthogonal frequency division multiplexing (OFDM) scheme to diagonalize the end-to-end channel. The relays use simple amplify-and-forward relaying, thereby materializing a distributed beamformer. For such a scheme, we propose two different algorithms, based on the max-min fair design approach, to calculate the subcarrier power loading at the transceivers as well as the relay beamforming weights. In a single-carrier communication, assuming a block transmission/reception scheme, block channel equalization is used at the both transceivers to combat the inter-blockinterference (IBI). Assuming a limited total transmit power budget, we minimize the total mean squared error (MSE) of the estimated received signals at the both transceivers by optimally obtaining the transceivers’ powers and the relay beamforming weight vector as well as the block channel equalizers at the two transceivers.
Automated wavelet-based fault detection and diagnosis for smart distribution systems and microgrids
(2017-08-01) Sewilam, Tamer Sayed Abdelhamid Abdelgayed; Ibrahim, Walid M.; Sidhu, Tarlochan
The legacy electric power system is defined as a one-way power flow from a centralized power generation plant to customers (consumers). In the smart distribution systems, the customers are allowed to produce electricity through the distributed energy resources (e.g. solar photovoltaics), as well as to consume energy, hence, the smart distribution systems can be defined as a two-way power flow. The Micro-Grid system is defined as a part of the smart distribution system that may include distributed energy resources, energy storage systems and loads. In addition, the Micro-Grid system can operate in two modes, grid-connected or non-grid-connected (i.e., islanded mode). The protection of the Micro-Grid system represents one of the major operational challenges, in particular when considering the integration of distributed energy resources, which may result in different fault current levels, especially in islanding mode. However, the capability of protection system equipment to be more accurate and dependable for faults diagnostic in the Micro-Grid is considered a challenge until now. In this thesis, an automated wavelet-based fault detection and diagnosis technique based on a combination of Wavelet Transform, Harmony Search Algorithm, and Machine Learning approaches is developed for fault diagnosing in the Micro-Grid systems. The harmony search algorithm as an optimization technique is used to identify the optimum wavelet function(s) and the optimum wavelet decomposition level(s) to extract the most prominent features that are hidden in the current/voltage waveforms when applying the discrete wavelet transform. This is unlike previous works in which only one arbitrary wavelet function is used based on a trial and error process. In order to automate the fault classification process in Micro-Grid system, and to examine the effectiveness of the automated wavelet-based fault detection and diagnosis method against iii other approaches, two machine learning techniques (i.e. Decision Tree as an eager learner, and KNearest Neighbor as a lazy learner) are used. The performance of the two classifiers is estimated using the Monte Carlo stratified cross validation method. The Consortium for Electric Reliability Technology Solutions Micro-Grid is used as a test-bed system after modelling in Power Systems Computer Aided Design/Electromagnetic Transient Direct Current software package. The study also takes into consideration different operating modes, different fault types, different fault resistances, and also different fault locations. The results of implementing the proposed automated wavelet-based fault detection and diagnosis technique shows a significant improvement in the classification accuracy compared to other previous approaches reaching an overall accuracy of 95.63% in the Micro-Grid test-bed system. In addition, the proposed technique has been verified experimentally, and the results of the experimental set-up confirmed the validity/effectiveness of the proposed approach in real-time implementation.
Automatic trajectory generation for mobile-manipulators using 3D LiDAR scans of unknown surfaces
(2019-07-01) Wrock, Michael; Nokleby, Scott
An approach to improving worker safety in underground uranium drift mining through automating the radiation scanning and shotcrete application process is presented. Utilizing the Robot Operating System (ROS) framework to achieve autonomous operation, workers can be removed from the most hazardous areas of the mine. Worker knowledge and experience is utilized when instructing the system from a remote location. The current approach to radiation scanning exposes the workers to radiation hazards and employs the use of cumbersome handheld radiation sensors that are difficult to position accurately. Sprayable concrete liner known as shotcrete is applied to all surfaces of the drift to protect workers from hazards, such as rock fall and radon gas. Proper application of shotcrete and visual estimation of its thickness require highly skilled operators. This research presents a trajectory generation algorithm that is capable of autonomously applying shotcrete to unknown surface geometries. The trajectory generation algorithm can also be used to perform radiation scanning with the use of a previously developed tool changer. A novel localization algorithm developed for use in underground mining uses the Point Cloud Library (PCL) to accurately register point cloud scans of the drift from before and after shotcrete application and produces thickness estimates of the entire shotcrete area. Estimating shotcrete thickness allows for verification to ensure worker safety and eliminates the human error present in current thickness estimation methods. The hardware and software systems are highly modular in order to allow components or algorithms to easily be replaced or implemented on other systems. The localization system presented uses fiducial markers that allow the robot to generate 3D point cloud representations of the entire mine. While scanning the drift face, a shielded radiation sensor can be used for more directional measurements, and the locations at which the measurements are taken relative to the drift face can be recorded with great accuracy. Verifying shotcrete thickness, mapping mine drifts, and protecting workers from hazardous environments are three factors which contribute to improved safety and monitoring of underground uranium mines.
Autonomous driving control strategies for multi-trailer articulated heavy vehicles with active safety system
(2023-05-01) Rahimi, Amir; He, Yuping
This study aims to develop automated driving strategies and integrated active control system for multi-trailer articulated heavy vehicles (MTAHVs) to enhance road transport efficiency, directional performance, and safety. To this end, a MTAHV with the configuration of A-train double was selected to be the subject vehicle, and the required vehicle models were generated. The corresponding nonlinear TruckSim model was employed as the virtual for co-simulations. The original contributions of the thesis in autonomous driving control of MTAHVs include: 1) a lateral preview driver model for MTAHVs was developed using the optimal preview control method; 2) a longitudinal motion-planning and control strategy using fuzzy sets was also devised; 3) an integrated control system was designed for coordinating autonomous driving and active trailer and dolly steering (ATDS) using a model predictive control (MPC) technique; and 4) a model-based predictive motion planning method was developed using the Frenet-Serret frame. The proposed lateral preview driver model may operate in two modes according to varied forward speed: i) in high-speed operations, the lateral stability is prioritized, and the high-speed and stability-oriented mode is activated; ii) while in low-speed curved path negotiations, the path-following off-tracking performance is emphasized, and the low-speed path-following mode is activated. It also takes benefits of the vehicle units’ body-fixed reference frames for lateral deviation calculations to mimic the driver’s local perception of vehicle position and reference path. If the so-called driver neuromuscular delay is set to zero, the driver model may perform as an autonomous human-like controller for vehicle lateral motion control. The devised longitudinal motion planner considers the road curvature over a preview horizon to regulate vehicle forward speed. It is featured with the predictive and compensatory throttle/brake actuations to assure all the vehicle units’ lateral stability. The MPC-based control method integrates the ATDS into the automated tractor steering and speed control, while the ATDS is activated to operate in either high-speed or low-speed mode, thereby improving the directional performance. The developed trajectory planner benefits from a model-based predictive approach to customize the generated trajectory to enhance the lateral stability in high-speed evasive maneuvers. The innovative findings of this dissertation will contribute to the advancement and development of autonomous driving control for MTAHVs.

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