Engineering Commons^™

Finite Element Analysis Simulations Of Micro And Nano-Electromechanical Sensors For Design Optimization, Nicholas Frank Deroller

Theses and Dissertations

Micro and Nano-electromechanical sensors (MEMS and NEMS) provide a means of actively sensing minute changes in the surrounding environment. Small changes in temperature, momentum, and strain may be sensed in passive modes while greater sensing possibilities exist in active modes. Theoretical femto-gram resolution mass detection and heated element sensing methods may be used while volatile organic compound (VOC) sensing may be achieved when combined with a functionalization layer or device heating. These devices offer a great reduction in cost and offer increased mobility by allowing a "lab-on-chip" solution for the prospective user while also greatly reducing the amount of energy …

Development And Integration Of Mems Based Inductive Sensors, Luyang Zhang

Electronic Thesis and Dissertation Repository

Inductive sensors are one of the most widely used sensors especially in automotive. However, with the current PCB manufacture process, the large size of the sensor limits its usage in different applications. In this thesis, a novel method of fabricating bi-layer copper micro inductive sensor is demonstrated to solve the size issue. The two coil layers were built by UV LIGA process respectively, and a polyimide insulation film sandwiched in between. At the beginning, seeding layer was deposited on the substrate as electrode, and then the copper coil layer was created through electroplating in the patterned micromold. The coil was …

Optimal Sizing And Power Management Strategies Of Islanded Microgrids For Remote Electrification Systems, Faruk A. Bhuiyan

Electronic Thesis and Dissertation Repository

Over the past few years, electrification of remote communities with an efficient utilization of on-site energy resources has entered a new phase of evolution. However, the planning tools and studies for the remote microgrids are considered inadequate. Moreover, the existing techniques have not taken into account the impact of reactive power on component sizes. Thus, this thesis concentrates on optimal sizing design of an islanded microgrid (IMG), which is composed of renewable energy resources (RERs), battery energy storage system (BESS), and diesel generation system (DGS), for the purpose of electrifying off-grid communities. Owing to the utilization of both BESS and …

Coupled Electromagnetic And Thermal Analysis And Design Optimization Of Synchronous Electric Machines, Yi Wang

Theses and Dissertations

A new technique for coupling the electromagnetic, thermal, and air-flow analysis is proposed for electronically controlled synchronous machines. A computationally efficient finite element analysis (CE-FEA) technique is employed for the electromagnetic field analysis. An equivalent circuit network is used for thermal and air-flow analysis. An iterative algorithm, which exploits the fact that the type of machines studied have very low rotor losses and also a relatively reduced dependency of core losses with temperature and load, has been developed. The overall computational time is significantly reduced in comparison with the conventional coupling method, such that the new technique is highly suitable …

Design And Development Of Magneto-Rheological Actuators With Application In Mobile Robotics, Wenjun Li

Electronic Thesis and Dissertation Repository

In recent years, Magneto-Rheological (MR) fluids devices are widely studied and used for various purposes. Among these MR fluids devices, the MR actuator has attracted increasing attention for last two decades. An MR actuator is usually made of an active component (motor) and MR clutches. Compared with the regular actuators, the MR actuator features compliance due to the existence of MR fluids, which is commonly consider as benefits at the aspect of safety. On the other hand, the MR actuator has advantages on controllable bandwidth, torque-mass and torque-inertia ratios compared with the other compliant actuators.

In this study, a new …

Generation Scheduling For Power Systems With Demand Response And A High Penetration Of Wind Energy, Guodong Liu

Doctoral Dissertations

With renewable energy sources and demand response programs expanding in many power systems, traditional unit commitment and economic dispatch approaches are inadequate. The power system is changing to one where there is control with uncertainty for both generation and load. Alternative power system scheduling methods capable of aggregating the uncertainty of wind power and demand response, while maintaining reliable and economic performance are investigated in this work. The research addresses four aspects of these changes.

First, a probabilistic method is proposed to maintain uniform system reliability level in the hour-ahead economic dispatch by quantifying different levels of required spinning reserve. …

Resource Allocation For Wireless Relay Networks, Hanan Hassan Al-Tous

Dissertations

In this thesis, we propose several resource allocation strategies for relay networks in the context of joint power and bandwidth allocation and relay selection, and joint power allocation and subchannel assignment for orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) systems. Sharing the two best ordered relays with equal power between the two users over Rayleigh flat fading channels is proposed to establish full diversity order for both users. Closed form expressions for the outage probability, and bit error probability (BEP) performance measures for both amplify and forward (AF) and decode and forward (DF) cooperative communication …

Design And Implementation Of Position-Encoded Microfluidic Microsphere-Trap Arrays, Xiaoxiao Xu

All Theses and Dissertations (ETDs)

Microarray devices are useful for detecting and analyzing biological targets, such as DNAs, mRNAs, proteins, etc. Applications of microarrays range from fundamental research to clinical diagnostics and drug discovery. In this dissertation, we consider a microsphere array device with predetermined positions of the microspheres. The microspheres are conjugate on their surfaces with molecular probes to capture the targets, and the targets are identified by the microspheres' positions. We implement the microsphere arrays by employing microfluidic technology and a hydrodynamic trapping mechanism. We call our device microfluidic microsphere-trap arrays. To fully realize the potential of the device in biomedical applications, we …

Multidimensional Optimal Droop Control For Wind Resources In Dc Microgrids, Kaitlyn J. Bunker

Dissertations, Master's Theses and Master's Reports - Open

Two important and upcoming technologies, microgrids and electricity generation from wind resources, are increasingly being combined. Various control strategies can be implemented, and droop control provides a simple option without requiring communication between microgrid components. Eliminating the single source of potential failure around the communication system is especially important in remote, islanded microgrids, which are considered in this work. However, traditional droop control does not allow the microgrid to utilize much of the power available from the wind. This dissertation presents a novel droop control strategy, which implements a droop surface in higher dimension than the traditional strategy. The droop …

Oppositional Biogeography-Based Optimization, Mehmet Ergezer

ETD Archive

This dissertation outlines a novel variation of biogeography-based optimization (BBO), which is an evolutionary algorithm (EA) developed for global optimization. The new algorithm employs opposition-based learning (OBL) alongside BBO migration to create oppositional BBO (OB BO). Additionally, a new opposition method named quasi-reflection is introduced. Quasireflection is based on opposite numbers theory and we mathematically prove that it has the highest expected probability of being closer to the problem solution among all OBL methods that we explore. Performance of quasi-opposition is validated by mathematical analysis for a single-dimensional problem and by simulations for higher dimensions. Experiments are performed on benchmark …

Optimization In Microgrid Design And Energy Management, Tu Anh Nguyen

Doctoral Dissertations

"The dissertation is composed of three papers, which cover microgrid systems performance characterization, optimal sizing for energy storage system and stochastic optimization of microgrid operation. In the first paper, a complete Photovoltaic-Vanadium Redox Battery (VRB) microgrid is characterized holistically. The analysis is based on a prototype system installation deployed at Fort Leonard Wood, Missouri, USA. In the second paper, the optimal sizing of power and energy ratings for a VRB system in isolated and grid-connected microgrids is proposed. An analytical method is developed to solve the problem based on a per-day cost model in which the operating cost is obtained …