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Fourier Transform Raman Spectroscopy For Process Control In The Petroleum Industry, Kent Lawson Wise

Chemistry & Biochemistry Theses & Dissertations

As early as 1950, Raman spectroscopy was proposed as a method to determine aromatics and olefins in hydrocarbon mixtures. Until recently, extensive use of Raman spectroscopy in the characterization of hydrocarbons has not been practical due to several limitations. One early limitation to Raman analysis was the absence of a high intensity and stable excitation source. This problem has been overcome with the advent of lasers. Another limitation was the presence of fluorescence in hydrocarbon fuels when excited by visible lasers. However, the development of Fourier-transform Raman spectrometers now allows Raman spectra to be collected using near-IR lasers (e.g …

Determination Of Anisotropy Of Granular Materials And Its Relation To Liquefaction Resistance Under Cyclic Loading, Omer Faruk Capar

Civil & Environmental Engineering Theses & Dissertations

Granular materials such as sand deposits have anisotropic characteristics due to the gravitational forces during depositional process and various stress histories. These anisotropic characteristics make evaluation of liquefaction resistance of soil very complex. Since obtaining undisturbed soil specimens for laboratory tests from discrete elements like sandy soils is very laborious, the soil specimens are reconstituted in laboratory with regards to the in-situ density of soil. Reconstituting the soil changes the soil fabric or anisotropic characteristics in comparison with field conditions. Many researchers have pointed out that liquefaction resistance is highly influenced by differences in the structure of the soil (or …

Validation Of Passive Air Sampling Monitors Onboard United States Navy Submarines, Larry A. Mcfarland

Community & Environmental Health Theses & Dissertations

An operating submarine creates a unique air quality mixture of compounds that result from a combination of human metabolism, construction materials, materials brought onboard and compounds created through the interaction of ship systems. A comprehensive study of submarine atmospheres is ongoing during deployments of U.S. Navy nuclear submarines. As part of the overall effort, a paired air sampling comparison field validation was conducted to compare the air sampling effectiveness of passive diffusive monitors compared to more traditional active air sampling methods when sampling for acrolein, formaldehyde and ozone in the enclosed submarine atmosphere. Acrolein monitors containing 2-hydroxymethylpiperidine (HMP) impregnated glass …

Design Of Adaptive Sliding Mode Fuzzy Control For Robot Manipulator Based On Extended Kalman Filter, Abdelrahman Aledhaibi

Mechanical & Aerospace Engineering Theses & Dissertations

In this work, a new adaptive motion control scheme for robust performance control of robot manipulators is presented. The proposed scheme is designed by combining the fuzzy logic control with the sliding mode control based on extended Kalman filter. Fuzzy logic controllers have been used successfully in many applications and were shown to be superior to the classical controllers for some nonlinear systems. Sliding mode control is a powerful approach for controlling nonlinear and uncertain systems. It is a robust control method and can be applied in the presence of model uncertainties and parameter disturbances, provided that the bounds of …

Signal Modeling With Non-Uniform Time Sampling Of Features For Automatic Speech Recognition, Montri Karnjanadecha

Electrical & Computer Engineering Theses & Dissertations

This dissertation presents an investigation of non-uniform time sampling methods for spectral/temporal feature extraction in speech. Frame-based features were computed based on an encoding of the global spectral shape using a Discrete Cosine Transform. In most current “standard” methods, trajectory (dynamic) features are determined from frame-based parameters using a fixed time sampling, i.e., fixed block length and fixed block spacing. In this research, new methods are proposed and investigated in which block length and/or block spacing are variable. The idea was initially tested with HMM-based isolated word recognition, and a significant performance improvement resulted when a variable block length and …

Resolution Of Overlapping Spectra By Wavelength Modulation Spectroscopy, Audra Michiele Bullock

Electrical & Computer Engineering Theses & Dissertations

Wavelength modulation absorption spectroscopy is a highly sensitive, non-intrusive technique for probing gaseous species, which employs the well-known principles of modulation spectroscopy in a novel way. With this technique, parameters such as velocity, density, and temperature can be measured with a high degree of precision. The research presented here shows that wavelength modulation is a convenient means of increasing the sensitivity of an absorption spectroscopy measurement because it allows for harmonic detection. The focus of the dissertation is resolution of overlapping spectra by harmonic detection and the advantages gained by performing detection at the higher harmonics, e.g., sixth and eighth. …

Advanced Atmospheric Water Vapor Dial Detection System, Tamer Refaat

Electrical & Computer Engineering Theses & Dissertations

Measurement of atmospheric water vapor is very important for understanding the Earth's climate and water cycle. The remote sensing Differential Absorption Lidar (DIAL) technique is a powerful method to perform such measurement from aircraft and space. This thesis describes a new advanced detection system, which incorporates major improvements regarding sensitivity and size. These improvements include a low noise advanced avalanche photodiode detector, a custom analog circuit, a 14-bit digitizer, a microcontroller for on board averaging and finally a fast computer interface.

This thesis describes the design and validation of this new water vapor DIAL detection system which was integrated onto …

Diffusion Problems In Wound Healing And A Scattering Approach To Immune System Interactions, Julia Suzanne Arnold

Mathematics & Statistics Theses & Dissertations

A theoretical model for the existence of a Critical Size Defect (CSD) in certain animals is the focus of the majority of this dissertation. Adam [1] recently developed a one-dimensional model of this phenomenon, and chapters I–V address the exist the CSD in a two-dimensional model and a three-dimensional model. The two dimensional (or 1-d circular) model is the more appropriate for a study of CSD's. In that model we assume a circular wound of uniform depth and develop a time-independent form of the diffusion equation relevant to the study of the CSD phenomenon. It transpires that the range of …

Curvilinear Interface Methodology For Finite-Element Applications, Ollie James Rose

Mechanical & Aerospace Engineering Theses & Dissertations

Recent trends in design and manufacturing suggest a tendency toward multiple centers of specialty which results in a need for improved integration methodology for dissimilar finite element or CFD meshes. Since a typical finite element or CFD analysis requires about 50% of an engineers effort to be devoted to modeling and input, there is a need to advance the state-of-the-art in modeling, methodology. These two trends indicate a need to for the capability to combine independently-modeled configurations in an automated and robust way without the need for global remodeling. One approach to addressing this need is the development of interfacing …

A Systems-Based Methodology For The Construction And Representation Of Organizational Knowledge Systems, Willie James Mcfadden

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to develop and apply a systems-based, analysis methodology which constructs and represents an organization's knowledge system. The research inquiry was guided by four questions: (1) “what is an organizational knowledge system?” (2) “how can it be made explicit?” (3) “does the representation accurately depict the organization's perspective of their unique knowledge system?” and (4) “what results from the deployment of the organizational knowledge system methodology?” The resultant answers to these research questions advanced and established the theoretical conception of an organization's knowledge system through the development of a methodology that fosters the construction and …

An Integrated Engineering-Computation Framework For Collaborative Engineering: An Application In Project Management, Hisham Mohamed El-Sayed Abdelsalam

Mechanical & Aerospace Engineering Theses & Dissertations

Today's engineering applications suffer from a severe integration problem. Engineering, the entire process, consists of a myriad of individual, often complex, tasks. Most computer tools support particular tasks in engineering, but the output of one tool is different from the others'. Thus, the users must re-enter the relevant information in the format required by another tool. Moreover, usually in the development process of a new product/process, several teams of engineers with different backgrounds/responsibilities are involved, for example mechanical engineers, cost estimators, manufacturing engineers, quality engineers, and project manager. Engineers need a tool(s) to share technical and managerial information and to …

Pulsed Optoacoustics In Solids, Zibiao Wei

Electrical & Computer Engineering Theses & Dissertations

Optoacoustic techniques are widely used to probe and characterize target materials including solids, liquids and gases. Included in such applications are diagnoses of thin films and semiconductor materials. The need to obtain greater spatial resolution requires the generation of shorter optoacoustic pulses. For such pulses, non-thermal effects may be quite important. On the other hand, even when an optoacoustic pulse is generated by an initially non-thermal technique, the thermal aspects become important in its evolution and propagation. The research undertaken in this Ph.D. dissertation included the generation and detection of optoacoustic signals through the thermal elastic mechanism. Several applications in …

Developing A Parametric Cost Model For Operating Costs Of Army Ground Combat Weapon Systems, James O. Winbush Jr.

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this research was to develop a parametric cost model for predicting operating costs of Army ground combat weapon systems. The model is intended to be used during the first two phases of the Army's acquisition process. The research necessary to develop the model was guided by two questions: what weapon system characteristics (such as weight, horsepower, fuel consumption, primary mission, NBC protection, fire control and night fighting capability) impact directly on operating ground combat systems; and what is the form of the parametric model for operating costs for ground combat systems? The study extends the bounds of …

Piezoceramic Actuator Placement For Acoustic Control Of Panels, Jeffrey S. Bevan

Mechanical & Aerospace Engineering Theses & Dissertations

Optimum placement of multiple traditional piezoceramic actuators is determined for active structural acoustic control of flat panels. The structural acoustic response is determined using acoustic radiation filters and structural surface vibration characteristics. Linear Quadratic Regulator (LQR) control is utilized to determine the optimum state feedback gain for active structural acoustic control. The optimum actuator location is determined by minimizing the structural acoustic radiated noise using a modified genetic algorithm. Experimental tests are conducted and compared to analytical results.

Anisotropic piezoceramic actuators exhibit enhanced performance when compared to traditional isotropic piezoceramic actuators. As a result of the inherent isotropy, these advanced …

Effects Of Ventilation On Human Thermal Comfort In Rooms, Ahmed F. Alfahaid

Mechanical & Aerospace Engineering Theses & Dissertations

Nowadays, the majority of people spend up to 90% of their time indoors; as a result, the maintenance of optimal indoor climate conditions has become important for their overall health and comfort. The main goal of this study is to predict numerically the flow and temperature patterns and the human thermal comfort conditions in an indoor environment using displacement ventilation.

A Computational Fluid Dynamics (CFD) code has been used to analyze thermal comfort conditions for a fullscale ventilated room. Unstructured grids have been used to discretize the numerical domain. Before undertaking a detailed investigation, the code was validated by comparing …

Multicast Services For Multimedia Collaborative Applications, Emad Eldin Mohamed Mohamed

Computer Science Theses & Dissertations

This work aims at providing multicast services for multimedia collaborative applications over large inter-networks such as the Internet. Multimedia collaborative applications are typically of small group size, slow group membership dynamics, and awareness of participants' identities and locations. Moreover, they usually consist of several components such as audio, video, shared whiteboard, and single user application sharing engines that collectively help make the collaboration session successful. Each of these components has its demands from the communication layer that may differ from one component to another. This dissertation identifies the overall characteristics of multimedia collaborative applications and their individual components. It also …