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2009

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Articles 2701 - 2730 of 4158

Full-Text Articles in Engineering

Post Treatment Alternatives For Stabilizing Desalinated Water, Susaye Douglas Jan 2009

Post Treatment Alternatives For Stabilizing Desalinated Water, Susaye Douglas

Electronic Theses and Dissertations

The use of brackish water and seawater desalination for augmenting potable water supplies has focused primarily on pre-treatment, process optimization, energy efficiency, and concentrate management. Much less has been documented regarding the impact of post-treatment requirements with respect to distribution system. The goals of this study were to review current literature on post-treatment of permeate water, use survey questionnaires to gather information on post-treatment water quality characteristics, gather operation information, review general capital and maintenance cost, and identify appropriate "lessons learned" with regards to post-treatment from water purveyors participating in the Project. A workshop was organized where experts from across …

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Percolation Study Of Nano-Composite Conductivity Using Monte Carlo Simulationpercolation, Jing Bai Jan 2009

Percolation Study Of Nano-Composite Conductivity Using Monte Carlo Simulationpercolation, Jing Bai

Electronic Theses and Dissertations

A Monte Carlo model is developed for predicting electrical conductivity of carbon nanofiber composite materials. The conductive nanofibers are models as both 2D and 3D network of finite sites that are randomly distributed. The percolation behavior of the network is studied using the Monte Carlo method, which leads to the determination of the percolation threshold. The effect of the nanofiber aspect ratio on the critical nanofiber volume rate is investigated in the current model, each of the nanofibers needs five independent geometrical parameters (i.e., three coordinates in space and two orientation angles) for its identification. There are three controlling parameters …

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Effect Of Finite Geometry On Solidification Microstructure In Beam-Based Fabrication Of Thin Wall Structures, Satish C. Kuchi Jan 2009

Effect Of Finite Geometry On Solidification Microstructure In Beam-Based Fabrication Of Thin Wall Structures, Satish C. Kuchi

Browse all Theses and Dissertations

With the advent of Rapid Protyping (RP) in the manufacturing industry, many newtechnologies came into development for quick fabrication of materials. One of the most versatile fabrication process among them is additive manufacturing. Laser based manufacturing (LBM) and electron beam manufacturing (EBM) processes use the energy from a laser or electron beam to build up structures layer by layer directly from powdered metals and wire feed stock. It has been determined from previous work that solidification cooling rate and thermal gradients are the important factors for controlling microstructure (grain size and morphology) and resulting mechanical properties of the deposit. The …

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A Fuzzy Set Theory Based Methodology For Analysis Of Uncertainties In Stage-Discharge Measurements And Rating Curve, Rajesh R. Shrestha, Slobodan P. Simonovic Jan 2009

A Fuzzy Set Theory Based Methodology For Analysis Of Uncertainties In Stage-Discharge Measurements And Rating Curve, Rajesh R. Shrestha, Slobodan P. Simonovic

Water Resources Research Report

River stage and discharge records are essential for hydrological and hydraulic analyses. While stage is measured directly, discharge value is calculated from measurements of flow velocity, depth and channel cross-section dimensions. The measurements are affected by random and systematic measurement errors and other inaccuracies, such as approximation of velocity distribution and channel geometry with a finite number of measurements. Such errors lead to the uncertainty in both, the stage and the discharge values, which propagates into the rating curve established from the measurements. The relationship between stage and discharge is not strictly single valued, but takes a looped form due …

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A Multicultural Comparison Of Engineering Students: Implications To Teaching And Learning, Zaki Shkair Seddigi, Luiz Fernando Capretz, David House Jan 2009

A Multicultural Comparison Of Engineering Students: Implications To Teaching And Learning, Zaki Shkair Seddigi, Luiz Fernando Capretz, David House

Electrical and Computer Engineering Publications

Problem statement: Personality considerations have become increasingly important in recent years, but studies involving the personality characteristics of engineers have been scarcely reported. Engineers today are expected to have a broader range of skills than in the recent past because users are now equally concerned with the technical as well as the personal services provided by engineers. Approach: A multicultural personality profile of engineering students had been presented in this study. The MBTI was used as an instrument to sort personality types of engineering students at both King Fahd University of Petroleum and Minerals in Saudi Arabia and University of …

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Electronic Tunability Of Ferroelectric Liquid Crystal Infiltrated Photonic Crystal Fibre, Sunish Mathews, Yuliya Semenova, Gerald Farrell Jan 2009

Electronic Tunability Of Ferroelectric Liquid Crystal Infiltrated Photonic Crystal Fibre, Sunish Mathews, Yuliya Semenova, Gerald Farrell

Articles

The electronic tunability of ferroelectric liquid crystal filled photonic crystal fibres is demonstrated for the first time. The tunability is obtained in the wavelength range of 1500 -1600 nm, with a free spectral range of ~ 20 nm. The electronic tunability is achieved by applying an electric field onto the infiltrated photonic crystal fibre which facilitates the photonic bandgap tuning owing to the microsecond order switching speeds of Ferroelectric Liquid crystals. The polarized transmission spectrum shows the behavior of a tunable notch filter with a change in applied voltage. The results obtained could pave the way for the fabrication of …

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Sms Fibre Structure For Temperature Measurement Using A Simple Intensity-Based Interrogation System, Agus Hatta, Ginu Rajan, Yuliya Semenova, Gerald Farrell Jan 2009

Sms Fibre Structure For Temperature Measurement Using A Simple Intensity-Based Interrogation System, Agus Hatta, Ginu Rajan, Yuliya Semenova, Gerald Farrell

Articles

A singlemode–multimode–singlemode (SMS) fibre structure for temperature measurement that utilises a simple intensity-based interrogation system is proposed. The temperature dependence of the SMS fibre structure utilised as a sensor is investigated numerically and experimentally. It is found that a strong temperature dependence for the SMS fibre structure exists at selected wavelengths. The temperature characteristic at such wavelengths is linear in nature and can be used for temperature measurements. The proposed temperature sensor offers a high resolution and accuracy, and also benefits from a simple configuration and low cost when compared to other fibre-optic temperature sensors.

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High Resolution Temperature Insensitive Interrogation Technique For Fbg Sensors, Qiang Wu, Yuliya Semenova, An Sun, Pengfei Wang, Gerald Farrell Jan 2009

High Resolution Temperature Insensitive Interrogation Technique For Fbg Sensors, Qiang Wu, Yuliya Semenova, An Sun, Pengfei Wang, Gerald Farrell

Articles

In this letter, we propose a high resolution temperature insensitive interrogation technique for FBG sensors where one FBG acts as an edge filter to interrogate a separate FBG sensor. A high resolution of better than 5 με in strain measurement range from 0 to 1100 με and the best resolution of better than 1 με were verified by experiments. An error of only ±2.2 με is achieved over a temperature range from 15 to 50 °C, indicating that this strain interrogation technique is temperature insensitive. Using an altered system configuration, the temperature was also measured simultaneously with a resolution better …

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Analysis Of Temperature Dependence For A Ratiometric Wavelength Measurement System Using Sms Fiber Structure Based Edged Filters, Agus Hatta, Yuliya Semenova, Ginu Rajan, Pengfei Wang, J. Zheng, Gerald Farrell Jan 2009

Analysis Of Temperature Dependence For A Ratiometric Wavelength Measurement System Using Sms Fiber Structure Based Edged Filters, Agus Hatta, Yuliya Semenova, Ginu Rajan, Pengfei Wang, J. Zheng, Gerald Farrell

Articles

Temperature dependence of an edge filter based on singlemode-multimodesinglemode (SMS) fiber structure is investigated numerically and experimentally. The experimental results and numerical results are in good agreement within an operational temperature range from 10 to 40 oC. It is found that the thermo-optic coefficient (TOC) has a more significant effect on the temperature dependence of an SMS edge filter compared to the thermal expansion coefficient (TEC). In the ratiometric wavelength measurement using two SMS edge filters, a small temperature variation can induce the ratio variation and in turn the wavelength measurement error. It is found the SMS edge filter’s response …

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Structural Segmentation Of Irish Traditional Music Using Chroma At Set Accented Tone Locations, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle Jan 2009

Structural Segmentation Of Irish Traditional Music Using Chroma At Set Accented Tone Locations, Cillian Kelly, Mikel Gainza, David Dorran, Eugene Coyle

Conference papers

An approach is presented which provides a structural segmentation of Irish Traditional Music. Chroma information is extracted at certain locations within the music. The resulting chroma vectors are compared to determine similar structural segments. Chroma is only calculated at "set accented tone" locatins within the music. "Set accented tones" are considered to be impervious to melodic variation and are entirely representative of an Irish Traditional tune. Results show that comparing "set accented tones" represented by chroma significantly increases the structural segmentation accuracy that when "set accented tones" are represented by pitch values.

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The Nature And Status Of Stem Professional Development: Effective Practices For Secondary Level Engineering Education, Rodney L. Custer, Jenny L. Daugherty Jan 2009

The Nature And Status Of Stem Professional Development: Effective Practices For Secondary Level Engineering Education, Rodney L. Custer, Jenny L. Daugherty

Reports of Center Studies

Recently engineering has emerged on the K-12 scene as a potentially important content area. However, K-12 teachers typically lack sufficient backgrounds to effectively integrate engineering into their classrooms. Thus teacher professional development is of critical importance. Although there have been several initiatives emerge to assist teachers in teaching engineering-related curriculum, there has been little empirical research generated. For example, little is known about best practices, engineering pedagogical content knowledge, or effective design principles for engineering professional development. Although there is a general consensus in the literature concerning a set of principles that differentiate effective teacher professional development (i.e., Garet, Porter, …

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Teacher Challenges To Implement Engineering Design In Secondary Technology Education (Part 3), Todd R. Kelley, Robert C. Wicklein Jan 2009

Teacher Challenges To Implement Engineering Design In Secondary Technology Education (Part 3), Todd R. Kelley, Robert C. Wicklein

Publications

This descriptive study examined the current status of technology education teacher practices with respect to engineering design. This article is the third article in a three-part series presenting the results of this study. The first article in the series titled Examination of Engineering Design Curriculum Content highlighted the research findings regarding engineering design curriculum content delivered by technology education teachers. The second article in the series titled Examination of Assessment Practices for Engineering Design Projects in Secondary Technology Education reported technology education teachers’ assessment practices when implementing engineering design projects in the classroom. The sample for this study was drawn …

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Examination Of Assessment Practices For Engineering Design Projects In Secondary Education (Part 1), Todd R. Kelley, Robert C. Wicklein Jan 2009

Examination Of Assessment Practices For Engineering Design Projects In Secondary Education (Part 1), Todd R. Kelley, Robert C. Wicklein

Publications

The following descriptive study was designed to determine the national status of secondary technology education curriculum content and assessment practices as they relate to engineering design. The results of this study were divided into a three-part article series. Although this study focused on the larger construct of the national status of the infusion of engineering design into technology education, three separate sub-constructs emerged. The three sub-constructs were: a) status of engineering design curriculum content; b) the status of assessment practices of engineering design projects, and c) what selected challenges are identified by secondary technology educators in teaching engineering design.

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Using Engineering Cases In Technology Education, Todd R. Kelley Jan 2009

Using Engineering Cases In Technology Education, Todd R. Kelley

Publications

The article discusses issues related to the use of engineering case studies in technology education in K-12 classrooms. Experts from K-12 education, universities, industry and U.S. government officials came to an agreement on the need to implement engineering in K-12 schools. In relation to the proposed use of engineering case studies in technology education, several definitions of the term "design case studies." The presentation of cases using multimedia formats is also cited as a powerful format of engineering design cases.

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Motivation While Designing In Engineering And Technology Education Impacted By Academic Preparation, Nathan Mentzer, Kurt Becker Jan 2009

Motivation While Designing In Engineering And Technology Education Impacted By Academic Preparation, Nathan Mentzer, Kurt Becker

Publications

The purpose of this study was to determine if high school students’ academic preparation was correlated with change in motivation during an engineering design challenge. The research was conducted in a high school classroom in which elements of engineering design were taught in a technology education context to eleventh-grade student from diverse academic backgrounds (measured by grade point average [GPA]). Participant motivation was assessed by the California Measure of Mental Motivation (CM3). The CM3 measures student motivation to apply critical thinking skills and reasoning to solve problems in five subscales: mental focus, learning orientation, creative problem solving, cognitive integrity, and …

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Time Relaxed Round Robin Tournament And The Nba Scheduling Problem, Renjun Bao Jan 2009

Time Relaxed Round Robin Tournament And The Nba Scheduling Problem, Renjun Bao

ETD Archive

This dissertation study was inspired by the National Basketball Association regular reason scheduling problem. NBA uses the time-relaxed round robin tournament format, which has drawn less research attention compared to the other scheduling formats. Besides NBA, the National Hockey League and many amateur leagues use the time-relaxed round robin tournament as well. This dissertation study is the first ever to examine the properties of general time-relaxed round robin tournaments. Single round, double round and multiple round time-relaxed round robin tournaments are defined. The integer programming and constraint programming models for those tournaments scheduling are developed and presented. Because of the …

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Application Of Dual-Energy Computed Tomography To The Evalution Of Coronary Atherosclerotic Plaque, Mitya M. Barreto Jan 2009

Application Of Dual-Energy Computed Tomography To The Evalution Of Coronary Atherosclerotic Plaque, Mitya M. Barreto

ETD Archive

Atherosclerotic coronary artery disease is responsible for around 50 of cardiovascular deaths in USA. Early detection and characterization of coronary artery atherosclerotic plaque could help prevent cardiac events. Computed tomography (CT) is an excellent modality for imaging calcifications and has higher spatial resolution than other common non-invasive modalities (e.g MRI), making it more suitable for coronary plaque detection. However, attenuation-based classification of non-calcified plaques as fibrous or lipid is difficult with conventional CT, which relies on a single x-ray energy. Dual-energy CT (DECT) may provide additional attenuation data for the identification and discrimination of plaque components. The purpose of this …

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Development Of A Focused Broadband Ultrasonic Transducer For High Resolution Fundamental And Harmonic Intravascular Imaging, Chaitanya K. Chandrana Jan 2009

Development Of A Focused Broadband Ultrasonic Transducer For High Resolution Fundamental And Harmonic Intravascular Imaging, Chaitanya K. Chandrana

ETD Archive

Intravascular ultrasound (IVUS) is increasingly employed for detection and evaluation of coronary artery diseases. Tissue Harmonic Imaging provides different tissue information that could additionally be used to improve diagnostic accuracy. However, current IVUS systems, with their unfocussed transducers, may not be capable of operating in harmonic imaging mode. Thus, there is a need to develop suitable transducers and appropriate techniques to allow imaging in multi modes for complementary diagnostic information. Focused PVDF TrFE transducers were developed using MEMS (Micro-Electro-Mechanical-Systems) compatible protocols. The transducers were characterized using pulse-echo techniques and exhibited broad bandwidth (110 at -6dB) with axial resolutions of Such …

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Altered Cortico-Cortical Brain Connectivity During Muscle Fatigue, Zhiguo Jiang Jan 2009

Altered Cortico-Cortical Brain Connectivity During Muscle Fatigue, Zhiguo Jiang

ETD Archive

Traditional brain activation studies using neuroimaging such as functional magnetic imaging (fMRI) have shown that muscle fatigue at submaximal intensity level is associated with increased brain activity in various cortical regions from low- to high-order motor centers. However, how these areas might interact remain unclear since previous activation studies related to motor control could not reveal information of between-area interaction. This issue can be addressed by evaluating brain activation data using the framework of connectivity analysis. Three types of brain connectivity, functional connectivity (FC), effective connectivity (EC) and structural connectivity (SC) have been examined to investigate the effect of voluntary …

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In-Situ Growth Of Porous Alumino-Silicates And Fabrication Of Nano-Porous Membranes, Pradeep Kodumuri Jan 2009

In-Situ Growth Of Porous Alumino-Silicates And Fabrication Of Nano-Porous Membranes, Pradeep Kodumuri

ETD Archive

Feasibility of depositing continuous films of nano-porous alumino-silicates, primarily zeolites and MCM-41, on metallic and non-metallic substrates was examined with an aim to develop membranes for separation of gaseous mixtures and also for application as hydrogen storage material. Mesoporous silica was deposited in-side the pores of these nano-porous disks with an aim to develop membranes for selective separations. Our study involves supported zeolite film growth on substrates using in-situ hydrothermal synthesis. Faujasite, Silicalite and Mesoporous silica have been grown on various metallic and non-metallic supports. Metallic substrates used for film growth included anodized titanium, sodium hydroxide treated Titanium, Anodized aluminum, …

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Imaging Of Tyramine-Substituted Hydrogels For Tissue Replacement, Ediuska V. Laurens Jan 2009

Imaging Of Tyramine-Substituted Hydrogels For Tissue Replacement, Ediuska V. Laurens

ETD Archive

Novel tyramine-based hyaluronan (HA) and collagen hydrogels have been developed in which cross-linking is accomplished via peroxidase-mediated dityramine linkages allowing direct cross-linking in vivo. These TB hydrogels possess advantageous physical properties, which include excellent biocompatibility and the ability to mimic the biological, structural and mechanical properties of normal, healthy tissues, including cartilage, and thus provide for synthetic, implantable biomaterials suitable for a wide range of tissue types. The efficacy of these TB-hydrogels has been previously tested in a number of clinically relevant animal models, which have evaluated their applicability for the repair/replacement of various tissues, including cartilage. Nevertheless, there exists …

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Semi-Automatic Segmentation Of Normal Female Pelvic Floor Structures From Magnetic Resonance Images, Xiaolong Li Jan 2009

Semi-Automatic Segmentation Of Normal Female Pelvic Floor Structures From Magnetic Resonance Images, Xiaolong Li

ETD Archive

Stress urinary incontinence (SUI) and pelvic organ prolapse (POP) are important health issues affecting millions of American women. Investigation of the cause of SUI and POP requires a better understand of the anatomy of female pelvic floor. In addition, pre-surgical planning and individualized treatment plans require development of patient-specific three-dimensional or virtual reality models. The biggest challenge in building those models is to segment pelvic floor structures from magnetic resonance images because of their complex shapes, which make manual segmentation labor-intensive and inaccurate. In this dissertation, a quick and reliable semi-automatic segmentation method based on a shape model is proposed. …

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Uncertainty Management Of Intelligent Feature Selection In Wireless Sensor Networks, Sanchita Mal-Sarkar Jan 2009

Uncertainty Management Of Intelligent Feature Selection In Wireless Sensor Networks, Sanchita Mal-Sarkar

ETD Archive

Wireless sensor networks (WSN) are envisioned to revolutionize the paradigm of monitoring complex real-world systems at a very high resolution. However, the deployment of a large number of unattended sensor nodes in hostile environments, frequent changes of environment dynamics, and severe resource constraints pose uncertainties and limit the potential use of WSN in complex real-world applications. Although uncertainty management in Artificial Intelligence (AI) is well developed and well investigated, its implications in wireless sensor environments are inadequately addressed. This dissertation addresses uncertainty management issues of spatio-temporal patterns generated from sensor data. It provides a framework for characterizing spatio-temporal pattern in …

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Two Approaches For Cell Retention In Perfusion Culture Systems, Zhaowei Wang Jan 2009

Two Approaches For Cell Retention In Perfusion Culture Systems, Zhaowei Wang

ETD Archive

A lack of efficient, economical, and reliable cell retention devices has limited the application of perfusion culture systems in the biopharmaceutical industry. Two types of cell retention devices were developed in this work for long-term perfusion culture systems: a modification of an inclined gravity settler and a variation of an ultrasonic filter. Both bench-top and large-scale tests showed that the gravity settler can effectively retain viable cells and preferentially remove nonviable cells in perfusion culture systems. The viable cell retention rate can be maintained well above 90 during long-term perfusion culture period while the nonviable cell retention rate is 20-30 …

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Cortical Bone Tissue Engineering;Scaffold Design And Cell Selection, Demin Wen Jan 2009

Cortical Bone Tissue Engineering;Scaffold Design And Cell Selection, Demin Wen

ETD Archive

Cortical bone tissue engineering provides a promising approach to generate graft materials needed to treat the large sized bone defects. The underling premise of tissue engineering is to mimic the in vivo microenvironment as best as possible in vitro culture system. To select an appropriate scaffold material used in this model system, mechanical and hydraulic permeability properties of 316L porous stainless steel and polymethylmethacrylate (PMMA) were studied, as well as their biocompatibility in short and long term cell culture. Results showed that scaffolds made of both stainless steel and PMMA: (1) could be manufactured to have similar permeability as that …

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On Active Disturbance Rejection Control;Stability Analysis And Applications In Disturbance Decoupling Control, Qing Zheng Jan 2009

On Active Disturbance Rejection Control;Stability Analysis And Applications In Disturbance Decoupling Control, Qing Zheng

ETD Archive

One main contribution of this dissertation is to analyze the stability characteristics of extended state observer (ESO) and active disturbance rejection control (ADRC). In particular, asymptotic stability of the dynamic system that describes the estimation error and the closed-loop system is established where the plant dynamics is completely known. In the face of large dynamic uncertainties, the estimation error, the closed-loop tracking error, and its up to the (n-1)st order derivatives are shown to be bounded. Furthermore, it is demonstrated that the error upper bounds, in general, monotonously decrease with the observer and control loop bandwidths. The second contribution is …

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Robotics Control Using Active Disturbance Rejection Control, Ousama Said Khairallah Jan 2009

Robotics Control Using Active Disturbance Rejection Control, Ousama Said Khairallah

ETD Archive

Conventional robotics control has been set in stone since the sixties. The world has been waiting too long for a new age of control to change the world of Robotics. Active Disturbance Rejection Control (ADRC) is a newly reformed Control methodology. It has been used, in very limited applications, as a replacement for PID control. In this thesis, I will cover the different aspects of the kinematics and dynamics of a robotic manipulator. I will also examine the feasibility of using ADRC to control a robotic manipulator. To explain ADRC, a simple example that demonstrates the concepts and theory of …

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The Synthesis And Characterization Of Novel Elastin-Like Polypeptides Containing An Oligomerization Domain, James T. Cole Jan 2009

The Synthesis And Characterization Of Novel Elastin-Like Polypeptides Containing An Oligomerization Domain, James T. Cole

ETD Archive

Elastin like polypeptides (ELPs) are an emerging class of biomaterials due to their unique group of chemical, physical and biological properties. We have constructed a library of ELPs based on the pentapeptide amino acid repeat sequence (GVGVP). ELPs exhibit lower critical solution temperature (LCST) transition behavior from a soluble phase below the transition temperature (Tt) to an insoluble two phase system above the transition temperature. This process is completely reversible so that ELPs can become soluble again upon lowering the temperature. This temperature can be tuned in many different ways at the molecular level by changing the composition of the …

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Biological Treatment Of Dietary Supplement Wastewater, Erick Benjamin Butler Jan 2009

Biological Treatment Of Dietary Supplement Wastewater, Erick Benjamin Butler

ETD Archive

Dietary supplement wastewater contains higher order polysaccharides such as the complex sugars maltodextrin and low fat milk. These complex sugars contain a significant amount of organic carbon therefore, presence of these sugars can pose threats to the environment if discharged without treatment. While many food processing plants are required to send their waste through wastewater treatment, legislation may require preliminary treatment of these wastes in order to satisfy the effluent discharge requirements. Because of the high organic carbon presence, it would be preferable to use biological treatment methods to reduce the organics present within the system. Microorganisms are capable of …

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Wind Flow Induced Vibrations Of Tapered Masts, Ahmad Bani-Hani Jan 2009

Wind Flow Induced Vibrations Of Tapered Masts, Ahmad Bani-Hani

ETD Archive

Structural dynamic analyses of elongated masts subjected to various wind speeds are presented in this work. The masts are modeled as vertically supported cantilever beams,with one end fixed to the ground, and the other end free. The external excitation forces acting of the masts are the results of vortex shedding represented by a sinusoidal time dependent functions. The frequencies of these sinusoidal functions are dictated by the Strouhal numbers associated of the flow regimes crossing over the masts. To enhance the vibratory behavior of a typical mast, under the influence of flow induced vibrations,three different mass distributions along the length …

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