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2010

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Articles 31 - 60 of 6237

Full-Text Articles in Engineering

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu Dec 2010

Preference Queries In Large Multi-Cost Transportation Networks, Kyriakos Mouratidis, Yimin Lin, Man Lung Yiu

Kyriakos MOURATIDIS

Research on spatial network databases has so far considered that there is a single cost value associated with each road segment of the network. In most real-world situations, however, there may exist multiple cost types involved in transportation decision making. For example, the different costs of a road segment could be its Euclidean length, the driving time, the walking time, possible toll fee, etc. The relative significance of these cost types may vary from user to user. In this paper we consider such multi-cost transportation networks (MCN), where each edge (road segment) is associated with multiple cost values. We formulate …

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Extraction Of Contact Resistance In Carbon Nanofiber Via Interconnects With Varying Lengths, Ken Li, Patrick Wilhite, Vinit Khera, Shoba Krishnan, Xuhui Sun, Cary Y. Yang Dec 2010

Extraction Of Contact Resistance In Carbon Nanofiber Via Interconnects With Varying Lengths, Ken Li, Patrick Wilhite, Vinit Khera, Shoba Krishnan, Xuhui Sun, Cary Y. Yang

Electrical and Computer Engineering

A method to extract the contact resistance and bulk resistivity of vertically grown carbon nanofibers (CNFs) or similar one-dimensional nanostructures is described. Using a silicon-compatible process to fabricate a terrace test structure needed for the CNF length variation, the contact resistance is extracted by measuring in situ the resistances of individual CNFs with different lengths and within a small range of diameters using a nanoprober inside a scanning electron microscope. Accurate determination of contact resistances for various combinations of catalysts and underlayer metals can lead to eventual optimization of materials’ growth and device fabrication processes for CNF via interconnects.

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Florida Weatherization Training - Quarterly Report (October 2010-December 2010), Florida Solar Energy Center, Neil Moyer Dec 2010

Florida Weatherization Training - Quarterly Report (October 2010-December 2010), Florida Solar Energy Center, Neil Moyer

FSEC Energy Research Center®

The weatherization training for the State of Florida Dept of Community Affairs continues at the Florida Solar Energy Center's Training Facility. Progress for the sixth three months of the contract included a five day classroom training on October 18-22 (17 students) and in-field evaluations (16 students).

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Studies On The Preparation And Luminescence Properties Of Cadmium Selenide Quantum Dots, Their Immobilization, And Applications., Travis Justin Heath Dec 2010

Studies On The Preparation And Luminescence Properties Of Cadmium Selenide Quantum Dots, Their Immobilization, And Applications., Travis Justin Heath

Electronic Theses and Dissertations

Quantum dots are semiconductive particles whose properties are highly influenced by the presence of at least one electron. Cadmium selenide quantum dots were synthesized via colloidal synthesis. Contrary to previous preparations, more focus was placed on the temperature rather than the duration of time at which they form. A series of colored solutions were obtained because the excited quantum dots of various sizes emitted specific wavelengths of light. The emission spectra showed that the temperature-dependent quantum dots were successfully synthesized. The quantum dots were also immobilized on various surfaces, and the luminescence properties were examined. The quantum dots that were …

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High Impedance Arc Fault Detection In A Manhole Environment., Thomas Arthur Cooke Dec 2010

High Impedance Arc Fault Detection In A Manhole Environment., Thomas Arthur Cooke

Electronic Theses and Dissertations

The scope of this thesis was to develop a prototype high-impedance arc detection system that a utility worker could use as an early warning system while working in a manhole environment. As part of this system sensors and algorithms were developed to increase the sensitivity of detecting an arc while ignoring loads that can give false positive signatures for arcing. The latest technology was used to repeat measurements performed in previous research from decades ago that lacked in sampling speed and amplitude resolution. Several types of arcs were produced and analyzed so to establish a library of various waveform and …

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New Handheld Emissions Detector For Pinpointing The Location Of Inadvertently Energized Objects In Urban Environments., Kermit O. Phipps Dec 2010

New Handheld Emissions Detector For Pinpointing The Location Of Inadvertently Energized Objects In Urban Environments., Kermit O. Phipps

Electronic Theses and Dissertations

The power distribution infrastructure in the United States is deteriorating at a rapid rate exposing infrastructure wiring and creating potential shock hazards. Periodic road and sidewalk maintenance projects can also expose wiring and create energized objects. In urban settings inadvertently energized objects include: lamp posts, bus shelters, metal street curbs, sign posts, transformer vaults, and manhole covers as well as concrete and asphalt pavement. Every year electric shocks occur when people and domestic animals (such as dogs and cats) make incidental contact with these energized objects. In very rare cases the shocks from these contacts are lethal. Through current personal …

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Latency And Distortion Compensation In Augmented Environments Using Electromagnetic Trackers, Henry Himberg Dec 2010

Latency And Distortion Compensation In Augmented Environments Using Electromagnetic Trackers, Henry Himberg

Theses and Dissertations

Augmented reality (AR) systems are often used to superimpose virtual objects or information on a scene to improve situational awareness. Delays in the display system or inaccurate registration of objects destroy the sense of immersion a user experiences when using AR systems. AC electromagnetic trackers are ideally for these applications when combined with head orientation prediction to compensate for display system delays. Unfortunately, these trackers do not perform well in environments that contain conductive or ferrous materials due to magnetic field distortion without expensive calibration techniques. In our work we focus on both the prediction and distortion compensation aspects of …

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Effective Ionic Conductivity Of A Novel Intermediate-Temperature Mixed Oxide-Ion And Carbonate-Ion Conductor, Xue Li, Guoliang Xiao, Kevin Huang Dec 2010

Effective Ionic Conductivity Of A Novel Intermediate-Temperature Mixed Oxide-Ion And Carbonate-Ion Conductor, Xue Li, Guoliang Xiao, Kevin Huang

Faculty Publications

A systematic investigation on the effective ionic conductivity (σm) of a novel intermediate-temperature mixed oxide-ion and carbonate-ion conductor MOCC consisting of a ceria phase and a carbonate phase is reported. The study explicitly shows that the observed remarkable temperature-dependent σm is primarily the result of softening/melting of the carbonate phase as the physical state of the carbonate phase transforms from solid, softened to molten. Differential scanning calorimetry analysis complements the understanding of the observed electrical behavior by revealing temperatures of melting and solidification in agreement with the onset temperatures of σm. In addition, the …

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Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust Dec 2010

Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust

Theses and Dissertations

Multiple fans are sometimes used in an array configuration to cool various types of electronic equipment. In addition to adding another noise source, using two fans with closely spaced blade passage frequencies (BPF) can create an annoying beat frequency. A two fan array with each fan having a different BPF was considered. The fans were theoretically modeled at the BPF and first harmonics. Each fan has two acoustic paths to the far field. Thus, each fan was modeled as a two source array. The first control configuration consisted of one control filter using six control sources and six error sensors …

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Effects Of Warm-Mix Asphalt Additives On Asphalt Mixture Characteristics And Pavement Performance, Jun Zhang Dec 2010

Effects Of Warm-Mix Asphalt Additives On Asphalt Mixture Characteristics And Pavement Performance, Jun Zhang

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The primary objective of this research is to evaluate the feasibility of several WMA mixtures as potential asphalt paving mixtures for Nebraska pavements. To that end, three well-known WMA additives (i.e., Sasobit, Evotherm, and Advera synthetic zeolite) were evaluated. For a more realistic evaluation of the WMA approaches, trial pavement sections of the WMA mixtures and their HMA counterparts were implemented in Antelope County, Nebraska. More than one ton of field-mixed loose mixtures were collected at the time of paving and were transported to the NDOR and UNL laboratories to conduct comprehensive laboratory evaluations and pavement performance predictions of the …

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Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill Dec 2010

Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill

Theses and Dissertations

To simplify the measurement of energy-based structural metrics, a general registration process for the scanning laser doppler vibrometer (SLDV) has been developed. Existing registration techniques, also known as pose estimation or position registration, suffer from mathematical complexity, instrument specificity, and the need for correct optimization initialization. These difficulties have been addressed through development of a general linear laser model and hybrid registration algorithm. These are applicable to any SLDV and allow the registration problem to be solved using straightforward mathematics. Additionally, the hybrid registration algorithm eliminates the need for correct optimization initialization by separating the optimization process from solution selection. …

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Sizing Of Header And Flushing Manifolds For Row Crop Drip, Charles M. Burt, Stuart W. Styles Dec 2010

Sizing Of Header And Flushing Manifolds For Row Crop Drip, Charles M. Burt, Stuart W. Styles

Charles M. Burt

No abstract provided.

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Critical Analysis On The Structural And Magnetic Properties Of Bulk And Nanocrystalline Cu-Fe-O, D. Paul Joseph, C. Venkateswaran, R. Selva Vennila Dec 2010

Critical Analysis On The Structural And Magnetic Properties Of Bulk And Nanocrystalline Cu-Fe-O, D. Paul Joseph, C. Venkateswaran, R. Selva Vennila

Center for Study of Matter at Extreme Conditions

Nanocrystalline and bulk samples of “Fe”-doped CuO were prepared by coprecipitation and ceramic methods. Structural and compositional analyses were performed using X-ray diffraction, SEM, and EDAX. Traces of secondary phases such as CuFe2O4, Fe3O4, and α-Fe2O3 having peaks very close to that of the host CuO were identified from the Rietveld profile analysis and the SAED pattern of bulk and nanocrystalline Cu0.98Fe0.02O samples. Vibrating Sample Magnetometer (VSM) measurements show hysteresis at 300 K for all the samples. The ferrimagnetic Neel transition temperature () was found …

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Development Of A Rigid Body Computational Model For Investigation Of Wrist Biomechanics, Benjamin Majors Dec 2010

Development Of A Rigid Body Computational Model For Investigation Of Wrist Biomechanics, Benjamin Majors

Theses and Dissertations

The wrist is one of the most complex joints in the human body. As such, the wrist joint is difficult to model due to the number of bones involved and its intricate soft tissue interactions. Many studies have attempted modeling the wrist previously; however, the majority of these studies simplify the joint into two-dimensions or idealized mechanical joints to reduce the complexity of the simulation. While these approaches still yield valuable information, the omission of a third-dimension or geometry defined movements limits the models’ usefulness in predicting joint function under non-idealized conditions. Therefore, the goal of this study was to …

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Arithmetic Units For The Elliptic Curve Cryptography With Concurrent Error Detection Capability, Arash Hariri Dec 2010

Arithmetic Units For The Elliptic Curve Cryptography With Concurrent Error Detection Capability, Arash Hariri

Electronic Thesis and Dissertation Repository

The elliptic curve cryptography is an important branch in public-key cryptography. In this thesis, we consider the elliptic curve cryptography over binary extension fields from two different points of view. First, we investigate the underlying arithmetic operations in the elliptic curve cryptography. The main arithmetic operation is the scalar multiplication. This operation is based on two elliptic curve operations, known as the point addition and point doubling. Implementing these two elliptic curve operations requires finite field arithmetic, specifically, finite field addition, multiplication, squaring, and inversion. We focus on two finite field operations, namely finite field multiplication and squaring. For the …

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The Use Of Building Information Modeling In Generating Hard Bid Estimates, Peter Samuel Jensen Dec 2010

The Use Of Building Information Modeling In Generating Hard Bid Estimates, Peter Samuel Jensen

Theses and Dissertations

Building Information Modeling has provided many benefits to the architectural, engineering, construction and facilities management communities. Many studies have been done to validate the asserted benefits, including benefits to the field of estimating. The studies on estimating are currently limited to the realm of conceptual estimates, and have only treated detailed estimates in the abstract. The purpose of this study was to determine how BIM was being used by companies in a hard bid, or detailed estimate scenario. The research team used the Deseret Towers housing project at Brigham Young University as the basis for the research. A building information …

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Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii Dec 2010

Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii

Theses and Dissertations

Friction stir welding (FSW) of steel is often performed with an insert made of polycrystalline cubic boron nitride (PCBN). Specifically, MS80 is a grade of PCBN made by Smith MegaDiamond that has been optimized for the FSW process. The PCBN insert is attached to a tungsten carbide (WC) shank by a compression fitting. However, FSW tools manufactured by this method inevitably fail by fracture in the PCBN. Permanently bonding PCBN to WC would likely solve the fracturing problem and increase the life of PCBN FSW tools to be economically viable. Partial transient liquid phase (PTLP) bonding, a process used to …

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Eit, Slow Light, And Sealing Methods For Embedding Rubidium Into The Arrow System, Katherine Barnett Hurd Dec 2010

Eit, Slow Light, And Sealing Methods For Embedding Rubidium Into The Arrow System, Katherine Barnett Hurd

Theses and Dissertations

Light-matter interactions are fundamentally based on the quantum mechanical principles that govern photons, electrons and other fundamental particles. One very interesting phenomenon within all of light-matter interactions is Electromagnetically Induced Transparency(EIT). This phenomenon causes an otherwise absorbing atomic transition to stop absorbing through quantum mechanical interference of probability wave functions. Corresponding to that change in absorption, will be a sudden, large change in the index of refraction. This change in the index of refraction leads to another phenomenon in which the group velocity of light can be slowed down dramatically. In the past, many researchers have been able to achieve …

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A Comparative Verification Of Forecasts From Two Operational Solar Wind Models, Donald C. Norquist, Warner C. Meeks Dec 2010

A Comparative Verification Of Forecasts From Two Operational Solar Wind Models, Donald C. Norquist, Warner C. Meeks

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The solar wind (SW) and interplanetary magnetic field (IMF) have a significant influence on the near‐Earth space environment. In this study we evaluate and compare forecasts from two models that predict SW and IMF conditions: the Hakamada‐Akasofu‐Fry (HAF) version 2, operational at the Air Force Weather Agency, and Wang‐Sheeley‐Arge (WSA) version 1.6, executed routinely at the Space Weather Prediction Center. SW speed (Vsw) and IMF polarity (Bpol) forecasts at L1 were compared with Wind and Advanced Composition Explorer satellite observations. Verification statistics were computed by study year and forecast day. Results revealed that both models’ mean Vsw are …

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Evaluation Of Micro Irrigation Systems, Charles M. Burt, Robert E. Walker, Stuart W. Styles Dec 2010

Evaluation Of Micro Irrigation Systems, Charles M. Burt, Robert E. Walker, Stuart W. Styles

Stuart W. Styles

No abstract provided.

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Fotogrametría Terrestre Aplicada A Modelos Físicos Del Laboratorio De Procesos Geotécnicos, Marinela Pinzón Muñóz Dec 2010

Fotogrametría Terrestre Aplicada A Modelos Físicos Del Laboratorio De Procesos Geotécnicos, Marinela Pinzón Muñóz

Ingeniería Civil

No abstract provided.

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Irrigation District Turnouts, Charles M. Burt Dec 2010

Irrigation District Turnouts, Charles M. Burt

BioResource and Agricultural Engineering

This is meant to be a very quick, roughly written primer on irrigation district turnout selection. It by no means covers all of the details, but it might help out. ITRC offers flow measurement classes, with online registration at www.itrc.org. We have also done testing on quite a few designs over the years, but the work was almost all confidential in nature.

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Modeling Of Aortic Valve Anatomic Geometry From Clinical Multi Detector-Row Computed Tomography Images, Gregory A. Book Dec 2010

Modeling Of Aortic Valve Anatomic Geometry From Clinical Multi Detector-Row Computed Tomography Images, Gregory A. Book

Master's Theses

Transcatheter aortic valve implantation (TAVI) is an emerging and viable alternative to surgical valve replacement. A TAVI procedure involves insertion of a catheter into the heart through an artery or transapically, and expanding valve stent in place. This procedure dramatically reduces the recovery time by eliminating the need for open heart surgery. Understanding the biomechanics of the stent-valve interaction is crucial for proper device deployment and function. In this study, we examine the extraction of valve geometries and creation of valve models from multi-detector row computed tomography (MDCT) images that may eventually be used to model stent expansion on a …

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Universality Of Non-Ohmic Shunt Leakage In Thin-Film Solar Cells, Sourabh Dongaonkar, J. D. Servaites, G. M. Ford, S. Loser, R. M. Gelfand, H. Mohseni, Hugh Hillhouse, R. Agrawal, M. A. Ratner, T. J. Marks, Mark S. Lundstrom, Muhammad A. Alam Dec 2010

Universality Of Non-Ohmic Shunt Leakage In Thin-Film Solar Cells, Sourabh Dongaonkar, J. D. Servaites, G. M. Ford, S. Loser, R. M. Gelfand, H. Mohseni, Hugh Hillhouse, R. Agrawal, M. A. Ratner, T. J. Marks, Mark S. Lundstrom, Muhammad A. Alam

Other Nanotechnology Publications

We compare the dark current-voltage (IV) characteristics of three different thin-film solar cell types: hydrogenated amorphous silicon (a-Si:H) p-i-n cells, organic bulk heterojunction (BHJ) cells, and Cu(In, Ga)Se-2 (CIGS) cells. All three device types exhibit a significant shunt leakage current at low forward bias (V < similar to 0.4) and reverse bias, which cannot be explained by the classical solar cell diode model. This parasitic shunt current exhibits non-Ohmic behavior, as opposed to the traditional constant shunt resistance model for photovoltaics. We show here that this shunt leakage (I-sh), across all three solar cell types considered, is characterized by the following common phenomenological features: (a) voltage symmetry about V = 0, (b) nonlinear (power law) voltage dependence, and (c) extremely weak temperature dependence. Based on this analysis, we provide a simple method of subtracting this shunt current component from the measured data and discuss its implications on dark IV parameter extraction. We propose a space charge limited (SCL) current model for capturing all these features of the shunt leakage in a consistent framework and discuss possible physical origin of the parasitic paths responsible for this shunt current mechanism. (C) 2010 American Institute of Physics. [doi:10.1063/1.3518509]

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Mapping The Flip Angle In Magnetic Resonance Imaging Using The Accelerated 3d Look-Locker Sequence, Trevor P. Wade Dec 2010

Mapping The Flip Angle In Magnetic Resonance Imaging Using The Accelerated 3d Look-Locker Sequence, Trevor P. Wade

Electronic Thesis and Dissertation Repository

In the ongoing quest to extract more information from MRI images, there has arisen a need to rapidly map the flip angle. This has been primarily driven by the shift to stronger main field strengths, which bring with them improved SNR, but also new difficulties. In particular, the radio frequency field used to excite the magnetization can no longer be assumed uniform at field strengths of 3 Tesla and above. New rapid quantitative imaging techniques, such as DESPOT1 and DESPOT2, rely on accurate knowledge of the flip angle, and while this could safely be assumed to be the prescribed value …

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Wake Dynamics And Passive Flow Control Of A Blunt Trailing Edge Profiled Body, Lakshmana Sampat Doddipatla Dec 2010

Wake Dynamics And Passive Flow Control Of A Blunt Trailing Edge Profiled Body, Lakshmana Sampat Doddipatla

Electronic Thesis and Dissertation Repository

Wake flows behind two-dimensional bodies are dominated mainly by two types of coherent structures, namely, the Karman Benard vortices and the streamwise vortices, also referred to as rolls and ribs respectively. The three-dimensional wake instabilities lead to distinct instability modes (mode-A, mode-B and mode-C or mode S) depending on the flow Reynolds number and geometric shape. The present investigation explores the mechanism by which the flow transitions take place to three-dimensionality in the near wake of a profiled leading edge and blunt trailing edge body. Experiments consisting of a combination of Planar Laser Induced Fluorescence visualizations and Particle Image Velocimetry …

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Incorporating Feedback From Multiple Sensory Modalities Enhances Brain–Machine Interface Control, Aaron J. Suminski, Dennis C. Tkach, Andrew H. Fagg, Nicholas G. Hatsopoulos Dec 2010

Incorporating Feedback From Multiple Sensory Modalities Enhances Brain–Machine Interface Control, Aaron J. Suminski, Dennis C. Tkach, Andrew H. Fagg, Nicholas G. Hatsopoulos

Biomedical Engineering Faculty Research and Publications

The brain typically uses a rich supply of feedback from multiple sensory modalities to control movement in healthy individuals. In many individuals, these afferent pathways, as well as their efferent counterparts, are compromised by disease or injury resulting in significant impairments and reduced quality of life. Brain–machine interfaces (BMIs) offer the promise of recovered functionality to these individuals by allowing them to control a device using their thoughts. Most current BMI implementations use visual feedback for closed-loop control; however, it has been suggested that the inclusion of additional feedback modalities may lead to improvements in control. We demonstrate for the …

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A New Calibration Method For Low Cost Mems Inertial Sensor Module, Sheng-Chih Shen, Chia-Jung Chen, Hsin-Jung Huang Dec 2010

A New Calibration Method For Low Cost Mems Inertial Sensor Module, Sheng-Chih Shen, Chia-Jung Chen, Hsin-Jung Huang

Journal of Marine Science and Technology

This paper presents a new calibration method to overcome the challenges of MEMS inertial sensors for underwater navigation. The MEMS inertial sensor module is composed of an accelerometer, a gyroscope and a circuit of signal process. For navigation estimation, it is easy to be influenced by errors which come from MEMS inertial sensors. In general, the sources of error can be categorized into two groups, deterministic type and stochastic type. The former primarily includes bias errors, misalignment and nonlinearity; the latter contains temperature effect and signal drifting. Subsequently, the linearity calibration is used to modify the deterministic error and the …

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Determining The Cyclic Strength Of Geomaterials Under Low Frequency Cyclic Loading With Acoustic Emission, Helsin Wang, Ta-Peng Chang, Ju-Jiang Hung Dec 2010

Determining The Cyclic Strength Of Geomaterials Under Low Frequency Cyclic Loading With Acoustic Emission, Helsin Wang, Ta-Peng Chang, Ju-Jiang Hung

Journal of Marine Science and Technology

Acoustic emission is traditionally regarded as an explicit measurable index for microcracking in geomaterials. An accelerative cracking point is first introduced based on the different characteristics of acoustic emission at stable fracture propagation stage. Accelerative cracking point is located between the fracture initiation strength and critical energy release point, a point causing a fatal uncontrolled fracture in materials. Microcracking dominates the real mechanical characteristics in the materials, not reflected on the conventional mechanical experimental results as the stress level beyond the accelerative cracking point at the stable fracture propagation stage. At this stage, non-stress-controlled fracture in materials could arise as …

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Fast Block Motion Estimation With Edge Alignment On H.264 Video Coding, Chi-Han Chuang, Chien-Hua Su, Shyi-Chyi Cheng Dec 2010

Fast Block Motion Estimation With Edge Alignment On H.264 Video Coding, Chi-Han Chuang, Chien-Hua Su, Shyi-Chyi Cheng

Journal of Marine Science and Technology

This paper presents a novel block matching scheme with edge alignment strategy on H.264 video coding, which uses multiple references and multiple block sizes for motion estimation in order to improve the rate-distortion performance. In H.264, the computational complexity is linearly dependent on the number of allowed reference frames and block sizes using the full exhaustive search. Many fast block-matching algorithms reduce the computational complexity of motion estimation by carefully designing the search patterns with different shapes or sizes which have significant impact on the search speed and distortion performance. However, the search speed and the distortion performance conflict often …

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