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2010

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Articles 31 - 60 of 5369

Full-Text Articles in Engineering

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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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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A Novel Phase-Locked-Loop And Its Application In Statcom System, L. Shi, Mariesa L. Crow Dec 2010

A Novel Phase-Locked-Loop And Its Application In Statcom System, L. Shi, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

Phase-Locked-Loop (PLL) plays important role in grid connected power electronics system. a good PLL system can detect the grid phase angle and frequency fast and accurately, and additionally it can extract the positive sequence exactly. in real applications, source signal (voltage or current) usually includes harmonic distortion, unbalanced components. Conventional PLL strategy cannot solve the unbalanced and harmonic distortion problems. Different PLL solutions are proposed in literature in recent years. the general considerations for these different approaches are to design positive sequence estimator to eliminate the negative sequence components and use filters to filter out the higher order harmonic distortions. …

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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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Distributed Grid Intelligence For Future Microgrid With Renewable Sources And Storage, Fanjun Meng, Ravi Akella, Mariesa L. Crow, Bruce Mcmillin Dec 2010

Distributed Grid Intelligence For Future Microgrid With Renewable Sources And Storage, Fanjun Meng, Ravi Akella, Mariesa L. Crow, Bruce Mcmillin

Electrical and Computer Engineering Faculty Research & Creative Works

The FREEDM microgrid is a smart grid solution with Distributed Grid Intelligence (DGI) to efficiently manage the power distribution and storage of renewable energy. within the FREEDM system, DGI applies distributed control method in a unique way to achieve feasible load balancing in microgrid by migrating power between renewable energy generation and storage at each node. This paper presents the key aspects in implementing such a scheme and outlines the preliminary results obtained by integrating the proposed methodology. the results demonstrate the potential benefits of adopting DGI control on a microgrid.

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Implementing Frequency Regulation Capability In A Solar Photovoltaic Power Plant, Venkata Ajay Kumar Pappu, Badrul H. Chowdhury, Ravi Bhatt Dec 2010

Implementing Frequency Regulation Capability In A Solar Photovoltaic Power Plant, Venkata Ajay Kumar Pappu, Badrul H. Chowdhury, Ravi Bhatt

Electrical and Computer Engineering Faculty Research & Creative Works

Photovoltaic power plants pose some challenges when integrated with the power grid. the PV plants always focus on extracting the maximum power from the arrays. This makes the PV system unavailable for helping in regulating the grid frequency as compared to conventional generators. the objective of this paper is to introduce a pseudo power point tracking which provides frequency regulation functionality to PV systems. This method is fast and helps in creating a reserve which can be utilized for frequency stability. Control technique discussed in this paper allows the control over the amount of active power injected into the grid. …

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Reconciling Motor Performance Indicators From Theoretical Calculations And Laboratory Tests, Himanshu Hirlekar, Badrul H. Chowdhury, Stephen Ruffing Dec 2010

Reconciling Motor Performance Indicators From Theoretical Calculations And Laboratory Tests, Himanshu Hirlekar, Badrul H. Chowdhury, Stephen Ruffing

Electrical and Computer Engineering Faculty Research & Creative Works

Quite often because of the complexity in the design of large industrial motors, the theoretical motor parameter calculations do not match actual results from laboratory tests. Thus, it becomes important to predict the amount of discrepancy between the two methods to develop confidence in the motor parameter calculations. This paper discusses the development of multiple artificial neural networks (ANNs) designed to predict the ratios of measured parameters to calculated parameters, given the geometry and construction of the motor. These ratios represent correction factors which can be applied to the values calculated from the theoretical program, which, in this case, is …

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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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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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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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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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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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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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Evaluation Of Hydraulic Efficiency Of Disinfection Systems Based On Residence Time Distribution Curves, Jordan M. Wilson, Subhas K. Venayagamoorthy Dec 2010

Evaluation Of Hydraulic Efficiency Of Disinfection Systems Based On Residence Time Distribution Curves, Jordan M. Wilson, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Hydraulic efficiency is a vital component in evaluating the disinfection capability of a contact system. Current practice evaluates these systems based upon the theoretical detention time (TDT) and the rising limb of the residence time distribution (RTD) curve. This evaluation methodology is expected because most systems are built based on TDT under a "black box" approach to disinfection system design. Within recent years, the proliferation of computational fluid dynamics (CFD) has allowed a more insightful approach to disinfection system design and analysis. Research presented in this study using CFD models and physical tracer studies shows that evaluation methods based upon …

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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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A Time-Domain Analysis Of Wave Force On Small-Scale Cylinders Of Offshore Structures, Bao-Lei Geng, Bin Teng, De-Zhi Ning Dec 2010

A Time-Domain Analysis Of Wave Force On Small-Scale Cylinders Of Offshore Structures, Bao-Lei Geng, Bin Teng, De-Zhi Ning

Journal of Marine Science and Technology–Taiwan

To get the accurate wave loads on the small-scale cylinders on the platforms, not only the incident wave but also the diffraction and radiation wave should be considered. By taking the wave diffraction from a fixed large-scale cylinder as an example, wave loads on small-diameter cylinders in the diffraction wave field are calculated by Morison formula in this paper. A time-domain numerical model on wave diffraction from large-scale structures is developed with a higher-order boundary element method (HOBEM). Then the velocity and acceleration of any water particle in the fluid domain can be produced from the solved diffraction potential. Results …

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Improving The Emulsion Stability Of Sponge Cake By The Addition Of ?-Polyglutamic Acid, Yung-Shin Shyu, Wen-Chieh Sung Dec 2010

Improving The Emulsion Stability Of Sponge Cake By The Addition Of ?-Polyglutamic Acid, Yung-Shin Shyu, Wen-Chieh Sung

Journal of Marine Science and Technology–Taiwan

The batter properties of sponge cake with the addition of γ-polyglutamic acid (PGA) at different levels (0.05, 0.1, 0.5 gkg-1, w/w) was evaluated. The viscosity, emulsion stability and foam stability increased at the addition of 0.5 gkg-1 PGA level. PGA caused significant declines in the differential scanning calorimetry (DSC) enthalpy, onset and peak temperatures of ice-melting transition of sponge cake. Sponge cakes manufactured with 0.5 gkg-1 PGA addition were in general lighter on crumb color and white index than the control. Scanning electron microscopy showed that sponge cake with the addition of 0.1 and 0.5 gkg-1 PGA exhibited microstructures having …

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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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Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David Dec 2010

Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David

Theses and Dissertations

A new technique, called nanoinjection, is being developed to insert foreign DNA into a living cell. Such DNA transfection is commonly used to create transgenic organisms vital to the study of genetics, immunology, and many other biological sciences. In nanoinjection, DNA, which has a net negative charge, is electrically attracted to a micromachined lance. The lance then pierces the cell membranes, and the voltage on the lance is reversed, repelling the DNA into the cell. It is shown that DNA motion is strongly correlated to ion transport through a process called electrophoresis. Gel electrophoresis is used to move DNA using …

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Sidescan Sonar Image Processing:Correcting Brightness Variation And Patching Gaps, Yet-Chung Chang, Shu-Kun Hsu, Ching-Hui Tsai Dec 2010

Sidescan Sonar Image Processing:Correcting Brightness Variation And Patching Gaps, Yet-Chung Chang, Shu-Kun Hsu, Ching-Hui Tsai

Journal of Marine Science and Technology–Taiwan

Sidescan sonar data are typically presented as gray level images. However, sidescan images often show striking variations in brightness. These variations, caused by the sonar beam pattern and the constantly changing attitude of the towfish, make the images difficult to read as pictures of the seabed. This reduces the utility of the images for marine geologists. In this paper, the effects of the sonar beam pattern across the swath are corrected using a normalization process based on the average signal intensity for each grazing angle. Noise along the track, which is generally caused by changes in the attitude of the …

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The Sensitivity Analysis Of A Mems Microphone With Different Membrane Diameters, Cheng-Ta Yang Dec 2010

The Sensitivity Analysis Of A Mems Microphone With Different Membrane Diameters, Cheng-Ta Yang

Journal of Marine Science and Technology–Taiwan

In MEMS capacitive microphone design, it is very critical to get highest yielding rate and sensitivity as the two major factors dominate structure design of microphone. The centralpost MEMS microphone is introduced in this paper to differentiate from traditional fixed membrane boundary microphone since the construction is simple and only few masks are required in the process so that the yielding can be greatly enhanced. Thus, it is necessary to find the relationship between the sensitivity and dimension of the diameter of the membrane. The main research steps described in this paper include using CoventorWarer to develop one analysis model …

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The Application Of E-Technology For Marine Information Service, Lien-Kwei Chien, Tsung-Shen Feng, Chieh-Cheng Yen, Beng-Chun Lee, Heng-Wen Chang Dec 2010

The Application Of E-Technology For Marine Information Service, Lien-Kwei Chien, Tsung-Shen Feng, Chieh-Cheng Yen, Beng-Chun Lee, Heng-Wen Chang

Journal of Marine Science and Technology–Taiwan

The purpose of this study is to establish the multi-function querying system by applying e-technology in marine data. Subjects tendency technology is new concept in system designing process of this study which originate from simulation language that was replace the structural technology. We also investigate the statistical characteristics of ocean waves and surges over Taiwan waters by cluster and return period analysis. Marine drifter track analysis and search area determination system were also analysis and import to GIS querying system. In order to make the locations of the near shore ships and sailing data could be easily convey through wireless …

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Stability Assessment For The Undersea Gas Pipeline, Wen-Chien Tseng, Lien-Kwei Chien, Sheng-Tse Chuang, Pei-Chi Tsai, Ya-Ting Hsu, Ting-Ting Lu, Chu-Kuan Lin Dec 2010

Stability Assessment For The Undersea Gas Pipeline, Wen-Chien Tseng, Lien-Kwei Chien, Sheng-Tse Chuang, Pei-Chi Tsai, Ya-Ting Hsu, Ting-Ting Lu, Chu-Kuan Lin

Journal of Marine Science and Technology–Taiwan

In general, the activities of harbour district, coastal construction and re-transportation of tide and current are all possible to influence the stability of research area and sediment environment in nearshore area. It indicates that status of deposit property of seabed and variability of sediment environment are important factors to stability and safety for the path of undersea gas pipeline. An assessment procedure and approach for the prediction of the wave-induced and earthquake-induced liquefaction potential and erosion potential are proposed for marine engineering practice. The soil sample of this study is obtained from deposit zone of gas pipeline of seabed in …

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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–Taiwan

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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The Performance Of Indium Tin Oxide Films Deposited On Plastic Substrate Applied For Solar-Cell Buoy, Chien-Kun Wang, Jyh-Jier Ho, Sung-Jen Nien, Yuang-Tung Cheng, William Lee, Chih-Chiang Lu, Bao-Shun Yau, Hsing-Wang Tsai, Chung-Cheng Chang Dec 2010

The Performance Of Indium Tin Oxide Films Deposited On Plastic Substrate Applied For Solar-Cell Buoy, Chien-Kun Wang, Jyh-Jier Ho, Sung-Jen Nien, Yuang-Tung Cheng, William Lee, Chih-Chiang Lu, Bao-Shun Yau, Hsing-Wang Tsai, Chung-Cheng Chang

Journal of Marine Science and Technology–Taiwan

In this paper, we report the indium tin oxide (ITO) films deposited on the polyethyene terephthalate (PET) substrate, which surface is treated with detergent solution. The ITO films are deposited on room temperature by direct current (DC) magnetron sputtering from a ceramic target of a 90% In-10% Sn alloy. The deposited opto-electric ITO films on PET with detergent treatment are 83.4% average visible transparency, and 5.8 × 10-4 Ω-cm resistivity, respectively. And then, we use the spin coating to form the polymer solar cell. Under optimal conditions of surface treatment and film deposition, the experimental result shows 2.12% of the …

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Signal Subspace Transformation For Direction-Of-Arrival Estimation Of Wideband Sources In Near Field, Lena Chang Dec 2010

Signal Subspace Transformation For Direction-Of-Arrival Estimation Of Wideband Sources In Near Field, Lena Chang

Journal of Marine Science and Technology–Taiwan

A novel adaptive signal subspace transformation for direction-of-arrival (DOA) estimation of wideband sources in the near-field is proposed in this paper. The method is composed of two transformations: signal subspace focusing (SSF) and far-field transformation (FFT). SSF aligns the signal subspaces for different frequencies in the bandwidth of the sources based on focusing matrices. FFT transforms the near-field steering vector to be the far-field steering vector with same direction-of-arrival (DOA) allocation. By the way, we simplify the location estimation of wideband sources in the near-field to be narrowband sources in the far field. The proposed method can track the DOAs …

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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–Taiwan

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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Response Analysis Of Concrete Piles Subjected To Lateral Impact, Helsin Wang, Ta-Peng Chang, Jin-Jun Wang Dec 2010

Response Analysis Of Concrete Piles Subjected To Lateral Impact, Helsin Wang, Ta-Peng Chang, Jin-Jun Wang

Journal of Marine Science and Technology–Taiwan

One-dimensional wave theory is assumed to interpret longitudinal waves impulse response or impact echo testing results in concrete piles. Transient flexural waves tests are alternatively introduced to evaluate piles where the tops are inaccessible for conventional longitudinal wave testing. The resulting interpretation for flexural waves based on one-dimensional wave theory is improper due to various velocities at low frequencies. In this research, treating a pile as a waveguide, three-dimensional wave theory provides the dispersion relation between phase flexural velocity and frequency. Using the resonance solutions and first-mode flexural wave curve is a simple and efficient method to find the resonant …

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The Study On The Asymptotic Profile And The Flow Patterns In Front Of A Long Bubble Through A Circular Tube, Cheng-Hsing Hsu, Chia-Chuan Kuo, Ching-Chuan Chang, Kuang-Yuan Kung Dec 2010

The Study On The Asymptotic Profile And The Flow Patterns In Front Of A Long Bubble Through A Circular Tube, Cheng-Hsing Hsu, Chia-Chuan Kuo, Ching-Chuan Chang, Kuang-Yuan Kung

Journal of Marine Science and Technology–Taiwan

Department of Civil Engineering, Army Academy, Chung-Li, Taoyuang, Taiwan, R.O.C

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