Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Journal

Discipline
Institution
Keyword
Publication Year
Publication
File Type

Articles 21871 - 21900 of 27416

Full-Text Articles in Engineering

Hydrothermal Stability Of The Davisil/Cab-O-Sil Silica Catalyst Carriers, Clint G. Guymon, Dr. Calvin H. Bartholomew Aug 2013

Hydrothermal Stability Of The Davisil/Cab-O-Sil Silica Catalyst Carriers, Clint G. Guymon, Dr. Calvin H. Bartholomew

Journal of Undergraduate Research

The Fischer-Tropsch Synthesis (FTS) sustained Germany’s fuel needs during World War II as well as South Africa’s since the 1960’s.1 This catalytic technology is enthralling and left to the interested reader to reap in the deluge of information present in the literature. The principle reaction in FTS is a simple polymerization: nCO + 2nH2 ­ [-CH2-]n + nH2O, over a metal such as iron or cobalt. This paper focuses on the problem of hydrothermal stability of silicasupported cobalt FTS catalyst.

Go to article

Rectangular Carbon Fiber Isotruss Reinforcement In Concrete Beams, David Jarvis, Dr. David Jensen, Dr. Fernando Fonseca Aug 2013

Rectangular Carbon Fiber Isotruss Reinforcement In Concrete Beams, David Jarvis, Dr. David Jensen, Dr. Fernando Fonseca

Journal of Undergraduate Research

The objective of this research was to determine the flexural strength of concrete beams reinforced by the rectangular carbon fiber IsoTruss. The rectangular IsoTruss is a threedimensional composite grid structure patented by Brigham Young University. It is a modification of the regular IsoTruss that is also being researched at Brigham Young University.

Go to article

Internal Cleave And Fill: A Method For Internal Refinement Of All-Hexahedral Swept Meshes, Michael Borden, Dr. Steven E. Benzley Aug 2013

Internal Cleave And Fill: A Method For Internal Refinement Of All-Hexahedral Swept Meshes, Michael Borden, Dr. Steven E. Benzley

Journal of Undergraduate Research

Three-dimensional finite element analysis (FEA) is an important design tool for scientists and engineers. Before the analysis can begin, a continuous domain must be subdivided into small elements (i.e., finite elements). The process of subdividing a continuous domain is called meshing. There is currently significant research being devoted to the generation of such meshes. Tetrahedral meshes are well developed and have been incorporated in numerous software packages. Hexahedral meshes provide some advantages over tetrahedral meshes but are currently more restrictive in the geometrical shapes they can fill.[1]

Go to article

Modeling Power Consumption In Field Programmable Logic Devices, Benjamin L. Bullough, Dr. Michael Wirthlin Aug 2013

Modeling Power Consumption In Field Programmable Logic Devices, Benjamin L. Bullough, Dr. Michael Wirthlin

Journal of Undergraduate Research

Some of the most important application areas for integrated circuits are in portable communication and computing devices. Since batteries power these devices, power is only available in limited quantities. Optimizing for power allows engineers to produce designs, which extend battery life or use a smaller battery to save volume and weight. The excess heat produced by electrical equipment is also directly related to power consumption and is an important consideration in many applications.

Go to article

Determination Of Mortar Saturation Methods Based On Mri Scanning Image, Hsiang-Wei Chiang, Ran Huang Aug 2013

Determination Of Mortar Saturation Methods Based On Mri Scanning Image, Hsiang-Wei Chiang, Ran Huang

Journal of Marine Science and Technology–Taiwan

Magnetic resonance imaging (MRI) is widely used in the medical field and among one of the greatest inventions in recent years. In MRI images, the bright zone denotes signals that are generated by water in the specimen. However, solid cement-based materials lack water. Therefore, developing a method to achieve optimal saturation for cement-based materials is crucial for MRI scanning. In this study, the immersion, boiling, and vacuum methods were used to achieve saturation for various mortar specimens with w/c ratios of 0.45, 0.55, and 0.65. By comparing MRI images and absorption test results, we found that the vacuum method tends …

Go to article

Identification Of Pipelines From The Secondary Reflect Wave Travel Time Of Ground-Penetrating Radar Waves, Kun-Fa Lee, Tan-K Wang1, Yu-Ming Kang, Cheng-Sung Wang, Kuo-An Lin Aug 2013

Identification Of Pipelines From The Secondary Reflect Wave Travel Time Of Ground-Penetrating Radar Waves, Kun-Fa Lee, Tan-K Wang1, Yu-Ming Kang, Cheng-Sung Wang, Kuo-An Lin

Journal of Marine Science and Technology–Taiwan

When using ground-penetrating radar to identify underground pipelines of similar dielectric constants (i.e. PE and PVC), misidentification is quite common. In this study, we apply reflected travel time of radar waves into the PE- and PVC- dielectric constants and the differentiation becomes possible. We have conducted the experiments using the nonmetal PE- and PVC- pipelines as well as the heavy metal (iron) pipelines in a water environment. Based on a travel- time calculation, the dielectric constants of non-metal pipelines with similar composition (PE ＝ 2.3 and PVC ＝ 3.0) were quite close. The error between the experimental and theoretical values …

Go to article

Bayesian-Network-Based Hydro-Power Fault Diagnosis System Development By Fault Tree Transformation, Chaur-Gong Jong, Sou-Sen Leu Aug 2013

Bayesian-Network-Based Hydro-Power Fault Diagnosis System Development By Fault Tree Transformation, Chaur-Gong Jong, Sou-Sen Leu

Journal of Marine Science and Technology–Taiwan

Currently, fault diagnosis of reservoir facilities relies mostly on check-list evaluation. The results and qualities of evaluation are limited by experience and ability of the evaluators, which may not achieve the goal of systematic assessment in a consistent manner. To overcome the limitation of the traditional approach, this research develops a fault diagnosis and evaluation system for reservoir facility by utilizing multi-state Fault-Tree Analysis (FTA) technique, in conjunction with Bayesian Networks (BN) which incorporate expert experiences through lateral linkages among BN nodes and weighting factors. The system has been used to analyze and verify against three hydro-power systems currently in …

Go to article

A Lean Prebid Planning Model For Construction Contractors: A Case Study In Vietnam, Hui Ping Tserng, Samuel Yen-Liang Yin, Thanh Long Ngo Aug 2013

A Lean Prebid Planning Model For Construction Contractors: A Case Study In Vietnam, Hui Ping Tserng, Samuel Yen-Liang Yin, Thanh Long Ngo

Journal of Marine Science and Technology–Taiwan

Prebid planning is an essential function of construction project management that allows contractors to obtain projects with low cost while achieving other criteria. It also helps contractors during project execution and management. This research applied the manufacturing industry’s lean theory to propose a lean prebid planning model (LPPM) for construction contractors. The LPPM can significantly eliminate the main types of waste in construction projects because it effectively combines three important concepts in the manufactureing industry: transformation, workflow, and value generation. This model includes seven arrangement steps, which are described systematically to help contractors with real-world applications. A case study was …

Go to article

Experimental Study On The Motions Of A Mooring Ship In Mixed Waves, Xian-Ying Shi, Yang Yang, Ning-Chuan Zhang, Yu-Xin Huang Aug 2013

Experimental Study On The Motions Of A Mooring Ship In Mixed Waves, Xian-Ying Shi, Yang Yang, Ning-Chuan Zhang, Yu-Xin Huang

Journal of Marine Science and Technology–Taiwan

By employing the method of bimodal spectral simulations, a series of experiments were performed on a 266,000 m3 LNG ship moored to an island berth in mixed waves. In the physical model experiments, a special effort was made to investigate how changing wave conditions affect the motion responses of the mooring ship in mixed waves. Therefore, this paper mainly engages in the analysis of such effects resulted from wave condition changes of mixed waves from such perspectives as the distribution of high- and low-frequency energy, the periodic changes of low-frequency swells, the wave-height changes of low-frequency swells, and the wave-height …

Go to article

Comparison Of Different Wind Stress Effects On Sst And Sss In The East China Sea Region, Hung-Jen Lee, Shih-Jen Huang, Shenn-Yu Chao, Kon-Kee Liu Aug 2013

Comparison Of Different Wind Stress Effects On Sst And Sss In The East China Sea Region, Hung-Jen Lee, Shih-Jen Huang, Shenn-Yu Chao, Kon-Kee Liu

Journal of Marine Science and Technology–Taiwan

Ocean circulations closely associated with the changes of wind system are investigated using a three-dimensional tidecirculated coupling model. Based on the coupling model, we apply different wind datasets, to some extent reflecting wind system variations associated with global climate change, but constant monthly temperature and salinity fields to assess the effect of differing wind strength stresses in the East China Sea region, leading to significant influences on hydrographic fields. In the model based on the Hellman-Rosenstein wind dataset, more distant from the mouth of the Changjiang River (Yangtze River), the Yellow Sea Warm Current strengthens because of the wind stress; …

Go to article

A Real Case Study On The State Of Corrosion Of The Spanish Boats, José A Orosa, Juan José Galán, Mar Toledano Aug 2013

A Real Case Study On The State Of Corrosion Of The Spanish Boats, José A Orosa, Juan José Galán, Mar Toledano

Journal of Marine Science and Technology–Taiwan

In this real case study we analyze various corrosion problems encountered in Spanish fleets and present possible solutions. As a first step, we developed a statistical analysis of the north Mediterranean Sea fleets to define the age of the vessels, hull construction material and main activities involved. As a result, different corrosion problems were identified as well as solutions like paint, sacrificial anodes and impressed currents, and of course, improved design. Generally, we can state that, according to the results obtained, a series of incidents have increased the repair and maintenance costs of the vessels in the area under study

Go to article

Shape Optimization Of One-Chamber Perforated Mufflers Filled With Wool Using Simulated Annealing, Min-Chie Chiu Aug 2013

Shape Optimization Of One-Chamber Perforated Mufflers Filled With Wool Using Simulated Annealing, Min-Chie Chiu

Journal of Marine Science and Technology–Taiwan

Research on dissipative and reactive mufflers has been addressed. However, the acoustical performance ―sound transmission loss (STL)― of mufflers within a constrained space is often insufficient. In this paper, to improve the acoustical efficiency, a one-chamber perforated muffler filled with sound absorbing wool optimized by using simulated annealing (SA) in conjunction with the numerical decoupling technique is presented. A numerical case in eliminating a broadband noise is also introduced. To verify the reliability of SA optimization, optimal noise abatements for the pure tone are exemplified. Before the SA operation can be carried out, the accuracy of the mathematical models has …

Go to article

Model Reference Robust Control For Marine Propulsion Systems With Model Uncertainty Caused By Hull Deformation, Zhixiong Li, Xinping Yan, Li Qin, Chengqing Yuan, Zhongxiao Peng Aug 2013

Model Reference Robust Control For Marine Propulsion Systems With Model Uncertainty Caused By Hull Deformation, Zhixiong Li, Xinping Yan, Li Qin, Chengqing Yuan, Zhongxiao Peng

Journal of Marine Science and Technology–Taiwan

A marine propulsion system can be strongly coupled with the hull deformation in a large-scale ship. The interaction of this coupling dynamics increases the nonlinearity and complexity of the control model. Traditional control method based on the empirical PID (proportion-integration-differentiation) parameters has difficulty in dealing with the model uncertainty caused by the hull deflection. However, up to date, limited work has been done to address the model uncertainty problem of the marine propulsion system. It is therefore imperative to develop feasible and effective control systems that take the model uncertainty into account. In this study, a new method based on …

Go to article

The Application Of The Genetic Adaptive Neural Network In Landslide Disaster Assessment, Jing-Wen Chen, Yung-Sheng Chue, Yie-Ruey Chen Aug 2013

The Application Of The Genetic Adaptive Neural Network In Landslide Disaster Assessment, Jing-Wen Chen, Yung-Sheng Chue, Yie-Ruey Chen

Journal of Marine Science and Technology–Taiwan

This study applied the Genetic Adaptive Neural Network (GANN) structure to satellite image classification and the assessment of landslide disaster. First, the study conducted quantitative analysis of the various factors of slope development and natural environmental hazards in some parts of the catchment areas of the Laonong River in Southern Taiwan. Meanwhile, using the weighting ratios of various disaster causing factors inferred from the best structure of GANN, this study explored the degree of slope land disturbance. Then, this study incorporated the relationship between rainfall and landslides to draw a landslide potential map using the discriminant analysis approach combined with …

Go to article

Model Simulation Of Asian Dust And Iron Depositions Over The East Asian Marginal Seas, Fujung Tsai Aug 2013

Model Simulation Of Asian Dust And Iron Depositions Over The East Asian Marginal Seas, Fujung Tsai

Journal of Marine Science and Technology–Taiwan

This study applies a dust model to investigate Asian dust and iron depositions on the East Asian marginal sea during the months of the northeasterly monsoon from November to May, when dust events are often observed. Simulated dry and wet depositions of dust are compared with measurements obtained from Taipei, Taiwan. According to the model simulation, higher concentrations of atmospheric dust occur from March to May over East Asia, resulting in greater dry and wet deposition fluxes of dust and iron within these months than other months. The monthly averaged dry and wet deposition fluxes of iron are 0.6 and …

Go to article

Prediction Of Bridge Pier Scour Using Genetic Programming, Chuan-Yi Wang, Han-Peng Shih, Jian-Hao Hong, Rajkumar V Raikar Aug 2013

Prediction Of Bridge Pier Scour Using Genetic Programming, Chuan-Yi Wang, Han-Peng Shih, Jian-Hao Hong, Rajkumar V Raikar

Journal of Marine Science and Technology–Taiwan

This paper presents the use of genetic programming (GP) as a tool to predict pier scour depths based on clear-water conditions of laboratory measurements by past researchers. Four main dimensionless parameterspier width, approaching flow depth, threshold flow velocity, and channel open-ratio are considered for predicting the scour depth. The performance of the GP equation is verified by comparing the results with those obtained by empirical equations. It is found that the scour depth at bridge piers can be efficiently predicted using the GP model. The advantage of the GP model is confirmed by comparing the GP results of scour depths …

Go to article

Analysis Of Intervertebral Disc Degeneration Testing Method, David Williams, Dr. Anton Bowden Aug 2013

Analysis Of Intervertebral Disc Degeneration Testing Method, David Williams, Dr. Anton Bowden

Journal of Undergraduate Research

This ORCA research project has focused on the determination of the effects of the order of the mechanical tests on the response of an intervertebral disc. We hypothesized that the order of the mechanical tests may influence the rate of diffusion of the Trypsin throughout the disc, affecting the biomechanical response. We have planned to determine the magnitude of this influence by using statistical techniques to analyze the data acquired. Virtually all of us (80 to 90 percent) will experience back pain in our lives. Low back pain is the leading cause of missed work days. The estimated economic impact …

Go to article

Influence Of Airway Liquid Hydration And Properties On Human Vocal Fold Vibration, Preston Murray, Dr. Scott Thomson Aug 2013

Influence Of Airway Liquid Hydration And Properties On Human Vocal Fold Vibration, Preston Murray, Dr. Scott Thomson

Journal of Undergraduate Research

The purpose of this research project was to identify a fluid that has similar properties as the airway surface liquid (ASL) that covers vocal folds, and then apply it to a vibrating synthetic vocal fold model to measure its effects.

Go to article

Parametric Optimization Of Wind Turbine Blades, Brycee Mcewen, Dr. Steven Gorrell Aug 2013

Parametric Optimization Of Wind Turbine Blades, Brycee Mcewen, Dr. Steven Gorrell

Journal of Undergraduate Research

With ever increasing concerns about the production of greenhouse gases from burning fossil fuels, more and more emphasis is being placed on researching and developing alternative and renewable energy resources. One renewable energy source that has the potential to compete with conventional fossil fuels, is wind energy. In order for wind energy to be competitive, it is necessary to make improvements in both aerodynamic and structural properties of wind turbines.

Go to article

Piezoresistivity In Nickel Nanostrand Composite Materials As Studied By Three-Dimensional Reconstruction On Focused Ion Beam Serial-Sections, Oliver Johnson, Dr. David Fullwood Aug 2013

Piezoresistivity In Nickel Nanostrand Composite Materials As Studied By Three-Dimensional Reconstruction On Focused Ion Beam Serial-Sections, Oliver Johnson, Dr. David Fullwood

Journal of Undergraduate Research

The development of a large-strain sensor technology will open doors for improved engineering design and scientific research in many fields. Such a technology would allow for advances in biomechanical engineering, e.g., prosthetic limb and artificial organ design. Additionally this kind of sensor technology could be used for tactile robotics and even structural health monitoring, such as in wind turbines or architectural structures. Our research group has developed a unique Silicone/Nickel Nanostrand/Nickel Coated Carbon Fiber (Si/NiNs/NCCF) nanocomposite that can measure strains of up to 50% elongation. The purpose of this project was to investigate how the nano-scale structure of this material …

Go to article

Autonomous Soaring Using Real-Time Wind Estimation, Mark J. Cutler, Dr. Timothy Mclain Aug 2013

Autonomous Soaring Using Real-Time Wind Estimation, Mark J. Cutler, Dr. Timothy Mclain

Journal of Undergraduate Research

Small unmanned aerial vehicles (UAVs) are obtaining increasing utilization in many applications. Their small size (0.5-4m wingspan) allows them to fly close to the ground, providing useful observation and tracking data. This small size, however, comes at the expense of flight time. As UAV size decreases, the amount of stored energy (electrical or chemical) the UAV is able to carry also decreases. If long flight times are to be obtained with a small UAV, other energy sources must be exploited. Naturally occurring atmospheric phenomena provide one such potential energy source.

Go to article

Dynamic Loading On Horizontal Axis Wind Turbine Blades, Christopher Brinkerhoff, Julie Vanderhoff Aug 2013

Dynamic Loading On Horizontal Axis Wind Turbine Blades, Christopher Brinkerhoff, Julie Vanderhoff

Journal of Undergraduate Research

Currently, there is much interest involving technologies dealing with clean and renewable energy sources. The current goal in the United States is to produce 20% of its electrical needs by wind power by the year 2030. Wind energy is seen as a viable option for further research because of its low carbon footprint and virtually limitless supply of wind, but in order for it to be economically viable, there are certain aspects of wind technology that need improvement.

Go to article

Economic And Environmental Justification Of A Thermoelectric Waste Heat Recovery System, John Christiansen, Dr. Matthew Jones Aug 2013

Economic And Environmental Justification Of A Thermoelectric Waste Heat Recovery System, John Christiansen, Dr. Matthew Jones

Journal of Undergraduate Research

In recent years, the concepts of energy, energy production, effects of energy consumption on the environment, and sustainable development have become increasingly significant as members of society become more aware of their level of energy consumption. However, in energy production for home, commercial, or industrial use, up to 60 percent of the chemical energy potential (in the form of fossil or other fuels) is lost in the form of waste heat. In other words, when fossil or other fuels are burned, only 30 to 40 percent of the potential chemical energy is actually harnessed and converted into useful electricity! This …

Go to article

Third World Water Filtration System Implementation, Christopher Welton, Perry Carter Aug 2013

Third World Water Filtration System Implementation, Christopher Welton, Perry Carter

Journal of Undergraduate Research

Approximately 70 million people in rural India do not have access to clean water. Chemicals such as cesium, arsenic, and others contaminate India’s drinking water, rendering it unsafe. Biological contaminates pose increased health risks to those drinking the water. If a water source is bad, large populations need to relocate to find a better source of water. Creating an economic water filtration system capable of being obtained through a micro-loan is beginning alleviate this problem. By creating an affordable and quality system, clean water is becoming a reality for the world’s poor, especially in Third World countries. Through my efforts …

Go to article

Bridging The Gap Between Simulation And Experiment With Multi-State Protein Folding, Jacob Lewis, Dr. Thomas Knotts Aug 2013

Bridging The Gap Between Simulation And Experiment With Multi-State Protein Folding, Jacob Lewis, Dr. Thomas Knotts

Journal of Undergraduate Research

Proteins are made up of extremely long chains of amino acids. Depending on it constituent amino acids, proteins fold in many 3-dimensional patterns to facilitate various biochemical processes such as catalyzing chemical reactions which allow us to live. How proteins fold is thought to be the “holy grail” of biochemistry research and, as of yet, no one has been able to predict exactly how a given sequence of amino acids will fold a priori. Protein folding has been probed in experiment and simulated on computers, but there are discrepancies between the two methods. Naturally, the experimental results are what computer …

Go to article

Analysis Of Piranha Etching In The Microfabrication Of Hollow-Core Optical Waveguides, Jared Keeley, Dr. Aaron Hawkins Aug 2013

Analysis Of Piranha Etching In The Microfabrication Of Hollow-Core Optical Waveguides, Jared Keeley, Dr. Aaron Hawkins

Journal of Undergraduate Research

In the field of micro-electromechanical systems (MEMS) and micro-opto-electromechanical systems (MOEMS) fabrication, photoresists are used to form 3D structures on a scale of micro- or even nanometers. This is necessary to create the microelectronics used in many devices. One structure that photoresist can be used to create is a hollow-core optical waveguide. To complete the waveguide something must be used to remove the photoresist from the core. Piranha is a mixture of hydrogen peroxide (H2O2) and sulfuric acid (H2SO4) that can be used to remove photoresist. One goal of my ORCA project was to analyze piranha’s effectiveness in fabricating hollow-core …

Go to article

Post-Translational Modification In Cell-Free Protein Synthesis, Anna Katz, Dr. Brad Bundy Aug 2013

Post-Translational Modification In Cell-Free Protein Synthesis, Anna Katz, Dr. Brad Bundy

Journal of Undergraduate Research

The purpose of this project was to examine the phenomenon of eukaryotic myristoylation in a prokaryotic cell-free environment. Basically the idea is that eukaryotic cells such as those within humans have a more robust system for synthesizing protein but it is cheaper, faster, and more easily controlled to synthesize protein in bacteria cells. The problem, then, with using bacteria is that it lacks the ability to perform such functions as post-translational modification; in other words, once the protein has been created through RNA transcription separate enzymes add functional groups to the protein. One such modification is myristoylation, which uses the …

Go to article

High Temperature Water Gas Shift Catalyst Kinetic Evaluation, Rupak Bajagain, Dr. Morris Argyle Aug 2013

High Temperature Water Gas Shift Catalyst Kinetic Evaluation, Rupak Bajagain, Dr. Morris Argyle

Journal of Undergraduate Research

The purpose of this project was to develop water gas shift catalysts that are more stable and active than the existing ones. Stable catalysts last longer and are more efficient, which is important to economics and to gain widespread application. Currently the demand for hydrogen as a fuel is low but in the future there is a high potential that hydrogen could be important in world energy. This project was performed by a group of undergraduate and graduate students from BYU. Most of the work in the project was performed by group members. The report focuses mainly on the tasks …

Go to article

Effect Of Variability In Concrete Cover On Concrete Bridge Deck Service Life, Jeffrey Hoki, Dr. W. Spencer Guthrie Aug 2013

Effect Of Variability In Concrete Cover On Concrete Bridge Deck Service Life, Jeffrey Hoki, Dr. W. Spencer Guthrie

Journal of Undergraduate Research

Before reliable data could be gathered, proper procedures for using a covermeter needed to be established. The American Society for Testing and Materials (ASTM) does not currently have a standard for testing rebar cover depth by means of an electromagnetic covermeter. Therefore, the only protocol for testing available to the tester originates from the manufacturer of each individual covermeter. This research focused on the development of a standardized protocol for covermeter testing to be used within the Long Term Bridge Performance (LTBP) program. The Standardization of covermeter usage will increase the reliability of results gathered from all teams within the …

Go to article

High-Speed Full-Spectrum Interrogation Of Fiber Bragg Gratings For Composite Laminate Sensing, Tyrie Vella, Dr. Richard Selfridge Aug 2013

High-Speed Full-Spectrum Interrogation Of Fiber Bragg Gratings For Composite Laminate Sensing, Tyrie Vella, Dr. Richard Selfridge

Journal of Undergraduate Research

Fiber Bragg Grating (FBG) sensors are specialized optical fibers that can be used for detecting changes in strain. Under normal conditions, when a broadband spectrum of light is transmitted through the fiber, a narrow band of light is reflected by the sensor. When an FBG is embedded into a composite material and the material is placed under stress, the wavelength at which the reflected band is centered shifts in proportion to the stress, allowing the strain to be measured. By monitoring the sensor during repeated impacts on the material, structural damage can be discerned and the material could be replaced …

Go to article

First Prev Next Last