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2008

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Articles 2881 - 2910 of 4190

Full-Text Articles in Engineering

Simulation Of A Circulating Fluidised Bed Biomass Gasifier Using Aspen Plus: A Performance Analysis, Wayne Doherty, Anthony Reynolds, David Kennedy Jan 2008

Simulation Of A Circulating Fluidised Bed Biomass Gasifier Using Aspen Plus: A Performance Analysis, Wayne Doherty, Anthony Reynolds, David Kennedy

Conference Papers

In the near future biomass gasification is likely to play an important role in energy production and conversion. Its application has great potential in the context of climate change mitigation, increasing efficiency and energy security. Atmospheric circulating fluidised bed (CFB) technology was selected for the current study. An original computer simulation model of a CFB biomass gasifier was developed using ASPEN Plus (Advanced System for Process ENgineering Plus). It is based on Gibbs free energy minimisation and the restricted equilibrium method was used to calibrate it against experimental data. This was achieved by specifying the temperature approach for the gasification …

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Reduction Of Ground-Plane-Dependent Effects On Microstrip-Fed Printed Rectangular Monopoles, Matthias John, Jonathan Evans, Max Ammann, J. C. Modro, Z. N. Chen Jan 2008

Reduction Of Ground-Plane-Dependent Effects On Microstrip-Fed Printed Rectangular Monopoles, Matthias John, Jonathan Evans, Max Ammann, J. C. Modro, Z. N. Chen

Articles

Methods to mitigate the strong dependence of impedance bandwidth on the ground- plane size for a rectangular printed planar monopole is described. It is shown that the bandwidth limitation may be overcome by introducing feed-line asymmetry, which alters the purity and the Q of the higher frequency modes and by ground-plane augmentation, which effects the lower frequency modes. A method of extending the ground plane without increasing the overall antenna size is shown to improve both the bandwidth and gain and also to enable the use of significantly smaller ground planes. The effects of these techniques on radiation pattern are …

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Violin Timbre Space Features, Jane Charles, Derry Fitzgerald, Eugene Coyle Jan 2008

Violin Timbre Space Features, Jane Charles, Derry Fitzgerald, Eugene Coyle

Conference papers

Signal processing techniques, from which the quality of a violinist's playing can be assessed by a computer are presented in this paper

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Analogical Reasoning In The Engineering Design Process And Technology Education Applications, Jenny Daugherty, Nathan Mentzer Jan 2008

Analogical Reasoning In The Engineering Design Process And Technology Education Applications, Jenny Daugherty, Nathan Mentzer

Publications

This synthesis paper discusses the research exploring analogical reasoning, the role of analogies in the engineering design process, and educational applications for analogical reasoning. Researchers have discovered that analogical reasoning is often a fundamental cognitive tool in design problem solving. Regarding the possible role of analogical reasoning in the context of technology education; analogies may be a useful tool to develop student’s design skills, teach abstract or complex concepts, and build students’ analogical reasoning skills for general problem solving. The positive and negative educational implications of analogical reasoning being explored by researchers are also discussed.

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Resources: Handheld Computing Devices, Cameron Denson Jan 2008

Resources: Handheld Computing Devices, Cameron Denson

Publications

The article features a valuable resource to aid teachers in their effort to satisfy the need to implement modern instructional technology and their students' need to access green technology. It states that handheld computing devices are currently being widely used in many classrooms and technology savvy educators can manifest to the benefits of these data-collection systems. It believes that handheld units can offer students with an all-inclusive technological device that caters to all learners.

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Engineering Student Outcomes For Grades 9 - 12, Vincent W. Childress, Craig Rhodes Jan 2008

Engineering Student Outcomes For Grades 9 - 12, Vincent W. Childress, Craig Rhodes

Publications

The article focuses on a study by Dearing and Daughtry about postsecondary engineering education. The study used a modified Delphi technique that they conducted with technology teachers, technology teacher educators, and engineering educators to identify engineering outcomes for high school pre-engineering students. The purpose of the study was to identify those concepts that are necessary to teach high school students in order to prepare them for postsecondary engineering education, while preserving the mission of teaching technological literacy.

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Quality And Characteristics Of Recent Research In Technology Education, Scott D. Johnson, Jenny Daugherty Jan 2008

Quality And Characteristics Of Recent Research In Technology Education, Scott D. Johnson, Jenny Daugherty

Publications

The focus of research in technology education has evolved throughout its history as the field changed from industrial arts to technology education (Spencer & Rogers, 2006). With the move to technology education, the field has begun to broaden its focus to better understand the teaching, learning, curriculum, and policy implications of preparing the next generation of technological thinkers. Although a complete “paradigm shift” may not have occurred completely within all technology-oriented programs (Sanders, 2001), the current emphasis on engineering within technology education indicates a need to examine and assess the status of technology education research over the past ten years …

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Resources: E-Book Readers, Daniel Brenner, Todd R. Kelley Jan 2008

Resources: E-Book Readers, Daniel Brenner, Todd R. Kelley

Publications

The article provides information on the resources of electronic book (e-book) reader. It cites that an e-book reader is a device where people can download, store, and read printed materials. However, e-book readers are not applicable in educational setting because textbooks are not yet available for download. There are funding programs for e-books readers in schools emerged like Target Early Childhood Reading Grants, HP Technology for Teaching Grant Initiative, and EDS Technology Grant Program.

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Resources: Getting There - Space, Todd R. Kelley Jan 2008

Resources: Getting There - Space, Todd R. Kelley

Publications

The article presents a school activity about transportation concepts using the DVD "Black Sky: The Race for Space & Winning the X-Prize." The article describes the video as a good resource to explore novel ideas in space travel with students. It suggests that the video inspires students to learn more about space transportation and the science and technology of modern rocketry.

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Characterization Of Changes In Hyaluronan Following Epidermal Barrier Injury In An Organotypic Model, Gati Ajani Jan 2008

Characterization Of Changes In Hyaluronan Following Epidermal Barrier Injury In An Organotypic Model, Gati Ajani

ETD Archive

The stratum corneum, the outermost layer of the epidermis of skin, provides a functional permeability barrier that is essential for our survival and must be rapidly repaired after injury. Of interest to us, a ubiquitous matrix molecule called hyaluronan (HA) has come to the forefront in wound healing research because it is induced after epidermal injury and may be crucial for barrier repair. This thesis examines the role of HA during recovery from the most fundamental form of skin injury, i.e. selective damage to the stratum corneum. The overall question is whether this form of stratum corneum injury can lead …

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Novel Antifreeze Protein Constructs For Improved Activity, Ozge Can Jan 2008

Novel Antifreeze Protein Constructs For Improved Activity, Ozge Can

ETD Archive

Many organisms are exposed to subzero temperatures in nature and can survive these temperatures by the effect of antifreeze proteins (AFPs), which inhibit ice crystal growth and change the morphology of ice crystals. Although the effects of these proteins, such as recrystallization inhibition, ice growth inhibition, and crystal habit changes, are known, a conclusive description of the protein-ice crystal interaction including interaction energy, surface coverage, and lifetime of adsorbate has been elusive. In this study, different antifreeze protein constructs are designed and expressed such that they can be conjugated to polymers to increase the thermal hysteresis activity especially at low …

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Fabrication Of Nanostructured Metals And Their Hydrogen Storage Properties, Asli Ertan Jan 2008

Fabrication Of Nanostructured Metals And Their Hydrogen Storage Properties, Asli Ertan

ETD Archive

Searching for new energy sources is highly desirable for the next generations when rapidly changing factors are considered such as population, increasing pollution and exhaustion of fossil fuels. Hence, there is a need for clean, safe and efficient energy carriers or forms of energy that can be transported to the end user. One of these energy carriers is electricity which has been used widely and can be produced from various sources. However, its production from fossil fuels contributes to pollution. On the other hand hydrogen, due to its abundance, light weight, low mass density, high energy density and non-polluting nature …

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A Hybrid Reconfigurable Solar And Wind Energy System, Sagar A. Gadkari Jan 2008

A Hybrid Reconfigurable Solar And Wind Energy System, Sagar A. Gadkari

ETD Archive

We study the feasibility of a novel hybrid solar-wind hybrid system that shares most of its infrastructure and components. During periods of clear sunny days the system will generate electricity from the sun using a parabolic concentrator. The concentrator is formed by individual mirror elements and focuses the light onto high intensity vertical multi-junction (VMJ) cells. During periods of high wind speeds and at night, the same concentrator setup will be reconfigured to channel the wind into a wind turbine which will be used to harness wind energy. In this study we report on the feasibility of this type of …

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Effective Area And Effective Volume Calculations For Ceramic Test Specimens, Rahul Jain Jan 2008

Effective Area And Effective Volume Calculations For Ceramic Test Specimens, Rahul Jain

ETD Archive

Calculation of effective volume and/or effective area is a key step in estimating reliability of ceramic component life cycle. Most common tests performed to assess the strength and reliability of components made from ceramics are bend bar specimens tested in three-point and four-point flexure, C-ring and O-ring specimen under diametral compressive or tensile loads and biaxial ring-on-ring specimens. ASTM closed form solutions for the effective volume and area exists for these specimen geometries which are based on classical theories with underlying assumptions. In general the closed form expressions are valid for limited specimen geometry bounds. An alternative numerical approach has …

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Greenometer-7: A Tool To Assess The Sustainability Of A Building's Life Cylce At The Conceptual Design Phase, Muhammad Musa Mer'eb Jan 2008

Greenometer-7: A Tool To Assess The Sustainability Of A Building's Life Cylce At The Conceptual Design Phase, Muhammad Musa Mer'eb

ETD Archive

This study presents a tool that has been developed to measure and subsequently improve the sustainability performance of a building over its entire life-cycle while still at the conceptual design stage. This forecasting tool is called GREENOMETER-7. GREENOMETER-7 is a LCA tool and it evaluates the projected building at two levels: micro- and macro-assessment. The micro-assessment level provides in-depth analysis of the building products, components, and operations however, the macro-assessment level measures the sustainability performance of the building as a whole and covers areas that are not applicable at the product or component level. Both levels consist of categories and …

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Mems (Micro-Electro-Mechanical-Systems) Based Microfluidic Platforms For Magnetic Cell Separation, Pulak Nath Jan 2008

Mems (Micro-Electro-Mechanical-Systems) Based Microfluidic Platforms For Magnetic Cell Separation, Pulak Nath

ETD Archive

Microfluidic platforms for magnetic cell separation were developed and investigated for isolation of magnetic particles and magnetically tagged cells from a fluidic sample. Two types of magnetic separation platforms were considered: an Isodynamic Open Gradient Magnetic Sorter (OGMS) and a multistage bio-ferrograph. Miniaturized magnets were designed using magnetostatic simulation software, microfluidic channels were fabricated using microfabrication technology and magnetic separation was investigated using video microscopy and digital image processing. The isodynamic OGMS consisted of an external magnetic circuit and a microfabricated channel (biochip) with embedded magnetic elements. The biochip is placed inside the magnetic field of the external circuit to …

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Bio-Signal Analysis In Fatigue And Cancer Related Fatigue;Weakening Of Corticomuscular Functional Coupling, Qi Yang Jan 2008

Bio-Signal Analysis In Fatigue And Cancer Related Fatigue;Weakening Of Corticomuscular Functional Coupling, Qi Yang

ETD Archive

Fatigue is a common experience that reduces productivity and increases chance of injury, and has been reported as one of most common symptoms with greatest impact on quality-of-life parameters in cancer patients. Neural mechanisms behind fatigue and cancer related fatigue (CRF) are not well known. Recent research has shown dissociation between changes in brain and muscle signals during voluntary muscle fatigue, which may suggest weakening of functional corticomuscular coupling (fCMC). However, this weakening of brain-muscle coupling has never been directly evaluated. More important information could be gained if fCMC is directly detected during fatigue because a voluntary muscle contraction depends …

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A Novel Cardiac Pacing Paradigm For Atrial Fibrillation And Heart Failure Patients, George Emanuel Yanulis Jan 2008

A Novel Cardiac Pacing Paradigm For Atrial Fibrillation And Heart Failure Patients, George Emanuel Yanulis

ETD Archive

It has been estimated that 4.6 million persons have heart failure, and 400,000 to 700,000 new cases develop each year and the U.S. Hospital discharges for HF rose from 399,000 in 1979 to 1,099,000 in 2004 according to the National Hospital Discharge Survey. Atrial fibrillation is the most common sustained cardiac arrhythmia in the United States. Recent studies have demonstrated that ventricular rate control is a viable treatment strategy for patients in atrial fibrillation. In a number of cases, despite the electrical resynchronization of the ventricles using biventricular pacing (cardiac resynchronization therapy), heart failure patients in sinus rhythm do not …

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Biocompatibility Of Osteoblast Cells On Titanium Implants, Dilip Ayyala Somayajula Jan 2008

Biocompatibility Of Osteoblast Cells On Titanium Implants, Dilip Ayyala Somayajula

ETD Archive

Adhesion and proliferation of UMR 106-01 osteoblast cells were studied on various surface modified titanium materials such as polished, sandblasted, anodized and alkaline treated. Anodization of polished surface in Hydrofluoric acid developed nano-tubes, while NaOH treatment produced spongy microporous morphology. Test samples were coated with non-adhesive protein bovine serum albumin and compared with fibronectin coated specimens. The adhesion study lasted for 4 hrs, where osteoblast cells were cultured in serum free medium. Polished titanium, anodized titanium and NaOH titanium have shown similar percentages of cell adherence. The proliferation study lasted for 48 hrs, where cells were initially allowed to adhere …

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Convolutional Coded Generalized Direct Sequence Spread Spectrum, Madan Venn Jan 2008

Convolutional Coded Generalized Direct Sequence Spread Spectrum, Madan Venn

ETD Archive

In this thesis we investigate the worst-case performance of coded ordinary and coded generalized direct sequence spread spectrum (DSSS) systems in a communication channel corrupted by an unknown and arbitrary interfering signal of bounded power. We consider convolutional codes with Viterbi decoding in order to compare the performance of coded ordinary and coded generalized DSSS systems. For the generalized DSSS system, we use a pulse stream of +1,-1 and 0 as the spreading sequence, which is different from ordinary DSSS system which uses the typical sequence with pulse values of +1 and -1. A C program for performing Monte-Carlo simulations …

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Comparison Of Methods For Developing Estimated Parameter̄X Control Charts Propsed By Nedumaran & Pignatiello, Albers & Kallenberg And Tsai Et Al., Ozlem Temiz Jan 2008

Comparison Of Methods For Developing Estimated Parameter̄X Control Charts Propsed By Nedumaran & Pignatiello, Albers & Kallenberg And Tsai Et Al., Ozlem Temiz

ETD Archive

The subject of this thesis is the comparison of the development method used to determine the value of Xbar control chart limits when the underlying process parameters are unknown and must be estimated from data obtained from a Phase I historical samples. I propose in the research for this thesis to compare these three proposed methods in detail comparing their performance by developing empirical probability of signal distributions for both in-control and out-of-control situations. Generation of these distributions will be accomplished through discrete simulation. The final result will consist of recommendations concerning the best of the methods to use in …

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Road Surface Condition Detection And Identification And Vehicle Anti-Skid Control, Maosheng Ye Jan 2008

Road Surface Condition Detection And Identification And Vehicle Anti-Skid Control, Maosheng Ye

ETD Archive

Road surface condition is greatly dependent on the surface's friction coefficient. The abrupt change of the coefficient results in variation of wheel slip which likely leads to vehicle instability. Vehicle steering model and the dynamic equations for four-wheel drive vehicle is developed. A new observer, called Extended State Observer (ESO) is used to estimate the longitudinal velocity, lateral velocity and yaw rate, and more importantly an additional quantity known as system dynamics. A trained neural network was employed to help determine the friction coefficient. Fuzzy logic was employed to quickly detect the change of road surface condition and further classify …

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A Kinematics Based Tolerance Analysis Of Mechanisms, Shahrbanoo Biabnavi Farkhondeh Jan 2008

A Kinematics Based Tolerance Analysis Of Mechanisms, Shahrbanoo Biabnavi Farkhondeh

ETD Archive

A kinematic based tolerance analysis of mechanisms is presented in this thesis. It is shown that standard kinematic analysis can be used for obtaining closed-form explicit formulations for tolerance analysis of mechanisms. It is proposed that the manufacturing tolerances are accounted for by incorporating fictitious sliding members in the rigid links, thereby allowing them to either "grow" or "shrink" along the lines of their pin connections. The virtual expansions or contractions of these fictitious sliders are captured in the kinematic equations by taking the differentials of the magnitudes of the vectors that define the length of rigid links having dimensional …

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Effect Of Axial Oscillation On Performance Of Hydrodynamic Journal Bearings, Thomas Wirsing Jan 2008

Effect Of Axial Oscillation On Performance Of Hydrodynamic Journal Bearings, Thomas Wirsing

ETD Archive

The hydrodynamic coefficients of a journal bearing set with the bearing subjected to axial oscillation are determined in this work. The Navier-Stokes equations were used to account for the axial component of the relative motion between the journal and the bearing. Numerical solution of the Navier-Stokes equations yielded the pressure distribution within the cavity of the bearing. This pressure distribution was then integrated over the surface of the bearing to obtain the two orthogonal force components. The derivatives of these force components were then taken with respect to the displacement and velocity of the journal that are co-linear with these …

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Modeling Of Transient Thrust Of A Two Phase Propellant Tank, Karthik Mellechervu Jan 2008

Modeling Of Transient Thrust Of A Two Phase Propellant Tank, Karthik Mellechervu

ETD Archive

This thesis develops a model to predict various time-varying quantities associated with the evacuation of a pressurized container through a nozzle. The container is part of a satellite propulsion prototype used to study attitude control. Variables of interest include the thrust and mass of fluid in the tank as functions of time. A mathematical model based on transient expressions for mass and energy conservation is derived for a two-phase system representative of the conditions of the fluid inside the tank

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Multiplexed Control Of Smart Structure Using Piezoelectric Actuators, Kumar S. Nale Jan 2008

Multiplexed Control Of Smart Structure Using Piezoelectric Actuators, Kumar S. Nale

ETD Archive

Active control of smart structures containing a large number of actuators and sensors presents a tradeoff between increased system performance and the cost and bulk of the required hardware and computational resources. A technique called multiplexed control offers advantages when software and hardware resources are scarce and performance specifications call for a large number of actuators and sensors. In structural control applications, in particular those using smart materials, it is often desirable to increase the number of actuators to enhance controllability.The focus of this research is to demonstrate real-time multiplexing on the hardware side of the actively controlled structure. Multiplexing …

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Development Of Effective Balancing Procedure For Ct Scanner, Jeremy David Pettinato Jan 2008

Development Of Effective Balancing Procedure For Ct Scanner, Jeremy David Pettinato

ETD Archive

Since the beginning of medical organizations, engineering departments have introduced new innovative ideas and designs to advance image quality. In the case of a CT scanner, one of the largest and most cost effective ways to achieve superior image quality is through a well balanced rotating array. The focus of this thesis is the development of a balancing procedure which will effectively balance a CT scanner rotating array. Rigid rotor (dynamic) balancing techniques are utilized in order to balance the Philips CT scanner rotor. Upon completion of the dynamic balancing of the CT scanner rotor a new an innovative way …

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Health Monitoring Of Cracked Rotor Systems Using External Excitation Techniques, Adam C. Wróblewski Jan 2008

Health Monitoring Of Cracked Rotor Systems Using External Excitation Techniques, Adam C. Wróblewski

ETD Archive

Cracked rotors present a significant safety and loss hazard in nearly every application of modern turbomachinery. This thesis focuses on the health monitoring, modeling, and analysis of machines with transverse breathing cracks, which open and close due to the self-weight of the rotor. After considering the modeling of cracked rotors, the thesis investigates an active structural health monitoring approach, focusing on the application of an active magnetic actuator to apply a specially designed external force excitation to the rotating shaft. Extensive experimental data has been collected and analyzed utilizing advanced diagnostic techniques. The presented results demonstrate that the use of …

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A Sensor Network System For Monitoring Short-Term Construction Work Zones, Manohar Bathula Jan 2008

A Sensor Network System For Monitoring Short-Term Construction Work Zones, Manohar Bathula

ETD Archive

Safety hazards encountered near construction work zones are high, both in number and in the kind. There is a need to monitor traffic in such construction zones in order to improve driver and vehicle safetyIn the past traffic monitoring systems were built with high cost equipment such as inductive plates, video cameras etc. These solutions are too cost{prohibitive and invasive to be used in the large. Wireless sensor networks provide an opportunity space that can be used to address this problem. This thesis specifically targets temporary or short-term construction work zones. We present the design and implementation of a sensor …

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A Wrapper-Based Approach To Sustained Time Synchronization In Wireless Sensor Networks, Dheeraj Reddy Bheemidi Jan 2008

A Wrapper-Based Approach To Sustained Time Synchronization In Wireless Sensor Networks, Dheeraj Reddy Bheemidi

ETD Archive

Time synchronization is an important service for wireless sensor network applications. Nodes in the network stay synchronized by exchanging periodic messages that carry local timestamps. Several algorithms have been proposed in the literature that are suited to different kinds of application scenarios. A common problem across these time synchronization algorithms is that the energy cost of message exchange is high. In fact, the cost of radio communication far outstrips the cost of performing local operations on the processor. If the message exchanges were stopped, nodes will fall out of sync, and may no longer be able to meet application requirements. …

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