Engineering Commons^™

Effects Of Supplemental Viscous Damping On Seismic Response Of Asymmetric-Plan Systems, Rakesh K. Goel

Civil and Environmental Engineering

Coupling between lateral and torsional motions may lead to much larger edge deformations in asymmetric‐plan systems compared to systems with a symmetric plan. Supplemental viscous damping has been found to be effective in reducing deformations in the symmetric‐plan system. This investigation examined how supplemental damping affects the edge deformations in asymmetric‐plan systems. First, the parameters that characterize supplemental viscous damping and its plan‐wise distribution were identified, and then the effects of these parameters on edge deformations were investigated. It was found that supplemental damping reduces edge deformations and that reductions by a factor of up three are feasible with proper …

Three-Dimensional Dynamic Analysis Of Wheelchair Propulsion, Mary M. Rodgers, Srinivas Tummarakota, Junghsen Lieh

Mechanical and Materials Engineering Faculty Publications

A three-dimensional (3-D) inverse dynamic model of wheelchair propulsion was developed using the Newton-Euler method based on body coordinate systems. With this model, the arm was assumed to be three rigid segments (hand, forearm, and upper arm) connected by the wrist, elbow, and shoulder joints. A symbolic method was adopted to generate the equations of motion. The model was used to compute the joint forces and moments based on the inputs obtained from a 3-D motion analysis system, which included an instrumented wheelchair, video cameras, and a data acquisition system. The linear displacements of markers placed on the joints were …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 14, Number 2, February 1998, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Determination Of Bumper Styling And Engineering Parameters To Reduce Pedestrian Leg Injuries, Peter J. Schuster, Bradley Staines

Mechanical Engineering

The European Commission is proposing legislation aimed at reducing the severity of injuries sustained by pedestrians in the event of an impact with the front-end of a motor vehicle. One aspect of this proposed legislation is reducing the pedestrian's leg injuries due to contact with the bumper and frontal surfaces of a vehicle, assessed using a 'pedestrian leg impact device,' or 'leg-form.'

This proposed legislation presents the challenge of designing a bumper system which achieves the required performance in the leg-form impact-without sacrificing the bumper's primary function of vehicle protection during low-speed impacts. The first step in meeting this challenge …

Worst-Case Error Probability Of A Spread-Spectrum System In Energy-Limited Interference, Murad Hizlan, Brian L. Hughes

Electrical and Computer Engineering Faculty Publications

We consider a communication channel corrupted by thermal noise and by an unknown and arbitrary interference of bounded energy. For this channel, we derive a simple upper bound to the worst-case error probability suffered by a direct sequence (DS) communication system with error-correction coding, pseudorandom interleaving, and a correlation receiver. This bound is exponentially tight as the block length of the error correcting code becomes large. Numerical examples are given that illustrate the dependence of the bound on the choice of error correcting code, the type of interleaving used, and the relative energy of the Gaussian noise and arbitrary interference

Seismic Code Analysis Of Multi-Storey Asymmetric Buildings, Anthony P. Harasimowicz, Rakesh K. Goel

Civil and Environmental Engineering

Static torsional provisions in most seismic codes require that the lateral force at each floor level be applied at some distance from the reference centre at that floor. However, codes do not specify how to determine the locations of these centres. As a result, several different definitions of the reference centres are being used to implement the code analysis. This investigation examined how the results using various reference centres differ and which of these centres would lead to results that are in agreement with those of dynamic analysis. For this purpose three different buildings ranging form torsionally stiff to torsionally …

Neural Network Based Optimizing Controllers For Smart Structural Systems, Rajendra Damle, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

Neural network-based controllers for vibration suppression of smart structural systems have been reported in several recent studies. These studies have shown that in addition to conventional controller design methodologies, neural networks offer an effective basis for design and implementation of controllers. With the introduction of neural network chips like the electronically trainable analog neural network (ETANN) chip i80170NX by Intel and the Ni1000 chip by Nestor Corp., stand-alone hardware implementation of neural network-based controllers is possible. In this paper the capabilities of Intel's ETANN chip to implement linear and nonlinear controllers for smart structural systems have been investigated. A neural …

Bs News

Building Services Engineering

No abstract provided.

Water Level Sensor And Datalogger Testing And Demonstration, A. Burt, Mike Lehmkuhl, Charles M. Burt, Stuart W. Styles

BioResource and Agricultural Engineering

Electronic water level sensing equipment is becoming increasingly important for the implementation of water conservation programs in irrigation districts. A need has risen for information on costs, advantages/disadvantages, required support equipment, and required maintenance for the various options. ITRC conducted a yearlong study on water level sensors and dataloggers and produced this report.

Mechanical Properties, Structure, And Corrosion Characteristics Of Al And Al-Zn Coated Steel Sheets, Farraj El Shammari

Archived Theses and Dissertations

No abstract provided.

An Expert System For Service Industries Towards High Performance, Sherif Samir Abou Seif

Archived Theses and Dissertations

The thesis in hand deals with the problem of quality assessment in the service industry. Service quality measurement is an essential step towards high quality performance in these firms. Service industry plays an important role in the economy , it is currently realized that services are not luxurious activities but , rather an integral part of the economy since it employs the majority of employees and embraces more than half of the Gross National Product in most developed and under developed countries. The aim of this work is to construct a model for problem diagnosis and maintenance in the service …

Mechanical Behavior Of Al-Al2o3 Particulate Metal Matrix Composites Manufactured By Powder Metallurgy Techniques, Abdirahman Youssef Ahmed

Archived Theses and Dissertations

Metal matrix composite (N[MC) materials were manufactured using powder metallurgy (PM) techniques. Pure aluminum, Al, powder of mean particle size of 51 pm and alumina, AhO3, powder of 4 pm particle size were used as matrix and reinforcement, respectively. MNICs with four different weight fractions of reinforcement (e.g; Al-0wt.% AhO3, AI-2.5wt.% AhO3, Al-5wt.% AI2O3, and Al-1 0wt. %AhO3 ) were investigated The specimens were manufactured using hot compaction followed hot extrusion. Based on a preliminary study and on data published in the literature, two sets of processing parameters, designated as Scheme I and Scheme II, were used. The processing parameters …

Impact Of Flow Control Structures On River's [Sic] Self Assimilative Capacity, Dahlia Mohamed Eid

Archived Theses and Dissertations

The assessment of environmental impacts associated with existing and new water-level and flow control structures is becoming increasingly important these days. This study investigates the effect of water level control structures on the self-assimilative capacity of a river as well as other environmental impacts like the effect on fish habitat. A computer assisted model is developed to predict the change in the waste loading capacity of the river as well as its water quality, taking the dissolved oxygen as the main criteria, as a result of the change in its hydrologic and hydraulic regime. The model comprises four modules: (I) …

A Cooperative Expert System-Explanation Architecture, Samhaa R Adel El-Beltagy

Archived Theses and Dissertations

During the last few years, expert system explanation has become an active research area after recognizing chat its role goes beyond expert system verification as assumed by early systems. After examining current systems, it has been found that only a few of these meet the requirements of an end user interested in learning more about the domain being addressed by an expert system and understanding why it has reached a certain conclusion. It was also found that systems that address these requirements, do so at a very high cost) since they embed unmense amounts of knowledge in a system without …

Investigation Of Biogas Burner Optimum Operating Conditions With Respect To Nox And Combustion Efficiency, Michel Samir Sadek Farag

Archived Theses and Dissertations

The formation of pollutants emissions in any fuel combustion process is always depending on various factors, such as the fuel c01nposition, the air to fuel ratio, and combustion system aerodynamics. This work investigates the pollutants formation during the combustion of commercial n1ethane with the presence of CO2 as a diluent in varying proportions. Carbon dioxide could be found with methane in some natural gases, in biogas produced through the fermentation of organic waste, in landfills, etc. The work discusses how such presence with variable burner aerodynamics as combustion air split, and secondary combustion air swirl 1nodify significantly the thermodynamics and …

Incommensurate Magnetic Fluctuations In Yba₂Cu₃O₆.₆, Pengcheng Dai, Herbert A. Mook, Fatih Dogan

Materials Science and Engineering Faculty Research & Creative Works

We use inelastic neutron scattering to demonstrate that the low-frequency magnetic fluctuations in YBa₂Cu₃O_6.6 (T_c = 62.7 K) change from commensurate to incommensurate on cooling with the incommensurability first appearing at temperatures above T_c. For the energies studied, the susceptibility at incommensurate positions increases on cooling below T_c, accompanied by a suppression of the spin fluctuations at the commensurate points. These results suggest that incommensurate spin fluctuations may be a common feature for all cuprate superconductors.

Pulmonary Disposition Of Lipophilic Amine Compounds In The Isolated Perfused Rabbit Lung, Said H. Audi, Christopher A. Dawson, John H. Linehan, Gary S. Krenz, S. B. Ahlf, David L. Roerig

Biomedical Engineering Faculty Research and Publications

We measured the pulmonary venous concentration vs. time curves for [³H]alfentanil, [¹⁴C]lidocaine, and [³H]codeine after the bolus injection of each of these lipophilic amine compounds (LAC) and a vascular-reference indicator (fluorescein isothiocyanate-dextran) into the pulmonary artery of isolated perfused rabbit lungs. A range of flows and perfusate albumin concentrations was studied. To evaluate the information content of the data, we developed a kinetic model describing the pulmonary disposition of these LAC that was based on indicator dilution theory, and we sought a robust approach for interpreting the estimated model parameters. We found that the …

A Study Of Piezoelectric Orthorhombic Ta2O5, B. R. Jooste, Hendrik J. Viljoen

Hendrik J. Viljoen Publications

In 1985 it was first reported that monoclinic Ta₂O₅ has piezoelectric properties comparable to ZnO. In this work we report on the deposition, characterization, and qualitative assessment of the piezoelectric behavior of orthorhombic Ta₂O₅. Reactive magnetron sputtering was used to deposit thin films of Ta₂O₅ onto substrates of 316L stainless steel. Without substrate heating the crystallinity was poor. A rapid thermal anneal improved the crystallinity. The orthorhombic phase was dominantly present on all substrates. The piezoelectric property was qualitatively assessed, including a high temperature test at 650 °C.

Ccfss News February 1998, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Design Of Automotive Structural Components Using High Strength Sheet Steels Transformed Section Method For The Calculation Of Yield Moment Of Cold-Formed Steel Hybrid Beams, Chi-Ling Pan, Wei-Wen Yu

CCFSS Library (1939 - present)

INTRODUCTION It has been recognized that material properties and stress-strain relationships of sheet steel can be influenced by the strain rate. Because the member strength is also influenced by dynamic loading, a large number of research projects were conducted for a variety of structural members under specified loading conditions during past three decades. In cold-formed steel design, local buckling is one of the major design features because of the use of large width-to-thickness ratios for compression elements. For the purpose of determining the load-carrying capacity of automotive components, the effective width approach has been used. In view of the fact …

Optimum Preventive Maintenance Policies For The Amraam Missile, Scott J. Ruflin

Theses and Dissertations

The overall objective of this research effort was to formulate a preventive maintenance strategy for AMRAAM missiles subject to extended captive carry flight time. A preventive maintenance policy is only applicable if the item in question is aging, or deteriorating with time. Therefore, a supporting objective of this research is to characterize the aging process of the missile system through a non-parametric analysis of its Mean Residual Life (MRL) function. Three non-parametric, censored-data MRL function estimation techniques discussed in the literature are examined via a numerical example. All three estimation techniques provide MRL functions that exhibit greatly exaggerated decreasing trends …

Microengineered Sensor Devices With Field Emission Electron Sources, Chao Sun

Dissertations

This dissertation describes the design, simulation, fabrication, and characterization of a microengineered pressure sensor device and a microengineered mass spectrometer device, both of which use field emission cathode tip arrays as electron sources. VLSI and MEMS process techniques are used to scale down the dimensions from existing vacuum pressure sensors and mass spectrometers.

The microengineered pressure sensor device is fabricated on a silicon substrate approximately 1cm by 1cm. It consists of an electron source in the form of cathode tip array structure, an electron accelerating space which includes a gas ionization volume, and an ion collection electrode. The electrons emitted …

Performance Analysis Of The Interference Adaptation Dynamic Channel Allocation Technique In Wireless Communication Networks, Ziqiang Xu

Dissertations

Dynamic channel allocation (DCA) problem is one of the major research topics in the wireless networking area. The purpose of this technique is to relieve the contradiction between the increasing traffic load in wireless networks and the limited bandwidth resource across the air interface. The challenge of this problem comes from the following facts: a) even the basic DCA problem is shown to be NP-complete (none polynomial complete); b) the size of the state space of the problem is very large; and c) any practical DCA algorithm should run in real-time.

Many heuristic DCA schemes have been proposed in the …

Orthogonal Transmultiplexers : Extensions To Digital Subscriber Line (Dsl) Communications, Xueming Lin

Dissertations

An orthogonal transmultiplexer which unifies multirate filter bank theory and communications theory is investigated in this dissertation. Various extensions of the orthogonal transmultiplexer techniques have been made for digital subscriber line communication applications.

It is shown that the theoretical performance bounds of single carrier modulation based transceivers and multicarrier modulation based transceivers are the same under the same operational conditions. Single carrier based transceiver systems such as Quadrature Amplitude Modulation (QAM) and Carrierless Amplitude and Phase (CAP) modulation scheme, multicarrier based transceiver systems such as Orthogonal Frequency Division Multiplexing (OFDM) or Discrete Multi Tone (DMT) and Discrete Subband (Wavelet) Multicarrier …

Enhanced Terahertz Pulse Generation And Detection Using Electric Field Singularities In Photo-Conducting Antennas, Yi Cai

Dissertations

In recent years, generation of ultra-short electromagnetic pulses with frequency components in the terahertz (THz) range has been achieved by various techniques. Among those different methods, photo-conducting antennas have proven to be the most efficient source of THz radiation. THz spectrometers utilizing such photo-conducting antennas as transmitters and receivers are meanwhile routinely used for spectroscopic studies in the frequency regime between 0.1 to 5THz, which can be covered by neither conventional optical nor microwave spectrometers. However, THz emission power from the existing photo-conducting antenna is not sufficient for many applications (such as electro-optic sampling for real time THz detection and …

A Model For Travel Mode Switching, Lei Cao

Dissertations

Transportation policy research assesses the effect of policy changes such as the imposition of a parking charge or the augmentation of passenger rail service, on individual travel behavior. Over the last few decades, Conditional Lo it Model has been strongly advocated among discrete choice models for transportation policy study due to its ease of estimation and realistic outcomes.

This dissertation analyzes the necessity of the entry of constraints in the indirect utility function. These functions are used in discrete choice models and form the basis for travel demand modeling. This dissertation proposes a hypothesis that the explicit entry of constraints …

Design And Characterization Of Ultra High Frame Rate Burst Image Sensors, Rakesh K. Kabra

Dissertations

This thesis research was aimed at investigating and designing novel architectures required for ultra high frame rate (UHFR) imagers capable of operating at frame rates in excess of 10⁶ frames/sec. To demonstrate the feasibility of these architectures, a 180 x 180 element UHFR-I imager was designed and fabricated. The imager chip stored the latest 32 frames at its on-chip memory locations rather than performing a continuous readout. It was demonstrated that this architecture approach could achieve a frame acquisition rate of 2 x 10⁶ frames/sec. Additionally, other novel design features were incorporated to minimize optical cross talk and …

Dual Material Gate Field Effect Transistor (Dmg-Fet), Wei Long

Dissertations

Improving performance and suppressing short channel effects are two of the most important issues in present field effect transistors development. Hence, high performance and long channel like behaviors are essential requirements for short channel FETs. This dissertation focuses on new ways to achieve these significant goals. A new field effect transistor - dual material gate FET (DMG-FET) - is presented for the first time. The unique feature of the DMG-FET is its gate which consists of two laterally contacting gate materials with different work functions. This novel gate structure takes advantage of material work function difference in such a way …

Decentralized Reliable Control For Large-Scale Lti Systems, Zhengfang Chen

Dissertations

Reliable control concerns the ability of closed loop system to maintain stability and regulation properties during arbitrary sensor, controller, and actuator failure. Reliable control research has been an active research topic for more than 10 years.

Recent approach for reliable control includes the H∞ method, the algebraic factorization design, and the robust servomechanism control. These methods have been surveyed and discussed in this thesis with the robust servomechanism control methodology serving as the basis of the research development of this work.

In this thesis, the reliable control for large-scale, multi-input/output linear system is considered. Two concepts of reliable control …

Cantilever Beam Microactuators With Electrothermal And Electrostatic Drive, Murat M. Okyar

Dissertations

Microfabrication provides a powerful tool for batch processing and miniaturization of mechanical systems into dimensional domain not accessible easily by conventional machining. CMOS IC process compatible design is definitely a big plus because of tremendous know-how in IC technologies, commercially available standard IC processes for a reasonable price, and future integration of microma-chined mechanical systems and integrated circuits. Magnetically, electrostatically and thermally driven microactuators have been reported previously. These actuators have applications in many fields from optics to robotics and biomedical engineering.

At NJIT cleanroom, mono or multimorph microactuators have been fabricated using CMOS compatible process. In design and fabrication …