Engineering Commons^™

Ccfss News February 1993, Wei-Wen Yu Center For Cold-Formed Steel Structures

CCFSS Newsletters (1999 - 2008)

No abstract provided.

Why American Engineers Aren't Unionized - A Comparative Perspective, Peter F. Meiksins, Chris Smith

Sociology & Criminology Faculty Publications

This article presents a comparative perspective on why U.S. engineers are not unionized. The decline of organized labor in the U.S. has stimulated a new interest in comparative research. Explanations of the prolonged stagnation and contraction of the U.S. labor movement that focus on the U.S. alone run the risk of assuming that the U.S. case is normal, and that the decline of organized labor is a structural inevitability of advanced capitalism. By broadening their scope to include other industrialized countries with similar political economies and different labor histories, students of the labor movement will be better able to identify …

Tissue Characterization And Imaging Using Photon Density Waves, Lars O. Svaasand, Bruce J. Tromberg, Richard C. Haskell, Tsong-Tseh Tsay, Michael W. Berns

All HMC Faculty Publications and Research

The optical properties of brain tissues have been evaluated by measuring the phase velocity and attenuation of harmonically modulated light. The phase velocity for photon density waves at 650-nm wavelength has been found to be in the range of 5 to 12% of the corresponding velocity in a nonscattering medium, and the optical penetration depth was in the range 2.9 to 5.2 mm. These results are used to predict the resolution of optical imaging of deep tissue structures by diffusely propagating incoherent photons. The results indicate that structures of a few millimeters in linear dimension can be identified at 10 …

Open-Ended Rectangular Waveguide For Nondestructive Thickness Measurement And Variation Detection Of Lossy Dielectric Slabs Backed By A Conducting Plate, Sasan Bakhtiari, Stoyan I. Ganchev, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Solutions of fields inside a slab of a generally lossy dielectric medium backed by a conducting plate, placed outside a waveguide-fed rectangular aperture, are evoked in the application to the microwave nondestructive thickness measurement of such dielectric slabs. Upon construction of the waveguide terminating admittance expression from its variational form, an inverse problem is then solved to extract the slab thickness from the conductance and susceptance in a recursive manner. A comparison between the experimental and theoretical results showed that the significance of higher order modes is minimal; hence, the dominant mode assumption is, in general, valid to describe the …

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 9, Number 2, February 1993, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

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

Enhancements To Procedure For Estimating Esals, John A. Deacon, Jerry G. Pigman, Neil Tollner, David Cain

Kentucky Transportation Center Research Report

Kentucky's current procedure for estimating equivalent single axle loads (ESALs) was updated in 1990 to incorporate traffic data categorized by functional class rather than by statewide averages. This change resulted from the influx of data generated by automatic equipment used to classify and weigh vehicles in motion. A much wider range of geographic conditions and road conditions was sampled, and the expectation was that the data used in the estimation procedure would be more accurate as a result.

The 1990 revisions were quite extensive, and, although model calibrations using 1989 and 1990 data have proven useful, the Division of Planning …

Installation And Performance Of Portland Cement Concrete Pavement Joint Sealers, David Q. Hunsucker, Edgar E. Courtney, Michael D. Stone

Kentucky Transportation Center Research Report

Joints are needed in portland cement concrete pavements to control cracking, relieve pavement stresses due to volume change, and to protect immovable structures. However, when the joints are not properly designed, constructed, and maintained, they may become a source of multiple problems. It is the opinion of many pavement management engineers that the most effective way to prevent and/or correct problems with joints is to use a joint sealer material. The purpose of the sealer is to keep surface water and fine, incompressible material from entering the pavement joint.

The Kentucky Transportation Center was contracted by the Kentucky Department of …

Using Spreadsheets To Teach Problem Solving In A First Year Class, A. John Boye, P. F. Williams, Rodney J. Soukup

P. F. (Paul Frazer) Williams Publications

The “problem solving” portion of a two semester first year electrical engineering course is described. This course makes use of personal computers and spreadsheets to try to improve students’ problem solving skills. The goal is to give students a better understanding of engineering concepts and not just mathematical details. In addition to describing the course contents, a brief review of the rationale that was used in selecting the hardware and software used in the course is also given.

Optimal Control And Estimation For Discrete-Time Periodic And Multirate Systems, Vikram Kapila

Theses and Dissertations

For linear time-invariant systems it has been shown that the solutions to the optimal reduced-order modeling, estimation, and control problems can be characterized using optimal projection equations, sets of Riccati and Lyapunov equations coupled by terms containing a projection matrix. These equations provide a strong theoretical connection between standard full-order results such as linear-quadratic Gaussian theory and have also proved useful in the comparison of suboptimal reduction methods with optimal reduced-order methods. In addition, the optimal projection equations have been used as the basis for novel homotopy algorithms for reduced-order design. This thesis considers linear periodic plants and develops necessary …

Bs News

Building Services Engineering

No abstract provided.

Critical Shear Stress And Critical Flow Rates For Initiation Of Rilling, John E. Gilley, W. J. Elliot, J. M. Laflen, J. R. Simanton

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study was conducted to identify critical shear stress and critical flow rates required to initiate rilling on selected sites. The data used in this investigation were collected from soils located throughout the USA where crop residues had been removed, and moldboard plowing and disking had occurred. Runoff and soil loss measurements were made on sites where simulated rainfall was applied to preformed rills. Multiple regression analyses were used to relate critical shear stress values and critical flow rates to selected soil properties. The soil-based regression equations were found to provide reliable estimates. Information identified in this study will improve …

Explicit Asymmetric Bounds For Robust Stability Of Continuous And Discrete-Time-Systems, Zhiqiang Gao, P J. Antsaklis

Electrical and Computer Engineering Faculty Publications

The problem of robust stability in linear systems with parametric uncertainties is considered. Explicit stability bounds on uncertain parameters are derived and expressed in terms of linear inequalities for continuous systems and inequalities with quadratic terms for discrete-time systems. Cases where system parameters are nonlinear functions of an uncertainty are also examined

Analysis Of The Optimum Extraction System Design For The Separation And Purification Of Rare Earths, Kenneth Yeon-Kang Chan

Dissertations

A mathematical model for the liquid-liquid equilibrium of the lanthanide and yttrium oxides in the nitric acid - water - tributyl phosphate (HNO₃-H₂O-TBP) two-phase system has been developed. This model is based on the interrelationships of chemical reactions, phase equilibrium, and material balance. The chemical reactions were modelled using experimentally derived empirical equations for components involved. The distribution coefficients of 16 rare earths which were experimentally determined. by UK Harwell Laboratory were used to evaluate the parameters of this equilibrium model. Once model parameters are determined, material balance for all species in the HNO₃-H …

Analysis Of A Band-Saw, Suat Ali Ozsoylu

Dissertations

The solution for the transverse oscillations of a band-saw is determined. Two different models are treated: a fourth-order model and a second-order model. The response characteristics for both models are determined using Laplace transformation. To obtain the inverse Laplace Transform for the fourth-order model, it was necessary to fmd the frequencies by applying the Extended Lanczos Method in order to overcome the problem for computer overflow.

The limits of stability for both models are studied by plotting the eigenvalues against changing parameter values. Conditions for the onset of divergence and flutter instabilities, which need to be taken into account in …

Kinematic Synthesis Of Adjustable Four-Bar Mechanisms For Multi-Phase Motion Generation, Shao Jie Wang

Dissertations

A four-bar linkage can satisfy up to five prescribed positions for the motion generation problem. The adjustable four-bar linkage, on the other hand, can satisfy more than five given positions by making some of the parameters adjustable.

Limited work had been done in the area of motion generation problems of kinematic synthesis of adjustable four-bar linkages until Wilhelm introduced the concept of multiple adjustments.

This study considers for the first time, the adjustment of a moving pivot, and the problems of three phases of motion. Various combinations of the number of prescribed positions for the motion generation problems are solved …

Study Of Surface Properties Produced By Magneto-Plasma On Nitriding For Improving Wear Resistance, I-Tsung Shih

Dissertations

In this work a newly developed surface treatment process, Magneto-Plasma Ion Nitriding process, was developed and studied. This process was developed to increase durability and wear resistance of operational surfaces of different machine components.

In this study, orthogonal experimental analysis was used to develop, optimize, and select the process parameters. Coating layers were characterized and studied by using scanning electron microscopy(SEM), Auger electron spectroscopy(AES), and image analysis system. The influence of different process treatment parameters, such as temperature, nitrogen concentration, and magnetization, on the layers properties was studied. The mechanism of layer formation and bonding was proposed and a mathematical …

Investigation Of The Striation Formation In The Course Of Abrasive Waterjet Cutting, Jo-Fei Chao

Dissertations

The principal defect of the surfaces generated by abrasive waterjet machining is excessive waviness (striation). The existing theories of striation formation are not adequate to explain this phenomenon. The presented study is concerned with the development of an understanding of the mechanism of striation formation.

A spectral analysis of temporal process and spatial surface characteristics demonstrated that the striation is caused by nozzle vibration that is due to the conditions of the motion control of the nozzle. This enabled us to discover a means for improving the surface finish. From a study of the surface spectra, it was found that …

Investigation Of The Consumer Electronics Bus, Jaesoo Yang

Dissertations

The objectives of this dissertation are to investigate the performance of the Consumer Electronics Bus (CEBus) and to develop a theoretical formulation of the Carrier Sense Multiple Access with Contention Detection and Contention Resolution (CSMA/CDCR) with three priority classes protocol utilized by the CEBus

A new priority channel assigned multiple access with embedded priority resolution (PAMA/PR) theoretical model is formulated. It incorporates the main features of the CEBus with three priority classes. The analytical results for throughput and delay obtained by this formulation were compared to simulation experiments. A close agreement has been found thus validated both theory and simulation …

On Adaptive Censored Cfar Detection, Loizos Anastasiou Prastitis

Dissertations

In an automatic radar detection system the received signal in every range resolution cell is compared with a threshold to test for the presence of a target. A Neyman-Pearson type test is used which maximizes the probability of detection for a fixed probability of false alarm. For the simple case where the noise is homogeneous a fixed threshold is chosen to achieve the designed constant false alarm rate (CFAR). In the more realistic case the noise background is non-stationary due to clutter and interference. In this situation, the threshold used for testing a particular cell is usually set adaptively using …

Investigation Of Reactor Design Parameters Towards Optimizing Biodegradation Of Chlorophenols By Phanerochaete Chrysosporium, Nirupam Pal

Dissertations

The biodegradation of 2,4,6-trichlorophenol (246-TCP) and 2,4,5-trichiorophenol (245-TCP) by Phanerochaete chrysosporium was studied in batch and in continuous systems. Contrary to most of the previous reports from the literature, this study shows that degradation of both TCPs can occur in the absence of any measurable ligninase activity. The microorganism did not retain its degradative ability for more than about two weeks

In order to better understand the degradation process, the individual contributions of both the biomass and the extracellular proteins were studied separately. The results show that neither the biomass nor the extracellular proteins alone can completely degrade 246-TCP, but …

A Sign-To-Speech Translation System, Koka Veera Raghava Rao

School of Computing: Dissertations, Theses, and Student Research

This thesis describes sign-to-speech translation using neural networks. Sign language translation is an interesting but difficult problem for which neural network techniques seem promising because of their ability to adjust to the user's hand movements, which is not possible to do by most other techniques. However, even using neural networks and artificial sign languages, the translation is hard, and the best-known system, that of Fels & Hinton (1993), is capable of translating only 66 root words and 203 words including their conjugations. This research improves their results to 790 root signs and 2718 words including their conjugations while preserving a …

Computer Aided Manufacturing For Production Environment, Biren K. Parikh

Theses

Investments in new technology like Computer Aided Manufacturing (CAM) increased in the past few years because of the foreign competition in the world market as well as on the home ground. Improper investment in CAM and CIM resulted in the "Islands of Automation" instead of an integrated system. These "Islands of Automation" have created new problems for production planning and factory communication.

The objective of the thesis is to develop the methodology to selection and implementation of the CAM system in the production environment. It is to be noted that a CAM system is part of the overall CIM implementation, …

Translation Of Images On The Hypercube Using Leaf Codes, Bhavesh Patel

Theses

Image processing is used for manipulation of pictorial images. Image analysis applications are typically characterized by the need to process large quantities of image data. Some of the important transformations or operations which are car¬ried out by image processing systems are translation, scaling, superposition and rotation. Algorithms have been developed to carry out these transformations on image regions represented by quadtrees. Gargantini introduced an algorithm to translate an image region represented by a linear quadtree or leafcodes. A linear quadtree is a space efficient data structure used for storing digital images. Ziavras et.al. have proposed a modification of Gargantini's algorithm …

Optical Flow Determination And Motion Analysis, Qian Wang

Theses

Optical flow, also known as image flow, is of fundamental importance in the processing of image sequences. Various approaches to determine optical flow have been proposed --- others continue to appear. Using several sets of real image sequences, here, the results of three different approaches to the the determination of optical flow are reported, the approaches are the Gradient-based approach, the Correlation-based approach and the Correlation-feedback approach. The comparisons are primarily empirical, and they show that the performance of these different algorithms differs significantly among the different image sequences, indicating that there does not exists one superior algorithm which could …

Simulation Study For The Effect Of Dependencies In Queueing Systems, Yitao Bai

Theses

Few theoretical results have been obtained in the literature for the effects of dependencies between random variables on the performance of queueing systems. This thesis aims at investigating this issue via simulation. Several dependencies are studied in detail, including dependencies between interarrival times, between interarrival time and service time, between service times and dependencies between different stages in networks of queues. We define several classes of dependent random variables and study their correlation coefficients, then we apply them to single and multiple station service systems. Comparisons with the independent case, for which the explicit form solution are available, are made …

Timed Petri Net Simulation Of Flexible Manufacturing Systems, Yan Chen

Theses

Standard Petri nets have been used to model and analyze Flexible Manufacturing Systems. The timed Petri net, which can incorporate the time delay associated with manufacturing events, provides additional information about real time behavior of practical systems. The Timed Petri Net Simulation Tool, a highly interactive graphical tool, is applied to simulate the modeled flexible manufacturing systems. Timed Petri net models are experimented with. Machine utilization data and throughput are obtained. Analysis of the results shows that the system performance can be optimized by choosing proper parameters.

Evaluation Of Truck Restrictions Using Simulation, Shaikh Mohamed Arif

Theses

Traffic congestion is a major problem in many central business districts. Many strategies have been proposed and implemented to solve or alleviate this problem. One of the most common strategies is to impose travel restrictions on the movement of trucks, without reviewing the economic consequences of goods movement restrictions on shippers, customers and on the overall business activity of the area.

This research examines the effect of various truck restrictive policies on the cost of urban goods movement, using the central business district of Manhattan as a case study. Computer simulation techniques are used to evaluate several scenarios under different …

Pressure Swing Absorption-Based Separation Of A Gas Mixture, Syamalendu Bhaumik

Theses

In this study, separation of a gas mixture was investigated using the novel concept of pressure swing absorption in a stationary absorbent liquid. The best features of pressure swing adsorption, gas liquid scrubbing and hollow fiber based membrane processes were incorporated to develop the process.

A well-packed microporous hydrophobic hollow fiber module was used to achieve absorption of a gas at a high pressure into a liquid during a certain part of the cycle followed by desorption of the gas from the liquid in the other part of the cycle. The device has a very high interfacial area per unit …

Behavior Of R/C Columns Under Nonproportional Variations In Axial And Lateral Loads, Kaniz Fatema Ahsan

Theses

The study on the behavior of reinforced concrete columns subjected to the motion of earthquake suggests that the structure may experience nonproportional variations in axial and lateral forces. In order to assess the capacity of a reinforced concrete structure under nonproportional loadings, an analytical model is developed using the fiber modeling technique.

The method is based on detailed analytical description of the geometry and material properties used in evaluating the behavior of the critical regions rather than a simplified and predefined set of hysteresis rules. The present study has two principal components of investigation. First, the analyses are done at …

A Successive Approximation Algorithm To Solve Motion Planning Problems, Cheng-Ming Chang

Theses

A successive approximation algorithm is presented to solve motion planning problems and optimal control problems. A motion planning problem is included in an optimal control problem and due to the heavily nonlinear and coulped differential equations describing the dynamics of the manipulator and several constraints imposed on the system, few efficient methods exist to solve this kind of problems.

The successive approximation algorithm can decompose the global nonlinear problem into several nonlinear subproblems and each subproblem is solved by the nonlinear programming method with a highly convergent rate. Because the limited constraints and variables are included in each subproblem and …