Engineering Commons^™

Evaluation Of Nsp To Estimate Seismic Deformation: Sdf Systems, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

Investigated in this paper is the approximation in the ATC-40 nonlinear static procedure (NSP) that the earthquake-induced deformation of an inelastic single-degree-of-freedom (SDF) system can be estimated by an iterative method requiring analysis of a sequence of equivalent linear systems. Several deficiencies in the ATC-40 Procedure A are demonstrated. This iterative procedure did not converge for some of the systems analyzed. It converged in many cases, but to a deformation much different than dynamic (nonlinear response history or inelastic design spectrum) analysis of the inelastic system. The ATC-40 Procedure B always gives a unique value of deformation, same as that …

Seismic Behaviour Of Asymmetric Buildings With Supplemental Damping, Rakesh K. Goel

Civil and Environmental Engineering

This paper investigates the response of asymmetric‐plan buildings with supplemental viscous damping to harmonic ground motion using modal analysis techniques. It is shown that most modal parameters, except dynamic amplification factors (DAFs), are affected very little by the plan‐wise distribution of supplemental damping in the practical range of system parameters. Plan‐wise distribution of supplemental damping significantly influences the DAFs, which, in turn, influence the modal deformations. These trends are directly related to the apparent modal damping ratios; the first modal damping ratio increases while the second decreases as CSD moves from right to left of the system plan, and their …

A Special Theory Of Biphasic Mixtures And Experimental Results For Human Annulus Fibrosus Tested In Confined Compression, Stephen M. Klisch, Jeffrey C. Lotz

Mechanical Engineering

A finite deformation mixture theory is used to quantify the mechanical properties of the annulus fibrosus using experimental data obtained from a confined compression protocol. Certain constitutive assumptions are introduced to derive a special mixture of an elastic solid and an inviscid fluid, and the constraint of intrinsic incompressibility is introduced in a manner that is consistent with results obtained for the special theory. Thirty-two annulus fibrosus specimens oriented in axial (n = 16) and radial (n = 16) directions were obtained from the middle-lateral portion of intact intervertebral discs from human lumbar spines and tested in a stress-relaxation protocol. …

Profiling The Performance Of Tcp/Ip On Windows Nt, P. Xie, M. Liu, J. Harris, C. Scheiman

Electrical Engineering

This paper presents detailed network performance measurements of a prototype implementation of the TCP/IP network software on Windows NT. The measurements include latency, throughput, and CPU utilization of the protocol stack and for some key operations within the stack

A Conformal Finite Difference Time Domain (Cfdtd) Algorithm For Modeling Perfectly Conducting Objects, Wenhua Yu, Raj Mittra, Dean Arakaki, Douglas H. Werner

Electrical Engineering

In this paper, the authors present a new and robust conformal Finite Difference Time Domain (FDTD) algorithm for the accurate modeling of perfectly conducting objects with curved surfaces and edges. We illustrate the application of this approach by analyzing a number of representative antenna and cavity problems. These include a quarter wave monopole mounted on a perfectly conducting elliptic disk, a circular patch antenna, and a cylindrical cavity. We validate the me~od by comparing the results for the pattern, impedance and resonant frequency, etc., with those derived by using other techniques.

A Technique For Analyzing Radiation From Conformal Antennas Mounted On Arbitrarily-Shaped Conducting Bodies, Dean Arakaki, Douglas H. Werner, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve the problem of radiation from conformal aperture and microstrip antennas mounted on arbitrarily-shaped conducting bodies. The method, based on the surface equivalence and reciprocity principles, uses a combination of the Finite Difference Time Domain (FDTD) and Method of Moments (MoM) techniques to substantially improve the computational efficiency of the radiation pattern calculation. When the geometry and location of the radiating element are modified, only a small portion of the overall analysis requires re-simulation. This leads to a significant improvement in computational efficiency over presently-used techniques, and can substantially improve design efficiency when …

Supersonic Channel Airfoils For Reduced Drag, Stephen M. Ruffin, Anurag Gupta, David D. Marshall

Aerospace Engineering

A proof-of-concept study is performed for a supersonic channel-airfoil concept,which can be applied to the leading edges of wings, tails, fins, struts, and other appendages of aircraft, atmospheric entry vehicles, and missiles in supersonic flight. It is designed to be beneficial at conditions in which the leading edge is significantly blunted and the Mach number normal to the leading edge is supersonic.The supersonic channel-airfoil concept is found to result in significantly reduced wave drag and total drag (including skin-friction drag) and significantly increased lift/drag although maximum heat-transfer rate was increased for the geometries tested.

Evaluation Of Infrared And Millimeter-Wave Imaging Technologies Applied To Traffic Management, C. Arthur Maccarley, Brian M. Hemme, Lawrence Klein

Electrical Engineering

This paper reviews the findings of a study commissioned by the California Department of Transportation to evaluate the potential of infrared and passive millimeter-wave imaging technologies for traffic surveillance and automated detection. Images formed from radiation at infrared and millimeter wavelengths are characterized by fundamentally different information compared with visible-spectrum images, and generally improved ability to penetrate obscured atmospheres such as fog or dust.

Ten examples of commercially available infrared (IR) imaging technologies and one experimental passive millimeter-wave (MMW) radiometric imaging apparatus were evaluated with respect to the specific requirements of highway monitoring and traffic management. A suite of traffic …

Photoresist Coating Process Control With Solvent Vapor Sensor, Richard N. Savage, Herbert Litvak, Emir Gurer

Materials Engineering

An apparatus for spin coating surfaces with liquid polymer comprises a spin coating chamber having a rotatable chuck for supporting an object to be coated. A distributor introduces gases into the chamber. A solvent vapor and carrier gas supply provides a carrier gas having a controlled level of solvent vapor therein within the range of from 0 to saturation concentrations of solvent vapor. A solvent vapor sensor is positioned with respect to the coating chamber to produce signals which correspond to the concentration of solvent vapor in the coating chamber. A control means is connected to the solvent vapor concentration …

Adsorption Of Pb And Cd Onto Metal Oxides And Organic Material In Natural Surface Coatings As Determined By Selective Extractions: New Evidence For The Importance Of Mn And Fe Oxides, Deming Dong, Yarrow M. Nelson, Leonard W. Lion, Michael L. Shuler, Whilliam C. Ghiorse

Civil and Environmental Engineering

Surface coatings (biofilms and associated minerals) were collected on glass slides in the toxic surface waters of Cayuga Lake (New York State, U.S.A.) and were used to evaluate the relative contributions of Fe, Mn and Al oxides and organic material to total observed Pb and Cd adsorption by the surface coating materials. Several alternative selective extraction techniques were evaluated with respect to both selectivity and alteration of the residual unextracted material. Pb and Cd adsorption was measured under controlled laboratory conditions (mineral salts solution with defined metal speciation, ionic strength 0.05 M, 25°C and pH 6.0) before and after extractions …

Electroluminescent Display Device Including Active Polymer Layer, Aemilianus G. J. Staring, David Braun, Karel E. Kuijk

Electrical Engineering

Control device for an electroluminescent display device, comprising an active layer of a semiconducting polymer of, for example pixels arranged in the form of a matrix, reducing flicker and crosstalk. The control device may be based on voltage control at which voltages across the pixels are at least 1.6 V, but is preferably based on current control, at which the duration of the data pulses determines the grey level.

Benchmarking Of Flexibility And Needs - 2000, Charles Burt, Andrew Mutziger, Darren Cordova

BioResource and Agricultural Engineering

ITRC interviewed irrigation district personnel from 60 agricultural districts representing approximately 91% of the irrigated acreage within the U.S. Department of the Interior Bureau of Reclamation’s (USBR) Mid-Pacific Region.

Data were analyzed to determine the degree of water delivery flexibility provided to farmers and the extent of existing and planned district modernization.

The interview process defined needs for direct technical assistance and training. These needs varied by district and area in California. The Irrigation Training and Research Center (ITRC) concluded that training programs should incorporate some common classes using the Water Delivery Facility and other resources located on campus at …

Evaluation Of Anti-Fouling Paints, Charles M. Burt

BioResource and Agricultural Engineering

Algae and other growth on Replogle flumes, often used as flow measurement devices in irrigation canals, can effect the accuracy of measurements in those canals. Research was conducted to find a product that would prevent buildup on the flumes. Hard anti-fouling paint, designed to be applied to concrete rather than fiberglass, wood, steel or iron, was the type of paint used in this study.

Ultrasonic Testing For Compacted Clayey Soils, Nazli Yesiller, Gokhan Inci, Carol J. Miller

Civil and Environmental Engineering

In this study, tests were conducted to investigate the use of ultrasonic methods to determine compaction characteristics of clayey soils. In particular, through-transmission test method was used to determine P-wave velocities in compacted clayey soils. Effects of soil type and compaction conditions on velocity were investigated. Tests were conducted on three soils that had low, medium, and high plasticity. Soils were prepared at water contents ranging from dry to wet of optimum using standard and modified compaction efforts. It was observed that velocity increased with increasing compactive effort and decreasing plasticity and clay content. Moreover, the variation of ultrasonic velocity …

Thermal Properties Of High Water Content Materials, James L. Hanson, Tuncer B. Edil, Nazli Yesiller

Civil and Environmental Engineering

Fundamental thermal properties of various high water content materials were determined using a number of thermal testing methods. Tests were conducted on peat soils, solid wastes, industrial sludge, and bentonite slurries. Thermal conductivity, heat capacity, and thermal diffusivity were determined. The thermal conductivity of the materials was determined using a needle probe method. The volumetric heat capacity of the materials was determined using a dual probe method. These values were used together to obtain thermal diffusivity. Analytical methods are also used to determine heat capacity and thermal diffusivity. The theory for determination of thermal parameters using the various methods is …

Unsaturated Performance Comparison Of Compacted Clay Landfill Liners, Carol J. Miller, Saad Merayyan, Nazli Yesiller

Civil and Environmental Engineering

Tests were conducted to determine the variation in volumetric water content and pore water suction for a variety of compacted clay soils used in the construction of landfill liners. The fit of the experimental data to an existing parametric model was investigated for two different fitting techniques. The first technique involves the use of the retention curve computer program (RETC) developed for the U.S. EPA. The second technique employs the Solver subroutine included in Microsoft Excel. The parametric models resulting from either technique correlated well to the experimental data. However, the individual curve fit parameters varied significantly. The effect of …

Random Vibration Studies Of An Sdof System With Shape Memory Restoring Force, L. Duval, Mohammad N. Noori, Z. Hou, H. Davoodi, S. Seelecke

Office of the Dean (CENG) Scholarship

Intelligent and adaptive material systems and structures have become very important in engineering applications. The basic characteristic of these systems is the ability to adapt to the environmental conditions. A new class of materials with promising applications in structural and mechanical systems is shape memory alloy (SMA). The mechanical behavior of shape memory alloys in particular shows a strong dependence on temperature. This property provides opportunities for the utilization of SMAs in actuators or energy dissipation devices. However, the behavior of systems containing shape memory components under random excitation has not yet been addressed in the literature. Such a study …

A Review Of Battery Exchange Technology For Refueling Of Electric Vehicles, C. Arthur Maccarley

Electrical Engineering

The limited energy storage and long recharge time and of electric vehicle batteries have motivated several alternatives to in-vehicle slow charging. Solutions generally fall into three categories: (1) fast charging, in which batteries are charged in-vehicle at an accelerated rate, (2) battery material reloading or refueling, in which the energy-carrying elements of the battery are physically replaced or replenished, and (3) battery interchange, involving the complete exchange of the battery pack, usually with the aid of some semi-automated mechanism. Among these options, the last, battery interchange, has tended to receive the least industry attention, but has been an expansive topic …

Actuators For Sluice Gates — Alternatives To Commercially Available Products, Charles M. Burt

BioResource and Agricultural Engineering

Gate actuators provide a method of raising and lowering canal gates using electric motors instead of human power. ITRC has investigated four alternatives to commercially available actuators designed specifically for the operation of canal gates.

Technology In Engineering Education: What Do The Faculty Know (And Want) Anyway?, John C. Chen, Michael Ellis, Jason Lockhart, Sameer Hamoush, Catherine E. Brawner

Mechanical Engineering

We have conducted a survey of engineering faculty at the eight SUCCEED coalition universities to identify the training needs and present levels of experience with various technologies. The results of that survey are presented in this paper.

The most surprising finding from the survey is that, despite the wide differences in the Coalition’s colleges of engineering (in size, student demographics, and research-teaching emphasis, for example), the survey results are similar for all campuses. This is important in that it implies that the survey results may be widely applicable to other universities, even given the disparate state of technology integration and …

An Efficient Cnc Programming Approach Based On Group Technology, Manocher Djassemi

Industrial Technology and Packaging

Many studies and reports support the significant impact of the application of group technology on various aspects of product design and manufacturing. The fact that group technology is the common solution to similar problems is the main source of such impact. In this paper, one of the less frequently utilized features of CNC technology known as parametric part programming is used to implement the common solution feature of group technology in processing a set of similar parts. Using three part families, the advantages of blending the concept of group technology and parametric programming for CNC machining operations are illustrated. The …

Behavior Of Gamma Tial Subjected To Impact Damage And Elevated Temperature Fatigue, Trevor S. Harding, J. Wayne Jones

Materials Engineering

Gamma titanium aluminide has received significant attention in recent years as a candidate material for use in aerospace and industrial gas turbine engine applications. In particular, these materials offer significant weight reductions (densities are less than half that of nickel-based superalloys), high specific strength retention at elevated temperature and high specific stiffness which is particularly important in vibrating components such as blades. This combination of weight savings and good mechanical properties has led to the possibility that γ-TiAl may be a suitable replacement for nickel-based alloys, such as Inconel 718, in low pressure turbine blades without significant redesign of the …

Internally Constrained Mixtures Of Elastic Continua, Stephen M. Klisch

Mechanical Engineering

A treatment of internally constrained mixtures of elastic continua at a common temperature is developed. Internal constraints involving the deformation gradient tensors and the common mixture temperature are represented by a constraint manifold, and an internally constrained mixture of elastic continua is associated with each unique equivalence class of unconstrained mixtures. The example of intrinsic incompressibility of each constituent first proposed by Mills is discussed.

Electroluminescent Device Comprising A Transparent Structured Electrode Layer Made From A Conductive Polymer, Aemilianus G. J. Staring, David Braun

Electrical Engineering

A description is given of an electroluminescent (EL) device (1) composed of polymeric LEDs comprising an active layer (7) of a conjugated polymer and a transparent polymeric electrode layer (5) having electroconductive areas (51) as electrodes. Like the active layer (7), the electrode layer (5) can be manufactured in a simple manner by spin coating. The electrode layer (5) is structured into conductive electrodes (51) by exposure to UV light. The electrodes (9) and (51) jointly form a matrix of LEDs for a display. When a flexible substrate (3) is used, a very bendable EL device is obtained.

Collaborative Undergraduate Research, Hamid Davoodi, Frederick Just, Ali Saffar, Mohammad Noori, William W. Durgin

Office of the Provost Scholarship

A joint undergraduate research project between University of Puerto Rico at Mayagüez (UPRM) and Worcester Polytechnic Institute (WPI) started four years ago. Each year a group of students, varying between six and ten, from WPI will come to Puerto Rico to work with a group of students, varying from six to ten, from UPRM on a well defined research project. Although the topics of the projects have been different but all follow the same goal, Vibration Control of Structures by Utilizing Shape Memory Alloys. Each year the project starts on January and ends on May. Both groups of the students …

Simtrainer: A Management Training Tool, Wade Stark, Sema E. Alptekin

Industrial and Manufacturing Engineering

Abstract published of poster paper presented at conference.

Scheduling Semiconductor Device Test Operations On Multihead Testers, Tali Freed, Robert C. Leachman

Industrial and Manufacturing Engineering

Past attempts to devise scheduling methods for the device test operations of semiconductor manufacturing firms fail to address a significant characteristic of multiple-head test systems—the dependency of processing rates on the lots processed simultaneously on the testers. Since the problem has never been modeled accurately in the scheduling literature, feasibility and performance of previously proposed scheduling methodologies for multihead testers may not be accurately assessed. In this paper, we describe the multihead tester scheduling problem, present an enumeration solution procedure, and illustrate the problems of previously suggested tester scheduling algorithms.

Capacity‐Demand‐Diagram Methods Based On Inelastic Design Spectrum, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

An improved capacity‐demand‐diagram method that uses the well‐known constant‐ductility design spectrum for the demand diagram is developed and illustrated by examples. This method estimates the deformation of inelastic SDF systems consistent with the selected inelastic design spectrum, while retaining the attraction of graphical implementation of the ATC‐40 Nonlinear Static Procedure. One version of the improved method is graphically similar to ATC‐40 Procedure A whereas the second version is graphically similar to ATC‐40 Procedure B. However, the improved procedures differ from ATC‐40 procedures in one important sense. The demand diagram used is different: the constant‐ductility demand diagram for inelastic systems …

An Evaluation Of Ploughing Models For Orthogonal Machining, Daniel J. Waldorf, Richard E. Devor, Shiv G. Kapoor

Industrial and Manufacturing Engineering

An analytical comparison is made between two basic models of the flow of workpiece material around the edge of an orthogonal cutting tool during steady-state metal removal. Each has been the basis for assumptions in previous studies which attempt to model the machining process, but no direct comparison had been made to determine which, if either, is an appropriate model. One model assumes that a separation point exists on the rounded cutting edge while the other includes a stable build-up adhered to the edge and assumes a separation point at the outer extreme of the build-up. Theories of elastic-plastic deformation …

Lead Binding To Metal Oxide And Organic Phases Of Natural Aquatic Biofilms, Yarrow M. Nelson, Leonard W. Lion, Michael L. Shuler, William C. Ghiorse

Civil and Environmental Engineering

The role of the composition of surface-coating materials in controlling trace metal adsorption in aquatic environments was investigated using natural biofilms that developed on glass slides in three New York State lakes and a water-supply well. Adsorption isotherms were obtained for Pb binding to each of the biofilms in solutions with defined Pb speciation at 25°C and pH 6.0, with Pb concentrations ranging from 0.2 to 2.0 μM. Adsorption isotherms for Pb binding to laboratory-derived metal oxides and surrogate organic materials were determined under the same conditions. These isotherms, combined with characterization of natural biofilm composition, were used to estimate …