Engineering Commons^™

Development Of Strength Theories For Random Fiber Composites, Victor Giurgiutiu

Faculty Publications

A ressessment of existing theories for calculating the strength of random and quasi-random fiber composites is presented. Fundamental aspects regarding the physical model, macromechanics analysis, fiber distribution functions, generalized failure criterion, and progressive versus sudden failure models are covered first. Progressive ductile failure, progressive brittle failure, and sudden brittle failure are treated in detail. In each case, the original theory is briefly reviewed, and then its extensions accompanied by numerical examples are presented. Several limitations originally imposed by Hahn, such as the monotonically nonincreasing requirement on the failure strain curve, are lifted and the mathematical formulations are generalized. Some common …

The World Wide Web And Technology Transfer At Nasa Langley Research Center, Michael L. Nelson, David J. Bianco

Computer Science Faculty Publications

NASA Langley Research Center (LaRC) began using the World Wide Web (WWW) in the summer of 1993, becoming the first NASA installation to provide a Center-wide home page. This coincided with a reorganization of LaRC to provide a more concentrated focus on technology transfer to both aerospace and non-aerospace industry. Use of the WWW and NCSA Mosaic not only provides automated information dissemination, but also allows for the implementation, evolution and integration of many technology transfer applications. This paper describes several of these innovative applications, including the on-line presentation of the entire Technology Opportunities Showcase (TOPS), an industrial partnering showcase …

Electronic Document Distribution: Design Of The Anonymous Ftp Langley Technical Report Server, Michael L. Nelson, Gretchen L. Gottlich

Computer Science Faculty Publications

An experimental electronic dissemination project, the Langley Technical Report Server (LTRS), has been undertaken to determine the feasibility of delivering Langley technical reports directly to the desktops of researchers worldwide. During the first six months, over 4700 accesses occurred and over 2400 technical reports were distributed. This usage indicates the high level of interest that researchers have in performing literature searches and retrieving technical reports at their desktops. The initial system was developed with existing resources and technology. The reports are stored as files on an inexpensive UNIX workstation and are accessible over the Internet. This project will serve as …

World Wide Web Implementation Of The Langley Technical Report Server, Michael L. Nelson, Gretchen L. Gottlich, David J. Bianco

Computer Science Faculty Publications

On January 14, 1993, NASA Langley Research Center (LaRC) made approximately 130 formal, 'unclassified, unlimited' technical reports available via the anonymous FTP Langley Technical Report Server (LTRS). LaRC was the first organization to provide a significant number of aerospace technical reports for open electronic dissemination. LTRS has been successful in its first 18 months of operation, with over 11,000 reports distributed and has helped lay the foundation for electronic document distribution for NASA. The availability of World Wide Web (WWW) technology has revolutionized the Internet-based information community. This paper describes the transition of LTRS from a centralized FTP site to …

A Strategy For Electronic Dissemination Of Nasa Langley Technical Publications, Donna G. Roper, Mary K. Mccaskill, Scott D. Holland, Joanne L. Walsh, Michael L. Nelson, Susan L. Adkins, Manjula Y. Ambur, Bryan A. Campbell

Computer Science Faculty Publications

To demonstrate NASA Langley Research Center's relevance and to transfer technology to external customers in a timely and efficient manner, Langley has formed a working group to study and recommend a course of action for the electronic dissemination of technical reports (EDTR). The working group identified electronic report requirements (e.g., accessibility, file format, search requirements) of customers in U.S. industry through numerous site visits and personal contacts. Internal surveys were also used to determine commonalities in document preparation methods. From these surveys, a set of requirements for an electronic dissemination system was developed. Two candidate systems were identified and evaluated …

South Dakota Project P 0019(20)0 Pcems 238h Nebraska Project Stpd-57-4(108) Missouri River Bridge Near Vermillion Clay County, South Dakota Cedar And Dixon Counties, Nebraska, James Nelson, Arthur Yonkey, Lubin Quinones

United States Army Corps of Engineers, Omaha District

The South Dakota Department of Transportation (SDDOT) and the Nebraska Department of Roads (NDOR) propose to build a bridge over the Missouri River in the vicinity of Vermillion, South Dakota and Newcastle, Nebraska. (See Figure 1 for a computer image of this proposed bridge.) SO Highway 19, SO Highway 50 and Interstate 29 would connect with Nebraska Highway 12. The Nebraska approach roadway would be designed to provide two 3.6 meter (11.8-foot) driving lanes with 1.8 meter (6-foot) shoulders. The South Dakota inter-connecting roadway will be designed to provide two 3.6 meter (11.8-foot) driving lanes with two 3 meter (10-foot) …

Final Environmental Assessment For Endangered Species Habitat Improvement/Creation In The Missouri River Between The Niobrara River And Ponca, Nebraska

United States Army Corps of Engineers, Omaha District

An environmental assessment has been prepared for new habitat development in upper Lewis and Clark Lake and the Missouri River below Gavins Point Dam. The actions described are in response to the November 1990, U.S. Fish and Wildlife Service Biological Opinion on the operation of the Missouri River Main Stem System, and will provide safer nesting habitat for the interior least tern (endangered species) and the piping plover (threatened species).

Vegetation on the river islands will be removed and maintained in the "sparsely vegetated" state needed for nesting habitat for the terns and plovers. After vegetation removal, the islands will …

The Status Of Nebraska Fishes In The Missouri River. 6. Sauger (Percidae: Stizostedion Canadense), Larry W. Hease

United States Army Corps of Engineers, Omaha District

Saugers were once common representatives of the Missouri River fish assemblage. Prior to channelization and impoundment, they comprised from 10 to 65% of the main channel big-river fish group. They utilized the slower side channels and backwaters seasonally for feeding, resting, and maturing, but the main channel was important for breeding habitat, Since the onset of channelization and impoundment, saugers have been reduced by as much as 98% in some areas, and the trend toward extirpation continues unabated today. Recovery of native sauger stocks will require a complete cessation of harvest, recovery of the natural hydrograph, recovery of sediment transport, …

The Science Of Simulation Modeling, Paul Savory, Gerald Mackulak

Department of Industrial and Management Systems Engineering: Faculty Publications

Many people refer to simulation model building as an “intuitive art”. This implies that modeling can only be done by a select group of highly trained creative people and thus isolates many from considering simulation as a usable tool. Model building is a science that is learned through education, training and experience. In this paper, we discuss the role of science in performing a simulation study. We illustrate the teaching of the science of simulation by discussing the simulation curriculum at Arizona State University.

A Simplified Method For The Bilinear S-Z Transformation, Dan M. Scott

Department of Industrial and Management Systems Engineering: Faculty Publications

A new technique for performing the bilinear transformation of polynomials is presented. The technique is both simple to understand as well as efficient in its computer implementation. The key to the method is the way in which the successive derivatives of a particular polynomial are computed. A simple recursion formula is used which can be done either by hand, if desired, or by computer. The order of complexity of the algorithm is found to be O(n²), while storage requirements are O(n), where n is the degree of the polynomial. The new method will handle completely general …

Writing Across The Chemical Engineering Curriculum At The University Of North Dakota, Douglas K. Ludlow, Kirk H. Schulz

Chemical and Biochemical Engineering Faculty Research & Creative Works

In Order to Prepare Engineering Graduates with the Written and Oral Communication Skills Needed in their Professional Careers a Coordinated Writing Across the Curriculum (WAC) Program Has Developed in the Chemical Engineering Department at the University of North Dakota. the Students Practice and Develop their Skills with Writing Assignments in Both Lecture and Laboratory Courses from the First‐year Level through the Fourth‐year Capstone Design Course. the Coordinated Approach, especially in the Four‐semester Laboratory Sequence, Allows the Students to Develop their Skills by Building on Communication Experiences in Previous Courses. the WAC Program at UND Including Writing and Public Speaking Assignments …

Estimation Of Resilient Modulus Of Fine-Grained Subgrade Soils, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

The Role Of Component Packaging In System Electromagnetic Compatibility, Todd H. Hubing

Electrical and Computer Engineering Faculty Research & Creative Works

Increases in the speed and density of electronic systems do not necessarily result in tougher electromagnetic compatibility problems. In fact, recent advances in packaging technology can help designers to meet electromagnetic compatibility requirements. However, working with new technologies requires us to re-evaluate existing EMC design models and guidelines. Understanding the system-level impact of component-level packaging changes, is a prerequisite for meeting stringent electromagnetic compatibility requirements in a timely and cost-effective manner.

Determination Of Aashto Layer Coefficients For Granular Materials By Use Of Resilient Modulus, David Newton Richardson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The layer coefficients a₂ or a₃ for an unbound granular base or subbase material are found from a relationship with resilient modulus, E_b. The resilient modulus for a given material can be found by test using the "theta model" or by use of an estimation regression equation. E_b is a function of several factors, as discussed below.

Edge Strength Of Window Glass By Mechanical Test, Chris P. Pantelides, Gregory P. Sallee, Joseph E. Minor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A mechanical test is described that can be used to measure the edge strength of annealed and heat-strengthened glass. The mechanical test apparatus stresses only one of the two edge-lines on the edge of a glass specimen. The testing concept employs the theory of unsymmetrical bending. The test device loads glass specimens in a manner that places tensile stresses on the tested edge-line while keeping the other edge-lines at zero stress or in compression. In annealed glass tests, the scored edge-line was found to be 20% weaker than the edge-line opposite the scored edge-line. Comparisons between the edge strengths of …

Voltage Collapse. An Engineering Challenge, Mariesa Crow, Bernard C. Lesieutre

Electrical and Computer Engineering Faculty Research & Creative Works

Voltage collapse is characterised by a loss of control of the voltage levels in a power system. Although all of the precise mechanisms that affect voltage collapse have not yet been identified, voltage instabilities are known to occur when the power system is operating under a stressed state. The authors discuss voltage collapse and its relationship with the point of maximum power transfer and how voltage collapse can be better predicted

Effectiveness Of A Multimedia Televised Distance Education Program For Engineering Majors, Bonnie Daily, Madison Daily

Engineering Management and Systems Engineering Faculty Research & Creative Works

The University of Missouri‐Rolla, the state's, "technological university," has proposed a televised distance education program that would originate on the UMR campus and be delivered to community colleges and four‐year institutions within the state not now offering engineering. The program would include the use of computer‐integrated multimedia classrooms at both the home site and remote sites and would permit two‐way transmission of video, audio, and data. Student response units would also be used at both sites to permit immediate feedback from the students to the instructor. Due to the cost of this proposal, it was determined a pilot study would …

Ai-Based Generation Of Production Engineering Labor Standards, Hulya Yazici, Colin Othniel Benjamin, James Mcglaughlin

Engineering Management and Systems Engineering Faculty Research & Creative Works

Increased automation of manufacturing is necessary to compete in today's worldwide markets. The role of artificial intelligence (AI) techniques for incorporating the automation with changing manufacturing environments needs to be investigated. Al techniques can assist in meeting the challenge of transforming shop floor production engineering data into appropriate production engineering labor standards in a timely, consistent, and cost-effective manner. Production heuristics can be incorporated into an expert system that can learn from the changing manufacturing environment. This paper presents a prototype expert system which transfers the knowledge of experienced methods engineers into a rule-based system to develop the appropriate job …

Optimal Control Of Infinite-Order Smart Composite Structural Systems Using Distributed Sensors, Robert Butler, Vittal S. Rao

Electrical and Computer Engineering Faculty Research & Creative Works

In recent years there has been considerable interest in the design of spatially shaped distributed sensors for the control of infinite-order structural systems. The smart materials polyvinylidene fluoride (PVDF) and shape-memory alloys can be utilized in the development of customized distributed sensors. Sensor shape-optimization techniques are needed for the implementation of optimal control strategies. In this paper, a method for generating the shapes of distributed sensors using finite-dimensional approximations to desired curvature and curvature rate kernels is examined. The output of these spatially distributed sensors is utilized directly as the control signal for suppressing vibrations in infinite-order structural systems. This …

The Adaptive Control Of Smart Structures Using Neural Networks, Vittal Rao, Rajendra Damle, Chris Tebbe, Frank J. Kern

Electrical and Computer Engineering Faculty Research & Creative Works

The application of adaptive control algorithms for vibration suppression of smart structures is investigated in this paper. An accurate mathematical representation is not required in this approach. The controller adapts to the parameter variations of the structural system by updating the controller gains. When the desired performance of an unknown plant with respect to an input signal can be specified in the form of a linear or a non-linear differential equation, stable control can be achieved using model-reference adaptive control (MRAC) techniques. The conventional MRAC techniques have been successfully implemented on a smart-structure test article resulting in perfect model following. …

Programmable Analog Array Circuit, Marek Perkowski, Edmund Pierzchala

Electrical and Computer Engineering Faculty Publications and Presentations

There is disclosed a programmable analog or mixed analog/ digital circuit. More particularly, this invention provides a circuit architecture that is ?exible for a programmable electronic hardWare device or for an analog circuit Whose input and output signals are analog or multi-valued in nature, and primarily continuous in time. There is further disclosed a design for a current-mode integrator and sample-and-hold circuit, based upon Miller effect.

Neural Network Enhancement Of The Los Alamos Force Deployment Estimator, Bobby Turner, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

The Force Deployment Estimator (FDE) is a decision support system. It allocates transportation resources given inputs such as forces to be deployed and their desired arrival times. Other inputs are assumptions about conditions that affect performance: carrier start time, node capacity, sustainment shipping time, bulk sustainment per day, ammo sustainment per day, unit start time, carrier service time, carrier round trip time, and carrier reassignment time. Outputs include the mean and standard deviation of estimated unit arrival times versus goal times, and data files for post-processing. However, when a goal time is not met, the simulator gives no explanation of …

Microwave Diagnosis Of Rubber Compounds, Stoyan I. Ganchev, J. Bhattacharyya, Sasan Bakhtiari, Nasser N. Qaddoumi, Deborah Brandenburg, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

The results of a study investigating the dielectric properties of rubber compounds and their constituents in the frequency range of 5 to 24 GHz are presented. A completely filled short circuited waveguide technique was used to conduct these dielectric measurements. The influence of carbon black content in rubber was investigated for carefully prepared rubber samples. The results showed that for all frequencies, the dielectric constant increases as a function of increasing carbon black content. The variation of dielectric constant values decreases as frequency increases. The presence of curatives in uncured rubber samples was also detected, which indicates the sensitivity of …

Data-Feedthrough Faults In Circuits Using Unclocked Storage Elements, Waleed K. Al-Assadi, D. Lu, A. P. Jayasumana, Y. K. Malaiya, C. Q. Tong

Electrical and Computer Engineering Faculty Research & Creative Works

Some faults in storage elements (SEs) do not manifest as stuck-at-0/1 faults. These include data-feedthrough faults that cause the SE cell to exhibit combinational behaviour. The authors investigate the implications of such faults on the behaviour of circuits using unclocked SEs. It is shown that effects of data-feedthrough faults at the behavioural level are different from those due to stuck-at faults, and therefore tests generated for the latter may be inadequate

A Hierarchial Neural Network Implementation For Forecasting, B. Fulkerson, M. A. Ozbayoglu, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

In this paper, a hierarchical neural network architecture for forecasting time series is presented. The architecture is composed of two hierarchical levels using a maximum likelihood competitive learning algorithm. The first level of the system has three experts each using backpropagation and a gating network to partition the input space in order to map the input vectors to the output vectors. The second level of the hierarchical network has an expert using fuzzy ART for producing the correct trend coming from the first level. The experiments show that the resulting network is capable of forecasting the changes in the input …

A Comparison Of Fam And Cmac For Nonlinear Control, Arit Thammano, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This article compares a neural network-based controller, both local and global networks, with fuzzy associative memories (FAM) on a nonlinear problem. CMAC and FAM are chosen as representatives of local generalization networks. CMAC controller is trained off-line, therefore, it can response to the incoming input immediately. CMAC can interpolate its memory and give a reasonable control signal even the input has not been trained on. Backpropagation is picked as a representative of global generalization networks. All three systems are studied on a simple simulated control problem. This preliminary research will be adapted later to control the laser cutting machine. A …

The Integration Of Simulation And Reality For Education Enhancement And Training, Clarence Rasquinha, Stephen A. Raper

Engineering Management and Systems Engineering Faculty Research & Creative Works

Quite often, when engineers are exposed to a manufacturing environment on the job for the first time, they undergo a baptism by fire. The environment forces them to deal with situations that integrate many different bodies of knowledge. Reliance on concepts acquired in the academic environment is crucial to their success. Unfortunately, lacking in most academic environments, is any experience through which some or all of these concepts are integrated. In a continuing effort to enhance educational practices in Manufucturing/Systems Engineering programs and perhaps improve the preparedness of a young engineer, the CITE (Computer Integrated Technological Enterprise) tool offers educators …

Subgrade Resilient Modulus For Pavement Design And Evaluation : Implementation Report, Woojin Lee, Nihal Chand Bohra, A. G. Altschaeffl, Thomas D. White

JTRP Technical Reports

No abstract provided.

Estimating Statewide Vehicle Miles Traveled In Indiana : Draft Final Report, Robert Kwasi Kumapley, Jon D. Fricker

JTRP Technical Reports

Two cross classification models have been developed in this study for use in the estimation of statewide VMT in Indiana. This is to provide INDOT with an independent source of improved statewide VMT estimates based on driver behavior to supplement the estimates obtained from the traffic count based HPMS method. The models are calibrated to produce VMT estimates for all functional classes in the state network, including combined statewide VMT estimates for functional classes that are not part of the state highway system. The results obtained in the model evaluation process indicate that the models are well calibrated. Model-generated VMT …

The Computer Aided System For Planning Efficient Routes, J. R. Wright

JTRP Technical Reports

The Indiana Department of Transportation has sponsored the design and implementation of a decision support system for routing highway maintenance vehicles – the Computer Aided System for Planning Efficient Routes (CASPER). Designed for solving multiobjective route design problems, CASPER has been used by agency personnel to design routes for winter maintenance vehicles with significant results: cost savings of more than $9-million to the State of Indiana through more efficient use of materials, equipment, and personnel, while at the same time significant improvement in overall level of network and public service. CASPER integrates 1: an extensive spatial network database (GIS/CAD), 2) …