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1992

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Articles 1 - 30 of 1015

Full-Text Articles in Engineering

On Adaptive Censored Cfar Detection, Loizos Anastasiou Prastitis Dec 1992

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 ...


Analysis Of The Optimum Extraction System Design For The Separation And Purification Of Rare Earths, Kenneth Yeon-Kang Chan Dec 1992

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-H2O-TBP ...


Kinematic Synthesis Of Adjustable Four-Bar Mechanisms For Multi-Phase Motion Generation, Shao Jie Wang Dec 1992

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 ...


Investigation Of The Consumer Electronics Bus, Jaesoo Yang Dec 1992

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 ...


Investigation Of The Striation Formation In The Course Of Abrasive Waterjet Cutting, Jo-Fei Chao Dec 1992

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 ...


Trouble Shooting In Plastic Injection Molding Machines, Zafar Kamal Dec 1992

Trouble Shooting In Plastic Injection Molding Machines, Zafar Kamal

Theses

The purpose of this thesis is to find the solution of those problems which occur during plastic injection molding process. Molding cycle problem analysis is an important field in plastic injection process. It is very necessary to catch the problems during operation. Therefore on the basis of research trouble shooting criteria is prepared.

Good quality control is an essential feature for finding any sort of fault. Quality control is associated with each and every step of operation to maintain the required shape and surface finishing.

Most of the molding problems are solved by varying the machine conditions and by changing ...


Investigation Of Reactor Design Parameters Towards Optimizing Biodegradation Of Chlorophenols By Phanerochaete Chrysosporium, Nirupam Pal Dec 1992

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 ...


Study Of Surface Properties Produced By Magneto-Plasma On Nitriding For Improving Wear Resistance, I-Tsung Shih Dec 1992

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 ...


Simulation Study For The Effect Of Dependencies In Queueing Systems, Yitao Bai Dec 1992

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 Dec 1992

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.


Three Dimensional Magnetic Field Sensors And Array In Bicmos Technology, Bingda Wang Dec 1992

Three Dimensional Magnetic Field Sensors And Array In Bicmos Technology, Bingda Wang

Theses

This thesis presents new designs of three dimensional magnetic field sensors in BiCMOS technology. The detailed design of the merged structure device by common diffusion and the high gain transduction circuit are presented. The merged structure has the advantage of less area, less external contacts and less parasitic capacitance. Cross-sensitivity is also eliminated by employing the merged structure. Three active on-chip loads are introduced to improve the sensitivity. The SPICE simulation results show that when a relative change in current ΔI/I is 0.001, about 13.6 mV and 8.5mV can be detected at the output in X ...


Analysis Of A Band-Saw, Suat Ali Ozsoylu Dec 1992

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 ...


Method For Treating Rare Earth-Transition Metal Scrap, Frederick A. Schmidt, David T. Peterson, John T. Wheelock, Lawrence L. Jones Dec 1992

Method For Treating Rare Earth-Transition Metal Scrap, Frederick A. Schmidt, David T. Peterson, John T. Wheelock, Lawrence L. Jones

Iowa State University Patents

Rare earth-transition metal (e.g., iron) scrap (e.g., Nd-Fe-B scrap) is flux (slag) remelted to reduce tramp non-metallic impurities, such as oxygen and nitrogen, and metallic impurities, such as Li, Na, Al, etc., picked up by the scrap from previous fabrication operations. The tramp impurities are reduced to concentrations acceptable for reuse of the treated alloy in the manufacture of end-use articles, such as permanent magnets. The scrap is electroslag or inductoslag melted using a prefused, rare earth fluoride-bearing flux of CaF.sub.2, CaCl.sub.2 or mixtures thereof or the slag resulting from practice of the thermite ...


Nanosecond Transient Electroluminescene From Polymer Light-Emitting Diodes, David Braun, D. Moses, C. Zhang, A. J. Heeger Dec 1992

Nanosecond Transient Electroluminescene From Polymer Light-Emitting Diodes, David Braun, D. Moses, C. Zhang, A. J. Heeger

Electrical Engineering

The transient electroluminescence from polymer light-emitting diodes is reported. When the devices are mounted on a microstrip transmission line, the temporal response is limited by the electrode geometry, with rise and fall times below 50 ns. With low duty-cycle pulses (0.5%) the electroluminescence intensity remains proportional to the current at values up to 10 A/cm2, two orders of magnitude greater than possible under direct current operation. Since the spectral blue-shift observed at high current levels (with power dissipation above 1 W/cm2) indicates significant sample heating, still higher levels should be possible with proper thermal management.


Free-Radical Retrograde Precipitation-Polymerization Process, Gerard T. Caneba Dec 1992

Free-Radical Retrograde Precipitation-Polymerization Process, Gerard T. Caneba

Michigan Tech Patents

A free-radical retrograde polymerization process for forming a polymer. An admixture of reactants including predetermined amounts of a monomer, a solvent, and a free-radical-initiator is reacted. A precipitation polymerization reaction occurs such that a polymer-rich phase is at a temperature generally above the lower critical solution temperature (LCST) of the admixture.


Fuzzy Logic Applied To Adaptive Kalman Filtering, Marlys Rae Remus Dec 1992

Fuzzy Logic Applied To Adaptive Kalman Filtering, Marlys Rae Remus

Theses, Dissertations, and Student Research from Electrical & Computer Engineering

The Kalman filter provides an effective means of estimating the state of a system from noisy measurements given that the system parameters are completely specified. The innovations sequence for a properly specified Kalman filter will be a zero-mean white noise process. However, when the system parameters change with time the Kalman filter will need to be adapted to compensate for the changes. Traditionally this has been accomplished by using nonlinear filtering, parallel Kalman filtering and covariance matching techniques. These methods have produced good results at the expense of large amounts of computational time. Necessary changes in the system parameters become ...


Image Segmentation Using An Annealed Hopfield Neural Network, Yungsik Kim, Sarah A. Rajala Dec 1992

Image Segmentation Using An Annealed Hopfield Neural Network, Yungsik Kim, Sarah A. Rajala

Sarah A. Rajala

Good image segmentation can be achieved by finding the optimum solution to an appropriate energy function. A Hopfield neural network has been shown to solve complex optimization problems fast, but it only guarantees convergence to a local minimum of the optimization function. Alternatively, mean field annealing has been shown to reach the global or the nearly global optimum solution when solving optimization problems. Furthermore, it has been shown that there is a relationship between a Hopfield neural network and mean field annealing. In this paper, we combine the advantages of the Hopfield neural network and the mean field annealing algorithm ...


High-Level Expression Of A Heterologous Protein In The Milk Of Transgenic Swine Using The Cdna Encoding Human Protein C, William H. Velander, John L. Johnson, Raymond L. Page, Christopher G. Russell, Anuradha Subramanian, Tracy D. Wilkins, Francis C. Gwazdauskas, Christoph Pittius, William N. Drohan Dec 1992

High-Level Expression Of A Heterologous Protein In The Milk Of Transgenic Swine Using The Cdna Encoding Human Protein C, William H. Velander, John L. Johnson, Raymond L. Page, Christopher G. Russell, Anuradha Subramanian, Tracy D. Wilkins, Francis C. Gwazdauskas, Christoph Pittius, William N. Drohan

William H. Velander Publications

Transgenic pigs were generated that produced human protein C in their milk at up to 1 g/liter. The gene construct was a fusion gene consisting of the cDNA for human protein C inserted into the first exon of the mouse whey acidic protein gene. These results demonstrate that the mouse whey acidic protein gene contains regulatory elements that can direct cDNA expression at high levels in the pig mammary gland. Recombinant human protein C that was produced at about 380 pg/ml per hr in transgenic pig milk possessed anticoagulant activity that was equivalent to that of protein C ...


Method Of Predicting Cut-Time Of Milk Coagulum In Cheese-Making Process, Frederick A. Payne, Clair L. Hicks Dec 1992

Method Of Predicting Cut-Time Of Milk Coagulum In Cheese-Making Process, Frederick A. Payne, Clair L. Hicks

Biosystems and Agricultural Engineering Faculty Patents

An apparatus for predicting milk coagulum cut-time in a cheese making process includes a light source, a sensor or detector for sensing diffuse reflectance of light from said milk and a controller for analyzing the diffuse reflectance and accurately predicting the cut-time to significantly enhance overall yield. More specifically, the apparatus includes an optical probe which may be suspended over the milk or attached to a wall of a fermentation vessel in which the milk is contained. A method for predicting milk coagulum cut-time includes the steps of (a) directing light from a light source toward milk undergoing enzymatic hydrolysis ...


Utilizing Instructional Design Constructs To Enhance Computer-Based Instruction In Air Traffic Controller Training, Theodore Scott Rhoads Dec 1992

Utilizing Instructional Design Constructs To Enhance Computer-Based Instruction In Air Traffic Controller Training, Theodore Scott Rhoads

Theses - Daytona Beach

This study demonstrates that a computer-based instructional design format is appropriate for novice air traffic control (ATC) training. The computer presents the student with small amounts of information in tutorial and drill and practice sequences that necessitate student interactivity. The student is then periodically audit tested to ascertain mastery of the subject matter. The result of these mid-lesson evaluations serve as a self-check so that the student can assess his/her progress in the learning cycle. The systematic design of instruction and interactive approach to learning, enhances student motivation, improves learning and retention, while placing the responsibility of achieving specific ...


Active Vibration Control Device, Keith E. Rouch, Sanjiv Tewani, Bruce L. Walcott, Ted R. Massa, Robert W. Stephenson, L. Scott Stephens Dec 1992

Active Vibration Control Device, Keith E. Rouch, Sanjiv Tewani, Bruce L. Walcott, Ted R. Massa, Robert W. Stephenson, L. Scott Stephens

Mechanical Engineering Faculty Patents

An active vibration control device for controlling vibration in a cantilevered member and a method for the same are disclosed. The device is comprised of a cantilevered member having a longitudinal axis comprising a sensor mounted near the free end of the member to measure motion of the member in a transverse direction and to produce a corresponding signal. A force generating assembly is mounted to the member near the free end to oppose the measured motion with a force thereby minimizing subsequent motion along the transverse axis caused by vibration.


Semiconductor P-N Junction Space Charge Region Capacitance, Mohammad Humayun Habib Dec 1992

Semiconductor P-N Junction Space Charge Region Capacitance, Mohammad Humayun Habib

Dissertations and Theses

The classical capacitance voltage characteristics based on the depletion approximation, is adequate at reverse bias, but introduces errors at high forward bias. Because of its inherent simplicity and compactness this classical depletion model is well studied and widely used in circuit simulators. In this work, a new model for the semiconductor space charge region (SCR) capacitance, based on physical justification, will be derived. This new model takes three input parameters, C0 , Vbi and m, thus eliminating the fitting parameter FC currently used in SPICE. This new model is applicable for any applied voltage and will be compared with the SCR ...


The Role And Responsibility Of The Agricultural Professional In Promoting Farmers' Safety And Health, C. J. Lehtola Dec 1992

The Role And Responsibility Of The Agricultural Professional In Promoting Farmers' Safety And Health, C. J. Lehtola

Proceedings of the Integrated Crop Management Conference

Farmers indicate they expect and request farm safety services and information from the local farm chemical dealers. This workshop identifies agricultural hazards associated with crop production; e.g., tractors, machinery, and chemicals. Emphasis is placed on discussing the roles and responsibilities of the agricultural professional towards enhancing and promoting farmers' safety and health by means of various intervention strategies. Workshop participants will participate in group discussions in order to identify and recommend additional ways in which they can better serve their clientele in this crucial area.


Understanding And Reducing Pesticide Losses, James Baker, Ed Adcock, Gerald Miller Dec 1992

Understanding And Reducing Pesticide Losses, James Baker, Ed Adcock, Gerald Miller

Proceedings of the Integrated Crop Management Conference

A small portion of pesticides applied on farms inadvertently reaches surface and groundwater. The amount varies from nearly zero to sometimes more than 5 percent of the amount applied, depending on several factors discussed below. That may not seem like much, but a 1 percent loss of a 1-pound-per-acre pesticide application can contaminate all of the drainage from a field in a normal year at 5 parts per billion (ppb). This level can be of concern if the drainage water enters drinking water supplies. The U.S. Environmental Protection Agency has established Health Advisory Levels for most pesticides in drinking ...


Residue Management With Chisel-Type Implements, Richard Johnson Dec 1992

Residue Management With Chisel-Type Implements, Richard Johnson

Proceedings of the Integrated Crop Management Conference

Where chisels are improperly used, it may be difficult to end up with 30% surface cover. But by considering one or more of the following, 30 to 50% surface cover after planting should be possible:


Tillage Equipment Adjustment For Surface Residue, Mark Hanna Dec 1992

Tillage Equipment Adjustment For Surface Residue, Mark Hanna

Proceedings of the Integrated Crop Management Conference

Crop producers are increasingly interested in methods to manage higher levels of surface residue. Both economics and soil conservation are responsible for this attention. Six million additional Iowa acres will be shifted to a conservation tillage system during 1992-94 to comply with soil loss goals of the Food Security Act according to plans filed with the Soil Conservation Service. From a production cost viewpoint, fewer machine operations on the land lower input costs and increase net profit if output can be maintained.


Crop Residue Management- Part Of Farming In The Future, Jeffrey J. Zimprich Dec 1992

Crop Residue Management- Part Of Farming In The Future, Jeffrey J. Zimprich

Proceedings of the Integrated Crop Management Conference

Farming systems that manage crop residue are becoming more and more popular today. Interest and enthusiasm in crop residue management indicates that these farming practices will be part of farming in the future. Profit and conservation are driving these upward trends.


Guide To Revenue Calculations: Local Option Highway User Tax 1992, Jon D. Fricker Dec 1992

Guide To Revenue Calculations: Local Option Highway User Tax 1992, Jon D. Fricker

Indiana Local Technical Assistance Program (LTAP) Publications

This guide is provided to explain the output generated by the computer programs, and to suggest ways in which the results can be adapted to specific LOHUT proposals before a County Council. HERPICC neither endorses nor opposes passage of a LOHUT. The revenue projections it provides are intended to be an aid to well-informed decision-making on the part of a county’s citizens and its County Council.


Thermally Induced Vibration Of A Cross-Ply Laminated Plate With Hygrothermal Effects (Exact Solution), Stephen Jerry Maerz Dec 1992

Thermally Induced Vibration Of A Cross-Ply Laminated Plate With Hygrothermal Effects (Exact Solution), Stephen Jerry Maerz

Theses - Daytona Beach

Of increasing importance in structural design is the use of fiber-reinforced polymeric composite material, notably in advanced aircraft and projectiles. These applications expose the materials to varied environmental conditions, therefore the material performance under these conditions is of great interest. One aspect of this is the solution of the dynamic response of a composite structure under elevated temperature and moisture conditions. An exact solution is formulated which describes the hygrothermal effects due to heating and moisture diffusion on one surface of a symmetric cross-ply plate made of AS/3501 graphite epoxy with simply-supported boundary conditions.


Isolating Failure Mechanisms In A Fiberglass/Epoxy Tensile Test Specimen Using Acoustic Emission Signal Parameters, Michael Kouvarakos Dec 1992

Isolating Failure Mechanisms In A Fiberglass/Epoxy Tensile Test Specimen Using Acoustic Emission Signal Parameters, Michael Kouvarakos

Theses - Daytona Beach

This study used acoustic emission (AE) signal parameters to isolate the failure mechanisms in a 0° unidirectional, fiberglass/epoxy tensile test specimen. Since several failure mechanisms were known to be present, the lack of any distinctly identifiable bands in the original amplitude distribution indicated that there was considerable overlap between the AE signals of the various failure mechanisms. In order to separate the amplitude bands associated with each mechanism, it was necessary to sort on the duration of the AE signal. Two additional plots, counts versus amplitude and hits versus counts, were used to verify that the amplitude distributions were ...