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Portland State University

Theses/Dissertations

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Articles 601 - 623 of 623

Full-Text Articles in Engineering

The Development And Testing Of A Fluidic/Pneumatic Position Servo, David Lyle Portin Jan 1977

The Development And Testing Of A Fluidic/Pneumatic Position Servo, David Lyle Portin

Dissertations and Theses

This thesis reviews the design and analysis of a fluidic pneumatic position servo. Rolling diaphragm piston actuators are used for the system drive, and a hydrostatic gas journal bearing is used as the position sensor. The servo has a 1 inch range which is monitored using an electrical capacitive position transducer that was built as an integral part of the system.

Open-loop frequency response testing provides the basis for a mathematical model of the system.

The servo response is linear at frequencies up to 3 Hertz.

The frequency response appeared to be limited by the design of the gas bearing ...


A Numerical Solution For The Ultimate Strength Of Tubular Beam-Columns, Arnold L. Wagner Nov 1976

A Numerical Solution For The Ultimate Strength Of Tubular Beam-Columns, Arnold L. Wagner

Dissertations and Theses

To provide a basis for the development of interaction curves for tubular beam-columns of annular cross section, a general purpose beam-column computer program is developed, and used to determine ultimate load capacities. The paper presents the analytical model and the computer method. The analytical results are compared with published test data as well as experimental data obtained as part of this project.


A Study On The Stabilization Of A Floating Platform, Waldo Lizcano Jul 1976

A Study On The Stabilization Of A Floating Platform, Waldo Lizcano

Dissertations and Theses

A new technique for controlling the pitching motion of a floating platform is proposed in this study.

The floating platform is assumed to be a simplified model of the columnar type rectangular platform supported by buoyant force from four cylindrical legs. The control arrangement consists of water jet streams immerging horizontally from two points located some distance apart on each leg to form a restoring couple. The water jet streams can be shifted t0 opposite horizontal positions or to the vertical downward ,positions according to control requirements. They are governed by angle control criterion as well as velocity control criterion ...


The Analysis Of The Deflection And Containment Of A Hot Plume By Side Draft Exhaust Hooding, Douglas H. Macgowan May 1976

The Analysis Of The Deflection And Containment Of A Hot Plume By Side Draft Exhaust Hooding, Douglas H. Macgowan

Dissertations and Theses

A common industrial ventilation and pollution problem results when a thermally buoyant polluted plume of air must be exhausted away from a work area to allow achievement of air pollution standards. Generally, a close fitting canopy hood is one of the most effective means of exhaust containment; however, physical restrictions or the operation itself often prevent such an arrangement, and a hood located to the side of the operation is required. This arrangement requires the exhaust to bend and contain the vertically rising plume with a horizontal sweep of exhaust air across the surface of the operation.

A review of ...


The Design Of An Automatic Electronic Preanodizer, Armen C. Grossenbacher Jan 1976

The Design Of An Automatic Electronic Preanodizer, Armen C. Grossenbacher

Dissertations and Theses

The topic of this thesis is the design of an automatic preanodizer to be used to preadjust precision tantalum resistors by anodizing their surfaces. The purpose of the preanodizer is to generate a controllable voltage ramp to be applied to a set of tantalum resistors which are immersed in a suitable electrolyte. The slope and maximum value of the voltage ramp are set to produce the current required for proper anodization of the resistors. The rate of anodization determines the rate of change of the resistor value. This thesis covers the design of an electronic device to meet a set ...


Evaluation Of The Institute Of Transportation Engineers Program For School Pedestrian Crossing, Nabil S. Hamadeh Jan 1976

Evaluation Of The Institute Of Transportation Engineers Program For School Pedestrian Crossing, Nabil S. Hamadeh

Dissertations and Theses

The Technical Council of the Institute of Transportation Engineers (ITE) developed a program f or school crossing protection. The intent of this thesis is to evaluate the ITE program within. the context of those programs developed by other agencies throughout the nation. Research materials were obtained from the appropriate Federal, state, local and other agencies through papers, articles, reports and correspondence. Upon the analysis of these sources, the ITE program was found to be deficient in several ways. Recommendations for modifying the program which are set forth herein include a revision of the ITE program including the school route map ...


Design Of A Microprocessor Controlled Telecommunication System, George J. Maroutsos Jan 1976

Design Of A Microprocessor Controlled Telecommunication System, George J. Maroutsos

Dissertations and Theses

Recent advancements in Large Scale Integration Technology have made available devices, such as microprocessors, analog gates and “three state” logic, that provide the designer with a wide range of possibilities in the design of telecommunication systems. A microprocessor and analog gates are utilized in this design to demonstrate the feasibility of implementing a flexible Telecommunication System. The microprocessor is programmed to control, through software, the system functions. The feasibility of systems highly adaptable to the needs of individual subscribers is thus demonstrated.


Computer Aided Design For Fluidic Sequential Circuits Of Fundamental Mode, Yau-Hwang Lee Jul 1975

Computer Aided Design For Fluidic Sequential Circuits Of Fundamental Mode, Yau-Hwang Lee

Dissertations and Theses

This thesis presents the method of state diagram synthesis and the development of a computer program for designing fluidic sequential feedback • control circuits of the fundamental mode. A paper on state diagram synthesis was authored by Chen and Lee, presented in Detroit and published as ASME paper 73-WA/Flcs-2 in 1973. Hypothetical systems are illustrated by using series of events characterized by the piston positions of some double-acting pneumatic cylinders. In these systems , an action can only begin when the previous action has been completed. Every extension or retraction of a piston is memorized and manifested by a flip-flop element ...


The Digital Multifunction Power Measuring System, Ralph Warren Shoemaker May 1974

The Digital Multifunction Power Measuring System, Ralph Warren Shoemaker

Dissertations and Theses

The Digital Multifunction Power Measuring System is the outgrowth of a project involving the design of a prototype precision Digital Watt Transducer for the Bonneville Power Administration (BPA). A prototype Digital Watt Transducer was built and tested since no other device of the desired accuracy was connnercially available. Upon partial completion of the project, another Watt Transducer did become available which was essentially identical to our development. Since we could not economically compete with the manufacturer of these Watt Transducers, our project was stopped. Over a period of several months we thought about other ways to apply the experience gained ...


Optimization Of Single- And Double-Flash Cycles And Space Heating Systems In Geothermal Engineering, Talal Hussein Hassoun Jan 1974

Optimization Of Single- And Double-Flash Cycles And Space Heating Systems In Geothermal Engineering, Talal Hussein Hassoun

Dissertations and Theses

Two different problems of optimization in the utilization of geothermal energy are presented: First, the thermodynamic optimization for a geothermal power plant using a single- or double-flash process is considered; in this analysis, the optimum flash temperature giving the maximum power output is determined. Second, an economic optimization for space heating systems using geothermal energy is developed to obtain operating conditions for which the total (capital and operating) cost is a minimum.

Both graphical and analytical methods are used in the thermodynamic optimization to determine the optimum flash temperature. The graphical method is based on thermodynamic data provided by an ...


An Automatic Rinse Tank Controller For Industrial Applications, Aliasghar Emami Jan 1974

An Automatic Rinse Tank Controller For Industrial Applications, Aliasghar Emami

Dissertations and Theses

This thesis describes an automatic Rinse Tank Control System used in detection and removal of contaminating agents from industrial plating rinse tanks. It automatically monitors the purity of the rinse water in sixteen separate rinse tanks, and permits fresh water to enter the tanks only when the conductivity of the rinse water in each tank exceeds a predetermined level. Its use will result in large savings in consumption of fresh water and the subsequent reduction in discharge of effluent to the treatment plants.


Recent Developments In The Use Of Precast Concrete Units For Buildings In The United States And Iran, Khosrow Ebadi Farshchi Aug 1973

Recent Developments In The Use Of Precast Concrete Units For Buildings In The United States And Iran, Khosrow Ebadi Farshchi

Dissertations and Theses

The object of this study was to investigate the recent developments in the use of precast prestressed concrete members for buildings in the United States and Iran. In the United States, the study was concerned with developments in the usage of members such as slabs, wall panels, beams and columns. The latest technical and engineering reports, along with personal interviews, were used, and a number of case studies were conducted on recently built structures. The author also studied the newest developments in the precast concrete industry in Iran. A questionnaire was formulated in both Persian (native language of Iran) and ...


Response Of Orthotropic Bridge Decks To Highway Loadings, Harry Morris Rexin Jul 1973

Response Of Orthotropic Bridge Decks To Highway Loadings, Harry Morris Rexin

Dissertations and Theses

This thesis documents the fabrication, testing techniques, and response of a plastic scale model of an orthotropic bridge deck. To economically investigate a two-lane steel bridge deck, plastic AcrylicR was used as a modeling material. Welds were simulated with dichloromethane, a capillary action solvent, and PS-30, a polymerizable cement. Deflections were measured with laboratory dial guages while strains were monitored with strain guages mounted on the deck.

The response of the deck to AASHO vehicle axle loads was compared with a discrete element computer program used to analyze orthotropic bridge decks continuous over flexible supports. Results indicate good correlation ...


Digital Computer Solution Of Electromagnetic Transients In Large Power Systems, Bijan Navidbakhsh May 1973

Digital Computer Solution Of Electromagnetic Transients In Large Power Systems, Bijan Navidbakhsh

Dissertations and Theses

This thesis is an introduction to the solution of electromagnetic transients by a combination of the Bergeran method of characteristics and the application of trapezoidal rule of integration.

Three test examples solved by digital computer illustrate the step by step solution and computer programming. To compare this method with the Laplace transformation technique, a test problem solved by both methods and also digital computer is illustrated. In conclusion, the advantages and disadvantages of both methods are compared


The Random Sequence Closing Control System, Henri Bernard Joyaux May 1973

The Random Sequence Closing Control System, Henri Bernard Joyaux

Dissertations and Theses

This thesis describes a digital control system used by the Network Analog Group of the Bonneville Power Administration. This system, the Random Sequence Closing Control System, provides automatic control for a special purpose analog computer used in the study of switching surge over voltages on power transmission lines. This system, which uses pseudorandom data, has made it feasible to analyze switching surge phenomena on a statistical basis.


Moment-Curvature-Thrust Relationships In Hybrid Members, Douglas Wrenn Fiala Jul 1972

Moment-Curvature-Thrust Relationships In Hybrid Members, Douglas Wrenn Fiala

Dissertations and Theses

In order to overcome the difficulties encountered in closed form solutions, moment-curvature-thrust relationships are developed for hybrid and nonhybrid cross sections utilizing an open form method. The use of horizontal sectors permits the inclusion of residual stresses and/or nonbilinear stress-strain relationships, if desired. Theoretical and experimental data are compared. Applications to circular tubes and other cross sections are discussed. Results indicate that open form solutions are feasible for calculating moment-curvature-thrust data. Hybrid cross sections are easily treated by open form solutions.


Entropy Reduction Of English Text Using Variable Length Grouping, Vincent Norman Ast Jul 1972

Entropy Reduction Of English Text Using Variable Length Grouping, Vincent Norman Ast

Dissertations and Theses

It is known that the entropy of English text can be reduced by arranging the text into groups of two or more letters each. The higher the order of the grouping the greater is the entropy reduction. Using this principle in a computer text compressing system brings about difficulties, however, because the number of entries required in the translation table increases exponentially with group size. This experiment examined the possibility of using a translation table containing only selected entries of all group sizes with the expectation of obtaining a substantial entropy reduction with a relatively small table. An expression was ...


Studies Of Bistable Fluid Devices For Particle Flow Control, Gerald H. Hogland Feb 1972

Studies Of Bistable Fluid Devices For Particle Flow Control, Gerald H. Hogland

Dissertations and Theses

This study was directed toward the development of a bistable wall attachment Flip-Flop device which was capable of directionally controlling particle flow. The particles were transported by a fluid stream which under the influence of wall attachment. The dominant criteria in the development of the device was the achievement of the highest recovery of particles at the active output, without destroying the wall attachment of the fluid stream The experiment was conducted in several distinct stages; each of which was concerned with at least one aspect of wa1l attachment or particle flow. Results derived from one test were used to ...


Saddas; A Self-Contained Analog To Digital Data Acquisition System., Walter Anton Petersen Jan 1972

Saddas; A Self-Contained Analog To Digital Data Acquisition System., Walter Anton Petersen

Dissertations and Theses

SADDAS, a. Self-contained Analog to Digital Data Acquisition System, converts analog voltage inputs to formatted BCD (binary coded decimal digital magnetic tape. SADDAS consists of a 16 channel multiplexer, a 17 bit (4 digits + sign) 40 microsecond analog to digital converter, a 512 byte 8 bit core memory, a 30 IPS (inches per second) digital tape recorder at a density of 556 cpi (characters per inch), and a controller which integrates these instruments into a flexible and easy-to-use system. Sampling rates in excess of 360 samples per second may be used when converting seven channels of data, such as IRIG ...


Comparative Study Of Lightweight And Normal Weight Concrete In Flexure, Mohammad Zareh Jan 1971

Comparative Study Of Lightweight And Normal Weight Concrete In Flexure, Mohammad Zareh

Dissertations and Theses

This investigation represents a comparative study of the flexural behavior of lightweight and normal weight concrete. Both theoretical and experimental moment-curvature characteristics of the tested specimens were used to study the flexural behavior. A generalized computer program to determine the moment-curvature relationships of a singly reinforced rectangular concrete beam was developed. For this limited study it was observed that lightweight concrete beams when compared to normal concrete beams achieve comparable moment capacity (about 92% of normal weight concrete) but exhibit higher deflections (about 40% more than normal weight concrete).


Direct Design Of A Portal Frame, Angel Fajardo Ugaz Jan 1971

Direct Design Of A Portal Frame, Angel Fajardo Ugaz

Dissertations and Theses

This investigation was undertaken to develop plastic design aids to be used in the direct design of optimum frames. It uses the concept of minimum weight of plastically designed steel frames, and the concept of linear programming to obtain general solutions. Among the special characteristics of this study are: A. The integration of both gravity and combined loading conditions into one linear programming problem. B. The application of the revised simplex method to the dual of a parametric original problem. C. The application of A and B above in the development of design aids for the optimum design of symmetrical ...


Computer Solution To Inverse Problems Of Elliptic Form: V²U(X,Y)=G(A,U,X,Y), Frederick Alvin Jeter Jan 1971

Computer Solution To Inverse Problems Of Elliptic Form: V²U(X,Y)=G(A,U,X,Y), Frederick Alvin Jeter

Dissertations and Theses

One important aspect of our present age of monolithic high speed computers is the computer's capability to solve complex problems hitherto impossible to tackle due to their complexity. This paper explains how to use a. digital computer to solve a specific type of problem; specifically, to find the inverse solution of a in the elliptical equation V2U(x,y) = g(a,U,x,y), with appropriate boundary conditions. This equation is very useful in the electronics field. The knowns are the complete set of boundary values of U(x,y) and a set of observations taken on ...


Systems Reliability Using The Flow Graph, Kenneth Edward Farrier Jan 1970

Systems Reliability Using The Flow Graph, Kenneth Edward Farrier

Dissertations and Theses

The problem of calculating the reliability of a complex system of interacting elements is delineated to a linear system, no element of the system having a reliability distribution in terms of any other e1ement of the system, where only one path is taken through the system at a time. A precise definition is then developed to specify the reliability of the linear, single path at a time, system. A precise and concise generating function is found that effortlessly produces the reliability of the linear, single path at a time, system directly from the reliability flew graph of the system.