Engineering Commons^™

Removal Of Gasoline-Based Hydrocarbons By Vapor Permeation Membranes, Shivashanker Bagavandoss

Theses

Removal and recovery of evaporated lighter gasoline fractions can be effectively implemented by selectively permeating the hydrocarbons (HCs) and other volatile organic compounds (VOCs) from the vented air streams through nonporous hydrophobic polymeric membranes subjected to vacuum on the permeate side and then condensing these organics from the permeate. Such a vapor permeation process employing spiral-wound membranes has already been commercialized for VOCs. In this study, attention has been focused on removal of hydrocarbons from nitrogen flowing through the bore of microporous hydrophobic hollow fibers with a specially engineered nonporous silicone coating on the outside surface with a view to …

Development Of A Gel Content Analysis Protocol For Ultra High Molecular Weight Polyethylene, Max Harold Jeanty

Theses

A modified procedure based upon ASTM (D 2765 - 90) to determine the gel content of crosslinked polyethylene plastics was developed. The new procedure was applied to ram extruded Ultra High Molecular Weight (UHMWPE) implant components processed under different manufacturing conditions. This new evaluation tool provides consistent results with greater accuracy and consistency compared to the American Society for the Testing of Materials (ASTM) method. Using the same tool, several relationships between the UHMWPE processing conditions and gel content were established. The amount of gel content is related to the crosslinked material. It has been shown that the more crosslinking …

Solidification/Stabilization Of Petroleum Contaminated Soils With Cold Mix Asphalt Concrete, Nazhat Aboobaker

Theses

In this research Petroleum Contaminated Soils (PCSs) are recycled in Cold Mix Asphalt (CMA), to produce a useful product that can control potential environmental threats. The stability, durability, and hydraulic conductivity are three important engineering parameters that need to be considered when using petroleum contaminated soils (PCSs) in cold mix asphalt (CMA). In this research, stability, durability, and hydraulic conductivity due to the addition of six different PCSs into CMA is investigated. The stability test were performed to determine if cold mix asphalt made with petroleum contaminated soil can withstand heavy traffic. The freeze-thaw, and wet-dry tests were performed to …

Modeling Of Cardiovascular System To Simulate Ventricular Septal Defect, Adarsh Kumar Gupta

Theses

The hemodynamics of the ventricular septa] defect is studied using a mathematical modeling technique. A twelve-compartment windkessel model of cardiovascular system is used to study the hemodynamics of the ventricular septal defect. The VSD is incorporated into the model via a parallel flow from the left to right ventricles (left-to-right shunt). The resistance to flow through the shunt is used to characterize the severity of the defect. Changes in the severity of the shunt flow produces changes in the ratio of pulmonary to systemic flow in the circulation. When the pulmonary to systemic flow ratio is more than 2:1, the …

Effect Of Lamellar Microstructure On The Permeability Of Polyethylene Films, Yufu Li

Theses

Lamellar microstructures can decrease the permeability to gases and vapors by increasing the diffusive path in plastic films, or the so-called "tortuosity" which depends on the aspect ratio, orientation, and the volume fraction of the dispersed material. In this research, different types and percentages of mica with relatively high aspect ratio are used as oxygen barrier materials in blown films. Both high and low density polyethylenes (HDPE and LDPE), as well as their blends are used as the matrix materials.

A decrease in permeability of both LDPE and HDPE films to oxygen is achieved with increasing volume fraction of the …

Implementation Of Fortran Finite Element Analysis Source Code With Application : Particle Deposition In A 90 Degree Duct Bend, Pantaleo Loiacono

Theses

Two FORTRAN 77 finite element analysis source codes, by 1.N. Reddy, were input into a PC, debugged, executed, and tested successfully. These programs are available to students interested in implementing a good finite element analysis source code on a PC or on a workstation in one or two dimensions. The programs can solve problems relating to heat transfer, stresses, beam analysis, frames, trusses, plane elasticity, plate bending, and laminar viscous incompressible fluids with various node and element combinations.

The two-dimensional program was used to obtain the velocity distributions in a 90 degree duct bend with incoming and exiting fully developed …

Fuel-Rich Combustion Of Ethylene And Air In A Two Stage Turbulent Flow Reactor, Tara Byrnes Salem

Theses

This thesis presents experimental and modeling results from the combustion of ethylene and air in a two stage turbulent flow reactor. This work is motivated by the continuing concern over combustion by-products. The first half of the research effort focused on the validation of the reactor as a perfectly stirred reactor and a plug flow reactor (PSR+PFR) sequence. Using four detailed reaction mechanisms, measured concentrations of carbon oxides, oxygen, and light hydrocarbon concentrations were modeled. Within the accuracy of the data, the mechanism of Mao (1995) yielded the best results. However, it was observed that the success of the reactor …

Fabrication Of Integrated Optic Sensor To Monitor Pollutant Concentration In Effluents, Kiran Chatty

Theses

An attempt has been made to fabricate an integrated optic sensor to monitor pollutant concentration in effluents. Optic fiber has to be coupled to the waveguide in order to send light through the waveguide. In order to facilitate the easy coupling of the fiber to the waveguide, V-grooves were formed in the silicon substrate. In order to achieve this Silicon nitride was deposited to serve as an etch mask. An attempt was made to obtain low stress silicon nitride films.

This work also attempted to synthesize the materials required to fabricate the waveguide. LPCVD processes were developed to produce undoped …

Synthesis And Characterization Of Silicon Dioxide Thin Films By Low Pressure Chemical Vapor Deposition Using Ditertiarybutylsilane And Oxygen, Sung-Jun Lee

Theses

This study is focused on the synthesis and characterization of silicon dioxide thin films deposited on silicon wafers by Low Pressure Chemical Vapor Deposition (LPCVD), using ditertiarybutylsilane (DTBS) as a precursor and oxygen as the oxidant. The dependence of film growth rate on various process parameters were studied. The growth rate was found to follow an Arrhenius curve with the variation in the temperature with an activation energy of 12.6 kcal/mol. The growth rate was found to be inversely proportional to the temperature in the range 550-750 °C. The refractive index and density were observed to be close to 1.47 …

Spice Compatible Equivalent Circuit Models Of Skeletal Muscle Tissue, Robert B. Szlavik, Hubert De Bruin

Biomedical Engineering

The authors present equivalent circuit models of skeletal muscle tissue for the directions parallel and transverse to the fiber. The parallel model is based on a distributed parameter equivalent circuit approach where the tissue between the electrodes is divided into small segments, each of which is represented by an equivalent circuit. Parameters for the equivalent circuits me calculated from the electrical characteristics of the tissue components and their physical arrangement. The authors compare the conductivity frequency response of the equivalent circuit modelling approach to other models presented in the literature. The advantage to the authors' equivalent circuit approach is that …

The In Vitro Evaluation Of Various Biodegradable Composites Used In Internal Fixation Devices, Hui-Chen Hsieh

Theses

In vitro degradation kinetics and mechanical properties of various composites, comprising a polycarbonate (DTE polymer) reinforced with CaP glass fiber, synthetic ceramic and non-ceramic hydroxyapatite (HA-500,OsteoGen HA) were investigated.

They were soaked in the SBF solution with a constant pH of 7.4 at 37°C for 5 days. The DTE/CaP composite degraded in an acid manner such that a large amount of NaOH was required but with a small decrease in calcium ion concentration. By contrast, the DTE/OsteoGen HA composite required comparable amounts of NaOH, but with a concomitantly large decrease in calcium ion concentration. This showed that the OsteoGen HA …

Adaptive Color Correlation Of Knots In Wood Images And Weighted-Value Product Selection Methods In A Machine Vision System, John Robert Goulding

Dissertations and Theses

The biggest obstacle to robust color image processing of wood is in developing a color model that represents all possible defect colors. When the color model is too general or too specific, defect recognition fails because too many or too few non-defect pixels match the model, respectively. Because a color image of wood contains far more clear and clear-grain colored pixels than grain-knot and knot colored pixels, it is beneficial to first statistically identify and remove the clear and clear-grain colors and to use the accumulated data to simultaneously enhance and normalize the remaining grainknot and knot colored pixels. This …

Visual Inspection Of New Ramp Pavement At Bluegrass Airport Lexington, Kentucky, David L. Allen

Kentucky Transportation Center Research Report

Personnel from the Kentucky Transportation Center performed a visual inspection of newly constructed ramp pavement at the Bluegrass Airport in Lexington, Kentucky. The inspection was conducted in May, 1996 at the request of airport engineers. The inspection revealed a number of concrete apron slabs that had cracked. Attempts had been made (apparently by the contractor) to seal the cracks by epoxy injection. The visual inspection indicated that the epoxy may not have been performing as hoped, and that some of the cracks did not appear to be sealed. As a result, it was decided to obtain cores of the cracked …

Optical Detection Properties Of Silicon-Germanium Quantum Well Structures, Michael R. Gregg

Theses and Dissertations

A study has been carried out on Si/SiGe multi quantum well structures to determine their applicability as normal incidence infrared detectors in the spectral range of 2-12 micrometers. The research effort was primarily experimental; however, extensive calculations were performed to initially explain the experimental data and then used to design subsequent structures. Multiple quantum well structures grown on both Si[001] and Si[110] substrates via molecular beam epitaxy were studied by photoluminescence, absorption, and photoresponse measurements over a wide parameter space. Variables included quantum well depth and width, well doping, number of wells and growth temperature. Well widths were varied from …

Effect Of Bracing Stiffness On Buckling Strength Of Cold-Formed Steel Columns, Pratyoosh Gupta, George E. Blandford, S. T. Wang

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A three-dimensional second-order analysis is used to study the effect of brace stiffness on the buckling strength of cold-formed steel columns. The finite element formulation uses an iterative updated Lagrangian scheme to include the second-order geometric non-linear effects in the space frame element as well as the connection element used to model a brace. Lateral brace stiffness required to achieve full bracing for a two-dimensional column, and lateral and torsional brace stiffnesses required for a three-dimensional cold-formed steel column are studied. The strength requirement for various brace components, the effects of column initial imperfections, and the impact of varying warping …

Interaction Of Flange/Edge - Stiffened Cold Formed Steel C - Sections, Colin A. Rogers, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A revision to the Canadian Standard (S136-94)[1] and the American Specification (AISI- 89)[2], in which the procedure to calculate the effective width of an edge-stiffened compressive flange is modified, has been proposed by Dinovitzer et al.[3]. The proposal involves a change of the equations for the flange plate buckling coefficients of Case II compressive elements, which eliminates a discontinuity in the effective width formulation. The modified local buckling procedure was compared with the current Canadian Cold Formed Steel Standard using a program of beam tests at the University of Waterloo[4] and data available in the literature[8,9, 10, 11,12]. Statistical results …

A New Aisi Cold-Formed Steel Design Manual, Richard C. Kaehler, Paul A. Seaburg

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The Specification Committee of the American Iron and Steel Institute is currently developing a new Cold Formed Steel Design Manual. The work is being done under contract with Computerized Structural Design with oversight provided by AISI Subcommittee 26 - Design Manual. This paper describes the purpose and contents of this Manual. It is expected the Manual will be published in conjunction with the new edition of the Specification for the Design of Cold-Formed Steel Structural Members early in 1997. The Manual will contain the combined versions of the Allowable Stress Design and Load and Resistance Factor Design Specifications in addition …

Performance Of Self-Tapping Screws In Lap-Shear Metal-To-Metal Connections, Reynaud Serrette, Victor Lopez

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The basic design requirement for screws in light gauge steel construction is the strength of the screw in a given application (metal-to-metal, wood-to-metal, or metal-to-wood) based on the body diameter of the screw. This statement is clearly obvious from the current AISI screw specifications for lap shear metal-to-metal connections. Recent research has shown that the performance of a screw fastener may also depend on other features of the screw including the head and thread style, and the method of installation (stripped versus unstripped screws). The data presented in this paper address these issues for lap shear connections designed with No. …

Cold Formed Steel Flat Width Ratio Limits, D/T And DI/W, Colin A. Rogers, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper reports the findings of an investigation of the flat width ratio limit for simple edge-stiffeners of channels in bending. Willis & Wallace concluded that the lip flat width ratio limit, d/t, should have a value of 14 based on a comparison of the 1980 and 1986 editions of the American Iron and Steel Institute (AISI) Cold Formed Steel Specification. This conclusion was made using the results of only three channel beam tests with various lip sizes, Case III flanges and locally unstable webs. The CAN/CSA-S136 Technical Committee adopted the recommendations of Willis & Wallace and included the lip …

Structural Design Study On A Light - Gauge Steel Portal Frame With Cold-Formed Sigma Sections, Pentti Makelainen, Juhani Kankaanpaa

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Design study is conducted on a thin-gauge cold-formed steel portal frame with compound double (back-to-back) sigma sections in columns and rafters. Experimental study on the sem-irigid rafter-to-column connection behaviour is first carried out for two special bolted connection types based upon specific thin connection plates between the double sections. First connection plate studied was a compact corner plate bolted between double sigma sections of rafter and column end parts. Other connection plate type studied was composed of four together layered thin plates with the edges of two outer plates outwardly lipped at the free side of the corner plate. Connection …

Moment Rotation Behavior For Concrete Filled Shs Column To Composite Beam Connections, J. S. Lee, Young Bonb Kwon, K. S. Woo

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

A series of connection tests were carried out to study the behavior of connections between concrete filled Square Hollow Section(SHS) columns and composite W-section beams. The test connections were four different semi-rigid types selected for application to multi -story building frames. The initial flexural rigidities were estimated by different theories and compared with the simple beam. Moment-roration relations were simulated using a finite element program and a simple power model was proposed to predict the moment-rotation behavior of connections.

Strength And Stiffness Calculation Procedures For Composite Slabs, Budi R. Widjaja, Samuel W. Easterling

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Two procedures for calculating the strength and stiffness of composite slabs based on a partial interaction model are introduced. The procedures rely on elemental test results for interfacial and end-anchorage behavior, and thus offer an alternate solution to the m and k method that relies heavily on full scale slab tests. Strength calculations made using the new procedures along with calculations from the Steel Deck Institute procedure are compared to a series of full size composite slab test results.

Strength Of Headed Shear Studs In Cold-Formed Steel Deck, John C. Lyons, Samuel W. Easterling, Thomas M. Murray

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

Results from 57 push-out tests of headed shear studs in cold-formed steel deck are presented. The results are compared to predicted strengths using the American Institute of Steel Construction Load and Resistance Factor Design Specification. The results indicate that the AISC specification does not accurately predict the strength of the shear studs placed in steel deck.

Residential Applications Of Cold-Formed Structural Members In Australia, Gregory J. Hancock, Thomas M. Murray

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The design of steel framed houses in Australia is governed by a range of Australian Standards covering materials, strnctural design and performance and loading. The paper describes these standards and their applicability. Innovative building systems using high strength steel have recently been introduced into the residential construction market in Australia. A brief description of the members used in these systems is provided. The National Association of Steel Framed Housing (NASH) promotes the use of steel in homes and provides educational material to assist builders, suppliers, teachers and students.

Steel - The Clear Cut Alternative, Richard Haws

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The current use of cold-formed steel owes its success to efforts which started 50 years ago. In 1946 AISI published the first specification for the design of cold-formed (then known as light gage) steel structural members. The specification was the end product of a doctoral thesis by Dr. George Winter which was initiated in 1939. Since 1946 AISI has continually updated and modernized the AISI Specification for the Design of Cold-Formed Steel Structural Members. The 1956 manual was the first design specification to have a companion commentary. In 1991 AISI published the LRFD version of the Design of Cold-Formed Steel …

A Study On The Effect Of Cold Forming On The Yield Strength Of Stainless Steel Type 304 - Hardness Test Approach, M. Macdonald, J. Rhodes, M. Crawford, G. T. Taylor

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

This paper describes a preliininary experimental investigation of the effects of cold forming on the material properties of stainless steel comer sections. The background and theory behind the research is briefly reviewed and is followed by a description of hardness testing. Hardness testing is used to postulate values for the increase in yield strength around the comers. The experimental findings are presented and the postulated increases in yield strength are compared with those predicted by two existing theories, and by other experiments carried out by the authors. It is concluded that the linear relationships found between yield strength and hardness …

An Explicit Approach To Design Of Stainless Steel Columns, Jacques Rondal, Kim J. R. Rasmussen

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The paper describes a design procedure for stainless steel columns failing by flexural buckling. In the approach, the stress strain-curve is assumed to be expressed as a Ramberg-Osgood curve, defined in terms of the initial modulus (Eâ‚€), the 0.2% proof stress (σ₀.â‚‚) and the parameter n. It is shown that the column curve can be described in terms of the Ramberg-Osgood parameters by adopting a Perry-curve as basic strength curve and expressing the imperfection paranleter in terms of Eâ‚€, σ₀.â‚‚ and n. By using a Perry-curve, the design procedure is explicit. This contrasts the iterative approach described in the ASCE-LRFD …

The Strength Of Partially Stiffened Stainless Steel Compression Members, W. Reyneke, G. J. Van Den Berg

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

In this study the effect of the non-linear behaviour of stainless steels on the local buckling strength of partially stiffened compression elements is studied. The steel under investigation is a Type 304 stainless steel. Doubly symmetric hat section columns were manufactured by a press braking process and tested as stub columns to exclude overall buckling interaction. The different plasticity reduction factors' suggested in the ASCE stainless steel design specification for stiffened and unstiffened compression elements are used to compare experimental results with theoretical predictions. It is concluded that the ASCE and South African stainless steel design specifications overestimate the local …

Effective Width Of A Simple Edge-Stiffener Subjected To A Stress Gradient, Colin A. Rogers, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The most recent editions of the North American Design Standards present a unified effective width approach for the design of compressive elements. This paper outlines a comparison of various modifications to the existing procedure used to calculate the effective width of a simple edge-stiffener subjected to a stress gradient. The comparison involves three methods where the magnitude of the compressive stress is altered, and two stress gradient methods where the plate bucking coefficient is based on the ratio of compressive stresses at the top and bottom of the flat width of the simple edge-stiffener. Analysis of these methods was carried …

Design Of Thin-Walled Beams For Distortional Buckling, C. Jiang, J. Michael Davies

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

The bending behaviour of cold-formed steel beams is far from simple. The double symmetry associated with hot-rolled I-sections is generally uneconomical and the use of thin-walled slender elements means that local buckling of parts of the cross-section in compression may be a significant design factor leading to additional asymmetry of behaviour. Furthermore, the modern tendency to introduce additional folds in order to control local buckling and to produce more favourable global section properties also serves to aggravate the tendency towards distortional buckling. Generalised Beam Theory (GBT) has wide application to the analysis and design of cold-formed beams and can provide …