Engineering Commons^™

A Dynamic Programming-Based Approach To Microarray Image Comparison And Registration, Sunil Bosco Rodrigues

Masters Theses

"Microarray technology is increasingly used as a means of high throughput analysis of human, non-human and plant genomes. Manual methods of array production have inherent imperfections and variations of the quality of output data derived from these arrays. A dynamic programming-based approach is presented to validate the quality of such data prior to insertion into evolving databases in order to assign reliably, genetic aberrations to bio-medical functions. Dynamic programming is used for comparing normal and tumor microarray image pairs and a cost function is developed which gives a value representing the difference between the images. Quality of the image pairs …

Corrosion Of Galvanized Fasteners: Appendix, Steel Framing Alliance

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Design Methods For Auger Cip Piles In Compression, Giuliana A. Zelada, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This Paper Reports on a Study of 43 Compression Load Tests (Five Fully Instrumented) and Ten Pullout Tests of Auger Cast-In-Place (ACIP) Piles in Sand. Eight Design Methods Reported in the Literature Were Used to Predict the Measured Pile Capacities. Ultimate Load Capacities of the ACEP Load Tests Were Determined using Two Different Definitions of Ultimate Capacity and Compared with Predictions. Load Transfer Behavior Was Determined from a Study of the Fully Instrumented Pile Tests and Compared to Predicted Values. Recommendations Are Made Regarding the Design Approach Most Appropriate for These Foundations and the Best Procedure for Estimating Ultimate Capacity …

Novel Processing Of Hydroxyapatite-Zirconia Composites Using Nano-Sized Particles, Mark R. Towler, I. R. Gibson, S. M. Best

Chemical and Biochemical Engineering Faculty Research & Creative Works

A method to produce composites of hydroxyapatite (HA) with ZrO2 (Y-TZP) additions between 0 and 10 wt % at a low sinter temperature of 750 °C is presented. The method limits the amount of reaction between the HA and ZrO2. A ZrO2 loading level that would improve strength while limiting the decomposition of the HA is studied.

Simplified Window Glass Design Procedure, H. Scott Norville, Joseph E. Minor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a simplified window glass design procedure (SWGDP) as an alternative to the comprehensive window glass design procedure described in ASTM E 1300, `Standard practice for determining the load resistance of glass in buildings.' Although ASTM E 1300 provides a technically robust treatment of the strength of window glass and window glass constructions, architects and engineers will find ASTM E 1300 difficult to use. The SWGDP presented herein uses the same failure prediction methodology to characterize the annealed window glass strength that underlies ASTM E 1300. By reducing the number of basic glass strength charts to one, the …

Electrical Conductivity Of Nanocrystalline Ceria And Zirconia Thin Films, Igor Kosacki, Toshio Suzuki, Vladimir Petrovsky, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The results of studies of the preparation, structure and electrical conductivity of ZrO₂:16% Y and CeO₂ thin films are presented. Dense films with grain size controlled in the region of 1-400 nm have been obtained on monocrystalline sapphire and polycrystalline Al₂O₃ substrates using a polymeric precursor spin coating method. The electrical conductivity of nanocrystalline thin films has been studied as a function of oxygen activity and temperature and correlated with the microstructure. Nanocrystalline specimens are characterized by enhanced electrical conductivity and different stoichiometry compared with microcrystalline material.

Voltage Stability Analysis: V-Q Power Flow Simulation Versus Dynamic Simulation, Badrul H. Chowdhury, C. W. Taylor

Electrical and Computer Engineering Faculty Research & Creative Works

Several analysis methods are available for long-term voltage stability. The V-Q curve power flow method is widely used by Western Systems Coordinating Council utilities, and has some advantages. Long-term dynamic simulation with proper modeling, however, is clearly the most accurate simulation method. The authors compare the two methods for wintertime voltage stability problems in the Portland, Oregon, USA, load area. Results from the V-Q method can be misleading. The same is true of other power flow program based analysis employing conventional modeling. Results from these power flow methods may be pessimistic, causing overdesign or overly conservative operation.

Detection Of Solid Pigment In Dermatoscopy Images Using Texture Analysis, Murali Anantha, William V. Stoecker, Randy Hays Moss

Chemistry Faculty Research & Creative Works

Background/aims: Epiluminescence microscopy (ELM), also known as dermoscopy or dermatoscopy, is a non-invasive, in vivo technique, that permits visualization of features of pigmented melanocytic neoplasms that are not discernable by examination with the naked eye. ELM offers a completely new range of visual features. One such feature is the solid pigment, also called the blotchy pigment or dark structureless area. Our goal was to automatically detect this feature and determine whether its presence is useful in distinguishing benign from malignant pigmented lesions.

Methods: Here, a texture-based algorithm is developed for the detection of solid pigment. The factors d and a …

Nonlinear Parameter Estimation Of Excitation Systems, Rajeev Bhaskar, Mariesa Crow, Eric Ludwig, Kelvin T. Erickson, Kirit S. Shah

Electrical and Computer Engineering Faculty Research & Creative Works

This paper details the nonlinear parameter estimation process of an IEEE AC1A type exciter using time-domain system identification techniques. This paper discusses nonlinear parameter estimation techniques, systematic and random noise mitigation strategies, and system validation. This study establishes a strong basis for excitation system parameter estimation.

High Strain Rate Superplasticity In Microcrystalline And Nanocrystalline Materials, S. X. Mcfadden, A. V. Sergueeva, Rajiv S. Mishra, A. K. Mukherjee

Materials Science and Engineering Faculty Research & Creative Works

Superplasticity has evolved to become a significant industrial forming process. The phenomenon of superplasticity is explored at high strain rates where it is economically more attractive. True tensile superplasticity has been demonstrated in nanocrystalline materials. The difference in the details of superplasticity between the nanocrystalline and microcrystalline state is emphasised.

Rhizosphere Competitiveness Of Trichloroethylene-Degrading, Poplar-Colonizing Recombinant Bacteria, Hojae Shim, Sadhana Chauhan, Doohyun Ryoo, Kally Bowers, Stuart M. Thomas, Keith A. Canada, Thomas K. Wood, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Indigenous bacteria from poplar tree (Populus canadensis var. eugenei `Imperial Carolina') and southern California shrub rhizospheres, as well as two tree-colonizing Rhizobium strains (ATCC 10320 and ATCC 35645), were engineered to express constitutively and stably toluene o-monooxygenase (TOM) from Burkholderia cepacia G4 by integrating the tom locus into the chromosome. The poplar and Rhizobium recombinant bacteria degraded trichloroethylene at a rate of 0.8 to 2.1 nmol/min/mg of protein and were competitive against the unengineered hosts in wheat and barley rhizospheres for 1 month (colonization occurred at a level of 1.0 × 10⁵ to 23 × 10^{5 …}

Experimental Investigation Of Cold-Formed Steel Beam-Column Sub-Frames: Pilot Study, M. F. Wong, K. F. Chung

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

This paper presents the findings of an experimental investigation on the structural performance of bolted moment connections in cold-formed steel beam-column sub-frames. A total of eight tests with three different connection configurations in both internal and external columns were carried out. Double lipped C-sections back-to-back with hot rolled steel gusset plates of 10 mm and of 16 mm in two different shapes were tested; four bolts per member were used in the connections. Among the tests, three different modes of failure were identified and the measured moment resistances at the connections were found to vary from 36% to 97% of …

Fire Resistance Of Loadbearing Lsf Assemblies, Farid Alfawakhiri, Mohamed A. Sultan

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

This paper presents an analytical thermal-structural model for loadbearing lightweight steel framed (LSF) walls exposed to fire on one side. The model reflects temperature and deformation data from six standard fire resistance tests conducted recently by the National Research Council of Canada in partnership with the North American steel industry. Some characteristic patterns in thermal transmission and structural behaviour are discussed. Temperature histories across LSF assemblies are simulated numerically by explicit integration of transient heat transfer equations. The apparent thermal properties are calibrated for gypsum board and three types of insulation. Analytical procedures are presented to simulate lateral deformation histories …

A General Design Rule For Bearing Failure Of Bolted Connections Between Cold-Formed Steel Strips, K. F. Chung, K. H. Ip

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

This paper presents the results of a finite element investigation on the structural performance of cold-formed steel bolted connections. A parametric study on various connection configurations was performed to relate the bearing resistances of cold-formed steel bolted connections with steel strengths and thicknesses, and bolt diameters. A semi-empirical design rule for bearing resistances of bolted connections based on finite element results is proposed in which the bearing resistances are directly related with the design yield strength, and the design tensile strength of steel strips, steel thickness, and also with bolt diameters. Design expressions for resistance contributions due to both bearing …

Evaluation Of Cold-Formed Steel Connections Attached With Pneumatically Driven Pins, Wimal Suaris, Stuart Werner Baur

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

A comprehensive experimental study was conducted to examine the shear and tensile strength of pneumatically driven pin connections used in cold-formed steel construction. This study included the key parameters that influence the connection strength: steel thickness (16-, 18- and 20-gauge steel), sheathing thickness (1/2" Unipan and 1/2" Dens-Glass Gold). The shear design values given in the AlSI design specifications for screw connections are compared with those obtained from a series of lap shear tests and a good agreement is obtained. Initial analysis of the AlSI design equation for tensile failure due to pull-over yielded poor results when compared to the …

Lessons From Recent Collapses Of Metal Buildings, David B. Peraza

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

This paper presents case studies of three roof collapses of metal buildings, discusses the most signigicant features of each case, and summarizes lessons learned that can be used to reduce future failures.

Estimation Of Restraint Forces For Z-Purlin Roofs Under Gravity Loads, M. C. Neubert, Thomas M. Murray

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

The current specification provisions for the prediction of lateral restraint forces in Z-purlin supported roof systems under gravity loads are in Section D3.1 of the 1996 AlSI Specification for the Design of Cold-Formed Steel Structural Members (1996). The provisions need refinement, because they are empirical, have an incorrect treatment of roof slope and system effects, and ignore the effect of panel stiffness on restraint forces. Therefore, a new restraint force design procedure, having a stronger reliance on engineering principles, is proposed. Elastic stiffness models, with varying roof slope, panel stiffness, and cross-sectional properties, were used to develop the procedure. A …

Compression Tests On Cold-Formed Angles Loaded Parallel With A Leg, Dan Popovic, Kim J. R. Rasmussen, Gregory J. Hancock

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

This paper describes a series of compression tests on cold-formed equal angles with slender cross-section. The angles were tested between pinned ends and loaded axially with eccentric load which caused bending parallel with a leg. The test data are compared with the design rules of the Australian and American specifications for cold-formed and hot-rolled steel structures, as well as the ASCE Standard for the Design of Latticed Steel Transmission Structures. The rules of the specifications for cold-formed steel structures (AS/NZS4600 and AlSI) are shown to be very conservative. The cause of the conservatism is explained and improved design rules are …

On The Structural Behavior Of Composite Beams Using Cold-Formed Shapes, Maximiliano Malite, Walter A. Nimir, Jose Jairo De Sales, Roberto Martins Goncalves

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

Cold-formed shapes have been increasingly employed in the construction of small multiple-floored buildings in Brazil, because wide flange shapes required to meet the demand are unavailable on the Brazilian market. Because existing codes fail to cover the design of composite beams constituted of cold-formed shapes, Brazilian design engineers have usually disregarded the contribution of the slab or have adopted improvised calculations that may to lead to unsafe results. The structural behavior of composite beams, constituted of cold-formed double channel shapes and connected to the concrete slab by means of shear connectors that were also cold-formed, was investigated experimentally. Simply supported …

Flexural Wrinkling Behaviour Of Lightly Profiled Sandwich Panels, Mahen Mahendran, D. Mcandrew

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

In Australia, sandwich panels are commonly made of flat or lightly profiled steel faces and expanded polystyrene foam cores. Flexural wrinkling is often the governing criterion in the design of these panels. The use of lightly profiled faces is expected to increase the flexural wrinkling stress considerably whereas the presence of joints between the polystyrene foam slabs in the transverse direction introduces a reduction to the flexural wrinkling stress. Therefore a series of full scale experiments and finite element analyses were conducted to evaluate the effects of lightly profiled faces and transverse joints on the flexural wrinkling stress of panels …

Stub Column Tests On Cold-Formed Steel Angle Sections, M. Dhanalakshmi, N. E. Shanmugam

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

An investigation on the ultimate load capacity of non-perforated and perforated equal angle cold-formed steel stub columns is presented in this paper. An experimental study has been undertaken to study the behavior of such members subjected to compression. Members were tested to failure under axial or eccentric loading. A comparison of experimental and finite element failure loads, as well as the failure modes of tested specimens, shows that the finite element model is capable of predicting the ultimate load capacity and the failure modes with reasonable accuracy.

Lateral Buckling Of Prismatic Members About An Imposed Axis Of Rotation, Leopold K. Sokol

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

This paper deals with the lateral buckling of prismatic members whose position of the axis of rotation is imposed by the conditions of lateral support. As a function of the type of connection with the lateral support, the rotation may be free or hindered (elastic end restraint). This may concern, for instance, the case of a purlin stabilized by a roof structure or of a column stabilized by an external cladding or by another type of efficient continuous bracing. Usually, the check of this type of instability is complex and leads to sophisticated and tedious computations. In order to avoid …

Experimental Investigation Of Cold-Formed Channels Subjected To Combined Bending And Web Crippling, Ben Young, Gregory J. Hancock

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

An experimental investigation of cold-formed channels subjected to combined bending and web crippling is described in this paper. A series of tests was performed on unlipped channels rolled from high strength structural steel sheets having nominal plate thickness up to 6 mm, and a maximum web slenderness value of 45. This value is considerably lower than the intended web slenderness values used in the Australian/New Zealand Standard (AS/NZS 4600, 1996) and the American Iron and Steel Institute (AISI, 1996) Specification for cold-formed steel structures. In the past, the typical thickness of cold-formed steel members was less than 3 mm, and …

Web Crippling Of Cold Formed Steel C-And Z- Sections, B. Beshara, R. M. Schuster

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

An experimental investigation of cold formed steel stiffened C-and Z sections subjected to web crippling is presented in this paper. This study was devoted to two loading conditions according to the AISI Specification, namely End Two Flange (ETF) and Interior Two Flange (ITF) loading, with particular emphasis on large inside bend radius to thickness ratios, R, (up to 12) and the specimens being fastened to the support during testing. There is no experimental data available in the literature regarding the web crippling resistance of such members that are fastened to the support and have inside bend radius to thickness ratios …

Strength Of Bearing Stiffeners In Cold Formed C-Sections, R. M. Schuster, S. R. Fox

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

The applications of cold formed steel in residential construction have been increasing rapidly in recent years around the world. Some framing practices have been developed that are not covered by the current design specifications, such as using thin cold formed steel stud sections as web stiffeners for C-section floor joists. Earlier tests have shown that the current design methods are unconservative when applied to the types of stiffeners in common usage today. There are a number of variables that influence the capacity of these stiffeners such as stiffener type, position on the joist and connections. All parameters need to be …

Fe Models For Sheeting Under Interaction Load, Jan Kerstens, Bert Snijder, Monique Bakker, H. Hofmeyer

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

Experiments show that, after ultimate load, sheeting may fail by three distinct post-failure modes. In this paper, three finite element models are presented, one for each post-failure mode. One of the finite element models was difficult to develop. A spring model explains this. The finite element models show that, at ultimate load, only two different ultimate failure modes exist. This is important for the development of mechanical models for sheeting failure.

A Design Approach For Complex Stiffeners, Andrew T. Sarawit, Teoman Pekoz

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

This paper presents a design approach for laterally braced cold-formed steel flexural members with edge stiffened flanges other then simple lips. The design method for flexural members given by Schafer and Pekoz (1999) is used here for designing these complex stiffeners. The method integrates distortional buckling into the unified effective width approach currently used in most cold-formed steel design specifications. A finite element method was first used to investigate the post-buckling behavior and carry out initial geometric imperfection sensitivity studies for various types of stiffeners. Then parametric studies were carried out for different types of stiffeners to compare the moment …

Cyclic Pull-Out Strength Of Steel Roof And Wall Cladding Systems, Mahen Mahendran, Dhammika Mahaarachchi

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

When crest-fixed thin steel roof cladding systems are subjected to wind uplift, local pull-through or pull-out failures occur prematurely at their screwed connections. During high wind events such as storms and cyclones these localised failures then lead to severe damage to buildings and their contents. In recent times, the use of thin steel battens/purlins has increased considerably. This has made the pull-out failures more critical in the design of steel cladding systems. Recent research has developed a design formula for the static pull-out strength of steel cladding systems. However, the effects of fluctuating wind uplift loading that occurs during high …

Knee Joints In Cold-Formed Channel Portal Frames, Julie Mills

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

Light gauge cold-formed channel sections are frequently used in portal frame construction for small span agricultural and industrial sheds. A testing program at the University of South Australia has shown that the knee joint currently used in these sheds fails at bending moments well below required design values. An alternative joint construction using multiple Teks screws is being developed and is exhibiting much better performance.

Pull-Through Failures Of Crest-Fixed Steel Claddings Initiated By Transverse Splitting, Dhammika Mahaarachchi, Mahen Mahendran

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

Crest-fixed steel claddings made of thin, high strength steel often suffer from local pull-through failures at their screw connections during high wind events such as storms and hurricanes. Currently there aren't any adequate design provisions for these cladding systems except for the expensive testing provisions. Since the local pull-through failures in the less ductile steel claddings are initiated by transverse splitting at the fastener hole, analytical studies have not been able to determine the pull-through failure loads. Analytical studies could be used if a reliable splitting criterion is available. Therefore a series of two-span cladding tests was conducted on a …