Engineering Commons^™

An M/M/1 Retrial Queue With Unreliable Server, Nathan P. Sherman, Jeffrey P. Kharoufeh

Faculty Publications

We analyze an unreliable M/M/1 retrial queue with infinite-capacity orbit and normal queue. Retrial customers do not rejoin the normal queue but repeatedly attempt to access the server at i.i.d. intervals until it is found functioning and idle. We provide stability conditions as well as several stochastic decomposability results.

Developing A Methodology For Assessing Safety Programs Targeting Human Error In Aviation, Scott Shappell, Douglas Wiegmann

Publications

There is a need to develop an effective methodology for generating comprehensive intervention strategies that map current and proposed safety programs onto well-established types of human error. Two separate studies were conducted using recommendations from NTSB accident investigations and several joint FAA and industry working groups. The goal of the studies was to validate a proposed framework for developing and examining safety initiatives that target human error in aviation. The results suggest five approaches to reducing human factors associated with aviation accidents. When combined with the Human Factors Analysis and Classification System, the resulting Human Factors Intervention Matrix will provide …

Systems And Methods For Inspecting Coatings, Kozo Saito, Mohammed I. Hassan Ali, Akira Numasato, Mohammed A. Omar, Sakakibara Masahito, Suzuki Toshikazu, Tanigawa Yasuo

Mechanical Engineering Faculty Patents

A system for detecting defects in paint coatings includes a temperature manipulation apparatus configured to change the temperature of a surface and a coating applied to the surface. The system may further include an infrared sensor for measuring the change in temperature of the surface and coating and a processor to compare the measured change in temperature of the surface and coating to an expected change of temperature in order to determine anomalies in the coatings.

Enzyme–Microbe Synergy During Cellulose Hydrolysis By Clostridium Thermocellum, Yanpin Lu, Yi-Heng P. Zhang, Lee R. Lynd

Dartmouth Scholarship

Specific cellulose hydrolysis rates (g of cellulose/g of cellulase per h) were shown to be substantially higher (2.7- to 4.7-fold) for growing cultures of Clostridium thermocellum as compared with purified cellulase preparations from this organism in controlled experiments involving both batch and continuous cultures. This “enzyme–microbe synergy” requires the presence of metabolically active cellulolytic microbes, is not explained by removal of hydrolysis products from the bulk fermentation broth, and appears due to surface phenomena involving adherent cellulolytic microorganisms. Results support the desirability of biotechnological processes featuring microbial conversion of cellulosic biomass to ethanol (or other products) in the absence of …

Analysis Of Large Scale Image Data Using Out-Of-Core Techniques, Chandrashekara H. Raju, Thomas Wischgoll

Computer Science and Engineering Faculty Publications

No abstract provided.

High Temperature Heat Exchanger Project: Quarterly Progress Report July 1, 2006 Through September 30, 2006, Anthony Hechanova

Publications (NSTD)

Hydrodynamics and thermal numerical modeling coupled with sulfur trioxide decomposition for the one channel geometry with three different channel configurations were performed. The results obtained from the numerical modeling were compared with the baseline design under the same boundary and operation conditions. The case with diamond shaped channels has the highest percentage of sulfuric acid decomposition. The baseline channel geometry has the lowest pressure drop compared with other cases.

Work In Progress: Crossing The Engineering Border Into Art And Society With A Materials Selection For The Life Cycle Course, Katherine C. Chen, Blair London

Materials Engineering

A new course in materials engineering has been developed to incorporate industrial design and sustainability principles. Many current engineering tasks require the ability to comprehend and consider the complicated interplay of technology with the environment and society. Thus the changing skill set required of future engineers is being reflected in the changes with our courses. We are stepping beyond the traditional boundaries of engineering courses to present a more holistic approach to problem solving. The use of materials and processing techniques is applied to product design, and thus involves consideration of the end user and the end of product life. …

Work In Progress: The Five Basic “Positions” Of Engineering, Blair London, Lisa Deyo

Materials Engineering

Classical ballet technique relies on mastery of the five basic positions of the feet. Every movement in classical ballet goes through one or more of these positions. The positions are practiced in class, used in choreography, and become second nature in performance on stage. Engineering may have a similar context. These engineering “positions” are not just the foundational coursework leading up to an engineering degree such as mathematics, chemistry, or physics. Rather, the positions are aspects of engineering that a practicing engineer routinely does to successfully perform as engineers. The engineering positions discussed are: question, analyze, team, write, and speak. …

Scalable Load And Store Processing In Latency Tolerant Processors, Amit Vasant Gandhi

Dissertations and Theses

Memory latency-tolerant architectures support thousands of in-flight instructions without proportionate scaling of cycle-critical processor resources, and thousands of useful instructions can complete in parallel with a long-latency miss to memory. These architectures, however, require large queues to track all loads and stores executed while a long-latency miss is pending. Hierarchical designs alleviate cycle-time impact of these structures but the Content-Addressable-Memory (CAM) and search functions required to enforce memory ordering and provide data-forwarding place high demand on area and power.

Many recent proposals address the complexity of load and store queues. However, none of these proposals addresses the fundamental source of …

Power Electronic Courses That Work, Taufik

Electrical Engineering

This paper presents approaches that have been implemented in power electronic courses to be more appealing to electrical engineering students and hence increase their enrollments. The approaches entail redesigning the structure and content of the courses along with developing new laboratory experiments to better align the lab with the lecture portion of the courses and to reflect recent practical issues in power electronics. In addition to lab experiments, the redesigned courses provide students with an opportunity to apply their knowledge in assigned hardware projects that illustrated many of the points learned in the lecture portion of the course with increasing …

Mechanical Response Of Fuel Cell Membranes Subjected To A Hygro-Thermal Cycle, Ahmet Kusoglu, Anette M. Karlsson, Michael H. Santare, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The mechanical response of fuel cell proton exchange membranes subjected to a single hygro-thermal duty cycle in a fuel cell assembly is investigated through numerical means. To this end, the behavior of the membrane with temperature and humidity dependent material properties is simulated under temperature and humidity loading and unloading conditions. The stress-evolution during a simplified operating cycle is determined using finite element analysis for two clamping methods and two alignments of the bipolar plates. It is shown that compressive, plastic deformation occurs during the hygro-thermal loading, resulting in tensile residual stresses after unloading. These residual in-plane stresses in the …

An Evaluation Of Attributes And Competencies For Manufacturing Engineering Technology Graduates, Loni S. Williamson

Theses and Dissertations

The purpose of this study is to determine the required attributes and competencies required for a graduate from a manufacturing engineering technology baccalaureate program. A document called “Competencies of Manufacturing Engineering Technology Graduates” was compiled in October 2004. This document lists twelve attributes thought to be important for MET graduates: Leadership, Professionalism, Creativity and Problem Solving, Management, Materials, Processes, Quality, Systems, Design, Communication, Safety and Environmental Issues, and Global Awareness. Under each attribute is a list of five to seven competencies creating a total of seventy-three competencies for graduates of an MET baccalaureate program. This list of attributes and competencies …

A Lean Approach To Manage A Capstone Senior Project Course, Manocher Djassemi

Industrial Technology and Packaging

The senior project course (IT461) in the Industrial Technology program at California Polytechnic State University (Cal Poly) is a quarter long capstone course that complements the "learn-by-doing" educational approach at Cal Poly. Our short time frame, an 11-week academic quarter, poses a challenge for both students and faculty. This paper provides details of a new design for the IT461 course. A lean, paperless approach to course management is presented. Using this approach, little or no paper is exchanged between students and faculty. The reduction in waste can be significant in engineering or technology senior project courses. Evaluation of the results …

Bracing Strength And Stiffness Requirements For Axially Loaded Lipped Cee Studs, Perry S. Green, Thomas Sputo, Viswanath Urala

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

No abstract provided.

Shear Rigidity Of Sheathed Walls With Pneumatically Driven Pin Connections, Wimal Suaris, Stuart Werner Baur

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

No abstract provided.

Strength And Stiffness Of Conventional Bridging Systems For Cold-Formed Cee Studs, Perry S. Green, Thomas Sputo, Viswanath Urala

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

No abstract provided.

The 2002 Aisi Cold-Formed Steel Design Manual, Richard C. Kaehler, Helen Chen

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

No abstract provided.

Analysis Of Conventionally Framed Hip Roofs Using Cold-Formed Steel Members, Luke Waldo, Sutton F. Stephens, Roger A. Laboube

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

No abstract provided.

Effects Of Hail Damage On The Carrying Capacity Of Standing Seam Profiles, A. Hubner, H. Saal

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

No abstract provided.

Impact Of Holes On The Elastic Buckling Of Cold-Formed Steel Columns With Application To The Direct Strength Method, Christopher D. Moen, Benjamin W. Schafer

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

No abstract provided.

Mbma-Sponsored Cold-Formed Steel Research 50th Anniversary Retrospective, W. Lee Shoemaker

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

No abstract provided.

Distortional Buckling Of Cold-Formed Steel Members, Maximiliano Malite, Roberto Martins Goncalves, Jorge Munaiar Neto, Gustavo M. B. Chodraui

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

Cold-formed steel members are widely employed in steel construction because their structural components are lighter and more economical than traditional hot-rolled ones. Nowadays, the easy availability and accessible cost of high-strength low-alloy steels, weathering steels and zinc-coated steels have led to members with high width/thickness ratios, rendering them even more susceptible to local buckling, which is characterized by a plate buckling and which can also lead to another buckling mode called distortional buckling, affecting mainly members with edge stiffeners (lipped channels and Z-sections, hat, rack, etc.). Hence, current versions of technical codes for cold-formed steel design have warned about the …

Distortional Buckling Tests On Cold-Formed Steel Beams, Cheng Yu, Benjamin W. Schafer

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

Laterally braced cold-formed steel beams generally fail due to local or distortional buckling. When the compression flange is not restrained by attachment to sheathing or paneling, such as in negative bending of continuous members (joist, purlins, etc.), members are prone to distortional failures. However, distortional buckling remains a largely unaddressed problem in the main body of the North American Specification (NAS 2001). Only a limited amount of experimental data on unrestricted distortional buckling in bending is available, therefore a new series of distortional buckling tests was completed. The test details are selected specifically to insure that distortional buckling is free …

Local-Plate And Distortional Post-Buckling Behavior Of Cold-Formed Steel Lipped Channel Columns With Intermediate Stiffeners, Nuno Silvestre, Dinar Camotim

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

This paper reports the results of an investigation concerning the local-plate and distortional post-buckling behavior of cold-formed steel lipped channel columns with web and flange intermediate stiffeners. They have all been obtained through geometrically non-linear analyses based on a recently developed and implemented Generalized Beam Theory (GBT) formulation that incorporates (i) conventional (shear undeformable), (ii) shear (non-linear warping) and (iii) transverse extension deformation modes. These results, some of which are compared with values yielded by shell finite element analyses performed in the code ABAQUS (mostly for validation purposes), provide the evolution, along a given local-plate or distortional post-buckling equilibrium path, …

Stress Gradient Effect On The Buckling Of Thin Plates, Cheng Yu, Benjamin W. Schafer

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

This paper presents an analytical method to calculate the buckling stress of a rectangular thin plate under nonuniform applied axial stresses. Two cases are considered, buckling of a plate simply supported on all four sides and buckling of a plate simply supported on three sides with one unloaded edge free and the opposite unloaded edge rotationally restrained. These two cases illustrate the influence of stress (moment) gradient on stiffened and unstiffened elements, respectively. The axial stress gradient is equilibrated by shear forces along the supported edges. A Rayleigh-Ritz solution with an assumed deflection function as a combination of a polynomial …

Cold-Formed Steel Frame Shear Wall Applications With Structural Adhesives, Geynaud Serrette, Ioi Lam, Henry Qi, Hugo Hernandez

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

No abstract provided.

A Detailed Examination Of Interactive Buckling In Plain Channel Sections, A. Aziz

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

No abstract provided.

Direct Strength Method For Lipped Channel Columns And Beams Affected By Local-Plate/Distortional Interaction, Nuno Silvestre

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

No abstract provided.

Lateral Distortional Buckling Behaviour Of A New Cold-Formed Hollow Flange Channel Section, Dhammika Mahaarachchi, Mahen Mahendran, Herm Hofmeyer

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

No abstract provided.

Section Moment Capacity Of A New Cold-Formed Hollow Flange Channel Section, Mahen Mahendran, Dhammika Mahaarachchi

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

No abstract provided.