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Cleveland State University

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2007

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Articles 1 - 28 of 28

Full-Text Articles in Engineering

A Computer Model Of Gluconeogenesis And Lipid Metabolism In The Perfused Liver, Elie Chalhoub, Richard W. Hanson, Joanne M. Belovich Dec 2007

A Computer Model Of Gluconeogenesis And Lipid Metabolism In The Perfused Liver, Elie Chalhoub, Richard W. Hanson, Joanne M. Belovich

Chemical & Biomedical Engineering Faculty Publications

A mathematical model of the perfused rat liver was developed to predict intermediate metabolite concentrations and fluxes in response to changes in various substrate concentrations in the perfusion medium. The model simulates gluconeogenesis in the liver perfused separately with lactate and pyruvate and the combination of these substrates with fatty acids (oleate). The model consists of key reactions representing gluconeogenesis, glycolysis, fatty acid metabolism, tricarboxylic acid cycle, oxidative phosphorylation, and ketogenesis. Michaelis-Menten-type kinetic expressions, with control by ATP/ADP, are used for many of the reactions. For key regulated reactions (fructose-1,6-bisphosphatase, phosphofructokinase, pyruvate carboxylase, pyruvate dehydrogenase complex, and pyruvate kinase), rate …


2007 Scholars And Artists Bibliography, Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library, Joanne E. Goodell Ph.D. Nov 2007

2007 Scholars And Artists Bibliography, Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library, Joanne E. Goodell Ph.D.

Scholars and Artists Bibliographies

This bibliography was created for the annual Friends of the Michael Schwartz Library Scholars and Artists Reception, recognizing scholarly and creative achievements of Cleveland State University faculty, staff and emeriti. Dr. Joanne Goodell was the guest speaker.


The Effect Of Tibiofemoral Loading On Proximal Tibiofibular Joint Motion, Jacob Scott, Ho Lee, Wael Barsoum, Antonie J. Van Den Bogert Nov 2007

The Effect Of Tibiofemoral Loading On Proximal Tibiofibular Joint Motion, Jacob Scott, Ho Lee, Wael Barsoum, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The human proximal tibiofibular joint (PTFJ) and its relationship to overall knee joint mechanics have been largely unexplored. This study describes force/displacement data from experiments done on four human cadaveric knee specimens and general conclusions obtained with the help of a statistical modeling technique. Specimens were rigidly affixed at the tibia to a force plate and the femur was attached to a custom made device allowing for manual load application. Motion of the fibular head was tracked relative to the tibial plateau by means of reflective markers and a high speed digital camera synchronized with the force plate data stream. …


On Internal Cone Cracks Induced By Conical Indentation In Brittle Materials, J. Yan, Anette M. Karlsson, X. Chen Nov 2007

On Internal Cone Cracks Induced By Conical Indentation In Brittle Materials, J. Yan, Anette M. Karlsson, X. Chen

Mechanical Engineering Faculty Publications

The conditions for cone cracks to develop due to a conical indentation are investigated. Axisymmetric numerical simulations, based on the finite element method, are conducted, assuming a linear-elastic, perfectly plastic material. A superposition scheme is employed to simulate a range of crack geometries, including various lengths and orientations. The results indicate that the class of cracks investigated is prone to develop internally in brittle materials. Based on a reversed analysis, a new technique is proposed for measuring the fracture toughness in bulk material and thick coatings through one simple indentation test when the cone crack appears.


On The Reference Length And Mode Mixity For A Bimaterial Interface, A. Agrawal, Anette M. Karlsson Oct 2007

On The Reference Length And Mode Mixity For A Bimaterial Interface, A. Agrawal, Anette M. Karlsson

Mechanical Engineering Faculty Publications

We investigate properties that govern interfacial fracture within the framework of linear elastic fracture mechanics, including interfacial fracture toughness, mode mixity,and the associated reference length. The reference length describes the arbitrary location where the mode mixity is evaluated, ahead ofthe crack tip, in a bimaterial system. A method for establishing a reference length that is fixed for a given bimaterial system is proposed. This is referred to as the“characteristic reference length,” with the associated “characteristic mode mixity.” The proposed method is illustrated with an experimental investigation, utilizing a four-point bend test of a bimaterial system.


Bayesian Estimation Via Sequential Monte Carlo Sampling-Constrained Dynamic Systems, Lixin Lang, Wen-Shiang Chen, Bhavik R. Bakshi, Prem K. Goel, Sridhar Ungarala Sep 2007

Bayesian Estimation Via Sequential Monte Carlo Sampling-Constrained Dynamic Systems, Lixin Lang, Wen-Shiang Chen, Bhavik R. Bakshi, Prem K. Goel, Sridhar Ungarala

Chemical & Biomedical Engineering Faculty Publications

Nonlinear and non-Gaussian processes with constraints are commonly encountered in dynamic estimation problems. Methods for solving such problems either ignore the constraints or rely on crude approximations of the model or probability distributions. Such approximations may reduce the accuracy of the estimates since they often fail to capture the variety of probability distributions encountered in constrained linear and nonlinear dynamic systems. This article describes a practical approach that overcomes these shortcomings via a novel extension of sequential Monte Carlo (SMC) sampling or particle filtering. Inequality constraints are imposed by accept/reject steps in the algorithm. The proposed approach provides samples representing …


Multiaxial Thermo-Mechanical Fatigue On Material Systems For Gas Turbines, M. Bartsch, B. Baufeld, M. Henzelmann, Anette M. Karlsson, S. Dalkilic, L. Chernova Sep 2007

Multiaxial Thermo-Mechanical Fatigue On Material Systems For Gas Turbines, M. Bartsch, B. Baufeld, M. Henzelmann, Anette M. Karlsson, S. Dalkilic, L. Chernova

Mechanical Engineering Faculty Publications

Material systems made from nickel based superalloys with protective coatings have been tested in thermo-mechanical fatigue with superposed thermal gradients, which generated multiaxial stress states. The testing conditions were selected for simulating the fatigue loading in the wall of an internally cooled gas turbine blade of an aircraft engine. After thermo-mechanical testing the damage behaviour of the materials has been investigated by means of microscopic methods. The laboratory experiments have been accompanied by numerical simulations. Based on the results of the simulations and observed damage features the test parameters in subsequent laboratory tests have been controlled to facilitate the validation …


Analysis Of Thermal Effects In Infrared And Interference Microscopy: N-Butane-5a And Methanol-Ferrierite Systems, Lars Heinke, Christian Chmelik, Pavel Kortunov, Dhananjai B. Shah, S. Brandani, Douglas M. Ruthven, Jörg Kärger Aug 2007

Analysis Of Thermal Effects In Infrared And Interference Microscopy: N-Butane-5a And Methanol-Ferrierite Systems, Lars Heinke, Christian Chmelik, Pavel Kortunov, Dhananjai B. Shah, S. Brandani, Douglas M. Ruthven, Jörg Kärger

Chemical & Biomedical Engineering Faculty Publications

Recently, infrared and interference microscopy methods have been increasingly applied to measure internal concentration gradients and hence the uptake of different adsorbates in zeolite crystals. In contrast to conventional macroscopic batch uptake techniques, these microscopic/mesoscopic methods measure changes associated with single zeolite crystals. The analysis of data from these measurements to determine micropore diffusivities has been performed on the basis of the assumption that isothermal conditions prevail during both the adsorption and desorption experiments. This assumption is critically examined in this paper for the case of methanol diffusion in ferrierite crystals during adsorption and desorption to vacuum. It is shown …


Anwendung Von Interferenz- Und Ir-Mikroskopie Zur Charakterisierung Und Untersuchung Des Stofftransportes In Nanoporösen Materialien, Lars Heinke, Christian Chmelik, Pavel Kortunov, Sergey Vasenkov, Douglas M. Ruthven, Dhananjai B. Shah, Jörg Kärger Aug 2007

Anwendung Von Interferenz- Und Ir-Mikroskopie Zur Charakterisierung Und Untersuchung Des Stofftransportes In Nanoporösen Materialien, Lars Heinke, Christian Chmelik, Pavel Kortunov, Sergey Vasenkov, Douglas M. Ruthven, Dhananjai B. Shah, Jörg Kärger

Chemical & Biomedical Engineering Faculty Publications

Die Anwendung der Interferenz-Mikroskopie bedeutet einen entscheidenden Durchbruch in der Untersuchung des Stofftransports von Gastmolekülen in nanoporösen Wirtsmaterialien. Diese Technik ermöglicht die Beobachtung der zeitaufgelösten intrakristallinen Konzentrationsprofile, die durch eine Änderung des umgebenden Gasdruckes entstehen. Dieser Ansatz wurde zur Untersuchung von Adsorptions- und Desorptionsprozessen in verschiedenen Zeolithsystemen verwendet. Die Vorteile dieser Technik, vor allem wenn sie mit Infrarotabsorptionsmessungen kombiniert wird, werden an Hand der experimentellen Resultate des Methanol-in-Ferrierit-Systems illustriert.


Mechanical Behavior Of Fuel Cell Membranes Under Humidity Cycles And Effect Of Swelling Anisotropy On The Fatigue Stresses, Ahmet Kusoglu, Anette M. Karlsson, Michael H. Santare, Simon Cleghorn, William B. Johnson Jul 2007

Mechanical Behavior Of Fuel Cell Membranes Under Humidity Cycles And Effect Of Swelling Anisotropy On The Fatigue Stresses, Ahmet Kusoglu, Anette M. Karlsson, Michael H. Santare, Simon Cleghorn, William B. Johnson

Mechanical Engineering Faculty Publications

The mechanical response of proton exchange membranes in a fuel cell assembly is investigated under humidity cycles at a constant temperature (85°C). The behavior of the membrane under hydration–dehydration cycles is simulated by imposing a humidity gradient from the cathode to the anode. Linear elastic, plastic constitutive behavior with isotropic hardening and temperature and humidity dependent material properties are utilized in the simulations for the membrane. The evolution of the stresses and plastic deformation during the humidity cycles are determined using finite element analysis for two clamping methods and various levels of swelling anisotropy. The membrane response strongly depends on …


Love Canal Tragedy, Alicia Saunte Phillips, Yung-Tse Hung, Paul A. Bosela Jul 2007

Love Canal Tragedy, Alicia Saunte Phillips, Yung-Tse Hung, Paul A. Bosela

Civil and Environmental Engineering Faculty Publications

The purpose of this environmental failure case study paper is to provide educational materials for environmental engineering courses dealing with design and operation of landfills for hazardous waste. In 1978, it was discovered that hazardous waste had contaminated homes and schools in the Love Canal area, a former chemical landfill which became a 15 acre neighborhood of the City of Niagara Falls, New York. On August 7, 1978, the United States President Jimmy Carter declared a federal emergency at the Love Canal. The Love Canal became the first man-made disaster to receive such a designation based on a variety of …


Review Of Rotordynamics, Jerzy T. Sawicki Jul 2007

Review Of Rotordynamics, Jerzy T. Sawicki

Mechanical Engineering Faculty Publications

Book Review of Rotordynamics, by Agnieszka (Agnes) Muszynska. CRC Press, Taylor & Francis Group, Boca Raton, FL, 2005, 1128 pp., ISBN: 0-8247-2399-6


Modeling And Performance Evaluation Of Machining Spindle With Active Magnetic Bearings, Jerzy T. Sawicki, Eric H. Maslen, Kenneth R. Bischof Jun 2007

Modeling And Performance Evaluation Of Machining Spindle With Active Magnetic Bearings, Jerzy T. Sawicki, Eric H. Maslen, Kenneth R. Bischof

Mechanical Engineering Faculty Publications

Active magnetic bearings (AMBs) are increasingly employed in the machine tool industry to exploit their advantages over classical bearings such as high speed capability, rotation accuracy, high stiffness, and accurate displacement tracking capability. Furthermore, the possibility of on-line monitoring of the machining process (e.g., cutting force measurement, tool wear) makes AMB spindles very appealing to the High-Speed Machining (HSM) industry. Despite significant progress already reached in HSM technology, there remain numerous open challenges in modeling and control of magnetic bearings as applied to machining spindles. These include optimum control given AMB magnetic saturation levels, management of nonlinear effects, reduction of …


Real-Time On-Line Space Research Laboratory Environment Monitoring With Off-Line Trend And Prediction Analysis, Kenol Jules, Paul P. Lin Jun 2007

Real-Time On-Line Space Research Laboratory Environment Monitoring With Off-Line Trend And Prediction Analysis, Kenol Jules, Paul P. Lin

Mechanical Engineering Faculty Publications

With the International Space Station currently operational, a significant amount of acceleration data is being down-linked, processed and analyzed daily on the ground on a continuous basis for the space station reduced gravity environment characterization, the vehicle design requirements verification and science data collection. To help understand the impact of the unique spacecraft environment on the science data, an artificial intelligence monitoring system was developed, which detects in near real time any change in the reduced gravity environment susceptible to affect the on-going experiments. Using a dynamic graphical display, the monitoring system allows science teams, at any time and any …


Determining Plastic Properties Of A Material With Residual Stress By Using Conical Indentation, J. Yan, Anette M. Karlsson, X. Chen Jun 2007

Determining Plastic Properties Of A Material With Residual Stress By Using Conical Indentation, J. Yan, Anette M. Karlsson, X. Chen

Mechanical Engineering Faculty Publications

Instrumented indentation is a popular method for determining mechanical properties in engineering materials. However, there are several shortcomings and challenges involved with correctly interpreting the test results. We propose here a unified method for evaluating instrumented indentation testing conducted on a material that exhibits both strain hardening under yielding and which is subjected to uniform, equi-biaxial residual stresses. The proposed method is based on extensive finite element simulations that relate the parameter-space spanned by Young’s modulus, yield strength, strain hardening and residual stress, to the response from the indentation test. Based on reverse analysis, the proposed method can be used …


Preserved Enzymatic Activity Of Glucose Oxidase Immobilized On Unmodified Electrodes For Glucose Detection, Gang Wang, Ngee Mei Thai, Siu-Tung Yau Apr 2007

Preserved Enzymatic Activity Of Glucose Oxidase Immobilized On Unmodified Electrodes For Glucose Detection, Gang Wang, Ngee Mei Thai, Siu-Tung Yau

Electrical and Computer Engineering Faculty Publications

Glucose sensing electrodes have been realized by immobilizing glucose oxidase (GOx) on unmodified edge plane of highly oriented pyrolytic graphite (epHOPG) and the native oxide of heavily doped silicon (SiO2/Si). Both kinds of electrode show direct interfacial electron transfer due to the redox process of the immobilized GOx. The measured formal potential of the redox process agrees with that of the native enzyme, suggesting that the immobilized GOx has retained its enzymatic activity. The electron transfer rates of the GOx immobilized electrode are 2s−1 for GOx/epHOPG electrode and 7.9s−1 for GOx/SiO2/Si electrode, which …


Maximizing Communication Concurrency Via Link-Layer Packet Salvaging In Mobile Ad Hoc Networks, Chansu Yu, Kang G. Shin, Lubo Song Apr 2007

Maximizing Communication Concurrency Via Link-Layer Packet Salvaging In Mobile Ad Hoc Networks, Chansu Yu, Kang G. Shin, Lubo Song

Electrical and Computer Engineering Faculty Publications

Carrier-sense medium access control (MAC) protocols such as the IEEE 802.11 distributed coordination function (DCF) avoid collisions by holding up pending packet transmission requests when a carrier signal is observed above a certain threshold. However, this often results in unnecessarily conservative communication, thus making it difficult to maximize the utilization of the spatial spectral resource. This paper shows that a higher aggregate throughput can be achieved by allowing more concurrent communications and adjusting the communication distance on the fly, which needs provisions for the following two areas. On the one hand, carrier sense-based MAC protocols do not allow aggressive communication …


Determining Equi-Biaxial Residual Stress And Mechanical Properties From The Force-Displacement Curves Of Conical Microindentation, J. Yan, X. Chen, Anette M. Karlsson Apr 2007

Determining Equi-Biaxial Residual Stress And Mechanical Properties From The Force-Displacement Curves Of Conical Microindentation, J. Yan, X. Chen, Anette M. Karlsson

Mechanical Engineering Faculty Publications

An alternative, improved method to determine mechanical properties from indentation testing is presented. This method can determine the elastic modulus, yield strength and equi-biaxial residual stress from one simple test. Furthermore,the technique does not require the knowledge of the contact area during indentation, a parameter that is hard to determine for highly elastic material. The evaluation technique is based on finite element analyses, where explicit formulations are established to correlate the parameter groups governing indentation on stressed specimens.


A Distributed Model Of Carbohydrate Transport And Metabolism In The Liver During Rest And High-Intensity Exercise, E Chalhoub, L. Xie, V. Balasubramanian, Joanne M. Belovich Mar 2007

A Distributed Model Of Carbohydrate Transport And Metabolism In The Liver During Rest And High-Intensity Exercise, E Chalhoub, L. Xie, V. Balasubramanian, Joanne M. Belovich

Chemical & Biomedical Engineering Faculty Publications

A model of reaction and transport in the liver was developed that describes the metabolite concentration and reaction flux dynamics separately within the tissue and blood domains. The blood domain contains equations for convection, axial dispersion, and transport to the surrounding tissue; and the tissue domain consists of reactions representing key carbohydrate metabolic pathways. The model includes the metabolic heterogeneity of the liver by incorporating spatial variation of key enzymatic maximal activities. Simulation results of the overnight fasted, resting state agree closely with experimental values of overall glucose uptake and lactate output by the liver. The incorporation of zonation …


Model-Based Estimation Of Muscle Forces Exerted During Movements, Ahmet Erdemir, Scott Mclean, Walter Herzog, Antonie J. Van Den Bogert Feb 2007

Model-Based Estimation Of Muscle Forces Exerted During Movements, Ahmet Erdemir, Scott Mclean, Walter Herzog, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Estimation of individual muscle forces during human movement can provide insight into neural control and tissue loading and can thus contribute to improved diagnosis and management of both neurological and orthopaedic conditions. Direct measurement of muscle forces is generally not feasible in a clinical setting, and non-invasive methods based on musculoskeletal modeling should therefore be considered. The current state of the art in clinical movement analysis is that resultant joint torques can be reliably estimated from motion data and external forces (inverse dynamic analysis). Static optimization methods to transform joint torques into estimates of individual muscle forces using musculoskeletal models, …


A Microfabricated Segmented-Involute-Foil Regenerator For Enhancing Reliability And Performance Of Stirling Engines: Phase Ii Final Report For The Radioisotope Power Conversion Technology Nra Contract Nas3-03124, Mounir B. Ibrahim, Daniel Danila, Terrence Simon, Susan Mantell, Liyong Sun, David Gedeon, Songgang Qiu, Gary Wood, Kevin Kelly, Jeffrey Mclean Jan 2007

A Microfabricated Segmented-Involute-Foil Regenerator For Enhancing Reliability And Performance Of Stirling Engines: Phase Ii Final Report For The Radioisotope Power Conversion Technology Nra Contract Nas3-03124, Mounir B. Ibrahim, Daniel Danila, Terrence Simon, Susan Mantell, Liyong Sun, David Gedeon, Songgang Qiu, Gary Wood, Kevin Kelly, Jeffrey Mclean

Mechanical Engineering Faculty Publications

An actual-size microfabricated regenerator comprised of a stack of 42 disks, 19 mm diameter and 0.25 mm thick, with layers of microscopic, segmented, involute-shaped flow channels was fabricated and tested. The geometry resembles layers of uniformly-spaced segmented-parallel-plates, except the plates are curved. Each disk was made from electro-plated nickel using the LiGA process. This regenerator had feature sizes close to those required for an actual Stirling engine but the overall regenerator dimensions were sized for the NASA/Sunpower oscillating-flow regenerator test rig. Testing in the oscillating-flow test rig showed the regenerator performed extremely well, significantly better than currently used random-fiber material, …


A Microfabricated Involute-Foil Regenerator For Stirling Engines, Roy C. Tew, Mounir B. Ibrahim, Daniel Danila, Terrence W. Simon, Susan Mantell, Liyong Sun, David Gedeon, Kevin Kelly, Jeffrey Mclean, Gary Wood, Songgang Qiu Jan 2007

A Microfabricated Involute-Foil Regenerator For Stirling Engines, Roy C. Tew, Mounir B. Ibrahim, Daniel Danila, Terrence W. Simon, Susan Mantell, Liyong Sun, David Gedeon, Kevin Kelly, Jeffrey Mclean, Gary Wood, Songgang Qiu

Mechanical Engineering Faculty Publications

A segmented involute-foil regenerator has been designed, microfabricated and tested in an oscillating-flow rig with excellent results. During the Phase I effort, several approximations of parallel-plate regenerator geometry were chosen as potential candidates for a new microfabrication concept. Potential manufacturers and processes were surveyed. The selected concept consisted of stacked segmentedinvolute- foil disks (or annular portions of disks), originally to be microfabricated from stainless-steel via the LiGA (lithography, electroplating, and molding) process and EDM. During Phase II, re-planning of the effort led to test plans based on nickel disks, microfabricated via the LiGA process, only. A stack of nickel segmented-involute-foil …


Noninvasive Quantification Of Fluid Mechanical Energy Losses In The Total Cavopulmonary Connection With Magnetic Resonance Phase Velocity Mapping, Anand K. Venkatachari, Sandra S. Halliburton, Randolph M. Setser, Richard D. White, George P. Chatzimavroudis Jan 2007

Noninvasive Quantification Of Fluid Mechanical Energy Losses In The Total Cavopulmonary Connection With Magnetic Resonance Phase Velocity Mapping, Anand K. Venkatachari, Sandra S. Halliburton, Randolph M. Setser, Richard D. White, George P. Chatzimavroudis

Chemical & Biomedical Engineering Faculty Publications

A major determinant of the success of surgical vascular modifications, such as the total cavopulmonary connection (TCPC), is the energetic efficiency that is assessed by calculating the mechanical energy loss of blood flow through the new connection. Currently, however, to determine the energy loss, invasive pressure measurements are necessary. Therefore, this study evaluated the feasibility of the viscous dissipation (VD) method, which has the potential to provide the energy loss without the need for invasive pressure measurements. Two experimental phantoms, a U-shaped tube and a glass TCPC, were scanned in a magnetic resonance (MR) imaging scanner and the images were …


Modeling Failures Of Thermal Barrier Coatings, Anette M. Karlsson Jan 2007

Modeling Failures Of Thermal Barrier Coatings, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Thermal barrier coatings are commonly used in high temperature parts of gas turbines, to protect the underlying metal substrate from deterioration during high temperature exposure. Unfortunately, the coatings fail prematurely, preventing the design engineers to fully utilize their implementation. Due to the complexity of the coatings, there are many challenges involved with developing failure hypotheses for the failures. This paper reviews some aspects of the current stateof- the-art on modeling failures of thermal barrier coatings, focusing on mechanics based models (such as finite element simulations) where the material physics is incorporated (such as oxidation and diffusion).


Byzantine Fault Tolerant Coordination For Web Services Atomic Transactions, Wenbing Zhao Jan 2007

Byzantine Fault Tolerant Coordination For Web Services Atomic Transactions, Wenbing Zhao

Electrical and Computer Engineering Faculty Publications

In this paper, we present the mechanisms needed for Byzantine fault tolerant coordination of Web services atomic transactions. The mechanisms have been incorporated into an open-source framework implementing the standard Web services atomic transactions specification. The core services of the framework, namely, the activation service, the registration service, the completion service, and the distributed commit service, are replicated and protected with our Byzantine fault tolerance mechanisms. Such a framework can be useful for many transactional Web services that require high degree of security and dependability.


Time-Economic Lifetime Assessment For High Performance Thermal Barrier Coating Systems, Marion Bartsch, Bernd Baufeld, S. Dalkilic, Iulian Mircea, K. Lambrinou, T. Leist, J. Yan, Anette M. Karlsson Jan 2007

Time-Economic Lifetime Assessment For High Performance Thermal Barrier Coating Systems, Marion Bartsch, Bernd Baufeld, S. Dalkilic, Iulian Mircea, K. Lambrinou, T. Leist, J. Yan, Anette M. Karlsson

Mechanical Engineering Faculty Publications

Strategies for time-economic lifetime assessment of thermal barrier coatings (TBC) in service are described and discussed on the basis of experimental results, achieved on material systems with coatings applied by electron beam physical vapour deposition. Service cycles for gas turbine blades have been simulated on specimens in thermo-mechanical fatigue tests, accelerating the fatigue processes by an increase of load frequency. Time dependent changes in the material system were imposed by a separate ageing, where the samples were pre-oxidized prior to the fatigue test. Results of thermo-mechanical fatigue tests on pre-aged and as-coated specimens gave evidence of interaction between fatigue and …


Robust Positively Invariant Cylinders In Constrained Variable Structure Control, Hanz Richter, Brian D. O'Dell, Eduardo A. Misawa Jan 2007

Robust Positively Invariant Cylinders In Constrained Variable Structure Control, Hanz Richter, Brian D. O'Dell, Eduardo A. Misawa

Mechanical Engineering Faculty Publications

This paper proposes the use of cylinders as primary invariant sets to be used in certain state-constrained control designs. Following the idea originally introduced by O'Dell, the primary invariant set is intersected with the state constraints to yield sets which retain the invariance under some conditions. Although several results presented here apply to fairly general nonlinear systems and primary invariant sets of any shape, the focus is on constrained sliding-mode control (SMC) using infinite cylinders as the primary invariant set. Their use is motivated by a coordinate transformation where the sliding motion is decoupled from the overall convergence to the …


Acl Injuries: Do We Know The Mechanisms?, Antonie J. Van Den Bogert, Scott G. Mclean Jan 2007

Acl Injuries: Do We Know The Mechanisms?, Antonie J. Van Den Bogert, Scott G. Mclean

Mechanical Engineering Faculty Publications

Injuries of the anterior cruciate ligament (ACL) remain a frequent occurrence in many sports activities. Recent research has identified risk factors, and prevention strategies are being developed based on these findings. There is, however, still a limited understanding of the actual injury mechanisms. In this presentation we will review the current knowledge on ACL injury mechanisms, and identify needs and opportunities for further research.