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Articles 1951 - 1980 of 2082

Full-Text Articles in Engineering

Projection-Based Image Registration In The Presence Of Fixed-Pattern Noise, Ernest Armstrong, Stephen C. Cain, Majeed M. Hayat Dec 2001

Projection-Based Image Registration In The Presence Of Fixed-Pattern Noise, Ernest Armstrong, Stephen C. Cain, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

A computationally efficient method for image registration is investigated that can achieve an improved performance over the traditional two-dimensional (2-D) cross-correlation-based techniques in the presence of both fixed-pattern and temporal noise. The method relies on transforming each image in the sequence of frames into two vector projections formed by accumulating pixel values along the rows and columns of the image. The vector projections corresponding to successive frames are in turn used to estimate the individual horizontal and vertical components of the shift by means of a one-dimensional (1-D) cross-correlation-based estimator. While gradient-based shift estimation techniques are computationally efficient, they often …


Pulmonary Arterial Morphometry From Microfocal X-Ray Computed Tomography, Kelly L. Karau, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher C. Hanger, David L. Roerig, Roger H. Johnson, Christopher A. Dawson Dec 2001

Pulmonary Arterial Morphometry From Microfocal X-Ray Computed Tomography, Kelly L. Karau, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher C. Hanger, David L. Roerig, Roger H. Johnson, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

The objective of this study was to develop an X-ray computed tomographic method for pulmonary arterial morphometry. The lungs were removed from a rat, and the pulmonary arterial tree was filled with perfluorooctyl bromide to enhance X-ray absorbance. At each of four pulmonary arterial pressures (30, 21, 12, and 5.4 mmHg), the lungs were rotated within the cone of the X-ray beam that was projected from a microfocal X-ray source onto an image intensifier, and 360 images were obtained at 1° increments. The three-dimensional image volumes were reconstructed with isotropic resolution with the use of a cone beam reconstruction algorithm. …


Public Perceptions Of The Midwest’S Pavements - Iowa - Phase Iii, David Kuemmel, Richard Robinson, Robert J. Griffin, Ronald C. Sonntag, James K. Giese Sep 2001

Public Perceptions Of The Midwest’S Pavements - Iowa - Phase Iii, David Kuemmel, Richard Robinson, Robert J. Griffin, Ronald C. Sonntag, James K. Giese

Transportation Research Center: Public Perception of Midwest Pavements

There are several objectives to this report. The first objective is to describe the sample with regard to the physical pavement data and three measures of driver satisfaction. In this section, the proportion of respondents who are satisfied with pavements on two-lane, rural, state highways will be examined and the distribution of pavement condition and roughness indices will be presented.

The second objective will be a short description of the highway segments and any differences in satisfaction found between regions and pavement types. This was done in Phase II in each state and a letter sent showing the results in …


Microfocal X-Ray Ct Imaging And Pulmonary Arterial Distensibility In Excised Rat Lungs, Kelly L. Karau, Roger H. Johnson, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher C. Hanger, David L. Roerig, Christopher A. Dawson Sep 2001

Microfocal X-Ray Ct Imaging And Pulmonary Arterial Distensibility In Excised Rat Lungs, Kelly L. Karau, Roger H. Johnson, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher C. Hanger, David L. Roerig, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

The objective of this study was to develop an X-ray computed tomographic method for measuring pulmonary arterial dimensions and locations within the intact rat lung. Lungs were removed from rats and their pulmonary arterial trees were filled with perfluorooctyl bromide to enhance X-ray absorbance. The lungs were rotated within the cone of the X-ray beam projected from a microfocal X-ray source onto an image intensifier, and 360 images were obtained at 1° increments. The three-dimensional image volumes were reconstructed with isotropic resolution using a cone beam reconstruction algorithm. The vessel diameters were obtained by fitting a functional form to the …


Multidirectional Compliance And Constraint For Improved Robotic Deburring. Part 2: Improved Bracing, Joseph M. Schimmels Aug 2001

Multidirectional Compliance And Constraint For Improved Robotic Deburring. Part 2: Improved Bracing, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

This two-part paper presents a method for both improving the positioning capability and increasing the effective stiffness (bracing) of a robotic manipulator through multidirectional compliance and constraint. Improved positioning and improved bracing are attained through the effective use of multiple unilateral kinematic constraints in different directions. The companion paper identified how to specify the compliant characteristics of a manipulator so contact forces lead to deflections that eliminate positional misalignments and result in improved relative positioning through force guidance. In this part, we show that the characteristics beneficial to force guidance are the same characteristics that provide improved bracing when partially …


Learning To Move Amid Uncertainty, Robert A. Scheidt, Jonathan B. Dingwell, Ferdinando A. Mussa-Ivaldi Aug 2001

Learning To Move Amid Uncertainty, Robert A. Scheidt, Jonathan B. Dingwell, Ferdinando A. Mussa-Ivaldi

Biomedical Engineering Faculty Research and Publications

We studied how subjects learned to make movements against unpredictable perturbations. Twelve healthy human subjects made goal-directed reaching movements in the horizontal plane while holding the handle of a two-joint robotic manipulator. The robot generated viscous force fields that perturbed the limb perpendicular to the desired direction of movement. The amplitude (but not the direction) of the viscous field varied randomly from trial to trial. Systems identification techniques were employed to characterize how subjects adapted to these random perturbations. Subject performance was quantified primarily using the peak deviation from a straight-line hand path. Subjects adapted their arm movements to the …


Public Perceptions Of The Midwest’S Pavements - Minnesota - Phase Ii, Marquette University, Department Of Civil, Construction, And Environmental Engineering Jul 2001

Public Perceptions Of The Midwest’S Pavements - Minnesota - Phase Ii, Marquette University, Department Of Civil, Construction, And Environmental Engineering

Transportation Research Center: Public Perception of Midwest Pavements

This report covers Phase II of a three-phase pooled-fund project in Wisconsin, Iowa and Minnesota, to determine the perception/satisfaction levels of the driving public and how they correlate with the states’ physical data bases used to determine priorities for pavement improvements on rural, two-lane highways.

In Phase I, six focus groups were conducted in each state to determine the beliefs and issues about pavements that could be used to draft statewide questionnaires. Focus groups were held during the last half of 1996 in all three states. From the focus groups, a language used by the public to describe and differentiate …


2001 Wisdot Specifications - Construction Note, Marquette University, Transportation Research Center Jun 2001

2001 Wisdot Specifications - Construction Note, Marquette University, Transportation Research Center

Transportation Research Center: Noise & Texture Studies

For the past several years, Marquette University has been conducting a research study for WisDOT on tining patterns to reduce the objectionable tire/pavement whine. During the research study, WisDOT issued Construction Notes to implement the interim results of the research rather than tine the pavement according to Subsection 415.5.9.6.3 of the Standard Specifications.

In the completed study, Marquette University has determined that a skewed, randomly spaced, transversely tined surface results in the lowest levels of pavement whine while retaining the favorable friction characteristics achieved under the current specifications. The overall noise level is not reduced by skewed randomly tined surfaces. …


Quality Control Parameters For Robotic Bridge Painting, Yong Bai, Leonhard E. Bernold Apr 2001

Quality Control Parameters For Robotic Bridge Painting, Yong Bai, Leonhard E. Bernold

Civil and Environmental Engineering Faculty Research and Publications

To protect a steel bridge from corrosion, periodic painting is needed. Bridge painting operations are dangerous and hazardous to human health. A robotic bridge painting system is being developed to replace the human being. One major problem with robotic bridge painting is how to achieve the specified coating quality, which includes two aspects: (1) the coating thickness; and (2) the coating appearance. To ensure quality of the robotic bridge painting, the writers have investigated: (1) the parameters that affect the coating thickness and appearance; (2) the values of the parameters to achieve the required thickness and appearance for the robotic …


An Evaluation Of Age Effects On Driver Comprehension Of Flashing Traffic Signal Indications Using Multivariate Multiple Response Analysis Of Variance Models, Alexander Drakopoulos, Richard W. Lyles Mar 2001

An Evaluation Of Age Effects On Driver Comprehension Of Flashing Traffic Signal Indications Using Multivariate Multiple Response Analysis Of Variance Models, Alexander Drakopoulos, Richard W. Lyles

Civil and Environmental Engineering Faculty Research and Publications

Objective: The objective of this experiment was to identify whether drivers comprehended traffic signals differently when turning left at signalized intersections where traffic signals were in “flashing mode” operation. Method:Multivariate multiple response analysis of variance models were used to analyze the simultaneous effects of displayed color combination, age, and geographical location on signal message interpretation. Data were gathered in a laboratory environment. Results: Left-turn and through-signal color combination had a significant effect on subject comprehension. Comprehension was found to be lowest for displays flashing red only, followed by displays flashing red on the left-turn, and yellow on the through-signal, …


Locating Target At High Speed Using Image Decimation Decomposition Processing, Zikuan Chen, Mohammad Rezaul Karim, Majeed M. Hayat Mar 2001

Locating Target At High Speed Using Image Decimation Decomposition Processing, Zikuan Chen, Mohammad Rezaul Karim, Majeed M. Hayat

Electrical and Computer Engineering Faculty Research and Publications

We develop a decimation-decomposition processing technique that consists of judiciously selecting certain decimation-decomposed components of an image and then performing inter-component processing. For a (kx,ky)-decimation decomposition, there may be up to kxky decimation-decomposed components. The minimal surviving and maximal non-surviving lengths associated with inter-component processing algorithm allows for clutter suppression. By removing detection redundancies, one can locate the target at high speed. A “where-then-what” model is proposed for target tracking and recognition. It locates the target by-image decimation-decomposition processing first and then recognizes the target in question using a suitable image recognition technique.


Semiautomated Skeletonization Of The Pulmonary Arterial Tree In Micro-Ct Images, Christopher C. Hanger, Steven Thomas Haworth, Robert C. Molthen, Christopher A. Dawson Feb 2001

Semiautomated Skeletonization Of The Pulmonary Arterial Tree In Micro-Ct Images, Christopher C. Hanger, Steven Thomas Haworth, Robert C. Molthen, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

We present a simple and robust approach that utilizes planar images at different angular rotations combined with unfiltered back-projection to locate the central axes of the pulmonary arterial tree. Three-dimensional points are selected interactively by the user. The computer calculates a sub- volume unfiltered back-projection orthogonal to the vector connecting the two points and centered on the first point. Because more x-rays are absorbed at the thickest portion of the vessel, in the unfiltered back-projection, the darkest pixel is assumed to be the center of the vessel. The computer replaces this point with the newly computer-calculated point. A second back-projection …


Pulmonary Arterial Remodeling Revealed By Microfocal X-Ray Tomography, Kelly L. Karau, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher A. Dawson Feb 2001

Pulmonary Arterial Remodeling Revealed By Microfocal X-Ray Tomography, Kelly L. Karau, Robert C. Molthen, Anita H. Dhyani, Steven Thomas Haworth, Christopher A. Dawson

Biomedical Engineering Faculty Research and Publications

Animal models and micro-CT imaging are useful for understanding the functional consequences of, and identifying the genes involved in, the remodeling of vascular structures that accompanies pulmonary vascular disease. Using a micro-CT scanner to image contrast-enhanced arteries in excised lungs from fawn hooded rats (a strain genetically susceptible to hypoxia induced pulmonary hypertension), we found that portions of the pulmonary arterial tree downstream from a given diameter were morphometrically indistinguishable. This 'self-consistency' property provided a means for summarizing the pulmonary arterial tree architecture and mechanical properties using a parameter vector obtained from measurements of the contiguous set of vessel segments …


Public Perceptions Of The Midwest’S Pavements - Minnesota - Executive Summary, David Kuemmel, Richard Robinson, Robert J. Griffin, Ronald C. Sonntag, James K. Giese Feb 2001

Public Perceptions Of The Midwest’S Pavements - Minnesota - Executive Summary, David Kuemmel, Richard Robinson, Robert J. Griffin, Ronald C. Sonntag, James K. Giese

Transportation Research Center: Public Perception of Midwest Pavements

This report summarizes Minnesota results of a five year, Pooled Fund study involving the Wisconsin, Iowa, and Minnesota DOTs designed to 1) assess the public's perceptions of the departments’ pavement improvement strategies and 2) to develop customer-based thresholds of satisfaction with pavements on rural two lane highways in each state as related to the Departments’ physical indices, such as pavement ride and condition. The primary objective was to seek systematic customer input to improve the Departments’ pavement improvement policies by 1) determining how drivers perceive the departments’ pavements in terms of comfort and convenience but also in terms of other …


Public Perceptions Of The Midwest's Pavements - Phase I - Focus Group Content Analysis - Iowa, University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory Jan 2001

Public Perceptions Of The Midwest's Pavements - Phase I - Focus Group Content Analysis - Iowa, University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory

Transportation Research Center: Public Perception of Midwest Pavements

This research is being conducted as part of a larger study of the public’s perceptions of state-maintained rural highway pavements in Wisconsin, Minnesota, and Iowa. Later stages of this project will involve interviewing residents of the three states by telephone to gather information about people’s concerns about the pavements in general and specific stretches of highways in particular. Information from this effort is expected to aid the states’ Departments of Transportation refine the standards used to set pavement reconstruction priorities to better meet the needs of residents.


Public Perceptions Of The Midwest's Pavements - Iowa - Executive Summary, Robert J. Griffin, David A. Kuemmel, Richard Robinson, Ronald C. Sonntag, James K. Giese Jan 2001

Public Perceptions Of The Midwest's Pavements - Iowa - Executive Summary, Robert J. Griffin, David A. Kuemmel, Richard Robinson, Ronald C. Sonntag, James K. Giese

Transportation Research Center: Public Perception of Midwest Pavements

This report summarizes Iowa results of a five year, Pooled Fund study involving the Wisconsin, Iowa, and Minnesota DOTs designed to 1) assess the public's perceptions of the departments’ pavement improvement strategies and 2) to develop customer-based thresholds of satisfaction with pavements on rural two lane highways in each state as related to the Departments’ physical indices, such as pavement ride and condition. The primary objective was to seek systematic customer input to improve the Departments’ pavement improvement policies by 1) determining how drivers perceive the departments’ pavements in terms of comfort and convenience but also in terms of other …


Public Perceptions Of The Midwest’S Pavements - Minnesota - Phase I (Focus Group), University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory Jan 2001

Public Perceptions Of The Midwest’S Pavements - Minnesota - Phase I (Focus Group), University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory

Transportation Research Center: Public Perception of Midwest Pavements

This research is being conducted as part of a larger study of the public’s perceptions of state-maintained rural highway pavements in Wisconsin, Minnesota, and Iowa. Later stages of this project will involve interviewing residents of the three states by telephone to gather information about people’s concerns about the pavements in general and specific stretches of highways in particular. Information from this effort is expected to aid the states’ Departments of Transportation refine the standards used to set pavement reconstruction priorities to better meet the needs of residents.


Public Perceptions Of The Midwest’S Pavements - Wisconsin - Executive Summary, David Kuemmel, Richard Robinson, Robert J. Griffin, Ronald C. Sonntag, James K. Giese Jan 2001

Public Perceptions Of The Midwest’S Pavements - Wisconsin - Executive Summary, David Kuemmel, Richard Robinson, Robert J. Griffin, Ronald C. Sonntag, James K. Giese

Transportation Research Center: Public Perception of Midwest Pavements

This report summarizes Wisconsin results of a five year, Pooled Fund study involving the Wisconsin, Iowa, and Minnesota DOTs designed to 1) assess the public's perceptions of the departments’ pavement improvement strategies and 2) to develop customer-based thresholds of satisfaction with pavements on rural two lane highways in each state as related to the Departments’ physical indices, such as pavement ride and condition. The primary objective was to seek systematic customer input to improve the Departments’ pavement improvement policies by 1) determining how drivers perceive the departments’ pavements in terms of comfort and convenience but also in terms of other …


Public Perceptions Of The Midwest’S Pavements - Wisconsin - Phase I (Winter Ride), Marquette University,Department Of Civil, Construction, And Environmental Engineering Jan 2001

Public Perceptions Of The Midwest’S Pavements - Wisconsin - Phase I (Winter Ride), Marquette University,Department Of Civil, Construction, And Environmental Engineering

Transportation Research Center: Public Perception of Midwest Pavements

The Wisconsin Winter Ride Survey was designed to determine the extent to which drivers were tolerant of the rougher ride of pavements on rural two-lane highways in the winter. Survey objectives, as such, were centered around this primary question of winter ride tolerance. A telephone survey was conducted by the Wisconsin Survey Research Laboratory (WSRL), which added questions to its quarterly Wisconsin Opinion Poll for the data collection period of January 15 to March 15, 1997. A similar survey focusing only on the topic of winter driving on rural highways was conducted in Minnesota during the same period. Random digit …


Public Perceptions Of The Midwest’S Pavements - Minnesota - Phase Iii (Targeted Survey Report), University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory Jan 2001

Public Perceptions Of The Midwest’S Pavements - Minnesota - Phase Iii (Targeted Survey Report), University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory

Transportation Research Center: Public Perception of Midwest Pavements

This research is being conducted as part of a larger study of the public’s perceptions of state-maintained rural highway pavements in Wisconsin, Minnesota, and Iowa. Later stages of this project will involve interviewing residents of the three states by telephone to gather information about people’s concerns about the pavements in general and specific stretches of highways in particular. Information from this effort is expected to aid the states’ Departments of Transportation refine the standards used to set pavement reconstruction priorities to better meet the needs of residents.


Public Perceptions Of The Midwest’S Pavements - Wisconsin - Phase I (Focus Group), University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory Jan 2001

Public Perceptions Of The Midwest’S Pavements - Wisconsin - Phase I (Focus Group), University Of Wisconsin - Extension, Wisconsin Survey Research Laboratory

Transportation Research Center: Public Perception of Midwest Pavements

This research is being conducted as part of a larger study of the public's perceptions of state-maintained rural highway pavements in Wisconsin, Minnesota, and Iowa. Later stages of this project will involve interview;ing residents of the three states by telephone to gather information about people's concerns about the pavements in general and specific stretches of highways in particular. Information from this effort is expected to aid the states' Departments of Transportation refine the standards used to set pavement reconstruction priorities to better meet the needs of residents.


Development Of Comprehensive Subgrade Deflection Acceptance Criteria - Phase 3 Report, James Crovetti, Jay Schabelski Jan 2001

Development Of Comprehensive Subgrade Deflection Acceptance Criteria - Phase 3 Report, James Crovetti, Jay Schabelski

Transportation Research Center: Subgrade Deflection Studies

This report has presented the findings of Phase III of research conducted to aid in the development of subgrade deflection acceptance criteria for WisDOT. The reconfigured rolling wheel deflectomter (RWD), portable truck-mounted deflection measurement systems, and automated dynamic cone penetrometer (DCP) were utilized on subgrade construction projects throughout the 2000 construction season. Laboratory analysis of soil properties, including Proctor, CBR and unconfined compression tests, were also conducted.

The research findings have validated the concept of using deflection testing results to identify areas of poor in-place stability within constructed subgrades. It is recommended that pilot implementations of deflection acceptance testing be …


2001 Wisdot Specifications - Marquette Staff Introduction, Marquette University, Transportation Research Center Jan 2001

2001 Wisdot Specifications - Marquette Staff Introduction, Marquette University, Transportation Research Center

Transportation Research Center: Noise & Texture Studies

No abstract provided.


2001 Wisdot Specifications - Texture Of Pcc Pavements, Marquette University, Transportation Research Center Jan 2001

2001 Wisdot Specifications - Texture Of Pcc Pavements, Marquette University, Transportation Research Center

Transportation Research Center: Noise & Texture Studies

No abstract provided.


Breakdown Voltage In Thin Iii-V Avalanche Photodiodes, Mohammad A. Saleh Jan 2001

Breakdown Voltage In Thin Iii-V Avalanche Photodiodes, Mohammad A. Saleh

Electrical and Computer Engineering Faculty Research and Publications

  1. The dead-space multiplication theory of Hayat et al. [Journal of Lightwave Technology 10, 1415 (1992)], in conjunction with the multiplication-width-independent ionization-coefficient model developed by Saleh et al. [IEEE Trans. Electron Devices 47, 625 (2000)], are shown to accurately predict breakdown voltages for thin avalanche photodiodes of GaAs, InP, In0:52Al0:48As, and Al0:2Ga0:8As, over a broad range of device widths. The breakdown voltage is determined from the analytical expression for the impulse-response-function decay rate.


Impact-Ionization And Noise Characteristics Of Thin Iii-V Avalanche Photodiodes, Mohammad A. Saleh, Majeed M. Hayat, Paul P. Sotirelis, Archie L. Holmes, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich Jan 2001

Impact-Ionization And Noise Characteristics Of Thin Iii-V Avalanche Photodiodes, Mohammad A. Saleh, Majeed M. Hayat, Paul P. Sotirelis, Archie L. Holmes, Joe C. Campbell, Bahaa E.A. Saleh, Malvin Carl Teich

Electrical and Computer Engineering Faculty Research and Publications

It is, by now, well known that McIntyre's localized carrier-multiplication theory cannot explain the suppression of excess noise factor observed in avalanche photodiodes (APDs) that make use of thin multiplication regions. We demonstrate that a carrier multiplication model that incorporates the effects of dead space, as developed earlier by Hayat et al. provides excellent agreement with the impact-ionization and noise characteristics of thin InP, In/sub 0.52/Al/sub 0.48/As, GaAs, and Al/sub 0.2/Ga/sub 0.8/As APDs, with multiplication regions of different widths. We outline a general technique that facilitates the calculation of ionization coefficients for carriers that have traveled a distance exceeding the …


Direct Current Electrical Stimulation Increases The Fusion Rate Of Spinal Fusion Cages, Jeffrey M. Toth, Howard Seim, Jeffrey D. Schwardt, Wendy B. Humphrey, Joel A. Wallskog, A. Simon Turner Oct 2000

Direct Current Electrical Stimulation Increases The Fusion Rate Of Spinal Fusion Cages, Jeffrey M. Toth, Howard Seim, Jeffrey D. Schwardt, Wendy B. Humphrey, Joel A. Wallskog, A. Simon Turner

Biomedical Engineering Faculty Research and Publications

Study Design. A randomized experimental evaluation of direct current stimulation in a validated animal model with an experimental control group, using blinded radiographic, biomechanical, histologic, and statistical measures.

Objectives. To evaluate the efficacy of the adjunctive use of direct current stimulation on the fusion rate and speed of healing of titanium interbody fusion cages packed with autograft in a sheep lumbar interbody fusion model.

Summary of Background Data. Titanium lumbar interbody spinal fusion cages have been reported to be 90% effective for single-level lumbar interbody fusion. However, fusion rates are reported to be between 70% and 80% in patients with …


Public Perceptions Of The Midwest’S Pavements - Wisconsin - Phase Iii (Final Report), Marquette University, Department Of Civil, Construction, And Environmental Engineering Sep 2000

Public Perceptions Of The Midwest’S Pavements - Wisconsin - Phase Iii (Final Report), Marquette University, Department Of Civil, Construction, And Environmental Engineering

Transportation Research Center: Public Perception of Midwest Pavements

The stratified sample furnished by WisDOT and the participants recruited by the WSRL provided a sample adequate for purposes of fulfilling the objectives of Phase III. The sample as furnished by the DOT was skewed towards better pavement quality based on PDI. However, the sample based on IRI was skewed toward poorer quality pavements. The team believes this shows a balanced sample, and the differences in pavement quality between the two indices are the result of the IRI boundaries for the categories. The categories in the two indices should be in closer agreement, although they measure different characteristics.

Overall, the …


Excessive Strand End Slip In Prestressed Piles, Michael F. Petrou, Baolin Wan, Walter S. Joiner, Constantin G. Trezos, Kent A. Harries Sep 2000

Excessive Strand End Slip In Prestressed Piles, Michael F. Petrou, Baolin Wan, Walter S. Joiner, Constantin G. Trezos, Kent A. Harries

Civil and Environmental Engineering Faculty Research and Publications

This paper presents the results of a research project that investigated excessive strand end slip observed recently in some prestressed piles. From measurements taken in the field, it is apparent that the problem o excessive initial strand slip is independent of pile shape and size. Strand end slip is evident in piles of different manufacturers in different states in the Southeast. Excessive strand end slip was found in both the top and bottom of the cross section of the piles, although the top portion of the cross section generally exhibited much higher initial slip. Several preventive measures can be adopted …


Persistence Of Motor Adaptation During Constrained, Multi-Joint, Arm Movements, Robert A. Scheidt, David J. Reinkensmeyer, Michael A. Conditt, W. Zev Reymer, Ferdinando A. Mussa-Ivaldi Aug 2000

Persistence Of Motor Adaptation During Constrained, Multi-Joint, Arm Movements, Robert A. Scheidt, David J. Reinkensmeyer, Michael A. Conditt, W. Zev Reymer, Ferdinando A. Mussa-Ivaldi

Biomedical Engineering Faculty Research and Publications

We studied the stability of changes in motor performance associated with adaptation to a novel dynamic environment during goal-directed movements of the dominant arm. Eleven normal, human subjects made targeted reaching movements in the horizontal plane while holding the handle of a two-joint robotic manipulator. This robot was programmed to generate a novel viscous force field that perturbed the limb perpendicular to the desired direction of movement. Following adaptation to this force field, we sought to determine the relative role of kinematic errors and dynamic criteria in promoting recovery from the adapted state. In particular, we compared kinematic and dynamic …