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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Dynamic properties of rapid limb movement as a function of spatial and temporal variables

Gowitzke, Barbara A. January 1900 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Bibliography: leaves 165-171.
12

Drag Coefficients for Magnetically Accelerated Spheres

Liang, Jann-Wuu 01 August 1966 (has links)
The objective of this study was to determine the correlation of the drag coefficient of an accelerating sphere in the liquid medium over a range of Reynolds number from 0.1 to 100, 000. A magnetic accelerator was used to obtain an acceleration for the sphere, the data was recorded using a photograph and a digital computer was used to reduce the data.
13

An Experimental Investigation of the Effect of a Constant Body Force Field Upon the Drag Coefficient of a Sphere

Boyack, Brent Evans 30 May 1964 (has links)
The object of this thesis was to present the method and results of an experimental determination and correlation of the drag coefficients of accelerating spheres.
14

Acceleration constraints in modeling and control of nonholonomic systems

Bajodah, Abdulrahman H. 01 December 2003 (has links)
No description available.
15

Acceleration constraints in modeling and control of nonholonomic systems

Bajodah, Abdulrahman H., January 2003 (has links) (PDF)
Thesis (Ph. D.)--School of Aerospace Engineering, Georgia Institute of Technology, 2004. Directed by Dewey H. Hodges. / Vita. Includes bibliographical references (leaves 162-176).
16

Effect of contact-release angle on hand-handrim for peak velocity

Moon, Jungun January 1992 (has links)
The purpose of this study was to investigate the relationships between the arm joint angle at contact-release with peak velocity in experienced cerebral palsied athletes during wheelchair propulsion. The subjects (n = 5) exercised for a few minutes to familiarize themselves with the roller set up. After practice, each subject was asked to push the wheelchair as fast as possible up to 10 seconds. A tach-generator was attached to the core of the roller and interfaced to a computer via an eight bit A/D converter. The sampling rate of the roller speed was 200Hz. One video camera operating at 30 frames per second, and posisioned 7 m from the roller side was used. The data were analyzed for shoulder, elbow, and wrist angles with the Peak Performance program in I.B.M. compatible computer. Subjects' peak velocities were 8.85, 4.49, 4.19, 3.66, and 4.09 m/s, and the mean percent of contact and release times were 32.8% vs 67.2%. Shoulder, elbow, and wrist contact angles were not statisticaly in this study. Results indicate that contact-release angle on hand-handrim was effected for peak velocity. Also there was no significantrelationship between speed and cycle time.Key WordsRacing wheelchair, cerebral palsy, Peak velocity, Propulsion, Joint angle. / School of Physical Education
17

Design, construction, and testing of an electro-magnetically launched model glider

Zeitlin, Marc Jeffrey January 1981 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1981. / Microfiche copy available in Archives and Barker. / Vita. / Includes bibliographical references. / by Marc Jeffrey Zeitlin. / M.S.
18

Quantitative Assessment of Driver Speeding Behavior Using Instrumented Vehicles

Ogle, Jennifer Harper 18 April 2005 (has links)
Previous research regarding the relationship between speeding behavior and crashes suggests that drivers who engage in frequent and extreme speeding behavior are over-involved in crashes. However, many of these earlier studies relied on estimates of prevailing and pre-crash speeds, and as a result, their conclusions have been questioned. Over the last several years automotive manufacturers have begun installing airbag systems that collect and maintain accurate pre-crash speeds. Though, patterns of driver speeding behavior are also necessary to discern whether drivers who regularly participate in speeding have increased risk of crash involvement. This dissertation presents a framework and methods for quantifying and analyzing individual driver behavior using instrumented vehicles. The goals of the research were threefold: 1) Develop processing methods and observational coding systems for quantifying driver speeding using instrumented vehicle data; 2) Develop a framework for analyzing aggregate and individual driver speeding behavior; and 3) Explore the potential application of behavioral safety concepts to transportation safety problems. Quantitative assessments of driver speeding behavior could be used in combination with event data recorder data to analyze crash risk. Additionally, speed behavior models could aid in the early identification of problem behavior as well as in the development of targeted countermeasure programs. For this research, 172 instrumented vehicles from the Commute Atlanta program were utilized to collect individual driver speeding behavior. Continuous monitoring capabilities allowed the capture of speed and location for every second of vehicle operation. Driver speeds were then matched to road networks and subsequently to posted speed limits using a geographic information system. This allowed differences between the drivers speed and the posted speed. Several processes were developed to assess the accuracy and the completeness of the data prior to analysis. Finally, metrics and analysis frameworks were tested for their potential usefulness in future behavioral risk analysis. The results of the research were both positive and staggering. On average, nearly 40% of all driving activity by the sample population was above the posted speed limit. The amount and extent of speeding was highest for young drivers. Trends indicate that speeding behavior decreases in amount and extent as age increases.
19

Theoretical and experimental development of an active acceleration compensation platform manipulator for transport of delicate objects

Dang, Anh X. H. 12 1900 (has links)
No description available.
20

Aerodynamic design, analysis, and validation of a supersonic inflatable decelerator

Clark, Ian Gauld 06 July 2009 (has links)
Since the 1970's, NASA has relied on the use of rigid aeroshells and supersonic parachutes to enable robotic mission to Mars. These technologies are constrained by size and deployment condition limitations that limit the payload they can deliver to the surface of Mars. One candidate technology envisioned to replace the supersonic parachute is the supersonic inflatable aerodynamic decelerator (IAD). This dissertation presents an overview of work performed in maturing a particular type of IAD, the tension cone. The tension cone concept consists of a flexible shell of revolution that is shaped so as to remain under tension and resist deformation. Systems analyses that evaluated trajectory impacts of a supersonic IAD demonstrated several key advantages including increases in delivered payload capability of over 40%, significant gains in landing site surface elevation, and the ability to accommodate growth in the entry mass of a spacecraft. A series of supersonic wind tunnel tests conducted at the NASA Glenn and Langley Research Centers tested both rigid and flexible tension cone models. Testing of rigid force and moment models and pressure models demonstrated the new design to have favorable performance including drag coefficients between 1.4 and 1.5 and static stability at angles of attack from 0º to 20º. A separate round of tests conducted on flexible tension cone models showed the system to be free of aeroelastic instability. Deployment tests conducted on an inflatable model demonstrated rapid, stable inflation in a supersonic environment. Structural modifications incorporated on the models were seen to reduce inflation pressure requirements by a factor of nearly two. Through this test program, this new tension cone IAD design was shown to be a credible option for a future flight system. Validation of CFD analyses for predicting aerodynamic IAD performance was also completed and the results are presented. Inviscid CFD analyses are seen to provide drag predictions accurate to within 6%. Viscous analyses performed show excellent agreement with measured pressure distributions and flow field characteristics. Comparisons between laminar and turbulent solutions indicate the likelihood of a turbulent boundary layer at high supersonic Mach numbers and large angles of attack.

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