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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.
1

High-Speed Photography Using Television Techniques

Glen, Gregory D. 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / There are many applications for High-speed photography, and most rely on film as the primary medium of data acquisition. One such application of interest to the military services is the study of stores separation from aircraft. This type of testing has traditionally used high-speed film to gather data, however, there are many disadvantages to using film, such as the high cost of raw film, as well as the high processing expense after it has been exposed. In addition, there is no way to review data from film until it has been processed, nor is there any way to preview in real-time other conditions such as lighting which may affect the outcome of a test event. This paper discusses the characteristics of television systems with respect to motion picture systems, the challenges of recording and transmitting pictures, as well as the nature of what the first and eventual desired systems might be.
2

Modeling and validation of crop feeding in a large square baler

Remoué, Tyler 01 November 2007
This study investigated the crop density in a New Holland BB960 (branch of CNH Global N.V.) large square baler as examined by crop trajectory from the precompression room to the bale chamber. This study also examined both the top and bottom plunger pressures and critical factors affecting the final top and bottom bale densities.<p>The crop trajectories (wad of crop) were measured using a high-speed camera from the side of the baler through viewing windows. The viewing windows were divided into four regions for determining the crop displacement, velocity and acceleration. Crop strain was used to evaluate the potential change in density of the crop before being compressed by the plunger. Generally, the vertical crop strain was found to be higher in the top half of the bale compared to the bottom. <p>Average strain values for side measurements were 12.8% for the top and 2.1% for the bottom. Plunger pressures were measured to compare peak pressures between the top and bottom halves of each compressed wad of crop, and to develop pressure profiles based on the plungers position. Results of comparing the mean peak plunger pressures between the top and bottom locations indicated the mean pressures were significantly higher at the top location with the exception of one particular setting. Resulting pressure profile graphs aided in qualitatively describing the compression process for both top and bottom locations.<p>A stepwise regression model was developed to examine the difference in material quantity in the top half of the bale compared to the bottom, based on bale weights. The model indicated that flake setting, stuffer ratio and number of flakes had the greatest effect on maintaining consistent bale density by comparing top to bottom halves of each bale. The R2 (coefficient of determination) value for the developed model was of 59.9%. The R2 was low although could be accounted for due to the limited number of data points in the developed model.
3

Modeling and validation of crop feeding in a large square baler

Remou&#x00E9;, Tyler 01 November 2007 (has links)
This study investigated the crop density in a New Holland BB960 (branch of CNH Global N.V.) large square baler as examined by crop trajectory from the precompression room to the bale chamber. This study also examined both the top and bottom plunger pressures and critical factors affecting the final top and bottom bale densities.<p>The crop trajectories (wad of crop) were measured using a high-speed camera from the side of the baler through viewing windows. The viewing windows were divided into four regions for determining the crop displacement, velocity and acceleration. Crop strain was used to evaluate the potential change in density of the crop before being compressed by the plunger. Generally, the vertical crop strain was found to be higher in the top half of the bale compared to the bottom. <p>Average strain values for side measurements were 12.8% for the top and 2.1% for the bottom. Plunger pressures were measured to compare peak pressures between the top and bottom halves of each compressed wad of crop, and to develop pressure profiles based on the plungers position. Results of comparing the mean peak plunger pressures between the top and bottom locations indicated the mean pressures were significantly higher at the top location with the exception of one particular setting. Resulting pressure profile graphs aided in qualitatively describing the compression process for both top and bottom locations.<p>A stepwise regression model was developed to examine the difference in material quantity in the top half of the bale compared to the bottom, based on bale weights. The model indicated that flake setting, stuffer ratio and number of flakes had the greatest effect on maintaining consistent bale density by comparing top to bottom halves of each bale. The R2 (coefficient of determination) value for the developed model was of 59.9%. The R2 was low although could be accounted for due to the limited number of data points in the developed model.
4

Biomechanics of spore discharge in the Basidiomycota

Stolze-Rybczynski, Jessica L. 12 August 2009 (has links)
No description available.
5

ANALYSIS OF VOCAL FOLD KINEMATICS USING HIGH SPEED VIDEO

Unnikrishnan, Harikrishnan 01 January 2016 (has links)
Vocal folds are the twin in-folding of the mucous membrane stretched horizontally across the larynx. They vibrate modulating the constant air flow initiated from the lungs. The pulsating pressure wave blowing through the glottis is thus the source for voiced speech production. Study of vocal fold dynamics during voicing are critical for the treatment of voice pathologies. Since the vocal folds move at 100 - 350 cycles per second, their visual inspection is currently done by strobosocopy which merges information from multiple cycles to present an apparent motion. High Speed Digital Laryngeal Imaging(HSDLI) with a temporal resolution of up to 10,000 frames per second has been established as better suited for assessing the vocal fold vibratory function through direct recording. But the widespread use of HSDLI is limited due to lack of consensus on the modalities like features to be examined. Development of the image processing techniques which circumvents the need for the tedious and time consuming effort of examining large volumes of recording has room for improvement. Fundamental questions like the required frame rate or resolution for the recordings is still not adequately answered. HSDLI cannot get the absolute physical measurement of the anatomical features and vocal fold displacement. This work addresses these challenges through improved signal processing. A vocal fold edge extraction technique with subpixel accuracy, suited even for hard to record pediatric population is developed first. The algorithm which is equally applicable for pediatric and adult subjects, is implemented to facilitate user inspection and intervention. Objective features describing the fold dynamics, which are extracted from the edge displacement waveform are proposed and analyzed on a diverse dataset of healthy males, females and children. The sampling and quantization noise present in the recordings are analyzed and methods to mitigate them are investigated. A customized Kalman smoothing and spline interpolation on the displacement waveform is found to improve the feature estimation stability. The relationship between frame rate, spatial resolution and vibration for efficient capturing of information is derived. Finally, to address the inability to measure physical measurement, a structured light projection calibrated with respect to the endoscope is prototyped.
6

Quantitative measurement and flow visualization of water cavitation in a converging-diverging nozzle

Schmidt, Aaron James January 1900 (has links)
Master of Science / Department of Mechanical and Nuclear Engineering / B. Terry Beck / Mohammad H. Hosni / Cavitation is the change of a liquid to a two-phase mixture of liquid and vapor, similar to boiling. However, boiling generates a vapor by increasing the liquid temperature while cavitation generates vapor through a decrease in pressure. Both processes are endothermic, removing heat from the surroundings. Both the phase change and heat absorption associated with cavitation provide many engineering applications, including contributing to a new type of refrigeration cycle under development. Cavitation can occur at or below the vapor pressure; conditions that delay cavitation and allow for a metastable liquid are not well understood. A converging-diverging nozzle was designed and fabricated to create a low pressure region at the nozzle throat. The converging section of the nozzle increased the water velocity and decreased the pressure, according to Bernoulli’s principle. A cavitation front was formed slightly past the nozzle throat. The cavitation location suggested that the water was metastable near the nozzle throat. Flow through the system was controlled by changing the nozzle inlet and outlet pressures. The flowrate of water was measured while the outlet pressure was lowered. The flowrate increased as the outlet pressure dropped until cavitation occurred. Once cavitation initiated, the flow became choked and remained constant and independent of the nozzle outlet pressure. High-speed imagery was used to visualize the flow throughout the nozzle and the formation and collapse of cavitation in the nozzle’s diverging section. High-speed video taken from 1,000 to 35,000 frames per second captured the formation of the cavitation front and revealed regions of recirculating flow near the nozzle wall in the diverging section. Particle Image Velocimetry (PIV) was used to measure the velocity vector field throughout the nozzle to characterize flow patterns within the nozzle. PIV showed that the velocity profile in the converging section and throat region were nearly uniform at each axial position in the nozzle. In the diverging section, PIV showed a transient, high-velocity central jet surrounded by large areas of recirculation and eddy formation. The single-phase experimental results, prior to cavitation onset, were supplemented by Computational Fluid Dynamics (CFD) simulations of the velocity distribution using Fluent software.
7

A DESIGN FOR A 10.4 GIGABIT/SECOND SOLID-STATE DATA RECORDER

Wise, Richard J. Jr 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / A need has been identified in the Test and Evaluation (T&E) and tactical aircraft communities for a ruggedized high-speed instrumentation data recorder to complement the ever-increasing number of high frame-rate digital cameras and sensors. High-speed digital camera manufacturers are entering this market in order to provide adequate recording capability for their own cameras. This paper discusses a Solid-State Data Recorder (SSDR) for use in Imaging and High-Speed Sensor Data Aquisition applications. The SSDR is capable of a 10.4 Gb/sec sustained, 16Gb/sec burst, input data rate via a proprietary 32-channel-by-10-bit generic high-speed parallel interface, a massively-parallel 256-bit bus architecture, and unique memory packaging design. A 32-bit PCIbus control/archive and dedicated DCRsi™ interface are also employed, allowing data archiving to standard high-speed interfaces (SCSI, Fiber-Channel, USB, etc.) and DCRsi™-compatible tape recorders.
8

Biomechanics of spore discharge in the Basidiomycota

Stolze-Rybczynski, Jessica L. January 2009 (has links)
Title from second page of PDF document. Includes bibliographical references.
9

Metodika zkoumání rychlých a stochastických mechanických dějů / Methodology of fast and stochastic mechanical process research

Kolomazník, Petr January 2008 (has links)
This diploma thesis deals with the research of fast processes. It delineates technique the process is captured by with following interpretation of the results received. Fast processes are captured using high speed video camera system Olympus i-SPEED 2. The actual object of measuring and examination was an air pistol and its initial velocity.
10

Aplikace vysokorychlostního kamerového systému při testování rotujících pryžových dílů / Application high speed camer during testing rotation rubber parts

Pešek, Jan January 2009 (has links)
This diploma thesis introduces Olympus i-SPEED 2 high speed video camera and its use in the testing of rubber parts. The results gained will be applied to tyre tread development. Two mutually connected high speed cameras were used to record the testing process. Final recordings were put together in order to create panoramic photos.

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