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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

An experimental investigation of the mixing of supersonic turbulent streams of non-similar fluids

Forde, J M January 1963 (has links)
No description available.
2

An experimental investigation of turbulent flow characteristics beneath a simulated ice jam

Pahlavan, Hoda 14 September 2016 (has links)
Ice jams have caused serious hazards such as floods in northern countries. Despite several studies focused on river ice jams, a lack of research has been identified in the existing literature to analyze impacts of an ice jam on turbulent flow characteristics. Thus, this research attempts to address this knowledge gap. A better comprehension of flow features beneath an ice jam will help river ice engineers to reduce economic, environmental, and ecological damages. Technical difficulties and safety concerns limit data collection in ice jam field studies. Therefore, a physical model of a river ice jam was constructed in the Hydraulics Research & Testing Facility at the University of Manitoba. Two scenarios were proposed to simulate an ice jam. The first scenario was to use a basic model with constant upstream and downstream water depth. The second scenario was developed as an extension of the first scenario, with a modified setup to allow the upstream water depth to be greater than the downstream water depth. This was done to increase similarity with the real ice jam in nature and improve the results. For the second scenario, different roughness ratios of channel bed to ice jam were defined. Experiments were conducted to quantify the turbulent flow characteristics including streamwise velocity and streamwise turbulence intensity distribution beneath the ice jam. The flow velocities were measured at different locations beneath the ice jam using an acoustic Doppler velocimeter. The turbulence intensities and bed shear stresses were calculated using the measured velocities. The results indicated that the flow velocity and turbulence intensity were a function of the streamwise location beneath the ice jam as well as the roughness of the bed and ice jam. Significant changes were observed in the velocity and turbulence intensity profiles where the boundaries were fully rough, which could influence an ice jam formation, sediment concentration and water quality, as well as river bed deformation. It is believed that the results from this research will improve our fundamental understanding of flow beneath an ice jam, and can be used for validation of subsequent ice jam numerical models. / October 2016
3

Effects of Solcoseryl on Flap Survival

OKA, TOHRU, KANEDA, TOSHIO, TORII, SHUHEI, AKITA, SUSUMU, UEDA, MINORU 11 1900 (has links)
No description available.
4

Experimental Study on the Orbital Motion Induced by Internal Solitary Wave

Wang, Wei-Hung 04 July 2008 (has links)
Many oceanographers have conducted field experiments on internal waves in the South China Sea using SAR imagery, ADCP and CTD. The results arising from these field studies are mostly in terms of wave amplitudes and flow velocities. Despite schematic diagram depicting the orbits of water particle motion has been accepted for more than decades, evidence has not been available from field observations or laboratory experiments. Laboratory experiments on water-particle motion were conducted on the propagation of elevation and depression ISW in a stratified two-layer fresh/brine fluid system in a steel-framed wave tank of 12 m long with cross section of 0.7 m high by 0.5 m wide. Numerical modeling was also performed using in put data identical to laboratory experiments. Based on our results of the numerical and laboratory experiments, the velocity field displays significant vortex while an internal solitary wave (ISW) propagates on a flat bottom. The strong vortex appears in the region of wave crest or trough. The track of fluid particle velocity in the upper layer is asymmetric and is moving in the opposite direction to that in the lower layer. The maximum horizontal velocity occurs at the crest of an elevation ISW and at the trough of a depression ISW. However, no horizontal flow is found on the interface of the still water level, and no vertical velocity at the wave peak. The vertical and horizontal velocities are antecedent with the water depth. For an elevation ISW, the maximum horizontal velocity appears in the lower layer, and vice versa for a depression ISW. The direction of the horizontal velocity in the upper layer is opposite to that in the lower layer. This study presents the results of numerical calculations and laboratory observations of the particles originally resting on a specific level and their movements within an ISW. The finding generated from this research would benefit others on the verification of field results or analytical theory for fluid particle motions associated with ISW.
5

Does Growth Data Make a Difference?: Teacher Decision Making Processes Using Growth Data versus Status Data

Fox, Patricia 10 December 2010 (has links)
This experiment examined decisions made by teachers using only status data with those made by teachers using growth and status data. Middle school math teachers from five schools within a single school division located in Virginia participated in the study. Participants were randomly assigned to either the status only or growth and status group. They were then asked to analyze a sample set of class data and complete a survey in which they rated the success of four types of students, identified teacher strengths and weaknesses, and rated their confidence in and the usefulness of the data received. Teachers with access to growth and status data differed significantly in their ratings of three of the four types of students. Students with high growth/low achievement were rated more favorably by teachers with growth and status data (p < .05). Students with low growth/high achievement and those with low growth/low achievement were rated less favorably by teachers with access to growth and status data (p < .05). Teachers with access to growth and status data also chose different strengths and weaknesses than those with access to only status data. Teachers did not differ significantly in their confidence in the data or the perceived usefulness of the data, although limitations may have influenced this finding.
6

Search and retrieval of source code using the faceted approach

Mendes, Rodrigo Cavalcante 31 January 2008 (has links)
Made available in DSpace on 2014-06-12T15:54:33Z (GMT). No. of bitstreams: 2 arquivo1977_1.pdf: 1819935 bytes, checksum: 4162d549c75996e549bcc53383212659 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Software Reuse has been considered a key concept to increase the quality and productivity of the software development by the reuse of existing artifacts, avoiding build new ones from scratch. However, In order to obtain effective benefits from the software reuse is necessary a set of complementary resources such as: education, active management support and the introduction of appropriate process and tools. In fact, resources that provide mechanism to ease the access of reusable components, such as search and retrieval tools, appear as potential instruments in favor of reuse programs adoption in the organizations. One of the challenges of the search and retrieval tools is how to make that existing components returned have a significant relevance. In this sense, the use of the faceted approach rises as a suitable alternative. This approach proposes the creation of a vocabulary supported by attributes, dividing the components into group of classes based on pre-defined keywords, increasing the level of precision and providing a more flexible classification. Thus, this work presents an extension of search and retrieval tool of reusable components, source code in particular, using the faceted classification approach. In addition, also was developed an auxiliary tool to aid the Domain expert to perform his activities using this approach. Finally, an experimental study evaluates the proposed solution
7

An Interaction Between Anthropomorphism and Personality on Trust in Automated Systems

Haskins, Abraham 22 December 2021 (has links)
No description available.
8

Experimental and Numerical Study of Submerged Inclined Buoyant Jet Discharges into Stagnant Saline Ambient Water

Guo, Yilin 17 December 2020 (has links)
Treated and untreated liquid that is discharged from industrial and desalination plants is one of the main factors that break the ecological balance and destroys aquatic habitat in lakes, rivers and coastal areas where the effluent is discharged. Positively and negatively buoyant jets are two categories of outfalls which are generated because of the destiny difference between the effluent and ambient fluid. In order to ensure minimal impact of the effluent on the environment, it is necessary to estimate the dilution of the jet and compare it with environmental regulations on the level of required dilution to ensure that the concentration of the effluent is diluted quickly enough and the concentration of the effluent at different points does not exceed the allowed concentrations. This study investigated the positively buoyant jet, which happens near the coastal and near water area. For instance, cooling water that flows out from a power plant or factory, wasted water that is discharged from an industrial plant near river, submerged drainage from civil municipal sewer systems and treated water from desalination plant in coastal area. Density difference, velocity and inclined angle of the jet were considered as the main factors that contribute to the jet spreading and were compared to develop the best solution for its dilution. The jet was discharged inclined downward to allow for more mixing and dilution of the effluent with the ambient water. In order to simulate a positive jet, tap water was injected in saline ambient. A large number of experiments were conducted in the laboratory and using camera imaging. The jet trajectory was estimated from the images using image processing and the impact of various parameters such as Froude number and jet velocity were investigated. The opensource software OpenFOAM, was employed for numerical simulations which is a finite volume model ensures mass conservation and allows for flexible mesh size for further accuracy and optimization of computational cost. Using this Computational Fluid Dynamics (CFD) model, the numerical simulations were performed, and the results were compared with laboratory experiments. A Reynold-Averaged Navier-Stokes (RANS) approach was employed in the numerical simulations which offers a good balance between accuracy and computational cost. It was found that the numerical model in conjunction with the second order turbulence model called Launder-Reece- Rodi model (LRR) had a reasonable agreement with the experimental data.
9

Experimental Study of a Liquid Fuel Bluff Body Flame at Elevated Pressures

Paul, Karam 01 January 2021 (has links)
The purpose of this research was to operate a bluff body flame holder with the objective of stabilizing a flame at elevated pressures over a range of equivalence ratios. The ability to have a ground-based test rig capable of maintaining stable flames at high pressures and temperatures is critical in understanding flames present in modern jet engines and gas turbine technologies. The facility was reconfigured multiple times and the resultant flame was imaged within the optical test section. A converging nozzle was utilized to choke the flow and vary the operating pressures up to 5 atm. By regulating mass flow rates of both the fuel and air, the target range of equivalence ratios was achieved. Jet fuel was successfully ignited on the bluff body and a flame was maintained in the recirculation zone. Visualization of flames during the flights of any aircraft is limited due to material and weight requirements, therefore, performing these studies in ground- based facilities is required. Further analysis was performed to characterize C2* and CH* radicals in fuel lean and rich flames.
10

Theoretical and Experimental Studies of Evaporated Thin Film Distributed RC Networks / Evaporated Thin Film Distributed RC Networks

Carson, James 12 1900 (has links)
Thin film uniform and exponential distributed RC networks were fabricated and the network responses were investigated. It was necessary to take dielectric loss into consideration in the theoretical analysis before a close agreement could be obtained between the theoretical and experimental network responses. / Thesis / Master of Engineering (ME)

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