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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.
31

The Lift and Drag Measurements of Single Cylinder with Momentum Injection in Cross Flow

Chuang, Fu-Chi 08 September 2005 (has links)
The fluid forces on a single cylinder in cross flow are measured experimentally by strain gauges. The drag and lift coefficients of the cylinder are measured with momentum injection of various direction and magnitude. The results show that the drag coefficient of the cylinder is reduced with momentum injection. For higher Reynolds numbers, the magnitude of momentum injection must be increased to maintain the effectiveness of momentum injection. The influence of the drag coefficient is reduced when the angle of momentum injection is increased, and then the lift coefficient is varied obviously.
32

Effects of beef enhancement with non-meat ingredients, blade tenderization, and vacuum tumbling on quality attributes of four beef cuts stored in a high oxygen environment

Williams, Tracey Ann 17 February 2005 (has links)
The objective of this study was to evaluate the effects of non-meat ingredients, blade tenderization and vacuum-tumbling on the textural, visual and sensory characteristics of steaks from Biceps femoris, Supraspinatus, Triceps brachii long head, and Longissimus dorsi muscles packaged in high oxygen, modified atomosphere (MAP) system. United Department of Agriculture (USDA) Select muscles (n=72) from each cut were obtained from a commercial processor over three processing days. Muscles were aged for five days at 4ºC. Denuded muscles within a processing day were randomly assigned to one of 24 treatments. This study was a 2 x 4 x 3 factorial arrangement where treatments were control, injection (injected or non-injected), blade tenderization (0, 1, or 2 passes) and vacuum-tumbling (0, 5, 10 or 20 minutes). Injected muscles contained up to 10% of a brine containing 1.55% potassium lactate, 0.1% sodium diacetate, 0.3% sodium tripolyphosphate blend and 0.4% salt in the final product. Muscles were vacuumtumbled and blade tenderized sequentially after injection. Steaks from the muscles were stored in a high oxygen (80% O2, 20% CO2) MAP system for 0, 3, 7, 10 and 14 days at 2ºC. Steaks were evaluated for package purge (%), Warner-Bratzler shear force (kg), cook loss (%), cook time (min), pH, CIE L* a* b* color space values and trained color panel scores on each storage day. A trained descriptive attribute sensory panel evaluated steaks on day 1 only. Warner-Bratzler shear force (P<0.01) and trained sensory panel results (P<0.05) showed that the addition of non-meat ingredients improved tenderness in all four muscles. Sensory detectable connective tissue was lower (P<0.01) in injected steaks for all muscles except in Biceps femoris steaks. Injected steaks had higher pH (P<0.01) measurements than non-injected treatments in all muscles except the Triceps brachii long head. Neither blade tenderization nor vacuum-tumbling had consistent effects in all four muscles. Vacuum-tumbled Biceps femoris steaks had lower bitter flavor aromatics (P<0.05). In conclusion, enhancing beef with non-meat ingredients had the greatest impact on the quality attributes of high connective tissue cuts and Longissimus dorsi steaks.
33

The effects of diamond injector angles on flow structures at various Mach numbers

McLellan, Justin Walter 30 October 2006 (has links)
Numerical simulations of a three dimensional diamond jet interaction flowfield at various diamond injector half angles into a supersonic crossflow were presented in this thesis. The numerical study was performed to improve the understanding of the flame holding potential by extending the numerical database envelop to include different injector half angles and examine the flow at Mach 2 and Mach 5. The configuration of a diamond injector shape was found to reduce the flow separation upstream, and produce an attached shock at the initial freestream interaction and the injection fluid has an increased field penetration as compared to circular injectors. The CFD studies were also aimed at providing additional information on the uses of multiple injectors for flow control. The numerical runs were performed with diamond injectors at half angles of 10° and 20° at a freestream Mach number of 5. The transverse counter-rotating pair of vortices found in the 15° does not form within the 10° and 20° cases at freestream Mach number 5. The 10° case had a barrel shock that became streamlined in the lateral direction. The 20° barrel shock had a very large spanwise expansion and became streamlined in the transverse direction. In both cases the trailing edge of their barrel shocks did not form the flat “V” shape, as found in the baseline case. At Mach 2 the 10° and 15° cases both formed the flat “V” shape at the trailing edge of the barrel shocks, and formed the transverse counter rotating vortex pairs. The 10° multiple injector case successfully showed the interaction shocks forming into a larger planer shock downstream of the injectors. The swept 15° case produced interaction shocks that were too weak to properly form a planar shock downstream. This planar shock has potential for flow control. Depending on the angle of incidence of the injector fluid with the freestream flow and the half angle of the diamond injector, the planar shocks will form further upstream or downstream of the injector.
34

Experimental investigation of in situ upgrading of heavy oil by using a hydrogen donor and catalyst during steam injection

Mohammad, Ahmad A A 10 October 2008 (has links)
Experiments were conducted to investigate the feasibility of in situ upgrading of heavy oil by the use of an orgametallic catalyst and a hydrogen donor (tetralin). The experiments used a vertical injection cell into which a mixture of sand, water, and Jobo oil was thoroughly mixed and packed. Two types of runs were conducted: a run where the tetralin and catalyst were mixed within the mixture before packing into the cell, and the other was conducted by injecting a slug of the tetralin-catalyst solution before commencing with the steam injection. The Jobo oil used had an oil gravity of 12.4° API and a viscosity of 7800 cp at 30°C. The injection cell was placed in a vacuum jacket and set to a reservoir temperature of 50°C. Superheated steam at 273°C was then injected into the injection cell at a rate of 5.5 cc/min (cold water equivalent). The cell outlet pressure was maintained at 500 psig. Produced liquid samples were collected periodically through a series of separators. The produced oil was divided into two halves and several measurements and analyses were carried out on them. These included viscosity, density, elemental analysis and liquid composition. Experimental results indicated that tetralin alone was a worthy additive and increased recovery by 15% compared to that of pure steam. The premixed tetralincatalyst run showed improved recovery to that of pure steam by 20%. Experiments also showed that, when the tetralin-catalyst solution was injected rather than mixed, the results were equivalent to tetralin injection runs. Oil production acceleration was displayed by all the runs with tetralin and tetralin-catalyst but was more pronounced with the availability of catalyst.
35

An investigation of vibration-assisted injection molding for enhanced manufacturing /

Kikuchi, Akihisa. January 2001 (has links)
Thesis (Ph. D.)--Lehigh University, 2001. / Includes vita. Includes bibliographical references (leaves 299-317).
36

A study on profile setting of injection molding /

Chen, Xi. January 2002 (has links)
Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references (leaves 271-290). Also available in electronic version.
37

Injection molding scrap reduction a study in the relationships of plastics processing methods /

Nguyen, Duoc T. January 2004 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2004. / Includes bibliographical references.
38

Experimental and numerical analysis of injection molding with microfeatures

Yu, Liyong, January 2004 (has links)
Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xvi, 202 p.; also includes graphics (some col.). Includes abstract and vita. Advisor: Kurt W. Koelling, Dept. of Chemical Engineering. Includes bibliographical references (p. 196-202).
39

Fiesta++ : a software implemented fault injection tool for transient fault injection

Chaudhari, Ameya Suhas 26 January 2015 (has links)
Computer systems, even when correctly designed, can suffer from temporary errors due to radiation particles striking the circuit or changes in the operating conditions such as the temperature or the voltage. Such transient errors can cause systems to malfunction or even crash. Fault injection is a technique used for simulating the effect of such errors on the system. Fault injection tools inject errors in either the software running on the processors or in the underlying computer hardware to simulate the effect of a fault and observe the system behavior. These tools can be used to determine the different responses of the system to such errors and estimate the probability of occurrence of errors in the computations performed by the system. They can also be used to test the fault tolerance capabilities of the system under test or any proposed technique for providing fault tolerance in circuits or software. As a part of this thesis, I have developed a software implemented fault injection tool, Fiesta++, for evaluating the fault tolerance and fault response of software applications. Software implemented fault injection tools inject faults into the software state of the application as it runs on a processor. Since such fault injection tools are used to conduct experiments on applications executing natively on a processor, the experiments can be carried out at almost the same speed as the application execution and can be run on the same hardware as used by the software application in the field. Fiesta++ offers two modes of operation: whitebox and blackbox. The whitebox mode assumes that users have some degree of knowledge of the structure of the software under test and allows them to specify fault injection targets in terms of the application variables and fault injection time in terms of code locations and events at run time. It can be used for precise fault injection to get reproducible outcomes from the fault injection experiments. The blackbox mode is targeted for the case where the user has very little or no knowledge of the application code structure. In this mode, Fiesta++ provides the user with a view of the active process memory and an array of associated information which a user can use to inject faults. / text
40

Factors affecting injection well performance and fracture growth in waterflooded reservoirs

Hwang, Jongsoo 10 February 2015 (has links)
Waterflooding involves the injection of water to displace oil from oil and gas reservoirs. Well over 80% of oil reservoirs will undergo waterflooding at some point in their life. It is, therefore, important to understand some key aspects of this process that have hitherto not been well studied. This dissertation investigates the following aspects of waterflooding: (i) the filtration of solids and oil-in-water emulsions in fractured and unfractured injection wells, (ii) the generation and filtration of oil-in-water (O/W) emulsion droplets in the near-well region or in the fracture, (iii) the height-growth and containment of injection-induced fractures, and (iv) the stress reorientation induced by water injection when waterflooding reservoirs. These aspects are investigated as separate physical phenomena, but their impacts are integrated using the platform of a comprehensive waterflooding injection well model. The first phenomenon investigated is filtration in frac-packed injectors. During long-term water injection, solid particles in the injection water may deposit in the proppant pack of frac-packed injectors. Researchers have not fully understood whether particles will travel without plugging the frac-packs or deposit in the near-well area under the high-velocity flow conditions in the proppants. Filtration behavior under frac-pack flow conditions is the most important factor that determines overall injector performance. In this dissertation the filtration of injected solids under these conditions was experimentally studied, and the effect of frac-pack filtration on the injector performance was predicted. The flow of dilute oil droplets in a porous medium under near-well conditions was experimentally investigated. When the porous medium has a residual oil saturation, oil droplets can be generated by viscous forces overcoming entrapping capillary forces. The generated oil droplets will subsequently participate in filtration processes along with injected oil droplets. If this occurs in the near-injector area, the injectivity can severely decline and this may require expensive remediation processes. In this study, prediction of O/W emulsion flow was improved by experimental observations of the rates of generation and filtration of oil droplets. In a larger scale problem, a 3-dimensional model of water-injection-induced fracture was developed to predict the fracture height growth. If a fracture breaches the bounding layers, the sweep efficiency can be significantly impaired and it could have severe environmental consequences (such as contamination of shallower aquifers or the seabed). During long-term water injection, fracture growth can only be simulated properly when the filtration near fractures, thermo-elastic stress changes and reservoir fluid flow behavior are all concurrently calculated. Based on this new model, the impact of reservoir stress conditions, mechanical properties, and injection-water quality on fracture growth was studied. On a reservoir-scale, the stress reorientation caused by injection-production activities during waterflooding was investigated. A new finite-volume multi-phase reservoir simulation with poro- and thermo-elasticity was developed. This model was applied to various waterflooding well patterns, such as five-, nine-spot, line-drive and horizontal well pairs, and the critical geomechanical responses by injection-production activities during waterflooding operations were analyzed. The model can be used to predict the direction of induced fractures, design infill well locations and configurations and optimize the reservoir sweep. Through the use of both experimental observations and numerical models this work has elucidated various physical phenomena affecting fracture growth and injection-well performance. The findings in this dissertation provide critical data and models that help us to more confidently specify injection water quality, the design of pumping and water treatment facilities, and the optimization of well planning. The models developed in this work can be used to substantially improve the predictions of injection well performance and improve reservoir oil recovery by waterflooding. / text

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