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1
Vongvuthipornchai, Somporn. „Well test analysis for non-Newtonian fluid flow /“. Access abstract and link to full text, 1985. http://0-wwwlib.umi.com.library.utulsa.edu/dissertations/fullcit/8603796.
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Nordstrand, Dennis. „Test-enhanced learning, working memory and fluid intelligence“. Thesis, Umeå universitet, Institutionen för psykologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-122471.
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Under det senaste decenniet har testbaserat lärande väl etablerats som ett effektivt sätt att främja hållbar inlärning. Många sorters material och omständigheter har utforskats i relation till denna metod. Endast nyligen har dock individuella skillnader i relation till testbaserat lärande fått uppmärksamhet som ett forskningsområde. Ett område hittills förhållandevis outforskat är relationen mellan individuella skillnader i kognitiv kapacitet och inlärningsprocessen med återhämtning som inlärningsmetod. Denna studie hade för avsikt att utforska denna relation genom att mäta generell flytande intelligens och arbetsminneskapacitet för ett urval av gymnasieelever (n = 189, M = 16.89 år gamla) som använde testbaserat lärande som inlärningsmetod. Resultaten indikerar att arbetsminne och flytande intelligens båda är relaterade till inlärningsprocessen, men att det förstnämnda är så till en signifikant högre grad än det sistnämnda.During the last decade, test-enhanced learning has been thoroughly cemented as an efficient way to promote durable learning. Many materials and conditions have been explored in relation to this method. Only recently, however, have individual differences in relation to test-enhanced learning received attention as an area of study. An area as of yet relatively unexplored is the relationship between differences in cognitive ability and the process of retrieval as a method of learning. The present study set out to explore this relationship by measuring general fluid intelligence and working memory capacity in a sample of upper secondary level students (n = 189, M = 16.89 years of age) who used a test-enhanced learning method. The results indicate that working memory and fluid intelligence are both related to this learning process, however the former to a significantly higher degree than the latter
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Nyekwe, Ichegbo Maxwell. „Investigation of factors effecting yield stress determinations using the slump test“. Thesis, Cape Peninsula University of Technology, 2008. http://hdl.handle.net/20.500.11838/2160.
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Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2008.Certain non-Newtonian fluids exhibit a yield stress which can be measured with a variety of instruments varying from very sophisticated rotary and tube viscometers to hand-held slump cones and cylinders of various sizes. Accurate yield stress measurement is significant for process design and disposal operations for thickenend tailings. The slump value was first related to the yield stress by Murata (1984). Later, that work was corrected by Christensen (1991) for an error in the mathematical analysis. Slump, based on a circular cylindrical geometry was first investigated by Chandler (1986). These concepts led to the study by Pashias et al., (1996) that formed the basis for the current research. The Flow Process Research Centre (FPRC) at the Cape Peninsula University of Technology developed a slump meter designed to lift the cone or cylinder vertically at controlled lifting speeds. In addition the simple hand-held cylinder which is an adaptation of slump cones which were originally developed by the concrete industry to determine the flowability of fresh concrete was also used. The vane technique was used as a control. Cones and cylinders made of stainless steel and PVC were fitted to the slump meter. The yield stresses of four non-Newtonian fluids at different concentrations were tested in four different configurations at different lift speeds to ascertain whether the measuring position, lift speed, slip, geometry, wall surface material, and stability has an effect on the value of yield stress measured. The effect of different predictive models was also ascertained.The cylinder, lump and cone models relating slump to yield stress was used in the dimensional analysis of the results. The objective of this work was to determine if the slump tests (cone, cylinder and the hand-held cylinder) would generate yield stress values comparable to those found using the vane technique. It was establised that there was no significant effect of lift speed, stability, geometry and wall surface material on the value of yield stress. The effect of measuring position on the value of yield stress calculated gave a difference of 25%. Using dimensional analysis, the lump model (Hallbom, 2005) more accurately predicts the material yield stress when using the hand-held cylinder as well as all the cone results (due to its specific geometry), and cylinder configurations, thus affirming the work of Clayton et al., 2003. It is concluded that, although the materials and concentrations tested induced errors within 40%, the hand-held cylinder shows promise as a reliable, quick and simple way of measuring the yield stress.
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Gilmore, Jordan David. „Computational Fluid Dynamics Analysis of Jet Engine Test Facilities“. Thesis, University of Canterbury. Mechanical Engineering, 2012. http://hdl.handle.net/10092/7238.
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This thesis investigates the application of CFD techniques to the aerodynamic analysis of a U-shaped JETC. Investigations were carried out to determine the flow patterns present at a number of locations within the structure of a full U-shaped JETC. The CFD solutions produced in these investigations used recommendations from the literature in the set-up of the CFD solver, and provided the computational component towards problem-specific validation of the CFD techniques used.
A structured series of CFD-aided investigation and design processes were then performed. These processes were based around a series of analyses that evaluated the influence of a number of cell parameters in terms of cell airflow efficiency and velocity distortion. Four cell components; the inlet and exhaust stack baffle arrangements, the turning-vanes, the rear of the working section and augmenter entrance, and the lower exhaust stack, including the BB, were investigated in individual analyses. Throughout the investigations the value of CFD as a design tool was constantly assessed.
Overall, the findings suggest that aerodynamic optimisation of the baffle arrangements would provide the greatest gains to cell airflow efficiency. As some cells contain as many as three baffle arrangements, the potential increases made to cell airflow capacity are sizable. Through implementing the findings of the baffle arrangement investigations, static pressure loss across the five-row baseline arrangement was reduced by 79%.
For low levels of velocity distortion in the upstream region of the working section, the need to design the inlet stack baffles in the turning-vane arrangement was highlighted. Mid-baffle vane alignment, consistent flow channels, and sufficiently low chord to gap ratios should be incorporated into a turning-vane design to maximise flow uniformity. The need for the baffle and vane components to combine with the geometry of the cell to limit adverse pressure gradients was found as a requirement to minimise inner corner separation, and the downstream threat it creates to a safe testing environment.
CFD proved to be a valuable analysis tool throughout the investigations performed in this thesis. The number of design iterations analysed, and the detail of data that could be extracted, significantly exceeded what could have been achieved through an isolated experimental testing programme.
5
Saleh, Amer Mohamed. „Well test and production prediction of gas condensate reservoirs“. Thesis, Heriot-Watt University, 1992. http://hdl.handle.net/10399/813.
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Schreier, Sebastian. „Development of a sloshing test rig“. Aachen Shaker, 2009. http://d-nb.info/997162120/04.
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Swanson, Erik Evan. „Evaluation of the VPI & SU fluid film bearing test rig“. Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09122009-040419/.
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Freemire, Ben. „High pressure gas filled RF cavity beam test at the Fermilab Mucool test area“. Thesis, Illinois Institute of Technology, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3574935.
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With a new generation of lepton colliders being conceived, muons have been proposed as an alternative particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a smaller energy range than a comparable electron collider. This allows a circular collider to be built. As part of the accelerator, it would also be possible to allow the muons to decay to study neutrinos.
Because the muon is an unstable particle, a muon beam must be cooled and accelerated within a short amount of time. Muons are generated with a huge phase space, so radio frequency cavities placed in strong magnetic fields are required to bunch, focus, and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary.
To successfully operate RF cavities in strong magnetic fields, the cavity can be filled with a high pressure gas in order to mitigate breakdown. The gas has the added benefit of providing cooling for the beam. The electron-ion plasma created in the cavity by the beam absorbs energy and degrades the accelerating electric field of the cavity. As electrons account for the majority of the energy loss in the cavity, their removal in a short time is highly desirable. The addition of an electronegative dopant gas can greatly decrease the lifetime of an electron in the cavity.
Measurements in pure hydrogen of the energy consumption of electrons in the cavity range in 10-18 and 10-16 joules per RF cycle per electron. When hydrogen doped with dry air is used, measurements of the power consumption indicate an energy loss range of 10-20 to 10-18 joules per RF cycle per ion, two orders of magnitude improvement over non-doped measurements. The lifetime of electrons in a mixture of hydrogen gas and dry air has been measured from < 1 ns, up to 200 ns. The results extrapolated to the parameters of a Neutrino Factory and Muon Collider indicate that a high pressure gas filled RF cavity will work in a cooling-channel for either machine.
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Andrinopoulos, Nikolaos. „Development of a test facility for experimental investigation of fluid-structure interaction“. Licentiate thesis, KTH, Energy Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10544.
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Fluid-structure interaction phenomena are strongly related to the loading appearing on many energy converting components introducing limitations for improving their efficiency. The term “fluid-structure interaction” includes many phenomena with the “shock wave – boundary layer interaction” being one of the most important. This interaction is commonly met in turbomachines where the flow can accelerate enough to become compressible and can cause separation of the boundary layer formed on the structural components of the machine. This results to fluctuating loading on the structure which can lead to its failure due to High Cycle Fatigue (HCF).
A vibrating structure in compressible flow can become unstable depending on the sign of the aerodynamic damping that the flow has on the structure. Although the mechanism that causes a structure to become unstable is known, the limits of the stability region are not yet possible to predict with reasonable accuracy. It is therefore necessary to investigate the underlying mechanism of fluid-structure interaction by means of experimental and numerical studies for providing prediction tools regarding the stability change.
The present work aims at developing an experimental facility to be used for investigating fluid-structure interaction. The experimental setup is based on the concept of a simplified aeroelastic test case bringing into focus the area of interaction between an oscillating shock wave and a turbulent boundary layer. This work is based on previous research campaigns using the same generic experimental concept but takes the investigation further to higher and so far unexplored reduced frequencies. The experimental setup has been validated regarding its suitability to meet the research objectives by running vibration tests at an initial stage without the effect of flow.
The results from the experimental validation of the facility have shown that the design objectives are met. Specifically the vibration response of the test object concerning vibration amplitude and vibration mode shape is desirable; the vibration amplitude is in the range of 0.5mm and the mode shape remains below the 2nd throughout the targeted frequency range (0-250Hz). This makes the facility suitable for simplified investigation of fluid-structure interaction, bringing the shock foot region into focus.
Having validated the facility performing vibration tests without flow, tests with flow is the next step to take place. Since the vibration response of the test object has been investigated in detail, tests with flow will reveal the influence of fluidstructure interaction on the dynamic response of the test object. Similarly, the influence of this interaction on the flow side can be assessed by monitoring the flow parameters. As a first step for performing this investigation, the design study and the validation results for the experimental setup are presented in this work.
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Uchimoto, Mari L. „Developing a microRNA body fluid identification test for use in forensic casework“. Thesis, University of Huddersfield, 2014. http://eprints.hud.ac.uk/id/eprint/24470/.
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Body fluid identification (BFID) forms a crucial aspect within forensic investigations. BFID is particularly important where the origin of a DNA profile is also needed e.g. sexual assaults. The aim of this work was to develop a RNA-based BFID for use in forensic casework. The test was developed in three stages: exploring co-isolation and single isolation strategies, screening and selecting RNA markers and different casework conditions e.g. low-level, non-human, degraded and mixed samples. Blood, saliva, skin, semen and vaginal material samples were collected. Samples underwent single or co-isolation (DNA, total RNA or messenger RNA), DNA quantification, cDNA synthesis and qPCR using a number of different candidate markers and reference genes for microRNA (miRNA) and messenger RNA. During the development of the test the following novel findings were observed: utilisation of complex co-isolation methods was not need for co-analysis of RNA and DNA; six highly discriminative miRNA markers were identified for miRNA analysis: blood (miR-451 and miR-194); saliva (miR-205); vaginal material (miR-224 and miR-335) and semen (miR-891a). In terms of casework applications, microRNA analysis showed potential for greater sensitivity than current enzymatic methods with the use of appropriate reference gene; species specificity was observed for reference gene RNU44; sample stability was observed in 1-yr bloodstains with miR-451 and RNU44 and successful resolution of major and minor components was achieved.
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Samuel, Madan. „Quantitative assessment of the tympanic membrane displacement test in children and adolescents with shunted hydrocephalus : reproducibility of tympanic membrane displacement test measurements in children with shunted hydrocephalus“. Thesis, University of Southampton, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266378.
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Parks, Benjamin T. „Using the FLUENT computational fluid dynamics code to model the NACOK corrosion test“. Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/38249.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2004.Includes bibliographical references (p. 89-90).
As a part of advancing nuclear technology, computational fluid dynamics (CFD) analysis offers safer and lower-cost results relative to experimental work. Its use as a safety analysis tool is gaining much broader acceptance due to increasing experimental verification. FLUENT is a Computational Fluid Dynamics (CFD) code that offers extensive benchmarks and validations, and is widely accepted by the nuclear engineering community. The Modular Pebble Bed Reactor (MPBR) is among the advanced reactor designs proposed for future deployment. As such, it offers an excellent opportunity to illustrate the possible contributions of computational modeling to the reactor design process. Because the MPBR contains graphite structures and fuel elements, there is significant concern about graphite heating and chemical reactions during an air ingress accident. Some MPBR-relevant experimental safety assurances have been benchmarked using FLUENT. Currently, there is a planned experiment involving natural convection flow and graphite corrosion at the Forschungzentrum Julich in Julich, Germany. Thus far, only a preliminary test of this experiment has been performed. This test has been called the NACOK Corrosion Test, and this thesis presents a model of the test configuration.
(cont.) A methodology is developed by which an efficient analysis of the flow, heat transfer, and corrosion effects of the test are modeled using the FLUENT software. An adequate grid resolution is determined that allows computationally efficient analysis. Steady-state and transient flow and heat transfer effects are modeled, and separate models contain steady-state and transient chemistry effects. The steady-state flow and heat transfer model was used for the grid refinement study; it was determined that a fully-structured, 4,508 element grid was sufficient for analysis of this experiment. The transient flow and heat transfer model confirmed the results of the steady-state analysis in that the transient model had results similar to those of the steady-state model. An effort was made to couple a density-driven pressure drop correlation to this model; however, because of the requirement of a general pressure-drop specification for the entire model, and the temperature dependence of the correlation, an over-specification resulted that caused the solution to diverge. Because the ambient air that causes the buoyancy-induced pressure drop is not modeled, it was determined that specifying a general pressure drop for the entire model was a sufficient and relevant assumption.
(cont.) The steady-state chemistry model was used to perform sensitivity studies by varying the flow rate, graphite temperature, and stoicheometry. Increasing the flow rate results in quicker graphite consumption, although the oxygen exits the system less depleted. Increasing the graphite temperature seems to have little effect on the chemistry effects of the modeL Varying the stoicheometry indicated that more heat is released by CO2 production. Overall, it was determined that most of the graphite chemistry occurs in the reflector region of the model. A transient chemistry model was also created, but because mass transport effects were not modeled, the solution tended to steady-state operation, rather than eventual graphite cooling, which would be the expected result of this test in the laboratory setting.
by Benjamin T. Parks.
S.M.
13
Adham, Tarek Abbas. „The development of test procedure to determine the potential durability of concrete structures“. Thesis, Coventry University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342255.
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Russell, Heather Elizabeth. „Development of a computerised test of fluid ability for children : validating the SWAPS format /“. Title page, table of contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09HS/09hsr9611.pdf.
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Burns, Robert. „Developing a test of premorbib fluid abilities for people from non-English-speaking backgrounds /“. Title page, contents and abstract only, 2000. http://web4.library.adelaide.edu.au/theses/09SSPS/09sspsb967.pdf.
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Allenstein, Jacob T. „An Investigation of Jet Engine Test Cell Exhaust Stack Aerodynamics and Performance through Scale Model Test Studies and Computational Fluid Dynamics Results“. The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586515794023938.
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Goupil, Marc Y. „Dynamic Pressure Sensing for the Flight Test Data System“. DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2115.
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This thesis describes the design, assembly, and test of the FTDS-K, a new device in the Boundary Layer Data System (BLDS) family of flight data acquisition systems. The FTDS-K provides high-frequency, high-gain data acquisition capability for up to two pressure sensors and an additional three low-frequency pressure sensors. Development of the FTDS-K was separated into a core module, specialized analog subsystem, and practical testing of the FTDS-K in a flow measurement mission. The core module combines an nRF52840-based microcontroller module, switching regulator, microSD card, real-time clock, temperature sensor, and trio of pressure sensors to provide the same capabilities as previous-generation BLDS-P devices. An expansion header is included in the core module to allow additional functionality to be added via daughter boards. An analog signal chain comprised of two-stage amplification and fourth-order active antialiasing filters was implemented as a daughter board to provide an AC-coupled end-to-end gain of 7,500 and a DC-coupled end-to-end gain of 50. This arrangement was tested in a wind tunnel to demonstrate that sensors with a full-scale range of 103 kPa can be used to reliably discriminate between laminar and turbulent flows based on pressure fluctuation differences on the order of tens of Pa. A combination of wind-off correction and band-filtering was used to reduce the effect of inherent and induced electrical noise, while two-sensor correlation was tested and shown to be effective at removing certain types of noise. Total power consumption for the FTDS-K in a representative mission is 208 mW, which translates to an operational endurance of 9 hours with 2 AAA LiFeS2 cells at -40°C.
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Sylvia, Allison M. „Test Anxiety and Reading Comprehension in Adults with Academic Difficulties“. University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1583853725075996.
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Odden, Dan Adrian. „Development of heat pipes with potassium as woking fluid: Performance limitations and test rig development“. Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18600.
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The incentive to reduce energy consumption in the industry is big, especiallyin high temperature systems. Heat pipes are of great interest for this purposedue to their favorable thermomechanical properties. This master thesis is apart of the ongoing study of Ph.D. candidate Geir Hansen, who is currentlydeveloping a rectangular heat pipe with potassium as working fluid at NTNU.The rectangular heat pipe is intended to be implemented in the walls ofelectrolysis cells as a part of a heat recovery system.The present work reports results of theoretical calculations of two importantheat transfer limitations, the incipience of boiling and the capillarylimitation for two types of nickel foam wicks. Results of experimental testscarried out on the cooling circuit for the proposed rectangular heat pipe arealso reported. The foam porosity, permeability and effective pore radius forwick 1 is 0.797, 31·10−12m2 and 62·10−6m, respectively, and for wick 2; 0.886,205·10−12m2 and 126·10−6m.A literature survey showed that porous coated surfaces improves the heattransfer and requires less superheat for boiling to commence. Calculationsperformed showed no danger of homogeneous nucleation in the proposed heatpipe. Boiling inside the nickel foam wick(s) were found to only be of concernfor wick 2 at high heat fluxes and a operating temperature of 600C.Calculations of the capillary limit showed that wick 2 is the best choicefor sustaining high heat fluxes. Increasing the wick length to 20cm madewick 2 not suitable for usage, and wick 1 was the best choice for increasedwick length. Combination of the two wick types showed to be very effectiveand significantly (factor of almost 4) improved the performance. An unevenheat flux distribution where a lower heat flux is at the bottom region of theevaporator is found to lower the performance, while a higher heat flux at thebottom region increases the performance.Early tests revealed that the PID controller was marginally stable, so thecontroller was tuned and stable operating conditions were achieved. Experimentsshowed that in order to get an accurate heat balance for the test rig,knowledge about the exact position of the thermocouples is needed.
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Korb, Samuel N. (Samuel Noaa) 1984. „Towards the manufacturing of microfluidic devices : fluid flow in multilayer devices as a test case“. Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36238.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (p. 154-158).
In this work, the area of microfluidics is analyzed for advances that could be made in the manufacturing of a microfluidic device, and then one area - the alignment of multilayer devices - is selected for greater focus. Microfluidics is an emerging technology receiving much attention to date for its potential in biological, chemical, and medical applications. It could bring costs savings and contamination-reducing disposable parts, but only if certain hurdles relating to the design and fabrication of the devices are overcome. In order to better understand the manufacturing issues, a survey of the applications is presented, with a focus on the functional requirements for the fabrication of the devices. Then, a survey of the techniques currently in use to create microfluidic devices is presented, again focusing on the issues related to their fabrication and scalability to large-volume manufacturing. In order to address the issues that arise during the surveys, two new directions are submitted. First, a "test device" is proposed. This test device will consist of a variety of sample features characteristic of many different types of microfluidic devices, in a range of carefully selected dimensions.
(cont.) The test device serves as a tool for evaluating different processes for relative capabilities in creating the microfluidic structures. Second, multilayer devices, an area of concern that will arise as the field moves forward, is explored further. Specifically, the impact on fluid flow parameters of alignment of the two layers, a process currently performed manually, is investigated. A theoretical model of the scenario, which acts as a pressure barrier to laminar flow in a rectangular channel, is established, identifying the parameter of interest, the coefficient of pressure loss across the multilayer joint between layers. Then a series of sample multilayer parts with target dimensions of 100 gm x 100 pm x 3 mm is constructed. The pressure loss coefficients were obtained as a function of the cross-sectional area of the joint, from as small as 0.71 for very large joints up to over 1000 for joints that are only 30 gm of the channel in width. Failure pressure for the devices was found to be on the order of 140 kPa.
by Samuel N. Korb.
S.M.
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Dukkipati, Ravi Kiran. „Experimental investigation of fiber sizing-test fluid interaction for in-plane permeability measurements of continuous fibers“. Thesis, Wichita State University, 2007. http://hdl.handle.net/10057/1534.
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Many manufacturers are using liquid composite molding (LCM) to manufacture composites because of its simplicity and cost effectiveness. This generic process includes techniques such as vacuum assisted resin transfer molding (VARTM), resin transfer molding (RTM), and Seemann composite reaction infusion molding (SCRIM). VARTM is most commonly used due to its low tooling cost and ease of use. One of the most important factors that affect the manufacturability of composite parts is permeability. Permeability usually affects resin flow within fibers; hence, many researchers have placed importance on the measurement of this factor in various studies. Alternate test fluids such as corn syrup, silicon oil and motor oil are being used to calculate permeability, since they are cheaper, easy to clean, and are not volatile like resins. Permeability is generally affected by fiber sizing-test fluid interaction, fiber volume fraction, and fiber orientation. In the present study, permeability effects due to fiber chemical coating or sizing were investigated using VARTM. Experiments were conducted by inducing high- and low-viscosity corn syrup and silicon oil through uni-directional glass fibers, bi-axial glass fibers, and two types of uni-directional carbon fibers, with and without sizing. Darcy’s law was used to calculate permeability. Significant permeability differences found using fibers with and without sizing are reported. Separate saturated flow rate measurements for one of the uni-directional carbon fibers and uni-directional glass fibers, both sized and unsized, were carried out by infusing corn syrup and silicon oil with similar viscosities. It was found that, over time, corn syrup displayed a gradual decrease in flow rate for saturated fiber material for constant vacuum infusion. From previous research studies, the flow rate history in the RTM process showed two stages: initial rapid flow and steady-state flow. However, in the VARTM process, the cumulative mass vs. time plot was linear. The corresponding flow rate vs. time plot showed a high initial flow rate but was decreased with time when corn syrup was used for both uni-directional glass and carbon fibers, with and without sizing. This effect was not observed in the case of silicon oil. It was concluded that corn syrup should be used with caution as a test fluid for permeability measurements until further investigations can be made.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering
"December 2007."
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Virhammar, Johan. „Idiopathic Normal Pressure Hydrocephalus : Cerebrospinal Fluid Tap Test and Magnetic Resonance Imaging as Preoperative Prognostic Investigations“. Doctoral thesis, Uppsala universitet, Neurologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-222779.
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Idiopathic normal pressure hydrocephalus (iNPH) is a condition with dilated cerebral ventricles but intracranial pressure within normal limits. The symptoms of gait impairment, cognitive decline and urinary incontinence develop gradually. Treatment with shunt insertion results in improvement in eight out of ten patients. The cerebrospinal fluid tap test (CSF TT) and preoperative magnetic resonance imaging (MRI) are methods used to select patients who may benefit from shunt surgery, but they are performed and interpreted differently in different centers throughout the world. The aim of this thesis was to evaluate the performance of the CSF TT and the underlying mechanisms of improvement in gait function after CSF removal, and to investigate the prognostic value of preoperative MRI scans. Improvement in gait and changes in cerebral blood flow (CBF) after a CSF TT were investigated in two prospective studies that included 39 and 20 patients, respectively. Gait assessment and perfusion MRI were done before and several times during the first 24 hours after a CSF TT. Perfusion was investigated with pseudo-continuous arterial spin labeling. At the group level, gait function was significantly improved at all investigation times, but only one-third of individual CSF TT responders were improved at all investigation times. In patients with increased CBF in lateral and frontal white matter after the CSF TT, gait function improved more than it did in patients with decreased CBF in these regions. However, in the whole sample, there was no significant increase in CBF after CSF removal. Preoperative MRI scans were retrospectively evaluated in 109 patients with iNPH who had undergone shunt surgery. The callosal angle was smaller in shunt responders compared with non-responders. The following findings showed the highest association with a positive outcome after shunting: a small callosal angle, wide temporal horns, and occurrence of disproportionally enlarged subarachnoid space hydrocephalus. In conclusion, CBF in white matter close to the lateral ventricles may play a role in the reversibility of symptoms after CSF removal in patients with iNPH. The CSF TT should be reevaluated if the patient does not initially improve, and preoperative MRI investigations can add prognostic information regarding the selection of shunt candidates.
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Dukkipati, Ravi Kiran Soschinske Kurt A. „Experimental investigation of fiber sizing-test fluid interaction for in-plane permeability measurements of continuous fibers /“. Thesis, A link to full text of this thesis in SOAR, 2007. http://hdl.handle.net/10057/1534.
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Jadwani, Vishal. „Development of a Method to Prepare a Test Fluid with Soft Particles in Biodiesel Fuel Blends“. Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279998.
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Bilindustrin är en av de största bidragsgivarna till koldioxidutsläpp genom fordonsutsläppnär de används. För att göra transportsektorn mer hållbar EU-politik dikterar att inkludera enhögre andel förnybara energikällor i den totala energiförbrukningen och ett sätt att uppnå det äratt införliva biobränslen i de traditionella fossila bränslena. Detta skulle minskakoldioxidavtrycket som genereras av bilindustrin på ett ekonomiskt sätt utan att göra storatekniska modifieringar i befintliga motorer. Scania AB har optimerat sitt bränslesystem för attuppfylla 10% blandning av biodiesel i normalt dieselbränsle.Scania AB är en lastbiltillverkare i Sverige med deras forsknings- och utvecklingscenterbeläget i Södertälje. De söker en lösning för att effektivisera sina bränslefilter i lastbilsmotorerför att filtrera bort mjuka partiklar som genereras på grund av nedbrytning av biobränsle. Syftetmed detta projekt kan delas upp i två huvudfaser; den första fasen är att utveckla en metod för attsimulera bränsleåldring och nedbrytning av biodiesel vilket leder till bildning av mjuka partiklarvid laboratorieförhållanden. Den senare fasen skulle vara att använda resultat från den förstafasen för att generera ett håravbrutet bränsle som därefter skulle användas för testning i enfullständig filtreringsrigg för att bedöma effektiviteten hos Scania-bränslefilter. Dessa testerskulle ge en inblick i befintliga filterprestanda beträffande nedbrutet bränsle och därmed kundebättre filter utformas för att effektivt hantera mjuka partiklar.I detta avhandlingsprojekt diskuteras olika iterationer och metoder för bildning av mjukapartiklar. Ett viktigt antagande baserat på verkliga deponeringsformationer från lastbilar överhela världen är att kalcium är en av de viktigaste orsakerna till bildning av mjuka partiklar.Resultat och bevis från tidigare avhandlingsprojekt har använts, modifierats och utvidgats i dettaprojekt. Nya metoder har utvecklats baserat på empiriska bevis från experimenten somgenomfördes under detta projekt som skulle förbättras ytterligare när Scania fortskrider meddetta projekt. Ett huvudkrav för ett håligt nedbrutet bränsle var att göra det stabilt när det gällersuspension av mjuka partiklar i biodieseln utan användning av konstant omröring för att simuleraförhållandena för bränsletanken i en lastbil.Resultaten som presenteras i detta avhandlingsprojekt är den optimerade metoden förframgångsrikt att producera mjuka partiklar och en arbetsmetod för att förberedatestbränslekoncentrat. Analys har utförts på testbränslekoncentrat i detta projekt för attkontrollera testfluidens livskraft för att utföra experiment på filtreringsrigg. Det har konstateratsatt tiofaldigt utspädningstestbränsle är det mest lovande provbränsleprovet som kan framställasmed de givna villkoren och tidsbegränsningarna.The automobile industry is one of the largest contributors to carbon emissions through vehicularemissions when in use. To make the transport sector more sustainable EU policies dictate toinclude a higher share of renewables in total energy consumption and one way to achieve that isto incorporate biofuels in the traditional fossil fuels. This would reduce carbon footprintgenerated by the automobile industry in an economical manner without making majortechnological modifications in existing engines. Scania AB has optimized their truck fuel systemto comply with the 10% blend of biodiesel in normal diesel fuel.Scania AB is a truck manufacturer in Sweden, with their research and development centresituated in Södertälje. They seek a solution to make their fuel filters in truck engines efficient tofilter out soft particles generated due to biofuel degradation. The aim of this project can bedivided in two major phases; the first phase is to develop a method to simulate fuel ageing anddegradation of biodiesel leading to formation of soft particles at laboratory conditions. The laterphase would be to use results from the first phase to generate a mock degraded fuel that would besubsequently used for testing in a full size filtration rig to assess the efficacy of Scania fuelfilters. These tests would give an insight about existing filters performance regarding degradedfuel and thus better filters could be designed to efficiently handle soft particles.In this thesis project, different iterations and methods of formation of soft particles arediscussed. An important assumption based on real deposit formations from trucks across theworld is that calcium is one of major causes of soft particles formation. Results and evidencefrom previous thesis projects have been used, modified and extended in this project. Newmethods have been developed based on empirical evidence from the experiments conductedduring this project which would be further improved as Scania progresses with this project. Amajor requirement for a mock degraded fuel was to make it stable in terms of suspension of softparticles in the biodiesel without a use of constant agitation in order to simulate the conditions ofthe fuel tank in a truck.The results presented in this thesis project are the optimized method to successfullyproduce soft particles and a working method to prepare test fuel concentrate. Analysis has beenperformed on test fuel concentrate in this project to check for viability of test fluid forconducting experiments on filtration rig. It has been concluded that 10 folds dilution test fuel isthe most promising test fuel sample that can be prepared with the given conditions and timerestrictions
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Couval, Romain. „Scale up of a test fluid for testing the fuel system robustness against soft particles in biodiesels“. Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-85745.
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The future of fuels will most probably be a mixture of different fuels, called drop-in fuels. It is already known that these drop-in fuels will lead to solubility issues, with creation of deposit on crucial fuel system parts, due to the formation of soft particles. The fuel system of the future should be robust against any type of soft particles. Today, there is no scaled up test fluid existing for testing full scale fuel systems. The objective of this thesis was to develop a scaled up test fluid which is a key element to the development of a test method to enhance the fuel system robustness against soft particles. A test fluid was achieved by a concentrate of calcium soap diluted two thousand times to reach a volume of 1000 litres with a concentration of 1,4 ppm. The concentration was measured by gas chromatography mass spectroscopy method following a derivatisation as sample preparation. The formation of the concentrate was established by changing the type of fuel, the level of aging, the amount of calcium and other counterions and eventually by addition of third elements. The concentrate was made of aged B100, calcium oxide powder and water. The test fluid was made by diluting the concentrate with fresh B7 and a protocol to characterise the stability of this test fluid was developed. This test fluid was tested under real condition in a filter rig giving homogeneous concentration all along the experiment, which confirmed the stability of the test fluid.
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Chan, Fiona. „Development of matrices abstract reasoning items to assess fluid intelligence“. Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/277914.
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Matrices reasoning tests, which contain missing pieces in matrices that participants attempt to figure out, are one of the most popular types of tests to measure general intelligence. This thesis introduces several methods to develop matrices items, and presents them in different test forms to assess general intelligence. Part 1 introduces the development of a matrices test with reference to Carpenter’s five rules of Raven’s Progressive Matrices. The test items developed were administered together with the Standard Ravens’ Progressive Matrices (SPM). Results based on confirmatory factor analysis and inter-item correlation demonstrate good construct validity and reliability. Item characteristics are explored with Item-Response Theory (IRT) analyses. Part 2 introduces the development of a large item bank with multiple alternatives for each SPM item, with reference to the item components of the original SPM. Results showed satisfactory test validity and reliability when using the alternative items in a test. Findings also support the hypothesis that the combination of item components accounts for item difficulty. The work lays the foundation for the future development of computer adaptive versions of Raven’s Progressive Matrices. Part 3 introduces the development of an automatic matrix item generator and illustrates the results of the analyses of the items generated using the distribution-of-three rule. Psychometric properties of the items generated are explored to support the validity of the generator. Figural complexity, features, and the frequency at which certain rules were used are discussed to account for the difficulty of the items. Results of further analyses to explore the underlying factors of the difficulty of the generated items are presented and discussed. Results showed that the suggested factors explain a substantial amount of the variance of item difficulty, but are insufficient to predict the item difficulty. Adaptive on-the-fly item generation is yet to be possible for the test at this stage. Overall, the methods for creating matrices reasoning tests introduced in the dissertation provide a useful reference for research on abstract reasoning and fluid intelligence measurements. Implications for other areas of psychometric research are also discussed.
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Bergstrand, David. „Investigation of Internal Diesel Injector Deposits on fuel injector performance for proposal of injector test rig test method“. Thesis, Uppsala universitet, Elektricitetslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-417012.
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With increasing demands for lowering emissions from diesel engines, bio fuel has been introduced to the fuel mixture. This fuel is based on vegetable oil with a much smaller carbon footprint than fossil fuel. The chemical composition of bio fuel has lead to deposits forming inside the fuel injector in diesel engines, these deposits are usually denoted as Internal Diesel Injector Deposits (IDID). At Scania CV AB an injector test rig is designed with the goal of creating and investigating IDID. This project has made a theoretical investigation of how IDID are formed and how this affects the mechanics inside the injector. It has also analysed injector components from a worst case scenario perspective in order to find a testing method for creating IDID in the test rig. By analysing performance changes from a build-up perspective, where IDID decreases the tolerances inside the injector, as well as friction, formed when deposits cause injector mechanics to stick together, it has been found that injector performance does hardly change from build-up and that performance changes only occur when friction is introduced. From the injector component analysis it is found that the limiting factors in rig testing come from fuel system components rather than the injector itself. This is the base for a rig running test method presented.
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Koyama, Tomofumi. „Numerical modelling of fluid flow and particle transport in rough rock fracture during shear“. Licentiate thesis, Stockholm : Mark och vatten, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-512.
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Wang, Meng (Rachel), Per Danzl, Vishal Mahulkar, Damrongrit (Neng) Piyabongkarn und Paul Brenner. „A hydraulic test stand for demonstrating the operation of Eaton’s energy recovery system (ERS)“. Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-199521.
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Fuel cost represents a significant operating expense for owners and fleet managers of hydraulic off-highway vehicles. Further, the upcoming Tier IV compliance for off-highway applications will create further expense for after-treatment and cooling. Solutions that help address these factors motivate fleet operators to consider and pursue more fuelefficient hydraulic energy recovery systems. Electrical hybridization schemes are typically complex, expensive, and often do not satisfy customer payback expectations. This paper presents a hydraulic energy recovery architecture to realize energy recovery and utilization through a hydraulic hydro-mechanical transformer. The proposed system can significantly reduce hydraulic metering losses and recover energy from multiple services. The transformer enables recovered energy to be stored in a high-pressure accumulator, maximizing energy density. It can also provide system power management, potentially allowing for engine downsizing. A hydraulic test stand is used in the development of the transformer system. The test stand is easily adaptable to simulate transformer operations on an excavator by enabling selected mode valves. The transformer’s basic operations include shaft speed control, pressure transformation control, and output flow control. This paper presents the test results of the transformer’s basic operations on the test stand, which will enable a transformer’s full function on an excavator.
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KRUTZ, JILL E. „DESIGN OF A HYDRAULIC ACTUATOR TEST STAND FOR NON-LINEAR ANALYSIS OF HYDRAULIC ACTUATOR SYSTEM“. University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990813095.
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Andersson, Nina. „Cerebrospinal fluid infusion methods : development and validation on patients with idiopathic normal pressure hydrocephalus“. Doctoral thesis, Umeå : Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1359.
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Swanson, Erik Evan. „Design and Evaluation of an Automated Experimental Test Rig for Determination of the Dynamic Characteristics of Fluid-Film Bearings“. Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30727.
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Hydrodynamic journal bearings are applied in a wide range of both old and new, advanced
rotating machinery designs. To maintain existing machinery, as well as to design new, state of the
art machines, validated analytical models for these bearings are needed. This work documents the
development and evaluation of an automated test rig for the evaluation of hydrodynamic journal
bearings to provide some of the needed experimental data. This work describes the test rig in
detail, including the results of experimental characterization of many of the test rig subsystems.
Experimental data for a two axial groove bearing and a pressure dam bearing under steady load
conditions are presented for a range of loads at two different shaft speeds. Experimental data and
analytical results for dynamic loading are also discussed. The work concludes with a summary of
the state of the test rig and recommendations for further work.Ph. D.
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Ehrmann, Robert S. „Development of Measurement Methods for Application to a Wind Tunnel Test of an Advanced Transport Model“. DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/369.
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California Polytechnic State University, San Luis Obispo is currently working towards developing a Computational Fluid Dynamics (CFD) database for future code validation efforts. Cal Poly will complete a wind tunnel test on the Advanced Model for Extreme Lift and Improved Aeroacoustics (AMELIA) in the National Full-Scale Aerodynamics Complex (NFAC) 40 foot by 80 foot wind tunnel at NASA Ames Research Center in the summer of 2011. The development of two measurement techniques is discussed in this work, both with the objective of making measurements on AMELIA for CFD validation.
First, the work on the application of the Fringe-Imaging Skin Friction (FISF) technique to AMELIA is discussed. The FISF technique measures the skin friction magnitude and direction by applying oil droplets on a surface, exposing them to flow, measuring their thickness, and correlating their thickness to the local skin friction. The technique has the unique ability to obtain global skin friction measurements. A two foot, nickel plated, blended wing section test article has been manufactured specifically for FISF. The model is illuminated with mercury vapor lamps and imaged with a Canon 50D with a 546 nm bandpass filter. Various tests are applied to the wing in order to further characterize uncertainties related with the FISF technique. Human repeatability has uncertainties of ±2.3% of fringe spacing and ±2.0° in skin friction vector direction, while image post processing yields ±25% variation in skin friction coefficient. A method for measuring photogrammetry uncertainty is developed. The effect of filter variation and test repeatability was found to be negligible. A validation against a Preston tube was found to have 1.8% accuracy.
Second, the validation of a micro flow measurement device is investigated. Anemometers have always had limited capability in making near wall measurements, driving the design of new devices capable of measurements with increased wall proximity. Utilizing a thermocouple boundary layer rake, wall measurements within 0.0025 inches of the surface have been made. A Cross Correlation Rake (CCR) has the advantage of not requiring calibration but obtaining the same proximity and resolution as the thermocouple boundary layer rake. The flow device utilizes time of flight measurements computed via cross correlation to calculate wall velocity profiles. The CCR was designed to be applied to AMELIA to measure flow velocities above a flap in a transonic flow regime. The validation of the CCR was unsuccessful. Due to the fragile construction of the CCR, only one data point at 0.10589 inches from the surface was available for validation. The subsonic wind tunnel’s variable frequency drive generated noise which could not be filtered or shielded, requiring the use of a flow bench for validation testing. Since velocity measurements could not be made in the flow bench, a comparison of a fast and slow velocity was made. The CCR was not able to detect the difference between the two flow velocities. Currently, the CCR cannot be applied on AMELIA due to the unsuccessfully validation of the device.
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Kuoppala, Oskar. „Cavitation analysis on test rig. : An experimental and CFD study executed in collaboration with Epiroc AB“. Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-188337.
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This master thesis project was done in collaboration with Epiroc Group Ab. Epiroc supplies high-quality drills of various types that can be used both above and below ground. A major problem in their percussive rock drills is that that cavitation is formed. Cavitation is a phenomenon that occurs when a fluid is subject to a sudden pressure drop. This pressure drop causes the liquid to vaporize and create gas bubbles. These gas bubbles will cause erosion to the walls when imploded. These cavitation damages lead to drills breaking and parts having to be replaced preserved. An experimental rig was used to create cavitation. From the experimental rig, it was possible to measure the hydraulic transients that are created when the valve was closed. In this study, we examined whether one can visually see these damages occurring inside the pipe on valve parts that are subjected to these cavitation damages. CFD simulations were used to re-create the closing of the valve in the experimental rig. By exporting pressure data from the experiments one could compare the numerical result to the experimental data. It was also investigated if it is possible to see some connection between the gas formation and the damages seen visually from the experimental part. For the simulation the realizable k − ε methods were implemented with enhanced wall treatment. The mixture model was used since we have a multi-phase flow. Some visual damages were recognized during the experiments. However, no distinguished pattern or specific areas was established. From the simulations, it could be determined that they generated gas when the valve was closed. However, the pressure transients could not be replicated in the numerical result.
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Struwig, Daniel Johannes. „The development and verification of a centrifugal compressor test bench“. Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86250.
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Thesis (MScEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Turbomachinery plays an important role in the efficiency of power generation and combustion processes used in the automotive and aerospace industries. The potential for fulfilling future energy needs has been identified in both civilian and military applications, for example micro gas turbines (MGTs) used in unmanned aireial vehicles (UAVs). The goal of this thesis was to build a performance testing facility for small-scale centrifugal compressors, for use in MGTs. The objectives of this study were mainly achieved through experimental work. In addition to the experimental work, numerical simulations using computational fluid dynamics (CFD) software were performed to substantiate the experimental results. The project methodology followed the process whereby a compressor performance map is constructed from experimental data and compared to map obtained from theoretical data. The test facility consists of a turbocharger fitted with an experimental compressor section. The turbocharger turbine is driven by unheated compressed air. Sensors, data acquisition and ancillary equipment required to perform performance test measurements, were obtained and installed on the test facility. Performance curves at three different rotational speeds were successfully obtained for the experimental compressor. When compared to the CFD results there was good qualitative agreement, although deviations in the results increased with rotational speed. In addition a second impeller design was tested which correlated well with the theoretical data.
AFRIKAANSE OPSOMMING: Turbomasjinerie speel 'n belangrike rol in die doeltre endheid van kragop- wekking en verbrandingsprosesse wat in die motor- en lugvaartbedryf gebruik word. Die potensiaal om in toekomstige energiebehoeftes te voorsien is in beide burgerlike en militêre toepassings uitgewys, byvoorbeeld mikrogastur- bines (MGT's) wat in onbemande vliegtuie (OLV's) gebruik word. Die doel met hierdie tesis was om 'n prestasietoetsfasiliteit vir kleinskaalse sentrifu- gale kompressors te bou wat in MGT's gebruik kan word. Die doelstellings van hierdie studie is hoofsaaklik deur eksperimentele werk behaal. Daarbe- newens is numeriese simulasies met gebruikmaking van sagteware vir bereke- ningsvloeidinamika (BVD) gedoen om die eksperimentele resultate te staaf. Die projekmetodologie volg die proses om 'n kompressorprestasiekaart uit eks- perimentele data op te stel en dit te vergelyk met 'n kaart wat uit teoretiese data bekom is. Die toetsfasiliteit bestaan uit 'n turboaanjaer wat met 'n eksperimentele kompressordeel toegerus is. Die turboaanjaer se turbine word deur onverhitte druklug aangedryf. Sensors, dataverwerwing en bykomstige toerusting, wat benodig is om prestasietoetsmetings mee te doen, is bekom en op die toetsfasiliteit geïnstalleer. Prestasiekrommes is vervolgens by drie verskillende omwentelingsnelhede suksesvol met die eksperimentele kompres- sor bekom. In vergelyking met die BVD-resultate was daar goeie kwalitatiewe ooreenstemming, ofskoon afwykings in die resultate vergroot het namate die omwentelingspoed toegeneem het. Daarby is 'n tweede stuwerontwerp getoets wat goed met die teoretiese resultate korreleer.
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Ozgen, Onur. „Design Improvements On Mixed Flow Pumps By Means Of Computational Fluid Dynamics“. Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12608093/index.pdf.
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The demand on high efficiency pumps leads the manufacturers to develop new design and manufacturing techniques for rotodynamic pumps. Computational Fluid
Dynamics (CFD) software are started to be used during the design periods for this reason in order to validate the designs before the pumps are produced. However the integration process of CFD software into the design procedure should be made carefully in order to improve the designs.
In this thesis, the CFD software is aimed to be integrated into the pump design procedure. In this frame, a vertical turbine type mixed flow pump is aimed to be designed and design improvements are intended to be made by applying numerical
experimentations on the pump. The pump that is designed in this study can deliver 115 l/s flow rate against the head of 16 mWC in 2900 rpm. The effects of various parameters in the design are investigated by the help of CFD software during the
design and best performance characteristics of the pump are aimed to be reached.
The pump that is designed in this study is manufactured and tested in Layne Bowler Pumps Company Inc. The design point of the pump is reached within the tolerance limits given in the related standard.
In addition, the results of actual test and numerical experimentation are compared and found to be in agreement with each other. The integration of CFD code to the design procedure is found quite useful by means of shortening design periods, lowering manufacturing and testing costs. In deed the effects of the design parameters are understood better by applying numerical experimentations to the designed pump.
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Weidner, Katherine Lourene. „Evaluation of the Jet Test Method for determining the erosional properties of Cohesive Soils; A Numerical Approach“. Thesis, Virginia Tech, 2012. http://hdl.handle.net/10919/72983.
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Estimates of bank erosion typically require field measurements to determine the soil erodibility since soil characteristics are highly variable between sites, especially for cohesive soils. The submerged jet test device is an in situ method of determining the critical shear stress and soil erodibility of cohesive soils. A constant velocity jet, applied perpendicular to the soil surface, creates a scour hole which is measured at discrete time intervals. While the results of these tests are able to provide values of critical shear stress and soil erodibility, the results are often highly variable and do not consider certain aspects of scour phenomena found in cohesive soils. Jet test measurements taken on the lower Roanoke River showed that the results varied for samples from similar sites and bulk failures of large areas of soil were common on the clay banks. Computational Fluid Dynamics (CFD) can be used to determine the effect of scour hole shape changes on the applied shear stress. Previous calculation methods assumed that the depth of the scour hole was the only parameter that affected the applied shear stress. The analysis of the CFD models showed that depth did heavily influence the maximum shear stress applied to the soil boundary. However, the scour hole shape had an impact on the flow conditions near the jet centerline and within the scour hole. Wide, shallow holes yielded results that were similar to the flat plate, therefore it is recommended that field studies only use jet test results from wide, shallow holes to determine the coefficient of erodibility and the critical shear stress of cohesive soils.
Master of Science
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Meng, Li. „Development of one-step strip test for rapid detection of antibiotic residues in animal body fluid and food animal products /“. View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?BIEN%202006%20MENG.
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DeJager-Kennedy, Robin. „Semi-Analytical Analysis of Hand-Arm Vibration and Bench-Top Fluid Flow Test to Understand Vibration Effect on Vascular Disorder“. University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282062413.
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Rowan, D. „Design and development of a high-speed test facility and the measurement of the fluid film characteristics of journal bearings“. Thesis, Cranfield University, 1998. http://dspace.lib.cranfield.ac.uk/handle/1826/11357.
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In the theoretical analysis of high speed rotor bearing systems, it is common to use
four displacement and four velocity based coefficients, which characterise the
behaviour of the lubricating fluid film. Although a great deal of work has been
published establishing theoretical models of all types of hydrodynamic journal bearings,
the large amount of experimental work has centred on relatively low speed conditions.
This work presents a contribution to the experimental study of the static and dynamic
characteristics of oil films in journal bearings used in high-speed rotating machinery.
The main objectives of the work are:
• To devise new experimental techniques for the measurement of dynamic
coefficients suitable for use at high rotational speeds
• To design, manufacture, assemble and commission a test facility to measure
the static and dynamic characteristics of journal bearings at speeds up to
30000 rpm
• To determine the static and dynamic characteristics of a 5 Pad Tilting Pad
Journal Bearing Unit of 80 mm diameter at speeds up to 25 000 rpm using the
said test facility.
New techniques are particularly necessary for the measurement of velocity coefficients
because these invoke the necessity of imposing a velocity on to the bearing housing
and previous techniques have utilised synchronous motion of the bearing.
Consequently a new experimental procedure for measuring the four velocity or
damping coefficients of an oil film journal bearing from imposed dynamic "orbits" has
been devised called the "double pulse" technique. All four velocity coefficients are
derived from one imposed journal centre dynamic orbit and, therefore may be regarded
as being obtained at the same time. The method requires the production of a "cross-
over" point similar to that of a "figure of eight" shaped orbit and utilises the "cross-over"
point therein.
Coefficients are initially evaluated in a co-ordinate system, which is chosen to align with
the designated parts of the measured orbit. Each coefficient is then evaluated from
single values of instantaneous imposed force and resulting journal centre velocity.
Coefficients are them converted into any other desired axes system. The result is a
simpler experimental procedure, with reduced uncertainty compared to hitherto existing
methods.
The use of non-sinusoidal excitation of the oil film was explored, in the form of applying
a step-pulse train load pattern to produce a cross-over pattern in the journal
displacement ·orbit'.
Experimental tests were completed on a tilting pad bearing at speeds up to 15 000 rpm
inclusive. At speeds above this, the bearing exhibited a vibrational response, which
precluded the accurate measurement of journal centre displacement.
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Yang, Qing. „A computational fluid dynamic approach and Monte Carlo simulation of phantom mixing techniques for quality control testing of gamma cameras“. Thesis, University of Canterbury. Physics and Astronomy, 2013. http://hdl.handle.net/10092/8742.
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In order to reduce the unnecessary radiation exposure for the clinical personnel, the optimization of procedures in the quality control test of gamma camera was investigated. A significant component of the radiation dose in performing the quality control testing is handling phantoms of radioactivity, especially the mixing to get a uniform activity concentration. Improving the phantom mixing techniques appeared to be a means of reducing radiation dose to personnel. However, this is difficult to perform without a continuous dynamic tomographic acquisition system to study mixing the phantom.
In the first part of this study a computational fluid dynamics model was investigated to simulate the mixing procedure. Mixing techniques of shaking and spinning were simulated using the computational fluid dynamics tool FLUENT. In the second part of this study a Siemens E.Cam gamma camera was simulated using the Monte Carlo software SIMIND. A series of validation experiments demonstrated the reliability of the Monte Carlo simulation. In the third part of this study the simulated the mixing data from FLUENT was used as the source distribution in SIMIND to simulate a tomographic acquisition of the phantom. The planar data from the simulation was reconstructed using filtered back projection to produce a tomographic data set for the activity distribution in the phantom. This completed the simulation routine for phantom mixing and verified the Proof-in-Concept that the phantom mixing problem can be studied using a combination of computational fluid dynamics and nuclear medicine radiation transport simulations.
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Murray, A. „A critical study of the application of the fluid bridge test before, during and after surgery for stress incontinence in women“. Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384350.
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Langenhoven, Jacobus. „The effects of humidity and soluble water content on the lubricity testing of a n-hexadecane and palmitic acid test fluid“. Diss., University of Pretoria, 2014. http://hdl.handle.net/2263/46242.
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Liquid fuel lubricity testing is known to be sensitive to the humidity of the surrounding atmosphere. The effect reported does however not seem to be universal for all diesel types according to available literature. This study was limited to the use of n-hexadecane as base fluid with addition of between 100 - 2000 ppm of palmitic acid (PA) as lubricity enhancer. The fuel spectrum was kept simple to allow a more fundamental approach by limiting the extent of possible chemical reactions. Both wear and seizure load testing were performed.
The effect of water on both tests was found to be:
Wear and friction increased with higher soluble water content. Water therefore interferes with the action of the lubricating additive leading to decreased performance.
It is known that hydroxyl groups, from dissociative chemisorption of water, act as active sites for adsorption. It is however postulated that the associative chemisorption and/or physisorption of water interferes by either reducing the active site availability or reducing activity to ligand exchange.
No iron oxyhydroxides (FeOOH) were detected on the wear scars or tracks using Raman spectroscopy. The adsorbed water therefore likely only interact with the surface due to their low concentrations (10 ~ 50 ppm).Liquid fuel lubricity testing is known to be sensitive to the humidity of the surrounding atmosphere. The effect reported does however not seem to be universal for all diesel types according to available literature. This study was limited to the use of n-hexadecane as base fluid with addition of between 100 - 2000 ppm of palmitic acid (PA) as lubricity enhancer. The fuel spectrum was kept simple to allow a more fundamental approach by limiting the extent of possible chemical reactions. Both wear and seizure load testing were performed.
The effect of water on both tests was found to be:
Wear and friction increased with higher soluble water content. Water therefore interferes with the action of the lubricating additive leading to decreased performance.
It is known that hydroxyl groups, from dissociative chemisorption of water, act as active sites for adsorption. It is however postulated that the associative chemisorption and/or physisorption of water interferes by either reducing the active site availability or reducing activity to ligand exchange.
No iron oxyhydroxides (FeOOH) were detected on the wear scars or tracks using Raman spectroscopy. The adsorbed water therefore likely only interact with the surface due to their low concentrations (10 ~ 50 ppm). For wear testing the following additional observations were made:
The electric contact resistance (ECR) took longer to increase at higher soluble water content, for all PA concentrations. The equilibrium values attained were also lower, when values were within the measurement range. This again highlights the reduced lubricity performance at higher soluble water content.
Wear scar appearance and colour were uniquely affected at each concentration of PA
Similar trends were observed at 60 °C and 80 °C. At the higher temperature:
Wear scar diameters increased.
Friction coefficients decreased and had less variance.
ECR values were similar, but took longer to increase to a steady value.
For seizure load testing the following additional observations were made:
At higher water content, the oscillation-stroke on the test machine used tended to deviate more, before the actual seizure point was reached.
The effects of soluble water were more noticeable at lower PA concentrations.Dissertation (MEng)--University of Pretoria, 2014.
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Chemical Engineering
MEng
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Eisenträger, Almut. „Finite element simulation of a poroelastic model of the CSF system in the human brain during an infusion test“. Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:372f291f-cf36-48ef-8ce8-d4c102bce9e3.
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Cerebrospinal fluid (CSF) fills a system of cavities at the centre of the brain, known as ventricles, and the subarachnoid space surrounding the brain and the spinal cord. In addition, CSF is in free communication with the interstitial fluid of the brain tissue. Disturbances in CSF dynamics can lead to diseases that cause severe brain damage or even death. So-called infusion tests are frequently performed in the diagnosis of such diseases. In this type of test, changes in average CSF pressure are related to changes in CSF volume through infusion of known volumes of additional fluid. Traditionally, infusion tests are analysed with single compartment models, which treat all CSF as part of one compartment and balance fluid inflow, outflow and storage through a single ordinary differential equation. Poroelastic models of the brain, on the other hand, have been used to simulate spatial changes with disease, particularly of the ventricle size, on larger time scales of days, weeks or months. Wirth and Sobey (2008) developed a two-fluid poroelastic model of the brain in which CSF pressure pulsations are linked to arterial blood pressure pulsations. In this thesis, this model is developed further and simulation results are compared to clinical data. At first, the functional form of the compliance, which governs the storage of CSF in single compartment models, is examined by comparison of two different compliance models with clinical data. The derivations of a single-fluid and a two-fluid poroelastic model of the brain in spherical symmetry are laid out in detail and some of the parameters are related to the compliance functions considered earlier. The finite element implementation of the two-fluid model is described and finally simulation results of the average CSF pressure response and the pressure pulsations are compared to clinical data.
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Tshuma, Mboneni Ona. „An exploration of the perceptions and experiences of community members on acceptability and feasibility of HIV Self-Testing Oral Fluid Test in Neta ward Mberengwa District, Zimbabwe“. University of the Western Cape, 2018. http://hdl.handle.net/11394/6875.
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Master of Public Health - MPHBackground: The identification of undiagnosed HIV positive individuals through HIV testing services is one of the key measures in ensuring that the UNAIDS/ WHO 90 90 90 targets are achieved by the year 2020. The identification and subsequent initiation of HIV positive individuals on ART helps to minimise or prevent HIV transmission following viral suppression. Around 25% of people living with HIV globally are unaware of their positive status. In many countries, critical gaps exist in HIV services including prevention, testing and treatment. In Africa, the East and Southern region has a high burden of HIV/ AIDS where 50% of people are living with HIV, with 800,000 new infections in 2017. Despite concerted efforts in rolling out HIV testing services in Zimbabwe, a significant number of the population, especially men and young people, remain with an unknown HIV status, which is hindering progress towards the control and prevention of the HIV pandemic. A recent study confirmed that HIV testing in men is lower as compared to women. Consequently, progress is slower in trying to achieve the year 2020 milestone. The identification of suitable options for reaching out to these groups and the general population is important to achieve a reduction HIV prevalence. HIV self-testing oral fluid sample is thought to have the capacity to increase uptake of HIV testing. However, it still requires evidence on its acceptability and feasibility for those with undiagnosed HIV. Aim: The aim of this study was to explore the perceptions and experiences of the accessibility and feasibility HIV self-testing kits for individuals who received and used this method in Neta ward in Mberengwa District, Zimbabwe. The study identified some key factors that led to individuals accepting the kits and using them. The findings of this study will hopefully be able to inform policy makers’ decision-making about the importance of rolling out HST in the country.
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Ying, Pei. „Aerodynamic analysis of a novel wind turbine for an omni-flow wind energy system“. Thesis, University of Hertfordshire, 2016. http://hdl.handle.net/2299/17355.
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The purpose of this research is to propose a novel wind turbine for an omni-flow wind energy system and investigate its aerodynamic performance. The geometry of the novel wind turbine is based upon the impulse turbine technology which has been successful in wave energy. In this study, both numerical and experimental studies were conducted to evaluate the aerodynamic features of this wind turbine. The numerical method was validated by a comparison between numerical and experimental results over a range of tip speed ratios. Results obtained from experiments and simulations indicate that the proposed wind turbine can be employed. Additionally, on the basis of the analyses performed, this new wind turbine has the potential for having a good startup feature, which means that this wind turbine can be suitable for applications in an urban environment. As an important component, the stator of this wind turbine can increase the passing flow velocity by 20%. Meanwhile, the passing flow direction also can be optimised by the stator. Aerodynamics of the wind turbine was analysed under the non-uniform flow condition, because the flow is non-uniform inside the omni-flow wind energy system. It was found that the maximum power coefficient of such a turbine under the non-uniform flow condition is lower than that under the uniform flow condition. Due to the non-uniform flow, the blades experience different flow velocities, and as a consequence, undergo different aerodynamic loads during one operation cycle. Thus the generated torque and thrust on a blade are subjected to frequent and periodical changes. Influences of the geometrical parameters on the aerodynamic characteristics of this wind turbine were investigated. From the initial study, it was found that changes of hub-to-tip ratios, numbers of blades, aerofoils and numbers of guide vanes, can significantly affect the II power performance. Additionally, the wind turbine obtained high values of maximum torque coefficients with changing geometrical parameters.
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Jingami, Naoto. „Two-Point Dynamic Observation of Alzheimer’s Disease Cerebrospinal Fluid Biomarkers in Idiopathic Normal Pressure Hydrocephalus“. Kyoto University, 2020. http://hdl.handle.net/2433/253481.
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Manivannan, Sivaprasath. „Measuring permeability vs depth in the unlined section of a wellbore using the descent of a fluid column made of two distinct fluids : inversion workflow, laboratory & in-situ tests“. Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX086/document.
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Dans les puits de production d’eau, de pétrole, de gaz et de chaleur géothermique, ou dans les puits d’accès à un stockage d’hydrocarbures, il est précieux de connaître la perméabilité de la formation ou de sa couverture en fonction de la profondeur, soit pour améliorer le modèle de réservoir, soit pour choisir les zones dans lesquelles procéder à des opérations spéciales.On propose une technique qui consiste à balayer la hauteur du découvert par une interface entre deux liquides de viscosités très contrastées. Le débit total qui pénètre la formation à chaque instant est ainsi une fonction de la position de l’interface et de l’historique des pressions dans le puits. On doit alors résoudre un problème inverse : rechercher la perméabilité fonction de la profondeur à partir de l’historique des débits dans le temps. Dans la pratique, le puits est équipé d’un tube central. Le balayage est effectué par injection d’un liquide à pression d’entrée constante dans le tube central et soutirage d’un autre liquide par l’espace annulaire. On mesure les débits d’injection et de soutirage dont la différence est le débit qui entre dans la formation.Pour valider et améliorer cette technique, on a d’abord utilisé une maquette simulant un découvert multi-couches disponible au LMS. On a exploité aussi des essais en place réalisés dans la couverture peu perméable d’un stockage souterrain de gaz. Dans ces essais, un liquide visqueux placé dans le découvert était déplacé par un liquide moins visqueux (méthode dite « opening »). Les couches plus perméables étaient correctement identifiées (Manivannan et al. 2017), mais une estimation quantitative était un défi en raison des phénomènes transitoires qui affectent le voisinage immédiat des puits. De plus, le rayon investigué dans le massif était petit.La thèse a relevé ces défis en proposant un essai légèrement différent et une nouvelle technique d’interprétation. Les essais avec une maquette modifiée ont montré la supériorité d’une méthode « closing » dans laquelle le puits est d’abord rempli du liquide le moins visqueux. On ménage une période de stabilisation avant l’injection du liquide visqueux pour réduire les effets transitoires ; elle permet aussi d’estimer la perméabilité moyenne et l’influence de la zone endommagée à la paroi (le « skin »).Puis on conduit l’essai proprement dit. L’historique des débits mesurés en tête de puits constitue le profil d’injection dont on déduit le profil de perméabilité.. Cette estimation suppose un écoulement monophasique dans chaque couche et la même « skin » pour toute la formation. Les incertitudes principales portent sur les pressions de formation et les variations possibles du « skin ». Elles sont estimées au moyen d’un calcul analytique. On a vérifié sur la maquette que les profils de perméabilité estimés présentent une bonne concordance avec les perméabilités mesurées avant les essais.On a réalisé un essai sur un sondage de 1750 m de long atteignant une couche de sel dont on a correctement estimé la perméabilité moyenne pendant la période de stabilisation. Toutefois elle était si faible (4.0E-21 m²) que l’utilisation de deux fluides n’a pas permis de faire une différence entre les diverses parties du puitsIn wells producing water, oil, gas or geothermal energy, or in access wells to hydrocarbon storage, it is critical to evaluate the permeability of the formation as a function of depth, to improve the reservoir model, and also to identify the zones where additional investigation or special completions are especially useful.A new technique is proposed, consisting of scanning the open hole (uncased section of the wellbore) with an interface between two fluids with a large viscosity contrast. The injection rate into the formation depends on interface location and well pressure history. An inverse problem should be solved: estimate permeability as a function of depth from the evolution of flow rates with time. The wells are usually equipped with a central tube. The scanning is done by injecting a liquid in the central tube at constant wellhead pressure. Injection and withdrawal rates are measured at the wellhead; the difference between these two rates is the formation injection rate.To validate and improve this technique, we used a laboratory model mimicking a multi-layer formation, already available at LMS. We also made use of in-situ tests performed on an ultra-low permeable cap rock above an underground gas storage reservoir. In these tests, a viscous fluid contained in the open hole was displaced by a less-viscous fluid (a method called opening WTLog). The more permeable layers were correctly identified (Manivannan et al. 2017), but a quantitative estimation was challenging due to transient phenomena in the vicinity of the wellbore (near-wellbore zone). In addition, the investigation radius was small.These challenges are addressed by proposing a slightly modified test procedure and a new interpretation workflow. Laboratory tests with a modified test setup showed the advantages of the ‘closing’ method in which the well is filled with a less-viscous fluid at the start of the test. We also added a stabilization period before the injection of viscous fluid to minimize the transient effects; this period is also used to estimate the average permeability of the open hole and the effect of near-wellbore damage (skin).Then the test proper is performed (closing WTLog). The injection profile of the less-viscous fluid is computed from the wellhead flow rate history. A permeability profile is estimated from the injection profile. The permeability estimation considers a monophasic flow in each layer and the same skin value for all the formation layers. Major uncertainties in the permeability estimates are caused by formation pressures and heterogeneities in skin values; they are estimated using an analytical formula. We have verified on the laboratory setup that the estimated permeability profiles are well correlated to the permeabilities measured before the tests.An attempt was made to perform a WTLog in a 1750-m long wellbore opening in a salt formation. The first phase was successful and the average permeability was correctly assessed. However, this permeability was so small (4.0E-21 m² or 4 nD) that the gauges and the flowmeters were not accurate enough to allow a clear distinction between the permeabilities of the various parts of the open hole
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Mata, Mena Clemente. „Hydraulic behaviour of bentonite based mixtures in engineered barriers: The Backfill and Plug Test at the Äspö HRL (Sweden)“. Doctoral thesis, Universitat Politècnica de Catalunya, 2003. http://hdl.handle.net/10803/6234.
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In 1996 the Backfill and Plug Test Project started at the Äspö Hard Rock Laboratory (Sweden) managed by SKB (the Swedish Radioactive Waste Agency). The Backfill and Plug Test Project makes up an important part of SKB's research in order to store nuclear waste in a deep geological repository in a safe manner. ENRESA (the Spanish Radioactive Waste Agency) collaborates in this project with the Swedish companies SKB and Clay Technology in characterising the hydro-mechanical behaviour of the backfill material used to backfill a gallery.The backfill, obtained by mixing 30% of sodium bentonite MX-80 and 70% of crushed granite rock by weight, which maximum grain size was 20 mm, has been experimentally investigated. The experimental campaign took into account the salt water effects (up to 16 g/L) on its hydro-mechanical behaviour. Because of the bentonite content, its activity is quite large if compared with natural clayey soils.
Therefore, changes in the pore fluid chemistry influence the hydro-mechanical behaviour of this mixture. Due to the current application of the mixture, as candidate for sealing galleries in a future repository for nuclear waste, interest was focused on the variation of permeability related to variation of salt concentration in pore fluid.
Oedometer tests on specimens permeated with different salt water contents and water uptake tests permeated with different salt water contents were performed. Compaction tests with distilled and salt water were also performed. Osmotic suction was investigated on a different mixture of sodium bentonite and sand keeping the same weight ratio. Crushed granite was substituted by sand in order to use transistor psychrometers were used in this determination.
The experimental study of the mixture included the design and calibration of a new mini-piezometer which allows performing constant and variable head tests in saturated clayey soils. Some numerical tools were also developed to analyse pulse tests performed in laboratory and in situ (tests performed in late March of 2003 in the ZEDEX gallery in the ÄHRL full-scale laboratory). Different methods (analytical, semi-analytical and numerical) were used to analyse the pulse tests performed in laboratory and in situ.
Finally, the thesis focused on using a new finite element simulator, which solves thermo-hydro-mechanical-chemical (THMC) problems in a fully coupled way (Guimarães, 2002), to simulate the saturation process of a barrier for nuclear waste made up with this mixture. Interest was mainly focused on simulating the influence on the mixture hydraulic behaviour when salt concentration in pore fluid changed. A simple geochemical model, which took into account the ion exchange reaction between of Na+ and Ca2+, was considered. An empirical law of permeability variation with pore fluid salt concentration, obtained from the experimental information, was implemented in the finite element code. Effects of mixture molecular diffusion were also investigated, pointing out the importance of this parameter when transport of solutes in porous media is solved. Total suction was computed as the sum of matric suction and osmotic suction.
Osmotic suction was calculated by obtaining salt concentrations and by using the Van't Hoff equation. In this way, osmotic suction was not assumed constant as it is usually considered in engineering practice.
This thesis has contributed to the characterisation of a material, which is difficult to investigate, and it has provided with accurate information of the backfill permeability, one of the key parameters when designing a nuclear waste repository.
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Czownicka, Marta [Verfasser]. „Determination of active matrix metalloproteinase 8 (aMMP-8) levels in the gingival crevicular fluid as a diagnostic test during periodontal maintenance therapy / Marta Czownicka“. Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2016. http://d-nb.info/1119803012/34.
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