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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

The system optimization of the nuclear magnetic resonance flowmeter

McCormick, William Sands, January 1967 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1967. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 205-206).
32

Non-Newtonian fluid flow measurement using sharp crested notches

Khahledi, Morakane Charlotte January 2014 (has links)
Master of Technology: Civil Engineering In the Faculty of Engineering At the Cape Peninsula University of Technology 2014 / Notches, particularly rectangular and V shaped are the cheapest and most common devices used to measure the flow rate of water in open channels. However, they have not been used to measure the flow rate of non-Newtonian fluids. These viscous fluids behave differently from water. It is difficult to predict the flow rate of such fluids during transportation in open channels due to their complex viscous properties. The aim of this work was to explore the possibility of extending the application of especially rectangular and V-shaped notches to non-Newtonian fluids. The tests reported in this document were carried out in the Flow Process and Rheology Centre laboratory. Notches fitted to the entrance of a 10 m flume and an in-line tube viscometer were calibrated using water. The in-line tube viscometer with 13 and 28 mm diameter tubes was used to determine the fluid rheology. Flow depth was determined using digital depth gauges and flow rate measurements using magnetic flow meters. Three different non-Newtonian fluids, namely, aqueous solutions of Carboxymethyl Cellulose (CMC) and water-based suspensions of kaolin and bentonite were used as model non-Newtonian test fluids. From these the coefficient of discharge (Cd) values and appropriate non-Newtonian Reynolds numbers for each fluid and concentration were calculated. The experimental values of the coefficient of discharge (Cd) were plotted against three different definitions of the Reynolds number. Under laminar flow conditions, the discharge coefficient exhibited a typical dependence on the Reynolds number with slopes of ~0.43-0.44 for rectangular and V notches respectively. The discharge coefficient was nearly constant in the turbulent flow regime. Single composite power-law functions were used to correlate the Cd-Re relationship for each of the two notch shapes used. Using these correlations, the Cd values could be predicted to within ±5% for the rectangular and V notches. This is the first time that such a prediction has been done for a range of non-Newtonian fluids through sharp crested notches. The research will benefit the mining and food processing industries where high concentrations of non-Newtonian fluids are transported to either disposal sites or during processing.
33

Kalman filter and its application to flow forecasting

Ngan, Patricia January 1985 (has links)
The Kalman Filter has been applied to many fields of hydrology, particularly in the area of flood forecasting. This recursive estimation technique is based on a state-space approach which combines model description of a process with data information, and accounts for uncertainties in a hydrologic system. This thesis deals with applications of the Kalman Filter to ARMAX models in the context of streamflow prediction. Implementation of the Kalman Filter requires specification of the noise covariances (Q, R) and initial conditions of the state vector (x₀, P₀). Difficulties arise in streamflow applications because these quantities are often not known. Forecasting performance of the Kalman Filter is examined using synthetic flow data, generated with chosen values for the initial state vector and the noise covariances. An ARMAX model is cast into state-space form with the coefficients as the state vector. Sensitivity of the flow forecasts to specification of x₀, P₀, Q, R, (which may be different from the generation values) is examined. The filter's forecasting performance is mainly affected by the combined specification of Q and R. When both noise covariances are unknown, they should be specified relatively large in order to achieve a reasonable forecasting performance. Specififying Q too small and R too large should be avoided as it results in poor flow forecasts. The filter's performance is also examined using actual flow data from a large river, whose behavior changes slowly with time. Three simple ARMAX models are used for this investigation. Although there are different ways of writing the ARMAX model in state-space form, it is found that the best forecasting scheme is to model the ARMAX coefficients as the state vector. Under this formulation, the Kalman Filter is used to give recursive estimates of the coefficients. Hence flow predictions can be revised at each time step with the latest state estimate. This formulation also has the feature that initial values of the ARMAX coefficients need not be known accurately. The noise variances of each of the three models are estimated by the method of maximum likelihood, whereby the likelihood function is evaluated in terms of the innovations. Analyses of flow data for the stations considered in this thesis, indicate that the variance of the measurement error is proportional to the square of the flow. In practice, flow predictions several time steps in advance are often required. For autoregressive processes, this involves unknown elements in the system matrix H of the Kalman model. The Kalman algorithm underestimates the variance of the forecast error if H and x are both unknown. For the AR(1) model, a general expression for the mean square error of the forecast is developed. It is shown that the formula reduces to the Kalman equation for the case where the system matrix is known. The importance of this formula is realized in forecasting situations where management decisions depend on the reliability of flow predictions, reflected by their mean square errors. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate
34

Mechano-Magnetic Telemetry For Urban Infrastructure Monitoring

Orfeo, Daniel Jerome 01 January 2018 (has links)
Many cities seek utilities monitoring with centrally managed Internet of Things (IoT) systems. This requires the development of numerous reliable low-cost wireless sensors, such as water temperature and flow meters, that can transmit information from subterranean pipes to surface-mounted receivers. Traditional radio communication systems are either unable to penetrate through multiple feet of earthen and manmade material, or have impractically large energy requirements which necessitate either frequent replacement of batteries, or a complex (and expensive) built-in energy harvesting system. Magnetic signaling systems do not suffer from this drawback: low-frequency electromagnetic waves have been shown to penetrate well through several feet of earth and water. In the past, these signals were too weak for practical use; however, this has changed with the recent proliferation of high-sensitivity magnetometers and compact rare-earth magnets. A permanent magnet can be either rotated or vibrated to create an oscillating magnetic field. Utilizing this phenomenon, two types of magnetic transmitter are investigated in this study: one which uses a propeller to directly rotate a diametrically magnetized neodymium magnet; and a second in which a permanent magnet is oscillated back-and-forth across a novel soft-magnet Y-stator, which projects a switching magnetic field. In principle, these oscillating magnetic fields can be used for communication from subterranean infrastructure sensors—such as flow meters and leak detection devices—to an aboveground long range (LoRa) radio-networked Arduino receiver equipped with a magnetometer. Simulation software models the oscillating electromagnetic fields produced by the Y-stator configuration. Laboratory performance and field tests establish the capability of two IoT-linked leak-detection sensors that use magnetic telemetry. Remote datalogging demonstrates the viability of integrating many sensors and surface receivers into a single LoRa wireless IoT network.
35

Comparison of Selected Differential Producing, Ultrasonic, and Magnetic Flow Meters

Prettyman, Johnny B. 01 May 2014 (has links)
Flow meters are used to measure flow accurately. There are many different flow meters and it is necessary to know which will function best for specific situations. A wide variety of flow meters were selected for the study to assist in showing that each flow meter has its tradeoffs. The selected meters include: three types of Venturi meters, a wedge meter, a V-cone meter, an electromagnetic flow meter, and an ultrasonic flow meter. The characteristics researched in this study are discharge coefficient (Cd) over a range of Reynolds numbers (Re), head loss across each flow meter, life, and cost of meter. Each meter was tested over a wide range of Re to find the corresponding Cd and head loss. The life and cost of each meter were researched and estimated based on the flow meter companies and local distributor’s findings. With the findings, the tradeoffs are illustrated and will assist buyers in selecting a flow meter that will best fit their needs. While there are more flow meters available than was tested, the current study can direct buyers in a correct process of selecting meters for all situations.
36

Experimental study of thermosiphon performance

Sivanagere, Sumeeth S. January 2002 (has links)
Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains vii, 66 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 29).
37

Learning and applying material-based sensing lessons from nature

McConney, Michael Edward. January 2009 (has links)
Thesis (Ph.D)--Polymer, Textile and Fiber Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Tsukruk, Vladimir; Committee Member: Shofner, Meisha; Committee Member: Srinivasarao, Mohan; Committee Member: Thio, Yonathan; Committee Member: Weissburg, Marc. Part of the SMARTech Electronic Thesis and Dissertation Collection.
38

Low differential pressure and multiphase flow measurements by means of differential pressure devices

Ruiz, Justo Hernandez. January 1900 (has links)
Thesis (Ph.D.)--Texas A & M University, 2004. / Title from caption (viewed on Feb. 8, 2008). Title from document title page. Includes bibliographical references. Available in PDF format via the World Wide Web.
39

Design of a clamp-on ultrasonic flow meter for wet gas pipelines

Vedapuri, Damodaran. January 2001 (has links)
Thesis (Ph. D.)--Ohio University, June, 2001. / Title from PDF t.p. Includes bibliographical references (leaves 191-193).
40

Development of multiphase flow metering set-up utilizing coriolis meters

Al-Taweel, Ahmed Baqer. January 1997 (has links) (PDF)
Thesis (M.S.)--King Fahd University of Petroleum and Minerals, 1997 / Title from document title page. Includes bibliographical references. Available in PDF format via the World Wide Web.

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