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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.
151

Software pro analýzu dálkového odečtu měřicích zařízení / Software for the analysis of the remote-reading of the meters

Přívětivý, Radek January 2015 (has links)
There are describes the principles of remote meter reading in the home and components of smart grids for reading these meters in the first part of master’s thesis. The next part of the thesis contains description of standard Wireless M-Bus and ZigBee. The next chapter is description of the circuit Realtek RTL2832U, which is part of the selected tuner. Another part is devoted to basic description of modulation focusing on the angle modulation – FM, FSK. In the final part is a detailed description of the received signal. AES encryption and created software.
152

A HIGHLY PRECISE AND LINEAR IC FOR HEAT PULSE BASED THERMAL BIDIRECTIONAL MASS FLOW SENSOR

Radadia, Jasmin Dhirajlal January 2010 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / In this work we have designed and simulated a thermal bi-directional integrated circuit mass flow sensor. The approach used here was an extension to the gas flow model given by Mayer and Lechner. The design features high precision response received from analog integrated circuits. A computational fluid dynamic (CFD) model was designed for simulations with air and water Using COMSOL Multiphysics. Established mathematical models for the heat flow equations including CFD parameters were used within COMSOL simulation(COMSOL Multiphysics, Sweden). Heat pulses of 55 °C for a period of nearly 120 seconds and 50% duty cycles were applied as thermal sources to the flowstream. The boundary conditions of the heat equations at the solid (heating element) fluid interface were set up in the software for the thermal response. The hardware design included one heating element and two sensing elements to detect the bi-directional mass flow. Platinum sensors were used due to their linear characteristics within 0 ºC to 100 ºC range, and their high temperature coefficient(0.00385 Ω/Ω/ºC). Polyimide thinfilm heater was used as the heating element due to its high throughput and good thermal efficiency. Two bridge circuits were used to sense the temperature distribution in the vicinity of the sensing elements. Three high precision instrumentation low power amplifiers with offset voltage ~2.5μV (50μV max) were used for bridge signal amplification and the difference circuit. The difference circuit was used to indicate the flow direction. A LM555 timer chip was utilized to provide the heat pulse period. Simulation and experimental measurements for heat pulses with different amplitude (temperature) were in good agreement. Also, the sensitivity of the flow sensor was observed to remain unaffected with the change in the duty cycle of the heat operation mode.
153

Feasibility study of Magnetic Flow Meters for Molten Salt Reactors

Nilsson, Sebastian January 2020 (has links)
This thesis investigates the possibility of using magnetic flow meters to measure the flowrate of molten salts in Seaborg Technologies Compact Molten Salt Reactor (CMSR).There is a need to accurately measure the flow rate in salt circulation systems to ensureproper operation of the entire facility. The requirements and criteria for the operationof a magnetic flow meter are studied, from which a model is constructed in COMSOLMultiphysics. The flow meter characteristics are analysed in COMSOL by performingsteady-state magnetohydrodynamic (MHD) simulations and by doing a sensitivity anal-ysis of the velocity field and the magnetic field strength. The induced electric potentialdifference in the flow meter when the reactor is at a maximum designed thermal power isin the range of 65 mV when using a normal inlet flow profile. The effect of the velocityfield is studied for two velocity profiles, and it indicates that the velocity profile alters theinduced potential difference even though the mass flowrate is the same. The magneticfield strength increases the electric potential difference when it is increasing, which isaccording to theory. The results indicate that magnetic flow meters are a viable optionfor Seaborg’s CMSR. However, further analysis is needed regarding the materials usedto ensure proper operation of the flow meter.
154

A context based data sanity checking algorithm and its implementation

Lahouar, Saher 01 February 2006 (has links)
In this dissertation, we present a cost-effective, neural network-based technique for data sanity checking and small system parameter monitoring which utilizes the contextual information in which data is collected to avoid the need for multiple metering. Multiple metering is not always a feasible nor an optimal solution to the problem. In an environment where it is necessary to monitor a large number of different physical variables, the mere installation and maintenance of multiple metering equipment can prove to be very costly. Moreover, multiple measurements of the same quantity result in a phenomenon known as data explosion. Context-based sensoyvalidation is achieved through cross sensor redundancy, which is not to be confused with metering redundancy. Neural networks are used to model the relationships among the various parameters and to provide context-based estimates which help in identifying sensor (versus system) malfunction. Slow tracking of the relationships among the parameters as they change over time is made possible through on-line training of the neural networks on the most recent data. This helps to account for the dependency of the relationships among system parameters on the range of external variables such as ambient temperature. A prototypical system titled DASANEX is implemented to illustrate the validity of the technique. The system is used to monitor and filter real-time transformer and ambient temperature data. A proof-of-concept is established using field data from the city of Martinsville Electric Department. Results prove the superior ability of the technique to identify sensor malfunction and to provide real-time adequate replacement values during short downtimes of the sensors even when some sensor data are missing or contaminated. / Ph. D.
155

Design of a data acquisition system to control and monitor a velocity probe in a fluid flow field

Herwig, Nancy Lou January 1982 (has links)
A data acquisition system to control the position of a velocity probe, and to acquire digital voltages as an indication of fluid velocity is presented. This system replaces a similar manually operated traverse system, it relieves the operator of control and acquisition tasks, while providing a more consistent and systematic approach to the acquisition process. The design includes the TRS-80 microcomputer, with external interfacing accomplished using the STD-based bus design. / Master of Science
156

Multicomponent continuous flow kinetic analysis

Hooley, David J. January 1981 (has links)
An instrumentation system for Multicomponent Continuous Flow Kinetic Analysis has been designed and constructed. Evaluation of the system shows that it is useful for performing dilutions, flow injection analysis and continuous flow kinetics with relative standard deviations of less than 10 percent. Modern electronic technology was used to construct a flow controller which was able to regulate the flow of a conducting liquid to ± 0.1 ml/min at flow rates of 2 to 10 ml/min. An inexpensive Light Emitting Diode colorimeter was able to detect KMnO₄ linearly at concentrations of 10 to 600 μm, with better than 1 percent relative standard deviation at the higher concentrations. Several concepts of hardware-software and software-operator interaction were introduced and developed. The multiprogrammed Fourth Programming System provided the instrument with much more capability and ease of use than might have been expected otherwise. The reaction of KMnO₄ with KI was employed as a single component continuous flow test reaction. Rate constants were in good agreement with literature values obtained by stopped flow methods. The ligand exchange reaction between metal-Zincon complexes and CyDTA, using zinc and mercury, demonstrated the feasibility of the instrument for multicomponent continuous flow kinetic analysis. The implementation of suggested instrumental improvements should extend the range of usable reaction rates and improve the accuracy of the determinations. The flowmeter and flow controller are potential alternatives to the relatively expensive pumps used for flow injection analysis. Evaluation of the instrument’s operation in flow injection mode indicates that it is useful as a convenient continuous flow kinetic detector for flow injection analysis and for testing developments in flow injection theory. / Ph. D.
157

Issues of trust, fairness and efficacy: a qualitative study of information provision for newly metered households in England.

Knamiller, C., Sharp, Liz January 2009 (has links)
No / There is widespread agreement among agencies governing UK water management that more extensive domestic water metering combined with additional measures will deliver a more efficient domestic water usage. This paper argues that qualitative research is needed to select and hone additional measures. According to theory, cooperation to reduce water use is more likely if people: a) believe in the necessity to reduce use; b) feel costs are fairly shared; and c) believe their actions can affect the situation. The case study of Lydd, Kent, is presented. Lydd is the first location in which compulsory water metering has been imposed in the UK. Qualitative information was collected to inform the communication strategies being implemented by the water supply company. The investigation found that none of the three factors predicted by theory were completely present. The paper concludes by providing some recommendations for improving the water company's communications strategy for encouraging a reduction in domestic water use. The key role of qualitative information in assisting in the targeting and design of water demand management programmes is highlighted.
158

Performance of a symmetrical converging-diverging tube differential pressure flow meter

Ilunga, Luc Mwamba January 2014 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Civil Engineering in the Faculty of Engineering at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2014 / The current problems of orifice, nozzle and Venturi flow meters are that they are limited to turbulent flow and the permanent pressure drop produced in the pipeline. To improve these inadequacies, converging-diverging (C-D) tubes were manufactured, consisting of symmetrical converging and diverging cones, where the throat is the annular section between the two cones, with various angles and diameter ratios to improve the permanent pressure loss and flow measurement range. The objective of this study was firstly to evaluate the permanent pressure loss, secondly to determine the discharge coefficient values for various C-D tubes and compare them with the existing differential pressure flow meter using Newtonian and non-Newtonian fluids, and finally to assess the performance of these differential pressure flow meters. The tests were conducted on the multipurpose test rig in the slurry laboratory at the Cape Peninsula University of Technology. Newtonian and non-Newtonian fluids were used to conduct experiments in five different C-D tube flow meters with diameter ratios (β) of 0.5, 0.6 and 0.7, and with angles of the wall to the axis of the tube (θ) of 15°, 30° and 45°. The results for each test are presented firstly in the form of static pressure at different flow rates. It was observed that the permanent pressure loss decreases with the flow rate and the length of the C-D tube. Secondly, the results are presented in terms of discharge coefficient versus Reynolds number. It was found that the Cd values at 15° drop earlier than at 30° and 45°; when viscous forces become predominant, the Cd increases with increasing beta ratio. The Cd was found to be independent of the Reynolds number for Re>2000 and also a function of angle and beta ratio. Preamble Performance of a symmetrical converging-diverging tube differential pressure flow meter Finally, the error analyses of discharge coefficients were assessed to determine the performance criteria. The standard variation was found to increase when the Reynolds number decreases. The average discharge coefficient values and their uncertainties were determined to select the most promising C-D tube geometry. An average Cd of 0.96, with an uncertainty of ±0.5 % for a range of Reynolds numbers greater than 2,000 was found. The comparison between C-D tubes 0.6(15-15) and classical Venturi flow meters reveals that C-D 0.6(15-15) performs well in turbulent range and shows only a slight inaccuracy in laminar. This thesis provides a simple geometrical differential pressure flow meter with a constant Cd value over a Reynolds number range of 2000 to 150 000.
159

From Passive to Active Electric Distribution Networks

Campillo, Javier January 2016 (has links)
Large penetration of distributed generation from variable renewable energy sources, increased consumption flexibility on the demand side and the electrification of transportation pose great challenges to existing and future electric distribution networks. This thesis studies the roles of several actors involved in electric distribution systems through electricity consumption data analysis and simulation models. Results show that real-time electricity pricing adoption in the residential sector offers economic benefits for end consumers. This occurs even without the adoption of demand-side management strategies, while real-time pricing also brings new opportunities for increasing consumption flexibility. This flexibility will play a critical role in the electrification of transportation, where scheduled charging will be required to allow large penetration of EVs without compromising the network's reliability and to minimize upgrades on the existing grid. All these issues add significant complexity to the existing infrastructure and conventional passive components are no longer sufficient to guarantee safe and reliable network operation. Active distribution networks are therefore required, and consequently robust and flexible modelling and simulation computational tools are needed for their optimal design and control. The modelling approach presented in this thesis offers a viable solution by using an equation-based object-oriented language that allows developing open source network component models that can be shared and used unambiguously across different simulation environments.
160

Probe characterisation, design and evaluation for the real-time quality Indication of milk

Van der Westhuyzen, Petrus Johannes 12 1900 (has links)
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006. / In order to rapidly detect, monitor and predict changes in milk as it ferments, sensors would need to be designed specifically for milk. To this end, invasive surgical stainless steel probes were investigated and the probe impedances were characterised according to measurements made in various saline concentrations. Based on these findings, specific probes were designed that were robust and easy to use in milk. To measure multiple probe sensors continuously and accurately, an automatic measurement device was designed and manufactured. The device was self-sustaining, portable and calculated and stored all probe impedance data internally, allowing experimental runs to take place in controlled laboratory environments. The probes designed in this thesis were consequently tested in various milk fermentation experiments and it was found that surgical stainless steel probes were effective at detecting and monitoring fermentation changes. The probe impedance changes also lead the pH changes in milk, giving it a predictive element. The probe sensor studies provided enough data so that studies could be done into potential non-invasive sensors. Therefore, capacitive sensors were investigated and a fringe field capacitor was presented as a potential non-invasive milk fermentation sensor.

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