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1
Yu, Tzu-Yang (Tzu-Yang Young) 1973. "Behavior of a coupled arch system". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/84825.
Testo completo
2
Leung, Wing K. (Wing Keung). "Development of a computer-coupled fermentation system". Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59598.
Testo completoAbstract (sommario):
A computer-coupled fermentation system has been developed for advanced research in fermentation technology.Application software programs were developed as concurrent task programs to perform data acquisition, process monitoring and feed stream manipulation.
Another software program was also developed to support the application programs in a concurrent programming environment. This program supports generalized menu-driven operator interface and is application independent. The menu is reconfigurable by utility programs. Its well-defined parameter passing and input/output protocols enable the application software modules to be reused in different applications in a convenient way.
A chemical solutions delivery system was also developed to some extent to allow fermentations to be studied in well controlled, unconventional modes of operation based on fed-batch or continuous-flow culture systems.
Performance of the system components and new software were tested in operation simulations and one batch and three fed batch fermentations employing the acetone-butanol-ethanol process with Clostridium acetobutylicum.
3
Heun, Oliver. "Spin-restricted Coupled-Cluster-Theorie für offenschalige Zustände". [S.l. : s.n.], 2002. http://ArchiMeD.uni-mainz.de/pub/2002/0166/diss.pdf.
Testo completo
4
O'Brien, Kathleen. "Inductively coupled radio frequency power transmission system for wireless systems and devices /". Aachen : Shaker, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=015959229&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
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5
Bacardit, Peñarroya Jordi. "Coupled photochemical-biological system to treat biorecalcitrant wastewaters". Doctoral thesis, Universitat de Barcelona, 2007. http://hdl.handle.net/10803/1533.
Testo completoAbstract (sommario):
Advanced Oxidation Processes (AOPs) are suitable for achieving the complete mineralization of organic pollutants in wastewaters, since they are based on the generation of a powerful non-selective chemical oxidant. A major drawback of AOPs is that they involve high operating costs if high levels of mineralization are endeavoured. Integration of an AOP with a biological treatment has demonstrated to be a suitable alternative, since it combines the capacity of the AOP, in this case Photo-Fenton, to enhance biodegradability, with a biological treatment such as a Sequencing Batch Biofilter Reactor (SBBR), which operating costs are lower.Photo-Fenton (Ph-F) process is carried out by irradiating the system with ultraviolet (UV) and/or visible (Vis) light. In Fenton processes, by combination of hydrogen peroxide (H2O2) as a reagent and iron ions (Fe2+ for example) as catalyst in acid medium, highly oxidant species are generated.
According to the results, most of the studied parameters may be written as a function of [H2O2]0, which means that temperature and [Fe2+]0 do not affect significantly the results. Moreover, a subsequent scale-up of the process shows that degradation follow very similar tendencies and shows similar results.
It has been observed that the efficiency of oxidation follows a tendency directly related to the amount of H2O2 applied. An innovative description of the process is their modelling regarding the evolution of COD and BOD5 over the oxidation process or depending on the amount of H2O2 applied. The models show good fitting properties, and they appear to be a good basis for more precise modelling of the system.
Regarding the integration of both processes, the best operating conditions consists of first treating the solution by Ph-F with 500 mg.L-1 of [H2O2]0 and 10 mg.L-1 of [Fe2+]0 at 27 ºC. The resulting product is then treated in the SBBR for 8 hours of time. More than 90 % of mineralization is achieved. The bioreactor show high resistance when is exposed to toxic shock load. Concerning control possibilities, monitoring the Oxygen Uptake Rate (OUR) by in-situ respirometry is suggested to be a good parameter, since it is a direct measurement of bacterial activity.
6
Girija, Sasidharan Pillai Harish. "Analysis of coupled body mooring and fender system". Texas A&M University, 2005. http://hdl.handle.net/1969.1/2608.
Testo completoAbstract (sommario):
The hydrodynamic excitation and response behavior of multi-body systems with
varying degrees of coupling presents many challenges for designers of offshore
structures. In this study, attention is focused upon the analysis and interpretation of
experimental data obtained for an unmanned deepwater mini-Tension Leg Platform
(mini-TLP) coupled to a tender barge. Each body has its own mooring system and the
bodies are connected by two breast lines extending from central points on the mini-TLP
to central points on the bow and stern of the tender barge. A fender system is located
between the two platforms. Thus the two floating bodies are constrained to move
together in surge and yaw while they are free to move independently in heave, roll and
pitch with some limitations on sway.
The data of the individual records are characterized using statistical moments,
including skewness and kurtosis, to examine the degree of non-Gaussian behavior.
Correlation analysis and cross spectral analysis are used to investigate the relationships
between selected measurements such as the motion of each vessel, tensions in the
mooring lines and tendons and the forces on the fenders. The analysis shows that the
coupling effects reduce the mooring line and tendon tensions significantly and that the
motions of the two vessels influence the line tensions and fender forces. The data
distribution patterns followed by the parameters and the corresponding extreme values
are also investigated.
7
Gentine, Pierre. "Spectral behavior of the coupled land-atmosphere system". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/61243.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, February 2010.Cataloged from PDF version of thesis.
Includes bibliographical references.
The main objective of this thesis is to understand the daily cycle of the energy coupling between the land and the atmosphere in response to a forcing of incoming radiation at their common boundary, the land surface. This is of fundamental importance as that the initial/ boundary conditions of the land-surface state variables (e.g. soil moisture, soil temperature) exert strong control at various temporal scales on hydrologic, climatic and weather related processes. Hence diagnosing these state variables is crucial for extreme hydrological forecasting (flood/ drought), agronomic crop management as well as weather and climatic forecasts. Consequently in this thesis, the daily behavior of a simple land-atmosphere model is examined. A conceptual and linearized land-atmosphere model is first introduced and its response to a daily input of incoming radiation at the land surface is investigated. The solution of the different state and fluxes in the Atmospheric Boundary Layer (ABL) and in the soil are expressed as temporal Fourier series with vertically dependent coefficients. These coefficients highlight the impact of both the surface parameters and the frequency of the radiation on the heat propagation in the ABL and in the soil. The simplified model is shown to compare well with field measurements thus accounting for the main emergent behaviors of the system. The first chapter of the thesis describes the theoretical background of the equations governing the evolution of temperature and humidity in the ABL and in the soil. In the second chapter, the pioneering work of Lettau (1951), which inspired our approach is summarized. In his work Lettau studied the response of a simplified linearized land-atmosphere model to a sinusoidal net radiation forcing at the land surface. The third chapter of the thesis describes the SUDMED project, which took place in Morocco in 2003. During this project a wheat field was fully instrumented with continuous measurements of soil moisture, radiative fluxes, turbulent heat fluxes and soil heat flux. This site will be taken as a reference for model comparison. The fourth chapter of the thesis presents the three studies with distinctive goals. In these studies our linearized land-atmosphere model is first introduced. Then the propagation of the land-surface diurnal heating is presented and the model is compared to observations from the SUDMED project. Finally the repercussion of a land-surface energy budget error noise is investigated. Finally in the last chapter of the thesis we discuss possible evolution and improvements of the analytical coupled model presented in this thesis. In particular, it is emphasized that the non-linearity of the the boundary-layer height is of great importance for the predictability of the ABL state.
by Pierre Gentine.
Ph.D.
8
Alghamdi, Jamal Khaled. "CFD Simulation Methodology for Ground-Coupled Ventilation System". Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/35736.
Testo completoAbstract (sommario):
In the past two decades, a growing interest in alternative energy resources as a
replacement to the non-renewable resources used now days. These alternatives include
geothermal energy which can be used to generate power and reduce the demands on
energy used to heat and cool buildings. Ground-coupled ventilation system is one of the
many applications of the geothermal energy that have a lot of attention in the early 80â s
and 90â s but all designs of the system where based on single case situations. On the other
hand, computational fluid dynamics tools are used to simulate heat and fluid flow in any
real life situation. They start to develop rapidly with the fast development of computers
and processors. These tools provide a great opportunity to simulate and predict the
outcome of most problems with minimum loss and better way to develop new designs.
By using these CFD tools in GCV systems designing procedure, energy can be conserved
and designs going to be improved.
The main objective of this study is to find and develop a CFD modeling strategy
for GCV systems. To accomplish this objective, a case study must be selected, a proper
CFD tool chosen, modeling and meshing method determined, and finally running
simulations and analyzing results. All factors that affect the performance of GCV should
be taken under consideration in that process such as soil, backfill, and pipes thermal
properties. Multiple methods of simulation were proposed and compared to determine the
best modeling approach.Master of Science
9
Alfadil, Mohammad Omar. "Design Tool for a Ground-Coupled Ventilation System". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/100604.
Testo completoAbstract (sommario):
Ground-coupled ventilation (GCV) is a system that exchanges heat with the soil. Because ground temperatures are relatively higher during the cold season and lower during the hot season, the system takes advantage of this natural phenomenon. This research focused on designing a ground-coupled ventilation system evaluation tool of many factors that affect system performance. The tool predicts the performance of GCV system design based on the GCV system design parameters including the location of the system, pipe length, pipe depth, pipe diameter, soil type, number of pipes, volume flow rate, and bypass system. The tool uses regression equations created from many GCV system design simulation data using Autodesk Computational Fluid Dynamics software. As a result, this tool helps users choose the most suitable GCV system design by comparing multiple GCV systems' design performances and allows them to save time, money, and effort.Doctor of Philosophy
10
Toffin, Eric. "Active control of a coupled plate-cylinder system". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06162009-063337/.
Testo completo
11
Wu, Wenzhi (Winston). "An Internet-coupled Real—Time Air Monitoring System". Thesis, The University of Sydney, 2005. https://hdl.handle.net/2123/28172.
Testo completoAbstract (sommario):
This thesis describes an industrial odour monitoring system to monitor environmental odours from a meat processing plant. The author designed and implemented the monitoring hardware and a data network logging system which operated on site for three to four months. The performance of this system proves that the e-nose designed for this project is robust in industrial conditions and will provide a low-cost and adequately sensitive system that can run in real-time, and thereby meet the need for industry to comply with the growing demands by regulatory bodies for clean environmental air.
12
Ganbat, Atarsaikhan. "Reducibility of steady-state bifurcations in coupled cell systems". 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188451.
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Payne, R. R. "The design of a tightly coupled multiple microprocessor system". Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.384032.
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14
Frölicher, Thomas L. "Ensemble modeling of the coupled carbon cycle-climate system /". [S.l.] : [s.n.], 2009. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Piechowski, Miroslaw. "A ground coupled heat pump system with energy storage /". Connect to thesis, 1996. http://eprints.unimelb.edu.au/archive/00000724.
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Miller, Mark W. "Heat transfer in a coupled impingement-effusion cooling system". Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4807.
Testo completoAbstract (sommario):
The efficiency of air-breathing gas turbine engines improves as the combustion temperature increases. Therefore, modern gas turbines operate at temperatures greater than the melting temperature of hot-gas-path components, and cooling must be introduced in order to maintain mechanical integrity of those components. Two highly effective techniques used in modern designs for this purpose are impingement cooling and use of coolant film on hot-gas-path surface introduced through discrete film or effusion holes. In this study, these two mechanisms are coupled into a single prototype cooling system. The heat transfer capability of this system is experimentally determined for a variety of different geometries and coolant flow rates. This study utilizes Temperature Sensitive Paint (TSP) in order to measure temperature distribution over a surface, which allowed for local impingement Nusselt number, film cooling effectiveness, and film cooling heat transfer enhancement profiles to be obtained. In addition to providing quantitative heat transfer data, this method allowed for qualitative investigation of the flow behavior near the test surface. Impinging jet-to-target-plate spacing was varied over a large range, including several tall impingement scenarios outside the published limits. Additionally, both in-line and staggered effusion arrangements were studied, and results for normal injection were compared to full coverage film cooling with inclined- and compound-angle injection. Effects of impingement and effusion cooling were combined to determine the overall cooling effectiveness of the system. It is shown that low impingement heights produce the highest Nusselt number, and that large jet-to-jet spacing reduces coolant flow rate while maintaining moderate to high heat transfer rates. Staggered effusion configurations exhibit superior performance to in-line configurations, as jet interference is reduced and surface area coverage is improved. Coolant to mainstream flow mass flux ratios greater than unity result in jet blow-off and reduced effectiveness. The convective heat transfer coefficient on the film cooled surface is higher than a similar surface without coolant injection due to the generation of turbulence associated with jet-cross flow interaction.ID: 030646180; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; .; Thesis (M.S.M.E.)--University of Central Florida, 2011.; Includes bibliographical references (p. 171-176).
M.S.M.E.
Masters
Mechanical and Aerospace Engineering
Engineering and Computer Science
Mechanical Engineering; Thermo-Fluids Track
17
Brama, Elisabeth. "Ion trap cavity system for strongly coupled cavity-QED". Thesis, University of Sussex, 2013. http://sro.sussex.ac.uk/id/eprint/45218/.
Testo completoAbstract (sommario):
The combination of an ion trap with a high finesse optical cavity is an ideal system for the investigation of strong coupling cavity quantum electrodynamics, and allows the observation of a number of interesting quantum phenomena. To achieve the small mode volumes required without impairing the ion trapping small traps with a short ion electrode distance are needed. Two microscopic linear rf ion traps have been developed and built to accommodate experimental cavities of lengths of several 100 microns. The first trap design, the 'sandwich' trap, was successfully used to trap 40Ca+ - ions for several hours. It was characterised extensively including a measurement of the heating rates of the ions in the trap. Spectroscopy measurements of the cooling transition, as well as the two repumping transitions were carried out. The second trap design, the 'alumina' trap, also successfully trapped 40Ca+ - ions, and a full characterisation of this trap was made. The experimental cavity was installed at a preliminary cavity length distance of 3.7 mm. The cavity characteristics were examined. Finally the trapped ions were overlapped with the cavity mode by adjusting the trap minimum position along the trap axis via dc voltages and the vertical position of the cavity. To progress further a locking scheme for the cavity length as well as a single - photon detection setup are necessary. To achieve strong coupling a reduction of the cavity length will have to be made.
18
Huang, Shell Ying. "A functional processor system model on loosely-coupled machines". Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/46348.
Testo completo
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Miu, Kevin Kar-Leung. "A low cost, DC-coupled active vibration isolation system". Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/46061.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.Includes bibliographical references (p. 303-306).
In this thesis, I designed and implemented an isolation system that interfaces with traditional air mounts for improved force disturbance rejection relative to passive optical tables.Force disturbance rejection and position alignment are two major functional requirements of vibration isolation systems. With conventional passive isolation systems, a tradeoff exists between improving force disturbance rejection maintaining ground vibration isolation. Commercial active isolators address such a tradeoff through the use of inertial sensors, but the AC-coupled nature of the sensors leads to an inconvenient low frequency response. By referencing a payload stiffly to a softly suspended proof mass, both of the aforementioned functional requirements can be resolved while maintaining ground disturbance isolation performance. Philips Applied Technologies originally developed the concept, named Advanced Isolation ModuleS (AIMS).The AIMS system uses a relative displacement measurement between a payload which is to be isolated from vibrations and a proof mass as feedback. The displacement sensor allows the inertial measurement to be DC-coupled. The objective of this research is to find a relatively low-cost approach for the AIMS concept.A 1-DOF active vibration isolation system based on closed loop control utilizing the DC-coupled inertial measurement as feedback was retrofitted onto an optical table. The coil of a commercial geophone was used as the proof mass, as the geophone provides a relatively inexpensive, low frequency suspension. Error budgeting was performed on the system to estimate and improve payload acceleration noise levels. The results yielded a system bandwidth of 30 Hz and a total system acceleration la value of approximately 1 mm/s².
by Kevin Kar-Leung Miu.
S.M.
20
Rosner, Devon (Devon J. ). "A high speed wearable system for body coupled communication". Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/100669.
Testo completoAbstract (sommario):
Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 83-84).
There are currently no ideal methods by which doctors can read bodily signals detected by implanted devices. Methods are either too high power for long-term implants, such as radio transmission, or pose health threats to the patient, such as connection ports piercing the skin. However, a novel method of transmitting and receiving electronic sensor data is emerging known as body coupled communication (BCC). This method of communication utilizes the inside of the body's low impedance at frequencies on the order of 100 MHz to send signals over that channel and receive the signals at another location on the body. It is also a lower power and more secure wireless option than radio transmission. This thesis presents a 3 Mbps wearable receiver and transmitter system for BCC that was developed from commercially available electrical components and a custom PCB. Both receiver and transmitter are on the same PCB. They share a digital FPGA system, but have separate analog signal conditioning sections on the board.
by Devon Rosner.
M. Eng.
21
Farneti, Riccardo. "Oceanic planetary waves in the coupled ocean-atmosphere system". Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/25139/.
Testo completoAbstract (sommario):
The propagation of planetary, or Rossby, waves is studied under the effects of different atmospheric couplings. First, analytical matchings are formulated in which a Rossby wave is coupled to different thermodynamical atmospheres, from a simple heat flux condition to the inclusion of an atmospheric energy balance model. The effects on the vertical structure and phase speed of the first modes are negligible. However, it is shown that for the latter case an unstable mode appears. This growing mode, of decadal period and growth rate, has no physical source of energy and therefore is a result of the oversimplified atmosphere employed. In fact, adding physics to the atmospheric model results in a gradual disappearance of the instability. The possibility of observing similar unphysical modes in climate studies, where oversimplified models are adopted, is raised. Next, a quasi-geostrophic coupled model is used in order to analyse the oceanic Rossby wave characteristics under the influence of a full atmosphere. The idealised eddy-resolving model consists of an ocean basin underneath a channel atmosphere, and different configurations for the oceanic component are used. The Rossby waves are observed to propagate faster than both the classical linear theory (unperturbed solution) and the phase speed estimates when the effect of the zonal mean flow is added (perturbed solution). Moreover, using statistical eigentechniques, a coupled Rossby wave is identified, bearing the characteristics of the coupled mode proposed by Goodman and Marshall (1999). It is argued that the atmospheric coupling is capable of adding an extra speed up to the wave; in fact, when the waves are simply forced, their propagation speed approaches the perturbed solution. The waves are observed to break into faster waves, as suggested by LaCasce and Pedlosky (2004), although their resistance to dissipation and instabilities processes is enhanced by the atmospheric coupling, which provides extra energy to the initial wave during its propagation. The development of a coupled Rossby wave is found to be possible in a basin of the dimensions of both the Pacific and the Atlantic ocean, and its characteristics and strength vary little when the tridimensional accuracy of the ocean is increased.
22
Lennox, Scott Evan. "Coupled Attitude And Orbital Control System Using Spacecraft Simulators". Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/10003.
Testo completoAbstract (sommario):
Translational and rotational motion are coupled for spacecraft performing formation flying missions. This motion is coupled because orbital control is dependent on the spacecraft attitude for vectored thrust. Formation flying spacecraft have a limited mass and volume for propulsion systems. We want to maximize the efficiency of the spacecraft, which leads to minimizing the error introduced by thrusting in the wrong direction. This thrust direction error leads to the need for a coupled attitude and orbital control strategy. In this thesis a coupled control system is developed using a nonlinear Lyapunov attitude controller and a nonlinear Lyapunov-based orbital controller. A nonlinear Lyapunov attitude controller is presented for a spacecraft with three-axis momentum wheel control. The nonlinear Lyapunov-based orbital controller is combined with a mean motion control strategy to provide a globally asymptotically stable controller. The attitude and orbit control laws are verified separately using numerical simulation, and then are integrated into a coupled control strategy. The coupled system simulations verify that the coupled control strategy is able to correct for an initial relative position error between two spacecraft.Master of Science
23
Graham, Stephen Thomas. "Continental river routing for fully coupled climate system models /". Full text (PDF) from UMI/Dissertation Abstracts International, 2000. http://wwwlib.umi.com/cr/utexas/fullcit?p3024456.
Testo completo
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Lyne, O. D. "Probability and analysis for a hyperbolic coupled PDE system". Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319202.
Testo completo
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Bano, Rakhshinda. "Coupled human-water interactions in formal-informal dynamics". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2023. https://ro.ecu.edu.au/theses/2697.
Testo completoAbstract (sommario):
Urban water supply systems in developing world are complex due to the involvement of numerous stakeholders, compounded by poor management, exacerbated by the impacts of population and economic growth as well as climate change. As a result, there is a need to comprehensively comprehend the complex interactions between humans and water, especially as formal-informal water supply dynamics continue to emerge. This understanding is crucial in informing policy decisions that support the advancement of sustainable urban water systems. Therefore, analysing the coevolving dynamics and feedbacks associated with water systems where formal and informal components coexist is essential.
To better comprehend the intricacies of human-water interactions in developing countries, an integrated System Dynamics (SD) model has been developed. This model employs both qualitative and quantitative systems modelling techniques. Causal Loop Diagrams (CLDs) are utilized to display the relationships and identify system behaviour patterns, which are also known as system archetypes. Meanwhile, stock and flow diagrams are used in Stella Architect to quantify interlinkages. To verify the model, expert consultations, re-evaluation of data from government and private research organizations, statistical data analysis, and mapping of land use and land cover change (LULC) are utilized.
The findings indicate that the coexistence of formal and informal water systems can give rise to common system patterns or archetypes that have implications for the future of urban water management. These archetypes include 'fixes that fail', 'shifting the burden', 'limits to growth/success', and 'growth and underinvestment'. Quantification of these interactions revealed a weak association between informal demand and lower formal tariff recovery rates, with household income playing a significant role. The financial balance of the formal water supply system (FWSS) seems to be less influenced by tariff recovery rates and more dependent on infrastructure condition.
The presence of informal water supply systems is observed to decrease the reliability of the overall system due to higher inflation rates, increased theft by informal suppliers, and lower informal supply capacity. The supply-demand gap is further exacerbated by seasonal water supply changes and competing agricultural demands, which could be addressed by improving agricultural efficiency. To achieve integrated urban water management, it is essential to understand the boundaries of the system and the interactions among its components, in order to make changes to the urban water balance.
To achieve our goal of providing a comprehensive and integrated approach to evaluating formal-informal water supply dynamics at the urban level, we aggregated our assessments at multiple levels, thereby minimizing heterogeneities such as differences among socio-economic groups in evaluating household demand, variations in non-domestic users such as commercial and industrial, types of informal suppliers, and water quantity and quality. This study primarily aims to provide a general overview of how formal and informal water supply systems at a broader level contribute to defining urban water supply reliability and how this reliability is impacted by other variables in the system over time.
26
O'Brien, Kathleen [Verfasser]. "Inductively Coupled Radio Frequency Power Transmission System for Wireless Systems and Devices / Kathleen O'Brien". Aachen : Shaker, 2007. http://d-nb.info/1166516717/34.
Testo completo
27
Whitesides, Benton W. "Interannual Zonal Variability of the Coupled Stratosphere-Troposphere Climate System". Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11578.
Testo completoAbstract (sommario):
Understanding the dynamical relationships between low frequency forcings and the interannual variability of the Earths atmosphere is critical for accurate extended-range forecasts and climate prediction. This thesis investigates possible dynamical couplings between the stratosphere and troposphere by implementing lagged multivariate linear regressions. These regressions were chosen to untangle the separate responses of distinct atmospheric forcings upon zonal mean climate variability. The regressions incorporate monthly meteorological data with indices of four dominant forcings of low frequency atmospheric variability: the El Nino Southern Oscillation, the Quasi-Biennial Oscillation, the 11-year solar cycle, and volcanic activity. The analysis uses data from both the NCAR/NCEP and ECMWF reanalyses for two distinct time periods to expose possible satellite measurement influences. One period consists of all data since 1958, while the other period includes only data since 1979, a period of extensive satellite observations. Diagnostic tools include piecewise potential vorticity inversions, an assessment of anomalous Eliassen-Palm fluxes, stream function analyses, and general circulation model diagnoses. The examination reveals robust patterns associated with each forcing, consistent with existing theories in climate dynamics of the coupling mechanisms between the stratosphere and the troposphere. To better predict climate variability, however, the next step is to investigate the nonlinearities known to play an important role in this system.
28
Hughes, John K. "The dynamic response of the global atmosphere-vegetation coupled system". Thesis, University of Reading, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397768.
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Fairhurst, Peter. "Towards a real-time tightly coupled GPS/INS positioning system". Thesis, University of Newcastle Upon Tyne, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446192.
Testo completo
30
Shrimpton, T. E. "A filing service for a close coupled distributed computer system". Thesis, University of Sussex, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379438.
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31
Birchfield, Neal Spencer. "STRUCTURAL MODIFICATION OF A COUPLED ROTORDYNAMIC SYSTEM FROM TRANSFER FUNCTIONS". Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1376320545.
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Withee, Jon E. "Fully coupled dynamic analysis of a floating wind turbine system". Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1471.
Testo completoAbstract (sommario):
CIVINSThe use of wind power is in a period of rapid growth worldwide and wind energy systems have emerged as a promising technology for utilizing offshore wind resources for the large scale generation of electricity Drawing upon the maturity of wind turbine and floater technologies developed by the wind energy and oil and gas industries, respectively, large offshore wind energy systems have been developed and are being proposed for operation in offshore areas where environmental restrictions are less restrictive, large wind resources exist, and open sea areas are available for wind farm development. A fully coupled dynamic analysis/technique was developed to predict the response of a floating wind turbine system in a stochastic wind and wave environment This technique incorporated both non-linear wave loading on the submerged floater and the aerodynamic loading on the wind turbine A tension leg spar buoy was designed to support the wind turbine This design was chosen due to its relatively small size and hence lower potential cost per wind turbine The system's tethers were attached to the ends of spokes which radiated out from the spar cylinder This arrangement of lines and spokes promised to be very stiff in the roll and pitch modes of motion.
33
Miller, Russell Lowell Kimble H. Jeff Kimble H. Jeff. "Characterization and control of a strongly-coupled atom-cavity system /". Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-05152009-142724.
Testo completo
34
Ngaradoumbe, Nanhornguè Ronel. "Sensitivity analysis applied to fem models for coupled multiphase system". Doctoral thesis, Università degli studi di Padova, 2010. http://hdl.handle.net/11577/3421559.
Testo completoAbstract (sommario):
Coupled multiphysics problems are very actual research topics in civil engineering. In this work we focus on multiphase models for concrete exposed to high temperature, applicable to the evaluation of re resistance in industrial and civil concrete structures.
Many non-linear phenomena and interactions are involved in concrete behaviour when temperatures higher than the standard ones are considered. Such phenomena involve
not only heat conduction and vapour diffusion, but also liquid water ow caused by pressure gradients, capillary effects, adsorbed water content gradients, as well as latent heat transfer due to water phase change inside the pores. Moreover, high temperatures induce severe micro-structural changes and several interacting physical and chemical phenomena, resulting in signicant changes of the material inner structure and properties.
During modelling of hygro-thermal-mechanical behaviour of concrete, one should use models considering possibly the whole complexity and mutual interactions of the analysed physical processes. The use of fully coupled multiphase models, based on mechanics of multiphase porous media, is therefore necessary to correctly predict the hygro, thermal, chemical and mechanical behaviour of this material, including damage effects.
These models are nevertheless very complex and sophisticated because they are dealing with several elds strongly coupled, they are characterized by sets of coupled, nonlinear, differential equations and they require a large number of material parameters. Moreover, as it is well known, the computer solution of such large set of equations needs
rather long computer times when applied to real life problems and can be therefore quite expensive. From this stems the necessity to reduce both the number of parameters to be determined accurately by experiments, and the computing time.
Hence, a sensitivity analysis of the model with respect to variations of its parameters is needed, to be able to distinguish how sensitive is the solution to variations of the parameters of the equation set. Such an analysis reveals which are the main control parameters in the model and which are the effects of parameter changes, suggesting which parameters should be determined in an accurate way and which can simply be
found from literature. The identication of parameters inuence should also allows to proceed to a simplication of the mathematical model (model reduction).
The aim of this thesis is the sensitivity analysis of a nite element model (Comes-HTC) for the analysis of the behaviour of concrete exposed to high temperature; the sensitivity analysis has been performed with the automatic differentiation (AD) technique.
The application of AD to the fem code Comes-HTC has allowed to develop an ecient tool for the computation of the sensitivity coecients, which has enabled to quantify the effect and relative importance of the material parameters with regards to the different model outputs. The results obtained allow for a better understanding of physical phenomena described by the Comes-HTC; they also highlight the full coupling between the hygral, thermal and mechanical eld that impacts on the link between model variables and material parameters.I problemi che accoppiano vari campi della sica sono temi molto attuali nell'ambito dell'ingegneria civile. Il presente lavoro prende in esame modelli multifase per lo studio di calcestruzzi sottoposti ad alte temperature, applicabili per la valutazione della resistenza al fuoco di strutture civili o industriali. Numerosi fenomeni non lineari interessano il comportamento del calcestruzzo quando si considerano temperature elevate; tali fenomeni riguardano non solo la conduzione di calore e la diffusione di vapore, ma anche il trasferimento di calore latente provocato dal cambiamento di fase dell'acqua all'interno dei pori ed il usso d'acqua causato da gradienti di pressione, da effetti capillari, da gradienti del contenuto di acqua adsorbita. Inoltre le alte temperature causano forti cambiamenti microstrutturali e fanno sì che si sviluppino diversi fenomeni sici e chimici interagenti fra di loro, che provocano variazioni signicative della struttura interna e delle proprietà del materiale. Nella modellazione del comportamento igro-termo-meccanico del calcestruzzo, si dovrebbero utilizzare modelli che considerano la complessità e le interazioni dei processi sici descritti in precedenza. L'utilizzo di modelli accoppiati multifase, basati sulla meccanica dei mezzi porosi, si dimostra pertanto uno strumento necessario per una corretta previsione del comportamento igrometrico, termico, chimico e meccanico di tale materiale. Questi modelli sono tuttavia molto complessi e sosticati, perché hanno a che fare con parecchi campi fortemente accoppiati, sono caratterizzati da sistemi accoppiati di equazioni differenziali non lineari e richiedono un gran numero di parametri del materiale. Inoltre, nelle applicazioni di interesse pratico, la soluzione numerica di tali sistemi di equazioni richiede notevoli tempi di calcolo risultando quindi piuttosto costosa. Nasce quindi l'esigenza di ridurre sia l'onere richiesto dalla determinazione sperimentale dei parametri necessari, sia i tempi computazionali. Per poter procedere in questo senso serve quindi un'analisi della sensitività del modello rispetto alla variazione dei suoi parametri, per poter individuare in che modo la soluzione venga inuenzata dalla variazione dei parametri che compaiono nei sistemi di equazioni. Tale analisi rivela quali sono i parametri che controllano il modello e quali sono gli effetti delle loro variazioni, permettendo quindi di individuare i parametri la cui determinazione precisa è essenziale per l'accuratezza dei risultati e distinguerli da quelli la cui determinazione può essere meno precisa o che possono essere reperiti in letteratura. Dopo aver eseguito tale analisi, si potrà procedere ad una semplicazione del modello matematico, con effetti beneci anche sui tempi di calcolo, ed avviare in questo modo un processo di "model reduction". Lo scopo di questa tesi è l'analisi di sensitività di un modello agli elementi finiti (Comes-HTC) per l'analisi del comportamento del calcestruzzo esposto ad alte temperature; l'analisi di sensitività è stata eettuata attraverso la differenziazione automatica (AD). L'applicazione di questa tecnica al codice fem Comes-HTC ha permesso di sviluppare uno strumento eciente per il calcolo dei coecienti di sensitività, attraverso il quale è stato possibile quanticare gli effetti e l'importanza relativa dei parametri del materiale sull'insieme di soluzioni calcolate dal modello. I risultati ottenuti hanno consentito una migliore comprensione dei fenomeni sici descritti dal codice Comes-HTC, evidenziando anche il forte accoppiamento tra il campo igrometrico, termico e meccanico che inuisce sul legame tra le variabili del modello e i parametri del materiale.
35
Ozturk, Alper. "Development, Implementation, And Testing Of A Tightly Coupled Integrated Ins/gps System". Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/4/1093087/index.pdf.
Testo completoAbstract (sommario):
This thesis describes the theoretical and practical stages through
development to testing of an integrated navigation system, specifically composed
of an Inertial Navigation System (INS), and Global Positioning System (GPS).
Integrated navigation systems combine the best features of independent systems
to bring out increased performance, improved reliability and system integrity. In an
integrated INS/GPS system, INS output is used to calculate current navigation
statesGPS output is used to supply external measurements, and a Kalman filter is used to provide the most probable corrections to the state estimate using both data. Among various INS/GPS integration strategies, our aim is to construct a tightly coupled integrated INS/GPS system. For this purpose, mathematical models of INS and GPS systems are derived and they are linearized to form system dynamics and system measurement models respectively. A Kalman filter is designed and implemented depending upon these models. Besides these, based on the given aided navigation system representation a quantitative measure for observability is defined using Gramians. Finally, the performance of the developed system is evaluated with real data recorded by the sensors. A comparison with a reference system and also with a loosely coupled system is done to show the superiority of the tightly coupled structure. Scenarios simulating various GPS data outages proved that the tightly coupled system outperformed the loosely coupled system from the aspects of accuracy, reliability and level of observability.
36
Agagu, Tosin. "Recommendation Approaches Using Context-Aware Coupled Matrix Factorization". Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/37012.
Testo completoAbstract (sommario):
In general, recommender systems attempt to estimate user preference based on historical data. A context-aware recommender system attempts to generate better recommendations using contextual information. However, generating recommendations for specific contexts has been challenging because of the difficulties in using contextual information to enhance the capabilities of recommender systems.
Several methods have been used to incorporate contextual information into traditional recommendation algorithms. These methods focus on incorporating contextual information to improve general recommendations for users rather than identifying the different context applicable to the user and providing recommendations geared towards those specific contexts.
In this thesis, we explore different context-aware recommendation techniques and present our context-aware coupled matrix factorization methods that use matrix factorization for estimating user preference and features in a specific contextual condition.
We develop two methods: the first method attaches user preference across multiple contextual conditions, making the assumption that user preference remains the same, but the suitability of items differs across different contextual conditions; i.e., an item might not be suitable for certain conditions. The second method assumes that item suitability remains the same across different contextual conditions but user preference changes. We perform a number of experiments on the last.fm dataset to evaluate our methods. We also compared our work to other context-aware recommendation approaches. Our results show that grouping ratings by context and jointly factorizing with common factors improves prediction accuracy.
37
Liu, Bainan. "Boundary Observer-based 0utput Feedback Control of Coupled Parabolic PDEs". Thesis, Bourges, INSA Centre Val de Loire, 2018. http://www.theses.fr/2018ISAB0011.
Testo completoAbstract (sommario):
Cette thèse vise à concevoir un contrôleur basé observateur au bord pour une classede systèmes modélisés par des équations aux dérivées partielles (EDP) paraboliquescouplées en utilisant la méthode dite backstepping. Grosso modo, la méthode dubackstepping pour les EDP consiste principalement à les transformer sous certainesformes faciles à analyser et à stabiliser à l’aide de contrôleurs ou d’observateurs. Cesformes seront appelées les systèmes cibles. Tout d’abord, ce travail considère un cassimple d’équations couplées avec des paramètres de diffusion constants. Pour ce cas,on met en évidence des conditions de stabilité moins contraignantes que les conditionsproposées dans la littérature sur ce sujet. De plus, pour le même cas, on conçoitune commande par retour d’état basé observateur. Ensuite, on donne une simulationsur un exemple pour prouver la consistance de la méthode proposée. Ce travail traiteégalement d’une classe de systèmes modélisés par équations de réaction-advectiondiffusionavec le même paramètre de diffusion constant en proposant des conditionsparticulières sur les systèmes cibles. Dans un second temps, on traite le cas des équationscouplées réaction-diffusion avec différentes diffusions. Cependant, comme lestermes de diffusions sont différents, il est plus difficile de calculer le noyau de la transformationbackstepping. Pour surmonter cette difficulté, on fait une hypothèse sur lenoyau qui définit la transformation backstepping. De plus, on conçoit également uncontrôleur basé observateur avec les mêmes conditions de stabilité proposées pour lesdeux premières situations. Ensuite, on utilise le principe de séparation pour concevoirun contrôleur basé observateur. Enfin, on utilise un modèle simplifié de réacteurtubulaire pour mettre en évidence la cohérence de la méthode proposée. Dans unetroisième partie, cette thèse étend ces résultats à une classe de systèmes modéliséspar des équations couplées de réaction-advection-diffusion à coefficients dépendantde la variable d’espace, ce qui rend la détermination du noyau de la transformationbackstepping plus difficile. Pour ce faire, on transforme les équations aux dérivéespartielles paraboliques qui définissent le noyau de la transformation en un ensembled’équations hyperboliques. Par conséquent, on peut prouver que le problème est bienposé en fixant des conditions aux limites appropriées pour la fonction noyau. De plus,on fournit également les conditions de stabilité pour les systèmes cibles. La performancede l’observateur proposé est illustrée sur un modèle numérique. Puis, on étendle contrôleur basé observateur aux systèmes EDP d’ordre fractionnaire. Enfin, desconclusions sont présentées avec quelques perspectivesThis thesis aims to design a boundary observer-based output feedback controllerfor a class of systems modelled by linear coupled parabolic PDEs by using the backsteppingmethod.Roughly speaking, the backstepping method for PDEs mainly consists oftransforming some kinds of PDEs into some particular PDEs, that are easy to analyzeand stabilize by using controllers or observers. This kind of particular PDEs will becalled target systems. Firstly, it considers an easy case of coupled reaction-diffusionequations with the same constant diffusion parameter. For this case, it proposes amore relaxed stability condition for the target system of the backstepping transformation.Moreover, for the same case, it designs a backstepping boundary observer-basedoutput feedback controller. Then, it takes an example to verify the proposed method.It also deals with a class of systems modelled by reaction-advection-diffusion equationswith the same constant diffusion parameter, which are realized by proposingparticular conditions on the target systems. Secondly, it deals with a kind of systemsmodelled by coupled reaction-diffusion equations with different diffusions. In a similarway, it designs a boundary observer for this kind of systems. However, due to thefact that the constant diffusions are not the same, it is more difficult to solve the kernelfunctions of the backstepping transformation than the same diffusion case. Forthis, an assumption on the kernel functions is made to enable us to solve the problem.Moreover, it also designs a backstepping boundary controller based on the proposedstability conditions. Those stability conditions are more relaxed than the conditionswe can find in the literatures on this topic. Then, based on the Separation Principle,it designs an observer-based output feedback controller. It takes a simplified modelof Chemical Tubular Reactor to highlight the proposed method. Thirdly, this thesisdesigns a boundary observer as a more general extension by studying a class of systemsmodelled by coupled reaction-advection-diffusion equations with spatially-varyingcoefficients, which is more challenged to solve kernel functions of the backsteppingtransformation. To achieve this, it transforms the parabolic kernel equations into a setof hyperbolic equations. Then, it proves the well-posedness by setting suitable boundaryconditions for the kernel functions. Moreover, it also provides the stability conditionsfor the target systems. The performance of the proposed observer is illustrated bytaking a numerical model. Fourthly, it extends the above backstepping observer-basedoutput feedback controller to fractional-order PDE systems. Finally, conclusions areoutlined with some perspectives
38
Fanning, Augustus F. "Studies of the ocean-atmosphere system using a coupled climate model". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32744.pdf.
Testo completo
39
Zheng, P. "Development of a fully coupled, unstructured grid, coastal morphodynamic model system". Thesis, University of Liverpool, 2017. http://livrepository.liverpool.ac.uk/3020596/.
Testo completoAbstract (sommario):
A new fully coupled, unstructured grid, three-dimensional coastal morphodynamic model system is developed in this research. Based on two original independent models, i.e. the original unstructured-grid version of the third generation spectral wave model Simulating WAves Nearshore (UnSWAN) and the original Finite Volume Coastal Ocean Model (FVCOM), the development of this model system is achieved by accomplishing the following procedures: Coupling UnSWAN with FVCOM to enable the full representation of the wave-current interaction in the nearshore region, by building a new wave-current coupling scheme based on the vortex-force (VF) approach to represent the wave-current interaction and developing a new coupling module to facilitate the communication between UnSWAN and FVCOM in the parallel computing and realise the model coupling procedure. A GLS turbulence model is also modified to better reproduce wave-breaking generated turbulence, together with a roller transport model to account for the effects of surface wave roller. An alternative wave model based on Mellor et al. is also implemented in the present model system. The original advection-diffusion (AD) module is modified for the representation of particle suspension and subsequent transport under the combined flows. In this module, the contribution of wave-induced stokes drift to particle transport is included which is absent in the original FVCOM model. A new bed load transport module based on the SANTOSS formulae is built to represent various processes within the oscillatory boundary layer. Based on the semi-unsteady "half-cycle" concept, this SANTOSS formulae distinguish the sediment transports during the positive “crest” and the negative “trough” half-cycles and have the advantages over the traditional steady ’equilibrium’ transport formula that many wave-induced unsteadiness effects are included, including the wave asymmetry, sediment grain size effects and etc. Finally, the wave, circulation, suspended sediment and bed-load transport modules are integrated into the fully coupled, three-dimensional coastal morphodynamic model system, in which a sediment continuity (Exner) equation is also included to resolve the morphology evolution.
40
Sheu, Shin-Pyng. "Bäcklund transformation and homoclinic solutions to the coupled nonlinear Schrödinger system". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1261505344.
Testo completo
41
Sheu, Shin-pyng. "Bäcklund transformation and homoclinic solutions to the coupled nonlinear Schrödinger system /". The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487779120910002.
Testo completo
42
Ransley, Edward Jack. "Survivability of wave energy converter and mooring coupled system using CFD". Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3503.
Testo completoAbstract (sommario):
This thesis discusses the development of a Numerical Wave Tank (NWT) capable of describing the coupled behaviour of Wave Energy Converters (WECs) and their moorings under extreme wave loading. The NWT utilises the open-source Computational Fluid Dynamics (CFD) software OpenFOAM(R) to solve the fully nonlinear, incompressible, Reynolds-Averaged Navier-Stokes (RANS) equations for air and water using the Finite Volume Method (FVM) and a Volume of Fluid (VOF) treatment of the interface. A method for numerically generating extreme waves is devised, based on the dispersively-focused NewWave theory and using the additional toolbox waves2Foam. A parametric study of the required mesh resolution shows that steeper waves require finer grids for mesh independence. Surface elevation results for wave-only cases closely match those from experiments, although an improved definition of the flow properties is required to generate very steep focused waves. Predictions of extreme wave run-up and pressure on the front of a fixed truncated cylinder compare well with physical measurements; the numerical solution successfully predicts the secondary loading cycle associated with the nonlinear ringing effect and shows a nonlinear relationship between incident crest height and horizontal load. With near perfect agreement during an extreme wave event, the reproduction of the six degree of freedom (6DOF) motion and load in the linearly-elastic mooring of a hemispherical-bottomed buoy significantly improves on similar studies from the literature. Uniquely, this study compares simulations of two existing WEC designs with scale-model tank tests. For the Wavestar machine, a point-absorber constrained to pitch motion only, results show good agreement with physical measurements of pressure, force and float motion in regular waves, although the solution in the wake region requires improvement. Adding bespoke functionality, a point-absorber designed by Seabased AB, consisting of a moored float and Power Take-Off (PTO) with limited stroke length, translator and endstop, is modelled in large regular waves. This represents a level of complexity not previously attempted in CFD and the 6DOF float motion and load in the mooring compare well with experiments. In conclusion, the computational tool developed here is capable of reliably predicting the behaviour of WEC systems during extreme wave events and, with some additional parameterisation, could be used to assess the survivability of WEC systems at full-scale before going to the expense of deployment at sea.
43
Sheu, Shin-pyng. "Bäcklund transformation and homoclinic solutions to the coupled nonlinear Schrödinger system /". Connect to resource, 1992. http://rave.ohiolink.edu/etdc/view.cgi?acc%5Fnum=osu1261505344.
Testo completo
44
Low, Zhen Ning. "High efficiency loosely coupled wireless power transfer system via magnetic induction". [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0024707.
Testo completo
45
Rock, Brevin Shae. "Two-patch predator-prey system coupled with migration of both species". View electronic thesis (PDF), 2009. http://dl.uncw.edu/etd/2009-3/Rockb/brevinrock.pdf.
Testo completo
46
Mays, Cristin Jean. "Ground-coupled heat pump systems: a pumping analysis". Kansas State University, 2012. http://hdl.handle.net/2097/15099.
Testo completoAbstract (sommario):
Master of ScienceDepartment of Architectural Engineering
Fred Hasler
Ground-coupled heat pump (GCHP) systems use the ground as a heat source or sink that absorbs heat from or rejects heat to the soil, respectively; this is referred to as the geothermal heat exchanger. Apart from the geothermal heat exchanger, there are two other main system components that make up a GCHP system: heat pumps and circulation pumps. This report studies four GCHP pumping systems and makes comparisons between the four using life-cycle cost analyses for six building models. The goal for this analysis was to discover commonalities between the models in order to provide designers insight into which pumping system is the most cost effective. The analysis was performed by first creating energy models to obtain system and zone load information, as well as system part-load data and geothermal heat exchanger performance. From the zone load information, heat pump selections were then performed to indicate the worst case piping path that is required for pump head calculations. Piping layouts were created to establish pipe lengths for the pump head calculations as well. Other piping components such as valves and fittings and the air separator pressure drops were also calculated. Once the pump head calculations were complete for each system, pump schedules were created. From there initial unit and installation costs were determined for each pump, as well as their replacement costs. The part-load data from the energy models were then used to obtain annual pump energy consumption and pump utility cost. Finally, assumptions were made to establish regular and preventative maintenance requirements for each pumping system. Initial and replacement unit costs, annual utility cost and regular and preventative maintenance costs were the components used in the life-cycle cost analysis. Each of these components was converted to 30-year projected costs and added to create a total life-cycle cost for each pumping system. Comparisons were then made and the results showed that a primary pumping system with VFD control and 100% redundancy was the most cost effective system. However, there are other considerations such as controllability, flexibility and availability that might persuade designers to choose one of the other alternate solutions.
47
Reeves, Kevin. "Dynamic-systems analysis of self-excitation associated with a capacitor-coupled substation (CCS) - induction machine system". Master's thesis, University of Cape Town, 2006. http://hdl.handle.net/11427/5116.
Testo completoAbstract (sommario):
Includes bibliographical references.The purpose of this thesis is therefore to establish the cause of SSR at the Meru-Petronet system, and other similar systems, and investigate various compensation techniques.
48
Burley, Jonathan Mark Anderson. "Magmatism and glacial cycles : coupled oscillations?" Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:c55a6d98-d222-46de-8500-1ad44d05be75.
Testo completoAbstract (sommario):
The Earth's climate system is driven by varying insolation from the Sun. The dominant variations in insolation are at 23 and 40 thousand year periods, yet for the past million years the Earth's climate has glacial cycles at approximately 100 kyr periodicity. These cycles are a coupled variation in temperature, ice volume, and atmospheric CO2. Somehow the Earth system's collective response to 23 and 40 kyr insolation forcing produces 100 kyr glacial-interglacial cycles. Generally it has been assumed that the causative mechanisms are a combination of ice dynamics (high ice reflectivity controlling temperature) and ocean circulation (changing carbon partitioning between the deep ocean and the atmosphere, and heat transport to the poles). However, these proposed mechanisms have not yet resulted in a compelling theory for all three variations, particularly CO2. This thesis explores the role of volcanic CO2 emissions in glacial cycles. I calculate that glacial-driven sea level change alters the pressure on mid-ocean ridges (MORs), changing their CO2 emissions by approximately 10%. This occurs because pressure affects the thermodynamics of melt generation. The delay between sea level change and the consequent change in MOR CO2 emissions is several tens-of-thousands-of-years, conceptually consistent with a coupled non-linear oscillation that could disrupt glacial cycles from a 40 kyr mode to a multiple of that period. I develop an Earth system model to investigate this possibility, running for approximately one million years and explicitly calculating global temperatures, ice sheet configuration, and CO2 concentration in the atmosphere. The model is driven by insolation, with all other components varying in response (and according to their own interactions). This model calculates that volcanism is capable of causing a transition to ̃100 kyr glacial cycles, however the required average volcanic CO2 emissions are barely within the 95% confidence interval. Therefore it is possible for volcanic systems and glacial cycles to form a 100 kyr coupled oscillation.
49
Wang, Yijia. "Optimization and Integration of Electric Vehicle Charging System in Coupled Transportation and Distribution Networks". Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/20179.
Testo completoAbstract (sommario):
With the development of the EV market, the demand for charging facilities is growing rapidly. The rapid increase in Electric Vehicle and different market factors bring challenges to the prediction of the penetration rate of EV number. The estimates of the uptake rate of EVs for light passenger use vary widely with some scenarios gradual and others aggressive. And there have been many effects on EV penetration rate from incentives, tax breaks, and market price. Given this background, this research is devoted to addressing a stochastic joint planning framework for both EV charging system and distribution network where the EV behaviours in both transportation network and electrical system are considered. And the planning issue is formulated as a multi-objective model with both the capital investment cost and service convenience optimized. The optimal planning of EV charging system in the urban area is the target geographical planning area in this work where the service radius and driving distance is relatively limited. The mathematical modelling of EV driving and charging behaviour in the urban area is developed.
50
O'Day, Joseph Patrick. "Investigation of a coupled Duffing oscillator system in a varying potential field /". Online version of thesis, 2005. https://ritdml.rit.edu/dspace/handle/1850/1212.
Testo completo