To see the other types of publications on this topic, follow the link: Gas discharge systems.
Dissertations / Theses on the topic 'Gas discharge systems'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 29 dissertations / theses for your research on the topic 'Gas discharge systems.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Love, Adrian. "Hollow core optical fibre based gas discharge laser systems." Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760983.
Full textAbstract:
The humble electrically pumped gas laser has undergone little development in its fifty year life span due to the lack of an effective method to confine light within a hollow waveguide of any appreciable length in which an electrical discharge could be contained. New technologies in the field of anti-resonant guiding hollow core fibres present an opportunity to re-invent the gas laser. A recent breakthrough in the field demonstrated that DC pumped glow discharges of a helium and xenon gas mixture could not only be sustained in such a fibre, but also exhibited signs of gain on a number of mid-IR neutral xenon laser lines. The research presented in this thesis is a continuation of that project. The system was redesigned to incorporate two mirrors so that a cavity could be constructed. The previously hinted at gain on the 3:51 μm xenon line was confirmed through a series of CW measurements of the cavity, as was a polarisation of the laser due to a polarisation dependent output coupler. Further observation of the discharges revealed that they were of a pulsed nature, and that the mid-IR laser light was present in the discharge afterglow. A response to the cavity mirrors was observed in this afterglow pulse on the 3:11 and 3:36 μm xenon lines in addition to the 3:51 μm line previously seen. Through fast detection a modulation of the output power due to cavity mode beating effects was detected. The high gain and narrow bandwidth of the xenon laser lines resulted in a frequency pulling effect, and the mode separation in the 'hot' laser cavity was measured to be lower than in the 'cold' cavity. It was observed through pressure optimisation experiments in helium-xenon that higher output powers could be achieved by using lower partial pressures of xenon. This was exploited with neon-xenon mixtures, where the lower ionisation potential of neon allowed a lower pressure of xenon. Discharges were also achieved in helium-neon and argon gas mixtures.
2
Shang, Weifeng. "A survey on pattern formation in DC gas discharge systems." [S.l.] : [s.n.], 2007. http://deposit.ddb.de/cgi-bin/dokserv?idn=985723483.
Full text
3
Hatcher, M. G. "COMAS development for concentration probing of gas phase discharge systems." Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637245.
Full textAbstract:
The work presented in this thesis describes the further development of the pump-probe laser spectroscopic technique known as Concentration-Modulated Absorption Spectroscopy (COMAS), concentrating on its use as an analytical tool for the investigation of various atomic systems. The systems analysed here include a direct current glow discharge with a lithium cathode, and a neon hollow cathode discharge lamp. The COMAS method necessitates the use of a Lock-In Amplifier (LIA) for signal derivation and output measurement. A substantial feature of the work presented here is concerned with the way in which COMAS signals are affected by phasing effects, and Chapter 2 concentrates on the relationship between COMAS signal generation and LIA measurement of that signal. Meaningful, quantitative analysis using COMAS generally requires the use of an accompanying absorbance measurement of the sample in question, and the development of COMAS has in fact been limited by the quality of such absorbance measurements. This problem is addressed in Chapter 3, which describes the investigation of two novel absorption techniques with a view to future use in conjunction with COMAS. With the theoretical and experimental basis to COMAS fully described in Chapter 4, the technique is subsequently used to probe the distribution of sputtered Li atoms in d.c. glow discharge for a variety of conditions. The results allow determination of the first experimentally derived values of thermalisation cross-sections in the gas phase, and provide valuable data for glow discharge modelling. In the final three chapters, the COMAS technique is significantly extended to incorporate analysis of dynamic 3-level systems. This development is approached theoretically in Chapter 6, and shows that certain extra parameters which affect COMAS signals require determination. The 3-level theoretical treatment is tested experimentally in Chapters 7 and 8 by investigation of a neon hollow cathode discharge, with the atomic neon electronic scheme providing an analogous 3-level system. The phase behaviour of the cw COMAS neon signals is briefly investigated in Chapter 8a.
4
Hassall, G. "Space charge layers in a double plasma machine." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303608.
Full text
5
Pashley, Nicholas C. "Ignition systems for lean burn gas engines." Thesis, University of Oxford, 1997. http://ora.ox.ac.uk/objects/uuid:b5fcf2d4-b27b-4b3b-a593-ee307ec80f3a.
Full textAbstract:
This thesis describes an experimental investigation into ignition systems, their effects on the combustion process, and how the discharge is affected by the prevailing pressure, temperature and flow. The work is divided into four main areas, a comprehensive literature review, engine testing for ignition system suitability, non-flow rig testing (including erosion) and flow rig testing. The literature review concluded that the most practical ignition system for lean burn gas engines will continue to be based on the spark plug, but in the medium to long term, laser ignition may become viable. The measurement of the HT voltage and current is not straightforward, and appropriate methods have been identified. Capacitive and inductive ignition system types were compared in lean and diluted conditions on a single cylinder research engine of modern design at different engine loads and speeds. It was found that the most beneficial ignition system was an inductive ignition system, although that for some conditions, capacitive systems induced better engine performance with a fraction of the stored energy of the inductive alternative. Non flow tests showed that the early part of the spark discharge is sensitive to pressure and temperature effects, and as a consequence, the latter stages of the discharge are also affected. A correlation has been developed, for use with conventional nickel electrode spark plugs, to predict breakdown voltage as a function of pressure, temperature and gap. Experiments were carried out at elevated pressures in a stream of flowing air with capacitive and inductive ignition systems. Different electrode designs and orientations were also compared. It was shown that when exposed to a flow field, the discharge can be stretched which results in a shortened spark duration; in some cases the electrode can shield the discharge from flow field effects. This work showed that flow through the spark gap is a hindrance to the spark process, especially for longer duration systems. However for flame kernel growth, the literature review identified that flow is beneficial, serving to convect the kernel away from the electrodes, reducing the heat transfer from the flame. Analysis of the glow voltage history in the pressurised flow rig has been used to develop a correlation relating the voltage, current, flow velocity, pressure and time. This correlation was used to analyse the velocity records from the spark plug in a firing engine. The predicted velocities and turbulence intensity were in agreement with independent measurements.
6
Okubo, Hitoshi, Diaa-Eldin A. Mansour, Hiroki Kojima, Naoki Hayakawa, and Fumihiro Endo. "Surface charge accumulation and partial discharge activity for small gaps of electrode/epoxy interface in sf6 gas." IEEE, 2009. http://hdl.handle.net/2237/13944.
Full text
7
Bateman, Samuel. "Hollow core fibre-based gas discharge laser systems and deuterium loading of photonic crystal fibres." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648951.
Full textAbstract:
Research towards the development of a gas-discharge fibre laser using noble gases, with target emission wavelengths in the mid-IR. Additional and separate work on gas treatment methods for managing the formation of photo-induced defects in silica glass.
8
Sheehe, Suzanne Marie Lanier. "Heat Release Studies by pure Rotational Coherent Anti-Stokes Raman Scattering Spectroscopy in Plasma Assisted Combustion Systems excited by nanosecond Discharges." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1401377491.
Full text
9
Kuptsov, Alexander. "Změna parametrů výbojových světelných zdrojů s frekvencí napájecího proudu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-219992.
Full textAbstract:
The master’s thesis is devoted to exploiting of gas-discharge lamps and their dependence on frequency of the supply current. The first part describes the theory of discharge, its types and properties, terms of its origin, and ways of its exploitation. The second part concerns electrical ballast systems of gas discharge light sources, inductive (reactive) and electronic ballasts, principles of their functioning, advantages and disadvantages, and the comparison of their properties. The following chapters deal with low-pressure and high-pressure gas-discharged lamps, compare their properties and describe exploitation of fluorescent lamps. Before conducting the experiment we have described the influence of frequency of the supply current on fluorescent tube lamps. Preparations for laboratory measuring have been also implemented. During the experiment the two types of lamps have been analyzed, the results of the research are summed up in the conclusion.
10
McKitterick, David. "Phonon probing of magnetically quantised 2D electron systems." Thesis, University of Nottingham, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359910.
Full text
11
Mufti, Anwar Hassan Ali. "Development of a portable optical sensor for detection of micro-discharges in SFâ†6 switchgear systems." Thesis, University of Salford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239980.
Full text
12
Joyce, AÌine Mary. "A versatile Langmuir probe system." Thesis, University of Ulster, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268571.
Full text
13
Mansour, D. A., T. Okusu, K. Nishizawa, H. Kojima, N. Hayakawa, F. Endo, and H. Okubo. "Comparison of Partial Discharge Characteristics for Different Defect Types in SF6 Gas Insulation System." IEEE, 2008. http://hdl.handle.net/2237/12057.
Full text
14
Kojima, H., N. Hayakawa, F. Endo, and H. Okubo. "Novel Measurement and Analysis System for Investigation of Partial Discharge Mechanism in SF_6 Gas." IEEE, 2008. http://hdl.handle.net/2237/12058.
Full text
15
Hayakawa, Naoki, Takashi Okusu, Kanako Nishizawa, Hiroki Kojima, Fumihiro Endo, Masanobu Yoshida, Katsumi Uchida, and Hitoshi Okubo. "Dependence of Partial Discharge Characteristics at Spacer Surface on Particle Size in SF_6 Gas Insulated System." IEEE, 2008. http://hdl.handle.net/2237/12060.
Full text
16
Dulac, Adrien. "A CFD Analysis towards Flow Characteristics of three Pre-swirler Designs." Thesis, KTH, Kraft- och värmeteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103890.
Full textAbstract:
Although pre-swirlers play a determinant role in the transport of air from stationary parts to rotating holes, knowledge about their actual performance is limited. Therefore, this paper aims to relate how the pre-swirler pressure drop affects the performance of different pre-swirlers in terms of discharge coefficient, adiabatic pre-swirl effectiveness, and swirl ratio. The results are extracted from numerical simulations carried out on three different designs, two guide vanes, and a nozzle. When available, the results are compared to experimental data. The guide vanes have shown similar responses to the pressure drop variations. Their discharge coefficients remain relatively insensitive with an average value of 97%. The swirl ratio range from 0.704 to 1.013 and 0.703 to 1.023 respectively for a pressure drop varying from 3 to 7 bars. The adiabatic pre-swirl effectiveness is of 96% and 94%, respectively, under steady state operation.The nozzle design has shown inferior performance as compared to the guide vane designs. Its discharge coefficient remains around 91% and the swirl ratio varies between 0.678 and 1.121 for a pressure drop ranging from 3 to 10 bars. Under steady state operation, the adiabatic pre-swirl effectiveness is 1.22. The influence of through-flows on the aforementioned parameters was also analyzed. It was observed that the through-flow deteriorates the performance of the pre-swirlers, whether in terms of dimensionless pre-swirl effectiveness, or swirl ratio. The discharge coefficient was however not affected.
17
Isaksson, Frida. "Pressure loss characterization for cooling and secondary air system components in gas turbines." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-64528.
Full textAbstract:
There is a constant struggle to increase the efficiency in gas turbines, where one method is to have a higher inlet temperature to the turbine. Often, this results in temperatures higher than the critical temperature of the materials, which makes cooling of the components an important part of the turbine. The cooling air is tapped from the compressor, and has hence required work while being compressed, but since it is removed from the thermodynamic cycle it will not provide any work in the turbine stages. Therefore, it is important to understand the losses in the cooling system to be able to use the smallest amount of cooling air possible, while still cool sufficiently to not decrease the turbine’s lifetime. The pressure losses in the cooling and secondary air systems are due to either friction or minor losses; contractions, expansions and bends. The losses can be described by a discharge coefficient, ; a rate of how close the actual mass flow is to the ideal mass flow, or a pressure loss coefficient, ; a rate of the pressure drop. In the cooling and secondary air systems there are orifices and cooling geometries. These can have different geometrical properties depending on application, and thereby have different heat transfer performances and causing a higher or lower pressure drop. At Siemens Industrial Turbomachinery AB, SIT AB, a one-dimensional in-house program named C3D is used for thermal calculations and calculations of flow properties of internal cooling flow networks. The program uses hydraulic networks consisting of nodes and branches to simulate the flow inside the components. Correlations used for describing pressure losses have been collected and divided depending on their valid ranges, with the aim to make pressure loss calculations easier. A MATLAB code have been developed, which, depending on input parameters, separates the correlations and returns a plot with the correlations that can be used. In order to make the code as useful as possible, a few assumptions were made; curve fitting of correlations which were only available as plots and interpolation to get larger valid ranges for some cases. These assumptions will influence the results, but the code will still be able to give an indication of which correlation to use, and hence, the objective is fulfilled. Simulations in one dimension are commonly used, since it is less time consuming than three-dimensional modelling. Therefore, with focus on the pressure losses, a one-dimensional model of a blade in the in-house program C3D has been evaluated using a three-dimensional model in the CFD program Ansys CFX. Also, two new models were created in C3D; both with geometrical properties and pressure loss coefficients adjusted to the CFX model, but the first model is using the same hydraulic network as in the evaluated, reference, model while the second is using a new network, built according to the streamlines in CFX. The resulting mass flows in the C3D models were compared to the mass flows in the CFX model, which ended in the conclusion that it is hard for the one-dimensional models to understand the complex, three-dimensional flow situations, even when adjusting them to the CFX model. Anyhow, the adjustments made the model somewhat closer to the three-dimensional case, and hence CFX should be used in an earlier stage when developing C3D models.
18
Karlsson, Kristoffer. "Gap Discharge Transducers in a Transit Time Flow Measurement System Designed for Harsh Environments." Doctoral thesis, Luleå tekniska universitet, EISLAB, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-16911.
Full textAbstract:
In this thesis, the potential of the gap discharge transducer is investigated as transducers in a time-of-flight gas flow measurement setup designed for harsh environments.In this thesis the gap discharge transducer is operated in two different modes, named spark discharge transducer and glow discharge transducer. The spark discharge transducer generates a spark over a gap while the glow discharge transducer generates a continuous glow discharge.Earlier studies show that the spark discharge transducer is very durable and a potent sound pulse emitter. This thesis continues these studies by incorporating the spark discharge transducer into a flow measurement system as a sound pulse emitter. Further more, the gap discharge transducer is investigated as a potential sound pulse receiver.As an emitter in a flow measurement system the spark discharge transducer was placed in a pipe with a variable flow in a laboratory environment. The transducer was set to generate sparks to create the sound pulse and standard piezoelectric receivers were used to capture the signal.As a receiver, the gap discharge transducer was tested in two experiments. In the first experiment the spark discharge transducer was placed in a vacuum chamber to test the dependence between breakdown voltage and pressure. The pressure change from a sound pulse might cause breakdown in the gap of the transducer if an initial voltage between the electrodes is set close enough to breakdown. The breakdown leads to a spark which can be used to determine when a sound pulse arrives. In the second experiment the transducer was set to generate a glow discharge. The glow discharge was then subjected to a sound source. The voltage and current of the glow discharge depends on the environmental conditions in the gap. Pressure changes from a sound pulse will then affect the air in the gap which in turn changes the voltage and current characteristics of the discharge. The change in voltage and/or current can then be used to determine when a sound pulse has arrived.The investigation shows that the spark discharge transducer is a potential sound pulse emitter in a flow measurement system and could be capable of determining a flow quite accurately. As a receiver, the spark discharge transducer show limited potential. The pressure change of a spark generated sound pulse requires the receiver to be set very close to the breakdown voltage. But that close to the determined breakdown voltage will very often cause the gap to breakdown spontaneously. The glow discharge transducer, on the other hand, show promising potential. The transducer is proven to be able to receive sound waves and has a sensitivity that is deemed compatible with the spark discharge transducer as a sound pulse emitter.Godkänd; 2014; 20140917 (krikar); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Kristoffer Karlsson Ämne: Industriell elektronik/Industrial Electronics Avhandling: Gap Discharge Transducers in a Transit Time Flow Measurement System Designed for Harsh Enviroments Opponent: Professor Per Lunde, Department of Physics and Technology, University of Bergen, Norge Ordförande: Professor Jerker Delsing, EISLAB, Institutionen för System- och rymdteknik, Luleå tekniska universitet Tid: Måndag den 17 november 2014, kl 12:30 Plats: A1545, Luleå tekniska universitet
19
Starling, Elizabeth Rose. "Detection and Mitigation of Propagating Electrical Discharges Within the Gas Electron Multiplier Detectors of the CMS Muon System for the CERN HL-LHC." Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/315833.
Full textAbstract:
In preparation for the High-Luminosity Large Hadron Collider (HL-LHC) at CERN, the Compact Muon Solenoid (CMS) Detector is undergoing a series of upgrades to its existing infrastructure, and is adding in several completely new subdetector systems. The first of these new systems, called GE1/1, is a series of 144 gas electron multiplier (GEM) detectors, arranged as 36 two-detector "superchambers" in each of the muon endcaps of CMS. These detectors are a subtype of micropattern gas detectors, and consist of three layers of "GEM foils", thin sheets of polyimide coated with 5 um of copper on each side and chemically etched with holes of 50 - 70 um diameter at a pitch of 140 um. These layers are stacked on top of a printed circuit board (PCB) readout and sealed within a gastight volume that is filled with Ar:CO2 70:30, and a high voltage is applied to the foils to create electric fields within the GEM detectors. When a muon enters the detector and ionizes the gas within, the ionized electrons encounter these fields and multiply in Townsend avalanches at each successive foil layer, until they are read out at the readout PCB at a gain of ~10^4. In early 2017, a demonstrator system known as the "slice test" was installed into the negative endcap. Consisting of 10 GEM detectors, the two-year-long slice test served as both a proof of concept for the GE1/1 system and an invaluable learning experience that would permanently impact not only the GE1/1 project, but future GEM systems GE2/1 and ME0 as well. During the slice test, it was observed that readout channels were being lost in the course of operation to such a degree that the operational lifetime of the system was in serious jeopardy. These losses were attributed to damage to the front-end readout ASIC (VFAT) inputs, caused propagating electrical discharges within the detectors, and a dedicated campaign to study the discharges was launched. The results of this study will be presented in this dissertation. A campaign to mitigate these discharges and their resulting damage was launched. In order to protect the sensitive VFAT from damage, several external protection circuits were proposed and thoroughly tested. The results of these tests, which are presented herein, determined that a series of resistors totaling 470 Ohms would be installed on the VFAT hybrid. When coupled with an additional 200 kOhm resistor on the HV filter, this reduced the probability of damage following a discharge from 93% to 3% As GE2/1 and ME0 are not due to be installed for another few years, more complex discharge-prevention measures can be put into place. As such, the following measures have been examined, and results will be discussed herein: A new, larger VFAT hybrid is being manufactured, whose larger surface area can accommodate more robust protection circuits than those considered and used for GE1/1. As well, double-segmented GEM foils, in which both the top and bottom of each foil is segmented into < 100 cm^2 sectors that are separated by resistors, were examined for use in the detectors. These double-segmented foils were found to introduce a cross-talk signal in the detectors that results in false signals being treated as true signals, which causes a saturation of the GEM bandwidth and results in unwanted dead time. These cross-talk signals, as well as the compromises made to reduce the cross-talk while maintaining robust discharge prevention, will be discussed.Doctorat en Sciences
info:eu-repo/semantics/nonPublished
20
Hayakawa, N., T. Kobayashi, M. Hazeyama, T. Takahashi, K. Yasuda, and H. Okubo. "Partial discharge inception characteristics of LN/sub 2//polypropylene laminated paper composite insulation system for high temperature superconducting cables." IEEE, 2005. http://hdl.handle.net/2237/6846.
Full text
21
Yan, Ning. "High-frequency Current-transformer Based Auxiliary Power Supply for SiC-based Medium Voltage Converter Systems." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/101507.
Full textAbstract:
Auxiliary power supply (APS) plays a key role in ensuring the safe operation of the main circuit elements including gate drivers, sensors, controllers, etc. in medium voltage (MV) silicon carbide (SiC)-based converter systems. Such a converter requires APS to have high insulation capability, low common-mode coupling capacitance (Ccm ), and high-power density. Furthermore, considering the lifetime and simplicity of the auxiliary power supply system design in the MV converter, partial discharge (PD) free and multi-load driving ability are the additional two factors that need to be addressed in the design. However, today’s state-of-the-art products have either low power rating or bulky designs, which does not satisfy the demands. To improve the current designs, this thesis presents a 1 MHz isolated APS design using gallium nitride (GaN) devices with MV insulation reinforcement.
By adopting LCCL-LC resonant topology, the proposed APS is able to supply multiple loads simultaneously and realize zero voltage switching (ZVS) at any load conditions. Since high reliability under faulty load conditions is also an important feature for APS in MV converter, the secondary side circuit of APS is designed as a regulated stage. To achieve MV insulation (> 20 kV) as well as low Ccm value (< 5 pF), a current-based transformer with a single turn structure using MV insulation wire is designed. Furthermore, by introducing different insulated materials and shielding structures, the APS is capable to achieve different partial discharge inception voltages (PDIV). In this thesis, the transformer design, resonant converter design, and insulation strategies will be detailly explained and verified by experiment results.
Overall, this proposed APS is capable to supply multiple loads simultaneously with a maximum power of 120 W for the sending side and 20 W for each receiving side in a compact form factor. ZVS can be realized regardless of load conditions. Based on different insulation materials, two different receiving sides were built. Both of them can achieve a breakdown voltage of over 20 kV. The air-insulated solution can achieve a PDIV of 6 kV with Ccm of 1.2 pF. The silicone-insulated solution can achieve a PDIV of 17 kV with Ccm of 3.9 pF.M.S.
Recently, 10 kV silicon carbide (SiC) MOSFET receives strong attention for medium voltage applications. Asit can switch at very high speed, e.g. > 50 V/ns, the converter system can operate at higher switching frequency condition with very small switching losses compared to silicon (Si) IGBT [8]. However, the fast dv/dt noise also creates the common mode current via coupling capacitors distributed inside the converter system, thereby introducing lots of electromagnetic interference (EMI) issues. Such issues typically occur within the gate driver power supplies due to the high dv/dt noises across the input and output of the supply. Therefore, the ultra-small coupling capacitor (<5 pF) of a gate driver power supply is strongly desired.[37] To satisfy the APS demands for high power modular converter system, a solution is proposed in this thesis. This work investigates the design of 1 MHz isolated APS using gallium nitride (GaN) devices with medium voltage insulation reinforcement. By increasing switching frequency, the overall converter size could be reduced dramatically. To achieve a low Ccm value and medium voltage insulation of the system, a current-based transformer with a single turn on the sending side is designed. By adopting LCCL-LC resonant topology, a current source is formed as the output of sending side circuity, so it can drive multiple loads importantly with a maximum of 120 W. At the same time, ZVS can use realized with different load conditions. The receiving side is a regulated stage, so the output voltage can be easily adjusted and it can operate in a load fault condition. Different insulation solutions will be introduced and their effect on Ccm will be discussed. To further reduce Ccm, shielding will be introduced. Overall, this proposed APS can achieve a breakdown voltage of over 20 kV and PDIV up to 16.6 kV with Ccm<5 pF. Besides, multi-load driving ability is able to achieve with a maximum of 120 W. ZVS can be realized. In the end, the experiment results will be provided.
22
Yu, Defen. "Study of electric discharge and space charge formation phenomena in the air gaps of an ice-covered insulator using an icicle/ice-covered plate electrode system = Étude des processus des décharges électriques et formation de charges d'espace dans les intervalles d'air d'un isolateur recouvert de glace à l'aide d'une configuration d'électrodes glaçon/plaque recouverte de glace /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2007. http://theses.uqac.ca.
Full textAbstract:
Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2007.La p. de t. porte en outre: Thèse présentée à l'Université du Québec à Chicoutimi comme exigence partielle du doctorat en ingénierie. CaQQUQ Bibliogr.: f. 222-239. Document électronique également accessible en format PDF. CaQQUQ
23
Shang, Weifeng [Verfasser]. "A survey on pattern formation in DC gas discharge systems / vorgelegt von Weifeng Shang." 2007. http://d-nb.info/985723483/34.
Full text
24
Liao, Zi-Jie, and 廖子傑. "gallium nitride nanowires enhanced gas discharge luminance system." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/09166250186334017096.
Full textAbstract:
碩士大同大學
光電工程研究所
98
We produced a gas discharge luminance system which has gallium nitride nanowires embedded on electrodes. These nanostructures can enhance the field emission process to reduce plasma ignition voltages. Gallium has the atomic structure similar to mercury which can be used in the high intensity discharge luminance system to capture electrons in order to reduce electron bombardment at electrodes. The gallium nitride nanowires grown on silicon substrates by vapor-liquid-solid(VLS) mechanism. Scanning electron microscope, tunneling electron microscope energy diffraction spectrum were employed to analysis their crystalline structure and forming elements. The results show that gallium nitride nanowires have wurzite structure, and the forming elements have oxygen, gallium and nitrogen. The exacter of gallium ion in plasma tube was confirmed by optical emission spectroscopy (OES). Compare to the conventional luminance system, the experimental system assistant by gallium nitride nanowires exhibits the lower input current. This gallium nitride nanowires embedded system improved power utility. By releasing gallium ions into the tube, it can replace the mercury in the system to improve the power consumption and created a environmental friendly lighting tool suitable for modern luminance device.
25
Hsieh, Chih-Hung, and 謝志宏. "Gas effect of decoloration by pulsed streamer discharge system." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/q5642e.
Full textAbstract:
碩士龍華科技大學
工程技術研究所
96
Because of toxicity and color of waste water of dye, the removal of the containment of the waste water is main environmental concerning problems of the textile industry. Pulsed streamer discharge under the water could be one solution for decoloration of dye. In this work, the different gases were induced into reactor through the needle hole which is positive charged. The influence of gas species was found by measuring the decoloration rate. Decoloration reaction was most effective with oxygen gas than air、co2 and argon. Oxygen was found is the most effective gas for the decoloration process, the decoloration process of Chicago sky blue organic dye occurs due to the break up of the azo bond (N=N) by OH radicals, OH radicals were examined for studying the mechanism of the decoloration.
26
Liang, Wei-Hao, and 梁偉豪. "Preliminary Experimental Investigation of a DC Gas Discharge With and Without Magnetron System." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/76005548637262812184.
Full textAbstract:
碩士國立交通大學
機械工程系所
94
In the recent years, the field of gas discharge plasma applications has rapidly expanded in semiconductor industry. The dc discharges has been applied in generating weakly ionized plasmas and has been studied the properties of plasma. The dc glow discharges have been used as the sputtering source to product thin film and other specialized application for a long time. As illustration in the Paschen curve, the pressure that discharges exceed breakdown voltage must be high enough ( ) and maintain in the usually manner by the secondary electron emission from the cathode. These pressures are higher than the optimum for deposition of sputtered atoms onto the substrate. This results in sputtered atom poor adhesion for the sputtered film. It is desirable to operate a sputtering discharge at lower pressures than to be obtained in a conventional glow discharge. This has led to the use of a dc magnetic field at cathode to confine the secondary electrons. This research will use Langmuir probe to measure the properties of dc discharges in the condition with and without magnetron and compare the difference between this two conditions.
27
Bechtold, Jean-Philippe. "The design of a zero-effluent discharge system for Westcoast Energy inc.’s Fort Nelson Gas Plant." Thesis, 1995. http://hdl.handle.net/2429/4503.
Full textAbstract:
This project was initiated by Westcoast Energy Inc. (Westcoast) to examine the feasibility of
transforming their Fort Nelson Gas Plant (FNGP) into a zero-effluent discharge (ZED) facility.
Water flow and water chemistry data were collected at the plant. The resulting data set was used to
identify water leaks in the existing distribution network, as well as to identify methods of
optimizing water use at this facility. Designs for implementing a Z ED protocol at the FNGP were
then developed and subsequently evaluated with a computer simulator.
A total of 18 Z E D models were constructed using reverse osmosis (RO) membranes,
nanofilters and other Z ED technology. The final disposal mechanism in 10 of the 18 scenarios was
a brine concentrator - spray dryer (BCS) assembly, which reduced all remaining wastewater into a
solid waste. In the other 8 Z ED designs, final concentrates were disposed of in a deep well. The
best deep well configuration was a 1-stage RO filter; the necessary equipment, excluding the deep
well, would cost an estimated $101 700 US dollars. The best BCS scenarios were a 1-stage R O
and a BCS-only models; they would cost around $1.61 and $1.79 million US dollars,
respectively. A step by step approach by which the FNGP can be transformed into a Z ED facility
is detailed in Chapter 8.0 of this report.
While it is possible to implement a Z ED program at the FNGP, there are consequences to this
course of action which need to be considered. The most important is final waste management.
Regardless of whether a deep well or a BCS unit is used, either system will have to be built and
operated in such a way that the final waste products produced by the Z ED treatment train do not
migrate off-site, as this action would violate the Z ED principle. Once a Z E D program is initiated,
wastewater and/or waste solids produced at the FNGP will no longer disappear with the FNR;
they will remain on-site indefinitely.
28
Fylan, Beth, Iuri Marques, Hanif Ismail, Liz Breen, P. Gardner, Gerry R. Armitage, and Alison Blenkinsopp. "Gaps, traps, bridges and props: a mixed-methods study of resilience in the medicines management system for heart failure patients at hospital discharge." 2018. http://hdl.handle.net/10454/16745.
Full textAbstract:
YesPoor medicines management places patients at risk, particularly during care transitions. For patients with heart failure (HF), optimal medicines management is crucial to control symptoms and prevent hospital readmission. This study explored the concept of resilience using HF as an example condition to understand how the system compensates for known and unknown weaknesses. We explored resilience using a mixed-methods approach in four healthcare economies in the north of England. Data from hospital site observations, healthcare staff and patient interviews, and documentary analysis were collected between June 2016 and March 2017. Data were synthesised and analysed using framework analysis. Interviews were conducted with 45 healthcare professionals, with 20 patients at three timepoints and 189 hours of observation were undertaken. We identified four primary inter-related themes concerning organisational resilience. These were named as gaps, traps, bridges and props. Gaps were discontinuities in processes that had the potential to result in poorly optimised medicines. Traps were features of the system that could produce errors or unintended adverse medication events. ‘Bridges’ were features of the medicines management system that promoted safety and continuity which ensured that, despite varying conditions, care could be delivered successfully. ‘Props’ were informal, temporary or impromptu actions taken by patients or healthcare staff to avoid potential adverse events. The numerous opportunities for HF patient safety to be compromised and sub-optimal medicines management during this common care transition are mitigated by system resilience. Cross-organisational bridges and temporary fixes or ‘props’ put in place by patients and carers, healthcare teams and organisations are critical for safe and optimal care to be delivered in the face of continued system pressures.
29
Yu, Defen. "Study of electric discharge and space charge formation phenomena in the air gaps of an ice-covered insulator using an icicle/ice-covered plate electrode system = Étude des processus des décharges électriques et formation de charges d'espace dans les intervalles d'air d'un isolateur recouvert de glace à l'aide d'une configuration d'électrodes glaçon/plaque recouverte de glace." Thèse, 2007. http://constellation.uqac.ca/401/1/030007983.pdf.
Full textAbstract:
Dans les régions au climat froid, les accumulations de glace sur les isolateurs diminuent leur performance électrique, résultant parfois en contournements et pannes d'électricité. Ce problème a attiré l'attention de nombreux chercheurs et a amené à la publication de nombreux articles et rapports. On a découvert que l'un des signes les plus courants associés aux isolateurs recouverts de givre est la présence d'intervalles d'air le long de la surface de glace, causés par l'activité des décharges couronne.
La décharge couronne à la pointe des glaçons dans l'intervalle d'air est la première étape du processus de contournement. Durant ces activités de décharges de couronne, un grand nombre de charges d'espace, incluant les ions positifs et négatifs, sont générés, ce qui influence la distribution du champ électrique dans les intervalles d'air ainsi que les activités de décharges séquentielles conséquentes. Cependant, dû aux propriétés invisibles et à la complexité des décharges d'espace, son influence sur la distribution du champ électrique et sur le processus de contournement a été généralement ignorée dans les études antérieures.
Cette thèse de doctorat vise à étudier les processus fondamentaux et initiaux des décharges électriques dans les intervalles d'air des isolateurs recouverts de givre. Ce travail a été effectué dans le cadre des activités de la Chaire industrielle NSERC/Hydro-Québec/UQAC sur le givrage atmosphériques des équipements des réseaux électriques (CIGELE) et de la Chaire du Canada sur l'ingénierie du givrage des réseaux électriques (INGIVRE) à l'Université du Québec à Chicoutimi, en collaboration avec le Key Laboratory of High Voltage Engineering and Electrical New Technology of the Ministry of Education à l'Université de Chongqing. Dans le but de simplifier l'étude, un modèle physique, un système d'électrode recouvert de glace, a été conçu sur la base de nombreuses investigations antérieures pour simuler la pointe des glaçons et la surface glacée d'isolateurs réels recouverts de glace. À cette fin, des tests systématiques ont été effectués dans une chambre climatique du laboratoires de haute tension de l'Université de Chongqing. Utilisant un système d'acquisition de données consistant en une caméra à ultraviolets CoroCam IV* et un détecteur de pulsations de courant spécialement conçu à cette fin, les caractéristiques des décharges de couronne tel que la tension de seuil de la décharge couronne, le volume d'apparition de couronne, le taux de répétition des impulsions de décharge et de variation du courant ont été analysés en détail selon différents paramètres. Ces paramètres incluent les intervalles d'air, la température ambiante, la conductibilité de l'eau de congélation, la pression atmosphérique et la polarité du voltage ainsi que les types de voltages. Par la suite, les résultats expérimentaux ont été soumis à l'analyse statistique et l'influence de ces paramètres sur les caractéristiques des pulsations de décharge a été déterminée.
Dans le but de mettre en lumière le mécanisme physique sous-jacent les décharges couronne et de déterminer l'influence des charges d'espace sur les processus de décharge induits, un modèle physique de charges d'espace dynamique a été proposé pour analyser le phénomène de décharge. Un modèle mathématique a été élaboré pour simuler le processus de dérivation et de diffusion des nuages de charge d'espace. Ce modèle permet de calculer et de valider le temps critique des charges d'espace. Finalement, les influences possibles des charges d'espace sur le contournement des isolateurs recouverts de glace sont discutées.
Les résultats de l'étude donnent une meilleure compréhension des décharges de couronne à la poine des glaçons accumulés sur les isolateurs recouverts de glace. Cependant, dû à la limite de temps et à la complexité de ce phénomène, des études plus approfondies seront nécessaires pour compléter le modèle et la théorie. Plusieurs recommandations ont été proposées pour de futures études.