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Miller, Christopher J. "An Additive Printing Process for Conductive Structures Based on Low Pressure Argon Plasma Treatment of Silver Nitrate-based Inks." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1497046125099719.
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Roth, Jan. "Funktionalisierung von Silikonoberflächen." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1234268177738-70409.
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Poly(dimethylsiloxan) (PDMS) ist ein wichtiges Polymer, das zunehmend in der Mikroelektronik aufgrund seiner hervorragenden Elastizität und thermischen Stabilität Verwendung findet. Ein limitierender Faktor für den Einsatz von PDMS ist aufgrund des Fehlens von reaktiven Gruppen und der niedrigen freien Oberflächenenergie seine geringe Adhäsion zu anderen Materialien. Zur Erhöhung der Adhäsion ist deshalb die Einführung von polaren, funktionellen Gruppen notwendig. Hier lag die Motivation der vorliegenden Arbeit, die sich eine gezielte Funktionalisierung von PDMS-Oberflächen als Aufgabe gesetzt hatte. Im ersten Teil der Arbeit wurde eine Verbesserung der Adhäsion zu einem fotostrukturierbaren Epoxidharz mittels der Sauerstoff- und Ammoniakplasmabehandlung angestrebt. In beiden Fällen führte die Plasmabehandlung zu der Einführung von unterschiedlichsten funktionellen Gruppen auf die Oberfläche und zu einer Verbesserung des Benetzungsverhaltens gegenüber Wasser. Zudem wurden Haftfestigkeiten erzielt, die um ein Vielfaches höher waren als jene zwischen Epoxidharz und einer unbehandelten PDMS-Oberfläche. Jedoch waren die hydrophilen Eigenschaften nach der Plasmabehandlung während der Lagerung an Luft zeitlich begrenzt, die PDMS-Oberfläche kehrt innerhalb kurzer Zeit in den einst hydrophoben Ausgangszustand zurück. Der Alterungsvorgang wird als „Hydrophobic Recovery“ bezeichnet und ist bei PDMS-Oberflächen, die höheren Plasmaleistungen und Behandlungszeiten ausgesetzt wurden, besonders auffällig. Die Vermeidung dieser Problematik war der Ausgangspunkt für den zweiten Teil der Arbeit. Auf der Grundlage der über die Plasmabehandlungen erzeugten funktionellen Gruppen wurden neue Konzepte für eine kovalente Anbindung von verschiedenen funktionellen Homo- und Copolymeren über die „Grafting to“-Technik entwickelt. Neben der Erhöhung der Adhäsion zu dem Epoxidharz war es möglich, das Benetzungsverhalten gegenüber Wasser durch die Unterbindung der „Hydrophobic Recovery“ zu stabilisieren. Des Weiteren gelang es, durch die Wahl der funktionellen Polymere, die PDMS-Oberfläche gezielt mit gewünschten Eigenschaften auszustatten. Somit ist der Einsatz der polymermodifizierten Oberflächen, außer in der Mikroelektronik, auch auf andere Anwendungen, wie der Biomedizin, der Mikrofluidik oder der Softlithografie übertragbar, in denen eine beständige, definierte Oberflächenfunktionalisierung ein wichtiges Kriterium darstellt.
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Roth, Jan. "Funktionalisierung von Silikonoberflächen." Doctoral thesis, Technische Universität Dresden, 2008. https://tud.qucosa.de/id/qucosa%3A23701.
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Poly(dimethylsiloxan) (PDMS) ist ein wichtiges Polymer, das zunehmend in der Mikroelektronik aufgrund seiner hervorragenden Elastizität und thermischen Stabilität Verwendung findet. Ein limitierender Faktor für den Einsatz von PDMS ist aufgrund des Fehlens von reaktiven Gruppen und der niedrigen freien Oberflächenenergie seine geringe Adhäsion zu anderen Materialien. Zur Erhöhung der Adhäsion ist deshalb die Einführung von polaren, funktionellen Gruppen notwendig. Hier lag die Motivation der vorliegenden Arbeit, die sich eine gezielte Funktionalisierung von PDMS-Oberflächen als Aufgabe gesetzt hatte. Im ersten Teil der Arbeit wurde eine Verbesserung der Adhäsion zu einem fotostrukturierbaren Epoxidharz mittels der Sauerstoff- und Ammoniakplasmabehandlung angestrebt. In beiden Fällen führte die Plasmabehandlung zu der Einführung von unterschiedlichsten funktionellen Gruppen auf die Oberfläche und zu einer Verbesserung des Benetzungsverhaltens gegenüber Wasser. Zudem wurden Haftfestigkeiten erzielt, die um ein Vielfaches höher waren als jene zwischen Epoxidharz und einer unbehandelten PDMS-Oberfläche. Jedoch waren die hydrophilen Eigenschaften nach der Plasmabehandlung während der Lagerung an Luft zeitlich begrenzt, die PDMS-Oberfläche kehrt innerhalb kurzer Zeit in den einst hydrophoben Ausgangszustand zurück. Der Alterungsvorgang wird als „Hydrophobic Recovery“ bezeichnet und ist bei PDMS-Oberflächen, die höheren Plasmaleistungen und Behandlungszeiten ausgesetzt wurden, besonders auffällig. Die Vermeidung dieser Problematik war der Ausgangspunkt für den zweiten Teil der Arbeit. Auf der Grundlage der über die Plasmabehandlungen erzeugten funktionellen Gruppen wurden neue Konzepte für eine kovalente Anbindung von verschiedenen funktionellen Homo- und Copolymeren über die „Grafting to“-Technik entwickelt. Neben der Erhöhung der Adhäsion zu dem Epoxidharz war es möglich, das Benetzungsverhalten gegenüber Wasser durch die Unterbindung der „Hydrophobic Recovery“ zu stabilisieren. Des Weiteren gelang es, durch die Wahl der funktionellen Polymere, die PDMS-Oberfläche gezielt mit gewünschten Eigenschaften auszustatten. Somit ist der Einsatz der polymermodifizierten Oberflächen, außer in der Mikroelektronik, auch auf andere Anwendungen, wie der Biomedizin, der Mikrofluidik oder der Softlithografie übertragbar, in denen eine beständige, definierte Oberflächenfunktionalisierung ein wichtiges Kriterium darstellt.
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Jones, Tony Lee. "Interaction of liquid droplets with low-temperature, low-pressure plasma." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04072005-144736/.
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Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2005.Said I. Abdel-Khalik, Committee Chair ; Sheldon M. Jeter, Committee Member ; Minami Yoda, Committee Member. Includes bibliographical references.
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Blacknell, Hannah Irene. "Modification of PTFE using low-pressure and atmospheric-pressure plasma methods." Thesis, Durham University, 2018. http://etheses.dur.ac.uk/12759/.
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As an inherently chemically inert and physically stable polymer, PTFE has the potential to be used in medical applications as replacement ligaments or vascular stents. In the work presented in this thesis, atmospheric and low-pressure plasma processes were used to modify PTFE surfaces without altering the bulk properties of the substrate. The coupling of two low-pressure gas plasma treatments together into a two-step process was investigated as a method of producing a stable hydrophilic PTFE surface. A roughening oxygen plasma treatment was used to create a high water contact angle (WCA) Cassie-Baxter surface, before an ammonia plasma treatment transformed it into a hydrophilic Wenzel state. Although these surfaces initially exhibited a WCA of < 10°, solvent washing caused significant hydrophobic recovery which was attributed to the washing off of low molecular weight oxidised species (LMWOS). Economically, an atmospheric-pressure plasma process is industrially favourable to low-pressure methods. The simple equipment required for a dielectric barrier discharge (DBD) process means that PTFE modification could be carried out in situ to prevent contamination or hydrophobic recovery being an issue in surgeries. The work presented here produced surfaces with a stable surface potential, the polarity of which was determined by the feed gas. Doping in water and/or ammonia molecules into inert feed gases was found to change the polarity of the surface potential. The use of the theory of electrowetting to decrease the WCA of DBD plasma-treated surfaces was successful, although only a small decrease in WCA was observed on the charged surfaces. However, the surface potential of the substrates was used to initialise the grafting and subsequent polymerization of a number of monomers, as well as deposition of a sulfobetaine zwitterionic layer. The lowest WCA was produced by the dipping of DBD-charged PTFE substrates into an aqueous sulfobetaine solution which produced a WCA of < 10° recovering to 39° after solvent washing. The methods described in this thesis present a number of ways in which stable hydrophilic PTFE surfaces can be produced: an effective low-pressure treatment altered the wetting state of the surface using roughening effect, and DBD plasma-treated surfaces used the surface potential imparted by the plasma to initialise further grafting processes to achieve stable hydrophilicity.
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Scheubert, Peter. "Modelling and diagnostics of low pressure plasma discharges." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966327535.
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Diaper, Clare. "Low pressure nanofiltration membranes for dyehouse effluent treatment." Thesis, Cranfield University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284922.
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Yang, Suidong. "Diagnostics and modelling of an inductively coupled RF low-pressure low-temperature plasma." Thesis, n.p, 1998. http://oro.open.ac.uk/19841/.
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Jiansirisomboon, Sukanda. "Low pressure plasma spraying of alumina/silicon carbide nanocomposite coatings." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.393389.
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Hurd, Sarah M. "Low-pressure reverse osmosis membrane treatment of landfill leachate." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0025/MQ52299.pdf.
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Lee, Kyoung Ook. "Coaxial Atmospheric Pressure Plasma Discharge for Treatment of Filaments and Yarns." NCSU, 2008. http://www.lib.ncsu.edu/theses/available/etd-12242007-142129/.
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Characteristics of non-thermal atmospheric-pressure plasma generated in a coaxial cylindrical Dielectric-Barrier Discharge (DBD) were investigated for application in treatment of polymer and 100% un-mercerized cotton yarns. The discharge characteristics were investigated by measuring the electrical parameters and utilization of developed plasma circuit models to obtain plasma electron temperature, number density and the electron-neutral collision frequency. The experiments were conducted in helium and oxygenated helium plasma in absence and presence of yarns. The discharge is capacitively-coupled and is induced by an audio-frequency, 4.5 kHz, oscillating voltage. The electrical voltage-current (V-I) characteristics optimized for plasma processing, by the oxygen and helium flow rate ratio, was found to be about 40sccm for oxygen flow. Optical emission spectroscopy (OES) was used to determine the plasma composition and to evaluate plasma temperature and number density. The plasma electron number density decreased from 2.2 x 10^16 to 1.4 x 10^16 per cubic meter when oxygen flow rate was increased to 100sccm in a 10,000sccm helium flow, while the electron temperature increased from 0.15 to 0.4 eV for the same increase in oxygen flow rate. It was also found that the plasma experiences some streamers and that the streamer?s electron temperature has a wide range between 0.5 to 2 eV. The optimized oxygen flow rate for polymer yarn processing was found to be 40sccm in a 10,000sccm helium flow.
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Moss, Graham James. "A time-dependent collisional-radiative model of low pressure gas discharges." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269399.
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Ruiz, Annia I. "Sample introduction for low pressure microwave induced plasma atomic emission spectrometry." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/30324.
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Yu, Qingsong. "Plasma deposition and treatment by a low temperature cascade arc torch /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9904876.
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Ramakumar, Karthik. "ACTIVE FLOW CONTROL OF LOW PRESSURE TURBINE BLADE SEPARATION USING PLASMA ACTUATORS." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_theses/359.
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The current study examines plasma actuators as flow control devices. The actuators are placed on a turbine blade profile in a 2D turbine cascade for separation flow control. The configuration involves copper strips separated by a layer of dielectric material, across which an AC electric potential in the range of 5 kHz and 5 kV is applied. The efficiency of the actuator is monitored by measuring power input and flow control effectiveness. Preliminary observations are performed for a quiescent case on a flat plate profile to analyze the average and instantaneous velocities generated by the actuator for varied input parameters, such as waveform shape and frequency. Observations include the generation of starting and standing vortices that may be leveraged for unsteady flow control applications. In the case of turbine flow control, the Pratt andamp; Whitney Pak-B blade profile is used to determine the actuator performance for separation reduction at Reynolds number O(104). The results are compared with flow control on and off states for varied actuator input frequency, power, duty cycle and freestream velocity. Pressure measurements are conducted for the actuated case that show reduced separation and increased main flow velocity. Experimental diagnostics include PIV, 7-hole probe, and smoke-wire flow visualization techniques. Phase locked PIV performed at different forcing frequencies reveals the generation of cross-stream vortices providing re-attachment of the separated flow. During the off periods of the cycle the region of separation is observed to creep back to its original separation point. Various fields-of-view show the structure of these cross-stream vortices at different phases. While the actuator is seen to accelerate the flow in the immediate region of the plasma, the generation of starting vortices demonstrates that unsteady actuation is a more effective form of flow control.
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Freeman, Mathieu Jon. "Synthesizing diamond films from low pressure chemical vapor deposition /." Online version of thesis, 1990. http://hdl.handle.net/1850/11262.
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GUPTA, MUNISH. "LOW-PRESSURE AND ATMOSPHERIC PRESSURE PLASMA POLYMERIZED SILICA-LIKE FILMS AS PRIMERS FOR ADHESIVE BONDING OF ALUMINUM." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1187019889.
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Danilov, Vladimir [Verfasser]. "Plasma Modification of Polydimethylsiloxane in a hydrogen CCRF low-pressure discharge / Vladimir Danilov." Greifswald : Universitätsbibliothek Greifswald, 2014. http://d-nb.info/1047137178/34.
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O'Connor, Gavin Thomas. "Development of a low pressure-inductively coupled plasma-ion source for mass spectrometry." Thesis, University of Plymouth, 1998. http://hdl.handle.net/10026.1/1764.
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A low pressure-inductively coupled plasma (LP-ICP) ion source has been investigated for the production of atomic and molecular ions for mass spectrometry (MS). A dedicated LPICP- MS was constructed, by modifying a Hewlett Packard mass selective detector, to detect ions from the LP-ICP. The ion sampling interface and ion optics were designed using established theory and the use of a computer simulation program. Perfluorotributylamine was continuously introduced into the LP-ICP, via a molecular leak, and the ion sampling interface, plasma forward power, and plasma gas flow rates, were optimised. When the LP-ICP ion source was sustained at 6W with a gas flow of 6 ml min'* helium, and iodobenzene and dibromobenzene, introduced via GC, only atomic signals for iodine and bromine were observed. Detection limits were 4 and 76 pg for iodobenzene and dibromobenzene respectively. The addition of nitrogen to a LP helium ICP increased the molecular signal for chlorobenzene, resulting in a detection limit of 2 pg. However, the addition of nitrogen did not aid the production of molecular ions of iodobenzene and dibromobenzene. When 0.07 ml min' of isobuiane was added to the LP-ICP mass spectra similar to those obtained by an electron impact source were observed. However, on the addition of more isobutane only the molecular ions (M*) for chlorobenzene, iodobenzene and dibromobenzene were observed. The detection limits for the instrument operating in the molecular mode were 100, 140 and 229 pg for chlorobenzene, iodobenzene and dibromobenzene respectively. Langmuir probe measurements were used to asses the effect of plasma forward power and gas flow rate on the local plasma potential, ion number density, electron temperature and electron number density within the LP-ICP. The local plasma potential varied from +50 V to -20 V depending on the plasma conditions used. The ion and electron number densities increased with increasing plasma power, with ion number densities of approximately 10^ cm' ^ and electron number densities of approximately at 10* cm ^ The effect of extra plasma gas had a less distinct affect on the plasma excited species. A plasma sustained at 6 W, 7 ml min'' helium and 1.8 ml min'* isobutane was used to provide both quantitative and qualitative information of tetraethyllead in the standard reference friel (NBS SRM 1637 II), with .the determined value of 13.06 ± 0.91 being in good agreement with the certified value of 12.9 ± 0.07 expressed as total lead.
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Lucken, Romain. "Theory and simulation of low-pressure plasma transport phenomena : Application to the PEGASES Thruster." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX046/document.
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Le domaine de la physique des plasmas froids a émergé avec les premières découvertes fondamentales en physique atomique et en physique des plasmas il y a plus d’un siècle. Toutefois, ce domaine a été rapidement orienté vers les applications. L’une des plus importantes dans la première moitié du XXème est le "Calutron" (California University Cyclotron), inventé par E. Lawrence à Berkeley, qui faisait partie du projet Manhattan, et utilisé comme un spectromètre de masse pour séparer les isotopes de l’uranium. Dans un rapport du projet Manhattan daté de 1949, D. Bohm fait deux observations qui sont fondamentales pour la physique des plasmas froids :(i) Les ions doivent avoir une énergie cinétique minimales lorsqu’ils entrent dans la gaine du plasma, estimée à Te/2, Te étant la température électronique.(ii) Le transport du plasma à travers un champ magnétique est augmenté par des instabilités.La propulsion électrique par plasma est utilisée pour des satellites militaires et des sondes spatiales depuis les années 1960 et a suscité un intérêt grandissant ces vingt dernières années avec le développement des applications commerciales des technologies spatiales. Néanmoins, les mêmes questions que celles auxquelles D. Bohm était confronté, c’est-à-dire le transport multidimensionnel, l’interaction plasma-gaine, et les instabilités, se posent toujours. La théorie et les simulations sont d’autant plus importantes pour la conception des systèmes de propulsion électrique que les tests en conditions réelles nécessitent le lancement d’un satellite dans l’espace.Dans ce travail, nous établissons les équations du transport multidimensionnel dans un plasma isotherme, nous proposons un critère de gaine qui permet de rendre compte de la saturation du champ magnétique dans un plasma froid et faiblement ionisé, et nous modélisons le refroidissement des électrons à travers le filtre magnétique du propulseur PEGASES (Plasma Propulsion with Electronegative Gases). Toutes les théories sont motivées et validées par un grand nombre de simulations particulaires PIC bi-dimensionnelles, en utilisant le code LPPic qui a été partiellement développé dans le cadre du projet. Enfin, les cas de simulation sont étendus à une décharge inductive à plasma dans l’iode, avec un nouvel ensemble de section efficaces de réactionThe field of low temperature plasma physics has emerged from the first fundamental discoveries in atom and plasma physics more than a century ago. However, it has soon become very much driven by applications. One of the most important of them in the first half of the XXth century is the "Calutron" (California University Cyclotron) invented by E.~Lawrence in Berkeley, that was part of the Manhattan project, and operated as a mass spectrometer to separate uranium isotopes. In a 1949 report of the Manhattan project, D.~Bohm makes two observations that are fundamental for low-temperature plasma physics.(i) The ions must have minimum kinetic energy when they enter the plasma sheath estimated to T_e/2 , Te being the electron temperature in eV ;(ii) Plasma transport across a magnetic field is enhanced by instabilities.Plasma electric propulsion is used on military satellites and space probes since the 1960s and has gained more and more interest for the last twenty years as space commercial applications were developing. However, the same questions as the ones D.~Bohm was faced with, namely multi-dimensional transport, plasma sheath interaction, and instabilities, arise. Theory and simulation are even more important for electric space propulsion systems design since testing in real conditions involves to launch a satellite into space.In this work, we derive the equations of the multi-dimensional isothermal plasma transport, we establish a sheath criterion that causes the magnetic confinement to saturate in low-temperature, weakly ionized plasmas, and we model the electron cooling through the magnetic filter of the PEGASES (Plasma Propulsion with Electronegative Gases) thruster. All the theories are driven and validated with extensive two-dimensional particle-in-cell (PIC) simulations, using the LPPic code that was partially developed in the frame of this project. Finally, the simulation cases are extended to an iodine inductively coupled plasma (ICP) discharge with a new set of reaction cross sections
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Huang, Chun. "An experimental investigation of low temperature plasma sterilization, treatment, and polymerization processes." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4434.
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Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (April 26, 2007). Vita. Includes bibliographical references.
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Mahony, Charles Michael Oliver. "The development of advanced measurement techniques for the characterisation of low pressure technological processing plasmas." Thesis, University of Ulster, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272339.
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Chartosias, Marios. "Argon-oxygen atmospheric pressure plasma treatment on carbon fiber reinforced polymer for improved bonding." Thesis, California State University, Long Beach, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=1606056.
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Acceptance of Carbon Fiber Reinforced Polymer (CFRP) structures requires a robust surface preparation method with improved process controls capable of ensuring high bond quality. Surface preparation in a production clean room environment prior to applying adhesive for bonding would minimize risk of contamination and reduce cost. Plasma treatment is a robust surface preparation process capable of being applied in a production clean room environment with process parameters that are easily controlled and documented. Repeatable and consistent processing is enabled through the development of a process parameter window utilizing techniques such as Design of Experiments (DOE) tailored to specific adhesive and substrate bonding applications. Insight from respective plasma treatment Original Equipment Manufacturers (OEMs) and screening tests determined critical process factors from non-factors and set the associated factor levels prior to execution of the DOE. Results from mode I Double Cantilever Beam (DCB) testing per ASTM D 5528 [1] standard and DOE statistical analysis software are used to produce a regression model and determine appropriate optimum settings for each factor.
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Rajabian, Mahmoud. "Diagnostic study of low pressure supersonic DC plasma jets by emission spectroscopy and enthalphy probe techniques." Thèse, Université de Sherbrooke, 2001. http://savoirs.usherbrooke.ca/handle/11143/1728.
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In this work, the characteristics of plasma jets produced by a commercial DC plasma spray torch connected to a controlled pressure chamber are investigated. The plasma gas employed is a mixture of argon, nitrogen and hydrogen with the initial gas flow rates of 40, 10, and 1 SLPM respectively. The plasma torch is operated at chamber pressures of 6.5, 13, 26, 39, 53 and 101 kPa and a fixed input power of 17.5 kW. Optical emission spectroscopy is used to measure the temperatures and electron density profiles. The measurements of temperature are carried out by means of a Boltzmann plot of several isolated argon atom spectral lines. The electron density is measured from the Stark broadening of the H[subscript bêta] line 486.1 nm and the continuum emissivity. Partially resolved spectra of the N[subscript 2]+ molecular band are used for the rotational temperature evaluation. The rotational emission from the (0,0) band of the first negative system is compared to synthetic spectra to evaluate the rotational temperature within the flow field. Finally, the measurements of the gas kinetic temperature and the plasma velocity are performed by the enthalpy probe technique. The experimental results show the occurrence and the position of the different gas dynamics zones; i.e., supersonic expansion, stationary shock front and subsonic relaxation at low pressures (less than 40 kPa). The plasma flow is accelerated to its maximum velocity at the expansion where a minimum in the electron density and temperature is observed. At the end of the expansion a stationary shock front occurs at 4, 8, 12, and 15 mm downstream from the nozzle exit at pressures 39, 26, 13 and 6.5 kPa respectively. The electron density profiles show the variations along the plasma axis that coincide with the position of the shock waves. Good agreement between the electron density results obtained from the Stark broadening and from the continuum emissivity is observed. Enthalpy probe measurements on gas kinetic temperature and plasma velocity reveal the general features of low pressure plasma jets, i.e., higher flow velocity and longer heating zone of expanded plasma with lower temperature. The measurements also coincide with the rotational temperature obtained from emission spectroscopy. The temperature results confirm that the local thermodynamic equilibrium LTE exists at pressures of 100 and 53 kPa. However, at lower pressures where the supersonic shock waves are formed, the slow energy exchange between the heavy and light particles leads to significant deviations from the LTE especially in the shock region.
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Navarro, Rodriguez Berta. "Plasma pre-treatment for adhesive bonding of aerospace composite components." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/14669.
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A cold atmospheric pressure plasma source was investigated as an alternative pre-treatment for carbon fibre reinforced epoxy substrates prior to bonding. For reference, common surface pre-treatments were also investigated (peel ply, manual abrasion, and grit blasting). In the aerospace industry, the peel ply, is usually added to one side of the composite surface during manufacture and peeled off prior to bonding. Peel ply can be used independently or in combination with other techniques. The strength of the bonded joints of the different pre-treatments was assessed through tensile lap shear tests. It was found that combining peel ply with plasma increased the joint strength by 10% whereas manual abrasion or grit blasting after peel ply improved the strength of the joints by 15% and 20% respectively. The effect of pre-treating the composite substrate side without peel ply (bag side) was also investigated. The strength of the joints produced without any pre-treatment was increased by 99% for manual abrasion, 134% for grit blasting and by 146% for plasma. Comparing both surfaces of the composite substrates, it was found that using peel ply improved the performance of the joints by 91%. In order to understand better the effects of the different pre-treatments, surface characterisation of the substrates (surface roughness, surface free energy, and analysis of chemical changes) was also conducted. The effect of roughness did little to affect the strength values (for both surfaces of the composite). The adhesive used in this research was very good at wetting the surface, regardless of the roughness. However, when the adhesive was able to wet the surface, the relationship between bond strength and surface free energy was unclear. Plasma was shown to increase levels of oxygen at the surface and reduce/eliminate the concentration of fluorine at the surface on the bag side of the composite.
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Yonson, Sara. "Cell treatment and surface functionalization using the atmospheric pressure glow discharge plasma torch (APGD-t)." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99551.
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The atmospheric pressure glow discharge plasma torch (APGD-t ) was used to treat cell cultures to investigate potential reactions with biological tissue. The plasma jet successfully detached HAAE-1 and HepG2 cells from a culture surface. The cells surrounding the void did not show any morphological damage after treatment. The detached HepG2 cells were transplanted to a new vessel, where they reattached. A viability assay showed the transplanted cells had functioning mitochondria up to 7 days after exposure to the plasma jet. These cells were also shown to have a permeabilized cell membrane for 4 hours after treatment, with resealing of the cell membrane occurring within 24 hours of transplantation. This work could be useful for localized tissue removal, and the injection of foreign DNA and RNA into cells for gene therapy.In separate experiments, sterilized bacterial grade polystyrene (BGPS) was functionalized with the plasma jet to improve cell adhesion. The contact angle of treated BGPS decreased from 93° to 35°, likely due to the addition of polar oxygen and nitrogen groups to the surface. The width of the functionalized track was visualized using the adhesion of HAAE-1 cell cultures, and was found to correspond to approximately double the diameter of the plasma jet. Direct plasma micropatterning using the APGD-t could replace the masks and chemicals required in present photolithographic techniquesIn separate experiments, sterilized bacterial grade polystyrene (BGPS) was functionalized with the plasma jet to improve cell adhesion. The contact angle of treated BGPS decreased from 93° to 35°, likely due to the addition of polar oxygen and nitrogen groups to the surface. The width of the functionalized track was visualized using the adhesion of HAAE-1 cell cultures, and was found to correspond to approximately double the diameter of the plasma jet. Direct plasma micropatterning using the APGD-t could replace the masks and chemicals required in present photolithographic techniques.
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Wolkenhauer, Arndt. "Plasma treatment of wood and wood-based materials by dielectric barrier discharge at atmospheric pressure /." Göttingen : Sierke, 2009. http://d-nb.info/993076556/04.
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Child, David Alan. "Investigation of a hollow cathode plasma source for assisted low pressure deposition of thin films." Thesis, University of the West of Scotland, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.732974.
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Marcelli, Giacomo. "Development of a plasma gun device with multijet array for treatment of liquids." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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The aim of the present work is the development of a non-equilibrium atmospheric pressure plasma multijet device for the treatment of liquids. The interest in plasma multijet device is due to the potentiality for scaling up of plasma jet applications, since such device allows for treatment of higher volume of liquid than single-jet system. The multijet device has been developed in the laboratories of GREMI (Groupe de Recherches sur l’Energétique des Milieux Ionisés) at Orléans, and afterward tested for liquid decontamination in the “Tesla Plasma Research lab” laboratories of the group for Industrial Applications of Plasmas at the Alma Mater Studiorum - Università di Bologna. A versatile multijet device, able to work both in ambient air with jets impinging on a liquid target or in underliquid condition, with plasma discharge formation in bubbles flushed inside the liquid has been realized. Different liquids have been exposed to the plasma investigating the change in pH value, conductivity, temperature and reactive species concentration induced in liquid after plasma treatment. Afterward, electrical characterization has been performed by means of voltage and current probes in order to evaluate the power consumption. Finally, decontamination activity of the plasma treatment has been investigated using a liquid solution inoculated with Escherichia coli revealing antibacterial efficacy.
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Meige, Albert, and albert@meige net. "Numerical modeling of low-pressure plasmas: applications to electric double layers." The Australian National University. Research School of Physical Sciences and Engineering, 2006. http://thesis.anu.edu.au./public/adt-ANU20070111.002333.
Full textAbstract:
Inductive plasmas are simulated by using a one-dimensional particle-in-cell simulation including Monte Carlo collision techniques (pic/mcc). To model inductive heating, a non-uniform radio-frequency (rf) electric field, perpendicular to the electron motion is included into the classical particle-in-cell scheme. The inductive plasma pic simulation is used to confirm recent experimental results that electric double layers can form in current-free plasmas. These results differ from previous experimental or simulation systems where the double layers are driven by a current or by imposed potential differences. The formation of a super-sonic ion beam, resulting from the ions accelerated through the potential drop of the double layer and predicted by the pic simulation is confirmed with nonperturbative laser-induced fluorescence measurements of ion flow. It is shown that at low pressure, where the electron mean free path is of the order of, or greater than the system length, the electron energy distribution function (eedf) is close to Maxwellian, except for its tail which is depleted at energies higher than the plasma potential. Evidence supporting that this depletion is mostly due to the high-energy electrons escaping to the walls is given.
¶
A new hybrid simulation scheme (particle ions and Boltzmann/particle electrons), accounting for non-Maxwellian eedf and self-consistently simulating low-pressure high-density plasmas at low computational cost is proposed. Results obtained with the improved hybrid model are in much better agreement with the full pic simulation than the classical non self-consistent hybrid model. This model is used to simulate electronegative plasmas and to provide evidence supporting the fact that propagating double layers may spontaneously form in electronegative plasmas. It is shown that critical parameters of the simulation were very much aligned with critical parameters of the experiment.
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Calvo, Jesús, Philipp Steinke, Marcus Wislicenus, Lukas Gerlich, Robert Seidel, Ellen Clauss, and Benjamin Uhlig. "Organosilane Downstream Plasma On Ultra Low-k Dielectrics: Comparing Repair With Post Etch Treatment." Universitätsbibliothek Chemnitz, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-207098.
Full textAbstract:
Plasma induced damage of ultra low-k (ULK) dielectrics is a common phenomenon in BEOL interconnects. The damage leads to an increase in k-value, which raises the RC delay, leading to increased power consumption and cross talk noise. Therefore, diverse repair and post etch treatments (PET) have been proposed to restore or reduce the ULK damage. However, current repair processes are usually based on non-plasma silylation, which suffers from limited chemistry diffusion into the ULK. Moreover, the conventional PET based on anisotropic plasma results in bottom vs. sidewall inhomogeneities of the structures (e.g. via and trench). To reduce these drawbacks, an organosilane downstream -plasma (DSP) was applied. This new application resulted in an increased resistance to ULK removal by fluorinated wet clean chemistries, preserving the ULK hydrophobicity, keeping its carbon content relatively high. The effective RC measured on 28 nm node patterned wafers treated with a DSP PET remains nevertheless comparable to the process of record (POR).
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Rutherford, David Colin Ernest. "Atmospheric-pressure plasma-droplet treatment system : focus on aerosolised bacteria and remote delivery of reactive species." Thesis, Ulster University, 2017. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.734604.
Full textAbstract:
This thesis presents an experimental study of a novel non-thermal atmospheric-pressure gas plasma with controlled liquid droplet flow as an efficient source of reactive species that can influence fundamental chemistries in many applications. The electrical discharge is ignited within the confined geometry of a cylindrical quartz tube that allowed for small liquid droplets entrained in the gas flow to pass through the plasma region only once. Neon was used to generate the droplets from deionised water or a buffered solution and additional helium transported the droplets from the nebuliser through the plasma. A diffuse, glow-like discharge formed that remained ignited during droplet transport. Droplets that enter the plasma contribute to the formation of reactive species and survive the treatment without complete evaporation. This observation paved the way for attempts to expose bacteria-loaded droplets to the same treatment. When collected in the presence of a hydrogen peroxide scavenger, plasma treatment did not affect cell viability or growth kinetics. A biomarker of lipid peroxidation was detected, suggesting cell interaction with plasma-generated species delivered into the droplet over short timescales i.e. droplet transit time through the plasma region. Due to the omission of oxygen and nitrogen from the plasma, a vast proportion of RONS that are reported in the plasma-liquid literature cannot be generated, therefore simplifying the chemistry. Hydroxyl radical is thought to feature in the onset of cellular oxidative stress and the species is known to be generated from plasma-liquid interactions. The radical was detected in both the gas and liquid phases from the plasma treatment of droplets and remained chemically active far from the core plasma region. Hydrogen peroxide is a well-known biocide generated from plasma-liquid interactions and was detected in the plasma-treated droplet collection liquid. These results suggest the new technique can remotely apply reactive species contained in plasma-activated droplets or bulk liquid to a target that never comes in direct contact with the plasma itself. This has the potential to be able to influence biological systems in a controlled way by fine-tuning the chemistry generated from the interaction between non-equilibrium plasma and low volume liquid droplets.
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Raguse, Marina [Verfasser], Franz [Gutachter] Narberhaus, and Peter [Gutachter] Awakowicz. "Bacillus subtilis spore resistance towards low pressure plasma sterilization / Marina Raguse ; Gutachter: Franz Narberhaus, Peter Awakowicz." Bochum : Ruhr-Universität Bochum, 2017. http://d-nb.info/1140222899/34.
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Ujang, Zaini Bin. "Treatment and reclamation of heavy metals in electroplating wastewater using low pressure reverse osmosis membranes." Thesis, University of Newcastle Upon Tyne, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309830.
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Bhatt, Sudhir. "Nanometric thick copolymers elaborated by low and atmospheric pressure non-equilibrium plasmas for biomedical applications." Paris 6, 2013. http://www.theses.fr/2013PA066415.
Full textAbstract:
The research described in this doctoral thesis work was mainly focused towards the low pressure inductively excited PECVD of organic precursors for biomaterials. An open air atmospheric pressure DBD plasma jet was also studied for the antifouling applications. Systematic studies were carried out in order to optimize the deposition of plasma polymerized (PP) coatings which were deposited at different process parameters for biomedical applications. The optimized amphiphilic PFDA-DEGVE coatings, presented no adhesion with respect to BSA as well as Lysozyme proteins. The plasma processing parameters were optimized using DoE methodology. By adjusting the process parameters, the chemical compositions of the PCL- PEG coatings were tailored to be cell adherent, convenient for biomedical implants such as artificial skin substrates, or cell repellent which could be used for antibiofouling surfaces for urethral catheters, stents etc. Multilayer biodegradable coatings based on PCL- PEG polymers were successfully used for controlled delivery of anticancer drug and tested in vitro. PP Poly (2-ethyl 2-oxazoline), having a peptidomimetic structure was deposited by LP. Such polymers are considered to be a prime candidate for an alternative of PEG like surfaces for antibiofouling applications. The last chapter was devoted to open air AP argon plasma jet. The deposited PEG coatings had 56. 3% of ether functions and were cell repellent as compared to a positive control (PS). This study has shown the capability of plasma processes for the deposition of (co-) polymer coatings with tailorable surface chemical compositions, with considerable promises for the variety of biomedical applicationsLes recherches effectuées dans cette thèse se concentrent essentiellement sur la PECVD par plasma basse pression à partir de précurseurs organiques pour la synthèse de biomatériaux. Un procédé à jet de plasma hors équilibre à couplage DBD a aussi été développé pour élaborer des surfaces anti-bioadhésives. Les conditions opératoires ont été optimisées afin de pouvoir répondre à plusieurs applications biomédicales. Des copolymères amphiphiles à base de PFDA-PEG, élaborés et optimisés par des plans d’expériences, n’ont montré aucune adhésion vis à vis des protéines BSA et Lysozyme. Les polymères PCL-PEG ont aussi été étudiés, et les différentes compositions ont permis d’obtenir soit de bonnes propriétés d’adhésion cellulaire, permettant ainsi d’envisager des applications en ingénierie tissulaire, soit des surfaces anti-bioadhésives, intéressantes pour élaborer des cathéters ou des stents. Les copolymères PCL-PEG déposés en multicouches ont permis de contrôler les cinétiques de relargage de médicaments et de réaliser des tests in vitro. Nous avons aussi travaillé sur le remplacement des PEG en déposant un polymère mimant la structure des peptides ; le polyoxazoline. Les résultats obtenus ont donné de bonnes propriétés anti-fouling. Enfin, des surfaces anti-bioadhésives ont été élaborées par PECVD à pression atmosphérique. Les résultats obtenus ont montré une rétention des fonctions éthers de 56. 3% et les surfaces correspondantes repoussent les cellules. En conclusion, les travaux menés au cours de cette thèse ont montré que les procédés plasma permettent de déposer des (co)polymères permettant de répondre à une large palette d’applications dans le domaine biomédical
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Liu, Bo. "Non-thermal atmospheric pressure plasma interacting with water for biological applications." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLX049/document.
Full textAbstract:
Les plasmas froids produits par les décharges électriques sont des gaz faiblement ionisés, ce qui maintient la température du gaz à une température proche de la température ambiante, contrairement à la température de l'électron qui peut atteindre plusieurs électron-volts. Les applications des plasmas froids en médecine et en agriculture sont des nouveaux domaines de recherche multidisciplinaires basés sur les interactions de ces plasmas avec des organismes vivants. Le champ électrique ainsi que les espèces réactives de l’oxygène et de l'azote peuvent inactiver les bactéries, stimuler la régénération de la peau (dermatologie), la réduction tumorale (oncologie) et la germination des graines (agriculture). Ces nouveaux domaines de recherche, basé sur la chimie produite par l’interaction plasma-liquide est très prometteur et se développe rapidement. L’objectif de ce travail est d’étudier les interactions entre les plasmas froids et l’eau pour les applications biologiques, d’une part la promotion de la germination des graines au moyen d’une décharge à barrière diélectrique (DBD) et, d’autre part, l’effet ex vivo d’un traitement par jet de plasma froid sur la peau.Ce manuscrit est divisé en cinq chapitres: i) On présente tout d'abord une revue de la littérature présentant l'état de l’art concernant l'interaction plasma-liquide et les principales avancées en matière d'applications des plasmas froids à la germination des semences. Ii) Deuxièmement, les dispisitifs expérimentaux sont décrits, en particulier la fabrication de réacteurs à plasma utilisant l’impression 3D. Iii) Ensuite, la production d'espèces réactives gazeuses et aqueuses formées par des plasmas de type DBD a été mesurée quantitativement et l'interaction plasma-liquide a été analysée. Iv) Puis, plusieurs variétés de graines ont été sélectionnées pour évaluer l’effet un traitement par plasma DBD ; l'étude des mécanismes de promotion de la germination du plasma a été spécifiquement étudiée en traitant les graines de soja vert dans différentes conditions de décharge, dans différents milieux, avec un champ électrique seul et dans différentes conditions de cultures ou de niveau d'hydratation des graines.v) Enfin, l'imagerie paramétrique de Muller (MPI) a été appliquée pour la modification de la peau de souris ex vivo traitées par un plasma à jet d'héliumNon-Thermal-Plasmas (NTP) produced by electric discharges are weakly ionized gases, which keeps the gas temperature at near room temperature contrary to the electron temperature which can reach several electron-Volts. Applications of NTP to medicine and agriculture are new multidisciplinary research fields based on interactions of the Non-Thermal-Plasmas with living organisms. Electric field as well as Reactive Oxygen and Nitrogen Species produced by NTP may inactivate bacteria, stimulate skin regeneration (dermatology), tumor reduction (oncology) and seeds germination (agriculture). These new fields of research are based on the plasma-liquid chemistry. The objective of this work is to study the NTP interacting with water for biological applications including on one hand, the promotion of the germination of seeds using a Dielectric Barrier Discharge (DBD) and on the other hand, the effect of a plasma jet treatment ex vivo on skinThis manuscript is divided in five chapters: i) First a literature review is presented showing the state of the art of the plasma-liquid interaction, and the main advances of the application of non thermal plasmas to seed germination. Ii) Second, experimental set ups are described, in particular the manufacturing of plasma reactors using 3D printing. Iii) then , the production of gaseous and aqueous reactive species formed by DBD plasmas was measured quantitatively and plasma-liquid interaction was analyzed. Iv) Next, different varieties of seeds were selected to evaluate the effect of a DBD plasma treatment and the study of the mechanisms of plasma germination promotion was specifically investigated by treating mung bean seeds in different discharge conditions, in different mediums, in electric field alone and in different hydration levels of seeds.v) Finally, Muller parametric imaging (MPI) was applied to study the modification of ex vivo mice skin treated by a helium jet plasma
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Nilsen, Kyle. "Development of low pressure filter testing vessel and analysis of electrospun nanofiber membranes for water treatment." Thesis, Wichita State University, 2011. http://hdl.handle.net/10057/3997.
Full textAbstract:
Polymeric electrospun nanofibrous membranes were investigated for use in water filtration applications. A customized pressure vessel was designed according to the American
Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) to be used to test the membrane for its filtration properties. Low pressure filtration was focused on due to
previous research that suggested that high pressure water testing of electrospun polymeric
nanofibrous filters could decrease the filtration capability by expanding the pore size within the
membrane. During testing it was found that this technology does reduce pathogens but will only
remove a portion of them per pass, and thus is not adequate for use as a one pass pathogenic
filter. The filter was found to be well suited for the reduction in the amount of suspended and
dissolved solids, increasing clarity, and reduction of odor. A scanning electron microscope
(SEM) was used to study the electrospun fibrous pads to narrow down on an ideal parameter set
that gave the desirable characteristics for the application of filtration. The composition of the polymer, and electrospinning parameters, were also manipulated to give a hydrophilic, or
absorbent, membrane to facilitate a low pressure differential for filtration. It was demonstrated
that this type of filtration membrane can be manufactured inexpensively while not requiring
electricity or other external power source to generate large pressure differentials and flow. This
is desirable because it allows this technology to be used in areas where both basic utilities and
clean water are limited, for example in remote Africa and India. It was also shown that this filter
has benefits over best selling commercial water filters currently on the market. This technology
may be best suited for enhancement of tap water where healthier and cleaner water is desired.
Pre-filtration of reverses osmosis (RO) or other ultrafine filter system, to increase the life of the
primary filter while decreasing fouling and maintenance may be another application.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
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Thomson, M. "The modification of thin film surface structure via low temperature atmospheric pressure CVD post process treatment." Thesis, University of Salford, 2013. http://usir.salford.ac.uk/30694/.
Full textAbstract:
In photovoltaic thin film cells, a transparent conducting oxide (TCO) layer is required to transport current. The most common TCOs used are F:SnO2 (fluorine doped tin oxide), ZnO (zinc oxide) and ITO (indium doped tin oxide). ZnO is normally deposited in a vacuum based process, sputtering or low pressure chemical vapour deposition (LPCVD). Atmospheric pressure chemical vapour deposition (APCVD) is an attractive alternative for ZnO deposition. A critical parameter for TCOs in photovoltaic thin films is the surface morphology which defines the optical scattering properties. The ability to control the spectral sensitivity and degree of scattering are both important process parameters for high performance cells. This thesis investigates APCVD for film growth of ZnO plus dopants (fluorine and aluminium), and the effects of atmospheric pressure plasma etching of ZnO and F:SnO2. ZnO was deposited in multiple system geometries all based on thermal activated CVD. The oxidant source purity is shown to be critical for stable growth at higher temperatures required for dopant incorporation. A fundamental problem was encountered with fluorine doping, whereby the films would crack beyond a critical thickness. A solution was found with the development of a F:SnO2 and F:ZnO composite stack. Photovoltaic testing of this hybrid TCO was encouraging, showing the potential benefit of the composite structure. Modification of the surface morphology was achieved by atmospheric pressure plasma, based on a dielectric barrier discharge configuration. This novel system enables the etching of TCO films without the introduction of hazardous wet chemistry. In this thesis the effects of etching regime and feedgas composition are studied and an etching mechanism is proposed. Isolation of the etching environment enabled investigation into the feed gas mixture, demonstrating which were critical for etching. Both materials showed a dependence on the feed gas mixture for etching, with F:SnO2 requiring HCl and O2 and H2O for ZnO.
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Bach, Markus. "Fundamental Analysis of the Interaction of Low Pressure Plasmas with Polymer Surfaces." Doctoral thesis, 2003. https://repositorium.ub.uni-osnabrueck.de/handle/urn:nbn:de:gbv:700-2003112531.
Full textAbstract:
The treatment of polymer surfaces by low pressure plasmas is of technological interest in a variety of applications for modification and functionalisation. Until now the interactions of the individual plasma species (especially electrons) with polymeric material have not been subject of a microscopic study.In an anticipated chapter the inner plasma parameters were characterised by Langmuir probe measurements, leading to a precise knowledge about the density and energy distributions of plasma electrons and ions. The values for electrons were later used for an exclusive treatment with this species. The main part of this thesis describes and interprets the chemical composition after UV, plasma and electron treatment by x-ray photoelectron spectroscopy (XPS), structural changes by atomic force microscopy (AFM) and their combination to distinguish the fundamental interactions with polyethylene and polypropylene surfaces. It was found that all treatments show specific modification behaviour according to the chemical composition, topography and modification depth. For an argon microwave discharge, the plasma effects can also be obtained by a combination of UV and electron treatment. Fundamental radical reactions have been traced indirectly by chemical derivatisation as well as their passivation reactions through cross-linkage and the creation of double bonds.
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Chen, Yong-Chih, and 陳勇志. "Study of Novel Low Temperature Atmospheric Pressure Plasma System Design and Influences of Surface Treatment on Photo-Resistances and Polyimide." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/75955932300426995872.
Full textAbstract:
碩士義守大學
材料科學與工程學系碩士班
94
Plasma operation at low temperature and atmospheric pressure (AP) is an interesting and candidate replacement of other surface treatment methods (e.g. low-pressure plasma or wet chemical treatments) for relatively low costs, in-line process capabilities, acceptable to treat substrates of large areas and various geometrical shapes, and maintaining the reasonable material characteristics. This study was basically divided into two stages. In the first stage, we had successfully self-designed and manufactured novel parallel-tube and plasma-jet types low temperature atmospheric pressure plasma electrodes. Alternating voltage (AC) generators with sinusoidal and pulsed types at voltage of 10 KV and frequency of 20~30 KHz were used to form AP plasma. Plasma ignition occurred by flowing clean dry air (CDA) and the treated substrates located on a speed-controlled holder at the speeds of 0-10.0 cm/s. In the second stage, investigated the effects of combining two kinds of novel electrodes and AC generators on the organic materials of photo-resistance and polyimide surface treatment, and studied these films surface characteristics variations, including removal rate, discharging phenomena, roughness, surface energy and chemical bonding variations with AP treatment time, to obtain optimal hardware combination. Ellipsometer, small-size (50 mm x 70 mm) liquid crystal display (LCD), atomic force microscopy, contact angle analyzer, scanning electron microscopy were used to analyze PR and PI films removal rate, discharging phenomena, surface roughness, surface energy and morphology. Fourier transform infrared and x-ray photoelectron spectroscopy were also used to identify chemical bonds variations. The atmospheric plasma system by flowing clean dry air consisted of plasma jet electrode and pulsed type AC generator exhibited reasonable organic material removal ability, no discharging phenomena, more surface energy and polar functional groups, and was recommended to be adopted for these polymers removal and surface treatment.
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PEKÁREK, Michal. "Optimalizace depozičních parametrů za účelem vytvoření fotokatalytických titanoxidových vrstev metodou PECVD." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-153375.
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This thesis presents Photocatalytic TiOx layers created by own PECVD reactor assembled in the building of Department of Applied Physics and Technics. Parameters of depositions were optimalized as well as the PECVD reactor itself. Final layers are compared to layers made by Degussa P25. As a result based on the included measurements, this thesis tries to answer the question whether PECVD is the suitable method for depositions of photocatalytic layers.
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Cyue, Jhong-Hong, and 闕仲宏. "Improvements of Amorphous Si-Alloy Based Thin-Film Solar Cells with H2/O2- Plasma Treatments on Transparent Electrode and Deposition of i-a-SiGe:H Light Absorption Layer at Low Pressure." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/bdbr48.
Full textAbstract:
碩士國立中央大學
電機工程研究所
96
In this thesis, the H2/O2-plasma treatments on transparent indium-tin-oxide (ITO) electrode and deposition of i-a-SiGe:H absorption layer at low pressure have been used to improve the performance of amorphous Si-alloy based thin-film solar cells. Firstly, since that the series resistance between the ITO electrode and amorphous layer plays an important role in the performance of a solar cell, the in-situ plasma treatments was employed to improve the contact and it was found that the performance of a p-i-n a-Si:H thin-film solar cell could be enhanced with the H2-plasma (100 W, 0.4 torr, 25 ℃ and 5 min.) and then O2-plasma (55 W, 0.15 torr, 25 ℃ and 5min.) treatments on ITO electrode. This was due to the combination of H2- and O2-plasma treatments could remove the hydrocarbon compounds and increase the work function of ITO electrode. Hence, the Schottky barrier height between the ITO and amorphous layer could be lowered. In addition, the i-a-SiGe:H absorption layer was deposited at a lower pressure of around 0.25 torr with a plasma-enhanced chemical vapor deposition system, to reduce the amount of Si=H2 bonds in the film and hence improve the performance of graded ITO/p-SiC:H/buffer layer (i-a-SiC:H)/i-a-Si:H/interface layer/i-a-SiGe:H/n-a-Si:H/Al solar cell. In this study, the highest obtainable conversion efficiency of this graded solar cell was 3.63 %.
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Κεφάλα, Ειρήνη. "Επεξεργασία υλικών από ψυχρό πλάσμα φθορανθράκων προς παραγωγή μη-ρυπαινόμενων μονωτικών υλικών." Thesis, 2013. http://hdl.handle.net/10889/6011.
Full textAbstract:
Η μείωση της ρύπανσης των μονωτήρων εξωτερικών χώρων είναι ένα αντικείμενο το οποίο έχει απασχολήσει εκτεταμένα τους μηχανικούς λόγω των απαιτήσεων που υπάρχουν στην αποδοτική λειτουργία των μονωτήρων αυτών.
Στην παρούσα διπλωματική δοκιμάστηκαν τέσσερα διαφορετικά υλικά (δυο πολυμερή και δυο κεραμικά) που χρησιμοποιούνται στην κατασκευή τέτοιων μονωτήρων και μελετήθηκε η μεταβολή στην υδροφοβία της επιφάνειάς τους μετά από επεξεργασία αυτών από ψυχρό πλάσμα φθορανθράκων χαμηλής πίεσης. Παράλληλα έγιναν και ηλεκτρικές μετρήσεις σε πλάσμα Ο2 και CF4 προκειμένου να γίνουν γνωστές οι τιμές της τάσης και του ρεύματος κάτω από τις οποίες έγινε η επεξεργασία των επιφανειών.
Πιο συγκεκριμένα:
• Στο πρώτο κεφάλαιο έγινε μια εισαγωγή στους μονωτήρες εξωτερικών χώρων, κατάταξη αυτών με βάση τη θέση τους ως προς τους ηλεκτροφόρους αγωγούς αλλά και ως προς το υλικό κατασκευής τους. Έγινε επίσης παρουσίαση των επιπτώσεων της ρύπανσης των μονωτήρων αλλά και απαρίθμηση των μεθόδων αντιμετώπισης της. Τέλος, εξηγήθηκε η έννοια της υδροφοβίας και έγινε εισαγωγή στις ιδιότητες του πλάσματος φθορανθράκων.
• Στο δεύτερο κεφάλαιο περιγράφηκε αναλυτικά η διάταξη παραγωγής πλάσματος χαμηλής πίεσης καθώς επίσης και η διάταξη μέτρησης γωνιών επαφής. Παρατίθενται φωτογραφίες αλλά και πλήρης περιγραφή όλων των επιμέρους διατάξεων που χρησιμοποιήθηκαν στην παρούσα διπλωματική εργασία.
• Στο τρίτο κεφάλαιο παρουσιάστηκαν και αναλύθηκαν τα πειραματικά αποτελέσματα και μετρήσεις (ηλεκτρικές μετρήσεις και μετρήσεις γωνιών επαφής) που συλλέχθηκαν κατά την εκπόνηση της εργασία καθώς επίσης και γραφικές παραστάσεις για την ομαδοποίηση των δεδομένων.
• Στο τέταρτο κεφάλαιο καταγράφηκαν τα συμπεράσματα στα οποία οδήγησε η παρούσα διπλωματική.Reducing pollution in the surface of outdoor insulators is an issue that has occurred and has troubled lots of engineers due to strict requirements that should be met for specific insulators’ proper operation. In the present thesis, four different insulating materials (two polymerics and two ceramics) were tested and the change on their surface hydrophobic properties was studied. Furthermore, electrical measurements in O2 and CF4 plasma were taken so the values of the current and voltage under which this experiment has taken place, would be known. More specific: • In the first chapter, an introduction to outdoor insulators was made. They were classified according to their position regarding the conductors and their construction material. Also, the consequences of pollution and some ways of its control were presented. Lastly, there was explained the concept of hydrophobicity and the properties of fluorocarbon plasma. • In the second chapter, the vacuum system that was used to create low pressure, fluorocarbon plasma is analyzed as well as the device for measuring the contact angles of the samples. This detailed presentation is accompanied by photographs and full analysis of all the individual devices that were used in the present thesis. • In the third chapter, all the experimental results were presented and analyzed. The measurements (electrical and contact angles’) were plotted so that data would appear in groups. • In the forth chapter, all the conclusions of the present thesis were exported.
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Jian-HongYang and 楊建鴻. "Development of Low Pressure Magnetized DBD Plasma Source." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/uhn459.
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碩士國立成功大學
太空與電漿科學研究所
107
Conventional dielectric barrier discharges (DBDs) are one type of atmospheric pressure plasmas produced between two ac-biased electrodes covered with dielectric material. DBDs have been used in various purposes such as a source of reactive fields, etching of wafer, removal of skin scars, and so on. For these applications, DBDs are typically operated at atmospheric pressure. This study aims at development of a new DBD-based plasma source for magnetized plasma experiment (MPX). We developed a low pressure-magnetized DBD plasma source using an inverter circuit and a glass tube with a jet configuration for MPX. The external magnetic field was applied in the axial direction of the glass tube. Mechanism of plasma production by the DBD source were experimentally investigated. From the argon DBD experiments, the followings are clarified: 1.Features of conventional atmospheric pressure DBDs were observed at low pressure (~ mTorr) with the use of low frequency voltage source (800 Hz, 1.5 kV). 2.With high frequency voltage source (48 kHz, 0.5 kV) using an inverter circuit, two distinct discharge states were identified: One is DBD-like plasma state, which is characterized by a spikey waveform of the electrode current, high electron density at the jet region, and high absorption of injected power inside the glass tube. The other is CCP-like plasma state characterized by a sawtooth waveform of the electrode current, low electron density at the jet region, and low absorption of injected power inside the glass tube. The DBD-like plasma states were realized at high gas flow rate (~ 80 – 100 sccm) and lower magnetic field strength than a threshold. The CCP-like plasma states were produced at low gas flow rate and higher magnetic field strength than the threshold. 3.A simple model is proposed for the explanation of the transition between DBD-like plasma and CCP-like plasma states. The model explains the transition phenomenon by change of distance between the virtual capacitor electrodes. In the case of the weak magnetic field, power electrode and the neighboring grounding electrode constitutes a capacitor like conventional DBD plasma jet. In the case of the strong magnetic field, the power electrode and the distant grounding grid (i.e. the vacuum chamber) constitutes a capacitor. 4.The achieved DBD plasma density at the confinement region of the MPX device was on the order of 1013 m ^(-3). The plasma diameter and length of the plasma jet were 4 cm and 150 cm, respectively. These parameters were obtained in the CCP-like plasma states. Further investigation of the plasma production mechanisms including associated atomic process, helium discharge etc. are needed. Key words: Atmospheric pressure DBDs, plasma sources, charge memory effect, magnetized plasma, Langmuir probe theory
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Ho, Wesley, and 何憾. "Study of Atmospheric Pressure Plasma Surface Treatment for ITO Glass." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/29994931826487852809.
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碩士義守大學
材料科學與工程學系碩士班
95
Recently, the research and development of atmospheric pressure (AP) low-temperature plasma have become very important in the world, and there’re also many practical applications in various industries, especially for the electrical industry. Due to the manufacturing processes of the electrical industry pursues advanced techniques and low cost considerations, results in the AP plasma technology to be the candidate for surface treatment process. The study mainly focused to investigate the characteristics of ITO glass surface treatment with AP plasma system. Because LCD industry is supported and encouraged by government, so that the novel material technology development is also important and urgent. In this study, we choose the ITO and quartz glasses surface treatment to be the major research direction and adopt AP plasma system with in-line platform, corona electrode, clean dry air (CDA) and H2/Ar mixture process gases to study the characteristics variations of surface treatment. During the experimental period, we suggested to use the CDA as the plasma gas source for its extra low cost and convenience. The results indicated that the substrates treated by AP plasma system with CDA and H2/Ar mixture process gases, the treated rates of 20mm/s, resulted in great clean efficiency on ITO glasses surface. Except those, we also found the ITO glasses characteristics variations by surface treatment with AP plasma system depend on the treated gases, the power supply system, the electrode design and the initial characteristics of ITO glasses. These evolutional characteristics may also be referred to the other applications and development of ITO glasses.
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Huang, Junhui. "Separation control over low pressure turbine blades using plasma actuators." 2005. http://etd.nd.edu/ETD-db/theses/available/etd-04152005-095454/.
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Thesis (Ph. D.)--University of Notre Dame, 2005.Thesis directed by Thomas C. Corke for the Department of Aerospace and Mechanical Engineering. "April 2005." Includes bibliographical references (leaves 176-180).
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Scheubert, Peter [Verfasser]. "Modelling and diagnostics of low pressure plasma discharges / Peter Scheubert." 2002. http://d-nb.info/966327535/34.
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HUANG, YU-YA, and 黃郁雅. "Study for Microbial Decontamination Using Low Temperature Atmospheric Pressure Plasma." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/3yrfwf.
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Liu, Pei-Chien, and 劉沛謙. "Comparison of Atmospheric-pressure Plasma Treatment and Ultraviolet Induced Treatment in Modified PP Membranes." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/n3ttdr.
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碩士中原大學
化學工程研究所
103
In this research, we compared the atmospheric-pressure dielectric barrier discharge (APDBD) plasma grafting with the UV-induced grafting in the surface modification of membranes. Sulfobetaine (SBMA) was grafted from the polypropylene membrane (PP) in order to reduce bio-fouling. The functional groups of the monomer SBMA are positive charge (N+(CH3)3) and negative charge (SO3-). The chemical composition and surface morphology of the modified PP membranes were characterized by FTIR-ATR, SEM, and XPS. In addition, the anti-biofouling capabilities of preparing membranes were characterized by the protein adsorption of bovine serum albumin (BSA) and lysozyme (LY). The antibacterial property was tested via attachment ability with Escherichia coli. Finally, cyclic filtration test was done in BSA solution for bio-separation application. Moreover, to investigate whether the main factor of plasma grafting was reactive species or UV radiation from plasma, we covered the membrane with quartz plate to inhibit the reaction between reactive plasma species with membrane and discussed the effect of UV from plasma to the grafting of SBMA on PP. Both methods, UV treatment at 60 min and APDBD treatment at 90s, showed significant anti-biofouling capability. The PP-g-SBMA membranes by UV treatment and APDBD were found to effectively resist protein adsorption and exhibit a very low bio-fouling characteristic during cyclic-filtration. Flux recovery of water (FRwi) in UV treated and APDBD treated are 88.7% and 87.3%, respectively.
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Huang, Chen-Feng, and 黃哲楓. "The Study of Polycarbonate Surface Treatment by Atmospheric Pressure Plasma Jet." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/28804515301138507241.
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