Дисертації з теми "Atmospheric plasma applications"
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Shapoval, Volodymyr. "Atmospheric plasma processes for environmental applications." Doctoral thesis, Università degli studi di Padova, 2012. http://hdl.handle.net/11577/3423420.
Повний текст джерелаLa chimica dei plasmi è un settore in rapida espansione che conta un gran numero di applicazioni, dal trattamento di materiali, inclusi materiali biologici, alla decomposizione di inquinanti e produzione di energia. Il cosiddetto plasma atmosferico, prodotto da scariche elettriche corona o a barriera di dielettrico in un gas a pressione atmosferica, è particolarmente attraente grazie ai costi contenuti e alla facilità di impiego e manutenzione. L’elevata concentrazione di specie ad alta energia chimicamente attive (ad esempio elettroni, ioni, atomi, radicali, specie eccitate, fotoni) presenti in questi plasmi può promuovere reazioni chimiche che in condizioni più blande sarebbero difficilmente realizzabili. La Tesi riguarda l’impiego del plasma atmosferico per attivare due diversi processi: la purificazione dell’acqua da inquinanti organici e il reforming di metano con anidride carbonica per produrre gas di sintesi. Entrambi i processi mirano a dare un contributo nella risoluzione di un problema ambientale, la crescente domanda di acqua potabile in un caso, la necessità di limitare le emissioni di carbonio nell’atmosfera nell’altro. A causa della natura molto diversa dei due processi indagati, essi richiedono lo sviluppo e l’impiego di sorgenti di plasma, tipi di scarica, reattori, condizioni e procedure sperimentali diversi. Tuttavia, nonostante queste differenze, entrambe le linee di ricerca derivano da conoscenze comuni e condividono lo stesso obiettivo: comprendere e sfruttare l’enorme potenziale chimico dei plasmi atmosferici. Anche nella ricerca è stato quindi applicato un approccio comune, basato su uno studio approfondito delle caratteristiche della scarica elettrica e del plasma, in particolare per quanto riguarda le specie reattive, dell’efficienza del processo e dei prodotti e degli intermedi che si formano nel processo. Gli studi meccanicistici sono basati sull’analisi quantitativa dei prodotti, sulla cinetica del processo, su misure spettroscopiche e su simulazioni. Il reattore impiegato per il trattamento delle acque è un prototipo realizzato in precedenza, in cui vengono generate scariche a barriera di dielettrico (DBD) nell’aria sovrastante la soluzione. I potenti ossidanti formati nel plasma in aria umida (radicale OH, ossigeno atomico, ozono) interagiscono con la soluzione acquosa e inducono l’ossidazione anche dei più resistenti inquinanti organici. Il fenolo, usato come inquinante organico modello, viene decomposto efficacemente, soprattutto in soluzioni diluite. La sua velocità di scomparsa aumenta linearmente con il reciproco della sua concentrazione iniziale. Nonostante l’elevata reattività, il plasma in aria mostra una certa selettività. La velocità di ossidazione di fenoli monosostituiti m-((CH3)2N-, m-Cl-, p-NO2- and m-NO2-) dipende linearmente dalle costanti di Hammett. Il valore di rho ottenuto, pari a -0.48, è caratteristico dell’attacco elettrofilo da parte del radicale OH. I principali prodotti ed intermedi della decomposizione del fenolo sono stati determinati quantitativamente. Il comportamento di due di questi intermedi, l’acido maleico e l’acido fumarico, è stato analizzato in dettaglio poiché si tratta di comuni inquinanti secondari delle acque derivanti dalla degradazione ossidativa della maggior parte dei composti aromatici. Esperimenti in cui i due acidi sono stati trattati separatamente e in miscela a diversi pH hanno permesso di indagare i meccanismi di reazione e il ruolo delle principali specie ossidanti – radicale ossidrile e ozono - nella decomposizione dei due acidi. Molto interessante ed utile è stato anche il confronto con i risultati ottenuti in esperimenti di ozonizzazione realizzati nelle stesse condizioni sperimentali ma in cui l’ozono veniva prodotto ex situ. Questi esperimenti dimostrano che in tutte le condizioni sperimentali il trattamento al plasma è più efficiente del trattamento con solo ozono grazie al contributo aggiuntivo da parte di specie a vita breve altamente reattive. Per quanto riguarda il meccanismo di ossidazione dei due acidi nel plasma, è stato concluso che a causa dell’elevata reattività con ozono, il processo di decomposizione degli acidi maleico e fumarico è dovuto principalmente a questa specie. A seconda del pH della soluzione, l’ozono reagisce con le molecole organiche come tale oppure viene convertito in radicali OH. Nel sistema al plasma, radicali OH vengono prodotti anche direttamente dalla scarica elettrica e contribuiscono anch’essi all’ossidazione degli acidi maleico e fumarico, indipendentemente dal pH della soluzione. E’ quindi evidente che la formazione diretta di •OH in situ da parte della scarica costituisce un enorme vantaggio del trattamento al plasma rispetto al caso in cui l’ozono venga prodotto ex-situ, in particolare nel caso di composti che a pH acidi non siano in grado di reagire direttamente con l’ozono. Infatti, contrariamente all’ozono, il radicale OH reagisce in modo efficiente con qualsiasi composto organico, inoltre, quando viene prodotto direttamente dalla scarica la sua concentrazione è indipendente dal pH. I risultati ottenuti si sono rivelati molto utili anche per dimostrare l’importanza del trasferimento di massa dell’ozono dalla fase gas alla soluzione. Sia nel trattamento al plasma che nell’ozonizzazione l’ozono non si accumula nella soluzione ma reagisce non appena viene trasferito in acqua o direttamente sulla superficie dell’acqua. Comunque, confrontando il comportamento degli acidi maleico e fumarico nel trattamento al plasma e nell’ozonizzazione, è stato dimostrato che il vento ionico attivo nel reattore DBD e dovuto al trasferimento di specie cariche generate dalla scarica, svolge un ruolo importante nel mescolamento della soluzione. Infatti, quando l’ozono viene prodotto ex-situ è necessario agitare la soluzione con un’ancoretta magnetica perché la reazione abbia luogo nell’intera massa di acqua e non solo sulla sua superficie; al contrario, nel caso del trattamento al plasma il mescolamento magnetico aumenta la velocità della reazione ma non cambia significativamente la forma dell’andamento dell’ossidazione in funzione del tempo. Nel caso del processo di reforming di metano con CO2 attivato da plasma è stato necessario progettare e sviluppare il reattore e l’intero sistema sperimentale da zero poiché questa linea di ricerca è stata iniziata con questa Tesi. Per poter realizzare misure di spettroscopia di emissione e in vista di studi futuri sulla combinazione del plasma con la catalisi eterogenea, il reattore è stato realizzato in quarzo: due flange sono saldate alle estremità di un tubo lungo 570 mm e largo 37 mm (diametro interno), mentre un anello è saldato nel mezzo del tubo per supportare una punta di acciaio inossidabile che costituisce l’elettrodo ad alto voltaggio. Il controelettrodo, posto al potenziale di terra, ha la forma di un imbuto ed è ricoperto da una retina di acciaio. Il tubo è in buona parte riempito con cilindri di ceramica forati, mentre la zona del plasma occupa un volume di circa 40 cm3 nel mezzo del tubo, soluzione che ne permetterebbe il riscaldamento in una fornace verticale in eventuali studi futuri con catalizzatori eterogenei. La realizzazione dell’apparato sperimentale ha richiesto un grosso impegno. Il passo successivo è stato l’esecuzione di esperimenti di prova con diversi tipi di scarica per determinare il regime più efficiente per realizzare la trasformazione di metano e anidride carbonica in una miscela di idrogeno e monossido di carbonio. I risultati migliori in termini di efficienza e selettività dei prodotti sono stati ottenuti con una scarica di tipo spark, auto-innescante grazie ad un sistema di alimentazione elettrica semplice ed efficiente. La densità elettronica media del plasma, pari a 5.7 x 1014 cm-3, è stata misurata tramite tecniche di spettroscopia di emissione e la temperatura del gas, poco inferiore a 100°C, tramite una termocoppia. La caratteristica principale della scarica di tipo spark è lo sviluppo di canali filamentari di scarica, in cui la densità degli elettroni e la temperatura delle specie, vale a dire elettroni, radicali, ioni, ma anche atomi e molecole, sono significativamente maggiori di quelle della massa del gas. Nel reattore in questione questi canali filamentari di scarica occupano interamente la regione in cui si sviluppa il plasma. Di conseguenza, si può assumere che i processi elementari della reazione tra metano e anidride carbonica si verifichino all’interno di tali canali. I prodotti principali della reazione, idrogeno e monossido di carbonio, sono stati determinati quantitativamente tramite GC/FID/TCD. Alcuni sottoprodotti sono stati rivelati in basse percentuali e identificati tramite analisi GC/MS: si tratta di etano, etilene ed acetilene. Sulla base dei dati quantitativi relativi alla formazione dei prodotti e delle misure precise dei flussi di entrata ed uscita del gas nel e dal reattore, sono state calcolate le percentuali di conversione dei reagenti e di resa e selettività dei prodotti. I risultati di conversione di CH4 (74%) e CO2 (69%), di selettività per i prodotti desiderati (78% H2 and 86% CO) e di efficienza energetica sono risultati molto buoni e rendono il sistema competitivo con altri reattori e processi descritti nella letteratura. Non viene inoltre osservata deposizione di carbone e il rapporto CO2/CH4 può essere variato tra 0.5 e 1.5 senza variazioni significative delle caratteristiche del processo. La facilità di controllo della potenza e la caratteristica di auto-innesco del sistema fanno sì che non siano necessari costosi sistemi di controllo che lavorano ad alto voltaggio e rendono promettente il ridimensionamento dell’apparato sperimentale e interessante il suo impiego in ricerche future.
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.
Повний текст джерелаNon-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
Alkawareek, Mahmoud Yousef. "Antimicrobial applications of atmospheric pressure non-thermal plasma." Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602409.
Повний текст джерелаGiardina, Agata. "Atmospheric plasma chemistry for environmental and biological applications." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3423160.
Повний текст джерелаLa Tesi riporta e discute i risultati ottenuti nell’applicazione di plasmi non termici per il trattamento ossidativo di inquinanti modello e ulteriori risultati relativi all’utilizzo del plasma in campo biomedico. L’apparato sperimentale impiegato è stato progettato e realizzato in collaborazione con il Dipartimento di Ingegneria Elettrica e produce una scarica a barriera di dielettrico (reattore DBD). Il sistema era già in uso nel periodo antecedente l’inizio della mia attività di dottorato. Le specie reattive che si generano a causa della scarica elettrica nell’aria umida sovrastante la fase liquida entrano in contatto con essa e possono reagire con l’inquinante organico in soluzione. Le specie reattive possono essere distinte in primarie, cioè generate direttamente dalla scarica per reazione del gas con gli elettroni energetici formando radicali, ioni e specie eccitate altamente reattive ed instabili, e secondarie prodotte per reazione delle stesse specie con le molecole del gas oppure con l’umidità presente. Il primo passo è stato quello di applicare tali scariche elettriche per il trattamento di diverse categorie di inquinanti emergenti allo scopo di valutare le potenziali applicazioni di questa tecnologia in relazione alle proprietà chimico fisiche degli inquinanti trattati. Sono stati selezionati i seguenti contaminanti organici persistenti: il sulfametossazolo, un antibiotico veterinario, il triclosan, un antibatterico, l’acido perfluoroacetico e tre erbicidi, l’irgarol, il metolachlor ed il mesotrione. Per tutti i composti in esame ho ottenuto profili esponenziali di degradazione in funzione del tempo di trattamento, da cui sono state ricavate le costanti cinetiche di pseudo-primo ordine. L’analisi HPLC-MS ha consentito l’identificazione degli intermedi e prodotti di degradazione, compatibili con possibili reazioni dovute all’azione dell’ozono e dei radicali ∙OH. Sono stati proposti inoltre i meccanismi di degradazione dei composti organici trattati. Lo scopo finale nell’uso di processi di degradazione avanzata è la completa conversione della componente organica a CO2. In seguito al trattamento al plasma, sono state riscontrate percentuali di mineralizzazione pari o maggiori al 93% per tutti gli inquinanti considerati, usati in concentrazione pari a 5 μM, fatta eccezione per l’acido perfluoroottanoico per cui la percentuale di mineralizzazione è stata considerevolmente più bassa (42%). Lo studio dei processi di degradazione al plasma è inoltre servito in alcuni casi da punto di partenza per ulteriori approfondimenti. È questo il caso dell’irgarol, in cui si è cercato di implementare l’effetto del plasma aggiungendo un fotocatalizzatore ampiamente utilizzato, TiO2. Non sono stati riscontrati tuttavia miglioramenti nell’effetto della scarica su tale inquinante indicando un trascurabile effetto fotocatalitico nelle condizioni sperimentali adottate. Un ulteriore avanzamento nelle ricerche in questo ambito è consistito nell’applicazione della scarica DBD su una miscela di inquinanti, il metolachlor e il mesotrione, solitamente utilizzati in combinazione in diverse formulazioni agricole. Gli studi cinetici effettuati hanno evidenziato che i due composti non si influenzano reciprocamente quando subiscono il trattamento al plasma in soluzioni miste in cui sono presenti in rapporto molare 1:1. Un importante parametro nella valutazione di una tecnica di depurazione consiste nell’analisi ecotossicologica del campione acquoso dopo il trattamento. A tale scopo, in collaborazione con il Prof. Giovanni Libralato del Dipartimento di Biologia dell’Università di Napoli, sono stati effettuati test tossicologici su campioni contenenti sulfametossazolo (SMZ), prima e dopo il trattamento nel reattore DBD. Allo scopo è stata utilizzata una batteria di test acuti e cronici per Vibrio Fischeri, Daphnia magna e Raphidocaelis subcapitata. I dati ottenuti a partire da una soluzione di SMZ 5·10-4 M hanno mostrato un elevato livello di tossicità della soluzione iniziale e la riduzione (V.fischeri) o l’azzeramento di tali effetti (D.magna e R.subcapitata) a seguito del trattamento nel reattore al plasma. Un nuovo reattore è stato inoltre ideato e realizzato in collaborazione con il Dr. Franco Bosi, del Dipartimento di Ingegneria Industriale dell’Università di Padova. La sorgente di plasma utilizza una scarica di tipo streamer ed è stata realizzata allo scopo di favorire un migliore trasporto delle specie reattive prodotte dalla scarica e ottimizzare la loro interazione con la soluzione da trattare. Il reattore è stato quindi caratterizzato in collaborazione con il Dr. Gabriele Neretti (Università di Bologna) e la Dr.ssa Barbara Zaniol (Consorzio RFX, Padova) e collaudato nel trattamento di due inquinanti organici, il fenolo ed il metolachlor. Infine nel corso di un periodo di quattro mesi di attività di ricerca presso il laboratorio della Prof.ssa Bandow dell’Università di Bochum (Germania) ho avuto modo di approfondire alcuni aspetti legati alle applicazioni del plasma atmosferico in campo biomedico. In particolare ho partecipato a studi sugli effetti di due diverse sorgenti al plasma su un enzima, gliceraldeide-3-fosfato deidrogenasi, in vitro e sul batterio E. coli. Il sito di attacco principale è risultato essere il sito attivo cisteina con conseguente ossidazione del gruppo -SH. Lo stesso approccio è stato applicato, in collaborazione con il Prof. Benedikt per lo studio degli effetti del plasma, in assenza e in presenza delle specie ioniche. I risultati ottenuti hanno evidenziato un effetto sinergico dovuto alla copresenza di specie neutre e ioniche.
Kotecha, Rutvij. "Atmospheric Pressure Microwave Plasma for Materials Processing and Environmental Applications." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1342544640.
Повний текст джерелаBIGANZOLI, ILARIA. "Characterization of atmospheric pressure plasmas for aerodynamic applications." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/53249.
Повний текст джерелаSchmidt-Bleker, Ansgar [Verfasser]. "Investigations on Cold Atmospheric Plasma Jets for Medical Applications / Ansgar Schmidt-Bleker." Greifswald : Universitätsbibliothek Greifswald, 2016. http://d-nb.info/1111579261/34.
Повний текст джерелаGozzi, Giorgia <1987>. "Atmospheric plasma processes for microbial inactivation: food applications and stress response in Listeria monocytogenes." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7171/1/Gozzi_Giorgia_tesi.pdf.
Повний текст джерелаGozzi, Giorgia <1987>. "Atmospheric plasma processes for microbial inactivation: food applications and stress response in Listeria monocytogenes." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7171/.
Повний текст джерелаCapelli, Filippo <1990>. "Integrated design of atmospheric pressure non-equilibrium plasma sources for industrial and biomedical applications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9446/1/tesi%20final.pdf.
Повний текст джерелаWang, Peiyu. "Strategy and molecular mechanism study of cold atmospheric plasma applications in oncotherapy, virucide and nanotechnology." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/214016/1/Peiyu_Wang_Thesis.pdf.
Повний текст джерелаFarouk, Tanvir Iqbal Farouk Bakhtier Friedman Alexander. "Modeling and simulations of DC and RF atmospheric pressure non-thermal micro plasma discharges : analysis and applications /." Philadelphia, Pa. : Drexel University, 2009. http://hdl.handle.net/1860/3002.
Повний текст джерелаSöderström, Daniel. "Modelling and Applications of the Hollow Cathode Plasma." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8747.
Повний текст джерелаIséni, Sylvain Roger René [Verfasser]. "Laser diagnostics of an Ar atmospheric pressure plasma jet for biomedical applications / Sylvain Roger René Iséni." Greifswald : Universitätsbibliothek Greifswald, 2015. http://d-nb.info/1076047211/34.
Повний текст джерелаGallingani, Tommaso <1991>. "Non-Equilibrium Atmospheric Plasma As A Novel Route To Nanomaterial Synthesis And Processing For Biomedical Applications." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9413/1/PhD_Thesis_Tommaso%20Gallingani_2020.pdf.
Повний текст джерелаBisag, Raluca Alina <1991>. "Development and optimization of techniques and design parameters for the engineering of atmospheric pressure plasma devices for biomedical applications and plasma medicine." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9549/1/Ph.D%20thesis_Raluca%20Alina%20Bisag_AMS%20tesi%20di%20dottorato.pdf.
Повний текст джерелаBhatt, Sudhir. "Nanometric thick copolymers elaborated by low and atmospheric pressure non-equilibrium plasmas for biomedical applications." Paris 6, 2013. http://www.theses.fr/2013PA066415.
Повний текст джерелаLes 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
Riès, Delphine. "Etude d'une décharge hors équilibre à pression atmosphérique pour des applications biomédicales : physique de la décharge, cinétique de la production des espèces réactives lors de l'interaction avec des cellules et des tissus vivants." Thesis, Orléans, 2014. http://www.theses.fr/2014ORLE2065/document.
Повний текст джерелаOver the past decade, a new type of non-equilibrium discharge at atmospheric pressure has attracted growing interest, given the ability to produce a plasma extending in ambient air close to room temperatures. These plasma jets, often based on a dielectric barrier discharge type of reactor, are interesting on their physicochemical property perspectives. In addition, these cold plasma jets have the advantage of allowing applications to heat sensitive materials, creating a new field of research, Plasma Medicine. At GREMI the Plasma Gun, has been developed for both the study of the physics of plasma jets and for biomedical applications particularly in the field of cancerology. In a first step, in vitro and in vivo were performed, within a rodent model of pancreatic carcinoma. The anti-tumor action of the plasma has been demonstrated as well as its benefic combination with a chemotherapeutic treatment. Based on these encouraging biomedical results, the main focus of this study is to report on the drastic influence of the application target on the plasma properties (propagation and production of reactive species) and on the strong coupling between gas jet and plasma discharge. Diagnostics such as fast, wavelength-filtered and Schlieren imaging, optical emission spectroscopy as well as Fourier transform infrared spectroscopy were used to characterize the plasma. A quantitative study on spatial and temporal distribution of hydroxyl radicals (OH density ranging between 5.1011 and 1.1014 cm-3) was performed by laser-induced fluorescence. The study of the OH in combination with a numerical model allowed a better understanding of the moist air penetration into the gas jet and the interaction with wet surfaces. This PhD work enlightened the complex interaction between the gas flow, the plasma and the nature of the target which has to be taken into account for further optimization of biomedical applications
Hefny, Mohamed Mokthar [Verfasser], Jan [Gutachter] Benedikt, and Achim von [Gutachter] Keudell. "Experimental study of cold atmospheric plasma for plasma medicine research and applications / Mohamed Mokthar Hefny ; Gutachter: Jan Benedikt, Achim von Keudell ; Fakultät für Physik und Astronomie." Bochum : Ruhr-Universität Bochum, 2019. http://d-nb.info/1177364018/34.
Повний текст джерелаHefny, Mohamed Mokthar Verfasser], Jan [Gutachter] Benedikt, and Achim von [Gutachter] [Keudell. "Experimental study of cold atmospheric plasma for plasma medicine research and applications / Mohamed Mokthar Hefny ; Gutachter: Jan Benedikt, Achim von Keudell ; Fakultät für Physik und Astronomie." Bochum : Ruhr-Universität Bochum, 2019. http://d-nb.info/1177364018/34.
Повний текст джерелаHefny, Mohamed Mokthar Verfasser], Jan [Gutachter] [Benedikt, and Achim von [Gutachter] Keudell. "Experimental study of cold atmospheric plasma for plasma medicine research and applications / Mohamed Mokthar Hefny ; Gutachter: Jan Benedikt, Achim von Keudell ; Fakultät für Physik und Astronomie." Bochum : Ruhr-Universität Bochum, 2019. http://d-nb.info/1177364018/34.
Повний текст джерелаSarron, Vanessa. "Etude et optimisation d'une décharge "Plasma Gun" à pression atmosphérique, pour des applications biomédicales." Thesis, Orléans, 2013. http://www.theses.fr/2013ORLE2083/document.
Повний текст джерелаThe use of plasmas, thermic or low pressure, in biomedical goes back up to 1970s. During these last years, atmospheric pressure cold plasma jets have been developed, allowed an increase of biomedical applications of plasmas. In GREMI, a plasma jet was developed : the Plasma Gun (PG). The plasma generated by the PG propagates on long distances inside capillaries. The optimization of the aimed treatments requires a detailed study of the discharges created by the PG. The characterization of the PG highlights the generation of Pulsed Atmospheric pressure Plasma Streams or PAPS, these last ones propagating from the reactor to the capillary outlet (ambient air) where they generate a plasma plume. These PAPS present two propagation modes, during which a connection between the ionization front and the reactor is present permanently. These two modes named respectively Wall-hugging and Homogeneous, differ mainly by the morphology and their propagation velocity. These modes have common characteristics, such as the possibility of division or meeting of PAPS, as well as the transfer of PAPS through a dielectric barrier or via a hollow metal capillary. The study of the plasma plume underlined the importance of the length of capillaries on the length of the plasma jet. Furthermore, the generation of the plasma has a very strong influence on the gas flow and the jet structuration during air expansion
Tricàs, Rosell Núria. "Plasma modification on carbon black surface: From reactor design to final applications." Doctoral thesis, Universitat Ramon Llull, 2007. http://hdl.handle.net/10803/9288.
Повний текст джерелаEls sistemes de plasma a baixa pressió utilitzats han estat un reactor down-stream i un reactor de llit fluiditzat. Ambdós sistemes utilitzen un generador de radio freqüències a 13,56MHz per tal de general el plasma. Tots dos sistemes han estat optimitzats per la modificació de materials en pols. En el cas del reactor down-stream, s'ha estudiat a posició d'entrada del gas reactiu, la potència del generador i el temps de modificació per a tres tipus de tractament: oxigen, nitrogen i amoníac. En el cas del reactor de llit fluiditzat, els paràmetres que s'han estudiat han estat la distància entre la pols i la zona de generació de plasma, la mida de la partícula i la porositat de la placa suport.
Pel que fa a la modificació mitjançant la utilització de plasma atmosfèric, s'ha dissenyat un sistema que permet utilitzar una torxa de plasma atmosfèric comercial (Openair® de Plasmatreat GmbH) per tal de modificar materials en pols. Aquest sistema consisteix en un reactor adaptable a la torxa de plasma atmosfèric on té lloc la modificació, un sistema d'introducció de la pols dins de la zona de reacció així com també un sistema de refredament i col·lecció del material modificat que conjuntament permeten un funcionament quasi-continu del tractament.
S'ha utilitzat el reactor down-stream i el reactor a pressió atmosfèrica per tal de modificar tres tipus diferents de negre de carboni (N134, XPB 171 i Vulcan XC-72). D'altra banda, s'ha grafititzat i extret el N134 prèviament a la modificació per tal de realitzar un estudi sobre la influència de l'estructura superficial així com també de la presència d'impureses sobre la superfície del NC. L'oxidació i l'augment de nitrogen en superfície han estat les dues modificacions que s'han estudiat principalment per tal de comparar el resultat obtingut per les tècniques presentades.
El NC s'ha caracteritzat mitjançant diverses tècniques analítiques per tal de poder obtenir informació sobre els canvis produïts durant la modificació per plasma. Aquestes tècniques inclouen superfície específica, XRD, WAXS, STM per tal d'estudiar els canvis en la seva morfologia i estructura de la superfície. D'altra banda, per tal d'estudiar els canvis en la composició química s'han emprat mesures de pH, valoracions àcid/base i XPS.
Finalment, alguns dels negres de caboni modificats han estat seleccionats per tal de ser avaluats en aplicacions finals tal i com són el reforçament d'elastòmers i la seva activitat vers la reducció d'oxigen utilitzada en les PEMFC per tal d'eliminar els metalls nobles. En el primer cas, s'ha estudiat l'efecte sobre la cinètica i el mecanisme de vulcanització del negre de carboni modificat mitjançant el plasma atmosfèric. Aquest estudi s'ha dut a terme utilitzant dues tècniques complementaries com són les corbes reomètriques i la vulcanització de molècules model (MCV). També s'han realitzat mesures d'adsorció de polímer sobre el NC i Bound Rubber per tal d'estudiar la interacció polímer-càrrega la qual presenta una gran influència en les propietats finals dels materials. D'altra banda, s'ha estudiat també la capacitat del NC modificat vers a la reducció d'oxigen a partir de voltametria cíclica i s'han determinat les propietats del NC que poden influir de manera rellevant en l'activitat cataítica final del NC per a aquesta reacció. Tot i que es necessari fer una preparació posterior al tractament de plasma per a aquesta aplicació, el material final pot contribuir notablement a la eliminació de metalls nobles com a catalitzadors de reducció d'oxigen en les Piles de Combustible.
The present works deals with plasma modification of carbon black (CB). Although this type of treatment is widely used on flat surfaces handling problems should be overcome in order to treat powders as CB. In this study CB has been modified both by means of low-pressure and atmospheric pressure non-equilibrium plasmas. In order to accomplish this objective three different plasma reactors have been set-up; two at low pressure and one at atmospheric pressure working conditions.
Low pressure plasma reactors utilised in this work consist in a down-stream and a fluidised bed system working at Radio Frequency generation power (RF 13,56 MHz). Both reactors have been optimized to treat powder materials. For the down-stream reactor, position of the reactive gas inlet, and treatment conditions such as generator power and time have been studied for oxygen, nitrogen and ammonia treatments. For the fluidized bed reactor the distance of the powder sample to the plasma generation zone, particle size and support porosity have been taken into account.
Concerning atmospheric plasma, a device has been set up in order to adapt a commercial plasma torch (Openair® from Plasmatreat GmbH), for powder modification. An adaptable reactor, a method to introduce the powder in the plasma zone as well as a collecting system had been developed in order to obtain a quasi-continuous modification treatment.
Three types of CBs, N134, XPB 171 and Vulcan XC-72 have been modified in both the down-stream and the atmospheric plasma system. Graphitization and extraction of N134 were also carried out before plasma modification in order to study the effect of both impurities and surface structure of the CB during plasma modification. Surface oxidation and nitrogen enrichment were the two main studied treatments in both systems which allowed comparing their performances.
Unmodified and Modified CBs have been characterised from several points of view. Specific surface area, XRD, WAXS and STM have been used in order to study morphological and surface structure changes. On the other hand, pH measurements, acid/base titration and XPS were employed in order to study the surface chemistry composition changes that had taken place during plasma modification.
Some of the modified CB grades were selected in order to be tested in final applications such as rubber reinforcement and oxygen reduction non-noble metal catalyst for PEMFC. In the first case, the effect of atmospheric plasma treatment on the vulcanization kinetics and mechanism has been evaluated both by rheometre curves and the model compounding approach. Studies about the polymer-filler interaction have been also carried out by calculating bound rubber and adsorption from polymer solution. Last but not least, plasma modification capacity to enhance the oxygen reduction activity to obtain non-noble metal catalysts for PEMFC has been evaluated after the correspondent preparation. Oxygen reduction activity has been studied by means of cyclic voltammetry. The main CB properties which could play an important role in such applications have been analyzed.
Laurent, Morgane. "Utilisation d'une décharge à barrière diélectrique pour développer une matrice polymère plasma dégradable pour des applications vasculaires." Thesis, Université Laval, 2017. http://www.theses.fr/2017TOU30189/document.
Повний текст джерелаEvery year, about 1.5 million patients need a vascular replacement due to advanced arteriosclerosis, which causes the internal narrowing of blood vessels. Unfortunately, even today the synthetic materials used to replace small diameter arteries (below 6 mm) remain associated with low patency rate, which demonstrates an evident lack of biocompatibility. One of the main observed complications is arterial neointimal hyperplasia, which is characterized by the blood vessel obstruction due to the tridimensional proliferation of cells on the graft internal wall. Different strategies aiming at limiting this body reaction are currently considered, in particular the use of a drug delivery system locally integrated to the vascular grafts. Concurrently, the rise of plasma technologies enabled to demonstrate the possibility to coat the surface of biomedical devices to improve their interaction with a biological environment. The strategy consists in using the plasma energy and reactivity to polymerize a gaseous precursor. By selecting the appropriate precursor molecular structure and plasma experimental conditions, one can build up a plasma polymer with tailored properties. It is in this context that this thesis consisted in synthesizing, using plasma, a biodegradable polymeric plasma polymer matrix to coat the internal wall of a vascular graft, with the goal to incorporate a drug chosen to limit neointimal hyperplasia. On one hand, this project acted as proof of concept by developing a degradable plasma polymer coating using a planar dielectric barrier discharge. After extensive studies using ethyl lactate as precursor, optimal chemical vapor deposition conditions were elected for their potential in terms of vascular applications. On the other hand, thanks to an extended discharge characterization, a strong correlation was established between the plasma physico-chemistry and the properties of the degradable coatings synthesized. In addition, to broaden possibilities in terms of degradation rate, the influence of a squared pulse power supply on the discharge and the coating was studied. If changing the way to bring the energy had a strong influence on the discharge, no major influence was noticed on the ethyl lactate-based coatings' chemistry and morphology. Finally, a tubular plasma reactor was build up to empower the internal wall of vascular prosthesis to be coated, which enabled to extend this project to the deposition conditions of its final application. Overall, this research project highlighted the potential of plasma processes for the development of degradable plasma polymer matrices, particularly for local drug delivery systems for vascular applications. On a physics perspective, this work emphasized the importance of studying the discharge under actual thin layer deposition conditions
Judée, Florian. "Liquides activés par jet de plasma froid pour le traitement sélectif du cancer colorectal : synthèse, caractérisation et essais thérapeutiques sur modèles cellulaires 3D in vitro et in vivo." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30344/document.
Повний текст джерелаPlasma devices at atmospheric pressure (AP) generate many physical active species (photons, charged particles, electric field, etc.) and chemical (free radicals, reactive oxygen species, reactive nitrogen species, etc...). This species are well known for their direct or indirect biological effects thus biomedical treatment by low temperature plasma jets at AP is currently a hot research topic. The upsurge of radioresistance and chemoresistance of microorganisms and cancer cells requires the development of new biomedical treatment. In this general context, the present work is a step towards the understanding of the effect induced by low temperature plasma jets at atmospheric pressure on colorectal cancer (second leading cause of death by cancer in France). This thesis focuses on the implementation of an in vitro biological model (multicellular tumor spheroid of colorectal cancer HCT116) in 3 dimensions which allows to take into account key parameters in tumor proliferation. This model is also well suited for the prediction of in vivo results in the aim of a subsequent clinical study. Further research about kinetic reactions of active species has been studied from the plasma device up to intracellular interactions through physical, biological and chemical analyses. Indirect treatment of tumors was carried out through helium plasma jet activated liquids. This solution was chosen for its relevance for endoscopic treatment of colorectal cancer. Interaction between plasma activated liquid and multicellular tumor spheroids has shown two distinct pathways. The first one is the genotoxicity of activated medium induced by the occurrence of hydrogen peroxide which induced DNA damages once penetrated in intracellular medium and leading to cell death by apoptosis. A direct interaction between free radicals generated in liquid medium and the latter components (amino acids, glucose, etc.) associated with the occurrence of nitrites and nitrates induces a long-term antiproliferative effect of plasma activated liquid. Chemical pathways of the formation of these active species were identified by using different analysis techniques such as electron paramagnetic resonance and optical emission spectroscopy. Therapeutic analysis have also demonstrated that plasma activated liquid damage preferentially colon cancer cells rather than healthy cells making it a particularly promising selective treatment method. The design and the characterization of a second plasma jet using argon as a carrier gas was carried out with the aim to improve the antiproliferative effect of plasmas on tumors while taking into account the requirement for the use of such device for colorectal cancer treatment
Bruno, Giuliana [Verfasser], Kristian [Akademischer Betreuer] Wende, Michael [Akademischer Betreuer] Lalk, Michael [Gutachter] Lalk, and Jan [Gutachter] Benedikt. "On the aqueous phase chemistry of atmospheric-pressure plasma jets for biomedical applications / Giuliana Bruno ; Gutachter: Michael Lalk, Jan Benedikt ; Kristian Wende, Michael Lalk." Greifswald : Universität Greifswald, 2021. http://d-nb.info/1235139832/34.
Повний текст джерелаSmejkalová, Kateřina. "Charakterizace a aplikace mikrovlnného plazmatu pro hojení ran." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-414123.
Повний текст джерелаPetersen, Julien. "Développement de surfaces fonctionnelles par polymérisation plasma à la pression atmosphérique : applications aux propriétés superhydrophobes, barrières aux gaz et aux UV." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00992185.
Повний текст джерелаOldham, Christopher John. "Applications of Atmospheric Plasmas." NCSU, 2009. http://www.lib.ncsu.edu/theses/available/etd-07062009-135218/.
Повний текст джерелаPencheva, Mariana. "Modelling of atmospheric pressure argon plasmas: application to capacitive RF and surface microwave discharges." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209451.
Повний текст джерелаDoctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished
Amorosi, Cédric. "Polymérisation par plasma froid : un outil pour l'obtention de surfaces fonctionnalisées pour les applications de type biocapteur et pour les systèmes à libération de médicaments." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00864105.
Повний текст джерелаDarny, Thibault. "Etude de la production des espèces réactives de l’oxygène et de l’azote par décharge Plasma Gun à pression atmosphérique pour des applications biomédicales." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2086/document.
Повний текст джерелаOver the past ten years, the cold atmospheric pressure plasma jets (CAPPJ) became useful devices for biomedical applications. Their relatively simple design and use, combine with their ability to produce reactive species (NO, OH, O, …), led to a rapid research growth in this field. A lot of studies have been devoted to quantitative diagnostics development for the reactive species production measurements in the plasma plume. However, it is difficult to compare one jet with another because of the huge variety of discharge geometries, electric power supplies or operating conditions. This thesis deals with the study of the CAPPJ developed in GREMI, the Plasma Gun (helium feeded, microsecond voltage pulse). We have studied discharge mechanisms which strongly impact the reactive species production in near target biomedical application conditions. This study is divided in three parts : the study of helium flow modifications induced by the plasma (strioscopy visualization); the study of plasma propagation inside dielectric capillary (experimental and numerical study of fast plasma propagation dynamic and electric field evolution for helium-nitrogen mixtures); the study of conductive target-plasma interaction (space and time resolved measurements inside the capillary and the plasma plume of helium metastable production, correlated with electric field evolution). The conductive target contact concerns any in vivo biomedical treatments. CAPPJ in front of such a conductive target leads to fundamentally different discharge mechanisms compare to the free jet case
Chauvin, Julie. "Etude des mécanismes anti-cancéreux induits par milieux activés par jet de plasma froid : vers une nouvelle approche thérapeutique." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30263/document.
Повний текст джерелаCancer therapies based on physical principles (radiofrequency, ultrasound, laser, electroporation...) have considerably increased in the last decade. Their objectives are to directly destroy cancer cells, to favor the targeted entry of therapeutic molecules or to stimulate the patient's immune system in order to eliminate the tumor. Cold plasma still arouses interest in the field of oncology through its ability to generate reactive oxygen species (ROS) and nitrogen species (RNS) which can be genotoxic and cytotoxic for cancer cells. Two approaches to the use of plasma are studied: either direct exposure of cells to the plasma jet, or indirect exposure via the use of a Plasma Activated Medium (PAM). The PAM being easier to deliver by injection into the tumor, this approach was chosen in this work. The work presented consists in studying the genotoxic and cytotoxic effects of PAM resulting from exposure of the medium to the helium plasma jet on in vitro and in vivo tumors. For in vitro studies, we chose to use a 3D model: the spheroid (MCTS - MultiCellular Tumor Spheroid). This model has similar characteristics to the in vivo model thanks to its spheroidal organization. The spheroids have indeed gradients of oxygen penetration, nutrients and cell proliferation. The first part of the thesis concerns the identification and quantification of the species generated in PAM. The analytical methods used are paramagnetic electronic resonance, fluorimetry, colorimetry, liquid chromatography and mass spectrometry. These analyses revealed that the toxicity of PAM was due to several factors: on the one hand to the generation of ROS and RNS and on the other hand to the degradation of cell nutrients contained in the medium via, for example, the oxidation and nitrosylation of the amino acids. The second part is dedicated to the study of the effects of PAM on HCT-116 (colon cancer) spheroids[...]
Adress, Wameedh. "Physics and application of an atmospheric pressure plasma jet." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669537.
Повний текст джерелаLaurita, Romolo <1986>. "Biomedical and industrial applications of atmospheric pressure non-equilibrium plasmas." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7023/1/Laurita_PhD_dissertation.pdf.
Повний текст джерелаLaurita, Romolo <1986>. "Biomedical and industrial applications of atmospheric pressure non-equilibrium plasmas." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7023/.
Повний текст джерелаBres, Lucie. "Interaction entre un plasma froid à la pression atmosphérique et des surfaces thermoplastiques industrielles : application à l'activation de surface." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30273/document.
Повний текст джерелаCarbon Fiber Reinforced Polymer (CFRP) using thermoplastic polymer matrices as Poly-EtherEtherKetone (PEEK) for example, are increasingly being used in structural engineering due to their light weight coupled with good mechanical properties. In aeronautic industry, the adhesive bonding of these composites is often required. However, their low surface energy motivates the development of robust and reliable surface activation treatments aiming at increasing the surface reactivity before painting. For this reason, we have used an atmospheric pressure plasma torch developed by AcXys Technologies(r). It is a remote plasma, well known to be an effective process to improve surface reactivity without deterioration of the bulk matrix properties. This easily implementable technology attracts many industries looking for a cost-effective and eco-friendly surface activation process. The aim of this work is to contribute to the understanding of plasma activation mechanisms leading to a greater and a more durable adhesion between PEEK matrix and an industrial painting. This study provides some insight into the effects of process parameters (device power, distance between nozzle and substrate, etc) on adhesion improvement. Mechanisms which are attributed to it are investigated by means of three point bending and crosscut adhesion standard tests. Results are discussed with respect to surface properties characterized by wettability measurements including acid-base approach, X-ray Photoelectrons Spectroscopy and Atomic Force Microscopy. In order to facilitate industrialization of atmospheric pressure remote plasma as surface activation technique, this study proposes a new approach aiming at allowing a better and more equitable comparison between atmospheric pressure plasma processes. This comparison is made through the "plasma dose" expression, similar to the one commonly used in Corona process. It is applicable for one plasma gas and accounts for both received energy and interaction time of the post-discharge with the surface. Mechanisms assigned to improvement of adhesion will be more appreciated and their characterization will contribute to a greater definition of industrial surface preparation range by remote plasma
Staack, David Alexander Farouk Bakhtier Friedman Alexander. "Characterization and stabilization of atmospheric pressure DC microplasmas and their application to thin film deposition /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2998.
Повний текст джерелаTholin, Fabien. "Numerical simulation of nanosecond repetitively pulsed discharges in air at atmospheric pressure : Application to plasma-assisted combustion." Phd thesis, Ecole Centrale Paris, 2012. http://tel.archives-ouvertes.fr/tel-00879856.
Повний текст джерелаWargnier, Quentin. "Mathematical modeling and simulation of non-equilibrium plasmas : application to magnetic reconnection in the Sun atmosphere." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLC066.
Повний текст джерелаThe ability to model, simulate and predict magnetic reconnection (MR) is a stumbling block in order to predict space weather and geomagnetic storms, which can lead to great perturbation of satellites. Some fundamental aspects of MR are not yet well understood. The scientific issue at stake is the proper description of the unsteady energy transfer from magnetic energy to kinetic and thermal energy, which is still out of reach for the standard Magneto-hydrodynamics (MHD) models. The first objective of the present project is to develop a coherent fluid model for magnetized plasmas out of thermal and chemical equilibrium with a detailed description of the dissipative effects based on kinetic theory of gases, which thus inherits a proper mathematical structure. The second goal is the development of a new numerical strategy, with high accuracy and robustness, based on a massively parallel code with adaptive mesh refinement able to cope with the full spectrum of scales of the model and related stiffness. The whole set of transport coefficients, thermodynamics relations and chemical rates in this magnetized two-temperature setting will be studied and compared to the one in the literature used in the field. Then, we will show that the model and related numerical strategy, obtained from this transdisciplinary work involving engineering, plasma physics, solar physics, mathematics, scientific computing and HPC, is able to properly reproduce the physics of MR. The validation of the approach through a series of test-cases relevant for the application to the dynamics of solar atmosphere in connection with VKI and NASA will provide a tool, open to the community, capable of resolving several critical scientific and technological issues
Lotz, Benjamin [Verfasser]. "Plasma physical and material physical aspects of the application of atmospheric gases as a propellant for Ion-Thruster of the RIT-Type / Benjamin Lotz." Gießen : Universitätsbibliothek, 2013. http://d-nb.info/1065395140/34.
Повний текст джерелаPerito, Cardoso Rodrigo. "Plasmas micro-ondes en cavité résonnante à la pression atmosphérique : étude des plasmas d'hélium et applications au traitement des matériaux." Thesis, Vandoeuvre-les-Nancy, INPL, 2007. http://www.theses.fr/2007INPL103N/document.
Повний текст джерелаThe present work deals with the study of helium microwave plasmas at atmospheric pressure generated in a resonant cavity and their applications in surface treatment. First of all, a state of art of microwave atmospheric pressure plasmas and their applications is presented. Next, a collisional-radiative model for pure helium discharge and post-discharge is described. The results of the model are compared to experimental data obtained at 2500 K and a coherent set of cross-sections and rate constants is obtained for these conditions. Emission and absorption spectroscopy diagnostics are employed to characterize the helium plasma. The gas temperature is determined by the rotational synthetic spectra method. The evolution of the gas temperature, as a function of the input power, the concentration and the nature of impurities in helium, is measured. It turns out that the plasma volume plays a significant role on the gas temperature. The He(23S) concentration is determined by laser absorption in pulsed and continuous mode. In continuous mode, the metastable concentration is divided by 3 with 360 ppm of impurity, regardless of the nature of the impurity. Nevertheless, during the post-discharge, in pulsed mode, the nature of the impurity plays an important role. These measurements support the idea that He+ and not He2+ is the main ion. Concerning the applications, only post-discharges are utilized. We demonstrate that deposition of SiOx using hexamethyldisiloxane as precursor can be efficient. We show that titanium nitriding at high temperature is possible
Girard, Fanny. "Analyse physico-chimique de milieux liquides d’intérêt biologique exposés à des plasmas froids produits à pression atmosphérique et température ambiante." Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3025/document.
Повний текст джерелаCold plasmas are partially ionized gases, very rich in a physico-chemical point of view. This property characterizes cold plasmas today generated at atmospheric pressure and ambient temperature and was used since about fifteen years approximately for biomedical applications (haematology, dermatology, cancer research, odontology etc.). The efficiency of these cold plasmas in the field of the medicine was proved by numerous studies. However, the involved biological phenomena are not still well included, and it is essential to know what could be the possible unwanted side effects of these reactive ionized gases. The first level of interaction of plasmas with living matter is the one with the liquid phase, which is present on the tissue surface, in vivo cells or in culture. For a decade, a particular attention was thus worn in the interactions of plasmas with liquids, to bring a level of additional understanding. The understanding of these interactions constituted the axis of this work. Various cold plasmas reactors (generated at atmospheric pressure and ambient temperature) were developed, in order to control the interactions of these plasmas with the ambient air which can be problematic for the aimed applications. The nature of the gas used to initiate the plasma was modified, to know its influence on the chemical reactivity of the gas phase. For that purpose, measurements of optical emissive spectroscopy (OES) were necessary. Besides, new electrochemical sensors and methodological approaches were developed in order to identify and quantify the reactive nitrogen and oxygen (RONS) produced in physiological liquid media, exposed to these ionized gases. The electrochemical analyses were combined UV-visible absorption spectroscopy as well as other methods of chemistry (pH-metry/conductimetry). One of the aimed objectives is to establish a correlation between the reactive species generated in the gas phase and in the liquid phase. Finally, experiments allowed us to analyze the production of RONS in liquids in situ and in real time. OES measurements showed that there are numerous chemical species generated in various plasmas (NO°, HO°, O, N2+ (FNS) etc.). The analyses of the liquid phase revealed the presence of stable oxygen and nitrogen species (H2O2, NO2-, NO3-), directly correlated with the species detected in plasmas. Furthermore, the diverse methodologies of chemical analysis allowed the detection and quantification of RONS such as the peroxynitrite anion ONOO-. The obtained results should allow to arrest in a finer way the effects led by various cold plasmas in physiological liquid media to establish links with the studies led on cultured cells and on skin within the framework of a research program financed by the ANR, National Agency of the Research
Gazeli, Kristaq. "Étude expérimentale de micro-plasmas froids à la pression atmosphérique générés par des hautes tensions de formes différentes." Thesis, Pau, 2015. http://www.theses.fr/2015PAUU3019/document.
Повний текст джерелаThe present PhD thesis is devoted to the study of atmospheric pressure cold micro-plasmas produced in different Dielectric Barrier Discharge (DBD) reactors which are driven by pulsed or sinusoidal high voltages. Noble gases such as helium and argon are used as carrier gases, whereas admixtures with nitrogen and oxygen are studied as well. The formation of Reactive Nitrogen and Oxygen Species (RNS, ROS) is thus achieved, and the possibility of improving the chemical (re)activity of the plasmas is demonstrated. This is of interest in the treatment of inert or living materials (e.g. surface functionalization, cell inactivation, living tissue regeneration, etc.). Plasmas are characterized by recording electrical and optical features as a function of principal operational parameters, including voltage amplitude and frequency, gas flow rate, electrode configuration, and voltage duty cycle in the case of pulsed waveform. The physico-chemical (re)activity of the plasmas is thus evaluated, while at the same time mechanisms on the plasma generation and paths for chemistry optimization are unveiled. Finally, the efficiency of the plasma in relation to biomedical applications is tested by treating different biological systems (bacteria, liposomes, cells) while preventing any thermal effect
Fioresi, Flavia. "Modification de surface de différents matériaux pour les applications biologiques et environnementales Electrografting of diazonium salt for SPR application Atmospheric solid analysis probe-ion mobility mass spectrometry : an original approach to characterize grafting on cyclic olefin copolymer surfaces Chemical modification of the cocoa shell surface using diazonium salts Cobalt nanoparticles embedded into polydimethylsiloxane-grafted cocoa shell : functional agrowaste for CO2 capture." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR062.
Повний текст джерелаFor almost a century, the researchers have been making important efforts in order to bring new properties to materials and nowadays surface modification of materials is more than ever a very attractive research subject related to a variety of promising industrial applications. The development of simple methodology to characterize biomolecular interactions has been, over the years, an indispensable technology to support researches in the areas of biology and microbiology due its high degree of sensitivity. Surface functionalization by chemical coating is a promising solution to obtain numerous well-defined properties. This study presents the feasibility of gold surface functionalization using a chemistry based on aryldiazonium salts to the biosensors development applied to Surface Plasmon Resonance (SPR) technology. A high-quality technique used to measure biomolecular interactions in real time in a label free environment. Since many years, industrial activities are responsible to the pollution of the atmosphere. Although different greenhouse gases being involved in atmospheric pollution, CO2 is still one of the most important due its high concentrations in the atmosphere and due to its ability to induce serious health disease. Several studies in the literature have demonstrated that some adsorbents such as activated carbons, basic functionalized silica sieves, zeolites, etc.. although commercially available are still sophisticated and expensive limiting their application. However, there is still a need to capture CO2 for activities with limited operating cost. The objective of this study is to promote the cocoa shell, an agro-waste resource ready to use and easy to modify, as low-cost materials for CO2 adsorption and toxins removal from industrial waste in solution applying a chemical treatment from diazonium salts and silane compounds to modify its physic-chemical properties
YUAN, LIN CHEN, and 林貞沅. "A Pulsed Atmospheric Pressure Plasma Supply System and Applications." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/78083179789194125193.
Повний текст джерела聖約翰科技大學
自動化及機電整合研究所
97
In industrial application, usually the plasma is used to surface modification to improve the surface function and quality or yield rates for products. Since an atmospheric pressure plasma could be applied to surface modification for products with complex geometry in a lack of vacuum environment, it definitely saves a lot of operation cost. The pulsed atmospheric pressure plasma supply system (PAPPS) has unique features in lower surface charge accumulation and higher processing repeatability due to pulsed parameter adjustment from clever tuning technique in manufacturing recipes. There are two important sections described in this thesis. First section, the practical design is performed for one set of a pulsed high-voltage power supply involved a high-frequency pulsed transformer which was adapted a DC power supply and a pulsed power controller. Its electrical specifications are maximum output power of 2 kW, the operating frequencies within 25 kHz, and limited working voltage at 20 kV with a bipolar pulsed output mode. Through RS232 interface, the PC remote control system was built for setting the pulsed parameters and for monitoring the variation of electrical power outputs, which also consisted of an oscilloscope, a high voltage differentiate probe, and a current probe. Next, under appropriate dry-pressure air and high-pulsed voltage supply, the atmospheric pressure plasma jet was generated via a plasma jetting nozzle. This low-temperature plasma jet would be employed as the tool of surface treatment for work pieces at an atmospheric chamber. Through measured instruments of contact angles and 3D surface profiles, the surface characteristics were detected after surface treatment. Experimental results have demonstrated that the pulsed atmospheric pressure plasma supply system is able to offer a stable plasma stream while a tunable DC power source, pulsed parameters and air pressures. One of optimal parameters includes the operating frequency of 25 kHz and 50% duty cycle, air pressure in 0.4 kg∕cm2, and electrical power of 0.77 kW, resulting in contact angles of drop-shape varied from 65.1° fallen into 34.1° after 12 second plasma surface treatment. Also, the surface average roughness (Ra) was carried from 1.19 μm levitated to 2.17 μm after surface modification in 10 seconds. It is an obvious proof of the PAPPS system useful capability in PCB surface cleaning and activating. After plasma surface treatment, the hydrophilic feature of PCB plates has been enhanced that meaning of adherent substance ability on PCB surface is improved for component welding and in robust yield rate.
Cornelius, Carrie Elizabeth. "Novel applications of atmospheric pressure plasma on textile materials." 2009. http://www.lib.ncsu.edu/theses/available/etd-10232009-190932/unrestricted/etd.pdf.
Повний текст джерелаAnand, Venu. "Studies On Atmospheric Glow Discharge For Surface Modification Applications." Thesis, 2009. https://etd.iisc.ac.in/handle/2005/926.
Повний текст джерелаAnand, Venu. "Studies On Atmospheric Glow Discharge For Surface Modification Applications." Thesis, 2009. http://hdl.handle.net/2005/926.
Повний текст джерела簡士傑. "Study of the Characteristics and Applications of Atmospheric Pressure Plasma Jets." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/49797815433196921804.
Повний текст джерела國立清華大學
物理系
101
In study, we used atmospheric pressure plasma source (APPS) to study the effect of driving frequency on the characteristic of plasma, the effect of gas flow on the deposition process and plasma density distribution, deposition of organic silicon film, and controlling the pretilt angle of liquid crystals (LCs). The study was to investigate the driving frequency effects on the characteristics of atmospheric plasma jets system. The discharge gas is the helium. We change the power source frequency range from 10 MHz to 20 MHz. As the driving frequency is increased, we can observe the several phenomena. (1) gas breakdown voltage from 256 V down to 204 V, (2) plasma density from 0.798×〖10〗^12 〖cm〗^(-3) rose to 2.218×〖10〗^12 〖cm〗^(-3) and increase the current from 0.125 A to 0.224 A when the plasma state at highest α mode discharge, (3) sheath thickness decreased from 0.348 mm to 0.257 mm before discharge mode transition, (4) the electron excitation temperature dropped from 0.535 ev 0.316 ev when the plasma power of 25 W. Collectively, these results suggest that the high driving frequency help to improve the quality of plasma, enhance discharge efficiency, and make the atmospheric plasma jets systems have a wider application space. From the results, the gas flow distribution became non-uniform at helium flow rate of 5 slm. By modifying the structure of nozzle, the gas flow distribution became more uniform so that film deposition became uniform. Because the uniformity of film deposition is related to the plasma density distribution, the gas flow distribution effected the plasma density distribution. In study, the APPS was used to deposited the organic silicon film, HMDSO as the material. The process could control the structure and properties of the film. Results showed main bonds (Si–CH¬3 and Si–O–Si) can be controlled by molecular average energy (W/FM). The ratio of Si–O–Si increased when W/FM became large. The ratio of Si–CH¬3 was increasing with decreasing the W/FM. Si–O–Si are polar bonds, and Si–CH¬3 are non-polar bonds. Thus, if the ratio of Si–O–Si was higher than Si–CH¬3, the film became hydrophilic (surface energy could be 68 mJ/m2) and surface hardness became hard. If the ratio of Si–CH¬3 was higher than Si–CH¬3, the film became hydrophobic (surface energy could be 25 mJ/m2) and surface hardness became soft. The pretilt angle of LCs could be controlled by adjusting the surface energy of the film. When the surface energy was smaller than 34 mJ/m2, the pretilt angle approached 90o. When the surface energy was larger than 60 mJ/m2, the pretilt angle approached 0o. Therefore, the pretilt angle could be controlled by the range of surface energy from 34 to 60 mJ/m2.