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Rajpurohit, Ashok. "Development of advanced carbon/glass fibre based hybrid composites." Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM020.
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Les composites hybrides offrent un moyen efficace d'améliorer les propriétés mécaniques des matériaux composites. Cette thèse vise à comprendre le comportement mécanique et l'effet synergique offerts par de tels composites hybrides sous plusieurs conditions de chargement. L'accent est mis, non seulement sur la caractérisation mécanique, mais également sur le développement et l'optimisation de nouvelles générations de renforts hybrides, permettant ainsi une hybridation aussi bien au niveau des nappes, qu’au niveau des mèches et des fibres. Dans ce travail, les fibres de carbone et de verre sont choisies comme les deux types de renforts pour les composites hybrides. Les propriétés de ces fibres unitaires sont d'abord caractérisées pour étudier l'impact des procédés textiles. De nouveaux renforts unidirectionnels ont été fabriqués après avoir optimisé les procédés, tels que la technologie UD cousu et l'étalement des fibres. Les composites ont été fabriqués via RTM basse pression en utilisant une résine époxy. Les caractéristiques en raideur et en résistance des composites de référence, des hybrides inter-plis, intra-plis et fibre à fibre ont ensuite été caractérisées dans des conditions de charge quasi-statique en traction, compression et flexion. L'effet d’hybridation (synergique) a été évalué pour ces composites en comparant les propriétés du composite hybride avec un composite de référence en carbone. Afin de comprendre le comportement à rupture de ces composites dans différentes conditions de charge, une étude de fractographie a été réalisée. Les hybrides inter-plis font apparaître une légère augmentation de la déformation à rupture en traction mais présentent une synergie négative pour toutes les autres conditions. Les hybrides intra-plis montrent eux, un effet synergique pour les résistances à la traction et à la compression, sans réduire leur déformation à rupture. Un composite hybride fibre à fibre réalisé par étalement montre une performance mécanique supérieure par rapport à d'autres hybrides. Les résultats présentés révèlent les avantages potentiels de l'hybridation à différents niveaux et dispersions. Les résultats ouvrent une voie pour les futurs travaux sur les composites hybrides et leurs procédésHybrid composites offer an effective way of enhancing mechanical properties of composite materials. This thesis aims to understand the mechanical behaviour and synergistic effect offered by such hybrid composites in several loading conditions. The focus not only lies on mechanical characterisation but also on development and optimization of new generation of hybrid reinforcements thus allowing hybridization both at ply levels and at tow and fibre levels. In this work, carbon and glass fibres are chosen as the two types of reinforcements for hybrid composites. Single fibre properties of these fibres were first characterised to study the effect of textile processes. Novel unidirectional reinforcements have been fabricated after optimising the processes such as unidirectional stitching and spreading technology. Composites were manufactured via low pressure RTM process using an epoxy resin. Stiffness and failure characteristics of reference, interply, intraply and intermingled hybrid composites were then characterised in quasi-static tensile, compression and flexural loading conditions. The hybrid (synergistic) effect were evaluated for these composites by comparing the hybrid composite properties with a carbon reference composite. To understand the failure behaviour under different loading conditions, a fractography study was conducted. Interply hybrids slightly increase the failure strain in tension but demonstrate negative synergy in all other properties. On the other hand, intraply hybrids show a synergistic effect in both tensile and compressive strengths, while not reducing the failure strain. A spread tape intermingled hybrid composite demonstrates a superior mechanical performance when compared to other hybrids. The presented results reveal the potential benefits of hybridisation at different levels and dispersions. The results provide a driving force for future work on hybrid composites and their processing
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McCutcheon, Robert A. "Hybrid Optomechanics and the Dynamical Casimir Effect." Miami University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=miami1501191323617929.
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Fox, Matthew J. "Numerical modeling of air blast effects on hybrid structures." Morgantown, W. Va. : [West Virginia University Libraries], 2002. http://etd.wvu.edu/templates/showETD.cfm?recnum=2630.
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Thesis (M.S.)--West Virginia University, 2002.Title from document title page. Document formatted into pages; contains x, 114 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 42-45).
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Paine, Jeffrey Steven Nelson. "Multi-functional SMA hybrid composite materials and their applications /." This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-162936/.
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Donnellan, Benedict T. "Introducing the hybrid unipolar bipolar field effect transistor : the HUBFET." Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/57699/.
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Modern commercial aircraft are becoming increasingly dependent on electrical power. More and more of the systems traditionally powered by hydraulics or pneumatics are being migrated to run on electricity. One consequence of the move towards electrical power is the increase in the storage capacity of the bat- teries used to supplement the power generation. The increase in battery size increases the maximum stress that a short circuit failure can put on the power distribution system. Although such failures are extremely rare, the fail safe switches in the distribution system must be capable of handling extremely high energy short circuits and turning off the power to protect the electrical systems from damage. Traditionally aircraft have used electromechanical relays in this role. However, they are large, heavy and slow to switch. As the potential power level is increased, the slow switching becomes more of a problem. The solution is a semiconductor switch. An IGBT can handle the high short circuit currents and switches fast enough to prevent short circuits damaging key systems. However, the inherent voltage drop in the forward current path significantly reduces its efficiency during nominal operation. A power MOSFET would be considerably more efficient than an IGBT during nominal operation. However, during high current surges, the ohmic behaviour of the switch leads to extremely high power loss and thermal failure. In this thesis a solution to this problem is presented. A new class of semiconductor device is proposed that has the highly efficient low current performance of the power MOSFET and the high current handling capability of the IGBT. The device has been named the Hybrid Unipolar Bipolar Field Effect Transistor or HUBFET. The HUBFET operates in unipolar mode, like a MOSFET, at low currents and in bipolar mode, like an IGBT, at high currents. The structure of the HUBFET is a merging of the MOSFET and IGBT. It is a vertical device with a traditional MOS gate structure, however the backside consists of alternating regions of both N-type and P-type doping. Through simulation the key on-state characteristics of the HUBFET have been shown. Fabricated test modules have been tested to validate the simulations and to show how the HUBFET can dynamically transistion from unipolar to bipolar mode during a short circuit event. Following the proof of concept the pattern of implants on the backside of the device that give the HUBFET its characteristic were investigated and potential improvements to the design were identified.
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Barker, Paul Simon. "Gas sensing using an organic/silicon hybrid field-effect transistor." Thesis, Durham University, 1996. http://etheses.dur.ac.uk/5166/.
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This thesis describes the fabrication and properties of novel organic/silicon hybrid field-effect transistor gas sensors. Whilst most of the work used the emeraldine base form of the conductive polymer polyaniline, the response of a device incorporating a metal-free phthalocyanine is also reported. Arrays of p-type transistors in which the gate electrodes were replaced by 'charge-flow' capacitors were fabricated using standard semiconductor processing techniques. Each array consisted of four devices in which the width of metallisation removed from the gate electrode (total width 72 µm) varied from 0 µm (i.e. the control device) to 35 µm. Thin films of the gas-sensitive organic materials were deposited by spin-coating, and chemically patterned within the holes in the gate metallisation. A delay, referred to as the 'turn-on' response, was observed in the drain current on application of a gate voltage. This was shown to depend on the temperature, level of humidity and the presence of certain gases. The electrical operating characteristics of the hybrid device with and without the polyaniline were examined. These included capacitance-voltage measurements, the 'turn-on' response at different temperatures and the variation of threshold voltage with temperature. From these results an understanding of the effect of integrating polyaniline within a p-channel transistor structure was obtained. The 35 µm gate-hole sensor incorporating polyaniline was found to be sensitive to NO(_x) and SO(_2) at room temperature at concentrations as low as 1 or 2 ppm. Decreasing the gate-hole area, and therefore the surface area of polyaniline, reduced the sensitivity of the device. The reactions were found to be reversible, although complete recovery required approximately eight hours. A similar sensor incorporating a metal-free phthalocyanine compound was reversibly sensitive to 2 ppm NO(_x) with a more rapid recovery of five hours. There was no observable response to SO(_2) or H(_2)S up to 30 ppm.
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Frank, Alison. "Surrealism in cinema : the hybrid object and its subversive effect." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.519770.
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Forconi, Mattia. "Experimental analysis of a hybrid composite material." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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The main aim of this thesis is to investigate the mechanical properties of a hybrid composite material under static loadings. The material is a composite laminate made by layers of carbon bars and a rubber layer. The thesis can be split into three main parts. In the first part a background about carbon bar composite is given and, subsequently, the research and main results on hybrid composites is introduced. The objective of this section is to provide a base on which built the main results of this work. In the second part it is explained how the test activities have been performed and the main results obtained. In particular, the effect of the introduction
of a rubber layer has been highlighted in each type of tests. In the last part, a finite element dynamical analysis is presented. A very simple transient analysis has been performed in order to foresee the dynamic behaviour of the hybrid. In conclusion, it has been demonstrated a relevant hybrid effect in the compressive and flexural properties. Those effects can be roughly reassumed in anincreasing specific stiffness for the compressive properties and in a large improvement of flexibility in the bending test. The numerical simulation shows that an increased damping effect is present, corresponding to an increase of rubber layer thickness.
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McConville, Carmel M. "The effect of cytochalasin B on normal, transformed and hybrid cells." Thesis, Queen's University Belfast, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329370.
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Basset, Julien. "High frequency quantum noise of mesoscopic systems and current-phase relation of hybrid junctions." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00635825.
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Cette thèse est consacrée à l'étude de deux aspects de la physique mésoscopique que sont le bruit quantique haute fréquence et l'effet de proximité supraconducteur en se focalisant toutefois sur un système modèle: le nanotube de carbone.Ainsi la première partie de cette thèse est dédiée à la mesure de bruit quantique haute fréquence. Afin de mesurer ces fluctuations nous avons développé un système de détection "on-chip" original dans lequel la source de bruit et le détecteur, une jonction Supraconducteur/Isolant/Supraconducteur, sont couplés par un circuit résonant. Cela nous a permis dans un premier temps de mesurer le bruit à l'équilibre du résonateur. Son bruit comporte une forte asymétrie entre émission et absorption reliée aux fluctuations de point zéro. Une seconde étape a été de mesurer le bruit hors équilibre d'émission du passage tunnel de quasi-particules dans une jonction Josephson. Ce bruit comporte une forte dépendance en fréquence en accord avec les prédictions théoriques et nous a permis de valider le principe de détection. Finalement, nous avons pu mesurer le bruit associé au régime Kondo hors équilibre d'une boîte quantique à nanotube de carbone (énergie caractéristique kBTK avec TK la température Kondo). Ce bruit d'émission à kBTK~hν possède une forte singularité à la tension V=hν/e (ν étant la fréquence de mesure). Cette singularité est reliée aux résonances Kondo dans la densité d'états de la boîte associés aux niveaux de Fermi de chaque réservoir. A plus haute fréquence hν~3kBTK, la singularité disparaît, ce qui est compris par des effets de décohérence induits par la tension.Dans la seconde partie, nous avons développé une technique permettant de mesurer à la fois la relation courant/phase et la caractéristique courant/tension d'un lien faible séparant deux supraconducteurs. Nous avons ainsi caractérisé une jonction à base de nanotube de carbone au travers de laquelle une relation courant-phase modulable par une tension de grille a été observée. Cette relation courant/phase exhibe une forte anharmonicité lorsque le supercourant présente une relativement grande amplitude.
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Tan, Juan Edward Banking & Finance Australian School of Business UNSW. "The announcement effect of private placements of hybrid securities in Australia." Awarded by:University of New South Wales. Banking and Finance, 2004. http://handle.unsw.edu.au/1959.4/20549.
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This thesis investigates the share price response to the announcement of private placements of hybrid securities in Australia. Firstly, the size and direction of the share price response is examined. Secondly, the determinants of the share price response are examined. Where possible, comparisons are made to evidence from international markets. The sample of data tested consists of 43 announcements of convertible debt issues, 39 announcements of preference share issues and 19 announcements of option issues made between 1983 and 2000 by Australian firms. The analysis of the share price impact in response to the announcements is conducted using Maynes and Rumsey (1993) event study methodology that adjusts for thin trading. The determinants of the share price response are examined using model specifications that are derived from the theoretical literature. The analysis of the announcement effect of private placements of hybrid securities finds significant negative abnormal returns for convertible debt issues, insignificant negative abnormal returns for preference share issues and significant positive abnormal returns for option issues. In comparison to international studies, the convertible debt results are similar to public and rights issues, the insignificant preference share results are similar to other findings and the option results are similar to private placements of equity and rights issues of options. The results of the investigation of the determinants of the announcement effect of private placements of hybrid securities finds that convertible debt issues are best explained by information asymmetry - firm and issue characteristics, the information asymmetry - external monitors hypothesis, the information asymmetry - dynamic hypothesis and the agency cost hypothesis. The impact of preference share issues is best explained by information asymmetry - firm and issue characteristics, the information asymmetry - external monitors hypothesis, the agency cost hypothesis and the price pressure hypothesis. The announcement effect of option issues is best explained by information asymmetry - firm and issue characteristics, the information asymmetry -dynamic hypothesis and the optimal capital structure hypothesis.
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Paine, Jeffrey S. "Multi-functional SMA hybrid composite materials and their applications." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/38219.
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Shape memory alloy (SMA) materials such as nitinol have unique properties associated with the shape recovery effect and the material’s phase changes that have been used in a variety of actuator and sensing applications. By embedding SMA elements into host composite materials, control or modification of the SMA hybrid composite’s structural properties can be accomplished inservice, thereby increasing the hybrid composite’s structural functionality. Previous studies addressed increasing composite materials’ functionality by enabling in-service control of their dynamic response. Utilizing the SMA’s substantial recovery stress and capacity to dissipate strain energy to increase the hybrid composite’s static functionality is addressed herein. Specific applications for SMA hybrid composites include improving composite material’s impact damage resistance and composite cylinder stress and deflection control.
In stress and deflection control of cylindrical structures, SMA actuators are placed within the composite cylinder to form an active compound cylinder. The active SMA elements can significantly reduce the internal pressure-induced radial dilation and creep so that under severe loading, piston to cylinder tolerances may be maintained. Similar to a conventional metallic compound cylinder, the active compound cylinder also reduces peak cylinder hoop stresses. Hybridizing composites with nitinol improves their impact resistance because of nitinol’s tremendous capacity to absorb impact strain energy through the stress-induced martensitic phase transformation. The amount of impact damage is reduced and the material’s resistance to impact perforation at various velocities is improved. The experimental response of nitinol hybrid composites and the associated mechanics are presented. The unique toughness and resistance to permanent deformation that is a result of the stress-induced martensitic phase transformation enables the nitinol to absorb on the order of 4 times the strain energy of high alloy steel and 16 times that of many graphite/epoxy composites.
In most static applications where SMA elements are used for reinforcement, maintaining the integrity of the interface between the SMA elements and the host polymeric matrix composite material is critical to operation. The relationship between preparation of SMA elements for hybrid composite fabrication and interfacial bond strength is presented to address this issue. The mechanics of interfacial shear failure between SMA element and composite is also presented.Ph. D.
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Devesa, Canicoba Noelia. "Development and characterization of perovskite based devices : field effect transistors and solar cells." Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S117.
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L'objectif de cette thèse était l’étude de dispositifs électroniques à base de pérovskites hybrides. Dans ce cadre nous avons développé et fabriqué des transistors à effet de champ (FET) ainsi que des cellules solaires à base de perovskite. Dans le cas des transistors, en utilisant des couches minces de pérovskites hybride hautement cristallisées nous avons réalisé des transistors ambipolaires fonctionnant à la température ambiante et présentant une hystérésis faible, une transconductance élevée (pour ce type de matériau), et un rapport Ion / Ioff> 104. Dans le cadre de cette thèse l’utilisation de plusieurs diélectriques nous a permis d’obtenir une forte modulation de la conductance du canal avec des tensions de grille relativement faibles (4-6V). Dans ce cadre l’oxyde d’Hafnium de permittivité relative er=23.5 a montré de très bonnes performances et une très bonne compatibilité pour la croissance de pérovskite hybride. Après plusieurs étapes de polarisation les dispositifs ont présenté un fonctionnement stabilisé et ont été mesurés au cours des cycles consécutifs pendant 14 heures avec peu de changement dans leurs performances. Nous avons mis en évidence que l’augmentation du champ électrique a permis la formation d’un canal de trous à l’interface. La polarisation consécutive des dispositifs à base de HfO2/pérovskite a amené à la création d’un second courant d’électrons et a mis en évidence un fonctionnement ambipolaire final. L’ensemble des dispositifs ont présenté une hystérésis dont l’amplitude était parfois non négligeable. Cela a démontré la présence de charges mobiles ioniques aux interfaces qui influence les courants de sorties du dispositif. Dans la dernière partie de la thèse nous nous sommes intéressés à la croissance de pérovskite hybride pour la production de cellules solaires. Nous avons étudié les deux conditions de croissance suivantes : conditions sous air normal (humidité relative> 60%) et en atmosphère d’azote en boites à gants (humidité relative <0.1 ppm). Par ces deux voies nous avons obtenu respectivement des rendements de conversion photovoltaïque respectivement de 5% et 8%The objective of this thesis was the study of electronic devices based on hybrid perovskites. In this context we have developed and produce field effect transistors (FETs) and solar cells based on hybrid perovskite material. In the case of transistors, using thin layers of highly crystallized hybrid perovskites we have made ambipolar transistors operating at room temperature and having low hysteresis, high transconductance (for this type of material) and a ratio of Ion / Ioff > 104. In the context of this thesis, the use of several dielectrics allowed us to obtain a high modulation of the channel conductance with relatively low gate voltages (4-6V). Hafnium oxide with relative permittivity er = 23.5 showed very good performances and a very good compatibility for the hybrid perovskite growth. After several polarization steps the devices exhibited stabilized operation and were measured in consecutive cycles for 14 hours with small change in their performance. We have shown that the increase of the electric field allowed the formation of a hole channel at the interface. The successive polarization of HfO2 / perovskite-based devices led to the creation of a second electron current and demonstrated a final ambipolar device. All the devices presented a hysteresis with amplitude sometimes not negligible. This demonstrated the presence of mobile ion charges at the interfaces that influence the output currents of the device. In the last part of the thesis we focused our work in hybrid perovskite growth for the production of solar cells. We have studied two growth conditions: conditions under normal air (relative humidity> 60%) and nitrogen atmosphere in glove boxes (relative humidity <0.1 ppm). By these two paths we obtained photovoltaic conversion efficiencies of 5% and 8% respectively
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Farrell, Inez Hofner. "Navigation Tools' Effect on Learners' Achievement and Attitude." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/26815.
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Navigation tools can be used to direct the amount of learner control and interactivity available in a hypermedia hybrid CD-ROM environment. The purpose of this study was to ascertain if varying the amount of learner control and interactivity through the used of navigation tools would influence the achievement and attitude of learners. The design of the study was a quasi-experimental study with random assignment of three ability levels of students to three navigation tool treatment groups. A 3 (navigation tool treatments) by 3 (ability levels) by 2 (achievement and attitude) factorial design was employed to test the hypotheses. A module titled The Poetry Portal was constructed to test 3 navigation tools (linear, menu and search engine) and their effect on achievement and attitude scores. One hundred forty-six eighth grade students were stratified into 3 ability levels (low, middle, high) by Stanford 9 scores. The module content correlated to the English 8 Virginia Standards of Learning. Results of this study based on the data are derived from descriptive statistics, two-way ANOVA, one-way ANOVA and a Tukey/Kramer Post Hoc test. The level of significance was set at .05. Results show a significant gain in achievement for high ability level students using the navigation tool search engine. Significant difference in attitude was found for all ability levels using the navigation tool menu. Suggestions for further research in this area are included.Ph. D.
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Oktay, Fulya. "A Hybrid Recommendation System Capturing The Effect Of Time And Demographic Data." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/2/12612019/index.pdf.
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The information that World Wide Web (WWW) provides have grown up very rapidly in recent years, which resulted in new approaches for people to reach the information they need. Although web pages and search engines are indeed strong enough for us to reach what we want, it is not an efficient solution to present data and wait people to reach it. Some more creative and beneficial methods had to be developed for decreasing the time to reach the information and increase the quality of the information. Recommendation systems are one of the ways for achieving this purpose. The idea is to design a system that understands the information user wants to obtain from user actions, and to find the information similar to that. Several studies have been done in this field in order to develop a recommendation system which is capable of recommending movies, books, web sites and similar items like that. All of them are based on two main principles, which are collaborative filtering and content based recommendations. Within this thesis work, a recommendation system approach which combines both content based (CB) and collaborative filtering (CF) approaches by capturing the effect of time like purchase time or release time. In addition to this temporal behavior, the influence of demographic information of user on purchasing habits is also examined this system which is called &ldquoTDRS&rdquo
.
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Xiao, Meisheng [Verfasser]. "Dissecting cis-regulatory effect on alternative polyadenylation using hybrid mice / Meisheng Xiao." Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1117541819/34.
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Troadec, Cedric. "Hybrid superconducting/ferromagnetic metallic nanostructures : fabrication and study of the proximity effect." Thesis, Royal Holloway, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271188.
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Wang, Jianxin. "Evidence for the microwave effect during hybrid sintering and annealing of ceramics." Thesis, Loughborough University, 2005. https://dspace.lboro.ac.uk/2134/2209.
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Since about 1970, there has been growing interest in the use of microwaves for heating and material processing. Microwave heating is fundamentally different from conventional heating in which electrical resistance furnaces are typically used. In microwave heating, heat is generated internally by interaction of the microwaves with the atoms and molecules of the material. Microwave heating has many potential benefits, such as rapid heating, selective heating and low cost [1, 2], these are attributable to the volumetric nature of microwave energy deposition. In addition to the possibility of faster and more controllable temperature ramp-up, microwaves can heat one region or phase more than others due to either the method by which the microwaves are deposited in the material or differences in the dielectric properties. The latter is important during the processing of new ceramic and composite materials. All the above can be treated as the thermal action of the electromagnetic field on matter.
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Sohail, Owais Arshad. "Object Oriented Failure Modes & effect Analysis : Climate System of Hybrid Vehicles." Thesis, Karlstads universitet, Institutionen för ingenjörsvetenskap, fysik och matematik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-35750.
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In order to make the product more reliable and efficient, the failures and their occurrence related to the products should be reduced if not eliminated. To achieve that, the approach of Failure Modes Effects Analysis (FMEA) is used in the process development phase where all the aspects of the product failure are generated and studied. With the passage of time the systems began to become more complex and alone FMEA not good enough approach for the complex systems. To handle a complex system is a hard and tedious job which requires more expertise. In complex systems the individual system might have overlaps, their boundaries are often unclear. The computation of information and its transmission between the components is extensive. Object Oriented FMEA resolves these issues by identifying the structure and screening a proper boundary of the system. It looks deeply in to the operational environment and external shared resources. It then decomposes its functions and behaviors in to separable physical, logical and attributes objects. The OO-FMEA approach obeys to the objectives of modern product development process and its principles. This approach makes it comparatively much easier to analyze the complex auto-motive systems that are built in extensive electrical architecture. The systems components perform their task while being interacted, linked or even independent. In this thesis the OO-FMEA approach is implemented on the Climate System of the SPA Hybrid.
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McFarland, Chelsea Clay. "HYBRID, ROW WIDTH, AND PLANT POPULATION EFFECT ON CORN YIELD IN KENTUCKY." UKnowledge, 2013. http://uknowledge.uky.edu/pss_etds/21.
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Studies were conducted in 2011 and 2012 to determine if narrow row corn (Zea mays L.) and/or greater plant populations could affect yield, time to silking, and other physiological characteristics. Main plots of six hybrids were arranged as a randomized complete bock design with three replications. Split plots were row widths of 76-cm (wide rows) and 20-cm rows on 76-cm spacing (twin rows). Split-split plots were target plant populations of 75 000 and 111 000 plants ha-1. Corn was no-till seeded into soybean stubble near Lexington, KY in 2011 and 2012. Year interacted with most factors analyzed in the study. This was expected, given the extreme differences in weather. 2011 ASI (days) approached zero as plant population increased in wide rows in two out of four hybrids. ASI response to plant population in twin rows was not significant for any hybrid. In 2011, yield was greater in twin rows than wide rows. For significant equations, in 2011 grain yield increased as plant population increased, but in 2012 grain yield decreased as plant population increased, across both row widths. Kernel number per ear decreased as plant population increased in 2011 and 2012, but at different rates for wide and twin rows.
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Costa, Dantas Faria Jorge. "Effect of polymer and metal oxide properties on hybrid light emitting diodes." Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/43381.
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Hybrid organic/inorganic light-emitting diodes (HyLEDs) combine thin, metal oxide layers together with light-emitting organic semiconductors to create devices that are more resilient to ambient conditions than standard devices. In this thesis, HyLED performance is measured as a function of the individual organic and oxide layer properties with the aims of addressing several perceived gaps within reported literature and to consequently optimise future device design. Reported herein are the results of the insertion of a vertical zinc oxide nanorod array as a non-planar, bottom-cathode electron injection layer. Using facile solution-processing methods, a well-aligned and uniform array was deposited into which the light emitting polymer poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT) was then melt-processed to create a massive, 3D interfacial contact area for electron injection. This study recorded, for the first time, efficiency and luminance values for a vertical nanorod-based LED with maximum figures of 1.66 cd/A and 8602 cd/m2 showing their potential for display and lighting applications. The successful demonstration of these nanorod HyLEDs was due to the insertion of a poly[(9,9-dioctylfluore-nyl-2,7-diyl)-co-(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (TFB) at the F8BT/anode interface to block electrons and reduce the probability of interfacial exciton dissociation. Using post-deposition annealing and solution processing, a robust method of casting TFB onto F8BT without the need for lift-off steps is presented. In planar devices, the insertion of TFB increases the maximum recorded efficiencies from 0.024 to 1.0 cd/A and its role as an optical emission tuning layer was also demonstrated; by simply varying the layer thickness the F8BT electro-luminescence was tuned from green emission to orange. Finally, the molecular weight of F8BT was seen to significantly influence the performance of HyLEDs, with six separate batches ranging from 36 to 300 kg/mol providing a systematic device study. Importantly, these batches were extracted from a single commercial source using gel permeation chromatography to negate the possible influence of different synthesis routes and chain ends. The thesis is organised into six chapters. Chapter 1 focuses on the principles behind device design and operation with an overview of the current state of HyLED literature and a discussion of the principle materials studied. Chapter 2 provides a general description of the experimental procedures and techniques used throughout. Chapters 3 to 5 each focus on a specific experimental investigation and are largely self-contained with each presenting - along with a discussion of the results - a literature review, a list of aims and an experimental section particular to the study conducted. Finally, Chapter 6 provides general concluding remarks, expanding on the ideas of further work discussed within Chapters 3-5.
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Zhou, Xuan. "Advances in hybrid plasmonics : from passive to active functions." Thesis, Troyes, 2013. http://www.theses.fr/2013TROY0015/document.
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La plasmonique hybride est un sujet d’actualité qui exploite des interactions physiques entre nano-objets métalliques et d’autres nanomatériaux. En bénéficiant des propriétés de chacun de leurs constituants, les nanostructures hybrides sont utilisées dans de nombreuses applications comme la détection d’espèces bio-chimiques. Dans cette thèse, nous présentons une nouvelle nanostructure hybride polymère/metal qui est non seulement utilisée comme nano-émetteur anisotrope qui s’avère aussi être un outil puissant de caractérisation du champ proche optique.La fabrication de cette nouvelle nanostructure est basée sur une approche de par photopolymérisation à l’échelle nanométrique. Cette technique, en comparaison aux méthodes traditionnelles de caractérisation, ne fournit pas seulement l’image de la distribution du champ, mais permet aussi des mesures quantitatives des plasmons de surface avec une résolution sub -5nm, incluant une description fine de la décroissance exponentielle des ondes évanescentes impliquées.A l’aide du mode plasmon dipolaire, une distribution anisotrope de matériau organique est intégrée dans le voisinage de la nanoparticule métallique. Avec une haute concentration de molécules de colorant dans le polymère, l’intensité des signaux de fluorescence et Raman du nano-émetteur hybride dépend de la polarisation incidente. À notre connaissance, il s’agit de la première réalisation d’un nano-émetteur dont le milieu à gain présente une distribution spatiale complexe le rendant sensible à la polarisationHybrid plasmonics has given rise to increasing interest in the context of the interaction between metal nano-objects and other materials. By benefiting from each of its constituents, hybrid nanostructures are commonly adopted in studies and optimization of biological and chemical sensors, nanoparticle with high plasmon resonance tunability, and nano-emitters. This PhD thesis presents a hybrid nanostructure of photopolymer/metal nanoparticle that is used as a near-field characterizing tool and as an anisotropic nano-emitter.The fabrication of this hybrid nanostructure is a near-field imprinting process based on nanoscale photopolymerization. This technique, compared with traditional near-field characterization methods, provides not only the image of the field distribution, but also enables quantification of the surface plasmon properties with sub-5nm resolution and reproduction of the exponential decay of the near-field.Under dipolar mode plasmon, the photopolymer was created anisotropically in the vicinity of the metal nanoparticle. With high concentration of dye molecules trapped in the polymer, the hybrid nano-emitter displays surface enhanced fluorescence and Raman signal that is dependent on the incident polarization. To our knowledge, this is the first achievement of the anisotropic nano-emitter based on the inhomogeneous distribution of the active molecule
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Jamalbastami, M. "The effect of induced discontinuities on the mechanical and hybrid cutting of rocks." Thesis, University of Newcastle Upon Tyne, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244896.
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Parrish, Austin R. "Effect of hybrid/complex N-glycosylation on cardiac voltage-gated ion channel expression." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1558106533403433.
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Dahiya, Abhishek Singh. "Nanostructures en ZnO pour l'électronique et la récupération d'énergie." Thesis, Tours, 2016. http://www.theses.fr/2016TOUR4007/document.
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Les nanomatériaux et nanotechnologies sont devenus un élément incontournable dans l'électronique de faible puissance, la production énergétique / gestion et les réseaux sans fil, offrant la possibilité de construire une vision pour les capteurs autonomes. Cette thèse s’intéresse au concept de systèmes basse température utilisant des structures de matériaux hybrides organique/inorganique pour la réalisation de dispositifs électroniques faible coût, dont les transistors à effet de champ (FET) et les nanogénérateurs piézoélectriques (nommés PENGs) et ce, sur divers substrats en particulier plastiques. Pour atteindre ces objectifs, ce travail décrit d'abord la croissance contrôlée de nanostructures monocristallines de ZnO en utilisant des approches vapeur-liquide-solide (VLS) et hydrothermales à haute et basse température respectivement. Pour les dispositifs FET, les nanostructures ZnO obtenues par VLS sont utilisées en raison de leur haute qualité structurale et optique. Les sections suivantes présentent des différentes études menées pour optimiser les prototypes FET, comprenant (i) les contacts métal-semiconducteur, (ii) la qualité de l'interface semi-conducteur/isolant et (iii) l'épaisseur de diélectrique organique. La dernière section examine la possibilité de fabriquer des systèmes hybrides organiques/inorganiques pour PENGs utilisant l'approche hydrothermale. Certaines des questions clés, ce qui limitent les performances PENG sont abordés : (i) l'effet de porteurs libres et (ii) l'encapsulation polymère. Ce travail démontre le fort potentiel des ZnO nanostructures pour l'avenir de l'électroniqueNanomaterials and nanotechnology has become a crucial feature in low-power electronics, energy generation/management and wireless networks, providing the opportunity to build a vision for autonomous sensors. The present thesis delivers the concept of low-temperature processable organic / inorganic hybrid systems for the realization of inexpensive electronic devices including field-effect transistors (FETs) and piezoelectric nanogenerators (PENGs) on various substrates including plastics. To achieve these objectives, this work first describes the controlled growth of single-crystalline ZnO nanostructures using high-temperature vapor-liquid-solid (VLS) and low-temperature hydrothermal approaches. For the FET devices, VLS grown ZnO nanostructures are used, owing to their high structural and optical quality. Later sections present different studies conducted to optimize the FET prototypes, includes: (i) metal-semiconductor contacts, (ii) semiconductor/insulator interface quality and (iii) organic dielectric thickness. The last section investigates the possibility to fabricate organic / inorganic hybrid systems for PENGs using hydrothermal approach. Some of the key issues, restricting the PENG performances are addressed: (i) screening effect from free charge carriers and (ii) polymer encapsulation. This work demonstrates the high potential of ZnO nanostructure for the future of electronics
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Diawara, Bandiougou. "Effect of planting date on growth, development, and yield of grain sorghum hybrids." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/13944.
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Master of ScienceDepartment of Agronomy
Scott A. Staggenborg
In Kansas, productivity of grain sorghum [Sorghum bicolor (L.) Moench] is affected by weather conditions at planting and during pollination. Planting date management and selection of hybrid maturity group can help to avoid severe environmental stresses during these sensitive stages. The hypothesis of the study was that late May planting improves grain sorghum yield, growth and development compared with late June planting. The objectives of this research were to investigate the influence of planting dates on growth, development, and yield of different grain sorghum hybrids, and to determine the optimal planting date and hybrid combination for maximum biomass and grains production. Three sorghum hybrids (early, medium , and late maturing) were planted in late May and late June without irrigation in Kansas at Manhattan/Ashland Bottom Research Station, and Hutchinson in 2010; and at Manhattan/North Farm and Hutchinson in 2011. Data on leaf area index, dry matter production, harvest index, yield and yield components were collected. Grain yield and yield components were influenced by planting date depending on environmental conditions. At Manhattan (2010), greater grain yield, number of heads per plant, harvest index, and leaf-area were obtained with late-June planting compared with late May planting, while at Hutchinson (2010) greater yield was obtained with late May planting for all hybrids. The yield component most affected at Hutchinson was the number of kernels panicle-1 and plant density. Late-May planting was favorable for late maturing hybrid (P84G62) in all locations. However, the yield of early maturing hybrid (DKS 28-05) and medium maturing hybrid (DKS 37-07) was less affected by delayed planting. The effects of planting dates on growth, development, and yield of grain sorghum hybrids were found to be variable among hybrid maturity groups and locations.
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Shi, Wei. "Growth and Behaviour : Epigenetic and Genetic Factors Involved in Hybrid Dysgenesis." Doctoral thesis, Uppsala universitet, Zoologisk utvecklingsbiologi, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4784.
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In mammals, the most frequently observed hybrid dysgenesis effects are growth disturbances and male sterility. Profound defects in placental development have been described and our work on hybrids in genus Mus has demonstrated putative hybrid dysgenesis effects that lead to defects in lipid homeostasis and maternal behavior. Interestingly, mammalian interspecies hybrids exhibit strong parent-of-origin effects in that offspring of reciprocal matings, even though genetically identical, frequently exhibit reciprocal phenotypes. Recent studies have provided strong link between epigenetic regulation and growth, behavior and placental development. Widespread disruption of genomic imprinting has been described in hybrids between closely related species of the genus Peromyscus. The studies presented in this thesis aim to investigate the effects of disrupted epigenetics states on altered growth, female infanticide and placental dysplasia observed in Mus hybrids. We showed that loss-of-imprinting (LOI) of a paternally expressed gene, Peg1, was correlated with increased body weight of F1 hybrids. Furthermore, we investigated whether LOI of Peg1 in F1 females would interfere with maternal behavior. A subset of F1 females indeed exhibited highly abnormal maternal behavior in that they rapidly attacked and killed the pups. By microarray hybridization, a large number of differentially expressed genes in the infanticidal females as compared to normally behaving females were identified. In addtion to Peg1 LOI, we studied allelic expression of numerous imprinted genes in adult Mus interspecies hybrids. In contrast to the study from Peromyscus, patterns of LOI were not consistent with a direct influence of altered expression levels of imprinted genes on growth. Finally, we investigated the allelic interaction between an X-linked locus and a paternally expressed gene, Peg3, in placental defects in Mus hybrids. This study further strengthened the notion that divergent genetic and epigenetic mechanisms may be involved in hybrid dysgenesis in diverse groups of mammals.
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Smith, Sharon. "Effect of novel electronic sterilisation methods on the components of hybrid collagen-based biomaterials." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510861.
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Villegas, Prados David. "Analysis of Hall effect thrusters using Hybrid PIC simulations and coupling to EP plume." Thesis, Luleå tekniska universitet, Rymdteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-80641.
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In the last 30 years, numerical models have been developed to properly analyze Hall eect thrusters (HET),leading to a bridge between analytical prediction/empirical intuition and experiments. For companies in thespace sector, these codes serve to much more than simply simulating the thruster, but it provides a fast, cheapand reliable tool for processes such as validation and verication procedures, as well as for technical developmentof the thruster. During the testing of the thruster, mostly measurements upstream from the thruster exhaustare obtained since the high density plasma inside the channel disturbs any measurement inside the channel. Thisresults in the company knowing about the output of the thruster performance, but having little knowledge aboutthe processes and behavior of the thruster itself. The purpose of this study is to help reduce the uncertainty,using existing software to eectively analyze and understand HETs. Because of the physical nature of theproblem, HET simulations follow a multi-scale approach where the thruster is divided into two regions: insidechannel/near-plume region and far-plume region. To study each zone dierent softwares are typically used.This thesis aims to nd a common ground between both software, coupling them and creating a line of analysisto follow when studying HETs.The present thesis will focus on the analysis of the famous SPT-100. The design of this work can be divided intotwo: an hybrid-PIC simulation with a software focusing on the inside channel and near-plume region, Hallis; andanother hybrid-PIC simulation regarding the plasma plume expansion performed with SPIS-EP. During thisproject both software were mastered. Hallis is investigated, emphasizing the empirical modelling of the electronanomalous transport inside the thruster and its consequences on the output results. A sensitivity analysis isperformed to obtain a good set of the empirical parameters that drive the overall performance of the thrusterand the plasma behavior. Once a good match persist between Hallis and nominal operating conditions, theoutput is used to construct the input injection distributions needed by the plasma expansion software (SPIS).Finally, the plasma plume is simulated and results are compared to in-house experimental data. In this way,one is able to control and understand the nal output directly from the behavior of the thruster. It is importantto mention that due to condentiality reasons, the testing data cannot be fully shown and sometimes only thetrend can be analyzed.As a results of the analysis, it is found that establishing the coupling between softwares is feasible, but Halliscode needs to include some characteristics to fully take advantage of its potential. It is determined that theion denition followed by Hallis is enough to perfectly dene the ion energy distribution as well as generalperformance parameters of the SPT-100 (thrust, ionization eciency, power...), but the poor electron modelgenerates some deviation in the results. SPIS simulations and comparison with testing data suggest that Hallisoutput is not enough to properly match the experimental measurements, especially regarding the ion angledistribution function. According to Hallis, such distribution is too narrow compared to the observed plasmaplume. This problem is found to be caused by the small simulation domain of Hallis. Hence, although couplingof the software is easy, more functionalities of Hallis would allow for a better study and more accurate results.
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Mjali, Kadephi Vuyolwethu. "Analysing the effect of FSP on MIG-laser hybrid welded 6082-T6 AA joints." Thesis, Nelson Mandela Metropolitan University, 2007. http://hdl.handle.net/10948/563.
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Friction Stir Processing (FSP) of aluminium alloys has been used to modify and improve the microstructure and relevant properties of fusion welded aluminium alloys. The effect of FSP on MIG-Laser Hybrid (MLH) welded aluminium alloy 6082-T6 mechanical and microstructural properties has been studied in this research. The FSP process was used on 6mm thick aluminium alloy plates and a tool was designed specifically for FSP, and the effect of varying speeds was analysed before the final FSP welds were made. The effect of FSP was analysed by optical microscopy, tensile, microhardness and fatigue testing. The aim of the study was to determine whether the FSP process has a beneficial influence on the mechanical properties and metallurgical integrity of MIG-Laser Hybrid welded 6082-T6 aluminium alloy with varying gap tolerances. Three welding processes were compared, namely combined Friction Stir Processing on MIG-Laser hybrid process (FSP-MLH), MLH and Friction Stir Welding (FSW) as part of the analysis. (FSP was carried out on MLH components when it was found that FSP is not an entirely complete welding process but rather a finishing process per se.) The aim of this dissertation is to investigate the effects of the FSP process on the weld quality of MLH welded joints and also to compare this to individual processes like FSW and MLH. This investigation was undertaken in order to gain an understanding of the effect of these processes on fatigue performance and microhardness distribution on aluminium alloy 6082-T6 weld joints.
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Joshi, Ninad Milind. "Study of the Effect of Unidirectional Carbon Fiber in Hybrid Glass Fiber / Carbon Fiber Sandwich Box Beams." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1386188162.
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Hossbach, Karl. "Investigation of the microwave effect." Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16285.
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Over the past decades, microwave sintering has been investigated, and the effects of microwave sintering have been demonstrated, however there is still uncertainty as to what is causing the enhancements known as the microwave effect . For a better understanding of the microwave effect , the effect of microwaves on the pore size distribution during densification has been investigated for submicron-sized zinc oxide (ZnO), which was sintered with conventional heating and varying amounts of microwave power but always maintaining exactly the same time-temperature profile. Initially, the density of the sintered samples was measured and compared; this proved that the densification of the hybrid sintered samples was increased and that the higher the level of microwaves used, the more it enhanced the densification. After this, the porosity was investigated through the use of nitrogen adsorption analysis, mercury porosimetry and Field Emission Gun Scanning Electron Microscopy (FEGSEM). Initially, it was found that sintering with microwaves reduces pores faster than for conventional sintering as expected. However, the experiments also revealed that the mechanisms of the reduction in the porosity were not different for microwave sintering compared to conventional sintering. When the porosity was compared at equivalent densities, it was observed that there was no significant difference, either in terms of the amount of porosity or the microstructure development. Since the structural development was the same for both conventional and hybrid sintering, it was concluded that the cause for the enhancement of the densification was enhanced diffusion caused by an additional driving force induced by the microwave field. The investigation of the solid-state reaction between zinc oxide and alumina was designed to investigate whether the diffusion associated with reactions was also enhanced by the use of microwaves. Therefore, zinc oxide and alumina samples were reacted as diffusion couples using conventional and hybrid heating, the latter with varying amounts of microwave power. The analyses of the reaction layer using FEGSEM showed an increase in the reaction product layer thickness when hybrid heating was used, with a higher level of microwaves yielding more growth. These results supported the view that the enhanced reaction rates were caused by enhanced diffusion, again caused by an additional driving force induced by the microwave field. For both the densification and reaction cases, the most likely additional driving force is considered to be the ponderomotive effect.
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Jampatong, Sansern. "Effect of one- and two-eared selection on stalk strength and other characters in maize /." free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9946266.
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Donolo, Marcos Angel. "An ODE solver for constrained state spaces: with applications to hybrid-system simulations." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/36025.
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This thesis presents a solver to handle constrained-state-space ODEs. This solver locates the points where any of the states go outside of the constraining set, and then, transfers the control from the continuous time ODE to the function governing the behavior of the system on the boundaries of the constrained set. The main contribution of this solver is found simulating complex right-hand-sided ODEs for long periods of time.Master of Science
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Verdolin, Rogerio. "Overvoltages and coupling effects on an ac-dc hybrid transmission system." Canadian Electric Association Conference, 1995. http://hdl.handle.net/1993/5147.
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Abstract
Adding a dc circuit to an existing transmission line is one method of significantly
increasing the power transfer capability of a transmission corridor. The resulting hybrid system has
significant coupling between the ac and dc circuits, not only because of the proximity of the circuits,
but also from the fact that they may share the same sending end or receiving end ac systems. The
resultant interaction produces overvoltages on the dc system which can be somewhat higher than for
a conventional dc scheme.
This thesis investigates the overvoltages on a hybrid ac-dc transmission system and suggests some
design considerations which could be taken into account to reduce stresses on certain critical
components which result from such an arrangement.
Blocking filters consisting of a parallel L-C combination in series with the dc converter were
included to limit the flow of fundamental frequency current in the dc line. This thesis also investigates
the proper blocking filter configuration to be used as an incorrectly chosen blocking filter can cause
resonance overvoltages on the dc line at fundamental frequency.
A method of eliminating dc components of the currents in the transformer windings of a dc converter
is presented. The method uses the technique of firing angle modulation. It is shown that merely
eliminating the fundamental frequency component on the dc side may not remove this dc component.
The impact of such control action at one converter on the other converters in the dc transmission
system is also presented. It is also shown that the undesirable side effects of such a scheme include
increased generation of non-characteristic harmonies on both the ac and dc sides. The study is
performed using an electromagnetic transients simulation program and theoretical calculations.
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Sahin, Tiras Kevser. "Magnetic field effect and other spectroscopies of organic semiconductor and hybrid organic-inorganic perovskite devices." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6495.
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This thesis consists of three main studies: magnetic field effects in thermally activated delayed fluorescent (TADF) organic light emitting diodes (OLEDs), magnetic field effects in bipolar and unipolar polythiophene (P3HT) devices and a study of hybrid organic/inorganic perovskite devices.
Spin-dependent transport and recombination processes of spin-pair species have been detected by magnetic field effect (MFE) technique in carbon-based semi- conductor devices. Magneto-electroluminescence (MEL) and magneto-conductivity have been measured as a function of the applied magnetic field, B, in light emitting diodes. TADF materials have been used instead of simple fluorescent materials in OLEDs. We have observed very large magnetic response with TADF materials.
The second study is magnetic field effects of regio-regular P3HT based OLED devices. P3HT is a well known semiconducting polymer, and its electrical properties such as magneto-conductance can be affected by an applied magnetic field. P3HT was chosen because it exhibits a sign change in magnetoresistance (MR) as the bias is increased. Unipolar and bipolar devices have been fabricated with different electrode materials to understand which model can be best to explain organic magnetoresistance effect, possibly depending on the operating regime of the device. Transport and luminescence spectroscopies were studied to isolate the different mechanisms and identify their fingerprints.
The third study is on hybrid organic-inorganic perovskite devices. With the potential of achieving very high efficiencies and the very low production costs, perovskite solar cells have become commercially attractive. Scanning electron microscopy (SEM) images and absorption spectrum of the films were compared in single-step solution, two-step solution and solution-assisted vapor deposition techniques. Grain size, morphology and thickness parameters of perovskite films were studied within these techniques. Perovskite solar cells were fabricated and their efficiencies were measured.
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Kozma, Thomas Mathias A. "Analytical Investigation of the Effect of Partially-Restrained Connections on Hybrid Moment-Resisting Steel Frames." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1406819681.
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Rahman, Muhammad Ziaur. "Mechanical Performance of Natural / Natural Fiber Reinforced Hybrid Composite Materials Using Finite Element Method Based Micromechanics and Experiments." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/6482.
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A micromechanical analysis of the representative volume element (RVE) of a unidirectional flax/jute fiber reinforced epoxy composite is performed using finite element analysis (FEA). To do so, first effective mechanical properties of flax fiber and jute fiber are evaluated numerically and then used in evaluating the effective properties of ax/jute/epoxy hybrid composite. Mechanics of Structure Genome (MSG), a new homogenization tool developed in Purdue University, is used to calculate the homogenized effective properties. Numerical results are compared with analytical solution based on rule of mixture, Halpin-Tsai as well as Tsai-Hahn equations. The effect of the volume fraction of the two different fibers is studied. Mechanical performance of hybrid composite is compared with the mechanical performance of single fiber composites. Synergistic effect due to hybridization is studied using analytical method given in literature, finite element method based MSG and Classical Lamination Theory (CLT). It is found that, when Poisson ratio is taken into consideration, elastic modulus shows synergy due to hybridization. Finally, impact properties of ax/jute/epoxy hybrid composite material are studied using Charpy impact testing.
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Viennot, Jeremie. "Charge and spin dynamics in a hybrid circuit quantum electrodynamics architecture." Phd thesis, Ecole Normale Supérieure de Paris - ENS Paris, 2014. http://tel.archives-ouvertes.fr/tel-01062841.
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Cette thèse étudie expérimentalement le mécanisme de couplage entre les degrés de liberté de charge et de spin dans des doubles boîtes quantiques et des cavités supraconductrices de grande finesse. Nous utilisons des nanotubes de carbone comme conducteurs cohérents pour nos boîtes quantiques. Nous avons conçu une expérience et développé de nouvelles méthodes de fabrication afin de pouvoir contrôler ces dispositifs. Avec ces méthodes, nous examinons le couplage résonant entre les transitions électroniques de charge dans les boîtes quantiques et la cavité micro-onde. Nous poussons le système hors équilibre pour caractériser sa dynamique et extraire ses paramètres intrinsèques. Nous étudions la possibilité d'un couplage de photons uniques avec un spin électronique individuel, en utilisant des champs effectifs non colinéaires induits par des interfaces ferromagnétiques comme ingrédient clef pour construire ce couplage. Les résultats préliminaires dans cette architecture en circuit sont prometteurs pour de futures expériences d'électrodynamique quantique en cavité avec des spins uniques.
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Masi, John William. "Effect of Control Techniques on the Performance of Semiactive Dampers." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/30851.
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A computer simulation is used to examine the effects that various control methods have on the performance of semiactive dampers in controlling the dynamics of a single suspension (quarter car) model. The level of dynamic control of this model has a direct bearing on the ride comfort and vehicle handling, when the single suspension is interpreted as a partial model of a vehicle. The dynamic results obtained when using two alternative semiactive control methods are compared to the results obtained when using the more conventional control methods of passive damping, Skyhook control, and Hybrid control. The conventional control methods results confirm that the semiactive damper possesses a number of benefits when compared to passive damping. In addition, the alternative control methods, which are Displacement Skyhook and Displacement Hybrid, do not show benefits that are superior to passive damping or the conventional semiactive control methods.
In support of the conclusions of this report, sufficient detail of the mathematical and numerical model is provided in the event that one should wish to recreate the results presented here. Next, the simulation results of each of the five control methods are presented individually. Several of the responses used in the results chapters are the transmissibility plots for the sprung and unsprung body displacement, the frequency spectrum of acceleration, and the frequency spectrum of the rattle space. In addition, the system response to a step input is calculated and, lastly, time traces are calculated, one at a time, for system excitations at the sprung and unsprung mass natural frequencies. The key dynamic measures studied are settling times, displacements, accelerations, and jerks. The responses just listed are then used in a comparison study between each of the presented control methods.Master of Science
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Abid, Ines. "Plasmonique hybride : propriétés optiques de nanostructures Au-TMD, couplage plasmon-exciton." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30333/document.
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Récemment, la famille des dichalcogénures de métaux de transition (TMDs) (MoS2, WS2, MoSe2...) a suscité l'intérêt de nombreuses équipes de recherche en raison de leurs propriétés optiques, électroniques et spintroniques exceptionnelles. Ma thèse est centrée sur l'association de monocouches de TMDs à des nano-structures plasmoniques. Ces dernières apportent une exaltation des propriétés d'absorption, de diffusion et d'émission optiques qui peuvent être mises à profit dans divers domaines d'applications tels que l'opto-électronique, la photo-catalyse ou les capteurs. Dans une première partie je me suis intéressée à l'interaction plasmon-exciton dans des systèmes hybrides constitués de couches de MoSe2 élaborés par dépôt chimique en phase vapeur (CVD) et transférées sur les nanodisques d'or. La résonance plasmon est contrôlée par le diamètre et la séparation entre les nano-disques. Grâce à des mesures de transmission optique et de photoluminescence, et à une analyse détaillée des réponses spectrales basée sur un modèle analytique et des simulations numériques, j'ai mis en évidence un couplage de type Fano entre les plasmons de surface des nanodisques et les transitions excitoniques de MoSe2. J'ai étudié la dépendance de ce couplage en fonction de la taille des disques, du nombre de monocouches de MoSe2 déposées et aussi en fonction de la température. Une analyse quantitative des résultats a été menée en simulant numériquement non seulement le champ local plasmonique mais aussi son couplage avec le moment dipolaire des transitions excitoniques. Pour compléter l'exploration des propriétés optiques du système MoSe2@Au, je me suis intéressée à la diffusion Raman dans des conditions d'excitation résonante et non-résonante de la transition hybride plasmon-exciton. L'idée principale étant que la résonance plasmonique apporte une exaltation de la diffusion Raman par effet SERS (Surface Enhanced Raman Scattering) tandis que les transitions excitoniques contribuent par l'effet Raman résonnant. Cette combinaison des résonances plasmonique et excitonique conduit à un effet SERS résonant. J'ai ainsi pu distinguer les contributions relatives de ces deux résonances, notamment grâce à l'imagerie confocale de la diffusion Raman. J'ai également montré que, dans ces conditions d'excitation résonnante de la transition plasmon-exciton, un phénomène d'hyperthermie a lieu. la modélisation par simulation numérique du champ proche optique et de la diffusion Raman a été utile pour comprendre les principaux facteurs limitatifs de l'exaltation Raman. Ensuite, la couche de MoSe2 a été utilisée comme substrat de nanoparticules d'Au. Les mesures de photoluminescence ont révélé une extinction quasi-totale de l'émission de la photoluminescence. Afin d'expliquer ce phénomène, deux possibilités ont été discutés : (i) le passage de la structure de bande électronique de la couche de TMD d'un semiconducteur à gap direct à indirect à cause de la contrainte imposée par les nanoparticules d'Au (ii) le désordre structural dû au dépôt des nanoparticules d'Au (iii) le transfert des porteurs photo- générés du semiconducteur vers le métal. Grâce aux mesures Raman, et à l'émission radiative des nanoparticules d'Au, j'ai mis en évidence un phénomène de transfert de charges entre le semi conducteur et le métal. Pour compléter les interprétations proposées, j'ai mené une étude comparative avec les propriétés optiques de couche de TMD couvertes \nolinebreak de silice. Ce travail de thèse a été mené au sein du groupe NeO du CEMES et dans le cadre d'une collaboration avec le groupe du Professeur Jun Lou de l'université de Rice à HoustonTransition metal dichalcogenide materials (TMDs) are increasingly gaining attention, due to their unique optical, spintronic, and electronic properties. These properties result from the ultimate confinement in 2D monolayers of a direct band-gap semiconductor and the lack of inversion symmetry in the crystallographic structure. To control and enhance the optical response of these materials, it is interesting to integrate them with plasmonic nano-resonators. The TMDs/plasmonic hybrid systems have been extensively studied for plasmon-enhanced optical signals, photocatalysis, photodetectors, and solar cells. In this context, this thesis deals with the interaction between TMD monolayers and gold nanostructures. In a first part, an hybrid system composed of CVD grown MoSe2 monolayers transferred on gold nanodisks was studied. Surface plasmon resonance was tuned by controlling the nanodisks size and the inter-disks separation. The optical properties of the nanostructures are probed by means of spatially resolved optical transmission and photoluminescence spectroscopies. Fano-type coupling regime between the surface plasmon of the gold nanodisks and the MoSe2 exciton was evidenced by a quantitative analysis of the optical extinction spectra based on an analytical model. Our interpretations were supported by numerical simulations. The number of MoSe2 monolayer dependence as well as the Temperature dependence of the plasmon-exciton interaction was investigated. Our results were quantatively analysed on the nanometric scale by studying the local electromagnetic near-field and the excitonic transition dipole momentum interaction. Furthermore, the Raman scattering of MoSe2@Au system was carried out. A particular situation was investigated where a resonant interaction between the surface plasmon of nanodisks and A exciton of v occur. The contribution of these two resonances leads to a resonant surface enhanced Raman scattering (SERRS) effect. The Raman Scattering excitation is selected to resonantly excite the Surface Plasmon resonance and MoSe2 excitonic transition simultaneously. The relative contribution of the surface Plasmon and the confined exciton to the resonant Raman scattering signal is pointed out. In this resonant condition, a hyperthermia effect was detected. Numerical simulations of the SERS gain were useful to figure out the main factors affecting the SERS intensity enhancement in MoSe2@Au. In a second part, the TMD monolayer was used as a substrate of Au nanoparticles. Au nanoislands were deposited on mono- and few-layered MoSe2 flakes. Photoluminescence (PL) measurements revealed a net quenching of the MoSe2 photoluminescence. To figure out the origin of this quenching three possibilities were discussed (i) the charge transfer between the TMD monolayer and the Au particles (ii) the direct to indirect gap transition of the TMD electronic band structure caused by the strain induced by the metal deposition (iii) structural disorder imparted by the nanoparticles in the TMD/metal interface. Owing to the Raman scattering measurements and using the radiative emission of the gold nanoparticles, we evidenced a charge transfetrt between the metallic nanostructures and the semiconductor. In order to complement our interpretations a comparative study with respect to optical properties of TMD covered by a silica film was carried out. The present work was held within the NeO group in CEMES, in a frame of a collaboration with the group of thr Pr. Jun Lou from Rice university, Houston
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He, Guping. "The Effect of Modified AuNPs on the Morphology and Nanostructure Orientation of PPMA-b-PMMA Block Copolymer Thin Films." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-154391.
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Block copolymer/inorganic nanoparticle hybrids draw great attention of scientists from various areas for their potential applications in diverse fields such as microelectronics, sensors, and solar cells. Inorganic nanoparticles (NPs) can be expected to be incorporated into block copolymers with order and selectivity by self-assembly of NPs and/or by synergistic self-assembly between NPs and block copolymers. The morphology and nanostructure order of block copolymers can be also adjusted and directed by incorporation of NPs. In this study, the effect of the size and modification of AuNPs on the morphology and nanostructure orientation of block copolymer PPMA-b-PMMA thin films were systematically investigated.
The lateral BCP structure in thin films was improved by adding AuNPs. The controlled location of AuNPs in the BCP thin films depended on the particle size and stabilizing species. The re-orientation of cylindrical domains depended on the modification of AuNPs. PPMA-coated AuNPs, corresponding to the lower surface energy component of BCP, were powerful in directing the cylinders from parallel to perpendicular to the substrate. These results provide a general guide for other BCP/inorganic NP hybrid systems for desired morphology and nanostructure orientation.
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Kitchen, John. "The effect of quadrature hybrid errors on a phase difference frequency estimator and methods for correction /." Title page, contents and summary only, 1991. http://web4.library.adelaide.edu.au/theses/09AS/09ask62.pdf.
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Rehman, Anique Ur. "Object Oriented Failure Mode and Effect Analysis (OO-FMEA) : Analysis on Cooling System in Hybrid Vehicles." Thesis, Karlstads universitet, Avdelningen för fysik och elektroteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-36683.
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Development of fault free systems and their risk assessment, in early phase of development were set in 1950s, which later on used as standardise techniques for safety and reliability issues in products. Failure Modes and Effect Analysis (FMEA) introduced as one of them and still considers a much reliable technique to identify and mitigate risks in early phase of system designing even though systems become complex now days. This report presents an extension to Failure Mode and Effect Analysis (FMEA), in such a way that it can be applied for safety analysis of complex systems; both for hardware and software development using object oriented approach. A systematic approach for validation and identification of failure modes were used in this method using system architecture; a complete boundary diagram with the behaviour of the system in logical, physical and attribute objects. Behaviour of selected objects were analysed using FMEA methodology with the help of system designing team, where validation and verification processes highlights possibility of redesigning or modifying component. Cabin cooling system for hybrid vehicle is used as a case study for this purpose.
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Pidaran, Kalaiyarasi. "Effect of planting geometry, hybrid maturity, and population density on yield and yield components in sorghum." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/15074.
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Master of ScienceDepartment of Agronomy
Rob M. Aiken
Mary Beth Kirkham
Prior studies indicate clumped planting can increase grain sorghum yield up to 45% under water deficit conditions by reducing tiller number, increasing radiation use efficiency, and preserving soil water for grain fill. The objective of this study was to evaluate effects of planting geometry on sorghum grain yield. The field study was conducted in seven environments with two sorghum hybrids, four populations, and two planting geometries. Crop responses included leaf area index, yield, and components of yield. Delayed planting decreased yield by 39%, and a later maturing hybrid increased yield, relative to an early hybrid, by 11% under water sufficiency. Clumped planting increased the fraction of fertile culms (culms which formed panicles) from 5-14%. It reduced the number of culms m-2 by 12% under water limiting conditions (at one of two locations) but increased culms m-2 16% under water sufficiency. Seeds per panicle and seed weight generally compensated for differences in panicles m-2, which were related to different planting population densities. Although agronomic characteristics of hybrids varying in maturity have been widely studied, little information exists concerning their physiological differences. Therefore, the objective of the greenhouse study was to determine if stomatal resistance, leaf temperature, and leaf chlorophyll content differed between two DeKalb grain sorghum [Sorghum bicolor (L.) Moench] hybrids. They were DKS 36-16 and DKS 44-20, of medium-early and medium maturity, respectively, when grown under field conditions in Kansas. Seeds were planted in a greenhouse. Stomatal resistance and leaf temperature were measured 55 days after planting with a Decagon Devices (Pullman, WA) diffusion porometer, and chlorophyll content was measured 119 days after planting with a Konica Minolta (Osaka, Japan) SPAD chlorophyll meter. The two hybrids did not differ in stomatal resistance, leaf temperature, chlorophyll content, height, and dry weight. Their difference in maturity was not evident under the greenhouse conditions. Future work needs to show if hybrids of different maturities vary in physiological characteristics
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Ramashia, Thinavhuyo Albert. "Effect of the additional electron acceptor in hybrid ZnO: P3HT:PCBM spin-coated films for photovoltaic application." University of the Western Cape, 2015. http://hdl.handle.net/11394/4779.
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>Magister Scientiae - MScIn a quest for low operational and maintenance cost solar cell devices, organic photovoltaics remain a potential source of energy worthy to be explored. In order to generate cost- effective electricity from solar energy, either the efficiency of the solar cells must be improved or alternatively the manufacturing cost must be lowered. The power conversion efficiency (PCE) of organic photovoltaics is influenced by the choice of electron acceptor material, the structure of the polymer, the morphology of the film, the interfaces between the layers and the ratio between the electron acceptor material and the polymer. Nevertheless, efficiency is still limited compared to conventional silicon based PV cells due to low mobility of charge carriers with a short exciton diffusion length in the active layer. Currently, hybrid solar cells have been considered as one of the most promising concepts to address the limited efficiency of organic solar cells. Therefore in this thesis ZnO nanoparticles were synthesized using hydrothermal assisted method. These nanoparticles were incorporated in the poly (3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM), and used as additional acceptors of electrons released from the polymer donor material, with the anticipation to increase the electron mobility, and ultimately the PCE. The thermo-gravimetric analyses revealed improved thermal stability of P3HT upon incorporating ZnO in the polymer matrix. X-ray diffraction analyses revealed that the diffraction peaks shift to higher angles when incorporating the ZnO in the P3HT:PCBM surface and this is consistent with the Raman observation. The photovoltaic properties demonstrated that the addition of ZnO nanoparticles in P3HT:PCBM bulk-heterojunction increases PCE from a baseline of ∼1.0 % in the P3HT:PCBM system to 1.7% in the P3HT:PCBM:ZnO ternary system. The enhanced PCE was due to improved absorption as compared to its counterparts. Upon increasing the addition of ZnO nanoparticles in the P3HT:PCBM matrix, the PCE decreases, due to a large phase separation between the polymer, PCBM and ZnO induced by ZnO agglomerations which resulted in increased surface roughness of the active layer. These findings signify that incorporation of ZnO nanostructures in the P3HT:PCBM polymer matrix facilitates the electron transport in the photoactive layer which results to improved efficiency.
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Khalili, Imad. "Sensibilité, sévérité et spécificités des explosions de mélanges hybrides gaz/vapeurs/poussières." Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0088/document.
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La sensibilité et la sévérité d'explosion des différents mélanges gaz/vapeur-poussière ont été étudiées grâce à des dispositifs standards (sphère de 20 L, tube de Hartmann). Les spécificités des explosions de mélanges hybrides gaz/poussière ont été mises en évidence. En fait, même pour des concentrations de gaz inférieures à la limite inférieure d'explosivité (LIE), la probabilité d'inflammation et la gravité d'explosion peuvent être considérablement augmentées, ce qui permettra notamment de conduire à de grands changements dans la détermination des zones ATEX. Il a été, par exemple, démontré que ces mélanges peuvent être explosifs même lorsque la concentration en poudre et la concentration en vapeur sont respectivement en dessous de la concentration minimale explosive et de la LIE. En outre, des effets de synergie ont été observés et la vitesse de montée en pression de mélanges hybrides peut être supérieure à celles des gaz purs. Les origines de ces spécificités ne doivent pas être recherchées dans la modification d'un paramètre unique, mais peuvent probablement être attribuées aux effets combinés sur l'hydrodynamique (propagation de la flamme), le transfert thermique et la cinétique de combustion. Des expériences ont été menées afin de souligner l'importance de chaque contribution. Basé sur des schémas cinétiques classiques à coeur rétrécissant prenant en compte des diverses contraintes lors d'une réaction non-catalytique de gaz/solide et sur des modèles de combustion homogène pour les gaz, un modèle a été développé pour représenter l'évolution temporelle de la pression d'explosion pour ces mélangesThe explosion sensitivity and severity of various gas/vapor-dust mixtures have been studied thanks to specifically modified apparatuses based on a 20 L sphere and a Hartmann tube. The specificities of gas/dust hybrid mixtures explosions have been highlighted. In fact, even for gas concentrations lower than the lower explosivity limit (LEL), the ignition probability and the explosion severity can be greatly increased, which will notably lead to great changes in the Ex zones determination. For instance, it has been shown that such mixtures can be explosive when both the dust and gas concentrations are below their respective minimum explosive concentration and LEL. Moreover, synergistic effects have been observed and the rate of pressure rise of hybrid mixtures can be greater than those of the pure gases themselves. The origins of these specificities should not be sought in the modification of a single parameter, but could probably be attributed to combined impacts on hydrodynamics (flame propagation), thermal transfer and combustion kinetics. Experiments have been carried out in order to underline the significance of each contribution. Based on classical shrinking core models taking into account the various limitations during a non-catalytic gas/solid reaction and on homogeneous combustion for gases, a model has been developed to represent the time evolution of the explosion pressure for such mixtures
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Torrado, David. "Effect of carbon black nanoparticles on the explosion severity of gas mixtures." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0199/document.
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Les explosions de mélanges de gaz inflammables/solides combustibles ne sont pas bien comprises en raison de la complexité des transferts thermiques, des mécanismes de cinétiques et des interactions entre la turbulence /combustion. L'objectif principal de ce travail est d'étudier la sévérité des explosions des nanoparticules de carbone noir/méthane afin de comprendre l'influence de l'insertion des nanoparticules sur les explosions de gaz. Des tests ont été effectués sur ces mélanges dans un tube de propagation de la flamme et dans une sphère d'explosion standard de 20 L. L'influence de la turbulence initiale et de la taille de particule élémentaire du noir de carbone a également été étudiée. Il semble que l'insertion de nanoparticules de noir de carbone augmente d'environ 10% la sévérité de l’explosion pour les mélanges pauvres en méthane. Par conséquent, il semble que les nanoparticules ont un impact sur la sévérité de l'explosion même pour les systèmes à basse turbulence, contrairement aux systèmes impliquant des poudres de taille micrométrique qui nécessitent une dispersion à des niveaux élevés de turbulence. L'augmentation de la vitesse maximale de montée en pression est plus élevée pour des poudres avec un petit diamètre de particule, notamment en raison des phénomènes de fragmentation. En outre, un modèle numérique de propagation de front de flamme associé à un mélange gaz/noir de carbone a été développé pour examiner l'influence du noir de carbone sur la propagation de la flamme. Les résultats du modèle numérique suggèrent que la contribution de la chaleur radiative favorise l'accélération de la flamme. Ces résultats sont en accord avec les résultats expérimentaux de sévérité de l'explosion pour certains mélanges hybridesFlammable gas/solid hybrid mixture explosions are not well understood because of the interaction of the thermal transfer process, the combustion kinetics mechanisms and the interactions between turbulence and combustion. The main objective on this work is to study the explosion severity and flame burning velocities of carbon black nanoparticles/methane to better understand the influence of added nanopowders in gas explosions. Tests have been performed in a flame propagation tube and in the standard 20 L explosion sphere. The influence of carbon black particles on the explosions severity and in the front flame propagation has been appreciated by comparing the results obtained for pure gas mixtures. It appeared that the carbon black nanoparticles insertion increases around 10% the explosion severity for lean methane mixtures. Therefore, it seems that nanoparticles has an impact on the severity of the explosion even for quiescent systems, contrary to systems involving micro-sized powders that requires a dispersion at high turbulence levels. The increment on the maximum rate of pressure rise is higher for powders with lower elementary particle diameter, which is notably due to the fragmentation phenomena. A flame propagation numerical model associated to a gas/carbon black mixture has been developed to examine the influence of carbon blacks on the flame propagation. The results of the numerical model suggest that the radiative heat contribution promotes the flame acceleration. This result is consistent with the experimental increase on the explosion severity for some hybrid mixtures
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Bissadi, Golnaz. "The Effect of Surfactant and Compatibilizer on Inorganic Loading and Properties of PPO-based EPMM Membranes." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23565.
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Hybrid membranes represent a promising alternative to the limitations of organic and inorganic materials for high productivity and selectivity gas separation membranes. In this study, the previously developed concept of emulsion-polymerized mixed matrix (EPMM) membranes was further advanced by investigating the effects of surfactant and compatibilizer on inorganic loading in poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based EPMM membranes, in which inorganic part of the membranes originated from tetraethylorthosilicate (TEOS).
The polymerization of TEOS, which consists of hydrolysis of TEOS and condensation of the hydrolyzed TEOS, was carried out as (i) one- and (ii) two-step processes. In the one-step process, the hydrolysis and condensation take place in the same environment of a weak acid provided by the aqueous solution of aluminum hydroxonitrate and sodium carbonate. In the two-step process, the hydrolysis takes place in the environment of a strong acid (solution of hydrochloric acid), whereas the condensation takes place in weak base environment obtained by adding excess of the ammonium hydroxide solution to the acidic solution of the hydrolyzed TEOS. For both one- and two-step processes, the emulsion polymerization of TEOS was carried out in two types of emulsions made of (i) pure trichloroethylene (TCE) solvent, and (ii) 10 w/v% solution of PPO in TCE, using different combinations of the compatibilizer (ethanol) and the surfactant (n-octanol). The experiments with pure TCE, which are referred to as a gravimetric powder method (GPM) allowed assessing the effect of different experimental parameters on the conversion of TEOS. The GPM tests also provided a guide for the synthesis of casting emulsions containing PPO, from which the EPMM membranes were prepared using a spin coating technique.
The synthesized EPMM membranes were characterized using 29Si nuclear magnetic resonance (29Si NMR), differential scanning calorimetry (DSC), inductively coupled plasma mass spectrometry (ICP-MS), and gas permeation measurements carried out in a constant pressure (CP) system.
The 29Si NMR analysis verified polymerization of TEOS in the emulsions made of pure TCE, and the PPO solution in TCE. The conversions of TEOS in the two-step process in the two types of emulsions were very close to each other. In the case of the one-step process, the conversions in the TCE emulsion were significantly greater than those in the emulsion of the PPO solution in TCE. Consequently, the conversions of TEOS in the EPMM membranes made in the two-step process were greater than those in the EPMM membranes made in the one-step process. The latter ranged between 10 - 20%, while the highest conversion in the two-step process was 74% in the presence of pure compatibilizer with no surfactant. Despite greater conversions and hence the greater inorganic loadings, the EPMM membranes prepared in the two-step process had glass transition temperatures (Tg) only slightly greater than the reference PPO membranes. In contrast, despite relatively low inorganic loadings, the EPMM membranes prepared in the one-step process had Tgs markedly greater than PPO, and showed the expected trend of an increase in Tg with the inorganic loading. These results indicate that in the case of the one-step process the polymerized TEOS was well integrated with the PPO chains and the interactions between the two phases lead to high Tgs. On the other hand, this was not the case for the EPMM membranes prepared in the two-step process, suggesting possible phase separation between the polymerized TEOS and the organic phase. The latter was confirmed by detecting no selectivity in the EPMM membranes prepared by the two-step process. In contrast, the EPMM membranes prepared in the one-step process in the presence of the compatibilizer and no surfactant showed 50% greater O2 permeability coefficient and a slightly greater O2/N2 permeability ratio compared to the reference PPO membranes.
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ZENG, HUA-JIAN, and 曾華健. "A 180-degree Hybrid with Filtering Effect." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/49684716662921800200.
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碩士大葉大學
電機工程學系
102
This thesis studies a 180-degree hybrid with filtering effect from a reference paper, and fabricates it in our laboratory with different size of printed circuit board. Different from conventional designs, this paper adds a bandpass filter design into hybrid. First, we design a 180-degree power divider/combiner, then add resonators and J-inverters to make it exhibit filtering effect. At the resonant frequency, the resonators are equal to open circuits, and the hybrid degenerates to a conventional one. When the frequency is shifting from resonant frequency, those resonators cancel the signals each other due to the J-inverter between them, and exhibit a filtering effect. index:bandpass filter、180-degree hybrid、 balun 、power divider、Stepped-Impedance Resonators