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Cristea, Laura G. "The Expression, Identification and Biochemical Characterization of the Extracellular Domain of Arabidopsis AFH2." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1417707960.
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Kulacz, Wojciech. "Regulation of Inverted Formin-1 (INF1) by Microtubule-Affinity Regulating Kinase 2 (MARK2)." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22801.
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The actin and microtubule cytoskeleton plays a critical role in the establishment of cell polarity. Cell processes like mitosis and migration rely on the reorganization of the cytoskeleton to properly function. One driver of cell polarity is the formin, Inverted Formin-1 (INF1). INF1 is able to induce F-actin formation, activate the Serum Response Factor (SRF) pathway, stabilize microtubules, associate with microtubules, and disperse the Golgi body. Regulation of INF1 is unique, since it does not possess conserved formin regulatory domains. However, INF1 does possess many potential phosphorylation sites. In this study, we demonstrate that INF1’s ability to induce F-actin stress fibers and activate SRF is inhibited by Microtubule-Affinity Regulating Kinase 2 (MARK2). Inhibition of INF1’s actin polymerization activity by MARK2 likely occurs near INF1’s C-terminus. However, MARK2 was unable to inhibit INF1’s ability to stabilize microtubules, associate with microtubules, and disperse the Golgi. Furthermore, we show that INF1 overexpression is associated with primary cilium absence and in some cases, the presence of long cilia, suggesting that INF1 plays a role in primary cilium formation.
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Shouler, Daniel Reginald. "Expanded forming limit testing for sheet forming processes." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609473.
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Kerleau, Mikaël. "Régulation biochimique et mécanique de l'assemblage de filaments d'actine par la formine." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLS583/document.
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Pour la cellule, l’assemblage du cytosquelette d’actine joue un rôle central dans son déplacement, sa division ou sa morphogenèse. Cette réorganisation est orchestrée par des protéines régulatrices et des contraintes mécaniques. Savoir comment les combinaisons de ces actions biochimiques et physiques régulent les différentes architectures d’actine reste un véritable défi.La formine protéine est un régulateur essentiel de l’actine. Ancrée à la membrane, elle assemble les filaments d’actine (nucléation et élongation) présents dans des architectures linéaires et non branchées. La formine est impliquée notamment dans la génération de filopodes, protrusions guidant la locomotion cellulaire.Une propriété remarquable est sa capacité à suivre processivement le bout barbé d’un filament qu’elle allonge, tout en stimulant son élongation en présence de profiline. La régulation de cette processivité de la formine est encore à clarifier. C’est une caractéristique importante, intervenant dans le contrôle de la longueur des filaments, dont les connaissances sont à approfondir.L’étude de cette processivité est facilitée par l’utilisation d’un outil microfluidique novateur pour l’étude de la dynamique de multiples filaments individuels d’actine in vitro. Au sein d’une chambre en PDMS, les filaments sont ancrés à la surface par un seul bout, le reste s’alignant avec le flux. Nous pouvons précisément y changer l’environnement biochimique,tandis que la friction visqueuse sur les filaments permet d’exercer une tension contrôlée sur chacun d’entre eux.Simultanément à l’action de la formine au bout barbé, j’étudie l’effet d’autres protéines ou de la vitesse d’élongation sur sa processivité, en mesurant son taux de détachement. Par ailleurs nous pouvons reproduire l’ancrage membranaire cellulaire en attachant spécifiquement nos formines à la surface. Dans la chambre, par l’intermédiaire du filament qu’elle allonge, nous pouvons alors exercer des forces et en étudier l’effet sur la formine.Premièrement, j’ai étudié l’impact de la protéine de coiffe (CP) sur l’activité de la formine au bout barbé. La liaison de ces deux protéines aubout barbé a jusqu’ici été considérée mutuellement exclusive. Nous avons observé qu’elles peuvent toutefois se retrouver simultanément liées au bout barbé, au sein d’un complexe à courte durée de vie. Ce complexe ternaire est capable de stopper l’activité du bout barbé même si l’affinité d’une protéine est réduite par la présence de l’autre. Nous proposons qu’une compétition entre la protéine de coiffe et la formine régule la dynamique du bout barbé dans des architectures où les longueurs doivent être hautement contrôlées.J’ai ensuite étudié l’influence de divers facteurs sur la processivité. La processivité est très sensible à la présence du sel et à la fraction demarquage fluorescent utilisée dans nos expériences. Nous avons également observé l’effet de la vitesse d’élongation, qui peut être modifiée en changeant la concentration en actine ou en profiline. D’une part, l’actine réduit la processivité, à n’importe quelle concentration de profiline. D’autre part, la concentration en profiline augmente cette processivité,indépendamment du taux d’élongation. Cela suggère qu’une incorporation de monomère diminue la processivité, tandis que la profiline, par sa présence au bout barbé, l’augmente.Enfin, la tension exercée sur les formines abaisse fortement la processivité : quelques piconewtons réduisent la processivité de plusieurs ordres de grandeurs. Cet effet, purement mécanique, prédomine sur les facteurs biochimiques. Ces résultats nous indiquent que les contraintes mécaniques de tension joueraient un rôle prédominant dans le contexte cellulaire. Cette étude nous aide à construire un modèle plus complet de l’élongation processive par les formines.En conclusion, ce projet permet de mieux comprendre le fonctionnement moléculaire de la formine, en particulier le mécanisme de l’élongation processive et de sa régulation<br>Actin filament assembly plays a pivotal role in cellular processes such as cell motility, morphogenis or division. Elucidating how the actin cytoskeleton is globally controlled remains a complex challenge. We know that it is orchestrated both by actin regulatory proteins and mechanical constraints.The formin protein is an essential actin regulator. Anchored to the cell membrane, it is responsible for the assembly (nucleation and elongation) of actin filaments found in linear and unbranched architectures. It is notably involved in the generation of filopodia protrusions at the leading edge of a motile cell. One important feature is that it processively tracks the barbed end of an actin filament, while stimulating its polymerization in the presence of profilin.Formin processivity and its regulation is not yet completely understood. As an important factor determining the length of the resulting filament, it must be investigated further.A perfect assay to look at formin processivity in vitro is an innovative microfuidics assay coupled to TIRF microscopy, pioneered by the team, to simultaneously track tens of individual filaments. In a designed chamber,filaments are anchored to the surface by one end, and aligned with the solution flow. We can precisely control the biochemical environment of the filaments. Moreover, we can exert and modulate forces on filaments, due to the viscous drag of flowing solutions. By varying chemical conditions during formin action at the barbed end, I investigated how others proteins or the elongation rate can modulate formin processivity, by looking at the detachment rate of formins.Moreover, we can mimic the membrane anchoring in the cell by specifically attaching formins at the surface. In our chamber, through the filament they elongate, we can apply force to formins.In complement to biochemical studies, we then investigate the effect oftension on their processivity.I first investigated the impact of a capping protein on formin action at the barbed end. Their barbed end binding is thought to be mutually exclusive.We measured that the affinity of one protein is reduced by the presence of the other. However we observed they both can bind simultaneously the barbed end, in a transient complex, which block barbed end elongation.Competition of formin and CP would regulate barbed end dynamics in a cell situation where length is tightly controlled.I next studied formin processivity dependence on various parameters. We show that processivity is sensitive to salt and labelling fraction used in our solutions. We also looked at how processivity is affected by the elongation rate, which can either be varied by actin or profilin concentration. On one hand, actin concentration reduces processivity, at any given concentrationsof profilin. On the other hand, raising the concentration of profilin increasesprocessivity, regardless of the elongation rate. This indicates that theincorporation of actin monomers decreases processivity while in contrast,the presence of the profilin at the barbed end increases it.Moreover, tension exerted on formin was observed to largely favor its detachment. In a quantitative matter, the effect of tension prevails over anyothers biochemical factor on processivity : only a few piconewtons decreaseit by several orders of magnitude. This important effect helps us build amore complete model of processive elongation. These results indicate thatmechanical stress is likely to play an important role in a cellular context.In conclusion, this project brings insights into the molecular properties offormin and helps to decipher the mechanism of processive elongation and its regulation
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Ramalingam, Nagendran. "Diaphanous-related formins." Diss., lmu, 2009. http://nbn-resolving.de/urn:nbn:de:bvb:19-106803.
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Grasty, Lawrence Victor. "Shot peen forming." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260449.
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Ellison, Samuel C. "Forming Ritual Reality." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1282576025.
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Sanay, Berkay. "Prediction Of Plastic Instability And Forming Limits In Sheet Metal Forming." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612486/index.pdf.
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The Forming Limit Diagram (FLD) is a widely used concept to represent the formability of thin metallic sheets. In sheet metal forming processes, plastic instability may occur, leading to defective products. In order to manufacture defect free products, the prediction of the forming limits of sheet metals is a very important issue. FLD&rsquo<br>s can be obtained by several experimental, empirical and theoretical methods. However, the suitability and the accuracy of these methods for a given material may vary.
In this study, FLD&rsquo<br>s are predicted by simulating Nakazima test using finite element software Pam-Stamp 2G. Strain propagation phenomenon is used to evaluate the limit strains from the finite element simulations. Two different anisotropic materials, AA2024-O and SAE 1006, are considered throughout the study and for each material, 7 different specimen geometries are analyzed. Furthermore, FLD&rsquo<br>s are predicted by theoretical approaches namely<br>Keeler&rsquo<br>s model, maximum load criteria, Swift-Hill model and Storen-Rice model. At the end of the study, the obtained FLD&rsquo<br>s are compared with the experimental results. It has been found that strain propagation phenomenon results for SAE 1006 are in a good agreement with the experimental results<br>however it is not for AA2024-O. In addition, theoretical models show some variations depending on the material considered. It has been observed that forming limit prediction using strain propagation phenomena with FE method can substantially reduce the time and cost for experimental work and trial and error process.
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Kamal, Manish. "A uniform pressure electromagnetic actuator for forming flat sheets." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127230699.
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Thesis (Ph. D.)--Ohio State University, 2005.<br>Title from first page of PDF file. Document formatted into pages; contains xxi, 261 p.; also includes graphics (some col.). Includes bibliographical references (p. 244-254). Available online via OhioLINK's ETD Center
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Tangirala, Sailesh Kumar. "EXPERIMENTAL AND NUMERICAL INVESTIGATION OF PLASMA-JET FORMING." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_theses/361.
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Sheet metal forming has found increasing applications in modern industries. To eliminate use of expensive tools during product development, thermal forming, a rapid prototyping process that is flexible enough to decrease costs has been developed. Thermal forming processes use a heat source to perform the required deformation mainly by creating a thermal difference along the thickness of the sheet. Gas flames, lasers and plasma heat sources have been used for sheet metal bending by thermal forming. An alternative to laser and gas flames, plasma-jet forming has been developed that uses a non-transferred plasma arc as a heat source. The plasma-jet forming system uses a highly controllable non-transferred plasma torch as a heat source to create the necessary thermal gradient in the sheet metal that causes the required plastic deformation. Various experiments to produce simple linear bends and other complex shapes have been conducted by using different scanning options and coupling techniques. A computer simulated model using finite element method is being developed to study key parameters affecting this process and also to measure the thermal transient temperature distribution during the process. A predictive model to relate the deformation to the temperature gradient for various materials is being developed. Simulation results that are in accordance to experimental observations will further improve this material forming process to be highly controllable and more accurate
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Bailleul, Carine Alice. "High-speed film forming." Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/19129.
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Ali, Ahmed. "Incremental sheet metal forming." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0020/MQ54441.pdf.
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Tabatabai, Mohammad Reza Majdzadeh. "Dominant channel forming discharge." Thesis, University of East Anglia, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389364.
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Stones, P. A. "New ring forming reactions." Thesis, University of Southampton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373984.
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Karvinen, T. (Tuulikki). "Ultra high consistency forming." Doctoral thesis, Oulun yliopisto, 2019. http://urn.fi/urn:isbn:9789526222639.
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Abstract This study focused on web forming at a 5–10% consistency range, termed Ultra High Consistency (UHC). The study continued work done by Gullichsen with his research groups (1981–2007) and combined it with the HC forming research done by Valmet (HC, 1999–2004). The hypothesis was that by utilizing a rotor to fluidize suspension and a wedge to eliminate the free jet and thus prevent reflocculation, web forming at UHC is feasible at commercial speeds. The research method was experimental. The bulk of the research was conducted at pilot scale. A new UHC headbox was designed and mounted on a pilot former. The key elements of the headbox are the rotor and the wedge. As fluidization forms the base for UHC forming, this was evaluated at the pilot former using image analysis. In addition, fluidization was studied using a laboratory-scale device. Besides basic paper analysis, X-ray microtomography and sheet splitting methods were utilized to analyze the sheet structure. The results show that forming is possible within the focus area, 5–10% consistency and machine speeds of 150–600 m/min, although the operation potential of the UHC former is even wider. The results demonstrate that the wedge is needed for successful UHC forming, but the rotor is not required, providing the flow rate is sufficiently high. This indicates that various forces induced by the flow itself can be adequate to fluidize suspension for forming. The critical Reynolds number of full fluidization was found to be 200–250. The Reynolds numbers were estimated utilizing the linear dependencies found between the apparent viscosity and consistency, using the maximum mean flow velocities inside the headbox, and neglecting the possible rotation of the rotor. The corresponding critical flow velocities at 10% consistency are 12 and 19 m/s for a eucalyptus and pine pulp. The velocities are on average 70 and 60% lower than those given in the literature (40–50 m/s). The results reveal that the fiber orientation of UHC sheets is planar, the floc size of the web increases with consistency, the internal bond increases linearly with the floc size, and the tensile strength appears to decrease with increasing floc size. In consequence, it is postulated that the increase in the out-of-plane strength at the expense of in-plane strength with the consistency increase results from a more flocculated structure<br>Tiivistelmä Tutkimus keskittyi rainanmuodostukseen 5–10 % sakeudessa. Sakeusalue nimitettiin ultra korkeaksi (lyhenne UHC). Tämä työ jatkoi Gullichsenin ja hänen tutkimusryhmiensä tutkimustyötä (1981–2007) ja samalla yhdisti sen Valmetin tekemään suursakeusrainaustutkimukseen (HC, 1994–2004). Työn hypoteesina oli, että käyttämällä roottoria massan fluidisoimiseen sekä ns. wedgeä eliminoimaan vapaa suihku ja estämään jälleenflokkaantuminen, rainanmuodostus UHC-sakeudessa on mahdollista kaupallisissa nopeuksissa. Tutkimusmetodi oli kokeellinen. Pääosa tutkimuksesta suoritettiin koekonemittakaavassa. Uusi UHC-perälaatikko suunniteltiin ja asennettiin koeformeille. Perälaatikon pääelementit ovat pyörivä roottori ja wedge. Koska fluidisointi muodostaa UHC-rainauksen perustan, fluidisointia evaluoitiin koekoneella käyttäen kuva-analyysiä sekä tutkittiin lisäksi käyttäen röntgenmikrotomografia ja arkin halkaisu -metodeja. Tulokset osoittavat, että rainaaminen on mahdollista määritellyllä fokusalueella, 5–10 %sakeudessa ja konenopeudella150–600 m/min, joskin UHC-formerin toimintapotentiaali on vieläkin laajempi. Tulokset osoittavat, että wedge tarvitaan onnistuneeseen UHC-muodostamiseen, mutta roottoria ei tarvita, mikäli virtausnopeus on riittävän suuri. Tämä tarkoittaa, että virtauksen aikaansaamat voimat voivat itsessään olla riittäviä massan fluidisoimiseksi rainaamista varten. Täyden fluidisaation kriittisen Reynoldsin luvun havaittiin olevan välillä 200–250. Reynoldsin luvut arvioitiin käyttäen löydettyjä viskositeetin ja sakeuden välisiä lineaarisia riippuvuuksia, päävirtauksen maksiminopeuksia perälaatikossa ja jättäen huomioon ottamatta mahdollinen roottorin pyöriminen. Reynoldsin lukuja vastaavat kriittiset virtausnopeudet 10 % sakeudessa ovat eukalyptus- ja mäntymassalla 12 ja 19 m/s. Nopeudet ovat keskimäärin 70 ja 60 % pienempiä kuin kirjallisuudessa annetut (40–50 m/s). Tulokset osoittavat, että UHC-arkeissa kuituorientaatio on tasomainen, rainan flokkikoko kasvaa sakeuden kasvaessa, palstautumislujuus kasvaa lineaarisesti flokkikoon kanssa ja vetolujuus näyttäisi laskevan flokkikoon kasvaessa. Näin ollen esitetään, että sakeuden kasvaessa tapahtuva palstautumislujuuden kasvu tasolujuuksien kustannuksella johtuu flokkaantuneemmasta rakenteesta
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Gearing, Brian P. (Brian Paul) 1972. "Friction in sheet forming." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/9413.
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Hayakawa, Tomoyasu. "Black-Hole forming Supernovae." Kyoto University, 2020. http://hdl.handle.net/2433/253091.
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McSorley, Charles P. "Forming A Culinary Architecture." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/9662.
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Architecture seeks to find harmony between pragmatics and poetics through phenomenological relationships of tectonics, placement, and culture. The choreography of these events, both physical and metaphysical,leads to a depth in the art of place making. The act of building in a certain way or attitude is read as aphorism – the statement imbedded in the physical existence of a construction is manifest in the way which its existence is made.
We (civilization) make both out of physical need and desire,the question in art is whether our motive is purely physical or becomes spiritual. How is institution achieved? What defines place and how is it made? Does tradition bind us to the past or is it the freedom to inform the present and beyond ?<br>Master of Architecture
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Arshad, Saad. "Single Point Incremental Forming : A study of Forming Parameters, Forming limits and Part accuracy of Aluminium 2024, 6061 and 7475 alloys." Thesis, KTH, Industriell produktion, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103006.
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Nowadays there is an increasingly demanding need for the development of agile manufacturing techniques that can easily be adaptable to a constant introduction of new products in the market. Single point incremental forming (SPIF) is a new innovative and feasible solution for the rapid prototyping and the manufacturing of small batch sheet parts. The process is carried out at room temperature (cold forming) and requires a CNC machining centre, a spherical tip tool and a simple support to fix the sheet being formed. This work studied the effects of step size, angle, spindle speed, and feed rate on the forming limits of Aluminium alloys namely AA 2024, AA 6061 and AA 7475 in soft annealed condition. The Study also includes measuring the strain path and determination of maximum forming limit angles for the above mentioned alloys. This thesis provides a better understanding of the influence of rotating tool in the occurrence of fracture without previous necking or fracture following previous necking. Surface and geometric accuracy of the parts manufactured was also studied and comparisons were made between the CAD files and the actual manufactured parts and then corrections were made accordingly. The main contribution of this thesis to Single stage SPIF was the successful manufacturing of a Cone shaped parts with almost vertical walls.
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Klee, Saskia Kirsten. "The molecular function and regulation of formins in the yeast Saccharomyces cerevisiae Die molekulare Funktion und Regulation von Forminen in der Hefe Saccharomyces cerevisiae /." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964584816.
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Lindgren, Michael. "Experimental and computational investigation of the roll forming process." Doctoral thesis, Luleå : Division of Material Mechanics, Luleå University of Technology, 2009. http://pure.ltu.se/ws/fbspretrieve/3340038.
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Cao, Jian Ph D. Massachusetts Institute of Technology. "Design and control of forming parameters for sheet metal forming using finite element analysis." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11776.
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Karlsson, Mikael. "Beam-Forming-Aware Link-Adaptation for Differential Beam-Forming in an LTE FDD System." Thesis, Linköpings universitet, Kommunikationssystem, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129109.
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The ability for base stations to be able to beam-form their signals, directing the signal energy to specific users, is a topic of research that has been heavily studied during the last decades. The beam-forming technique aims to increase the signal-to-interference-and-noise-ratio of the user and, consequently, increase the capacity and coverage of the communication system. One such method is the Differential Beam-Forming technique, that has been developed at Ericsson Research. In this version of beam-forming, the beams can be dynamically sharpened and widened when tracking a specific terminal, to try to optimize the signal energy sent to that terminal. Beam-forming, however, makes the link-adaptation algorithm process substantially harder to perform. The reason for this is that the link-adaptation algorithm now has to take into account not only the changing radio environment, but also the changing transmit signal that is being beam-formed. Fortunately, since the beam-formed signal is known at the point of transmission, there should be a potential to utilize this knowledge to make the link-adaptation more efficient. This thesis, investigates how the link-adaptation algorithm could be changed to perform better in beam-forming setups, as well as what information from the beam-forming algorithm that could be included and utilized in the link-adaptation algorithm. This is done by designing and investigating three new link-adaptation algorithms, in the context of Differential Beam-Forming in an LTE FDD system. The algorithms that has been designed are both of a beam-forming-aware and beam-forming-unaware character, meaning if the beam-forming information is utilized within the algorithm, or not. These algorithms have been simulated for different base station antenna array-sizes. Unfortunately, due to simulator restrictions, the terminals have been simulated in a stationary environment, which has proven to be a limiting factor for the results. However, the results still show that smarter beam-forming-aware link-adaptation could possibly be used to increase the performance of the link-adaptation when using beam-forming.
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Dehra, Mala Seth. "High velocity formability and factors affecting it." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1143214139.
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Raithatha, Ankor Mahendra. "Incremental sheet forming : modelling and path optimisation." Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:89b0ac1e-cab4-4d80-b352-4f48566c7668.
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Incremental sheet forming (ISF) is a novel metal shaping technology that is economically viable for low-volume manufacturing, customisation and rapid-prototyping. It uses a small tool that is controlled by a computer-numerically controlled sequence and the path taken by this tool over the sheet defines the product geometry. Little is currently known about how to design the tool-path to minimise geometric errors in the formed part. The work here addresses this problem by developing a model based tool-path optimisation scheme for ISF. The key issue is how to generate an efficient model for ISF to use within a path optimisation routine, since current simulation methods are too slow. A proportion of this thesis is dedicated to evaluating the applicability of the rigid plastic assumption for this purpose. Three numerical models have been produced: one based on small strain deformation, one based on limit analysis theory and another that approximates the sheet to a network of rods. All three models are formulated and solved as second-order cone programs (SOCP) and the limit analysis based model is the first demonstration of an upper-bound shell finite element (FE) problem solved as an SOCP. The models are significantly faster than commercially available FE software and simulations are compared with experimental and numerical data, from which it is shown the rigid plastic assumption is suitable for modelling deformation in ISF. The numerical models are still too slow for the path optimisation scheme, so a novel linearised model based on the concept of spatial impulse responses is also formulated and used in an optimal control based tool-path optimisation scheme for producing axisymmetric products with ISF. Off-line and on-line versions of the scheme are implemented on an ISF machine and it is shown that geometric errors are significantly reduced when using the proposed method. This work provides a new structured framework for tool-path design in ISF and it is also a novel use of feedback to compensate for geometrical errors in ISF.
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Woodward, Steven T. "Springback Calibration of Sheet Metal Components Using Impulse Forming Methods." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306683543.
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Gåård, Anders. "Wear in sheet metal forming." Licentiate thesis, Karlstad University, Faculty of Technology and Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-1592.
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<p>The general trend in the car body manufacturing industry is towards low-series production and reduction of press lubricants and car weight. The limited use of press lubricants, in combination with the introduction of high and ultra-high strength sheet materials, continuously increases the demands of the forming tools. To provide the means of forming new generations of sheet material, development of new tool materials with improved galling resistance is required, which may include tailored microstructures, introducing of specific(MC, M(C,N))carbides and nitrides, coatings and improved surface finish. In the present work, the wear mechanisms in real forming operations have been studied and emulated on a laboratory scale by developing a test equipment. The wear mechanisms identified in the real forming process, were distinguished into a sequence of events consisting of initial local adhesive wear of the sheets resulting in transfer of sheet material to the tool surfaces. Successive forming operations led to growth of the transfer layer and initiation of scratching of the sheets. Finally, scratching changed into severe adhesive wear, associated with gross macroscopic damage. The wear process was repeated in the laboratory test-equipment in sliding between several tool materials, ranging from cast iron to conventional ingot cast tool steels to advanced powder metallurgy tool steel, against dual-phase carbon steel sheets. By use of the test-equipment, selected tool materials were ranked regarding wear resistance in sliding against ferritic-martensitic steel sheets at different contact pressures.</p><p>Wear in sheet metal forming is mainly determined by adhesion; initially between the tool and sheet surface interaction and subsequently, after initiation of material transfer, between a sheet to sheet contact. Atomic force microscopy force curves showed that adhesion is sensitive to both chemical composition and temperature. By alloying of iron with 18wt.% Cr and 8wt.% Ni, alloying in itself, or changes in crystal structure, led to an increase of 3 times in adhesion at room temperature. Hence, alloying may be assumed a promising way for control of adhesive properties. Additionally, frictional heating should be controlled to avoid high adhesion as, generally, adhesion was found to increase with increasing temperature for all investigated materials.</p>
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Bewlay, B. P. "The spray forming of alloys." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382684.
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Grant, Patrick S. "Spray forming of aluminium alloys." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302790.
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Muhamad, N. "Modelling of spray forming process." Thesis, Swansea University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638270.
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This thesis reports the results of a theoretical investigation into the <i>Osprey Preform Process</i>. It focuses on the fluid and heat transfer phenomena associated with the liquid metal spray, the billet buildup and the solidification behaviour of the metal as the preform is produced. In the first part of the study, a nonlinear lumped parameter numerical model has been developed to model the physical processes taking place in the two phase spray and both fluid and thermal influences have been addressed. The analyses show the importance of the momentum exchange with the entrained gas on both velocity profiles and the temperature histories of the spray and this reflects the need to consider the total thermal design of the deposition chamber. The effect of a small amount of undercooling was also included where it was found to result in a wetter spray arriving at the deposit. The above model was incorporated in the buildup simulation for a cylindrical billet deposited onto a substrate having an axis in the horizontal plane. A series of sensitivity studies were carried out to assess the influence of some of the important chamber parameters which are mainly concerned with the position and movement of the scanner and the substrate under the spray. Although a direct comparison between the predicted billet shape and those manufactured was not posible due to the absence of data, the analyses confirmed the significant parameters which influence the billet shape produced and which have to be optimised in actual practice. These findings are compatible with the experience of <i>Osprey Metal Ltd</i>. Finally, the solidification history of the billet preform was analysed using a two dimensional thermal network method. It was found that the thermal history of the billet is sensitive to the thermal boundary conditions applied. Therefore, an appropriate choice of the spraying conditions needs to be established to produce uniform material properties throughout the billet extent.
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Deng, Li. "Cyanophages of bloom-forming cyanobacteria." Thesis, University of Bristol, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492570.
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Cyanobacteria are an important and a diverse group of photo synthetic prokaryotes found in marine, freshwater and terrestrial environments. Over the past two decades, research has shown that cyanobacterial community structures are influenced through infection by cyanobacterial viruses (cyanophages). In marine systems cyanophages have been shown to play roles in the mortality of their hosts, as well as in driving the succession and evolution of phenotypes.
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Islam, Yousuf Mahboobul. "A study of injection forming." Thesis, University of Glasgow, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304876.
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Christian, Jeff M. "Preaching as character-forming discourse." Theological Research Exchange Network (TREN), 2007. http://www.tren.com/search.cfm?p050-0159.
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Hoskins, Travis Justin Christopher. "Carbon-carbon bond forming reactions." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/29769.
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Thesis (M. S.)--Chemical Engineering, Georgia Institute of Technology, 2009.<br>Committee Chair: Dr. Christopher Jones; Committee Co-Chair: Dr. Pradeep Agrawal; Committee Member: Dr. Sujit Banerjee; Committee Member: Dr. Tom Fuller. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Gåård, Anders. "Wear in sheet metal forming /." Karlstad : Faculty of Technology and Science, Materials Engineering, Karlstad University, 2008. http://www.diva-portal.org/kau/abstract.xsql?dbid=1592.
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Saunders, Frederick I. "Forming of tailor-welded blanks." Connect to resource, 1994. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1240337228.
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Chen, Chun-Ling Jocelyn 1972. "Forming processes for advanced composites." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/31063.
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Roy, Matthew J. "Rotary forming of cast aluminum." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44789.
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The application of rotary forming to A356 offers a potential improvement in material use, simplified castings and ameliorated fatigue resistance. To investigate the utility of adopting this process industrially, an extensive characterization and modelling effort was undertaken.
The constitutive behaviour of A356 in the as-cast condition was assessed with compression tests performed over a range of deformation temperatures (30-500°C) and strain rates (~0.1-10/s). The flow stress as a function of temperature and strain rate was quantified via an extended Ludwik-Hollomon and Kocks-Mecking framework.
The through-process microstructural effects on A356 subjected to rotary forming at elevated temperatures was also investigated. This was conducted on material at 350°C with an industrially-scaled, purpose-built apparatus, inducing varying levels of spinning deformation. This was also conducted on commercially flow formed material with high levels of deformation at the same temperature. Macro and micro-hardness testing was used to track the changes from the as-cast and as-formed states, as well as following a T6 heat treatment. Further EDX analysis indicate that precipitation aspects of heat treatment is not appreciably affected by forming. Forming was found to principally affect the eutectic-Si particle size, resulting in a finer particle post heat treatment.
An explicit finite element rotary forming model reciprocating experimental forming conditions was developed incorporating the Ludwik-Hollomon description. This forming model was found to be computationally expensive; however, demonstrated reasonable agreement with experimental geometry and phenomena.
In evaluating the effect of forming on fatigue, multiaxial testing of A356-T6 was conducted to apprehend the basic fatigue mechanisms. Endurance limits are found to be generally governed by porosity and maximum principal stress for high cycle fatigue. Uniaxial fatigue tests of both experimentally and commercially formed material showed a 30% increase in endurance limits over unformed material, principally through mitigating porosity.
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Wang, Bo. "Integrated analyses in plastics forming." Thesis, Sheffield Hallam University, 1996. http://shura.shu.ac.uk/19363/.
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This is the thesis which explains the progress made in the analysis, simulation and testing of plastics forming. This progress can be applied to injection and compression mould design. Three activities of plastics forming have been investigated, namely filling analysis, cooling analysis and ejecting analysis. The filling section of plastics forming has been analysed and calculated by using MOLDFLOW and FILLCALC V. software. A comparing of high speed compression moulding and injection moulding has been made. The cooling section of plastics forming has been analysed by using MOLDFLOW software and a finite difference computer program. The latter program can be used as a sample program to calculate the feasibility of cooling different materials to required target temperatures under controlled cooling conditions. The application of thermal imaging has been also introduced to determine the actual process temperatures. Thermal imaging can be used as a powerful tool to analyse mould surface temperatures and to verify the mathematical model. A buckling problem for ejecting section has been modelled and calculated by PATRAN/ABAQUS finite element analysis software and tested. These calculations and analysis are applied to the special case but can be use as an example for general analysis and calculation in the ejection section of plastics forming.
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Hutchinson, Mark Ian. "Bulge forming of tubular components." Thesis, Sheffield Hallam University, 1988. http://shura.shu.ac.uk/19849/.
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The bulge forming process is a method for shaping tubular components using an internal hydrostatic pressure combined with a compressive axial load. Initial investigations involved carrying out an extensive literature survey to determine the components which could be formed and the effects of using lubricants and different tube materials. Die-blocks were designed to produce tee pieces, cross joints and off-set joints, and electronic on-line instrumentation was incorporated so that the forming pressures and loads could be accurately monitored. A series of tests were carried out in the forming of: (1) tee pieces, cross joints and off-set joints from copper tubes of two different wall thicknesses, (2) tee pieces using different types of plungers, (3) tee pieces using die-blocks coated with various lubricants, (4) tee pieces from aluminium, copper and steel tubes, (5) tee pieces using die-blocks with various branch radii. From the resulting components, formed with various combinations of internal pressure and compressive axial load, the limits for a successful forming operation were established. Further analysis of these components was then undertaken to evaluate the effects of the internal pressure and axial load on the bulge height and the wall thickness in the deformation zone. From these results, which have been illustrated graphically, the greatest effect on the resulting bulge can be seen to be the compressive axial load. Theoretical analyses are presented, which predict the wall thickness distribution around the bulge zone and also the axial loads required in the forming process. Comparison of these predictions with the experimental results shows fairly good agreement.
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Bruton, Paul. "Forming of steel polymer laminates." Thesis, Swansea University, 2001. https://cronfa.swan.ac.uk/Record/cronfa42933.
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Beglinger, Jarrod (Jarrod Thomas) 1976. "Forming of advanced composite materials." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/31077.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1998.<br>Includes bibliographical references (p. 45).<br>Two significant aspects of advanced composite material forming are examined. First, the fiber deformation of aligned fiber composites formed to double curvature parts is analyzed. Aligned fiber composite lay-ups were formed over hemispherical tools and the fiber deformation was mapped. The data were intended to support the model which predicts trellising of composite fibers in double curvature. The data are, in general, too ambiguous to clearly support this model. Second, springback of woven fiber material-single curvature parts is investigated. A 90° bend was formed for varying laminate lay-ups at varying temperatures via a double diaphragm process. Principal objectives were to qualify the effects of varying lay-ups and temperatures on the net amount of springback observed. The data show that 0/90 woven lay-ups experience more springback than either +45 degree or quasi-isotropic woven lay-ups, and that heating the laminates marginally decreases the springback experienced.<br>by Jarrod Beglinger.<br>S.B.
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Saunders, Frederick Irvin. "Forming of tailor-welded blanks /." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487858106116087.
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Kubilay, Ceylan. "Flow forming of aeroengine materials." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/flow-forming-of-aeroenginematerials(01327c19-f793-48c5-87b9-d70d3d1674ad).html.
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Flow forming is a fairly new technique used for the production of dimensionally accurate near net shaped hollow components. The process has many advantages such as cost effectiveness and eliminating further operations like welding, machining, etc. This study focuses on the characterization of flow formed components to understand the process. Flow formed components are composed of different reductions and characterization techniques are applied to reveal the resulting microstructural differences. Effect of number of passes on the material is also investigated. Metallographic analysis was conducted by optical microscope, electron micro probe analyser (EPMA) and the electron back scatter diffraction technique (EBSD) in a scanning electron microscope (SEM). Texture evolution of the samples was examined either by laboratory X-ray diffraction or EBSD technique. Furthermore, residual stresses were measured by neutron diffraction (at StrainAnalyzer for Large and Small Scale Engineering Applications (SALSA) and PulseOverlap Diffractometer (POLDI) instruments), laboratory X-ray diffraction and hole drilling. Stress relief heat treatments were carried out at 500°C for either 4 or 16 hours to mitigate residual stresses without losing much of the strength. The experiments conducted show that flow forming is a process resulting in heterogeneous microstructure with grains elongated along the deformation direction. Texture evolution is different from the typical rolling of steels with body centred cubic crystal structure. Any significant effect of the number of passes was not observed. Due to the nature of the process, residual stresses in the axial and hoop directions are critical. Therefore, stress distributions through thickness of the samples are plotted. It is observed that in the thick section, the stresses are higher. Heat treatments applied at 500°C for 4 or 16 hours are effective in diminishing the stresses.
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Silve, Sarah. "Laser forming and creative metalwork." Thesis, Bucks New University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342089.
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Lee, Pawel. "Structure in star forming regions." Thesis, University of Sheffield, 2016. http://etheses.whiterose.ac.uk/12395/.
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Stars form in clumpy, highly substructured environments. In this thesis I set up N-body simulations of substructured star forming regions and investigate the impact that the substructure has on the survival of the star forming regions. I also present a broad range of methods used in other fields to quantify and identify structure. I discuss their strengths and shortcomings and assess their suitability for use in astronomical contexts. I use the Q and Λ methods to compare the distributions of class I and class II sources in observed star forming regions to learn more about the dynamical evolution of systems and infer whether they are bound or unbound.
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Sjöstrand, Björn. "Dewatering aspects at the forming section of the paper machine : Rewetting and forming fabric structure." Licentiate thesis, Karlstads universitet, Institutionen för ingenjörs- och kemivetenskaper (from 2013), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-47640.
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The underlying motives of the research undertaken here are twofold: to obtain a deeper understanding of the dewatering mechanisms at the forming section of a papermaking machine and to develop numerical models that describe the flow through forming fabrics. More comprehensive knowledge of dewatering in the forming section allows suggestions to be made for improvements that reduce the amount of energy used in the process without affecting the quality of the end product. The objective of this thesis is to answer the following questions: How and why does rewetting occur at the high vacuum suction boxes? How does the structure of the forming fabric affect dewatering at the forming section? Is it possible to create accurate numerical models for forming fabrics, and can these be used to predict the dewatering behaviour of new types of fabrics? Laboratory and pilot studies simulating high vacuum suction boxes were performed together with numerical modelling of the flow of air and water through both the forming fabric and the paper sheet. The conclusion drawn from the pilot study is that rewetting significantly lowers the dryness of the paper sheet exiting the suction boxes. The phenomenon is extremely rapid and is most likely driven by capillary forces. The high speed at which this rewetting occurs makes it difficult to impede by placing the suction boxes closer to the couch pick-up: the solution is more likely to be the use of new and improved designs of the forming fabric. The structure of the forming fabric has been shown to affect the dewatering rate at certain conditions of vacuum dewatering, and can possibly be connected partly to the fact that fibres penetrate the surface of the fabric to varying degrees and partly to the flow resistance of the different fabric structures. Numerical models of high accuracy can be constructed and used to predetermine how new fabric designs would affect dewatering at the forming section. This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future.<br>This thesis quantifies aspects of dewatering such as rewetting and the influence of the forming fabric. Understanding these dewatering aspects further provides for the potential enhancement of energy efficiency in the forming section, and thereby the entire papermaking process. The forming fabric can play an important role in improving energy efficiency: rewetting after the high vacuum suction boxes occurs more rapidly than was previously known, so its design might be the only possible way of impeding it. The forming fabric can also improve the rate of dewatering: it is therefore likely that its design will be important in the next stage of developing energy efficiency and thereby play a part in achieving a more sustainable future.
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Grodzinsky, Mark S. (Mark Sean). "Testing a closed loop forming algorithm on a part created by discrete die stretch forming." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/40183.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.<br>Includes bibliographical references (leaves 104-105).<br>by Mark S. Grodzinsky.<br>M.Eng.
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Staněk, Michal. "Návrh tvářecího stroje pro výrobu nerezového kalíšku postupovým nástrojem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2013. http://www.nusl.cz/ntk/nusl-230630.
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My dissertation describes the procedure and results of designing a single-purpose machine, which is designed for forming a stainless metal product from an initial semi-finished product. This semi-finished product is a 0.28mm-thick stainless-steel plate. The introduction of my dissertation outlines the evolution of the pulling technology in the Czech Republic and abroad and describes its further details. This research part also includes an overview of individual machines according to the CSN. The practical part is then further dedicated to the exploration of individual issues and requirements for designing the machine itself as well as designing the machine according to the requirements of the final pulled product.
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Antoniassi, Beatriz de Souza [UNESP]. "Estudo da eletrocatálise das reações de oxidação de ácido fórmico e metanol sobre fases intermetálicas ordenadas Pt-M(M = Mn, Mo, Pb, Sb e Sn)." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/88463.
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antoniassi_bs_me_bauru.pdf: 1977733 bytes, checksum: 9dd271c973d63a540d0f517fcfe56409 (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>O grande desafio a ser vencido para a utilização de células a combustível de oxidação direta de álcoois (DAFC) refere-se ao desenvolvimento de eletrocatalisadores que favoreçam a oxidação direta do combustível a CO2 e que sejam menos susceptíveis ao envenenamento por intermediários/produtos de reação. Fases intermetálicas ordenadas de Pt têm sido propostas como materiais eletrocatalisadores para estas reações pelo fato de poderem aliar a excelente capacidade de adsorção do orgânico pelos sítios de platina e minimizarem a ação de bloqueadores superficiais. Não menos importante, essa classe de materiais apresenta uma estabilidade físico-química acentuadamente superior a materiais obtidos por deposição de íons metálicos e, desta forma, é mais apropriada para ser empregada diretamente em sistemas reais. Baseado em estudos anteriores a respeito dos materiais obtidos por deposição de íons metálicos sobre a superfície de platina e também estudos preliminares de oxidação de orgânicos em fases intermetálicas ordenadas de PtBi, este trabalho apresenta os resultados obtidos através do estudo da eletrocatálise das reações de oxidação do ácido fórmico e do metanol sobre as fases intermetálicas PtMn, PtMo, PtPb, PtSb e PtSn, em meio ácido...<br>The great challenge to be won for the use of direct oxidation of alcohols fuel cells (DAFC) refers to the electrocatalytic development that favor the direct oxidation of the fuel CO2 and that are less susceptible to the poisoning by intermediates/products of reaction. Ordered intermetallic phases of Pt have been proposed as electrocatalytic materials for these reactions for the fact of they could ally the excellent capacity of adsorption of the organic for the platinum sites and they minimize the action of blocking superficial. No less important, that class of materials presents a physicochemical stability strongly to materials obtained by deposition of metallic íons and, this way, it is more appropriate to be used directly in real systems. Based on previous studies regarding the materials obtained by deposition of metallic íons on the platinum surface and also preliminary studies of oxidation of organic in ordered intermetallic phases of PtBi, this work presents the results obtained through the study of the electrocatalysis of the reactions of oxidation of the formic acid and of the methanol on the intermetallic phases PtMn, PtMo, PtPb, PtSb and PtSn, in acid middle... (Complete abstract, click eletronic address below)