Дисертації з теми "In-Situ tensile"
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Lee, Kok Loong. "Deformation behaviour of Cu-Cr in-situ composite." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/11077.
Повний текст джерелаLind, Jonathan F. "In-situ High-Energy diffraction Microscopy Study of Zirconium Under Uni-axial Tensile Deformation." Research Showcase @ CMU, 2013. http://repository.cmu.edu/dissertations/301.
Повний текст джерелаEriksen, Lars. "Combined EBSD-Investigations and In-situ Tensile Tests of a Direct Metal Deposited Ti6Al4V-Alloy." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22438.
Повний текст джерелаWang, Wenbo. "Failure Analysis of High Nickel Alloy Steel Seal Ring Used in Turbomachinery." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6635.
Повний текст джерелаBöhm, Jochen. "In situ tensile testing at the limits of X-ray diffraction a new synchrotron-based technique." Stuttgart Max-Planck-Inst. für Metallforschung, 2004. http://deposit.d-nb.de/cgi-bin/dokserv?idn=972182810.
Повний текст джерелаGrippo, Christian P. (Christian Patrick) 1969. "Design and manufacturing of a tensile text machine for in-situ atomic force microscope mechanical testing." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/89386.
Повний текст джерелаDéprez, Pascal. "Contribution à l'étude de la forgeabilité et de la criquabilité des aciers de coulée continue." Valenciennes, 1993. https://ged.uphf.fr/nuxeo/site/esupversions/7bbe5533-fb40-4a89-a728-8816cc7f22f3.
Повний текст джерелаBabinský, Tomáš. "Rekrystalizace automatové oceli studované technikou in-situ SEM/EBSD." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378404.
Повний текст джерелаKasvayee, Keivan Amiri. "Microstructure and deformation behaviour of ductile iron under tensile loading." Licentiate thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH. Forskningsmiljö Material och tillverkning – Gjutning, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-28335.
Повний текст джерелаMathisen, Martin Borlaug. "In-Situ Tensile Testing Combined with EBSD Analysis of Ti-6Al-4V Samples from Components Fabricated by Additive Layer Manufacture." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18905.
Повний текст джерелаHasan, Mahamudul. "In-situ martensite texture evolution and phase fractions of superelastic NiTi upon tensile loading using synchrotron hard x-ray diffraction." Bochum Europ. Univ.-Verl, 2007. http://deposit.d-nb.de/cgi-bin/dokserv?id=3013895&prov=M&dok_var=1&dok_ext=htm.
Повний текст джерелаZhong, Zhengye [Verfasser]. "In situ tensile investigations on AA 7020-T6 using synchrotron diffraction for texture, lattice strain and defect density studies / Zhengye Zhong." Clausthal-Zellerfeld : Universitätsbibliothek Clausthal, 2015. http://d-nb.info/1078695237/34.
Повний текст джерелаDessolier, Thibaut. "Effet de la température sur les hétérogénéités de déformation plastique dans les alliages de magnésium." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI094/document.
Повний текст джерелаThe aim of this study is to quantify the intra and intergranular contribution of the deformation during a high temperature micromechanical test on a magnesium alloy (AZ31). In order to answer this scientific issue, we have developed an in situ tensile test at high temperature within a SEM. It has required a significant preparation work in order to push the current technical limits of this type of test on magnesium alloy. These technical limits can partly explain why there are currently few in situ studies at high temperature on magnesium alloys. A local marker in the form of a microgrid was placed on our sample as it does not provide any local contrast for digital image correlation (DIC). Before the deposition of the microgrid, EBSD mapping was made. Using the grain boundaries from the EBSD, we can superimpose the deformed grain boundaries on the strain map from the DIC.Using high temperature in-situ tensile tests, we were able to highlight the effect of the temperature on the different active deformation mechanisms. This whole development work enables us to locate the plastic deformation heterogeneities both according to the evolution of the deformation and for several temperatures. From the tests conducted, it has been shown that the higher the temperature, the more heterogeneous the plastic deformation heterogeneities are located in the vicinity of the grain boundaries. Based on a heart/coat hypothesis, we were able to quantify the intra and intergranular contribution, and show that it became more important with temperature
Sasaki, Layla. "Influence du vieillissement sur la résistance à la fissuration par fatigue à haute température d'alliages de titane pour mâts-réacteurs." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2018. http://www.theses.fr/2018ESMA0006/document.
Повний текст джерелаThe conception of more efficient aircraft engines induces increased stress and temperature levels on the titanium alloys constitutive of the engine pylon. On the one hand, these materials have to be qualified in terms of damage tolerance. On the other hand, the long term high temperature exposure of these titanium alloys gives also rise to the question of thermal aging and metallurgical stability. Hence, the dimensioning as well as the maintenance of such aerostructures need to be considered in the light of both these critical issues.In the present work, the cyclic behavior as well as the fatigue crack resistance of different titanium alloys (TA6V, Ti 6242 et Ti 17), with various microstructures were studied after different aging conditions. Aging induces mainly an increase in crack growth rates at high values of the stress intensity factor, at room temperature. Subsequently, a thorough characterization procedure of this phenomenon was undertaken,including various types of loadings, at different scales and associated with fractographic analyses. The results allowed to suggest a damage scenario before and after aging, in the case of the alloy most affected by aging: theTi 17 alloy. This scenario shows the occurrence of a « static » mode of failure, which is linked to a damage process associated with intralamellar fracture and decohesion, without noticeable changes in the cyclic behavior. Finally, a time-temperature equivalency approach was developed to describe the kinetics of degradation of the mechanical properties induced by aging
Willeman, Héloïse. "Multi-scale characterization of deformation mechanisms of poly-ether-ether-ketone (PEEK) under tensile stretching." Electronic Thesis or Diss., Lyon, INSA, 2023. http://www.theses.fr/2023ISAL0006.
Повний текст джерелаThe aim of this PhD work is accessing the microscopic deformation mechanisms of bulk poly-ether-ether-ketone (PEEK) under tensile stretching. Beforehand, the thermal and mechanical properties of two commercial grades of PEEK were characterized. Tensile specimens were then compression-molded to obtain morphologies as isotropic as possible and characterized below and above the glass transition temperature. Deformations at the scales of lamellar stacks and of the crystalline unit cell have been characterized by small and wide-angle X-ray scattering (SAXS and WAXS) performed in-situ during tensile tests. Simultaneously, the strain field within the samples was followed by digital image correlation (DIC) in order to compare microscopic and macroscopic strains. At both temperatures, lamellae tend to orient perpendicular to the tensile direction (TD). This orientation mechanism (which we denote as ‘Chain Network model’) is driven by the amorphous chains which transmit the stress between adjacent lamellae. The tensile strain in lamellar stacks perpendicular to TD is lower than the macroscopic tensile strain, which must be compensated by increased shear in inclined stacks. Some differences of behavior have been observed depending on the test temperature, especially at high deformation. A highly oriented morphology is ultimately obtained in all cases. However, the central scattering profiles changes with testing temperatures. Below Tg, the presence of small entities randomly oriented is indicated. Above Tg, the material is fibrillar and contains cavities
Pinto, Cristiane Franco. "Analise da união e dos tecidos dentais (esmalte/dentina) adjacentes as restaurações com sistemas adesivos contendo fluoreto apos desafios cariogenicos in situ e in vitro." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287811.
Повний текст джерелаTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo deste estudo foi avaliar sistemas adesivos, tecidos dentais adjacentes (esmalte ou dentina) às restaurações e a união formada entre os adesivos e as estruturas dentais frente aos desafios cariogênicos in situ e in vitro. Para o estudo foram utilizados dentes bovinos e blocos dos tecidos dentais (esmalte e dentina) que foram restaurados com dois sistemas adesivos e resina composta. No estudo in situ; 11 voluntários utilizaram dispositivos palatinos contendo 2 amostras do grupo controle (substrato hígido sem preparo cavitário) de esmalte e dentina, e 6 amostras restauradas com os sistemas adesivos Clearfil Protect Bond (PB) ou One-Up Bond F Plus (OP) (em fases distintas) e com o compósito Filtek Z350. O desafio cariogênico consistiu de 2 fases (cada fase com um adesivo), sendo cada fase de 14 dias com intervalo de 10 dias entre elas. Os voluntários utilizaram solução de sacarose a 20%, 8X/dia e dentifrício fluoretado 3X/dia. Após cada etapa, o biofilme dental formado foi coletado e analisado. As amostras foram analisadas através de Microscopia de Luz Polarizada (MLP) e Microdureza Knoop para observação da extensão da lesão de cárie. Para o estudo in vitro foi realizado o preparo dos substratos e foram restaurados em esmalte e em dentina seguindo os grupos experimentais: 1-adesivo PB sem desafio cariogênico (DC); 2- adesivo PB com DC; 3- adesivo OP sem DC; 4- adesivo OP com DC. A partir dos blocos dentais restaurados foram obtidos espécimes para o ensaio de resistência da união com formato de paralelepípedos (palitos) e fatias para análise da interface da união em Microscopia Eletrônica de Transmissão (MET). Os espécimes (palitos ou fatias) foram submetidos à ciclagem de pH durante 8 dias. O resultado do ensaio de microdureza em esmalte e dentina mostrou maiores valores para PB nas profundidades mais superficiais e as imagens de MLP mostraram uma menor extensão da área de desmineralização para o adesivo PB que para o adesivo OP. Na análise bacteriológica, o adesivo PB levou a menor quantidade de colônias de Streptococcus totais e do grupo mutans em esmalte. A resistência de união não foi afetada pela ciclagem de pH e foi semelhante em esmalte para ambos adesivos, entretanto, em dentina, o adesivo PB apresentou maior resistência de união que o adesivo OP. Os adesivos produziram hibridização nos tecidos dentais, sem formações de fendas na interface de união. Concluiu-se que o adesivo PB produziu menor extensão de desmineralização dos substratos dentais após o desafio cariogênico e maior microdureza Knoop nas profundidades mais superficiais. Em algumas condições deste estudo, o adesivo PB reduziu a formações de colônias bacterianas. Embora a união formada pelos adesivos em esmalte foi semelhante, o adesivo PB mostrou maior resistência de união em dentina.
Abstract: The aim of this study was to evaluate adhesive systems, mineralized dental tissues (enamel and dentin) around restorations and the bonding formed by adhesives and dental structures in conditions of cariogenic challenge in situ and in vitro. This study used dental blocks (enamel/ dentin) from bovine teeth, which were restored with adhesive systems and a resin composite. For the in situ study: volunteers (n=11) wore intra-oral appliance containing 2 dental fragments without restoration (enamel or dentin) and six dental blocks with restorations made with self-etching primers Clearfil Protect Bond (PB) or One-up Bond F Plus (OP) (in two phases) and the Filtek Z350 composite: The cariogênico challenge was performed in two phases of 14 days (each phase with one adhesive). The volunteers dropped 20% sucrose solution 8x/day and used fluoridated dentifrice 3x/day. After each phase, the biofilm was collected and analyzed. The samples were analyzed by cross-sectional microhardness and polarized light microscopy (PLM) to determine the demineralization depth. For the in vitro study, bovine were prepared and bonded in enamel and dentine with Clearfil Protect Bond (PB) or One-Up Bond F Plus (OP) and restored with Filtek Z-350 composite resin, according to the groups: 1- PB without CC; 2- PB with CC; 3- OP without CC; 4- OP with CC. Restored teeth were sectioned in order to obtain sticks for microtensile bond strength or slabs for transmission electron microscopy. The specimens were submitted to pHcycling, which consisted of DE (8h/day) and RE (16h/day) cycles at 37ºC during days. Microhardness analysis showed that the enamel and dentin around restorations PB had higher values in superficial depths, and the PLM showed that PB resulted in lower demineralization depth than OP. The biofilm investigation indicated that PB produced lower number of bacterial colony of Streptococcus totais and mutans in enamel. The results showed that the pH-cycling regimen did not affect the bond strength to enamel or dentin for both adhesives; however, the bond strength to dentin was higher for PB. The adhesives produced hybridization and no gaps formation in both dental tissues. In conclusion, PB adhesive may result in lower enamel demineralization around restoration and higher microhardness in superficial depths. In some conditions, PB adhesive reduced the number of bacterial colony. Although the adhesives in enamel formed similar bonded interfaces, PB produced higher bond strength to dentin than OP.
Doutorado
Dentística
Doutor em Clínica Odontológica
Tahir, Muhammad. "Development of Novel Blends based on Rubber and in-situ Synthesized Polyurethane-urea." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-232718.
Повний текст джерелаMillot, Coraline. "Multi-scale characterization of deformation mechanisms of bulk polyamide 6 under tensile stretching below and above the glass transition." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0028/document.
Повний текст джерелаMechanical properties of bulk polyamide 6 (PA6) have been studied in relation to microscopic deformation mechanisms. By applying various thermal treatments, sets of samples with different semi-crystalline microstructures, namely various crystalline allotropic forms (denoted α, γ and β) and different values of the crystallinity index (from 24 to 35%) and of the long period of the lamellar stacks (from 7 to 12 nm), have been obtained, for two different molecular masses. Mechanical properties have been measured in the linear (viscoelastic) and nonlinear (plastic) regimes below and above the glass transition of the amorphous phase (Tg). Differences of behavior have been observed depending on the microstructure. While the crystallinity index seems to be the predominant factor affecting the mechanical behavior above Tg, other structural parameters such as the crystalline form and the lamellar morphology (thickness and aspect ratio) have to be taken into account below Tg. Deformations at the scales of lamellar stacks and of the crystalline unit cell have been characterized by small and wide angle X-ray scattering (SAXS and WAXS) performed in-situ during tensile tests. In samples with predominantly β phase, lamellae tend to orient perpendicular to the tensile direction (TD). This orientation mechanism (which we denote as ‘Chain Network model’) is driven by the amorphous chains which transmit the stress between adjacent lamellae. The tensile strain in lamellar stacks perpendicular to TD is lower than the macroscopic tensile strain, which must be compensated by increased shear in inclined stacks. Also, at high extension ratios, the β phase transforms into α phase. In samples with predominantly α phase and above Tg, morphology changes are more complex. In a first step, chains orient perpendicular to TD, which implies that lamellar planes tend to orient parallel to TD, possibly due to their high aspect ratio (denoted as ‘Rigid Lamella’ model). In a second step, beyond the yield, a major fraction of crystallites then reorients normal to TD, i.e. chains themselves become parallel to TD, while a minor fraction remains oriented along TD. A highly oriented fibrillar morphology is ultimately obtained in all cases
Pazat, Alice. "Chemical Modification of Graphite-based Derivates and Their Uses in Elastomer Nanocomposites." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1050/document.
Повний текст джерелаThe aim of this study was the investigation of various dispersion methods for graphite-based fillers in elastomers such as polyisoprene, to enhance mechanical and barrier properties. To increase graphite-rubber interactions and so decrease filler-filler aggregation, graphite-based fillers have been chemically modified. Graphite was previously oxidized into graphite oxide (GO), bearing epoxide, hydroxyl and carboxylic acid groups, which could further act as anchor sites for molecules and polymer chains. To increase the compatibility between GO and the polymeric matrix, amines and alkoxysilanes, as well as polymer chains, were grafted on GO. Grafting contents between 4-50 wt% were obtained, depending on the functionalization technique which was used. A thermal modification path of GO was also investigated and led to the formation of porous graphite structure. Polyisoprene composites containing 15 phr of these graphite-based fillers were prepared and showed decreased air permeability (-70 % for composites containing thermally-treated graphite filler, as compared to those containing carbon black only) as well as enhanced tensile properties. Finally, the use of ionic liquids as dispersing agents was investigated. Natural rubber – graphite composites with 1 wt% of ionic liquid displayed enhanced reinforcement (+ 25 % for the stress at 300 % strain) while maintaining similar strain at break to composites containing carbon black only
Böhm, Jochen [Verfasser]. "In situ tensile testing at the limits of X-ray diffraction : a new synchrotron-based technique / Institut für Metallkunde der Universität Stuttgart ... Vorgelegt von Jochen Böhm." Stuttgart : Max-Planck-Inst. für Metallforschung, 2004. http://d-nb.info/972182810/34.
Повний текст джерелаPushkareva, Marina. "Study of Void Growth in Commercially Pure Titanium." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35667.
Повний текст джерелаSaraiva, Letícia Oliveira. "Influência da umidade e temperatura intrabucais na resistência de união de sistemas adesivos convencionais de dois passos à dentina : estudo in situ." Programa de Pós- Graduação em Odontologia da UFBA, 2008. http://www.repositorio.ufba.br/ri/handle/ri/11031.
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O presente estudo teve como objetivos avaliar o efeito das condições de temperatura e umidade relativa intrabucais na resistência de união à dentina de dois sistemas adesivos convencionais de dois passos (Single Bond 2/SB2 e One Step Plus/OSP), e avaliar a umidade e a temperatura presentes nas regiões de incisivos e molares superiores. Sessenta fragmentos dentários foram esterilizados, fixados em moldeiras de acetato individualizadas, e posicionados in situ em um voluntário para serem restaurados com resina composta, sendo aleatoriamente divididos em seis grupos, de acordo com o sistema adesivo e com a condição de temperatura e umidade: G1 – SB2 na condição ambiental de um consultório odontológico; G2 – SB2 na condição da região de incisivos; G3 – SB2 na condição da região de molares; G4 – OSP na condição ambiental de um consultório odontológico; G5 – OSP na condição da região de incisivos e G6 – OSP na condição da região de molares. Em todas as condições, foram obtidas e registradas a temperatura e a umidade relativa do ar no momento e no local em que as restaurações foram produzidas, usando um termo-higrômetro digital. Após ensaio de microtração, os dados do teste de resistência de união foram submetidos à análise estatística (ANOVA - 2 fatores/ Teste de Tukey, α=5%) e os valores médios em MPa foram: G1 = 20,2 (7,6); G2 = 23,0 (6,5); G3 = 22,7 (6,0); G4 = 29,0 (5,8); G5 = 29,7 (4,9) e G6 = 27,7 (4,8). Os resultados demonstraram que os grupos que utilizaram o OSP (G4, G5 e G6) apresentaram médias semelhantes entre si (p=0,67) e maiores do que os grupos que utilizaram o SB2 (G1, G2 e G3) (p=0,001), também semelhantes entre si (p=0,67). Foi observado que as condições de temperatura presentes nas regiões intrabucais (incisivos e molares) foram semelhantes entre si, e maiores que a condição ambiental do consultório odontológico. A condição de umidade na região de molares foi superior à condição na região de incisivos, e esta foi maior do que a condição presente no ambiente do consultório odontológico. As condições de temperatura e umidade intrabucais não influenciaram a resistência de união dos sistemas adesivos simplificados à dentina. O sistema adesivo One Step Plus apresentou melhores resultados que o sistema Single Bond 2, independentemente das condições de umidade e temperatura.
Salvador
Ehsan, Dina. "Stress-free titanium-based thin films for inner ear microphones : The last missing part of a technology for totally implantable hearing aid implants." Thesis, Linköpings universitet, Tunnfilmsfysik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-169705.
Повний текст джерелаZaragoci, Jean-François. "Simulation numérique directe multiphasique de la déformation d’un alliage Al-Cu à l’état pâteux – Comparaison avec des observations par tomographie aux rayons X in situ en temps réel." Thesis, Paris, ENMP, 2012. http://www.theses.fr/2012ENMP0088/document.
Повний текст джерелаHot tearing is a major defect arising during solidification of aluminium alloys. This defect is associated with the inability of liquid to feed areas where voids have started to appear, not allowing to heal small defects before they grow bigger. To understand hot tearing, it is mandatory to develop a good knowledge of the semi-solid mechanical behaviour. It is thus very useful to carry out X-ray microtomographies experiments and mechanical simulations on representative elementary volumes. In this work, we couple the both approaches by initialising a finite element simulation with the help of microtomography data obtained during an isothermal tensile testing of an aluminium-copper alloy in the mushy state. This innovative approach gives a direct access to the experimental reality and allows comparisons of numerical and experimental evolutions of the sample. We explain in a first time how to get the numerical representation thanks to a marching cubes algorithm and the immersed volume method. Then, we present our numerical model for which we solve the Stokes equations in a monolithic way. Once the velocity computed in all the solid, liquid and gaseous phases, we use a level set method in a Eulerian formalism to obtain the morphological evolution of our numerical sample. Despite the model simplicity, numerical and experimental results show a reasonable agreement concerning the air propagation inside the sample
Cristofari, François. "Etude du comportement et de la résistance mécanique d'un pancréas bioartificiel pour l'homme. Caractérisation expérimentale et simulation numérique." Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0055.
Повний текст джерелаIn order to treat type 1 diabetics, a bioartificial pancreas has been developed. It consists in the encapsulation of insulin producing cells: it is made of porous membranes which isolate cells from patient antibodies, allowing the glucose and the insulin to pass through. Before its commercialization, it is necessary to verify that its mechanical behavior allows it to be implanted in a human body without any risk for the patient. The mechanical strength of the membranes under loading is therefore studied. Their structure is first obtained using scanning electron microscopy and X-ray nanotomography. Tensile tests are then done at both macroscopic and microscopic scales, digital image correlation techniques being used to characterize the membranes at each scale. At the same time, a numerical model using finite element method is built based on the microstructural and mechanical characteristics of the membranes experimentally identified. A methodology to compare the experimental and numerical results behavior of the membranes is proposed and used. The results of the study are finally considered to assess the possibility to use the device in clinic phase
Bo, Arixin. "Investigation of the mechanical and electron interaction properties of layered titanate nanowires." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/105649/4/Arixin_Bo_Thesis.pdf.
Повний текст джерелаLin, Sen. "Deformation-Induced Martensitic Transformation and Mechanical Properties of Duplex and Austenitic Stainless Steels : A Synchrotron X-Ray Diffraction Study." Thesis, KTH, Metallografi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-233334.
Повний текст джерелаHägerström, Helene. "Polymer Gels as Pharmaceutical Dosage Forms : Rheological Performance and Physicochemical Interactions at the Gel-Mucus Interface for Formulations Intended for Mucosal Drug Delivery." Doctoral thesis, Uppsala University, Department of Pharmacy, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3538.
Повний текст джерелаDrug delivery to the nasal and ocular mucosa faces several obstacles. One of these is from the effective clearance mechanisms present in the nose and eye. Polymer gels with suitable rheological properties can facilitate the absorption of poorly absorbed drugs by increasing the contact time of the drug with the mucosa. This has been attributed to the rheological and mucoadhesive properties of the gel. The main objective of this thesis was to investigate the importance of these features for the anticipated in vivo contact time, here exemplified by the ocular and nasal routes of administration.
The in situ gelling polymer gellan gum was found to have a favourable rheological and in vivo performance. When administered in the nasal cavity of rats, a gel was formed that could remain at the site of administration for up to 4 hours. In addition, the epithelial uptake and transfer of a 3 kDa fluorescein dextran was higher than for a mannitol solution. Therefore, it was concluded that a gellan gum formulation should be a promising strategy for nasal drug delivery.
The potential mucoadhesive properties of a variety of polymer gels were investigated using a rheological method and by measuring the tensile force required to detach the gel from a mucosa. With both methods the rheological properties of the gel were a determining factor for the results obtained. The rheological method was found to have several limitations. One of these was that a positive response, interpreted as mucoadhesion, was only seen with weak gels. The tensile method could, in contrast, detect strengthening of the mucus only for strong gels. However, this method reflects the in vivo performance of the gel better than the rheological method.
Finally, dielectric spectroscopy was explored as a tool for investigating the likelihood of intimate surface contact between the gel and the mucus layer. This novel approach involved determining the ease with which a charged particle can pass the gel-mucus interface layer, and may enable the study of the events at the interface closer to the molecular level, than is possible with the rheological and tensile strength methods.
Chaudemanche, Samuel. "Caractérisation in situ de l'endommagement volumique par Spectroscopie Raman et rayons X de différents polypropylènes déformés en traction uniaxiale." Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0263/document.
Повний текст джерелаThe use of polymer materials - replacing or combining with metallic materials - has successfully established itself in the 20th century for increasingly technical mechanical applications. The great diversity of polymers physical properties is closely related to their high microstructural complexity, which is still very misunderstood despite their massive use. The development of new techniques for in situ characterization allows to better understand the microstructural evolutions on nanoscale and micrometer scale which affect the macroscopic behavior. This work report the use of Raman spectroscopy coupled with the VideoTractionTM system in order to obtain information about the microstructural deformation of polymer. Various formulations of polypropylene were studied to highlight the role played by the polypropylene matrix and the organic and mineral fillers in the plastic deformation process. The in situ measures of the macromolecular chains' orientation determined by Raman were confirmed by the performing of an experimental setup coupling the Raman-VideoTractionTM system with a device of Wide angle X-ray scattering. The volume damage of material was studied post mortem using X-ray tomography. The improvements made to VideoTractionTM-Raman system and a study of the incoherent light scattering of our materials enabled the setting of a Raman criterion for measuring in situ the volume damage. The studies carried out to evaluate in situ macromolecular orientation and volume damage highlight the existence of competition between these two processes. The degree of influence of organic and mineral fillers in this competition within the polypropylene matrix was determined
Ben, Hafsia Khaoula. "Identification des micro-mécanismes de déformation du PET amorphe et semi-cristallin in situ au cours d’un essai mécanique." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0081/document.
Повний текст джерелаAccording to their formulations and forming processes and thanks to the complexity of their induced microstructure, thermoplastic polymers show a wide range of thermomechanical properties. However, the identification of the evolution of the microstructure of these materials during their use remains difficult. To better understand the microstructural changes occurring during thermomechanical loadings, various in situ and non-destructive techniques of characterization have been used. In this context, a Poly (Ethylene Terephthalate) (PET) amorphous and semi-crystalline was studied in order to highlight the effect of the microstructure on the macroscopic properties of the material. This way, different coupling systems combining several experimental characterization techniques have been implemented such as Raman spectroscopy and X-rays diffraction/scattering coupled to the VidéoTraction™ system or Raman spectroscopy coupled with differential scanning calorimetry (DSC) for the characterization of the deformation micro-mechanisms and the thermal behavior of the material respectively. Monitoring specific vibrational bands thoroughly identified allowed the establishment of a new robust criterion which enables to accurately measure the crystallinity ratio of the material and the identification of the characteristic temperatures of its morphology (Tg, Tc, Tcc, Tm). In addition, a relaxational characterization system by coupling dynamic dielectric spectroscopy to a tensile test has been used in order to highlight the effect of molecular mobility on the elasto-visco-plastic deformation of PET. From a mechanical point of view, the main deformation micro-mechanisms have been studied in real time during a tensile test at different temperatures and constant true strain rates: macromolecular orientation, volume damage, development of mesophase and strain induced crystallization were observed and quantified in situ using the coupled characterization technics presented previously at Petra III (Hambourg) and Elettra (Trieste) synchrotrons. In parallel, a study of the molecular mobility (a determining parameter for the predominance of one deformation micromechanism to another) was conducted via relaxational analysis performed during the deformation of the material. In addition to in situ experiments, post mortem analysis by the previously mentioned technics and by X radiography, scanning electron microscopy and X tomography were performed to assess the influence of the mechanical relaxation of the polymer
Ben, Ramdane Camélia. "Etude et modélisation du comportement mécanique de CMC oxyde/oxyde." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0077/document.
Повний текст джерелаOxide/oxide CMCs are good candidates for thermostructural applications. Themechanical behaviour and damage mechanisms of two alumina/alumina composites with two andthree dimensional woven reinforcements were studied and compared. The microstructure of theseweak matrix CMCs was characterized by porosimetry and NDT methods, such as IR thermography,ultrasound scanning and X-ray tomography, which highlighted initial defects. The mechanicalbehaviour was studied through tensile tests, as well as compression tests in the case of the twodimensionalreinforced CMC. These tests were conducted at room temperature, in the fibres directionsand in the ±45° direction. In order to fully exploit these tests, several extensometry and damagemonitoring methods, such as IR thermography and acoustic emission, were used. Young’s moduli andmaximum stresses and strains of the two-dimensional reinforced CMC developed at Onera appearedto be higher than those available in the literature. The damage mechanisms of the materials weredetermined by post mortem SEM observations and in situ testing in a SEM, which made it possible toassess the nocivity of initial defects. Studying the mechanical behaviour of these composites finallyenabled the development of a three-dimensional damage model that will facilitate the furtherdevelopment of such materials, through finite element analysis. Finally, some improvements regardingthe manufacturing processes and the instrumentation for damage monitoring were suggested forfuture studies
Kasvayee, Keivan Amiri. "On the deformation behavior and cracking of ductile iron; effect of microstructure." Doctoral thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Material och tillverkning, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-36852.
Повний текст джерелаDenna avhandling fokuserar på effekten av variationer i mikrostrukturen på mekaniska egenskaper och deformationsbeteende hos segjärn. För att undersöka dessa effekter, två olika sorter av segjärn, (i) GJS-500-7 och (ii) högkisellegerad GJS-500-14, gjutits till plattor av olika tjocklekar för att generera mikrostrukturvariationen. Mikrostrukturundersökning, samt drag- och hårdhetsprov gjordes på de gjutna plattorna. Resultaten visade att en högre ferritfraktion, grafitpartikelantal och sträckgräns i den högkisellegerade GJS-500-14-sorten jämfört med GJS-500-7. För att studera förhållandet mellan mikrostrukturell variation och spännings-töjningsbeteendet på makroskala, modellerades detta med hjälp av Ludwigson-ekvationen. De erhållna spännings-töjningsegenskaperna modellerades baserat på mikrostrukturell karaktäristika genom multipel linjärregression och variansanalys (ANOVA). Modellerna visade att kiselhalt, grafitpartikelantal, ferritfraktion och porfraktion var de viktigaste bidragande faktorerna. Modellerna implementerades i ett simuleringsprogram för gjutningsprocessen. Resultatet från simuleringen validerades med hjälp av experimentella data som inte ingick i underlaget för regressionsanalysen. Detta möjliggjorde att prediktera spännings-töjningsbeteendet och dess variation hos gjutna segjärns komponenter med liknande sammansättning och gjutna tjocklekar som användes i denna studie. För att kunna undersöka deformationsbeteendet på mikroskala utvecklades en metod för kvantitativ mätning av töjning i mikrostrukturen, genom DIC-tekniken (digital image correlation) tillsammans med in-situ dragprovning. I denna metod utvecklades en grop-etsningsprocess för att generera ett slumpvis prickmönster, vilket möjliggjorde DIC-töjningsmätning i matrisen och i området mellan grafitpartiklarna med tillräcklig upplösning. Metoden validerades genom benchmarking av den uppmätta sträckgränsen mot materialets makroskopiska sträckgräns mätt med konventionell dragprovning. Det mikrostrukturella deformationsbeteendet under dragbelastning karakteriserades. Under elastisk deformation avslöjade töjningsmönstret en heterogen töjningsfördelning i mikrostrukturen, och bildandet av skjuvband mellan grafitpartiklar. Sprickbildning initierades vid låg spänning och redan vid de spänningsnivåer som ligger vis ”knät” på dragprovningskurvan, vilket indikerar energidissipering genom både begynnande plastisk deformation och sprickbildning. Den lokala töjningen vis sprickinitiering skedde då den lokala töjningen översteg 2%, vilket indikerar att detta skulle kunna vara en tröskelnivå för den töjning som erfordras för initiering av mikro-sprickor. En kontinuum Finita Element (FE) modell utvecklades för att prediktera töjningen hos ett segjärn och dess fördelning i segjärns mikrostruktur. Materialparametrarna för denna modell optimerades genom att anpassa parametrarna i Ramberg-Osgood ekvationen. De predikterade töjningsfördelningarna jämfördes med de experimentell uppmätta töjningsmönstren uppmätta med DIC, både kvalitativt och kvantitativt. Töjningsmönstren överensstämde i stor utsträckning, vilket resulterade i att modellerna kunde anses vara validerade på mikronivå. För att kunna mäta töjningsmönster under dynamiska förlopp på mikronivå utvecklades en metod för att skapa prickmönster och att utföra in-situ CT provning i ett svepeletronmikroskop (SEM). Prickmönstret skapades genom avverkning med en fokuserad jonstråle (FIB), och provades på det ferritiska segjärnet (GJS-500-14 grad). Resultaten visade att maximal töjningskoncentration fanns i närheten av mikrosprickorna, framförallt framför sprickspetsen.
Barke, Derek Woolrich 1975. "An in situ test for stress corrosion damage and tension in bolts." Monash University, Dept. of Mechanical Engineering, 2002. http://arrow.monash.edu.au/hdl/1959.1/7686.
Повний текст джерелаJousse, Florie. "Processus physico-chimiques à l'origine des différences d'efficacité des techniques de traitement de sols pollués aux hydrocarbures." Thesis, Bordeaux 3, 2016. http://www.theses.fr/2016BOR30030/document.
Повний текст джерелаPollution of soils and aquifers by Diesel fuel compounds is a widespread remediation issue. Problems due to soil remediation are more and more difficult to treat. Hydrocarbons are often encountered. But they are known for their toxicity and increased persistence. The establishment of effective remediation methods is paramount. Conventional methods require excavation or pumping contaminated areas requiring a high abatement costs. That is why, in-situ remediation techniques have been developed to reduce these costs while ensuring efficient pollution control returns. The work done during this thesis has determined for several treatments, the limiting factors inherent the treatment, but also quantifies the role of contact between agents and pollutants or density effects. In-situ treatments are: in situ chemical oxidation, surfactants flushing, air sparging and thermic treatment. Three levels of experience were investigated: batch, column and 3D Pilot. Batchs, enabled the comparison of oxidants in sand and natural soil. The columns have highlighted the influence of the injection method applied occurs toward the physical and chemical properties of contaminants (reaction kinetics, vapor pressure, boiling temperature, etc.). 3D Pilot, have a volume of 1m3. They were used to compare the different treatments on a heterogeneous medium having low permeability zones, difficult to treat. From the results of numerical modeling and experiences, it is possible to adjust the treatment method and especially to compare different methods for a given hydrogeological context
Khosravani, Ali. "Application of High Resolution Electron Backscatter Diffraction(HR-EBSD) Techniques to Twinning Deformation Mechanism in AZ31 Magnesium Alloy." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3432.
Повний текст джерелаHutin, Anthony. "Interactions entre molécules amphiphiles in situ et tensioactifs synthétiques pour la récupération d'huile réactive." Paris 6, 2013. http://www.theses.fr/2013PA066395.
Повний текст джерелаThis work deals with the understanding of interactions between in situ (or indigenous) surfactants and added synthetic surfactants for Enhanced Oil Recovery (EOR). Heavy crude oils contain amphiphilic moclécules, such as asphaltenes and naphthenic acids, wich ar natural surfactants. Durinf an EOR operation, pH influences the ionization of acidic and/or basic species of crude oil making thm more hydrophylic that inscreases their affinity for the interface. In this study, we showed that there is a strong interaction between a sulfonated anionic surfactant (SDBS) and in situ surfactant of an acidic heavy oil. Ultra-low interfacial tensions (<10-3 mN/m) were obtained at pH 11 with a small addition of SDBS (~0,05 wt%). Different dynamics of interfacial tensions were measured in the presence of SDBS for extreme pH with significant transient effects. These are the result of transfers of molecules from crude oil to water. Mass transferrs of amphiphilic molecules from crude oil were highlighted by measuring the pH of the aqueous phase in contact with crude oil. Without SDNS, crude oil act as an acid oil with the transfer of acids at basic pH. In the presence of SDBS, we also observe the transfer of bases of crude oil at acidic pH. Taking into account the acid-base behavior of crude oil, we developed a model to predict the evolution of the final pH of an aqueous solution in contact with an acid-base oil according to different parameters (acidity, pka,. . . )
Pinho, Marco André de Berredo. "Efetividade in situ do Chlor-Xtra na dissolução do tecido pulpar em canais radiculares ovais." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=6694.
Повний текст джерелаSodium hypochlorite solutions with added wetting agents are advertised to dissolve necrotic tissue in root canals faster than counterparts without lowered surface tension. This was tested in the current study using extracted, single-rooted teeth with oval canals that contained pulp tissue. Formerly vital extracted teeth (N = 44) with similar anatomy were radiographically paired and chemomechanically prepared. In one tooth, a 5.25% NaOCl solution with reduced surface tension was used, in the other a pure, technical-grade NaOCl solution of 5.25%. Percentage of remaining pulp tissue (PRPT) was histologically assessed in root cross-sections. The non-Gaussian raw data was subjected to Kruskal-Walis and Mann-Whitney U tests to verify the respective effect of level of cross-section and solution on the PRPT.The relationship between level of cross-section and PRPT was estimated by Spearman correlation test. Alpha-type error was set at 5%. The level of section significantly influenced the PRPT (P<0.05), whereas the PRPT was not influenced by the solution used (P>0.05). A significant inverse correlation was found between the level of section and PRPT (P<0.05, r = -0.330). The lower the distance to the apex, the higher the PRPT, regardless of the solution used.Contrary to the advertised statement, the dental solution with reduced surface tension did not dissolve vital pulp tissue in oval root canals any better than a conventional NaOCl solution of similar strength. Closer to the apex, pulp tissue dissolution is less efficient, irrespective of the solution.
Djeridi, Ikram. "Biodégradation des Hydrocarbures en milieux hypersalins : modes de transferts et réponses des communautés procaryotiques à une contamination pétrolière." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4053.
Повний текст джерелаThe fate of hydrocarbons (HC) in hypersaline environments is an important environmental issue. This work aimed to (1) assess the impact of oil pollution on microbial communities of a hypersaline environment, (2) determine how hydrocarbonoclastic archaea can access to HC and (3) whether biodegradation is possible in these hypersaline environments in the absence of oxygen. We have shown that moderate oil biodegradation is possible under hypersaline conditions. In these conditions close to natural ones, about 10% of the aliphatic hydrocarbons were biodegrade. A gradual disappearance of the lighter aromatic compounds was also observed, but these losses were mainly due to abiotic processes. The monitoring of prokaryotic communities based on molecular fingerprints showed a change in the structure of the indigenous bacterial community. On the contrary, resistance to oil contamination was observed among the indigenous archaeal communities of brines. In the second part of this work, laboratory cultures of a hyperhalophilic archaeal strain (Haloferax volcanii MSCN14), allowed to demonstrate that, in hypersaline environments, hydrocarbonoclastic archaea use several strategies to increase the bioavailability of HC. Indeed, strain MSCN14 was capable of producing one or several biosurfactants during growth on different HC, and was adhering to the surface of the HC. In the last part of this work, we tested the capacities of a model archaeal strain (Hfx. volcanii MSNC 16) to degrade HC anaerobically. If Hfx. volcanii MSNC16 was able to use fumarate as a terminal electron acceptor, it was, however, not capable of degrading heptadecane in the absence of oxygen
Venturi, Linda. "Etude des propriétés de photoluminescence de nano-matériaux sous champ électrique intense." Thesis, Normandie, 2019. http://www.theses.fr/2019NORMR118.
Повний текст джерелаIn this thesis, the Laser-assisted Atom Probe Tomography is coupled in-situ with a photoluminescence (PL) bench, where the pulsed laser radiation is used to trigger the ion evaporation from the specimens and, simultaneously, to activate the emission from optically active centers present into the material. For this work, two different materials were selected: diamond nano-needles with embed- ded optically active defects (color centers) and a ZnO/(Mg,Zn)O multi-quantum-well (MQW) heterostructure, which contains quantum emitters of different thicknesses. Thanks to this original photoluminescence setup, the influence of the electric field on the fine structure of some color centers, embedded into the diamond nanoneedles, was observed. The first study focused on the neutral nitrogen-vacancy center (NV0), which is one among the most studied color centers in literature. The evolution of the NV0 optical signature, as a function of the applied bias, allowed to evaluate the mechanical stress (> 1 GPa) and the electric-field acting on diamond tips. These results demon- strate an original new method to perform contactless piezo-spectroscopy of nanoscale systems under uniaxial tensile stress, generated by the electric field. This method was applied also on another color center, which nature is still not clear in literature, emitting at 2.65 eV, and more sensitive than the NV0 color centers to the stress/strain field. New results on its opto-mechanical properties were obtained, but its identity still needs to be understood. Since the evaporation field of diamond is really high, the diamond nanoneedles were not analyzed using La-APT. Therefore the coupled in-situ technique was applied in order to study the ZnO/(Mg,Zn)O MQW heterostructure, accessing to the structure, composition and optical signature of the probed specimen in only one experiment. The photoluminescence spectra acquired by the specimen during its ongoing evaporation represents a unique source of information for the understanding of the mechanism of light-matter interaction and the physics of photoemission under high electric field. The correlation of the structural and optical information, related to this MQW heterostructure, demonstrates that the coupled in-situ technique can overlap the diffraction limit of the PL laser and that, as done for the diamond nanoneedles, is pos- sible to estimate the induced-tensile-stress. The results achieved by the in-situ coupling of the La-APT technique with the PL spec- troscopy show that such instrument is an innovative and powerful technique to perform research at the nanometric scale. For this reason, this work can open new perspectives for a deeply understanding of the physicics related to the studied systems in parallel with the continuous enhancement of the experimental setup
Park, Janghoon, Hyi Jae Kang, Hyogeun Gil, Kee-Hyun Shina, and Hyunkyoo Kang. "Roll-to-roll infrared and hot-air sintering of gravure-printed Ag layer based on in situ tension measuring and analysis." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-222812.
Повний текст джерелаDieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
Shaoguang, Chen. "Experimental Investigation on Mechanical Properties of Nanospring Thin Films Fabricated by Glancing Angle Deposition Technique." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225556.
Повний текст джерелаGuérin, Jean-Dominique. "Analyse des essais de compression et de traction des aciers après solidification in situ et des essais d'indentation des aciers phosphatés." Valenciennes, 1993. https://ged.uphf.fr/nuxeo/site/esupversions/b769f69b-4777-454d-94ad-c3bac6b6fab1.
Повний текст джерелаOrnek, Cem. "Performance characterisation of duplex stainless steel in nuclear waste storage environment." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/performance-characterisation-of-duplex-stainless-steel-in-nuclear-waste-storage-environment(4db73e9b-c87c-40a6-9778-0b823b1c499f).html.
Повний текст джерелаRATHOD, CHANDRASEN. "DIFFRACTION STUDIES OF DEFORMATION IN SHAPE MEMORY ALLOYS AND SELECTED ENGINEERING COMPONENTS." Doctoral diss., University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2892.
Повний текст джерелаPh.D.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Materials Science and Engineering
Fnaiech, Mustapha. "Contribution a l'etude "in situ" du glissement et de la montee des dislocations dans un compose semiconducteur (3/5) : insb." Toulouse 3, 1987. http://www.theses.fr/1987TOU30070.
Повний текст джерелаMotsI, Glenda Tsholofelo. "In-situ scanning electron microscopy studies on the uniaxial tensile deformation mechanisms in Aluminium alloy 5083." 2014. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001710.
Повний текст джерелаAims to study tensile deformation mechanisms of aluminium alloy 5083 using in situ SEM techniques. The objectives to achieve this aim are: to investigate the effect of strain rate on mechanical properties ; investigating anisotropy mechanical properties at varying strain rates ; investigating microstructure anisotropy behaviour at varying strain rates and to investigate the influence of intermetallic particles during tensile deformation.
(11154630), George A. Warren. "Deformation Mechanisms in Unirradiated and Irradiated Iron Chromium Aluminum Identified by TEM in situ Tensile Testing." Thesis, 2021.
Знайти повний текст джерелаMo°scicki, Marcin [Verfasser]. "In situ diffraction analysis of single grain behaviour during tensile straining of polycrystals / von Marcin Mościki." 2010. http://d-nb.info/1007453885/34.
Повний текст джерелаPantano, Maria, Leonardo Pagnotta, Horacio Espinosa, and Sergio Rizzuti. "Design and application of a novel microelectromechanical system for in situ SEM/TEM displacement controlled tensile testing of nanostructures." Thesis, 2012. http://hdl.handle.net/10955/1187.
Повний текст джерелаSince the 1920s, different methodologies have been developed especially for mechanical characterization of material samples with characteristic length on the order of micro/nanometers. In the present manuscript, the main of such methodologies are presented and compared, in order to provide guidelines for mechanical characterization at the micro/nanoscale, and to identify the most versatile and effective among them. These are based on complete and miniaturized tensile testing stages, developed on proper microelectromechanical systems (MEMS). Because of their small size (they lie onto silicon wafers with area smaller than 1mm2 and thickness of only few micrometers), such testing devices are particularly suitable to handle micro/nanosized components, and can fit inside the tight chamber of scanning/ transmission electron microscopes (SEM/TEM), for real-time imaging of sample deformation. However, the effectiveness of the tests they allow to perform can be compromised by some disturbing phenomena, like onset of instability, as reported in a certain kind of tensile testing devices. In particular, these devices become unstable as soon as the sample under investigation shows stress relaxation, after some strain has been applied. Nevertheless, it is very important to be able to detect such singularities, since they may allow a deeper comprehen sion of materials’ behavior. In the present work, the above mentioned instability issue is overcome through the design of a novel device for in situ SEM/TEM tensile testing of nanostructures under true displacement control. Like other stages, also the one presented herein consists of two main components: an actuator and a sensor, which are separated by a small gap for positioning of the specimen. Actuation is performed by a thermal actuator, which pulls the end of the sample attached to it. The other end of the sample is instead connected to a displacement sensor, which moves from its equilibrium position, as a consequence of the force transmitted to it by the specimen. However, the main novelty of the present design is the introduction of a feedback control loop. In particular, a controller, implemented within a software routine, receives as input the sensor output, and computes the voltage to be applied to an electrostatic actuator, in order to generate a rebalance force of electrostatic nature, thus bringing the sensor back to equilibrium. In this way, the end ofand this boundary condition removes any potential source of instability. The MEMS sensing and actuating structures were designed by the means of both analytical and numerical approaches, in order to provide sufficiently high deformation (up to about 50% strain) and forces (up to 100μN) to break a variety of material samples. Fabrication was carried out by an external foundry on the basis of the masks drawings, reported in the present manuscript. In order to guarantee a correct functioning of the device, a proper experimental apparatus was developed. This allowed electrical connection of all of the actuating and sensing parts with external instrumentation, including current pre-amplifiers, power supplies, a lock-in amplifier, and a data acquisition card, which was used as interface between the controller and the MEMS device. The effectiveness of the present experimental apparatus was proven through an application on silver nanowires, with about 70 nm diameter and 3-4 μm gage length. The corresponding results, in terms of Young modulus, fracture and yield strength, showed good agreement with data already available in the literature, obtained for samples with comparable size. Also the device ability to detect singularities in the sample characteristic was demonstrated, as emerges from a load drop recorded after yielding of a nanowire. As a conclusion, the present experimental apparatus can be considered for future in situ SEM/TEM tensile tests on other material samples, as well as for electromechanical tests, since the specimen results to be electrically isolated from the remaining of the device. Thus, very interesting properties, like piezoresistivity and piezoelectricity, could be evaluated.
Università degli Studi della Calabria
Tahir, Muhammad. "Development of Novel Blends based on Rubber and in-situ Synthesized Polyurethane-urea." Doctoral thesis, 2017. https://tud.qucosa.de/id/qucosa%3A30765.
Повний текст джерела