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Ferroelastic domain switching behaviour in lead zirconate titanate under mechanical and electrical loadingImlao, Soodkhet Bond, Materials Science & Engineering, Faculty of Science, UNSW January 2008 (has links)
In this thesis, ferroelastic domain switching behaviour of lead zirconate titanate ceramics, as used in devices such as actuators, was studied. In particular, the effect of cyclic frequency and amplitude were assessed to develop a correlation between macrostructural changes and fatigue behaviour, both in the bulk and in crack-tip process zones. A variety of experimental methods were used. Raman scattering enabled the poling state of the ceramics can be determined. However, it could not distinguish between the different preferred orientations of in-plane c-domains. Conversely, neutron and X-ray diffraction technique can detect domain orientation distribution and the preferred direction of c-domains. In this study, neutron diffraction was used to probe domain switching behaviour in bulk samples while high spatial resolution X-rays were employed to analyse a switching zone near a crack tip. Under cyclic mechanical loading, domain switching and the accumulation of ferroelastic strain becomes saturated with increasing number of cycles. Moreover, time-dependent deformation was investigated. The results show that a domain forward-switching process occurs during creep deformation while a domain backward-switching process takes place during recovery. In addition, it was found that the frequency of applied stress affects the saturation of the ferroelastic strain while its magnitude has an influence on the level of strain accumulated. Under static mechanical loading, it was found that the size of the crack-tip zone where stress-induced domain switching occurs with increase in the stress intensity factor but the degree of domain switching around the crack tip changes only slightly. Under cyclic electrical loading, the results present a strong link between the frequency of the applied field, remnant polarisation, domain switching and the resultant crack growth. The results show that polarisation fatigue, the size of the switching zone, and the crack growth rate is greater at lower loading frequency. The quantitative analysis of the time dependent mechanism as well as the effect of loading frequency and amplitude on domain switching was achieved by applying viscoelastic models. Importantly, these models can be used to explain domain switching behaviour and domain wall movement under cyclic loading and link these processes to macroscopic deformation.
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Soil management in an established irrigated vineyard, on a hard red duplex soilWheaton, Ashley D. Unknown Date (has links) (PDF)
Hard red duplex soils (HRDS) cannot sustain economically productive vineyards without careful management. An experiment was conducted at Rosbercon Vineyard, Picola from 1995 to 1998 in a vineyard block of Chardonnay on Ramsey rootstock planted in 1972. The hypotheses tested were: a) transient waterlogging decreases root growth and grapevine performance, and b) hardening of soil decreases root growth and grapevine performance. (For complete summary open document)
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Referenzmodellierung nicht-professioneller Domänen Softwaretechnik, Nachhaltigkeit, KooperationNaumann, Stefan January 2006 (has links)
Zugl.: Hamburg, Univ., Diss., 2006
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Field-driven and spin-transfer-torque-driven domain-wall dynamics in permalloy micro-/nano-structuresYang, Shuqiang, January 1900 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.
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Referenzmodellierung nicht-professioneller Domänen Softwaretechnik, Nachhaltigkeit, KooperationNaumann, Stefan January 2006 (has links)
Zugl.: Hamburg, Univ., Diss., 2006
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Einfluss des zellulären J-Domänen-Proteins Jiv auf die Replikation von PestivirenMüller, Alexandra January 1900 (has links) (PDF)
Zugl.: Giessen, Univ., Diss., 2005
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Internet-Domains Aufbau - Namensfindung - BewertungsgrundlagenLenz, Björn January 2005 (has links)
Zugl.: Köln, Fachhochsch., Diplomarbeit, 2005
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Einfluss des zellulären J-Domänen-Proteins Jiv auf die Replikation von PestivirenMüller, Alexandra January 2005 (has links)
Univ., Diss., 2005--Giessen
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Evolutionäres Domain-Engineering zur Entwicklung von AutomatisierungssystemenJost, Pascal. January 2007 (has links)
Zugl.: Stuttgart, Univ., Diss., 2007. / Druckausg. bei Shaker, Aachen erschienen.
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Soil moisture determination by frequency and time domain techniquesAntle, Chad L. January 1997 (has links)
Thesis (M.S.)--Ohio University, March, 1997. / Title from PDF t.p.
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