نتایج جستجو برای: viscoelastic moduli were increased and loss moduli were higher than storage modulus

تعداد نتایج: 17030426  

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه سمنان 1392

in the area of vocabulary teaching and learning although much research has been done, only some of it has led to effective techniques of vocabulary teaching and many language learners still have problem learning vocabulary. the urge behind this study was to investigate three methods of teaching words. the first one was teaching words in context based on a traditional method of teaching that is,...

Journal: :Investigative ophthalmology & visual science 2016
Ioannis M Aslanides Claudia Dessi Panagiotis Georgoudis Georgios Charalambidis Dimitris Vlassopoulos Athanassios G Coutsolelos George Kymionis Achyut Mukherjee Theofanis N Kitsopoulos

PURPOSE The effect of ultraviolet (UV)-riboflavin cross-linking (CXL) has been measured primarily using the strip extensometry technique. We propose a simple and reliable methodology for the assessment of CXL treatment by using an established rheologic protocol based on small amplitude oscillatory shear (SAOS) measurements. It provides information on the average cross-link density and the elast...

Journal: :Journal of the mechanical behavior of biomedical materials 2015
Jourdan Colter Alex Williams Patrick Moran Brittany Coats

Multiple rheological studies have characterized the dynamic material properties of adult vitreous, but no studies have investigated vitreous properties in the immature eye. In this study, premature, infant and adult ovine vitreous specimens were tested in shear to identify differences in dynamic moduli with age. Significant inertial artifact and rapid degradation of the vitreous ex vivo hindere...

Journal: :Physical review letters 1995
Mason Weitz

We present a novel experimental method to measure linear viscoelastic moduli of complex fluids using dynamic light scattering. A generalized Langevin equation is used to relate the mean square displacement of a probe particle to the storage and loss moduli of the bulk complex fluid. We confirm the experimental validity of this technique by comparing the light scattering results with mechanical ...

In this paper dynamic damping properties of a nominated flexible structural adhesive have been identified using an extended-direct modal based joint identification method. It has been revealed that damping characteristics of adhesive are correlated to both frequency and mode shape. Young’s and shear moduli increase with frequency but damping on the other hand, decrease. The results showed that ...

Journal: :NMR in biomedicine 2011
Kaspar-Josche Streitberger Edzard Wiener Jan Hoffmann Florian Baptist Freimann Dieter Klatt Jürgen Braun Kui Lin Joyce McLaughlin Christian Sprung Randolf Klingebiel Ingolf Sack

Nearly half a century after the first report of normal pressure hydrocephalus (NPH), the pathophysiological cause of the disease still remains unclear. Several theories about the cause and development of NPH emphasize disease-related alterations of the mechanical properties of the brain. MR elastography (MRE) uniquely allows the measurement of viscoelastic constants of the living brain without ...

2017
J. C. Earnshaw R. C. Mcgivern P. J. Winch

2014 Glycerol mono-oleate monolayers at the air-water interface have been investigated by quasielastic light scattering from thermally excited capillary waves over a wide range of wave numbers. Using a relatively novel data analysis procedure four surface viscoelastic properties were deduced ab initio from the light scattering data : surface elastic moduli and viscosities governing shear normal...

2017
Pavel Kuzhir Ana Gomez-Ramirez Modesto Lopez-Lopez Georges Bossis Andrey Zubarev P. Kuzhir A. Gómez-Ramírez M. T. López-López G. Bossis A. Yu. Zubarev

This paper reports the first study on the large amplitude oscillatory shear flow for magnetic fiber suspensions subject to a magnetic field perpendicular to the flow. The suspensions used in our experiments consisted of cobalt microfibers of the average length of 37 μm and diameter of 4.9 μm, dispersed in a silicon oil. Rheological measurements have been carried out at imposed stress using a co...

Journal: :journal of dentistry, tehran university of medical sciences 0
abbas monzavi associate professor, laser research center of dentistry, dentistry research institute, department of prosthodontics, tehran university of medical sciences, tehran, iran. hakimeh siadat associate professor, dental implant research center, dentistry research institute, department of prosthodontics, tehran university of medical sciences, tehran, iran. mohammad atai professor, iran polymer and petrochemical institute (ippi), tehran, iran. marzieh alikhasi associate professor, dental research center, dentistry research institute, department of prosthodontics, tehran university of medical sciences, tehran, iran. vahideh nazari resident of prosthodontics, tehran university of medical sciences, tehran, iran. sadigheh sheikhzadeh resident of orthodontics, tehran university of medical sciences, tehran, iran.

little is known about the interaction of tissue conditioners and modeling plastics. this study evaluates the influence of a variety of commercial tissue conditioners on alteration of viscoelastic properties of modeling plastics.in this in vitro study, the dynamic viscoelastic properties of four commercially available tissue conditioners (tc), visco-gel (vg), gc soft-liner (sl), fitt (ft), and c...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تبریز 1381

‏‎this study investigated the effect of prior knowledge on the listening comprehension performance of fl learners. twenty students, male and female, drawn from the two intact groups of the senior and junior english language and literature majors were chosen as the participants of this study . the two groups were then randomly assigned into the experimental and control group. the experimental gr...

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