We precisely measure the force-free swimming speed of a rotating helix in viscous and viscoelastic fluids. The fluids are highly viscous to replicate the low Reynolds number environment of microorganisms. The helix, a macroscopic scale model for the bacterial flagellar filament, is rigid and rotated at a constant rate while simultaneously translated along its axis. By adjusting the translation ...

An analysis of a novel indentation model has been implemented to obtain master curves describing the optimal experimental parameters necessary to achieve the highest possible accuracy in the determination of viscoelastic properties of soft materials. The indentation model is a rigid indenter driven by a compliant measurement system, such as an atomic force microscope or optical tweezers, into a...

The pounding tuned mass damper (PTMD) is a novel vibration control device that can be used for many different structures. The PTMD utilizes a viscoelastic delimiter to enhance its vibration control effectiveness and robustness though pounding between the tuned mass and the viscoelastic material. However, the viscoelastic material is subjected to repeated poundings during its service life, which...

Liquid crystal flexoelectric actuation uses an imposed electric field to create membrane bending and it is used by the Outer Hair Cells (OHC) located in the inner ear, whose role is to amplify sound through generation of mechanical power. Oscillations in the OHC membranes create periodic viscoelastic flows in the contacting fluid media. A key objective of this work on flexoelectric actuation re...

Ultrasound Contrast Agents (UCAs) composed ofgaseous microbubbles exhibit acoustic properties that differ fromthose surrounding tissue. In order to increase the contrast totissue ratio, it is necessary to propose methods that characterizeoptimally the ultrasonic properties of UCAs. The aim of thisstudy is to measure the viscoelastic properties of UCAs using adynamic acou...

Among the passive control techniques for vibration attenuation in composite structures demonstrated in the last decades, the use of viscoelastic material as a damping core in laminated beam like components is an interesting possibility but has not yet received sufficient attention so far. In order to gain an insight into this interest and develop more accurate and efficient viscoelastic-based v...

Title of Document: SURFACE CHARACTERIZATION OF VISCOELASTIC MATERIALS THROUGH SPECTRAL INTERMITTENT CONTACT ATOMIC FORCE MICROSCOPY Jeffrey Charles Williams, Master of Science, 2012 Directed By: Assistant Professor Santiago Solares Department of Mechanical Engineering The ability to recover material properties at the atomic scale has been the ongoing objective of the Atomic Force Microscope (AF...

AIMS We aim at developing a non-invasive method for grading and diagnosing urinary bladder outlet obstruction, based on noise recording with a perineal contact microphone during voiding. We found that the noise production during voiding depends amongst others on the viscoelastic properties of the urethral wall. To further test our method, we need a realistic biophysical model of the male urethr...

Cartilage material properties provide important insights into joint health, and cartilage material models are used in whole-joint finite element models. Although the biphasic model representing experimental creep indentation tests is commonly used to characterize cartilage, cartilage short-term response to loading is generally not characterized using the biphasic model. The purpose of this stud...

Using a strain-controlled rheometer, the dynamic viscoelastic properties of aqueous xanthan gum solutions with different concentrations were measured over a wide range of strain amplitudes and then the linear viscoelastic behavior in small amplitude oscillatory shear flow fields was investigated over a broad range of angular frequencies. In this article, both the strain amplitude and concentrat...