A calibrated physical flow standard for medical perfusion imaging

In the medical sector, various imaging methodologies or modalities (e.g. MRI, PET, CT) are used to assess the health of various parts of the bodies of patients. One such investigation is the blood flow or perfusion of the heart muscle, expressed as the (blood) flow rate normalized by the mass of the volume of interest. Currently there is no...

Pixel-wise assessment of cardiovascular magnetic resonance first-pass perfusion using a cardiac phantom mimicking transmural myocardial perfusion gradients

Purpose: Cardiovascular magnetic resonance first-pass perfusion for the pixel-wise detection of coronary artery disease is rapidly becoming the clinical standard, yet no widely available method exists for its assessment and validation. This study introduces a novel phantom capable of generating spatially dependent flow values to enable...

Extrusion instability in an aramid fibre spinning process

The efficiency of polymer extrusion processes can be severely limited by the occurrence of viscoelastic extrusion instabilities. In a para-aramid fibre spinning process, for example, a ?m-scale extrusion instability is responsible for the waste of tons of polymer per year. At present, a considerable amount of research literature is available on...

An implicit rheological model for numerical simulation of generalized Newtonian fluids

Fitting an explicit curve over some discrete data extracted from a rheometer is the usual way of writing a rheological model for generalized Newtonian fluids. These explicit models may not match totally with the extracted data and may ignore some features of the rheological behavior of the fluids. In this paper, a cubicspline curve fitting is...

Hele-Shaw rheometry

In this paper, we describe a novel approach to determine the flow behavior index of a power-law fluid by means of a microfluidic device. The concept of this method is based on a mathematical analysis by Aronsson and Janfalk [Eur. J. Appl. Math. 3, 343–366 (1992)] of Hele-Shaw flow of power-law liquids. We implement this approach by driving a non...

Application of digital holography to filament size analysis

The potential of in-line digital holography to locate and measure the size and position of filaments, i.e. thin wire-like objects, distributed throughout a thick volume has been investigated. In this paper two approaches are introduced to study filaments of varying diameter. (1) It is shown analytically and experimentally that for a gradual...