A portable and affordable extensional rheometer for field testing

Extensional shear testing is often needed to characterise the behaviour of complex fluids found in industry and nature. Traditional extensional rheometers are typically expensive, fragile and heavy and are only suited to making measurements in a laboratory environment. For some applications, it is necessary to make in situ rheological measurements where, for example, fluid properties change rapidly over time or where laboratory facilities are unavailable. This paper reports the development and validation of an inexpensive, lightweight and robust 'open source' extensional rheometer, Seymour II. Validation was carried out experimentally and computationally. Measurements on a Newtonian fluid (492 mPa s Brookfield silicone oil) yielded results of 510  ±  51 mPa s; these are comfortably within the range of  ±10% which other authors have quoted for extensional techniques using laboratory rheometers. Comparison of the observed filament thinning dynamics to those obtained using computational fluid dynamics (CFD) gave good qualitative agreement. Use of Seymour II at the University of Cambridge Botanic Gardens revealed that the mucilage of the 'crane flower', $\textit{Strelitzia reginae}$, was a viscoelastic fluid whose extensional response could be described by a two-mode Giesekus equation. Engineering drawings and image analysis code for Seymour II are available for download at the project website, www.seymourII.org/.Support for a summer internship for NP from ENSTA, a PhD studentship for MPB from Sandvik Hyperion and Ceratizit, and a PhD studentship for OMM from Chemours

Lab on a stick: multi-analyte cellular assays in a microfluidic dipstick

A new microfluidic concept for multi-analyte testing in a dipstick format is presented, termed “Lab-on-a-Stick”, that combines the simplicity of dipstick tests with the high performance of microfluidic devices. Lab-on-a-Stick tests are ideally suited to analysis of particulate samples such as mammalian or bacterial cells, and capable of performing multiple different parallel microfluidic assays when dipped into a single sample with results recorded optically. The utility of this new diagnostics format was demonstrated by performing three types of multiplex cellular assays that are challenging to perform in conventional dipsticks: 1) instantaneous ABO blood typing; 2) microbial identification; and 3) antibiotic minimum inhibitory (MIC) concentration measurement. A pressure balance model closely predicted the superficial flow velocities in individual capillaries, that were overestimated by up to one order of magnitude by the Lucas-Washburn equation conventionally used for wicking in cylindrical pores. Lab-on-a-stick provides a cost-effective, simple, portable and flexible multiplex platform for a range of assays, and will deliver a new generation of advanced yet affordable point-of-care tests for global diagnostics

The European influence on workers' compensation reform in the United States

Workers' compensation law in the United States is derived from European models of social insurance introduced in Germany and in England. These two concepts of workers' compensation are found today in the federal and state workers' compensation programs in the United States. All reform proposals in the United States are influenced by the European experience with workers' compensation. In 2006, a reform proposal termed the Public Health Model was made that would abolish the workers' compensation system, and in its place adopt a national disability insurance system for all injuries and illnesses. In the public health model, health and safety professionals would work primarily in public health agencies. The public health model eliminates the physician from any role other than that of privately consulting with the patient and offering advice solely to the patient. The Public Health Model is strongly influenced by the European success with physician consultation with industry and labor

Comparative bioavailability: Eight commercial prednisone tablets

Two four-treatment crossover bioavailability studies were performed in panels of 12 adult male volunteers with eight different commercial prednisone tablets. Plasma samples from the first study were assayed by radioimmunoassay for both prednisone and prednisolone. Plasma samples from the second study were assayed for prednisolone only. Statistical analyses of the data showed significant differences in the rate of appearance of prednisolone in plasma, but not in the amount convened to prednisolone. Some observations are made on the relationships between prednisone and prednisolone concentrations in plasma following oral administration of prednisone .Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45064/1/10928_2005_Article_BF01086151.pd

Fluid Dynamic Gauging for Studying Early Stages of Swelling of Fouling Deposits

A new variant of the fluid dynamic gauging technique for determining the thickness of soft fouling layers in situ and in real time is reported. The sideways fluid dynamic gauging (SiDG) device allows measurements to be made shortly after a deposit layer contacts a solution, allowing processes such as swelling to be characterized accurately. Two applications of the device are reported: (i) in cleaning, monitoring the change of thickness of a complex food soil when it is contacted with aqueous solutions at different temperatures, pH and surfactant content, and (ii) in fouling, in determining the thickness, thermal conductivity and strength of deposits generated from whey protein solutions on heated stainless steel substrates. The evolution of fouling resistance for the whey protein deposits indicates that significant aging takes place during the fouling test, which is confirmed by changes in the thermal properties and strength of the deposit layer as measured by the SiDG device