In December 2003, the Physikalisch-Technische Bundesanstalt (PTB) started the development of an optical-based primary flow rate standard for application in natural gas under high pressures (up to 5.5 MPa). The concept underlying this technology will be presented in this paper. The technical approach is based on the application of a conventional laser Doppler velocimeter (LDV) as well as on a ne...

The present study deals with a laser Doppler dual-incident-beam velocimeter in reference-beam configuration developed at the Water Jet Lab of the Dipartimento di Meccanica of the Politecnico di Milano and especially designed for water jet applications. The applied experimental procedure makes it possible, once identified the contributors to the uncertainty of the measurand, to apply an analysis...

This study deals with the particle size measurement of nine aerosol metered dose inhalers. Calibration was made possible by the use of a laser particle velocimeter (aerodynamic Particle Sizer from TSI). The count median aerodynamic diameters (CMAD) show little variation, from 0.63 to 0.73 micron, with standard deviations (sigma g) between 1.2 and 1.8. Aerodynamic diameter aerosol diagram analys...

A precision ultrasonic velocimeter and a new differential method of calculation of specific concentration increments were employed to study the nonlinear acoustic properties of aqueous solutions of ten amino acids and six proteins. The greater precision of the velocity measurements allows much more dilute solutions to be treated, providing for a wider range of amino acids and proteins to be stu...

Field studies show that the internal screens in a gross pollutant trap (GPT) are often clogged with organic matter, due to infrequent cleaning. The hydrodynamic performance of a GPT with fully blocked screens was comprehensively investigated under a typical range of onsite operating conditions. Using an acoustic Doppler velocimeter (ADV), velocity profiles across three critical sections of the ...

The complications inherent in cannulation of the radial (group I) and dorsalis pedis (group II) arteries were studied in 46 patients. All the local and systemic variables which might be considered to contribute to damage of the artery were studied, from which it appeared that only the duration of cannulation, prothrombin time and partial thromboplastin time were significant in determining post-...

Synthetic pyrethroids are neurotoxic insecticides with a low mammalian toxicity. Prior investigations have found these agents to be neither cutaneous irritants nor sensitisers. Clinically demonstrable inflammation, as judged by erythema, oedema, or vesiculation, has not been apparent. Nevertheless, paraesthesia does result from cutaneous exposure. In this investigation technical grade flucythri...