Experimental Measurement Techniques

A significant difficulty in characterizing and quantifying gas-liquid, liquid-solid, and gas-liquid-solid mixtures commonly found in bioreactor flows is that the systems are typically opaque (e.g., even an air-water system becomes opaque at fairly low volumetric gas fractions) this necessitates the use of specially designed invasive measurement probes or noninvasive techniques when determining internal flow and transport characteristics. Many of these probes or techniques were developed for a particular type of gas-liquid flow or bioreactor. This chapter first introduces experimental techniques to gauge bioreactor hydrodynamics and then summarizes gas-liquid mass transfer measurement techniques used in bioreactors. 

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In conjunction with its research activities, TPRC screens the world s literature and collects published information on a wide range of materials in the field of thermophysics. This information concerns data, theoretical estimation methods, and experimental measurement techniques. Technical papers come from journals, abstracting services, reports, doctoral dissertations, masters theses, and many other sources. The full evaluation and analysis of the collected raw data are needed before publications on recommended values can be prepared. Such effort is obviously time consuming and expensive and therefore this critical evaluation is currently performed at a rather modest funding level. The end result is that much of the available world literature is not being processed and distilled. 

Prasser, H.M. (2008), Novel experimental measuring techniques required to provide data for CFD validation, Nuclear Engineering and Design, 238(3) 744-770. 

With recent progress in nanofabrication, nanotechnology, and microfluidics [1-4], the field of nanofluidics is rapidly gaining importance. To meet the need of basic research in nanofluidics, e.g., measuring the profile of flow velocity and analyte in a nanochannel, experimental measuring techniques with nanoscale spatial resolution are required. Optical microscopic measuring techniques play a key role in microfluidics and nanofluidics and lab-on-a-chip. Unfortunately... 

A further aspect regarding the viscometric properties of liquid real systems which must be carefully considered when investigating this property—and in particular when one would expect reliable information on specific interactions between components—is represented by the choice of experimental measurement technique because it is possible to obtain two different quantities, such as kinematic viscosity (v/cSt, IcSt = Kk V) or dynamic viscosity (v/cP, IcP = lmPa s). These properties can be interconverted by the fundamental relation... 

A number of experimental measurement techniques are discussed, with a focus on noninvasive optical techniques such as particle image velocimetry and digital image analysis, as well as a number of academic numerical modeling tools such as discrete particle model and two-fluid model. Not only hydrodynamic aspects, such as the emergence of defluidized zones and solids circulation profile inversion, but also the effect on the bubble size distributions are discussed for wall-mounted membranes and horizontally immersed membranes. 

Specific Heat Capacity. Until recently the measurement of the specific heat capacity of pol3nmers, or of any substances for that matter, has not been a much sought-after research activity. This has been the case, not because heat capacity has not been recognized as an important and fimdamental thermal property, but because experimental measurement techniques, although perhaps deceptively simple in concept, require time-consuming and rigorous conditions. 

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