Characterization of mixing

To evaluate mixing it is necessary to have a quantitative measure. The variance from the mean is appropriate, but in a flowing system some fluid elements have a higher velocity than others. The concept in chemical engineering that is used to account for this is the mixing cup concentration. This is the concentration of fluid if the flow emptied into a cup that was well stirred. In mathematical terms, the mixing cup concentration is  

Note that the average velocity multiplied by the mixing cup concentration gives the total mole/mass flux through an area at position z. It is then natural to define the variance of the concentration from the mixing cup concentration  

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The special appeal of this approach is that it allows the heat of mixing to be estimated in terms of a single parameter assigned to each component. This considerably simplifies the characterization of mixing, since m components (with m 6 values) can be combined into m(m - l)/2 binary mixtures, so a considerable data reduction follows from tabulating 6 s instead of AH s. Table 8.2 is a list of CED and 6 values for several common solvents, as well as estimated 6 values for several common polymers. 

Table 12.6 Operating conditions for the characterization of mixing (the ratio between the flow rates being equal to 1).

Laboratory, where he worked with John Longo and Allan Jacobson on the synthesis and characterization of mixed metal oxides and their application in heterogeneous catalysis. He joined the chemistry faculty of Northwestern University in 1984 where he is now Professor of Chemistry and an active member of the Center for Catalysis and Surface Science and the Materials Research Science and Engineering Center. Kenneth Poeppelmeier has published over 250 research papers and supervised approximately 40 Ph.D. students in the area of inorganic and solid state chemistry. He is a Fellow of the American Association for the Advancement of Science (AAAS) and the Japan Society for the Promotion of Science (JSPS) and has been a Lecturer for the National Science Council of Taiwan (1991), Natural Science Foundation of China (1999) and Chemistry Week in China (2004), and more recently an Institut Universitaire de France Professor (2003). 

Baranski AS, Fawcett WR, Gatner K, Me Donald AC, MacDonald JR, Selen M (1983) Structural and compositional characterization of mixed CdS-CdSe films grown by cathodic electrodeposition. J Electrochem Soc 130 579-583... 

Ehreeld, W., Golbig, K., Hessel, V., Lowe, H., Richter, T., Characterization of mixing in micromixers by a test... 

Catalyst characterization - Characterization of mixed metal oxides was performed by atomic emission spectroscopy with inductively coupled plasma atomisation (ICP-AES) on a CE Instraments Sorptomatic 1990. NH3-TPD was nsed for the characterization of acid site distribntion. SZ (0.3 g) was heated up to 600°C using He (30 ml min ) to remove adsorbed components. Then, the sample was cooled at room temperatnre and satnrated for 2 h with 100 ml min of 8200 ppm NH3 in He as carrier gas. Snbseqnently, the system was flashed with He at a flowrate of 30 ml min for 2 h. The temperatnre was ramped np to 600°C at a rate of 10°C min. A TCD was used to measure the NH3 desorption profile. Textural properties were established from the N2 adsorption isotherm. Snrface area was calcnlated nsing the BET equation and the pore size was calcnlated nsing the BJH method. The resnlts given in Table 33.4 are in good agreement with varions literature data. 

Recently, the first structural characterization of mixed sulfur selenium dihalides, SeSX2 (X = Br, Cl), has been reported in mixtures of S2C12 and Se2X2 (X = Br, Cl).29,30 In addition, two-dimensional NMR exchange... 

Peakall, D.B., R.J. Norstrom, A.D. Rahimtula, and R.D. Butler. 1986. Characterization of mixed-function oxidase systems of the nestling herring gull and its implications for bioeffects monitoring. Environ. Toxicol. Chem. 5 379-385. 

Bebelis S, Kotsionopoulos N, Mai A, Rutenbeck D, and Tietz F. Electrochemical characterization of mixed conducting and composite SOFC cathodes. Solid State Ionics 2006 177 1843-1848. 

Mathew, T. Synthesis and characterization of mixed oxides containing cobalt, copper and iron and study of their catalytic activity , Ph. D Thesis, University of Pune, 2002. 

Qi LM, Ma JM, Cheng HM, Zhao ZG (1996) Synthesis and characterization of mixed CdS-ZnS nanoparticles in reverse micelles. CoUoids Snrf A 111 195-202... 

Brone D, Alexander A, Muzzio FJ. Quantitative characterization of mixing of dry powders in V-blenders. AIChE J 1998 44(2) 271-278. 

Sudah, O., D, Coffin-Beach, and F. J. Muzzio. Quantitative characterization of mixing of free-flowing granular materials in tote(bin)-blenders. Powder Technol. (in press), 2001. 

Fig. 29. Characterization of mixed monolayers left surface pressure/area isotherms of pure...

Al-Saden, A. A., A. T. Florence, T. K. Whatley, F. Puisieux, and C. Vautuion. 1982. Characterization of mixed nonionic surfactant micelles by photon correlation spectroscopy and viscb Hiylloid Interface Sci 86 51-56. 

Figure 1.188 Microscope images of the color formation due to a reactive characterization of mixing in the five mixing elements of the recycle-flow micro mixer (Re = 28 150 pm). Phenolphthalein and NaOH solutions were mixed [56] (by courtesy ofTransducer Research Foundation).

Fig, 6. Test reaction and characterization of mixing in the micromixer array... 

M.H. Chisholm, J.F. Coming, J.C. Huffman, The molybdenum-molybdenum triple bond. 14. Preparation and characterization of mixed alkoxy-thiolate compounds of formula Mo2(OR)2(SAr)4. Inorg. Chem. 23, 754-757 (1984)... 

Structural Characterization of Mixed-Stack Charge Transfer... 

In the reported experiments, transition metal ion concentrations were typically low, and electrolytes were added, and, hence, the results are not necessarily pertinent to industrial catalyst preparation. However, Raman spectroscopy was also applied for the characterization of mixed metal ion solutions with compositions of industrial relevance (Dieterle, 2001). Figure 7A, for example, shows the Raman spectra of solutions containing molybdenum, tungsten, and vanadium ions as a function of pH. At high pH values, for example, between 9 and 6, Raman bands were observed that evidence M0O42 and V10O286- species. Raman bands of hepta- and octa-molybdate, and decavanadate were observed upon acidification. At the pH... 

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