Mass-average size

Use the moment equations for constant growth rate in a MSMPR crystallizer to calculate (a) the surface-volume mean size and (6) the mass average size, (c) Compare these values with the sizes where a maximum occurs in the corresponding distribution curves. 

Mpj(ti) denotes the crystal mass on the -th sieve at time tu and J is the total number of sieves, which is 9 in this study. This function evaluates a change in the area of the mass based size distribution in 1 residence time. W/ is a weighting factor defined by Equation (2), and is a function of size so as to give a maximum weight to the class of the mass average size, i.e. the weighting factor of the class of the mass average size is 1.0. 

The above equation expresses the ratio of the mass of crystals in the y-th sieve class to the mass of crystals in the mass average size class, where, n(L) is the population density function approximated with a straight line at the steady state (see Fi e 3). 

At room temperature, potassium cyanide has fee crystal stmeture (65). Average potassium cyanide crystals inherently have three to four times the mass or size of sodium cyanide crystals. 

Average Particle Size A powder has many average sizes hence it is essential that they be well specified. The median is the 50 percent size half the distribution is coarser and half finer. The mode is a high-density region if there is more than one peak in the frequency cui ve, the distribution is said to be multimodal. The mean is the center of gravity of the distribution. The center of gravity of a mass (volume) distribution is defined by. Xyw = X XdV/X dV where dV = X dN dV is the volume of dN particles of size X This is defined as the volume-moment mean diameter and differs from the mean for a number or surface distribution. 

Most studies on heat- and mass-transfer to or from bubbles in continuous media have primarily been limited to the transfer mechanism for a single moving bubble. Transfer to or from swarms of bubbles moving in an arbitrary fluid field is complex and has only been analyzed theoretically for certain simple cases. To achieve a useful analysis, the assumption is commonly made that the bubbles are of uniform size. This permits calculation of the total interfacial area of the dispersion, the contact time of the bubble, and the transfer coefficient based on the average size. However, it is well known that the bubble-size distribution is not uniform, and the assumption of uniformity may lead to error. Of particular importance is the effect of the coalescence and breakup of bubbles and the effect of these phenomena on the bubble-size distribution. In addition, the interaction between adjacent bubbles in the dispersion should be taken into account in the estimation of the transfer rates... 

The methods by which polymers are prepared result in a mixture of molecular sizes whose properties depend on the average size of the molecules present. In principle there are a number of ways in which such an average can be calculated. The most straightforward is the simple arithmetic mean, usually called the number average molar mass, M. This is defined by the expression... 

The mass of the eroded fragments can then be obtained from the mass balance. The solution breaks down as the average size (s) approaches the aggregate size (e). Following Ziff and McGrady (1985), particle size distribution is obtained as... 

In calculations the values of 8j = 82= 0.98 were used. The average size of the crystals ( rx 6.2pm) have been defined with the help of a photomicrography of the active mass. As concentration of electrolyte did not change during the reaction, then Ck= 1, C = 1. The change of solid reagents... 

This study presents catalytic properties of Pd and Pt for hydrogen adsorption. Metals were deposited by easy to perform procedure on powder materials. This method does not required use of hydrogen as reactant gas and can be easy scale-up. Presence of metal particles was verified by SEM experiment. Average size of noble metals was approximately 1pm. From experiment conditions amount of catalyst was found and it was revealed that mass of metal (Pt or Pd) do not exceed l %wt. 

Usually, this also results in a smaller mass based average size (L50m) (1). 

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