Mass efficiency

For smaller particles, the theory indicates that efficiency decreases according to the dotted line of Figure 7. Experimental data (134) (sofld line of Eig. 7) for a cyclone of Eig. 9 dimensions show that equation 15 tends to overstate collection efficiency for moderately coarse particles and understate efficiency for the finer fraction. The concept of particle cut-size, defined as the size of particle collected with 50% mass efficiency, determined by equation 16 has been proposed (134). 

To solve this problem, modern pesticide formulations use a variety of additives (adjuvants) to improve the mass efficiency. Surfactants and polymeric rheology modifiers are used to reduce spray drift, surfactants are used to modify surface tension and reduce... 

The general expression for reaction mass efficiency (RME), derived in Appendix B, for any individual chemical reaction is given by... 

A Microsoft Excel (Version 5.0 or higher) spreadsheet template form has been developed which allows the calculation of the complete reaction mass efficiency (RME) according to equation (4.1) and raw material cost (RMC) for any chemical transformation. Lines are numbered and line instructions are embedded in the same manner as a personal income tax form. Green metrics are evaluated to determine the greermess of the experiment in a rigorous quantitative way and to determine the bottom line cost of carrying out the experiment. Formula entries are inserted in appropriate cells to facilitate computation. Any... 

Figure 4.3 Radial pentagon representation of reaction mass efficiency (RME) showing dependence on four independent parameters given in equation (4.1).

Scheme 4.2 shows various organic reaction types and Figure 4.5 shows their corresponding radial pentagons based on actual experimental data. When these diagrams are compared side by side it is possible to visualize at a glance which types of reactions are better atom economical and reaction mass efficient performers than others. In particular, it is possible to pick out which of the four factors in equation (4.1) is responsible for a low or high RME... 

In terms of kernel reaction mass efficiency, the golden threshold for a single step reaction... 

Figure 4.6 (a) Graph showing full domains of atom economy, reaction yield and region where reaction mass efficiency exceeds a threshold value of a for a reaction whose minimum atom economy is zero, (b) Probability that such a reaction can achieve a threshold RME of at least a. i a = 0.61 8, p(a) = 0.08 (8%) as indicated by dotted lines. 

Maximize overall kernel reaction mass efficiency (RME). 

Eissen, M., Hungerbuhler, K., Dirks, S., Metzger, J. (2003) Mass Efficiency As Metric for the Effectiveness of Catalysts. Green Chemistry, 5, G25-G27. 

Andraos, J. (2007) On the Use of Green Metrics in the Undergraduate Organic Chemistry Lecture and Laboratory to Assess the Mass Efficiency of Organic Reactions. Journal of Chemical Education, 84, 1004-1010. 

Yield and other mass-related metrics such as atom economy, reaction mass efficiency and mass intensity have been examined by Constable et al with regard to their significance concerning greenness and costs. The importance of using a (product) concentration term, which can be mass intensity or mass index, is additionally emphasized by Laird et al This is in compliance with Winterton, who in his twelve more green chemistry principles demands the establishment of full mass balances. 

Some specific metrics for mass have been found to be useful and are described elsewhere. In addition to reaction mass efficiency described elsewhere and in Chapter 4, a useful metrics is Mass Intensity, defined as ... 

Mass Intensity may also be expressed as a percentage by taking the inverse and multiplying by 100. This metric is also known as mass productivity or mass efficiency and provides an indication of how much of the input mass, expressed as a percentage, is integrated into a final, saleable product (how much of what we buy ultimately produces a profit). This is perhaps valuable for its shock value and ease of interpretation, especially for non-technical business people. 

Total Mass Efficiency of the 4 in Wet Wall Electroinertial Precipitator... 

For an example of reaction mass efficiency being used to compare four different processes please see Section 10.4.1. 

Several other metrics include effective mass yield, atom economy, mass intensity, mass productivity, and reaction mass efficiency, which are defined by Equations 3.2-3.6. 

The data clearly indicated that the use of route 4 for the synthesis of radafaxine had several advantages, for example, lower Mass Intensity and greater Mass Efficiency, in comparison to the DKR procedure, route 3. 

Route RME (%) Mass intensity (kg/kg) Mass efficiency (%) FLASC score" Solvent score" % Improvement compared to T ... 

Using data on the mass efficiency and energy requirements of the processes, an estimate of the potenhal impact on the environment was undertaken. Key areas of public concern are greenhouse gas emissions, generation of acid rain, and any impact/effect on ozone depletion. In all of the areas evaluated, in particular the key areas of public interest, route 4 has significant environmental benefits, with reductions in emissions of between 60 and 80%. 

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