Sorting methods

Ore reserves, marine, 17 685 Ore roasting, sulfur recovery from, 23 772 Ore sorting machine, 16 625 Ore sorting methods, 16 624-626 Oretic, 5 168... 

At the present time new deposits have been discovered which contain diamonds without luminescence under X-ray excitation. Sometimes the portion, which is unrecoverable in X-ray luminescent sorters, is big enough to warrant the development of a new sorting method. The luminescence spectra were investigated under excimer (193,222,248 and 308 nm), nitrogen (337 nm) and dye laser (340-360 nm) excitations (Fig. 8.2). 

There are several different approaches that are commonly used to determine particle size distributions in air. One of them, impaction, has been discussed earlier. Multistage impactors with different cut points are used extensively to obtain both mass and chemical composition data as a function of size for particles with diameters > 0.2 /xm. Others, including methods based on optical properties, electrical or aerodynamic mobility, and diffusion speeds, are described briefly in the following section. The condensation particle counter (CPC) is used as a detector in combination with some of these size-sorting methods. 

It is possible that the future may also see the use of digital calculators in qualitative spectrometric analyses. Various types of punched cards have been used as a method of recording spectral data on pure compounds. The purpose of these files is to facilitate the identification of spectral data on unknown substances. Their use in infrared analysis has been covered by Mecke and Schmid (M6), Keuntzel (K3), and Baker, Wright, and Opler (B2). The last named authors describe a file of 3150 spectra which was expected eventually to be expanded to include up to 10,000 spectra. Zemany (Zl) discussed the use of edge-notched cards in cataloging mass spectra and Matthews (M4) describes a similar application in connection with X-ray diffraction powder data. These two applications made use of only hand-sorting methods the files of Baker et al. were intended to be processed by machine. 

A variety of tools address the stoichiometry and molecular weight of compounds. The necessary condition that at least two metals be present for multiple metal bond formation is a simple sorting method for initial studies the molecular unit as determined by any type of molecular weight study must correspond to that of at least two metals per molecule. Conductivity measurements supply similar data for ions, and mass spectral data can indicate the presence of at least two metals per molecule. Analytical data with nonintegral ligand-to-metal ratios require that some multiple number of metal centers be present in order to formulate a stoichiometric compound. This array of techniques only eliminates the possibility of metal—metal bonds for mononuclear metal complexes, and further studies are always necessary to confirm the presence of an attractive metal-metal interaction. 

Fig. 1. Example of directed sorting method. (See color insert.)...

The directed sorting method will first be illustrated by the preparation of libraries of piperazine-2-carboxamide derivatives.18 The piperazine-2-carboxylic acid scaffold is a pharmacologically important19 center core... 

The directed sorting method has also been used to produce a large amount of compound (up to 100 mg).26 In the following example, the method was used to generate 100 mg of 3-aminobenzothiazepine derivatives. Each derivative was then acylated with 20 different carboxylic acids using the tetrafluorophenol resin (TFP-resin).27 Overall this allowed a large library of 16,000 discrete compounds to be produced. 

It is generally known that to obtain pure fractions from a mixture of different plastics is a more expensive process than separation of simple clean polymers, in plant. Therefore, it is anticipated that the separation of a municipal mixed plastic waste should be the most challenging. In such a fraction, traces of foods, labels, dirt (size mm), solvents (alcohols, petrol etc.), metals, low molecular weight products of different origins etc. could be found. Some of the sorting methods used are listed in Table 1. 

Herpin TF, Van Kirk KG, Salvino JM, Yu ST, Labaudiniere RF, Synthesis of a 10,000 member l,5-benzodiazepine-2-one library by the directed sorting method, J. Comb. Chem., 2 513-521, 2000. 

Waste plastics composition varies with collection area, sorting methods and time period, moreover several waste constituent polymer types occur in various waste categories. Nevertheless each customary plastic material will be discussed only in one of the three waste group included in this chapter. 

Copy method, the Cut method, the FillDown method or the Sort method. For example,... 

VBA methods usually take one or more arguments. The Sort method, for example, takes 10 arguments. The syntax of the Sort method is... 

A. Radbruch, B. Mechtold, A. Thiel, S. Miltenyi, and E. Pflueger, High-gradient magnetic sorting. Methods Cell Biol 42 387-403 (1994). 

Over the years, many mathematics-based sorting methods, called clustering antdysis, have been developed. For more details see Kusiak (1990) and Chang et al. (1998). 

Most collection schemes generate heterogeneous material streams, which must be efficiently sorted to provide generic material streams. Frequently-used sorting methods are ... 

Each of the described collection and sorting methods have inherent strengths and weaknesses. They will most likely have to be used in combination to achieve good sorting. It remains to be seen whether the economy and energy efficiency of such systems will be competitive compared to incineration or landfill. As will be seen, the efficiency of this first step of plastics recovery determines not only the way the material will be recycled but also the applications for the generated feedstock. 

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