Recycling history

Figure 6.2 Optical images of the samples analysed in this work on the same row, samples subjected to a different number of recycling steps, but solidified under cooling rates of the same order of magnitude are reported on the same column, samples with the same recycling history but solidified under different cooling rates are reported. All the images are on the same magnification scale namely the longest side is about 400 pm. Reproduced with permission from F. De Santis and R. Pantani, The Scientific World Journal, 2013, Article ID 354093.

A comprehensive history of ferrous scrap recycling ia the United States beginning ia 1646 has beea pubUshed (3). Some selected eveats of iaterest iaclude the first opea-hearth steel produced (1868) the first commercial direct-arc electric furnace steel produced ia the United States (1906) the first large iaduction furnace iastaHed ia the United States (1914) the first basic oxygen steel produced ia the United States (1954) the rise of continuous casters and scrap-based minimills (1965) the first thin-slab continuous caster at a minimill (1989) U.S. exports and imports of ferrous scrap at record highs (1990) and the end of production of open-hearth steel (1991). 

Recycling, 529-574 closed-loop, 534 history of, 529-531 of urethane materials, 207-208 Reinforced polyamides, 139 Relative viscosity, 161 REPETE, 532 Repolymerization, 559-560 of EG and DMT, 561-562 Research... 

In November 1997, Ferrari (France) invited Solvay to help them to solve a problem of recycling PVC coated textile for light mobile structures, especially ones used for shortterm applications (advertising). The Vinyloop is aphysical recycling process making use of an organic solvent to separate the PVC compound from the other materials in a PVC composite. It is a closed loop process the solvent is completely recycled. Aspects outlined include history and a description of the process, precipitated PVC compound evaluation and financial data... 

The case histories presented in Section 21.6.4 to 21.6.6 demonstrate that fibers and titanium dioxide can be recovered from a whitewater by DAF under full flow pressurization mode or recycle pressurization mode with or without chemical addition.59... 

Unlike the age-abundance relation, the distribution function of stellar abundances of primary elements is independent of past rates of star formation as long as instantaneous recycling holds, and this makes it a potentially powerful clue to the evolutionary histories of stellar populations. 

Errors in the use of the instantaneous recycling approximation need to be considered, depending on the assumed history of star formation and mass ejection. After long times, e.g. 15 Gyr, low-mass stars eject relatively metal-poor material and modify the distribution in a similar way to what happens in some of the inflow models discussed below. However, it is still rather doubtful whether any Simple model can explain the abundance distribution function as well as satisfying other constraints. 

Wastewater Engineers, Inc. Case histories in wastewater recycling. Environ. Technol. 1999, 9 (7), 24-26. 

Regulatory facts ATSDR - minimal risk level (MRL) - inhalation 0.2 ig/m3 General facts long history of use, liquid silver evaporates at room temperature, bacteria convert to organic methyl mercury Environmental global environmental contaminant Recommendations avoid, recycle mercury-containing devices... 

This pattern began to change around the 1920s in response to three important developments. First, the United States became more urbanized. By 1920, for the first time in the nation s history, more people lived in urban areas (about 55 million) than in rural areas (about 50 million). The volume of solid wastes produced in cities and towns increased proportionally, and simple recycling systems of two decades earlier were more difficult to sustain. 

A general review on the art and methods of recycling has been given in the literature (25). In addition the history of plastics recycling is presented and the reasons for doing recycling are justified. 

The second example of process intensification at DSM is the urea process (5). The history of the urea process at DSM is rather long, as shown in Table 5. Urea is produced in a two-step process. The first step is the formation of carbamate from NH3 and C02. This reaction is exothermic. The second step is the decomposition of carbamate into urea and water. This second reaction is slightly endothermic. Both reactions are equilibrium reactions. The conversion to urea in equilibrium is about 60%. This means that substantial recycle flow is necessary to obtain sufficient overall conversion. In the reaction section the main unit operations are ... 

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