Material recovery parameter

Generally, a variety of mechanical deformation processes cause the nonuniform deformation that results in the formation of residual stresses. This nonhomogeneous deformation in a material is produced by the material s parameters— largely its process parameters, such as the tool geometry and frictional characteristics. For example, the rolling of a strip can be accomplished by using squeeze rolls. In the rolling process, parameters with a small roll diameter and little reduction produce deformation penetration that is shallow and close to the surface, whereas the interior of the strip remains almost undeformed. After the removal of the deformation forces and a complete elastic recovery, this condition produces compressive residual stresses at the surface and tensile residual stresses in the core. 

Contrast in NMRI depends on both material-specific and operator-selected parameters. The material-specific parameters include the spin density and the relaxation times Tj and T2. The operator-selected parameters include the pulse sequence (inversion recovery, spin-echo, etc.) and the pulse delay and repetition times (timing parameters). For a given imaging system and pulse sequence, it is the delay and repetition times in conjunction with the intrinsic material parameters which dictate the appearance of the final image. If the correct pulse sequence is employed and the relaxation times of the two materials are known, it is possible to calculate the delay and/or repetition times that will produce the maximum diflerence in signal intensity between those materials. 

AH three parameters, the cut size, sharpness index, and apparent bypass, are used to evaluate a size separation device because these are assumed to be independent of the feed size distribution. Other measures, usually termed efficiencies, are also used to evaluate the separation achieved by a size separation device. Because these measures are dependent on the feed size distribution, they are only usefiil when making comparisons for similar feeds. AH measures reduce to either recovery efficiency, classification efficiency, or quantitative efficiency. Recovery efficiency is the ratio of the amount of material less than the cut size in the fine stream to the amount of material less than the cut size in the feed stream. Classification efficiency is defined as a corrected recovery efficiency, ie, the recovery efficiency minus the ratio of the amount of material greater than the cut size in the fine stream to the amount of material greater than the cut size in the feed stream. Quantitative efficiency is the ratio of the sum of the amount of material less than the cut size in the fine stream plus the amount of material greater than the cut size in the coarse stream, to the sum of the amount of material less than the cut size in the feed stream plus the amount of material greater than the cut size in the feed stream. Thus, if the feed stream analyzes 50% less than the cut size and the fine stream analyzes 95% less than the cut size and the fine stream flow rate is one-half the feed stream flow rate, then the recovery efficiency is 95%, the classification efficiency is 90%, and the quantitative efficiency is 95%. 

In this chapter, we will review the effects of shock-wave deform.ation on material response after the completion of the shock cycle. The techniques and design parameters necessary to implement successful shock-recovery experiments in metallic and brittle solids will be discussed. The influence of shock parameters, including peak pressure and pulse duration, loading-rate effects, and the Bauschinger effect (in some shock-loaded materials) on postshock structure/property material behavior will be detailed. 

Coran and Patel [33] selected a series of TPEs based on different rubbers and thermoplastics. Three types of rubbers EPDM, ethylene vinyl acetate (EVA), and nitrile (NBR) were selected and the plastics include PP, PS, styrene acrylonitrile (SAN), and PA. It was shown that the ultimate mechanical properties such as stress at break, elongation, and the elastic recovery of these dynamically cured blends increased with the similarity of the rubber and plastic in respect to the critical surface tension for wetting and with the crystallinity of the plastic phase. Critical chain length of the rubber molecule, crystallinity of the hard phase (plastic), and the surface energy are a few of the parameters used in the analysis. Better results are obtained with a crystalline plastic material when the entanglement molecular length of the... 

A ductile material can be stretched uniformly only when stable flow occurs. The stable flow of materials has been investigated by Hart who described the transition from the stable to unstable flow. The beginning of geometrical instability and localisation of strain is the limit of the stable flow. At temperatures above 0.5 T (at equilibrium between recovery and hardening) the strain rate sensitivity parameter "m" may be derived from the expression ... 

In order to judge performance capabilities that exist within the controlled variabilities, there must be a reference to measure performance against. As an example, the injection mold cavity pressure profile is a parameter that is easily influenced by variations in the materials. Related to this parameter are four groups of variables that when put together influences the profile (1) melt viscosity and fill rate, (2) boost time, (3) pack and hold pressures, and (4) recovery of plastica-tor. TTius material variations may be directly related to the cavity pressure variation. Details on EQUIPMENT/PROCESSING VARIABLE are in Chapter 8. 

The application of a selective pyrolysis process to the recovery of chemicals from waste PU foam is described. The reaction conditions are controlled so that target products can be collected directly from the waste stream in high yields. Molecular beam mass spectrometry is used in small-scale experiments to analyse the reaction products in real time, enabling the effects of process parameters such as temperature, catalysts and co-reagents to be quickly screened. Fixed bed and fluidised bed reactors are used to provide products for conventional chemical analysis to determine material balances and to test the concept under larger scale conditions. Results are presented for the recycling of PU foams from vehicle seats and refrigerators. 12 refs. 

Applications and limitations of the active interior gas collection/recovery system are similar to those of the active parameter gas control system. The active interior gas collection/recovery systems can be used at virtually any site where there is the capability to drill and excavate through landfilled material to the required depth. Limiting factors of the active interior gas collection/ recovery systems include the presence of free-standing leachate or impenetrable materials within the landfill. 

Verification of the proper choice of the enrichment method can be done through recovery studies under varying conditions of the most important parameters, such as amount and quality of the enrichment material, pH of the sample, as well as the amount and quality of analyte and matrix to be enriched. These parameters not only differ based on the chemical behaviour of the analyte, but are also strongly dependent on the matrix to be analysed. 

Quite often the most crucial parameter for SPE of compounds for which no enrichment techniques for environmental samples can be found in the literature is the selection of the proper SPE material. For example, during extraction of the two non-ionic surfactants, alkyl glucamides (AGs) and alkyl polyglucosides (APGs) from a spiked WWTP effluent (5 xgL-1) using RP-C18 cartridges, it was found that this material was unsuitable for quantitative enrichment (recovery <30%). Satisfactory results were obtained using PS-DVB material (Lichrolut EN) [45] (Table 3.1.2). 

However, to define conventional petroleum, heavy oil, and bitumen, the use of a single physical parameter such as API gravity or viscosity is not sufficient and is only a general indicator of the nature of the material. Other properties, such as the method of recovery, composition, and most of all, the properties of the bnlk deposit, must also be included in any definition of these materials. Only then will it be possible to classify petroleum and its derivatives (Speight, 1999). 

As for container material, polypropylene containers are as satisfactory as glass ones in compound stability and recovery. Since water is more harmful than oxygen to compound degradation and the hygroscopic nature of DMSO favors water uptake, humidity control is a key parameter to ensure compound storage stability. 

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