Process parameters effects

A.P. Reynolds and W. Tang, Alloy, Tool Geometry, and Process Parameter Effects on Friction Stir Welding Energies and Resultant ESW Joint Properties, Friction Stir Welding and Processing, K.V. Jata, M.W. Mahoney, R.S. Mishra, S.L. Semi-atin, and D.P. Eield, Ed., TMS, 2001, p15-23... 

M.J. Peel, A. Steuwer, and P.J. Withers, Dissimilar Friction Stir Welds in AA5083-AA6082, Part II Process Parameter— Effects on Microstructure, Metall. Mater. Trans. B, Vol. 37, July 2006, p 2195-2206... 

The optimal combination of the EMM process parameters and their combined effect on MRR and accuracy is found out based on the developed second-order mathematical models, i.e., Eqns (8.2) and (8.3) for correlating the various process parameters effects with MRR and machining accuracy. Optimum factor levels that will maximize the MRR and minimize the accuracy related responses, i.e., WOCs are calculated and are listed in Table 8.4 for single optimization along with its predicted responses. MRR... 

R.J. de Klerk et al., Continuous circuit coprecipitation of arsenic(V) with ferric iron by lime neutralization Process parameter effects on arsenic removal and precipitate quality, Hydrometallurgy, 111-112 (2012), 65-72. 

AH Advani, NN Thadhani, HA Grebe, R Heaps, C Coffin, T Kottke. Dynamic modelling of material and process parameter effects on self-propagating high-temperature synthesis of titanium carbide... 

The effect of mechanical treatment on floe behavior is illustrated in Figure 5. In one work (40), identical slurries were treated with varying doses of the same polymer. At each dosage, it can be assumed that the same type of floe formed at the same rate. However, the dosage response was completely different depending on which parameter of the flocculated slurry was measured. Thus the term optimal flocculation caimot be appHed to any flocculant—substrate combination if the soHd—Hquid separation process or process parameter is not specified. 

Many more suppHers and information about their product line can be obtained from compilations such as the Modem Plastics Pmyclopedia (1) and the Thomas Register of Mmerican Manufacturers (2). The choice of a release agent depends on the process conditions involved and the nature of the contacting substrates (3). Apart from the obvious ease of release, other important requirements are minimal buildup of residues on mold substrate, minimal effect on the molded article, adequate film-forming abiHty, compatibiHty with secondary operations and other processing parameters, health and safety requirements, and cost. 

Effects of Rate Conditions. It is essential for commercial a-quartz crystals to have usable perfection growth at a high rate and at pressure and temperature conditions that allow economical equipment design. The dependence of rate on the process parameters has been studied (8,14) and may be summarized as follows. Growth rate depends on crystallographic direction the (0001) is one of the fastest directions. Because AS is approximately linear with AT, the growth rate is linear with AT. Growth rate has an Arrhenius equation dependence on the temperature in the crystallization zone ... 

Monitoring by Electromechanical Instrumentation. According to basic engineering principles, no process can be conducted safely and effectively unless instantaneous information is available about its conditions. AH sterilizers are equipped with gauges, sensors (qv), and timers for the measurement of the various critical process parameters. More and more sterilizers are equipped with computerized control to eliminate the possibiUty of human error. However, electromechanical instmmentation is subject to random breakdowns or drifts from caUbrated settings and requires regular preventive maintenance procedures. 

Adiabatic flame temperatures agree with values measured by optical techniques, when the combustion is essentially complete and when losses are known to be relatively small. Calculated temperatures and gas compositions are thus extremely useful and essential for assessing the combustion process and predicting the effects of variations in process parameters (4). Advances in computational techniques have made flame temperature and equifibrium gas composition calculations, and the prediction of thermodynamic properties, routine for any fuel-oxidizer system for which the enthalpies and heats of formation are available or can be estimated. 

Measuring process parameters on full-scale plants is notoriously difficult, but is needea for control. Usually few of the important variables are accessible to measurement. Recycle of material makes it difficult to isolate the effects of changes to individual process units in the circuit. Newer plants have more instrumentation, including on-line viscosimeters [Kawatra and Eisele, International ]. Mineral Processing, 22, 251-259 (1988)], mineral composition by on-line X-ray fluorescence, belt feeder weighers, etc., but the information is always incomplete. Therefore it is helpful to have models to predict quantities that cannot be measured while measuring those that can. 

The assessor should also find out whether an effective testing program is in place to help ensure the serviceability of process measurement equipment. The successful toller should have an established calibration program to address the accuracy of critical measurement equipment. Safety critical process parameters should be monitored and critical process equipment should automatically interlock when monitoring instrumentation detects safety critical deviations. Interlocks should either facilitate a remedy to the critical deviation or bring the process to the zero energy state. These instruments and interlocking devices should be routinely tested to ensure operational reliability. 

In order to illustrate the critical process parameters of SMB process validation, we will consider the separation of the racemic drug as described in Process design. The study represents the effect of the influence of feed concentration, number of plates and retention factor on the second eluting enantiomer. The simulation of the process for different values of feed concentration is performed and the variations of the extract and raffinate purities are shown in Fig. 10.10. 

Although Eq. (13) has been reported to fit the data well for Cl = 3.5, and C2 = - 2.0, it provides no information on the phase separation process. In fact, there is little understanding about how the physical morphology and mechanical properties evolve with polymerization and time. The effect of various process parameters on the phase separation and morphology is obtained implicitly via final properties of the polymers. This is illustrated... 

Most plants can be cost-effectively monitored using a microprocessor-based system designed to use vibration, process parameters, visual inspection and limited infrared temperature monitoring. 

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. 

Minimizing the cycle time in filament wound composites can be critical to the economic success of the process. The process parameters that influence the cycle time are winding speed, molding temperature and polymer formulation. To optimize the process, a finite element analysis (FEA) was used to characterize the effect of each process parameter on the cycle time. The FEA simultaneously solved equations of mass and energy which were coupled through the temperature and conversion dependent reaction rate. The rate expression accounting for polymer cure rate was derived from a mechanistic kinetic model. 

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