Process Phenomena

Bruno G, Capezuttuto P and Losurdo M 1995 On the use of the piasma in iii-V semiconductor processing Phenomena In Ionized Gases (ICPIG Hoboken, NJ, 1995 (AiP Conference Proceedings voi 22) ed K FI Becker, W E Carr and E E Kunhardt (Woodbury, NY American Institute of Physics) pp 146-55... 

It is particularly important to study process phenomena under dynamic (rather than static) conditions. Most current analytical techniques are designed to determine the initial and final states of a material or process. Instmments must be designed for the analysis of materials processing in real time, so that the cmcial chemical reactions in materials synthesis and processing can be monitored as they occur. Recent advances in nuclear magnetic resonance and laser probes indicate valuable lines of development for new techniques and comparable instmmentation for the study of interfaces, complex hquids, microstmctures, and hierarchical assemblies of materials. Instmmentation needs for the study of microstmctured materials are discussed in Chapter 9. 

At sufficiently low strain, most polymer materials exhibit a linear viscoelastic response and, once the appropriate strain amplitude has been determined through a preliminary strain sweep test, valid frequency sweep tests can be performed. Filled mbber compounds however hardly exhibit a linear viscoelastic response when submitted to harmonic strains and the current practice consists in testing such materials at the lowest permitted strain for satisfactory reproducibility an approach that obviously provides apparent material properties, at best. From a fundamental point of view, for instance in terms of material sciences, such measurements have a limited meaning because theoretical relationships that relate material structure to properties have so far been established only in the linear viscoelastic domain. Nevertheless, experience proves that apparent test results can be well reproducible and related to a number of other viscoelastic effects, including certain processing phenomena. 

Ideally, a mathematical model would link yields and/or product properties with process variables in terms of fundamental process phenomena only. All model parameters would be taken from existing theories and there would be no need for adjusting parameters. Such models would be the most powerful at extrapolating results from small scale to a full process scale. The models with which we deal in practice do never reflect all the microscopic details of all phenomena composing the process. Therefore, experimental correlations for model parameters are used and/or parameters are evaluated by fitting the calculated process performance to that observed. 

Of course, whilst the aim of the modelling exercise is always to obtain as realistic a description of the process phenomena as possible, additional realism often involves additional numerical complexity and will demand additional data, which may be difficult or impossible to obtain. A marginal additional degree of realism can thus become rapidly outweighed by the large amount of extra time and effort needed. 

A Readers Advisory to the Best Books on the History of Science. Written by 200 International Scholars, the 600 Comparative Essays Begin with a Bibliography of Important Works, Followed by Reviews of Those Sources in the Body of the Entry. Important Concepts and Processes, Phenomena, and Scientists As Well As Scientific Developments in Different Countries Are Covered... 

As reviewed in Section 3.1.2.3, reaction calorimeters can be used to better understand and characterize scale-related process phenomena, such as mixing and heat transfer. A heat flow calorimeter, the Mettler RCle, is shown in Figure 1. A schematic of a similar calorimeter system is shown in Figure 2 [16]. A heat flow calorimeter can be used to estimate ... 

The identification of the elementary steps according to which the evolution of the investigated process (phenomena) is held. 

The statistical modelling of a process presents the main advantage of requiring nothing but the inputs and outputs of the process (the internal process phenomena are then considered as hidden in a black box). We give some of the important properties of a statistical model here below ... 

Keywords Methodology, Conceptual process synthesis. Process intensification. Process phenomena, Microstructured devices... 

Table 2. General principles for process phenomena manipulation.

Combine several process phenomena Combine reaction and distillation into a reactive distillation... 

The applications of TGA are extensive and diverse and include oxy-salt decompositions, natural and synthetic polymer characterization, metal oxidation and corrosion analysis, compositional analysis of coals, polymers, and rubbers, study of glass materials, foodstuffs, catalytic materials, biological materials, and a wide range of chemical processing phenomena. It has been used very successfully to study the kinetics of chemical processes however, there is much controversy surrounding this application, particularly in terms of relating TGA data to reaction kinetics models. 

Agglomeration Processes - Phenomena, Technologies, Equipment W. Pietsch... 

---