In-process techniques

It is of interest primarily for very uniform ultra-thin films and coatings (0.002-5 mils) in applications such as electrical resistors, thermistors, thermocouples, stator cores, connectors, fast-sensing probes, photo cells, memory units, dropwise steam condensers for recovery of sea water, pellicles for beam splitters in optical instruments, windows for nuclear radiation counters, panels for micrometeorite detection, dielectric supports for planar capacitors, encapsulation of reactive powders, and supports in x-ray and optical work. Any significant growth would depend upon a major breakthrough in process techniques and a consequent lowering in price. 

More recently, there have been in-process techniques developed. Focused Beam Reflectance Measurement (FBRN ) uses an immersion probe and is capable of in situ measurement of particle chord length. Obscuration measurement can also be used as an in line size measurement. Acoustic size measurement is also emerging as in-process technique that permits use in heavy slurries that are difficult to measure using optical techniques. 

Dust and solid residues treatment and re-use In-process techniques and operational measures may be considered for the minimisation of dust and residues. The collected dusts, slags and other solid residues may find an internal or external re-use. 

These ftictors have long hindered the development and commercial applications of these materials. It is only wifti die recent advances in processing techniques such as chemical-powder production, cold and hot isostatic pressing, chemical- and physical-vcqx>r deposition, and thermal spray that industry is now able to take better advantage of their remarkable prcqierties. 

The overall behavior of rodlike polymers discussed above can have important consequences in processing techniques which utilize concentrated solutions of rodlike polymers. 

Nanocrystallization via dewetting of materials has been observed in processing techniques, including ion implantation followed by thermal annealing, laser ablation, high-vacuum deposition, and molecular beam epitaxy In this section we focus on... 

Raman spectroscopy is relatively new as an in-process technique, yet several applications in routine analytics, quality and process control in various branches of industry (food, pharmaceutics, mineral... 

For several years, the French Atomic Energy Commission (CEA) has developed modelling tools for ultrasonic NDT configurations. Implemented within the CIVA software for multiple technique NDT data acquisition and processing [1,2], these models are not only devoted to laboratory uses but also dedicated to ultrasonic operators without special training in simulation techniques. This approach has led us to develop approximate models carrying out the compromise between as accurate as possible quantitative predictions and simplicity, speed and intensive use in an industrial context. 

Mean-centering, as is shown by experience, can be successfully employed in combination with another data pre-processing technique, namely scaling, which is discussed later. 

Catalyst recovery is a major operational problem because rhodium is a cosdy noble metal and every trace must be recovered for an economic process. Several methods have been patented (44—46). The catalyst is often reactivated by heating in the presence of an alcohol. In another technique, water is added to the homogeneous catalyst solution so that the rhodium compounds precipitate. Another way to separate rhodium involves a two-phase Hquid such as the immiscible mixture of octane or cyclohexane and aliphatic alcohols having 4—8 carbon atoms. In a typical instance, the carbonylation reactor is operated so the desired products and other low boiling materials are flash-distilled. The reacting mixture itself may be boiled, or a sidestream can be distilled, returning the heavy ends to the reactor. In either case, the heavier materials tend to accumulate. A part of these materials is separated, then concentrated to leave only the heaviest residues, and treated with the immiscible Hquid pair. The rhodium precipitates and is taken up in anhydride for recycling. 

Different resins have been developed for use in different reduction—ratio appHcation ranges (111,112). The powders suitable for high reduction—ratio appHcations, such as wire coatings, are not necessarily suitable for the medium reduction—ratio appHcations, such as tubings, or the low reduction—ratio appHcations, such as thread-sealant tapes or pipe liners. AppHcations and processing techniques are being used, which utilize the unique combination of properties offered by PTFE in fine powder form (113—115). 

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