1 Mechanical cleaning process

In the factory processes the sticklac is first passed through crushing rollers and sieved. The lac passes through the sieve but retains the bulk of the woody matter. The sieved lac is then washed by a stream of water and dried by a current of hot air. A second mechanical cleaning process removes small sticks which have not been removed in the earlier roller process. The product, seedlac, now contains 3-8% of impurities. 

The first water con tioning stage is almost invariably a mechanical cleaning stage it is absolutely necessary for all surface waters from rivers and lakes but is not needed for many well waters. Mechanical cleaning processes include ... 

The cleaning process proceeds by one of three primary mechanisms solubilization, emulsification, and roll-up [229]. In solubilization the oily phase partitions into surfactant micelles that desorb from the solid surface and diffuse into the bulk. As mentioned above, there is a body of theoretical work on solubilization [146, 147] and numerous experimental studies by a variety of spectroscopic techniques [143-145,230]. Emulsification involves the formation and removal of an emulsion at the oil-water interface the removal step may involve hydrodynamic as well as surface chemical forces. Emulsion formation is covered in Chapter XIV. In roll-up the surfactant reduces the contact angle of the liquid soil or the surface free energy of a solid particle aiding its detachment and subsequent removal by hydrodynamic forces. Adam and Stevenson s beautiful photographs illustrate roll-up of lanoline on wood fibers [231]. In order to achieve roll-up, one requires the surface free energies for soil detachment illustrated in Fig. XIII-14 to obey... 

Process-side cleaning. Either chemical or mechanical cleaning on the inside of the tubes can readily be accomplished. 

NOTE The view that deposition is an indicator of more widespread problems is also common to cooling water systems. As a result of the complex nature of deposits, their removal by acid or mechanical cleaning of boiler or cooling systems is not always as simple a process as may be portrayed. 

Zhang, R, Busnaina, A. A., Reng, J., and Rury, M. A., Particle Adhesion Force in CMP and Subsequent Cleaning Processes," Proceedings, 4th International Chemical-Mechanical Planarization for ULSI Multilevel Interconnection Conference, Santa Clara, CA, Reb. 11-12,1999, pp. 61-64. 

In general, the cleanup of oiled shorelines has been by mechanical, labor-intensive means. The use of surfactants to deterge and lift the oil from the surface results in more complete and rapid cleaning. Not only is the cleaning process more efficient, but it can also be less environmentally damaging because potentially less human intrusion and stress on the biologic community occurs and because the chemicals can make the washing more effective at a lower temperature. 

Introducing mechanical cleaning of vessels (e.g. wall wipers) and pipes (e.g. pipeline pigging) that process viscous materials and require periodic cleaning with water. 

Two hundred g of cotton was randomly taken from each of the six bulk samples to measure trash content. Each was weighed to two decimal places then mechanically cleaned in a Shirley analyzer ( ). After completing the first processing stage in the analyzer, the cleaned lint was recleaned seven additional times to completely remove visible trash. The trash box residue was recovered and entrained lint removed from it with the aid of forceps, hand cards, and sonic sieves. The remaining nonlint trash was weighed and its content in cotton computed in percentage units. 

B. Withers, E. Zhoa, R. Jairath, A Wide Margin CMP and Clean Process for Shallow Trench Isolation Applications, 1998 Proceedings of the Third International Chemical-Mechanical Planarization for VLSI Multilevel Interconnection Conference (CMP-MIC), Santa Clara, CA, pp. 319-327, Feb. 19-20,1998. 

We arbitrarily considered a maximum acceptable material removal during the cleaning process of 5 nm, which corresponds for an industrial 10-min process time to a 0.5 nm/min etching rate. Different oxidant-free mixtures able to remove particles by underetching mechanisms and covering the whole pH range were adjusted to remove—in 10 min — 5nm of PECD... 

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