PRELIMINARY CLEANING

Additional attention should be paid to the water hardness. Due to the presence of calcium, magnesium, and other alkali metals, hard water interferes with the effectiveness of detergents, particularly bicarbonates, and contributes to the formation of precipitates or scale on equipment. Besides diminishing the appearance of equipment, these precipitates serve as sites for accumulation of organic debris and microorganisms, making sanitation difficult if not impossible. Perhaps the least expensive method to alleviate this problem is through installation of a water softener. 

To prevent compromising the integrity of the protective oxide coating on stainless steel, only soft-bristle brushes should be used in cases where scrubbing is required. Once stainless steel surfaces are scratched, these rapidly become susceptible to oxidation and corrosion. As such, fiber or metal scratch pads or brushes should never be used for removal of tenacious deposits. 

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Silica [7631-86-9 (colloidal)-, 112945-52-5 (fumed)]. Purification of silica for high technology applications uses isopiestic vapour distillation from cone volatile acids and is absorbed in high purity water. The impurities remain behind. Preliminary cleaning to remove surface contaminants uses dip etching in HF or a mixture of HCl, H2O2 and deionised water [Phelan and Powell Analyst 109 1299 1984],... 

Preparation of basis metals for plating Preliminary cleaning of various basis metals follows the broad principles used for electrodeposited nickel. 

To better illustrate the purpose behind the cleaning steps, the conventional RCA cleaning process will first be examined in detail. It was developed for wafer cleaning in 1965, published in 1970 (Kern and Puotinen, 1970) and is still of importance. The following Table 6-1 shows the steps of the preliminary cleaning and the conventional RCA cleaning, as well as the purpose of each step. 

Comparison of the IMEC process with the RCA cleaning shows a drastic reduction in the number of necessary steps. The RCA with preliminary cleaning includes nine steps, this is... 

For glassware covered with a coat of heavy greasy material, preliminary cleaning should be done either with acetone or with a coned soln of NaOH in dil ale... 

For mycotoxin analyses radioimmunoassay (RIA), enzyme-linked immunosorbent assay (ELISAs) and affinity chromatography are the principal immunochemical methods in commercial application. Immunoaffinity columns or cartridges for specific mycotoxins are now being increasingly used in preliminary clean-up of extracts prior to final analysis by HPLC or GLC methods. 

Aside from softening, a smaller amount of oils and fats as detergents are also used in preliminary cleaning of the raw skins and hides to suspend lime particles, buffer the alkaline solution that removes the epidermis and hair, and suspend these materials when they come off to remove grease to tan certain types of leather and to control the penetration of dyes. 

Multilayer films were fabricated directly on one side of preliminary cleaned in a piranha solution quartz crystal resonators with gold working surface having the basic oscillation frequency of 5 MHz. The resonators were covered with a PEI/PSS layer if needed. The adsorption of PEI and PSS was carried out from 1 mg/mL polyelectrolyte solutions. Each adsorption step was followed by washing the resonator with the film in distilled water to remove an excess polyelectrolyte. 

Gravitational settling method is effective only for pollutant particle size larger than 50-100 microns. This method is suitable only for preliminary cleaning of gases. 

In experiments on the adhesion of a powder, HOPE modified by oil-soluble contact Cl containing salts of organic amines or sulfur acids with either carboxyl or hydroxyl groups has been used. The composition of HDPE - - Cl has been applied to a preliminary cleaned and degreased 100—pm-thick aluminum foil at a temperature of T = 155 5°C and a pressure of p = 7—10 MPa. The splices have then been subjected to thermal treatment in an oven at 200° C for one hour, which corresponded to the maximum strength of the adhesive joints. The strength has been estimated by delamination tests under a constant deformation rate. Not less than 20 samples were tested in each point to show 10-30% variation factor at a confidence interval of 0.95. 

The quartz plates were preliminary cleaned and hydrophilized using a standard technique ("piranha", RCA). Protamine sulfate/carboxymethylcellulose (PtS/CMC) films were fabricated by the layer-by-layer (LbL) method from 1.5 mg/mL solutions of PtS (Mw 5000) and CMC (Mw 250000) in distilled water at pH 7.0. The method is described in details elsewhere [8]. The films containing up to 20 (PtS/CMC) bilayers were used for testing of dye adsorption. 

Bulk Extraction of Anacardic Acids for NMR. Separate batches (2.5Kg each) of resistant and susceptible inflorescences were soaked in methylene chloride for one hour. The methylene chloride extracts were dried, filtered and evaporated as described above to leave crude resistant and susceptible exudates. A preliminary clean up of each was performed using column chromatography. Each crude extract was dissolved in hexane (15mL) and 5mL of that was applied to a silica gel chromatography column (18cm x 2cm) and eluted successively with (i) hexane (lOOmL), (ii) 4% diethyl ether, 1% acetic acid in... 

The purpose of preliminary cleaning of gases that arise from coal utilization is the removal of materials such as mechanically carried solid particles (either process products and/or dust) as well as liquid vapors (i.e., water, tars, and aromatics such as benzenes and/or naphthalenes) in some instances, preliminary cleaning might also include the removal of ammonia gas. 

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