Visible defects

The system uses a helium-neon laser to scan a wafer surface. Light scattered by defects is collected and amplified, and the resulting photomultiplier signals reveal the location and nature of the defect. Particles as small as 0.3 micron can be detected. 

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If either dry powders or inverse emulsions are not properly mixed with water, large lumps of polymer form that do not dissolve. This not only wastes material, but can also cause downstream problems. This is especially tme for paper where visible defects may be formed. Specialized equipment for dissolving both dry polymers and inverse emulsions on a continuous basis is available (22,23). Some care must be taken with regard to water quaUty when dissolving polyacrylamides. Anionic polymers can degrade rapidly in the presence of ferrous ion sometimes present in well water (24). Some cationic polymers can lose charge by hydrolysis at high pH (25). 

Transmission electron microscopy (T.E.M.) observations performed on our samples revealed not only the presence of the usual twin boundaries as the major visible defect but also, a set of columnar-like defects. In addition, the sample certainly contains also point defects, in particular oxygen vacancies. 

A difficult problem that prevented the use of nanofiltration in organic solvents for a long time was the limited solvent stability of polymeric nanofiltration membranes, and the lack of ceramic nanofiltration membranes. For polymeric membranes, different problems occurred zero flux due to membrane collapse [54], infinite nonselective flux due to membrane swelling [54], membrane deterioration [55], poor separation quality [ 5 6], etc. I n an early study of four membranes thought to be solvent stable (N30F, NF-PES-10, MPF 44 and MPF 50), it was observed that three of these showed visible defects after ten days exposure to one or more organic solvents, and the characteristics of all four membranes changed notably after exposure to the solvents [15]. This implies that these membranes should be denoted as semi-solvent-stable instead of solvent stable. 

Of course, not all bad food is a different colonr from good food. It has been found that certain non-visible defects (bacteria for example) fluoresce when irradiated with ultraviolet light (350 mn), and this property may be used as a basis for sorting. This technique was originally developed for removing stinkers from green Arabica coffee beans, but has found applications in sorting peanuts, almonds and cranberries. However, the fluorescence effects can be short lived and may also depend on the circumstances and time elapsed since the product was harvested. 

II Level, smooth, but with visible defects (stroke ... 

III Smooth, with visible defects substrate roughness ... 

Scaffolds and components must be inspected as required for the type of scaffold for visible defects by a competent person. 

Ladders must be periodically inspected by a competent person for visible defects and after any occurrence affecting their safe use. 

Before each work shift, and after any incident which could affect a scaffold s structural integrity, your company competent person must inspect all scaffolds and scaffold components for visible defects. According to OSHA this should adequately protect employees working on scaffolds and ensure that defects are detected before an accident happens. 

Each final container should be checked for visible defects (cracks, presence of visible particles, etc.). Products in which particles are detected should be discarded. 

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