Pock marks

Hydrocarbons are of a lower density than formation water. Thus, if no mechanism is in place to stop their upward migration they will eventually seep to the surface. On seabed surveys in some offshore areas we can detect crater like features ( pock marks ) which also bear witness to the escape of oil and gas to the surface. It is assumed that throughout the geologic past vast quantities of hydrocarbons have been lost in this manner from sedimentary basins. 

Orange Peel the pock-marked appearance, in particular of a sprayed film, resembling the skin of an orange due to the failure of the film to flow out to a level surface. (See also spray mottle.)... 

Mariner 9 tly-by of Mars revealed a surface remain of massive blocks of tumbled character cut by ridges and grahen-type troughs Huge volcanic peaks dominate a pock-marked landscape. Extensive channels characierislrc of concentrated erosive powers of torrential floods were also evident, as were braided stream systems emanating front what were resolved to be plateau-type elevations. 

Fig. 7 y-Radiation-induced grafting of acrylamide onto LDPE films, a Blank, b low grafting with beam damage giving rise to cracking, buckling and pock marks on the surface and c uniform multiphase formation with less beam damage... 

The identified characteristics of secondary hydrocarbon migration can be verified with e.g. the location and physico-chemical characteristics of known hydrocarbon accumulations (e.g. England and Mackenzie, 1989) direct and indirect observations of oil and gas seeps (direct visual observations indirect observations, such as hydrocarbon-charged sediments, pock marks, clay diapirs) and gas leakages indicated by seismic chimneys. 

Charcoals—the kind you draw with or cook with—are another type of poorly organized carbon molecules. Charcoals are produced from the burning of organic matter. If you look closely at a chunk of charcoal, you can see that it s extremely porous. All these pores, pock marks, and holes give charcoal a large surface area. Some charcoal, called activated charcoal, has as much as 1000 m of surface area per gram. This property makes activated charcoal useful in filtering water. Molecules, atoms, and ions responsible for unwanted odors and tastes in water are attracted to and held by the... 

What causes the progression of the seasons Phases of the moon The Aurora Borealis How much does the sun weigh What are the chances of life on our sister planets Absorbing introduction to astronomy, incorporating the latest discoveries and theories the solar wind, the surface temperature of Venus, the pock-marked face of Mars, quasars, and much more. Places you on the frontiers of one of the most vital sciences of our time. Revised (1966). Introduction by Donald H. Menzel, Harvard University. References. Index. 45 illustrations. i8gpp. hV x 8 4- Paperbound 1,50... 

Pock marks Air bubbles adhering to pipe in flotation tank Improper adjustment of spray rings that surround water tank Install wiper in tank Readjust spray rings... 

Pock mark n. An imperfection on the surface of a blow-molded article, an irregular indentation caused by inadequate contact of the blown parison with the mold surface. Contributory factors are insufficient blowing pressure, air entrapment, and condensation of moisture on the mold surface. 

Fig. 5.71 Semicrystalline thermoplastics, such as a polyacetal, shown in polarized light (A) do not appear spherulitic after the addition of calcium carbonate (B). llie surface of such a filled, molded part can exWbit a matte finish due to poor wetting of the particles with the pol)nner. SEM observation of the molded surface (C) shows pock marks which are particles in cavities not filled with pol)nner. EDS mapping (D) shows the particles contain calcium.

A good example of a cracked, beam damaged specimen is the surface of a POM molding, shown by SEI in Fig. 4.27. The molded surface has a production related scratch mark and several particulate pock marks (Fig. 4.27A). Seconds... 

Internal cooling with air or water is also effective but more complicated than the external method. Water requires a special system that vents out the steam produced during the cooling. Water drops can leave marks on the molten resin which are called pock marks and are considered quality defects. The most common technique is air cooling, in which air is forced into and out of the mold. In addition to cooling, air pressure coun-... 

Press curing of Thiokol compounds should be done in a press with cooling capabilities for best results. A minimum press temperature of 150°C is recommended for best physical properties for a time dictated by the iheometer curve at the curing temperature. At the end of the cure cycle the press should be cooled under pressure to approximately 40°C before opening the press to avoid pock marks and other surface defects. Typical cure times at 154°C for Thiokol FA is 40 min and for Thiokol ST is 30 min. 

Pock-marked molded parts may be caused by a mold design that does not allow the air to escape readily, too small and incorrectly shaped performs, bumping or porous performs. 

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