Cave-ins

In the above situation, the walls cave in from the sides, cutting off the void and presenting a new surface to the incoming gas. This sequence is illustrated in Figure 32. The size of the initial bubble resulting from a detached void is typically on the order of about half the penetration depth of the gas jet. Bubbles or gas voids rise in a fluidized bed by being displaced with an inflow of solids from their perimeters. 

Several construction buildings collapsed from the explosion (Figure 2.13). The facade of the factory partially collapsed, the brick wall was partially caved in, and a large number of windows in this wall were shattered. The glass roof of the factory... 

Tien, J. C. (1998). Longwall Caving in Thick Seams . Coal Age, April, pp. 52-54. 

This is set deeply enough to protect the borehole from caving-in in loose formations frequently encountered at shallow depths, and protects the freshwater sands from contamination while subsequently drilling a deeper hole. In case the conductor string has not been set, the surface casing is fitted with casing head and BOP. 

These cave drawings, found in Chauvet Cave in France, have been authenticated by C-14 dating to 30,000-28,000 B.c. It is the oldest known artwork in the world. 

A current 1.00-g sample of carbon shows 921 disintegrations per hour. If 1.00 g of charcoal from an archaeological dig in a limestone cave in Slovenia shows 5.50 X 103 disintegrations in 24.0 h, what is the age of the charcoal sample ... 

Grun, R., Beaumont, P.B. and Stringer, C. 1990 ESR dating evidence for early modem humans at Border cave in South Africa. Nature 344 537-539. 

Limestone caverns are among nature s most spectacular displays. These caves occur in many parts of the world. Examples are Carlsbad Caverns In New Mexico, Jeita Caves in Lebanon, the Blue Grotto in Italy, and the Jenolan Caves In Australia. Wherever they occur, the chemistry of their formation involves the aqueous equilibria of limestone, which Is calcium carbonate. Three such equilibria, linked to one another by Le Chatelier s principle, play essential roles In cave dynamics. 

Smith PE, Farquhar RM Hancock RG (1991) Direct radiometric age determination of carbonate diagenesis using U-Pb in secondary calcite. Earth Planet Sci Lett 105 474-491 Spalding RF, Mathews TD (1972) Submerged stalagmites from caves in the Bahamas Indicators of low sea level stand. Quat Res 2 470-472... 

Another technique that has been used for dating obsidians, albeit only those that were heated in the past, is the fission track technique (see Textbox 26) (Fleisher et al. 1975). Fission track dating was used, for example, to date the time when an obsidian knifeblade found at a cave in Elmenteita, in Kenya, was heated (see Fig. 24). Since the shape of the blade was distorted, it was deduced that the blade had been heated to a temperature sufficiently high to partially melt it. 

Kaplan L, MacNeish RS (1960) Prehistoric bean remains from caves in the Ocampo region of Tamaulipas, Mexico, vol 19. Botanic Museum Leaflet, Harvard University, Harvard University Press, Cambridge, pp 33-56... 

Renfrew, C. and Aspinall, A. (1990). Aegean obsidian and Franchthi Cave. In Les Industries Lithiques Taillees de Franchthi (Argolide, Grece). Tome II Les Industries de Mesolithique et du Neolithique Initial, Fasicule 5, ed. Perles, C., Indiana University Press, Bloomington, pp. 258-270. 

December Smith Wesson enters into a legal setdement with the city of Boston. It resolves some of the issues in the earlier failed agreement, and is restricted only to Smith Wesson s products. However, a number of gun advocacy groups organize a boycott of Smith Wesson to protest what they view as caving in to antigun forces. 

Volume 1 of the American Journal of Science contains a first-hand description, by Dr. Samuel Brown, of the niter caves of Kentucky, which have been known since the beginning of the nmeteenth century (46), R. N. Maxson described these caves in the Journal of Chemical Education for November, 1932 ( 47). 

Prior to Abbott s work, several individuals considered analogies between 2-D and 3-D worlds. For example, psychologist and physiologist Gustave Fech-ner wrote Space Has Four Dimensions in which a 2-D creature is a shadow man projected to a vertical screen by an opaque projector. The creature could interact with other shadows, but, based on its limited experience, could not conceive of a direction perpendicular to its screen. The idea of 2-D creatures dates back to Plato s Allegory of the Cave, in the seventh book of The Republic, where shadows are representations of objects viewed by 3-D observers constrained to watch the lower-dimensional views. Unlike Fechner, Plato does not suggest that the shadows have the capability of interacting with one another. 

The ESR dating was first recognized by the Anthropology Association of Greece at Petralona cave in 1976 and then at French CNRS Congress at Tautavel cave in 1981. The Specialist Seminar (SS) on TL Dating included ESR from its 3rd symposium as listed below for references. 

I entered a cave in the deep mountains where it seemed that I was to meet Steve Foote. Steve was busy (giving a talk), and I supposed that I could save time by making a shortcut through the cave. I plunged ahead, but by now I was afoot and/or even flying, although it still felt like an extension of my bike ride. I remember thinking it shouldn t take me more than a day to get to Colorado (or was it back to Boston ). 

That carbonate of soda (nitrum) occurred in the form of stalactites in mountain caves in Goslar is doubtless an error, and the inhabitants were probably more nearly correct than Albertus who judged by sight and touch (visu et tactu), though both may have been at fault. The term sal-nitri or sal-nitrum meaning our niter did not come into use until early in the fourteenth century (for... 

The combined volume of all the billions of open rooms" in the hexagonal ice crystals of a piece of ice is equal to the volume of the part of the ice that extends above water when ice floats. When the ice melts, the open spaces are exaedy filled in by the amount of ice that extends above the water level. This is why the water level doesn t rise when ice in a glass of ice water melts—the melting ice caves in and exactly fills the open spaces. 

---