Fissure formation

In contrast to UC, the pattern of inflammation in CD is described as discontinuous. Areas of inflammation are intermixed with areas of normal GI mucosa, resulting in characteristic skip lesions. Superficial aphthous ulcers may also develop in the GI mucosa. These ulcers may coalesce into larger linear ulcers, resulting in fissure formation as they increase in depth, giving rise to the characteristic cobblestone pattern observed upon examination of the mucosa. 

Taken together, these biochemical and cellular transformations within the degenerating IVD result in macroscopic changes manifest as a dehydrated and fibrous NP, disorganized AF lamellae, and an inconspicuous boundary between the NP and AF. Concentric and/or radial annular tears, and NP fissure formations are also observed within the severely degenerated IVD, and an overall reduction in the central disc height may occur [11, 31]. Additionally, blood vessels and nerve endings have been found to infiltrate into the center of the disc, which may harbor inflammatory cells and their mediators. 

When a horizontal opening is created in a solid or fissured rock formation, tensile stresses are generated in the roofs of these openings. In a solid formation, the opening may remain stable for various lengths of time. In a fissured formation, or even in a solid formation of weak rock, the opening may cave immediately, or in a short period of time. Rock bolts are widely used in mine tunnels drifts) as a major means of roof support. 

Characterization of Fissures Formation by Image Analysis Techniques... 

Siebenmorgen, T. (., Cooper, N. T. W., Estorninos, L. E., Bautista, R. C., 2007. Kinetics of milled rice fissure formation, in B. R. WeUs rice research studies 2007, AAES Research Series 560 (eds R. (. Norman, J.-F. Meullenet, K. A. K. Moldenhauer). Arkansas Agriculture Experiment Station Publications, Eayetteville, Ark., USA, pp. 275-282. 

Fluorspar occurs in two distinct types of formation in the fluorspar district of southern Illinois and Kentucky in vertical fissure veins and in horizontal bedded replacement deposits. A 61-m bed of sandstone and shale serves as a cap rock for ascending fluorine-containing solutions and gases. Mineralizing solutions come up the faults and form vein ore bodies where the larger faults are plugged by shale. Bedded deposits occur under the thick sandstone and shale roofs. Other elements of value associated with fluorspar ore bodies are zinc, lead, cadmium, silver, germanium, iron, and thorium. Ore has been mined as deep as 300 m in this district. 

One useful classification of graphite depends on the mode of formation that leads to three physically distinct common varieties dake, lump, and amorphous. The term dake is self-explanatory dake forms occur disseminated in rock. Lump graphite occurs in fissure-filled veins in pegmatite dikes, also associated with chip and the rarer needle forms. Amorphous graphite occurs in beds that were once coal, but fine-grained, easily ground vein graphite is also classified as amorphous. 

Underlying geological formations that contain rock fractures or fissures of questionable permeabihty must be permanently sealed to provide a competent barrier to the movement of hquids or gases from the disposal site to usable water. 

Sprung, m. crack, chink, fissure (of strata) fault jump, spring, bounce, ieap (in a curve) break, discontinuity (in spectra) transition (of waves) hop. -bildung,/. crack formation, fissuring. -feder, /. (eiastic) spring. 

Other methods propose to use materials that interact in the fissures of the formation to form a plug of increased strength. Lost circulation additives are sunamarized in Table 1-12. 

A series of test methods and procedures have been developed to measure these phenomena [67]. Cracks should be avoided because these increase the permeability of the cement. The expansion of the cement, without the formation of macro-fissures, depends on the time at which the expanding... 

Boulton, N. S. and Streltsova, T. D., 1977, Unsteady How to a Pumped Well in a Fissured Water-bearing Formation Journal of Hydrology, Vol. 35, pp. 257-269. 

Bituminous sand a formation in which fhe bifuminous material (see Bitumen) is found as a filling in veins and fissures in fractnred rocks or impregnating relatively shallow sand, sandstone, and limestone strata a sandstone reservoir that is impregnated with a heavy, viscons black petroleumlike material that cannot be retrieved throngh a well by conventional production techniqnes. 

Formaldehyde is one of the most common causes of occupational skin disease the major effects of formaldehyde on the skin are irritant dermatitis and allergic contact dermatitis. Irritant dermatitis results from direct injury to the skin and is characterized by redness and thickening of the affected areas. In more severe cases there may be blistering, scaling, and the formation of fissures. 

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