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Full-Text Articles in Physical Sciences and Mathematics
Botanical Evidence For Holocene Movement Of Rock Streams In Arkansas, S. Marie Lookingbill, Malcolm K. Cleaveland, Margaret J. Guccione
Botanical Evidence For Holocene Movement Of Rock Streams In Arkansas, S. Marie Lookingbill, Malcolm K. Cleaveland, Margaret J. Guccione
Journal of the Arkansas Academy of Science
Botanical studies of rock streams on the western half of Rich Mountain and on the north slope of Mt. Magazine in Arkansas question the common presumption that such streams require periglacial conditions to form, and are now inactive relict features in this area. Trees along the margins of the streams examined show abundant evidence of trauma resulting from Late Holocene movement, in the form of bent and tilted stems. Cross sections of trees demonstrate marked eccentric growth associated with tilting and cambial trauma associated with corrasion by rocks. That this damage is not the result of excessive snow loading is …
Physiography And Hydrology Of The Upper Saline River, Saline And Garland Counties, Arkansas, John D. Rickett
Physiography And Hydrology Of The Upper Saline River, Saline And Garland Counties, Arkansas, John D. Rickett
Journal of the Arkansas Academy of Science
The Saline River is one of two significant river systems in Arkansas that does not have a major impoundment. In the interest of continuing this status, this project was conducted. Thirty-five sites on the four major and six minor tributaries of the upper saline River, Saline and Garland Counties, Arkansas, were visited a total of 58 times between 24 January 1985 and 21 November 1986. Habitat quality was assessed by measuring twelve physicochemical features and flow parameters, analyzing substrate composition and describing stream morphometry. Physicochemical measurements were within the limits of good quality habitat, and most of the readings were …
Textural And Lithologic Differences Of Cretaceous, Tertiary, And Quaternary Gravels Of South Arkansas, Lesli Wood
Textural And Lithologic Differences Of Cretaceous, Tertiary, And Quaternary Gravels Of South Arkansas, Lesli Wood
Journal of the Arkansas Academy of Science
Stream gravels have been derived from the Ouachita Mountains since at least Cretaceous times. Past studies have assigned ages to gravel deposits in the basins of the Saline and Little Missouri Rivers on the basis of altitude above local floodplains. This study examines the lithologies and textures of seven gravel outcrops ranging in age from Cretaceous to Quaternary to determine whether any patterns of variation based on assigned ages, variable sources, or precise depositional setting can be discerned. No variation patterns could be found for size distributions of sand-sized and larger fractions. However, the amount of silt-clay matrix decreases through …
Improved Synthesis Of 5-Methylbenz(A)Anthracene, Jia Che, Dominic T.C. Yang
Improved Synthesis Of 5-Methylbenz(A)Anthracene, Jia Che, Dominic T.C. Yang
Journal of the Arkansas Academy of Science
A revised synthesis of 5-methylbenz(a)anthracene is reported. It involves only three simple and convenient steps starting from a commercially available compound, and gives a 82% overall yield. Bromination of 5-methylbenz(a)anthracene with N-bromosuccinimide (NBS) in carbon tetrachloride furnishes 5-bromomethylbenz(a)anthracene in a 92% yield. When bromination is carried out using dimethylformamide as the solvent, 7-bromo-5-methylbenz(a)anthracene is formed as the exclusive product.