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David A. Chisholm 《The Australian geographer》1995,26(2):156-163
Leeton, a town of 6000 in the Murrumbidgee Irrigation Area, has in recent times suffered major economic upheaval. In 1993 the Letona Co‐operative stone fruit cannery, Leeton's masthead industry since 1921, was placed in receivership and closed after extensive search for a new investor in stone fruit processing failed. The removal of a substantial income stream from the local community has placed great stress on Leeton's economic and social fabric. However, the town in recent years has developed an economy that is no longer completely reliant on a narrow range of agricultural processing and service activities. Utilising factors of location, irrigation‐supported production flexibility and security, cheap land and utilities, and a stable and productive workforce, the combined efforts of the Leeton Shire Council, local community groups, the Riverina Development Board, and State Government departments have attracted a range of new industries to the town and shire over the past decade. It is these industries that will allow Leeton to survive the loss of Letona, sustain its economy and look to the future with confidence. 相似文献
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J. E. Chisholm 《Physics and Chemistry of Minerals》1985,12(3):185-190
The behaviour of the O-H stretching infrared spectra of the synthetic olivenite-adamite series described by Brathwaite (1983) is accounted for in terms of the crystal structure and cation distribution. There are three absorption bands: Two at 3,540 and 3,510 cm?1 correspond to OH groups bonded to Zn3 and CuZn2 respectively. The third band corresponds to OH groups bonded to both combinations Cu2Zn and Cu3 and its frequency varies with the proportions of those two combinations. Preferential occupation of the five-fold site by Zn is confirmed from its effect on the infrared spectra, the ratio ZnV/ZnVI being roughly 4:1. There is evidence for clustering of Zn into Zn3 groups around OH. Differences in the degree of segregation and clustering of Zn will affect the infrared spectra of natural olivenites and adamites and this may limit the usefulness of infrared spectroscopy as a determinative method. 相似文献
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David A. Jay Philip M. Orton Thomas Chisholm Douglas J. Wilson Annika M. V. Fain 《Estuaries and Coasts》2007,30(6):1106-1125
Estuarine turbidity maxima (ETM) retain suspended particulate matter (SPM) through advection, settling, aggregation, and nonlinearities
in bed processes, but the relative importance of these processes varies strongly between systems. Observations from two strongly
advective systems (the Columbia and Fraser Rivers) are used to investigate seasonal cycles of SPM retention and the effects
of very high flows. Results for the Fraser and Columbia plus literature values for 13 other estuaries illustrate the applicability
of scaling parameters and the response of ETM phenomena to a range of river flow (U
r
) levels and tidal forcing. The most efficient trapping (represented by Trapping EfficiencyE, the ratio of maximum ETM concentration to the source SPM concentration) occurs for low ratios of river flow to tidal current
amplitude (UT), represented by low values of the Supply number Sr.E in the Columbia is found to be maximal in a null zone where advection or tidal asymmetry (represented by Advection numberA) is weak(A ∼ 0). The ratio of aggregation to disaggregation (the Floc number Θ) is maximal on neap tides, while the ratio of erosion to
deposition (the Erosion number P) is maximal on spring tides. The ratio of settling velocity to vertical mixing (Rouse numberP) is relatively constant in the Columbia ETM(P ∼ 0.7), because particle settling velocity and turbulence levels adjust together. Assuming that this result applies broadly,
scaling variables and data are combined to express ETM properties in terms of the friction velocity (U*),U
r
, andU
T
, allowing a considerable simplification of the parameters used to describe ETM. 相似文献
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GEOMORPHOLOGICAL PHOTOGRAMMETRY 总被引：1，自引：0，他引：1
The broad requirements of the geomorphologist for original mapping are reviewed. The extent to which aerial photogrammetry can meet these requirements is exemplified through typical approaches and mapping products in fluvial, coastal and glacial specialisms. 相似文献
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N. W. T. Chisholm 《The Photogrammetric Record》1990,13(76):533-560
This study of coastal air survey draws together the main characteristics of the coastal zone, scientific sites of interest, statutory spheres of responsibility, existing coastal photography and survey, and evidence of survey practices by many with responsibilities in these environments. In contrast to the surveyor/photogrammetrist steeped in survey techniques and map use, the majority of people who commission and use air photographs and photogrammetric mapping have very different backgrounds and interests and have widely differing objectives. They come largely from the disciplines of economics, planning, engineering, geography, biological sciences and accountancy. They, too, have their own view of the value of air survey and the analysis here of the trends in demand and use for such material suggests that these sources of information play only a minor and occasional part in their everyday work. 相似文献
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Chisholm Nicole Nagare Baban Wainwright Charlotte Creegan Ed Salehpoor Leyla VandenBoer Trevor C. Bullock Terry Croft Betty Lesins Glen Osthoff Hans Fernando H. J. S. Chang Rachel Y.-W. 《Boundary-Layer Meteorology》2021,181(2-3):345-364
Boundary-Layer Meteorology - Marine aerosols play an important role in the Earth’s climate, but their effects remain highly uncertain due to a poor understanding of their sources, properties,... 相似文献
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N. W. T. Chisholm 《The Photogrammetric Record》1983,11(61):124-125