Near- and mid-infrared imaging polarimetry of NGC 1068     

S. L. Lumsden  T. J. T. Moore  C. Smith  T. Fujiyoshi  J. Bland-Hawthorn  M. J. Ward 《Monthly notices of the Royal Astronomical Society》1999,303(2):209-220

  相似文献   

Optical and infrared observations of the luminous quasar PDS 456: a radio-quiet analogue of 3C 273?     

Chris Simpson  Martin Ward  Paul O'Brien  James Reeves 《Monthly notices of the Royal Astronomical Society》1999,303(2):L23-L28

  相似文献   

All-cis hentriaconta-9,15,22-triene in microbial mats formed by the phototrophic prokaryote Chloroflexus.     

M T van der Meer  S Schouten  D M Ward  J A Geenevasen  J S Sinninghe Damste 《Organic Geochemistry》1999,30(12):1585-1587

All-cis hentriaconta-9,15,22-triene (I) has been isolated from Chloroflexus mats, Yellowstone National Park (USA), and identified by GC-(HR)MS analysis of I and its hydrogenated and DMDS-derivatized products and by 1H and 13C NMR spectroscopy.  相似文献   

Chemical composition of macerals in bituminous coals of the Gunnedah Basin, Australia, using electron microprobe analysis techniques     

Colin R. Ward  Lila W. Gurba 《International Journal of Coal Geology》1999,39(4):415

The chemical composition of the organic matter in the principal macerals of high-volatile bituminous coals from the Gunnedah Basin, New South Wales (Rv_max of telocollinite between 0.6 and 1.1%) has been evaluated from polished section specimens using an electron microprobe technique. Highest proportions of carbon occur in the inertinite macerals, especially fusinite and secretinite (formerly resino-sclerotinite), as well as in sporinite; lowest proportions of carbon occur in the different macerals of the vitrinite group. Oxygen shows the reverse trend, being most abundant in vitrinite and least abundant in the inertinite components, whereas sulphur is lowest in the inertinites and highest in the liptinite (mainly sporinite) present. Evaluations of maceral composition, using the carbon content of telocollinite as a rank indicator, show that carbon is more abundant in both sporinite and semifusinite, relative to vitrinite, in low-rank high-volatile bituminous coals. The difference decreases with increasing rank, and the proportion of carbon in telocollinite becomes essentially the same as that in sporinite and semifusinite at carbon contents of about 89 and 91%, respectively. The carbon content of fusinite and secretinite, on the other hand, does not seem to vary appreciably with rank advance. No significant difference in composition occurs in the rank range studied between the three vitrinite varieties present, desmocollinite, telocollinite and a more highly reflecting telocollinite resembling pseudovitrinite. No evidence was found to indicate a higher hydrogen content, relative to telocollinite, for the vitrinite matrix of desmocollinite.  相似文献   

Mineral matter and trace elements in coals of the Gunnedah Basin, New South Wales, Australia     

Colin R. Ward  D. A. Spears  Carol A. Booth  Ian Staton  Lila W. Gurba 《International Journal of Coal Geology》1999,40(4):2843

The concentrations of major and trace inorganic elements in a succession of Permian coals from the Gunnedah Basin, New South Wales, have been determined by X-ray fluorescence techniques applied to both whole-coal and high-temperature ash samples. The results have been evaluated in the light of quantitative data on the minerals in the same coals, determined from X-ray diffraction study of whole-coal samples using a Rietveld-based interpretation program ( ™), to determine relationships of the trace elements in the coals to the mineral species present. Comparison of the chemical composition of the coal ash interpreted from the quantitative mineralogical study to the actual ash composition determined by XRF analysis shows a high degree of consistency, confirming the validity of the XRD interpretations for the Gunnedah Basin materials. Quartz, illite and other minerals of detrital origin dominate the coals in the upper part of the sequence, whereas authigenic kaolinite is abundant in coals from the lower part of the Permian succession. These minerals are all reduced in abundance, however, and pyrite is a dominant constituent, in coals formed under marine influence at several stratigraphic levels. Calcite and dolomite occur as cleat and fracture infillings, mostly in seams near the top and bottom of the sequence. The potassium-bearing minerals in the detrital fraction are associated with significant concentrations of rubidium, and the authigenic kaolinite with relatively high proportions of titanium. Zirconium is also abundant, with associated P and Hf, in the Gunnedah Basin coal seams. Relationships exhibited by Ti, Zr, Nd and Y are consistent with derivation of the original sediment admixed with the seams from an acid volcanic source. Pyrite in the coals is associated with high concentrations of arsenic and minor proportions of thallium; no other element commonly associated with sulphides in coals, however, appears to occur in significant proportions with the pyrite in the sample suite. Small concentrations of Cl present in the coal are inversely related to the pyrite content, and appear to represent ion-exchange components associated with the organic matter. Strontium and barium are strongly associated with the cleat-filling carbonate minerals. Ge and Ga appear to be related to each other and to the coal's organic matter. Cr and V are also related to each other, as are Ce, La, Nd and Pr, but none of these show any relationship to the organic matter or a particular mineral component.  相似文献   

All-cis hentriaconta-9,15,22-triene in microbial mats formed by the phototrophic prokaryote Chloroflexus     

Marcel T. J. van der Meer  Stefan Schouten  David M. Ward  Jan A. J. Geenevasen  Jaap S. Sinninghe Damst 《Organic Geochemistry》1999,30(12):3850

All-cis hentriaconta-9,15,22-triene (I) has been isolated from Chloroflexus mats, Yellowstone National Park (USA), and identified by GC–(HR)MS analysis of I and its hydrogenated and DMDS-derivatized products and by ¹H and ¹³C NMR spectroscopy.  相似文献   

Monitoring Growth in Rapidly Urbanizing Areas Using Remotely Sensed Data     

Douglas Ward  Stuart R. Phinn  Alan T. Murray 《The Professional geographer》2000,52(3):371-386

Urbanization and the ability to manage for a sustainable future present numerous challenges for geographers and planners in metropolitan regions. Remotely sensed data are inherently suited to provide information on urban land cover characteristics, and their change over time, at various spatial and temporal scales. Data models for establishing the range of urban land cover types and their biophysical composition (vegetation, soil, and impervious surfaces) are integrated to provide a hierarchical approach to classifying land cover within urban environments. These data also provide an essential component for current simulation models of urban growth patterns, as both calibration and validation data. The first stages of the approach have been applied to examine urban growth between 1988 and 1995 for a rapidly developing area in southeast Queensland, Australia. Landsat Thematic Mapper image data provided accurate (83% adjusted overall accuracy) classification of broad land cover types and their change over time. The combination of commonly available remotely sensed data, image processing methods, and emerging urban growth models highlights an important application for current and next generation moderate spatial resolution image data in studies of urban environments.  相似文献   

Hydraulic Fracturing Wastewater: Treatment,Reuse, and Disposal          下载免费PDF全文

Kathryn Ward 《Ground water》2017,55(6):775-775

  相似文献   

Impacts of unconstrained effort: Lessons from a rock lobster (Jasus edwardsii) fishery decline in the northern zone management region of South Australia     

Adrian Linnane  Sean Sloan  Richard McGarvey  Tim Ward 《Marine Policy》2010

The Northern Zone rock lobster fishery of South Australia is expansive, covering an area of ∼207,000 km². From 1970 to 2002 it was managed under input controls that relied heavily on restrictions to days-at-sea and size limits. In 2003, output controls in the form of individual transferable quotas with a total allowable commercial catch were also introduced. Fishery performance from 1980 to 2007 was analysed based on catch data and model outputs. Trends in catch and effort increased through the 1980s and 1990s while nominal catch rate remained relatively stable. However, from 1999 to 2003 catch decreased by 49% from 1001 to 503 ton and has remained at <500 ton since. Importantly, nominal effort did not decline comparatively, decreasing by only 12% from 1999 to 2007. Consequently, nominal catch rate decreased by 47.5% from 1.43 to 0.75 kg/potlift, over the same period. Logbook data revealed strong evidence of spatial expansion through the 1980s and 1990s which is likely to have masked declining lobster abundance and contributed to a “hyperstability” scenario in catch rates. It is suggested that increasing effective effort, driven by advances in fishing technology and vessel design, fuelled this expansion. Model outputs, which account for increases in effective effort, indicate that biomass has decreased by ∼68% since the 1980s. The results highlight the limitations associated with input controls in controlling effort during periods of spatial expansion. Further evidence from puerulus settlement data stresses the importance of conservative quotas for lobster fisheries where annual recruitment is low or highly sporadic.  相似文献   

RE J1034+396: the origin of the soft X-ray excess and quasi-periodic oscillation     

Matthew Middleton  Chris Done  Martin Ward  Marek Gierli&#;ski  Nick Schurch 《Monthly notices of the Royal Astronomical Society》2009,394(1):250-260

The X-ray quasi-periodic oscillation (QPO) seen in RE J1034+396 is so far unique amongst active galactic nuclei (AGN). Here, we look at another unique feature of RE J1034+396, namely its huge soft X-ray excess, to see if this is related in any way to the detection of the QPO. We show that all potential models considered for the soft energy excess can fit the 0.3–10 keV X-ray spectrum, but the energy dependence of the rapid variability (which is dominated by the QPO) strongly supports a spectral decomposition where the soft excess is from low-temperature Comptonization of the disc emission and remains mostly constant, while the rapid variability is produced by the power-law tail changing in normalization. The presence of the QPO in the tail rather than in the disc is a common feature in black hole binaries (BHBs), but low-temperature Comptonization of the disc spectrum is not generally seen in these systems. The main exception to this is GRS 1915+105, the only BHB which routinely shows super-Eddington luminosities. We speculate that the super-Eddington accretion rates lead to a change in disc structure, and that this also triggers the X-ray QPO.  相似文献