Quiet Sun observations of the Ali autoionization lines λ1932 and λ1936     

J. W. Cook  O. Kjeldseth Moe 《Solar physics》1982,76(1):109-116

We present quiet Sun observations obtained during a rocket flight of the Al i autoionization lines 1932 and 1936 at solar pointings ranging from = 0.73 out to the visible limb. Absolute intensities are estimated to be accurate to approximately ±20%. These lines progressively weaken with decreasing but never go into emission before finally disappearing with the continuum just beyond the visible solar limb. The observations are compared with LTE line profiles computed through the quiet Sun atmosphere of Vernazza et al. (1976). We discuss several areas of disagreement between the synthetic and observed profiles.  相似文献   

Successful Use of an Innovative Horizontal/Vertical Well Couplet in Fractured Bedrock to Intercept a Mobile Gasoline Plume     

Dana Carlisle  David A. Cook  James A. Miller 《Ground Water Monitoring & Remediation》2002,22(2):82-87

The horizontal directional drilling (HDD) technology was successfully used in a fracture-controlled sandstone matrix to intercept a gasoline plume and create a 150-foot-long hydrodynamic barrier preventing seepage of gasoline and contaminated ground water into a salmon-bearing stream within a public park. A 36-foot-deep vertical recovery well (VW) intercepts the central low point of the 420-foot-long HDD borehole to pump recovered fluids. Contaminant seepage into the creek ceased within hours of starting up the HDD/VW interceptor system in August 1999. Approximately 325 gallons of gasoline and 2 million gallons of contaminated ground water have been recovered to date.  相似文献   

Combining dissolved, suspended and bed load stream geochemistry to explore for volcanic massive sulfide deposits: Big Salmon Complex, northern British Columbia     

Kevin Telmer  Heidi E. Pass  Stephen Cook 《Journal of Geochemical Exploration》2002,75(1-3)

Exploration successes for volcanogenic massive sulfide (VMS) deposits, such as Kudz Ze Kayah, Wolverine and Fyre Lake in the Yukon–Tanana Terrane and Slide Mountain Terrane (southern Yukon Territory) have spurred interest in the correlative rocks in the Big Salmon Complex in northern British Columbia. In an effort to further the utility of multi-media stream geochemistry in exploration frontiers that are forested, heavily drift covered, or buried, the primary streams of 19 watersheds from the East Teslin Lake (National Topographic System (NTS): 104N/9, 16) and Teh Creek areas (NTS: 104O/11, 12, 13, 14) of the Big Salmon Complex were analyzed for Cu, Pb, and Zn and other parameters in the dissolved load, suspended load and bed load. Traditionally, exploration based on stream geochemistry has employed the bed load and more recently the dissolved load chemistry, but almost never the suspended load despite strong differences in the geochemical signatures of the three media. Here, we document that copper, lead, and zinc partition into the dissolved, suspended, and bed loads differently and that the magnitude of anomalies is different for each media. The adsorbing capacity of the suspended load may make it a more sensitive indicator of mineral deposits on a regional basis than either the trace-element-poor dissolved load or the bulk-rock-diluted bed load which are likely better indicators of local mineralization. It is clear that each phase contributes unique information about the distribution of elements in the watershed that could be considered in exploration models.We also show that summing standardized element concentrations and summing the sums across media appears to be an effective method to reduce the data without loss of important information. We likewise investigated the utility of calculating major element normalized enrichments for exploration and find that it is a promising approach.  相似文献   

Development of the HEFT and NuSTAR focusing telescopes     

Fiona A. Harrison  Finn E. Christensen  William Craig  Charles Hailey  Wayne Baumgartner  C. M. H. Chen  James Chonko  W. Rick Cook  Jason Koglin  Kristin-Kruse Madsen  Michael Pivavoroff  Steven Boggs  David Smith 《Experimental Astronomy》2005,20(1-3):131-137

Hard X-ray/soft gamma-ray astrophysics is on the verge of a major advance with the practical realization of technologies capable of efficiently focusing X-rays above 10 keV. Hard X-ray focusing telescopes can achieve orders of magnitude improvements in sensitivity compared to the instruments based on coded apertures and collimated detectors that have traditionally been employed in this energy band. Compact focal planes enable high-performance detectors with good spectral resolution to be employed in efficient, low-background configurations. We have developed multilayer coated grazing incidence optics and solid state Cadmium Zinc Telluride focal plane systems for the High Energy Focusing Telescope (HEFT) balloon-borne experiment, and for the Nuclear Spectroscopic Telescope Array (NuSTAR) Small Explorer satellite. In this paper we describe the technologies, telescope designs, and performance of both experiments.  相似文献   

Effect of mining and related activities on the sediment trace element geochemistry of lake coeur D'Alene,idaho, USA. Part I: Surface sediments     

Arthur J. Horowitz  Kent A. Elrick  Robert B. Cook 《水文研究》1993,7(4):403-423

During the summer of 1989 surface sediment samples were collected in Lake Coeur d'Alene, the Coeur d'Alene River and the St Joe River, Idaho, at a density of approximately one sample per square kilometre. Additional samples were collected from the banks of the South Fork of the Coeur d'Alene and the Coeur d'Alene Rivers in 1991. All the samples were collected to determine trace element concentrations, partitioning and distribution patterns, and to relate them to mining, mining related and discharge operations that have occurred in the Coeur d'Alene district since the 1880s, some of which are ongoing. Most of the surface sediments in Lake Coeur d'Alene north of Conkling Point and Carey Bay are substantially enriched in Ag, As, Cu, Cd, Hg, Pb, Sb and Zn relative to unaffected sediments in the southern portion of the lake near the St Joe River. All the trace element enriched sediments are extremely fine grained (mean grain sizes « 63 μm). Most of the enriched trace elements, based on both the chemical analyses of separated heavy and light mineral fractions and a two step sequential extraction procedure, are associated with an operationally defined Fe oxide phase; much smaller percentages are associated either with operationally defined organics/sulphides or refractory phases. The presence, concentration and distribution of the Fe oxides and heavy minerals indicates that a substantial portion of the enriched trace elements are probably coming from the Coeur d'Alene River, which is serving as a point source. Within the lake, this relatively simple point source pattern is complicated by a combination of (1) the formation of trace element rich authigenic Fe oxides that appear to have reprecipitated from material solubilized from anoxic bed sediments and (2) physical remobilization by currents and wind driven waves. The processes that have caused the trace element enrichment in the surface sediments of Lake Coeur d'Alene are likely to continue for the foreseeable future.  相似文献   

Burial-exhumation history of the central Apennines (Italy), from the foreland to the chain building: thermochronological and geological data     

G. Rusciadelli  M.G. Viandante  F. Calamita  A.C. Cook 《地学学报》2005,17(6):560-572

A clear correlation between regional unconformities and related exhumation events was documented by thermochronological and geological data in the central Apennines. This approach allowed: (i) two major exhumation episodes to be identified, corresponding to turning points in the long-term burial history, from rifting to convergent margin development, and (ii) a quantification of the amount of section removed during the two exhumation events. The first exhumation event was connected with the foreland buckling process associated with the coupling between the Alpine–Apennines system, the Dinarides chain and their common foreland. During the Neogene a thrust-system development, the superposition of an allochthonous unit is envisaged to explain the second palaeoheating event. The dismantling of this additional load in central Apennines has been related to the formation of the Middle Pliocene Unconformity, during the development of the Pliocene–Quaternary frontal thrust of the Apennine Chain.  相似文献   

A review of coastal dunebuilding in Eastern Australia     

P. G. Cook 《The Australian geographer》1986,17(2):133-143

The distribution of transgressive coastal sand dunes in eastern New South Wales and Queensland is summarised and the factors involved in transgressive dune initiation are reviewed. On the basis of radiocarbon and pedological evidence, it is suggested that episodes of transgressive dune instability have been synchronous over large areas. Widespread sand blowing appears to have taken place in the early Holocene between 9,000 and 7,000 years ago. Instability was also widespread between 3,500 and 2,000 years ago and within the last thousand years. Possible causes of dune instability are considered.  相似文献   

Deliberate omission or unfortunate oversight: Should stygofaunal surveys be included in routine groundwater monitoring programs?     

Moya Tomlinson  Andrew J. Boulton  Peter J. Hancock  Peter G. Cook 《Hydrogeology Journal》2007,15(7):1317-1320

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I/I ratios in surface waters of the English Lake District     

M. Atarashi-Andoh  C. Schnabel  G. Cook  A.B. MacKenzie  A. Dougans  R.M. Ellam  S. Freeman  C. Maden  V. Olive  H.-A. Synal  S. Xu 《Applied Geochemistry》2007

Accelerator Mass Spectrometry (AMS) was used to measure ¹²⁹I/¹²⁷I ratios in surface sea, lake, and river water samples collected in 2004 and 2005 from the English Lake District and from SW Scotland, areas which are in relatively close proximity to the Sellafield nuclear fuel reprocessing plant in NW England. The ¹²⁹I/¹²⁷I ratios in surface water collected from the shore of the Irish Sea were in the range 2.8 × 10⁻⁶ to 8.2 × 10⁻⁶. These ratios are one order of magnitude higher than that of seawater collected from the Irish Sea in 1992, correlating with the increase in ¹²⁹I content of the Sellafield liquid effluent discharge over the last decade. The ¹²⁹I/¹²⁷I ratios in lakes in the Lake District were in the range 0.7 × 10⁻⁶ to 6.4 × 10⁻⁶ and decreased exponentially as a function of distance from Sellafield. Consideration of the relative variation of stable I concentrations and ¹²⁹I/¹²⁷I ratios suggests that Sellafield gaseous discharges may be the dominant source of ¹²⁹I to the lakes.  相似文献   

Odd zonal harmonics in the geopotential, from analysis of 28 satellite orbits     

D. G. King-Hele  C. J. Brookes  G. E. Cook 《Geophysical Journal International》1981,64(1):3-30

Summary. The geopotential is usually expressed as an infinite series of spherical harmonics, and the odd zonal harmonics are the terms independent of longitude and antisymmetric about the equator: they define the 'pear-shape' effect. The coefficients J ₃, J ₅, J ₇, … of these harmonics have been evaluated by analysing the variations in eccentricity of 28 satellite orbits from near-equatorial to polar. Most of the orbits from our previous determination in 1974 are used again, but three new orbits are added, including two at inclinations between 62° and 63°, which have been specially observed for more than five years by the Hewitt cameras. With the help of the new orbits and revised theory, we have obtained sets of J -coefficients with standard deviations about 40 per cent lower than before. A 9-coefficient set is chosen as representative, and is as follows (all × 10⁹): J ₃=– 2530 ± 4, J ₅=–245 ± 5, J ₇=–336 ± 6, J ₉=–90 ± 7, J ₁₁= 159 ± 9, J ₁₃=–158 ± 15, J ₁₅=– 20 ± 15, J ₁₇=– 236 ± 14, J ₁₉=– 27 ± 19. With this set of values, the pear-shape asymmetry of the geoid (north polar minus south polar radius) amounts to 45.1 m instead of the previous 44.7 m. The accuracy of the longitude-averaged geoid profile is estimated as 50 cm, except at latitudes above 86°. The geoid profile and predicted amplitude of the oscillation in eccentricity are compared with those from other sources.  相似文献