Helium isotopes in some historical lavas from Mount Vesuvius     

D.W. Graham  P. Allard  C.R.J. Kilburn  F.J. Spera  J.E. Lupton   《Journal of Volcanology and Geothermal Research》1993,58(1-4)

³He/⁴He ratios in lavas erupted during the last 360 years at Mt. Vesuvius are between 2.2 and 2.7 R_A (R_A = atmospheric ratio of 1.39 × 10⁻⁶), and are among the lowest values measured in young volcanic rocks. They are also identical to values measured in summit crater fumaroles sampled during 1987–1991. This agreement indicates that the ³He/⁴He ratio in the crater fumaroles faithfully tracks the magmatic value. The relatively low and uniform ³He/⁴He ratio in the lavas reflects either a mantle source enriched in (U + Th)/³He, or a mixture of magmatic and crustal components.  相似文献   

A design study of an energy-dissipating cladding system     

Julie Mark Cohen  Graham H. Powell 《地震工程与结构动力学》1993,22(7):617-632

A design study has been conducted to explore the use of structural cladding panels with energy-dissipating cladding-to-frame connections for seismic-resistant design. The study identifies several issues involved in the modelling and analysis of frames with energy-dissipating cladding-to-frame connections, establishes concepts for design, and provides a preliminary assessment of the force and deformation demands that are likely to be placed on panels and connections. Non-linear dynamic analyses indicate that the clad frames perform well, based on observations about maximum interstorey drifts, maximum plastic hinge rotations in the frames, and maximum ductility demands on the cladding-to-frame connections.  相似文献   

Glaciotectonic structures and their relation to topography at Dinas Dinlle,Arvon, northwest Wales     

Charles Harris  Peter J. Brabham  Graham D. Williams 《第四纪科学杂志》1995,10(4):397-397

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THE METEORITICAL SOCIETY     

A.L. Graham 《Meteoritics & planetary science》1980,15(1):93-103

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Cryostorage of hepatic microsomes from two marine mammal species: effects on cytochrome P450-monooxygenase activities and content     

Tilley RE  Kemp GD  Hall AJ 《Marine pollution bulletin》2003,46(5):654-658

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Impacts of the Jessica oil spill: an introduction     

Edgar GJ  Snell HL  Lougheed LW 《Marine pollution bulletin》2003,47(7-8):273-275

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Seismic Hazard and Risk Assessment for Tulbagh,South Africa: Part I – Assessment of Seismic Hazard     

Kijko  A.  Retief  S. J. P.  Graham  G. 《Natural Hazards》2002,26(2):175-201

In this part of our study the probabilistic seismic hazard analysis (PSHA) for Tulbagh was performed. The applied procedure is parametric and consists essentially of two steps. The first step is applicable to the area in the vicinity of Tulbagh and requires an estimation of the area-specific parameters, which, in this case, is the mean seismic activity rate, , the Gutenberg-Richter parameter, b, and the maximum regional magnitude, m_max. The second step is applicable to the Tulbagh site, and consists of parameters of distribution of amplitude of the selected ground motion parameter. The current application of the procedure provides an assessment of the PSHA in terms of peak ground acceleration (PGA) and spectral acceleration (SA). The procedure permits the combination of both historical and instrumental data. The historical part of the catalogue only contains the strongest events, whereas the complete part can be divided into several subcatalogues, each assumed complete above a specified threshold of magnitude. In the analysis, the uncertainty in the determination of the earthquake was taken into account by incorporation of the concept of `apparent magnitude'. The PSHA technique has been developed specifically for the estimation of seismic hazard at individual sites without the subjective judgement involved in the definition of seismic source zones, when the specific active faults have not been mapped or identified, and where the causes of seismicity are not well understood. The results of the hazard assessment are expressed as probabilities that specified values of PGA will be exceeded during the chosen time intervals, and similarly for the spectral accelerations. A worst case scenario sketches the possibility of a maximum PGA of 0.30g. The results of the hazard assessment can be used as input to a seismic risk assessment.  相似文献   

The influence of diet on comparative trace metal cadmium,copper and zinc accumulation in Thais clavigera (Gastropoda: Muricidae) preying on intertidal barnacles or mussels     

Blackmore G  Morton B 《Marine pollution bulletin》2002,44(9):870-876

The influence of diet on comparative metal accumulation was investigated using a predatory muricid gastropod Thais clavigera. Individuals were fed for up to 56 days on either barnacles, i.e., Tetraclita squamosa, or mussels, i.e., Perna viridis, collected from metal-contaminated and clean sites. Barnacles and mussels have contrasting metal handling strategies and, therefore, different body concentrations, intracellular distributions and detoxification systems. Field collection of prey items that accumulated body metal concentrations over a lifetime of exposure allowed bioavailability to the predator, T. clavigera, to be assessed naturally, which may not be the case for prey exposed to metals for a short time in the laboratory. T. clavigera that was fed cadmium- and copper-contaminated barnacles or mussels ingested significantly greater amounts compared to those fed conspecifics collected from clean locations. T. clavigera body cadmium and copper concentrations were not, however, significantly different between individuals fed either contaminated or clean prey. Amount of zinc ingested was similar in mussels collected from clean and contaminated environments but much less when compared to the barnacle prey. The body concentrations of zinc in T. clavigera fed mussels collected from both sites fell. In contrast, the amount of zinc ingested from barnacle prey was significantly greater from those collected from the metal-contaminated site as compared to the clean one. This was reflected as significantly greater body zinc concentrations in T. clavigera fed contaminated barnacles compared to those fed clean individuals. Copper and zinc accumulation from prey was, therefore, complex. It varied between metal and between prey type, but appeared to be related to the amount ingested and the metal handling strategy of the prey.  相似文献   

Assessing climate change impacts on hydrology from an ensemble of regional climate models,model scales and linking methods – a case study on the Lule River basin     

L. Phil Graham  Johan Andréasson  Bengt Carlsson 《Climatic change》2007,81(1):293-307

This paper investigates how using different regional climate model (RCM) simulations affects climate change impacts on hydrology in northern Europe using an offline hydrological model. Climate change scenarios from an ensemble of seven RCMs, two global climate models (GCMs), two global emissions scenarios and two RCMs of varying resolution were used. A total of 15 climate change simulations were included in studies on the Lule River basin in Northern Sweden. Two different approaches to transfer climate change from the RCMs to hydrological models were tested. A rudimentary estimate of change in hydropower potential on the Lule River due to climate change was also made. The results indicate an overall increase in river flow, earlier spring peak flows and an increase in hydropower potential. The two approaches for transferring the signal of climate change to the hydrological impacts model gave similar mean results, but considerably different seasonal dynamics, a result that is highly relevant for other types of climate change impacts studies.  相似文献   

Platinum-group elements (Ir,Pd, Pt and Rh) in road-deposited sediments in two urban watersheds,Hawaii     

Ross A. Sutherland  D. Graham Pearson  Chris J. Ottley 《Applied Geochemistry》2007

This study represents the first detailed investigation of platinum-group elements (PGEs) in road-deposited sediment (RDS) in Hawaii, USA. Thirty-three sample locations, in two urban watersheds in Honolulu, Oahu, Hawaii were sampled. The <63 μm fraction of RDS was digested with aqua regia, followed by matrix separation with Dowex AG50-X8 cation exchange resin. PGEs were analyzed with inductively coupled plasma-mass spectrometry (ICP-MS) equipped with a desolvating nebulizer. Concentrations of Rh, Pd and Pt in residential streets reached 64, 105 and 506 ng/g, respectively. Maximum enrichment ratios, computed as RDS concentrations relative to baseline values, exceeded 400, indicating a significant anthropogenic signal with the sequence Rh > Pt > Pd. Iridium concentrations were uniformly low <1 ng/g, and enrichment ratios support a geogenic source. Significant interelement PGE correlations (Pd–Pt–Rh), combined with the magnitude of PGE pair-wise ratios (Pt/Pd, Pt/Rh and Pd/Rh), and relative percentages comparable to European RDS and roadside soil in Indiana, USA all suggest an automobile source. Attrition of PGE-loaded automobile catalytic converters and subsequent loss to the environment by exhaust emissions explains the significant environmental signal of PGEs in road environments of Hawaii. Further PGE work is required to quantify urban transport paths as PGEs are known to bioaccumulate, cause cellular damage and may have detrimental human health effects.  相似文献