Submerged cylinder wave energy device: theory and experiment     

D.V. Evans  D.C. Jeffrey  S.H. Salter  J.R.M. Taylor 《Applied Ocean Research》1979,1(1):3-12

Linearized water wave theory is used to show that a submerged long circular cylinder suitably constrained by springs and dampers to make small harmonic oscillations, can be extremely efficient in absorbing the energy in an incident regular wave whose crests are parallel to the axis of the cylinder. Experimental results are described which confirm the theory for small amplitude waves and which suggest that the device can still be fairly efficient in waves of moderate amplitude.  相似文献   

The dissociation constants of carbonic acid in seawater at salinities 5 to 45 and temperatures 0 to 45°C     

Rabindra N Roy  Lakshimi N Roy  Kathleen M Vogel  C Porter-Moore  Tara Pearson  Catherine E Good  Frank J Millero  Douglas M Campbell 《Marine Chemistry》1993,44(2-4)

The pK₁^* and pK₂^* for the dissociation of carbonic acid in seawater have been determined from 0 to 45°C and S = 5 to 45. The values of pK₁^* have been determined from emf measurements for the cell: where X is the mole fraction of CO₂ in the gas. The values of pK₂^* have been determined from emf measurements on the cell: The results have been fitted to the equations: where T is the temperature in K, S is the salinity, and the standard deviations of the fits are σ = 0.0048 in lnK₁^* and σ = 0.0070 in lnK₂^*.Our new results are in good agreement at S = 35 (±0.002 in pK₁^*and ±0.005 in pK₂^*) from 0 to 45°C with the earlier results of Goyet and Poisson (1989). Since our measurements are more precise than the earlier measurements due to the use of the Pt, H₂|AgCl, Ag electrode system, we feel that our equations should be used to calculate the components of the carbonate system in seawater.  相似文献   

Water resources sustainability in a globalizing world: who uses the water?          下载免费PDF全文

Megan Konar  Tom P. Evans  Morgan Levy  Christopher A. Scott  Tara J. Troy  Charles J. Vörösmarty  Murugesu Sivapalan 《水文研究》2016,30(18):3330-3336

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Holistic environmental assessment and offshore oil field exploration and production     

Salter E  Ford J 《Marine pollution bulletin》2001,42(1):45-58

According to UK Government surveys, concern for the environment is growing. Environmental regulation of the industry is becoming wider in its scope and tougher in its implementation. Various techniques are available to assess how the industry can drive down its environmental impact and comply with environmental regulation. Environmental Assessments (EA) required by European law do not cover the whole life cycle of the project that they are analysing. Life Cycle Analysis (LCA) was developed to assess the environmental loadings of a product, process or activity over its entire life cycle. It was the first technique used in environmental analysis that adopted what was described as a holistic approach. It fails this approach by not assessing accidental emissions or environmental impacts other than those that are direct. Cost Benefit Analysis (CBA) offers the opportunity to value environmental effects and appraise a project on the basis of costs and benefits. Not all environmental effects can be valued and of those that can there is considerable uncertainty in their valuation and occurrence. CBA cannot satisfactorily measure the total environmental risk of a project. Consequently there is a need for a technique that overcomes the failures of project-level EA, LCA and CBA, and assesses total environmental risk. Many organizations such as, the British Medical Association, the European Oilfield Speciality Chemicals Association, the Royal Ministry of Petroleum and Energy (Norway) and Shell Expro now recognize that a holistic approach is an integral part of assessing total risk. The Brent SPAR case study highlights the interdisciplinary nature required of any environmental analysis. Holistic Environmental Assessment is recommended as such an environmental analysis.  相似文献   

Polarization observations of the radio cores of AGN — I. A sample of quasars     

D. J. Saikia  G. F. Holmes  A. R. Kulkarni  C. J. Salter  & S. T. Garrington 《Monthly notices of the Royal Astronomical Society》1998,298(3):877-887

We present total-intensity and linear-polarization observations at a single epoch for a sample of 11 quasars and one BL Lac object. The data were taken with the VLA A array at λλ 20, 18, 6 and 2 cm. We examine the variation of the degree of polarization, p , and polarization position angle, PA, with wavelength, and attempt to determine the rotation measure, RM, of the cores in these sources. The degree of polarization does not exhibit any systematic variation with wavelength, the median values ranging from 2.3 to 3.5 per cent at the different wavelengths. The variation of PA with λ² is not linear over the entire wavelength range. However, for most sources the λλ 20-, 18- and 6-cm PAs do follow such a linear relationship, yielding a median |RM| of about 15 rad m⁻². In contrast, the λλ 6- and 2-cm observations give a median |RM| of about 129 rad m⁻². The long-wavelength emission is likely to originate from a spatially different part of the milliarcsec-scale jet from the λ 2-cm emission, which could turn over at a higher frequency and is likely to be more compact and located closer to the quasar nucleus. We have attempted to obtain linear fits over the entire wavelength range allowing for n  π ambiguities in the PAs, but the fits are not statistically significant. The low values of RM for these core-dominated sources suggest that either the radio emission from the jet intercepts few of the emission-line clouds and their confining medium, or the clouds have a small filling factor and are possibly magnetically confined.  相似文献   

Johann Georg Goldammer, Valentin V. Furyaev (eds.): Fire in Ecosystems of Boreal Eurasia     

Tara Tchir  Edward A. Johnson 《Climatic change》1998,39(4):731-736

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Performance of seismically loaded shearwalls on nonlinear shallow foundations     

Prishati Raychowdhury  Tara C. Hutchinson 《国际地质力学数值与分析法杂志》2011,35(7):846-858

If utilized, the energy dissipative capability of seismically loaded shallow foundations due to inelastic behavior can result in more economic design, provided the consequences, such as excessive deformations are accounted for. In this article, a Beam‐on‐Nonlinear‐Winkler‐Foundation (BNWF) model is used to assess the performance of shearwall‐foundation systems with different attributes, when subjected to ground motions of varied hazard levels. The numerical study indicates that the force and drift demands to the shearwall reduce significantly, when nonlinear foundation behavior is realized, while permanent settlement is well below the permissible limit. These results support the concept of shallow foundation capacity mobilization in future design. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

A review of marine mammal,sea turtle and seabird bycatch in USA fisheries and the role of policy in shaping management     

Jeffrey E. Moore  Bryan P. Wallace  Rebecca L. Lewison  Ramúnas Žydelis  Tara M. Cox  Larry B. Crowder 《Marine Policy》2009

This paper reviews the available information (observer programs, estimates, statutes, regulations) for bycatch of marine mammals, sea turtles, and seabirds in fisheries of the United States. Goals of the review were to evaluate the state of knowledge of bycatch and the role of existing protective legislation in shaping bycatch management for different taxa. Pressing issues are identified, as well as knowledge gaps and policy limitations that hinder multi-species bycatch reduction. The USA has made important progress toward reducing bycatch in its fisheries, but the efficacy of its management has been limited somewhat by a focus on taxon- and fishery-specific regulation and the lack of consistent mandate across taxa for taking a cumulative perspective on bycatch. Applying consistent criteria across taxa for setting bycatch limits (e.g., extending the approach used for marine mammals to sea turtles and seabirds) would be the first step in a multi-species approach to bycatch reduction. A population-based multi-species multi-gear approach to bycatch would help identify priority areas where resources are needed most and can be used most effectively.  相似文献   

Identifying and removing structural biases in climate models with history matching     

Williamson  Daniel  Blaker  Adam T.  Hampton  Charlotte  Salter  James 《Climate Dynamics》2015,45(5-6):1299-1324

Climate Dynamics - We describe the method of history matching, a method currently used to help quantify parametric uncertainty in climate models, and argue for its use in identifying and removing...  相似文献   

Analytical and numerical investigation of multicomponent multiphase WAG displacements     

Tara LaForce  Kristian Jessen 《Computational Geosciences》2010,14(4):745-754

In this paper the ability of analytical solutions for four-component three-phase flow to predict displacement efficiency in water alternating gas (WAG) injection processes is studied. First analytical solutions for Riemann problems with injection compositions that are the average water and gas mixture for various WAG injection schemes are presented. These solutions are compared to numerical calculations with variable slug sizes and used to explore the effect of slug size, injecting water vs gas first, and the average injection composition on displacement efficiency in compositional WAG schemes. The example model is partially miscible WAG injection of water and CO₂ into an oil reservoir containing C₁₀ and CH₄ with and without a mobile aqueous phase present initially. The trailing end of the water and gas profiles are sensitive to whether water or gas is injected first, but the magnitude of the oil bank and the breakthrough time of the injected fluids are accurately predicted by the analytical solutions, even for displacements where large water and gas slugs are injected. Fluctuations in the saturation and composition profiles resulting from the alternating injection sequence in the WAG simulations appear as super-imposed on top of the sequence of rarefaction and shock waves predicted by analytical solutions. As the number of slugs increases, the effect of alternating boundary conditions diminishes and the displacements predicted by numerical calculations converge to the analytical solutions.  相似文献