The effectiveness of double hulls in reducing vessel-accident oil spillage     

Yip TL  Talley WK  Jin D 《Marine pollution bulletin》2011,62(11):2427-2432

While much work has been done in investigating determinants of oil spillage attributed to vessel accidents, little research has been conducted on the effectiveness of ship hull design in reducing marine pollution. This paper addresses whether the double-hull requirement reduces vessel-accident oil spillage. The volume of oil spillage due to oil-cargo vessel accidents was investigated using tobit regressions and an empirical data set of individual vessel accident pollution incidents investigated by the US Coast Guard from 2001 to 2008. The results indicate that the double hull design on average reduces the size of oil spills by 20% and 62% in tank barge and tanker ship accidents, respectively.  相似文献   

Impact of Hudson Bay on the energy balance in the Hudson Bay Lowlands and the potential for climatic modification     

Wayne R. Rouse  Richard L. Bello 《大气与海洋》2013,51(4):375-392

Abstract

Three sites were instrumented to measure all components of the energy balance. The sites were located in the Churchill, Manitoba region and comprised a Sea Site on a sand spit 1 km seaward from the mainland, a Nearcoast Site 2 km inland from the coast and an Inland Site 65 km inland. Measurements were made continuously over a 90‐day period from 19 May to 16 August 1984. This period encompassed the bulk of the growing season.

The measurements were stratified into onshore and offshore wind directions and were compared for 10‐day periods. The comparisons show very significant differences attributable to the cold summer conditions promoted by the sea ice in Hudson Bay. The ground heat flux and latent heat flux were much greater during offshore winds but the sensible heat flux was greatest for onshore winds. Air temperatures averaged 7°C warmer for offshore than for onshore winds. The reasons for these differences are detailed and the climatic modifications that would probably result from earlier sea‐ice melt are discussed. Some implications of climatic modification are also noted.  相似文献   

Chaos in turbulence driven by the magnetorotational instability     

Wayne F. Winters  Steven A. Balbus  John F. Hawley 《Monthly notices of the Royal Astronomical Society》2003,340(2):519-524

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Radio and visible-light observations of a coronal arcade transient     

T. E. Gergely  M. R. Kundu  F. T. Erskine III  C. Sawyer  W. J. Wagner  R. Illing  L. L. House  M. K. McCabe  R. T. Stewart  G. J. Nelson  M. J. Koomen  D. Michels  R. Howard  N. Sheeley 《Solar physics》1984,90(1):161-176

We discuss simultaneous visible-light and radio observations of a coronal transient that occurred on 9 April, 1980. Visible-light observations of the transient and the associated erupting prominence were available from the Coronagraph/Polarimeter carried aboard SMM, the P78-1 coronagraph, and from the Haleakala Observatory. Radio observations of the related type III-II-IV bursts were available from the Clark Lake and Culgoora Observatories. The transient was extremely complex; we suggest that an entire coronal arcade rather than just a single loop participated in the event. Type III burst sources observed at the beginning of the event were located along a nearby streamer, which was not disrupted, but was displaced by the outmoving loops. The type II burst showed large tangential motion, but unlike such sources usually do, it had no related herringbone structure. A moving type IV burst source can be associated with the most dense feature of the white-light transient.  相似文献   

IGCP 450/502 Field Workshop——-a 5054-km field geology experience     

Fred Kamona Gregor Borg Wayne Goodfellow 《《幕》》2006,29(3):213-215

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Bolide Energy Estimates from Infrasonic Measurements     

Wayne N. Edwards  Peter G. Brown  Douglas O. Revelle 《Earth, Moon, and Planets》2004,95(1-4):501-512

The acoustic amplitude-yield relationships, including formal errors, for a population of energetic (>0.05 kt) and well-observed bolide events have been investigated. Using various infrasonic signal measurements as a function of range, these data have been calibrated against optical yield estimates from satellite measurements. Correction for the presence of stratospheric winds has also been applied to the observations and is found to be small, suggesting that either scatter is dominated by other variations amongst the fireball population such as differing burst altitudes and greater or lesser amounts of fragmentation or the magnitude of the variability in the stratospheric winds, which can be comparable to or even exceed the strength of the winds themselves. Comparison to similar point source, ground-level nuclear and high explosive airwave data shows that bolide infrasound is consistently lower in amplitude. This downward shift relative to nuclear and HE data is interpreted as due in part to increased weak non-linearity during signal propagation from higher altitudes. This is a likely explanation, since mean estimates of the altitude of maximum ene0rgy deposition along the bolide trajectory was found to be between 20 and 30 km altitude for this fireball population.  相似文献   

Interactive effects of hypobaria, low temperature, and CO₂ atmospheres inhibit the growth of mesophilic Bacillus spp. under simulated martian conditions     

Andrew C. Schuerger  Wayne L. Nicholson 《Icarus》2006,185(1):143-152

Robotic spacecraft are launched with finite levels of terrestrial microorganisms that are similar to the microbial communities within facilities in which spacecraft are assembled. In particular, spores of mesophilic aerobic Bacillus species are common spacecraft contaminants considered most likely to survive interplanetary transfer to Mars. During the cruise phase to Mars, and then again during surface operations, microbial bioloads are exposed to a diversity of biocidal factors that are likely to render the microbial species either dead or significantly inhibited from active metabolic activity and replication. We report here, for the first time, that interactive effects of low pressure, low temperature, and high CO₂ atmospheres approaching conditions likely to be encountered on the martian surface strongly inhibit the growth and replication of seven common Bacillus spp. isolated from spacecraft. Tests were conducted within a small glass bell-jar system maintained in a low-temperature microbial incubator. Atmospheric pressures were controlled at 1013 (Earth-normal), 100, 50, 35, 25, or 15 mb, and temperatures were maintained at 30, 20, 15, 10, or 5 °C. Experiments were carried out for 48 h or 7 days under either Earth-normal O₂/N₂ or pure CO₂ atmospheres. Results indicated that low pressure, low temperature, and high CO₂ atmospheres, applied separately or in combination, were capable of inhibiting the growth and replication of B. pumilus SAFR-032, B. pumilus FO-36B, B. subtilis HA-101, B. subtilis 42HS-1, B. megaterium KL-197, B. licheniformis KL-196, and B. nealsonii FO-092 under simulated martian conditions. Endospores of all seven Bacillus spp. strains failed to germinate and grow at 25 mb at 30 °C. Although, vegetative cells of these strains exhibited a slightly greater ability to replicate at lower pressures than did endospores, vegetative cells of these species failed to grow at pressures below 25 mb. Interactive effects of these environmental parameters acted to generally increase the inhibitory nature of the low-pressure conditions on growth and replication of the seven Bacillus spp. tested.  相似文献   

Protoplanetary core formation by rain-out of iron drops     

Wayne L. Slattery 《Earth, Moon, and Planets》1978,19(4):443-456

Using the stochastic collection equation we find that the time scale for rain out of liquid iron in a Saturn mass protoplanet is rapid compared with other evolutionary time scales and hence iron protoplanetary core formation is inevitable. The survival of this core during subsequent protoplanetary evolution and the consequences of the rain-out on the evolution are also discussed.  相似文献   

Effect of particle characteristics on the evolution of particle size,particle morphology,and fabric of sands loaded under uniaxial compression     

Ganju  Eshan  Kılıç  Mustafa  Prezzi  Monica  Salgado  Rodrigo  Parab  Niranjan  Chen  Wayne 《Acta Geotechnica》2021,16(11):3489-3516

Acta Geotechnica - This paper presents the results and analyses of uniaxial compression experiments performed on three silica sands. The sands have comparable particle-size distributions, but their...  相似文献   

Two-dimensional finite-difference model of seafloor compliance     

Pavel Iassonov  Wayne Crawford 《Geophysical Journal International》2008,174(2):525-541

Seafloor compliance is the measure of seafloor deformation under a pressure signal. Our new 2-D finite-difference compliance modelling algorithm presents several advantages over the existing compliance models, including the ability to handle any gridded subsurface structure with no limitations on the gradients of the material properties, as well as significantly improved performance. Applying this method to some of the problems inaccessible to previously existing methods, demonstrates that lateral variations in subsurface structure must be accounted for to adequately interpret compliance data. In areas with significant lateral variations, the utilization of 1-D modelling and inversion is likely to result in high interpretation errors, even when additional subsurface structure information is available. We find that flattened pure melt bodies have a significantly higher compliance than cylindrical melt bodies with the same cross-sectional area. The compliance created by such bodies often has side peaks over their edges, which are as strong as or stronger than the central peak, requiring a series of measurements to best constrain their size and shear velocity. Finally, we find that the compliance data are far and away most sensitive to the broad, thick, lower-crustal partial melt zone. Our simple data fitting model for the compliance measurements on the East Pacific Rise at 9°48'N required shear velocities as low as 700 m s⁻¹ in the centre of this zone, far below the values previously estimated using 1-D model based inversions, suggesting higher melt percentages than those previously estimated, while small melt bodies in the upper part of the crust were found to have little or no effect on the measured compliance.  相似文献