The volcano-magnetic effect     

Frank D. Stacey  Kenneth G. Barr  Geoffrey R. Robson 《Pure and Applied Geophysics》1965,62(1):96-104

Summary A geometrically simple volcano is considered, havig a spherical magma chamber of 2.5 km radius centred at 10 km depth. The Curie point isotherm is assumed to be a plane at 20 km depth, except for the spherical volume which is also non-magnetic. The stress pattern in the vicinity of the spherical chamber, due to regional stress of sufficient intensity to cause an eruptions, is used to calculate the change in magnetization which results from the piezomagnetic effect through the volume of solid rock. The consequent magnetic field anomaly at the surface is then obtaied by numerical integration of the dipole law of force over the stressed volume. For rocks of the type found on the volcanic island of St. Vincent (West Indies), this model gives a maximum local volcano-magnet c effect of about 7 gammas.  相似文献   

Control strategies for the Clam Wave Energy Device   总被引：1，自引：0，他引：1  

Martin Greenhow  Jay H. Rosen  Mark Reed 《Applied Ocean Research》1984,6(4):197-206

A promising wave energy device being currently investigated is the ‘clam’. The clam extracts energy by pumping air through a specially designed (Wells) turbine. Although operation of the Wells turbine does not require a rectified air flow, some additional control will be necessary to optimize the phase of the clam motion for good efficiencies. An examination of the equation of motion in the time domain suggests the possibility of phase control by mechanical, power take-off, or pneumatic latching. Latching can be shown to increase the efficiency of the device in the longer wavelengths of the wave spectrum, i.e. those of high incident wave power. Equivalently latching could be used to keep the device efficiency high while reducing its size, possibly resulting in cheaper power extraction.  相似文献   

Industrialised embayments and their environmental problems; a case study of Swansea Bay: Edited by M.B. COLLINS, F.T. BANNER, P.A. TYLER, S.J. WAKEFIELD and A.E. JAMES Pergamon Press (1980) $84.00 (£35.00) 632 pp., 266 illustrations     

Martin Angel 《Progress in Oceanography》1980,9(4):245-247

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Using the Mellor–Yamada mixing scheme in seasonally ice-covered seas—Corrigendum to: Parameterization of vertical mixing in the Weddell Sea [Ocean Modelling 6 (2004) 83–100]     

Ralph Timmermann  Martin Losch 《Ocean Modelling》2005,10(3-4):369-372

A coding error in the s-Coordinate Primitive Equation Model (SPEM) has led to misleading statements about the behaviour of the Mellor–Yamada level 2 parameterization of vertical mixing. It has been claimed that the scheme removes static instability only very slowly and preserves statically unstable stratifications for an unrealistic long time. This note corrects this statement by demonstrating that the Mellor–Yamada mixing scheme, if implemented correctly, tends to overestimate rather than underestimate vertical mixing in seasonally ice-covered seas. Similar to other mixing schemes with the same behaviour, this leads to spurious open ocean deep convection, an unrealistic homogenization of the water column, and a significant reduction of sea ice volume.  相似文献   

Cyclone and bioturbation effects on sediments from coral reef lagoons     

Martin J. Riddle 《Estuarine, Coastal and Shelf Science》1988,27(6)

Despite the severity of tropical cyclone ‘Winifred’, which crossed the Great Barrier Reef on 1 February 1986, there were little long-term effects on lagoon surface sediments from reefs in its path. Short-term effects were apparent only at one particularly exposed area. These were: an increase in proportion of the coarse fraction, the establishment of sand ripples, and the destruction of the mounds produced by callianassid shrimps (normally the dominant topographic feature). Within six weeks this area was indistinguishable from a typical reef lagoon. This is probably the result of sediment reworking by callianassid shrimp, involving selective burial of the coarse fragments and transport to the surface of finer particles. Sediment turnover rates by callianassids are commensurate with change to the sediment within the relatively short period observed. The sediment fauna responded quickly to the changes in sediment type. Immediately after the cyclone the disturbed area supported a fauna typical of the coarse sediments on the shallow reef flat, as the sediment reverted to a more normal type so the fauna changed back to that typical of a reef lagoon.  相似文献   

On the structural evolution of the Central Trough in the Norwegian and Danish sectors of the North Sea     

Martin B. Gowers  Asbjrn Sbe 《Marine and Petroleum Geology》1985,2(4):298-318

The Central Trough of the North Sea is not a simple rift graben. It is an elongated area of regional subsidence which was initiated in mid Cretaceous times and continued to subside through to the late Tertiary. Its form is not representative of pre-mid Cretaceous tectonics.In Late Permian times the North Sea was divided into a northern and southern Zechstein basin by the E-W trending Mid North Sea-Ringkøbing-Fyn High. The latter was dissected by a narrow graben trending NNW through the Tail End Graben and the Søgne Basin. The Feda Graben was a minor basin on the northern flank of the Mid North Sea High at this time. This structural configuration persisted until end Middle Jurassic times when a new WNW trend separated the Tail End Graben from the Søgne Basin. Right lateral wrench movement on this new trend caused excessive subsudence in the Tail End and Feda Grabens while the Søgne Basin became inactive.Upper Jurassic subsidence trends continued during the Early Cretaceous causing the deposition of large thicknesses of sediments in local areas along the trend. From mid Cretaceous times the regional subsidence of the Central Trough was dominant but significant structural inversions occurred in those areas of maximum Early Cretaceous and Late Jurassic subsidence.  相似文献   

Ten-year record of Thalassiosira nordenskioeldii population dynamics: comparison of aquaculture and non-aquaculture sites in the Quoddy Region     

Smith  Aaron C.; Martin  Jennifer L.; Ehrman  James M.; Kaczmarska  Irena 《ICES Journal of Marine Science》2001,58(2):391-397

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Understanding mackerel migration off Scotland: Tracking with echosounders and commercial data, and including environmental correlates and behaviour     

Walsh  Martin; Reid  David G.; Turrell  William R. 《ICES Journal of Marine Science》1995,52(6):925-939

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Properties of structure and function of cadmium-binding proteins/peptides from Euglena gracilis     

C Daniel Weber  Frank Shaw III  David H Petering 《Marine environmental research》1988,24(1-4)

Euglena gracilis makes two small Cd-binding proteins/peptides (Cd-BP I and Cd-BP II) in response to exposure to Cd²⁺. These proteins migrate slower than mammalian Cd-metallothionein (Cd-Mt) through Sephadex G-75, but like Cd-Mt also contain Zn and are separated into two species when chromatographed over a DEAE column. Both BPs are much less stable than Cd-Mt under acidic conditions. One source of this instability is that at least Cd-BP II contains acid-labile sulfide co-ordinated to the metals. It has been quantitated in Cd-BP II and shown to have a value of 1·25 ± 0·10 S²⁻/Cd. The reactivity of the Cd-binding sites in ligand substitution and thioldisulfide exchange reactions has been assessed. The reactions of Cd-BP I and II with pyridylazoresorcinol (PAR) were slow and displayed complex kinetic behavior. Similarly, both Cd-BPs react slowly and with complicated kinetics with 5,5′-dithiobis-(2-nitrobenzoate).  相似文献   

Direct determination of organic carbon in modern reef sediments and calcareous organisms after dissolution of carbonate     

Mark W. Sandstrom  Frank Tirendi  Alan Nott 《Marine Geology》1986,70(3-4):321-329

An improved method for the direct determination of organic carbon in calcareous marine sediments, organisms and particulate matter is described. Samples are dissolved in phosphoric acid to remove carbonates, purged with oxygen to remove CO₂, and the resulting acidic solution is analysed for total (dissolved and particulate) organic carbon. The method is rapid, involves minimal sample manipulation, and is both accurate (better than ± 2%) and precise (better than ± 0.2 mg organic carbon/g sediment). The method is especially suitable for modern carbonate sediments which have low levels of predominantly acid-soluble organic carbon.  相似文献