Ultraviolet spectroscopic determination of the stability constants for copper carbonate and bicarbonate complexes up to the ionic strength of seawater

An ultraviolet spectroscopic study at 25°C is used to determine the stoichiometric stability constant of CuCO₃⁰ (β_CuCO3⁰) over a range of ionic strengths; extrapolation to zero ionic strength provides a thermodynamic constant (log β⁰_CuCO3⁰ = 6.89). At 0.69 m ionic strength, log β_CuCO3⁰) is 6.33.This study provides the first experimental evidence for the existence of CuHCO₃⁺. At 0.69 m ionic strength, log β_CuHCO3⁺ is 2.77.The ultraviolet molal absorptivity spectra for the two complexes are also determined. The spectrum for CuCO₃⁰ consists of a single band centered at 276.5 nm and was described well by a Gaussian function. The spectrum of CuHCO₃⁺ consists of at least two overlapping bands.Side reactions which might affect the data interpretation were included in the analysis of the results. The effects of the Cu(II) hydrolysis reactions were accounted for by using data from previous work, and possible effects due to copper-organic species were eliminated by a subtraction procedure.     

Numerical simulation of shear band formation in soils

Zones of localized shear strain, called bands, are initiated numerically within idealized cohesive and frictional soil specimens both by inhomogeneities and by imperfect boundaries. Qualitatively the results agree with experimental evidence, and give promise of quantitative analyses using better soil models, when the presence of porewater pressures will be of particular significance.     

Controlling incidental catch: An economic analysis of six management options

The authors identify a management approach to the problem of incidental catch and utilize that approach to evaluate six management options which are being considered to control incidental catch in the US fishery conservation zone of the Bering Sea. The evaluation is in terms of the ability of management to minimize the impact and control costs of incidental catch. The authors conclude that the use of economic disincentives tends to be preferable due to the inefficiencies and extensive information requirements of the alternative options.     

Towards a theory for type III solar radio bursts

The procedure developed in Smith (1974) to model the radiation source for type III bursts is modified to include scattering of radiation in the source itself. Since the inhomogeneities in the source must have the same statistical properties as the inhomogeneities used in tracing radiation from the source to the observer, these two parts of the type III problem are no longer uncoupled. Thus we use inhomogeneities consistent with the scattering inhomogeneities of Steinberg et al. (1971) and Riddle (1974) and apply the procedure to an archetype ‘fundamental-harmonic’ pair observed at Culgoora on 28 September, 1973 at 0319 UT. We find that it is impossible to model this burst with a source which is homogeneous in the sense that every part of the source has the same energy density in plasma waves. The density inhomogeneities in the source severely hamper amplification of the supposed fundamental. Possible ways out of this dilemma are discussed, including second harmonic pairs and a source with an inhomogeneous distribution of plasma waves. It is concluded that none of the possibilities are completely satisfactory to explain present observations and suggested that critical observations are missing.     

Beta-dispersion of low-frequency Rossby waves

An investigation is made into the dispersion of oceanic internal Rossby waves at annual and semi-annual frequencies. Turning of the group velocity vector due to latitudinal variations in the radius of deformation cannot be neglected, particularly in basins as large as the Pacific. This turning allows disturbances to propagate from high lattitudes into the equatorial zone and distorts the solutions in the western part of the basin. For no mean flow, and a coastline aligned north-south, an almost exact focus of wave energy is found very close to the equator at a distance of just under $\text{πc/4ω}$ from the eastern boundary, where $\text{c}$ is the eigenspeed of a high-frequency internal wave mode, and ω is the angular frequency of the low-frequency wave being studied. The focus depends on a long meridional wavelength excited at the coast, and a frequency small compared with $\text{c/a}$, where $\text{a}$ is the radius of the Earth. For the lowest baroclinic mode and waves of annual period, this distance is about 12 000 km. Equivalence of the ray theory and the theory of equatorial meridional modes is demonstrated for the simple cases where the latter applies.The effects of mean currents and irregular coastlines are examined. Barotropic mean currents may change the turning latitude and ray shapes, inducing critical layers and enhancing reflection. Baroclinic mean currents are seen to affect the rays by simply changing the speed in proportion to the depth of the thermocline. As long as the mean currents are geostrophically balanced, no “effective beta” term from variations in the thermocline depth appears, in contrast to the topographic Rossby wave problem.     

Copper concentrations in surface waters off the south-eastern atlantic coast,U.S.A.

Copper concentrations in surface waters off the southeastern United States coast range from 0.02 to 0.33 μg/kg (0.3–5.2 nmol/kg). Mean concentrations are lowest in Onslow Bay (0.07 μg/kg) and highest over the Blake Plateau (0.20 μg/kg). An explanation, compatible with the hydrography and hydrodynamics of the area, is proposed for the observed regional variations.     

On minimum spanning trees and the intergradation of clusters

Cluster analysis groups samples, but does not generally show gradations between clusters. To illustrate these relationships, principal-coordinate analysis and multidimensional scaling can be employed, but these methods may not be appropriate due to structural distortion. A minimum spanning tree (MST) computes a point-to-point path through the original matrix, and clusters are mapped on the MST diagram. The MST linkages, therefore, provide a natural continuum between the clusters, without distortion. Forty-six Silurian Tonoloway Limestone samples were analyzed for 16 sedimentary features indicative of subaerial exposure. Cluster analysis identified nine clusters which were reduced to five final, ordered groups by MST.