An Interpretation of ISO Guidelines for the Certification of Geological Reference Materials

Recommendations for the certification of reference materials, as published by the International Organisation for Standardisation (ISO), are reviewed and proposals made as to how they can be adapted for the certification of new geological reference materials. Whilst acknowledging the important contribution made by the large number of existing matrix-matched geological reference materials, it is recommended that future characterisation programmes should follow the ISO guidelines for certification, not the least so that laboratories can readily use the resultant samples to establish the traceability of geoanalytical results.     

Trend detection in river flow series: 1. Annual maximum flow / Détection de tendance dans des séries de débit fluvial: 1. Débit maximum annuel

Abstract

Results of a study on change detection in hydrological time series of annual maximum river flow are presented. Out of more than a thousand long time series made available by the Global Runoff Data Centre (GRDC) in Koblenz, Germany, a worldwide data set consisting of 195 long series of daily mean flow records was selected, based on such criteria as length of series, currency, lack of gaps and missing values, adequate geographical distribution, and priority to smaller catchments. The analysis of annual maximum flows does not support the hypothesis of ubiquitous growth of high flows. Although 27 cases of strong, statistically significant increase were identified by the Mann-Kendall test, there are 31 decreases as well, and most (137) time series do not show any significant changes (at the 10% level). Caution is advised in interpreting these results as flooding is a complex phenomenon, caused by a number of factors that can be associated with local, regional, and hemispheric climatic processes. Moreover, river flow has strong natural variability and exhibits long-term persistence which can confound the results of trend and significance tests.     

Calculation and analysis of negative skin of monopile applied for offshore wind turbine

Monopiles are considered to be as a kind of viable foundation types for offshore wind turbines. The effect of negative skin friction on pile foundation is always an important problem. There are very important theoretical and practical significance to study the distribution law of negative skin friction and the calculation method. Based on the special stratum, the stress and strain of the monopile and soil are simplified, and the improved Kezdi’s double-broken-line model is adopted. The analytical solution of negative skin friction of monopile is deduced according to the degree of skin friction. An engineering case was analyzed by the method, and the calculated results agree well with the measured data. The calculation method proposed can accurately describe the range of the monopile skin frictional distribution and the position of the neutral point, and it is simple and convenient to calculate, that is also a feasible method for calculating the negative skin friction of monopile of offshore wind turbines in practical engineering.     

Quantitative analysis for maritime delimitation: Reassessing the Bay of Bengal delimitation between Bangladesh and Myanmar

This article examines technical aspects of the maritime boundary dispute between Bangladesh and Myanmar (the ‘Bay of Bengal case’). This dispute was the first maritime delimitation determined by the International Tribunal for the Law of the Sea (ITLOS). The 2012 decision was also the first time that a maritime boundary for the seabed and subsoil of the Exclusive Economic Zone (EEZ) and the extended continental shelf (ECS) was determined by international adjudication. This was also therefore the first time that detailed technical quantification of seabed areas within the EEZ and ECS was needed for achieving an equitable division of these maritime zones in an international forum. Following review of the principles of maritime delimitation on which the ITLOS reached its determination, this article analyzes the legal status and delimitation effect of St. Martin's Island. Concerning the question of whether the legal regimes of the EEZ and continental shelf should be treated differently in a single delimitation line, although the ITLOS determined that the legal regimes should not be distinguished in the present case, a different approach is proposed for future cases. The article identifies how quantitative modelling can be used to achieve an equitable boundary and proposes a model to adjust provisional equidistance lines in accordance with the complex geophysical rules prescribed for the outer limits of the ECS in Article 76 of the United Nations Law of the Sea Convention (LOSC).     

Morphology and affiliation of the centric diatom Anaulus birostratus (Grunow) Grunow from South Africa

The morphology of a rectangular, pillow-shaped, centric diatom from the surf zone in False Bay and Algoa Bay was studied with the light microscope and by scanning and transmission electron microscopy. Acid-cleaned (i.e. free of organic material), and critical-point- and freeze-dried material was used. Certain important features were seen. There was a large variation in cell size and shape. Threads connecting the cells in chains, an external organic layer covering the cell, and chromatophore colour, number and shape are reported for the species, probably for the first time. Valve, girdle and areolar structure was studied in detail, and the notch seen with the light microscope in the middle part of the valve was identified with the electron microscope as a labiate process, the off-centre position of this process being distinctive of the species. The geographical distribution of the species, as described in available literature, is discussed.     

Implementation of Tidal Constituent Interpolation Method for the Israeli Coastline

Many ship-borne geodetic surveys at sea, such as Global Navigation Satellite System (GNSS)-based sea surface height (SSH) observation, acoustic profiling of the bottom, and others, deal with a dynamic topography which undergoes several changes during the survey campaign (e.g., changes in tide, salinity and currents). Those changes affect the measurements and may causes for some variations in the results. There are several methods for tidal variations correction, being the most dominant phenomena, such as tidal zoning, tidal constituent interpolation or ocean tidal models. In this study, we have implemented the tidal constituent interpolation method for the Israeli coastline in order to assess its quality and determine whether it is suitable for use in this particular region. This paper depicts the interpolation method, discusses some difficulties in the implementation for the Israeli coast and presents results from exemplary processing. In addition, we compare the results to those obtained using global and regional tidal models.     

Cement Deep Soil Mixing (CDSM) for Solidification of Soft Estuarine Sediments

A preliminary study was conducted to determine the potential for cement deep soil mixing (CDSM) technology as a method for in-situ solidification of contaminated river and estuarine sediments. The study was conducted in Newark Bay, near the mouth of the Passaic River, New Jersey. The primary objective of the study was to evaluate the viability of CDSM for the in-situ S/S with a focus on: 1) determining the correct mix of the cement slurry, which provides rapid stabilization of the sediment matrix, 2) potential resuspension of solids during CSDM operations, 3) the effects of high organic content on the solidification process, and 4) the feasibility of using conventional dredging/extraction methods once the sediments have been stabilized and allowed to cure. The results of the study show CDSM slurry mixtures, as low as 7% in cement content, result in significant solidification and strength gain of in-situ sediments under ambient conditions. In sediments with very high organic contents (> 20%), the slurry mix would need to be adjusted to account for retardation effects of organics on cement hydration. Sediment resuspension during application was shown to be minimal at a distance of as little as 75 feet from the mixing head. Strength gains were considerable, effectively consolidating the sediment particles in a secure matrix, but not so high as to preclude extraction of solidified sediments with conventional dredging equipment. Dredged solidified sediment exhibited characteristics of a stiff glacial clay, and as such was easier to handle and transport than untreated dredged sediments. This technique has high potential to be used as an interim remedial measure prior to either extraction and decontamination/disposal or proper capping.     

Abundance,distribution, and feeding patterns of juvenile coho salmon (Oncorhynchus kisutch) in the Juan de Fuca Eddy

The Juan de Fuca Eddy is a seasonal, counter-clockwise gyre off the mouth of the Strait of Juan de Fuca between Washington, USA and British Columbia, Canada that may provide favorable feeding habitat for juvenile coho salmon (Oncorhynchus kisutch) during their early marine existence. In late September 2002, physical and biological sampling was conducted along two transects of the eddy region. Surface rope trawling was conducted to capture juvenile salmon and other nekton, along with bongo and neuston net tows to examine potential mesozooplanktonic salmon prey. Presence of the Juan de Fuca Eddy was confirmed with vertical water profiles. In addition, nutrient and chlorophyll a concentrations collected from 3-m depth were within the range observed in previous studies within the eddy region. In the mesozooplankton community, euphausiids, chaetognaths, and decapod megalopae were common. In the diet of juvenile coho salmon, euphausiids and decapod megalopae were dominant by percent number, and larval and juvenile fish were dominant by percent weight. Feeding intensity (percent body weight) based on stomach contents was variable, but not significantly different among stations. To compare the Juan de Fuca Eddy region with an upwelling area, we sampled along a transect off La Push (LP), Washington, USA which is south of the eddy. The eddy region was found to be less productive than the LP transect. Nutrients were lower, chlorophyll a concentrations were higher, and zooplankton abundance was generally higher along the LP transect than in the eddy region. In addition, more juvenile coho salmon were captured from the LP transect than the eddy region. Prey items in stomachs of salmon from the LP transect were heterogeneous compared to those from the eddy region. Feeding intensity along the LP transect was slightly lower and more variable than in the eddy region, and differences in feeding intensity among LP stations were significant. In addition, feeding intensities among stations nested within regions were significantly different.     

Lateral dynamic response of a partially embedded pile subjected to combined loads in saturated soil

In this article, an analytical solution is proposed to investigate the lateral dynamic response of a pile which is partially embedded in saturated soil layer and subjected to combined lateral and vertical loads. The saturated soil is described by Biot’s poroelastic theory and the resistance of soil is derived by potential function method. The governing equation of the pile is solved by coupling soil resistance and continuity conditions between the pile and the soil. The dynamic impedances of the pile are then obtained through transfer matrix method. To verify the validity of the proposed procedure, the present solution is compared with available solution for an idealized case. Finally, a parametric study is performed to investigate the effects of various parameters on the stiffness and damping properties of the pile-soil system. It is found that permeability of the soil and vertical load has significant effects on the dynamic response of the pile.     

A review of the equations used to predict the velocity distribution within a ship’s propeller jet

Predicting the velocity within the ship’s propeller jet is the initial step to investigate the scouring made by the propeller jet. Albertson et al. (1950) suggested the investigation of a submerged jet can be undertaken through observation of the plain water jet from an orifice. The plain water jet investigation of Albertson et al. (1950) was based on the axial momentum theory. This has been the basis of all subsequent work with propeller jets. In reality, the velocity characteristic of a ship’s propeller jet is more complicated than a plain water jet. Fuehrer and Römisch (1977), Blaauw and van de Kaa (1978), Berger et al. (1981), Verhey (1983) and Hamill (1987) have carried out investigations using physical model. Current paper reviews the state-of-art of the equations used to predict the time-averaged axial, tangential and radial components of velocity within the zone of flow establishment and the zone of established flow of a ship’s propeller jet.