Advances in the fatigue assessment of wire ropes

This paper presents the findings from an in-depth analysis of the (axial) stiffness data recorded during tension–tension fatigue tests on wire ropes, particularly in relation to how changes in stiffness during testing relate to changes in rope strength. A linear relationship between stiffness and strength is shown to exist and a methodology presented for quantifying residual strength with applied cycles. New lower bound fatigue lines for six-strand rope and spiral strand are presented which are based on a 10% loss of strength. These new lines have the advantage of having been established using a common discard criterion for wire ropes.     

Combining pixel and object based image analysis of ultra-high resolution multibeam bathymetry and backscatter for habitat mapping in shallow marine waters

Habitat mapping data are increasingly being recognised for their importance in underpinning marine spatial planning. The ability to collect ultra-high resolution (cm) multibeam echosounder (MBES) data in shallow waters has facilitated understanding of the fine-scale distribution of benthic habitats in these areas that are often prone to human disturbance. Developing quantitative and objective approaches to integrate MBES data with ground observations for predictive modelling is essential for ensuring repeatability and providing confidence measures for habitat mapping products. Whilst supervised classification approaches are becoming more common, users are often faced with a decision whether to implement a pixel based (PB) or an object based (OB) image analysis approach, with often limited understanding of the potential influence of that decision on final map products and relative importance of data inputs to patterns observed. In this study, we apply an ensemble learning approach capable of integrating PB and OB Image Analysis from ultra-high resolution MBES bathymetry and backscatter data for mapping benthic habitats in Refuge Cove, a temperate coastal embayment in south-east Australia. We demonstrate the relative importance of PB and OB seafloor derivatives for the five broad benthic habitats that dominate the site. We found that OB and PB approaches performed well with differences in classification accuracy but not discernible statistically. However, a model incorporating elements of both approaches proved to be significantly more accurate than OB or PB methods alone and demonstrate the benefits of using MBES bathymetry and backscatter combined for class discrimination.     

Étude du mouvement du sol au voisinage d'une faille: II

Resumo Ni modifiis la hipotezojn de antaùa noto por reprezenti eventualajan zonojn kun plasteca fluo en la Tero. La simpla modelo uzita por la antaùsisma deformigo permesas studi la liniojn kie elementaj sirplanoj estas paralelaj al fiksa plandirekto. Oni trovas por la responda sisma deformigo simplan proksimuman formulon. Aplikado al la fendego de San Francisco donas profundecon de nur 7 km.

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Summary The hypotheses of a previous note are modified to take into account eventual zones of plastic flow in the ground. A simple model of preseismical strain is used, which enables us to study the repartition of the elementary shear planes. It is possible to deduce the extent of faulting in depth from the combined preseismical and seismical strains. An application to the San Francisco earthquake gives a depth of 7 km only.

     

Drop size dependent sulfate distribution in a growing cloud

A simple entraining air parcel model including cloud microphysical and chemical processes is used to calculate the distribution of sulfate over the drop sizes under continental background conditions. Under these conditions the aerosol sulfate is predicted to contribute the largest amount of aqueous sulfate in cloud drops. The sulfate produced by oxidation is found to contribute significantly in drops larger than 10 m radius.     

Elements of Water Balance and Hydrochemical Characteristic of Oligotrophic Bogs in the Southern Taiga Subzone of Western Siberia

The results of geochemical studies of water composition in an oligotrophic bog are analyzed. The specific features of the formation of the bog water composition in various phytocenoses are shown. The amounts of elements carried out with the runoff from the oligotrophic bog are assessed.     

A fuzzy-Markov-chain-based analysis method for reservoir operation

In this study, a fuzzy-Markov-chain-based stochastic dynamic programming (FM-SDP) method is developed for tackling uncertainties expressed as fuzzy sets and distributions with fuzzy probability (DFPs) in reservoir operation. The concept of DFPs used in Markov chain is presented as an extended form for expressing uncertainties including both stochastic and fuzzy characteristics. A fuzzy dominance index analysis approach is proposed for solving multiple fuzzy sets and DPFs in the proposed FM-SDP model. Solutions under a set of α-cut levels and fuzzy dominance indices can be generated by solving a series of deterministic submodels. The developed method is applied to a case study of a reservoir operation system. Solutions from FM-SDP provide a range of desired water-release policies under various system conditions for reservoir operation decision makers, reflecting dynamic and dual uncertain features of water availability simultaneously. The results indicate that the FM-SDP method could be applicable to practical problems for decision makers to obtain insight regarding the tradeoffs between economic and system reliability criteria. Willingness to obtain a lower benefit may guarantee meeting system-constraint demands; conversely, a desire to acquire a higher benefit could run into a higher risk of violating system constraints.     

Wind-driven upwelling and surface chlorophyll blooms in Greater Cook Strait

We present the results of a combined observational and numerical study to investigate cool plumes of nutrient-rich upwelled water that emanate near the Kahurangi Shoals and extend into Greater Cook Strait. Surface temperature and chlorophyll are mapped using satellite observations to produce surface climatologies, to validate a numerical simulation and to show the utility of using spatial temperature differences as a measure of upwelling. We find upwelling near the Kahurangi Shoals is strongly wind-driven in the weather band. Upwelling occurs at all times of the year, but its surface signature is only visible in summer months. The upwelled nutrient-rich water supports increased primary production compared to surrounding waters, particularly in summer when the water column is more stratified and surrounding surface waters are presumably nutrient depleted.     

Implications of pre-mesozoic orogeny in the geological evolution of the Himalaya and Indo-Gangetic Plains

An integrated geological analysis of the Himalaya and Indo-Gangetic Plains demonstrates that the Great Vindhyan Basin incorporating large parts of these morphotectonic units were uplifted into an uneven landmass due to the Pre-Mesozoic orogenic cycle. This uneven landmass was eroded off largely during a considerable part of the Devonian and Carboniferous thereby causing partial absence of sedimentary sequences of these periods except in parts of the Tethys Himalaya. The Late Paleozoic epeirogenic movements brought about renewed sedimentation in the Lesser and Tethys Himalayas in the Krol and Tethys Basins, respectively, which was terminated by the Himalayan Orogeny during Late Cretaceous—Early Eocene.     

Interevent Time Distribution in Seismicity: A Theoretical Approach

This paper presents an analysis of the distribution of the time τ between two consecutive events in a stationary point process. The study is motivated by the discovery of unified scaling laws for τ for the case of seismic events. We demonstrate that these laws cannot exist simultaneously in a seismogenic area. Under very natural assumptions we show that if, after rescaling to ensure Eτ =1, the interevent time has a universal distribution F, then F must be exponential. In other words, Corral’s unified scaling law cannot exist in the whole range of time. In the framework of a general cluster model we discuss the parameterization of an empirical unified law and the physical meaning of the parameters involved. An erratum to this article is available at .