Wave-in-deck loads on coastal bridges and the role of air

Recent failures of coastal bridges during extreme storm events have focused attention on the need for research on wave loading of coastal structures suspended above the still water level. This paper presents findings from large-scale experimental work carried out in the wave basin of the Yokohama Port and Airport Technical Investigation Office. Measurements from physical model tests are used to gain insights on the dynamics of wave-loading of coastal bridges and to derive an “ad-hoc” prediction method for both quasi-static and impulsive wave loads. The effect of openings in the bridge deck is also discussed, and guidance derived for design purpose.     

Producing an Indigenous Knowledge Web GIS for Arctic Alaska Communities: Challenges,Successes, and Lessons Learned

A traditional knowledge “Iñupiaq Web GIS”, based on a five‐year study and containing observations and environmental knowledge of Iñupiat communities indigenous to Arctic Alaska, was incorporated into a Web‐based platform. The website, “Arctic Cultural Cartography,” was created to be an open portal through which the password‐protected “Iñupiaq Web GIS” could be accessed. We discuss the process of developing the web GIS including the incorporation of user‐friendly features such as links to interactive maps, video clips of interviews, discussion boards, and the integration of popular web interfaces such as Facebook. We also discuss short‐ and long‐term goals for the further development of the GIS, its potential as a sustainable, participatory online database for sharing pertinent ecological knowledge, and challenges in achieving optimal community involvement given constraints imposed by remote locations with limited bandwidth.     

Geochemical characteristics of waters in mineralised area of Peloritani Mountains (Sicily,Italy)

This paper presents the results of a study on the geochemistry of waters circulating in the mineralised area of the south-eastern sector of Mt. Peloritani (north-eastern Sicily, Italy), aimed at basic understanding of the geochemical processes influencing their chemical composition. Chemico-physical parameters and data on 26 major and minor chemical elements are reported for 103 water samples. Water chemistry is mainly dominated by dissolution of carbonates and hydrolysis of aluminosilicate minerals. Total dissolved salts (TDS) range from 80 to 1398 mg/L. All the waters exhibit E_H characteristic of an oxygenated environment. Excluding two samples, which show very high H⁺ activity (pH = 3.0 and 2.7), all the waters have pH values in the range 6.2–8.6. Cluster analysis based on major ion contents defined three main chemical water types, reflecting different hydrochemical processes. The first, group I, has low salinity (average TDS = 118 ± 30 mg/L) and abundance orders (meq/L) Na > Ca ≈ Mg > K and Cl ≈ HCO₃ > SO₄. With increased water–rock interaction, waters in groups II and III become more saline, changing composition towards SO₄–Cl-alkaline earth and HCO₃-alkaline earth types. Weathering of carbonate minerals causes waters to become saturated with respect to calcite and dolomite, whereas the incongruent dissolution of aluminosilicate minerals causes the solution to reach equilibrium with kaolinite and to form smectites. Trace element geochemistry in the analysed waters reflects interactions between waters and existing mineralisation, with elemental concentrations showing highly variable values, and higher concentrations of As, Pb, Sb and Zn near known mineralisation. Lead–Zn and As–Sb statistical associations, probably distinguishing interactions with different mineralogical phase paragenesis, were revealed by factor analysis. The main aqueous chemical forms of trace elements predicted by chemical speciation calculations are also reported. As most of the analysed spring waters provide the main source of freshwater for domestic purposes, attention should be given to As and Sb, whose concentrations exceed the recommended limits.     

The impact of metals on the reproductive mechanisms of the ascidian Ciona intestinalis

Environmental pollution due to anthropogenic activities may exert an adverse impact on the reproductive mechanisms of animals. In particular, environmental chemicals introduced into seawater are able to disrupt the normal development and function of the reproductive system of marine animals. In this study, we have used the whole‐cell voltage clamp technique to examine the effects of four metals – lead, cadmium, mercury, and zinc – on reproductive mechanisms of the marine ascidian Ciona intestinalis (tunicates). In particular, we measured the effect of metals on plasma membrane electrical properties, the steady‐state conductance, the fertilization current in the mature oocyte, and larval development. Results show that oocyte voltage‐gated sodium currents are significantly reduced by all four metals, steady‐state conductance is affected only by zinc, and post‐fertilization contraction is inhibited only by lead. The fertilization current is suppressed in the presence of zinc and mercury. Embryo development up to larval stage is inhibited by zinc and mercury exposure with a reversible effect; however, a long‐term effect on larval morphology was observed. After exposure to cadmium, fertilization occurs but gives rise to abnormal larval development. These findings highlight the point that exposure to metals represents a significant risk factor for the physiology of reproduction of marine species and suggest a possible role of the C. intestinalis as a bioindicator for marine pollution monitoring.     

Dynamic response and sliding distance of composite breakwaters under breaking and non-breaking wave attack

Over the last 15 years improved awareness of wave impact induced failures has focused attention on the need to account for the dynamic response of maritime structures to wave impact load. In this work a non-linear model is introduced that allows evaluating the effective design load and the potential sliding of caisson breakwater subject to both pulsating and impulsive wave loads. The caisson dynamics is modelled using a time-step numerical method to solve numerically the equations of motion for a rigid body founded on multiple non-linear springs having both horizontal and vertical stiffness. The model is first shown to correctly describe the dynamics of caisson breakwaters subject to wave attack, including nonlinear features of wave–structure–soil interaction. Predictions of sliding distances by the new method are then compared with measurements from physical model tests, showing very good agreement with observations. The model succeeds in describing the physics that stands behind the process and is fast, accurate and flexible enough to be suitable for performance design of caisson breakwaters.     

Investigating the role of stratigraphy in large-area physically-based analysis of December 1999 Cervinara shallow landslides

The paper describes a large-area analysis of the triggering zones of shallow landslides on a case of unsaturated layered volcanic air-fall (pyroclastic) soil deposits in Cervinara site (18 km²), Southern Italy. The physically-based model TRIGRS (Transient Rainfall Infiltration-Based Grid Regional Slope-Stability) is used, which is used with either saturated or unsaturated conditions and implemented in a GIS platform. In addition to using the TRIGRS model to simulate some recent landslides, a new simplified approach is also tested to take into account the actual layered soil stratigraphy. The consistency check of the model and of the input data is performed with reference to slope stable conditions before rainfall. The performances of the models are evaluated through the ROC curves and two other quantitative indexes taken from the literature referring to the slope failures caused by December 1999 rainstorm. Notwithstanding the simplifications and limitations of the present work, both unsaturated conditions and layered stratigraphy are outlined as key factors for the slope stability of shallow deposits of unsaturated coarse-grained soils subjected to short heavy rainfall.     

Large-Eddy Simulations of Pollutant Removal Enhancement from Urban Canyons

Boundary-Layer Meteorology - Techniques for improving the removal of pollution from urban canyons are crucial for air quality control in cities. The removal mainly occurs at the building roof...     

A Method of Analysis for Turbulent Flows Using the Streamline Coordinate System

A procedure is described for analysing the transport equations for Reynolds stresses written in a streamline coordinate system, starting from the fields of first- and second-order moments of wind velocity measured in a terrain-following system over topography. In the analysis, the equations are split into two parts: the first contains the terms that can be calculated directly from measurements; the second contains third-order moments that are parameterized using suitable models. To evaluate the error associated with both parts, a Monte-Carlo technique that takes into account the experimental errors is proposed. An example of the application of this method for the Reynolds shear stress equation, using wind-tunnel data for non-separating flow over a two-dimensional valley, is reported. The comparison between the measured and modelled parts is fair near the surface, while at higher levels, the modelled part can be shown to miss a correct treatment of the third-order moments. In the frame of this analysis, the use of the correct derivative transformation has been found to be significant even for moderately sloping topography.