Philosophiae Naturalis Principia Mathematica邦訳書の底本に関するノート

Routine navigational dredging generates huge quantities of marine sediment, posing significant environmental and economic burden. This research intended to explore the efficacy of wood waste biochar as a green admixture and assess the influence of different physico-chemical properties of dredged sediments on the mechanical performance of cement-based sediment products. X-ray diffraction and porosimetry analysis reflected that particle size distribution of sediments determined the pore structure formation and strength development. Thermal and calorimetry analyses showed that biochar incorporation slightly enhanced the cement hydration reaction, while its relatively large and brittle particles induced microcracks and weakened the strength of sediment products. Nevertheless, biochar addition enhanced immobilization of potentially toxic elements and organic contaminants, rendering the sediment products more environmentally acceptable. Hence, the innovative approach of this study can recycle dredged sediment and waste wood biochar to produce eco-friendly construction materials such as fill material and paving blocks.

The roles of biochar as green admixture for sediment-based construction products

Blended wind fields for wave modeling of tropical cyclones in the South China Sea and East China Sea

The addition of biochar as a sustainable strategy for the remediation of PAH-contaminated sediments.

Timely and effective remediation of contaminated sediments is essential for protecting human health and the environment and restoring beneficial uses to waterways. A number of site operational conditions influence the effect of environmental dredging of contaminated sediment on aquatic systems. Site experience shows that resuspension of contaminated sediment and release of contaminants occur during dredging and that contaminated sediment residuals will remain after operations. It is also understood that these processes affect the magnitude, distribution, and bioavailability of the contaminants, and hence the exposure and risk to receptors of concern. However, even after decades of sediment remediation project experience, substantial uncertainties still exist in our understanding of the cause-effect relationships relating dredging processes to risk. During the past few years, contaminated sediment site managers, researchers, and practitioners have recognized the need to better define and understand dredging-related processes. In this article, we present information and research needs on these processes as synthesized from recent symposia, reports, and remediation efforts. Although predictions about the effect of environmental dredging continue to improve, a clear need remains to better understand the effect that sediment remediation processes have on contaminant exposures and receptors of concern. Collecting, learning from, and incorporating new information into practice is the only avenue to improving the effectiveness of remedial operations.

Dredging processes and remedy effectiveness: relationship to the 4 Rs of environmental dredging. Integrated Environmental Assessment and Management, 6(4), 619-630

The evaluation of the coastal hazard and vulnerability caused by storm conditions is an important issue related to coastal flooding and erosion. Although these topics have been widely tackled by past research, they cannot be avoided, but need to be carefully managed by local authorities in order to limit damage to coastal infrastructure, to protect human life, habitats and sensitive species. Usually, this issue is tackled through common approaches at the regional scale. This paper illustrates the first steps of a research project aimed at assessing coastal hazard and vulnerability to wave-induced flooding at the national scale. In order to apply the method to the national scale, it is necessary to select a suitable dataset. This has to be consistent with the whole application area, concerning its spatial distribution, reliability and availability. Thus, one of the aims of this project is to perform a comparative analysis using data available at the national and local scale. The analysis was performed for the area of Montalto di Castro (Tyrrhenian Sea) by using datasets with different spatial resolutions. The results revealed that the use of low resolution data does not significantly affect the estimated nearshore wave features, while the wave runup in underestimated by about 25%. This underestimation influences also the vulnerability and hazard assessments. In particular, the vulnerability is conservatively assessed if low resolution data are used. On the other hand, the hazard is conservatively assessed when low resolution data are used only if the wave runup is amplified by considering the 25% underestimation. The results presented herein can be extended to other sites with the same general features (i.e., microtidal and dissipative coastal stretches).

https://www.mdpi.com/2077-1312/5/4/51/pdf

Comparative Analysis of Coastal Flooding Vulnerability and Hazard Assessment at National Scale

Semi-enclosed basins are often prone to storm surge events. Indeed, their meteorological exposition, the presence of large continental shelf and their shape can lead to strong sea level set-up. A real time system aimed at forecasting storm surge may be of great help to protect human activities (i.e. to forecast flooding due to storm surge events), to manage ports and to safeguard coasts safety. This paper aims at illustrating a simple method able to forecast storm surge events in semi-enclosed basins in real time. The method is based on a mixed approach in which the results obtained by means of a simplified physics based model with low computational costs are corrected by means of statistical techniques. The proposed method is applied to a point of interest located in the Northern part of the Adriatic Sea. The comparison of forecasted levels against observed values shows the satisfactory reliability of the forecasts.

Davide Pasquali

Papers

Comparative Analysis of Coastal Flooding Vulnerability and Hazard Assessment at National Scale

A simplified real time method to forecast semi-enclosed basins storm surge

The use of wave forecasts for maritime activities safety assessment

A simplified hindcast method for the estimation of extreme storm surge events in semi-enclosed basins

Effects of submerged berms on the stability of conventional rubble mound breakwaters