Search results for "Civil and Structural Engineering"
showing 10 items of 1404 documents
Multiple low-frequency broad band gaps generated by a phononic crystal of periodic circular cavity sandwich plates
2017
Abstract We propose a new type of phononic crystal (PnC) composed of a periodic alternation of circular cavity sandwich plates. In the low-frequency regime, the crystal can modulate the propagation of flexural waves. Governing equations are deduced basing on the classical theory of coupled extensional and flexural vibrations of plates. The dispersion relation of the infinite PnC is calculated by combining the transfer matrix method with Bloch theory. The dynamic response of the PnC with finite unit cells is further studied with finite element analysis. An experiment is carried out to demonstrate the performance of the PnC in vibration isolation. Numerical results and experimental results bo…
Choice of the detectors for light impurities plasma studies at W7-X using ‘CO Monitor’ system
2019
Abstarct The ‘CO Monitor’ is a new spectrometer system dedicated for the continuous measurements of line intensities of carbon, oxygen, boron and nitrogen at the fusion plasma experiment Wendelstein 7-X (W7-X). Its main purpose is to deliver constant information about indicated elements with high time resolution (better than 1 ms), but low spatial resolution since the line shapes are not going to be investigated. The system consists of four independent channels, each equipped with dispersive element dedicated for measurement of selected line of interest. In order to perform the highest efficiency of the ‘CO Monitor’ system, it is essential to choose the proper detector type for this task. T…
Guiding and splitting Lamb waves in coupled-resonator elastic waveguides
2018
Abstract We investigate experimentally Lamb wave propagation in coupled-resonator elastic waveguides (CREWs) formed by a chain of cavities in a two-dimensional phononic crystal slab with cross holes. Wide complete bandgaps, extending from 53 to 88 kHz, are first measured in a finite phononic crystal slab sample. A straight waveguide and a wave splitting circuit with 90° bends are then designed, fabricated and measured. Elastic Lamb waves are excited by a piezoelectric patch attached to one side of the phononic slab and detected using a scanning vibrometer. Strongly confined guiding and splitting at waveguide junctions are clearly observed for several guided waves. Numerical simulations are …
Discussion of "Analysis of extreme rainfall trends in sicily for the evaluation of depth-duration-frequency curves in climate change scenarios" by Lo…
2016
In the original paper, the Authors investigated the presence of trends in extreme rainfall depths of duration d = 1, 3, 6, 12 and 24 hours, in Sicily. Trend analysis was performed by using the Mann-Kendal non-parametric test, which was applied at-site, for a number of 65 raingauges well distributed in the region, for the period 1950-2008. In order to overcome the gap of missing data, six years moving average series were considered in the Author’s analysis. In this discussion, the discussers highlighted some important observations about the paper presented by the Authors: i) The Authors applied the non-parametric Mann Kendall test to moving average series of rainfall data. The use of moving …
Budyko’s Based Method for Annual Runoff Characterization across Different Climatic Areas: an Application to United States
2018
Runoff data knowledge is of fundamental importance for a wide range of hydrological, ecological, and socioeconomic applications. The reconstruction of annual runoff is a fundamental task for several activities related to water resources management, especially for ungauged basins. At catchment scales, the Budyko's framework provides an extremely useful and, in some cases, accurate estimation of the long-term partitioning of precipitation into evapotranspiration and runoff as a function of the prevailing climatic conditions. Recently the same long-term partitioning rules have been successfully used to describe water partitioning also at the annual scale and calculate the annual runoff distrib…
Influence of Wind on Suspended Matter in the Water of the Albufera of Valencia (Spain)
2021
Wind is one of the factors that has a great influence on suspended matter in lakes, especially in shallow lagoons. In order to know how wind affects the water in Albufera of Valencia, a shallow coastal lagoon, the measured variables of turbidity and transparency have been correlated with the estimates by processing Sentinel-2 satellite images with the Sen2Cor processor. Data from four years of study show that most of them are light to gentle easterly breezes and moderate to fresh westerly breezes. The results obtained show significant correlations between the measured variables and those obtained from the satellite images for total suspended matter and water transparency and with the averag…
Curve Numbers Seasonal Variation in Mid-Mediterranean Area
2018
AbstractThe curve number (CN) method is a popular technique for estimating a rainstorm event’s direct runoff (Q from its storm depth P). It relies on the parameter CN, a lumped expression of a wate...
Stage–Discharge Relationship for an Upstream Inclined Grid with Transversal Bars
2016
AbstractCheck dams with grids upgrading upstream are often used in mountain rivers, where intense sediment transport and steep slopes occur. In some cases, sloping grids are used in the construction of debris flow breakers. In this paper, the outflow process of an upstream-inclined grid with transversal bars is studied by using the dimensional analysis and the incomplete self-similarity theory. Next, the theoretical analysis shows that a power equation can be used for establishing the stage-discharge equation. The coefficient of the power equation depends on both the slope angle and the void ratio, whereas the exponent depends only on the slope angle. Finally, this deduced stage–discharge r…
Estimating Profit, Price, and Productivity Changes in Water Industry Using Bennet-Bowley Indicator
2019
AbstractThe assessment of profit, productivity, and price change over time is valuable for regulators and companies when setting tariffs. This paper innovates by comparing profit, price, and produc...
Phytoplankton distribution in Mar Menor coastal lagoon (SE Spain) during 2017.
2020
The Mar Menor is a Spanish coastal lagoon of great ecological and economic interest. The agricultural and tourist activities developed in the surroundings of the lagoon, together with the modifications in its channels of connection with the Mediterranean Sea, have notably affected the quality of its waters, which is altering the natural balance of the ecosystem. In this work, an analysis of the density of phytoplankton present in the lagoon between the months of May to December 2017 was carried out. The results indicate a significant increase in phytoplankton density between 2500 and 67,300 cells/mL compared to previous data of 1981 (between 10 and 500 cells/mL). Concentration of Chlorophyl…