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Page 202 of 977 Results 2011 - 2020 of 9762

Agnese Pini, Paolo Tomassetti, Marco Matiddi, Giuseppe Andrea de Lucia, Paolo Bello, Simone Zazzini, Giovanni Leuzzi, Paolo Monti
Microplastic detection and Lagrangian modelling in the Tyrrhenian Sea

In recent years the presence of microplastic (MP) in oceans is getting more and more attention due to its impacts on these environments. A major concern is represented by closed and densely populated basins, like the Mediterranean Sea. In this work, an assessment of MP concentrations in the Tyrrhenian Sea, a sub-basin of the Mediterranean Sea, is performed by means of numerical simulations. A Lagrangian stochastic model of dispersion, which requires hydrodynamic fields and MP sources as inputs, is employed. The hydrodynamic fields are supplied by the Copernicus Marine Environment Monitoring Service (CMEMS), while the MP sources are estimated by means of a novel method based on the population density. The results agree well with field data derived from Goletta Verde sampling campaign and highlight the importance of a correct estimation of the sources. Both the numerical results and field data show the presence of high polluted areas.

Bárbara Anes, Cristina Oliveira, Ricardo J. N. Bettencourt da Silva, M. Filomena Camoes
Characterization of Seawaters by Ion Chromatography – Comparison of ionic patterns and balances

Accurate characterization of seawater composition is required to understand chemical changes occurring in the ocean and their impact on marine ecosystems. In this work, three different seawater samples collected from the Portuguese Coast were analyzed by Ion Chromatography. For matrix comparison purposes, the same procedure was performed in two samples collected in two different locations in the Baltic Sea, known to be composed essentially by brackish water with a salinity gradient typical of estuaries. Special focus on calcium and magnesium ions is presented since both ions are essential for biological processes in the ocean s environment. The uncertainty associated with the results of ionic composition were evaluated to further use in the ionic balance and to assess the constancy of the proportion of major ionic components in the analysed seawaters. The collected information is of key usefulness for characterizing major components and for determining long-term trends or spatial variations of seawater composition.

Cezary Specht, Janusz Mindykowski, Pawel Dabrowski, Romuald Masnicki, Lukasz Marche, Mariusz Specht
Metrological aspects of the Tombolo effect investigation – Polish case study

Tombolo is a narrow belt connecting the mainland with an island lying near the shore formed as a result of sand and gravel being deposited by sea currents, which is most often created as a result of natural phenomena. However, it can also be caused by human activity, as is the case with the Sopot pier - a town located in the southern part of the Baltic Sea. As a result, the seabed constantly rises and the shoreline moves towards the sea. This paper deals with metrological aspects of the undertaken tombolo effect investigation, namely accuracy analysis of the measurement results. Aforementioned analysis concerns two methods used for creating a 3D beach model: firstly using images from unmanned aerial vehicles (UAV) and secondly, based on geodetic laser scanning (TLS – Trimble Laser Scanner).

Martina Zilioli, Alessandro Oggioni, Paolo Tagliolato, Cristiano Fugazza, Caterina Bergami, Alessandra Pugnetti, Paola Carrara
Making data management practices compliant with Essential Variables frameworks: A practical approach in the marine biological domain

Measuring marine biodiversity is essential to proper management of biological resources. Monitoring networks and observatory systems are adopting conceptual frameworks to agree on the fundamental variables describing the biodiversity change and to meaningfully inform policy makers. Biological and ecosystem Essential Ocean Variables (bio-eco EOVs) and Essential Biodiversity Variables (EBVs) both help to harmonize observations of different providers to essential measurements. Conceptual relationships between the two frameworks have been recently outlined to enrich data with complementary information. However, even if bio-eco EOVs and EBVs are adopted among research communities, they represent theoretical approaches whose implementations are often limited and still uncoupled. To evaluate operative reuse of biodiversity measurements, in this paper we identify differences and common aspects between the management recommendations established by the two frameworks in a synoptic comparison. Also, we provide evidences for applying the proposed approach to the marine component of the Long-Term Ecological Research (LTER) networks, by individuating in the Italian network (LTER-Italy) the Northern Adriatic Sea as a case study where compare, in further work, the data handling practices with the identified recommendations.

Fangxing Liu, Chengbin Liang, Qing He
Online Calibration for Smart Meters

Smart Meters have been deployed in different countries around the world during the past decade. Also, smart meter has been considered as the key element in the smart grid and substantial smart meter data analytics academic research have been conducted. A popular application for massive smart meter data analytics is monitoring smart meter running statues. Online calibration for is a novel method which compute meter errors through analysing meter data. This paper presents a comprehensive survey and basic model of smart meter online calibration. Meanwhile, we discuss low voltage electricity system model, data collection, novel learning algorithm issues and research trend of the remoting calibration method.

Houping Zhou, Qin Zhang, Zhiwen Tang
A Method of calibrating ATE while Test

A method of calibrating the integrated circuit ATE (Automatic Test Equipment) by synchronizing and measuring the signal on the DUT(Device Under Test) side while test is presented. This method connects the measuring instruments to the pin of the DUT while calibration. The computer controls the measuring instrument to capture the changes and values of the voltage and current on each pin of the DUT during the test. The specifications of the ATE can be calculated though the measured data.Therefore ,the ATE is calibrated via compare it’s primitive specifications and the measured one.

Yong Hu, Yulin Li, Qian Liu
Design of ATE Calibration Device Based on Microelectric Reference Materials

Microelectronic Reference materials (RMs) are a good way to achieve microelectronic traceability. To achieve full calibration of Automated Test Equipment(ATE), each test channel should be traced to calibration device of ATE based on RMs. This paper puts forward a design solution of calibration device of ATE based on RMs, which can realize the versatility and portability of calibration device, and realize automatic calibration progress.

Rui Xue, Xuewei Wang , Jing Wang, Lan Qiu, Bo Li, Min Cao
The Dynamic Error Analysis of the Current Transformer

In order to solve the problem of the dynamic error analysis of the current transformer, firstly, the mathematical model of the current transformer is established. Secondly, based on the working principle of the current transformer, the causes of the dynamic error of the current transformer are studied. On this basis, the important parameters affecting the dynamic error of the current transformer are analyzed theoretically. Thirdly, different dynamic test signals under complex working conditions are selected. After that, a composite error analysis algorithm is proposed to give the dynamic error quantitatively. Finally, the influence of the above parameters on the dynamic error is given, and the relationship between these parameters and the dynamic error is discussed. The results show that, according to the composite error analysis algorithm adopted in this paper, the dynamic error of different dynamic test signals under complex working conditions can be calculated effectively and the specific influence of each parameter on the dynamic error can be obtained.

Ling Zheng, Xuewei Wang, Jing Wang, Lan Qiu, Bo Li, Min Cao
A Method for Decomposing Dynamic Load Signals and Its Application

The current and power signals of high-power nonlinear dynamic load devices exhibit complex, random, fast-changing dynamic characteristics. These dynamic characteristics seriously affect the accurate measurement of smart electricity meters. Therefore, the research on the dynamic characteristic of high-power dynamic load has become an important issue to be solved in the field of error testing of smart electricity meters. Dynamic load signal decomposition is the basis and key issue for analyzing load dynamic characteristics. In this paper, the non-stationary stochastic process modulation model of dynamic load signal is established firstly. A method of least squares empirical mode power decomposition is studied, which divides the signal into quasi-steady-state terms and dynamic terms. Secondly, based on the proposed decomposition method, the actual collected signals of electrified railway traction substation are decomposed, which proves the effectiveness of the proposed model and the decomposition method. The theoretical method of this paper provides theoretical support for the dynamic error test of smart electricity meter.

Imrich Andráš, Ján Šaliga, Linus Michaeli
Compressed sensing with model based reconstruction

This work presents a way of reducing the power consumption of the existing wireless sensor network used for monitoring of water quality. The improvement of sensor nodes energy efficiency is achieved by utilizing compressed sensing and lowering the average sampling rate. A novel continuous model based reconstruction method is proposed, utilizing a water parameter signal model rather than a discrete dictionary. No trained dictionary and hence no signal database is required a priori to compressed sensing application.

Page 202 of 977 Results 2011 - 2020 of 9762