149 research outputs found

    Preliminary design of a hybrid electric powertrain for a earthmoving machine

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    The goal of this work is to evaluate the benefit of the hybridization of a Compact Wheel Loader (CWL) and to put into evidence the effect of the component size on its performance. To do this, a mathematical model has been developed using a backward approach, i.e. starting from the power request on a typical duty cycle made available by an industrial partner. The goals for the choice of the hybridization architecture were: minimizing fuel consumption, ensuring the simplicity of driveline and power management and ensuring compatibility with the vehicle structure.. A reduction up to 14% of fuel consumption was estimated in this investigation by combining engine downsizing with the usage of a Continuous Variable Transmission together with an optimization of the battery capacity and voltage

    Energy consumption and environmental impact of Urban Air mobility

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    Urban Air Mobility (UAM) is a recent concept proposed for solving urban mobility problems, such as urban traffic pollution, congestion, and noises. The goal of this investigation is to develop a backward model for an electric aerial taxi in order to estimate the electric consumption and the indirect emissions of carbon dioxide in a specified mission. The model takes as input the time histories of speed and altitude and estimates the power at the rotor shaft during the mission with a quasi-static approach. The shaft power is used as input for the electric drive where the motor is modelled with an efficiency map and a transfer function while an equivalent circuit model which includes aging effects is used for the battery. The emissions of CO 2 are calculated as a function of the Greenhouse emission intensity and compared with that of a hybrid electric taxi performing the same mission with the same payload. A plug-in Toyota Prius modelled through the software ADVISOR is considered for the comparison. The results show that the air taxi behaves better than the road taxi not only in terms of trip time but also from the environmental point of view if the charging of the battery is performed with the emission intensity factory expected to be reached in Europe in 2025

    Measurements of atmospheric aerosol in the Salentum Peninsula and its correlation with local meteorology

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    In this paper the results of measurements of Total Suspended Particles (TSP) and PM10 are presented. The samplings were carried out with a mobile laboratory in five locations on the Salentum peninsula situated in the southeastern part of Italy in Puglia. Measurements were taken discontinuously during the period 2002?2004. Some results of PM2.5 measurements taken only in 2004 are also presented. Up to now no systematic analyses of aerosol concentration in the Salentum peninsula have been presented in the scientific literature. This study is therefore a useful basis for assessing the local situation and for planning future monitoring and investigations. Measurements were performed using a standard European PM10 inlet (CEN?EN12341, 1998) and successive gravimetric detection of aerosol deposited over 24 hours periods on filters. The measurement sites can be considered representative of urban background for all the cases investigated. Results show concentrations in good agreement with lognormal distributions, indicating that the PM10 fraction is about 69% of TSP and PM2.5 is about 81% of PM10, which allows us to evaluate that the fraction of PM2.5 is about 56% of TSP. Concentration levels were correlated with local meteorological parameters, such as wind velocity, wind direction and precipitations. Results indicate that there is, on average, a substantial decrease of concentration levels in high wind conditions and on rainy days. They also suggest the possibility of a significant contribution 1 of African Dust to PM10 and TSP, especially in the summer season, which could be responsible for some periods of concentrations above the threshold imposed by the European legislation on PM10

    Measurements of atmospheric aerosol in the Salentum Peninsula and its correlation with local meteorology

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    In this paper the results of measurements of Total Suspended Particles (TSP), PM10 and PM2.5 and their correlation with meteorological parameters are presented. The samplings were carried out with a mobile laboratory in seven locations in the Salentum Peninsula located in the southeastern part of Italy in Puglia. Measurements were taken discontinuously during the period 2002-2005. Up to now no systematic analyses of aerosol concentrations in the Salentum Peninsula have been presented in the scientific literature. This study is therefore a useful basis for assessing the local situation and for planning future monitoring. Measurements have been performed, on a daily basis, using standard European inlet (CEN-EN12341, 1998) and successive gravimetric detection of aerosol deposited on filters. The measurement sites can be considered representative of urban background for all the cases investigated. An analysis of the random uncertainties (LOQ and LOD) for the different types of filters used is reported. Results show concentrations in good agreement with lognormal distributions, indicating that the PM10 fraction is about 66% of TSP and PM2.5 is about 67% of PM10, which allows us to evaluate that the fraction of PM2.5 is about 44% of TSP. Concentration levels were correlated with local meteorological parameters, especially with wind velocity and precipitations. Results indicate that during rainy days the average concentration is reduced of about 70% and the reduction is larger for TSP and PM10 with respect to PM2.5. There is, on average, a substantial decrease of concentration levels in high wind conditions. Results also suggest the possibility of a significant contribution of African dust to PM10 and TSP, especially in the spring and summer season, which could be responsible for some days with concentrations above the threshold imposed by the European legislation on PM10

    Optimal design of phononic media through genetic algorithm-informed pre-stress for the control of antiplane wave propagation

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    In this paper we employ genetic algorithms in order to theoretically design a range of phononic media that can act to prevent or ensure antiplane elastic wave propagation over a specific range of low frequencies, with each case corresponding to a specific pre-stress level. The medium described consists of an array of cylindrical annuli embedded inside an elastic matrix. The annuli are considered as capable of large strain and their constitutive response is described by the popular Mooney–Rivlin strain energy function. The simple nature of the medium described is an alternative approach to topology optimization in phononic media, which although useful, often gives rise to complex phase distributions inside a composite material, leading to more complicated manufacturing requirements

    Characterisation of PM2,5 concentrations and turbulent fluxes on a island of the Venice Lagoon using high temporal resolution measurements

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    This work presents an analysis of PM2.5 concentrations and vertical turbulent fluxes on an island of the Venice lagoon. Data were collected during three measurement campaigns in spring, summer and winter periods. Measurements were taken with a high-resolution optical PM2.5 detector, coupled with a micrometeorological station that allowed the evaluation of the vertical turbulent fluxes of PM2.5 using the eddy-correlation technique. The main objective of this paper is to analyse the daily and seasonal pattern in PM2.5 concentrations and fluxes and to discuss their correlation with the main meteorological and micrometeorological parameters using high temporal resolution measurements. Observed data showed a seasonal pattern in turbulent fluxes with daytime average positive value during winter and negative during summer. Deposition velocities, ranged from –60 to 20 mm/s, appeared to be mainly influenced by atmospheric stability. There were larger emissions in cases of high wind velocities blowing from water sector indicating a significant potential contribution of sea spray to PM2.5 fluxes. The local atmospheric circulation, due to the orography of the area, was characterised by diurnal winds coming from the Adriatic Sea and nocturnal wind coming from the Alps. This circulation influenced deposition velocity creating an increase of negative fluxes in the morning at the starting of the sea breeze. A diurnal pattern in concentration has been observed and it is similar for all three measurement campaigns, with higher concentrations in nocturnal periods. The daily pattern was investigated in terms of its correlation with meteorological and micro-meteorological parameters, and was found highly correlated with the diurnal pattern of boundary layer height (BLH) and with relative humidity

    Impact of maritime transport on particulate matter concentrations and chemical compositions in four port-cities of the Adriatic/Ionian area: an overview of the results of POSEIDON project

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    Pollutant emissions from ships and harbour activities constitute an important source of pollution of coastal areas with potential influences on the climate and the health of their inhabitants. A recent review (Viana et al., 2014) shows that these emissions could have an important impact on the Mediterranean and that there is a lack of data for the Eastern and South-Eastern part of this area. This work presents an analysis of the impact of ship emissions to atmospheric particle concentrations (PM) in four important port-cities (Patras Greece, Brindisi and Venice Italy, and Rijeka Croatia) of the Adriatic/Ionian area. The study was performed within the POSEIDON project (Pollution monitoring of ship emissions: an integrated approach for harbours of the Adriatic basin, funded within the MED Programme 2007-2013). The study uses an integrated approach using emission inventories, dispersion modelling and measurements taken at high temporal resolution (1 min) and low temporal resolution for chemical characterization of PM. The emission inventories of the four port-cities show that ships contribute between 11.7% and 31.0% of the total PM emissions being a source locally comparable with road traffic (ranging between 11.8% and 26.6%). The source apportionment using the receptor model PMF showed and oil combustion source (that includes ship emissions), characterized by V and Ni, in Brindisi, Venice and Rijeka with V/Ni ratio ranging between 1.4 and 4.2 indicating local differences in chemical profiles of the emissions. The V concentrations were used to evaluate the contributions of primary ship emissions to PM (Agrawal et al., 2009) that resulted between 1.3% and 2.8%. The contribution to secondary sulphate was 11% of PM2.5 in Brindisi (Cesari et al., 2014). The analysis of high-temporal resolution measurements taken near the harbour areas of Venice, Patras and Brindisi showed a contribution of ship emissions to PM2.5 varying between 3.5% and 7.4%. The relative contribution to particle number concentrations (PNC) was larger at all sites (between 6% and 26%). This demonstrates that ship particulate missions include mainly small and ultrafine particles. The trend of the impact of passenger ships primary emissions to PM2.5 concentrations in Venice between 2007 and 2012 showed a decrease from 7% (+-1%) to 3.5% (+-1%) even if the gross tonnage of ship traffic increased in the same period by 47% (Contini et al., 2015). This was a consequence of the use of low-sulphur content fuels due to the application of local mitigation strategies and of the European Directive 2005/33/EC. The WRF-CAMx modeling system was applied over the Central and Eastern Mediterranean so as to identify the air quality impact of ship emissions. The zero-out modelling method was implemented involving model simulations performed while including and omitting the ship emissions. The results for both gaseous and particulate pollutant concentrations generally show a fairly good agreement with observations at the areas under study. Agrawal et al., 2009. Environmental Science and Technology 43, 5398-5402. Cesari et al., 2014. Science of the Total Environment 497-498, 392-400. Contini et al., 2015. Atmospheric Environment 102, 183-190. Viana et al., 2014. Atmospheric Environment 90, 96-105

    Impact of maritime traffic on polycyclic aromatic hydrocarbons, metals and particulate matter in Venice air

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    Harbours are important hubs for economic growth in both tourism and commercial activities. They are also an environmental burden being a source of atmospheric pollution often localized near cities and industrial complexes. The aim of this study is to quantify the relative contribution of maritime traffic and harbour activities to atmospheric pollutant concentration in the Venice lagoon. The impact of ship traffic was quantified on various pollutants that are not directly included in the current European legislation for shipping emission reduction: (i) gaseous and particulate PAHs; (ii) metals in PM10; and (iii) PM10 and PM2.5. All contributions were correlated with the tonnage of ships during the sampling periods and results were used to evaluate the impact of the European Directive 2005/33/EC on air quality in Venice comparing measurements taken before and after the application of the Directive (year 2010). The outcomes suggest that legislation on ship traffic, which focused on the issue of the emissions of sulphur oxides, could be an efficient method also to reduce the impact of shipping on primary particulate matter concentration; on the other hand, we did not observe a significant reduction in the contribution of ship traffic and harbour activities to particulate PAHs and metals

    Overview of the Alaskan Layered Pollution and Chemical Analysis (ALPACA) Field Experiment

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    The Alaskan Layered Pollution And Chemical Analysis (ALPACA) field experiment was a collaborative study designed to improve understanding of pollution sources and chemical processes during winter (cold climate and low-photochemical activity), to investigate indoor pollution, and to study dispersion of pollution as affected by frequent temperature inversions. A number of the research goals were motivated by questions raised by residents of Fairbanks, Alaska, where the study was held. This paper describes the measurement strategies and the conditions encountered during the January and February 2022 field experiment, and reports early examples of how the measurements addressed research goals, particularly those of interest to the residents. Outdoor air measurements showed high concentrations of particulate matter and pollutant gases including volatile organic carbon species. During pollution events, low winds and extremely stable atmospheric conditions trapped pollution below 73 m, an extremely shallow vertical scale. Tethered-balloon-based measurements intercepted plumes aloft, which were associated with power plant point sources through transport modeling. Because cold climate residents spend much of their time indoors, the study included an indoor air quality component, where measurements were made inside and outside a house to study infiltration and indoor sources. In the absence of indoor activities such as cooking and/or heating with a pellet stove, indoor particulate matter concentrations were lower than outdoors; however, cooking and pellet stove burns often caused higher indoor particulate matter concentrations than outdoors. The mass-normalized particulate matter oxidative potential, a health-relevant property measured here by the reactivity with dithiothreiol, of indoor particles varied by source, with cooking particles having less oxidative potential per mass than pellet stove particles
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