1,721,089 research outputs found
Lung cancer risk assessment at receptor site of a waste-to-energy plant
No full textThe toxicity of particulate matter emitted from waste-to-energy plants, is associated to the compounds attached to the particles, several of which have been classified by the International Agency for Research on Cancer (IARC) in the Group 1 carcinogens. In this paper a modified risk-assessment model, deriving from an existing one, was applied to estimate the lung cancer risk related to both ultrafine and coarse particles emitted from an incinerator whose people living nearby are exposed to. To this end, the measured values of Polycyclic Aromatic Hydrocarbons (PAHs), heavy metals (As, Cd, Ni) and PCDD/Fs (Polychlorinated dibenzodioxins/furans) emitted from an incinerator placed in Italy were used to calculate the Excess Lifetime Cancer Risk (ELCR) at the stack of the plant. The estimated ELCR was then used as input data in a numerical CFD (Computational Fluid Dynamics) model that solves the mass, momentum, turbulence and species transport equations to study the influence of wind speed and chimney height on the ELCR at receptor sites. Furthermore, combining meteorological data (wind speed and direction), and hypothesizing different exposure scenarios on the basis of time-activity patterns of people living nearby the plant, specific risk maps were obtained by evaluating ELCR around the incinerator. Results show that with the increasing of wind speed, the ELCR value downwind at the plant decreases and its point of maximum risk becomes closer to the stack. On the other hand, increasing the stack height decreases the ELCR, moving away from the stack the point of maximum risk. Finally, the risk maps for people living or working nearby the plant have highlighted that the excess risk of lung cancer due to the presence of the incinerator is below the WHO target (1 × 10−5)
Smokers’ lung cancer risk related to the cigarette-generated mainstream particles
No full textHighlights\ud
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• Application of a lung cancer risk model to smokers considering ultrafine particles\ud
• Measurement of particle concentrations in cigarette-generated mainstream aerosol\ud
• Excess life cancer risk for Italian smokers equal 2–6×10<sup>−1</sup>\ud
• Main contribution to the ELCR due to tobacco-specific nitrosamines\ud
• Great contribution due to the ultrafine particles (i.e. surface area metrics)\ud
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Abstract\ud
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Cigarette smoking represents the main cause of lung cancer events. This is due to the carcinogenic compounds condensed onto particles generated during the combustion process and then inhaled through the mainstream side (i.e. the cigarette filter side) of the cigarette. The present paper applied a novel lung cancer risk model, able to take into account both ultrafine and coarse particle toxicity, to the particle concentration levels measured in the mainstream aerosol of cigarettes in order to provide a useful provisional tool for testing different smoking scenarios.\ud
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To this end particle distributions and total concentrations in terms of number, surface area and mass aerosol metrics were measured at the mainstream side of five different cigarette brands using a condensation particle counter as well as mobility/aerodynamic particle sizers. On the basis of Italian smoking patterns and cigarette consumptions, the excess life cancer risk (ELCR) was then evaluated.\ud
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Particle concentrations equal to 3–6×10<sup>8</sup> part. cm<sup>−3</sup>, 60–120 mm<sup>2</sup> cm<sup>−3</sup>, and 5–9 g m<sup>−3</sup> for number, surface area and mass metrics, respectively, were measured. Most probable ELCR values ranged from 2×10<sup>−1</sup> to 6×10<sup>−1</sup> with the higher contribution due to the tobacco-specific nitrosamines and a minor (but still not negligible) contribution of B[a]p, Cd, and As.\ud
Keywords\ud
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excess lifetime cancer risk (ELCR); ultrafine particles; dose; cigarette; tobacco; SMPS; APS; lung cance
Misura e contabilizzazione dell’energia del gas naturale
No full textIl valore del gas naturale dipende strettamente dall’energia ad esso associata, ovvero dall’energia che potenzialmente è possibile ricavarne attraverso la sua combustione. Per questo motivo l’unica misura (diretta o indiretta) veramente rappresentativa del consumo di gas naturale è quella in energia.
Nel passato, i vincoli tecnologici rendevano tecnicamente realizzabile la sola misura dei volumi di gas nelle condizioni di esercizio (mediante semplici contatori volumetrici) in quanto, in analogia con le reti idriche, il gas di città distribuito era di fatto assimilato ad un fluido incomprimibile. Con lo sviluppo di metanodotti e della connessa distribuzione con reti in pressione la sola misura volumetrica non riusciva più a garantire la possibilità di una misura affidabile, specie nelle utenze di grandi dimensioni e ad elevate pressioni. Solo successivamente sono state sviluppate tecniche adeguate per la misura dei volumi e delle portate istantanee, di norma poi riportate alle condizioni di riferimento (attraverso dispositivi di correzione associati ai misuratori di flusso), per giungere poi alla misura (indiretta) dell’energia attraverso complesse catene di misura costituite da elementi primari, dispositivi di correzione e gascromatografi/analizzatori della qualità del gas. Questi ultimi strumenti, infatti, consentono un’affidabile misura dei principali parametri della qualità del gas o, più semplicemente, consentono di risalire al valore del potere calorifico del gas naturale vettoriato in rete.
Nonostante l’innovazione tecnologica faccia trasparire potenziali futuri sviluppi specie nel campo della miniaturizzazione dei sensori, nelle capacità trasmissive dei segnali di misura e nelle connesse elaborazioni, nella realtà operativa numerosi vincoli gestionali, economici e normativi rendono problematica la misura in energia anche in condizioni impiantistiche e climatiche non particolarmente critiche.
In questo lavoro gli autori, a valle di una breve descrizione delle tecniche di misura disponibili sul mercato nelle installazioni tipiche presenti sulle reti di trasporto, analizzano le principali criticità tecniche e normative connesse alla realizzazione della misura in energia del gas naturale nelle reti distributive nazionali
Influential parameters on ultrafine particle concentration downwind at waste-to-energy plants
No full textA numerical investigation on the parameters influencing the ultrafine particle concentrations downwind an incinerator plant has been carried out on a three-dimensional full scale model. The simulation was based on a modified version of the k-. Îμ turbulence model in order to take into account the thermal buoyancy effect of the plume, and reproducing a stable and neutral atmospheric boundary layer by setting appropriate values of velocity, turbulent kinetic energy and turbulent dissipation rate. The ability of the model to reproduce and maintain a stable atmospheric boundary layer was evaluated by analyzing the turbulent characteristics of the flow along the domain. A parametric analysis made on the basis of different plant operational, environmental, and flue gas treatment parameters was carried out in order to evaluate the impact of incinerator plants on the background concentration of ultrafine particles. The evaluation was made at 5. km downwind the chimney in a breathable area, showing that the most significant impact is due to the flue gas treatment section, with a variation on the background concentration up to 370% for a plant hypothetically working without controls on ultrafine particles emission. Operational and environmental parameters determine variations of the concentrations ranging from 1.62% to 4.48% for the lowest and highest chimney, from 1.41% to 4.52% for the lowest and highest wind speed and from 2.48% to 4.5% for the lowest and highest flue gas velocity, respectively. In addition, plume rise evaluation was carried out as a function of wind speed and flue gas velocity from the chimney
Confronto sperimentale dei sistemi di contabilizzazione del calore in un edificio residenziale
No full textPrimi risultati sperimentali di una campagna di misura atta a confrontare le prestazioni metrologiche dei sistemi di contabilizzazione del calore diretti e indiretti in edifici residenziali esistent
Development of a geographical information system (GIS) for the integration of solar energy in the energy planning of a wide area
Full text linkEnergy planning has become one of the most powerful tools for urban planning even if several constraints, (i.e., aesthetic, archaeological, landscape) and technological (low diffusion of Renewable Energy Sources, RES) reduce its spreading. An efficient and sustainable urban planning process should be based on detailed energy issues, such as: (i) the effective energetic characteristics and needs of the area like urban density and energy consumption, (ii) the integration of different RES and (iii) the diffusion of high efficiency technologies for energy production like cogeneration and district heating. The above-mentioned energetic issues and constraints must be constantly updated, in order to evaluate the consequences on environment and landscape due to new distributed generation technologies. Moreover, energy strategies and policies must be adapted to the actual evolution of the area. In this paper the authors present a Geographical Information Database System (GIS DB) based on: (i) the availability of land use (Land Capability Classification, LCC) to evaluate the productive potential; (ii) the estimation of residential energy consumptions (e.g., electricity), (iii) the integration of RES. The GIS DB model has been experimented in a wide area of Central Italy, considering exclusively the solar energy source for energy generation
Metrological analysis of smart heat meters
No full textNowadays heat meters only measure the consumptions of thermal energy and they normally do not allow remote transmission of measurement data for subsequent management purposes.
Furthermore, thermal energy measurements are normally performed without evaluating the real “quality” of the supplied thermal energy. On the other hand, the typical features of smart metering could allow to continuously transmit energy data, also interacting with supply and management issues.
In this paper, the authors present a brief critical analysis of the main issues of smart metering in thermal energy measurements both in a direct way using heat meters and in an indirect one using heat cost allocators to enhance energy savings of consumers.
The first results of some metrological tests aimed to evaluate the influence of common installation effects on commercial direct heat meters are also discussed
Unaccounted for gas in natural gas transport networks
No full textOne of the main issues in the natural gas (NG) transport networks management is represented by the Unaccounted for Gas (UAG). UAG is the quantity to be considered in the balance equation to take into account the unavoidable errors due to measurements and estimations. The resulting problem is twofold: on one hand fiscal and contractual, on the other hand the unavoidable pressure from the national authorities to reduce UAG.
In this paper the authors analyse the UAG trends in natural gas (NG) transport networks and present: i) an investigation about UAG in international networks; ii) a statistical analysis of annual and monthly trends for UAG; iii) the analysis of UAG causes
Analysis of the metrological performance of diaphragm gas meters in a city distribution network
No full textNowadays, in the italian distribution networks almost totally diaphragm gas meters are installed and it is quite usual to find very old meters still operating, because of the lack of a strict law regarding their legal duration until 2009, when finally a maximum legal duration of 15 years have been fixed [1].
The italian Authority for natural gas (AEEG) recently issued the mandatory resolution 155/08 [2] regarding the gradual substitution of all the old domestic gas meters installed in the italian distribution networks, in order to guarantee strict metrological performance for the consumers (also by correcting in the new models of gas meters the measured volumes with the operative gas temperature).
In such a wide market (only in Italy about 20 millions domestic gas meter are installed) the reduction of costs and the development of new components and materials in the gas meters are continously pursued both by meters manufacturers and gas city companies. Furthermore, the very old gas meters installed (before 1990) were manufactured with animal diaphragms, and it is common opinion that this can induce significant errors because of the decay of the performance of the diaphragm itself. In recent years (after 1990) the animal diaphragms have been replaced by synthetic ones, expected to be more resistant and reliable.
In this background, in order to better plan the substitution operations (involving about 350,000 gas meters only in Genoa up to 2016) in function of drift, age and installation of the meters and to properly define right customer policies, Genova Reti Gas commissioned to LAMI, the industrial measurement laboratory of the University of Cassino, and to Palmer, the Scientific Park of Southern Lazio, a detailed analysis of the gas meters installed in the gas city network of Genoa, by performing several performance tests [3, 4, 5, 6, 7].
Futhermore, the attention to unaccounted for gas (UAG) is nowadays continuously increasing both at transport and at distribution level and to this aim the knowledge of the metrological performance of the meters play a very critical role [8, 9
Small globes and pocket heat stress meters for WBGT and PHS evaluations. A critical analysis under controlled conditions
No full textThis paper is aimed at quantifying the effects of the well-known criticalities related to the use of small globes in the assessment of extreme hot thermal environments. Based on the experimental measurements carried out through a special apparatus able to reproduce a black enclosure under controlled conditions, the analysis has been focused on both screening (WBGT) and rational (PHS) assessment methods. Obtained results showed the underestimation of the WBGT values within 1 °C using small globes for measuring the WBGT index according to the Standard ISO 7243 and no relevant errors occur also in the presence of high radiative loads. These errors can be even eliminated if specific correction coefficients for the heat transfer by convection are used. On the other
hand, pocket WBGT meters based upon small globes and psychrometric (shielded) sensors – instead of the wet wick – are affected by an unacceptable underestimation (by more than 10 °C) of the WBGT that is particularly enhanced at low air velocity and high radiative loads. Finally, the systematic underestimation of the mean radiant temperature measured through small globes can lead the allowable exposure times predicted by the PHS model
to be underestimated by more than 5 h when a 38 mm table-tennis ball is used
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