1,721,052 research outputs found
A Numerical Study of Effects of an Industrial Hazardous Release On People Egress
Full text linkThe release and dispersion of toxic materials from industrial equipment may pose severe concerns and have tragic consequences. The assessment of such scenarios relies on broad literature, approaches, and modelling tools that support estimating the impact area. However, hazard assessments do not generally embed the egress modelling and the impact of a toxic release on people evacuating. The present work couples a gas dispersion model with evacuation dynamics to estimate the near-field impact on people approaching a safe place. It is applied to a hypothetical case study concerning a release of dense chlorine, in which the effect of adopting different assumptions is discussed
A review of the basic safety requirements of emerging infrastructures for green transition
Full text linkThe transition to a Climate-Neutral economy requires a reduction of energy-related carbon dioxide emissions and Carbon dioxide capture and geological storage (CCS) is a key technology that will contribute to mitigating climate change. Hazards and risks related to processing, transport, and storage of CO2 are not new aspects, but peculiarities of CO2 safety scenarios can lead to risk underestimation and misperception. Solid-phase occurrence and heavy gas dispersion, multiphase releases, leakages from wells and storage sites, and the integrity of equipment subjected to internal corrosion and cryogenic temperatures, are typical scenarios involved in CCS chains. These are often mentioned in technical standards and regulations and require proper advanced assessment. In this work, the main hazards and risk scenarios in CCS operations with a special focus on atypical instances that are peculiar to the case of CO2 will be reviewed. Open issues concerning the modeling of consequences and specific risk-related topics are discussed
Atteggiamento di insegnanti e genitori verso l'integrazione scolastica di soggetti con ritardo mentale: Analisi delle variabili condizionanti
No full textAddressing waste disposal fires in open fields through large eddy simulations
No full textAddressing fires in waste disposal facilities is of topical interest for firefighting and environmental protection. Statistics of fires that involve fuel matrixes made of diversified wastes are escalating and ask for an effective response, both in prevention and mitigation. Crucial to this target is the consideration of underlying phenomena, and modeling of fire dynamics and pollutant emission also via robust numerical simulations. In this work, fires in waste disposal facilities are addressed with Large Eddy Simulation to test the capability to catch the main phenomena of the combustion of wastes made of plastic and the consequent emission of pollutants. This approach is applied to fuel matrixes in form of piles of different sizes, made of polyolefins and polyvinylchloride burned in an open field. The atmospheric dispersion of pollutants, including soot, carbon monoxide, carbon dioxide, and hydrogen chloride are investigated under different environmental conditions. Besides, thermal aspects are addressed to come up with indications of the heat release rate
Study of formation, sublimation and deposition of dry ice from carbon capture and storage pipelines
No full textClimate Change is caused by greenhouse gases such as CO2. Worldwide increases in energy demand coupled with a continued reliance on flues derived from fossil resources have contributed to a significant and severe increase in atmospheric levels of CO2. Scenarios for stabilizing the emissions of CO2 suggest its stabilization through a portfolio of mitigation actions including the deployment of Carbon Capture and Storage projects (CCS). One of the process step consists in the transportation of the CO2 to a storage location and this work focuses on dry ice formation following the accidental release of pressurized CO2 from CCS pipelines. The main aim is to investigate the dynamic and thermal fluid dynamic behaviour of a dry ice particle travelling down to the ground through air after the expansion to atmospheric conditions. This is achieved analyzing the influence of all the variables involved in the phenomenon, that is to say: particle initial diameter, post - expansion velocity and temperature, position and direction of the release point, air temperature, relative humidity and Pasquill atmospheric class of stability. The effect of these parameters on the in - flight life of the particle is discussed assembling an analytical model of equations of motion and of mass and heat transfer in order to establish which one is the most influential. © Copyright 2014, AIDIC Servizi S.r.l
Evaluation of Safety Scenarios for Fires in Waste Disposal Facilities through Numerical Simulations
Full text linkAfter several high-profile fires in waste and recycling facilities, the industry is put under pressure, especially as the materials processed in waste recycling are getting increasingly dangerous. Fire is an ever-present possibility at most waste management sites requiring proper preventive and mitigative strategies because it can cause significant damage to people, property and the environment. Fire risk assessment may benefit from applying the concept of fire safety engineering and numerical tools to approach the phenomena quantitatively. However, the complexity of such fire scenarios requires a detailed analysis that also involves an insight into fundamental processes, including pyrolysis of solid waste matrices and combustion of pyrolizate. These steps are critical for defining safety features of fire scenarios in waste disposal facilities, but the availability of input data may limit the modelling capability of numerical tools. The present work deals with modelling a fire scenario of a bale of plastics starting from literature data in which both pyrolysis and combustion are addressed. Having an accurate reaction model is of paramount importance in modelling solid waste fires. However, full-scale fire tests in open fields will be required to validate and systematize how piles of material burn dependently on boundary conditions
Hazard analysis of carbon sequestration pipelines. The effect of impurities and insulation specs on the release evolution
No full textGoing Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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