Guido Marseglia - Academia.edu (original) (raw)

Papers by Guido Marseglia

Research paper thumbnail of Mechanical Properties of Porous Structures for Dental Implants: Experimental Study and Computational Homogenization

Materials, 2021

A combined experimental and numerical study on titanium porous microstructures intended to interf... more A combined experimental and numerical study on titanium porous microstructures intended to interface the bone tissue and the solid homogeneous part of a modern dental implant is presented. A specific class of trabecular geometries is compared to a gyroid structure. Limitations associated with the application of the adopted selective laser melting technology to small microstructures with a pore size of 500 μm are first examined experimentally. The measured effective elastic properties of trabecular structures made of Ti6Al4V material support the computational framework based on homogenization with the difference between the measured and predicted Young’s moduli of the Dode Thick structure being less than 5%. In this regard, the extended finite element method is promoted, particularly in light of the complex sheet gyroid studied next. While for plastic material-based structures a close match between experiments and simulations was observed, an order of magnitude difference was encount...

Research paper thumbnail of The CRB multifuel biomass energy plant: description and preliminary modeling

Research paper thumbnail of Study about the link between injection strategy and knock onset in an optically accessible multi-cylinder GDI engine

Energy Conversion and Management

Abstract The effects of different injection strategies on the mixture formation and combustion pr... more Abstract The effects of different injection strategies on the mixture formation and combustion processes in a gasoline direct injection (GDI) engine are investigated. A synergic experimental and numerical analysis is realized on an optically accessible multi-cylinder engine under single and double injections, these last delivering the same amount of gasoline in two equal parts, the first during intake, the second during compression. In-cylinder pressure cycles and high temporal and spatial resolution combustion images are collected to highlight the possible occurrence of abnormal phenomena. AVL FIRE simulations are realized to characterize into detail the turbulent reacting flow and to evaluate the influence of mixture formation on flame propagation and the possible formation of zones in the end-gas region with conditions leading to self-ignition. Pollutants formation is also analysed. The flame propagation characteristics are indeed found different for the various injection strategies: for single injection, a faster spread occurs in the opposite side with respect to the injector position and towards the exhaust valves, while under split injection the flame front preferentially moves towards the intake valves. Computational fluid dynamics results give the relevant support to understand these peculiarities as related to in-cylinder equivalence ratio distribution and turbulent kinetic energy. In-chamber knock visualization is related to the numerical results of a simple self-ignition chemical model active in the end-gas zone, not yet reached by the main flame front. Split injection is shown to lead to advantages in terms of reduction of cyclic variability and tendency to knock, hence in increasing energy efficiency and in determining an overall reduction of undesired products of incomplete combustion.

Research paper thumbnail of An Experimental and Numerical Investigation of GDI Spray Impact over Walls at Different Temperatures

Research paper thumbnail of Experimental Techniques and Numerical Models to Detect Pollutant Emission in the Transport Sector

Urban Transport XXV, 2019

25th International Conference on Urban Transport and the Environment, Urban Transport 2019; Aveir... more 25th International Conference on Urban Transport and the Environment, Urban Transport 2019; Aveiro; Portugal; 25 June 2019 through 27 June 2019; Code 155807

Research paper thumbnail of Experimental and numerical investigation of the response of GLT beams exposed to fire

Construction and Building Materials, 2021

This paper presents a combined experimental and numerical investigation of the behavior of glued ... more This paper presents a combined experimental and numerical investigation of the behavior of glued laminated timber beams when exposed to fire. The influence on the time variation of charring rates based on the evolution of temperature profiles is examined for different fire scenarios and durations as well as different beam’s cross-section sizes. Predictions of charring depths provided by numerical simulations of heat transfer and simplified charring rate models are compared. In the absence of a mass transport representation, a Bayesian inference is introduced to identify the temperature-dependent material parameters for the conventional heat transfer model. A similar approach is adopted when adjusting the selected parameters of the charring rate models to account for variations in actual fire scenarios, which potentially depart from standard fire exposure. When compared to experimental results, both approaches confirmed their predictive capabilities, particularly in the stage of init...

Research paper thumbnail of Nanofluids Characterization for Spray Cooling Applications

In this paper the mathematical and physical correlation between fundamental thermophysical proper... more In this paper the mathematical and physical correlation between fundamental thermophysical properties of materials, with their structure, for nanofluid thermal performance in spray cooling applications is presented. The present work aims at clarifying the nanofluid characteristics, especially the geometry of their nanoparticles, leading to heat transfer enhancement at low particle concentration. The base fluid considered is distilled water with the surfactant cetyltrimethylammonium bromide (CTAB). Alumina and silver are used as nanoparticles. A systematic analysis addresses the effect of nanoparticles concentration and shape in spray hydrodynamics and heat transfer. Spray dynamics is mainly characterized using phase Doppler interferometry. Then, an extensive processing procedure is performed to thermal and spacetime symmetry images obtained with a high-speed thermographic camera to analyze the spray impact on a heated, smooth stainless-steel foil. There is some effect on the nanopar...

Research paper thumbnail of Recovery and Optimization of a Former Railway Transport Track

Urban Transport XXV

According to the new European standards on pollutant emissions and improving air quality levels, ... more According to the new European standards on pollutant emissions and improving air quality levels, the choice of low environmental impact systems of transport is fundamental. The requalification of disused railway transport today assumes an important role for the sustainability of the city and its building infrastructures. In particular, the reutilization of abandoned infrastructures, such as brownfield railways, allows the possibility of realizing travel systems with low pollutant concentrations. Railway rehabilitation designs respond to the actual requalification policies that are discouraging new exploitations, stopping degradation phenomenon and protecting incessancy of the environment, by means of not affecting the environment with new infrastructures. This paper presents the application of actual urban strategies, presenting a design proposal of requalification and optimization of the former railway transport track in Calabria, a region of southern Italy. Results show the possible solutions in terms of environmental and economic benefits obtained thanks to the use of an urban sustainable design. Moreover, social and tourist implications are highlighted.

Research paper thumbnail of Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

Sustainability

Heating wood to high temperature changes either temporarily or permanently its physical propertie... more Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual b...

Research paper thumbnail of Evaluation of Impact of Elevated Temperatures on Young’s Modulus of GLT Beams

Acta Polytechnica CTU Proceedings

The influence of elevated temperatures on mechanical behavior of glued laminated timber beams is ... more The influence of elevated temperatures on mechanical behavior of glued laminated timber beams is examined on the basis of tensile tests. Dog bone samples prepared from beams exposed to fire of variable duration were categorized with respect to the type and position of the failure crack, type and number of discontinuities such as knots, and the level of browning. The acquired experimental results suggest that the wood variability and the effect of growth discontinuities are probably more significant than the effect of elevated temperatures. To support this conclusion, further study is currently under way, exploring samples from the second series of the fire tests.

Research paper thumbnail of Thermofluid Characterization of Nanofluid Spray Cooling Combining Phase Doppler Interferometry with High-Speed Visualization and Time-Resolved IR Thermography

Energies

Spray impingement on smooth and heated surfaces is a highly complex thermofluid phenomenon presen... more Spray impingement on smooth and heated surfaces is a highly complex thermofluid phenomenon present in several engineering applications. The combination of phase Doppler interferometry, high-speed visualization, and time-resolved infrared thermography allows characterizing the heat transfer and fluid dynamics involved. Particular emphasis is given to the use of nanofluids in sprays due to their potential to enhance the heat transfer mechanisms. The results for low nanoparticle concentrations (up to 1 wt.%) show that the surfactant added to water, required to stabilize the nanofluids and minimize particle clustering, affects the spray’s main characteristics. Namely, the surfactant decreases the liquid surface tension leading to a larger wetted area and wettability, promoting heat transfer between the surface and the liquid film. However, since lower surface tension also tends to enhance splash near the edges of the wetted area, the gold nanospheres act to lessen such disturbances due ...

Research paper thumbnail of Investigation of CO2 Variation and Mapping Through Wearable Sensing Techniques for Measuring Pedestrians’ Exposure in Urban Areas

Sustainability

Citizens’ wellbeing is mainly threatened by poor air quality and local overheating due to human-a... more Citizens’ wellbeing is mainly threatened by poor air quality and local overheating due to human-activity concentration and land-cover/surface modification in urban areas. Peculiar morphology and metabolism of urban areas lead to the well-known urban-heat-island effect, characterized by higher air temperature in cities than in their surroundings. The environmental mapping of the urban outdoors at the pedestrian height could be a key tool to identify risky areas for humans in terms of both poor-air-quality exposure and thermal comfort. This study proposes urban environment investigation through a wearable miniaturized weather station to get the spatial distribution of key parameters according to the citizens’ perspective. The innovative system monitors and traces the field values of carbon dioxide (CO2) concentration, such as air temperature and wind-speed values, which have been demonstrated to be related to outdoor wellbeing. The presented monitoring campaign focused on a two-way, t...

Research paper thumbnail of Energy Efficiency in Gasoline Direct Injection Engines

Urban Transport XXIV, Sep 19, 2018

The growing awareness about the environmental impact of human activities and their influence on t... more The growing awareness about the environmental impact of human activities and their influence on the increased concentrations of greenhouse gases (GHGs) has recently affected research efforts in the transportation field. Knocking in gasoline direct ignition (GDI) engine, is a kind of abnormal combustion that can restrict engine energy efficiency. It can also lead to permanent engine damage, under specific operating conditions. This paper focuses on the state of the art of engine knock research, considering the causes, influencing aspects, effects and methodology to predict and to reduce the probability of occurrence of this phenomenon. We present some examples of experimental procedures that were followed to analyze this event, through visualization images that can be supported by numerical activity, consisting of fluid dynamic simulation of the combustion process. Different systems to measure engine knock intensity and some mathematical models to predict abnormal combustion, in order to improve engine performance, are analyzed. Finally, in this work we try to give new perspectives for future research, through the use of different techniques to achieve knocking reduction.

Research paper thumbnail of A simplified method for kinetic modeling of coffee silver skin pyrolysis by coupling pseudo-components peaks deconvolution analysis and model free- isoconversional methods

Biomass is a fundamental renewable resource to develop sustainable energy conversion systems with... more Biomass is a fundamental renewable resource to develop sustainable energy conversion systems with low environmental impact. The design of biomass pyrolysis, gasification, and combustion facilities requires a particular attention at kinetic aspects. A coffee production residue such as coffee silver skin, which is the main product of the coffee roasting industry, is very suitable for thermochemical conversion, being already dry and containing compounds like the ochratoxin which does not allow its use in the production of biochemicals. In this work, thermal degradation tests of coffee silver skin are made under inert conditions at various heating rates (5, 7, 10, 15°C/min) and a proper kinetic model was considered in order to quantify the activation energy (E α). The variation of E α with the conversion rate (α) was higher than 30%, showing that the process is kinetically complex and the kinetics cannot be described by a single-step model, according to the International Confederation o...

Research paper thumbnail of Optimization of downstream fuel logistics based on road infrastructure conditions and exposure to accident events

Transport Policy

Abstract The paper focuses on the fuel transport optimization network for the Total Erg Oil Compa... more Abstract The paper focuses on the fuel transport optimization network for the Total Erg Oil Company to the distribution points sited in a zone near Rome, in Italy. The numerical method is based on a capacitated vehicle itinerary issue for time intervals, considering various heuristic procedures. The fixed and time-dependent travel times are considered. Compared to the standard operational costs, a multivariable objective function is developed that considers: (1) the risk associated with an incidental event involving a fuel tank; (2) that not all the roads are suitable for heavy vehicles transporting fuel products. These two additional terms permit to better quantify the costs for the operator, since it is assumed that roads with higher number of accidents or with not suitable infrastructure conditions have also higher probability of making the fuel tank experiences at least a delay during the day. Results show that a proper vehicle routes design on our multivariable objective function allows economizing about 40 km daily respect to a benchmark. The fuel company can also consider the itinerary design, modifying the weights used with the aim to comprise the additional variables with respect to the standard operational costs, thus assuring a higher safety route planning.

Research paper thumbnail of Optimal Alignments for Designing Urban Transport Systems: Application to Seville

Sustainability

The achievement of some of the Sustainable Development Goals (SDGs) from the recent 2030 Agenda f... more The achievement of some of the Sustainable Development Goals (SDGs) from the recent 2030 Agenda for Sustainable Development has drawn the attention of many countries towards urban transport networks. Mathematical modeling constitutes an analytical tool for the formal description of a transportation system whereby it facilitates the introduction of variables and the definition of objectives to be optimized. One of the stages of the methodology followed in the design of urban transit systems starts with the determination of corridors to optimize the population covered by the system whilst taking into account the mobility patterns of potential users and the time saved when the public network is used instead of private means of transport. Since the capture of users occurs at stations, it seems reasonable to consider an extensive and homogeneous set of candidate sites evaluated according to the parameters considered (such as pedestrian population captured and destination preferences) and...

Research paper thumbnail of Pollutant emissions of a biomass gasifier inside a multifuel energy plant

Atmospheric Pollution Research

Abstract Several benefits in clean energy and pollutant emissions can be offered from biomass ene... more Abstract Several benefits in clean energy and pollutant emissions can be offered from biomass energy application. This research analyzes a biomass gasifier installed at the University of Perugia and presents the description of a multifuel biomass energy plant with all its components: the combustion chamber and the heat exchanger, installed to supply the thermal input to the turbine, with 100 kW electric power and 1 MW thermal power. The application of a Computational Fluid Dynamics (CFD) prediction model can help to better understand the knowledge on chemical and thermofluidodynamic features linked to pollutant emissions. A numerical modelling based on Ansys Fluent code is realized with the aim to reproduce the behaviour of the gasifier. Two different stoichiometric woodchips:air ratios are taken into account in the numerical calculations. Experimental tests have been conducted to validate the results of the numerical analysis. The obtained results show that the experimental and the numerical analysis with the 1:5 stoichiometric ratio are comparable. The influence of the woodchips:air stoichiometric ratio on the temperature distribution that may be reached inside the gasifier is highlighted. The relationship between woodchips:air stoichiometric ratio, temperature and NOx emissions is considered. Furthermore, a comparison between the values of NOx and CO pollutants obtained with the numerical model and experimental tests has been done. The gasification process contributes to the production of renewable energy and it can be combined with other energy cycles (e.g. Organic Rankine Cycle). The novelty of the work consists in the definition and validation of a method for the analysis of the operating temperatures of the gasifier to verify how they can be combined with other heat exchange systems and in the analysis of the pollutants during the gasification process.

Research paper thumbnail of Towards Zero Energy Stadiums: The Case Study of the Dacia Arena in Udine, Italy

Energies

The environmental impacts of sport events have been growing during the last decades, which has le... more The environmental impacts of sport events have been growing during the last decades, which has led to the organizing associations developing adequate countermeasures to both reduce carbon emissions due to construction and operational stages compensate for the emissions. This work aims at proposing an approach to stadiums energy enhancement that includes strategies largely recognized as effective and applicable to several building typologies (residential, commercial, academic, etc.). The selected case study is the Dacia Arena in northern Italy that has been recently refurbished and renovated. The proposed workflow has as a goal minimizing the increment of the operational emissions, caused by new heated areas in the stadium. Firstly, the energy consumption was estimated in dynamic state for Scenario 0 (current state) and Scenario 1 (refurbished state) to quantify the new plant’s energy demand. Secondly, two hypothetical system layouts were proposed and evaluated. In the first, the pow...

Research paper thumbnail of Experimental Tests and Modeling on a Combined Heat and Power Biomass Plant

Energies

Renewable energy sources can help the countries to achieve some of the Sustainable Development Go... more Renewable energy sources can help the countries to achieve some of the Sustainable Development Goals (SDGs) provided from the recent 2030 Agenda, allowing for clean, secure, reliable and affordable energy. Biomass technology is a relevant renewable energy to contribute to reach a clean and affordable energy production system with important emissions reduction of greenhouse gases (GHG). An innovative technological application of biomass energy consisting of a burner coupled with an external fired gas turbine (EFGT) has been developed for the production of electricity. This paper shows the results of the plant modelling by Aspen Plus environment and preliminary experimental tests; the validation of the proposed model allows for the main parameters to be defined that regulate the energy production plant supplied by woodchips.

Research paper thumbnail of The dynamic role of Italian energy strategies in the worldwide scenario

Kybernetes

Purpose The purpose of this paper is to set out ideas regarding a systematic approach that define... more Purpose The purpose of this paper is to set out ideas regarding a systematic approach that defines the Italian National energy strategies, considering the standards imposed from European Union. Design/methodology/approach A conceptual framework to estimate a model to define the energy policies for different sectors in the Italian case is underlined. The aims of Italian energy strategy in the worldwide scenario are discussed. The authors have considered the relations between the environment and the human impact on the energy conversion process by means of a conceptual method. Findings The actions considered to reach the aims of energy policies objectives are highlighted. This research aims to inform future development in the topic area, considering future perspectives and socio-economical implications for Italy. Originality/value The paper will be of interest to firm managers, ecologists and policymakers with a particular interest in energy policies, considering socio-technical impli...

Research paper thumbnail of Mechanical Properties of Porous Structures for Dental Implants: Experimental Study and Computational Homogenization

Materials, 2021

A combined experimental and numerical study on titanium porous microstructures intended to interf... more A combined experimental and numerical study on titanium porous microstructures intended to interface the bone tissue and the solid homogeneous part of a modern dental implant is presented. A specific class of trabecular geometries is compared to a gyroid structure. Limitations associated with the application of the adopted selective laser melting technology to small microstructures with a pore size of 500 μm are first examined experimentally. The measured effective elastic properties of trabecular structures made of Ti6Al4V material support the computational framework based on homogenization with the difference between the measured and predicted Young’s moduli of the Dode Thick structure being less than 5%. In this regard, the extended finite element method is promoted, particularly in light of the complex sheet gyroid studied next. While for plastic material-based structures a close match between experiments and simulations was observed, an order of magnitude difference was encount...

Research paper thumbnail of The CRB multifuel biomass energy plant: description and preliminary modeling

Research paper thumbnail of Study about the link between injection strategy and knock onset in an optically accessible multi-cylinder GDI engine

Energy Conversion and Management

Abstract The effects of different injection strategies on the mixture formation and combustion pr... more Abstract The effects of different injection strategies on the mixture formation and combustion processes in a gasoline direct injection (GDI) engine are investigated. A synergic experimental and numerical analysis is realized on an optically accessible multi-cylinder engine under single and double injections, these last delivering the same amount of gasoline in two equal parts, the first during intake, the second during compression. In-cylinder pressure cycles and high temporal and spatial resolution combustion images are collected to highlight the possible occurrence of abnormal phenomena. AVL FIRE simulations are realized to characterize into detail the turbulent reacting flow and to evaluate the influence of mixture formation on flame propagation and the possible formation of zones in the end-gas region with conditions leading to self-ignition. Pollutants formation is also analysed. The flame propagation characteristics are indeed found different for the various injection strategies: for single injection, a faster spread occurs in the opposite side with respect to the injector position and towards the exhaust valves, while under split injection the flame front preferentially moves towards the intake valves. Computational fluid dynamics results give the relevant support to understand these peculiarities as related to in-cylinder equivalence ratio distribution and turbulent kinetic energy. In-chamber knock visualization is related to the numerical results of a simple self-ignition chemical model active in the end-gas zone, not yet reached by the main flame front. Split injection is shown to lead to advantages in terms of reduction of cyclic variability and tendency to knock, hence in increasing energy efficiency and in determining an overall reduction of undesired products of incomplete combustion.

Research paper thumbnail of An Experimental and Numerical Investigation of GDI Spray Impact over Walls at Different Temperatures

Research paper thumbnail of Experimental Techniques and Numerical Models to Detect Pollutant Emission in the Transport Sector

Urban Transport XXV, 2019

25th International Conference on Urban Transport and the Environment, Urban Transport 2019; Aveir... more 25th International Conference on Urban Transport and the Environment, Urban Transport 2019; Aveiro; Portugal; 25 June 2019 through 27 June 2019; Code 155807

Research paper thumbnail of Experimental and numerical investigation of the response of GLT beams exposed to fire

Construction and Building Materials, 2021

This paper presents a combined experimental and numerical investigation of the behavior of glued ... more This paper presents a combined experimental and numerical investigation of the behavior of glued laminated timber beams when exposed to fire. The influence on the time variation of charring rates based on the evolution of temperature profiles is examined for different fire scenarios and durations as well as different beam’s cross-section sizes. Predictions of charring depths provided by numerical simulations of heat transfer and simplified charring rate models are compared. In the absence of a mass transport representation, a Bayesian inference is introduced to identify the temperature-dependent material parameters for the conventional heat transfer model. A similar approach is adopted when adjusting the selected parameters of the charring rate models to account for variations in actual fire scenarios, which potentially depart from standard fire exposure. When compared to experimental results, both approaches confirmed their predictive capabilities, particularly in the stage of init...

Research paper thumbnail of Nanofluids Characterization for Spray Cooling Applications

In this paper the mathematical and physical correlation between fundamental thermophysical proper... more In this paper the mathematical and physical correlation between fundamental thermophysical properties of materials, with their structure, for nanofluid thermal performance in spray cooling applications is presented. The present work aims at clarifying the nanofluid characteristics, especially the geometry of their nanoparticles, leading to heat transfer enhancement at low particle concentration. The base fluid considered is distilled water with the surfactant cetyltrimethylammonium bromide (CTAB). Alumina and silver are used as nanoparticles. A systematic analysis addresses the effect of nanoparticles concentration and shape in spray hydrodynamics and heat transfer. Spray dynamics is mainly characterized using phase Doppler interferometry. Then, an extensive processing procedure is performed to thermal and spacetime symmetry images obtained with a high-speed thermographic camera to analyze the spray impact on a heated, smooth stainless-steel foil. There is some effect on the nanopar...

Research paper thumbnail of Recovery and Optimization of a Former Railway Transport Track

Urban Transport XXV

According to the new European standards on pollutant emissions and improving air quality levels, ... more According to the new European standards on pollutant emissions and improving air quality levels, the choice of low environmental impact systems of transport is fundamental. The requalification of disused railway transport today assumes an important role for the sustainability of the city and its building infrastructures. In particular, the reutilization of abandoned infrastructures, such as brownfield railways, allows the possibility of realizing travel systems with low pollutant concentrations. Railway rehabilitation designs respond to the actual requalification policies that are discouraging new exploitations, stopping degradation phenomenon and protecting incessancy of the environment, by means of not affecting the environment with new infrastructures. This paper presents the application of actual urban strategies, presenting a design proposal of requalification and optimization of the former railway transport track in Calabria, a region of southern Italy. Results show the possible solutions in terms of environmental and economic benefits obtained thanks to the use of an urban sustainable design. Moreover, social and tourist implications are highlighted.

Research paper thumbnail of Mechanical Properties of Spruce Wood Extracted from GLT Beams Loaded by Fire

Sustainability

Heating wood to high temperature changes either temporarily or permanently its physical propertie... more Heating wood to high temperature changes either temporarily or permanently its physical properties. This issue is addressed in the present contribution by examining the effect of high temperature on residual mechanical properties of spruce wood, grounding on the results of full-scale fire tests performed on GLT beams. Given these tests, a computational model was developed to provide through-thickness temperature profiles allowing for the estimation of a charring depth on the one hand and on the other hand assigning a particular temperature to each specimen used subsequently in small-scale tensile tests. The measured Young’s moduli and tensile strengths were accompanied by the results from three-point bending test carried out on two groups of beams exposed to fire of a variable duration and differing in the width of the cross-section, b=100 mm (Group 1) and b=160 mm (Group 2). As expected, increasing the fire duration and reducing the initial beam cross-section reduces the residual b...

Research paper thumbnail of Evaluation of Impact of Elevated Temperatures on Young’s Modulus of GLT Beams

Acta Polytechnica CTU Proceedings

The influence of elevated temperatures on mechanical behavior of glued laminated timber beams is ... more The influence of elevated temperatures on mechanical behavior of glued laminated timber beams is examined on the basis of tensile tests. Dog bone samples prepared from beams exposed to fire of variable duration were categorized with respect to the type and position of the failure crack, type and number of discontinuities such as knots, and the level of browning. The acquired experimental results suggest that the wood variability and the effect of growth discontinuities are probably more significant than the effect of elevated temperatures. To support this conclusion, further study is currently under way, exploring samples from the second series of the fire tests.

Research paper thumbnail of Thermofluid Characterization of Nanofluid Spray Cooling Combining Phase Doppler Interferometry with High-Speed Visualization and Time-Resolved IR Thermography

Energies

Spray impingement on smooth and heated surfaces is a highly complex thermofluid phenomenon presen... more Spray impingement on smooth and heated surfaces is a highly complex thermofluid phenomenon present in several engineering applications. The combination of phase Doppler interferometry, high-speed visualization, and time-resolved infrared thermography allows characterizing the heat transfer and fluid dynamics involved. Particular emphasis is given to the use of nanofluids in sprays due to their potential to enhance the heat transfer mechanisms. The results for low nanoparticle concentrations (up to 1 wt.%) show that the surfactant added to water, required to stabilize the nanofluids and minimize particle clustering, affects the spray’s main characteristics. Namely, the surfactant decreases the liquid surface tension leading to a larger wetted area and wettability, promoting heat transfer between the surface and the liquid film. However, since lower surface tension also tends to enhance splash near the edges of the wetted area, the gold nanospheres act to lessen such disturbances due ...

Research paper thumbnail of Investigation of CO2 Variation and Mapping Through Wearable Sensing Techniques for Measuring Pedestrians’ Exposure in Urban Areas

Sustainability

Citizens’ wellbeing is mainly threatened by poor air quality and local overheating due to human-a... more Citizens’ wellbeing is mainly threatened by poor air quality and local overheating due to human-activity concentration and land-cover/surface modification in urban areas. Peculiar morphology and metabolism of urban areas lead to the well-known urban-heat-island effect, characterized by higher air temperature in cities than in their surroundings. The environmental mapping of the urban outdoors at the pedestrian height could be a key tool to identify risky areas for humans in terms of both poor-air-quality exposure and thermal comfort. This study proposes urban environment investigation through a wearable miniaturized weather station to get the spatial distribution of key parameters according to the citizens’ perspective. The innovative system monitors and traces the field values of carbon dioxide (CO2) concentration, such as air temperature and wind-speed values, which have been demonstrated to be related to outdoor wellbeing. The presented monitoring campaign focused on a two-way, t...

Research paper thumbnail of Energy Efficiency in Gasoline Direct Injection Engines

Urban Transport XXIV, Sep 19, 2018

The growing awareness about the environmental impact of human activities and their influence on t... more The growing awareness about the environmental impact of human activities and their influence on the increased concentrations of greenhouse gases (GHGs) has recently affected research efforts in the transportation field. Knocking in gasoline direct ignition (GDI) engine, is a kind of abnormal combustion that can restrict engine energy efficiency. It can also lead to permanent engine damage, under specific operating conditions. This paper focuses on the state of the art of engine knock research, considering the causes, influencing aspects, effects and methodology to predict and to reduce the probability of occurrence of this phenomenon. We present some examples of experimental procedures that were followed to analyze this event, through visualization images that can be supported by numerical activity, consisting of fluid dynamic simulation of the combustion process. Different systems to measure engine knock intensity and some mathematical models to predict abnormal combustion, in order to improve engine performance, are analyzed. Finally, in this work we try to give new perspectives for future research, through the use of different techniques to achieve knocking reduction.

Research paper thumbnail of A simplified method for kinetic modeling of coffee silver skin pyrolysis by coupling pseudo-components peaks deconvolution analysis and model free- isoconversional methods

Biomass is a fundamental renewable resource to develop sustainable energy conversion systems with... more Biomass is a fundamental renewable resource to develop sustainable energy conversion systems with low environmental impact. The design of biomass pyrolysis, gasification, and combustion facilities requires a particular attention at kinetic aspects. A coffee production residue such as coffee silver skin, which is the main product of the coffee roasting industry, is very suitable for thermochemical conversion, being already dry and containing compounds like the ochratoxin which does not allow its use in the production of biochemicals. In this work, thermal degradation tests of coffee silver skin are made under inert conditions at various heating rates (5, 7, 10, 15°C/min) and a proper kinetic model was considered in order to quantify the activation energy (E α). The variation of E α with the conversion rate (α) was higher than 30%, showing that the process is kinetically complex and the kinetics cannot be described by a single-step model, according to the International Confederation o...

Research paper thumbnail of Optimization of downstream fuel logistics based on road infrastructure conditions and exposure to accident events

Transport Policy

Abstract The paper focuses on the fuel transport optimization network for the Total Erg Oil Compa... more Abstract The paper focuses on the fuel transport optimization network for the Total Erg Oil Company to the distribution points sited in a zone near Rome, in Italy. The numerical method is based on a capacitated vehicle itinerary issue for time intervals, considering various heuristic procedures. The fixed and time-dependent travel times are considered. Compared to the standard operational costs, a multivariable objective function is developed that considers: (1) the risk associated with an incidental event involving a fuel tank; (2) that not all the roads are suitable for heavy vehicles transporting fuel products. These two additional terms permit to better quantify the costs for the operator, since it is assumed that roads with higher number of accidents or with not suitable infrastructure conditions have also higher probability of making the fuel tank experiences at least a delay during the day. Results show that a proper vehicle routes design on our multivariable objective function allows economizing about 40 km daily respect to a benchmark. The fuel company can also consider the itinerary design, modifying the weights used with the aim to comprise the additional variables with respect to the standard operational costs, thus assuring a higher safety route planning.

Research paper thumbnail of Optimal Alignments for Designing Urban Transport Systems: Application to Seville

Sustainability

The achievement of some of the Sustainable Development Goals (SDGs) from the recent 2030 Agenda f... more The achievement of some of the Sustainable Development Goals (SDGs) from the recent 2030 Agenda for Sustainable Development has drawn the attention of many countries towards urban transport networks. Mathematical modeling constitutes an analytical tool for the formal description of a transportation system whereby it facilitates the introduction of variables and the definition of objectives to be optimized. One of the stages of the methodology followed in the design of urban transit systems starts with the determination of corridors to optimize the population covered by the system whilst taking into account the mobility patterns of potential users and the time saved when the public network is used instead of private means of transport. Since the capture of users occurs at stations, it seems reasonable to consider an extensive and homogeneous set of candidate sites evaluated according to the parameters considered (such as pedestrian population captured and destination preferences) and...

Research paper thumbnail of Pollutant emissions of a biomass gasifier inside a multifuel energy plant

Atmospheric Pollution Research

Abstract Several benefits in clean energy and pollutant emissions can be offered from biomass ene... more Abstract Several benefits in clean energy and pollutant emissions can be offered from biomass energy application. This research analyzes a biomass gasifier installed at the University of Perugia and presents the description of a multifuel biomass energy plant with all its components: the combustion chamber and the heat exchanger, installed to supply the thermal input to the turbine, with 100 kW electric power and 1 MW thermal power. The application of a Computational Fluid Dynamics (CFD) prediction model can help to better understand the knowledge on chemical and thermofluidodynamic features linked to pollutant emissions. A numerical modelling based on Ansys Fluent code is realized with the aim to reproduce the behaviour of the gasifier. Two different stoichiometric woodchips:air ratios are taken into account in the numerical calculations. Experimental tests have been conducted to validate the results of the numerical analysis. The obtained results show that the experimental and the numerical analysis with the 1:5 stoichiometric ratio are comparable. The influence of the woodchips:air stoichiometric ratio on the temperature distribution that may be reached inside the gasifier is highlighted. The relationship between woodchips:air stoichiometric ratio, temperature and NOx emissions is considered. Furthermore, a comparison between the values of NOx and CO pollutants obtained with the numerical model and experimental tests has been done. The gasification process contributes to the production of renewable energy and it can be combined with other energy cycles (e.g. Organic Rankine Cycle). The novelty of the work consists in the definition and validation of a method for the analysis of the operating temperatures of the gasifier to verify how they can be combined with other heat exchange systems and in the analysis of the pollutants during the gasification process.

Research paper thumbnail of Towards Zero Energy Stadiums: The Case Study of the Dacia Arena in Udine, Italy

Energies

The environmental impacts of sport events have been growing during the last decades, which has le... more The environmental impacts of sport events have been growing during the last decades, which has led to the organizing associations developing adequate countermeasures to both reduce carbon emissions due to construction and operational stages compensate for the emissions. This work aims at proposing an approach to stadiums energy enhancement that includes strategies largely recognized as effective and applicable to several building typologies (residential, commercial, academic, etc.). The selected case study is the Dacia Arena in northern Italy that has been recently refurbished and renovated. The proposed workflow has as a goal minimizing the increment of the operational emissions, caused by new heated areas in the stadium. Firstly, the energy consumption was estimated in dynamic state for Scenario 0 (current state) and Scenario 1 (refurbished state) to quantify the new plant’s energy demand. Secondly, two hypothetical system layouts were proposed and evaluated. In the first, the pow...

Research paper thumbnail of Experimental Tests and Modeling on a Combined Heat and Power Biomass Plant

Energies

Renewable energy sources can help the countries to achieve some of the Sustainable Development Go... more Renewable energy sources can help the countries to achieve some of the Sustainable Development Goals (SDGs) provided from the recent 2030 Agenda, allowing for clean, secure, reliable and affordable energy. Biomass technology is a relevant renewable energy to contribute to reach a clean and affordable energy production system with important emissions reduction of greenhouse gases (GHG). An innovative technological application of biomass energy consisting of a burner coupled with an external fired gas turbine (EFGT) has been developed for the production of electricity. This paper shows the results of the plant modelling by Aspen Plus environment and preliminary experimental tests; the validation of the proposed model allows for the main parameters to be defined that regulate the energy production plant supplied by woodchips.

Research paper thumbnail of The dynamic role of Italian energy strategies in the worldwide scenario

Kybernetes

Purpose The purpose of this paper is to set out ideas regarding a systematic approach that define... more Purpose The purpose of this paper is to set out ideas regarding a systematic approach that defines the Italian National energy strategies, considering the standards imposed from European Union. Design/methodology/approach A conceptual framework to estimate a model to define the energy policies for different sectors in the Italian case is underlined. The aims of Italian energy strategy in the worldwide scenario are discussed. The authors have considered the relations between the environment and the human impact on the energy conversion process by means of a conceptual method. Findings The actions considered to reach the aims of energy policies objectives are highlighted. This research aims to inform future development in the topic area, considering future perspectives and socio-economical implications for Italy. Originality/value The paper will be of interest to firm managers, ecologists and policymakers with a particular interest in energy policies, considering socio-technical impli...