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The interest in hydrogen-based green energy is increasing worldwide, and the same is true for hydrogen-powered vehicles. Among the possible solutions to store hydrogen in such vehicles, cryogenic tanks equipped with multi-layer insulation (MLI) are the most promising to increase the amount of energy stored per unit volume. However, MLI is affected by severe deterioration when exposed to an external source of heat such as a fire following a car accident, leaving the tank unprotected and leading to failure in a relatively short time. In this work, a one-dimensional model to evaluate MLI thermal degradation when a liquid hydrogen tank is exposed to fire is presented. The relevance of taking MLI degradation into account when simulating the pressure increase due to external fire exposure is here demonstrated through the analysis of several case studies. The results show that MLI systems performance depletes within a few minutes of exposure to hydrocarbon poolfire.

Hydrogen is a promising zero-emission fuel that could play a key role in the transition towards a more sustainable economy. It is regarded as a possible fuel for the future that could replace traditional fossil fuels and reduce the consequent amount of greenhouse gas emissions. In contrast with the undeniable benefits introduced by the use of hydrogen as a fuel, its hazardous properties rise concern from the safety standpoint. A potential loss of integrity of the storage equipment might lead to severe consequences such as fires and explosions. The current investigation aims at quantifying the impact of the outcomes of an unexpected hydrogen release from the storage vessels designed for hydrogen-powered buses. A comparative analysis is carried out considering the different conditions in which hydrogen is currently stored on board: as a high-pressure gas, as a cryogenic liquid or as a cryo-compressed gas. According to the operating conditions, a set of accident scenarios that may follow the release of hydrogen is identified and an event tree analysis is carried out to determine the resulting dangerous phenomena. The impact of such phenomena is assessed in terms of damage distances. The results of the study demonstrate the high hazardousness of cryo-compression and highlight that liquid and compressed hydrogen are the preferable solutions from a safety standpoint.

Wildfires approaching the Wildland-Industrial Interfaces can be a serious threat for industrial items located at the plant boundary. These items are typically storage tanks involving large amounts of hazardous substances. Ensuring their integrity is of paramount importance to prevent the wildfire spread inside the industrial plant, avoiding the occurrence of major accidents such as fires, explosions and toxic releases. A methodology for the evaluation of safety distances between tanks and vegetation for the protection from wildfire hazard was developed and applied to a case study. The outcomes provide useful information for an effective emergency response planning in the case of wildfire. Moreover, the results obtained rise concern about the appropriateness of clearance areas between the vegetation and industrial areas currently adopted.

Decarbonization represent one of the main challenges of the maritime transport sector for the near future. As recent international environmental regulations have set more stringent emission limits, the use of liquefied natural gas (LNG) as alternative ship fuel has proven to be a viable and less-polluting solution, compared to conventional oil-based fuels. However, LNG is a highly flammable substance and safety aspects need to be assessed thoroughly, especially for its use on board passenger ships. Two different gas engine concepts are typically used for ship propulsion: Low-Pressure Dual Fuel (LPDF) and High-Pressure Dual Fuel (HPDF) engines. Regardless of the gas engine technology, the fuel gas supply system process equipment is located inside a specific enclosed space, the fuel preparation room (FPR), that can be sited below deck. Given this background, this study aims to investigate the consequences of LNG pool fires occurring inside a confined space, assessing the influence of different operating conditions. Credible loss of containment events were identified to define the characteristics of LNG pools. Furthermore, LNG pool fires were simulated using the fire dynamic simulator (FDS) to estimate the radiation heat flux received by the process equipment installed inside the FPR and to assess the possibility of experiencing accident escalation on board. To evaluate the effect of forced mechanical ventilation of the FPR, two different cases were modelled: one assuming the standard functioning of the ventilation system, while the other one considered a halted air supply inside the FPR with a working exhaust system only. The outcomes of this study provide useful data for the consequence estimation of small-scale LNG pool fires occurring inside enclosed spaces, also addressing the possibility of accident escalation on board LNG-fuelled ships.

Digitalization has significantly improved productivity and efficiency within the chemical industry. Distributed Control Systems and extensive use of sensor networks enable advanced control strategies and increase optimization opportunities. On the other hand, chemical plants are increasingly complex, equipment is highly interlinked, and it is more difficult to describe the system dynamics through first principles. Finding the root causes of process upsets and predicting dangerous deviations in process conditions is often challenging. Advanced and dynamic tools are needed to grant safe and stable operations in such a complex and multivariate environment. In this context, Machine Learning techniques may be used to exploit and retrieve knowledge from the large amount of data that chemical plants produce and store on a daily basis. Data-driven methods may be adopted to develop predictive models and support a proactive approach to process safety. The study aims to develop Machine Learning techniques to improve the response of control room operators during critical events. Specifically, alarm data originated in an upper-tier Seveso site have been collected, cleaned, and analyzed to identify periods of intense alarm activity. Alarm behavior following operator responses has been evaluated to assess whether the actions were adequate to prevent future alarm occurrences. In doing so, alarm events that reoccur within 30 minutes after an operator acknowledgment have been identified and labeled. Subsequently, a hybrid classification algorithm was trained to predict the probability that a critical alarm reoccurs after being acknowledged by the operator. This predictive tool might be used to support the operator’s decision-making process and focus his/her attention on critical alarms that are more likely to occur again in the near future.

Hydrogen is a promising zero-emission fuel that could play a key role in the transition towards a more sustainable economy. It is regarded as a possible fuel for the future that could replace traditional fossil fuels and reduce the consequent amount of greenhouse gas emissions. In contrast with the undeniable benefits introduced by the use of hydrogen as a fuel, its hazardous properties rise concern from the safety standpoint. A potential loss of integrity of the storage equipment might lead to severe consequences such as fires and explosions. The current investigation aims at quantifying the impact of the outcomes of an unexpected hydrogen release from the storage vessels designed for hydrogen-powered buses. A comparative analysis is carried out considering the different conditions in which hydrogen is currently stored on board: as a high-pressure gas, as a cryogenic liquid or as a cryo-compressed gas. According to the operating conditions, a set of accident scenarios that may follow the release of hydrogen is identified and an event tree analysis is carried out to determine the resulting dangerous phenomena. The impact of such phenomena is assessed in terms of damage distances. The results of the study demonstrate the high hazardousness of cryo-compression and highlight that liquid and compressed hydrogen are the preferable solutions from a safety standpoint. [ABSTRACT FROM AUTHOR]

An in-vitro model of human bone marrow mesenchymal stem cells (hBM-MSCs) myogenic commitment by synergic effect of a differentiation media coupled with human primary skeletal myoblasts (hSkMs) co-culture was developed adopting both conventional static co-seeding and perfused culture systems. Static co-seeding provided a notable outcome in terms of gene expression with a significant increase of Desmin (141-fold) and Myosin heavy chain II (MYH2, 32-fold) at day 21, clearly detected also by semi-quantitative immunofluorescence. Under perfusion conditions, myogenic induction ability of hSkMs on hBM-MSCs was exerted by paracrine effect with an excellent gene overexpression and immunofluorescence detection of MYH2 protein; furthermore, due to the dynamic cell culture in separate wells, western blot data were acquired confirming a successful cell commitment at day 14. A significant increase of anti-inflammatory cytokine gene expression, including IL-10 and IL-4 (15-fold and 11-fold, respectively) at day 14, with respect to the pro-inflammatory cytokines IL-12A (7-fold at day 21) and IL-1β (1.4-fold at day 7) was also detected during dynamic culture, confirming the immunomodulatory activity of hBM-MSCs along with commitment events. The present study opens interesting perspectives on the use of dynamic culture based on perfusion as a versatile tool to study myogenic events and paracrine cross-talk compared to the simple co-seeding static culture. [ABSTRACT FROM AUTHOR]

Hydrogen is one of the most suitable candidates in replacing heavy hydrocarbons. Liquefaction of fuels is one of the most effective processes to increase their low density. This is critical especially in large-scale or mobile applications such as in the maritime or aeronautical fields. A potential loss of integrity of the cryogenic storage equipment might lead to severe consequences due to the properties of these substances (e.g. high flammability). For this reason, this critical event must be avoided. The aim of this study is to analyse the behaviour of the cryogenic vessel and its lading when it is exposed to a fire and understand how to prevent a catastrophic rupture of the tank during this accident scenario. A two-dimensional computational fluid dynamic (CFD) analysis is carried out on a cryogenic liquid hydrogen (LH2) vessel to investigate its thermal response when engulfed in a fire. The model accounts for the evaporation and condensation of the substance and can predict the tank pressurization rate and temperature distribution. It is assumed that the vessel is completely engulfed in the fire (worst-case scenario). The CFD model is validated with the outcomes of a small-scale fire test of an LH2 tank. Critical indications on the dynamic response of the cryogenic tank involved in a worst-case accident scenario are provided. Tank pressurisation and temperature distributions of the case study can be exploited to provide conservative estimations of the time to failure (TTF) of the vessel. These outcomes represent useful information to support the emergency response to this type of accident scenario and can aid the selection of appropriate and effective safety barriers to prevent the complete destruction of the tank. [ABSTRACT FROM AUTHOR]

Decarbonization represent one of the main challenges of the maritime transport sector for the near future. As recent international environmental regulations have set more stringent emission limits, the use of liquefied natural gas (LNG) as alternative ship fuel has proven to be a viable and less-polluting solution, compared to conventional oil-based fuels. However, LNG is a highly flammable substance and safety aspects need to be assessed thoroughly, especially for its use on board passenger ships. Two different gas engine concepts are typically used for ship propulsion: Low-Pressure Dual Fuel (LPDF) and High-Pressure Dual Fuel (HPDF) engines. Regardless of the gas engine technology, the fuel gas supply system process equipment is located inside a specific enclosed space, the fuel preparation room (FPR), that can be sited below deck. Given this background, this study aims to investigate the consequences of LNG pool fires occurring inside a confined space, assessing the influence of different operating conditions. Credible loss of containment events were identified to define the characteristics of LNG pools. Furthermore, LNG pool fires were simulated using the fire dynamic simulator (FDS) to estimate the radiation heat flux received by the process equipment installed inside the FPR and to assess the possibility of experiencing accident escalation on board. To evaluate the effect of forced mechanical ventilation of the FPR, two different cases were modelled: one assuming the standard functioning of the ventilation system, while the other one considered a halted air supply inside the FPR with a working exhaust system only. The outcomes of this study provide useful data for the consequence estimation of small-scale LNG pool fires occurring inside enclosed spaces, also addressing the possibility of accident escalation on board LNG-fuelled ships. [ABSTRACT FROM AUTHOR]

Wildfires approaching the Wildland-Industrial Interfaces can be a serious threat for industrial items located at the plant boundary. These items are typically storage tanks involving large amounts of hazardous substances. Ensuring their integrity is of paramount importance to prevent the wildfire spread inside the industrial plant, avoiding the occurrence of major accidents such as fires, explosions and toxic releases. A methodology for the evaluation of safety distances between tanks and vegetation for the protection from wildfire hazard was developed and applied to a case study. The outcomes provide useful information for an effective emergency response planning in the case of wildfire. Moreover, the results obtained rise concern about the appropriateness of clearance areas between the vegetation and industrial areas currently adopted. [ABSTRACT FROM AUTHOR]

Central Italy Earthquakes occurred in 2016 pointed out once more the vulnerability of Cultural Heritage (CH), especially for what concerns bell-towers since they tend to get dramatically damaged due to their considerable slenderness and deterioration, endangering their surroundings and making their preservation fundamental. This work presents the results of the study carried out on four different isolated masonry bell towers, located in Ferrara province (Italy); the parameters of the materials were deduced by calibrating Finite Element Models (FEMs) using the data collected during an investigation campaign conducted with a wired accelerometric sensor system, since it was not possible to apply destructive methodologies. Dynamic data were extracted through the application of two Operational Modal Analysis (OMA) identification techniques: the Enhanced Frequency Domain Decomposition (EFDD) and the Stochastic Subspace Identification (SSI) methodology. Particular attention was devoted to the use of MAC matrix in the validation of the mode shapes results. [ABSTRACT FROM AUTHOR]

A methodology to conduct the Response Gap Analysis (RGA) for offshore oil spill emergency activities was developed, able to identify, for a given area and a given time period, if the response, which depends on the combination of the environmental factors affecting the performance of the contingency actions, is favourable, impaired, or ineffective. The necessity for offshore oil and gas operators to perform a RGA derives from the provisions of the Directive 2013/30/EU on safety of offshore oil and gas operations. In this Directive, "oil spill response effectiveness" means the effectiveness of spill response systems in combating an oil spill, on the basis of the "analysis of the frequency, duration, and timing of environmental conditions that would preclude a response. Furthermore, the assessment of oil spill response effectiveness is to be expressed as a percentage of time that such conditions are not present and is to include a description of the operating limitations placed on the installations concerned as a result of that assessment". Firstly, a gap analysis was conducted, aimed at highlighting the state of the art of RGA. The various literature reports on RGA are based on different environmental factors, as well as on different response strategies. A detailed analysis of the available information allowed identifying 9 environmental factors to be included in RGA: the wind speed, the wave height, the air temperature, the wind chill, the superstructure icing, the daylight / darkness conditions, the horizontal visibility, the cloud ceiling, and the sea ice coverage. In addition, also the shoreline distance and the bathymetry, which are location specific factors, could impair the response. Thus, a total number of 11 "environmental factors" is taken into account in the new RGA methodology. The definition of threshold values to be applied to each environmental factor was also addressed. In literature, usually two limit values are adopted and three zones are identified: a green zone, where the factor is favourable to the response; a yellow zone, where it is marginal, and a red zone, where it is unfavourable. Technical reports were analysed in order to retrieve the limit values of the environmental factors mentioned. Thus, a set of threshold values was proposed for mechanical recovery, application of dispersants by vessel and by aircraft, and in-situ burning. As a further step, the criteria adopted to combine the environmental factors in order to evaluate the effectiveness of the response were investigated. All the most recent studies identify for the response a green zone for the favourable response, a yellow zone corresponding to the impaired response, and a red one, where the response is ineffective. This criterion is adopted in the RGA method developed in the present study. The RGA methodology was implemented in a software code, which was applied to a case study area, allowing the validation of the RGA procedure. [ABSTRACT FROM AUTHOR]

Wildland Urban Interface (WUI) fires are posing tremendous management challenges in terms of civil protection and fire mitigation. Many critical factors are contributing and increasing the risk at the WUI, such as the presence of all sorts of fuels whose hazard is poorly characterized and disregarded by residents, the existence of vulnerable elements in houses and industrial installations and the absence of standards that deal with the WUI problem at the homeowner/ property scale. The WUIVIEW project aims at developing an innovative risk management tool that will help WUI communities to adapt in order to face the new generation of forest fires. This is being done by designing, setting up and testing a virtual workbench service for the performance-based analysis of fire environments in the surroundings of buildings at the WUI. In this framework, a methodological approach for the assessment of LPG domestic tanks vulnerability under fire exposure at the WUI has been developed. The present work provides a demonstration of such methodology through a realistic case study, together with an overview of the WUIVIEW project activities. [ABSTRACT FROM AUTHOR]

In the present work the value of the degree of the area swept by the polymer chain due to an electrical force for a given mesostructure was related to the corresponding value of the dielectric strength. This value was deduced from the electric inclusion formalism applied to dynamic mechanical analysis (DMA) studies conducted under high electric field, which were performed in commercial ethylene-propylene-diene M-class rubber (EPDM); used for the housing of polymeric electrical insulators. EPDM samples with different arrangements of the polymer chains and crystalline degree, promoted by controlled neutron irradiation were studied. Several characterization techniques, as infrared absorption spectroscopy (IR), differential scanning calorimetry (DSC), positron annihilation lifetime spectroscopy (PALS) and dielectric strength (DS) were also used. The relationship between the DS and the degree of movement of polymer chains promoted by electrical forces coming from the electric field applied in a non destructive test as the DMA was successfully established. In fact, a larger empty space in the sample leads to larger areas swept by the polymer chains during bending under the application of the field strength in the dynamic mechanical analysis tests. Therefore, an increase in the capability of movement of charges occurs, corresponding to smaller dielectric strength values. Crystallinity improves the dielectric strength due to the increase in the internal stresses which decreases the capability of movement of the polymer chains and electric carriers by electric forces. [ABSTRACT FROM PUBLISHER]

The article presents a study on the relationship between damping behavior, magnetic response and order degree in iron (Fe)-based allows. The study found that the magnetic response of ordered allows depends on the order degree. A large hysteresis between the heating and cooling during thermal cycles was exhibited by the damping behavior for Fe-6A1-9Si.

The organization of chromosomes into euchromatin and heterochromatin is one of the most enigmatic aspects of genome evolution. For a long time, heterochromatin was considered to be a genomic wasteland, incompatible with gene expression. However, recent studies – primarily conducted in Drosophila melanogaster – have shown that this peculiar genomic component performs important cellular functions and carries essential genes. New research on the molecular organization, function and evolution of heterochromatin has been facilitated by the sequencing and annotation of heterochromatic DNA. About 450 predicted genes have been identified in the heterochromatin of D. melanogaster, indicating that the number of active genes is higher than had been suggested by genetic analysis. Most of the essential genes are still unknown at the molecular level, and a detailed functional analysis of the predicted genes is difficult owing to the lack of mutant alleles. Far from being a peculiarity of Drosophila, heterochromatic genes have also been found in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Oryza sativa and Arabidopsis thaliana, as well as in humans. The presence of expressed genes in heterochromatin seems paradoxical because they appear to function in an environment that has been considered incompatible with gene expression. In the future, genetic, functional genomic and proteomic analyses will offer powerful approaches with which to explore the functions of heterochromatic genes and to elucidate the mechanisms driving their expression.Heredity (2007) 98, 3–12. doi:10.1038/sj.hdy.6800877; published online 1 November 2006 [ABSTRACT FROM AUTHOR]

A 32 year old woman, gravid 1, nulliparous, was admitted to our department at 11 weeks and 2 days of gestation after being diagnosed with cervical pregnancy. She was unsuccessfully treated with methotrexate for 5 days. On the fifth day after admission she underwent bilateral uterine artery angiographic embolization followed by vacuum evacuation and curettage of the cervical canal. A Foley catheter was also inserted in the cervical canal and left in place for 4 days. The patient was discharged in good condition on the seventh postoperative day. [ABSTRACT FROM AUTHOR]

A 32 year old woman, gravid 1, nulliparous, was admitted to our department at 11 weeks and 2 days of gestation after being diagnosed with cervical pregnancy. She was unsuccessfully treated with methotrexate for 5 days. On the fifth day after admission she underwent bilateral uterine artery angiographic embolization followed by vacuum evacuation and curettage of the cervical canal. A Foley catheter was also inserted in the cervical canal and left in place for 4 days. The patient was discharged in good condition on the seventh postoperative day [ABSTRACT FROM PUBLISHER]

A set of teaching materials dealing with harmonic oscillations was developed as part of a research project investigating the influence of different pedagogical tools on physics learning. The materials incorporate simulation software and laboratory activities associated with Teacher and Student Units. The project involved research groups at seven Italian universities and the materials have been trialled in high schools nation‐wide. This paper describes the experimental protocol for the use of these materials in pilot classes and the evaluation of student learning and teacher training results. The intervention was found to improve physics education at school praxis level and to promote understanding of the content area as well as appreciation of the role of experiments and simulations in the construction of scientific knowledge [ABSTRACT FROM PUBLISHER]