Understanding and mitigating cascading crises in the global interconnected system

Cascading crises and disasters in the global interconnected system are emerging topics in today's disaster risk reduction research. The primary objective is improving the capability of our societies to cope with such events and mitigate their detrimental consequences through an evolved understanding of their nature. Rather than being merely considered as an outcome of low-probability/high-impact processes, cascading events can be associated with the cross-scale accumulation of vulnerability paths constituted by events waiting to happen. In this context, instead of focusing solely on triggering events, it seems important to point out the interactions orienting the escalation of secondary emergencies through vulnerability paths. This special issue integrates those emerging aspects with an operational approach that considers cascades as the complex, non-linear escalation of secondary emergencies. Key topics addressed by the contributions include: cross-domain modelling of interdependent systems; decision support systems; economic impact assessment of critical events; and cascades in the built environment, in social domains, and in applied emergency management. Our conclusions support the work of academia, and of public and private stakeholders, by providing a comprehensive analysis of the topic for the improvement of theory, the assessment of resilience, the formulation of policies for managing crises, and operational planning for emergencies

Linking healthcare and societal resilience during the Covid-19 pandemic

Coronavirus disease 2019 (Covid-19) has highlighted the link between public healthcare and the broader context of operational response to complex crises. Data are needed to support the work of the emergency services and enhance governance. This study develops a Europe-wide analysis of perceptions, needs and priorities of the public affected by the Covid-19 emergency. An online multilingual survey was conducted from mid-May until mid-July 2020. The questionnaire investigates perceptions of public healthcare, emergency management and societal resilience. In total, N = 3029 valid answers were collected. They were analysed both as a whole and focusing on the most represented countries (Italy, Romania, Spain and the United Kingdom). Our findings highlight some perceived weaknesses in emergency management that are associated with the underlying vulnerability of the global interconnected society and public healthcare systems. The spreading of the epidemic in Italy represented a ‘tipping point’ for perceiving Covid-19 as an ‘emergency’ in the surveyed countries. The respondents uniformly suggested a preference for gradually restarting activities. We observed a tendency to ignore the cascading effects of Covid-19 and possible concurrence of threats. Our study highlights the need for practices designed to address the next phases of the Covid-19 crisis and prepare for future systemic shocks. Cascading effects that could compromise operational capacity need to be considered more carefully. We make the case for the reinforcement of cross-border coordination of public health initiatives, for standardization in business continuity management, and for dealing with the recovery at the European level

Analytical modeling and characterization of ring beam profiles for high-power lasers used in industrial manufacturing

Active fibre lasers are widely used in the industry for different manufacturing applications ranging from cutting, to welding and additive manufacturing. The recent introduction of the multiple-core fibre lasers allows these sources to flexibly change the Power Density Distribution (PDD) from conventional Gaussian profiles towards ring shapes. While the advantages of the novel beam shapes over the conventional ones are still being explored, the need for modeling tools to define the PDD shapes becomes more evident. This work studies the analytical modeling of Gaussian to ring profiles with the aim to move towards standardized parameters referable to the manufacturing processes. The proposed models combine Gaussian and annular components to define the novel beam shapes. Among the different models assessed, the Torus and Multi-Gaussian approaches exhibited the best fitting quality thus enabling the definition of descriptive metrics of the PDD. The modeling framework developed was validated on an industrial Laser Powder Bed Fusion (LPBF) system with a double-core light source. The beam shape variation along the propagation axis was assessed to analyze the effect of defocusing using the developed beam parameters. Eventually, the best performing model was furtherly validated with a bead on plate experiment to explain how the model coefficients can be jointly exploited to predict the material response using a Gaussian or a ring beam profile

Tailoring the microstructure of Fe-2.9wt.%Si alloy in laser powder bed fusion using in-source beam shaping

Tuning the irradiance profile of the laser beam opens up new possibilities in terms of controlling the thermal field the material is subjected to during laser powder bed fusion (PBF-LB/M). This control can be exploited to manipulate the material's microstructure. In this work, a contemporary high power fibre laser with in-source beam shaping capability was used to test different irradiance profiles ranging from Gaussian to ring during the PBF-LB/M of Fe-2.9wt.%Si alloy. This soft magnetic alloy is used in electrical machines, and its magnetic properties are known to be correlated to the microstructure. Initially, the experimental work assessed the influence of peak and ring irradiance levels on densification and grain morphology. In a second experimental run, the influence of the beam profile on the conventionally employed energy density was verified. The results demonstrated that the use of combined Gaussian-ring profiles offers a method for manipulating grain size and shape from a columnar towards an equiaxed shape, without requiring a change in the scan strategy

Electromagnetic shielding properties of LPBF produced Fe2.9wt.%Si alloy

Ferromagnetic materials are used in various applications such as rotating electrical machines, wind turbines, electromagnetic shielding, transformers, and electromagnets. Compared to hard magnetic materials, their hysteresis cycles are featured by low values of coercive magnetic field and high permeability. The application of additive manufacturing to ferromagnetic materials is gaining more and more attraction. Indeed, thanks to a wider geometrical freedom, new topological optimized shapes for stator/rotor shapes can be addressed to enhance electric machines performances. However, the properties of the laser powder bed fusion (LPBF) processed alloy compared to conventionally produced counterpart must be still addressed. Accordingly, this paper presents for the first time the use of the LPBF for the manufacturing of Fe2.9wt.%Si electromagnetic shields. The process parameter selection material microstructure and the magnetic shielding factor are characterized

Characterization of LPBF Produced Fe2.9wt.%Si for Electromagnetic Actuator

This study aims to produce Fe2.9wt.%Si ferromagnetic material via laser powder bed fusion (L-PBF) for the realization of electromagnetic actuators (EMA). This study is necessary as there are no documents in scientific literature regarding the manufacturing of Iron-Silicon plungers using the L-PBF additive manufacturing (AM) technique. The microstructure, and magnetic properties were characterized using various techniques. The results indicate that the samples produced via L-PBF process exhibit good magnetic properties (μ = 748, H C= 87.7 [A/m] ) especially after annealing treatment at 1200° C for 1h (μ = 3224, H C= 69.1 [A/m]), making it a promising material for use in electromagnetic actuators

Two patients with history of STEC-HUS, posttransplant recurrence and complement gene mutations

Hemolytic uremic syndrome (HUS) is a disease of microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure. About 90% of cases are secondary to infections by Escherichia coli strains producing Shiga-like toxins (STEC-HUS), while 10% are associated with mutations in genes encoding proteins of complement system (aHUS). We describe two patients with a clinical history of STEC-HUS, who developed end-stage renal disease (ESRD) soon after disease onset. They received a kidney transplant but lost the graft for HUS recurrence, a complication more commonly observed in aHUS. Before planning a second renal transplantation, the two patients underwent genetic screening for aHUS-associated mutations that revealed the presence of a heterozygous CFI mutation in patient #1 and a heterozygous MCP mutation in patient #2, and also in her mother who donated the kidney. This finding argues that the two cases originally diagnosed as STEC-HUS had indeed aHUS triggered by STEC infection on a genetic background of impaired complement regulation. Complement gene sequencing should be performed before kidney transplantation in patients who developed ESRD following STEC-HUS since they may be undiagnosed cases of aHUS, at risk of posttransplant recurrence. Furthermore, genetic analysis of donors is mandatory before living-related transplantation to exclude carriers of HUS-predisposing mutations. Two patients with a clinical history of D+ hemolytic uremic syndrome associated with Shiga-toxin-producing 0157:H7 E. coli and recurrence in the kidney graft carry heterozygous mutations in the genes encoding complement factor I (patient 1) and membrane cofactor protein (patient 2). © Copyright 2013 The American Society of Transplantation and the American Society of Transplant Surgeons