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

Toward the recovery of a sense of self: An interpretative phenomenological analysis of patients' experience of body-oriented psychotherapy for schizophrenia

Objective: Increasing evidence supports the efficacy of body-oriented psychotherapy for schizophrenia. Yet, so far no research has investigated outcome in relation to therapy process: why and how body-oriented psychotherapy is effective. In this study we qualitatively explore participants’ experience of a manualized body-oriented psychotherapy (BPT) for schizophrenia to shed light on the process of therapeutic change. Method: We conducted in-depth interviews with 6 participants who completed a 10-week BPT group intervention. Interviews explored participants’ experience of change and helpful aspects of therapy and were analysed using interpretative phenomenological analysis. Findings: We identified 6 master themes across the interviews: (a) Being a whole: body-mind connection; (b) Being agentic and being able; (c) Being unique and worthy: being accepted for who one is; (d) Changing interactions: engaging in authentic interpersonal contact; (e) Being part of a group: feeling integrated; (f) Hope and investing in the future. Conclusion: We discuss the clinical implications for each theme and bring the findings together by describing therapeutic change in schizophrenia as a recovery of sense of self at different but interlocked levels. Moreover, we put forward recommendations for both specific and common factors for schizophrenia therapy

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

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

In Situ Hexavalent Chromium Reduction by Injection of Organic Substrates in the Aquifer

Among the innovative technologies for in situ remediation of hexavalent chromium in groundwater, bio-induced reduction is under investigation. In this process the reduction of Cr(VI) is stimulated by a strongly reducing environment, created by the injection of organic substrates that are rapidly degraded by autochthonous heterotrophic microorganisms. Tests were performed at the laboratory scale to investigate the behavior of two different organic substrates from food industry (permeate from cheese whey ultrafiltration and a waste from the brewing process), in terms of dissolved Cr(VI) abatement and kinetics, also as a function of the initial Cr(VI) concentration (5000 or 10000 μg/L). The tests showed that, under proper conditions, very low Cr(VI) concentrations (1.3 g/L) and removal efficiency up to about 100% can be obtained after 36 d incubation

Genetic structure of captive and free-ranging okapi (Okapia johnstoni) with implications for management

Breeding programs for endangered species increasingly use molecular genetics to inform their management strategies. Molecular approaches can be useful for investigating relatedness, resolving pedigree uncertainties, and for estimating genetic diversity in captive and wild populations. Genetic data can also be used to evaluate the representation of wild population genomes within captive population gene-pools. Maintaining a captive population that is genetically representative of its wild counterpart offers a means of conserving the original evolutionary potential of a species. Okapi, an even-toed ungulate, endemic to the Democratic Republic of Congo, have recently been reclassified as Endangered by the IUCN. We carried out a genetic assessment of the ex-situ okapi (Okapia johnstoni) population, alongside an investigation into the genetic structure of wild populations across their geographic range. We found that while levels of nuclear (12 microsatellite loci) genetic variation in the wild, founder and captive okapi populations were similar, mitochondrial (833 bp of Cyt b, CR, tRNA-Thr and tRNA-Pro) variation within captive okapi was considerably reduced compared to the wild, with 16 % lower haplotype diversity. Further, both nuclear and mitochondrial alleles present in captivity provided only partial representation of those present in the wild. Thirty mitochondrial haplotypes found in the wild were not found in captivity, and two haplotypes found in captivity were not found in the wild, and the patterns of genetic variation at microsatellite loci in our captive samples were considerably different to those of the wild samples. Our study highlights the importance of genetic characterisation of captive populations, even for well-managed ex-situ breeding programs with detailed studbooks. We recommend that the captive US population should be further genetically characterised to guide management of translocations between European and US captive population

Dysfunctional dopaminergic neurotransmission in asocial BTBR mice

Autism spectrum disorders (ASD) are neurodevelopmental conditions characterized by pronounced social and communication deficits and stereotyped behaviours. Recent psychosocial and neuroimaging studies have highlighted reward-processing deficits and reduced dopamine (DA) mesolimbic circuit reactivity in ASD patients. However, the neurobiological and molecular determinants of these deficits remain undetermined. Mouse models recapitulating ASD-like phenotypes could help generate hypotheses about the origin and neurophysiological underpinnings of clinically relevant traits. Here we used functional magnetic resonance imaging (fMRI), behavioural and molecular readouts to probe dopamine neurotransmission responsivity in BTBR T+ Itpr3tf/J mice (BTBR), an inbred mouse line widely used to model ASD-like symptoms owing to its robust social and communication deficits, and high level of repetitive stereotyped behaviours. C57BL/6J (B6) mice were used as normosocial reference comparators. DA reuptake inhibition with GBR 12909 produced significant striatal DA release in both strains, but failed to elicit fMRI activation in widespread forebrain areas of BTBR mice, including mesolimbic reward and striatal terminals. In addition, BTBR mice exhibited no appreciable motor responses to GBR 12909. DA D1 receptor-dependent behavioural and signalling responses were found to be unaltered in BTBR mice, whereas dramatic reductions in pre- and postsynaptic DA D2 and adenosine A2A receptor function was observed in these animals. Overall these results document profoundly compromised DA D2-mediated neurotransmission in BTBR mice, a finding that is likely to have a role in the distinctive social and behavioural deficits exhibited by these mice. Our results call for a deeper investigation of the role of dopaminergic dysfunction in mouse lines exhibiting ASD-like phenotypes, and possibly in ASD patient populations