19 research outputs found
Cryogenic Hydrogen Storage Tanks Exposed to Fires: a CFD study
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
New eco-sustainable feed in aquaculture: influence of insect-based diets on the content of potentially toxic elements in the experimental model zebrafish (Danio rerio).
According to the concept of circular economy, insects represent good candidates as aquafeed ingredients. Nevertheless, there are some potential chemical risks linked with insect consumption. In this study, we reared the teleost Danio rerio, used as an experimental model, with five experimental diets characterized by increasing levels (0%, 25%, 50%, 75%, and 100%) of full-fat Hermetia illucens (Hi) prepupae, substituting for fish meal (FM) and fish oil (FO). We investigated the presence of potentially toxic elements (PTEs) Cd, Pb, Ni, As, and Hg in larval (20 days), juvenile (2 months), and adult (6 months) fish. Quantitative determinations of Cd, Pb, Ni, and As were made with an atomic absorption spectrometer; the total mercury content was determined by a direct mercury analyzer. The substitution of FM and FO with Hermetia illucens meal led to a reduction in the content of some PTEs, such as Pb, As, and Ni, in fishfeed, leading to concentrations below the legal limit of undesirable substances in animal feed. By increasing the Hi meal dietary content, we observed in the Danio rerio specimens an increase in Cd, Pb, and Ni content and a reduction in As content for all life stages. Moreover, a general increase in the content of Cd, Pb, Hg, and Ni from larvae to juvenile was measured, while the shift of Danio rerio from the juvenile to the adult stage involved a significant increase in the content of Pb, Hg, and Ni. Larvae had a reduced ability to bioaccumulate metal(loid)s compared to juveniles and adults. In conclusion, the content of PTEs in Danio rerio is influenced both by the type of diet administered and by the life stage of the animal itself. This research demonstrates the possibility of using Hi prepupae as an aquafeed ingredient without exposing fish to a chemical risk and, in perspective, allows applying these eco-sustainable diets for the breeding of edible fish species, without endangering human healt
Mobilization in early rehabilitation in intensive care unit patients with severe acquired brain injury: An observational study.
Objective: To determine whether early mobilization of patients with severe acquired brain injury, performed in the intensive/neurointensive care unit, influences functional outcome. Design: Prospective observational study. Setting: Fourteen centres in Italy. Subjects: A total of 103 consecutive patients with acquired brain injury. Methods: Clinical, neurological and functional data, including the Glasgow Coma Scale (GCS), Disability Rating Scale (DRS), the Rancho Los Amigos Levels of Cognitive Functioning (LCF), Early Rehabilitation Barthel Index (ERBI), Glasgow Outcome Scale (GOS), and Functional Independence Measure (FIM) were collected at admission and every 3–5 days until discharge from the intensive/neurointensive care unit. Patients were divided into mobilization and no mobilization groups, depending on whether they received mobilization. Data were analysed by intragroup and intergroup analysis using a multilevel regression model. Results: Sixty-eight patients were included in the mobilization group. At discharge, both groups showed significant improvements in GCS, DRS, LCF and ERBI scores. The mobilization group showed significantly better improvements in FIM cognitive, GOS and ERBI. The patients in the mobilization group stayed longer in the intensive care unit (p = 0.01) and were more likely to be discharged to intensive rehabilitation at a significantly higher rate (p = 0.002) than patients in the no mobilization group. No adverse events were reported in either group. Conclusion: Early mobilization appears to favour the clinical and functional recovery of patients with severe acquired brain injury in the intensive care unit
Care pathways models and clinical outcomes in disorders of consciousness
Objective: Patients with Disorders of consciousness, are persons with extremely low functioning levels and represent a challenge for health care systems due to their high needs of facilitating environmental factors. Despite a common Italian health care path-way for these patients, no studies have analyzed information on how each region have implemented it in its welfare system correlating data with patients’ clinical outcomes.
Materials and Methods: A multicenter observational pilot study was realized. Clinicians collected data on the care pathways of patients with Disorder of consciousness by ask-ing 90 patients’ caregivers to complete an ad hoc questionnaire through a structured phone interview. Questionnaire consisted of three sections: sociodemographic data, description of the care pathway done by the patient, and caregiver evaluation of health services and information received.Results: Seventy- three patients were analyzed. Length of hospital stay was different across the health care models and it was associated with improvement in clinical diag-nosis. In long- term care units, the diagnosis at admission and the number of caregivers available for each patient (median value=3) showed an indirect relationship with worsening probability in clinical outcome. Caregivers reported that communication with professionals (42%) and the answer to the need of information were the most critical points in the acute phase, whereas presence of Non- Governmental Organizations (25%) and availability of psychologists for caregivers (21%) were often missing during long-term care. The 65% of caregivers reported they did not know the UN Convention on the Rights of Persons with Disabilities.
Conclusion: This study highlights relevant differences in analyzed models, despite a recommended national pathway of care. Future public health considerations and ac-tions are needed to guarantee equity and standardization of the care process in all European countries
Identifying clinical complexity in patients affected by severe acquired brain injury in neurorehabilitation: a cross sectional survey
Literature shows that occurrence of comorbidities in people with severe acquired brain injury (sABI) is a common problem in rehabilitation stay. Consequently, patients could require an increase of interventions for diagnosis and treatment of clinical conditions, with a reduction of the rehabilitative take in charge for both clinical and organizational aspects
Influence of Feeding Substrates on the Presence of Toxic Metals (Cd, Pb, Ni, As, Hg) in Larvae of Tenebrio molitor: Risk Assessment for Human Consumption
none8noLarvae of Tenebrio molitor L. (Coleoptera: Tenebrionidae) are particularly suitable as novel
food for the human consumption; nevertheless, there are some potential safety risks linked with
insect consumption. In this study we investigated the presence of Cd, Pb, Ni, As, Hg in new feeding
substrates coming from solid residues generated by olive fruits processing, called olive-pomace,
and their influence on the metal content in larvae of T. molitor. Morover, bioaccumulation factor
and the mercury-selenium balance were evaluated. Analyses were carried out via graphite furnace
atomic absorption spectrophotometry for Cd, Pb, Ni, As and Se, and via Direct Mercury Analyzer for
Hg. All metal concentrations found in feeding substrates were below the legal limit of undesirable
substances in animal feed (2002/32/EC). Concentrations in larvae were in the range (mg kg1 wet
weight): Cd 0.008–0.016, Pb 0.063–0.079, Ni 0.03–0.63, As 0.021–0.023, Hg 0.12 103–0.49 103,
and Se 0.057–0.085. Statistically significant correlation between metal content in feeding substrates
and in larvae was evidenced only for Hg, which bioaccumulates. Se protects from mercury toxicity,
with a Selenium Health Benefit Value (HVBSe) of > 0. Overall, our results indicate that the risk of
exposure to metals from consumption of mealworm larvae is relatively low and in compliance with
European Union regulations.restrictedCristina Truzzi, Silvia Illuminati, Federico Girolametti, Matteo Antonucci, Giuseppe Scarponi , Sara Ruschioni, Paola Riolo, Anna AnnibaldiTruzzi, Cristina; Illuminati, Silvia; Girolametti, Federico; Antonucci, Matteo; Scarponi, Giuseppe; Ruschioni, Sara; Riolo, Paola; Annibaldi, Ann
Seasonal Evolution of Size-Segregated Particulate Mercury in the Atmospheric Aerosol Over Terra Nova Bay, Antarctica
Size-fractionated particulate mercury (PHg) measurements were performed from November 2017 to January 2018 at Terra Nova Bay (Antarctica) for the first time. Samples were collected every 10 days by a six-stage high-volume cascade impactor with size classes between 10 μm and 0.49 μm. Total PHg concentrations were maxima (87 ± 8 pg m−3) in November, then decreased to values ~40% lower and remained almost constant until the end of the sampling period (~30 pg m−3). The trimodal aerosol mass distribution reveals that from 30% to 90% of the total PHg came in the size > 1.0 μm. Hg in the two coarse fractions was probably produced by the adsorption of oxidized Hg species transported by air masses from the Antarctic plateau or produced locally by sea ice edges. PHg in accumulation mode seemed to be related to gas–particle partitioning with sea salt aerosol. Finally, average dry deposition fluxes of PHg were calculated to be 0.36 ± 0.21 ng m−2 d−1 in the accumulation mode, 47 ± 44 ng m−2 d−1 in the first coarse mode, and 37 ± 31 ng m−2 d−1 in the second coarse mode. The present work contributed to the comprehension of the Hg biogeochemical cycle, but further research studies are needed