20 research outputs found
Performance assessment of flamelet models in flame-resolved les of a high Karlovitz methane/air stratified premixed jet flame
Tabulated flamelets are commonly used in turbulent combustion modeling due to their relatively low computational cost, which is attractive in industrial applications. However, these models require assumptions of tabulated chemistry and subgrid-scale models for control variable distributions, both of which may contribute to modeling errors. In the present work, large-eddy simulation (LES) with tabulated flamelets is employed to study a laboratory-scale high Karlovitz number stratified premixed jet flame that was investigated recently using direct numerical simulation (DNS). Particularly, the LES resolves properly the transported control variables at a near DNS level, mitigating the errors from subgrid-scale modeling of control variable distributions. Five different flamelet tables are tested in the current work, including the conditional mean from the DNS, counterflow stratified premixed 1D flames with and without differential diffusion, freely propagating premixed 1D flames, and 0D autoigniting plug-flow reactors. The LES results show that although the flamelet tables perform differently for the instantaneous distributions of the progress variable source term, their mean distributions are similar. The mean and rms (root mean square) radial profiles for axial velocity and temperature from the LES with different flamelet tables are in good agreement with those from the DNS; more evident discrepancies are observed for the CH 2 O mass fraction radial profiles. Finally, the flame structures are examined in temperature space with the table from conditional means of the DNS having the best performance, as expected
Delayed Cord Clamping versus Early Cord Clamping in Elective Cesarean Section: A Randomized Controlled Trial
Background: Delaying cord clamping is recommended in order to assure placental transfusion. However, the evidence on cord management in elective cesarean section (CS) is limited. Objective: To compare delayed cord clamping (DCC) with early cord clamping (ECC) with regard to postnatal adaptation in neonates born through elective CS. Methods: All neonates born 6539 weeks' gestation born through elective CS were assigned to either the DCC or the ECC arm at a 1:1 ratio according to a computer-generated, randomized sequence. The primary outcome was the hematocrit at day 2 of life. Secondary outcomes included: Preductal oxygen saturation and heart rate during the first 10 min of life; transcutaneous bilirubin at day 3; and neonatal blood pressures in the first 3 days of life. Additional outcomes included: Time to first spontaneous breath; temperature at admission to normal nursery; weight at discharge; and maternal blood losses. Results: Eighty neonates were randomized to the DCC (n = 40) or the ECC (n = 40) arm. The hematocrit at day 2 was significantly higher in the DCC arm than in the ECC arm (mean difference: 6%; 95% CI 3-8; p < 0.0001). The secondary outcome measures were not statistically different between the two arms. No infants needed phototherapy for hyperbilirubinemia during their hospital stay. Conclusions: Delaying cord clamping beyond 60 s increases the hematocrit at day 2 in neonates born through elective CS, without affecting maternal blood losses. Our findings suggest that DCC should be recommended in elective CS, but further studies are warranted to assess long-term outcomes
Relationship-based care model in paediatrics: A randomized controlled trial to implement the parents\u2019 perception of the quality of nursing care
Aim: To evaluate whether the application of the Relationship-based care model as a new treatment, called "Take 5\ua0min", affects the level of anxiety, depression, and perceived quality of nursing care of parents of paediatric patients and the work satisfaction of the nursing staff. Design: Single-blind randomized controlled trial. Methods: The trial was performed from February\u2013July 2016. The trial was conducted with one intervention (N\ua0=\ua0101) and one control group (N\ua0=\ua090). Nurses applied the treatment named \u201cTake 5 Minutes\u201d, which consisted of dedicating some short time (from 5 to 10\ua0min) to the relationship with the parents using specifically designed communication strategies. The primary outcome was the evaluation of anxiety and depression of parents; the secondary was the parent perceived quality of nursing care. Results: In the experimental group, participants had a lower level of anxiety and depression and highlighted that the effect of the \u201cTake 5 Minutes\u201d was proportional to the initial seriousness of parents\u2019 anxiety and depression. Higher scores for the perception of the quality of care were given from the parents of the experimental group. Conclusion: The \u201cTake 5 Minutes\u201d treatment offered to parents of paediatric patients demonstrated significant improvements in terms of their anxiety, depression, and perceived quality of nursing care. Impact: Caregivers of paediatric patients are subject to psychological disorders such as depression and anxiety. The communication by the nursing community is of fundamental importance in the management of anxiety and depression in the caregivers of hospitalized patients. Caregivers who received the \u201cTake 5 Minutes\u201d treatment demonstrated a significant decrease in anxiety and depression compared with the control group caregivers. The perceived level of quality of nursing care showed a significant increase in the group of caregivers who received the T5M treatment. The RBC model does not require extra costs for health organizations and can be applied during the usual practice of care. Practices such as T5M could become part of paediatric patient care guidelines and nurses should be trained to apply them. Trial Registration Number: Padua Research: ID No. 10,034; ClinicalTrials.gov: ID No. NCT04199429
SAPERO: un nuovo strumento per analisi di sicurezza nel settore della radioterapia avanzata
La realizzazione di elevati standard di sicurezza nell’impiego di tecnologie avanzate per la radioterapia, in cui non è
presente memoria storica a causa dell’innovatività, pone la necessità di svolgere analisi basate sull’uso di nuovi
approcci incentrati su una visione olistica del processo, efficaci nell’individuare elementi di informazione aggiuntivi
rispetto ad un’applicazione classica. Nel presente lavoro viene descritto un nuovo strumento di valutazione, denominato
SAPERO (La SicurezzA del PazientE: tecniche avanzate ed innovative per la valutazione del rischio di eventi
indesiderati all'interno del percorso assistenziale nel settore RadioterapicO) che consente all’analista di impiegare in
maniera integrata le tecniche Hierarchical Task Analysis (HTA); Failure Mode Effects and Criticality Analysis (FMECA);
Cognitive Task Analysis (CTA); Human Error Assessment Reduction Technique (HEART). Gli approcci metodologici
sono stati opportunamente modificati per migliorare le loro prestazioni nel settore in studio. Alcuni cambiamenti hanno
riguardato l’applicazione della teoria fuzzy in FMECA e il ricorso in HEART ad un approccio linguistico per la
determinazione di alcuni dei fattori di calcolo necessari per la valutazione della probabilità di fallimento dell’operatore.
Viene descritta l’applicazione di SAPERO ad un caso studio relativo alle procedure di somministrazione di cure con
tomoterapia elicoidale presso il reparto di Radioterapia dell’ospedale ARNAS Civico di Palermo. I risultati ottenuti hanno
consentito di fornire suggerimenti volti a migliorare il processo esaminato