9 research outputs found

    Numerical modeling of moored floating platforms for wave energy converters using DualSPHysics

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    The DualSPHysics open-source code establishes a comprehensive and efficient framework for simulating coastal and ocean engineering structures, which has been proven to be particularly reliable in wave energy converter (WEC) simulation. In this research, the experimental data of the floating oscillating surge wave energy converter (FOSWEC), is used for validation purposes. The FOSWEC2 device developed by SANDIA National Laboratories (US) is quite complex as it has several floating parts, anchor legs and a power take-off system (PTO) connected to the pitching motion of two flaps. Kinetic energy is in fact converted from the relative rotation between the flaps and a movable frame of the platform, setting a significant challenge for the validation of the FOSWEC with time-domain integrated methods. This work proposes a first validation campaign carried out using regular waves, and considering different parameters for the definition of the PTO system. The numerical model prediction for the platform motion (surge and pitch) and the relative flap pitch angle (bow and aft) shows that the model is able to deal with multi-body dynamics interacting with wave-induced forces

    Outcomes after perioperative SARS-CoV-2 infection in patients with proximal femoral fractures: an international cohort study

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    Objectives Studies have demonstrated high rates of mortality in people with proximal femoral fracture and SARS-CoV-2, but there is limited published data on the factors that influence mortality for clinicians to make informed treatment decisions. This study aims to report the 30-day mortality associated with perioperative infection of patients undergoing surgery for proximal femoral fractures and to examine the factors that influence mortality in a multivariate analysis. Setting Prospective, international, multicentre, observational cohort study. Participants Patients undergoing any operation for a proximal femoral fracture from 1 February to 30 April 2020 and with perioperative SARS-CoV-2 infection (either 7 days prior or 30-day postoperative). Primary outcome 30-day mortality. Multivariate modelling was performed to identify factors associated with 30-day mortality. Results This study reports included 1063 patients from 174 hospitals in 19 countries. Overall 30-day mortality was 29.4% (313/1063). In an adjusted model, 30-day mortality was associated with male gender (OR 2.29, 95% CI 1.68 to 3.13, p80 years (OR 1.60, 95% CI 1.1 to 2.31, p=0.013), preoperative diagnosis of dementia (OR 1.57, 95% CI 1.15 to 2.16, p=0.005), kidney disease (OR 1.73, 95% CI 1.18 to 2.55, p=0.005) and congestive heart failure (OR 1.62, 95% CI 1.06 to 2.48, p=0.025). Mortality at 30 days was lower in patients with a preoperative diagnosis of SARS-CoV-2 (OR 0.6, 95% CI 0.6 (0.42 to 0.85), p=0.004). There was no difference in mortality in patients with an increase to delay in surgery (p=0.220) or type of anaesthetic given (p=0.787). Conclusions Patients undergoing surgery for a proximal femoral fracture with a perioperative infection of SARS-CoV-2 have a high rate of mortality. This study would support the need for providing these patients with individualised medical and anaesthetic care, including medical optimisation before theatre. Careful preoperative counselling is needed for those with a proximal femoral fracture and SARS-CoV-2, especially those in the highest risk groups. Trial registration number NCT0432364

    Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study

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