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BackgroundThe COVID-19 pandemic overwhelmed hospitals, forcing adjustments including discharging patients earlier and limiting intensive care unit (ICU) utilization. This study aimed to evaluate ICU admissions and length of stay (LOS) for blunt trauma patients (BTPs).MethodsA retrospective review of COVID (3/19/20-6/30/20) versus pre-COVID (3/19/19-6/30/19) BTPs at eleven trauma centers was performed. Multivariable analysis was used to identify risk factors for ICU admission.Results12,744 BTPs were included (6942 pre-COVID vs. 5802 COVID). The COVID cohort had decreased mean LOS (3.9 vs. 4.4 days, p = 0.029), ICU LOS (0.9 vs. 1.1 days, p < 0.001), and rate of ICU admission (22.3% vs. 24.9%, p = 0.001) with no increase in complications or mortality compared to the pre-COVID cohort (all p > 0.05). On multivariable analysis, the COVID period was associated with decreased risk of ICU admission (OR = 0.82, CI 0.75-0.90, p < 0.001).ConclusionsBTPs had decreased LOS and associated risk of ICU admission during COVID, with no corresponding increase in complications or mortality.

COVID-19 stay-at-home (SAH) orders were impactful on adolescence, when social interactions affect development. This has the potential to change adolescent trauma. A post-hoc multicenter retrospective analysis of adolescent (13-17 years-old) trauma patients (ATPs) at 11 trauma centers was performed. Patients were divided into 3 groups based on injury date: historical control (CONTROL:3/19/2019-6/30/2019, before SAH (PRE:1/1/2020-3/18/2020), and after SAH (POST:3/19/2020-6/30/2020). The POST group was compared to both PRE and CONTROL groups in separate analyses. 726 ATPs were identified across the 3 time periods. POST had a similar penetrating trauma rate compared to both PRE (15.8% vs 13.8%, P = .56) and CONTROL (15.8% vs 14.5%, P = .69). POST also had a similar rate of suicide attempts compared to both PRE (1.2% vs 1.5%, P = .83) and CONTROL (1.2% vs 2.1%, P = .43). However, POST had a higher rate of drug positivity compared to CONTROL (28.6% vs 20.6%, P = .032), but was similar in all other comparisons of alcohol and drugs to PRE and POST periods (all P > .05). Hence ATPs were affected differently than adults and children, as they had a similar rate of penetrating trauma, suicide attempts, and alcohol positivity after SAH orders. However, they had increased drug positivity compared to the CONTROL, but not PRE group.

PurposeThe COVID-19 pandemic resulted in increased penetrating trauma and decreased length of stay (LOS) amongst the adult trauma population, findings important for resource allocation. Studies regarding the pediatric trauma population are sparse and mostly single-center. This multicenter study examined pediatric trauma patients, hypothesizing increased penetrating trauma and decreased LOS after the 3/19/2020 stay-at-home (SAH) orders.MethodsA multicenter retrospective analysis of trauma patients ≤ 17 years old presenting to 11 centers in California was performed. Demographic data, injury characteristics, and outcomes were collected. Patients were divided into three groups based on injury date: 3/19/2019-6/30/2019 (CONTROL), 1/1/2020-3/18/2020 (PRE), 3/19/2020-6/30/2020 (POST). POST was compared to PRE and CONTROL in separate analyses.Results1677 patients were identified across all time periods (CONTROL: 631, PRE: 479, POST: 567). POST penetrating trauma rates were not significantly different compared to both PRE (11.3 vs. 9.0%, p = 0.219) and CONTROL (11.3 vs. 8.2%, p = 0.075), respectively. POST had a shorter mean LOS compared to PRE (2.4 vs. 3.3 days, p = 0.002) and CONTROL (2.4 vs. 3.4 days, p = 0.002). POST was also not significantly different than either group regarding intensive care unit (ICU) LOS, ventilator days, and mortality (all p > 0.05).ConclusionsThis multicenter retrospective study demonstrated no difference in penetrating trauma rates among pediatric patients after SAH orders but did identify a shorter LOS.

COVID-19 stay-at-home (SAH) orders were impactful on adolescence, when social interactions affect development. This has the potential to change adolescent trauma. A post-hoc multicenter retrospective analysis of adolescent (13-17 years-old) trauma patients (ATPs) at 11 trauma centers was performed. Patients were divided into 3 groups based on injury date: historical control (CONTROL:3/19/2019-6/30/2019, before SAH (PRE:1/1/2020-3/18/2020), and after SAH (POST:3/19/2020-6/30/2020). The POST group was compared to both PRE and CONTROL groups in separate analyses. 726 ATPs were identified across the 3 time periods. POST had a similar penetrating trauma rate compared to both PRE (15.8% vs 13.8%, P = .56) and CONTROL (15.8% vs 14.5%, P = .69). POST also had a similar rate of suicide attempts compared to both PRE (1.2% vs 1.5%, P = .83) and CONTROL (1.2% vs 2.1%, P = .43). However, POST had a higher rate of drug positivity compared to CONTROL (28.6% vs 20.6%, P = .032), but was similar in all other comparisons of alcohol and drugs to PRE and POST periods (all P > .05). Hence ATPs were affected differently than adults and children, as they had a similar rate of penetrating trauma, suicide attempts, and alcohol positivity after SAH orders. However, they had increased drug positivity compared to the CONTROL, but not PRE group.

BackgroundThe COVID-19 pandemic overwhelmed hospitals, forcing adjustments including discharging patients earlier and limiting intensive care unit (ICU) utilization. This study aimed to evaluate ICU admissions and length of stay (LOS) for blunt trauma patients (BTPs).MethodsA retrospective review of COVID (3/19/20-6/30/20) versus pre-COVID (3/19/19-6/30/19) BTPs at eleven trauma centers was performed. Multivariable analysis was used to identify risk factors for ICU admission.Results12,744 BTPs were included (6942 pre-COVID vs. 5802 COVID). The COVID cohort had decreased mean LOS (3.9 vs. 4.4 days, p = 0.029), ICU LOS (0.9 vs. 1.1 days, p < 0.001), and rate of ICU admission (22.3% vs. 24.9%, p = 0.001) with no increase in complications or mortality compared to the pre-COVID cohort (all p > 0.05). On multivariable analysis, the COVID period was associated with decreased risk of ICU admission (OR = 0.82, CI 0.75-0.90, p < 0.001).ConclusionsBTPs had decreased LOS and associated risk of ICU admission during COVID, with no corresponding increase in complications or mortality.

PurposeThe COVID-19 pandemic resulted in increased penetrating trauma and decreased length of stay (LOS) amongst the adult trauma population, findings important for resource allocation. Studies regarding the pediatric trauma population are sparse and mostly single-center. This multicenter study examined pediatric trauma patients, hypothesizing increased penetrating trauma and decreased LOS after the 3/19/2020 stay-at-home (SAH) orders.MethodsA multicenter retrospective analysis of trauma patients ≤ 17 years old presenting to 11 centers in California was performed. Demographic data, injury characteristics, and outcomes were collected. Patients were divided into three groups based on injury date: 3/19/2019-6/30/2019 (CONTROL), 1/1/2020-3/18/2020 (PRE), 3/19/2020-6/30/2020 (POST). POST was compared to PRE and CONTROL in separate analyses.Results1677 patients were identified across all time periods (CONTROL: 631, PRE: 479, POST: 567). POST penetrating trauma rates were not significantly different compared to both PRE (11.3 vs. 9.0%, p = 0.219) and CONTROL (11.3 vs. 8.2%, p = 0.075), respectively. POST had a shorter mean LOS compared to PRE (2.4 vs. 3.3 days, p = 0.002) and CONTROL (2.4 vs. 3.4 days, p = 0.002). POST was also not significantly different than either group regarding intensive care unit (ICU) LOS, ventilator days, and mortality (all p > 0.05).ConclusionsThis multicenter retrospective study demonstrated no difference in penetrating trauma rates among pediatric patients after SAH orders but did identify a shorter LOS.

BackgroundThe COVID-19 pandemic resulted in a statewide stay-at-home (SAH) order in California beginning March 19, 2020, forcing large-scale behavioral changes and taking an emotional and economic toll. The effects of SAH orders on the trauma population remain unknown. We hypothesized an increase in rates of penetrating trauma, gunshot wounds, suicide attempts, and domestic violence in the Southern California trauma population after the SAH order.MethodsA multicenter retrospective analysis of all trauma patients presenting to 11 American College of Surgeons levels I and II trauma centers spanning seven counties in California was performed. Demographic data, injury characteristics, clinical data, and outcomes were collected. Patients were divided into three groups based on injury date: before SAH from January 1, 2020, to March 18, 2020 (PRE), after SAH from March 19, 2020, to June 30, 2020 (POST), and a historical control from March 19, 2019, to June 30, 2019 (CONTROL). POST was compared with both PRE and CONTROL in two separate analyses.ResultsAcross all periods, 20,448 trauma patients were identified (CONTROL, 7,707; PRE, 6,022; POST, 6,719). POST had a significantly increased rate of penetrating trauma (13.0% vs. 10.3%, p < 0.001 and 13.0% vs. 9.9%, p < 0.001) and gunshot wounds (4.5% vs. 2.4%, p = 0.002 and 4.5% vs. 3.7%, p = 0.025) compared with PRE and CONTROL, respectively. POST had a suicide attempt rate of 1.9% and a domestic violence rate of 0.7%, which were similar to PRE (p = 0.478, p = 0.514) and CONTROL (p = 0.160, p = 0.618).ConclusionThis multicenter Southern California study demonstrated an increased rate of penetrating trauma and gunshot wounds after the COVID-19 SAH orders but no difference in attempted suicide or domestic violence rates. These findings may provide useful information regarding resource utilization and a target for societal intervention during the current or future pandemic(s).Level of evidenceEpidemiological, level IV.

PurposeThere is mounting evidence that surgical patients with COVID-19 have higher morbidity and mortality than patients without COVID-19. Infection is prevalent amongst the trauma population, but any effect of COVID-19 on trauma patients is unknown. We aimed to evaluate the effect of COVID-19 on a trauma population, hypothesizing increased mortality and pulmonary complications for COVID-19-positive (COVID) trauma patients compared to propensity-matched COVID-19-negative (non-COVID) patients.MethodsA retrospective analysis of trauma patients presenting to 11 Level-I and II trauma centers in California between 1/1/2019-6/30/2019 and 1/1/2020-6/30/2020 was performed. A 1:2 propensity score model was used to match COVID to non-COVID trauma patients using age, blunt/penetrating mechanism, injury severity score, Glasgow Coma Scale score, systolic blood pressure, respiratory rate, and heart rate. Outcomes were compared between the two groups.ResultsA total of 20,448 trauma patients were identified during the study period. 53 COVID trauma patients were matched with 106 non-COVID trauma patients. COVID patients had higher rates of mortality (9.4% vs 1.9%, p = 0.029) and pneumonia (7.5% vs. 0.0%, p = 0.011), as well as a longer mean length of stay (LOS) (7.47 vs 3.28 days, p < 0.001) and intensive care unit LOS (1.40 vs 0.80 days, p = 0.008), compared to non-COVID patients.ConclusionThis multicenter retrospective study found increased rates of mortality and pneumonia, as well as a longer LOS, for COVID trauma patients compared to a propensity-matched cohort of non-COVID patients. Further studies are warranted to validate these findings and to elucidate the underlying pathways responsible for higher mortality in COVID trauma patients.

BackgroundThe COVID-19 pandemic resulted in a statewide stay-at-home (SAH) order in California beginning March 19, 2020, forcing large-scale behavioral changes and taking an emotional and economic toll. The effects of SAH orders on the trauma population remain unknown. We hypothesized an increase in rates of penetrating trauma, gunshot wounds, suicide attempts, and domestic violence in the Southern California trauma population after the SAH order.MethodsA multicenter retrospective analysis of all trauma patients presenting to 11 American College of Surgeons levels I and II trauma centers spanning seven counties in California was performed. Demographic data, injury characteristics, clinical data, and outcomes were collected. Patients were divided into three groups based on injury date: before SAH from January 1, 2020, to March 18, 2020 (PRE), after SAH from March 19, 2020, to June 30, 2020 (POST), and a historical control from March 19, 2019, to June 30, 2019 (CONTROL). POST was compared with both PRE and CONTROL in two separate analyses.ResultsAcross all periods, 20,448 trauma patients were identified (CONTROL, 7,707; PRE, 6,022; POST, 6,719). POST had a significantly increased rate of penetrating trauma (13.0% vs. 10.3%, p < 0.001 and 13.0% vs. 9.9%, p < 0.001) and gunshot wounds (4.5% vs. 2.4%, p = 0.002 and 4.5% vs. 3.7%, p = 0.025) compared with PRE and CONTROL, respectively. POST had a suicide attempt rate of 1.9% and a domestic violence rate of 0.7%, which were similar to PRE (p = 0.478, p = 0.514) and CONTROL (p = 0.160, p = 0.618).ConclusionThis multicenter Southern California study demonstrated an increased rate of penetrating trauma and gunshot wounds after the COVID-19 SAH orders but no difference in attempted suicide or domestic violence rates. These findings may provide useful information regarding resource utilization and a target for societal intervention during the current or future pandemic(s).Level of evidenceEpidemiological, level IV.

PurposeThere is mounting evidence that surgical patients with COVID-19 have higher morbidity and mortality than patients without COVID-19. Infection is prevalent amongst the trauma population, but any effect of COVID-19 on trauma patients is unknown. We aimed to evaluate the effect of COVID-19 on a trauma population, hypothesizing increased mortality and pulmonary complications for COVID-19-positive (COVID) trauma patients compared to propensity-matched COVID-19-negative (non-COVID) patients.MethodsA retrospective analysis of trauma patients presenting to 11 Level-I and II trauma centers in California between 1/1/2019-6/30/2019 and 1/1/2020-6/30/2020 was performed. A 1:2 propensity score model was used to match COVID to non-COVID trauma patients using age, blunt/penetrating mechanism, injury severity score, Glasgow Coma Scale score, systolic blood pressure, respiratory rate, and heart rate. Outcomes were compared between the two groups.ResultsA total of 20,448 trauma patients were identified during the study period. 53 COVID trauma patients were matched with 106 non-COVID trauma patients. COVID patients had higher rates of mortality (9.4% vs 1.9%, p = 0.029) and pneumonia (7.5% vs. 0.0%, p = 0.011), as well as a longer mean length of stay (LOS) (7.47 vs 3.28 days, p < 0.001) and intensive care unit LOS (1.40 vs 0.80 days, p = 0.008), compared to non-COVID patients.ConclusionThis multicenter retrospective study found increased rates of mortality and pneumonia, as well as a longer LOS, for COVID trauma patients compared to a propensity-matched cohort of non-COVID patients. Further studies are warranted to validate these findings and to elucidate the underlying pathways responsible for higher mortality in COVID trauma patients.

BackgroundThe rapid spread of coronavirus disease 2019 in the United States led to a variety of mandates intended to decrease population movement and "flatten the curve." However, there is evidence some are not able to stay-at-home due to certain disadvantages, thus remaining exposed to both coronavirus disease 2019 and trauma. We therefore sought to identify any unequal effects of the California stay-at-home orders between races and insurance statuses in a multicenter study utilizing trauma volume data.MethodsA posthoc multicenter retrospective analysis of trauma patients presenting to 11 centers in Southern California between the dates of January 1, 2020, and June 30, 2020, and January 1, 2019, and June 30, 2019, was performed. The number of trauma patients of each race/insurance status was tabulated per day. We then calculated the changes in trauma volume related to stay-at-home orders for each race/insurance status and compared the magnitude of these changes using statistical resampling.ResultsCompared to baseline, there was a 40.1% drop in total trauma volume, which occurred 20 days after stay-at-home orders. During stay-at-home orders, the average daily trauma volume of patients with Medicaid increased by 13.7 ± 5.3%, whereas the volume of those with Medicare, private insurance, and no insurance decreased. The average daily trauma volume decreased for White, Black, Asian, and Latino patients with the volume of Black and Latino patients dropping to a similar degree compared to White patients.ConclusionThis retrospective multicenter study demonstrated that patients with Medicaid had a paradoxical increase in trauma volume during stay-at-home orders, suggesting that the most impoverished groups remain disproportionately exposed to trauma during a pandemic, further exacerbating existing health disparities.

The main objective of the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project is validation of aero-hydro-servo-elastic simulation tools for offshore wind turbines (OWTs) through comparison of simulated results to the response data of physical systems. Phase III of the OC5 project validates OWT models against the measurements recorded on a Senvion 5M wind turbine supported by the OWEC Quattropod from the alpha ventus offshore wind farm. The following operating conditions of the wind turbine were chosen for the validation: (1) idling below the cut-in wind speed, (2) rotor-nacelle assembly (RNA) rotation maneuver below the cut-in wind speed, (3) power production below and above the rated wind speed, and (4) shutdown. A number of validation load cases were defined based on these operating conditions. The following measurements were used for validation: (1) strains and accelerations recorded on the support structure and (2) pitch, yaw, and azimuth angles, generator speed, and electrical power recorded from the RNA. Strains were not directly available from the majority of the OWT simulation tools; therefore, strains were calculated based on out-of-plane bending moments, axial forces, and cross-sectional properties of the structural members. The simulation results and measurements were compared in terms of time series, discrete Fourier transforms, power spectral densities, and probability density functions of strains and accelerometers. A good match was achieved between the measurements and models setup by OC5 Phase III participants.

Phase I of the OC6 project is focused on examining why offshore wind design tools underpredict the response (loads/motion) of the OC5-DeepCwind semisubmersible at its surge and pitch natural frequencies. Previous investigations showed that the underprediction was primarily related to nonlinear hydrodynamic loading, so two new validation campaigns were performed to separately examine the different hydrodynamic load components. In this paper, we validate a variety of tools against this new test data, focusing on the ability to accurately model the low-frequency loads on a semisubmersible floater when held fixed under wave excitation and when forced to oscillate in the surge direction. However, it is observed that models providing better load predictions in these two scenarios do not necessarily produce a more accurate motion response in a moored configuration.

Phase I of the OC6 project is focused on examining why offshore wind design tools underpredict the response (loads/motion) of the OC5-DeepCwind semisubmersible at its surge and pitch natural frequencies. Previous investigations showed that the underprediction was primarily related to nonlinear hydrodynamic loading, so two new validation campaigns were performed to separately examine the different hydrodynamic load components. In this paper, we validate a variety of tools against this new test data, focusing on the ability to accurately model the low-frequency loads on a semisubmersible floater when held fixed under wave excitation and when forced to oscillate in the surge direction. However, it is observed that models providing better load predictions in these two scenarios do not necessarily produce a more accurate motion response in a moored configuration.

Wind farm load assessment is typically conducted using Computational Fluid Dynamics (CFD) or aeroelastic simulations, which need a lot of computer power. A number of applications, for example wind farm layout optimisation, turbine lifetime estimation and wind farm control, requires a simplified but sufficiently detailed model for computing the turbine fatigue load. In addition, the effect of turbine curtailment is particularly important in the calculation of the turbine loads. Therefore, this paper develops a fast and computationally efficient method for wind turbine load assessment in a wind farm, including the wake effects. In particular, the turbine fatigue loads are computed using a surrogate model that is based on the turbine operating condition, for example, power set-point and turbine location, and the ambient wind inflow information. The Turbine to Farm Loads (T2FL) surrogate model is constructed based on a set of high fidelity aeroelastic simulations, including the Dynamic Wake Meandering model and an artificial neural network that uses the Bayesian Regularisation (BR) and Levenberg–Marquardt (LM) algorithms. An ensemble model is used that outperforms model predictions of the BR and LM algorithms independently. Furthermore, a case study of a two turbine wind farm is demonstrated, where the turbine power set-point and fatigue loads can be optimised based on the proposed surrogate model. The results show that the downstream turbine producing more power than the upstream turbine is favourable for minimising the load. In addition, simulation results further demonstrate that the accumulated fatigue damage of turbines can be effectively distributed amongst the turbines in a wind farm using the power curtailment and the proposed surrogate model.

The use of down-regulation control strategies on turbines offers a means of stabilising the grid or improving the efficiency of the wind farm. Nonetheless, these de-rating strategies are often imposed upon an existing blade-pitch control structure, resulting in sub-optimal or poor performance. In particular, such an approach would potentially deteriorate the robustness of the rotor speed control loop and excite other turbine dynamics. Thus, this work proposes a blade-pitch control design for de-rating operation, where the strategy takes into account the changes in the aerodynamic characteristics of the turbine caused by down-regulation. Most importantly, the proposed controller retained the desired control bandwidth and robustness properties in both nominal and de-rating operations. Numerical simulations showed that an improvement on the pitch activities during down-regulation could lead to better reductions in the fatigue loads of some key turbine components.

Wind turbines are expected to be able to participate in the ancillary services normally provided by the conventional power plants, as the penetration of the wind energy in the electricity grid is increasing. As a result, the turbines are needed to be able to control their active power. Constraining the possible output power, i.e. decreasing the power to less than the maximum or rated power, is therefore important for the wind turbine control system. When a turbine is operating under a de-rating strategy, the operating points of the turbine, i.e. the steady state blade pitch and the tip speed ratio, change compared to the normal case and this needs to be considered within the control design. This paper is to study the influence of de-rating on the turbine controller gain scheduling and its effect to power output and component fatigue damage. The results show that the WT response is refined through tuning under the different down-regulation operation points which results in less fatigue damage of the key turbine components.

An increasing number of wind turbines are expected to be able to participate in the ancillary services that would normally be provided by conventional power plants, as the penetration of the wind energy in the electricity grid is increasing. Specifically, the turbines are needed to be able to control their active power based on the operator command. Constraining the possible output power, i.e. decreasing the power to less than the maximum or rated power, is therefore important for the wind turbine control system. When a turbine is operating under a de-rating strategy, the operating points of the turbine, i.e. the steady-state blade pitch and the tip speed ratio, change compared to the normal case and this needs to be considered within the controller design. Thus, this paper is to study the influence of the de-rating on the turbine controller gain-scheduling and its effect to power output and fatigue damage of the key turbine components. The results show that the wind turbine response is refined through tuning under the different down-regulation operation points, that translate into less fatigue damage of the key turbine components. For a typical multi-megawatt turbine, it is found that the main component lifetime damage can be reduced substantially. In numerical terms, there are up to 6.5% for the tower BM in fore-aft direction and 2.7% for the blade root flapwise direction, which can lead in a prolonged operational lifetime of the wind turbine.

Background: The purpose was to examine the incidence of positive cultures in a highly susceptible subset of trauma patients admitted to the surgical intensive care unit (SICU) for mechanical ventilation and to examine the impact of their timing on outcomes. Patients and Methods: A retrospective review was conducted of blunt trauma patients admitted to the SICU for mechanical ventilation at a level I trauma center over a five-year period. All urine, blood, and sputum cultures were abstracted. Patients with at least one positive culture were compared with those with negative or no cultures. The primary outcome was mortality. A Cox regression model with a time-dependent variable was utilized to calculate the adjusted hazard ratio (AHR). Results: The median age of 635 patients meeting inclusion criteria was 46 and 74.2% were male. A total of 298 patients (46.9%) had at least one positive culture, with 28.9% occurring within two days of admission. Patients with positive cultures were more likely to be severely injured with an injury severity score (ISS) 16 (68.5% vs. 45.1%, p<0.001). Overall mortality was 22%. Patients who had their first positive culture within two and three days from admission had a significantly higher AHR for mortality (AHR: 14.46, p<0.001 and AHR: 10.59, p=0.028, respectively) compared to patients with a positive culture at day six or later. Conclusions: Early positive cultures are common among trauma patients requiring mechanical ventilation and are associated with higher mortality. Early identification with damage control cultures obtained on admission to aid with early targeted treatment might be justified.

Aero-elastic solver predictions are compared to measured data from the NENUPHAR’s 1HS prototype, with a focus on the blade loads. Two solvers are investigated, namely the HAWC2 solver, and DeepLinesWindTM, respectively based on a linear and a non-linear formulation of the Timoshenko beam theory. Various aerodynamic models are used, from simple Multiple Streamtube models up to the Actuator-Cylinder flow model and 2D/3D Vortex flow solvers. A special attention is also given to the influence of the dynamic stall on the results. Aero-elastic solvers predictions are accurate and fit well with the measured blade loads, but this work emphasizes the fact that suitable aerodynamic model and stall model should be used.

Three characteristic derating strategies on the upstream wind Turbine are studied and the load impact to the downstream one is assessed. These are defined as minimum/maximum rotor speeds (minRS, maxRS) and minimum thrust (minT) modes. Derating factors of 20% and 40% on available power are applied together with 4 and 7 diameters WT interspace. The study is based on aeroelastic simulations of a 2MW generic WT model including wake effects. The results show that below rated wind speed (8m/s) the downstream WT blade flap fatigue loads are minimized when the upfront WT is derated with the minRS strategy. The maxRS mode returns always the highest loads. When the WTS are aligned with the wind direction (full wake situation) the load levels for minRS and mint strategies are almost equal. Above rated wind speed (16m/s) the tendency is the same as at 8m/s. Finally, the fore-aft fatigue loads on the tower base and the main bearing yaw moment follow the same trends as the blade for both below and above rated wind speed.

This report is part of the EUDP Blatigue project, Fast and efficient fatigue test of large wind turbine blades. In the study the Siemens B75 blade loads are computed using HAWC2 aeroelastic code. The blade is coupled in the DTU 10MW rwt tower and nacelle structure within HAWC2. Furthermore the basic DTU WE controller is used. The aim is to evaluate the blade fatigue and ultimate loads based on the IEC 61400-1 ed.3 standard. The results are further used in the project for the set-up and testing of the real blade at the DTU Risø Large Scale Facility. In the first part the model properties are summarized. Then the IEC load cases are simulated using the HAWC2 code and the analysis is focused on the blade performance. A blade load comparison between HAWC2 and the Siemens results is presented together with a summary of the uncertainties related with the present analysis. The work is funded by the EUDP project BLATIGUE: Fast and efficient fatigue test of large wind turbine blades under project number 64016-0023 which is gratefully acknowledged. Several contributions have been made in the model set-up as well as in the interpretation of the results from Torben J. Larsen, Anders M. Hansen, Kim Branner, Perer Berring and Federico Belloni who are gratefully acknowledged.

The main objective of the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project, is validation of aero-hydro-servo-elastic simulation tools for offshore wind turbines (OWTs) through comparison of simulated results to the response data of physical systems. Phase III of the OC5 project analyzes the Senvion 5M wind turbine supported by the OWEC Quattropod from the alpha ventus offshore wind farm. This paper shows results of the verification of the OWT models (code-to-code comparison). A subsequent publication will focus on their validation (comparison of simulated results to measured physical system response data). Based on the available data, the participants of Phase III set up numerical models of the OWT in their simulation tools. It was necessary to verify and to tune these models. The verification and tuning were performed against an OWT model available at the University of Stuttgart – Stuttgart Wind Energy (SWE) and documentation provided by Senvion and OWEC Tower. A very good match was achieved between the results from the reference SWE model and models set up by OC5 Phase III participants.

This paper presents a study on derating wind turbine power levels in a wind farm and the associated loads on down wind placed wind turbines. This is done by derating the wind farm power output for certain periods of time. Derating can be done in different ways by adjusting the rotor speed and blade pitch on the individual turbines which also has a direct impact on the turbine component loads. The paper studies three characteristic derating strategies on the upstream wind Turbine (WT) and the corresponding load impact on the downstream one. These are defined as minimum/maximum rotor speeds (minRS, maxRS) and minimum thrust (minT) modes. Derating factors of 20% and 40% on available power are applied together with 4 and 7 diameters WT interspace. The study is based on aeroelastic simulations of a 2MW generic WT model including wake effects. The results show that below rated wind speed (8m/s) the downstream WT blade flap fatigue loads are minimized when the upfront WT is derated with the minRS or minT strategy. The maxRS mode returns around 2% percent higher loads. The load levels for minRS and minT strategies are almost equal. Above rated wind speed (16m/s) the trend is the same as at 8m/s with a bit higher difference on load levels, up to 6% percent at tighter interspace bewteen maxRS strategy and the other two. The fore-aft fatigue loads on the tower base and the main bearing yaw moment follow the same trends as the blade for both below and above rated wind speed.Finally, it is also found that there is a correlation on the load levels and the wind deficit values. In all cases up to around ±10 degrees incoming wind direction the wake deficit from the maxRS control strategy is higher and the load levels follow the same trend. This is an important outcome and links the control strategies directly to the wake deficit due to the upstream WT operation.

This report is part of the EUDP Blatigue project, Fast and efficient fatigue test of large wind turbine blades. In the study the Siemens B49 blade loads are computed using HAWC2 aeroelastic code. The blade is coupled in a generic wind turbine tower and nacelle structure within HAWC2. Furthermore the basic DTU WE controller is used. The aim is to evaluate the blade fatigue and ultimate loads based on the IEC 61400-1 ed.3 standard. The results are further used in the project for the set-up and testing of the real blade at the DTU Risø Large Scale Facility. In the first part the model properties are summarized. Then the IEC load cases are simulated using the HAWC2 code and the analysis is focused on the blade performance. A blade load comparison between HAWC2 and the Siemens results is presented together with a summary of the uncertainties related with the present analysis. Finally, an analysis is performed on a potential way to compute the blade lifetime fatigue damage based on few time series instead of running the full design load basis. The work is funded by the EUDP project BLATIGUE: Fast and efficient fatigue test of large wind turbine blades under project number 64016- 0023 which is gratefully acknowledged. Several contributions have been made in the model set-up as well as in the interpretation of the results from Torben J. Larsen, Anders M. Hansen, Kim Branner, Perer Berring and Federico Belloni who are gratefully acknowledged.

BACKGROUND: Approximately half of trauma patients develop post-traumatic depression. It is suggested that beta-blockade impairs trauma memory recollection, reducing depressive symptoms. This study investigates the effect of early beta-blockade on depression following severe traumatic injuries in patients without significant brain injury. METHODS: Patients were identified by retrospectively reviewing the trauma registry at an urban university hospital between 2007 and 2011. Severe extracranial injuries were defined as extracranial injuries with Abbreviated Injury Scale score ≥3, intracranial Abbreviated Injury Scale score <3 and an Injury Severity Score ≥16. In-hospital deaths and patients prescribed antidepressant therapy ≤1 year prior to admission were excluded. Patients were stratified into groups based on pre-admission beta-blocker status. The primary outcome was post-traumatic depression, defined as receiving antidepressants ≤1 year following trauma. RESULTS: Five hundred and ninety-six patients met the inclusion criteria with 11.4% prescribed pre-admission beta-blockade. Patients receiving beta-blockers were significantly older (57 ± 18 vs. 42 ± 17 years, p < 0.001) with lower Glasgow Coma Scale score (12 ± 3 vs. 14 ± 2, p < 0.001). The beta-blocked cohort spent significantly longer in hospital (21 ± 20 vs. 15 ± 17 days, p < 0.01) and intensive care (4 ± 7 vs. 3 ± 5 days, p = 0.01). A forward logistic regression model was applied and predicted lack of beta-blockade to be associated with increased risk of depression (OR 2.7, 95% CI 1.1-7.2, p = 0.04). After adjusting for group differences, patients lacking beta-blockers demonstrated an increased risk of depression (AOR 3.3, 95% CI 1.2-8.6, p = 0.02). CONCLUSIONS: Pre-admission beta-blockade is associated with a significantly reduced risk of depression following severe traumatic injury. Further investigation is needed to determine the beneficial effects of beta-blockade in these instances.

This paper summarizes the findings from Phase II of the Offshore Code Comparison, Collaboration, Continued, with Correlation project. The project is run under the International Energy Agency Wind Research Task 30, and is focused on validating the tools used for modeling offshore wind systems through the comparison of simulated responses of select system designs to physical test data. Validation activities such as these lead to improvement of offshore wind modeling tools, which will enable the development of more innovative and cost-effective offshore wind designs.

The paper studies the applicability of the IEC 61400-1 ed.3, 2005 International Standard of wind turbine minimum design requirements in the case of an onshore Darrieus VAWT and compares the results of basic Design Load Cases (DLCs) with those of a 3-bladed HAWT. The study is based on aeroelastic computations using the HAWC2 aero-servo-elastic code A 2-bladed 5 MW VAWT rotor is used based on a modified version of the DeepWind rotor For the HAWT simulations the NREL 3-bladed 5 MW reference wind turbine model is utilized Various DLCs are examined including normal power production, emergency shut down and parked situations, from cut-in to cut-out and extreme wind conditions. The ultimate and 1 Hz equivalent fatigue loads of the blade root and turbine base bottom are extracted and compared in order to give an insight of the load levels between the two concepts. According to the analysis the IEC 61400-1 ed.3 can be used to a large extent with proper interpretation of the DLCs and choice of parameters such as the hub-height. In addition, the design drivers for the VAWT appear to differ from the ones of the HAWT. Normal operation results in the highest tower bottom and blade root loads for the VAWT, where parked under storm situation (DLC 6.2) and extreme operating gust (DLC 2.3) are more severe for the HAWT. Turbine base bottom and blade root edgewise fatigue loads are much higher for the VAWT compared to the HAWT. The interpretation and simulation of DLC 6.2 for the VAWT lead to blade instabilities, while extreme wind shear and extreme wind direction change are not critical in terms of loading of the VAWT structure. Finally, the extreme operating gust wind condition simulations revealed that the emerging loads depend on the combination of the rotor orientation and the time stamp that the frontal passage of gust goes through the rotor plane.

This paper describes the development of a wind turbine (WT) component lifetime fatigue load variation map within an offshore wind farm. A case study on the offshore wind farm Horns Rev I is conducted with this purpose, by quantifying wake effects using the Dynamic Wake Meandering (DWM) method, which has previously been validated based on CFD, Lidar and full scale load measurements. Fully coupled aeroelastic load simulations using turbulent wind conditions are conducted for all wind directions and mean wind speeds between cut-in and cut-out using site specific turbulence level measurements. Based on the mean wind speed and direction distribution, the representative 20-year lifetime fatigue loads are calculated. It is found that the heaviest loaded WT is not the same when looking at blade root, tower top or tower base components. The blade loads are mainly dominated by the wake situations above rated wind speed and the highest loaded blades are in the easternmost row as the dominating wind direction is from West. Regarding the tower components, the highest loaded WTs are also located towards the eastern central location. The turbines with highest power production are, not surprisingly, the ones facing a free sector towards west and south. The power production results of few turbines are compared with SCADA data. The results of this paper are expected to have significance for operation and maintenance planning, where the schedules for inspection and service activities can be adjusted to the requirements arising from the varying fatigue levels. Furthermore, the results can be used in the context of remaining fatigue lifetime assessment and planning of decommissioning.

In the last years, large scale Vertical Axis Wind Turbines (VAWTs) are re-gaining a general interest in the wind energy sector as an alternative to Horizontal Axis Wind Turbines (HAWTs). However, the existing standards and guidelines for wind turbine certification do not include specific requirements for VAWT rotors. This thesis aims to study the adequacy and applicability of the IEC 61400-1 ed.3, 2005 International Standard minimum design requirements, when it is applied on multi-megawatt VAWTs. This is accomplished by simulating a VAWT aeroelastic model under various Design Load Cases (DLCs) and analysing the results. The motivation comes from the recent years scientific research and developments which revealed that a VAWT can be beneficial in some types of applications in comparison with a HAWT. As a result, a minimum engineering integrity proof for VAWTs is needed before the installation and operation phase as in HAWT. The work is split into two main phases. The first copes with the construction of a reliable large scale VAWT aeroelastic model which serves as the basis for the analysis. A 5 MW 2-bladed VAWT aeroelastic model is built based on the “DeepWind” concept. Since blade instabilities were reported the "Sandia 34 m, 500 kW VAWT test bed" is up-scaled and used as guidance for the modification of the blade structural properties. In addition, the selection and validation of an aeroelastic code able to compute the VAWT aerodynamics and loads under different environmental conditions and wind turbine states is investigated. The study has been conducted through a special project by the author as part of this thesis. It was meant to study and apply an aeroelastic code by constructing a VAWT aeroelastic model. The Sandia 34 m, 500 kW VAWT was modelled and simulated with HAWC2 aeroelastic code, showing good agreement with experimental data published by Sandia National Laboratories. In the second part is studied the adequacy and applicability of the aforementioned i, EWEM, Wind Energy, Aerospace Engineering

In the last years, large scale Vertical Axis Wind Turbines (VAWTs) are re-gaining a general interest in the wind energy sector as an alternative to Horizontal Axis Wind Turbines (HAWTs). However, the existing standards and guidelines for wind turbine certification do not include specific requirements for VAWT rotors. This thesis aims to study the adequacy and applicability of the IEC 61400-1 ed.3, 2005 International Standard minimum design requirements, when it is applied on multi-megawatt VAWTs. This is accomplished by simulating a VAWT aeroelastic model under various Design Load Cases (DLCs) and analysing the results. The motivation comes from the recent years scientific research and developments which revealed that a VAWT can be beneficial in some types of applications in comparison with a HAWT. As a result, a minimum engineering integrity proof for VAWTs is needed before the installation and operation phase as in HAWT. The work is split into two main phases. The first copes with the construction of a reliable large scale VAWT aeroelastic model which serves as the basis for the analysis. A 5 MW 2-bladed VAWT aeroelastic model is built based on the “DeepWind” concept. Since blade instabilities were reported the "Sandia 34 m, 500 kW VAWT test bed" is up-scaled and used as guidance for the modification of the blade structural properties. In addition, the selection and validation of an aeroelastic code able to compute the VAWT aerodynamics and loads under different environmental conditions and wind turbine states is investigated. The study has been conducted through a special project by the author as part of this thesis. It was meant to study and apply an aeroelastic code by constructing a VAWT aeroelastic model. The Sandia 34 m, 500 kW VAWT was modelled and simulated with HAWC2 aeroelastic code, showing good agreement with experimental data published by Sandia National Laboratories. In the second part is studied the adequacy and applicability of the aforementioned i, EWEM, Wind Energy, Aerospace Engineering

ImportanceBRCA mutation carriers are at increased risk of developing breast cancer. However, the incidence of breast cancer after a diagnosis of epithelial ovarian cancer (EOC), one of the tubal/peritoneal cancers collectively referred to as pelvic serous carcinomas, is not well known. Optimal breast cancer surveillance and detection for these patients have also not been well characterized.ObjectivesTo determine the incidence of breast cancer after a diagnosis of EOC and to evaluate the need for breast cancer surveillance for these patients.Design, setting, and participantsA retrospective database review of 364 patients who underwent BRCA mutation testing for EOC (stages I-IV) between 1998 and 2012 at an academic medical center with gynecologic and breast cancer centers.Main outcomes and measuresIncidence of breast cancer and methods of surveillance.ResultsOf 364 patients, 135 (37.1%) were found to carry a germline BRCA1 or BRCA2 mutation. The mean age of patients at diagnosis of EOC was 49.5 years (range, 28-89 years). Of the 135 patients, 12 (8.9%) developed breast cancer. The median time from diagnosis of EOC to diagnosis of breast cancer was 50.5 months. Annual mammography was performed for 80 patients (59.3%), with annual magnetic resonance imaging of the breasts performed for 60 patients (44.4%). Thirteen patients (9.6%) underwent a bilateral prophylactic mastectomy at a median of 23 months following EOC diagnosis. Breast cancer was most commonly diagnosed by mammography for 7 of the 12 patients (58.3%), 3 (25.0%) of whom had a palpable mass and 2 (16.7%) of whom had incidental breast cancer detected during a prophylactic mastectomy. Seven patients with breast cancer (58.3%) underwent a bilateral mastectomy. All patients had early-stage breast cancer (stages 0-II). Four patients (33.3%) received adjuvant chemotherapy. At a median follow-up of 6.3 years, 4 of the 12 patients (33.3%) died of recurrent EOC after a diagnosis of breast cancer. The overall 10-year s