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Lateral tower vibrations of offshore wind turbines are normally lightly damped, and large amplitude vibrations induced by wind and wave loads in this direction may significantly shorten the fatigue life of the tower. This paper proposes the modeling and control of lateral tower vibrations in offshore wind turbines using active generator torque. To implement the active control algorithm, both the mechanical and power electronic aspects have been taken into consideration. A 13-degrees-of-freedom aeroelastic wind turbine model with generator and pitch controllers is derived using the Euler–Lagrangian approach. The model displays important features of wind turbines, such as mixed moving frame and fixed frame-defined degrees-of-freedom, couplings of the tower-blade-drivetrain vibrations, as well as aerodynamic damping present in different modes of motions. The load transfer mechanisms from the drivetrain and the generator to the nacelle are derived, and the interaction between the generator torque and the lateral tower vibration are presented in a generalized manner. A three-dimensional rotational sampled turbulence field is generated and applied to the rotor, and the tower is excited by a first order wave load in the lateral direction. Next, a simple active control algorithm is proposed based on active generator torques with feedback from the measured lateral tower vibrations. A full-scale power converter configuration with a cascaded loop control structure is also introduced to produce the feedback control torque in real time. Numerical simulations have been carried out using data calibrated to the referential 5-MW NREL (National Renewable Energy Laboratory) offshore wind turbine. Cases of drivetrains with a gearbox and direct drive to the generator are considered using the same time series for the wave and turbulence loadings. Results show that by using active generator torque control, lateral tower vibrations can be significantly mitigated for both gear-driven and direct-driven wind turbines, with modest influence on the smoothness of the power output from the generator.

Summary Edgewise vibrations in wind turbine blades are lightly damped, and large amplitude vibrations induced by the turbulence may significantly shorten the fatigue life of the blade. This paper investigates the performance of tuned liquid column dampers (TLCDs) for mitigating edgewise vibrations in rotating wind turbine blades. Normally, the centrifugal acceleration at the outboard portion of a rotating blade can reach to a magnitude of 7–8 g, which makes it possible to use a TLCD with a very small mass for suppressing edgewise vibrations effectively. The parameters of the TLCD to be optimized are the mounting position, the mass ratio, the geometries, and the head loss coefficient of the damper. Based on a reduced 2‐DOF nonlinear model developed by the authors, the optimization of these parameters are carried out by minimizing the standard deviation of the edgewise tip displacement, with the consideration of both the space limitation inside the blade and the constraint of the liquid motion. The edgewise modal load for the 2‐DOF model has been calculated from a more sophisticated 13‐DOF aeroelastic wind turbine model, which includes the coupling of the blade‐tower‐drivetrain vibration and the aerodynamic damping presented in different modes. Various turbulence intensities and rotational speeds of the rotor have been considered to evaluate the performance of the TLCD. Further, the optimized damper is incorporated into the 13‐DOF model to verify the application of the decoupled optimization. The investigation shows promising results for the use of the TLCD in mitigating edgewise vibrations in wind turbine blades. Copyright © 2014 John Wiley & Sons, Ltd.

To improve the efficacy of Plasmodium falciparum malaria vaccine RTS,S/AS02, we conducted a study in 2001 in healthy, malaria-naïve adults administered RTS,S/AS02 in combination with FMP1, a recombinant merozoite surface-protein-1, C-terminal 42kD fragment. A double-blind Phase I/IIa study randomized N = 60 subjects 1:1:1:1 to one of four groups, N = 15/group, to evaluate safety, immunogenicity, and efficacy of intra-deltoid half-doses of RTS,S/AS02 and FMP1/AS02 administered in the contralateral (RTS,S + FMP1-separate) or same (RTS,S + FMP1-same) sites, or FMP1/AS02 alone (FMP1-alone), or RTS,S/AS02 alone (RTS,S-alone) on a 0-, 1-, 3-month schedule. Subjects receiving three doses of vaccine and non-immunized controls (N = 11) were infected with homologous P. falciparum 3D7 sporozoites by Controlled Human Malaria Infection (CHMI). Subjects in all vaccination groups experienced mostly mild or moderate local and general adverse events that resolved within eight days. Anti-circumsporozoite antibody levels were lower when FMP1 and RTS,S were co-administered at the same site (35.0 µg/mL: 95 % CI 20.3–63), versus separate arms (57.4 µg/mL: 95 % CI 32.3–102) or RTS,S alone (62.0 µg/mL: 95 % CI: 37.8–101.8). RTS,S-specific lymphoproliferative responses and ex vivo ELISpot CSP-specific interferon-gamma (IFN-γ) responses were indistinguishable among groups receiving RTS,S/AS02. There was no difference in antibody to FMP1 among groups receiving FMP1/AS02. After CHMI, groups immunized with a RTS,S-containing regimen had ∼ 30 % sterile protection against parasitemia, and equivalent delays in time-to-parasitemia. The FMP1/AS02 alone group showed no sterile immunity or delay in parasitemia. Co-administration of RTS,S and FMP1/AS02 reduced anti-RTS,S antibody, but did not affect tolerability, cellular immunity, or efficacy in a stringent CHMI model. Absence of efficacy or delay of patency in the sporozoite challenge model in the FMP1/AS02 group did not rule out efficacy of FMP1/AS02 in an endemic population. However, a Phase IIb trial of FMP1/AS02 in children in malaria-endemic Kenya did not demonstrate efficacy against natural infection. ClinicalTrials.gov identifier: NCT01556945.

Background The human leukocyte antigen system (HLA) is divided into two classes involved in antigen presentation: class I presenting intracellular antigens and class II presenting extracellular antigens. While susceptibility to infections is correlated with the HLA system, data on associations between HLA genotypes and Malassezia- related skin diseases (MRSD) are lacking. Thus, the objective of this study was to investigate associations between HLA alleles and MRSD. Materials and methods Participants in The Danish Blood Donor Study (2010–2018) provided questionnaire data on life style, anthropometric measures, and registry data on filled prescriptions. Genotyping was done using Illumina Infinium Global Screening Array, and HLA alleles were imputed using the HIBAG algorithm. Cases and controls were defined using filled prescriptions on topical ketoconazole 2% as a proxy of MRSD. Logistic regressions assessed associations between HLA alleles and MRSD adjusted for confounders and Bonferroni corrected for multiple tests. Results A total of 9455 participants were considered MRSD cases and 24,144 participants as controls. We identified four risk alleles B*57:01, OR 1.19 (95% CI: 1.09–1.31), C*01:02, OR 1.19 (95% CI: 1.08–1.32), C*06:02, OR 1.14 (95% CI: 1.08–1.22), and DRB1*01:01, OR 1.10 (95% CI: 1.04–1.17), and two protective alleles, DQB1*02:01, OR 0.89 (95% CI: 0.85–0.94), and DRB1*03:01, OR 0.89 (95% CI: 0.85–0.94). Conclusion Five novel associations between HLA alleles and MRSD were identified in our cohort, and one previous association was confirmed. Future studies should assess the correlation between Malassezia antigens and antigen-binding properties of the associated HLA alleles.

BackgroundFluctuations in tumour necrosis factor inhibitor (TNFi) drug levels in patients with inflammatory arthritis (IA) during disease activity-guided tapering is not well described.ObjectivesTo compare TNFi drug-levels in the tapering group, relative to the control group, from baseline to month 18 based on data from the BIODOPT trial.MethodsBIODOPT was designed as a pragmatic, multicentre, randomised controlled, open-label trial (EudraCT 2017-001970-41) of 18 months duration [1]. Patients with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) in sustained (≥12 month) low disease activity (LDA) and treated with TNFi at baseline were enrolled and randomised into a disease activity-guided tapering or control in a 2:1 ratio. Blood samples at baseline and month 18 were analysed for TNFi drug levels. Based on previous research, the TNFi drug level category was considered intermediate if values were between: adalimumab 5.0-8.0 mg/L, certolizumab pegol 14.7-40.0 mg/L, etanercept 1.8-4.6 mg/L, golimumab 1.0-3.0 mg/L, or infliximab 1.6-5.0 mg/L. Values greater or lesser were considered as high or low TNFi category, respectively. A mixed Poisson regression with robust variance estimator was used for the analyses on TNFi categories; missing data were imputed as low TNFi category.ResultsOf 129 TNFi-treated patients, 88 were randomised to tapering and 41 to a control arm with standard care. Blood samples at baseline and month 18 were available for: tapering group 89% (78/88) and control group 90% (37/41). As expected, baseline TNFi categories were comparable between groups as presented in Figure 1. At 18 months, fewer patients in the tapering group were in the high TNFi category, relative risk: RR: 0.53 (95%CI 0.31 to 0.90, P=0.02), Table 1. Even though more patients in the tapering group were in the low TNFi category at 18 months, the difference was non-significant, RR: 1.47 (95%CI: 0.94 to 2.32, P=0.09). The observed changes in TNFi categories between groups from baseline to 18 months indicates acceptable compliance to the trial interventions. At 18 months, 32% (28/88) in the tapering group and 0% (0/41) in the control group had achieved ≥50% dose reduction of their TNFi and were in LDA. The majority of patients in the tapering group were in the high (39% [11/28]) or intermediate (39% [11/28]) TNFi category at baseline; only 22% (6/28) were in the low TNFi category. Thus, indicating a greater chance of successful tapering for patients with high or intermediate TNFi drug levels at baseline.ConclusionSuccessful TNFi tapering was associated with high or intermediate TNFi levels at baseline. Fewer patients in the tapering group were in the high TNFi category at 18 months; thus, indicating acceptable compliance to the trial interventions. Further research is needed for the implications of therapeutic drug monitoring in the management of rheumatic diseases.Reference[1]Uhrenholt L, Christensen R, Dreyer L et al. Disease activity-guided tapering of biologics in patients with inflammatory arthritis: A pragmatic, randomised, open-label, equivalence trial. Scand J Rheumatol 2023 (Accepted for publication)Table 1.TNFi drug level categories at 18 months.Variable18 monthsTapering group N=88Control group N=41Between group difference RR (95%CI)TNFi drug level category:High, n (%)19 (22%)17 (42%)0.53 (0.31 to 0.90)Intermediate, n (%)25 (28%)10 (24%)1.12 (0.60 to 2.09)Low, n (%)44 (50%)14 (34%)1.47 (0.94 to 2.32)N: number, RR: relative risk, 95%CI: 95% confidence interval, TNFI: tumour-necrosis factor inhibitor.AcknowledgementsThe authors thank patients and research personnel who contributed to the BIODOPT trial.Disclosure of InterestsMads Sørensen: None declared, Salome Kristensen: None declared, Karen Buch Lauridsen Speakers bureau: Thermo Fisher Scientific, Kirsten Duch: None declared, Lene Dreyer Speakers bureau: Eli Lilly, Galderma, and Janssen, Grant/research support from: BMS (outside the present work), Robin Christensen: None declared, Ellen-Margrethe Hauge Speakers bureau: AbbVie, Sanofi, Sobi, and SynACT Pharma, Grant/research support from: Aarhus University Hospital from Danish Regions Medicine Grants, Danish Rheumatism Association, Roche, Novartis, and Novo Nordic Foundation, Anne Gitte Loft Speakers bureau: AbbVie, MSD, Novartis and UCB, Consultant of: Eli-Lilly, Janssen-Cilag, MSD, Novartis, and UCB, Mads Nyhuus Bendix Rasch Speakers bureau: Sobi, Hans Christian Horn: None declared, Peter C. Taylor Consultant of: AbbVie, Biogen, Eli-Lilly, Fresenius, Galapagos, Gilead Sciences, GlaxoSmithKline, Janssen, Nordic Pharma, Pfizer Inc, Roche, and Sanofi, Grant/research support from: Galapagos, Kaspar René Nielsen: None declared, Line Uhrenholt Speakers bureau: AbbVie, Eli-Lilly, Janssen, and Novarti.s.

Nowadays, small vertical axis wind turbines are receiving more attention due to their suitability in micro-electricity generation. There are few vertical axis wind turbine designs with good power curve. However, the efficiency of power extraction has not been improved. Therefore, an attempt has been made to utilize high lift technology for vertical axis wind turbines in order to improve power efficiency. High lift is obtained by double-element airfoil mainly used in aeroplane wing design. In this current work a low Reynolds number airfoil is selected to design a double-element airfoil blade for use in vertical axis wind turbine to improve the power efficiency. Double-element airfoil blade design consists of a main airfoil and a slat airfoil. Orientation of slat airfoil is a parameter of investigation in this paper and air flow simulation over double-element airfoil. With primary wind tunnel test an orientation parameter for the slat airfoil is initially obtained. Further a computational fluid dynamics (CFD) has been used to obtain the aerodynamic characteristics of double-element airfoil. The CFD simulations were carried out using ANSYS CFX software. It is observed that there is an increase in the lift coefficient by 26% for single-element airfoil at analysed conditions. The CFD simulation results were validated with wind tunnel tests. It is also observe that by selecting proper airfoil configuration and blade sizes an increase in lift coefficient can further be achieved.

The global trade in nonhuman primates represents a substantial threat to ecosystem health, human health, and primate conservation worldwide. Most of the primate trade involves trade for pet-keeping, consumption, or biomedical experimentation. We present an overview of international primate trade through five case studies; each describes a different facet of this trade. We draw on published scientific literature, media outlets, and open access datasets, including the CITES Trade Database to build these case studies. Case study 1 describes the role of introduced island populations of Macaca and Chlorocebus in trade for biomedical experimentation; case study 2 covers the global health threats posed by the primate trade, including zoonotic disease transmission once animals enter the trade pipeline; case study 3 addresses the ways that changing patterns of primate trade, from local markets to online, have increased the demand for primates as pets; case study 4 recognizes the role that local environmental activism can play in mitigating trade; and case study 5 shows variation between global regions in their contribution to the primate trade. We recommend greater oversight of primate trade, especially domestic trade within primate range countries, and real-time reporting to CITES to accurately track primate trade. Effective conservation-focused regulations that can minimise the negative effects of primate trade must be tailored to specific regions and species and require transparency, careful regulation, field research, and an understanding of the magnitude of this trade.

Epidemiologic studies report associations between particulate air pollution and cardiopulmonary morbidity and mortality. Although the underlying pathophysiologic mechanisms remain unclear, it has been hypothesized that altered autonomic function and pulmonary/systemic inflammation may play a role. In this study we explored the effects of air pollution on autonomic function measured by changes in heart rate variability (HRV) and blood markers of inflammation in a panel of 88 elderly subjects from three communities along the Wasatch Front in Utah. Subjects participated in multiple sessions of 24-hr ambulatory electrocardiographic monitoring and blood tests. Regression analysis was used to evaluate associations between fine particulate matter [aerodynamic diameter ≤ 2.5 μm ( PM2.5)] and HRV, C-reactive protein (CRP), blood cell counts, and whole blood viscosity. A 100-μ g/ m3increase in PM2.5was associated with approximately a 35 (SE = 8)-msec decline in standard deviation of all normal R-R intervals (SDNN, a measure of overall HRV); a 42 (SE = 11)-msec decline in square root of the mean of the squared differences between adjacent normal R-R intervals (r-MSSD, an estimate of short-term components of HRV); and a 0.81 (SE = 0.17)-mg/dL increase in CRP. The PM2.5- HRV associations were reasonably consistent and statistically robust, but the CRP association dropped to 0.19 (SE = 0.10) after excluding the most influential subject. PM2.5was not significantly associated with white or red blood cell counts, platelets, or whole-blood viscosity. Most short-term variability in temporal deviations of HRV and CRP was not explained by PM2.5; however, the small statistically significant associations that were observed suggest that exposure to PM2.5may be one of multiple factors that influence HRV and CRP.

As a variation of the pseudodynamic testing technique, the real-time hybrid simulation (RTHS) technique is executed in real time, thus allowing investigation of structural systems with rate-dependent components. In this paper, the RTHS is employed for performance evaluation of full-scale liquid sloshing dampers in multi-megawatt wind turbines, where the tuned liquid damper (TLD) is manufactured and tested as the physical substructure while the wind turbine is treated as the numerical substructure and modelled in the computer using a 13-degree-of-freedom (13-DOF) aeroelastic model. Wind turbines with 2 MW and 3 MW capacities have been considered under various turbulent wind conditions. Extensive parametric studies have been performed on the TLD, e.g., various tuning ratios by changing the water level, TLD without and with damping screens (various mesh sizes of the screen considered), and TLD with flat and sloped bottoms. The present study provides useful guidelines for employing sloshing dampers in large wind turbines, and indicates huge potentials of applying RTHS technique in the area of wind energy.

The optimal tuning and effect in terms of modal damping of a viscous damper mounted near the end of a shallow cable are investigated. The damping properties of free vibrations are extracted from the complex wavenumber. The full solution for the lower modes is evaluated numerically, and an explicit and rather accurate analytical approximation is obtained, generalizing recent results for a taut cable. It is found that the effect of the damper on the nearly antisymmetric modes is independent of the sag and the stiffness parameter. In contrast, the nearly symmetric modes develop regions of reduced motion near the ends, with increasing cable stiffness, and this reduces the effect of the viscous damper. Explicit results are obtained for the modal damping ratio and for optimal tuning of the damper.