Damage measurements on the NWTC direct-drive, Variable-Speed Test Bed

The NWTC (National Wind Technology Center) Variable-Speed Test Bed turbine is a three-bladed, 10-meter, downwind machine that can be run in either fixed-speed or variable-speed mode. In the variable-speed mode, the generator torque is regulated, using a discrete-stepped load bank to maximize the turbine`s power coefficient. At rated power, a second control loop that uses blade pitch to maintain rotor speed essentially as before, i.e., using the load bank to maintain either generator power or (optionally) generator torque. In this paper, the authors will use this turbine to study the effect of variable-speed operation on blade damage. Using time-series data obtained from blade flap and edge strain gauges, the load spectrum for the turbine is developed using rainflow counting techniques. Miner`s rule is then used to determine the damage rates for variable-speed and fixed-speed operation. The results illustrate that the controller algorithm used with this turbine introduces relatively large load cycles into the blade that significantly reduce its service lifetime, while power production is only marginally increased

Pegasus IV: Discovery and Spectroscopic Confirmation of an Ultra-faint Dwarf Galaxy in the Constellation Pegasus

We report the discovery of Pegasus IV, an ultra-faint dwarf galaxy found in archival data from the Dark Energy Camera processed by the DECam Local Volume Exploration Survey. Pegasus IV is a compact, ultra-faint stellar system (r1 2 = 41-+68 pc; MV = −4.25 ± 0.2 mag) located at a heliocentric distance of 90-+64 kpc. Based on spectra of seven nonvariable member stars observed with Magellan/IMACS, we confidently resolve Pegasus IV’s velocity dispersion, measuring sv = 3.3-+1.11.7 km s−1 (after excluding three velocity outliers); this implies a mass-to-light ratio of M1 2 LV,1 2 = 167-+99224M☉ L☉ for the system. From the five stars with the highest signal-to-noise spectra, we also measure a systemic metallicity of [Fe/H] =-2.63-+0.300.26 dex, making Pegasus IV one of the most metal-poor ultra-faint dwarfs. We tentatively resolve a nonzero metallicity dispersion for the system. These measurements provide strong evidence that Pegasus IV is a dark-matter-dominated dwarf galaxy, rather than a star cluster. We measure Pegasus IV’s proper motion using data from Gaia Early Data Release 3, finding (μα*, μδ) = (0.33 ± 0.07, −0.21 ± 0.08) mas yr−1. When combined with our measured systemic velocity, this proper motion suggests that Pegasus IV is on an elliptical, retrograde orbit, and is currently near its orbital apocenter. Lastly, we identify three potential RR Lyrae variable stars within Pegasus IV, including one candidate member located more than 10 half-light radii away from the system’s centroid. The discovery of yet another ultra-faint dwarf galaxy strongly suggests that the census of Milky Way satellites is still incomplete, even within 100 kpc

Arbeitslosigkeit und Stellenannahmebereitschaft: Erste Ergebnisse eines Faktoriellen Survey Moduls

Matching individuals to jobs is a fundamental problem in any labour market. This paper focuses on job characteristics, such as wages, job quality, and distance from the current place of residence, and the impact of these characteristics on the willingness of employed and unemployed individuals to accept new job offers. Using an experimental factorial survey module (FSM) implemented in the fifth wave of a large population survey (Panel Study Labour Market and Social Security), the willingness of employed and unemployed labour market participants to accept new job offers was compared while considering job characteristics like gain of income or commuting distance. In this study, unemployed and employed individuals received the same set of hypothetical job offers. Consistent with theoretical arguments, the about 20,000 evaluations provided by about 4,000 respondents showed that unemployed participants generally exhibit a greater willingness to accept new job offers than employed ones. Moreover, unemployed individuals were likely to make more concessions than employed individuals with respect to job quality, such as accepting fixed-term job offers. Interestingly, little evidence for different decision-making or weightings of mobility costs was found, which enables us to conclude that interregional unemployment disparities can scarcely be explained by unemployed individuals lacking the willingness to work or relocate

Health and wellbeing of Indigenous adolescents in Australia: a systematic synthesis of population data

Indigenous populations have high rates of disease and premature mortality. Most Indigenous communities are young, and adolescence (age 10-24 years) provides great opportunities for population health gain. However, the absence of a comprehensive account of Indigenous adolescents' health has been a barrier to effective policy. We aimed to report a national health profile for Indigenous adolescents in Australia.We undertook a systematic synthesis of population data to report the health and wellbeing of Indigenous adolescents in Australia. A reporting framework for Indigenous adolescent health in Australia was defined to measure health outcomes, health risks, and sociocultural determinants. Available data (primary data from national surveys and administrative datasets, and available published data) were mapped against the defined reporting framework, and the quality graded, with the highest quality data selected to report a health profile for Indigenous adolescents. Comparison with non-Indigenous adolescents was made where possible, and estimates (disaggregated by age, sex, and remoteness) were reported as relative risks. A national advisory group (six Indigenous young people, three Indigenous adult community members, three researchers, three policy makers, and two service providers, all aged ≥16 years) provided input about the reporting framework, interpretation of findings, and policy recommendations.Data were available for 184 (79%) of 234 elements of the reporting framework. All-cause mortality for Indigenous adolescents (70 per 100 000) was more than twice that of non-Indigenous adolescents, with about 60% of deaths due to intentional self-harm and road traffic injury. 80% of all deaths among Indigenous adolescents were considered as potentially avoidable in the current health system. Communicable diseases (particularly sexually transmitted infections) were leading contributors to morbidity. Almost a third of Indigenous adolescents aged 18-24 years reported high levels of psychological distress (twice the non-Indigenous rate). There was an excess burden of mental disorders and substance use, alongside emerging type 2 diabetes and ischaemic heart disease. Additionally, there were excess intentional and unintentional injuries. Many aspects of this health profile differed markedly from that of non-Indigenous adolescents: rates of acute rheumatic fever, pneumococcal infection, gonorrhoea, and type 2 diabetes resulting in admission to hospital were ten times higher; rates of assault and childbirth in those aged 15-19 years were five times higher; whereas rates of eating disorders, melanoma and other skin cancers, and anaphylaxis were significantly lower. Risks for future ill-health were common; 43% of 15-24 year olds were current tobacco smokers and about 45% had high body mass (overweight or obese). Disadvantage across sociocultural health determinants also emerged, particularly around education.Despite Australia's adolescents having one of the best health profiles globally, Indigenous adolescents have largely been left behind. Adequate responses will require intersectoral actions, including a health system responsive to the needs of Indigenous adolescents. Without a specific focus on adolescents, Australia will not redress Indigenous health inequalities.Australia's National Health and Medical Research Council, Sidney Myer Foundation, and the Murdoch Children's Research Institute.Peter S Azzopardi, Susan M Sawyer, John B Carlin, Louisa Degenhardt, Ngiare Brown, Alex D Brown, George C Patto