Test results from a dynamic model dynaflex rotor

A one-fifth scale dynamic model of the Sikorsky Dynaflex rotor was tested in hover and in forward flight conditions in a wind tunnel. The Dynaflex rotor features an advanced composite structure which flexes to provide a constant speed universal joint action. Testing concentrated on confirming that the stability and dynamic response of the rotor were satisfactory. Lift conditions of up to .11 Ct/sigma and advance ratios as high as .46 were reached. Vibratory loads were compared to those of articulated rotors. The Dynaflex rotor concept appears to be a practical concept from the standpoint of dynamic response and stability

Mental Health of Children and Young People in England, 2017: Trends and characteristics

This survey series provides England’s best source of data on trends in child mental health. Emotional, behavioural, hyperactivity, and other types of mental disorder were assessed in 5 to 15 year olds in 1999, 5 to 16 year olds in 2004, and 5 to 19 year olds in 2017. One in eight (12.8%) 5 to 19 year olds had a mental disorder when assessed in 2017. Rates were similar in boys and girls. Data for 5 to 15 year olds show a slight upward trend over time in the prevalence of emotional disorders.Rates for behavioural, hyperactivity and other disorders have remained broadly stable

Small-noise analysis and symmetrization of implicit Monte Carlo samplers

Implicit samplers are algorithms for producing independent, weighted samples from multi-variate probability distributions. These are often applied in Bayesian data assimilation algorithms. We use Laplace asymptotic expansions to analyze two implicit samplers in the small noise regime. Our analysis suggests a symmetrization of the algo- rithms that leads to improved (implicit) sampling schemes at a rel- atively small additional cost. Computational experiments confirm the theory and show that symmetrization is effective for small noise sampling problems

Hospital and Physician Capacity Update

Offers an alternative view of healthcare costs by examining trends in hospital capacity and healthcare labor across regions. Outlines how effective management of healthcare capacity would enable affordable quality care that meets patient needs and wants

Grazing-angle scattering of electromagnetic waves in gratings with varying mean parameters: grating eigenmodes

A highly unusual pattern of strong multiple resonances for bulk electromagnetic waves is predicted and analysed numerically in thick periodic holographic gratings in a slab with the mean permittivity that is larger than that of the surrounding media. This pattern is shown to exist in the geometry of grazing-angle scattering (GAS), that is when the scattered wave (+1 diffracted order) in the slab propagates almost parallel to the slab (grating) boundaries. The predicted resonances are demonstrated to be unrelated to resonant generation of the conventional guided modes of the slab. Their physical explanation is associated with resonant generation of a completely new type of eigenmodes in a thick slab with a periodic grating. These new slab eigenmodes are generically related to the grating; they do not exist if the grating amplitude is zero. The field structure of these eigenmodes and their dependence on structural and wave parameters is analysed. The results are extended to the case of GAS of guided modes in a slab with a periodic groove array of small corrugation amplitude and small variations in the mean thickness of the slab at the array boundaries.Comment: 16 pages, 6 figure

Pairing transition of nuclei at finite temperature

Pairing transition at finite temperature was investigated by the shell model and BCS calculations. The definitive signature of pairing transition is identified by a "transition temperature" $T_t$ estimated from a "thermal" odd-even mass difference, while there is no sharp phase transition because of the finiteness of nucleus. It is found that $T_t$ is in good agreement with predictions of critical temperature $T_c$ in the BCS approximation, and the pairing correlations almost vanish at two points of the transition temperature $T\approx 2T_{t}$. The BCS calculations show that the critical temperature $T_c$ increases with increasing deformation.Comment: 12 pages, 6 figures, accepted for publication in Nuclear Physics

Evaluation of effectiveness of various devices for attenuation of trailing vortices based on model tests in a large towing basin

The effectiveness of various candidate aircraft-wing devices for attenuation of trailing vortices generated by large aircraft is evaluated on basis of results of experiments conducted with a 0.03-scale model of a Boeing 747 transport aircraft using a technique developed at the HYDRONAUTICS Ship Model Basin. Emphasis is on the effects produced by these devices in the far-field (up to 8 kilometers downstream of full-scale generating aircraft) where the unaltered vortex-wakes could still be hazardous to small following aircraft. The evaluation is based primarily on quantitative measurements of the respective vortex velocity distributions made by means of hot-film probe traverses in a transverse plane at selected stations downstream. The effects of these altered wakes on rolling moment induced on a small following aircraft are also studied using a modified lifting-surface theory with a synthesized Gates Learjet as a typical example. Lift and drag measurements concurrently obtained in the model tests are used to appraise the effects of each device investigated on the performance characteristics of the generating aircraft

The measurement of rock deformability in bore holes on earth. Adaptability to a lunar exploration program

Dilatometers, bore hole jacks, and penetrometers, for measurement of rock deformability in bore holes on eart

Ice in the Antarctic polar stratosphere

On six occasions during the 1987 Airborne Antarctic Ozone Experiment, the Polar Stratospheric Cloud (PSC) ice crystals were replicated over the Palmer Peninsula at approximately 70 deg South. The sampling altitude was approximately 60 to 65 thousand feet, the temperature range was -83.5 to -72C and the atmosphere was subsaturated in all cases. The collected crystals were predominantly complete and hollow prismatic columns with maximum dimensions up to 217 microns. Evidence of scavenging of submicron particles was detected on several crystals. While the replicated crystal sizes were larger than anticipated, their relatively low concentration results in a total surface area less than one tenth that of the sampled aerosol particles. The presence of large crystals suggest that PSC ice crystals can play a very important role in stratospheric dehydration processes