In-Plane Vortex-Rotor Interaction and its Implication on Rotor Trim: an Analytic Solution for Arbitrary Vortex Orientation and Position

The general aerodynamic problem of arbitrary oriented in-plane vortex-rotor interaction was investigated in the past only by numerical simulation. Just one special case of in-plane vortex-rotor interaction with the vor-tex axis in flight direction was recently solved analytically. In this paper the analytical solution for arbitrary in-plane vortex orientation and position relative to the rotor on thrust and hub moments is given that was pub-lished for the first time just before. Results provide the vortex impact on rotor trim (thrust, aerodynamic roll-ing and pitching moments about the hub) and the rotor controls required to mitigate these disturbances. In this paper the sensitivity of these results with respect to the main parameters will be given: the vortex core radius, its distance to the rotor center and its orientation angle relative to the rotor longitudinal axis, the rotor blade begin and end of the airfoiled section, and the advance ratio

Paroxysmal mechanical aortic valve prosthesis dysfunction: capturing the right moment

Cardiolog

Influence of blade aerodynamic model on the prediction of helicopter high-frequency airloads

Brown’s vorticity transport model has been used to investigate the influence of the blade aerodynamic model on the accuracy with which the high-frequency airloads associated with helicopter blade–vortex interactions can be predicted. The model yields an accurate representation of the wake structure yet allows significant flexibility in the way that the blade loading can be represented. A simple lifting-line model and a somewhat more sophisticated liftingchord model, based on unsteady thin aerofoil theory, are compared. A marked improvement in the accuracy of the predicted high-frequency airloads of the higher harmonic control aeroacoustic rotor is obtained when the liftingchord model is used instead of the lifting-line approach, and the quality of the prediction is affected less by the computational resolution of the wake. The lifting-line model overpredicts the amplitude of the lift response to blade–vortex interactions as the computational grid is refined, exposing the fundamental deficiencies in this approach when modeling the aerodynamic response of the blade to interactions with vortices that are much smaller than its chord. The airloads that are predicted using the lifting-chord model are relatively insensitive to the resolution of the computation, and there are fundamental reasons to believe that properly converged numerical solutions may be attainable using this approach

Influence of blade aerodynamic model on prediction of helicopter rotor aeroacoustic signatures

Brown’s vorticity transport model has been used to investigate how the local blade aerodynamic model influences the quality of the prediction of the high-frequency airloads associated with blade–vortex interactions, and thus the accuracy with which the acoustic signature of a helicopter rotor can be predicted. The vorticity transport model can accurately resolve the structure of the wake of the rotor and allows significant flexibility in the way that the blade loading can be represented. The Second Higher-Harmonic Control Aeroacoustics Rotor Test was initiated to provide experimental insight into the acoustic signature of a rotor in cases of strong blade–vortex interaction. Predictions of two models for the local blade aerodynamics are compared with the test data. A marked improvement in accuracy of the predicted high-frequency airloads and acoustic signature is obtained when a lifting-chord model for the blade aerodynamics is used instead of a lifting-line-type approach. Errors in the amplitude and phase of the acoustic peaks are reduced, and the quality of the prediction is affected to a lesser extent by the computational resolution of the wake, with the lifting-chord model producing the best representation of the distribution of sound pressure below the rotor

Cardiovascular imaging 2010 in the International Journal of Cardiovascular Imaging

Cardiovascular Aspects of Radiolog

Probing the population of the spin-orbit split levels in the actinide 5f states

Spin-orbit interaction in the 5f states is believed to strongly influence exotic behaviors observed in actinides metals and compounds. Understanding these interactions and how they relate to the actinide series is of considerable importance. To address this issue, the branching ratio of the white-line peaks of the N4,5 edges for the light actinide metals, {alpha}-Th, {alpha}-U, and {alpha}-Pu were recorded using electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) and synchrotron-radiation-based x-ray absorption spectroscopy (XAS). Using the spin-orbit sum rule and the branching ratios from both experimental spectra and many-electron atomic spectral calculations, accurate values of the spin-orbit interaction, and thus the relative occupation of the j = 5/2 and 7/2 levels, are determined for the actinide 5f states. Results show that the spin-orbit sum rule works very well with both EELS and XAS spectra, needing little or no correction. This is important, since the high spatial resolution of a TEM can be used to overcome the problems of single crystal growth often encountered with actinide metals, allowing acquisition of EELS spectra, and subsequent spin-orbit analysis, from nm-sized regions. The relative occupation numbers obtained by our method have been compared with recent theoretical results and show a good agreement in their trend

Внутриартериальная химиотерапия в комбинированном лечении резектабельного рака желудка с метастазами в печень

В Донецком областном противоопухолевом центре разработан и внедрен способ катетеризации печеночной артерии при паллиативных операциях у больных раком желудка с метастазами в печень. По данному способу пролечено 56 больных резектабельным раком желудка с метастатическим поражением печени, что позволило увеличить продолжительность и улучшить качество жизни больных.У Донецькому обласному протипухлинному центрі розроблено та впроваджено спосіб катетеризації печінкової артерії при паліативних операціях у хворих на рак шлунку з метастазами в печінку. За цим способом проліковано 56 хворих на резектабельний рак шлунку з метастатичним ураженням печінки, що дало змогу збільшити тривалість і поліпшити якість життя хворих.A method of catheterization of hepatic artery at palliative surgery in patients with gastric cancer and metastases to the liver was worked out and introduced at Donetsk Regional Antitumor Center. This method was used in 56 patients with operable cancer of the stomach with metastases to the liver, which allowed increasing the duration and improving the quality of life of the patients

Redefining radiotherapy for early-stage breast cancer with single dose ablative treatment: a study protocol

Contains fulltext : 181789.pdf (publisher's version ) (Open Access

TEMPO2, a new pulsar timing package. I: Overview

Contemporary pulsar timing experiments have reached a sensitivity level where systematic errors introduced by existing analysis procedures are limiting the achievable science. We have developed tempo2, a new pulsar timing package that contains propagation and other relevant effects implemented at the 1ns level of precision (a factor of ~100 more precise than previously obtainable). In contrast with earlier timing packages, tempo2 is compliant with the general relativistic framework of the IAU 1991 and 2000 resolutions and hence uses the International Celestial Reference System, Barycentric Coordinate Time and up-to-date precession, nutation and polar motion models. Tempo2 provides a generic and extensible set of tools to aid in the analysis and visualisation of pulsar timing data. We provide an overview of the timing model, its accuracy and differences relative to earlier work. We also present a new scheme for predictive use of the timing model that removes existing processing artifacts by properly modelling the frequency dependence of pulse phase.Comment: Accepted by MNRA