Aerodynamics of the Cupped Wings during Peregrine Falcon’s Diving Flight

During a dive peregrine falcons can reach velocities of more than 320 km/h and makes themselves the fastest animals in the world. The aerodynamic mechanisms involved are not fully understood yet and the search for a conclusive answer to this fact motivates the three-dimensional (3-D) flow study. Especially the cupped wing configuration which is a unique feature of the wing shape in falcon peregrine dive is our focus herein. In particular, the flow in the gap between the main body and the cupped wing is studied to understand how this flow interacts with the body and to what extend it affects the integral forces of lift and drag. Characteristic shapes of the wings while divingare studied with regard to their aerodynamics using computational fluid dynamics (CFD). The results of the numerical simulations via ICEM CFD and OpenFOAM show predominant flow structures around the body surface and in the wake of the falcon model such as a pair of body vortices and tip vortices. The drag for the cupped wing profile is reduced in relation to the configuration of opened wings (without cupped-like profile) while lift is increased. The purpose of this study is primarily the basic research of the aerodynamic mechanisms during the falcon’s diving flight. The results could be important for maintaining good maneuverability at high speeds in the aviation sector

Feather Vibration as a Stimulus for Sensing Incipient Separation in Falcon Diving Flight

Based on our preceding studies on the aerodynamics of a falcoperegrinus in diving flight along a vertical dam it is known that even when the body shape of the bird is rather streamlined in V-shape some feathers tips may elevate in certain regions of the body. These regions were identified in wind tunnel tests for typical diving flight conditions as regions of locally separated flow. A life-size model in V-shape of a falcoperegrinus with artificial feathers fixed along the body was studied in a wind tunnel to focus on the fluid-structure interaction of feathers located in this sector. The distal ends of the feathers show flow-induced vibrations at typical flight conditions which grow linear in amplitude with increasing angle of incidence until incipient separation. In light of the proven existence of vibration-sensitive mechanoreceptors in the follicles of secondary feathers in birds it is hypothesized that this linear amplitude response offers the bird to sense the angle of incidence during the diving flight using the vibration magnitude as sensory stimulus. Thus the bird in streamlined shape has still a good measure to control its attitude to be in the narrow window of safe angle of incidence. This might have implications also for other birds or technical applications of airfoil sensors regarding incipient separation detection

Investigation of the washout effect in a magnetically driven axial blood pump

For a long-term implementation of the magnetically driven CircuLite blood pump system, it is extremely important to be able to ensure a minimum washout flow in order to avoid dangerous stagnation regions in the gap between the impeller and the motor casing as well as near the pivot-axle area at the holes in the impeller's hub. In general, stagnation zones are prone to thrombus formation. Here, the optimal impeller/motor gap width will be determined and the washout flow for different working conditions will be quantitatively calculated. The driving force for this secondary flow is mainly the strong pressure difference between both ends of the gap. Computational fluid dynamics (CFD) and digital particle image velocimetry (DPIV) will be used for this analysis

El terremoto del último 7 de septiembre : tiembla, todo tiembla

Fil: Folguera, Andrés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Tectónica Andina; Argentina.Fil: Triep, Enrique. Instituto de Sismología Volponi; Argentina.Fil: González Díaz, Emilio M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil: Ramos, Víctor A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Tectónica Andina; Argentina.Los terremotos no son un fenómeno del pasado y las placas que conforman los niveles móviles más\nsuperficiales de la Tierra están aún en pleno movimiento. Con respecto a la intensidad de los mismos y\nsus desplazamientos asociados, la actividad actual, en especial la deformación permanente asociada\na estos terremotos, se ha mantenido en el mismo orden de magnitud que en los últimos 10 millones de\naños. La frecuencia con la que ocurren estos movimientos está también dentro del mismo orden,\nsiendo quizás la diferencia más significativa el avance de la tecnología y las comunicaciones de este\nmundo global que nos permiten conocer al instante este tipo de eventos en cualquier parte del planeta,\npareciendo de esta forma un fenómeno más periódico en la actualidad

Semi-Automated Approach to Retrieve SNOMED CT Hierarchy of Clinical Terms by Using Terminology Server.

SNOMED CT has an enormous number of clinical concepts and mapping to SNOMED CT is considered as the foundation to achieve semantic interoperability in healthcare. Manual mapping is time-consuming and error-prone thus making this crucial step challenging. In addition, hierarchy retrieval of clinical concepts increases the challenges for the user. Terminology Servers provide an interface, which can be used to automate the process of retrieving data. In this work, it is shown that Snowstorm can significantly improve the efficiency of retrieval process if used with semi-automated workflows

State Educational Insurance as a Basis for Continuous Wellbeing of a Man and Society

At the present stage of development of the Russian state its primary objective is to provide citizens with access to fully-fledged quality education conforming to their interests and abilities regardless of their material wealth, place of residence, nationality and health. The goal can be achieved if to develop state educational insurance. Establishment of the system of state educational insurance is possible if the process of shaping individuals' knowledge, skills and abilities (competences) is improved. The result of the system operation is the process of capitalization aimed at ensuring continuous well-being of individuals, households, organizations and country in general. Capitalization of knowledge, skills, and abilities (competences) generates individuals' financial interest associated with their education, i.e. interest in receiving education as a source of their future income. Financial interest, the subject of which is a man's accomplishment, enables studying opportunities for establishing intercourse on ensuring individuals' income, resulting from his accomplishment. This process, in its turn, initiates insurance of an individual's rights and guarantees in the field of education. On the one hand, regular insurance financing of educational system, ensures its stability for future generations of the Russian society. On the other hand, it will establish the basis for sustainable creation of workforce

Semi-Automated Approach to Map Clinical Concepts to SNOMED CT Terms by Using Terminology Server.

SNOMED CT has an enormous number of clinical concepts and mapping to SNOMED CT is considered as the foundation to achieve semantic interoperability in healthcare. Manual mapping is time-consuming and error-prone thus making this crucial step challenging. Terminology Servers provide an interface, which can be used to automate the process of retrieving data. Snowstorm is a terminology server developed by SNOMED International. In this work, the feasibility of using Snowstorm to automate the data retrieval and mapping has been discussed

A Canonical Biomechanical Vocal Fold Model

The present article aimed at constructing a canonical geometry of the human vocal fold (VF) from subject-specific image slice data. A computer-aided design approach automated the model construction. A subject-specific geometry available in literature, three abstractions (which successively diminished in geometric detail) derived from it, and a widely used quasi two-dimensional VF model geometry were used to create computational models. The first three natural frequencies of the models were used to characterize their mechanical response. These frequencies were determined for a representative range of tissue biomechanical properties, accounting for underlying VF histology. Compared with the subject-specific geometry model (baseline), a higher degree of abstraction was found to always correspond to a larger deviation in model frequency (up to 50% in the relevant range of tissue biomechanical properties). The model we deemed canonical was optimally abstracted, in that it significantly simplified the VF geometry compared with the baseline geometry but can be recalibrated in a consistent manner to match the baseline response. Models providing only a marginally higher degree of abstraction were found to have significant deviation in predicted frequency response. The quasi two-dimensional model presented an extreme situation: it could not be recalibrated for its frequency response to match the subject-specific model. This deficiency was attributed to complex support conditions at anterior-posterior extremities of the VFs, accentuated by further issues introduced through the tissue biomechanical properties. In creating canonical models by leveraging advances in clinical imaging techniques, the automated design procedure makes VF modeling based on subject-specific geometry more realizable

3D flow in the venom channel of a spitting cobra: do the ridges in the fangs act as fluid guide vanes?

The spitting cobra Naja pallida can eject its venom towards an offender from a distance of up to two meters. The aim of this study was to understand the mechanisms responsible for the relatively large distance covered by the venom jet although the venom channel is only of micro-scale. Therefore, we analysed factors that influence secondary flow and pressure drop in the venom channel, which include the physical-chemical properties of venom liquid and the morphology of the venom channel. The cobra venom showed shear-reducing properties and the venom channel had paired ridges that span from the last third of the channel to its distal end, terminating laterally and in close proximity to the discharge orifice. To analyze the functional significance of these ridges we generated a numerical and an experimental model of the venom channel. Computational fluid dynamics (CFD) and Particle-Image Velocimetry (PIV) revealed that the paired interior ridges shape the flow structure upstream of the sharp 90° bend at the distal end. The occurrence of secondary flow structures resembling Dean-type vortical structures in the venom channel can be observed, which induce additional pressure loss. Comparing a venom channel featuring ridges with an identical channel featuring no ridges, one can observe a reduction of pressure loss of about 30%. Therefore it is concluded that the function of the ridges is similar to guide vanes used by engineers to reduce pressure loss in curved flow channels