205 research outputs found
Cliff retreat and sea bed morphology under monochromatic wave forcing: Experimental study
Wave flume experiments have been performed to investigate a sandy cliff recession under monochromatic wave forcing. We varied the wave climate through the wave energy flux F and the surf similarity parameter j. The various processes of the cliff erosion cycle are depicted. The sea bed evolution mostly depends on the surf similarity parameter j. Steep planar (j > 0.7), gentle planar (0.5 < j < 0.7) and bared (j < 0.5) profiles are observed. We observed different bar dynamics, including steady and unsteady self-sustained oscillating states. Then we analyze the role of the eroded material on the cliff recession rate. We show that the cliff recession rate increases with the wave energy flux. Moreover, for a given wave energy flux, it is larger for a gentle planar profile than for a bared profile. However it is similar for both a bared profile and a steep planar profile. The cliff recession rate is not a monotonic function of the cliff height as the type of bottom profile influences the wave energy at the cliff
3D Face Messaging On A Watch
A system and method are disclosed that may send a video-like message to a receiver even when the receiver is offline. The system includes a user smart device incorporating an application, and a receiver smart device incorporating the similar application. The method captures a single 2D image of the userâs face using a camera incorporated in the communication device. The 2D image of the userâs face is then recreated as a 3D model. The message to be sent to a receiver is recorded as an audio message and sent along with the 3D model. At the receiver end the audio message is played back with facial movements of the user that correspond to the speech signals sent by the user. The method is incorporated as an application in a smart-watch. The method offers video-like messaging experience at a low computational cost and requires low bandwidth.
KEYWORDS: voice messaging, smart-watch, low bandwidth, video-like messagin
Sediment processes and ïŹow reversal in the undular tidal bore of the Garonne River (France)
A tidal bore is a series of waves propagating upstream as the tidal flow turns to rising, and the bore front corresponds to the leading edge of the tidal wave in a funnel shaped estuarine zone with macro-tidal conditions. Some field observations were conducted in the tidal bore of the Garonne River on 7 June 2012 in the Arcins channel, a few weeks after a major flood. The tidal bore was a flat undular bore with a Froude number close to unity: Fr1 = 1.02 and 1.19 (morning and afternoon respectively). A key feature of the study was the simultaneous recording of the water elevation, instantaneous velocity components and suspended sediment concentration (SSC) estimates, together with a detailed characterisation of the sediment bed materials. The sediment was some silty material (d50 â 13 ÎŒm) which exhibited some non-Newtonion thixotropic behaviour. The velocity and SSC estimate were recorded simultaneously at high frequency, enabling a quantitative estimate of the suspended sediment flux at the end of the ebb tide and during the early flood tide. The net sediment flux per unit area was directed upstream after the bore, and its magnitude was much larger than that at end of ebb tide. The field observations highlighted a number of unusual features on the morning of 7 June 2012. These included (a) a slight rise in water elevation starting about 70 s prior to the front, (b) a delayed flow reversal about 50 s after the bore front, (c) some large fluctuations in suspended sediment concentration (SSC) about 100 s after the bore front and (d) a transient water elevation lowering about 10 min after the bore front passage. The measurements of water temperature and salinity showed nearly identical results before and after the tidal bore, with no evidence of saline and thermal front during the study
Field Measurements in the tidal bore of the Garonne River after a recent flood
A tidal bore is a natural phenomenon associated with the rising flood tide. Composed of surface waves, it may occur in estuaries and propagate up rivers. The present study was conducted in the Garonne River (France) in the Arcins channel. Using an ADV unit and further recording equipments, experimental data are collected during a flat undular bore with a bore Froude number close to unity. Velocity analysis and sediment characterisation revel a slight rise in water elevation starting about 70 s prior to the front and a flow reversal about 50 s after the bore front. The turbulent transport of suspended sediment is presented in term of mass flux per unit area highlighting a negative (upriver) sediment mass transfer
Effect of current density on overvoltage
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrochemical Engineering, 1922.Includes bibliographical references (leaf 70).by Philip Caplain.B.S
Suivi rhéologique du processus d'agrégation de la protéine tau
International audienceAlzheimer's disease is one of thirty pathology called conformational disease that are characterized by errors folding and assembly of protein. In Alzheimer's disease, tau protein and amyloid beta peptide are responsible of the neuronal degeneration. Understanding these mechanisms and diagnosis are closely linked to the availability of an efficient analytical concept for monitoring ex vivo self-assembly of proteins. To understand the aggregation's mechanism, a microsystem is developed for the detection of protein tau based on the micro-rheological followed by high frequency ultrasonic waves. The sensor used is a TSM (Thickness Shear Mode) resonator operating in shear mode at a fundamental frequency of 5MHz. In contact with the fluid to be characterized, the sensor generate shear waves, which are measured in reflection through instrumentation developed in the laboratory. From the measurement of the complex impedance of quartz with a network analyzer, the extraction of G' (elastic modulus) and G'' (viscous modulus) is possible. Initial results indicate that our sensor can quantify, by viscosity, concentration variations of a peptide sequence of tau protein, and can differentiate, by plasticity, the conformational state. Â </p
Towards a rigorous use of SPEM
International audienceModeling software process is a good way to improve development and thus quality of resulting applications. The OMG proposes the SPEM metamodel to describe software processes. Its concepts are described through class diagrams. Unfortunately, it lacks a formal description of its semantics that makes it hard to use. So, we propose a specialization of SPEM that clarifies it and we use OCL to formally express constraints on it
Etude expérimentale de l'érosion d'un massif de sable cohésif par une houle monochromatique
La plupart des cĂŽtes de la Terre reculent et 80% sont rocheuses. La prĂ©vision du recul des falaises littorales est primordiale afin dâanticiper les risques futurs pour les amĂ©nagements littoraux. Cependant, la comprĂ©hension de ce recul est difficile car de nombreux paramĂštres le contrĂŽlent. Des expĂ©riences en canal Ă houle de petite Ă©chelle ont Ă©tĂ© effectuĂ©es oĂč nous avons mis en place un massif de sable humide soumis Ă lâattaque des vagues par sapement. Le but est de comprendre comment lâeffet des vagues contrĂŽle lâĂ©rosion des falaises. La technique de mesure par ombroscopie a Ă©tĂ© employĂ©e et nous a permis de dĂ©tecter la surface du sable et la surface libre en fonction du temps. Nous avons ainsi analysĂ© lâinfluence du forçage des vagues (F, Ο) (oĂč F est le flux dâĂ©nergie des vagues incidentes au large et Ο est le paramĂštre de similitude de âsurfâ) sur la vitesse de recul de la falaise et sur la profondeur des Ă©vĂšnements dâeffondrement. La vitesse de recul de la falaise augmente linĂ©airement avec le flux dâĂ©nergie F. Les dĂ©bris de falaise Ă©rodĂ©s changent la morphologie du fond, les types de morphologie du fond dĂ©pendent fortement du paramĂštre de similitude de âsurfâ au dĂ©ferlement, ou encore du paramĂštre de Dean Ω. Des profils du fond instationnaires prĂ©sentant une oscillation auto-entretenue de la barre sĂ©dimentaire ont Ă©tĂ© observĂ©s. Nous avons de plus Ă©tudiĂ© lâeffet de la granulomĂ©trie du sable utilisĂ© : pour un sable plus fin, la falaise est plus cohĂ©sive et sâeffondre au cours dâĂ©vĂšnements de plus grande ampleur. Etonnamment, le recul de la falaise est plus important pour du sable fin. Ceci est probablement dĂ» Ă une modification de la morphologie du fond conduisant Ă une dissipation de lâĂ©nergie des vagues moins importante. Le volume de sable injectĂ© dans le systĂšme a finalement Ă©tĂ© quantifiĂ©, la barre sĂ©dimentaire a dâabord Ă©tĂ© prĂ©levĂ©e pĂ©riodiquement et il a Ă©tĂ© observĂ© que la vitesse de recul de la falaise vr est constante. Puis, la hauteur de falaise a Ă©tĂ© modifiĂ©e, le recul des falaises est plus important pour des petites falaises. Il semblerait que lâinstationnaritĂ© dâun profil du fond se dĂ©clenche Ă partir dâun volume seuil de sable Ă©rodĂ©. ABSTRACT : Most of the Earth coasts recedes and 80 % are rocky. Prediction of sea-cliff recession is essential to anticipate future risks for coastal development. However, it is difficult to understand this recession because many parameters control it. In addition, both the space and time scales are too big for the different mechanisms of cliff erosion to be fully analysed. Experiments in a small-scale wave flume were conducted in which a massif made of wet sand is submitted to wave attack. The aim is to understand how cliff erosion is wave-controlled. The technique of shadow graph measurements was used to detect the time evolution of sand and water surfaces. We have analyzed the influence of wave forcing (F, Ο) (where F is the incident offshore wave energy flux and Ο is the surf similarity parameter) on the cliff recession rate and on collapse event size. The cliff recession rate increases linearly with the wave energy flux F. The eroded cliff materials change the bottom morphology ; the types of bottom morphology strongly depend on the surf similarity parameter at the breaker point, or the Dean parameter Ω. Bottom profiles characterized by unsteady self-sustained sandbar oscillation were observed. In addition, we studied how sand granulometry change the system evolution. Finer the sand is, more cohesive is the cliff and bigger are cliff collapses. Contrary to what was expected, cliff recession is more important for a finer sand : this could be due to a more dissipative bottom morphology built by fine sands. The sand volume within the system changes following cliff collapses and a sandbar removal during particular experiments. The cliff recession rate is constant when the sandbar is removed and decreases with cliff height. It seems that the unsteadiness of the bottom profile is activated when the volume of eroded sand exceeds a threshold value
Mythologias dramatĂșrgicas e cĂȘnicas contemporĂąneas: Phaedra's love de Sarah Kane
O artigo apresenta os resultados de uma pesquisa teórico-pråtica sobre a adaptação
do mito de Fedra em PhaedraÂŽs Love de Sarah Kane, e especificamente sobre as formas
dramatĂșrgicas e cĂȘnicas propostas pela escritora britĂąnica na sua releitura do mito
desenvolvido originalmente por EurĂpides e retomado em seguida por SĂȘneca e Racine. A
reflexão se då a partir dos parùmetros estéticos da Contemporaneidade, a partir de uma
reflexĂŁo comparativa sobre o dramĂĄtico e o pĂłs-dramĂĄtico, dentro de uma perspectiva
dramaturgica e cĂȘnica. A adaptação de Sarah Kane evidencia questĂ”es Ă©ticas e estĂ©ticas da
Contemporaneidade que condicionam nossos destinos, como a incomunicabilidade, a
exacerbação da sexualidade, a violĂȘncia social e das relaçÔes humanas, a hipocrisia do poder
religioso, o individualismo e a indiferença pós-moderna. A anålise das estruturas
dramaturgicas e das soluçÔes cĂȘnicas aprofunda a reflexĂŁo sobre a variação do tema trĂĄgico
em função dos sucessivos contextos sociais e históricos. Neste sentido, o artigo aborda
também a evolução da tragédia grega à tragédia romana e clåssica, até a ruptura operada pela
forma pós-dramåtica proposta por Sarah Kane e atualizada na encenação realizada em 2007
na cidade de Ouro Preto por Gilson Motta e Tania Alice
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