The poetry of Theophile De Viau with special reference to his themes and images

Not availabl

Absolute differential cross sections for electron-impact excitation of CO near threshold: II. The Rydberg states of CO

Absolute differential cross sections for electron-impact excitation of Rydberg states of CO have been measured from threshold to 3.7 eV above threshold and for scattering angles between 20° and 140°. Measured excitation functions for the b 3Σ+, B 1Σ+ and E 1π states are compared with cross sections calculated by the Schwinger multichannel method. The behaviour of the excitation functions for these states and for the j 3Σ+ and C 1Σ+ states is analysed in terms of negative-ion states. One of these resonances has not been previously reported

First experimental observation of the aquatic propulsion caused by localised flexural waves in immersed structures

The present paper reports the results of the first experimental observation of the wave-like aquatic propulsion suitable for man-inhabited marine vessels. The idea of this propulsion, first published by one of the present authors (V.V.K.) more than 10 years ago, is based on employing localised flexural elastic waves propagating along edges of wedge-like elastic structures. Such wave-supporting structures can be attached to a body of a small ship or a submarine as keels or wings and used for the propulsion. To verify the idea experimentally, the first working prototype of a small catamaran using the above-mentioned wave-like propulsion via the attached rubber keel has been build and tested. The test results have shown that the catamaran was propelled quite efficiently and could achieve the speed of about 36 cm/s, i.e. approximately one length of the vessel per second. The reported proof of the viability of the idea of wave-like propulsion as alternative to a propeller may open new opportunities for marine propulsion which can have far reaching implications

Experimental confirmation of the propulsion of marine vessels employing guided flexural waves in attached elastic fins

This paper describes the results of the first experimental verification of the idea of wave-like aquatic propulsion of manned marine vessels first published by one of the present authors (V.V.K.) in 1994. The idea is based on employing the unique type of guided flexural elastic waves propagating along edges of immersed wedge-like structures attached to a body of a small ship or a submarine as keels or wings and used for the propulsion. The principle of employing such guided flexural waves as a source of aquatic propulsion is similar to that used in nature by stingrays. It is vitally important for the application of this idea to manned vessels that, in spite of vibration of the fins, the main body of the craft remains undisturbed as the energy of guided elastic waves is concentrated away from it. The main expected advantages of this new propulsion method over the existing ones, e.g. jets and propellers, are the following: it is quiet, and it is environmentally friendly and safe for people and wildlife. T

Experimental investigation of the aquatic propulsion caused by localised flexural wave propagation in immersed wedges and plates

Experimental investigation of the aquatic propulsion caused by localised flexural wave propagation in immersed wedges and plate

An inexpensive and rapid technique for obtaining current profiles in estuarine waters

A current indicator, consisting of a confined submerged biplane-shaped drag and a device for reading the angle made by the suspending wire with t he vertical, is introduced in t heory and practice. It was designed for rapid determination of current velocities and directions at any depth from a vessel an chored in shallow water. A number of calibration runs made with t he Drag and with a von Arx Current Meter indicate that the Drag is reliable and suffi ciently accurate for the purpose for wluch it was designed. The gear proved to be rugged, easy to use, and inexpensive. It requires little time to make a number of observations from the surface down to 50 feet

Coreless vortex formation in a spinor Bose-Einstein condensate

Coreless vortices were phase-imprinted in a spinor Bose-Einstein condensate. The three-component order parameter of F=1 sodium condensates held in a Ioffe-Pritchard magnetic trap was manipulated by adiabatically reducing the magnetic bias field along the trap axis to zero. This distributed the condensate population across its three spin states and created a spin texture. Each spin state acquired a different phase winding which caused the spin components to separate radially.Comment: 5 pages, 2 figure