Undersea fiber optic cable communications system of the future: Operational, reliability, and systems considerations

The systems and operational requirements, reliability, and cost estimates for several undersea fiber optic cable communications systems of varying capacities, data transmission rates, and link distances are analyzed in detail to highlight relevant design tradeoff parameters. It is shown that systems with a high data rate per fiber are more economical and reliable than low data rate systems with multiple fibers. This study concludes that undersea optic cable systems can soon provide reliable broad-band digital services.     

Wind velocity directional fluctuation prediction model

A two-dimensional analytical model of wind directional fluctuation exceedence rates is presented. The model assumes that wind directional fluctuations are binormally distributed. The model correctly predicts the trends but tends to underestimate the exceedence rates. Improvements by making the model three-dimensional are outlined.     

A novel beam-down,gravity-fed,solar thermochemical receiver/reactor for direct solid particle decomposition: Design,modeling, and experimentation

A novel solar-thermochemical reactor for the reduction of ZnO powder using concentrated sunlight has been designed, constructed and tested. The purpose of the reactor is to accomplish the first step in a two-step water-splitting process to generate hydrogen renewably from sunlight using the ZnO redox cycle. Abbreviated as GRAFSTRR (Gravity-Fed Solar-Thermochemical Receiver/Reactor), the reactor is closed to the atmosphere, and features an inverted conical-shaped reaction surface along which reactant powder descends continuously as a moving bed, undergoing a thermochemical reaction at high temperature upon exposure to highly concentrated sunlight within the reaction cavity. Heat transfer and Zn production within the cavity have been modeled, as well as the influence of effective reactant particle size on reactive surface area. Initial experiments using a high-flux solar simulator successfully demonstrated the mechanical stability of the reactor and primary systems, namely particle entrainment in the vortex flow, moving bed adhesion to the reaction surface, and the solid particle delivery and exit mechanism. This paper presents the GRAFSTRR concept, select design choices, and a summary of pertinent findings from experimental and numerical investigations.     

On the implementation of large period piece-wise linear Arnold cat map

Multimedia Tools and Applications - This paper presents a piece-wise linear cat map (PWLCM) obtained by perturbing the conventional quantized Arnold cat map (QACM) with a nonlinear term. The effect...     

Raman amplification at 1.118 ?m in single-mode fibre and its limitation by Brillouin scattering

A forward Raman gain of 2.9 dB has been measured in a 1.1 km low-loss fibre using an LED at 1.118 ?m as a signal source and a CW Nd: YAG laser as a pump. Backward Brillouin scattering, which depletes the pump power towards the end of the fibre, is found to enhance the Raman gain at the front end.     

Collisional narrowing in the optically pumped CH3OH and CH3F lasers

The gain linewidth of the optically pumped CH3F laser is observed to narrow and rebroaden with the addition of He. In addition, we observe the same effect in the CH3OH laser with the addition of the polyatomic buffer gases SF6and CS2. These results offer conclusive evidence of the Dicke narrowing phenomena in these inverted pure rotational transitions. The effect is observed using a high harmonic mixing technique in a Schottky barrier diode.     

Integralrechnung und Computeralgebra

Zusammenfassung  In diesem Artikel wird die historische Entwicklung der Fl?chen- und Volumenmessung beschrieben, die zum heutigen Integralbegriff führte.     

Horse plasma gelsolin labelled with fluorescein isothiocyanate responds to calcium and actin

Reaction between horse plasma gelsolin and fluorescein-5-isothiocyanate (FITC) resulted in incorporation of 4.8 +/- 0.6 fluorescein groups/gelsolin molecule. The sites of modification were not clustered in any one portion of the gelsolin polypeptide chain; all major peptides produced by proteolytic digestion with alpha-chymotrypsin exhibited a fluorescence characteristic of fluorescein. FITC-gelsolin has a peptide-backbone circular dichroism spectrum at 20 degrees C that is indistinguishable from that of native gelsolin, but FITC-gelsolin is considerably more resistant than native gelsolin to thermally induced precipitation. FITC-gelsolin is fully able to carry out severing of F-actin filaments, the prime function of gelsolin in plasma. An opening up of the structure of gelsolin on binding Ca2+ is evident from an increased susceptibility of FITC-gelsolin to quenching by I-. Ca2+ dependence of the interaction between gelsolin and actin is evident in titrations both of intensity and polarization of the fluorescence of FITC-gelsolin solutions. A Ca(2+)-sensitive interaction between gelsolin and tropomyosin also is observed.