Antireflection coated, wedged, single-crystal silicon aircraftwindow for the far-infrared

Operating far-infrared remote-sensing instruments from inside a pressurized cabin of an aircraft requires a window with high transmittance. Furthermore, the radiometric properties of the window, such as the transmittance and the emitted radiation (i.e., temperature distribution), have to be known. The design of a wedged, antireflection coated single-crystal silicon aircraft window, its modeled transmittance spectrum, and the applied coating technique are presented. Measurements of the window transmittance with the 2.5 THz heterodyne spectrometer TeraHertz OH-Measurement Airborne Sounder (THOMAS) and a Fourier-transform spectrometer are presented, showing a transmittance of about 90% around 84 cm^-1. The window was designed and built for the 2.5 THz OH-Sensor THOMAS, operated on the DLR research aircraft FALCON. The transmittance of 90% means a substantial improvement compared to the window used previously. With this new window, systematic errors in the measured atmospheric radiance could be lowered, making the retrieval of atmospheric parameters easier. Several successful flights with the new window up to an altitude of 43000 ft have already been performed     

Weld line transverse energy density distribution measurement in laser transmission welding of thermoplastics

While laser beam profiling techniques are available for the measurement of a laser beam power profile, such techniques are difficult or impossible to use in order to characterize the power profile of the beam which has passed through the light-scattering semi-crystalline polymer (such as nylon). This paper presents a technique for measuring the scattering of the laser beam caused by the laser-transparent part in laser transmission welding. The technique is easy to implement and does not require specialized or expensive equipment. It relies on measurements of line widths for a sequence of lines left on the polymer surface by a rapidly moving laser beam at progressively increasing powers. The line width and power information is then used to obtain the distribution of the laser energy across the weld line. An application for a case of a high-power diode laser and (glass-reinforced and natural) polyamide 6 is presented.     

Physical modeling and control of dynamic foaming in an LD-converterprocess

This paper deals with physical modeling and control of dynamic foaming in the LD-converter process. An experimental setup consisting of a water model, digital signal processor, and PC hardware is built and shown to be useful for studying dynamic foaming. Furthermore, a foam height estimation algorithm is presented and validated through experiments. Finally, sound signals from the LD-converter and water model are compared and similarities between them are found     

AN EXPERIMENTAL INVESTIGATION OF A CYLINDRICAL VESSEL ENGULFED IN FIRE WITH A BURNING RELIEF VALVE FLARE PRESENT

Tests were performed with a 0.6 m diameter, 1.8 m long cylindrical vessel exposed to an engulfing JP4 fueled pool fire (2.5 m diameter pool) and a propane fueled simulated relief valve flare which emanated from the tank top-centre. The tank was partially filled with water and was instrumented with thermocouples and heat flux transducers. Thermocouples were also externally situated to measure fire temperatures, The tests were conducted indoors and were therefore isolated from cross winds.

Tests were conducted involving only the burning relief valve flare and with both the burning flare and pool fire. Data recorded during the tests included vessel wall temperatures, heat fluxes to the vessel, lading temperatures, and fire temperatures.

Results from the tests indicate that in the absence of cross wind effects, the burning relief valve flare had no significant effect on the vessel when it was already engulfed in fire. The very sooty fire acted as a shield between the flare and the vessel. However, the high momentum flare resulted in a significant change in the geometry of the burning pool fire and this in turn could affect the heat flux to remote targets

Results are presented which show the response of the vessel and its lading to the different fire conditions. Comparisons are made between the results obtained here and those obtained from previously conducted tests involving full and fifth scale rail tank-cars exposed to engulfing fires     

The costs and benefits of tonal centers for chord processing.

Harmonic priming studies have shown that a musical context, with its established tonal center, influences target chord processing. This study investigated costs and benefits of priming tonal centers for target processing by adding a baseline condition (sequences without a specific tonal center). Results confirmed harmonic priming, with faster processing for related than for unrelated and less related targets (tonic chord, out-of-key chord, subdominant chord). Comparing targets in baseline contexts with targets in sequences with well-established tonal centers revealed a benefit of processing for related targets but a cost of processing for unrelated and less related targets. Findings are discussed in terms of tonal knowledge activation and suggest that an activated tonal center gives rise to strong expectations for the tonic. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance limitation due to statistical Raman crosstalk in a WDM system with multiple-wavelength bidirectionally pumped Raman amplification

A general theoretical model of statistical Raman crosstalk and its impact on system performance in a multiwavelength bidirectionally pumped Raman fiber amplifier (RFA) is developed for the first time, where we have taken modulation statistics, dispersion-induced pulse walk-off and signal-induced pump depletion into account. Two kinds of statistical Raman crosstalk, from signal-induced forward-pump depletion and from signal-signal Raman interaction, are included in one model. Formulas for normalized Raman crosstalk, Raman crosstalk-induced relative intensity noise spectral density, and its variance and system performance impact in terms of Q penalty are presented for both a single-span system and a dispersion-compensated multispan wavelength-division-multiplexed (WDM) link. Based on these formulas, we numerically investigate the impact of Raman crosstalk on system performance in a three-wavelengths bidirectionally pumped 40 /spl times/ 40-Gb/s WDM system for various fiber types. In addition, Raman crosstalk in a four-wavelength bidirectionally pumped RFA was experimentally measured. The results agree well with our theory.     

Soyabean saponins. IX. Studies of their effect on birds, mammals and cold-blooded organisms

The effect of soyabean saponins on the growth of chicks, mice, rats and Tribolium castaneum larvae and on the survival time of tadpoles and guppies was studied. Soyabean saponins did not impair growth of chicks when added at five times the concentration in a normal soyabean-supplemented diet. They had also no effect on the growth response of rats and mice and on the amount of ingested food, but caused slight growth retardation of Tribolium castaneum larvae. Soyabean saponins showed a pronounced detrimental effect on tadpoles and guppies.