Evolution of galaxy cluster scaling from XMM-Newton observation of the galaxy clusters at z ⩾ 0.4

We present here new XMM-Newton observations of 3 relatively cool clusters at z ≈ 0.4, complemented by archival observations of 3 other clusters at similar redshift. We derived the M–T and R–T relations from the hydrostatic equation using an isothermal temperature distribution.     

On the structure and dynamics of the thermosphere

Thermospheric temperature, composition and wind measurements from the Dynamics Explorer satellite (DE-2) are interpreted using a three dimensional, multiconstituent spectral model. The analysis accounts for tides driven by the absorbed solar radiation as well as energy and momentum coupling involving the magnetosphere and lower atmosphere. We discuss phenomena associated with the annual tide, polar circulation, magnetic storms and substorms.     

Temperature comparison between CHAMP radio occultation and TIMED/SABER measurements in the lower stratosphere

Global Positioning System (GPS) receiver on the CHAllenging Mini-satellite Payload (CHAMP) and the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, one of four on board the TIMED satellite, provide middle atmosphere temperature profiles by Radio Occultation (RO) and limb viewing infrared emission measurements, respectively. These temperature profiles retrieved by two different techniques in the stratosphere are compared with each other using more than 1300 correlative profiles in March, September and December 2005. The over-all mean differences averaged over 15 and 35 km are approximately −2 K and standard deviation is less than 3 K. Below 20 km of altitude, relatively small mean temperature differences ∼1 K are observed in wide latitudinal range except for June (during the SABER nighttime observation). In the middle to low latitudes, between 30°S and 30°N, the temperature difference increases with height from ∼0–1 K at 15 km, to ∼−4 K at 35 km of altitude. Large temperature differences about −4 to −6 K are observed between 60°S and 30°N and 31–35 km of altitude for all months and between 0° and 30°N below 16 km during June (nighttime).     

Nondestructive testing of honeycomb structures by computerized,thermographic systems

Complex honeycomb space structures (i.e. antennas, solar panels, etc.) must be inspected and accurately tested before flight.The thermography can be employed with success for the detection of the position of defects (delaminations, noneffective bondings, cracks, etc.) and for the evaluation of their size and geometry in all the cases in which the defect acts as a thermal resistance due to the low conductivity of the air filling the defect volume.The basic idea is to create in the specimen a heat flow distribution that is altered by the presence of the defect.The surface temperature distribution is then measured by means of a thermograph and is correlated with the presence of the defect.A numerical analysis and preliminary experiments have been carried out which show the feasibility of the method as applied to honeycomb structures.     

Variations of the solar acoustic high-degree mode frequencies over solar cycle 23

Using full-disk observations obtained with the Michelson Doppler Imager (MDI) on board the Solar and Heliospheric Observatory (SOHO) spacecraft, we present variations of the solar acoustic mode frequencies caused by the solar activity cycle. High-degree (100 < ? < 900) solar acoustic modes were analyzed using global helioseismology analysis techniques over most of solar cycle 23. We followed the methodology described in details in [Korzennik, S.G., Rabello-Soares, M.C., Schou, J. On the determination of Michelson Doppler Imager high-degree mode frequencies. ApJ 602, 481–515, 2004] to infer unbiased estimates of high-degree mode parameters ([see also Rabello-Soares, M.C., Korzennik, S.G., Schou, J. High-degree mode frequencies: changes with solar cycle. ESA SP-624, 2006]). We have removed most of the known instrumental and observational effects that affect specifically high-degree modes. We show that the high-degree changes are in good agreement with the medium-degree results, except for years when the instrument was highly defocused. We analyzed and discuss the effect of defocusing on high-degree estimation. Our results for high-degree modes confirm that the frequency shift scaled by the relative mode inertia is a function of frequency and it is independent of degree.     

Command Link Encoder for Gemini Rendezvous

The first application of a magnetic encoder in a space-to-space command link was proven successful in the Gemini rendezvous missions. The functional aspects of the command link and the mechanization of the encoder are described.     

Studies of Logarithmic Radar Receiver Using Pulse-Length Discrimination

Using a logarithmic amplifier giving a detected output followed by a high-pass filter is a technique for reducing adverse effects of distributed clutter in radar receivers. A pulse-length discriminator (PLD) used as the high-pass filter is treated here. Theoretical and experimental results for the loss in detectability introduced by this receiver, as compared with a matched filter or a good approximation thereto, have been obtained. For the case of single-hit detection, losses of 4 to 8 dB are introduced by the logarithmic amplifier/pulse-length discriminator (LOG AMP/PLD) combination; for post-detection integration, the losses are reduced to 2 to 4 dB. The latter values would apply where the LOG AMP/PLD output is presented on a PPI (plan position indicator). Some experimental results of the ability of the LOG AMP/PLD receiver to reject signals of incorrect pulse length show that signals exceeding the design pulse length by more than 25 to 50 percent are effectively suppressed. No significant short-pulse discrimination is obtained from the receiver.     

Hydrocarbons in terrestrial samples and the Orgueil meteorite

Meteorites contain extraterrestrial carbonaceous materials. The Alais, Orgueil, Tonk, and Ivuna meteorites resemble in their carbon, free sulfur, and non-metamorphosed mineral contents, densities, and general appearances certain organic-rich terrestrial sediments. Structural and isotopic determinations of carbon compounds in the Orgueil chondrite indicate that these compounds are primarily indigenous. Physically and chemically the benzene extractable carbonaceous materials from the Orgueil and certain near-surface terrestrial sediments are similar. Mass spectrometric type analyses of the alkanes from an Orgueil fragment, terrestrial sediments and organisms are statistically indistinguishable at the 95 per cent confidence level. Theoretical considerations and experimental data are presented, and these permit an assessment of the potential and reliability of hydrocarbons as biological indicators. Based on the production and preservation or organic substances in terrestrial environments, alkanes in the Alais, Orgueil, Tonk, and Ivuna (Type I) carbonaceous chondrites could retain the best evidence of organisms that may have lived on a parent body of meteorites.A portion of the research reported in this article was supported by the National Aeronautics and Space Administration under Contract No. NASw 508.     

Theory of Operation of an Elastically Supported Tuned Gyroscope

Detailed derivation of the transfer function for a multigimbal, elastically supported, tuned gyro is presented and comparison made between its characteristics and those of a classical two-axis, free-rotor gyro. Knowledge of the gyro transfer function is necessary for the purpose of servo analysis of the system in which the gyro is used; also, the transfer function is a basis of evaluation of errors caused by angular inputs that occur at twice spin frequency.