Investigation of the differential rotation of the large-scale magnetic elements for the solar activity cycles 20 and 21

The differential rotation of the patterns of the large-scale solar magnetic field during solar activity cycles 20 and 21 is investigated. Compact magnetic elements with the polarity of the general solar magnetic field have larger speed of rotation than the elements with the opposite polarity. The surface of the Sun was divided by 10°-zones. In all of them the average rotation rate of the magnetic elements with negative polarity is little higher than that of the magnetic elements with positive polarity, except for 50°-zone of the south hemisphere and at the 10° latitude of the north hemisphere.

The rates of differential rotation for large-scale magnetic elements with negative and positive polarities have similar behavior for both cycles of the solar activity.

The rotation rate varies at polarity reversal of the circumpolar magnetic fields. For the cycle No 20 in 1969–1970 the threefold reversal took place in the northern hemisphere and variations of rotation rate can be noticed for magnetic elements both with positive and negative polarity for each 10°-zone in the same hemisphere.     

Problems of application of face gasodynamic seals in aircraft engines

Problems arising in introduction of gasodynamic seals in aircraft engines are considered. The operation of a face gasodynamic seal as part of a natural gas pump is analyzed and its efficiency in the presence of oil is shown.     

Two years of INTEGRAL observation of the BHC IGR J17464-3213

On March 2003, IBIS, the γ-ray imager on board the INTEGRAL satellite, detected an outburst from a new source, IGR J17464-3213, that turned out to be an HEAO-1 transient, namely H1743-322. The spectral and temporal evolutions of the source were observed by INTEGRAL in different periods. Also RXTE observed the source for the first time on 2003 March 29 during a PCA Galactic bulge scan. The source flux decayed below the RXTE PCA sensitivity limit in November 2003, then in April 2004 it was again detected by INTEGRAL. On July 3, 2004 the source was again detected by RXTE/PCA at a 2–10 keV intensity of 16 mCrab and on July 7, reached 69 mCrab. Recently, a new outburst was observed on August 2005. We briefly summarise here the behaviour of the source observed by INTEGRAL from March 2003 to August 2005. The new outbursts of the source and the analysis of all the data collected (now public) give a global view of the spectral and time behaviour of this X-ray transient.     

Unmanned aircraft navigation for shipboard landing using infrared vision

This paper addresses the problem of determining the relative position and orientation of an unmanned air vehicle with respect to a ship using three visible points of known separation. The, images of the points are obtained from an onboard infrared camera. The paper develops a numerical solution to this problem. Both simulation and flight test results are presented.     

Voting fusion adaptation for landmine detection

This paper presents a voting fusion application for use with a remotely controlled multisensor vehicle platform for antitank landmine detection. Data from three landmine detection sensors mounted at the front of the vehicle enhance the probability of detection and, when combined via data fusion, limit the false alarm density to practical levels. The performance of the voting fusion scheme presented in this paper is contrasted with a heuristic data fusion approach developed by General Dynamics Canada.     

Features of active sidestick controllers

This paper discusses the advantages of incorporating active sidesticks into a modern aircraft cockpit. Active sidestick controllers for manual pilot inputs in pitch and roll are examined for commercial transport aircraft. Options and requirements for sidesticks are reviewed. The recommendation of an active sidestick controller is developed providing both cross-cockpit coupling and autopilot backdrive capability. These characteristics provide pilot cues identical to traditional cable-linked column/yoke configurations     

Methodologies in user interface design

Software applications that require a high learning curve, a mountain of documentation, and weeks of training should be things of the past. Today's applications need to be simple to learn and to use. The human/computer interface should be intuitive and consistent. Context sensitive help should be available to keep the user on track. This paper provides some guidelines for taking commercial world concepts and applying them to the Automatic Test Equipment world. Examples included are from the Integrated Maintenance Information System (IMIS)     

NASA''s small spacecraft technology initiative “Clark” spacecraft

The Small Satellite Technology Initiative (SSTI) is a National Aeronautics and Space Administration (NASA) program to demonstrate smaller, high technology satellites constructed rapidly and less expensively. Under SSTI, NASA funded the development of “Clark,” a high technology demonstration satellite to provide 3-m resolution panchromatic and 15-m resolution multispectral images, as well as collect atmospheric constituent and cosmic x-ray data. The 690-Ib. satellite, to be launched in early 1997, will be in a 476 km, circular, sun-synchronous polar orbit. This paper describes the program objectives, the technical characteristics of the sensors and satellite, image processing, archiving and distribution. Data archiving and distribution will be performed by NASA Stennis Space Center and by the EROS Data Center, Sioux Falls, South Dakota, USA.     

Receiver antenna scan rate requirements needed to implement pulsechasing in a bistatic radar receiver

Pulse chasing is a technique implemented by a bistatic or multistatic radar system that allows rapid and efficient search of a desired volume of space whereby the receiving antenna is made to follow or “chase” the transmitted pulse as it travels radially outward from the transmitter antenna. An expression for receiver antenna scan rate requirements is derived that corrects an error in the prior literature. The results give significantly reduced scan rates in the forward scatter region near the baseline showing that pulse chasing is more easily implemented using conventional analog beamformer phased array technology than was suggested by prior work