Are Radio Pulsars Strange Stars ?

A remarkably precise observational relation for pulse core component widths of radio pulsars is used to derive stringent limits on pulsar radii, strongly indicating that pulsars are strange stars rather than neutron stars. This is achieved by inclusion of general relativistic effects due to the pulsar mass on the size of the emission region needed to explain the observed pulse widths, which constrain the pulsar masses to be less than 2.5 Solar masses and radii to be smaller than 10.5 km.Comment: v.2 : 12 pages including 3 figures and 2 tables, LaTex, uses epsfig. This version has one extra figure, few lines of new text and typos fixe

Effect of Surfactants on the Fluorescence Intensity of 9,10-Diphenylanthracene

123-12

Synthesis of Substituted Dimethylformamidyl Te(IV) & Se(IV) Chlorides

52-5

Kinetics of Ce(IV) Oxidation of Monothioglycerol in Carbonate Medium

656-65

Advanced tracking systems design and analysis

The results of an assessment of several types of high-accuracy tracking systems proposed to track the spacecraft in the National Aeronautics and Space Administration (NASA) Advanced Tracking and Data Relay Satellite System (ATDRSS) are summarized. Tracking systems based on the use of interferometry and ranging are investigated. For each system, the top-level system design and operations concept are provided. A comparative system assessment is presented in terms of orbit determination performance, ATDRSS impacts, life-cycle cost, and technological risk

Reactions of Pyruvonitrile with Nb(V) & Ta(V) Alkoxides

406-40

Kinetics of Hexacyanoferrate(III) Oxidation of 4-tert-Butylthiophenol & 2-Merhyl-a-tert-butylrhiophenol

252-25

On the Nature of Triphenylselenonium Chloride

123-12

A novel 3D multilateration sensor using distributed ultrasonic beacons for indoor navigation

Navigation and guidance systems are a critical part of any autonomous vehicle. In this paper, a novel sensor grid using 40 KHz ultrasonic transmitters is presented for adoption in indoor 3D positioning applications. In the proposed technique, a vehicle measures the arrival time of incoming ultrasonic signals and calculates the position without broadcasting to the grid. This system allows for conducting silent or covert operations and can also be used for the simultaneous navigation of a large number of vehicles. The transmitters and receivers employed are first described. Transmission lobe patterns and receiver directionality determine the geometry of transmitter clusters. Range and accuracy of measurements dictate the number of sensors required to navigate in a given volume. Laboratory experiments were performed in which a small array of transmitters was set up and the sensor system was tested for position accuracy. The prototype system is shown to have a 1-sigma position error of about 16 cm, with errors between 7 and 11 cm in the local horizontal coordinates. This research work provides foundations for the future development of ultrasonic navigation sensors for a variety of autonomous vehicle applications