Determination of the risk propagation path of cascading faults in chemical material networks based on complex networks

A mainly theoretical study has been undertaken to demonstrate how the extent of cover from a hyperbolic navigation system chain can be evaluated. The impetus for the study was the need to assess how Loran-C could be extended over Western Europe, particularly in the South western Approaches, North Sea, English Channel and Bay of Biscay sea areas.The technique described in this article leads to an accurate determination of the electric field strength at a distance from each transmitting site and takes into account the complexities of the ground-wave propagation path. This field-strength contour is combined with the geometric effects of station siting (expansion factors) to yield a constant S/N contour (–10 dB) which defines the ¼n.m. error and hence the limit of cover for the hyperbolic chain under study.In order to exercise the analytical methods a hypothetical Loran-C chain was studied comprising a master station at Lessay (France), with secondary stations at Soustons (also in France), at Sylt (dual rated; off the North Sea coast of Germany, near the Danish border) and at a fourth station located in north-west Britain on the Hebridean island of Barra. The study indicated that such a hypothetical chain would significantly improve Loran-C cover over much of western Europe.

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THE POLARIZATION CHARACTERISTICS OF Pi-2 MICROPULSATIONS AND THEIR RELATION TO THE DETERMINATION OF POSSIBLE SOURCE MECHANISMS FOR THE PRODUCTION OF NIGHTTIME IMPULSIVE MICROPULSATION ACTIVITY

Canadian Journal of Physics ◽

10.1139/p67-099 ◽

1967 ◽

Vol 45 (3) ◽

pp. 1319-1335 ◽

Cited By ~ 61

Author(s):

Gordon Rostoker

Keyword(s):

Southern Hemisphere ◽

Northern Hemisphere ◽

Horizontal Plane ◽

Auroral Zone ◽

Propagation Path ◽

Source Mechanisms ◽

Polarization Characteristics ◽

Direction Of Polarization

From the analysis of 20 separate events it is shown that Pi-2 micropulsations are polarized in an anticlockwise sense in the horizontal plane at northern-hemisphere mid-latitude stations. Combined with the knowledge that in the southern hemisphere polarization is predominantly in the clockwise sense, it can be inferred that at least the last part of the propagation path of the Pi 2 from the auroral zone to the observing station is traversed in the Alfvén mode. The presence of occasional pulsations possessing clockwise polarization in the northern hemisphere and anticlockwise polarization in the southern hemisphere suggests that the Alfvén mode alone is insufficient to explain the mode of propagation of a Pi 2. It is shown how ionospheric screening may influence the direction of polarization of a micropulsation. It is found that the initial kick of a Pi-2 micropulsation is strongly related to the sign of the accompanying geomagnetic bay. Deviations from this trend are discussed and it is shown that the Pi-2 micropulsation train and the initial kick may be considered as two separate effects. A theory for the origin of Pi-2 micropulsations is proposed.

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Determination of an Outdoor Path Loss Model and Signal Penetration Level in Some Selected Modern Residential and Office Apartments in Ogbomosho, Oyo State, Nigeria

Journal of Engineering Research and Reports ◽

10.9734/jerr/2018/v1i29804 ◽

2018 ◽

pp. 1-25

Author(s):

V. O. A. Akpaida ◽

F. I. Anyasi ◽

S. I. Uzairue ◽

A. I. Idim

Keyword(s):

Building Materials ◽

Path Loss ◽

Signal Strength ◽

Base Stations ◽

Propagation Path ◽

Loss Model ◽

Path Loss Model ◽

Path Loss Exponent ◽

Received Power

This article involves the site specific determination of an outdoor path loss model and Signal penetration level in some selected modern residential and office apartments in Ogbomosho, Oyo State. Measurements of signal strength and its associated location parameters referenced globally were carried out. Propagation path loss characteristics of Ogbomosho were investigated using three different locations with distinctively different yet modern building materials. Consequently, received signal strength (RSS) was measured at a distance d in meters, from appropriate base stations for various environments investigated. The data were analyzed to determine the propagation path loss exponent, signal penetration level and path loss characteristics. From calculations, the average building penetration losses were, 5.93dBm, 6.40dBm and 6.1dBm outside the hollow blocks B1, solid blocks B2 and hollow blocks mixed with pre cast asbestos B3, buildings respectively with a corresponding path loss exponent values of, 3.77, 3.80 and 3.63. Models were developed and validated, and used to predict the received power inside specific buildings. Moreover, the propagation models developed for the different building types can be used to predict the respective signal level within the building types, once the transmitter – receiver distance is known. The readings obtained from the developed models were compared with both the measured values and values computed using some existing models with satisfactory results obtained.

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