"Magnetoscan": A Modified Hall Probe Scanning Technique for the Detection of Inhomogeneities in Bulk High Temperature Superconductors

We present a novel technique for the investigation of local variations of the critical current density in large bulk superconductors. In contrast to the usual Hall probe scanning technique, the sample is not magnetized as a whole before the scan, but locally by a small permanent magnet, which is fixed near the Hall probe, during the scanning process. The resulting signal can be interpreted as a qualitative measure of the local shielding currents flowing at the surface.Comment: 8 pages, 4 figure

Ending Neglect of older people in the response to Humanitarian Emergencies

Older people make up a significant and growing number of those affected by humanitarian crises, yet they are often not sought out or prioritised within the humanitarian response. Humanitarian agencies, donors, and international bodies neglect older people's health and nutrition. The gaps in knowledge and research about the needs of older people in emergencies are considerable. Older people are not monitored in emergencies and they are not prioritised despite evidence of disproportionate mortality and morbidity in this group. We call for policy changes by humanitarian agencies and donors to ensure that the needs of this vulnerable group are met

The 2.5-5.0 micron spectra of Io: Evidence for H2S and H2O frozen in SO2

The techniques of low temperature spectroscopy are applied to identify the constituents of the ices covering the surface of Io, a satellite of Jupiter. Infrared spectra of Io in the 4000-2000 cm exp -1 region, including new observational data, are analyzed using laboratory studies of plausible surface ices

Study of Interfacial Stress in Metal Matrix Composites Using Ultrasonic Velocity Measurements

The numerous potential applications of metal matrix composites (MMCs) in the military and aerospace industries have resulted in the widespread study of their mechanical properties to determine optimum fabrication techniques for improved composite strength. Due to the difference in the thermal expansion coefficients of the matrix material and its reinforcement, thermally-induced residual stresses exist in the composite as a direct result of cooling from the MMC fabrication temperature. Several nondestructive techniques have been used to determine the residual stress present in various engineering materials. Radiographic techniques have been used extensively, but are somewhat limited in penetration depth and spatial resolution. However, ultrasonic techniques have proven to be a useful nondestructive means of determining bulk mechanical properties of a material. To determine the influence of internal stresses in MMCs on ultrasonic velocities, specimens of various second-phase silicon carbide content were subjected to a change in temperature. As the specimen temperature was raised, interfacial stresses between the aluminum matrix and silicon carbide reinforcement were relaxed, resulting in an overall change in the stress state of the material. Longitudinal ultrasonic waves were used to measure the acoustoelastic effect due to this change in the internal stress of the MMC. Longitudinal waves have been successfully used to determine internal stresses due to the influence of temperature on railroad rails [1] and prestrained aluminum and copper specimens [2]. The ultrasonic velocities in this investigation were measured with a computer automated time-of-flight acquisition system accurate to better than 1 part in 10,000

Djidjelli

Dans l’univers djidjellien, deux mondes se conjuguent : un monde maritime, à vocation méditerranéenne ; un monde rural, profondément enraciné dans les reliefs du Nord Constantinois. Ajoutons à cela une petite plaine côtière, la seule de Kabylie orientale à présenter quelque dimension, et nous connaîtrons par avance le destin d’une cité promise à l’essor ou à l’isolement suivant les caprices de l’histoire. Alternances de fortunes, célébrité, oublis, mystères même, telle apparaît aujourd’hui la..

Ala Miliaria

Ville de Maurétanie Césarienne à l’époque romaine. Son nom vient de l’unité militaire, l’Ala Miliaria, qui y tenait garnison. L’implantation correspond actuellement au lieu dit Bénian, à 37 km au sud-sud est de Mascara, et 35 km au nord-nord est de Saïda (Wilaya de Mascara, Algérie). En arabe, le mot Bénian recouvre une idée d’habitation ancienne. Géographiquement, le point se localise dans la partie ouest des Monts de Saïda, au centre de la chaîne continue de l’Atlas tellien oranais. Le site..

Kerfala

Nom d’un centre de regroupement des populations environnantes créé en 1976 par application d’une ordonnance du président H. Boumediene, visant à construire sur le territoire algérien 100 « villages socialistes ». Chacun de ces villages devait posséder une Assemblée populaire communale (APC), une mosquée et une école. Le nom de Kerfala est désormais lié à la découverte sur le site d’une remarquable stèle sépulcrale libyque inscrite et figurée. Topographie Au centre du village de Kadiria (ex-Th..

Djidjelli

Dans l’univers djidjellien, deux mondes se conjuguent : un monde maritime, à vocation méditerranéenne ; un monde rural, profondément enraciné dans les reliefs du Nord Constantinois. Ajoutons à cela une petite plaine côtière, la seule de Kabylie orientale à présenter quelque dimension, et nous connaîtrons par avance le destin d’une cité promise à l’essor ou à l’isolement suivant les caprices de l’histoire. Alternances de fortunes, célébrité, oublis, mystères même, telle apparaît aujourd’hui la..