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176 records were found.

[[abstract]]An empirical model of electron density (Ne) was constructed by using the data obtained with an impedance probe on board Japanese Hinotori satellite. The satellite was in circular orbit of the height of 600 km with the inclination of 31 degrees from Februa
Areas of scientific investigation which are suitable for study with an Electrodynamic Tether are considered and recommendations for an evolutionary development program which ties together many of the studies are presented. The essential component of an Electrodynamic Tether System is an insulated, conducting tether. A voltage monitor and a current controller then provide a means of performing the majority of the measurements and experiments involved in the scientific investigations. The scientific areas of study which were identified include: potential difference measurements between widely spaced (10-100 km) regions in the ionosphere; plasma disturbance generation and propagation; wave injection studies in the VLF to ULF (micropulsation) region; and the current-voltage characteristic of a spherical satellite.
Consideration is given to the possibilities for studies in space plasma physics offered by a subsatellite mechanically tethered above the Space Shuttle Orbiter by a long conducting wire. The proposed experiment, designated the Shuttle Electrodynamic Tether Systems (SETS) is based on the concept of collecting electrons at the subsatellite and ejecting them from the Orbiter, made possible by the emf generated by the motion of the tether across geomagnetic field lines. The power generated in this manner can be used both for practical purposes within the Orbiter and for the creation of large-amplitude plasma and electromagnetic waves within the surrounding plasma. For a conducting spherical subsatellite 30 m in diameter with a 10-km tether drawing 1 A, calculations show that emfs on the order of 1000-2000 V and energy dissipation of as muc...
Many novel electrodynamic and space plasma physics experiments can be done from the space shuttle using a gravity gradient stabilized subsatellite tethered 10-30 km above the Orbiter via a long, conducting wire which is insulated from the ionospheric plasma. This system, called the Shuttle Electrodynamic Tether System (SETS), is described in the present paper with emphasis upon the various electrical processes which determine its coupling to the ambient plasma. The three most important physical effects include sheath formation and electron collection by the subsatellite, the generation of a large emf through the orbital motion of the tether across geomagnetic field lines, and the active ejection of electrons from the Orbiter into the surrounding ionosphere. An electrical circuit analogy is presented for SETS together with a brief outli...
During the period 3-10 February 1986 a series of major solar flares occurred on the Sun and several intense geomagnetic storms took place on the Earth. To examine the causality between the solar activity and the geomagnetic activity in this period, a magnetohydrodynamic (MHD) numerical simulation was performed using a 2 1/2 -D numerical code. In that period of February 1986, the Japanese spacecraft Sakigake was at 0.84 AU, 57 deg west of the Earth. Besides the in-situ measurements of the interplanetary plasma, Sakigake also provided Doppler scintillation observations. Comparisons between the results of the MHD simulation and the measurements made by the spacecraft Sakigake are presented.
Sustainable production systems for woodfuels in developing countries require basic information on tree productivity, and particularly on their coppicing productivity under current forms of management. We report biomass equations and sprouting productivity of two oak species (Quercus castanea and Quercus laeta) subject to traditional forms of woodfuel harvesting at Cuitzeo basin in central Mexico. Biomass components analyzed were total aboveground biomass (AGB), woody biomass suitable for charcoal making (WSC) and residues (foliage and small branches). The estimation of total aboveground biomass (AGB) and woody biomass suitable for charcoal making (WSC) of individual trees, when expressed as a function of DBH in the form y = a(DBH)b, resulted in values of pseudo-R2 higher than 92%. The Mean Annual Increment (MAI) of both species increas...
[[abstract]]Electron temperature in the sporadic E layer was measured with a glass-sealed Langmuir probe at a midlatitude station in Japan in the framework of the SEEK (Sporadic E Experiment over Kyushu)-2 campaign which was conducted in August 2002. Important findin
A 91-year-old man was diagnosed with a spontaneous pneumoperitoneum. His abdomen was soft and flat and abdominal examination revealed no tenderness or rebound tenderness. Blood examination did not show signs of inflammation. A chest X-ray demonstrated a pneumoperitoneum without pneumothorax, or pneumomediastinum. Computed tomography showed intraperitoneal free air around the liver, without any other findings. Contrast examination and endoscopy of the upper gastrointestinal tract revealed a diverticulum of a horizontal portion of the duodenum. Spontaneous pneumoperitoneum was diagnosed as being of duodenal diverticulum origin. Conservative therapy including fasting and resuscitation was initiated. Disappearance of the intraperitoneal free air was confirmed 7 days after admission. He was in good health with no clinical evidence of recurr...
Tethered rocket experiments have been carried out four times during a US-Japan joint space program in progress since 1980. The goal of the rocket program has been to perform a new type of active experiment by ejecting an electron beam from the tethered mother-daughter payload system. In the third and fourth rocket flights, the conductive tether wire was deployed more than 400 m. It was found that the tether wire acted as an antenna and its antenna impedance decreased with the extension of the wire both in HF and VLF bands. The vehicle charging due to the beam emission up to 80 mA was repeatedly measured in the series of the experiments. During the 80 mA emission, a clear evidence for the ignition of a beam plasma discharge was obtained by the plasma probe, photometers and wave receivers.
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