Showing papers on "Shields published in 1968"

Protection against space radiation

Abstract: Space radiation transport, spacecraft shielding design and advanced concepts, and methods for calculating radiation penetration through protective shields - conference

Experimental studies on shadow shields for thermal protection of cryogenic tanks in space

Abstract: : Experiments were performed on multiple flat-disk shadow shields to determine the effects of shield spacing number, emissivity, lateral conductance, and targeting (high-emissivity coatings on annular rings of shields) on thermal performance. The experimental data, in general, agreed closely with an analytical model which assumed diffuse surfaces with nonuniform radiosity. A shadow-shield system for a hypothetical space vehicle was designed, scaled down, and tested. Results demonstrated: (1) a lightweight method of shield construction; (2) shield-support interactions: and (3) reduction of support heat leaks by shield location, attachment methods, and the use of high-emissivity coatings.

Ultrahigh frequency tuner with helical resonators coupled through apertures in shields

Abstract: Tuner for miniature radio receiver operating at ultrahigh frequency including coils and individual conductive shields forming helical resonators The coils are tuned at the lowimpedance end by aluminum slugs providing low loss, and may be capacitively loaded at the high-impedance end Apertures in the shields provide coupling between the adjacent resonators, with the aperture in one shield being of the size to control the coupling and the aperture in the adjacent shield being larger so that it does not affect the coupling

Radiation shields for furnaces

Abstract: This invention relates to radiation shields for furnaces. Such shields are made of a removable ray protection element and a plurality of foil layers.

Minimum attenuation of spherical shields

Abstract: In this communication, a simple formula for the minimum attenuation of incoming plane waves in spherical shields is presented for practical purposes. This worst case condition is attained when the TM 011 resonance occurs in the room. The medium inside and outside the shield is air and the material is supposed to be well conducting.

Analog Studies of Magnetic Shields

Abstract: Externally deflecting magnets provide a protective region around space vehicles which shields them from the hazardous space radiation. The magnetic shield simulator (MAGSIM) is an analog device that provides a simple means for directly measuring the forbidden volume or protective region produced by externally deflecting magnets. The MAG SIM has been employed to determine the protective volume for certain complex magnet configurations. These configurations include two coplanar coaxial current loops of different radii, and two quasihollow conductor configurations. In addition, the assumption of substituting an equivalent simple loop for a hollow conductor has been checked. In general, the simple-loop approximation predicts results in agreement with measurements with the hollow conductor magnet; however, the measured outward displacement of the forbidden volume from the center of the magnet is approximately 20% larger than that predicted by simple-loop theory. The ability to shape the forbidden region to match the shape of the vehicle is described.

Cathode with graphite end shields

Abstract: A tungsten dispenser cathode for a magnetron is described. The cathode is provided with end shields in the form of solid graphite rings to improve suppression of undesirable electron emission.

Inflatable solar shields for cryogenic space vehicles.

Abstract: Inflatable solar shields for thermal protection of space vehicles utilizing cryogen propellants

Direct Design Solution for Cassegrain Shields

Abstract: A direct algebraic desigll oi Cassegraill light shields is proposed, usillg ollly the assul1lption that the mirror surfaces are fla t. lntrodllction During the design and construction of a Cassegrain or Ritchey-Chretien telescope, the design of an adequate shielding is required in order to avoid direct sky light falling on the focal planeo A sol ution to this problem has been worked out by means of a graphical method, using succesive approximationst, and later applied to electronic computers2. Recently, a different graphical solution has been explained, based also on succesive approximations3. Therefore, the possibility of a direct solution was studied. The final goal was reached using in this method only the approximation of considering the surfaces of the mirrors as plane surfaces. Parameters 01 a Cassegrain system. The main purpose of the shields in a Cassegrain system is to avoid direct sky light falling on the image planeo As the field increases the required shielding introduces two new problems, vignetting and central obscuration. The central obscuration is produced by the large size of the diameter of the shield at the secondary mirror and the vignetting is due to both shields. (See Fig. 2). Hence as it is pointed out by Young(2), these factors will set the conditions for the solution of the problem and will establish a compromise between the allowable field size and central obscuration.