SEARCH · Search NASA
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Very low frequency signal propagation, electron and solid state physics, automatic control processes, communications and networks, ferromagnetism, and electromagnetic waves
Perturbation factors in angular correlation function for multidomain ferromagnetic materials determined taking into account magnetic field fluctuations
Strong fine-mesh screens are fabricated by a method involving uniform distribution of fine ferromagnetic particles on a nonmagnetic plate. Such screens are commonly used for grids in electron tubes and ion devices.
Advantages and disadvantages of controlling magnetization in ferromagnetic material to produce torques required for satellite attitude control
Limit switch for reliable, low-travel, snap action with negligible arcing uses an electrically nonconductive permanent magnet consisting of a ferrimagnetic ceramic and ferromagnetic pole shoes which form a magnetic and electrically conductive circuit with a ferrous-metal armature.
Synthesizing fluid light modulator using ferromagnetic fluid for transducing electrical signal into corresponding spatial transparency distribution
Quantum structure in ferromagnetic metals dielectric function, noting anomalous helicon and magnon propagation modes in uniform magnetic field
Stainless steel sensitization analyzed using Mossbauer spectroscopy and X ray diffraction, noting ferromagnetic phase
Lunar rocks magnetic properties and natural remanent magnetization, examining pyroxene paramagnetism, ferrosilite and ilmenite antiferromagnetism and native iron ferromagnetism
Apollo 11 lunar fines glass spherules magnetic properties, considering soft and hard ferromagnetic components
Capacitor fabrication by solidifying mixture of ferromagnetic metal particles, nonferromagnetic particles, and dielectric material
Magnetization versus field and temperature analyses of ferromagnetic material in Apollo 12 lunar samples
Electron spin resonance studies of Apollo 11 and 12 lunar soil samples, determining ferromagnetism due to Fe particles
New design is proposed for ferrofluidic solenoid with low magnetic flux leakage. Solenoid consists of a coil centered within a football-shaped elastomeric capsule filled with a ferromagnetic fluid. Fluid replaces the solid, movable core of conventional solenoids, and elastomeric capsule acts as return spring.
Sensitive magnetometer capable of measuring field strengths of 10 nanogauss is described. High permeability core is aligned parallel to magnetic field in first stage. In second stage, ferromagnetic toroid saturates rapidly. Adjustment of turns and area ratios of each stage provides wide range of sensitivities.
A simple and convenient method of making quantitative magnetic separations of the lunar fines is described. The fractions obtained form groups containing distinctively different particle types; thus it appears that magnetic separation in itself may be a useful way of characterizing lunar fines. Mossbauer studies of fines 10084 show that the metal can not contain more than about 1.5% Ni implying that by far the bulk of it results from reduction rather than being a direct meteoritic addition. Mossbauer data also places an upper limit on the magnetite content of the fines at least an order of magnitude below that required to account for the characteristic ferromagnetic resonance observed. Microscopic examination of magnetic separates from the 15101 fines suggests that reduction of Fe accompanies every major impact event on the moon and also suggests that the bulk of the material at the collection site has at one time been in an impact plume.
A process for making ferromagnetic films with high permeability and development of the technology for fabricating a magnetic head using these films are reported. An interim head was successfully built, tested, and delivered for evaluation and a process for sputtering high permeability films has been developed. Two heads with deposited pole tips have been tested and delivered. One had a 0.0001 inch gap and the other a 0.0003 inch gap. Both heads were boned with epoxy but served to test the geometry of the head design.
The basic equations of motion are derived for a two dimensional, three degree of freedom simulation of a space telescope coupled to a spacecraft by means of a magnetic suspension and isolation system. The system consists of paramagnetic or ferromagnetic discs confined to the magnetic field between two Helmholtz coils. Damping is introduced by varying the magnetic field in proportion to a velocity signal derived from the telescope. The equations of motion are nonlinear, similar in behavior to the one-dimensional Van der Pol equation. The computer simulation was verified by testing a 264-kilogram air bearing platform which simulates the telescope in a frictionless environment. The simulation demonstrated effective isolation capabilities for disturbance frequencies above resonance. Damping in the system improved the response near resonance and prevented the build-up of large oscillatory amplitudes.