1,479,499 research outputs found
The lifetime cost of a magnetic refrigerator
The total cost of a 25 W average load magnetic refrigerator using commercial
grade Gd is calculated using a numerical model. The price of magnetocaloric
material, magnet material and cost of operation are considered, and all
influence the total cost. The lowest combined total cost with a device lifetime
of 15 years is found to be in the range \^{+++}$ refrigeration unit. In a
rough life time cost comparison between the magnetic refrigeration device and
such a unit we find similar costs, the former being slightly cheaper, assuming
the cost of the magnet can be recuperated at end of life.Comment: 17 pages, 17 figure
Traffic control system and method
Frequency of carrier received by aircraft is measured and compared with reference to indicate magnitude of Doppler shift. One Doppler frequency range is selected and indicated by digital signal. Difference between frequency is offset of apparent carrier frequency transmitted by aircraft
Traffic control system and method Patent
Traffic control system for supersonic transports using synchronous satellite for data relay between vehicles and ground statio
Magnetoresistance of PrLaOsSb: Disentangling local crystalline-electric-field physics and lattice effects
Resistivity measurements were performed on PrLaOsSb
single crystals at temperatures down to 20 mK and in fields up to 18 T. The
results for dilute-Pr samples ( and 0.67) are consistent with model
calculations performed assuming a singlet crystalline-electric-field (CEF)
ground state. The residual resistivity of these crystals features a smeared
step centered around 9 T, the predicted crossing field for the lowest CEF
levels. The CEF contribution to the magnetoresistance has a
weaker-than-calculated dependence on the field direction, suggesting that
interactions omitted from the CEF model lead to avoided crossing in the
effective levels of the Pr ion. The dome-shaped magnetoresistance
observed for and 0.05 cannot be reproduced by the CEF model, and likely
results from fluctuations in the field-induced antiferroquadrupolar phase
Accelerometer-controlled automatic braking system
Braking system, which employs angular accelerometer to control wheel braking and results in low level of tire slip, has been developed and tested. Tests indicate that system is feasible for operations on surfaces of different slipperinesses. System restricts tire slip and is capable of adapting to rapidly-changing surface conditions
Flat growth of 7075, 7475, 7050 and 7049 aluminum alloy plate in stress corrosion environments: 2-year marine atmosphere results
Marine atmospheric exposure of smooth and precracked specimens from 7075, 7475, 7050 and 7049 plates support the conclusion that for a given strength level, the short transverse stress corrosion resistance of 7050-T7X and 7049-T7X is superior to that of 7075-T7X. The threshold stress intensity (K sub Iscc) for these alloys is about 25 MPa square root m at a yield strength of about 460 MPa; the corresponding yield strength level for 7075-T7X at this SCR level is about 425 MPa. Additional tests on two lots of high-toughness 7475 plate indicate that this alloy is capable of achieving K sub Iscc values of about 35 MPa square root m at yield strengths of 400-450 MPa. Precracked specimens from all these 7XXX-series alloys are subject to self loading from corrosion product wedging. This effect causes stress corrosion cracks to continue growing at very low apparent stress intensities, and should therefore be considered a potential driving force for stress corrosion in design and materials selection
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