10,323 research outputs found
Occupational Mortality, Age at Marriage and Marital Fertility Early Twentieth Century England and Wales
What factors determine fertility and to what extent do we really understand the decision processes that underpinned when to marry, when to start having children and how many children to have in the historical past? In many ways, the posing of such questions may seem surprising given the now copious literature on the subject.1 In this paper we use new datasets built from previously under-exploited primary source materials and improved econometric modelling to build on previous work and thereby improve on our understanding of the determinants of the demand for children in early twentieth century England and Wales
Experimental assembly of structures in EVA: Hardware morphology and development issues
A large body of data was obtained by MIT during neutral boyancy testing at Marshall Space Flight Center from 1980 to the present. These efforts, and the most significant results are summarized. The Experimental Assembly of Structure in EVA (EASE) flight experiment was undertaken to validate these results and flown on the STS 61-B in November 1985. The EASE experiment hardware is discussed and how the experiment goals dictate its size, shape, and operational characteristics, are illustrated
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Surface mineral crusts: A priority target in search for life on Mars
Mineral crusts are strong candidates in the search for evidence of life during planetary exploration, and should be an important target for examination in impact craters. Crusts in the Haughton crater readily yield a biological signature
Observation of the Isotopic Evolution of Pressurized Water Reactor Fuel Using an Antineutrino Detector
By operating an antineutrino detector of simple design during several fuel
cycles, we have observed long term changes in antineutrino flux that result
from the isotopic evolution of a commercial Pressurized Water Reactor (PWR).
Measurements made with simple antineutrino detectors of this kind offer an
alternative means for verifying fissile inventories at reactors, as part of
International Atomic Energy Agency (IAEA) and other reactor safeguards regimes.Comment: 9 pages, 8 figures; Submitted to Journal of Applied Physics v2: added
new figure plus various clarifications and grammatical revision
Evaluation of advanced lift concepts and potential fuel conservation for short-haul aircraft
The effect of different field lengths, cruise requirements, noise level, and engine cycle characteristics on minimizing fuel consumption and minimizing operating cost at high fuel prices were evaluated for some advanced short-haul aircraft. The conceptual aircraft were designed for 148 passengers using the upper surface-internally blown jet flap, the augmentor wing, and the mechanical flap lift systems. Advanced conceptual STOL engines were evaluated as well as a near-term turbofan and turboprop engine. Emphasis was given to designs meeting noise levels equivalent to 95-100 EPNdB at 152 m (500 ft) sideline
Penetration of Air Jets Issuing from Circular, Square, and Elliptical Orifices Directed Perpendicularly to an Air Stream
An experimental investigation was conducted to determine the penetration of air jets d.irected perpendicularlY to an air stream. Jets Issuing from circular, square, and. elliptical orifices were investigated. and. the jet penetration at a position downstream of the orifice was determined- as a function of jet density, jet velocity, air-stream d.enaity, air-stream velocity, effective jet diameter, and. orifice flow coeffIcient. The jet penetrations were determined for nearly constant values of air-stream density at three tunnel-air velocities arid for a large range of Jet velocities and. densities. The results were correlated in terms of dimensionless parameters and the penetrations of the various shapes were compared. Greater penetration was obtained. with the square orifices and the elliptical orifices having an axis ratio of 4:1 at low tunnel-air velocities and low jet pressures than for the other orifices investigated. The square orifices gave the best penetrations at the higher values of tunnel-air velocity and jet total pressure
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