3,464 research outputs found
A systems examination of the opportunities of coal for California
Because of decreasing availability of petroleum fuels and natural gas, it is imperative that alternative means be developed for meeting demands. The options available for importing energy derived from coal are examined. These include: (1) electric power generated from coal; (2) coal gasification near the mine site for conversion to substitute natural gas or liquid products such as methanol or hydrocarbons; and (3) converting the coal directly to liquid hydrocarbons similar to a synthetic crude oil. Comment is made on the long lead times required between conception and completion of facilities of this type. Because of political and economic impediments, excessive delays have resulted in cancellation of projects. The need for statesmen and citizens with vision and courage to act is summarized
Effects of bottom-structure flexibility on water landing loads of Apollo spacecraft models
Effect of heat shield flexibility on water landing loads of Apollo spacecraft model
Risk Assessment of Carbon Fiber Composite in Surface Transportation
The vulnerability of surface transportation to airborne carbon fibers and the national risk associated with the potential use of carbon fibers in the surface transportation system were evaluated. Results show airborne carbon fibers may cause failure rates in surface transportation of less than one per year by 1995. The national risk resulting from the use of carbon fibers in the surface transportation system is discussed
Break-up of metal tube makes one-time shock absorber, bars rebound
A frangible metal tube has the capability to dissipate the energy generated when a vehicle lands with excessive velocity. The tube is so placed that, at impact, it is forced against a die and, as it fragments, energy is absorbed
Frangible tube energy dissipation Patent
Energy dissipating shock absorbing system for land payload recovery or vehicle brakin
Is Cycle 24 the Beginning of a Dalton-Like Minimum?
The unexpected development of cycle 24 emphasizes the need for a better way
to model future solar activity. In this article, we analyze the accumulation of
spotless days during individual cycles from 1798-2010. The analysis shows that
spotless days do not disappear abruptly in the transition towards an active
sun. A comparison with past cycles indicates that the ongoing accumulation of
spotless days is comparable to that of cycle 5 near the Dalton minimum and to
that of cycles 12, 14 and 15. It also suggests that the ongoing cycle has as
much as 20 \pm 8 spotless days left, from July 2010, before it reaches the next
solar maximum. The last spotless day is predicted to be in December 2012, with
an uncertainty of 11 months. This trend may serve as input to the solar dynamo
theories.Comment: 10 pages, 5 figures. The final publication is available at
http://www.springerlink.co
Large-scale horizontal flows in the solar photosphere II: Long-term behaviour and magnetic activity response
Recently, we have developed a method useful for mapping large-scale
horizontal velocity fields in the solar photosphere. The method was developed,
tuned and calibrated using the synthetic data. Now, we applied the method to
the series of Michelson Doppler Imager (MDI) dopplergrams covering almost one
solar cycle in order to get the information about the long-term behaviour of
surface flows. We have found that our method clearly reproduces the widely
accepted properties of mean flow field components, such as torsional
oscillations and a pattern of meridional circulation. We also performed a
periodic analysis, however due to the data series length and large gaps we did
not detect any significant periods. The relation between the magnetic activity
influencing the mean zonal motion is studied. We found an evidence that the
emergence of compact magnetic regions locally accelerates the rotation of
supergranular pattern in their vicinity and that the presence of magnetic
fields generally decelerates the rotation in the equatorial region. Our results
show that active regions in the equatorial region emerge exhibiting a constant
velocity (faster by 60 +/- 9 m/s than Carrington rate) suggesting that they
emerge from the base of the surface radial shear at 0.95 R_sun, disconnect from
their magnetic roots, and slow down during their evolution.Comment: 9 pages, 8 figures, accepted for publication in Astronomy &
Astrophysic
Mott g-Ratios in Rbx(NH3)1-x and Oxidation state of Rubidium Compounds from XAS
The x-ray absorption spectra (XAS) of Rb metal, Rh,( JH,J, ,, 2H-NbSe2Rb111x and RbBr near the Rb K-edge have been used to ascertain that the oxidation state V of rubidium dissolved in ammonia and intt:rcalated in the layer compound is in the range 0 \u3c V \u3c I. Theobservededge shifts with temperature for semimctals are explainedin terms of the population of band states, and the ratio of the density states near the mobility edge over that calculated for a free electron model, i.e. the Mott ratio g, is ascertained using a semiempirical relation developed for the x-ray absorbance from Is levels to empty states ncar the mobility edge
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