82,604 research outputs found
Polynomials with prescribed bad primes
We tabulate polynomials in Z[t] with a given factorization partition, bad
reduction entirely within a given set of primes, and satisfying auxiliary
conditions associated to 0, 1, and infinity. We explain how these sets of
polynomials are of particular interest because of their role in the
construction of nonsolvable number fields of arbitrarily large degree and
bounded ramification. Finally we discuss the similar but technically more
complicated tabulation problem corresponding to removing the auxiliary
conditions.Comment: 26 pages, 3 figure
Some bounds for the knot Floer -invariant of satellite knots
We use four dimensional techniques to derive general bounds on the
invariant of a satellite knot in .Comment: 11 pages, 1 figur
Advanced low-NO(x) combustors for supersonic high-altitude gas turbines
The impact of gas-turbine-engine-powered aircraft on worldwide pollution was defined within two major areas of contribution. First, the contribution of aircraft to the local air pollution of metropolitan areas and, second, the long-term effects on the chemical balance of the stratosphere of pollutants emitted from future generations of high-altitude, supersonic commercial and military aircraft. Preliminary findings indicate that stratospheric oxides of nitrogen (NOx) emissions may have to be limited to very low levels if, for example, ozone depletion with concomitant increases in sea-level radiation, are to be avoided. Theoretical considerations suggest that (NOx) levels as low as 1.0 gram per kilogram of fuel and less should be attainable from a idealized premixed type of combustor. Experimental rig studies were intended to explore new combustor concepts designed to minimize the formation of (NOx) in aircraft gas turbines and to define their major operational problems and limitations
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