17,428 research outputs found
Instrument for measuring the dynamic behavior of liquids Patent
Pressure sensor network for measuring liquid dynamic response in flight including fuel tank acceleration, liquid slosh amplitude, and fuel depth monitorin
Mechanical properties and oxidation and corrosion resistance of reduced-chromium 304 stainless steel alloys
An experimental program was undertaken to identify effective substitutes for part of the Cr in 304 stainless steel as a method of conserving the strategic element Cr. Although special emphasis was placed on tensile properties, oxidation and corrosion resistance were also examined. Results indicate that over the temperature range of -196 C to 540 C the yield stress of experimental austenitic alloys with only 12 percent Cr compare favorably with the 18 percent Cr in 304 stainless steel. Oxidation resistance and in most cases corrosion resistance for the experimental alloys were comparable to the commercial alloy. Effective substitutes for Cr included Al, Mo, Si, Ti, and V, while Ni and Mn contents were increased to maintain an austenitic structure
Oxidation and corrosion behavior of modified-composition, low-chromium 304 stainless steel alloys
The effects of substituting less strategic elements than Cr on the oxidation and corrosion resistance of AISI 304 stainless steel were investigated. Cyclic oxidation resistance was evaluated at 870 C. Corrosion resistance was determined by exposure of specimens to a boiling copper-rich solution of copper sulfate and sulfuric acid. Alloy substitutes for Cr included Al, Mn, Mo, Si, Ti, V, Y, and misch metal. A level of about 12% Cr was the minimum amount of Cr required for adequate oxidation and corrosion resistance in the modified composition 304 stainless steels. This represents a Cr saving of at least 33%. Two alloys containing 12% Cr and 2% Al plus 2% Mo and 12% Cr plus 2.65% Si were identified as most promising for more detailed evaluation
Sphere forming method and apparatus
A system is provided for forming small accurately spherical objects. Preformed largely spherical objects are supported at the opening of a conduit on the update of hot gas emitted from the opening, so the object is in a molten state. The conduit is suddenly jerked away at a downward incline, to allow the molten object to drop in free fall, so that surface tension forms a precise sphere. The conduit portion that has the opening, lies in a moderate vacuum chamber, and the falling sphere passes through the chamber and through a briefly opened valve into a tall drop tower that contains a lower pressure, to allow the sphere to cool without deformation caused by falling through air
Health and sustainable development
If sustainable development is to mean anything, people must be healthy enough to benefit from it and not have their lives cut off prematurely. Development without health is meaningless. But the processes which are likely to occur in a world undergoing globalisation, climate change, urbanisation, population increase and many other changes, will impact upon human health in complex ways. Some of them will benefit us, others will create new or augmented threats to survival and health, while many others will have a complex mixture of effects
Two-Loop Crossover Scaling Functions of the O(N) Model
Using Environmentally Friendly Renormalization, we present an analytic
calculation of the series for the renormalization constants that describe the
equation of state for the model in the whole critical region. The
solution of the beta-function equation, for the running coupling to order two
loops, exhibits crossover between the strong coupling fixed point, associated
with the Goldstone modes, and the Wilson-Fisher fixed point. The Wilson
functions , and , and thus the
effective critical exponents associated with renormalization of the transverse
vertex functions, also exhibit non-trivial crossover between these fixed
points.Comment: 21 pages, 4 figures, version to appears in IJMPL
Critical Temperature and Amplitude Ratios from a Finite-Temperature Renormalization Group
We study \l\f^4 theory using an environmentally friendly finite-temperature
renormalization group. We derive flow equations, using a fiducial temperature
as flow parameter, develop them perturbatively in an expansion free from
ultraviolet and infrared divergences, then integrate them numerically from zero
to temperatures above the critical temperature. The critical temperature, at
which the mass vanishes, is obtained by integrating the flow equations and is
determined as a function of the zero-temperature mass and coupling. We
calculate the field expectation value and minimum of the effective potential as
functions of temperature and derive some universal amplitude ratios which
connect the broken and symmetric phases of the theory. The latter are found to
be in good agreement with those of the three-dimensional Ising model obtained
from high- and low-temperature series expansions.Comment: 14 pages of LaTeX. Postscript figures available upon request form
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