15,825 research outputs found
Reconsidering Ocean Incineration as Part of a U.S. Hazardous Waste Management Program: Separating the Rhetoric from the Reality
A creep model for metallic composites based on matrix testing: Application to Kanthal composites
An anisotropic creep model is formulated for metallic composites with strong fibers and low to moderate fiber volume percent (less than 40 percent). The idealization admits no creep in the local fiber direction and assumes equal creep strength in longitudinal and transverse shear. Identification of the matrix behavior with that of the isotropic limit of the theory permits characterization of the composite through uniaxial creep tests on the matrix material. Constant and step-wise creep tests are required as a data base. The model provides an upper bound on the transverse creep strength of a composite having strong fibers embedded in a particular matrix material. Comparison of the measured transverse strength with the upper bound gives an assessment of the integrity of the composite. Application is made to a Kanthal composite, a model high-temperature composite system. Predictions are made of the creep response of fiber reinforced Kanthal tubes under interior pressure
Regulating Municipal Solid Waste Incinerators Under the Clean Air Act: History, Technology and Risks
The SoLid anti-neutrino detector's readout system
The SoLid collaboration have developed an intelligent readout system to
reduce their 3200 silicon photomultiplier detector's data rate by a factor of
10000 whilst maintaining high efficiency for storing data from anti-neutrino
interactions. The system employs an FPGA-level waveform characterisation to
trigger on neutron signals. Following a trigger, data from a space time region
of interest around the neutron will be read out using the IPbus protocol. In
these proceedings the design of the readout system is explained and results
showing the performance of a prototype version of the system are presented
Adaptable-radius, time-orbiting magnetic ring trap for Bose-Einstein condensates
We theoretically investigate an adjustable-radius magnetic storage ring for
laser-cooled and Bose-condensed atoms. Additionally, we discuss a novel
time-dependent variant of this and other ring traps. Time-orbiting ring traps
provide a high optical access method for spin-flip loss prevention near a
storage ring's circular magnetic field zero. Our scalable storage ring will
allow one to probe the fundamental limits of condensate Sagnac interferometry.Comment: 5 pages, 3 figures. accepted in J Phys
On the Classification of Quasihomogeneous Functions
We give a criterion for the existence of a non-degenerate quasihomogeneous
polynomial in a configuration, i.e. in the space of polynomials with a fixed
set of weights, and clarify the relation of this criterion to the necessary
condition derived from the formula for the Poincar\'e polynomial. We further
prove finiteness of the number of configurations for a given value of the
singularity index. For the value 3 of this index, which is of particular
interest in string theory, a constructive version of this proof implies an
algorithm for the calculation of all non-degenerate configurations.Comment: 12 page
Thermalization vs. Isotropization & Azimuthal Fluctuations
Hydrodynamic description requires a local thermodynamic equilibrium of the
system under study but an approximate hydrodynamic behaviour is already
manifested when a momentum distribution of liquid components is not of
equilibrium form but merely isotropic. While the process of equilibration is
relatively slow, the parton system becomes isotropic rather fast due to the
plasma instabilities. Azimuthal fluctuations observed in relativistic heavy-ion
collisions are argued to distinguish between a fully equilibrated and only
isotropic parton system produced in the collision early stage.Comment: 12 pages, presented at `Correlations and Fluctuations in Relativistic
Nuclear Collisions', MIT, April 05, minor correction
Cosmic dust in the stratosphere
Balloonborne sampling technique for stratospheric collection of cosmic dus
Controlled engineering of extended states in disordered systems
We describe how to engineer wavefunction delocalization in disordered systems
modelled by tight-binding Hamiltonians in d>1 dimensions. We show analytically
that a simple product structure for the random onsite potential energies,
together with suitably chosen hopping strengths, allows a resonant scattering
process leading to ballistic transport along one direction, and a controlled
coexistence of extended Bloch states and anisotropically localized states in
the spectrum. We demonstrate that these features persist in the thermodynamic
limit for a continuous range of the system parameters. Numerical results
support these findings and highlight the robustness of the extended regime with
respect to deviations from the exact resonance condition for finite systems.
The localization and transport properties of the system can be engineered
almost at will and independently in each direction. This study gives rise to
the possibility of designing disordered potentials that work as switching
devices and band-pass filters for quantum waves, such as matter waves in
optical lattices.Comment: 14 pages, 11 figure
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