267,377 research outputs found
Persistence in systems with algebraic interaction
Persistence in coarsening 1D spin systems with a power law interaction
is considered. Numerical studies indicate that for sufficiently
large values of the interaction exponent ( in our
simulations), persistence decays as an algebraic function of the length scale
, . The Persistence exponent is found to be
independent on the force exponent and close to its value for the
extremal () model, . For smaller
values of the force exponent (), finite size effects prevent the
system from reaching the asymptotic regime. Scaling arguments suggest that in
order to avoid significant boundary effects for small , the system size
should grow as .Comment: 4 pages 4 figure
Constructed wetlands: Treatment of concentrated storm water runoff (part A)
The aim of this research was to assess the treatment efficiencies for gully pot liquor of experimental vertical-
flow constructed wetland filters containing Phragmites australis (Cav.) Trin. ex Steud. (common
reed) and filter media of different adsorption capacities. Six out of 12 filters received inflow water spiked
with metals. For 2 years, hydrated nickel and copper nitrate were added to sieved gully pot liquor to simulate
contaminated primary treated storm runoff. For those six constructed wetland filters receiving heavy
metals, an obvious breakthrough of dissolved nickel was recorded after road salting during the first winter.
However, a breakthrough of nickel was not observed, since the inflow pH was raised to eight after
the first year of operation. High pH facilitated the formation of particulate metal compounds such as nickel
hydroxide. During the second year, reduction efficiencies of heavy metal, 5-days at 20°C N-Allylthiourea
biochemical oxygen demand (BOD) and suspended solids (SS) improved considerably. Concentrations of
BOD were frequently �20 mg/L. However, concentrations for SS were frequently �30 mg/L. These are
the two international thresholds for secondary wastewater treatment. The BOD removal increased over
time due to biomass maturation, and the increase of pH. An analysis of the findings with case-based reasoning
can be found in the corresponding follow-up paper (Part B)
Spinon Phonon Interaction and Ultrasonic Attenuation in Quantum Spin Liquids
Several experimental candidates for quantum spin liquids have been discovered
in the past few years which appear to support gapless fermionic excitations called spinons. The spinons may form a Fermi sea coupled to a
gauge field, and may undergo a pairing instability. We show that despite
being charge neutral, the spinons couple to phonons in exactly the same way
that electrons do in the long wavelength limit. Therefore we can use sound
attenuation to measure the spinon mass and lifetime. Furthermore, transverse
ultrasonic attenuation is a direct probe of the onset of pairing because the
Meissner effect of the gauge field causes a "rapid fall" of the attenuation at
in addition to the reduction due to the opening of the energy gap. This
phenomenon, well known in clean superconductors, may reveal the existence of
the U(1) gauge field.Comment: 4+epsilon pages of main text + 12 pages of supplementary materia
Constructed wetlands: Prediction of performance with case-based reasoning (part B)
The aim of this research was to assess the treatment efficiencies for gully pot liquor of experimental vertical-
flow constructed wetland filters containing Phragmites australis (Cav.) Trin. ex Steud. (common reed)
and filter media of different adsorption capacities. Six out of 12 filters received inflow water spiked with
metals. For 2 years, hydrated nickel and copper nitrate were added to sieved gully pot liquor to simulate
contaminated primary treated storm runoff. The findings were analyzed and discussed in a previous paper
(Part A). Case-based reasoning (CBR) methods were applied to predict 5 days at 20°C N-Allylthiourea biochemical
oxygen demand (BOD) and suspended solids (SS), and to demonstrate an alternative method of
analyzing water quality performance indicators. The CBR method was successful in predicting if outflow
concentrations were either above or below the thresholds set for water-quality variables. Relatively small
case bases of approximately 60 entries are sufficient to yield relatively high predictions of compliance of
at least 90% for BOD. Biochemical oxygen demand and SS are expensive to estimate, and can be cost-effectively
controlled by applying CBR with the input variables turbidity and conductivity
Instanton solutions mediating tunneling between the degenerate vacua in curved space
We investigate the instanton solution between the degenerate vacua in curved
space. We show that there exist -symmetric solutions not only in de
Sitter but also in both flat and anti-de Sitter space. The geometry of the new
type of solutions is finite and preserves the symmetry. The nontrivial
solution corresponding to the tunneling is possible only if gravity is taken
into account. The numerical solutions as well as the analytic computations
using the thin-wall approximation are presented. We expect that these solutions
do not have any negative mode as in the instanton solution.Comment: Some typos are corrected and references are added with respect to the
published version. 17pages, 11fi
Fully automatic telemetry data processor
Satellite Telemetry Automatic Reduction System /STARS 2/, a fully automatic computer-controlled telemetry data processor, maximizes data recovery, reduces turnaround time, increases flexibility, and improves operational efficiency. The system incorporates a CDC 3200 computer as its central element
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