62,883 research outputs found
Carbon Trading with Blockchain
Blockchain has the potential to accelerate the deployment of emissions
trading systems (ETS) worldwide and improve upon the efficiency of existing
systems. In this paper, we present a model for a permissioned blockchain
implementation based on the successful European Union (EU) ETS and discuss its
potential advantages over existing technology. We propose an ETS model that is
both backwards compatible and future-proof, characterised by
interconnectedness, transparency, tamper-resistance and high liquidity.
Further, we identify key challenges to implementation of a blockchain ETS, as
well as areas of future work required to enable a fully-decentralised
blockchain ETS
The Ultimate Halo Mass in a LCDM Universe
In the far future of an accelerating LCDM cosmology, the cosmic web of
large-scale structure consists of a set of increasingly isolated halos in
dynamical equilibrium. We examine the approach of collisionless dark matter to
hydrostatic equilibrium using a large N-body simulation evolved to scale factor
a = 100, well beyond the vacuum--matter equality epoch, a_eq ~ 0.75, and 53/h
Gyr into the future for a concordance model universe (Omega_m ~ 0.3,
Omega_Lambda ~ 0.7). The radial phase-space structure of halos -- characterized
at a < a_eq by a pair of zero-velocity surfaces that bracket a dynamically
active accretion region -- simplifies at a > 10 a_eq when these surfaces merge
to create a single zero-velocity surface, clearly defining the halo outer
boundary, rhalo, and its enclosed mass, mhalo. This boundary approaches a fixed
physical size encompassing a mean interior density ~ 5 times the critical
density, similar to the turnaround value in a classical Einstein-deSitter
model. We relate mhalo to other scales currently used to define halo mass
(m200, mvir, m180b) and find that m200 is approximately half of the total
asymptotic cluster mass, while m180b follows the evolution of the inner zero
velocity surface for a < 2 but becomes much larger than the total bound mass
for a > 3. The radial density profile of all bound halo material is well fit by
a truncated Hernquist profile. An NFW profile provides a somewhat better fit
interior to r200 but is much too shallow in the range r200 < r < rhalo.Comment: 5 pages, 3 figures, submitted to MNRAS letter
Design, development and use of the finite element machine
Some of the considerations that went into the design of the Finite Element Machine, a research asynchronous parallel computer are described. The present status of the system is also discussed along with some indication of the type of results that were obtained
Etching of High Purity Zinc
A method of etching high purity zinc to reveal various etch figures on {101¯0} planes is presented in this
paper. Etch figures are formed by polishing in a dichromic acid solution after the introduction of mercury
to the crystal surface. No measurable aging time is required to form etch figures at newly formed dislocation
sites when mercury is on the surface prior to deformation. The mercury concentrates at the sites
where etch figures form and may be removed by vacuum distillation and chemical polishing before it appreciably
affects the purity of the bulk of the crystal
Infrared Lighting Does Not Suppress Catch of Codling Moth (Lepidoptera: Tortricidae) in Pheromone-Baited Monitoring Traps
Video cameras are increasingly being used to record insect behaviors in the field over prolonged intervals. A nagging question about crepuscular and nocturnal recordings is whether or not infrared light emitted by such cameras to illuminate the scene influences the behaviors of the subjects or study outcomes. Here we quantified catches of male codling moths, Cydia pomonella (L.), responding to sex pheromone-baited monitoring traps illuminated with infrared, red, white, or no light. No statistically significant differences were found between any of these treatments
Hexagonal spiral growth in the absence of a substrate
Experiments on the formation of spiraling hexagons (350 - 1000 nm in width)
from a solution of nanoparticles are presented. Transmission electron
microscopy images of the reaction products of chemically synthesized cadmium
nanocrystals indicate that the birth of the hexagons proceeds without
assistance from static screw or edge dislocatons, that is, they spiral without
constraints provided by an underlying substrate. Instead, the apparent growth
mechanism relies on what we believe is a dynamical dislocation identified as a
dense aggregate of small nanocrystals that straddles the spiraling hexagon at
the crystal surface. This nanocrystal bundle, which we term the "feeder", also
appears to release nanocrystals into the spiral during the growth process.Comment: 4 pages, 5 figure
The effects of long-day lighting and removal of young leaves on tomato yield
While low intensity long-day (LD) lighting has been shown to enhance the growth of young plants under low light levels, its effect on the yield of a long-season glasshouse tomato crop has not been previously examined. LD were provided by the use of tungsten lamps (2.8 μmol m-2 s-1 at approx. 0.5 m from the ground) between 04.00 h to sunrise and from sunset until 20.00 h (GMT). LD lighting increased leaf chlorophyll contents, and the numbers of flowers and fruits set per truss when the plants were young. However, this treatment did not affect the total yield of tomatoes. Different leaf removal treatments were applied within each glasshouse compartment. A previous experiment had shown that reducing the leaf area index (LAI) from 5.2 to 2.6, by removing old leaves, did not affect yield. It was also thought that removal of young leaves reduced the total vegetative sink-strength and favoured assimilate partitioning into the fruit. Therefore, removal of young leaves could increase fruit yield. In the present experiments, one-third of the leaves were removed in March (those immediately below each truss) and, subsequently, every third leaf was removed at an early stage of its development. This reduced the LAI from 4.1 to 2.9 and resulted in a loss of yield from 3 – 4 weeks after leaf removal until the end of the experiment, at which point there was an 8% loss of cumulative yield due to a reduction in the average number of fruits set per truss and in mean fruit weight. We postulate that the light which would have been intercepted by young photosynthetically-efficient leaves at the top of the canopy was intercepted instead by older leaves which were less efficient, reducing overall net canopy photosynthesis
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