2,161 research outputs found
Flexible operation of CSIRO's post-combustion CO2 capture pilot plant at the AGL Loy Yang power station
Flexible operation has the potential to significantly improve the economic viability of post-combustion CO2 capture (PCC). However, the impact of disturbances from flexible operation of the PCC process is unclear. The purpose of this study was to investigate the effects of flexible operation in a PCC pilot plant by implementing step-changes for improved dynamic data reliability. The flexible operation campaign was conducted at the CSIRO PCC pilot plant at AGL Loy Yang using monoethanolamine (MEA) absorbent. The pilot plant was operated under a broad range of transient conditions (changing flue gas flow, liquid absorbent flow and steam pressure) to capture the dynamics of a PCC process during flexible operation. The study demonstrated that the dynamics of flue gas flow rate was faster than absorbent flow rate. The greatest CO2 removal% was achieved at the lowest flue gas flow rate or at the highest absorbent flow rate; however, the latter provided improved energy efficiency. The steam pressure parameter could adjust the temperature of all columns simultaneously which can be used to compensate for effects from ambient conditions or heat losses. These results verify the technical feasibility of flexible PCC operation and provide a suitable dataset for dynamic model validation
Antineutrino emission and gamma background characteristics from a thermal research reactor
The detailed understanding of the antineutrino emission from research
reactors is mandatory for any high sensitivity experiments either for
fundamental or applied neutrino physics, as well as a good control of the gamma
and neutron backgrounds induced by the reactor operation. In this article, the
antineutrino emission associated to a thermal research reactor: the OSIRIS
reactor located in Saclay, France, is computed in a first part. The calculation
is performed with the summation method, which sums all the contributions of the
beta decay branches of the fission products, coupled for the first time with a
complete core model of the OSIRIS reactor core. The MCNP Utility for Reactor
Evolution code was used, allowing to take into account the contributions of all
beta decayers in-core. This calculation is representative of the isotopic
contributions to the antineutrino flux which can be found at research reactors
with a standard 19.75\% enrichment in U. In addition, the required
off-equilibrium corrections to be applied to converted antineutrino energy
spectra of uranium and plutonium isotopes are provided. In a second part, the
gamma energy spectrum emitted at the core level is provided and could be used
as an input in the simulation of any reactor antineutrino detector installed at
such research facilities. Furthermore, a simulation of the core surrounded by
the pool and the concrete shielding of the reactor has been developed in order
to propagate the emitted gamma rays and neutrons from the core. The origin of
these gamma rays and neutrons is discussed and the associated energy spectrum
of the photons transported after the concrete walls is displayed.Comment: 14 pages, 11 figures, Data in Appendix A and B (13 pages
Mechanical Attributes of Fractal Dragons
Fractals are ubiquitous natural emergences that have gained increased
attention in engineering applications, thanks to recent technological
advancements enabling the fabrication of structures spanning across many
spatial scales. We show how the geometries of fractals can be exploited to
determine their important mechanical properties, such as the first and second
moments, which physically correspond to the center of mass and the moment of
inertia, using a family of complex fractals known as the dragons
Differentiable Physics-based Greenhouse Simulation
We present a differentiable greenhouse simulation model based on physical
processes whose parameters can be obtained by training from real data. The
physics-based simulation model is fully interpretable and is able to do state
prediction for both climate and crop dynamics in the greenhouse over very a
long time horizon. The model works by constructing a system of linear
differential equations and solving them to obtain the next state. We propose a
procedure to solve the differential equations, handle the problem of missing
unobservable states in the data, and train the model efficiently. Our
experiment shows the procedure is effective. The model improves significantly
after training and can simulate a greenhouse that grows cucumbers accurately.Comment: Accepted at the Machine Learning and the Physical Sciences workshop,
NeurIPS 2022. 7 pages, 2 figure
On subgroups in division rings of type
Let be a division ring with center . We say that is a {\em
division ring of type } if for every two elements the division
subring is a finite dimensional vector space over . In this paper
we investigate multiplicative subgroups in such a ring.Comment: 10 pages, 0 figure
New antineutrino energy spectra predictions from the summation of beta decay branches of the fission products
In this paper, we study the impact of the inclusion of the recently measured
beta decay properties of the Tc, Mo, and
Nb nuclei in an updated calculation of the antineutrino energy spectra
of the four fissible isotopes U, and Pu. These
actinides are the main contributors to the fission processes in Pressurized
Water Reactors. The beta feeding probabilities of the above-mentioned Tc, Mo
and Nb isotopes have been found to play a major role in the component
of the decay heat of Pu, solving a large part of the
discrepancy in the 4 to 3000\,s range. They have been measured using the Total
Absorption Technique (TAS), avoiding the Pandemonium effect. The calculations
are performed using the information available nowadays in the nuclear
databases, summing all the contributions of the beta decay branches of the
fission products. Our results provide a new prediction of the antineutrino
energy spectra of U, Pu and in particular of U for
which no measurement has been published yet. We conclude that new TAS
measurements are mandatory to improve the reliability of the predicted spectra.Comment: 10 pages, 2 figure
Primary Colorectal Adenocarcinoma Metastatic to the Breast: Case Report and Review of Nineteen Cases
Metastases to the breast from extramammary primaries are uncommon and account for 0.5–6% of all breast malignancies (Georgiannos et al., 2001, and Vizcaíno et al., 2001). Malignant melanoma, lymphoma, and lung and gastric carcinomas are the most frequently encountered nonmammary metastases to the breast in adults (Georgiannos et al., 2001, and Chaignaud et al., 1994). Primary colorectal adenocarcinoma (CRC) metastatic to the breast is extremely rare, with the medical literature having only 19 recorded cases. Typically CRC metastatic to the breast is indicative of widely disseminated disease and a poor prognosis. Here we present a case of poorly differentiated colon cancer metastatic to the breast and review the current literature on this rare event
Magneto-transport properties of monolayer borophene in perpendicular magnetic field: influence of electron-phonon interaction
The magneto-transport properties of a borophene monolayer in a perpendicular magnetic field B are studied via calculating the conductivity tensor and resistance under electron-optical phonon interaction by using the linear response theory. Numerical results are obtained and discussed for some specific parameters. The magnetic field-dependent longitudinal conductivity shows the magneto-phonon resonance effect that describes the transition of electrons between Landau levels by absorbing/emitting an optical phonon. The Hall conductivity increases first and then decreases with the magnetic field strength. Also, the longitudinal resistance increases significantly with increasing temperature, which shows the metal behaviour of the material. Practically, the observed magneto-phonon resonance can be applied to experimentally determine some material parameters, such as the distance between Landau levels and the optical phonon energy
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