334 research outputs found
Chirally motivated K^- nuclear potentials
In-medium subthreshold KbarN scattering amplitudes calculated within a
chirally motivated meson-baryon coupled-channel model are used self
consistently to confront K^- atom data across the periodic table. Substantially
deeper K^- nuclear potentials are obtained compared to the shallow potentials
derived in some approaches from threshold amplitudes, with Re V_{chiral} =
-(85+/-5) MeV at nuclear matter density. When KbarNN contributions are
incorporated phenomenologically, a very deep K^- nuclear potential results, Re
V_{chiral+phen.} = -(180+/-5) MeV, in agreement with density dependent
potentials obtained in purely phenomenological fits to the data. Self
consistent dynamical calculations of K^- nuclear quasibound states are reported
and discussed.Comment: extended discussion, unchanged results and conclusions, accepted by
PL
Multi- nuclei and kaon condensation
We extend previous relativistic mean-field (RMF) calculations of multi- nuclei, using vector boson fields with SU(3) PPV coupling constants and
scalar boson fields constrained phenomenologically. For a given core nucleus,
the resulting separation energy , as well as the
associated nuclear and -meson densities, saturate with the number
of mesons for . Saturation
appears robust against a wide range of variations, including the RMF nuclear
model used and the type of boson fields mediating the strong interactions.
Because generally does not exceed 200 MeV, it is argued that
multi- nuclei do not compete with multihyperonic nuclei in providing
the ground state of strange hadronic configurations and that kaon condensation
is unlikely to occur in strong-interaction self-bound strange hadronic matter.
Last, we explore possibly self-bound strange systems made of neutrons and
mesons, or protons and mesons, and study their properties.Comment: 21 pages, 8 figures, revised text and reference
Application of balance models in metallurgy
In general, management is the planning and coordination of all processes and their elements in enterprises in order to achieve the objectives with the highest efficiency. The basic management tools, especially in companies with complex production processes with high inertia and long production time, include balance models. The paper points out the methodology, principles and importance of balance models in metallurgy and describes the methodology for material-energy, capacity and economic balance of this process
Order logistics for discrete and continual production processes in industry 4.0 conditions
The basic goal of the article is to define changes in production logistics and its essential part of order logistics at the transformation of the production system from an automated management system with the participation of first level logistics, managers and machine operators to a fully automated, unattended production system and at the same to define and compare the differences between discrete and continuous-discrete production typical for mining, metallurgical production processes. The solution applied the methodology of comparative analysis of the comparison of current systems of order logistics [1, 2], and its operation in terms of Industry 4.0. There were applied principles of production planning and programming of numerical control (NC) machines and robots and programcontrolled fully automated production processes, especially in the continuous character of processes for the design of a new algorithm of custom logistics [3]
Constraints on the threshold K- nuclear potential from FINUDA (stopped K-, pi-) hypernuclear spectra
1s(Lambda) hypernuclear formation rates in stopped K- reactions on several
p-shell targets are derived from hypernuclear formation spectra measured
recently by the FINUDA Collaboration and are compared with calculated
1s(Lambda) formation rates based on a KbarN coupled channels chiral model. The
calculated rates are about 15% of the derived rates, depending weakly on the
depth of the threshold K- nuclear potential. The A dependence of the calculated
rates is in fair agreement with that of the derived rates, showing a slight
preference for a deep density dependent K- nuclear potential of depth (150-200)
MeV at nuclear matter density over a shallow potential of depth about 50 MeV.
These new features originate from a substantial energy and density dependence
found for the in-medium subthreshold (K- n --> pi- Lambda) branching ratio that
serves as input to the K- capture at rest calculations.Comment: 12 pages, 2 figures, 2 tables; v2 is a substantially revised version,
v3 matches journal versio
Kaonic atoms and in-medium amplitudes
Recent work on the connection between in-medium subthreshold
amplitudes and kaonic atom potentials is updated by using a next to leading
order chirally motivated coupled channel separable interaction model that
reproduces observables at low energies, including the very recent
SIDDHARTA results for the atomic -hydrogen level shift and width. The
corresponding -nucleus potential is evaluated self-consistently within a
single-nucleon approach and is critically reviewed with respect to empirical
features of phenomenological optical potentials. The need to supplement the
single-nucleon based approach with multi-nucleon interactions is demonstrated
by showing that additional empirical absorptive and dispersive terms, beyond
the reach of chirally motivated -nucleus potentials, are required in order
to achieve good agreement with the bulk of the data on kaonic atoms.Comment: V3 updating references to match the published versio
Chemical Characterization and Identification of Organosilicon Contaminants in ISS Potable Water
2015 marked the 15th anniversary of continuous human presence on board the International Space Station. During the past year crew members from Expeditions 42-46, including two participating in a one-year mission, continued to rely on reclaimed water as their primary source of potable water. This paper presents and discusses results from chemical analyses performed on ISS water samples returned in 2015. Since the U.S. water processor assembly (WPA) became operational in 2008, there have been 5 instances of organic contaminants breaking through the treatment process. On each occasion, the breakthrough was signaled by an increase in the total organic carbon (TOC) concentration in the product water measured by the onboard TOC analyzer (TOCA). Although the most recent TOC rise in 2015 was not unexpected, it was the first time where dimethylsilanediol (DMSD) was not the primary compound responsible for the increase. Results from ground analysis of a product water sample collected in June of 2015 and returned on Soyuz 41 showed that DMSD only accounted for 10% of the measured TOC. After considerable laboratory investigation, the compound responsible for the majority of the TOC was identified as monomethysilanetriol (MMST). MMST is a low-toxicity compound that is structurally similar to DMSD
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