7,308 research outputs found
Electrochemical Reducing of Terbium and Holmium Ions in the Sodium and Potassium Chlorides Melt with Equimolar Composition
Interest to rare-earth metals (REM) and their alloys is due to the possibility of using them for the creation of new materials need for modern technology. For instance, REM as alloying components allows for preparation of material with special magnetic properties. A promising method for forming such coating is the surface treatment of metals. This process has an electrochemical character as such for the organization of technology the knowledge of kinetics and mechanism of these processes is important. Despite significant interest in rare-earth metals, these issues are not well described in the literature. In order to choose an adequate mathematical model for calculation of kinetic primers, preliminary experiments that allow evaluating the reversibility of the electrode process have been conducted. Based on that, it was concluded that cathodic reduction of terbium and holmium ions in equimolar NaCl-KCl melt is irreversible. By means of voltammetric analysis, kinetic parameters (transfer coefficients, heterogeneous constants of charge transfer rate) of terbium and holmium electroreduction in equimolar NaCl-KCl melt were determined. The experiment was conducted in a three-electrode cell under a purified argon atmosphere. A dependency of kinetic parameters on the concentration of terbium and holmium chlorides wt (%): 1, 3, 5, 7, 10, was determined. The experiment was conducted in 1073–1173K temperature range. Values of kinetic parameters increase with temperature but decrease with the increase of REM chloride. Based on obtained data, it was found that electroreduction of chloride complexes LnCl63– (Ln–Tb, Ho) in equimolar NaCl-KCl melt is irreversible in the studied range of temperatures and REM concentrations. In summary of experimental data, in range of temperature and rare-earth chloride concentration, and assumption was made that reduction of terbium and holmium ions occurs in two stages. The process includes the preceding stage of complex dissociation. A mechanism of LnCl63– complex reduction in the mentioned melt is proposed. The obtained results are in agreement with literate data for analogues systems
Leptoquarks: Neutrino masses and accelerator phenomenology
Leptoquark-Higgs interactions induce mixing between leptoquark states with
different chiralities once the electro-weak symmetry is broken. In such LQ
models Majorana neutrino masses are generated at 1-loop order. Here we
calculate the neutrino mass matrix and explore the constraints on the parameter
space enforced by the assumption that LQ-loops explain current neutrino
oscillation data. LQs will be produced at the LHC, if their masses are at or
below the TeV scale. Since the fermionic decays of LQs are governed by the same
Yukawa couplings, which are responsible for the non-trivial neutrino mass
matrix, several decay branching ratios of LQ states can be predicted from
measured neutrino data. Especially interesting is that large lepton flavour
violating rates in muon and tau final states are expected. In addition, the
model predicts that, if kinematically possible, heavier LQs decay into lighter
ones plus either a standard model Higgs boson or a gauge boson.
Thus, experiments at the LHC might be able to exclude the LQ mechanism as
explanation of neutrino data.Comment: 28 pages, 10 figure
Maximum a posteriori estimation through simulated annealing for binary asteroid orbit determination
This paper considers a new method for the binary asteroid orbit determination
problem. The method is based on the Bayesian approach with a global
optimisation algorithm. The orbital parameters to be determined are modelled
through an a posteriori distribution made of a priori and likelihood terms. The
first term constrains the parameters space and it allows the introduction of
available knowledge about the orbit. The second term is based on given
observations and it allows us to use and compare different observational error
models. Once the a posteriori model is built, the estimator of the orbital
parameters is computed using a global optimisation procedure: the simulated
annealing algorithm. The maximum a posteriori (MAP) techniques are verified
using simulated and real data. The obtained results validate the proposed
method. The new approach guarantees independence of the initial parameters
estimation and theoretical convergence towards the global optimisation
solution. It is particularly useful in these situations, whenever a good
initial orbit estimation is difficult to get, whenever observations are not
well-sampled, and whenever the statistical behaviour of the observational
errors cannot be stated Gaussian like.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Societ
Experimental rationale for the use of fluids with different redox potential as a basis for infusion therapy
Objectives: To study the parameters of redox potential (ORP or Red-Ox) and pH of infusion solutions. To identify the general biological properties of ionized liquids with different ORP when administered by different methods to experimental animals and when applied to the wound surface. To study the effects of infusion therapy with solutions based on ionized fluids with various ORP in anaphylactic shock, bacterial sepsis, alcoholic hepatitis, dehydration, and skin injurie
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