1,194,495 research outputs found
Efimov physics in bosonic atom-trimer scattering
Bosonic atom-trimer scattering is studied in the unitary limit using
momentum-space equations for four-particle transition operators. The impact of
the Efimov effect on the atom-trimer scattering observables is explored and a
number of universal relations is established. Positions and widths of tetramer
resonances are determined. Trimer relaxation rate constant is calculated.Comment: Added results for the trimer relaxation rate constan
Aniline effect on concrete steel rebar degradation in saline and sulfate media
Electrochemical potential monitoring experiments were performed on mild steel rebars embedded in concrete admixed with aniline inhibitor and fixed amount of sodium chloride salt partially immersed in sulfuric acid and sodium chloride solution. The open circuit potential corrosion monitoring technique was employed and the potential readings were taken in accordance with ASTM C 876. Repressive attribute and consistency of the inhibitor was then estimated by the Weibull probability density distribution as an extreme value statistical modeling approach to study performance effectiveness and to predict the most efficient inhibitor concentration in each media. Aniline effect on the compressive strengths of the reinforced concrete samples was also investigated and reported. Varying concentrations of the inhibitor were used and its performance improved as concentration changed in NaCl medium, while no particular order of performance was noted in sulfuric medium. In the statistically analyzed experimental results for each of the inhibitor concentrations employed, 0.34 and 0.41 M aniline admixed samples were identified as exhibiting the best inhibiting quality in sodium chloride while 0.14 M aniline was predicted as showing the lowest probability of corrosion risk in sulfuric acid medium. The overall effective inhibitive performance in sulfuric acid was less when compared to the sodium chloride medium. Concrete sample admixed with 0.41 M aniline had the highest improvement in compressive strength in both media
Investigating the Acid Failure of Aluminium Alloy in 2 M Hydrochloric Acid Using Vernonia amygdalina
The acid failure of aluminium alloy in 2 M hydrochloric acid solution
in the presence of Vernonia amygdalina extract was investigated using
gasometric technique. Aluminium alloy coupons of dimension 4 cm by 1 cm
were immersed in test solutions of free acid and also those containing extract
volumes of 2, 3, 4 and 5 cm3 at ambient temperature for 30 minutes. The
volumes of hydrogen gas evolved as a result of the rate of reaction were recorded
and analyzed. Analysis revealed that maximum inhibitor efficiency which
corresponds to the lowest corrosion rate was obtained at optimum inhibitor
volumes of 5 cm3, with reduction in the corrosion rate observed to follow in
order of increasing extract volumes. Adsorption study revealed that Temkin
isotherm best described the metal surface interaction with the extract
phytochemicals, with 12 minutes becoming the best exposure time for the
phytochemicals to adsorb to the metal surface at all volumes. Statistical
modelling of the corrosion rate yielded an important relationship suitable for
estimating corrosion rate values once volumes of the extract is known.
Microstructural studies, showed an indirect relationship between crack growth
rates and extract volumes, while consistency of the irregular intermetallic phases
increases with increasing extract volumes
New nonlocal effective action
We suggest a new method for the calculation of the nonlocal part of the
effective action. It is based on resummation of perturbation series for the
heat kernel and its functional trace at large values of the proper time
parameter. We derive a new, essentially nonperturbative, nonlocal contribution
to the effective action in spacetimes with dimensions .Comment: 28 pages, latex, no figures, typos are corrected, presentation
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