26 research outputs found
Superstatistics as the statistics of quasi-equilibrium states: Application to fully developed turbulence
In non-equilibrium states, currents are produced by irreversible processes
that take a system toward the equilibrium state, where the current vanishes. We
demonstrate, in a general setting, that a superstatistics arises when the
system relaxes to a (stationary) quasi-equilibrium state instead, where only
the \textit{mean} current vanishes because of fluctuations. In particular, we
show that a current with Gaussian white noise takes the system to a unique
class of quasi-equilibrium states, where the superstatistics coincides with
Tsallis escort -distributions. Considering the fully developed turbulence as
an example of such quasi-equilibrium states, we analytically deduce the
power-law spectrum of the velocity structure functions, yielding a correction
to the log-normal model which removes its shortcomings with regard to the
decreasing higher order moments and the Novikov inequality, and obtain
exponents that agree well with the experimental data.Comment: To appear in Phys. Rev. E (2011
Superselection from canonical constraints
The evolution of both quantum and classical ensembles may be described via
the probability density P on configuration space, its canonical conjugate S,
and an_ensemble_ Hamiltonian H[P,S]. For quantum ensembles this evolution is,
of course, equivalent to the Schroedinger equation for the wavefunction, which
is linear. However, quite simple constraints on the canonical fields P and S
correspond to_nonlinear_ constraints on the wavefunction. Such constraints act
to prevent certain superpositions of wavefunctions from being realised, leading
to superselection-type rules. Examples leading to superselection for energy,
spin-direction and `classicality' are given. The canonical formulation of the
equations of motion, in terms of a probability density and its conjugate,
provides a universal language for describing classical and quantum ensembles on
both continuous and discrete configuration spaces, and is briefly reviewed in
an appendix.Comment: MiKTex 2.3, no figures, minor clarifications, to appear in J. Phys.
Berry effect in acoustical polarization transport in phononic crystals
We derive the semiclassical equations of motion of a transverse acoustical
wave packet propagating in a phononic crystal subject to slowly varying
perturbations. The formalism gives rise to Berry effect terms in the equations
of motion, manifested as the Rytov polarization rotation law and the
polarization-dependent Hall effect. We show that the formalism is also
applicable to the case of non-periodic inhomogeneous media, yielding explicit
expressions for the Berry effect terms.Comment: To appear in JETP Let
One-loop approximation of Moller scattering in Krein-space quantization
It has been shown that the negative-norm states necessarily appear in a
covariant quantization of the free minimally coupled scalar field in de Sitter
spacetime [1,2]. In this processes ultraviolet and infrared divergences have
been automatically eliminated [3]. A natural renormalization of the one-loop
interacting quantum field in Minkowski spacetime () has been
achieved through the consideration of the negative-norm states defined in Krein
space. It has been shown that the combination of quantum field theory in Krein
space together with consideration of quantum metric fluctuation, results in
quantum field theory without any divergences [4]. Pursuing this approach, we
express Wick's theorem and calculate M{\o}ller scattering in the one-loop
approximation in Krein space. The mathematical consequence of this method is
the disappearance of the ultraviolet divergence in the one-loop approximation.Comment: 10 page
Macroscopic effects of the spectral structure in turbulent flows
Two aspects of turbulent flows have been the subject of extensive, split
research efforts: macroscopic properties, such as the frictional drag
experienced by a flow past a wall, and the turbulent spectrum. The turbulent
spectrum may be said to represent the fabric of a turbulent state; in practice
it is a power law of exponent \alpha (the "spectral exponent") that gives the
revolving velocity of a turbulent fluctuation (or "eddy") of size s as a
function of s. The link, if any, between macroscopic properties and the
turbulent spectrum remains missing. Might it be found by contrasting the
frictional drag in flows with differing types of spectra? Here we perform
unprecedented measurements of the frictional drag in soap-film flows, where the
spectral exponent \alpha = 3 and compare the results with the frictional drag
in pipe flows, where the spectral exponent \alpha = 5/3. For moderate values of
the Reynolds number Re (a measure of the strength of the turbulence), we find
that in soap-film flows the frictional drag scales as Re^{-1/2}, whereas in
pipe flows the frictional drag scales as Re^{-1/4} . Each of these scalings may
be predicted from the attendant value of \alpha by using a new theory, in which
the frictional drag is explicitly linked to the turbulent spectrum. Our work
indicates that in turbulence, as in continuous phase transitions, macroscopic
properties are governed by the spectral structure of the fluctuations.Comment: 6 pages, 3 figure
Chemical constituents of sea buckthorn (Hippophae rhamnoides L.) fruit in populations of central Alborz Mountains in Iran
Background and objectives: Hippophae rhamnoides L. known as sea buckthorn is a deciduous medicinal shrub belonging to Elaeagnaceae family. In this study, the most important chemical constituents of sea buckthornwere evaluated in wild populations of central Alborz Mountains in Iran during the growth season of 2014 and 2015. Methods: Phytochemical analysis of fruit pulp and seed oil traits was performed using different methods of chromatography such as spectrophotometry, HPLC and GC. Results: Based on the results of combined analysis of variance, significant (p≤0.01) difference ranges between populations were found in respect to fruit dry weight (21.32 to 32.03%), total phenolic compounds (20.78 to 34.60 mg/g), extractable tannin (1.99 to 5.74 mg/g), glucose (38.14 to 110.70 mg/g), total carotenoids (0.80 to 1.17 mg/g), lycopene (0.13 to 0.20 mg/g), β-carotene (0.18 to 0.26 mg/g), total flavonoids (0.98 to 2.80 mg/g), total soluble solids (TSS) (11.85 to 31.50%), vitamin C (1.47 to 8.96 mg/g), seed oil content (4.51 to 7.91%), and two major unsaturated fatty acids including linoleic acid (28.71 to 37.44%) and linolenic acid (21.52 to 28.28%). Factor analysis based on principal component analysis (PCA) revealed most important traits with the highest correlation factor such as vitamin C, carbohydrates, TSS, fruit dry weight (FDW), and tannin for the first component. Conclusion: content of vitamin C was the main variable in chemical constituents for effective detection of original wild populations of central Alborz Mountains. Accordingly, sea buckthorn populations were divided into four main clusters and groups with high diversity based on their chemical compositions
Phytochemical and growth responses of Mentha piperita
The biostimulant products are able to improve quality and quantity of medicinal plants.
The comparative effects of biostimulants foliar spraying on peppermint (Mentha piperita L.)
were investigated.
These studies were done on the basis of randomized complete blocks design in 3 replicates
during 2015.
In field conditions, the highest leaves and stems dry weight by 400 mg/l chitosan (CH) + 400
mg/l citric acid (CA), essential oil content by 200 mg/l chitosan + 400 mg/l humic acid (HA) + 400 mg/l
citric acid and menthol content in 200 mg/l chitosan + 800 mg/l humic acid + 400 mg/l citric acid were
observed. In greenhouse conditions, the best results of those mentioned parameters were obtained by 400
mg/l chitosan + 800 mg/l humic acid + 400 mg/l citric acid, 800 mg/l humic acid and 400 mg/l chitosan
+ 400 mg/l humic acid + 400 mg/l citric acid, respectively.Produkty biostymulujące mają właściwości podnoszące jakość i plon roślin leczniczych.
Porównanie efektów spryskiwania biosymulatorami liści mięty pieprzowej.
Badanie przeprowadzono w 2015 r. metodą wybranych losowo kompletnych bloków w trzech powtórzeniach.
W warunkach polowych najwyższy plon suchej masy łodyg i liści otrzymano przy zastosowaniu 400
mg/l chitosanu (CH) + 400 mg/l kwasu cytrynowego (CA), zawartość olejku eterycznego przy użyciu 200
mg/l chitosanu + 400 mg/l kwasu humusowego (HA) + 400 mg/l kwasu cytrynowego oraz zawartość mentolu
przy zastosowaniu 200 mg/l chitosanu + 800 mg/l kwasu humusowego + 400 mg/l kwasu cytrynowego.
W warunkach szklarniowych najlepsze wyniki powyższych parametrów uzyskano, stosując odpowiednio
400 mg/l chitosanu + 800 mg/l kwasu humusowego + 400 mg/l kwasu cytrynowego, 800 mg/l kwasu humusowego
oraz 400 mg/l chitosanu + 400 mg/l kwasu humusowego + 400 mg/l kwasu cytrynowego.Stosowanie dolistne efektywnych biostymulantów może podnieść jakość i plon mięty pieprzowej
Odpowiedź biochemiczna i wzrost Mentha piperita po dolistnym podaniu biostymulatorów w warunkach szklarniowych i polowych
The biostimulant products are able to improve quality and quantity of medicinal plants.
The comparative effects of biostimulants foliar spraying on peppermint (Mentha piperita L.)
were investigated.
These studies were done on the basis of randomized complete blocks design in 3 replicates
during 2015.
In field conditions, the highest leaves and stems dry weight by 400 mg/l chitosan (CH) + 400
mg/l citric acid (CA), essential oil content by 200 mg/l chitosan + 400 mg/l humic acid (HA) + 400 mg/l
citric acid and menthol content in 200 mg/l chitosan + 800 mg/l humic acid + 400 mg/l citric acid were
observed. In greenhouse conditions, the best results of those mentioned parameters were obtained by 400
mg/l chitosan + 800 mg/l humic acid + 400 mg/l citric acid, 800 mg/l humic acid and 400 mg/l chitosan
+ 400 mg/l humic acid + 400 mg/l citric acid, respectively.Produkty biostymulujące mają właściwości podnoszące jakość i plon roślin leczniczych.
Porównanie efektów spryskiwania biosymulatorami liści mięty pieprzowej.
Badanie przeprowadzono w 2015 r. metodą wybranych losowo kompletnych bloków w trzech powtórzeniach.
W warunkach polowych najwyższy plon suchej masy łodyg i liści otrzymano przy zastosowaniu 400
mg/l chitosanu (CH) + 400 mg/l kwasu cytrynowego (CA), zawartość olejku eterycznego przy użyciu 200
mg/l chitosanu + 400 mg/l kwasu humusowego (HA) + 400 mg/l kwasu cytrynowego oraz zawartość mentolu
przy zastosowaniu 200 mg/l chitosanu + 800 mg/l kwasu humusowego + 400 mg/l kwasu cytrynowego.
W warunkach szklarniowych najlepsze wyniki powyższych parametrów uzyskano, stosując odpowiednio
400 mg/l chitosanu + 800 mg/l kwasu humusowego + 400 mg/l kwasu cytrynowego, 800 mg/l kwasu humusowego
oraz 400 mg/l chitosanu + 400 mg/l kwasu humusowego + 400 mg/l kwasu cytrynowego.Stosowanie dolistne efektywnych biostymulantów może podnieść jakość i plon mięty pieprzowej