1,061 research outputs found
Inverse turbulent cascades and conformally invariant curves
We offer a new example of conformal invariance far from equilibrium -- the
inverse cascade of Surface Quasi-Geostrophic (SQG) turbulence. We show that
temperature isolines are statistically equivalent to curves that can be mapped
into a one-dimensional Brownian walk (called Schramm-Loewner Evolution or
SLE). The diffusivity is close to , that is iso-temperature
curves belong to the same universality class as domain walls in the O(2) spin
model. Several statistics of temperature clusters and isolines are measured and
shown to be consistent with the theoretical expectations for such a spin system
at criticality. We also show that the direct cascade in two-dimensional
Navier-Stokes turbulence is not conformal invariant. The emerging picture is
that conformal invariance may be expected for inverse turbulent cascades of
strongly interacting systems.Comment: 4 pages, 6 figure
Two-dimensional elastic turbulence
We investigate the effect of polymer additives on a two-dimensional
Kolmogorov flow at very low Reynolds numbers by direct numerical simulations of
the Oldroyd-B viscoelastic model. We find that above the elastic instability
threshold the flow develops the elastic turbulence regime recently observed in
experiments. We observe that both the turbulent drag and the Lyapunov exponent
increase with Weissenberg, indicating the presence of a disordered,
turbulent-like mixing flow. The energy spectrum develops a power-law scaling
range with an exponent close to the experimental and theoretical expectations
Market Innovation, Rational Housing Supply and Urban Quality at the Neighbourhood Scale
Innovation of product, process and markets are the three categories to assess the improvement of a sector. This document is aimed to provide a review of papers about innovation in housing market and analyses solutions adopted by the international market in terms of definition of attributes of housing products.
Enlightening aspects linked to quality attributes of housing products and it has been tried to read a common scheme in any study analysed to provide solutions to set innovation hints to enhance market innovation in the sector. The idea of choice, user and buyer categories definition, assessment and rating system is the backbone of the paper, as the parallelism between marketing of industrial goods and services and built environment objects. Quality of the neighbourhood and the idea of an ex-post assessment is the theme behind the last case presented, based on a research made by ABC Department of Politecnico di Milano in a neighbourhood in Milano, aimed to assess its quality
A retrospective study of cryptorchidectomy in horses: Diagnosis, treatment, outcome and complications in 70 cases
The aim of the study was to investigate the breed predisposition and the diagnostic and surgical management of horses referred for cryptorchidism. The breed, localization of retained testis, diagnosis, type of surgical treatment and complications were analyzed. Seventy horses were included in the study; the Western Riding horse breeds were the most affected (Quarter Horse 34/70, 48.5%; Appaloosa 9/70, 12.8%). In unilateral cryptorchids (65/70, 92.8%) the most common location for a retained testis was the left abdomen (28/65, 43%), while in bilateral cryptorchids (5/70, 7.1%), bilateral abdominal retention was the most frequent (3/5, 6%). Information about testis localization was achieved through transabdominal ultrasound (30/49 cases, 61.2%), through per rectum palpation (21/49 cases, 42.9%) and through inguinal palpation (14/49 cases, 28.9%). Cryptorchidectomy was achieved with standing laparoscopy (44/70 cases, 62.8%), or with open inguinal orchiectomy in general anesthesia (26/70 cases, 37.2%). Complications during laparoscopy were spleen puncture (1/44, 2.2%), a self-limiting bleeding from the spermatic cord (10/44 cases, 22.7%), hyperthermia (3/44 cases, 6.8%), and emphysema (15/44, 34%). During inguinal open cryptorchidectomy difficulties with identifying the inguinal testis during surgery (8/26 cases, 30.8%) and a moderate and self-limiting swelling of the inguinal region after surgery (17/26, 65.4%) were observed. For orchiectomy, a standing laparoscopy was confirmed as the preferred procedure for an abdominally retained testis with almost no complications
Statistical conservation laws in turbulent transport
We address the statistical theory of fields that are transported by a
turbulent velocity field, both in forced and in unforced (decaying)
experiments. We propose that with very few provisos on the transporting
velocity field, correlation functions of the transported field in the forced
case are dominated by statistically preserved structures. In decaying
experiments (without forcing the transported fields) we identify infinitely
many statistical constants of the motion, which are obtained by projecting the
decaying correlation functions on the statistically preserved functions. We
exemplify these ideas and provide numerical evidence using a simple model of
turbulent transport. This example is chosen for its lack of Lagrangian
structure, to stress the generality of the ideas
Site-selection on the basis of territorial analysis methods
The object of research is the site-selection process for the rental housing construction. This form of real estate is becoming more widespread in the west, while in Russia it's development is currently on initial stage. The article proposes the site-selection solution on the basis of existing methods of territorial analysis, calculation of employment shares, location quotients, Hirschmann-Herfindahl index and Kano model application, as well as application examples of the obtained databases in the conditions of a narrowly formulated problem. The research results are the mechanisms for solving three types of problems depending on the nature of the initial data according to correspondence between the properties of the object under construction and the urban territories
Finitely generated free Heyting algebras via Birkhoff duality and coalgebra
Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and
thus the free algebras can be obtained by a direct limit process. Dually, the
final coalgebras can be obtained by an inverse limit process. In order to
explore the limits of this method we look at Heyting algebras which have mixed
rank 0-1 axiomatizations. We will see that Heyting algebras are special in that
they are almost rank 1 axiomatized and can be handled by a slight variant of
the rank 1 coalgebraic methods
Advection of a passive scalar field by turbulent compressible fluid: renormalization group analysis near
The field theoretic renormalization group (RG) and the operator product
expansion (OPE) are applied to the model of a density field advected by a
random turbulent velocity field. The latter is governed by the stochastic
Navier-Stokes equation for a compressible fluid. The model is considered near
the special space dimension . It is shown that various correlation
functions of the scalar field exhibit anomalous scaling behaviour in the
inertial-convective range. The scaling properties in the RG+OPE approach are
related to fixed points of the renormalization group equations. In comparison
with physically interesting case , at additional Green function
has divergences which affect the existence and stability of fixed points. From
calculations it follows that a new regime arises there and then by continuity
moves into . The corresponding anomalous exponents are identified with
scaling dimensions of certain composite fields and can be systematically
calculated as series in (the exponent, connected with random force) and
. All calculations are performed in the leading one-loop
approximation.Comment: 11pages, 6 figures, LATEX2e. arXiv admin note: substantial text
overlap with arXiv:1611.00327; text overlap with arXiv:1611.0130
Strong Universality in Forced and Decaying Turbulence
The weak version of universality in turbulence refers to the independence of
the scaling exponents of the th order strcuture functions from the
statistics of the forcing. The strong version includes universality of the
coefficients of the structure functions in the isotropic sector, once
normalized by the mean energy flux. We demonstrate that shell models of
turbulence exhibit strong universality for both forced and decaying turbulence.
The exponents {\em and} the normalized coefficients are time independent in
decaying turbulence, forcing independent in forced turbulence, and equal for
decaying and forced turbulence. We conjecture that this is also the case for
Navier-Stokes turbulence.Comment: RevTex 4, 10 pages, 5 Figures (included), 1 Table; PRE, submitte
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