1,589 research outputs found
Tracing diffusion in porous media with fractal properties
This work is concerned with conditional averaging methods which can be used for modeling of transport in porous media with volume reactions in the fluid phase and surface reactions at the fluid/solid interface. The model under consideration takes into account convection, diffusion within the pores and on larger scales, and homogeneous and heterogeneous reactions. Near the interface with fractal properties, the fluid flow is slow, and diffusion, as a transport mechanism, dominates over convection. Following the conditional moment closure paradigm, we employ a diffusion tracer as a reference scalar field that makes the conditional averaging sensitive to the proximity of a point to the interface. The resulting conditionally averaged reactive transport equations are governed by the probability density function (PDF) of the diffusion tracer, and this makes the study of its behavior an important problem. We consider a hitting time stochastic interpretation of the diffusion tracer, establish integral equations relating it to a subsidiary distance tracer, and obtain distance-diffusion inequalities. Assuming that the fluid/solid interface and pores themselves possess fractal properties which are quantified, in particular, by a variant of the Minkowski-Bouligand fractal dimension, we investigate the interplay between the interface and network scenarios of fractality in the scaling laws of the diffusion tracer PDF. We also discuss and employ several hypotheses, including a lognormal cascade hypothesis on the behavior of the diffusion tracer at different length scales
Diabetic peripheral angiopathy treatment using a multi-laser therapy device
Zabulonov Y., Chukhraiyeva O., Vladimirov A., Chukhraiyev M., Zukow W. Diabetic peripheral angiopathy treatment using a multi-laser therapy device. Journal of Education, Health and Sport. 2015;5(10):227-233. ISSN 2391-8306. DOIhttp://dx.doi.org/10.5281/zenodo.32801http://ojs.ukw.edu.pl/index.php/johs/article/view/2015%3B5%2810%29%3A227-233https://pbn.nauka.gov.pl/works/662978Formerly Journal of Health Sciences. ISSN 1429-9623 / 2300-665X. Archives 2011–2014http://journal.rsw.edu.pl/index.php/JHS/issue/archive Deklaracja.Specyfika i zawartość merytoryczna czasopisma nie ulega zmianie.Zgodnie z informacją MNiSW z dnia 2 czerwca 2014 r., że w roku 2014 nie będzie przeprowadzana ocena czasopism naukowych; czasopismo o zmienionym tytule otrzymuje tyle samo punktów co na wykazie czasopism naukowych z dnia 31 grudnia 2014 r.The journal has had 5 points in Ministry of Science and Higher Education of Poland parametric evaluation. Part B item 1089. (31.12.2014).© The Author (s) 2015;This article is published with open access at Licensee Open Journal Systems of Kazimierz Wielki University in Bydgoszcz, Poland and Radom University in Radom, PolandOpen Access. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium,provided the original author(s) and source are credited. This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License(http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercial use, distribution and reproduction in any medium, provided the work is properly cited.This is an open access article licensed under the terms of the Creative Commons Attribution Non Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non commercialuse, distribution and reproduction in any medium, provided the work is properly cited.The authors declare that there is no conflict of interests regarding the publication of this paper.Received: 05.08.2015. Revised 05.09.2015. Accepted: 20.10.2015. 616.711:615.846+615.837.3DIABETIC PERIPHERAL ANGIOPATHY TREATMENT USING A MULTI-LASER THERAPY DEVICE Zabulonov Y.1, Chukhraiyeva O.1, Vladimirov A1., Chukhraiyev M.1, Zukow W.2 1Public Organization "Ukrainian Society of Physical and Rehabilitative Medicine", Kiev, Ukraine2Faculty of Physical Education, Health and Tourism, Kazimierz Wielki University, Bydgoszcz, Poland Summary The results of research on the effectiveness of multifunctional laser therapy treatment of diabetic peripheral arterial disease in patients with type 2 diabetes on the basis of a systematic approach.The clinical picture of peripheral angiopathy consists of a combination of specific diabetic angiopathy with the medium and large vessels atherosclerosis. In the case of diabetes feet the combined lesions are underlying the obliterating vascular disease. In younger diabetic patients these changes have primarily functional nature in the form of changes in vascular tone and capillaropathy.Thus, there is a need to develop efficient way to treat and prevent DPA that could actively influence the quality of life, reduce or prevent complications that arise during DPA and lower doses of pharmaceuticals. Nowadays we know several ways of physiotherapeutic treatment and prevention of complications of diabetes.Almost all patients after 3-4 sessions have a slight improvement of blood microcirculation in the lower extremities and reduce overall blood sugar level. After 10-12 treatments the test scores improve.The closest to the developed method is a method of treating diabetes and its complications prevention, which includes magnetic-laser-ultrasound therapy of the pancreas, liver and their segmental zones. This magneto-laser-ultrasound therapy treatment is combined with low-intensity electromagnetic radiation physiopuncture in a millimetric range spectrum [2].The main drawbacks of existing methods of treating complications of diabetes is that they do not involve zonal influence on the DPA area and do not include the need to influence the oxygen capacity of blood and increase its energy activity, and in this regard, the effectiveness of the treatment is generally reduced. As the base of invention is laid the task of creating such a way that dramatically improves the performance of DPA treatment in patients with diabetes and reduces the procedural burden on them.Our developed method of treating the DPA in diabetic patients is based on the simultaneous use of magnetic laser stimulation of the pancreas or liver with additional simultaneous laser irradiation of venous blood in popliteal areas and scanning laser beam therapy of the DPA area. Procedures performed 2-3 times a week. The course of treatment is 10 procedures. A second course is performed if necessary after 1-2 months. There may be some tactical changes, which are determined individually by your doctor depending on the clinical condition of the patient.The technical results, achieved by suggested solution are: increasing the effectiveness of treatment, the removal of metabolic disorders, a positive effect on the microcirculation, desintoxication of the body, increasing blood oxygen capacity and increase of its energy activities, which largely prevents complications in the treatment of DPA.Based on the proposed method treatment is performed using a laser multifunction system.Magnetic-laser stimulation of the pancreas and liver is performed, for example, using the following parameters: modulation frequency of magnetic laser - 9.4 Hz, magnetic fields up to 30 ± 10 mT, the optical flow power of red or blue range of the spectrum is 30 ± 10Wt, optical flow power of infrared spectrum - of 50±20 mW, magnetic laser applicator of red spectral range is set on the projection of the pancreas, magnetic laser applicator of infrared or blue range of the spectrum is set on the projection of the liver.Popliteal overvessel blood laser irradiation is performed using the laser emission of red spectrum range – wavelength laser 0,63 ± 0,03 mm, laser power – 20±10 mW.The DPA zones therapy with the laser scanning beam: laser wavelength – 0,63±0,03 mm, laser power – 150±50 mW, scanning figure – "Grid", the scanning dimensions – 400x200 mm. Additionally it is possible to perform nasal breathing with SOM using apparatus MIT-S. After the procedure is done the patient ingests the 50-200 ml of activated by singlet-oxygen mixture fluid. The liquid activation is held for 3 minutes.As can be seen from the data in Table 1, the patient significantly improved metabolism indicators and clinical parameters (blood pressure, pulse, bowel function, etc.). The developed method can be used in hospitals, clinics, spa facilities and therapeutic centers, etc. and be combined with drug therapy. Key words: diabetic peripheral angiopathy, a multi-laser therapy device
Optical and dc conductivities of cuprates: Spin-fluctuation scattering in the t-J model
A microscopic theory of the electrical conductivity within
the t-J model is developed. An exact representation for is
obtained using the memory-function technique for the relaxation function in
terms of the Hubbard operators, and the generalized Drude law is derived. The
relaxation rate due to the decay of charge excitations into particle-hole pairs
assisted by antiferromagnetic spin fluctuations is calculated in the
mode-coupling approximation. Using results for the spectral function of spin
excitations calculated previously, the relaxation rate and the optical and dc
conductivities are calculated in a broad region of doping and temperatures. The
reasonable agreement of the theory with experimental data for cuprates proves
the important role of spin-fluctuation scattering in the charge dynamics.Comment: 13 pages,15 figures, v.2, publication referenc
Thermal Duality and Hagedorn Transition from p-adic Strings
We develop the finite temperature theory of p-adic string models. We find
that the thermal properties of these non-local field theories can be
interpreted either as contributions of standard thermal modes with energies
proportional to the temperature, or inverse thermal modes with energies
proportional to the inverse of the temperature, leading to a "thermal duality"
at leading order (genus one) analogous to the well known T-duality of string
theory. The p-adic strings also recover the asymptotic limits (high and low
temperature) for arbitrary genus that purely stringy calculations have yielded.
We also discuss our findings surrounding the nature of the Hagedorn transition.Comment: 4 pages and 4 figure
Random Hierarchical Matrices: Spectral Properties and Relation to Polymers on Disordered Trees
We study the statistical and dynamic properties of the systems characterized
by an ultrametric space of states and translationary non-invariant symmetric
transition matrices of the Parisi type subjected to "locally constant"
randomization. Using the explicit expression for eigenvalues of such matrices,
we compute the spectral density for the Gaussian distribution of matrix
elements. We also compute the averaged "survival probability" (SP) having sense
of the probability to find a system in the initial state by time . Using the
similarity between the averaged SP for locally constant randomized Parisi
matrices and the partition function of directed polymers on disordered trees,
we show that for times (where is some critical
time) a "lacunary" structure of the ultrametric space occurs with the
probability . This means that the escape from some bounded
areas of the ultrametric space of states is locked and the kinetics is confined
in these areas for infinitely long time.Comment: 7 pages, 2 figures (the paper is essentially reworked
Application of Speckle Dynamics and Raman Light Scattering to Study the Fracture Features of Pipe Steel at High-cycle Fatigue
Despite a long history of research and a large number of publications, currently there are no methods for assessing and calculating the residual life of structural elements with their multi-cycle fatigue that would meet the requirements of engineering practice. In this regard, the role of physical methods to record the features of accumulation of local fatigue damage without stopping the operation or testing of various objects for fatigue increases. In the article two laser methods are used to study the origin of fatigue crack. Earlier, after testing for high-cycle fatigue of polished steel specimen with a Charpy notch, two zones of different sizes with different roughness were found near the notch. The first zone of 50x100 μm was located directly on the top of the notch. It consisted of inhomogeneities up to 10 μm in diameter and about 100 nm in height. In the center of the zone a macro-crack was discovered. The second zone with a diameter of 500-700 microns had a form of a hole (tie) with a depth of about 1 micron. Its center was located at a distance of 250-300 microns from the top of the notch. The aim of the work was to determine the formulation of inhomogeneities in a small zone and the sequence of the two zones’ occurrence. By using Raman microscopy, it is shown that the inhomogeneities are pieces of iron carbide. By the peculiarities of speckle image changes it is shown that the formation of two zones begins almost simultaneously. After the origination of a macro crack with a length of about 100 microns, a new plasticity zone at its top begins to form. Possible formation mechanisms of two zones are discussed. The disadvantages of the speckle method and the direction of further research are considered. © PNRPU.The authors thank I. S. Kamentsev, N.. Drukarenko, I. Tikhonova for help with sample preparation and fatigue testing. The work was carried out on the equipment of centers for collective use " Plastometry" of Institute of Engineering Science of Ural Branch of RAS and " Nanomaterials and Nanotechnology" of Ural Federal University with partial funding RFBR grant № 16-08-01077_a and act 211 of Government of the Russian Federation, agreement No. 02.A03.21.0006
Combined simulation of quasi-static deep drawing and electromagnetic forming by means of a coupled damage–viscoplasticity model at finite strains
The combination of quasi-static and electromagnetic pulse forming increases the
formability of sheet metal forming processes. A cooperation between the institute of
Applied Mechanics (IFAM) of the RWTH Aachen and the Institute of Forming Technology
and Lightweight Construction (IUL) of the TU Dortmund is investigating these processes
both experimentally and by simulation for the deep-drawing process of a cross-shaped
cup. Aim of the work is to show and prove that with this forming strategy we obtain a more
sharpened radius of the cup edges.The combined deformation process is simulated by
means of finite elements using a material model developed in [1,2]. A recently proposed
finite strain anisotropic viscoplastic model, taking combined nonlinear kinematic and
isotropic hardening into account, is coupled with ductile damage in the context of
continuum damage mechanics. For the simulation, the evolution equations for the internal
variables of the constitutive model are numerically integrated in an explicit manner and the
model is then implemented as a user material subroutine in the commercial finite element
package LS-Dyna
Nonlinear dynamics of large amplitude dust acoustic shocks and solitary pulses in dusty plasmas
We present a fully nonlinear theory for dust acoustic (DA) shocks and DA
solitary pulses in a strongly coupled dusty plasma, which have been recently
observed experimentally by Heinrich et al. [Phys. Rev. Lett. 103, 115002
(2009)], Teng et al. [Phys. Rev. Lett. 103, 245005 (2009)], and Bandyopadhyay
et al. [Phys. Rev. Lett. 101, 065006 (2008)]. For this purpose, we use a
generalized hydrodynamic model for the strongly coupled dust grains, accounting
for arbitrary large amplitude dust number density compressions and potential
distributions associated with fully nonlinear nonstationary DA waves.
Time-dependent numerical solutions of our nonlinear model compare favorably
well with the recent experimental works (mentioned above) that have reported
the formation of large amplitude non-stationary DA shocks and DA solitary
pulses in low-temperature dusty plasma discharges.Comment: 9 pages, 4 figures. To be published in Physical Review
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