Ak, Turgut; Aydemir, Tugba; Saha, Asit; Kara, Abdul Hamid
2018-06-01
Propagation of nonlinear shock waves for the generalised Oskolkov equation and dynamic motions of the perturbed Oskolkov equation are investigated. Employing the unified method, a collection of exact shock wave solutions for the generalised Oskolkov equations is presented. Collocation finite element method is applied to the generalised Oskolkov equation for checking the accuracy of the proposed method by two test problems including the motion of shock wave and evolution of waves with Gaussian and undular bore initial conditions. Considering an external periodic perturbation, the dynamic motions of the perturbed generalised Oskolkov equation are studied depending on the system parameters with the help of phase portrait and time series plot. The perturbed generalised Oskolkov equation exhibits period-3, quasiperiodic and chaotic motions for some special values of the system parameters, whereas the generalised Oskolkov equation presents shock waves in the absence of external periodic perturbation.
Bolshije planõ znamenitõh kinorezhissjorov. Nikita Mihhalkov snimet tri filma
2005-01-01
Režissöör Nikita Mihhalkov alustas tööd kaheosalise projektiga ühisnimetuse all "Päikesest rammestunud 2", valmistub filmima remake'i Sidney Lumet' filmist "12 vihast meest" ja tema stuudio "Trite" ostis ekraniseerimisõigused B. Akunini romaanile "Spiooniromaan"
New exact solutions of the generalized Zakharov–Kuznetsov ...
In this paper, new exact solutions, including soliton, rational and elliptic integral function solutions, for the generalized Zakharov–Kuznetsov modified equal-width equation are obtained using a new approach called the extended trial equation method. In this discussion, a new version of the trial equation method for the ...
Mathematical analysis of Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation
Rozanova-Pierrat , Anna
2006-01-01
We consider the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation (ut — uux — βuxx)x— γΔy u = 0 in Sobolev spaces of functions periodic in x and with mean value zero. The derivation of KZK from the nonlinear isentropic Navier Stokes equations and the approximation of their solutions (for viscous and non viscous cases), the results of the existence, uniqueness, stability and blow-up of solution of KZK equation are obtained, also a result of existence of a smooth solution of Navier-Stokes system i...
Lie symmetries of a generalized Kuznetsov-Zabolotskaya-Khoklov equation
Gungor, F.; Ozemir, C.
2014-01-01
We consider a class of generalized Kuznetsov--Zabolotskaya--Khokhlov (gKZK) equations and determine its equivalence group, which is then used to give a complete symmetry classification of this class. The infinite-dimensional symmetry is used to reduce such equations to (1+1)-dimensional PDEs. Special attention is paid to group-theoretical properties of a class of generalized dispersionless KP (gdKP) or Zabolotskaya--Khokhlov equations as a subclass of gKZK equations. The conditions are determ...
Multi-symplectic Preissmann methods for generalized Zakharov-Kuznetsov equation
Wang Junjie; Yang Kuande; Wang Liantang
2012-01-01
Generalized Zakharov-Kuznetsov equation, a typical nonlinear wave equation, was studied based on the multi-symplectic theory in Hamilton space. The multi-symplectic formulations of generalized Zakharov-Kuznetsov equation with several conservation laws are presented. The multi-symplectic Preissmann method is used to discretize the formulations. The numerical experiment is given, and the results verify the efficiency of the multi-symplectic scheme. (authors)
Kuznetsov-Ma waves train generation in a left-handed material
Atangana, Jacques; Giscard Onana Essama, Bedel; Biya-Motto, Frederick; Mokhtari, Bouchra; Cherkaoui Eddeqaqi, Noureddine; Crépin Kofane, Timoléon
2015-03-01
We analyze the behavior of an electromagnetic wave which propagates in a left-handed material. Second-order dispersion and cubic-quintic nonlinearities are considered. This behavior of an electromagnetic wave is modeled by a nonlinear Schrödinger equation which is solved by collective coordinates theory in order to characterize the light pulse intensity profile. More so, a specific frequency range has been outlined where electromagnetic wave behavior will be investigated. The perfect combination of second-order dispersion and cubic nonlinearity leads to a robust soliton. When the quintic nonlinearity comes into play, it provokes strong and long internal perturbations which lead to Benjamin-Feir instability. This phenomenon, also called modulational instability, induces appearance of a Kuznetsov-Ma waves train. We numerically verify the validity of Kuznetsov-Ma theory by presenting physical conditions which lead to Kuznetsov-Ma waves train generation. Thereafter, some properties of such waves train are also verified.
M. Arshad
Full Text Available In this manuscript, we constructed different form of new exact solutions of generalized coupled Zakharov–Kuznetsov and dispersive long wave equations by utilizing the modified extended direct algebraic method. New exact traveling wave solutions for both equations are obtained in the form of soliton, periodic, bright, and dark solitary wave solutions. There are many applications of the present traveling wave solutions in physics and furthermore, a wide class of coupled nonlinear evolution equations can be solved by this method. Keywords: Traveling wave solutions, Elliptic solutions, Generalized coupled Zakharov–Kuznetsov equation, Dispersive long wave equation, Modified extended direct algebraic method
Lu, Dianchen; Seadawy, A. R.; Arshad, M.; Wang, Jun
In this paper, new exact solitary wave, soliton and elliptic function solutions are constructed in various forms of three dimensional nonlinear partial differential equations (PDEs) in mathematical physics by utilizing modified extended direct algebraic method. Soliton solutions in different forms such as bell and anti-bell periodic, dark soliton, bright soliton, bright and dark solitary wave in periodic form etc are obtained, which have large applications in different branches of physics and other areas of applied sciences. The obtained solutions are also presented graphically. Furthermore, many other nonlinear evolution equations arising in mathematical physics and engineering can also be solved by this powerful, reliable and capable method. The nonlinear three dimensional extended Zakharov-Kuznetsov dynamica equation and (3 + 1)-dimensional modified KdV-Zakharov-Kuznetsov equation are selected to show the reliability and effectiveness of the current method.
A polynomial expansion method and its application in the coupled Zakharov-Kuznetsov equations
Huang Wenhua
2006-01-01
A polynomial expansion method is presented to solve nonlinear evolution equations. Applying this method, the coupled Zakharov-Kuznetsov equations in fluid system are studied and many exact travelling wave solutions are obtained. These solutions include solitary wave solutions, periodic solutions and rational type solutions
A note on the convergence of the Zakharov-Kuznetsov equation by homotopy analysis method
Amir Fallahzadeh
2014-07-01
Full Text Available In this paper, the convergence of Zakharov-Kuznetsov (ZK equation by homotopy analysis method (HAM is investigated. A theorem is proved to guarantee the convergence of HAMand to find the series solution of this equation via a reliable algorithm.
Controllability of the moments for Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation
Rozanova-Pierrat , Anna
2006-01-01
Recalling the proprieties of the Khokhlov-Zabolotskaya-Kuznetsov(KZK) equation, we prove the controllability of moments result for the linear part of KZK equation. Then we prove the local controllability result for the full KZK equation applying a known method of perturbation for the nonlinear inverse problem.
Different physical structures of solutions for two related Zakharov-Kuznetsov equations
Lai Shaoyong; Yin Jun; Wu Yonghong
2008-01-01
The auxiliary differential equation approach and the symbolic computation system Maple are employed to investigate two types of related Zakharov-Kuznetsov equations with variable coefficients. The exact solutions to the equations are constructed analytically under certain circumstances. It is shown that the variable coefficients of the derivative terms of the equations result in their semi-travelling wave solutions
Papandreou, Elena
2014-01-01
This dissertation puts the spotlight on the music of Nikita Koshkin (b. 1956)—Russia’s most important composer for guitar and one of the world’s leading composers for the instrument—and, in particular, his ‘Megaron’ Concerto for guitar and string orchestra, composed in 2005 and premiered in 2006 by this author. Performance issues are discussed in detail, in an innately practical manner, so that the guitarist who wishes to perform this work will have enough information to assist him. Moreover,...
Inc, Mustafa
2007-01-01
In this paper, the nonlinear dispersive Zakharov-Kuznetsov ZK(m, n, k) equations are solved exactly by using the Adomian decomposition method. The two special cases, ZK(2, 2, 2) and ZK(3, 3, 3), are chosen to illustrate the concrete scheme of the decomposition method in ZK(m, n, k) equations. General formulas for the solutions of ZK(m, n, k) equations are established
Explicit Solutions for Generalized (2+1)-Dimensional Nonlinear Zakharov-Kuznetsov Equation
Sun Yuhuai; Ma Zhimin; Li Yan
2010-01-01
The exact solutions of the generalized (2+1)-dimensional nonlinear Zakharov-Kuznetsov (Z-K) equation are explored by the method of the improved generalized auxiliary differential equation. Many explicit analytic solutions of the Z-K equation are obtained. The methods used to solve the Z-K equation can be employed in further work to establish new solutions for other nonlinear partial differential equations. (general)
Biswas, Anjan
2009-01-01
In this Letter, the 1-soliton solution of the Zakharov-Kuznetsov equation with power law nonlinearity and nonlinear dispersion along with time-dependent coefficients is obtained. There are two models for this kind of an equation that are studied. The constraint relation between these time-dependent coefficients is established for the solitons to exist. Subsequently, this equation is again analysed with generalized evolution. The solitary wave ansatz is used to carry out this investigation.
Shilei Liu; Yanye Yang; Chenghai Li; Xiasheng Guo; Juan Tu; Dong Zhang
2018-01-01
High intensity focused ultrasound (HIFU) has been proven to be promising in non-invasive therapies, in which precise prediction of the focused ultrasound field is crucial for its accurate and safe application. Although the Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation has been widely used in the calculation of the nonlinear acoustic field of HIFU, some deviations still exist when it comes to dispersive medium. This problem also exists as an obstacle to the Westervelt model and the Spherical ...
Dynamic behavior of the quantum Zakharov-Kuznetsov equations in dense quantum magnetoplasmas
Zhen, Hui-Ling; Tian, Bo, E-mail: tian-bupt@163.com; Wang, Yu-Feng; Zhong, Hui; Sun, Wen-Rong [State Key Laboratory of Information Photonics and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China)
2014-01-15
Quantum Zakharov-Kuznetsov (qZK) equation is found in a dense quantum magnetoplasma. Via the spectral analysis, we investigate the Hamiltonian and periodicity of the qZK equation. Using the Hirota method, we obtain the bilinear forms and N-soliton solutions. Asymptotic analysis on the two-soliton solutions shows that the soliton interaction is elastic. Figures are plotted to reveal the propagation characteristics and interaction between the two solitons. We find that the one soliton has a single peak and its amplitude is positively related to H{sub e}, while the two solitons are parallel when H{sub e} < 2, otherwise, the one soliton has two peaks and the two solitons interact with each other. Hereby, H{sub e} is proportional to the ratio of the strength of magnetic field to the electronic Fermi temperature. External periodic force on the qZK equation yields the chaotic motions. Through some phase projections, the process from a sequence of the quasi-period doubling to chaos can be observed. The chaotic behavior is observed since the power spectra are calculated, and the quasi-period doubling states of perturbed qZK equation are given. The final chaotic state of the perturbed qZK is obtained.
Soliton solutions of the quantum Zakharov-Kuznetsov equation which arises in quantum magneto-plasmas
Sindi, Cevat Teymuri; Manafian, Jalil
2017-02-01
In this paper, we extended the improved tan(φ/2)-expansion method (ITEM) and the generalized G'/G-expansion method (GGEM) proposed by Manafian and Fazli (Opt. Quantum Electron. 48, 413 (2016)) to construct new types of soliton wave solutions of nonlinear partial differential equations (NPDEs). Moreover, we use of the improvement of the Exp-function method (IEFM) proposed by Jahani and Manafian (Eur. Phys. J. Plus 131, 54 (2016)) for obtaining solutions of NPDEs. The merit of the presented three methods is they can find further solutions to the considered problems, including soliton, periodic, kink, kink-singular wave solutions. This paper studies the quantum Zakharov-Kuznetsov (QZK) equation by the aid of the improved tan(φ/2)-expansion method, the generalized G'/G-expansion method and the improvement of the Exp-function method. Moreover, the 1-soliton solution of the modified QZK equation with power law nonlinearity is obtained by the aid of traveling wave hypothesis with the necessary constraints in place for the existence of the soliton. Comparing our new results with Ebadi et al. results (Astrophys. Space Sci. 341, 507 (2012)), namely, G'/G-expansion method, exp-function method, modified F-expansion method, shows that our results give further solutions. Finally, these solutions might play an important role in engineering, physics and applied mathematics fields.
"Rollingi" zazhgli Berlin / Nikita Kartsev
Kartsev, Nikita
2008-01-01
58. Berlinale avatseremoonialt. Avafilmiks Martin Scorsese dokumentaalfilm "Shine a Light" inglise ansamblist Rolling Stones. Lisatud lõike sellele järgnenud pressikonverentsilt, kus sõna said nii režissöör kui ansambliliikmed
Şenol, Mehmet; Alquran, Marwan; Kasmaei, Hamed Daei
2018-06-01
In this paper, we present analytic-approximate solution of time-fractional Zakharov-Kuznetsov equation. This model demonstrates the behavior of weakly nonlinear ion acoustic waves in a plasma bearing cold ions and hot isothermal electrons in the presence of a uniform magnetic field. Basic definitions of fractional derivatives are described in the Caputo sense. Perturbation-iteration algorithm (PIA) and residual power series method (RPSM) are applied to solve this equation with success. The convergence analysis is also presented for both methods. Numerical results are given and then they are compared with the exact solutions. Comparison of the results reveal that both methods are competitive, powerful, reliable, simple to use and ready to apply to wide range of fractional partial differential equations.
Cuevas-Maraver, J.; Malomed, Boris A.; Kevrekidis, P. G.; Frantzeskakis, D. J.
2018-04-01
We demonstrate a possibility to make rogue waves (RWs) in the form of the Peregrine soliton (PS) and Kuznetsov-Ma breathers (KMBs) effectively stable objects, with the help of properly defined dispersion or nonlinearity management applied to the continuous-wave (CW) background supporting the RWs. In particular, it is found that either management scheme, if applied along the longitudinal coordinate, making the underlying nonlinear Schrödinger equation (NLSE) self-defocusing in the course of disappearance of the PS, indeed stabilizes the global solution with respect to the modulational instability of the background. In the process, additional excitations are generated, namely, dispersive shock waves and, in some cases, also a pair of slowly separating dark solitons. Further, the nonlinearity-management format, which makes the NLSE defocusing outside of a finite domain in the transverse direction, enables the stabilization of the KMBs, in the form of confined oscillating states. On the other hand, a nonlinearity-management format applied periodically along the propagation direction, creates expanding patterns featuring multiplication of KMBs through their cascading fission.
Shilei Liu
2018-04-01
Full Text Available High intensity focused ultrasound (HIFU has been proven to be promising in non-invasive therapies, in which precise prediction of the focused ultrasound field is crucial for its accurate and safe application. Although the Khokhlov–Zabolotskaya–Kuznetsov (KZK equation has been widely used in the calculation of the nonlinear acoustic field of HIFU, some deviations still exist when it comes to dispersive medium. This problem also exists as an obstacle to the Westervelt model and the Spherical Beam Equation. Considering that the KZK equation is the most prevalent model in HIFU applications due to its accurate and simple simulation algorithms, there is an urgent need to improve its performance in dispersive medium. In this work, a modified KZK (mKZK equation derived from a fractional order derivative is proposed to calculate the nonlinear acoustic field in a dispersive medium. By correcting the power index in the attenuation term, this model is capable of providing improved prediction accuracy, especially in the axial position of the focal area. Simulation results using the obtained model were further compared with the experimental results from a gel phantom. Good agreements were found, indicating the applicability of the proposed model. The findings of this work will be helpful in making more accurate treatment plans for HIFU therapies, as well as facilitating the application of ultrasound in acoustic hyperthermia therapy.
Qiao, Shan; Jackson, Edward; Coussios, Constantin C; Cleveland, Robin O
2016-09-01
Nonlinear acoustics plays an important role in both diagnostic and therapeutic applications of biomedical ultrasound and a number of research and commercial software packages are available. In this manuscript, predictions of two solvers available in a commercial software package, pzflex, one using the finite-element-method (FEM) and the other a pseudo-spectral method, spectralflex, are compared with measurements and the Khokhlov-Zabolotskaya-Kuznetsov (KZK) Texas code (a finite-difference time-domain algorithm). The pzflex methods solve the continuity equation, momentum equation and equation of state where they account for nonlinearity to second order whereas the KZK code solves a nonlinear wave equation with a paraxial approximation for diffraction. Measurements of the field from a single element 3.3 MHz focused transducer were compared with the simulations and there was good agreement for the fundamental frequency and the harmonics; however the FEM pzflex solver incurred a high computational cost to achieve equivalent accuracy. In addition, pzflex results exhibited non-physical oscillations in the spatial distribution of harmonics when the amplitudes were relatively low. It was found that spectralflex was able to accurately capture the nonlinear fields at reasonable computational cost. These results emphasize the need to benchmark nonlinear simulations before using codes as predictive tools.
Kumar Samanta, Utpal; Saha, Asit; Chatterjee, Prasanta
2013-01-01
Bifurcations of nonlinear propagation of ion acoustic waves (IAWs) in a magnetized plasma whose constituents are cold ions and kappa distributed electron are investigated using a two component plasma model. The standard reductive perturbation technique is used to derive the Zakharov-Kuznetsov (ZK) equation for IAWs. By using the bifurcation theory of planar dynamical systems to this ZK equation, the existence of solitary wave solutions and periodic travelling wave solutions is established. All exact explicit solutions of these travelling waves are determined. The results may have relevance in dense space plasmas
Rjazanov võpustil "Andersena" / Nikita Kartsev
Kartsev, Nikita
2006-01-01
Vene režissööril Eldar Rjazanovil esilinastus Moskva kinomajas eluloofilm muinasjutuvestja Hans Christian Anderseni elust "Andersen. Elu ilma armastuseta" ("Andersen. Zhizn bez ljubvi"). Stsenaarium valmis Rjazanovil koostöös Irakli Kvirikadzega, operaatorid olid Jevgeni Guslinski ja Vadim Alissov, helilooja Aleksei Rõbnikov. Nimiosas on kolm näitlejat - Vanja Haratjan, Stass Rjadinski, Sergei Migitsko
Zhen, Hui-Ling; Tian, Bo, E-mail: tian-bupt@163.com; Wang, Yu-Feng; Sun, Wen-Rong; Liu, Li-Cai [State Key Laboratory of Information Photonics and Optical Communications, and School of Science, Beijing University of Posts and Telecommunications, Beijing 100876 (China)
2014-07-15
The extended Zakharov-Kuznetsov (eZK) equation for the magnetized two-ion-temperature dusty plasma is studied in this paper. With the help of Hirota method, bilinear forms and N-soliton solutions are given, and soliton propagation is graphically analyzed. We find that the soliton amplitude is positively related to the nonlinear coefficient A, while inversely related to the dispersion coefficients B and C. We obtain that the soliton amplitude will increase with the mass of the jth dust grain and the average charge number residing on the dust grain decreased, but the soliton amplitude will increase with the equilibrium number density of the jth dust grain increased. Upon the introduction of the periodic external forcing term, both the weak and developed chaotic motions can occur. Difference between the two chaotic motions roots in the inequality between the nonlinear coefficient l{sub 2} and perturbed term h{sub 1}. The developed chaos can be weakened with B or C decreased and A increased. Periodic motion of the perturbed eZK equation can be observed when there is a balance between l{sub 2} and h{sub 1}.
Du, Xia-Xia; Tian, Bo; Chai, Jun; Sun, Yan; Yuan, Yu-Qiang
2017-11-01
In this paper, we investigate a (3+1)-dimensional modified Zakharov-Kuznetsov equation, which describes the nonlinear plasma-acoustic waves in a multicomponent magnetised plasma. With the aid of the Hirota method and symbolic computation, bilinear forms and one-, two- and three-soliton solutions are derived. The characteristics and interaction of the solitons are discussed graphically. We present the effects on the soliton's amplitude by the nonlinear coefficients which are related to the ratio of the positive-ion mass to negative-ion mass, number densities, initial densities of the lower- and higher-temperature electrons and ratio of the lower temperature to the higher temperature for electrons, as well as by the dispersion coefficient, which is related to the ratio of the positive-ion mass to the negative-ion mass and number densities. Moreover, using the Lie symmetry group theory, we derive the Lie point symmetry generators and the corresponding symmetry reductions, through which certain analytic solutions are obtained via the power series expansion method and the (G'/G) expansion method. We demonstrate that such an equation is strictly self-adjoint, and the conservation laws associated with the Lie point symmetry generators are derived.
"Zolotoi Oven" ishtshet svojego obladatelja / Valeri Kuznetsov
Kuznetsov, Valeri
2003-01-01
Parima filmi auhinnale "Zolotoi Oven" võistlevad Andrei Zvjagintsevi "Tagasitulek" ("Vozvrashtshenije"), Vadim Abdrashitovi "Magnettormid" ("Magnitnõje buri"), Gennadi Sidorovi "Vanaeided" ("Staruhhi") ja Pjotr Buslovi "Bumer"
Additive functionals and excursions of Kuznetsov processes
Hacène Boutabia
2005-01-01
semigroup of transition. In this paper, we give the excursion laws of (Xtt∈ℝ+ conditioned on the strict past and future without duality hypothesis. We study excursions of a general regenerative system and of a regenerative system consisting of the closure of the set of times the regular points of B are visited. In both cases, those conditioned excursion laws depend only on two points Xg− and Xd, where ]g,d[ is an excursion interval of the regenerative set M. We use the (FDt-predictable exit system to bring together the isolated points of M and its perfect part and replace the classical optional exit system. This has been a subject in literature before (e.g., Kaspi (1988 under the classical duality hypothesis. We define an “additive functional” for (Ytt∈ℝ with B, we generalize the laws cited before to (Ytt∈ℝ, and we express laws of pairs of excursions.
Nikita Il'ič Tolstoj: K 90-letiju so dnja roždenija
Plotnikova Anna A.
2015-01-01
Full Text Available V svjazi s 90-letiem akademika Nikity Il'iča Tolstogo v 2013 godu v ego čest' v Rossii, Serbii i Avstrii prošli slavističeskie konferencii, organizovannye spodvižnikami i učenikami velikogo filologa. Očerk posvjaščen žizni, dejatel'nosti i osnovnoj problematike etnolingvističeskih i fol'klornyh rabot Nikity Il'iča Tolstogo.
New exact solutions of the generalized Zakharov–Kuznetsov ...
years, Liu and other researchers developed the trial equation method and its ... soliton, elliptic integral function and Jacobi elliptic function solutions. ... nonlinearity parameter, is a positive real number. ..... reduce to rational function solution.
Khokhlov Zabolotskaya Kuznetsov type equation: nonlinear acoustics in heterogeneous media
Kostin, Ilya; Panasenko, Grigory
2006-04-01
The KZK type equation introduced in this Note differs from the traditional form of the KZK model known in acoustics by the assumptions on the nonlinear term. For this modified form, a global existence and uniqueness result is established for the case of non-constant coefficients. Afterwards the asymptotic behaviour of the solution of the KZK type equation with rapidly oscillating coefficients is studied. To cite this article: I. Kostin, G. Panasenko, C. R. Mecanique 334 (2006).
Simyar, Farhad; Osuji, Louis
2015-01-01
In the face of stiff completion for scarce funds to effectively navigate the affairs of business schools, college deans have to come up with strategic plans to ensure that various opinions and inputs of stake holders including faculty and staff are accommodated. Additionally, such deans are expected to come up with goals and objectives designed to…
Raamat uue maailma põliselanike päritolust / Nikolay Kuznetsov
Kuznetsov, Nikolay
2008-01-01
Arvustus: Березкин Ю. Е. Мифы заселяют Америку : Ареальное распределение фольклорных мотивов и ранние миграции в Новый Свет. Москва : Объединенное гуманитарное издательство, 2007
Uurali mütoloogiate avaköide tutvustab komide maailmapilti / Nikolay Kuznetsov
Kuznetsov, Nikolay
2006-01-01
Arvustus: Komi Mythology : Encyclopaedia of Uralic Mythologies. 1. / toim. Vladimir Napolskikh, Anna-Leena Siikala, Mihály Hoppál. Budapest : Akadémiai Kiadó ; Helsinki : Finnish Literature Society, 2003
Islam, Md Hamidul; Khan, Kamruzzaman; Akbar, M Ali; Salam, Md Abdus
2014-01-01
Mathematical modeling of many physical systems leads to nonlinear evolution equations because most physical systems are inherently nonlinear in nature. The investigation of traveling wave solutions of nonlinear partial differential equations (NPDEs) plays a significant role in the study of nonlinear physical phenomena. In this article, we construct the traveling wave solutions of modified KDV-ZK equation and viscous Burgers equation by using an enhanced (G '/G) -expansion method. A number of traveling wave solutions in terms of unknown parameters are obtained. Derived traveling wave solutions exhibit solitary waves when special values are given to its unknown parameters. 35C07; 35C08; 35P99.
Rozanova-Pierrat, Anna
2009-01-01
We consider the derivation of the Khokhlov-Zabolotskaya-Kuznetzov (KZK) equation from the nonlinear isentropic Navier-Stokes and Euler systems. The KZK equation is a mathematical model that describes the nonlinear propagation of a finite-amplitude sound pulse in a thermo-viscous medium. The derivation of the KZK equation has to date been based on the paraxial approximation of small perturbations around a given state of the Navier-Stokes system. However, this method does not ...
Kärk, Lauri, 1954-
1996-01-01
Anton Tšehhovi - Aleksandr Adabashjani - Nikita Mihhalkovi 'Pianoola ehk Mehhaaniline klaver' Tallinna Linnateatris, lav. E. Nüganen. Võrdlus N. Mihhalkovi filmiga 'Lõpetamata pala pianoolale' (1977)
Zaika, N I; Kibkalo, Yu V; Parlag, O A; Sikora, D I; Tokarev, V P; Shityuk, V A [AN Ukrainskoj SSR, Kiev (Ukrainian SSR). Inst. Yadernykh Issledovanij
1989-04-01
Two-parameter measurements of the mass and energy distributions of fission products in the fission of {sup 232}Th by 21.0-26.4 MeV {alpha}-particles (h=1 MeV) are conducted using the correlation method. The obtained results show that in the region under investigation the average total kinetic energies of the fission products E-bar{sub k} have no noticeable variations within the experimental error of {plus minus} 1.5 MeV and the dispersion {sigma}{sup 2}E{sub k} slowly increases. For the E-bar{sub k} mass dependence of heavy fraction the maximum is observed at A=132, that confirms a hypothesis on the influence of the closed-shell effects at the magic numbers of Z=50 and N=82. Assuming the existence of different barrier values for two models of the fission the ratio of symmetric and asymmetric fission yields are analyzed in the statistical model. It is shown that the barrier difference for two modes of fission is 1.3-1.4 MeV, which is in good agreement with the model of two fission modes.
Resonance – Journal of Science Education | Indian Academy of ...
Home; Journals; Resonance – Journal of Science Education. Nikita Agarwal. Articles written in Resonance – Journal of Science Education. Volume 23 Issue 3 March 2018 pp 253-262 General Article. Maryam Mirzakhani: The Master Artist of Curved Surfaces · Nikita Agarwal Riddhi Shah Geetha Venkataraman.
Jeltsova, Aljona
2005-01-01
Sisu: "Üks, tuks. Sjoo elo om - tuks..." ; "Ammuq lännüq pilveq - luigaq..." ; "Ma üles märki laulu jovva-õs..." ; Sukka mi ; "Täämbä üüse om taivah üts täht..." ; "Ma tulõ viirde uma süäme jäti..."
Zimina Nina
2013-06-01
Full Text Available The article concerns the activity of the St. Petersburg Department of the Moscow Society for Religious education, targeted to give the western Christians the knowledge about the affairs’ state of the Eastern Church. The author identifies the literature published and translated by Russian theologians and members of clergy for western Christians from 1871 to 1880. She describes the work’s methods of the Department. The response of western theologians was the publication of works about the Eastern Church. Members of the St. Petersburg Department managed to fulfill designated tasks despite the short period of activity. They illuminated as much as possible the state of the contemporary Church, a church history and theology and assisted western and east Christians in the dialog’s development.
Putin predlozhil Nikite rabotu / Anna Skvortsova
Skvortsova, Anna
2001-01-01
Moskva XXIII rahvusvahelise filmifestivali külaliseks olnud Hollywoodi kuulsused Jack Nicholson, Sean Penn ja mitmed teised tuntud vene ja välismaa filmiinimesed kohtusid Venemaa presidendi Vladimir Putiniga Nikita Mihhalkovi suvilas
Annals of African Surgery - Vol 14, No 2 (2017)
Validation of the Euroscore on Cardiac Surgery Patients in Nairobi · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Awori Mark, Mehta Nikita, Mitema Fred, Mwangi Jimmy, Mjahid Hassan, Oloo Paul ...
2007-01-01
Augustis Vene Teatri alternatiivsel laval "Garaaž" : 9. augustil "Veerevad kivid ei sammaldu", lavastaja Nikita Grinshpun (Moskva) ja 7., 8. augustil Aleksandr Potuzhnõi lavastus "Jõgi asfaldil", autor Dmitri Lipskerov
Dvenadtsat muzhtshin ohhotjatsja za lvom / Vladimir Barsegjan
Barsegjan, Vladimir
2007-01-01
Režissöör Nikita Mihhalkov osaleb Veneetsia 64. filmifestivalil oma uue filmiga "12", mis on Sidney Lumet' kuulsa filmi "12 vihast meest" ("12 Angry Men" : Ameerika Ühendriigid 1957) omapärane uusversioon
Zaarkanit li "Mongol" "Oskara"? / Boris Tuch
Tuch, Boris, 1946-
2008-01-01
Nikita Mihhalkovi mängufilm "12" on Venemaa poolt võõrfilmi Oscari kandidaat, Kasahstani poolt aga "Mongol", mille režissöör on samuti venelane Sergei Bodrov. Põhjalik arvustus viimasest filmist
Déjà vu: supermän draakoni hammaste vahel / Neeme Raud
Raud, Neeme, 1969-
2009-01-01
Autor analüüsib USA prsidendi Barack Obama visiiti Hiinasse ning kohtumist presidendi Hu Jintaoga, mis sarnanes suuresti president John F. Kennedy esimese kohtumisega NSV Liidu liidri Nikita Hruštšoviga
Семью Михалковых оболгали? / подготовила Анна Велигжанина
2004-01-01
Komsomolskaja Pravda v Baltii kuupäevad on 10.-17. sept. 2004. Aleksandr Tšervinski raamatust "Шишкин Лес", mille prototüüpideks on Sergei ja Nikita Mihhalkov ning Andron Kontšalovski. Intervjuud raamatu autori ja Sergei Mihhalkoviga, lühiintervjuud Nikita Mihhalkovi ja Andron Kontšalovskiga
Российский Огюст Перре: к 100-летию «Корпуса мастерских Строгановского училища»
НАЩОКИНА МАРИЯ ВЛАДИМИРОВНА
2015-01-01
This paper shows work of architect A.V. Kuznetsov (1874-1954) in connection with his experiences and achievements in the construction of reinforced concrete buildings. On the basis of comparative studies of his work and creativity of the European pioneer of reinforced concrete construction A. Perret shows the fundamental significance Kuznetsov''s theoretical works and completed buildings for introduction of new materials, constructions and technologies in domestic architectural practice. It i...
Cold War Kitchen: Americanization, Technology, and European users
Oldenziel, R.; Zachmann, K.
2009-01-01
Richard Nixon and Nikita Khrushchev's famous "kitchen debate" in 1958 involved more than the virtues of American appliances. Both Nixon and Khrushchev recognized the political symbolism of the modern kitchen; the kind of technological innovation represented in this everyday context spoke to the
A tragic early death has stopped potential revealing knowledge on doping in Russia
Christiansen, Ask Vest; Gleaves, John
2016-01-01
On 14 February 2016, Nikita Kamaev died of a “massive heart attack”. Kamaev was the executive director of Russia's anti-doping agency, RUSADA, from 2011 to 2015. His death came 10 weeks after he stepped down as head of RUSADA since he knew that he could not continue on the post after WADA on 18...
Vene eliidi mõõdupuu : kuidas suhtute Võssotskisse?
1999-01-01
Sisu: Carindowsky, Emilie. [Vladimir Võssotski] ; Võssotski, Nikita. Kuulsa lauliku poeg taunib isa jumaldajaid / üles kirjut. Raul Ratman ; Simagin, Rudolf. Elu lõppes ja laat algas / üles kirjut. Raul Ratman. Tallinlasel Rudolf Simaginil on V. Võssotski materjalide kogu
Vzgljad s obeihh storon ekrana : obrushivshiisja most / Boris Tuch
Тух, Борис, 1946-
2007-01-01
Vene telekanali Pervõi Kanal Tallinn-Moskva telesillana vormistatud poliitiline väitlussaade "Otsustage ise" 18. jaanuaril, kus Eesti poolt esindasid Riigikogu liige Raivo Järvi ja Eesti saadik Moskvas Marina Kaljurand, Moskvat teiste seas ka Nikita Mihhalkov
Vladimir Võssotski : planeta? ulitsa? tsvetok! / Deniss Ushakov
Ushakov, Deniss
2008-01-01
Vladimir Võssotski 70. sünniaastapäeva puhul meenutatakse viise, kuidas on püütud ja püütakse jäädvustada tema mälestust (raamatud, näitused, muuseumid, ausambad, tänavad jne). Sõna saavad ka poeg Nikita Võssotski ja teine abikaasa Ljudmila Abramova
78 FR 57927 - Credit Risk Retention
2013-09-20
..., Division of Research & Statistics, (202) 452-2342; or Nikita Pastor, Counsel, (202) 452-3667, Division of... include provisions that strengthen the regulation and supervision of national recognized statistical... delinquencies and foreclosures since 2007. These included features permitting negative amortization, interest...
2006-01-01
Režissöör Nikita Mihhalkov lõpetas Sidney Lumet filmi "12 vihast meest" uusversiooni filmivõtted. Järgmisena kavatseb ta filmistsenaariumi järgi lavastada ka teatris sama näitlejate koosseisuga lavastuse
Home; Journals; Resonance – Journal of Science Education. Riddhi Shah. Articles written in Resonance – Journal of Science Education. Volume 23 Issue 3 March 2018 pp 253-262 General Article. Maryam Mirzakhani: The Master Artist of Curved Surfaces · Nikita Agarwal Riddhi Shah Geetha Venkataraman · More Details ...
"Nika" s mongolo-kazahskim aktsentom / Boris Tuch
Tuch, Boris, 1946-
2008-01-01
Venemaa filmiauhinna "Nika" võitis Sergei Bodrovi mängufilm "Mongol". Aleksandr Sokurov, Nikita Mihhalkov ja Vladimir Hotinenko ei lubanud oma filme auhindamisele esitada. Vastuoludest teise vene kinoakadeemia auhinna "Kuldne Kotkas" komiteega ning võõrfilmi Oscari mittemääramisest sel aastal Vene filmidele
Filmõ Mihhalkova i Bodrova nominirovanõ na premiju "Oskar"
2008-01-01
Nikita Mihhalkovi mängufilm "12" on Venemaa poolt võõrfilmi Oscari kandidaat, Kasahstani poolt aga "Mongol", mille režissöör on samuti venelane Sergei Bodrov. Mõlemad on valitud 9 filmi hulka, millest 22.01. nomineeritakse viis
Pelevini ja Bulgakovi mängib üle Tšernobõl / Jaanus Piirsalu
Piirsalu, Jaanus, 1973-
2011-01-01
Venemaal ekraanile jõudnud Viktor Ginzburgi filmist "Generation "P"" ja Juri Kara filmist "Meister ja Margarita" (1994). Tšernobõli tuumajaama katastroofist rääkivast Aleksandr Mindadze filmist "Laupäeval". Peatselt valmib film Vladimir Võssotskist. Stsenaariumi on kirjutanud Nikita Võssotski
Russia’s Counterinsurgency in North Caucasus: Performance and Consequences
2014-03-01
Buddhist mon- asteries of the Kalmyks, and murdered or imprisoned the lamas . After Nikita Khrushchev’s recognition of Stalin’s atrocities and the “cult of...www.circassianworld.com/pdf/Henze_ Islam_NorthCaucasus.pdf. 9. A. A. Alov and N. G. Vladimirov, “Rasprostranenie Is- lama sredi narodov Severnogo Kavkaza v VIII-XVIII
Poeetilised prantslased / Kristiina Davidjants
Davidjants, Kristiina, 1974-
2007-01-01
French Connection : Prantsuse kino "The American Way" - Prantsuse filmikunsti suurteosed ja nende Ameerika uusversioonid kinos Sõprus 28. maist 1. juunini. Lähemalt filmidest "Pepe le Moko" (Julien Duvivier, 1937), "Metslane" (Jean Renoir, 1938), "Viimasel hingetõmbel" (Jean-Luc Godard, 1959), "Uppumissurmast päästetud Boudu" (Jean Renoir, 1932), "Naine nimega Nikita" (Luc Besson, 1990)
Vene Kultuurikeskus = The Russian Culture Centre / Margit Mutso
Mutso, Margit, 1966-
2010-01-01
Tallinnas Mere puiestee 5 asuva hoone (arhitekt A. Kuznetsov, 1954) restaureerimisest. Arhitekt Niina Mäger, sisearhitekt Anne Tamverk. Ajaloolane Aleksandr Pantelejev. Žürii liikme Mait Summataveti hinnang kultuurkapitali aastapreemiale esitatud hoonele
Andrei Mironov povzdoril s verbljudom iz-za odekolona / Viktoria Volkova
Volkova, Viktoria
2006-01-01
Tegijate meenutusi, kuidas sündis seiklusfilm "Vabariigi vara" ("Dostojanije respubliki") : režissöör Vladimir Bõtshkov : stsenarist Issai Kuznetsov : näitlejad Andrei Mironov jt. : Nõukogude Liit 1971
Classification of single travelling wave solutions to the generalized ...
Kuznetsov equation. JIN-YAN HU. Department of Mathematics, Northeast Petroleum University, Daqing 163318, China. E-mail: hujinyan_Alice@163.com; 13836955068@163.com. MS received 20 May 2012; revised 6 December 2012; accepted ...
Ves aprel "Aprelju" ver / Lidija Tolmatshova
Tolmatshova, Lidija
2001-01-01
Kunstnike rühmituse "Aprill" - Aleksandr ja Nadezhda Popolitov, Vladislav ja Jelena Kuznetsov, Tatjana Petsheritsa, Igor Lukjanov, Sergei Kolesnikov, Aleksandr Orlov, Eduard Zentshik, Vladimir Zujev, German Jershov - näituse avamisest Sillamäel kehamaalingutega
Maja kaldapealsel / Vaapo Vaher
Vaher, Vaapo, 1945-
2002-01-01
Ilmunud ka: Vaher, Vaapo. Kokaiin Balti jaama turult: miniatuure vene kultuurist. Tallinn : Sirp, 2003, lk. 109-111. 1932. a. arhitekt Boriss Jofani projekti järgi Moskvasse Serafimovitshi t. ehitatud 11-korruselisest, 505 korteriga konstruktivistlikust hoonest, mis oli mõeldud riigi-, partei- ja sõjaväeeliidi (Nikolai Buhharin, Georgi Zhukov, Aleksei Kossõgin, Nikita Hrushtshov jt) elukohaks. Hoonet kutsutakse Juri Trifonovi romaani pealkirja järgi "Maja kaldapealsel"
Bagatellid : maailm / Nele-Eva Steinfeld, Ivo Heinloo
Steinfeld, Nele-Eva
2011-01-01
Muusikasõnumeid maailmast: Grammy nominentide seas Arvo Pärt, Eesti Riiklik Sümfooniaorkester ja Eesti Filharmoonia Kammerkoor. Louis Andriessen võitis Grawemeyeri preemia. Sibeliuse-nimelise viiuldajate konkursi võitis Nikita Borisoglebski. Kristiina Poska jõudis Donatella Flicki nimelise dirigentide konkursi finaali. Benjamin Koppel pälvis jazziauhinna Ben Webster Prize. Newporti jazzifestival jäi sponsorita. Down Beati jazzikriitikud valisid 2010. aasta parimad (nimekiri)
Смешение настроений в "Углах" / Ксения Репсон
Репсон, Ксения
2005-01-01
Pealinna kirjandusliku ühenduse "Углы" muusikaline luuleõhtu "Re-Start" Tallinna kohvikus Double Coffee. Esinevad internetilehekülje "Современная литература в Таллинне" looja P. I. Filimonov ja tema kaaskond: Sergei Trofimov, Nikita Dubrovin, Art Noir [Deniss Kuzmin], Ligija Tenina, Jevgeni Zolotorevski
Indian Academy of Sciences Conference Series | Indian Academy of ...
Home; Journals; Indian Academy of Sciences Conference Series. SERGEY P KUZNETSOV. Articles written in Indian Academy of Sciences Conference Series. Volume 1 Issue 1 December 2017 pp 117-132 Proceedings of the Conference on Perspectives in Nonlinear Dynamics - 2016. Chaos in three coupled rotators: ...
25 kaadrit sekundis / Liis Auväärt
Auväärt, Liis
2009-01-01
Nukufilmis käib töö filmiga "Lisa Limone & Maroc Orange", režissöör Mait Laas, animaatorid Triin Sarapik-Kivi, Märt Kivi, operaator Ragnar Neljandi, nukumeistrid Heigo Eeriksoo, Taivo Müürsep, Ene Mellow ja Kreeta Käeri. Dekoratsioonimeistrid Mait Erik ja Roman Kuznetsov
Koornwinder, T.H.
2007-01-01
Vadim Kuznetsov Memorial Issue on Integrable Systems and Related Topics Abstract Zhedanov's algebra AW(3) is considered with explicit structure constants such that, in the basic representation, the first generator becomes the second order q-difference operator for the Askey-Wilson polynomials. It is
Sum formula for SL2 over imaginary quadratic number fields
Lokvenec-Guleska, H.
2004-01-01
The subject of this thesis is generalization of the classical sum formula of Bruggeman and Kuznetsov to the upper half-space H3. The derivation of the preliminary sum formula involves computation of the inner product of two specially chosen Poincar´e series in two different ways: the spectral
The transmission of finite amplitude sound beam in multi-layered biological media
Liu, Xiaozhou; Li, Junlun; Yin, Chang; Gong, Xiufen; Zhang, Dong; Xue, Honghui
2007-02-01
Based on the Khokhlov Zabolotskaya Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media.
The transmission of finite amplitude sound beam in multi-layered biological media
Liu, Xiaozhou [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)]. E-mail: xzliu@nju.edu.cn; Li, Junlun [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Yin, Chang [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Gong, Xiufen [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Zhang, Dong [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Xue, Honghui [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)
2007-02-19
Based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media.
The transmission of finite amplitude sound beam in multi-layered biological media
Liu, Xiaozhou; Li, Junlun; Yin, Chang; Gong, Xiufen; Zhang, Dong; Xue, Honghui
2007-01-01
Based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media
A new theoretical basis for numerical simulations of nonlinear acoustic fields
Wójcik, Janusz
2000-07-01
Nonlinear acoustic equations can be considerably simplified. The presented model retains the accuracy of a more complex description of nonlinearity and a uniform description of near and far fields (in contrast to the KZK equation). A method has been presented for obtaining solutions of Kuznetsov's equation from the solutions of the model under consideration. Results of numerical calculations, including comparative ones, are presented.
Hea teater lastele ja noortele / Katrin Ruus
Ruus, Katrin
2006-01-01
22.-27. maini Tallinnas, Tartus, Pärnus, Narvas toimunud laste- ja noortetatrite festivalist "Draamake 2006". Nimetatud auhinnasaajad : lastelavastuse auhinna sai Vanemuise "Suur kuri hunt" (lavastaja Taago Tubin), noorsooteatri auhind määrati Vene Teatri lavastusele "Veerevad kivid ei sammaldu" (lavastaja Nikita Grinshpun), näitlejaauhinnaga pärjati Marika Vaarikut osatäitmise eest VAT Teatri lavastuses "Klammi sõda", publikupuudutuse auhinna sai ZUGA ühendatud tantsijate "ZUGA lastekas" ja sõnajõuauhind läks NO99 teatri lavastusele "Kaks päikest" (lavastaja Andres Noormets)
Vanemuise "Suur kuri hunt" valiti parimaks lastelavastuseks / Brigitta Davidjants
Davidjants, Brigitta, 1983-
2006-01-01
27. mail lõppenud laste- ja noorteteatrite festivalist "Draamake 2006". Lastelavastuse auhinna sai Vanemuise "Suur kuri hunt" (lavastaja Taago Tubin), noorsooteatri auhind määrati Vene Teatri lavastusele "Veerevad kivid ei sammaldu" (lavastaja Nikita Grinshpun), näitlejaauhinnaga pärjati Marika Vaarikut osatäitmise eest VAT Teatri lavastuses "Klammi sõda", publikupuudutuse auhinna sai ZUGA ühendatud tantsijate "ZUGA lastekas" ja sõnajõuauhind läks NO99 teatri lavastusele "Kaks päikest"( lavastaja Andres Noormets)
С. Ю. Хохлов
2013-08-01
Full Text Available The article mentions that the special attention is deserved by such persimmon varieties being included into the collection of Garden: Nikita Burgundy – the most famous of the hardiest varieties, widely used in industrial horticulture grade foreign breeding Hana Fuyu and a new, high-yielding variety of domestic breeding Souvenir of Autumn. Plant varieties included into the studying, grow in the same conditions at the collection site, which is located 200 meters from the coast at a height of 20-40 m above its level. Trees are 15 years old, planting scheme is 6x6 meters. The selected varieties belong to the group of constant tart on their quality whose fruits are edible only when fully ripe Varieties are characterized by high winter hardiness and disease resistance, which allows minimizing the chemicals using for plants treating and creates the conditions for organic food. The chemical composition fruits studying of three oriental persimmons varieties have performed high content of potassium, so it affords their using as a general tonic. The obtained results have revealed that according to the content of essential elements the leading fruit of variety Souvenir Autumn is considered to be, the less valuable are fruits of Nikita Burgundy, and Hana Fuyu fruits on this indicator are intermediate.
Ragnisco, Orlando; Zullo, Federico
2010-01-01
We construct a two-parameter family of Baecklund transformations for the trigonometric classical Gaudin magnet. The approach follows closely the one introduced by Sklyanin and Kuznetsov (1998 J. Phys. A: Math. Gen. 31 2241-51) in a number of seminal papers and takes advantage of the intimate relation between the trigonometric and the rational case. As in the paper by Hone, Kuznetsov and one of the authors (OR) (2001 J. Phys. A: Math. Gen. 34 2477-90) the Baecklund transformations are presented as explicit symplectic maps, starting from their Lax representation. The (expected) connection with the xxz Heisenberg chain is established and the rational (xxx) case is recovered in a suitable limit. It is shown how to obtain a 'physical' transformation mapping real variables into real variables. The interpolating Hamiltonian flow is derived and some numerical iterations of the map are presented.
Hello out there...is anybody listening?
DeFilippis, Rosa Anna; Tlsty, Thea D
2012-12-01
Using a murine xenograft model system, Kuznetsov and colleagues show the existence of systemic interactions between a primary tumor and the growth of distal tumors in both homotypic and heterotypic tissues. Importantly, they show that the characteristics of the primary tumor govern the histologic features of the distal tumor through distinct pathways, thus providing novel opportunities for risk assessment, prognosis, prevention, and intervention. ©2012 AACR.
Application of Exp-function method for (2 + 1)-dimensional nonlinear evolution equations
Bekir, Ahmet; Boz, Ahmet
2009-01-01
In this paper, the Exp-function method is used to construct solitary and soliton solutions of (2 + 1)-dimensional nonlinear evolution equations. (2 + 1)-dimensional breaking soliton (Calogero) equation, modified Zakharov-Kuznetsov and Konopelchenko-Dubrovsky equations are chosen to illustrate the effectiveness of the method. The method is straightforward and concise, and its applications are promising. The Exp-function method presents a wider applicability for handling nonlinear wave equations.
Jaama jões talvitunud kalad surid hapnikunälga / Külli Kriis
Kriis, Külli, 1961-
2006-01-01
Vt. ka Severnoje Poberezhje 21. apr. Illuka vallavalitsuse kommunaalnõunik Oleg Kuznetsov näeb süüd kalade suremises mitte niivõrd madalas veetasemes ja jää kauases püsimises, kuivõrd selles, et vanajõgi on mõlemast Narva jõega ühenduses olevast otsast täis settinud
Russian Cosmism, Global Crisis, Sustainable Development
Kuznetsov Oleg; Bolshakov Boris
2013-01-01
The article is based on the scientific report by O.L.Kuznetsov and B.E.Bolshakov at the General Meeting of Russian Academy of Natural Sciences (December 6, 2012). The scientific report caused a great interest, and many scientists suggested to open discussion in the press on this subject. The article reveals the natural-scientific and humanitarian mechanisms of global crisis and a transition way to sustainable development on the basis of world scientific heritage and, first of all, fundamental...
Stable solitary waves in super dense plasmas at external magnetic fields
Ghaani, Azam; Javidan, Kurosh; Sarbishaei, Mohsen
2015-07-01
Propagation of localized waves in a Fermi-Dirac distributed super dense matter at the presence of strong external magnetic fields is studied using the reductive perturbation method. We have shown that stable solitons can be created in such non-relativistic fluids in the presence of an external magnetic field. Such solitary waves are governed by the Zakharov-Kuznetsov (ZK) equation. Properties of solitonic solutions are studied in media with different values of background mass density and strength of magnetic field.
Climatic wind tunnel for wind engineering tasks
Kuznetsov, Sergeii; Pospíšil, Stanislav; Král, Radomil
2015-01-01
Roč. 112, 2-B (2015), s. 303-316 ISSN 1897-628X R&D Projects: GA ČR(CZ) GA14-12892S Keywords : climatic tunnel * wind tunnel * atmospheric boundary layer * flow resistance * wind tunnel contraction Subject RIV: JM - Building Engineering https://suw.biblos.pk.edu.pl/resources/i5/i6/i6/i7/i6/r56676/KuznetsovS_ClimaticWind.pdf
Conservation Laws and Traveling Wave Solutions of a Generalized Nonlinear ZK-BBM Equation
Khadijo Rashid Adem
2014-01-01
Full Text Available We study a generalized two-dimensional nonlinear Zakharov-Kuznetsov-Benjamin-Bona-Mahony (ZK-BBM equation, which is in fact Benjamin-Bona-Mahony equation formulated in the ZK sense. Conservation laws for this equation are constructed by using the new conservation theorem due to Ibragimov and the multiplier method. Furthermore, traveling wave solutions are obtained by employing the (G'/G-expansion method.
The Death of the Capital Ship: Is There a Place for Supercarriers in Modern Navies
2013-04-01
tons with the lone exception of the Russian carrier the Admiral Kuznetsov which displaces 67,500 tons.3 This allows the supercarriers to load more...from land bases more easily and cheaply than from a carrier. However, unlike other nations, as the world’s lone superpower the United States has...first reason and foremost reason why only one nation (with the largest defense budget on the planet ) has a fleet of supercarriers is the cost to
2012-01-01
Noorte ettevõtluskonkursi Ajujaht finalistidest: Richard Murutar (Dolphin), Andrus Purde (Achoo), Kalev Külaase, Ülane Vilumets, Rait Kapp (Kohalik Giid), Mart Raus, Vahur Mäe (Grillcube), Dmitri Kuznetsov, Anna Agronova, Julia Abolina, Anatoly Loginov (Healthiest.mobi), Karin Juhe, Karin Aruots (Korsid), Raino Sinisalu, Märt Pikkani, Arkadi Tammik, Varje Papp (Raybike), Egle Loit, Kair Käsper (Pille toidukott)
Geological Structure of the Basement of Western and Eastern Parts of the West-Siberian Plain
Ivanov, Kirill S.; Erokhin, Yuriy V.; Ponomarev, Vladimir S.; Pogromskaya, Olga E.; Berzin, Stepan V.
2016-01-01
The U-Pb dating (SHRIMP-II on zircon) was obtained for the first time from the basement of the West Siberian Plain in the Western half of the region. It is established that a large part of the protolith of the metamorphic depth in the Shaim-Kuznetsov meganticlinorium contained sedimentary late- and middle-Devonian rocks (395-358 million years).…
Acoustic Microscopy and Nonlinear Effects in Pressurized Superfluid Helium
1993-08-31
Fresnel or parabolic approxi nations [16,17]. With the development of the Khokhlov-Zabolotskaya-Kuznetsov ( KZK ) paratolic equation [18,191, which...sound waves in a thermoviscous liquid by means of the KZK equation. (2) Hart and Hamilton [261 employed a con- vergent coordinate system that...improves the efficiency of the numerical solution of the KZK equa- tion for focused beams. (3) Lucas and Muir [27] developed an equivalency relationship
Numerical methods for axisymmetric and 3D nonlinear beams
Pinton, Gianmarco F.; Trahey, Gregg E.
2005-04-01
Time domain algorithms that solve the Khokhlov--Zabolotzskaya--Kuznetsov (KZK) equation are described and implemented. This equation represents the propagation of finite amplitude sound beams in a homogenous thermoviscous fluid for axisymmetric and fully three dimensional geometries. In the numerical solution each of the terms is considered separately and the numerical methods are compared with known solutions. First and second order operator splitting are used to combine the separate terms in the KZK equation and their convergence is examined.
1987-07-01
fields (see also Chapter 4 of Ref. 22). Like our investigation, theirs is based on the Khokhlov-Zabolotskaya-Kuznetsov ( KZK ) equa- tion [23,24...25,26], also based on the KZK e(iualiou, is limited to weakly nonlinear systems. However, the practical case of a focused circular source with gain of...iment. The demonstrated abihty of the KZK equation to accurately model focused sound fields from reahstic sources [i.e., having abrupt edges and
Geometric Methods in the Algebraic Theory of Quadratic Forms : Summer School
2004-01-01
The geometric approach to the algebraic theory of quadratic forms is the study of projective quadrics over arbitrary fields. Function fields of quadrics have been central to the proofs of fundamental results since the renewal of the theory by Pfister in the 1960's. Recently, more refined geometric tools have been brought to bear on this topic, such as Chow groups and motives, and have produced remarkable advances on a number of outstanding problems. Several aspects of these new methods are addressed in this volume, which includes - an introduction to motives of quadrics by Alexander Vishik, with various applications, notably to the splitting patterns of quadratic forms under base field extensions; - papers by Oleg Izhboldin and Nikita Karpenko on Chow groups of quadrics and their stable birational equivalence, with application to the construction of fields which carry anisotropic quadratic forms of dimension 9, but none of higher dimension; - a contribution in French by Bruno Kahn which lays out a general fra...
Distribution of Erysiphe platani (Erysiphales in Ukraine
Vasyl P. Heluta
2013-12-01
Full Text Available Information is provided on Erysiphe platani, a newly invasive fungus in Ukraine. The anamorph of this North American powdery mildew was first recorded in Ukraine in 1986 on Platanus orientalis in the Nikita Botanical Garden (Crimea. Later, it was found in other localities of the Crimean peninsula, and in Odessa and Odessa region on three species of plane, namely P. × hispanica, P. occidentalis and P. orientalis. Spread of the fungus was epiphytotic. This mildew significantly reduces the ornamental value of plane trees, which are often planted in public open spaces within urban areas of southern Ukraine. Recently, E. platani has formed the teleomorph in this region. Morphologically, the Ukrainian material is slightly different from the species description, viz. appendages are longer (up to 3 times the chasmothecial diam., often with less compact apices.
How Nuclear South Asia is Like Cold War Europe:
Cohen, Michael David
2013-01-01
Conventional wisdom states that the stability-instability paradox does not explain the effect of nuclear proliferation on the conflict propensity of South Asia and that nuclear weapons have had a different and more dangerous impact in South Asia than Cold War Europe. I argue that the paradox...... Europe and South Asia. Pakistani President Pervez Musharraf may have adopted more moderate foreign policy towards India after experiencing fear of imminent nuclear war during the ten month mobilised crisis in 2002 as Nikita Khrushchev did forty years earlier. I argue that the stability-instability...... explains nuclear South Asia, that the similarities between nuclear South Asia and Cold War Europe are strong, and that conventional instability does not cause revisionist challenges in the long run. I develop and probe a psychological causal mechanism that explains the impact of nuclear weapons on Cold War...
Fasoula, S; Zisi, Ch; Gika, H; Pappa-Louisi, A; Nikitas, P
2015-05-22
A package of Excel VBA macros have been developed for modeling multilinear gradient retention data obtained in single or double gradient elution mode by changing organic modifier(s) content and/or eluent pH. For this purpose, ten chromatographic models were used and four methods were adopted for their application. The methods were based on (a) the analytical expression of the retention time, provided that this expression is available, (b) the retention times estimated using the Nikitas-Pappa approach, (c) the stepwise approximation, and (d) a simple numerical approximation involving the trapezoid rule for integration of the fundamental equation for gradient elution. For all these methods, Excel VBA macros have been written and implemented using two different platforms; the fitting and the optimization platform. The fitting platform calculates not only the adjustable parameters of the chromatographic models, but also the significance of these parameters and furthermore predicts the analyte elution times. The optimization platform determines the gradient conditions that lead to the optimum separation of a mixture of analytes by using the Solver evolutionary mode, provided that proper constraints are set in order to obtain the optimum gradient profile in the minimum gradient time. The performance of the two platforms was tested using experimental and artificial data. It was found that using the proposed spreadsheets, fitting, prediction, and optimization can be performed easily and effectively under all conditions. Overall, the best performance is exhibited by the analytical and Nikitas-Pappa's methods, although the former cannot be used under all circumstances. Copyright © 2015 Elsevier B.V. All rights reserved.
On function classes related pertaining to strong approximation of double Fourier series
Baituyakova, Zhuldyz
2015-09-01
The investigation of embedding of function classes began a long time ago. After Alexits [1], Leindler [2], and Gogoladze[3] investigated estimates of strong approximation by Fourier series in 1965, G. Freud[4] raised the corresponding saturation problem in 1969. The list of the authors dealing with embedding problems partly is also very long. It suffices to mention some names: V. G. Krotov, W. Lenski, S. M. Mazhar, J. Nemeth, E. M. Nikisin, K. I. Oskolkov, G. Sunouchi, J. Szabados, R. Taberski and V. Totik. Study on this topic has since been carried on over a decade, but it seems that most of the results obtained are limited to the case of one dimension. In this paper, embedding results are considered which arise in the strong approximation by double Fourier series. We prove theorem on the interrelation between the classes Wr1,r2HS,M ω and H(λ, p, r1, r2, ω(δ1, δ2)), in the one-dimensional case proved by L. Leindler.
Bowman, H. R.; Thompson, S. G.; Watson, R. L.; Kapoor, S. S.; Rasmussen, J. O. [Lawrence Radiation Laboratory, University of California, Berkeley, CA (United States)
1965-07-15
detectores de semiconductores, de elevado poder de resolucion. Las masas de los fragmentos se dedujeron de sus respectivas energias y las cargas nucleares se determinaron midiendo las energias de los rayos X-K vinculadas a las distintas masas. La magnitud y el signo del desplazamiento de Doppler permitio asignar les lineas espectrales de ios rayos gamma, a cada uno de los componentes de cada par de fragmentos. El desplazamiento de Doppler permite tambien medir independientemente la velocidad de los fragmentos y, por consiguiente, la masa de estos despues de la emision de un neutron. Los resultados de las mediciones realizadas sobre los rayos X concuerdan con la hipotesis de que la mayoria de los rayos X inmediatos emitidos durante la fision espontanea del {sup 252}Cf, son resultado de la conversion interna en los fragmentos de la fision primaria,, durante la desexcitacion de estados colectivos de baja energia. Ademas de los resultados concretos examinados en U memoiia, la consecuencia mas importante de los experimentos descritos es la demostracion de que es posible estudiar por separado las propiedades de cada fragmento de fision, identificado por sus radiaciones caracteristicas (en lugar de estudiar las propiedades de un fragmento de fision medio, con masa y carga tambien medias). Se estudian actualmente las consecuencias de este adelanto logrado en la tecnica de estudio de los fragmentos de fision. (author) [Russian] Nabljudalis' horosho opredelennye mgnovennye gamma-kvanty, mgnovennye konversionnye jelektrony i rentgenovskoe K-izluchenie v sovpadenii s dvizhushhimisja oskolkami delenija kalifornija-252. V neskol'kih sluchajah byli ustanovleny massy i zarjady jader, ispuskajushhih gamma-kvanty i konversionnye jelektrony. Jenergii gamma-kvantov, mgnovennyh jelektronov i mgnovennyh rentgenovskih luchej, a takzhe jenergii dvuh oskolkov delenija byli izmereny s pomoshh'ju tverdogo schetchika s vysokoj razreshajushhej sposobnost'ju. Massy oskolkov byli vyvedeny na osnove ih
Ghalambor Dezfuly, S.; Dorranian, D.
2012-01-01
In this manuscript, the effect of dust electrical charge, nonthermal ions, and external magnetic field on the shape and propagation of solitons in dusty plasma with two nonthermal ions is studied theoretically. Using the reductive perturbation theory, the Zakharov-Kuznetsov equation for propagation of dust acoustic waves is extracted. Results show that external magnetic field does not affect the amplitude of solitary wave but width of solitons are effectively depend on the magnitude of external magnetic field. With increasing the charge of dust particles the amplitude of solution will increase while their width will decrease. Increasing the nonthermal ions lead to opposite effect.
Doktoriväitekiri komi keele kohakäänete ruumisemantikast / Galina Nekrassova
Nekrassova, Galina
2013-01-01
27. dets. 2012. a. kaitses Nikolay Kuznetsov Tartu ülikooli eesti ja üldkeeleteaduse instituudis doktoriväitekirja "Пространственная семантика местных падежей коми языка (когнитивный анализ)" ("Komi keele kohakäänete ruumisemantika (kognitiivne analüüs)")
The Dynamical Behaviors for a Class of Immunogenic Tumor Model with Delay
Ping Bi
2017-01-01
Full Text Available This paper aims at studying the model proposed by Kuznetsov and Taylor in 1994. Inspired by Mayer et al., time delay is introduced in the general model. The dynamic behaviors of this model are studied, which include the existence and stability of the equilibria and Hopf bifurcation of the model with discrete delays. The properties of the bifurcated periodic solutions are studied by using the normal form on the center manifold. Numerical examples and simulations are given to illustrate the bifurcation analysis and the obtained results.
TÜ ja TPÜ uusi magistreid 2002 / Tiia Margus, Hille Roots, Krista Kerge
Margus, Tiia
2003-01-01
TÜ eesti ja soome-ugri keeleteaduse osakonnas kaitsesid 2002.a. magistritööd N. Gordejeva, T. Leemets, S. Mäearu, M. Raadik, A. Tavast, K. Kikas, S. Iva, T. Iva, N. Kuznetsov, K. Strandson, L. Talejeva, M. Allik, V. Ernštreits, K. Kuldnokk, K. Praakli, E. Laanes, A. Pilv, K. Talviste, L. Hion, P. Noorhani, R. Hindrikus, J. Oras, L. Jääts. TPÜ eesti keele ja soome-ugri keelte magistrikraadi kaitsmisnõukogu ees kaitsesid magistritööd M. Pesti, K. Aava, J. Kallas, A. Lange, I. Kivirähk
Bidispersive-inclined convection
Mulone, Giuseppe; Straughan, Brian
2016-01-01
A model is presented for thermal convection in an inclined layer of porous material when the medium has a bidispersive structure. Thus, there are the usual macropores which are full of a fluid, but there are also a system of micropores full of the same fluid. The model we employ is a modification of the one proposed by Nield & Kuznetsov (2006 Int. J. Heat Mass Transf. 49, 3068–3074. (doi:10.1016/j.ijheatmasstransfer.2006.02.008)), although we consider a single temperature field only. PMID:27616934
Dust ion-acoustic shock waves in magnetized pair-ion plasma with kappa distributed electrons
Kaur, B.; Singh, M.; Saini, N. S.
2018-01-01
We have performed a theoretical and numerical analysis of the three dimensional dynamics of nonlinear dust ion-acoustic shock waves (DIASWs) in a magnetized plasma, consisting of positive and negative ion fluids, kappa distributed electrons, immobile dust particulates along with positive and negative ion kinematic viscosity. By employing the reductive perturbation technique, we have derived the nonlinear Zakharov-Kuznetsov-Burgers (ZKB) equation, in which the nonlinear forces are balanced by dissipative forces (associated with kinematic viscosity). It is observed that the characteristics of DIASWs are significantly affected by superthermality of electrons, magnetic field strength, direction cosines, dust concentration, positive to negative ions mass ratio and viscosity of positive and negative ions.
Khaustov, Alexander A
2014-05-06
Three new species of the genus Stigmaeus Koch, 1836 (Acari: Stigmaeidae) are described from various habitats in Crimea: Stigmaeus kuznetsovi sp. nov. from nests of Microtus socialis (Rodentia: Cricetidae); S. mitrofanovi sp. nov. from galleries of Pityogenes bistridentatus (Coleoptera: Curculionidae) under the bark of Pinus pallasiana, and S. silvestris sp. nov. from rotten log of Pinus pallasiana. Stigmaeus corticeus Kuznetsov and Wainstein, 1977 and S. maraghehiensis Bagheri and Ueckermann, 2012 are recorded for the first time in Crimea. A key to species of the genus Stigmaeus of Crimea is provided.
Ata-ur-Rahman,; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); Masood, W. [National Centre for Physics, QAU Campus, Shahdrah Valley Road, Islamabad 44000 (Pakistan); COMSATS, Institute of Information Technology, Park Road, Chak Shahzad, Islamabad 44000 (Pakistan); Eliasson, B. [Physics Department, University of Strathclyde, Glasgow G4 0NG, Scotland (United Kingdom)
2013-09-15
In this paper, small but finite amplitude electrostatic solitary waves in a relativistic degenerate magnetoplasma, consisting of relativistically degenerate electrons and non-degenerate cold ions, are investigated. The Zakharov-Kuznetsov equation is derived employing the reductive perturbation technique and its solitary wave solution is analyzed. It is shown that only compressive electrostatic solitary structures can propagate in such a degenerate plasma system. The effects of plasma number density, ion cyclotron frequency, and direction cosines on the profiles of ion acoustic solitary waves are investigated and discussed at length. The relevance of the present investigation vis-a-vis pulsating white dwarfs is also pointed out.
Plant maintenance and advanced reactors, 2006
Agnihotri, Newal (ed.)
2006-09-15
The focus of the September-October issue is on plant maintenance and advanced reactors. Major articles/reports in this issue include: Advanced plants to meet rising expectations, by John Cleveland, International Atomic Energy Agency, Vienna; A flexible and economic small reactor, by Mario D. Carelli and Bojan Petrovic, Westinghouse Electric Company; A simple and passively safe reactor, by Yury N. Kuznetsov, Research and Development Institute of Power Engineering (NIKIET), Russia; Gas-cooled reactors, by Jeffrey S. Merrifield, U.S. Nuclear Regulatory Commission; ISI project managment in the PRC, by Chen Chanbing, RINPO, China; and, Fort Calhoun refurbishment, by Sudesh Cambhir, Omaha Public Power District.
Yoshioka, Masahiro; Sato, Sojun; Kikuchi, Tsuneo; Matsuda, Yoichi
2006-05-01
In this study, the influence of ultrasonic nonlinear propagation on hydrophone calibration by the two-transducer reciprocity method is investigated quantitatively using the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. It is proposed that the correction for the diffraction and attenuation of ultrasonic waves used in two-transducer reciprocity calibration can be derived using the KZK equation to remove the influence of nonlinear propagation. The validity of the correction is confirmed by comparing the sensitivities calibrated by the two-transducer reciprocity method and laser interferometry.
Higher-order harmonics of general limited diffraction Bessel beams
Ding De-Sheng; Huang Jin-Huang
2016-01-01
In this paper, we extensively study the higher-order harmonic generation of the general limited diffraction m -th-order Bessel beam. The analysis is based on successive approximations of the Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation. Asymptotic expansions are presented for higher-order harmonic Bessel beams in near and far fields. The validity of asymptotic approximation is also analyzed. The higher-order harmonic of the Bessel beam with the lowest zero-order is taken as a special example. (special topic)
Higher-order harmonics of general limited diffraction Bessel beams
Ding, De-Sheng; Huang, Jin-Huang
2016-12-01
In this paper, we extensively study the higher-order harmonic generation of the general limited diffraction m-th-order Bessel beam. The analysis is based on successive approximations of the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. Asymptotic expansions are presented for higher-order harmonic Bessel beams in near and far fields. The validity of asymptotic approximation is also analyzed. The higher-order harmonic of the Bessel beam with the lowest zero-order is taken as a special example. Project supported by the National Natural Science Foundation of China (Grant Nos. 11074038 and 11374051).
The shock formation distance in a bounded sound beam of finite amplitude.
Tao, Chao; Ma, Jian; Zhu, Zhemin; Du, Gonghuan; Ping, Zihong
2003-07-01
This paper investigates the shock formation distance in a bounded sound beam of finite amplitude by solving the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation using frequency-domain numerical method. Simulation results reveal that, besides the nonlinearity and absorption, the diffraction is another important factor that affects the shock formation of a bounded sound beam. More detailed discussions of the shock formation in a bounded sound beam, such as the waveform of sound pressure and the spatial distribution of shock formation, are also presented and compared for different parameters.
Yu, Li-Li; Shou, Wen-De; Hui, Chun
2012-02-01
A theoretical model of focused acoustic field for a multi-annular phased array on concave spherical surface is proposed. In this model, the source boundary conditions of the spheroidal beam equation (SBE) for multi-annular phased elements are studied. Acoustic field calculated by the dynamic focusing model of SBE is compared with numerical results of the O'Neil and Khokhlov—Zabolotskaya—Kuznetsov (KZK) model, respectively. Axial dynamic focusing and the harmonic effects are presented. The results demonstrate that the dynamic focusing model of SBE is good valid for a concave multi-annular phased array with a large aperture angle in the linear or nonlinear field.
A User-Friendly Software Package for HIFU Simulation
Soneson, Joshua E.
2009-04-01
A freely-distributed, MATLAB (The Mathworks, Inc., Natick, MA)-based software package for simulating axisymmetric high-intensity focused ultrasound (HIFU) beams and their heating effects is discussed. The package (HIFU_Simulator) consists of a propagation module which solves the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation and a heating module which solves Pennes' bioheat transfer (BHT) equation. The pressure, intensity, heating rate, temperature, and thermal dose fields are computed, plotted, the output is released to the MATLAB workspace for further user analysis or postprocessing.
Deryabin, M. S.; Kasyanov, D. A.; Kurin, V. V.; Garasyov, M. A.
2016-05-01
We show that a significant energy redistribution occurs in the spectrum of reflected nonlinear waves, when an intense acoustic beam is reflected from an acoustically soft boundary, which manifests itself at short wave distances from a reflecting boundary. This effect leads to the appearance of extrema in the distributions of the amplitude and intensity of the field of the reflected acoustic beam near the reflecting boundary. The results of physical experiments are confirmed by numerical modeling of the process of transformation of nonlinear waves reflected from an acoustically soft boundary. Numerical modeling was performed by means of the Khokhlov—Zabolotskaya—Kuznetsov (KZK) equation.
Focusing of high power ultrasound beams and limiting values of shock wave parameters
Bessonova, O. V.; Khokhlova, V. A.; Bailey, M. R.; Canney, M. S.; Crum, L. A.
2009-10-01
In this work, the influence of nonlinear and diffraction effects on amplification factors of focused ultrasound systems is investigated. The limiting values of acoustic field parameters obtained by focusing of high power ultrasound are studied. The Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation was used for the numerical modeling. Solutions for the nonlinear acoustic field were obtained at output levels corresponding to both pre- and post-shock formation conditions in the focal area of the beam in a weakly dissipative medium. Numerical solutions were compared with experimental data as well as with known analytic predictions.
Club d'orientation
2013-01-01
De jour comme de nuit Les amateurs de course d’orientation ont pu s’en donner à cœur joie ce week-end puisqu’ils avaient la possibilité de courir sur deux épreuves en moins de 24 heures. En effet, le club du CERN organisait une course de nuit aux Evaux et la 7e étape de la coupe genevoise se tenait samedi après-midi dans les bois du Grand Jorat à Savigny. Les vainqueurs pour chaque course sont : Technique long CO de nuit: Julien Charlemagne, SOS Sallanches CO samedi: Philipp Khlebnikov, ANCO Technique moyen CO de nuit: Céline Zosso, CO CERN CO samedi: Pavel Khlebnikov, ANCO Technique court CO de nuit: Colas Ginztburger, SOS Sallanches CO samedi: Victor Kuznetsov, COLJ Lausannne Facile moyen CO de nuit: Gaëtan Rickenbacher, CO CERN CO samedi: Tamas Szoke Facile court CO de nuit:Oriane Rickenbacher, CO CERN CO samedi: Katya Kuznetsov...
Xin Baogui; Ma Junhai; Gao Qin
2009-01-01
We present a nonlinear discrete dynamical model of investment competition with imperfect information for N heterogeneous oligopolists in a security market. In this paper, our focus is on a given three-dimensional model which exhibits highly rich dynamical behaviors. Based on Wen's Hopf bifurcation criterion [Wen GL. Criterion to identify Hopf bifurcations in maps of arbitrary dimension. Phys Rev E 2005;72:026201-3; Wen GL, Xu DL, Han X. On creation of Hopf bifurcations in discrete-time nonlinear systems. Chaos 2002;12(2):350-5] and Kuznetsov's normal form theory [Kuznetsov YA. Elements of applied bifurcation theory. New York: Springer-Verlag; 1998. p. 125-37], we study the model's stability, criterion and direction of Neimark-Sacker bifurcation. Moreover, we numerically simulate a complexity evolution route: fixed point, closed invariant curve, double closed invariant curves, fourfold closed invariant curves, strange attractor, period-3 closed invariant curve, period-3 2-tours, period-4 closed invariant curve, period-4 2-tours.
The Danube - the Southern Border of Moldova. Historical Aspects
Ruslan Șevcenco
2014-08-01
Full Text Available For centuries the Danube was the southern border of Moldova. Moldova had the following ports: Chile, Izmail, Reni, Galati and others. This has contributed significantly to the economic development. Turkish authorities, becoming aware of the Danube immense importance at the trade, economic, and military-political level, partly conquered the Danube bay, which belonged to Moldova. In order to reduce the influence of Moldova, the Ottoman Empire created its own boundaries on this territory. Although divided into two (the east side was occupied by the Russian army, Moldova regained access on Danube at its previous borders, starting with the liquidation of the Turks domination. But in 1940 under the influence of Nikita Khrushchev, who had the position of first secretary of the Central Committee of the Communist Party (Bolshevik of Ukraine, the counties adjacent to the Danube - the territory between the Prut and Nistru - were transferred to Ukraine and its membership remained until the present days. The current authorities had managed to keep only a small segment of the Danube bay. In this article we will elucidate how for centuries the Moldovan authorities have struggled to maintain a part of the Danube's bay.
The Beautiful and Dangerous: A New Depiction of Heroines in North American Television Drama Series
Irena Sever Globan
2016-06-01
Full Text Available Television drama series are nowadays one of the most common television formats in the entertainment program genre. On the one hand, heroes and heroines of these series mirror social and cultural realities and changes, whereas on the other, they offer imitation models and shape ideas about, among other things, what being male and female means. While in the first three decades of their existence television series predominantly showed stereotypical male-female relationships through active heroes and passive housewives, in the last two decades we have witnessed changes which question the stereotypical depiction of gender roles. Television started presenting new main heroines that are equally courageous, independent, intelligent and violent as their male partners although they continue to perpetuate the stereotypical depiction in terms of physical attractiveness and sex appeal. This primarily refers to the protagonists of North American series such as Buffy, Nikita, Xena, Alias, Revenge, Rogue, etc. This paper discusses the characteristics of these new heroines in the leading roles and their potential to redefine the female character.
Functional features of travel magazines: retrospective view
Gromova Lyudmila Petrovna
2015-09-01
Full Text Available The article considers the features of the functional purpose of travel magazines (travelogue, their genesis, evolution, traits, depending on the socio-political context and, accordingly, requests from the readership. The progenitor of the travel magazines in Russia was journey literature that took root in the genre of travel notes. The forerunner of today’s travelogues can be considered «Nikita Akinfievich Demidov’s travel magazine» (1786, presenting daily travel notes, mostly laconic, sometimes deployed to fascinating travel notes Magazines at different times performed cultural and educational, didactic, aesthetic and ideological functions, immersing the reader in the living conditions of the countries and continents, showing the diversity of the world. Today, traveling is seen as a multifaceted activity that is due to the result of freedom of movement, numerous hiking trails, access to information in the network space takes new character. Accordingly, the media market is a process of qualitative and quantitative changes. There is a growing number of distribution channels, many of which are convergent evolution. The transformation of the old forms is determined by market demand. These processes are inevitably reflected in the dominance of certain functions of the travelogue. However, their essential purpose remains the same: to inform, educate and entertain.
David K. GOODIN
2018-01-01
Full Text Available The Orthodox theological worldview often finds itself confronted by the unspoken nihilism of empiricism, with little common ground for dialogue. This article establishes that common ground for discursive exchange through exploring the apophatic aspects of Kantian transcendental theology, which in turn can become a bridge to the Orthodox negative theology. Kant drew continental thought along certain foundational lines with his critique of pure reason and transcendental idealism; it was his way to locate empirical science with respect to the perceptual foundations of thought, which are properly understood philosophically. In this project, Kant would seek to secure the Christian faith in the transcendental—i.e., that which underlies all empirical experience. Even so, certain openings to traditional religious mysticism are also to be found in his project, particularly with respect to transcendental theology. This article explores these Kantian foundations for an apophatic transcendental theology in relation to the hesychastic writings of Gregory of Sinai, Gregory Palamas, and Nikitas Stithatos. This in turn becomes a new inroad for dialogue with empirical science.
Rosén, Liza A H; Östman, Elin M; Shewry, Peter R; Ward, Jane L; Andersson, Annika A M; Piironen, Vieno; Lampi, Anna-Maija; Rakszegi, Marianne; Bedö, Zoltan; Björck, Inger M E
2011-11-23
Rye products typically induce low insulin responses and appear to facilitate glucose regulation. The objective of this study was to investigate differences in postprandial glucose, insulin, and satiety responses between breads made from five rye varieties. Breads made from whole grain rye (Amilo, Rekrut, Dankowski Zlote, Nikita, and Haute Loire Pop) or a white wheat bread (WWB) were tested in a randomized cross-over design in 14 healthy subjects (50 g available starch). Metabolic responses were also related to the composition of dietary fiber and bioactive compounds in the breads and to the rate of in vitro starch hydrolysis. The Amilo and Rekrut rye breads induced significantly lower insulin indices (II) than WWB. Low early postprandial glucose and insulin responses (tAUC 0-60 min) were related to higher amounts of caffeic, ferulic, sinapic, and vanillic acids in the rye breads, indicating that the phenolic acids in rye may influence glycemic regulation. All rye breads induced significantly higher subjective feelings of fullness compared to WWB. A low II was related to a higher feeling of fullness and a lower desire to eat in the late postprandial phase (180 min). The data indicate that some rye varieties may be more insulin-saving than others, possibly due to differences in dietary fiber, rate of starch hydrolysis, and bioactive components such as phenolic acids.
Singh, S. V., E-mail: satyavir@iigs.iigm.res.in; Lakhina, G. S., E-mail: lakhina@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); University of the Western Cape, Belville (South Africa); Devanandhan, S., E-mail: devanandhan@gmail.com [Indian Institute of Geomagnetism, New Panvel (W), Navi Mumbai (India); Bharuthram, R., E-mail: rbharuthram@uwc.ac.za [University of the Western Cape, Belville (South Africa)
2016-08-15
A theoretical investigation is carried out to study the obliquely propagating electron acoustic solitary waves having nonthermal hot electrons, cold and beam electrons, and ions in a magnetized plasma. We have employed reductive perturbation theory to derive the Korteweg-de-Vries-Zakharov-Kuznetsov (KdV-ZK) equation describing the nonlinear evolution of these waves. The two-dimensional plane wave solution of KdV-ZK equation is analyzed to study the effects of nonthermal and beam electrons on the characteristics of the solitons. Theoretical results predict negative potential solitary structures. We emphasize that the inclusion of finite temperature effects reduces the soliton amplitudes and the width of the solitons increases by an increase in the obliquity of the wave propagation. The numerical analysis is presented for the parameters corresponding to the observations of “burst a” event by Viking satellite on the auroral field lines.
Hyperbolic Chaos A Physicist’s View
Kuznetsov, Sergey P
2012-01-01
"Hyperbolic Chaos: A Physicist’s View” presents recent progress on uniformly hyperbolic attractors in dynamical systems from a physical rather than mathematical perspective (e.g. the Plykin attractor, the Smale – Williams solenoid). The structurally stable attractors manifest strong stochastic properties, but are insensitive to variation of functions and parameters in the dynamical systems. Based on these characteristics of hyperbolic chaos, this monograph shows how to find hyperbolic chaotic attractors in physical systems and how to design a physical systems that possess hyperbolic chaos. This book is designed as a reference work for university professors and researchers in the fields of physics, mechanics, and engineering. Dr. Sergey P. Kuznetsov is a professor at the Department of Nonlinear Processes, Saratov State University, Russia.
Rafat, A., E-mail: rafat.plasma@gmail.com; Rahman, M. M.; Alam, M. S.; Mamun, A. A. [Jahangirnagar University, Department of Physics (Bangladesh)
2016-08-15
Obliquely propagating electron-acoustic solitary waves (EASWs) in a magnetized electron−positron−ion plasma (containing nonextensive hot electrons and positrons, inertial cold electrons, and immobile positive ions) are precisely investigated by deriving the Zakharov–Kuznetsov equation. It is found that the basic features (viz. polarity, amplitude, width, phase speed, etc.) of the EASWs are significantly modified by the effects of the external magnetic field, obliqueness of the system, nonextensivity of hot positrons and electrons, ratio of the hot electron temperature to the hot positron temperature, and ratio of the cold electron number density to the hot positron number density. The findings of our results can be employed in understanding the localized electrostatic structures and the characteristics of EASWs in various astrophysical plasmas.
Tumor evasion from immune control: Strategies of a MISS to become a MASS
D' Onofrio, Alberto [Department of Epidemiology and Biostatistics, European Institute of Oncology, Via Ripamonti 435, I-20141 Milan (Italy)]. E-mail: alberto.d' onofrio@ieo.it
2007-01-15
We biologically describe the phenomenon of the evasion of tumors from immune surveillance where tumor cells, initially constrained to exist in a microscopic steady state (MISS) elaborate strategies to evade from the immune control and to reach a macroscopic steady state (MASS). We, then, describe 'evasion' as a long term loss of equilibrium in a framework of prey-predator-like models with adiabatic varying parameters, whose changes reflect the evolutionary adaptation of the tumor in a 'hostile' environment by means of the elaboration of new strategies of survival. Similarities and differences between the present work and the interesting seminal paper [Kuznetsov VA, Knott GD. Modeling tumor regrowth and immunotherapy. Math Comput Model 2001;33:1275-87] are discussed. We also propose and study a model of clonal resistance to the immune control with slowly varying adaptive mutation parameter.
Tumor evasion from immune control: Strategies of a MISS to become a MASS
D'Onofrio, Alberto
2007-01-01
We biologically describe the phenomenon of the evasion of tumors from immune surveillance where tumor cells, initially constrained to exist in a microscopic steady state (MISS) elaborate strategies to evade from the immune control and to reach a macroscopic steady state (MASS). We, then, describe 'evasion' as a long term loss of equilibrium in a framework of prey-predator-like models with adiabatic varying parameters, whose changes reflect the evolutionary adaptation of the tumor in a 'hostile' environment by means of the elaboration of new strategies of survival. Similarities and differences between the present work and the interesting seminal paper [Kuznetsov VA, Knott GD. Modeling tumor regrowth and immunotherapy. Math Comput Model 2001;33:1275-87] are discussed. We also propose and study a model of clonal resistance to the immune control with slowly varying adaptive mutation parameter
El-Taibany, W. F.; El-Siragy, N. M.; Behery, E. E.; Elbendary, A. A.; Taha, R. M.
2018-05-01
The propagation characteristics of dust acoustic waves (DAWs) in a dusty plasma consisting of variable size dust grains, hybrid Cairns-Tsallis-distributed electrons, and nonthermal ions are studied. The charging of the dust grains is described by the orbital-motion-limited theory and the size of the dust grains obeys the power law dust size distribution. To describe the nonlinear propagation of the DAWs, a Zakharov-Kuznetsov equation is derived using a reductive perturbation method. It is found that the nonthermal and nonextensive parameters influence the main properties of DAWs. Moreover, our results reveal that the rarefactive waves can propagate mainly in the proposed plasma model while compressive waves can be detected for a very small range of the distribution parameters of plasma species, and the DAWs are faster and wider for smaller size dust grains. Applications of the present results to dusty plasma observations are briefly discussed.
Drift effects on electromagnetic geodesic acoustic modes
Sgalla, R. J. F., E-mail: reneesgalla@gmail.com [Institute of Physics, University of São Paulo, São Paulo 05508-900 (Brazil)
2015-02-15
A two fluid model with parallel viscosity is employed to derive the dispersion relation for electromagnetic geodesic acoustic modes (GAMs) in the presence of drift (diamagnetic) effects. Concerning the influence of the electron dynamics on the high frequency GAM, it is shown that the frequency of the electromagnetic GAM is independent of the equilibrium parallel current but, in contrast with purely electrostatic GAMs, significantly depends on the electron temperature gradient. The electromagnetic GAM may explain the discrepancy between the f ∼ 40 kHz oscillation observed in tokamak TCABR [Yu. K. Kuznetsov et al., Nucl. Fusion 52, 063044 (2012)] and the former prediction for the electrostatic GAM frequency. The radial wave length associated with this oscillation, estimated presently from this analytical model, is λ{sub r} ∼ 25 cm, i.e., an order of magnitude higher than the usual value for zonal flows (ZFs)
Particular solutions to multidimensional PDEs with KdV-type nonlinearity
Zenchuk, A.I.
2014-01-01
We consider a class of particular solutions to the (2+1)-dimensional nonlinear partial differential equation (PDE) u t +∂ x 2 n u x 1 −u x 1 u=0 (here n is any integer) reducing it to the ordinary differential equation (ODE). In a simplest case, n=1, the ODE is solvable in terms of elementary functions. Next choice, n=2, yields the cnoidal waves for the special case of Zakharov–Kuznetsov equation. The proposed method is based on the deformation of the characteristic of the equation u t −uu x 1 =0 and might also be useful in study of the higher-dimensional PDEs with arbitrary linear part and KdV-type nonlinearity (i.e. the nonlinear term is u x 1 u).
Mamun, A.A.; Russel, S.M.; Mendoza-Briceno, C.A.; Alam, M.N.; Datta, T.K.; Das, A.K.
1999-05-01
A rigorous theoretical investigation has been made of multi-dimensional instability of obliquely propagating electrostatic solitary structures in a hot magnetized nonthermal dusty plasma which consists of a negatively charged hot dust fluid, Boltzmann distributed electrons, and nonthermally distributed ions. The Zakharov-Kuznetsov equation for the electrostatic solitary structures that exist in such a dusty plasma system is derived by the reductive perturbation method. The multi-dimensional instability of these solitary waves is also studied by the small-k (long wavelength plane wave) perturbation expansion method. The nature of these solitary structures, the instability criterion, and their growth rate depending on dust-temperature, external magnetic field, and obliqueness are discussed. The implications of these results to some space and astrophysical dusty plasma situations are briefly mentioned. (author)
AID/APOBEC cytosine deaminase induces genome-wide kataegis
Lada Artem G
2012-12-01
Full Text Available Abstract Clusters of localized hypermutation in human breast cancer genomes, named “kataegis” (from the Greek for thunderstorm, are hypothesized to result from multiple cytosine deaminations catalyzed by AID/APOBEC proteins. However, a direct link between APOBECs and kataegis is still lacking. We have sequenced the genomes of yeast mutants induced in diploids by expression of the gene for PmCDA1, a hypermutagenic deaminase from sea lamprey. Analysis of the distribution of 5,138 induced mutations revealed localized clusters very similar to those found in tumors. Our data provide evidence that unleashed cytosine deaminase activity is an evolutionary conserved, prominent source of genome-wide kataegis events. Reviewers This article was reviewed by: Professor Sandor Pongor, Professor Shamil R. Sunyaev, and Dr Vladimir Kuznetsov.
Bibliography of Soviet Laser Developments. Number 43, September-October 1979.
1980-06-01
Acta physica polonica , v. A55, no. 3, 1979, 307-318. (RZhRadiot, 10/79, lOYe3O) 237. Genin, L.G., S.M. Kuznetsov, and L.V. Sayenko (19). Study on heat...crystals by a Q-switched ruby laser. Acta Physica polonica , v. A55, no. 4, 1979, 531-543. (RZhF, 9/79, 9D1085) 572. Eichler, H.J., J. Eichler, J. Knof, and...N lasers, based on ceramic capacitors. Acta physica et 2- chemica. Szeged, no. 4, 1978, 445-449. (RZhF, 10/79, 10D1060) 2 64. Matyugin, Yu.A., and G.N
Lee, Yang-Sub
A time-domain numerical algorithm for solving the KZK (Khokhlov-Zabolotskaya-Kuznetsov) nonlinear parabolic wave equation is developed for pulsed, axisymmetric, finite amplitude sound beams in thermoviscous fluids. The KZK equation accounts for the combined effects of diffraction, absorption, and nonlinearity at the same order of approximation. The accuracy of the algorithm is established via comparison with analytical solutions for several limiting cases, and with numerical results obtained from a widely used algorithm for solving the KZK equation in the frequency domain. The time domain algorithm is used to investigate waveform distortion and shock formation in directive sound beams radiated by pulsed circular piston sources. New results include predictions for the entire process of self-demodulation, and for the effect of frequency modulation on pulse envelope distortion. Numerical results are compared with measurements, and focused sources are investigated briefly.
Derivation of nonlinear wave equations for ultrasound beam in nonuniform bubbly liquids
Kanagawa, Tetsuya; Yano, Takeru; Kawahara, Junya; Kobayashi, Kazumichi; Watanabe, Masao; Fujikawa, Shigeo
2012-09-01
Weakly nonlinear propagation of diffracted ultrasound beams in a nonuniform bubbly liquid is theoretically studied based on the method of multiple scales with the set of scaling relations of some physical parameters. It is assumed that the spatial distribution of the number density of bubbles in an initial state at rest is a slowly varying function of space coordinates and the amplitude of its variation is small compared with a mean number density. As a result, a Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation with dispersion and nonuniform effects for a low frequency case and a nonlinear Schrödinger (NLS) equation with dissipation, diffraction, and nonuniform effects for a high frequency case, are derived from the basic equations of bubbly flows.
Sound Beams with Shockwave Pulses
Enflo, B. O.
2000-11-01
The beam equation for a sound beam in a diffusive medium, called the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, has a class of solutions, which are power series in the transverse variable with the terms given by a solution of a generalized Burgers’ equation. A free parameter in this generalized Burgers’ equation can be chosen so that the equation describes an N-wave which does not decay. If the beam source has the form of a spherical cap, then a beam with a preserved shock can be prepared. This is done by satisfying an inequality containing the spherical radius, the N-wave pulse duration, the N-wave pulse amplitude, and the sound velocity in the fluid.
Soneson, Joshua E
2017-04-01
Wide-angle parabolic models are commonly used in geophysics and underwater acoustics but have seen little application in medical ultrasound. Here, a wide-angle model for continuous-wave high-intensity ultrasound beams is derived, which approximates the diffraction process more accurately than the commonly used Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation without increasing implementation complexity or computing time. A method for preventing the high spatial frequencies often present in source boundary conditions from corrupting the solution is presented. Simulations of shallowly focused axisymmetric beams using both the wide-angle and standard parabolic models are compared to assess the accuracy with which they model diffraction effects. The wide-angle model proposed here offers improved focusing accuracy and less error throughout the computational domain than the standard parabolic model, offering a facile method for extending the utility of existing KZK codes.
The pressure distribution for biharmonic transmitting array: theoretical study
Baranowska, A.
2005-03-01
The aim of the paper is theoretical analysis of the finite amplitude waves interaction problem for the biharmonic transmitting array. We assume that the array consists of 16 circular pistons of the same dimensions that regrouped in two sections. Two different arrangements of radiating elements were considered. In this situation the radiating surface is non-continuous without axial symmetry. The mathematical model was built on the basis of the Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation. To solve the problem the finite-difference method was applied. On-axis pressure amplitude for different frequency waves as a function of distance from the source, transverse pressure distribution of these waves at fixed distances from the source and pressure amplitude distribution for them at fixed planes were examined. Especially changes of normalized pressure amplitude for difference frequency were studied. The paper presents mathematical model and some results of theoretical investigations obtained for different values of source parameters.
A Simple Model for Nonlinear Confocal Ultrasonic Beams
Zhang, Dong; Zhou, Lin; Si, Li-Sheng; Gong, Xiu-Fen
2007-01-01
A confocally and coaxially arranged pair of focused transmitter and receiver represents one of the best geometries for medical ultrasonic imaging and non-invasive detection. We develop a simple theoretical model for describing the nonlinear propagation of a confocal ultrasonic beam in biological tissues. On the basis of the parabolic approximation and quasi-linear approximation, the nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation is solved by using the angular spectrum approach. Gaussian superposition technique is applied to simplify the solution, and an analytical solution for the second harmonics in the confocal ultrasonic beam is presented. Measurements are performed to examine the validity of the theoretical model. This model provides a preliminary model for acoustic nonlinear microscopy.
Modeling of Acoustic Field for a Parametric Focusing Source Using the Spheroidal Beam Equation
Yu Lili
2015-09-01
Full Text Available A theoretical model of acoustic field for a parametric focusing source on concave spherical surface is proposed. In this model, the source boundary conditions of the Spheroidal Beam Equation (SBE for difference frequency wave excitation were studied. Propagation curves and beam patterns for difference frequency component of the acoustic field are compared with those obtained for Khokhlov-Zabolotskaya-Kuznetsov (KZK model. The results demonstrate that the focused parametric model of SBE is good valid for a large aperture angle in the strongly focused acoustic field. It is also investigated that high directivity and good focal ability with the decreasing of downshift ratio and the increasing of half-aperture angle for the focused parametric model of SBE.
Multipulse technique exploiting the intermodulation of ultrasound waves in a nonlinear medium.
Biagi, Elena; Breschi, Luca; Vannacci, Enrico; Masotti, Leonardo
2009-03-01
In recent years, the nonlinear properties of materials have attracted much interest in nondestructive testing and in ultrasound diagnostic applications. Acoustic nonlinear parameters represent an opportunity to improve the information that can be extracted from a medium such as structural organization and pathologic status of tissue. In this paper, a method called pulse subtraction intermodulation (PSI), based on a multipulse technique, is presented and investigated both theoretically and experimentally. This method allows separation of the intermodulation products, which arise when 2 separate frequencies are transmitted in a nonlinear medium, from fundamental and second harmonic components, making them available for improved imaging techniques or signal processing algorithms devoted to tissue characterization. The theory of intermodulation product generation was developed according the Khokhlov-Zabolotskaya-Kuznetsov (KZK) nonlinear propagation equation, which is consistent with experimental results. The description of the proposed method, characterization of the intermodulation spectral contents, and quantitative results coming from in vitro experimentation are reported and discussed in this paper.
Model Equation for Acoustic Nonlinear Measurement of Dispersive Specimens at High Frequency
Zhang, Dong; Kushibiki, Junichi; Zou, Wei
2006-10-01
We present a theoretical model for acoustic nonlinearity measurement of dispersive specimens at high frequency. The nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation governs the nonlinear propagation in the SiO2/specimen/SiO2 multi-layer medium. The dispersion effect is considered in a special manner by introducing the frequency-dependant sound velocity in the KZK equation. Simple analytic solutions are derived by applying the superposition technique of Gaussian beams. The solutions are used to correct the diffraction and dispersion effects in the measurement of acoustic nonlinearity of cottonseed oil in the frequency range of 33-96 MHz. Regarding two different ultrasonic devices, the accuracies of the measurements are improved to ±2.0% and ±1.3% in comparison with ±9.8% and ±2.9% obtained from the previous plane wave model.
Effect of Micro-Bubbles in Water on Beam Patterns of Parametric Array
Hashiba, Kunio; Masuzawa, Hiroshi
2003-05-01
The improvement in efficiency of a parametric array by nonlinear oscillation of micro-bubbles in water is studied in this paper. The micro-bubble oscillation can increase the nonlinear coefficient of the acoustic medium. The amplitude of the difference-frequency wave along the longitudinal axis and its beam patterns in the field including the layer with micro-bubbles were analyzed using a Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation. As a result, the largest improvement in efficiency was obtained and a narrow parametric beam was formed by forming a layer with micro-bubbles in front of a parametric sound radiator as thick as about the shock formation distance. If the layer becomes significantly thicker than the distance, the beam of the difference-frequency wave in the far-field will become broader. If the layer is significantly thinner than the distance, the intensity level of the wave in the far-field will be too low.
Nonlinear propagation in ultrasonic fields: measurements, modelling and harmonic imaging.
Humphrey, V F
2000-03-01
In high amplitude ultrasonic fields, such as those used in medical ultrasound, nonlinear propagation can result in waveform distortion and the generation of harmonics of the initial frequency. In the nearfield of a transducer this process is complicated by diffraction effects associated with the source. The results of a programme to study the nonlinear propagation in the fields of circular, focused and rectangular transducers are described, and comparisons made with numerical predictions obtained using a finite difference solution to the Khokhlov-Zabolotskaya-Kuznetsov (or KZK) equation. These results are extended to consider nonlinear propagation in tissue-like media and the implications for ultrasonic measurements and ultrasonic heating are discussed. The narrower beamwidths and reduced side-lobe levels of the harmonic beams are illustrated and the use of harmonics to form diagnostic images with improved resolution is described.
Destrade, M.
2010-12-08
We study the propagation of two-dimensional finite-amplitude shear waves in a nonlinear pre-strained incompressible solid, and derive several asymptotic amplitude equations in a simple, consistent and rigorous manner. The scalar Zabolotskaya (Z) equation is shown to be the asymptotic limit of the equations of motion for all elastic generalized neo-Hookean solids (with strain energy depending only on the first principal invariant of Cauchy-Green strain). However, we show that the Z equation cannot be a scalar equation for the propagation of two-dimensional shear waves in general elastic materials (with strain energy depending on the first and second principal invariants of strain). Then, we introduce dispersive and dissipative terms to deduce the scalar Kadomtsev-Petviashvili (KP), Zabolotskaya-Khokhlov (ZK) and Khokhlov- Zabolotskaya-Kuznetsov (KZK) equations of incompressible solid mechanics. © 2010 The Royal Society.
Yu Lili; Shou Wende; Hui Chun
2012-01-01
A theoretical model of focused acoustic field for a multi-annular phased array on concave spherical surface is proposed. In this model, the source boundary conditions of the spheroidal beam equation (SBE) for multi-annular phased elements are studied. Acoustic field calculated by the dynamic focusing model of SBE is compared with numerical results of the O'Neil and Khokhlov-Zabolotskaya-Kuznetsov (KZK) model, respectively. Axial dynamic focusing and the harmonic effects are presented. The results demonstrate that the dynamic focusing model of SBE is good valid for a concave multi-annular phased array with a large aperture angle in the linear or nonlinear field. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Destrade, M.; Goriely, A.; Saccomandi, G.
2010-01-01
We study the propagation of two-dimensional finite-amplitude shear waves in a nonlinear pre-strained incompressible solid, and derive several asymptotic amplitude equations in a simple, consistent and rigorous manner. The scalar Zabolotskaya (Z) equation is shown to be the asymptotic limit of the equations of motion for all elastic generalized neo-Hookean solids (with strain energy depending only on the first principal invariant of Cauchy-Green strain). However, we show that the Z equation cannot be a scalar equation for the propagation of two-dimensional shear waves in general elastic materials (with strain energy depending on the first and second principal invariants of strain). Then, we introduce dispersive and dissipative terms to deduce the scalar Kadomtsev-Petviashvili (KP), Zabolotskaya-Khokhlov (ZK) and Khokhlov- Zabolotskaya-Kuznetsov (KZK) equations of incompressible solid mechanics. © 2010 The Royal Society.
RADIOCARBON CHRONOLOGY OF HOLOCENE PALSA OF BOL’SHEZEMEL’SKAYA TUNDRA IN RUSSIAN NORTH
Yurij Vasil’chuk
2013-01-01
Full Text Available Six palsa mire in Usa River valley and in Vorkuta area in North-eastern part of European Russia were studied in detail. In total 75 new 14C dates from different palsa sections were obtained. In palsa mire near Bugry Settlement 3.2 m high palsa dated from 8.6 to 2.1 ka BP. The permafrost and palsa began 2.1 ka BP. In palsa mire near Usa Settlement low moor peat in 2 m high palsa dated 3690 BP, palsa began to heave at least 3700 BP. A low-moor peat of 2.5 m high palsa indicates the change in the hydrological-mineral regime during 7.1 to 6.3 ka BP, heaving commenced 6 ka BP. A number of 8 14C dates from 5.6 to 2.7 ka BP obtained from peat of 3 m high palsa. Near Abez’ Settlement palsa development began about 2.8 ka BP. There are both large and smaller palsas. Low-moor peat of 3.5 m high palsa is dated between 9180 BP to 6730 BP near Nikita Settlement. In Vorkuta area near Khanovey Settlement the northern most palsa is found. The 14C age of peat at slope of the palsa is much younger, than in an axial part, there is inversion of the dates: the date 3.5 ka BP is between dates 2.9 and 2.8 ka BP. It is probably caused by creep of peat downwards from a summit. This evidenced this frozen mound is real palsa, but not a residual form as a result of erosion.
18th International Conference PhysicA.SPb
2016-01-01
Institute), Dr. Mikhail Dunaevskii (Ioffe Institute), Dr. Alexandra Kalashnikova (Ioffe Institute), Dr. Leonid Lutsev (Ioffe Institute). The Editors: Nikita S. Averkiev, Sergey A. Poniaev and Grigorii S. Sokolovskii (paper)
3D-radiative transfer in terrestrial atmosphere: An efficient parallel numerical procedure
Bass, L. P.; Germogenova, T. A.; Nikolaeva, O. V.; Kokhanovsky, A. A.; Kuznetsov, V. S.
2003-04-01
, V. V., 1972: Light scattering in planetary atmosphere, M.:Nauka. [2] Evans, K. F., 1998: The spherical harmonic discrete ordinate method for three dimensional atmospheric radiative transfer, J. Atmos. Sci., 55, 429 446. [3] L.P. Bass, T.A. Germogenova, V.S. Kuznetsov, O.V. Nikolaeva. RADUGA 5.1 and RADUGA 5.1(P) codes for stationary transport equation solution in 2D and 3D geometries on one and multiprocessors computers. Report on seminar “Algorithms and Codes for neutron physical of nuclear reactor calculations” (Neutronica 2001), Obninsk, Russia, 30 October 2 November 2001. [4] T.A. Germogenova, L.P. Bass, V.S. Kuznetsov, O.V. Nikolaeva. Mathematical modeling on parallel computers solar and laser radiation transport in 3D atmosphere. Report on International Symposium CIS countries “Atmosphere radiation”, 18 21 June 2002, St. Peterburg, Russia, p. 15 16. [5] L.P. Bass, T.A. Germogenova, O.V. Nikolaeva, V.S. Kuznetsov. Radiative Transfer Universal 2D 3D Code RADUGA 5.1(P) for Multiprocessor Computer. Abstract. Poster report on this Meeting. [6] L.P. Bass, O.V. Nikolaeva. Correct calculation of Angular Flux Distribution in Strongly Heterogeneous Media and Voids. Proc. of Joint International Conference on Mathematical Methods and Supercomputing for Nuclear Applications, Saratoga Springs, New York, October 5 9, 1997, p. 995 1004. [7] http://www/jscc.ru
Solar Flash Sub-Millimeter Wave Range Spectrum Part Radiation Modeling
V. Yu. Shustikov
2015-01-01
Full Text Available Currently, solar flares are under observation on the RT-7.5 radio telescope of BMSTU. This telescope operates in a little-studied range of the spectrum, at wavelengths of 3.2 and 2.2 mm (93 and 140 GHz, thereby providing unique information about parameters of the chromosphere plasma and zone of the temperature minimum. Observations on various instruments provided relatively small amount of data on the radio emission flare at frequencies close to 93 GHz, and at frequency of 140 GHz such observations were not carried out. For these reasons, data collected from the RT-7.5 radio telescope are of high value (Shustikov et al., 2012.This work describes modeling and gives interpretation of the reason for raising flux density spectrum of sub-millimeter radio frequency emission using as an example the GOES flare of class M 5.3 occurred on 04.07.2012 in the active region 11515. This flare was observed on the RT-7.5 radio telescope of BMSTU and was described by Shustikov et al. (2012 and by Smirnova et al. (2013, where it has been suggested that the reason for raising radio frequency emission is a bremsstrahlung of the thermal electrons in the hot plasma of the solar chromosphere. Rough estimates of the plasma temperature at the flare source were obtained.This paper proposes model calculations of the flux density spectrum of the sub-millimeter radio emission based on the gyrosynchrotron Fleischman-Kuznetsov code (Fleishman & Kuznetsov, 2010. Section 1 briefly describes observational data, tools and processing methods used in the work. Section 2 shows results of modeling the flare radio emission. Section 3 discusses results and conclusions.Numerical modeling the sub-millimeter part of the spectrum of the radio flux density for the GOES flare of class M5.3 has been carried out. This flare occurred in the active region 11515 on 04.07.2012. Modeling was based on the observations on the BMSTU’s RT-7.5 radio telescope.The paper draws conclusion based on the
Wahl, A. C. [Washington University, St. Louis, MO (United States)
1965-07-15
fragmentos de fision. Aunque muchos de los rendimientos calculados para los fragmentos primarios encierran considerables incertidumbres, debido principalmente a la falta de conocimientos sobre la distribucion de las cargas, en particular en el caso de productos de fision formados con un bajo rendimiento, el autor presenta algunos calculos de los rendimientos- primarios para destacar la necesidad de proseguir la labor de experimentacion y la posibilidad de hacerlo. Entre los procesos de fision que examina, ademas de la fision del {sup 235}U inducida por neutrones termicos, figuran los siguientes: fision del {sup 233}U y del {sup 239}Pu inducida por neutrones termicos, fision espontanea del {sup 240}Pu y del {sup 252}Cf, fision del {sup 235}U y del {sup 238}U inducida por neutrones de 14 MeV, fision del {sup 226}Ra inducida por protones de 11 MeV, y fision del {sup 209}Bi por deuterones de 22 MeV. (author) [Russian] Raspredelenija massy i zarjada pri delenii urana-235, vyzvannom teplovymi nejtronami dostatochno podrobno obsuzhdajutsja i sravnivajutsja zatem s sootvetstvujushhimi raspredelenijami pri drugih processah delenija, vyzvannogo chasticami nizkoj jenergii. V sostav voprosov, podlezhashhih obsuzhdeniju v svjazi s raspredelenijami mass pri delenii na dve chasti, vkljuchajutsja voprosy otnositel'no raspolozhenija pikov, vpadiny i tonkoj struktury krivoj vyhoda massy v otnoshenii zapolnennyh jadernyh obolochek i izmenenij v raspolozhenii, chto sluchaetsja pri izmenenii deljashhegosja jadra i jenergii vozbuzhdenija. Obsuzhdaetsja takzhe raspredelenie mass pri delenii jadra na tri chasti. Kak pri dvojnom, tak i pri trojnom delenii sdelany zamechanija otnositel'no raspredelenija mass pervichnyh oskolkov (do nejtronnoj jemissii) i produktov delenija (posle nejtronnoj jemissii). Raspredelenie zarjada obsuzhdaetsja v ramkah dispersii zarjada sredi produktov delenija s tem zhe massovym chislom i izmeneniem v massovom chisle Zp, ''naibolee verojatnyj zarjad'' (neintegral
Konecny, E.; Opower, H.; Guenther, H.; Goebel, H. [Physik-Department der Technischen Hochschule Muenchen, Munich and II. Physikalisches Institut der Justus Liebig-Universitaet Giessen, Federal Republic of Germany (Germany)
1965-07-15
vnimanie, no v otnoshenii ih legko vnesti sootvetstvujushhie popravki. Posle projavlenija jemul'sij vse beta-sledy, idushhie ot konca kazhdogo sleda oskolkov delenija, jasno vidny pod mikroskopom. Vozmozhnost' korreljacii kazhdogo otdel'nogo beta-sleda s opredelennym sledom oskolka delenija delaet vozmozhnym ustanovit' chislo p(h) oskolkov delenija, imejushhih ''h'' beta-sledy, chto daet ne tol'ko srednjuju dlinu cepochki, no takzhe raspredelenie beta-chastic. Tak kak ustojchivyj konechnyj produkt kazhdogo raspada v cepochke izvesten, to jeto raspredelenie beta-chastic javljaetsja tochnym izobrazheniem raspredelenija pervichnogo jadernogo zarjada. Pri izmerenijah, provodivshihsja do nastojashhego vremeni, registrirovalis' tol'ko beta-chasticy, izluchennye v polovine prostranstvennogo ugla, o'razovannogo jemul'sionnoj plastinkoj; odnako prostoj statisticheskij podschet daet vozmozhnost' ustanovit' zhelaemoe raspredelenie v geometrii 4{pi}. Na osnovanii jetogo metoda raspredelenija beta-chastic pri opredelennyh kineticheskih jenergijah, blizkih k srednej kineticheskoj jenergii kazhdoj massy oskolkov, dajutsja dlja mass 132, 134, 136 i 137. Dlja bolee nizkih iz jetih mass, , a imenno 132 i 134, nejtronnaja obolochka N = 82 opredeljaet naibolee verojatnye pervichnye zarjady sootvetstvenno okolo 50 i 52. Dlja M =136 i 137 pervichnyj zarjad sostavljaet okolo 53 i 53,2. Dopolnitel'nye priblizitel'nye popravki na jelektrony konversii (ne schitaja ochen' korotkih beta-sledov, sootvetstvujushhih ochen'malym beta-jenergijam) i na zapazdyvajushhie nejtrony (dlja massy 137) okazyvajutsja ne ochen' znachitel'nymi. V nastojashhee vremja podgotavlivajutsja analogichnye izmerenija neposredstvenno v geometrii 4{pi} vo izbezhanie statisticheskih pogreshnostej, voznikajushhih ot preobrazovanija raspredelenija 2{pi} v raspredelenie 4{pi} a takzhe dlja razlichnyh kineticheskih jenergij, prinimaemyh v kachestve parametrov. (author)
Walter, F J; Dabbs, J W.T.; Roberts, L D [Oak Ridge National Laboratory, Oak Ridge, TN (United States)
1962-04-15
ot detektora i usilitelya. Dlya bar'ernogo detektora s kremnievoj poverkhnost'yu v 40 mm{sup 2} pri 77{sup o}K. byli ustanovleny pokazateli shuma, ehkvivalentnye c {<=} 3 kehv (polnaya shirina pri polumaksimume). Poluprovodnikovym detektoram svojstvenen ''defekt amplitudy impul'sa'' dlya oskolkov deleniya. Imeyutsya dannye, svidetel'stvuyushchie o tom, chto ehtot defekt ne vyzyvaetsya ''neradioaktivnym sloem''. Esli ehlektricheskie polya, kotorye yavlyayutsya nedostatochnymi dlya obespecheniya polnogo ''sbora'', vyzyvayut ehtot defekt, neobkhodimym minimal'nym polem (na poverkhnosti) yavlyaetsya pole svyshe 3 x 10{sup 4} vol't/sm dlya oskolkov deleniya po sravneniyu c 2 x 10{sup 3} vol't/sm, neobkhodimost' chego byla ustanovlena dlya al'fa-chastits v germanii i kremnii. Podrobnye issledovaniya vremeni narastaniya impul'sa v usilitele pokazali, chto v materialakh s vysokoj soprotivlyaemost'yu kak vremya ''diehlektricheskoj'' relaksatsii, tak i soprotivlenie, svyazannoe s neistoshchennym osnovnym materialom, mogut igrat' vazhnuyu rol'. V doklade daetsya kolichestvennoe opisanie dejstviya parametrov detektora i usilitelya na formy i vremya narastaniya, svyazannye s impul'som. V doklade obsuzhdayutsya preimushchestva i problemy, svyazannye s ispol'zovaniem poverkhnostnykh bar'ernykh detektorov v nekotorykh opytakh po yadernomu vyravnivaniyu pri unikal'no nizkikh temperaturakh. V khode ehtikh opytov proiskhodili uglovye raspredeleniya oskolkov raspada i razreshenie al'fa-mikrostruktury s dolgosrochnoj stabil'nost'yu. V doklade takzhe daetsya opisanie tekhniki izgotovleniya s koehffitsientom soglasovannogo rasshireniya, kotoraya uspeshno ispol'zovalas' dlya izgotovleniya detektorov do 8 cm{sup 2} v aktivnoj zone. (author)
Kvitek, I.; Popov, Ju. P.; Rjabov, Ju. V. [Ob' edinennyj Institut Jadernyh Issledovanij, Dubna, SSSR (Russian Federation)
1965-07-15
de presion. La capa de {sup 235}U enriquecido, de {approx}2 mg/cm{sup 2} de espesor y de {approx}300 cm{sup 2} de superficie, se coloco sobre una lamina de aluminio de 20 {mu}m de espesor. En el volumen gaseoso situado de un lado de la lamina, se registraron los destellos de los fragmentos de fision, por el otro, los de las particulas ligeras de largo alcance. Para evaluar la actividad de fondo (por ejemplo, la coincidencia de los impulsos de un fragmento con el impulso de un cuanto gamma de fision o de un proton procedente de la reaccion (n, p) en la lamina de aluminio se efectuaron mediciones en las que el volumen en el que se registraban las particulas de largo alcance, se protegio mediante un filtro de aluminio suplementario de 1 mm de espesor. Los resultados del experimento indican que la razon entre las fisiones ternarias y binarias del {sup 235}U no acusa las fuertes variaciones sena ladas por otros autores. En las mediciones no se observo ninguna irregularidad en la razon de las secciones eficaces en el intervalo energetico 0,1 -0,2 eV. En la memoria se discute la posible influencia de la reaccion (n, {alpha}) sobre los resultados experimentales en los que no se ha recurrido a la coincidencia de las particulas de largo alcance con los fragmentos de fision. (author) [Russian] V poslednee vremja pojavilis' raboty, v kotoryh ukazyvalos' na sushhestvennye kolebanija otnoshenija sechenija trojnogo delenija k secheniju dvojnogo delenija urana-235 pri perehode odnogo nejtronnogo rezonansa k drugomu. V to zhe vremja dlja urana-235 i plutonija-239 takih kolebanij obnaruzheno ne bylo. V nastojashhem doklade soobshhaetsja ob issledovanijah trojnogo delenija urana-235 na nejtronah s jenergiej 0,1-30 jev. V otlichie ot drugih rabot po trojnomu deleniju urana-235 akt trojnogo delenija identificirovalsja po sovpadenijam odnogo iz oskolkov delenija s legkoj dlinnoprobezhnoj chasticej. Jeto pozvoljalo otdelit' trojnye delenija ot. vozmozhnogo vklada reakcii (n, {alpha
Liu Zongming; Duan Wenshan; He Guangjun
2008-01-01
A Zakharov-Kuznetsov (ZK) equation, a modified ZK (mZK) equation, and a coupled ZK (cZK) equation for small but finite amplitude dust acoustic waves in a magnetized two-ion-temperature dusty plasma with dust size distribution have been investigated in this paper. The variations of the linear dispersion relation and group velocity, nonlinear solitary wave amplitude, and width with an arbitrary dust size distribution function are studied numerically. We conclude that they all increase as the total number density of dust grains increases, and they are greater for unusual dusty plasma (the number density of larger dust grains is greater than that of smaller dust grains) than that of usual dusty plasma (the number density of smaller dust grains is greater than that of larger dust grains). It is noted that the frequency of the linear wave increases as the wave number along the magnetic direction increases. Furthermore, the width of the nonlinear waves increases but its amplitude decreases as the wave number along the magnetic direction increases
Club d'orientation
2014-01-01
Course d'orientation C’est sous un beau soleil samedi 4 octobre que s’est déroulée la 6e étape de la Coupe genevoise d’automne organisée par le club. Plus d’une centaine de concurrents provenant de 7 clubs de CO avaient fait le déplacement pour courir sur un des cinq parcours proposés dans les bois de Trélex-Génolier (VD). Le podium est le suivant : Technique long (5,9 km, 19 postes) : 1er Jurg Niggli, O’Jura (1:00:02); 2e Berni Wehrle, CO CERN (1:06:44); 3e Konrad Ehrbar, COLJ (1:07:08) Technique moyen (4,8 km, 18 postes) : 1er Christophe Vuitton, CO CERN (54:25); 2e J.B. Zosso, CO CERN (1:01:19); 3e Jeremy Wichoud, COLJ (1:06:21) Technique court (3,8 km, 14 postes) : 1er Julien Vuitton, CO CERN (36:19); 2e Vladimir Kuznetsov, COLJ (48:47); 3e Natalia Niggli, O’Jura (50:38) Facile moyen (3,2 km, 11 postes) : 1ère Alina Niggli, O&...
Club d'orientation du CERN
2015-01-01
Les coureurs d’orientation de la région se sont donné rendez-vous samedi dernier dans les bois de Pougny/Challex lors de l’épreuve organisée par le club d’orientation du CERN. La carte proposée pour les 5 circuits offrait aussi bien un coté très technique avec un relief pentu qu’un coté avec de grandes zones plates à forêt claire. Le parcours technique long comportant 20 postes a été remporté par Beat Muller du COLJ Lausanne en 56:26 devançant Denis Komarov, CO CERN en 57:30 et Yvan Balliot, ASO Annecy en 57:46. Pour les autres circuits les résultats sont les suivants: Technique moyen (13 postes): 1er Joël Mathieu en 52:32 à une seconde du 2e Vladimir Kuznetsov, COLJ Lausanne-Jorat, 3e Jean-Bernard Zosso, CO CERN, en 54:01 Technique court (12 postes): 1er Lennart Jirden, ...
Electrostatic structures associated with dusty electronegative magnetoplasmas
Moslem, W M; Abdelsalam, U M; Sabry, R; Shukla, P K
2010-01-01
By using the hydrodynamic equations of positive and negative ions, the Boltzmann electron density distribution and the Poisson equation with stationary dust, a three-dimensional (3D) Zakharov-Kuznetsov (ZK) equation is derived for small but finite amplitude ion-acoustic waves. However, the ZK equation is not appropriate to describe the system either at critical plasma compositions or in the vicinity of the critical plasma compositions. Therefore, the modified ZK (MZK) and extended ZK (EZK) equations are derived. The generalized expansion method is used to analytically solve the ZK, MZK and EZK equations. A new class of solutions that admits a train of well-separated bell-shaped periodic pulses is obtained. In certain conditions, the latter degenerates to either solitary or shock wave solutions. The effects of the physical parameters on the nonlinear structures are examined in many plasma environments having different negative ion species, such as D- and F-regions of the Earth's ionosphere, as well as in laboratory plasma experiments. Numerical analysis of the solutions revealed that the profile of the nonlinear pulses suffers amplitude and width modifications due to enhancement of the dust practices, negative ions, positive-to-negative ion mass ratio and positive/negative ion cyclotron frequency. Furthermore, the necessary conditions for both solitons and shocks propagation as well as their polarity are examined.
Bandyopadhyay, Anup; Das, K.P.
2002-01-01
The evolution equations describing both kinetic Alfven wave and ion-acoustic wave in a nonthermal magnetized plasma with warm ions including weak nonlinearity and weak dispersion with the effect of Landau damping have been derived. These equations reduce to two coupled equations constituting the KdV-ZK (Korteweg-de Vries-Zakharov-Kuznetsov) equation for both kinetic Alfven wave and ion-acoustic wave, including an extra term accounting for the effect of Landau damping. When the coefficient of the nonlinear term of the evolution equation for ion-acoustic wave vanishes, the nonlinear behavior of ion-acoustic wave, including the effect of Landau damping, is described by two coupled equations constituting the modified KdV-ZK (MKdV-ZK) equation, including an extra term accounting for the effect of Landau damping. It is found that there is no effect of Landau damping on the solitary structures of the kinetic Alfven wave. Both the macroscopic evolution equations for the ion-acoustic wave admits solitary wave solutions, the former having a sech 2 profile and the latter having a sech profile. In either case, it is found that the amplitude of the ion-acoustic solitary wave decreases slowly with time
Qin, Yan-Hong; Zhao, Li-Chen; Yang, Zhan-Ying; Yang, Wen-Li
2018-01-01
We investigate linear interference effects between a nonlinear plane wave and bright solitons, which are admitted by a pair-transition coupled two-component Bose-Einstein condensate. We demonstrate that the interference effects can induce several localized waves possessing distinctive wave structures, mainly including anti-dark solitons, W-shaped solitons, multi-peak solitons, Kuznetsov-Ma like breathers, and multi-peak breathers. Specifically, the explicit conditions for them are clarified by a phase diagram based on the linear interference properties. Furthermore, the interactions between these localized waves are discussed. The detailed analysis indicates that the soliton-soliton interaction induced phase shift brings the collision between these localized waves which can be inelastic for solitons involving collision and can be elastic for breathers. These characters come from the fact that the profile of solitons depends on the relative phase between bright solitons and a plane wave, and the profile of breathers does not depend on the relative phase. These results would motivate more discussions on linear interference between other nonlinear waves. Specifically, the solitons or breathers obtained here are not related to modulational instability. The underlying reasons are discussed in detail. In addition, possibilities to observe these localized waves are discussed in a two species Bose-Einstein condensate.
Kanagawa, Tetsuya
2015-05-01
This paper theoretically treats the weakly nonlinear propagation of diffracted sound beams in nonuniform bubbly liquids. The spatial distribution of the number density of the bubbles, initially in a quiescent state, is assumed to be a slowly varying function of the spatial coordinates; the amplitude of variation is assumed to be small compared to the mean number density. A previous derivation method of nonlinear wave equations for plane progressive waves in uniform bubbly liquids [Kanagawa, Yano, Watanabe, and Fujikawa (2010). J. Fluid Sci. Technol. 5(3), 351-369] is extended to handle quasi-plane beams in weakly nonuniform bubbly liquids. The diffraction effect is incorporated by adding a relation that scales the circular sound source diameter to the wavelength into the original set of scaling relations composed of nondimensional physical parameters. A set of basic equations for bubbly flows is composed of the averaged equations of mass and momentum, the Keller equation for bubble wall, and supplementary equations. As a result, two types of evolution equations, a nonlinear Schrödinger equation including dissipation, diffraction, and nonuniform effects for high-frequency short-wavelength case, and a Khokhlov-Zabolotskaya-Kuznetsov equation including dispersion and nonuniform effects for low-frequency long-wavelength case, are derived from the basic set.
Club d'Orientation
2011-01-01
Finale de la coupe genevoise d’automne Le club de CO du CERN a organisé samedi dernier la 10e et dernière étape de la saison. Cette course de type sprint a été remportée par Ville Keskisaari, COLJ, Gaëtan Vuitton, CO CERN, Franck Lonchampt, O’Jura respectivement sur les parcours technique long, moyen, et court. Victor Kuznetsov, COLJ a gagné sur le facile court, tout comme Nicolas Mueller, COLJ sur le facile moyen. Cette dernière course a permis aux participants de consolider ou d’améliorer leur place au classement général, et le podium, tenant compte des 6 meilleurs résultats de la saison, est le suivant : Technique long : 1er Jürg Niggli, O’Jura, 2e Christophe Vuitton, 3e Berni Wehrle. Technique moyen : 1er Gaëtan Vuitton, CO CERN, 2e Jean-Bernard Zosso, 3e Jean-Pierre Poncet. Technique court : 1er Fra...
Club d'Orientation
2012-01-01
Relais inter-club/Challenge Carlo Milan Samedi dernier, lors de l’épreuve de course d’orientation organisée par le club du O’Jura, le moteur de la discipline était l’esprit d’équipe, puisqu’il était question d’un relais inter-club avec le Challenge Carlo Milan. Les clubs avaient aligné leurs coureurs soit sur le relais technique (trois participants) soit sur le relais facile (deux participants). Côté O’Jura, il fallait noter la participation de François Gonon, champion du monde 2011, côté club du CERN, Marie et Gaëtan Vuitton, jeunes espoirs du club, devaient préparer la piste pour lancer le dernier relayeur. Côté Lausanne-Jorat, il fallait compter sur le très jeune Viktor Kuznetsov. Les 31 équipes engagées n’ont pas m&ea...
Le Club d’orientation du CERN
2017-01-01
COURSE ORIENTATION Finale de la coupe d’automne Le club d’orientation du CERN (COC Genève) a organisé sa dernière course populaire de la saison samedi 4 novembre au lieu-dit Les Terrasses de Genève (74). Cette 9e épreuve qui se courait sous la forme d’un One-Man-Relay, clôturait ainsi la coupe genevoise d’automne dont les lauréats sont : Circuit technique long : 1. Julien Vuitton (COC Genève), 2. Berni Wehrle (COC Genève), 3. Christophe Vuitton (COC Genève). Circuit technique moyen : 1. Vladimir Kuznetsov (Lausanne-Jorat), 2. J.-Bernard Zosso (COC Genève), 3. Laurent Merat (O’Jura). Circuit technique court : 1. Thibault Rouiller (COC Genève), 2. exæquo Lennart Jirden (COC Genève) et Katya Kuznetsova (Lausanne-Jorat). Circuit facile moyen : 1. Tituan Barge ...
Le Club d’orientation du CERN
2017-01-01
COURSE ORIENTATION Finale de la coupe d’automne Le club d’orientation du CERN (COC Genève) a organisé sa dernière course populaire de la saison samedi 4 novembre au lieu-dit Les Terrasses de Genève (74). Cette 9e épreuve qui se courait sous la forme d’un One-Man-Relay, clôturait ainsi la coupe genevoise d’automne dont les lauréats sont : Circuit technique long : 1. Julien Vuitton (COC Genève), 2. Berni Wehrle (COC Genève), 3. Christophe Vuitton (COC Genève). Circuit technique moyen : 1. Vladimir Kuznetsov (Lausanne-Jorat), 2. J.-Bernard Zosso (COC Genève), 3. Laurent Merat (O’Jura). Circuit technique court : 1. Thibault Rouiller (COC Genève), 2. exæquo Lennart Jirden (COC Genève) et Katya Kuznetsova (Lausanne-Jorat). Circuit facile moyen : 1. Tituan Barge...
Optimization Of Blasting Design Parameters On Open Pit Bench A Case Study Of Nchanga Open Pits
Victor Mwango Bowa
2015-08-01
Full Text Available Abstract In hard rock mining blasting is the most productive excavation technique applied to fragment insitu rock to the required size for efficient loading and crushing. In order to blast the insitu rock to the desired fragment size blast design parameter such as bench height hole diameter spacing burden hole length bottom charge specific charge and rock factor are considered. The research was carried out as a practical method on Nchanga Open Pits NOP ore Bench to optimize the blasting design parameters that can yield the required fragmentation size thereby reducing the shovel loading times and maximizing efficiency of the subsequent mining unit operations such as hauling and crushing. Fragmentation characteristics such as the mean fragment size were measured by means of a digital measuring tape and predicated using the Kuznetsov equation and rock factor value of ore bench was calculated using Lilly 1986 equations by means of rock characteristics. Traditional blasting design parameters were acquired for NOP and modified using Langerfors and Sharma P.A approaches. Several blast operations were conducted using both traditional and modified blasting design parameters on the same ore bench with the same geological conditions. Loading times of the shovel and fragment sizes were obtained after the blasts from ore bench where both the traditional and modified blasting design parameters were applied. Results show that mean fragment size and loading times were reduced from 51cm and 12minutes to 22cm and 3minutes where traditional and modified blasting design parameters were applied respectively.
Mahmood, S.; Sadiq, Safeer; Haque, Q.
2013-01-01
Linear and nonlinear electrostatic waves in magnetized dense electron-ion plasmas are studied with nonrelativistic and ultra-relativistic degenerate and singly, doubly charged helium (He + , He ++ ) and hydrogen (H + ) ions, respectively. The dispersion relation of electrostatic waves in magnetized dense plasmas is obtained under both the energy limits of degenerate electrons. Using reductive perturbation method, the Zakharov-Kuznetsov equation for nonlinear propagation of electrostatic solitons in magnetized dense plasmas is derived for both nonrelativistic and ultra-relativistic degenerate electrons. It is found that variations in plasma density, magnetic field intensity, different mass, and charge number of ions play significant role in the formation of electrostatic solitons in magnetized dense plasmas. The numerical plots are also presented for illustration using the parameters of dense astrophysical plasma situations such as white dwarfs and neutron stars exist in the literature. The present investigation is important for understanding the electrostatic waves propagation in the outer periphery of compact stars which mostly consists of hydrogen and helium ions with degenerate electrons in dense magnetized plasmas
Khan, Shahab Ullah; Adnan, Muhammad; Qamar, Anisa; Mahmood, Shahzad
2016-07-01
The propagation of linear and nonlinear electrostatic waves is investigated in magnetized dusty plasma with stationary negatively or positively charged dust, cold mobile ions and non-extensive electrons. Two normal modes are predicted in the linear regime, whose characteristics are investigated parametrically, focusing on the effect of electrons non-extensivity, dust charge polarity, concentration of dust and magnetic field strength. Using the reductive perturbation technique, a Zakharov-Kuznetsov (ZK) type equation is derived which governs the dynamics of small-amplitude solitary waves in magnetized dusty plasma. The properties of the solitary wave structures are analyzed numerically with the system parameters i.e. electrons non-extensivity, concentration of dust, polarity of dust and magnetic field strength. Following Allen and Rowlands (J. Plasma Phys. 53:63, 1995), we have shown that the pulse soliton solution of the ZK equation is unstable, and have analytically traced the dependence of the instability growth rate on the nonextensive parameter q for electrons, dust charge polarity and magnetic field strength. The results should be useful for understanding the nonlinear propagation of DIA solitary waves in laboratory and space plasmas.
Dust acoustic solitary and shock excitations in a Thomas-Fermi magnetoplasma
Rahim, Z.; Qamar, A. [Institute of Physics and Electronics, University of Peshawar, Peshawar 25000 (Pakistan); National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Ali, S. [National Center for Physics (NCP) at QAU Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)
2014-07-15
The linear and nonlinear properties of dust-acoustic waves are investigated in a collisionless Thomas-Fermi magnetoplasma, whose constituents are electrons, ions, and negatively charged dust particles. At dust time scale, the electron and ion number densities follow the Thomas-Fermi distribution, whereas the dust component is described by the classical fluid equations. A linear dispersion relation is analyzed to show that the wave frequencies associated with the upper and lower modes are enhanced with the variation of dust concentration. The effect of the latter is seen more strongly on the upper mode as compared to the lower mode. For nonlinear analysis, we obtain magnetized Korteweg-de Vries (KdV) and Zakharov-Kuznetsov (ZK) equations involving the dust-acoustic solitary waves in the framework of reductive perturbation technique. Furthermore, the shock wave excitations are also studied by allowing dissipation effects in the model, leading to the Korteweg-de Vries-Burgers (KdVB) and ZKB equations. The analysis reveals that the dust-acoustic solitary and shock excitations in a Thomas-Fermi plasma are strongly influenced by the plasma parameters, e.g., dust concentration, dust temperature, obliqueness, magnetic field strength, and dust fluid viscosity. The present results should be important for understanding the solitary and shock excitations in the environments of white dwarfs or supernova, where dust particles can exist.
Gupta, Samit Kumar
2018-03-01
Dynamic wave localization phenomena draw fundamental and technological interests in optics and photonics. Based on the recently proposed (Ablowitz and Musslimani, 2013) continuous nonlocal nonlinear Schrödinger system with parity-time symmetric Kerr nonlinearity (PTNLSE), a numerical investigation has been carried out for two first order Peregrine solitons as the initial ansatz. Peregrine soliton, as an exact solution to the PTNLSE, evokes a very potent question: what effects does the interaction of two first order Peregrine solitons have on the overall optical field dynamics. Upon numerical computation, we observe the appearance of Kuznetsov-Ma (KM) soliton trains in the unbroken PT-phase when the initial Peregrine solitons are in phase. In the out of phase condition, it shows repulsive nonlinear waves. Quite interestingly, our study shows that within a specific range of the interval factor in the transverse co-ordinate there exists a string of high intensity well-localized Peregrine rogue waves in the PT unbroken phase. We note that the interval factor as well as the transverse shift parameter play important roles in the nonlinear interaction and evolution dynamics of the optical fields. This could be important in developing fundamental understanding of nonlocal non-Hermitian NLSE systems and dynamic wave localization behaviors.
Rogoza AN
2012-05-01
Full Text Available Anatoliy N Rogoza,1 Aleksandr A Kuznetsov21Cardiology Research Complex, Moscow, Russian Federation; 2Therapy Research Institute, Siberian branch of Russian Academy of Medical Science, Novosibirsk, Russian FederationIntroduction: The aim of this study is the comparison of Vasotens® technology as used in a device with an oscillometric method of blood pressure measurement (BPLab, Petr Telegin Ltd, Nizhny Novgorod, Russian Federation against the validated tonometric system (SphygmoCor®, AtCor Medical Pty Ltd, West Ryde, Australia.Methods: The examinations were carried out in two medical centers. Exclusion criteria included atrial fibrillation, severe cardiac anomalies, heart failure, arrhythmia, decompensated diabetes, the presence of an artificial pacemaker, pregnancy, and BMI > 30. Overall, 160 patients and healthy volunteers were examined. Central aortic systolic blood pressure (aSBP and augmentation index (aAIx were obtained by means of applanation tonometry and the oscillometric method was compared.Results: aSBP and aAIx measured using the BPLab device equates significantly with the same parameters measured by SphygmoCor.Conclusion: This finding allows the recommendation of Vasotens technology, which can be used with the 24-hour BPLab monitoring system for wide clinical use.Keywords: central aortic blood pressure, augmentation index, validation, Vasotens®, BPLab®
Club d'orientation
2013-01-01
Courses d’orientation Samedi 20 avril, les organisateurs du Club de CO du CERN ont accueilli au Mont Mourex 70 participants qui n’ont pas hésité à venir malgré la forte bise. Berni Wehrle du CO CERN s’est octroyé la première place en 1:04:49 sur le parcours technique long devant Pyry Kettunen du Saynso Juankoski en 1:06:52, la 3e place revenant à Bruno Barge, CO CERN, à 7 secondes. Les autres parcours ont été remportés par : Technique moyen : 1er Jacques Moisset, Chamonix (47:44), 2e Yves Rousselot, Balise 25 Besançon (57:16), 3e Jean-Bernard Zosso, CO CERN (59:28). Technique court : 1er Victor Kuznetsov, COLJ (51:53), 2e Pierrick Collet, CO CERN (1:12:52), 3e Dominique Balay, CO CERN (1:16:04). Pour les parcours facile moyen et facile court, Ralf Nardini et Léa Nicolas, tous deux du CO CERN, terminaient respectivement premier. Voi...
Phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram
Zeng, K.J.; Haemaelaeinen, M.; Lilius, K.
1995-01-01
In the available experimental information on the Cu-Cr-Zr ternary system, there exist different opinions concerning the phase relationships in the Cu-rich corner of Cu-Cr-Zr phase diagram. Glazov et al. and Zakharov et al. investigated the Cu-rich corner of the Cu-Cr-Zr phase diagram within the composition range up to 3.5 Cr and 3.5 Zr (wt. %). A quasi-eutectic reaction L → (Cu) + αCr 2 Zr was observed to occur at 1,020 C and several isothermal sections were constructed within the temperature range from 600 to 1,000 C to show the (Cu)-αCr 2 Zr two phase equilibrium. Therefore, a pseudobinary Cu-Cr 2 Zr system was supposed. Afterwards, Dawakatsu et al, Fedorov et al, and Kuznetsov et al studied the cu-rich corner of the phase diagram in a wider composition range up to 5 Cr and 20 Zr (at.%). Contrary to Glazov et al. and Zakharov et al., they found no Cr 2 Zr phase in their samples. Hence, the pseudobinary Cu-Cr 2 Zr system does not exist. In this study an experimental investigation is presented on the phase relationships in Cu-rich corner of the Cu-Cr-Zr phase diagram at 940 C in order to clear up the confusion
EXCAVATION OF PITS (CHANNELS BY IMPACT OF PULSE POWER LOADING
Anakhaev Koshkinbai Nazirovich
2017-08-01
Full Text Available The paper provides an innovative hydromechanical solution of the problem of profiles development of pits and channels by impact of pulse (blasting power load on a surface of homogeneous soil mass, for example, when excavating solid rocks, frozen soil, etc. Thus, soil would be considered as an ideal heavy liquid (disregarding its mechanical strength and plastic properties. The solution of this problem is achieved by the method of consecutive conformal mappings of physical flow region (in the form of Kirchhoff complex on the region of complex potential (in the form of a rectangle. Thus, the new technique of geometrical image generation of the latter in the presence in the flow region of a fixed point with discontinuous variations of pressure head-flow function and the direction of speed of flow and representation of an elliptic sine of Jacobi by means of elementary functions are used. The received analytical functional dependencies allow to determine an outline of a funnel of the soil ejection and all the required hydromechanical characteristics of flow (head-flow function, function of flow, speed of flow, etc.. Thus, the soil ejection funnel outline (for a benchmark problem completely coincides with subproduct of the known rigorous solution of Lavrentyev-Kuznetsov.
Dust acoustic solitary and shock excitations in a Thomas-Fermi magnetoplasma
Rahim, Z.; Qamar, A.; Ali, S.
2014-01-01
The linear and nonlinear properties of dust-acoustic waves are investigated in a collisionless Thomas-Fermi magnetoplasma, whose constituents are electrons, ions, and negatively charged dust particles. At dust time scale, the electron and ion number densities follow the Thomas-Fermi distribution, whereas the dust component is described by the classical fluid equations. A linear dispersion relation is analyzed to show that the wave frequencies associated with the upper and lower modes are enhanced with the variation of dust concentration. The effect of the latter is seen more strongly on the upper mode as compared to the lower mode. For nonlinear analysis, we obtain magnetized Korteweg-de Vries (KdV) and Zakharov-Kuznetsov (ZK) equations involving the dust-acoustic solitary waves in the framework of reductive perturbation technique. Furthermore, the shock wave excitations are also studied by allowing dissipation effects in the model, leading to the Korteweg-de Vries-Burgers (KdVB) and ZKB equations. The analysis reveals that the dust-acoustic solitary and shock excitations in a Thomas-Fermi plasma are strongly influenced by the plasma parameters, e.g., dust concentration, dust temperature, obliqueness, magnetic field strength, and dust fluid viscosity. The present results should be important for understanding the solitary and shock excitations in the environments of white dwarfs or supernova, where dust particles can exist
The legal nature of the contract currency bank account
Ольга Олегівна Чорна
2016-06-01
Full Text Available The Civil Code of Ukraine there are no specific rules governing contractual relationship currency bank account, and existing norms in the national legislation does not reflect the specificity, complexity bank currency relations; regulations that regulate banking operations in foreign currencies, in some cases inconsistent, uncoordinated and even contradictory; In addition, some based on somewhat outdated today philosophical position, affecting the development bank currency civil relations. Problems about the determination of the legal nature of the contract currency bank account, studied and continue to study the eminent jurist scholars, among which highlight G.F. Shershenevich, C.A. Fleyshyts, I.B. Nowicki, M.N. Agarkova, A.S. Ioffe, N.S. Kuznetsov, I.A. Bezkluboho etc. Purpose of the article – the definition of the legal nature of the contract currency bank account, as well as research and analysis of major scientific debate on the subject. Given the inextricable link between the two elements of a bank account without connectivity relations on the account balance on any loan or of storage, believe that the bank account agreement today is an independent civil - legal contract.
Design of HIFU Transducers to Generate Specific Nonlinear Ultrasound Fields
Khokhlova, Vera A.; Yuldashev, Petr V.; Rosnitskiy, Pavel B.; Maxwell, Adam D.; Kreider, Wayne; Bailey, Michael R.; Sapozhnikov, Oleg A.
Various clinical applications of high intensity focused ultrasound (HIFU) have different requirements on the pressure level and degree of nonlinear waveform distortion at the focus. Applications that utilize nonlinear waves with developed shocks are of growing interest, for example, for mechanical disintegration as well as for accelerated thermal ablation oftissue. In this work, an inverse problem of determining transducer parameters to enable formation of shockswith desired amplitude at the focus is solved. The solution was obtained by performing multipledirect simulations of the parabolic Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for various parameters of the source. It is shown that results obtained within the parabolic approximation can be used to describe the focal region of single element spherical sourcesas well as complex transducer arrays. It is also demonstrated that the focal pressure level at which fully developed shocksare formed mainly depends on the focusing angle of the source and only slightly depends on its aperture and operating frequency. Using the simulation results, a 256-element HIFU array operating at 1.5 MHz frequency was designed for a specific application of boiling-histotripsy that relies on the presence of 90-100 MPa shocks at the focus. The size of the array elements and focusing angle of the array were chosen to satisfy technical limitations on the intensity at the array elements and desired shock amplitudes in the focal waveform. Focus steering capabilities of the array were analysed using an open-source T-Array software developed at Moscow State University.
Modeling of shock wave propagation in large amplitude ultrasound.
Pinton, Gianmarco F; Trahey, Gregg E
2008-01-01
The Rankine-Hugoniot relation for shock wave propagation describes the shock speed of a nonlinear wave. This paper investigates time-domain numerical methods that solve the nonlinear parabolic wave equation, or the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, and the conditions they require to satisfy the Rankine-Hugoniot relation. Two numerical methods commonly used in hyperbolic conservation laws are adapted to solve the KZK equation: Godunov's method and the monotonic upwind scheme for conservation laws (MUSCL). It is shown that they satisfy the Rankine-Hugoniot relation regardless of attenuation. These two methods are compared with the current implicit solution based method. When the attenuation is small, such as in water, the current method requires a degree of grid refinement that is computationally impractical. All three numerical methods are compared in simulations for lithotripters and high intensity focused ultrasound (HIFU) where the attenuation is small compared to the nonlinearity because much of the propagation occurs in water. The simulations are performed on grid sizes that are consistent with present-day computational resources but are not sufficiently refined for the current method to satisfy the Rankine-Hugoniot condition. It is shown that satisfying the Rankine-Hugoniot conditions has a significant impact on metrics relevant to lithotripsy (such as peak pressures) and HIFU (intensity). Because the Godunov and MUSCL schemes satisfy the Rankine-Hugoniot conditions on coarse grids, they are particularly advantageous for three-dimensional simulations.
Numerical Calculation and Measurement of Nonlinear Acoustic Fields in Ultrasound Diagnosis
Kawagishi, Tetsuya; Saito, Shigemi; Mine, Yoshitaka
2002-05-01
In order to develop a tool for designing on the ultrasonic probe and its peripheral devices for tissue-harmonic-imaging systems, a study is carried out to compare the calculation and observation results of nonlinear acoustic fields for a diagnostic ultrasound system. The pulsed ultrasound with a center frequency of 2.5 MHz is emanated from a weakly focusing sector probe with a 6.5 mm aperture radius and a 50 mm focal length into an agar phantom with an attenuation coefficient of about 0.6 dB/cm/MHz or 1.2 dB/cm/MHz. The nonlinear acoustic field is measured using a needle-type hydrophone. The calculation is based on the Khokhlov-Zabolotskaya-Kuznetsov(KZK) equation which is modified so that the frequency dependence of the attenuation coefficient is the same as that in biological tissue. This equation is numerically solved with the implicit backward method employing the iterative method. The measured and calculated amplitude spectra show good agreement with each other.
Gaussian representation of high-intensity focused ultrasound beams.
Soneson, Joshua E; Myers, Matthew R
2007-11-01
A method for fast numerical simulation of high-intensity focused ultrasound beams is derived. The method is based on the frequency-domain representation of the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, and assumes for each harmonic a Gaussian transverse pressure distribution at all distances from the transducer face. The beamwidths of the harmonics are constrained to vary inversely with the square root of the harmonic number, and as such this method may be viewed as an extension of a quasilinear approximation. The technique is capable of determining pressure or intensity fields of moderately nonlinear high-intensity focused ultrasound beams in water or biological tissue, usually requiring less than a minute of computer time on a modern workstation. Moreover, this method is particularly well suited to high-gain simulations since, unlike traditional finite-difference methods, it is not subject to resolution limitations in the transverse direction. Results are shown to be in reasonable agreement with numerical solutions of the full KZK equation in both tissue and water for moderately nonlinear beams.
Yuldashev, Petr V; Ollivier, Sébastien; Karzova, Maria M; Khokhlova, Vera A; Blanc-Benon, Philippe
2017-12-01
Linear and nonlinear propagation of high amplitude acoustic pulses through a turbulent layer in air is investigated using a two-dimensional KZK-type (Khokhlov-Zabolotskaya-Kuznetsov) equation. Initial waves are symmetrical N-waves with shock fronts of finite width. A modified von Kármán spectrum model is used to generate random wind velocity fluctuations associated with the turbulence. Physical parameters in simulations correspond to previous laboratory scale experiments where N-waves with 1.4 cm wavelength propagated through a turbulence layer with the outer scale of about 16 cm. Mean value and standard deviation of peak overpressure and shock steepness, as well as cumulative probabilities to observe amplified peak overpressure and shock steepness, are analyzed. Nonlinear propagation effects are shown to enhance pressure level in random foci for moderate initial amplitudes of N-waves thus increasing the probability to observe highly peaked waveforms. Saturation of the pressure level is observed for stronger nonlinear effects. It is shown that in the linear propagation regime, the turbulence mainly leads to the smearing of shock fronts, thus decreasing the probability to observe high values of steepness, whereas nonlinear effects dramatically increase the probability to observe steep shocks.
Fan, Tingbo; Liu, Zhenbo; Zhang, Dong; Tang, Mengxing
2013-03-01
Lesion formation and temperature distribution induced by high-intensity focused ultrasound (HIFU) were investigated both numerically and experimentally via two energy-delivering strategies, i.e., sequential discrete and continuous scanning modes. Simulations were presented based on the combination of Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation and bioheat equation. Measurements were performed on tissue-mimicking phantoms sonicated by a 1.12-MHz single-element focused transducer working at an acoustic power of 75 W. Both the simulated and experimental results show that, in the sequential discrete mode, obvious saw-tooth-like contours could be observed for the peak temperature distribution and the lesion boundaries, with the increasing interval space between two adjacent exposure points. In the continuous scanning mode, more uniform peak temperature distributions and lesion boundaries would be produced, and the peak temperature values would decrease significantly with the increasing scanning speed. In addition, compared to the sequential discrete mode, the continuous scanning mode could achieve higher treatment efficiency (lesion area generated per second) with a lower peak temperature. The present studies suggest that the peak temperature and tissue lesion resulting from the HIFU exposure could be controlled by adjusting the transducer scanning speed, which is important for improving the HIFU treatment efficiency.
Hydrophone area-averaging correction factors in nonlinearly generated ultrasonic beams
Cooling, M P; Humphrey, V F; Wilkens, V
2011-01-01
The nonlinear propagation of an ultrasonic wave can be used to produce a wavefield rich in higher frequency components that is ideally suited to the calibration, or inter-calibration, of hydrophones. These techniques usually use a tone-burst signal, limiting the measurements to harmonics of the fundamental calibration frequency. Alternatively, using a short pulse enables calibration at a continuous spectrum of frequencies. Such a technique is used at PTB in conjunction with an optical measurement technique to calibrate devices. Experimental findings indicate that the area-averaging correction factor for a hydrophone in such a field demonstrates a complex behaviour, most notably varying periodically between frequencies that are harmonics of the centre frequency of the original pulse and frequencies that lie midway between these harmonics. The beam characteristics of such nonlinearly generated fields have been investigated using a finite difference solution to the nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for a focused field. The simulation results are used to calculate the hydrophone area-averaging correction factors for 0.2 mm and 0.5 mm devices. The results clearly demonstrate a number of significant features observed in the experimental investigations, including the variation with frequency, drive level and hydrophone element size. An explanation for these effects is also proposed.
Fan, Tingbo; Liu, Zhenbo; Chen, Tao; Li, Faqi; Zhang, Dong
2011-09-01
In this work, the authors propose a modeling approach to compute the nonlinear acoustic field generated by a flat piston transmitter with an attached aluminum lens. In this approach, the geometrical parameters (radius and focal length) of a virtual source are initially determined by Snell's refraction law and then adjusted based on the Rayleigh integral result in the linear case. Then, this virtual source is used with the nonlinear spheroidal beam equation (SBE) model to predict the nonlinear acoustic field in the focal region. To examine the validity of this approach, the calculated nonlinear result is compared with those from the Westervelt and (Khokhlov-Zabolotskaya-Kuznetsov) KZK equations for a focal intensity of 7 kW/cm(2). Results indicate that this approach could accurately describe the nonlinear acoustic field in the focal region with less computation time. The proposed modeling approach is shown to accurately describe the nonlinear acoustic field in the focal region. Compared with the Westervelt equation, the computation time of this approach is significantly reduced. It might also be applicable for the widely used concave focused transmitter with a large aperture angle.
Shan, Feng; Guo, Xiasheng; Tu, Juan; Cheng, Jianchun; Zhang, Dong
The high-intensity focused ultrasound (HIFU) has become an attractive therapeutic tool for the noninvasive tumor treatment. The ultrasonic transducer is the key component in HIFU treatment to generate the HIFU energy. The dimension of focal region generated by the transducer is closely relevant to the safety of HIFU treatment. Therefore, it is essential to numerically investigate the focal region of the transducer. Although the conventional acoustic wave equations have been used successfully to describe the acoustic field, there still exist some inherent drawbacks. In this work, we presented an axisymmetric isothermal multi-relaxation-time lattice Boltzmann method (MRT-LBM) model with the Bouzidi-Firdaouss-Lallemand (BFL) boundary condition in cylindrical coordinate system. With this model, some preliminary simulations were firstly conducted to determine a reasonable value of the relaxation parameter. Then, the validity of the model was examined by comparing the results obtained with the LBM results with the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation and the Spheroidal beam equation (SBE) for the focused transducers with different aperture angles, respectively. In addition, the influences of the aperture angle on the focal region were investigated. The proposed model in this work will provide significant references for the parameter optimization of the focused transducer for applications in the HIFU treatment or other fields, and provide new insights into the conventional acoustic numerical simulations.
Bleeker, H J; Lewin, P A
2000-01-01
A new calibration technique for PVDF ultrasonic hydrophone probes is described. Current implementation of the technique allows determination of hydrophone frequency response between 2 and 100 MHz and is based on the comparison of theoretically predicted and experimentally determined pressure-time waveforms produced by a focused, circular source. The simulation model was derived from the time domain algorithm that solves the non linear KZK (Khokhlov-Zabolotskaya-Kuznetsov) equation describing acoustic wave propagation. The calibration technique data were experimentally verified using independent calibration procedures in the frequency range from 2 to 40 MHz using a combined time delay spectrometry and reciprocity approach or calibration data provided by the National Physical Laboratory (NPL), UK. The results of verification indicated good agreement between the results obtained using KZK and the above-mentioned independent calibration techniques from 2 to 40 MHz, with the maximum discrepancy of 18% at 30 MHz. The frequency responses obtained using different hydrophone designs, including several membrane and needle probes, are presented, and it is shown that the technique developed provides a desirable tool for independent verification of primary calibration techniques such as those based on optical interferometry. Fundamental limitations of the presented calibration method are also examined.
Measurement and numerical simulation of high intensity focused ultrasound field in water
Lee, Kang Il
2017-11-01
In the present study, the acoustic field of a high intensity focused ultrasound (HIFU) transducer in water was measured by using a commercially available needle hydrophone intended for HIFU use. To validate the results of hydrophone measurements, numerical simulations of HIFU fields were performed by integrating the axisymmetric Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation from the frequency-domain perspective with the help of a MATLAB-based software package developed for HIFU simulation. Quantitative values for the focal waveforms, the peak pressures, and the size of the focal spot were obtained in various regimes of linear, quasilinear, and nonlinear propagation up to the source pressure levels when the shock front was formed in the waveform. The numerical results with the HIFU simulator solving the KZK equation were compared with the experimental data and found to be in good agreement. This confirms that the numerical simulation based on the KZK equation is capable of capturing the nonlinear pressure field of therapeutic HIFU transducers well enough to make it suitable for HIFU treatment planning.
Hydrophone area-averaging correction factors in nonlinearly generated ultrasonic beams
Cooling, M. P.; Humphrey, V. F.; Wilkens, V.
2011-02-01
The nonlinear propagation of an ultrasonic wave can be used to produce a wavefield rich in higher frequency components that is ideally suited to the calibration, or inter-calibration, of hydrophones. These techniques usually use a tone-burst signal, limiting the measurements to harmonics of the fundamental calibration frequency. Alternatively, using a short pulse enables calibration at a continuous spectrum of frequencies. Such a technique is used at PTB in conjunction with an optical measurement technique to calibrate devices. Experimental findings indicate that the area-averaging correction factor for a hydrophone in such a field demonstrates a complex behaviour, most notably varying periodically between frequencies that are harmonics of the centre frequency of the original pulse and frequencies that lie midway between these harmonics. The beam characteristics of such nonlinearly generated fields have been investigated using a finite difference solution to the nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for a focused field. The simulation results are used to calculate the hydrophone area-averaging correction factors for 0.2 mm and 0.5 mm devices. The results clearly demonstrate a number of significant features observed in the experimental investigations, including the variation with frequency, drive level and hydrophone element size. An explanation for these effects is also proposed.
Hasani, Mojtaba H; Gharibzadeh, Shahriar; Farjami, Yaghoub; Tavakkoli, Jahan
2013-09-01
Various numerical algorithms have been developed to solve the Khokhlov-Kuznetsov-Zabolotskaya (KZK) parabolic nonlinear wave equation. In this work, a generalized time-domain numerical algorithm is proposed to solve the diffraction term of the KZK equation. This algorithm solves the transverse Laplacian operator of the KZK equation in three-dimensional (3D) Cartesian coordinates using a finite-difference method based on the five-point implicit backward finite difference and the five-point Crank-Nicolson finite difference discretization techniques. This leads to a more uniform discretization of the Laplacian operator which in turn results in fewer calculation gridding nodes without compromising accuracy in the diffraction term. In addition, a new empirical algorithm based on the LU decomposition technique is proposed to solve the system of linear equations obtained from this discretization. The proposed empirical algorithm improves the calculation speed and memory usage, while the order of computational complexity remains linear in calculation of the diffraction term in the KZK equation. For evaluating the accuracy of the proposed algorithm, two previously published algorithms are used as comparison references: the conventional 2D Texas code and its generalization for 3D geometries. The results show that the accuracy/efficiency performance of the proposed algorithm is comparable with the established time-domain methods.
Nonlinear magnetoacoustic wave propagation with chemical reactions
Margulies, Timothy Scott
2002-11-01
The magnetoacoustic problem with an application to sound wave propagation through electrically conducting fluids such as the ocean in the Earth's magnetic field, liquid metals, or plasmas has been addressed taking into account several simultaneous chemical reactions. Using continuum balance equations for the total mass, linear momentum, energy; as well as Maxwell's electrodynamic equations, a nonlinear beam equation has been developed to generalize the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation for a fluid with linear viscosity but nonlinear and diffraction effects. Thermodynamic parameters are used and not tailored to only an adiabatic fluid case. The chemical kinetic equations build on a relaxing media approach presented, for example, by K. Naugolnukh and L. Ostrovsky [Nonlinear Wave Processes in Acoustics (Cambridge Univ. Press, Cambridge, 1998)] for a linearized single reaction and thermodynamic pressure equation of state. Approximations for large and small relaxation times and for magnetohydrodynamic parameters [Korsunskii, Sov. Phys. Acoust. 36 (1990)] are examined. Additionally, Cattaneo's equation for heat conduction and its generalization for a memory process rather than a Fourier's law are taken into account. It was introduced for the heat flux depends on the temperature gradient at an earlier time to generate heat pulses of finite speed.
New analytical exact solutions of time fractional KdV-KZK equation by Kudryashov methods
S Saha, Ray
2016-04-01
In this paper, new exact solutions of the time fractional KdV-Khokhlov-Zabolotskaya-Kuznetsov (KdV-KZK) equation are obtained by the classical Kudryashov method and modified Kudryashov method respectively. For this purpose, the modified Riemann-Liouville derivative is used to convert the nonlinear time fractional KdV-KZK equation into the nonlinear ordinary differential equation. In the present analysis, the classical Kudryashov method and modified Kudryashov method are both used successively to compute the analytical solutions of the time fractional KdV-KZK equation. As a result, new exact solutions involving the symmetrical Fibonacci function, hyperbolic function and exponential function are obtained for the first time. The methods under consideration are reliable and efficient, and can be used as an alternative to establish new exact solutions of different types of fractional differential equations arising from mathematical physics. The obtained results are exhibited graphically in order to demonstrate the efficiencies and applicabilities of these proposed methods of solving the nonlinear time fractional KdV-KZK equation.
Intensity dependence of focused ultrasound lesion position
Meaney, Paul M.; Cahill, Mark D.; ter Haar, Gail R.
1998-04-01
Knowledge of the spatial distribution of intensity loss from an ultrasonic beam is critical to predicting lesion formation in focused ultrasound surgery. To date most models have used linear propagation models to predict the intensity profiles needed to compute the temporally varying temperature distributions. These can be used to compute thermal dose contours that can in turn be used to predict the extent of thermal damage. However, these simulations fail to adequately describe the abnormal lesion formation behavior observed for in vitro experiments in cases where the transducer drive levels are varied over a wide range. For these experiments, the extent of thermal damage has been observed to move significantly closer to the transducer with increasing transducer drive levels than would be predicted using linear propagation models. The simulations described herein, utilize the KZK (Khokhlov-Zabolotskaya-Kuznetsov) nonlinear propagation model with the parabolic approximation for highly focused ultrasound waves, to demonstrate that the positions of the peak intensity and the lesion do indeed move closer to the transducer. This illustrates that for accurate modeling of heating during FUS, nonlinear effects must be considered.
Design of HIFU Transducers for Generating Specified Nonlinear Ultrasound Fields.
Rosnitskiy, Pavel B; Yuldashev, Petr V; Sapozhnikov, Oleg A; Maxwell, Adam D; Kreider, Wayne; Bailey, Michael R; Khokhlova, Vera A
2017-02-01
Various clinical applications of high-intensity focused ultrasound have different requirements for the pressure levels and degree of nonlinear waveform distortion at the focus. The goal of this paper is to determine transducer design parameters that produce either a specified shock amplitude in the focal waveform or specified peak pressures while still maintaining quasi-linear conditions at the focus. Multiparametric nonlinear modeling based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation with an equivalent source boundary condition was employed. Peak pressures, shock amplitudes at the focus, and corresponding source outputs were determined for different transducer geometries and levels of nonlinear distortion. The results are presented in terms of the parameters of an equivalent single-element spherically shaped transducer. The accuracy of the method and its applicability to cases of strongly focused transducers were validated by comparing the KZK modeling data with measurements and nonlinear full diffraction simulations for a single-element source and arrays with 7 and 256 elements. The results provide look-up data for evaluating nonlinear distortions at the focus of existing therapeutic systems as well as for guiding the design of new transducers that generate specified nonlinear fields.
Jiménez, Noé; Camarena, Francisco; Redondo, Javier; Sánchez-Morcillo, Víctor; Konofagou, Elisa E.
2015-10-01
We report a numerical method for solving the constitutive relations of nonlinear acoustics, where multiple relaxation processes are included in a generalized formulation that allows the time-domain numerical solution by an explicit finite differences scheme. Thus, the proposed physical model overcomes the limitations of the one-way Khokhlov-Zabolotskaya-Kuznetsov (KZK) type models and, due to the Lagrangian density is implicitly included in the calculation, the proposed method also overcomes the limitations of Westervelt equation in complex configurations for medical ultrasound. In order to model frequency power law attenuation and dispersion, such as observed in biological media, the relaxation parameters are fitted to both exact frequency power law attenuation/dispersion media and also empirically measured attenuation of a variety of tissues that does not fit an exact power law. Finally, a computational technique based on artificial relaxation is included to correct the non-negligible numerical dispersion of the finite difference scheme, and, on the other hand, improve stability trough artificial attenuation when shock waves are present. This technique avoids the use of high-order finite-differences schemes leading to fast calculations. The present algorithm is especially suited for practical configuration where spatial discontinuities are present in the domain (e.g. axisymmetric domains or zero normal velocity boundary conditions in general). The accuracy of the method is discussed by comparing the proposed simulation solutions to one dimensional analytical and k-space numerical solutions.
Sapozhnikov, Oleg A.; Khokhlova, Vera A.; Cathignol, Dominique
2004-05-01
A classical effect of nonlinear acoustics is that a plane sinusoidal acoustic wave propagating in a nonlinear medium transforms to a sawtooth wave with one shock per cycle. However, the waveform evolution can be quite different in the near field of a plane source due to diffraction. Previous numerical simulations of nonlinear acoustic waves in the near field of a circular piston source predict the development of two shocks per wave cycle [Khokhlova et al., J. Acoust. Soc. Am. 110, 95-108 (2001)]. Moreover, at some locations the peak pressure may be up to 4 times the source amplitude. The motivation of this work was to experimentally verify and further explain the phenomena of the nonlinear waveform distortion. Measurements were conducted in water with a 47-mm-diameter unfocused transducer, working at 1-MHz frequency. For pressure amplitudes higher than 0.5 MPa, two shocks per cycle were observed in the waveform beyond the last minimum of the fundamental harmonic amplitude. With the increase of the observation distance, these two shocks collided and formed one shock (per cycle), i.e., the waveform developed into the classical sawtooth wave. The experimental results were in a very good agreement with the modeling based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation.
Nonlinear and diffraction effects in propagation of N-waves in randomly inhomogeneous moving media.
Averiyanov, Mikhail; Blanc-Benon, Philippe; Cleveland, Robin O; Khokhlova, Vera
2011-04-01
Finite amplitude acoustic wave propagation through atmospheric turbulence is modeled using a Khokhlov-Zabolotskaya-Kuznetsov (KZK)-type equation. The equation accounts for the combined effects of nonlinearity, diffraction, absorption, and vectorial inhomogeneities of the medium. A numerical algorithm is developed which uses a shock capturing scheme to reduce the number of temporal grid points. The inhomogeneous medium is modeled using random Fourier modes technique. Propagation of N-waves through the medium produces regions of focusing and defocusing that is consistent with geometrical ray theory. However, differences up to ten wavelengths are observed in the locations of fist foci. Nonlinear effects are shown to enhance local focusing, increase the maximum peak pressure (up to 60%), and decrease the shock rise time (about 30 times). Although the peak pressure increases and the rise time decreases in focal regions, statistical analysis across the entire wavefront at a distance 120 wavelengths from the source indicates that turbulence: decreases the mean time-of-flight by 15% of a pulse duration, decreases the mean peak pressure by 6%, and increases the mean rise time by almost 100%. The peak pressure and the arrival time are primarily governed by large scale inhomogeneities, while the rise time is also sensitive to small scales.
New analytical exact solutions of time fractional KdV–KZK equation by Kudryashov methods
Saha Ray, S
2016-01-01
In this paper, new exact solutions of the time fractional KdV–Khokhlov–Zabolotskaya–Kuznetsov (KdV–KZK) equation are obtained by the classical Kudryashov method and modified Kudryashov method respectively. For this purpose, the modified Riemann–Liouville derivative is used to convert the nonlinear time fractional KdV–KZK equation into the nonlinear ordinary differential equation. In the present analysis, the classical Kudryashov method and modified Kudryashov method are both used successively to compute the analytical solutions of the time fractional KdV–KZK equation. As a result, new exact solutions involving the symmetrical Fibonacci function, hyperbolic function and exponential function are obtained for the first time. The methods under consideration are reliable and efficient, and can be used as an alternative to establish new exact solutions of different types of fractional differential equations arising from mathematical physics. The obtained results are exhibited graphically in order to demonstrate the efficiencies and applicabilities of these proposed methods of solving the nonlinear time fractional KdV–KZK equation. (paper)
Propagation of three-dimensional electron-acoustic solitary waves
Shalaby, M.; El-Sherif, L. S.; El-Labany, S. K.; Sabry, R.
2011-01-01
Theoretical investigation is carried out for understanding the properties of three-dimensional electron-acoustic waves propagating in magnetized plasma whose constituents are cold magnetized electron fluid, hot electrons obeying nonthermal distribution, and stationary ions. For this purpose, the hydrodynamic equations for the cold magnetized electron fluid, nonthermal electron density distribution, and the Poisson equation are used to derive the corresponding nonlinear evolution equation, Zkharov-Kuznetsov (ZK) equation, in the small- but finite- amplitude regime. The ZK equation is solved analytically and it is found that it supports both solitary and blow-up solutions. It is found that rarefactive electron-acoustic solitary waves strongly depend on the density and temperature ratios of the hot-to-cold electron species as well as the nonthermal electron parameter. Furthermore, there is a critical value for the nonthermal electron parameter, which decides whether the electron-acoustic solitary wave's amplitude is decreased or increased by changing various plasma parameters. Importantly, the change of the propagation angles leads to miss the balance between the nonlinearity and dispersion; hence, the localized pulses convert to explosive/blow-up pulses. The relevance of this study to the nonlinear electron-acoustic structures in the dayside auroral zone in the light of Viking satellite observations is discussed.
Influence of joint direction and position of explosive charge on fragmentation
Hafsaoui, Abdellah; Talhi, Korichi
2009-01-01
Although researchers have realized varying degrees of success in small-scale physical in situ testing, most will agree that the greatest uncertainty stems from the uncontrollable field variables. Given the diverse nature of field conditions encountered, there exists no reliable and proven method of predicting fragmentation. Due to the lack of adequate field controls, it is unlikely that a universal physical model will ever be developed for all blasting. This paper presents the results of a test conducted at the Hadjar Essoud quarry to investigate the problems associated with the discontinuities in the rock, which are among the factors causing the reduction of the resistance of the rocks to the explosive. Nevertheless, the distance between the joints, their dip and strike, and the position of the detonator play a significant role in the final fragmentation of the rock. In this work, we studied the role of the abovementioned factors on models of limestone rock of 150 X 375 X 450 mm. Accurate measurement of blast, fragmentation is important in mining and quarrying operations, in monitoring blasts, and optimizing their design. We shall use the Kuznetsov-Rammler method to measure fragmentation. It shows great potential as a practical aid to predict and control the quality of the fragmented material in the Hadjar Essoud quarry. (author)
Rasmussen, Anders Rønne; Sørensen, Mads Peter; Gaididei, Yuri Borisovich
2011-01-01
A wave equation including nonlinear terms up to the second order for a thermoviscous Newtonian fluid is proposed. In the lossless case this equation results from an expansion to third order of the Lagrangian for the fundamental non-dissipative fluid dynamical equations. Thus it preserves the Hami...... is proposed. The dynamics of the rarefaction wave is approximated by a collective coordinate approach in the energy balance equation. © 2010 Springer Science+Business Media B.V.......A wave equation including nonlinear terms up to the second order for a thermoviscous Newtonian fluid is proposed. In the lossless case this equation results from an expansion to third order of the Lagrangian for the fundamental non-dissipative fluid dynamical equations. Thus it preserves...... the Hamiltonian structure, in contrast to the Kuznetsov equation, a model often used in nonlinear acoustics. An exact traveling wave front solution is derived from a generalized traveling wave assumption for the velocity potential. Numerical studies of the evolution of a number of arbitrary initial conditions...
Ever Ready to Go: The Multiple Exiles of Leo Szilard
Frank, Tibor
2005-06-01
aging. In 1956 von Laue led an effort to invite him to head a new institute for nuclear physics in West Berlin, which he ultimately declined at the end of 1959. He remained in the United States, becoming a highly visible public figure, speaking, writing, and traveling extensively, and even corresponding with Soviet Premier Nikita S.Khrushchev and President John F. Kennedy to promote the international control of nuclear weapons. In retrospect, although Szilard was a man of many missions, his life story could be read as that of a man of conscience with but a single mission, to save mankind.
2014-09-01
Dear Colleagues, 1st International School and Conference "Saint Petersburg OPEN 2014" on Optoelectronics, Photonics, Engineering and Nanostructures was held on March 25 - 27, 2014 at St. Petersburg Academic University - Nanotechnology Research and Education Centre of the Russian Academy of Sciences. The School and Conference included a series of invited talks given by leading professors with the aim to introduce young scientists with actual problems and major advances in physics and technology. The keynote speakers were: Mikhail Glazov (Ioffe Physico-Technical Institute RAS, Russia) Vladimir Dubrovskii (Saint Petersburg Academic University RAS, Russia) Alexey Kavokin (University of Southampton, United Kingdom and St. Petersburg State University, Russia) Vladimir Korenev (Ioffe Physico-Technical Institute RAS, Russia) Sergey Kukushkin (Institute of Problems of Mechanical Engineering RAS, Russia) Nikita Pikhtin (Ioffe Physico-Technical Institute RAS, Russia and "Elfolum" Ltd., Russia) Dmitry Firsov (Saint Petersburg State Polytechnical University, Russia) During the poster session all undergraduate and graduate students attending the conference presented their works. Sufficiently large number of participants with more than 160 student attendees from all over the world allowed the Conference to provide a fertile ground for the fruitful discussions between the young scientists as well as to become a perfect platform for the valuable discussions between student authors and highly experienced scientists. The best student papers, which were selected by the Program Committee and by the invited speakers basing on the theses and their poster presentation, were awarded with diplomas of the conference - see the photos. This year's School and Conference is supported by SPIE (The International Society for Optics and Photonics), OSA (The Optical Society), St. Petersburg State Polytechnical University and by Skolkovo Foundation. It is a continuation of the annual schools and
Vassilios P Kozobolis
2010-08-01
Full Text Available Vassilios P Kozobolis, Eleftherios I Paschalis, Nikitas C Foudoulakis, Stavrenia C Koukoula, Georgios LabirisDepartment of Ophthalmology and Eye Institute of Thrace, Democritus University of Thrace, Alexandroupolis, GreecePurpose: To develop, characterize, and validate a prototype digital aqueous humor outflow tonographer (DAHOM.Material and methods: The DAHOM was developed, characterized, and validated in three phases. Phase 1 involved construction of the sensor. This was broadly based on the fundamental design of a typical Schiotz tonographer with a series of improvements, including corneal indentation, which was converted to an electrical signal via a linear variable differential transducer, an analog signal which was converted to digital via ADC circuitry, and digital data acquisition and processing which was made possible by a serial port interface. Phase 2 comprised development of software for automated assessment of the outflow facility. Automated outflow facility assessment incorporated a series of fundamental improvements in comparison with traditional techniques, including software-based filtering of ripple noise and extreme variations, rigidity impact analysis, and evaluation of the impact of patient age, central corneal thickness, and ocular axial length. Phase 3 comprised characterization and validation of DAHOM, for which we developed an experimental setup using porcine cadaver eyes. DAHOM’s repeatability was evaluated by means of Cronbach’s alpha and intraclass correlation coefficient. The level of agreement with a standard Schiotz tonographer was evaluated by means of paired t-tests and Bland-Altman analysis in human eyes.Results: The experimental setup provided the necessary data for the characterization of DAHOM. A fourth order polynomial equation provided excellent fit (R square >0.999. DAHOM demonstrated high repeatability (Cronbach’s alpha ≥0.997; intraclass correlation coefficient ≥0.987 and an adequate level of
Zimakov, P. V.; Kulichenko, V. V.
1960-07-01
isotopos procedentes de la fision, consiste en encerrarlos en bloques de vidrio fundido. Exponen los principios fisicoquimicos de la transformacion de los desechos liquidos radiactivos en bloques solidos. La memoria contiene termogramas de este proceso y un analisis de sus caracteristicas. Se indican las condiciones de fusion de las masas de vidrio, especialmente las que favorecen el desplazamiento de los aerosoles radiactivos. Se presentan algunos resultados del estudio de la composicion quimica de los isotopos de fision radiactivos en el interior de la masa solida en relacion con la eliminacion de su radiactividad mediante el lavado. Por ultimo, se dan algunos resultados del calculo de las temperturas a que es posible recalentar los bloques radiactivos segun sus caracteristicas. (author) [Russian] Doklad ishodit iz polozhenija, chto nailuchshej formoj zahoronenija oskolochnyh izotopov javljajutsja steklovidnye plavlenye bloki, vkljuchajushhie v svoej strukture jeti oskolki. Izlagajutsja fiziko-himicheskie osnovy prevrashhenija zhidkih radioaktivnyh othodov v tverdye bloki. Privodjatsja termogrammy jetogo processa i analizirujutsja ee otdel'nye osobennosti. Ukazyvajutsja uslovija plavlenija steklovidnoj massy, osobenno sposobstvujushhie poletu radioaktivnyh ajerozolej. Privodjatsja nekotorye rezul'taty izuchenija himicheskogo sostojanija radioaktivnyh oskolkov v tverdoj masse v svjazi s vymyvaniem radioaktivnosti iz nee. V zakljuchenie privodjatsja rezul'taty podscheta temperatur, do kotoryh mogut nagrevat'sja radioaktivnye bloki v zavisimosti ot ih harakteristik. (author)
Phillips, G O; Criddle, W J [Department of Chemistry, University College, Cardiff (United Kingdom)
1962-01-15
chromatogrammes sur bandes de papier; elle n'exige qu'une modification peu couteuse du materiel de comptage traditionnel. (author) [Spanish] Dado que los metodos analiticos clasicos no permiten obtener resultados satisfactorios, los autores han perfeccionado unos metodos de dilucion isotopica para identificar y valorar los productos que se forman en pequenas cantidades al exponer hidratos de carbono en solucion acuosa a las radiaciones gamma del {sup 60}Co. Las autorradiografias de cromatogramas sobre papel, obtenidos despues de irradiar soluciones de azucares marcados con {sup 14}C, revelan una considerable degradacion molecular. Gracias a un metodo de dilucion isotopica inverso basado en la adicion de portadores conocidos, y en la obtencion de derivados cristalizados de los fragmentos, los autores han podido determinar cuantitativamente los siguientes constituyentes. El metodo descrito por los autores permite distinguir entre estereoisomeros y valorar cada lino de ellos por separado. Asimismo puede utilizarse para resolver otros problemas de orden analitico que plantea la quimica de los hidratos de carbono. Los autores describen un nuevo metodo de exploracion y registro de la radiactividad a lo largo de las tiras de papel en las que se ha desarrollado el cromatograma. Este metodo solo requiere una modificacion poco onerosa del equipo de recuento corriente. (author) [Russian] Dlya identifikatsii i otsenki nebol'shikh kolichestv obrazovavshikhsya produktov pri obluchenii karbogidratov v vodnom rastvore gamma-aktivnym kobal'tom-60 byli razrabotany metody razbavleniya izotopov. Obychnye zhe analiticheskie metody okazalis' nedostatochnymi. Po obluchenii rastvorov S14-sakhar podgotovlennye avtoradiografii posle khromatografii na bumage ukazyvayut na znachitel'noe snizhenie. Ispol'zovanie protsedury obratnogo izotopnogo rastvora, svyazannoj s dobavkoj izvestnykh nositelej i preobrazovaniem oskolkov v derivaty kristallov, byli opredeleny kolichestvennye razmery sleduyushchikh
Ultrasonic Histotripsy for Tissue Therapy
Pahk, K. J.; Dhar, D. K.; Malago, M.; Saffari, N.
2015-01-01
Hepatocyte transplantation has been considered and investigated as a promising and alternative method to liver transplantation for treating liver-based metabolic disorder in newborns over the past two decades. Although some clinical trials have been conducted and shown clinical benefits and outcomes, it is difficult to deliver and achieve a desired level of integration and transplantation of hepatocytes in the liver parenchyma. To overcome this problem, this work introduces an alternative method to a portal-infused-hepatocyte cell transplantation. To improve the level of engraftment of transplantable hepatocytes, these are injected directly into cavities generated by ultrasonic histotripsy. Histotripsy is an extracorporeal noninvasive technique which has been recently developed using high intensity focused ultrasound (HIFU) for inducing tissue fractionation with no coagulative necrosis. The exact mechanisms for the tissue fractionation are not well understood yet; but the possible mechanisms are thought to be a combination of nonlinear wave propagation effect, explosive bubble growth and ultrasonic atomization. The main objectives of this work are to demonstrate the feasibility of this new cell therapy and evaluate and distinguish between the different types of cavitation activity for either a thermally or a mechanically induced lesion. In the present work, numerical studies on the bubble dynamics (the Gilmore-Akulichev bubble model coupled with the Khokhlov-Zabolotskaya-Kuznetsov equation) and both ex- and in vivo liver experiments are conducted with histological analysis (haematoxylin and eosin stain). The numerical and the experimental results suggest that (a) the acoustic emissions emitted during the thermal ablation and the histotripsy exposure can be distinguished both numerically and experimentally and (b) the proposed cell therapy may potentially form an effective and safe clinical treatment for replacing and correcting disordered hepatocytes, although the
Classification of homoclinic rogue wave solutions of the nonlinear Schrödinger equation
Osborne, A. R.
2014-01-01
Certain homoclinic solutions of the nonlinear Schrödinger (NLS) equation, with spatially periodic boundary conditions, are the most common unstable wave packets associated with the phenomenon of oceanic rogue waves. Indeed the homoclinic solutions due to Akhmediev, Peregrine and Kuznetsov-Ma are almost exclusively used in scientific and engineering applications. Herein I investigate an infinite number of other homoclinic solutions of NLS and show that they reduce to the above three classical homoclinic solutions for particular spectral values in the periodic inverse scattering transform. Furthermore, I discuss another infinity of solutions to the NLS equation that are not classifiable as homoclinic solutions. These latter are the genus-2N theta function solutions of the NLS equation: they are the most general unstable spectral solutions for periodic boundary conditions. I further describe how the homoclinic solutions of the NLS equation, for N = 1, can be derived directly from the theta functions in a particular limit. The solutions I address herein are actual spectral components in the nonlinear Fourier transform theory for the NLS equation: The periodic inverse scattering transform. The main purpose of this paper is to discuss a broader class of rogue wave packets1 for ship design, as defined in the Extreme Seas program. The spirit of this research came from D. Faulkner (2000) who many years ago suggested that ship design procedures, in order to take rogue waves into account, should progress beyond the use of simple sine waves. 1An overview of other work in the field of rogue waves is given elsewhere: Osborne 2010, 2012 and 2013. See the books by Olagnon and colleagues 2000, 2004 and 2008 for the Brest meetings. The books by Kharif et al. (2008) and Pelinovsky et al. (2010) are excellent references.
[The comprehensive approach to the rehabilitative treatment of junior athletes].
Stepanenko, N P; Levitskaya, T E; Tsekhmeistruk, E A; Tren'kaeva, N A; Tyulyupo, S V; Dostovalova, O V; Kremeno, S V; Shakhova, S S; Chekcheeva, V D
The objective of the present study was the development of the comprehensive program for the medico-psychological follow-up of the male and female junior athletes (rhythmic gymnastics) with the purpose of stabilizing their hormonal and emotional status, as well as improving sport performances based on the use of modern hardware-software technologies. The comprehensive examination of 72 female athletes at the mean age of 11.5±0.6 years attending R. Kuznetsov specialized school of rhythmic gymnastics of the Olympic reserve in the city of Seversk has been undertaken on the basis of Tomsk Research Institute of Balneology and Physiotherapy, the branch of Siberian Federal Research and Clinical Centre. The program of comprehensive medical psychological rehabilitation for the junior athletes of either sex engaged in sportive activities requiring precise technical actions has been elaborated. The method of the combined therapeutic treatment included physical exercises therapy, manual massage, dry carbonic bathtubs, psychological activities with the application of biological feedback trainings and cognitive trainings; it was intended for the correction of the hormonal status and the improvement of the psycho-emotional conditions of the athletes. The combined treatment based on the use of the modern hardware-software technologies was shown to promote the restoration and development of the psychophysical and psychological qualities of the male and female junior athletes indispensable for the maintenance of their high readiness for the efficient sports activities at the subsequent stages of the training cycle. In addition, such treatment enhances the adaptation resources of the athletes.
In search of allosteric modulators of a7-nAChR by solvent density guided virtual screening.
Dey, Raja; Chen, Lin
2011-04-01
Nicotinic acetylcholine receptors (nAChR) are pentameric ligand gated ion channels whose activity can be modulated by endogenous neurotransmitters as well as by synthetic ligands that bind the same or distinct sites from the natural ligand. The subtype of α7 nAChR has been considered as a potenial therapeutic target for Alzheimer's disease, schizophrenia and other neurological and psychiatric disorders. Here we have developed a homology model of α7 nAChR based on two high resolution crystal structures with Brookhaven Protein Data Bank (PDB) codes 2QC1 and 2WN9 for threading on one monomer and then for building a pentamer, respectively. A number of small molecule binding sites are identified using Pocket Finder (J. An, M. Tortov, and R. Abagyan, Molecular & Cellular Proteomics, 4.6, 752-761 (2005)) of Internal Coordinate Mechanics (ICM). Remarkably, these computer-identified sites match perfectly with ordered solvent densities found in the high-resolution crystal structure of α1 nAChR, suggesting that the surface cavities in the α7 nAChR model are likely binding sites of small molecules. A high throughput virtual screening by flexible ligand docking of 5008 small molecule compounds was performed at three potential allosteric modulator (AM) binding sites of α7 nAChR using Molsoft ICM software (R. Abagyan, M. Tortov and D. Kuznetsov, J Comput Chem 15, 488-506, (1994)). Some experimentally verified allosteric modulators of α7 like CCMI comp-6, LY 7082101, 5-HI, TQS, PNU-120596, genistein, and NS-1738 ranked among top 100 compounds, while the rest of the compounds in the list could guide further search for new allosteric modulators.
Ultrasonic Histotripsy for Tissue Therapy
Pahk, K J; Saffari, N; Dhar, D K; Malago, M
2015-01-01
Hepatocyte transplantation has been considered and investigated as a promising and alternative method to liver transplantation for treating liver-based metabolic disorder in newborns over the past two decades. Although some clinical trials have been conducted and shown clinical benefits and outcomes, it is difficult to deliver and achieve a desired level of integration and transplantation of hepatocytes in the liver parenchyma. To overcome this problem, this work introduces an alternative method to a portal-infused-hepatocyte cell transplantation. To improve the level of engraftment of transplantable hepatocytes, these are injected directly into cavities generated by ultrasonic histotripsy. Histotripsy is an extracorporeal noninvasive technique which has been recently developed using high intensity focused ultrasound (HIFU) for inducing tissue fractionation with no coagulative necrosis. The exact mechanisms for the tissue fractionation are not well understood yet; but the possible mechanisms are thought to be a combination of nonlinear wave propagation effect, explosive bubble growth and ultrasonic atomization. The main objectives of this work are to demonstrate the feasibility of this new cell therapy and evaluate and distinguish between the different types of cavitation activity for either a thermally or a mechanically induced lesion. In the present work, numerical studies on the bubble dynamics (the Gilmore-Akulichev bubble model coupled with the Khokhlov-Zabolotskaya-Kuznetsov equation) and both ex- and in vivo liver experiments are conducted with histological analysis (haematoxylin and eosin stain). The numerical and the experimental results suggest that (a) the acoustic emissions emitted during the thermal ablation and the histotripsy exposure can be distinguished both numerically and experimentally and (b) the proposed cell therapy may potentially form an effective and safe clinical treatment for replacing and correcting disordered hepatocytes, although the
Finite difference modelling of the temperature rise in non-linear medical ultrasound fields.
Divall, S A; Humphrey, V F
2000-03-01
Non-linear propagation of ultrasound can lead to increased heat generation in medical diagnostic imaging due to the preferential absorption of harmonics of the original frequency. A numerical model has been developed and tested that is capable of predicting the temperature rise due to a high amplitude ultrasound field. The acoustic field is modelled using a numerical solution to the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, known as the Bergen Code, which is implemented in cylindrical symmetric form. A finite difference representation of the thermal equations is used to calculate the resulting temperature rises. The model allows for the inclusion of a number of layers of tissue with different acoustic and thermal properties and accounts for the effects of non-linear propagation, direct heating by the transducer, thermal diffusion and perfusion in different tissues. The effect of temperature-dependent skin perfusion and variation in background temperature between the skin and deeper layers of the body are included. The model has been tested against analytic solutions for simple configurations and then used to estimate temperature rises in realistic obstetric situations. A pulsed 3 MHz transducer operating with an average acoustic power of 200 mW leads to a maximum steady state temperature rise inside the foetus of 1.25 degrees C compared with a 0.6 degree C rise for the same transmitted power under linear propagation conditions. The largest temperature rise occurs at the skin surface, with the temperature rise at the foetus limited to less than 2 degrees C for the range of conditions considered.
Khater, Mostafa M. A.; Seadawy, Aly R.; Lu, Dianchen
2018-06-01
In this research, we study new two techniques that called the extended simple equation method and the novel (G‧/G) -expansion method. The extended simple equation method depend on the auxiliary equation (dϕ/dξ = α + λϕ + μϕ2) which has three ways for solving depends on the specific condition on the parameters as follow: When (λ = 0) this auxiliary equation reduces to Riccati equation, when (α = 0) this auxiliary equation reduces to Bernoulli equation and when (α ≠ 0, λ ≠ 0, μ ≠ 0) we the general solutions of this auxiliary equation while the novel (G‧/G) -expansion method depends also on similar auxiliary equation (G‧/G)‧ = μ + λ(G‧/G) + (v - 1)(G‧/G) 2 which depend also on the value of (λ2 - 4 (v - 1) μ) and the specific condition on the parameters as follow: When (λ = 0) this auxiliary equation reduces to Riccati equation, when (μ = 0) this auxiliary equation reduces to Bernoulli equation and when (λ2 ≠ 4 (v - 1) μ) we the general solutions of this auxiliary equation. This show how both of these auxiliary equation are special cases of Riccati equation. We apply these methods on two dimensional nonlinear Kadomtsev-Petviashvili Burgers equation in quantum plasma and three-dimensional nonlinear modified Zakharov-Kuznetsov equation of ion-acoustic waves in a magnetized plasma. We obtain the exact traveling wave solutions of these important models and under special condition on the parameters, we get solitary traveling wave solutions. All calculations in this study have been established and verified back with the aid of the Maple package program. The executed method is powerful, effective and straightforward for solving nonlinear partial differential equations to obtain more and new solutions.
III International Conference on Laser and Plasma Researches and Technologies
2017-12-01
A.P. Kuznetsov and S.V. Genisaretskaya III Conference on Plasma and Laser Research and Technologies took place on January 24th until January 27th, 2017 at the National Research Nuclear University "MEPhI" (NRNU MEPhI). The Conference was organized by the Institute for Laser and Plasma Technologies and was supported by the Competitiveness Program of NRNU MEPhI. The conference program consisted of nine sections: • Laser physics and its application • Plasma physics and its application • Laser, plasma and radiation technologies in industry • Physics of extreme light fields • Controlled thermonuclear fusion • Modern problems of theoretical physics • Challenges in physics of solid state, functional materials and nanosystems • Particle accelerators and radiation technologies • Modern trends of quantum metrology. The conference is based on scientific fields as follows: • Laser, plasma and radiation technologies in industry, energetic, medicine; • Photonics, quantum metrology, optical information processing; • New functional materials, metamaterials, “smart” alloys and quantum systems; • Ultrahigh optical fields, high-power lasers, Mega Science facilities; • High-temperature plasma physics, environmentally-friendly energetic based on controlled thermonuclear fusion; • Spectroscopic synchrotron, neutron, laser research methods, quantum mechanical calculation and computer modelling of condensed media and nanostructures. More than 250 specialists took part in the Conference. They represented leading Russian scientific research centers and universities (National Research Centre "Kurchatov Institute", A.M. Prokhorov General Physics Institute, P.N. Lebedev Physical Institute, Troitsk Institute for Innovation and Fusion Research, Joint Institute for Nuclear Research, Moscow Institute of Physics and Tecnology and others) and leading scientific centers and universities from Germany, France, USA, Canada, Japan. We would like to thank heartily all of
Tararykov, A. V.; Garyaev, A. B.
2017-11-01
The possibility of increasing the energy efficiency of production processes by converting the initial fuel - natural gas to synthesized fuel using the heat of the exhaust gases of plants involved in production is considered. Possible applications of this technology are given. A mathematical model of the processes of heat and mass transfer occurring in a thermochemical reactor is developed taking into account the nonequilibrium nature of the course of chemical reactions of fuel conversion. The possibility of using microchannel reaction elements and facilities for methane conversion in order to intensify the process and reduce the overall dimensions of plants is considered. The features of the course of heat and mass transfer processes under flow conditions in microchannel reaction elements are described. Additions have been made to the mathematical model, which makes it possible to use it for microchannel installations. With the help of a mathematical model, distribution of the parameters of mixtures along the length of the reaction element of the reactor-temperature, the concentration of the reacting components, the velocity, and the values of the heat fluxes are obtained. The calculations take into account the change in the thermophysical properties of the mix-ture, the type of the catalytic element, the rate of the reactions, the heat exchange processes by radiation, and the lon-gitudinal heat transfer along the flow of the reacting mixture. The reliability of the results of the application of the mathematical model is confirmed by their comparison with the experimental data obtained by Grasso G., Schaefer G., Schuurman Y., Mirodatos C., Kuznetsov V.V., Vitovsky O.V. on similar installations.
A.V. CHAYANOV ON THE WAY TO THE THEORY OF NON-CAPITALIST ECONOMY
А А Крамар
2018-12-01
Full Text Available Alexander V. Chayanov (1888-1937 is a famous Russian economist, theorist of the organization of economy, a brilliant representative of the generation of the “golden age” of the economic science in Russia. One of the key elements of his scientific legacy is the theory of non-capitalist forms of economy, and one of its aspects - international agrarian studies of the features of the organization of agriculture in different countries. The organizational-production school developed a theory of labor economy and came close to the general theory of non-capitalist forms of economy; however, its studies were inter-rupted by the repressions of the 1920s. The article considers the international studies of A.V. Chayanov to clarify and develop some findings of the today’s scholars (I.A. Kuznetsov, A.M. Nikulin, T.A. Savinova. The author proposes a new interpretation of the organizational-production school as having a dualistic character. The works of Alexander N. Chelintsev (1874-1962, Nicholay P. Makarov (1886-1980 and other colleagues of A.V. Chayanov from the organizational-production school focused on both theoretical issues such as the fundamental laws of functioning and development of agriculture, and practical issues of scientific management of an individual farm and agriculture in general. The author considers the orga-nizational-production school as dualistic: it studies both theory and management of peasant economy at micro- and macro-levels proceeding from the analysis of the individual farm structure to the issues of the optimal production location and optimal management of ‘a mass of peasant farms’. The system approach to the organization of economy, cooperation, zoning and economic policy developed by the organizational-production school is still relevant for the contemporary use.
Investigations of coastal zones using a modular amphibious vehicle
Zeziulin, Denis; Makarov, Vladimir; Filatov, Valery; Beresnev, Pavel; Belyakov, Vladimir; Kurkin, Andrey
2017-04-01
The project aims to develop a means of verification of data on sea excitement derived from Autonomous mobile robotic system (AMRS) for coastal monitoring and forecasting marine natural disasters [Kurkin A., Pelinovsky E., Tyugin D., Giniyatullin A., Kurkina O., Belyakov V., Makarov V., Zeziulin D., Kuznetsov K. Autonomous Robotic System for Coastal Monitoring // Proceedings of the 12th International Conference on the Mediterranean Coastal Environment MEDCOAST. 2015. V. 2. P. 933-944]. The chassis of the developed remote-controlled modular amphibious vehicle (MAV) will be equipped with a video camera and a hydrostatic wave-plotting device with strings sensors mounted on the stationary body's supports. To track the position of the MAV there will be installed the navigation system in order to correct the measurement data. The peculiarity of the tricycle MAV is the ability to change its geometric parameters that will increase its stability to actions of destructive waves and mobility. In May-June 2016 authors took part in conducting field tests of the AMRS on the Gulf of Mordvinov (Sea of Okhotsk, Sakhalin Island). Participation in this expedition contributed to obtaining experimental data on the topography and the physical and mechanical properties of the surf zone of the most promising field of using the MAV as a road for its moving. Within the project there was developed a mathematical model of the MAV motion in coastal conditions taking into account the new analytical dependences describing the physical and mechanical characteristics of the ground surfaces and the landscape, as well as hydrodynamic effects of surf zones. The reasonable selection of rational parameters of the MAV and developing the methodology of creating effective vehicles for investigations of specific coastal areas of the Okhotsk Sea will be made by using the mathematical model.
Kinetics of end-to-end collision in short single-stranded nucleic acids.
Wang, Xiaojuan; Nau, Werner M
2004-01-28
A novel fluorescence-based method, which entails contact quenching of the long-lived fluorescent state of 2,3-diazabicyclo[2.2.2]-oct-2-ene (DBO), was employed to measure the kinetics of end-to-end collision in short single-stranded oligodeoxyribonucleotides of the type 5'-DBO-(X)n-dG with X = dA, dC, dT, or dU and n = 2 or 4. The fluorophore was covalently attached to the 5' end and dG was introduced as an efficient intrinsic quencher at the 3' terminus. The end-to-end collision rates, which can be directly related to the efficiency of intramolecular fluorescence quenching, ranged from 0.1 to 9.0 x 10(6) s(-1). They were strongly dependent on the strand length, the base sequence, as well as the temperature. Oligonucleotides containing dA in the backbone displayed much slower collision rates and significantly higher positive activation energies than strands composed of pyrimidine bases, suggesting a higher intrinsic rigidity of oligoadenylate. Comparison of the measured collision rates in short single-stranded oligodeoxyribonucleotides with the previously reported kinetics of hairpin formation indicates that the intramolecular collision is significantly faster than the nucleation step of hairpin closing. This is consistent with the configurational diffusion model suggested by Ansari et al. (Ansari, A.; Kuznetsov, S. V.; Shen, Y. Proc.Natl. Acad. Sci. USA 2001, 98, 7771-7776), in which the formation of misfolded loops is thought to slow hairpin formation.
Somayeh gharloghi
2017-03-01
Full Text Available Introduction High intensity focused ultrasound (HIFU is considered a noninvasive and effective technique for tumor ablation. Frequency and acoustic power are the most effective parameters for temperature distribution and the extent of tissue damage. The aim of this study was to optimize the operating transducer parameters such as frequency and input power in order to acquire suitable temperature and thermal dose distribution in the course of a numerical assessment. Materials and Methods To model the sound propagation, the Khokhlov-Zabolotskava-Kuznetsov (KZK nonlinear wave equation was used and simulation was carried out using MATLAB HIFU toolbox. Bioheat equation was applied to calculate the transient temperature in the liver tissue. Frequency ranges of 2, 3, 4, and 5 MHz and power levels of 50 and 100 W were applied using an extracorporeal transducer. Results Using a frequency of 2 MHz, the maximum temperatures reached 53°C and 90°C in the focal point for power levels of 50 W and 100 W, respectively. With the same powers and using a frequency of 3 MHz, the temperature reached to 71°C and 170°C, respectively. In addition, for these power levels at the frequency of 4 MHz, the temperature reached to 72°C and 145°C, respectively. However, at the 5 MHz frequency, the temperature in the focal spot was either 57°C or 79°C. Conclusion Use of frequency of 2 MHz and power of 100 W led to higher thermal dose distribution, and subsequently, reduction of the treatment duration and complications at the same exposure time in ablation of large tumors.
Simulations of nonlinear continuous wave pressure fields in FOCUS
Zhao, Xiaofeng; Hamilton, Mark F.; McGough, Robert J.
2017-03-01
The Khokhlov - Zabolotskaya - Kuznetsov (KZK) equation is a parabolic approximation to the Westervelt equation that models the effects of diffraction, attenuation, and nonlinearity. Although the KZK equation is only valid in the far field of the paraxial region for mildly focused or unfocused transducers, the KZK equation is widely applied in medical ultrasound simulations. For a continuous wave input, the KZK equation is effectively modeled by the Bergen Code [J. Berntsen, Numerical Calculations of Finite Amplitude Sound Beams, in M. F. Hamilton and D. T. Blackstock, editors, Frontiers of Nonlinear Acoustics: Proceedings of 12th ISNA, Elsevier, 1990], which is a finite difference model that utilizes operator splitting. Similar C++ routines have been developed for FOCUS, the `Fast Object-Oriented C++ Ultrasound Simulator' (http://www.egr.msu.edu/˜fultras-web) to calculate nonlinear pressure fields generated by axisymmetric flat circular and spherically focused ultrasound transducers. This new routine complements an existing FOCUS program that models nonlinear ultrasound propagation with the angular spectrum approach [P. T. Christopher and K. J. Parker, J. Acoust. Soc. Am. 90, 488-499 (1991)]. Results obtained from these two nonlinear ultrasound simulation approaches are evaluated and compared for continuous wave linear simulations. The simulation results match closely in the farfield of the paraxial region, but the results differ in the nearfield. The nonlinear pressure field generated by a spherically focused transducer with a peak surface pressure of 0.2MPa radiating in a lossy medium with β = 3.5 is simulated, and the computation times are also evaluated. The nonlinear simulation results demonstrate acceptable agreement in the focal zone. These two related nonlinear simulation approaches are now included with FOCUS to enable convenient simulations of nonlinear pressure fields on desktop and laptop computers.
Rabotnov, N. S.; Smirenkin, G. N.; Soldatov, A. C.; Usachev, L. N. [Fiziko-Energeticheskij Institut, Obninsk, SSSR (Russian Federation); Kapica, S. P.; Cipenjuk, I. Ju.M. [Institut Fizicheskih Problem, Moskva, SSSR (Russian Federation)
1965-07-15
la cuestion de la paridad del estado fundamental del MaPu en relacion con los resultados de las mediciones de la distribucion angular de los fragmentos procedentes de la fotofision del {sup 239}Pu, donde se ha observado un cambio del signo de anisotropia, de conformidad con las previsiones teoricas para los canales K = 1 /2 y 3/2. (author) [Russian] Soobshhajutsja rezul'taty izmerenij uglovyh raspredelenij oskolkov pri fotodelenii U{sup 238}, Th{sup 232}, Pu{sup 240} i Pu{sup 239}, vypolnennyh na puchke gamma-kvantov tormoznogo izluchenija. Istochnikom gamma-izluchenija sluzhil mikrotron Instituta fizicheskih problem AN SSSR s moshhnost'ju puchka 12 Mjev. Ispol'zovanie mikrotrona v kachestve moshhnogo istochnika gamma-luchej pozvolilo proizvesti izmerenija uglovyh raspredelenij v naibolee interesnoj i do sih por ne izuchennoj oblasti jenergij gamma-kvantov s E{sub makc} < 6 Mjev. Dlja U{sup 238} issledovanija byli proizvedeny v diapazone jenergij ot 5,2 Mjev do 9,2 Mjev, dlja Th{sup 232} - ot 5,4 Mjev do 6,9 Mjev, dlja Pu{sup 240} - ot 5,4 Mjev do 7,9 Mjev i dlja Pu{sup 239} - ot 5,4 Mjev do 7,9 Mjev. Privodjatsja takzhe rezul'taty izmerenij uglovyh raspredelenij pri fotodjo- lenii U{sup 238} i Th{sup 232} gamma-luchami reakcii F{sup 19} (p, {alpha}{gamma}). Istochnikom gamma-izluchenija javljalas' tolstaja mishen' iz SaEg, obluchavshajasja protonami s jenergiej. 1,45 Mjev. - V rezul'tate jetih izmerenij udalos' ustanovit', v sootvetstvii s bol'shinstvom vypolt nennyh ranee jeksperimentov no v protivopolozhnost' dannym Lazarevoj i dr. i Forkmana i Juhansona, chto vklad delenij, svjazannyh s kvadrupol'nym pogloshheniem fotonov v polnoe sechenie delenija mal v oblasti jenergij E Less-Than-Or-Equal-To 6 MeV. Vpervye pokazano, chto v soglasii s teoreticheskimi predposylkami, osnovannymi na .modeli kanalov delenija O.Bora, otnositel'nyj ves kvadrupol'noj komponenty stanovitsja sushhestvennym tol'ko pri jenergijah vozbuzhdenija nizhe poroga 'dipol'nogo' delenija
';EXPERIMENTING with a Small Planet' as AN Experiment
Hay, W. W.
2013-12-01
-to-nothing about Earth history. The book 'Experimenting with a Small Planet - A Scholarly Entertainment' assumes that the reader knows nothing except how to read. The 900 + pages have over 400 illustrations to break up the text into short self-contained segments. Through informal storytelling it builds up the background necessary to understand our sophisticated science. It introduces mathematics, Newtonian and quantum physics, chemistry, and some basic biology, then goes on to explain how the atmosphere, ocean and climate system work, and how human activies are affecting them. Each of the chapters on science is followed by an ';Intermezzo' of personal stories from my life experiences, covering topics such as being present when the Berlin Wall went up, assisting in the defection of an important scientist from a communist country, becoming a close friend of Nikita Khrushchev's science advisor, and my involvement in scientific ocean drilling since its inception. To my great surprise, the book, intended for the general public, is being used as a college text at both the undergraduate and graduate level - in Europe as well as in the US. The publisher, Springer Verlag, was very cooperative in helping to bring out this innovative approach to science education.
Pamięć o granicach. Demarkacyjna produktywność Wodzic w mijackich wsiach Bituše i Ehloec
Joanna Rękas
2016-10-01
Full Text Available Memory of the borders: The demarcation productivity of Vodici in the Mijaci - inhabited Macedonian villages of Bituše and Ehloec The main aim of this article is to present ways of expressing the inner (religious and external (ethnic social boundaries of Mijaks, as they appear during the celebration of the festival of Epiphany (Revelation of Lord / Baptism of Christ in the Jordan / Vodici in the villages of Bituše and Ehloec (Western Macedonia. The realization of this goal is based on the notion of the demarcation productivity of Vodici, developed based on Nikita Ilyich Tolstoy’s theory of ritual codes, with its semiotic foundations of Yuri Lotman’s signifying elements; insights concerning the relationship between rituals and social boundaries made by Anthony Cohen and Macin Lubaś; Clifford Geertz’s observations on the ritual ignorance of newly-created urban social patterns; the notions of collective memory of religious groups of Maurice Halbwachs; Paul Connerton’s commemorative ceremonies and the concept of media of memory, developed by Jan Assmann, Astrid Erll and others. The sources of analysis are the results of my fieldwork, i.e. participant observation and in-depth interviews (primary sources, 2012–2014, carried out in the mentioned villages, as well as secondary sources: printed materials, manuscripts, as well as audio and video recordings. Pamięć o granicach. Demarkacyjna produktywność Wodzic w mijackich wsiach Bituše i Ehloec Podstawowym celem artykułu jest przedstawienie sposobów ekspresji wewnętrznych (różnowierczych i zewnętrznych (etnicznych granic społecznych Mijaków, ujawniających się podczas obchodów święta Epifanii (Objawienie Pańskie/Chrzest Chrystusa w Jordanie/ Wodzice we wsiach Bituše i Ehloec (zachodnia Macedonia. Realizację tego zamierzenia autorka opiera na demarkacyjnej produktywności Wodzic, wypracowanej w oparciu o teorie: kodów obrzędowych Nikity Ilicza Tołstoja z jej
Dabbs, J. W.T.; Walter, F. J.; Parker, G. W. [Oak Ridge National Laboratory, Oak Ridge, TN (United States)
1965-07-15
mucho mas preciso del numero y naturaleza de los canales de fision disponibles, cuestiones ambas que el fenomeno de la fision suscita desde hace mucho tiempo. En el {sup 235}U se observo, para las resonancias de 1,14 y 8,8 eV, una anisotropfa de los fragmentos de fision proxima al maximo posible, y de signo contrario al de la observada previamente en el caso de los heliones. Asimismo, se comprobo una marcada disminucion de la anisotropia para energias neutronicas proximas a la conocida resonancia de 0,3 eV. Como se carecia de informacion directa sobre los valores J del U se recurrio a un ajuste de niveles multiples a of, analogo al de Kirpichnikov y col., para el que se supuso que J(0,3 eV) Not-Equal-To J(1,14 eV), a diferencia de ajustes anteriores de caracter analogo. Estos datos iniciales son compatibles con una anisotropfa proporcional a la contribucion que se ha calculado aportan a of los dos valores posibles de J. Sin embargo, la forma de la curva no concuerda con otros datos tales como la variacion de la razon cresta a valle de Faler y Tromp; por consiguiente, no deben aceptarse aun como concluyentes los fuertes indicios de que J(0,3 eV) Not-Equal-To J(1,14 eV). Los autores estan efectuando mediciones complementarias para aclarar este concepto. (author) [Russian] Jadra aktinidnyh jelementov urana, neptunija i plutonija mozhno vystroit' v soedinenijah XO{sub 2}Rb(NO{sub 3}){sub 3} putem vzaimodejstvija kvadrupol'nogo momenta jadra s gradientom kristallicheskogo jelektricheskogo polja prosto v rezul'tate ohlazhdenija sootvetstvujushhego edinichnogo kristalla. Vystraivanie jader jetogo tipa sootvetstvuet neravnomernomu uglovomu raspredeleniju osi simmetrii sostavnogo jadra v prostranstve, chto otrazhaet v pervuju ochered' velichinu K. Esli predpolozhit', chto takovo zhe i raspredelenie oskolkov, to poluchim metod dlja ustanovlenija chisla kvantov K v sedlovoj tochke. V Okridzhe byli vypolneny jeksperimenty s vystroennymi jadrami urana-233 i urana{sup -}235 pri
Vandenbosch, R. [University of Washington, Seattle, WA (United States); Unik, J. P.; Huizenga, J. R. [Argonne National Laboratory, Argonne, IL (United States)
1965-07-15
pruebas de que les propiedades del punto de estrangulacion influyen sobre la division final de las masas. El promedio de la energia cinetica total liberada en la fision varia en menos del 0,5% para los distintos canales observados en el punto de estrangulacion. Tambien se ha estudiado la variacion de la energia cinetica total en funcion de la razon masica. (author) [Russian] Delenie slozhnogo jadra urana-235 pri priblizhenii k porogu ego delenija izuchalos' pri pomoshhi reakcii (d, pf) urana-234. V celjah odnovremennoj registracii dlja kazhdogo sovpadajushhego sobytija dvuh kineticheskih jenergij oskolkov delenija i jenergij protona byl ispol'zovan trehparametrovyj analizator. Jenergija vozbuzhdenija, pri kotoroj proishodit delenie, opredeljaetsja kineticheskoj jenergiej sryva protona. Izmenenie uglovoj anizotropii v zavisimosti ot jenergii vozbuzhdenija ukazyvaet na znachitel'no bol'shuju zavisimost' ot struktury, chem jeto bylo polucheno Lamfirom dlja togo zhe jadra v rezul'tate bombardirovki urana-234 bystrymi nejtronami. V sedlovine nabljudalos' po men'shej mere vosem' kanalov delenija dlja intervala jenergii mezhdu porogom i 2 Mjev svyshe poroga. Dlja bolee znachitel'nyh deformacij, bolee tochno opisyvajushhih konfiguraciju sedloviny, oyli prodelany raschety tipa nilssona dlja jenergii odinochnoj chasticy dlja deformirovannogo jadra. Sostojanija odinochnoj chasticy, vyjavlennye Lamfirom, sovmestimy s podschitannymi sostojanijami, priolizhajushhimisja k poverhnosti Fermi dlja ogranichennyh deformacij sedloviny. Glavnoj prichinoj dlja provedenija jetogo jeksperimenta bylo stremlenie izyskat' vozmozhnuju korreljaciju mezhdu asimmetriej massy i uglovoj anizotropiej. Vyhody massy, poluchennye' iz korrelirovannyh jenergij oskolkov, ne ukazyvajut na izmenenie anizotropii v zavisimosti ot massovogo sootnoshenija v protivopolozhnost' jeksperimentam, v kotoryh jenergija vozbuzhdenija, pri kotoroj proishodit delenie, ne javljaetsja postojannoj, i pri kotoroj nabljudalas
Forte, M; Konsta, A; Maranzana, C [European Atomic Energy Community, CCR, ISPRA (Italy)
1962-04-15
hasta impulsos debiles, de unas cuantas decenas de fotoelectrones, y la discriminacion de fragmentos emitidos por captura neutronica en liquidos conteniendo boro. Algunas de estas redes fueron capaces de operar con impulsos de la misma polaridad emitidos por dos de los ultimos dinodos, incluso con la salida de un solo electrodo. Ello puede ser util cuando conviene emplear el anodo independientemente, por ejemplo, para sincronizacion. (author) [Russian] Kak uzhe soobshchalos' ran'she, forma stsintillyatsionnogo impul'sa, kharakterizuyushchaya tip vozbuzhdayushchej chastitsy (ehlektron, proton, al'fa i t.d.), mozhet byt' prevrashchena v nezavisimyj ot amplitudy impul'sa parametr. EHto pozvolyaet vyyavit' posredstvom mnogokanal'nogo analizatora sostav vozbuzhdayushchego stsintillyator puchka so smeshannymi chastitsami. EHtot metod byl uspeshno primenen k neskol'kim stsintillyatoram kak organicheskogo, tak i neorganicheskogo tipa. Privodyatsya detali ehlektronnykh metodik, ispol'zovannykh dlya preobrazovaniya formy impul'sov. Dlya bolee prostykh sluchaev diskriminatsii tol'ko mezhdu dvumya vidami impul'sov (naprimer, diskriminatsiya nejtronov ot gamma-izluchenij) rassmatrivalas' takzhe vozmozhnost' ispol'zovaniya passivnykh skhem, predstavlyayushchikhsya perspektivnymi dlya dal'nejshikh usovershenstvovanij i uproshchenij. Bylo isprobovano neskol'ko skhem, glavnym rezul'tatom chego bylo to, chto pri nalichii fona gamma-izlucheniya udalos' rasprostranit' diskriminatsiyu protonov otdachi v zhidkikh stsintillyatorakh na malye impul'sy vsego lish' v neskol'ko desyatkov fotoehlektronov, a takzhe dobit'sya diskriminatsii oskolkov zakhvata nejtronov v soderzhashchikh bor zhidkostyakh. Nekotorye iz ehtikh skhem byli prednaznacheny dlya raboty s impul'sami odinakovoj polyarnosti, podavaemymi dvumya poslednimi ehlektrodami umnozhitelya, ili dazhe s vykhodnymi impul'sami odnogo lish' ehlektroda. EHto mozhet okazat'sya poleznym pri nezavisimom ispol'zovanii anoda, naprimer, dlya
Evidence-based gene models for structural and functional annotations of the oil palm genome.
Chan, Kuang-Lim; Tatarinova, Tatiana V; Rosli, Rozana; Amiruddin, Nadzirah; Azizi, Norazah; Halim, Mohd Amin Ab; Sanusi, Nik Shazana Nik Mohd; Jayanthi, Nagappan; Ponomarenko, Petr; Triska, Martin; Solovyev, Victor; Firdaus-Raih, Mohd; Sambanthamurthi, Ravigadevi; Murphy, Denis; Low, Eng-Ti Leslie
2017-09-08
biosynthesis and disease resistance. The study demonstrated the advantages of having an integrated approach to gene prediction and developed a computational framework for combining multiple genome annotations. These results, available in the oil palm annotation database ( http://palmxplore.mpob.gov.my ), will provide important resources for studies on the genomes of oil palm and related crops. This article was reviewed by Alexander Kel, Igor Rogozin, and Vladimir A. Kuznetsov.
В. В. Голіна
2015-11-01
Full Text Available Problem setting. Crime is one of the oldest existing forms of social life, despite the burning desire of human to destroy it. World history persuades explicitly that cruel, inhumane punishment punishments are inefficient to prevent crime. It’s necessary to rebuild human behavior, and this is possible through the elimination of various stimuli that enhance human passions and lead to irrational, destructive behavior. Recent research and publications analysis. Theory of combating crime primarily through its prevention has been substantively enriched during XIX-XXI centuries through scientific works of domestic and foreign criminologists and other researchers, which laid the philosophical, sociological, moral, psychological, social, anthropological, organizational, managerial, economic, educational, penitentiary and other types of crime prevention (Yu. M. Antonyan, A. Herry, A. Quetelet, C. Lombroso, D. Drill, E. Durkheim, G. Tarde, E. Ferry, R. Garofalo, A. Kystyakivskyi, M. Gernet, A. Gertsenzon, E. Sutherland, N. Kuznetsov, V. Kudryavtsev, A. Sakharov, I. Karpets, A. Zelinsky, V. Dryomin, O. Tulyakov, O. Litvinov, A. Zakalyuk, V. Shakun, B. Golovkin etc.. Paper objective is providing a thorough analysis of a range of issues, related to the criminological crime prevention as an essential part of special criminological crime prevention. Paper main body. Crime is a complex social phenomenon whose causes and conditions are usually associated with a genetic predisposition to decline form normal behavior, along with the defects and imperfections of the society. Crime prevention is state social policy aimed at overcoming dangerous criminal contradictions in social relations in order to reach positive resolution and the gradual elimination (so-called general social prevention along with proactive practice of combating criminal offenses at various stages. Crime prevention can be divided into several types: prevention in advance, restrictive prevention
Hernandez, David; Sanchez, Miguel Angel; Medina, Pablo
2010-05-01
A laboratory experimental set - up for studying the behaviour of sediment in presence of a turbulent field with zero mean flow is compared with the behaviour of turbidity currents [1] . Particular interest is shown on the initiation of sediment motion and in the sediment lift - off. The behaviour of the turbidity current in a flat ground is compared with the zero mean flow oscilating grid generated turbulence as when wave flow lifts off suspended sediments [2,3]. Some examples of the results obtained with this set-up relating the height of the head of the turbidity current to the equilibrium level of stirred lutoclines are shown. A turbulent velocity u' lower than that estimated by the Shield diagram is required to start sediment motion. The minimum u' required to start sediment lift - off, is a function of sediment size, cohesivity and resting time. The lutocline height depends on u', and the vorticity at the lutocline seems constant for a fixed sediment size [1,3]. Combining grid stirring and turbidty current head shapes analyzed by means of advanced image analysis, sediment vertical fluxes and settling speeds can be measured [4,5]. [1] D. Hernandez Turbulent structure of turbidity currents and sediment transport Ms Thesis ETSECCPB, UPC. Barcelona 2009. [2] A. Sánchez-Arcilla; A. Rodríguez; J.C. Santás; J.M. Redondo; V. Gracia; R. K'Osyan; S. Kuznetsov; C. Mösso. Delta'96 Surf-zone and nearshore measurements at the Ebro Delta. A: International Conference on Coastal Research through large Scale Experiments (Coastal Dynamics '97). University of Plymouth, 1997, p. 186-187. [3] P. Medina, M. A. Sánchez and J. M. Redondo. Grid stirred turbulence: applications to the initiation of sediment motion and lift-off studies Physics and Chemistry of the Earth, Part B: Hydrology, Oceans and Atmosphere. 26, Issue 4, 2001, Pages 299-304 [4] M.O. Bezerra, M. Diez, C. Medeiros, A. Rodriguez, E. Bahia., A. Sanchez-Arcilla and J.M. Redondo. Study on the influence of waves on
Ultrastructure of pea and cress root statocytes exposed to high gradient magnetic field
Belyavskaya, N. A.; Chernishov, V. I.; Polishchuk, O. V.; Kondrachuk, A. V.
As it was demonstrated by Kuznetsov & Hasenstein (1996) the high gradient magnetic field (HGMF) can produce a ponderomotive force that results in displacements of amyloplasts and causes the root response similar to the graviresponse. It was suggested that the HGMF could allow to imitate the effects of gravity in microgravity and/or change them in laboratory conditions correspondingly, as well as to study statolith-related processes in graviperception. Therefore, the correlation between the direction of the ponderomotive force resulting in statolith displacements and the direction of the HGMF-induced plant curvature can be the serious argument to support this suggestion and needs the detailed ultrastructural analysis. Seeds of dicotyledon Pisum sativum L. cv. Damir-2 and monocotyledon Lepidium sativum L. cv. P896 were soaked and grown in a vertical position on moist filter paper in chambers at room temperature. Tips of primary roots of vertical control, gravistimulated and exposed to HGMF seedlings were fixed for electron microscopy using conventional techniques. At ultrastructural level, we observed no significant changes in the volume of the individual statocytes or amyloplasts, relative volumes of cellular organelles (except vacuoles), number of amyloplasts per statocyte or surface area of endoplasmic reticulum. No consistent contacts between amyloplasts and any cellular structures, including plasma membrane, were revealed at any stage of magneto- and gravistimulation. By 5 min after onset of magnetostimulation, amyloplasts were located along cell wall distant from magnets. In HGMF, the locations of amyloplasts in columella cells were similar to those in horizontally-oriented roots up to 1 h stimulation. In the latter case, there were sometimes cytoplasmic spherical bodies with a dense vesicle-rich cytoplasm in pea statocytes, which were absent in seedlings exposed to HGMF. In cress root statocytes, both gravi- and magnetostimulation were found to cause the
Kim, Yeonho; Nabili, Marjan; Acharya, Priyanka; Lopez, Asis; Myers, Matthew R
2017-01-01
Safety analyses of transcranial therapeutic ultrasound procedures require knowledge of the dependence of the rupture probability and rupture time upon sonication parameters. As previous vessel-rupture studies have concentrated on a specific set of exposure conditions, there is a need for more comprehensive parametric studies. Probability of rupture and rupture times were measured by exposing the large blood vessel of a live earthworm to high-intensity focused ultrasound pulse trains of various characteristics. Pressures generated by the ultrasound transducers were estimated through numerical solutions to the KZK (Khokhlov-Zabolotskaya-Kuznetsov) equation. Three ultrasound frequencies (1.1, 2.5, and 3.3 MHz) were considered, as were three pulse repetition frequencies (1, 3, and 10 Hz), and two duty factors (0.0001, 0.001). The pressures produced ranged from 4 to 18 MPa. Exposures of up to 10 min in duration were employed. Trials were repeated an average of 11 times. No trends as a function of pulse repetition rate were identifiable, for either probability of rupture or rupture time. Rupture time was found to be a strong function of duty factor at the lower pressures; at 1.1 MHz the rupture time was an order of magnitude lower for the 0.001 duty factor than the 0.0001. At moderate pressures, the difference between the duty factors was less, and there was essentially no difference between duty factors at the highest pressure. Probability of rupture was not found to be a strong function of duty factor. Rupture thresholds were about 4 MPa for the 1.1 MHz frequency, 7 MPa at 3.3 MHz, and 11 MPa for the 2.5 MHz, though the pressure value at 2.5 MHz frequency will likely be reduced when steep-angle corrections are accounted for in the KZK model used to estimate pressures. Mechanical index provided a better collapse of the data (less separation of the curves pertaining to the different frequencies) than peak negative pressure, for both probability of rupture and
Williams, J. [Atomic Energy Research Establishment, Harwell (United Kingdom)
1963-11-15
incorporarlas en matrices de elevada densidad. Los trabajos sobre metodos de elaboracion en escala experimental se hallan bastante avanzados. (author) [Russian] Daetsya obzor vozmozhnosti primeneniya dispersij PuO{sub 2},UO{sub 2}, ThO{sub 2} v matritsakh iz BeO, Al{sub 2}O{sub 3}, MgO i SiO{sub 2} s tochki zreniya sokhraneniya tselostnosti takogo topliva i sposobov ego izgotovleniya. Neizmennost' razmerov i sposobnost' uderzhaniya produktov deleniya yavlyayutsya naibolee vazhnymi svojstvami s tochki zreniya sokhraneniya tselostnosti topliva. Sovmestimost' sostavnykh ehlementov topliva drug s drugom i s teplonositelem okazyvayut vliyanie na neizmennost' razmerov, no v ehtom otnoshenii okislovye vidy topliva obladayut znachitel'nymi preimushchestvami. Na izmenenie razmerov pod dejstviem oblucheniya okazyvayut vliyanie: povrezhdeniya matritsy pod dejstviem nejtronov i oskolkov deleniya; radiatsionnoe povrezhdenie fazy delyashchikhsya veshchestv vosproizvodyashchikh materialov i nakoplenie produktov deleniya v gazoobraznom sostoyanii. Termicheskie napryazheniya takzhe mogut vyzyvat' izmeneniya formy. Odnako svedeniya o mekhanizme relaksatsii napryazhenij slishkom ogranicheny, chtoby mozhno bylo dat' kakuyu-libo priemlimuyu teoreticheskuyu otsenku povedeniyu topliva. Issledovaniya vykhoda produktov deleniya kak v sluchae legkogo oblucheniya, tak i pri sil'nom vygoranii okisej delyashchikhsya veshchestv/vosproizvodyashchikh materialov ogranichivalis' glavnym obrazom gazoobraznymi produktami deleniya, preimushchestvenno ksenonom. Dannye o vykhode drugikh produktov deleniya, a takzhe svedeniya o prokhozhdenii produktov deleniya voobshche cherez vozmozhnye materialy dlya matrits ochen' ogranicheny. Issledovaniya pronitsaemosti chistykh spekshikhsya okisej pokazyvayut, chto dlya ustraneniya otkrytoj poristosti takikh matrits potrebovalos' by dostizhenie plotnostej, dokhodyashchikh po men'shej mere do 95, a to i do 98% ot teoreticheski osushchestvimoj. Dlya izgotovleniya chastits
Genomes to Life Project Quartely Report October 2004.
Heffelfinger, Grant S.; Martino, Anthony; Rintoul, Mark Daniel; Geist, Al; Gorin, Andrey; Xu, Ying; Palenik, Brian
2005-02-01
.genomes-to-life.org Acknowledgment We want to gratefully acknowledge the contributions of the GTL Project Team as follows: Grant S. Heffelfinger1*, Anthony Martino2, Andrey Gorin3, Ying Xu10,3, Mark D. Rintoul1, Al Geist3, Matthew Ennis1, Hashimi Al-Hashimi8, Nikita Arnold3, Andrei Borziak3, Bianca Brahamsha6, Andrea Belgrano12, Praveen Chandramohan3, Xin Chen9, Pan Chongle3, Paul Crozier1, PguongAn Dam10, George S. Davidson1, Robert Day3, Jean Loup Faulon2, Damian Gessler12, Arlene Gonzalez2, David Haaland1, William Hart1, Victor Havin3, Tao Jiang9, Howland Jones1, David Jung3, Ramya Krishnamurthy3, Yooli Light2, Shawn Martin1, Rajesh Munavalli3, Vijaya Natarajan3, Victor Olman10, Frank Olken4, Brian Palenik6, Byung Park3, Steven Plimpton1, Diana Roe2, Nagiza Samatova3, Arie Shoshani4, Michael Sinclair1, Alex Slepoy1, Shawn Stevens8, Chris Stork1, Charlie Strauss5, Zhengchang Su10, Edward Thomas1, Jerilyn A. Timlin1, Xiufeng Wan11, HongWei Wu10, Dong Xu11, Gong-Xin Yu3, Grover Yip8, Zhaoduo Zhang2, Erik Zuiderweg8 *Author to whom correspondence should be addressed (gsheffe%40sandia.gov) 1. Sandia National Laboratories, Albuquerque, NM 2. Sandia National Laboratories, Livermore, CA 3. Oak Ridge National Laboratory, Oak Ridge, TN 4. Lawrence Berkeley National Laboratory, Berkeley, CA 5. Los Alamos National Laboratory, Los Alamos, NM 6. University of California, San Diego 7. University of Illinois, Urbana/Champaign 8. University of Michigan, Ann Arbor 9. University of California, Riverside 10. University of Georgia, Athens 11. University of Missouri, Columbia 12. National Center for Genome Resources, Santa Fe, NM Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.
Permana, Sidik [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology 2-12-1-N1-17, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Nuclear and Biophysics Research Group, Department of Physics, Bandung Institute of Technology, Gedung Fisika, Jl. Ganesha 10, Bandung 40132 (Indonesia); Suud, Zaki [Nuclear and Biophysics Research Group, Department of Physics, Bandung Institute of Technology, Gedung Fisika, Jl. Ganesha 10, Bandung 40132 (Indonesia); Suzuki, Mitsutoshi [Japan Atomic Energy Agency, Nuclear Non-proliferation Science and Technology Center, 2-4 Shirane Shirakata, Tokai-mura, Ibaraki, 319-1195 (Japan)
2009-06-15
Scientific approaches are performed by adopting some methodologies in order to increase a material 'barrier' in plutonium isotope composition by increasing the even mass number of plutonium isotope such as Pu-238, Pu-240 and Pu-242. Higher difficulties (barrier) or more complex requirement for peaceful use of nuclear materials, material fabrication and handling and isotopic enrichment can be achieved by a higher isotopic barrier. Higher barrier which related to intrinsic properties of plutonium isotopes with even mass number (Pu-238, Pu-240 and Pu-242), in regard to their intense decay heat (DH) and high spontaneous fission neutron (SFN) rates were used as a parameter for improving the proliferation resistance of plutonium itself. Pu-238 has relatively high intrinsic characteristics of DH (567 W/kg) and SFN rate of 2660 n/g/s can be used for making a plutonium characteristics analysis. Similar characteristics with Pu-238, other even mass number of plutonium isotopes such as Pu-240 and Pu-242 have been shown in regard to SFN values. Those even number mass of plutonium isotope contribute to some criteria of plutonium characterization which will be adopted for present study such as IAEA, Pellaud and Kessler criteria (IAEA, 1972; Pellaud, 2002; and Kessler, 2004). The study intends to evaluate the trans-uranium doping effect for increasing protected plutonium proliferation in long-life small reactors. The development of small and medium reactor (SMR) is one of the options which have been adopted by IAEA as future utilization of nuclear energy especially for less developed countries (Kuznetsov, 2008). The preferable feature for small reactors (SMR) is long life operation time without on-site refueling and in the same time, it includes high proliferation resistance feature. The reactor uses MOX fuel as driver fuel for two different core types (inner and outer core) with blanket fuel arrangement. Several trans-uranium doping and some doping rates are evaluated
Three-dimensional freak waves and higher-order wave-wave resonances
Badulin, S. I.; Ivonin, D. V.; Dulov, V. A.
2012-04-01
period October 14 - November 6, 2009 almost continuously. Antenna of 6 resistance wave gauges (a pentagon with one center gauge) is used to gain information on wave directions. Wave conditions vary from perfect still to storms with significant wave heights up to Hs = 1.7 meters and wind speeds 15m/s. Measurements with frequency 10Hz for dominant frequencies 0.1 - 0.2Hz fixed 40 freak wave events (criterium H/Hs > 2) and showed no dependence on Hs definitely. Data processing within frequency quasi-spectra approach and directional spectra reconstructions found pronounced features of essentially three-dimensional anomalous waves. All the events are associated with dramatic widening of instant frequency spectra in the range fp - f5w and stronger directional spreading. On the contrary, the classic Benjamin-Feir modulations show no definite links with the events and can be likely treated as dynamically neutral part of wave field. The apparent contradiction with the recent study (Saprykina, Dulov, Kuznetsov, Smolov, 2010) based on the same data collection can be explained partially by features of data processing. Physical roots of the inconsistency should be detailed in further studies. The work was supported by the Russian government contract 11.G34.31.0035 (signed 25 November 2010), Russian Foundation for Basic Research grant 11-05-01114-a, Ukrainian State Agency of Science, Innovations and Information under Contract M/412-2011 and ONR grant N000141010991. Authors gratefully acknowledge continuing support of these foundations.
Harteck, P; Dondes, S [Rensselaer Polytechnic Institute, Troy, NY (United States)
1960-07-15
fision liberada en las fibras de vidrio y de la resistencia termica del circuito. Otro circuito, que habra de funcionar a 50 - 75 atmosferas y 600{sup o}C se encuentra en curso de construccion. Estos circuitos permitiran evaluar las caracteristicas de un sistema continuo, incluido el comportamient o de los productos de fision liberados en la corriente gaseosa. Los autores distinguen tres fases en la cinetica compleja de la oxidacion del nitrogeno: reacciones iniciales en el sistema;, reacciones subsiguientes a la fijacion de cierta cantidad de nitrogeno y, por ultimo, cinetica del equilibrio alcanzado en presencia de radiaciones. Se estudian las condiciones necesarias para la formacion de N{sub 2}0{sub 5}, N{sub 2}0{sub 4} y O{sub 3}, asi como los efectos que ejercen sobre el proceso en conjunto. (author) [Russian] Pri issledovaniyakh okisleniya azota izlucheniem iz reaktorov, kotorye proizvodilis ' v Rensselerovskom institute i v Brukkhejvenskoj natsional'noj laboratorii v techenie ryada let, byla ispol'zovana, v kachestve neposredstvennogo ioniziruyushchego izlucheniya, ehnergiya otdachi oskolkov deleniya putem rasseyaniya urana-235 v steklyannom volokne diametrom priblizitel'no v 5 mikronov. Bylo opredeleno vliyanie temperatury, davleniya i sootnosheniya mezhdu kolichestvom azota i kolichestvom kisloroda na velichinu radiatsionno-khimicheskogo vykhoda G na okislenie azota i rezul'taty byli soobshcheny v tekhnicheskoj literature. Nizhe daetsya kratkaya svodka ehtoj raboty. Upomyanutaya vyshe rabota proizvodilas' nad staticheskimi sistemami ; nedavno proizvedennaya rabota okhvatyvala kak staticheskie, tak i tsiklicheskie sistemy. V staticheskikh sistemakh glavnoe vnimanie obrashchalos' na vliyanie intensivnosti izlucheniya, v osobennosti v sostoyanii kineticheskogo ravnovesiya izlucheniya. Bylo ustanovleno, chto obrazovanie N0{sub 2}. i N{sub 2}0 V smesyakh azota i kisloroda v proportsiyakh 4:1 i 2: 1 proiskhodit do polnogo istoshcheniya yusloroda. TSiklicheskaya
Zimakov, P. V.; Kulichenko, V. V.; Duhovich, F. S.; Salamatmn, B. A.
1963-02-15
mismos y, por consiguiente, en su capacidad de fijacion de los isotopos. Esas alteraciones son mas pronunciadas en la superficie, debido al contacto con los agentes externos (aire, agua). El riesgo-de lixiviacion aumenta, como es logico, con la irradiacion de los bloques. Los experimentos realizados por los autores demuestran que los radioisotopos de las capas superficiales acusan una fuerte tendencia a pasar al estado gaseoso. Teniendo en cuenta el efecto combinado de los factores que actuan sobre los bloques vitreos diurante un almacenamiento prolongado, es preciso, mediante una eleccion adecuada de su composicion quimica (tundente) y de. las condiciones de elaboracion, asegurar la fijacion deseada de los isotopos radiactivos en los bloques enterrados. Ofrece gran interes, en ese sentido, el empleo de compuestos de titanio para la preparacion del fundente. (author) [Russian] V svjazi s tem, chto nekotorye izotopy imejut bol'shie periody poluraspada, neobhodimo obespechit' ih nadezhnuju lokalizaciju ka dlitel'noe vremja, a jeto trebuet izuchenija povedenija takih izotopov v steklovidnyh blokah pod vlijaniem uslovij, kotorye sozdajutsja pri dlitel'nom hranenii: samorazogrev, samoobluchenie, vlijanie okruzhajushhej sredy. Stremlenie ogranichit ob'em blokov d. ja zahoronenija i letuchest' izotopov pri ih prigotovlenii (temperatura - ne vyshe 1200 Degree-Sign C) privodit k neodnorodnoj'strukture takih blokov- Oni javljajutsja ne istinnym steklom, a ''steklovidnymi'' soedinenijami. Svojstva takih blokov i prochnost' lokalizacii v nih oskolochnyh izotopov sil'no zavisjat ot ih himicheskogo sostava (kolichestvo i priroda fljusa), uslovij prigotovlenija i posledujushhego hranenija. Povyshennaja temperatura, razvivajushhajasja v rezul'tate teplovydelenija vysokoradioaktivnyh blokov v mogil'nike, vyzyvaet himicheskie i fizicheskie processy v ih strukturah i sil'no vlijaet na prochnost' lokalizacii v nih oskolkov, osobenno s poverhnosti blokov. Vyshhelachivaemoet' izotopov iz
Merz, E.; Riedel, H. J. [Kernforschungsanlage, Juelich, Federal Republic of Germany (Germany)
1965-04-15
samyh himicheskih soedinenij kak te, kotorye nabljudalis' v jadernyh reakcijah. Odnako dlja{beta}{sup -}-perehoda tipichno znachitel'noe uvelichenie doli mechenyh ishodnyh molekul (uderzhanija). Jeti rezul'taty obsuzhdajutsja na osnovanii teoreticheskih soobrazhenij otnositel'no kolichestva kineticheskoj jenergii, soobshhennoj jadernoj otdachej uchastvujushhim v reakcii molekulam, i otnositel'no vyzyvaemogo vozbuzhdenija. Vydvigaetsja predpolozhenie, chto vid i kolichestvo nekotoryh novyh radioaktivnyh raznovidnostej, obrazujushhihsja v svjazi s jadernymi prevrashhenijami, zavisjat v men'shej mere ot haraktera i koncentracii pervichnyh oskolkov otdachi, chem ot ionov, radikalov i defektov reshetki, vyzvannyh v obluchennom materiale vtorichnymi vozdejstvijami otdachi (uprugimi i neuprugimi vzaimodejstvijami), a takzhe ot osobogo vlijanija kisloroda. (author)
2nd International Open and Distance Learning (IODL Symposium
Reviewed by Murat BARKAN
2006-10-01
directed interactive exercises using flashmx in his workshop. Jack Koumi from UK, presented a workshop about what to teach on video and when to choose other media. He exemplified 27 added value techniques and teaching functions for TV and video. He later specified different capabilities and limitations of eight different media used in teaching, emphasizing the importance of optimizing media deployment. Dr. Janet Bohren from University of Cincinnati and Jennifer McVay-Dyche from United Theological Seminary, explained their experience with a course management system used to develop dialogue between K-12 teachers in Turkey and the US, on the topics of religion, culture and schools. Their workshop provided an overview of a pilot study. They showed us a good case-study of utilizing “Blackboard” as a mean for getting rid of biases and improving the understanding of the American and Turkish teachers against each other. We had very remarkable key notes as well. Dr Nikitas Kastis representing European Distance and E-Learning Network (EDEN made his speech on distance and e-Learning evolutions and trends in Europe. He informed the audience about the application and assessment criteria at European scale, concerning e-Learning in the education and training systems. Meanwhile, our key note speakers took our attention to different applications of virtual learning. Dr. Piet Kommers from University of Twente exemplified a virtual training environment for acquiring surgical skills. Dr. Timothy Shih from Tamkang University presented their project called Hard SCORM (Sharable Content Object Reference Model as an asynchronous distance learning specification. In his speech titled “Engaging and Supporting Problem Solving Online” Prof. David Jonassen from University of Missouri, reflected his vision of the future of education and explained why it should embrace problem solving. Then he showed us examples of incorporating this vision with learning environments for making online problem
13th International Conference on Films and Coatings
2017-01-01
Analytical Review of the Reports Presented at the 13th International Conference on Films and Coatings (ICFC13) V G Kuznetsov 1 and D K Kostrin 2 1 Institute of Problems of Mechanical Engineering, Russian Academy of Sciences, 199178, Saint Petersburg, Russia 2 Saint Petersburg Electrotechnical University “LETI”, 197376, Saint Petersburg, Russia E-mail: kvgipme@gmail.com Abstract. In this preface main trends in the development of films and coatings technology presented at the 13th International Conference on Films and Coatings (ICFC13) that was held on 18–20 April 2017 in Saint Petersburg, Russia are discussed. During the Conference were presented the results of theoretical and experimental research in the physics and mechanics of condensed matter, physics of low temperature plasma, formation of films and coatings using plasma and related methods that were obtained over the past two years that have passed since the previous meeting. Special attention was paid to the study of properties of surfaces and coatings, methods of their research, new coating materials, including nanomaterials, new areas of their application, development of modern equipment and technological processes, surface preparation and many other issues. During the Conference were presented more than 150 reports that were distributed in 8 sections: • vacuum ion-plasma methods; • thermal spray coating methods; • physical processes at all stages of coatings formation; • equipment for application of films and coatings; • materials for sputtering and deposition; • nanomaterials and nanotechnologies; • properties of coatings and films and methods of their evaluation; • preparation of surfaces before application and methods of post-processing of coatings and films. For the first time the Conference had a special section for young scientists, where presentations were made by students, postgraduates, candidates and doctors of science aged up to 35 years. Among the participants were