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Izmir, Turkey

İzmir University is a university in Üçkuyular, İzmir, Turkey, established in 2007 by the Doğanata Education and Culture Foundation, which opened in 2008. Wikipedia.

Hasanov A.,Izmir University
International Journal of Non-Linear Mechanics | Year: 2011

Three classes of inverse coefficient problems arising in engineering mechanics and computational material science are considered. Mathematical models of all considered problems are proposed within the J2-deformation theory of plasticity. The first class is related to the determination of unknown elastoplastic properties of a beam from a limited number of torsional experiments. The inverse problem here consists of identifying the unknown coefficient g(2) (plasticity function) in the non-linear differential equation of torsional creep -(g(∇u2)ux1) x1-(g(∇u2)ux2)x2=2φ, x∈Ω⊂R2, from the torque (or torsional rigidity) T(φ), given experimentally. The second class of inverse problems is related to the identification of elastoplastic properties of a 3D body from spherical indentation tests. In this case one needs to determine unknown Lame coefficients in the system of PDEs of non-linear elasticity, from the measured spherical indentation loading curve P=P(α), obtained during the quasi-static indentation test. In the third model an inverse problem of identifying the unknown coefficient g(2(u)) in the non-linear bending equation is analyzed. The boundary measured data here is assumed to be the deflections wi[τk]:=w(λi;τk), measured during the quasi-static bending process, given by the parameter τk, k=1,K, at some points λi=(x1(i),x2(i)), i=1,M of a plate. An existence of weak solutions of all direct problems are derived in appropriate Sobolev spaces, by using monotone potential operator theory. Then monotone iteration schemes for all the linearized direct problems are proposed. Strong convergence of solutions of the linearized problems, as well as rates of convergence is proved. Based on obtained continuity property of the direct problem solution with respect to coefficients, and compactness of the set of admissible coefficients, an existence of quasi-solutions of all considered inverse problems is proved. Some numerical results, useful from the points of view of engineering mechanics and computational material science, are demonstrated. © 2011 Elsevier Ltd. All rights reserved. Source

Hasanov A.,Izmir University
International Journal of Heat and Mass Transfer | Year: 2012

Inverse problems of identifying the unknown spacewise and time dependent heat sources F(x) and H(t) of the variable coefficient heat conduction equation u t = (k(x)u x) x + F(x)H(t) from supplementary temperature measurement (u T(x)u(x, T f)) at a given single instant of time T f > 0, are investigated. For both inverse source problems, defined to be as ISPF and ISPH respectively, explicit formulas for the Fréchet gradients of corresponding cost functionals are derived. Fourier analysis of these problems shows that although ISPF has a unique solution, ISPH may not have a unique solution. The conjugate gradient method (CGM) with the explicit gradient formula for the cost functional J 1(F) is then applied for numerical solution of ISPF. New collocation algorithm, based on the piecewise linear approximation of the unknown source H(t), is proposed for the numerical solution of the integral equation corresponding to ISPH. The proposed two numerical algorithms are examined through numerical examples for reconstruction of continuous and discontinuous heat sources F(x) and H(t). Computational results, with noise free and noisy data, show efficiency and high accuracy of the proposed algorithms. © 2011 Elsevier Ltd. All rights reserved. Source

This article presents an analytical approach for identification problems related to ion transport problems. In the first part of the study, relationship between the flux ΦL:= (D(x)ux(0,t)x=0 and the current response I(t) is analyzed for various models. It is shown that in pure diffusive linear model case the flux is proportional to the classical Cottrelian Ic(t). Similar relationship is derived in the case of nonlinear model including diffusion and migration. These results suggest acceptability of the flux data as a measured output data in ion transport problems, instead of nonlocal additional condition in the form an integral of concentration function. In pure diffusive and diffusive-convective linear models cases, explicit analytical formulas between inputs (diffusion or/and convection coefficients) and output (measured flux data) are derived. The proposed analytical approach permits one to determine the unknown diffusion coefficient from a single flux data given at a fixed time t1 > 0, and unknown convection coefficient from a single flux data given at a fixed time t2 > t1 > 0. Linearized model of the nonlinear ion transport problem with variable diffusion and convection coefficients is analyzed. It is shown that the measured output (flux) data can not be given arbitrarily. © 2010 Springer Science+Business Media, LLC. Source

Tarlaci S.,Izmir University | Pregnolato M.,University of Pavia
International Journal of Psychophysiology | Year: 2015

The concepts of quantum brain, quantum mind and quantum consciousness have been increasingly gaining currency in recent years, both in scientific papers and in the popular press. In fact, the concept of the quantum brain is a general framework. Included in it are basically four main sub-headings. These are often incorrectly used interchangeably. The first of these and the one which started the quantum mind/consciousness debate was the place of consciousness in the problem of measurement in quantum mechanics. Debate on the problem of quantum measurement and about the place of the conscious observer has lasted almost a century. One solution to this problem is that the participation of a conscious observer in the experiment will radically change our understanding of the universe and our relationship with the outside world. The second topic is that of quantum biology. This topic has become a popular field of research, especially in the last decade. It concerns whether or not the rules of quantum physics operate in biological structures. It has been shown in the latest research on photosynthesis, the sense of smell and magnetic direction finding in animals that the laws of quantum physics may operate in warm-wet-noisy biological structures. The third sub-heading is quantum neurobiology. This topic has not yet gained wide acceptance and is still in its early stages. Its primary purpose is directed to understand whether the laws of quantum physics are effective in the biology of the nervous system or not. A further step in brain neurobiology, towards the understanding of consciousness formation, is the research of quantum laws' effects upon neural network functions. The fourth and final topic is quantum psychopathology. This topic takes its basis and its support from quantum neurobiology. It comes from the idea that if quantum physics is involved in the normal working of the brain, diseased conditions of the brain such as depression, anxiety, dementia, schizophrenia and hallucinations can be explained by quantum physical pathology. In this article, these topics will be reviewed in a general framework, and for the first time a general classification will be made for the quantum brain theory. © 2015 Elsevier B.V. Source

Kobak S.,Izmir University
Therapeutic Advances in Musculoskeletal Disease | Year: 2015

Sarcoidosis is a systemic disorder of unknown etiology, which may involve various tissues and organs and is characterized by a noncaseating granuloma reaction. While pathogenesis is not yet clear, cellular immune system activation and nonspecific inflammatory response occur secondarily to several genetic and environmental factors. T helper 1-cells and macrophage-derived pro-inflammatory cytokines stimulate the inflammatory cascade and formation of granuloma occurs as a result of tissue permeability, cell influx, and local cell proliferation. The different prevalence, clinical results, and disease course observed in different races and ethnic groups, is an indicator of the heterogeneous nature of the disease. Sarcoidosis may mimic and/or may occur concomitantly with numerous primary rheumatic diseases. This disease most commonly presents with bilateral hilar lymphadenopathy, pulmonary infiltrations, and skin and eye lesions. Locomotor system involvement is observed at a range of 15% and 25%. Two major joint involvements have been described: acute and chronic form. The most common form, the acute form, may be the first sign of sarcoidosis and present with arthralgia, arthritis, or periarthritis. Chronic sarcoid arthritis is usually associated with pulmonary parenchymal disease or other organ involvement and occurs rarely. While asymptomatic muscular involvement is reported between 25% and 75%, symptomatic muscular involvement is very rare. Symptomatic myopathy may present as three different types: chronic myopathy, palpable nodular myositis, or acute myositis. Even if rare, 2–5% of cases may exhibit osseous involvement and it is frequently associated with lupus pernio, chronic uveitis, and multisystemic disease. Sarcoidosis was reported together with different rheumatologic diseases. There are studies showing that sarcoidosis may mimic the clinical and laboratory findings of these disorders. Nonsteroidal anti-inflammatory drugs and corticosteroids are used for treating the symptoms of rheumatologic findings. In patients who are unresponsive to corticosteroids, immunosuppressive and anti-tumor necrosis factor alpha drugs may be used. In this review, the incidence of rheumatologic symptoms, the clinical findings, and the treatment of rheumatologic manifestations of sarcoidosis are discussed. © 2015, © The Author(s), 2015. Source

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