65 research outputs found

    Assessment of Aortic Pulse Wave Velocity and Cardiac Diastolic Function in Subjects With and Without the Metabolic Syndrome: HDL cholesterol is independently associated with cardiovascular function

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    OBJECTIVE—To evaluate the influence of lipid and glucose metabolism in the metabolic syndrome on aortic pulse wave velocity (PWV) and left ventricular (LV) diastolic function using magnetic resonance imaging (MRI)

    An exactly solvable quantum-lattice model with a tunable degree of nonlocality

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    An array of N subsequent Laguerre polynomials is interpreted as an eigenvector of a non-Hermitian tridiagonal Hamiltonian HH with real spectrum or, better said, of an exactly solvable N-site-lattice cryptohermitian Hamiltonian whose spectrum is known as equal to the set of zeros of the N-th Laguerre polynomial. The two key problems (viz., the one of the ambiguity and the one of the closed-form construction of all of the eligible inner products which make HH Hermitian in the respective {\em ad hoc} Hilbert spaces) are discussed. Then, for illustration, the first four simplest, kk-parametric definitions of inner products with k=0,k=1,k=2k=0,k=1,k=2 and k=3k=3 are explicitly displayed. In mathematical terms these alternative inner products may be perceived as alternative Hermitian conjugations of the initial N-plet of Laguerre polynomials. In physical terms the parameter kk may be interpreted as a measure of the "smearing of the lattice coordinates" in the model.Comment: 35 p

    Non-Hermitian Hamiltonians with a Real Spectrum and Their Physical Applications

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    We present an evaluation of some recent attempts at understanding the role of pseudo-Hermitian and PT-symmetric Hamiltonians in modeling unitary quantum systems and elaborate on a particular physical phenomenon whose discovery originated in the study of complex scattering potentials.Comment: 9 pages, contributed to Homi Bhabha Centenary Conference on Non-Hermitian Hamiltonians in Quantum Physics (8th International Workshop on Pseudo-Hermitian Hamiltonians in Quantum Physics), held in Mumbai, January 13-16, 200

    Properties of low frequency TE-electromagnetic wave in ternary plasma photonic crystal

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    In this study, the oblique incident of the electromagnetic waves with frequencies lower than plasma frequency in one dimensional ternary plasma photonic crystal has been investigated. The unit cell of crystal contains a plasma layer that is embedded in two different dielectric layers. Using the wave equation, Bloch theory, and boundary condition, the dispersion relation, the group velocity and the reflection relation of the structure have been obtained. Numerical results are presented in the form of dispersion curves. The dependence of photonic band gap characteristics on plasma frequency is discussed. One attempt has been made to show how the photonic band gap characteristic of a particular structure changes when the dielectric material of the unit cell is replaced by other dielectric materials or when the incident angle of the electromagnetic wave is changed. Results show that plasma layer characteristics has a significant effect on band gaps and wave propagation characteristics; also the results show that the proposed multi-layered structure can act as a tunable photonic crystal which can be controlled by the external parameters

    The real-time dynamic multi-objective optimization of a building integrated photovoltaic thermal (BIPV/T) system enhanced by phase change materials

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    Phase change material (PCM) is employed to enhance the thermal energy storage capacity of a building integrated photovoltaic thermal (BIPV/T) system. For this purpose, the best thickness of PCM is found using the dynamic multi-objective optimization (MOO), in which the performance throughout a year with real-time data is taken into account. In addition to the annual thermal energy storage capacity (AES), the annual energy (electricity) production (AEP), as well as payback period (PBP), the levelized cost (LCOE), and annual carbon-dioxide emission reduction (ACDR) are considered as the objective function to obtain a favorable condition from all the energy, economic, and environmental (3E) perspectives. MOO is done for a residential building in Tehran, Iran, by employing numerical modeling for system simulation and the combination of TOPSIS and NSGA-II techniques to determine the final optimal solution. According to the results, the best PCM thickness is 77.2 mm. Compared to the base condition, in which air is used as the material for energy storage, using PCM with the optimum thickness is accompanied by 22.24%, 9.93%, 17.69%, and 9.59% improvement in AES, AEP, ACDR, and LCOE, respectively. Moreover, PBP in the optimum condition is 3.321 years, which shows that utilizing the results of MOO is economically justifiable
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