Localization and Fluctuations in Quantum Kicked Rotors

We address the issue of fluctuations, about an exponential lineshape, in a pair of one-dimensional kicked quantum systems exhibiting dynamical localization. An exact renormalization scheme establishes the fractal character of the fluctuations and provides a new method to compute the localization length in terms of the fluctuations. In the case of a linear rotor, the fluctuations are independent of the kicking parameter $k$ and exhibit self-similarity for certain values of the quasienergy. For given $k$, the asymptotic localization length is a good characteristic of the localized lineshapes for all quasienergies. This is in stark contrast to the quadratic rotor, where the fluctuations depend upon the strength of the kicking and exhibit local "resonances". These resonances result in strong deviations of the localization length from the asymptotic value. The consequences are particularly pronounced when considering the time evolution of a packet made up of several quasienergy states.Comment: REVTEV Document. 9 pages, 4 figures submitted to PR

A Navier-Stokes Solution of Hull-Ring Wing-Thruster Interaction

Navier-Stokes simulations of high Reynolds number flow around an axisymmetric body supported in a water tunnel were made. The numerical method is based on a finite-differencing high resolution second-order accurate implicit upwind scheme. Four different configurations were investigated, these are: (1) barebody; (2) body with an operating propeller; (3) body with a ring wing; and (4) body with a ring wing and an operating propeller. Pressure and velocity components near the stern region were obtained computationally and are shown to compare favorably with the experimental data. The method correctly predicts the existence and extent of stern flow separation for the barebody and the absence of flow separation for the three other configurations with ring wing and/or propeller

Possibility of Turbulent Crystals

The possibility for the occurrence in crystals of a phenomenon, resembling turbulence, is discussed. This phenomenon, called {\it heterophase turbulence}, is manifested by the fluctuational appearance inside a crystalline sample of disordered regions randomly distributed in space. The averaged picture for such a turbulent solid is exemplified by an exactly solvable lattice-gas model. The origin of heterophase turbulence is connected with stochastic instability of quasi-isolated systems.Comment: Latex file, 20 pages, no figure

A PROSPECTIVE STUDY ON THE EFFICACY OF METFORMIN IN OBESE AND NON-OBESE PATIENTS WITH POLYCYSTIC OVARY SYNDROME

ABSTRACTObjective: The aim of the study was to assess the efficacy of metformin on fasting blood glucose (FBG), postprandial blood glucose (PPBG), totalcholesterol (T. chol), blood pressure (BP), weight and hence body mass index (BMI) in women with polycystic ovary syndrome (PCOS).Methods: In a prospective study, 90 women aged 18-45 were treated with metformin 500 mg twice daily for 1 year. women were grouped as obeseand non-obese based on their BMI. The changes in measured parameters were analyzed statistically.Results: There was a reduction in weight, systolic BP (SBP), FBG, PPBG and T. chol (p=0.04, p=0.03, p=0.032, p=0.037, p=0.042 and p=0.047,respectively) in the obese group. There was no significant difference in diastolic BP in both the groups.Conclusion: Metformin treatment lowered weight and SBP and T. chol in women with PCOS. FBG and PPBG were also reduced in obese patients whileNon-obese women did not benefit from metformin.Keywords: Polycystic ovary syndrome, Metformin, Obese, Non-obese

Quantized Orbits and Resonant Transport

A tight binding representation of the kicked Harper model is used to obtain an integrable semiclassical Hamiltonian consisting of degenerate "quantized" orbits. New orbits appear when renormalized Harper parameters cross integer multiples of $\pi/2$. Commensurability relations between the orbit frequencies are shown to correlate with the emergence of accelerator modes in the classical phase space of the original kicked problem. The signature of this resonant transport is seen in both classical and quantum behavior. An important feature of our analysis is the emergence of a natural scaling relating classical and quantum couplings which is necessary for establishing correspondence.Comment: REVTEX document - 8 pages + 3 postscript figures. Submitted to Phys.Rev.Let

Thermal regulation of building-integrated concentrating photovoltaic system using phase change material

This is the final version. Available from AIP Publishing via the DOI in this record12th International Conference on Concentrator Photovoltaic Systems (CPV-12), 25-27 April 2016, Freiburg, GermanyThermal regulation of building-integrated concentrating photovoltaic (BICPV) systems have a direct influence on the photovoltaic performance. This paper investigates the thermal behavior of a BICPV and phase change material (PCM) system through numerical modeling simulations. Based on an updated mathematical model, theoretical simulation has been conducted for a BICPV-PCM system. The results show a 3% electrical efficiency improvement of the BICPV-PCM system in certain cases.Ministry of Higher Education, Sultanate of Oma

Conditions for the Quantum to Classical Transition: Trajectories vs. Phase Space Distributions

We contrast two sets of conditions that govern the transition in which classical dynamics emerges from the evolution of a quantum system. The first was derived by considering the trajectories seen by an observer (dubbed the ``strong'' transition) [Bhattacharya, et al., Phys. Rev. Lett. 85: 4852 (2000)], and the second by considering phase-space densities (the ``weak'' transition) [Greenbaum, et al., Chaos 15, 033302 (2005)]. On the face of it these conditions appear rather different. We show, however, that in the semiclassical regime, in which the action of the system is large compared to $\hbar$, and the measurement noise is small, they both offer an essentially equivalent local picture. Within this regime, the weak conditions dominate while in the opposite regime where the action is not much larger than Planck's constant, the strong conditions dominate.Comment: 8 pages, 2 eps figure