Moment method

We demonstrate analytically and numerically that a subwavelength-core dielectric photonic nanowire embedded in a properly designed photonic crystal fiber cladding shows evidence of a previously unknown kind of nonlinearity (the magnitude of which is strongly dependent on the waveguide parameters) which acts on solitons so as to considerably reduce their Raman self-frequency shift. An explanation of the phenomenon in terms of indirect pulse negative chirping and broadening is given by using the moment method. Our conclusions are supported by detailed numerical simulations.

The depth-duration-frequency curves and isopluvial maps for the region encompassing South Carolina, North Carolina, and Georgia were developed using the available rainfall data. The aim was to update the existing intensity-duration-frequency curves in the region and obtain these curves at ungauged sites throughout the region using the newly developed rainfall frequency analysis techniques. A total of 17 durations ranging from 15 minutes to 120 hours for return periods of 2, 10, 25, 50, and 100 years were analyzed. The L-moment method with X-10 test was used to search for homogeneous regions within the study area. It was found that the method was either unable to homogeneous regions that were geographically contiguous or too many stations had to be eliminated before a region could be considered homogenous. Finally, at-site statistics were calculated to develop frequency relationships. Normal, lognormal, generalized extreme value, Pearson type III, and log Pearson type III probability distribution functions were used to fit the maximum annual precipitation data at each gauging site for each duration. The chi-squared goodness-of-fit test was used to determine the best fit probability distribution. The new intensity-duration-frequency curves were found to be lower than the existing curves developed in 1986. The difference between the two set of curves was found to be due to the removal of the outliers in the present study and the existence of the post 1986 drought conditions in the region. The spatial interpolation of the rainfall intensity from the depthduration-frequency curves was found to yield accurate intensity-duration-frequency curves and could be used to develop these curves at ungauged sites in the study area.

Stochastic multi objective programming problems commonly arise in complex systems such as portfolio analysis, medium-to long-term capacity planning and design applications under uncertainty. The identification of the candidate solution set is a main step in many applications which depends on the nature of uncertainty. This study presents a method to generate Pareto surface for multi-objective integer programs with stochastic coefficients in the objective functions based on minimum expectation and variance criteria. The objective function coefficients are represented through random discrete distributions. The methodology follows a two-phase approach where, in the first phase, the stochastic multiple objectives are converted into deterministic equivalents based on the minimum expectation and variance efficiency concepts. The second phase solves the deterministic multi objective problem, using a Pareto generation methodology which aims at generating the whole Pareto surface of multi objective integer programming problems. We present results of experimental study of applying the proposed method to an assignment problem with three objective functions.

It has been recently shown that puzzling excess events observed by the LSND and MiniBooNE neutrino experiments could be interpreted as a signal from the radiative decay of a heavy sterile neutrino ($\nu_h$) of the mass from 40 to 80 MeV, with a muonic mixing strength $\mix \simeq 10^{-3} - 10^{-2}$, and the lifetime $10^{-11} < \tau_h < 10^{-9}$ s. We discuss bounds on $\mix$ obtained from the recent precision measurements with muons and show that they are consistent with the above limits. If the $\nu_h$ exists its admixture in the ordinary muon or kaon decay would result in the decay chain $\muhd$ or $\khd$, respectively. We propose a new experiment for a sensitive search for these processes in $\mu$ and $K$ decays at rest allowing to either definitively confirm or exclude the existence of the $\nu_h$. To our knowledge, no experiment has specifically searched for the signature of radiative decay of massive neutrinos from particles decays as proposed in this work. The search i...

It has been recently suggested that the anomalous excess of low-energy electron-like events observed by the MiniBooNE experiment, could be explained by the radiative decay of a heavy sterile neutrino ν h of the mass around 500 MeV with a muonic mixing strength in the range |U µh | 2 ≃ (1 -4) × 10 -3 . If such ν h exists its admixtures in the decay D + s → µ + νµ would result in the decay D + s → µ + ν h with the branching fraction Br(D + s → µ + ν h ) ≃ (1.2 -5.5) × 10 -4 , which is in the experimentally accessible range. Interestingly, the existence of the D + s → µ + ν h decay at this level may also explain why the currently measured decay rate of D + s → µ + νµ is slightly higher than the predicted one. This enhances motivation for a sensitive search for this decay mode and makes it interesting and complementary to neutrino experiments probing sterile-active neutrino mixing. Considering, as an example the CLEO-c experiment, we suggest to perform a search for the decay D + s → µ + ν h with the analysis of existing data. The discrepancy between the measurements and theoretical description of the decay D + s → τ + ντ is also discussed in brief.

The anomaly in the low energy distribution of quasi-elastic neutrino events reported by the Mini-BooNE collaboration is discussed. We show that the observed excess of electron-like events could originate from the production and decay of a heavy neutrino (ν h ) in the MiniBooNE detector. The ν h is created by mixing in νµ neutral-current interactions and decays radiatively into νγ due to a transition magnetic moment between the ν h and a light neutrino ν. The energy measured in the detector arises from the subsequent conversion of the decay photon into a e + e -pair within the detector volume. The analysis of the energy and angular distributions of the excess events suggests that the ν h has a mass around 500 MeV and the lifetime τν h 10 -9 s. Existing experimental data are found to be consistent with a mixing strength between the ν h and the νµ of |U µh | 2 ≃ (1-4)×10 -3 and a ν h transition magnetic moment of µtr ≃ (1 -6) × 10 -9 µB. Finally, we discuss the reason why no significant excess of low energy events has been observed in the recent antineutrino data.

This paper proposes a quantum algorithm for solving the tautology and the satisfiability problems for a Boolean formula. Let's say we are given a Boolean formula. The variables of the Boolean formula can take only two values-TRUE or FALSE. The tautology problem asks whether the Boolean formula always evaluates to TRUE for all values of its Boolean variables. The satisfiability problem asks whether the Boolean formula can evaluate to TRUE for at least one set of values of its Boolean variables. This paper proposes that both problems can be solved using the proposed quantum algorithm. The tautology problem is known to be co-NP-complete. The satisfiability problem is known to be NP-complete.

Le LNE dispose d'une installation de référence pour la mesure de la diffusivité thermique basée sur la méthode « flash ». Cette caractéristique est déterminée par identification du thermogramme expérimental à un thermogramme théorique selon la méthode des moments temporels partiels. L'évaluation détaillée des composantes de l'incertitude de mesure de la diffusivité thermique est décrite dans ce document pour quelques matériaux homogènes, isotropes et opaques sur le domaine des températures comprises entre 20 °C et 1 400 °C. Cette étude montre qu'il est difficile d'effectuer des mesures de diffusivité thermique avec une incertitude inférieure à 3 % en utilisant cette méthode. Des mesures réalisées sur cinq matériaux différents illustrent cette démarche.

International guidelines and standards on whole-body radio-frequency (RF) dosimetry use the whole-body averaged specific absorption rate (WBA-SAR) as a surrogate metric to quantify the temperature rise in the body. This study proposes the analysis of whole-body RF dosimetry for far-field exposure of a grounded human body in the frequency range of 1-150 MHz based on a semianalytic approach of cylindrical antenna theory. The human body is represented by a lossy homogeneous cylindrical monopole antenna. For the first time, an explicit model for the resonance frequency of a grounded human body is proposed. The model captures the effects of the human body weight, height, and the dielectric properties. This study also addresses the effect of shoes on WBA-SAR. It is found that the resonance frequency for the WBA-SAR with shoe effect is higher than reported from using the bare-footed models, as confirmed by theory and measurement.

The calculation of the nonresonant Raman spectrum of double-walled carbon nanotubes ͑DWCNT's͒ is performed in the framework of the bond polarization theory, using the spectral moment method. The calculation of the Raman spectrum of DWCNT's as a function of the diameter and chirality of the inner and outer tubes allows us to derive the diameter dependence of the frequencies of the breathing-like modes ͑BLM's͒ and tangential-like modes ͑TLM's͒ in a large diameter range. In particular, the diameter dependence of the frequencies of the two radial breathing-like modes ͑RBLM's͒ resulting from the in-phase and counterphase coupled motions of the totally symmetric radial breathing mode ͑the so-called RBM͒ of the inner and outer tubes is discussed. The Raman spectrum of a bundle of identical DWCNT's is also calculated. The dependence of the spectrum with the size of the bundle is analyzed. Additional breathing-like modes are predicted in DWCNT bundles of finite size. The majority of these peaks rapidly vanish when the tube length increases, except a totally symmetric mode that subsists in the DWCNT crystal.

We report on minimum energy calculations, using a convenient Lennard-Jones expression of the van der Waals intermolecular potential, to derive the optimum configurations of C 60 molecules inside single wall carbon nanotubes. Depending on the diameter of the nanotube, C 60 molecules were found to form linear or zigzag chains inside the nanotubes. In the following, we use the spectral moments method, together with a bond-polarizability model, to calculate the nonresonant Raman spectrum for infinitely long isolated C 60 peapods. We present the evolution of the Raman spectrum as a function of the diameter and chirality of the nanotube. The changes of the Raman spectrum as a function of the configuration of the C 60 molecules inside the nanotubes are identified. On the other hand, the effect of the filling factor on the Raman spectrum is analyzed. These predictions are useful to interpret the experimental Raman spectra of fullerene peapods.

This paper investigates the effects of high-frequency radio waves on human exposure in wireless power transfer systems health impacts due to high-frequency radiation exposure, particularly examining induced electric fields, transmitted power density and specific absorption rates at frequencies of 6.78 MHz and 86.33 MHz. Comparisons were made between a simplified cylindrical model and a realistic human body model. The analytical approach assumes a sinusoidal current distribution along the cylinder. Numerical simulations, performed with the commercial software FEKO, validated the analytical findings presented. The results indicate that the analytical model shows good agreement with the numerical simulations, with differences generally within 10% for average specific absorption rate values. However, discrepancies are more pronounced in localized regions of high field intensity and when using the realistic human model. This consistency suggests that analytical methods offer a reliable, and rapid estimation for assessing compliance with exposure standards.

Analytical investigations of the problem of dielectriccoated thin-wire antenna structures have invariably focused on the physics of developing appropriate models for the dielectric insulation on the thin-wire conductors that serve as antenna for the structure. These include the frequency domain moment-method-based approaches in which the dielectric insulation is replaced by equivalent volume polarization currents; and the time-domain analysis based on the 'equivalent radius' concept. An earlier paper gave a physical interpretation to the frequency-domain solutions to suggest that the volume polarization currents derive from an equivalent static charge distribution, which excites an essentially radially-directed quasi-static field, confined to the region associated with the dielectric insulation. It is the main objective of this paper to investigate the veracity of the claims made in open literature as they concern the physics of the model for the dielectric insulation in terms of the electric field excited in the dielectric region. And to that end, simulation experiments were carried out, using a commercial Transmission Line Matrix (TLM) Method code, with which the characteristic features of the radial and axial components of the electric field within the dielectric region were investigated. The simulation results obtained from the experiments suggest that the field in question is not only of the quasi-static variety, but that it is also characterized by an axial component that meets the

Context. Discovered in 1907, the Blazhko effect is a modulation of the light variations of about half of the RR Lyr stars. It has remained unexplained for over 100 years, despite more than a dozen proposed explanations. Today it represents an ongoing challenge in variable-star research. Aims. We propose a new explanation. It is based on the observation that Blazhko stars seem to be located in the region of the instability strip where fundamental and first overtone modes are excited at the same time. Methods. An analysis of nonlinear and nonadiabatic pulsation models of RR Lyrae stars shows that a specific shock (called first overtone shock) may be generated by the perturbation of the fundamental mode by the transient first overtone. Results. The first overtone shock induces a sharp slowdown of the atmospheric layers during their infalling motion. This slowdown in turn affects the compression rate on the deep photospheric layers and the intensity of the κ-mechanism. After an amplification phase, the intensity of the main shock wave before the Blazhko maximum becomes high enough to provoke large radiative losses. These can be at least equal to 70% of the total energy flux of the shock, which induces a small decrease of the effective temperature at each pulsation cycle. In these conditions, when the intensity of the main shock reaches its highest critical value at the Blazhko maximum, it completely desynchronizes the motion of the phostospheric layers. At this point, the atmosphere relaxes and reaches a new synchronous state that occurs at the Blazhko minimum. Conclusions. The combined effects of these two shocks on the atmosphere cause the Blazhko effect. This effect can only exist if the first overtone mode is excited together with the fundamental mode. Because the involved physical mechanisms are essentially nonlinear (shocks, atmospheric dynamics, radiative losses, mode excitations), the Blazhko process is expected to be unstable and irregular. Consequently, the Blazhko process has a specific random nature that is in contrast with the pulsation of non-Blazhko stars.