Leptogenesis in flavor models with type I and II seesaws

In type I seesaw models with flavor symmetries accounting for the lepton mixing angles the CP asymmetry in right-handed neutrino decays vanishes in the limit in which the mixing pattern is exact. We study the implications that additional degrees of freedom from type II seesaw may have for leptogenesis in such a limit. We classify in a model independent way the possible realizations of type I and II seesaw schemes, differentiating between classes in which leptogenesis is viable or not. We point out that even with the interplay of type I and II seesaws there are generic classes of minimal models in which the CP asymmetry vanishes. Finally we analyze the generation of the lepton asymmetry by solving the corresponding kinetic equations in the general case of a mild hierarchy between the light right-handed neutrino and the scalar triplet masses. We identify the possible scenarios in which leptogenesis can take place.     

A new method to approximate the field of movements of 1-DOF linkages with lower-pairs

This paper presents a new method to obtain an approximation of the field of movements of 1-DOF linkages with lower pairs. The method is based on a linkage representation by natural coordinates and the storage of the constraint equations by means of a sparse cubic matrix. To obtain a discrete approximation of the field of movements, a three-stage process is used. In the first stage, a special Evolution Strategy is applied to make the population converges towards the zones where the constraints’ error is minimal, obtaining, at the same time, a good distribution of individuals. In the second stage, the final individuals of the ES are used as initial points for an optimization algorithm to obtain a greater accuracy. Later, the third stage is a filtering process to eliminate individuals that represent non-desired solutions. This method has been tested on some linkages with well-known fields of movements, generating comprehensive outcomes that justify the validity of the method.     

Landau levels and Riemann zeros

The number N(E) of complex zeros of the Riemann zeta function with positive imaginary part less than E is the sum of a "smooth" function N[over ](E) and a "fluctuation." Berry and Keating have shown that the asymptotic expansion of N[over ](E) counts states of positive energy less than E in a "regularized" semiclassical model with classical Hamiltonian H=xp. For a different regularization, Connes has shown that it counts states "missing" from a continuum. Here we show how the "absorption spectrum" model of Connes emerges as the lowest Landau level limit of a specific quantum-mechanical model for a charged particle on a planar surface in an electric potential and uniform magnetic field. We suggest a role for the higher Landau levels in the fluctuation part of N(E).     

Models for capacitated lot-sizing problem with backlogging,setup carryover and crossover

Setup operations are significant in some production environments. It is mandatory that their production plans consider some features, as setup state conservation across periods through setup carryover and crossover. The modelling of setup crossover allows more flexible decisions and is essential for problems with long setup times. This paper proposes two models for the capacitated lot-sizing problem with backlogging and setup carryover and crossover. The first is in line with other models from the literature, whereas the second considers a disaggregated setup variable, which tracks the starting and completion times of the setup operation. This innovative approach permits a more compact formulation. Computational results show that the proposed models have outperformed other state-of-the-art formulation.     

Nehari-type families of harmonic mappings

We introduce affine and linearly invariant families of locally injective harmonic mappings of the unit disk $\mathbb{D}$. We derive sharp distortion theorems for the Jacobian that are used to establish a uniform modulus of continuity for the quasiconformal mappings in each class. Finally, we find a converse of a recent theorem of Chen and Ponnusamy characterizing when the image $f(\mathbb{D})$ under a quasiconformal harmonic univalent mapping is a John domain.     

Preparation, structural analysis and dielectric properties of Bi x La1−x FeO3 perovskite

Rare earth element substituted bismuth ferrites (BiFeO₃) are of enormous importance as magnetoelectric materials. The polycrystalline samples of Bi _x La_1−x FeO₃ (x=0, 0.2, 0.4, 0.6, 0.8) were prepared by solid-state reaction using standard ceramic method. The single-phase formation of these compounds was confirmed by X-ray diffraction (XRD) studies. The samples with x=0, 0.2, 0.4, 0.6 are found to be orthorhombic while the sample with x=0.8 is triclinic. The dielectric constant (ε′) and dissipation factor (tan δ) were measured in the frequency range 100 Hz to 1 MHz at room temperature and as a function of temperature at certain fixed frequencies (1 kHz, 10 kHz, 100 kHz, 1 MHz). All the samples showed dielectric dispersion. The dielectric constant with temperature shows a broad peak; the peak temperature shifts with frequency which reflects the relaxor-type behavior. The peak above 600 K in the measured temperature range corresponds to antiferromagnetic ordering temperature (Néel temperature). The broadness of the peak changes with composition. The ac conductivity as well as ε′ are found to be maximum for the sample x=0.2 at room temperature.     

A high‐level theoretical study into the atmospheric phase hydration,bond dissociation enthalpies,and acidity of aldehydes

CBS‐Q//B3, G4(MP2), and G4 composite method calculations were used to estimate atmospheric phase standard state (298.15 K, 1 atm) free energies of hydration (Δ_hydrG°_(g)), hydration equilibrium constants (log K_hydr,(g)), bond dissociation enthalpies (BDEs), and enthalpies (Δ_dH°_(g)) and free energies (Δ_dG°_(g)) of aldehydic proton acid dissociation for various substituted aldehydes with electron withdrawing and electron releasing groups. Good quality log K_hydr,(g) correlations with the Swain–Lupton resonance effect parameters R and R⁺ were found, allowing extension of the model to predict log K_hydr,(g) values for 487 substituted aldehydes having available R‐values and 108 substituted aldehydes having available R⁺ values. Good correlations were also found between experimental aqueous phase hydration equilibrium constants (log K_hydr,(aq)) and summative R/R⁺ values for peripheral substituents on a range of carbonyl derivatives (aldehydes, ketones, esters, and amides), suggesting that the structure–reactivity modeling approach can be extended to include all possible combinations of R₁C(O)R₂ carbonyl substitution in both gas and aqueous systems. Computationally derived BDEs and Δ_dH°_(g)/Δ_dG°_(g) were in good agreement with the limited experimental and theoretical datasets. BDEs did not generally correlate with any of the Hammett substituent constants or Swain–Lupton parameters considered. Gas phase acidities exhibited high correlation coefficients with Hammett inductive substituent constants (σ_I) and field effect parameters (F), allowing these to be employed as surrogates for estimating the gas phase aldehydic proton acidities of a larger potential compound range. The resulting models will be of use in predicting the environmental behavior for a broad range of environmentally relevant compounds containing carbonyl functionalities. Copyright © 2016 John Wiley & Sons, Ltd.     

Analysis of Li distribution in ultrathin all-solid-state Li-ion battery (ASSLiB) by neutron depth profiling (NDP)

Lithium-ion batteries are promising energy storage technology devices. They possess many advantages, including high energy density, flexible and lightweight construction and considerable durability. The rapid development of nanotechnologies can further improve their capacity, cycle life and safety. In this experiment, Li-ion diffusion in an all-solid lithium-ion battery (ASSLiB) was studied using the Neutron Depth Profiling (NDP) nuclear analytical technique. The thin ASSLiB system was synthesised by RF magnetron sputtering. The experiment showed that NDP is a very efficient experimental tool for direct analysis of Li distribution in Li batteries. It has been found that the depth profile of Li strongly depends on the state of charge of the battery. About one-third of the total number of Li in ASSLiB can move between the electrodes during charging / discharging. It has been also shown, using the multipixel detectors, that the lateral distribution of Li in ASSLiB is not homogeneous. This can mean, for example, that the position of Li is affected by structural defects that may arise due to variation of the volume or stress of the battery during charging or discharging. In the work are presented first results of measurements performed on ASSLiB of a 1?µm thickness.     

Magnetoelectric effect in cobalt ferrite-barium titanate composites and their electrical properties

CoFe₂O₄-BaTiO₃ composites were prepared using conventional ceramic double sintering process with various compositions. Presence of two phases in the composites was confirmed using X-ray diffraction. The dc resistivity and thermoemf as a function of temperature in the temperature range 300 K to 600 K were measured. Variation of dielectric constant (ɛ′) with frequency in the range 100 Hz to 1 MHz and also with temperature at a fixed frequency of 1 kHz was studied. The ac conductivity was derived from dielectric constant (ɛ′) and loss tangent (tan δ). The nature of conduction is discussed on the basis of small polaron hopping model. The static value of magnetoelectric conversion factor has been studied as a function of magnetic field.     

On a KdV equation with higher-order nonlinearity: Traveling wave solutions

In this work, the improved tanh-coth method is used to obtain wave solutions to a Korteweg-de Vries (KdV) equation with higher-order nonlinearity, from which the standard KdV and the modified Korteweg-de Vries (mKdV) equations with variable coefficients can be derived as particular cases. However, the model studied here include other important equations with applications in several fields of physical and nonlinear sciences. Periodic and soliton solutions are formally derived.