Damage in textile laminates of various inter-ply shift

Deformation mechanisms and failure of textile laminates are strongly affected by inter-layer configurations – a mutual shift of the plies. To model it within a traditional framework, one must construct a representative volume element (RVE), which includes all the plies. This is a time consuming and computationally expensive work. As an alternative, the paper suggests boundary conditions (BC) imitating the interaction with the surrounding non-periodic media. This makes possible analysis on a single unit cell of one ply. The proposed BC respect inter-ply configurations, account for the number of plies, distinguish the ply position, and reproduce the meso stress state with a good accuracy. The BC are constructed through (1) averaging of the known periodic solutions with respect to the ply shifts, (2) separation of the solution to the outer and inner ply cases, (3) energy equilibrium of heterogeneous and effective media. The unit cell finite element (FE) modelling is validated by reference full scale solution on the entire laminate

Improved theoretical prediction for the 2s hyperfine interval in helium ion

We consider the uncertainty of theoretical calculations for a specific difference of the hyperfine intervals in the 1s and 2s states in a light hydrogen-like atom. For a number of crucial radiative corrections the result for hydrogen atom and helium ion appears as an extrapolation of the numerical data from medium to low Z. An approach to a plausible estimation of the uncertainty is suggested using the example of the difference $D_{21}= 8E_{hfs}(2s)-E_{hfs}(1s)$

Novel method for functionalising and patterning textile composites:Liquid resin print

AbstractThe paper reports a novel method of integrating resin into continuous textile reinforcement. The method presents a print of liquid reactive resin into textile preforms. A series of targeted injections forms a patch which upon consolidation and curing transforms into a stiff region continuously spanning through preform thickness. Enhancing the injected resin with conductive phase allows creating a pattern of patches with controlled dimensions and added functionalities. Patterned composites reveal features which are not typical for conventional composites such as fibre bridged interfaces, regular thickness variation, and gradient matrix properties. The presented study explores the role of these features in (a) the mechanical behaviour of these materials, focusing on their deformation and failure mechanisms in tension, and (b) the feasibility of adding functionality by printing electrically conductive resins containing carbon nano-tubes (CNT). It was shown that resin print is a promising method for local functionalization of structural composites

Study of hyperfine structure in simple atoms and precision tests of the bound state QED

We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.Comment: presented at The International Workshop "e+e- collisions from phi to psi

Some Recent Advances in Bound-State Quantum Electrodynamics

We discuss recent progress in various problems related to bound-state quantum electrodynamics: the bound-electron g factor, two-loop self-energy corrections and the laser-dressed Lamb shift. The progress relies on various advances in the bound-state formalism, including ideas inspired by effective field theories such as Nonrelativistic Quantum Electrodynamics. Radiative corrections in dynamical processes represent a promising field for further investigations.Comment: 12 pages, nrc1 LaTeX styl

Методы анализа микроальтернации ЭКГ-сигнала

The paper presents the methods of analysis of the ECG-signal alternations, which are increasingly being used in everyday clinical practice. Evaluation of these indicators is an important component of the analysis of myocardial electrical instability and the development of potentially dangerous arrhythmias. New technologies of reception and analysis of the electric field of the heart reflect the creation of a new generation of functional diagnostic methods. Now the method of dispersion mapping is increasingly being used for the screening in Russia.В работе представлены используемые методы анализа альтернаций ЭКГ-сигнала, которые все шире используются в повседневной клинической практике. Оценка данных показателей является важной составляющей анализа электрической нестабильности миокарда и развития потенциально-опасных аритмий. Новые технологии получения и анализа электрического поля сердца отражают создание нового поколения методов функциональной диагностики. Метод дисперсионного картирования находит все большее применение в РФ в настоящее время для проведения скрининга

Double-Logarithmic Two-Loop Self-Energy Corrections to the Lamb Shift

Self-energy corrections involving logarithms of the parameter Zalpha can often be derived within a simplified approach, avoiding calculational difficulties typical of the problematic non-logarithmic corrections (as customary in bound-state quantum electrodynamics, we denote by Z the nuclear charge number, and by alpha the fine-structure constant). For some logarithmic corrections, it is sufficient to consider internal properties of the electron characterized by form factors. We provide a detailed derivation of related self-energy ``potentials'' that give rise to the logarithmic corrections; these potentials are local in coordinate space. We focus on the double-logarithmic two-loop coefficient B_62 for P states and states with higher angular momenta in hydrogenlike systems. We complement the discussion by a systematic derivation of B_62 based on nonrelativistic quantum electrodynamics (NRQED). In particular, we find that an additional double logarithm generated by the loop-after-loop diagram cancels when the entire gauge-invariant set of two-loop self-energy diagrams is considered. This double logarithm is not contained in the effective-potential approach.Comment: 14 pages, 1 figure; references added and typographical errors corrected; to appear in Phys. Rev.

Gravitation and inertia; a rearrangement of vacuum in gravity

We address the gravitation and inertia in the framework of 'general gauge principle', which accounts for 'gravitation gauge group' generated by hidden local internal symmetry implemented on the flat space. We connect this group to nonlinear realization of the Lie group of 'distortion' of local internal properties of six-dimensional flat space, which is assumed as a toy model underlying four-dimensional Minkowski space. The agreement between proposed gravitational theory and available observational verifications is satisfactory. We construct relativistic field theory of inertia and derive the relativistic law of inertia. This theory furnishes justification for introduction of the Principle of Equivalence. We address the rearrangement of vacuum state in gravity resulting from these ideas.Comment: 17 pages, no figures, revtex4, Accepted for publication in Astrophys. Space Sc

Leading Chiral Logarithms to the Hyperfine Splitting of the Hydrogen and Muonic Hydrogen

We study the hydrogen and muonic hydrogen within an effective field theory framework. We perform the matching between heavy baryon effective theory coupled to photons and leptons and the relevant effective field theory at atomic scales. This matching can be performed in a perturbative expansion in alpha, 1/m_p and the chiral counting. We then compute the O(m_{l_i}^3 alpha^5/m_p^2 x logarithms) contribution (including the leading chiral logarithms) to the Hyperfine splitting and compare with experiment. They can explain about 2/3 of the difference between experiment and the pure QED prediction when setting the renormalization scale at the rho mass. We give an estimate of the matching coefficient of the spin-dependent proton-lepton operator in heavy baryon effective theory.Comment: 17 pages, LaTeX, minor changes, one reference adde

Once in a blue moon: detection of ‘bluing’ during debris transits in the white dwarf WD 1145+017

The first transiting planetesimal orbiting a white dwarf was recently detected in K2 data of WD 1145+017 and has been followed up intensively. The multiple, long and variable transits suggest the transiting objects are dust clouds, probably produced by a disintegrating asteroid. In addition, the system contains circumstellar gas, evident by broad absorption lines, mostly in the u΄ band, and a dust disc, indicated by an infrared excess. Here we present the first detection of a change in colour of WD 1145+017 during transits, using simultaneous multiband fast-photometry ULTRACAM measurements over the u΄g΄r΄i΄ bands. The observations reveal what appears to be ‘bluing' during transits; transits are deeper in the redder bands, with a u΄ − r΄ colour difference of up to ∼−0.05 mag. We explore various possible explanations for the bluing, including limb darkening or peculiar dust properties. ‘Spectral' photometry obtained by integrating over bandpasses in the spectroscopic data in and out of transit, compared to the photometric data, shows that the observed colour difference is most likely the result of reduced circumstellar absorption in the spectrum during transits. This indicates that the transiting objects and the gas share the same line of sight and that the gas covers the white dwarf only partially, as would be expected if the gas, the transiting debris and the dust emitting the infrared excess are part of the same general disc structure (although possibly at different radii). In addition, we present the results of a week-long monitoring campaign of the system using a global network of telescopes