Modification of the EDXD method for diagnostics of polycrystalline and fine-grained media

The possibilities of using broadband X rays for diagnostics of the atomic structure of solids are considered. It is proposed to use virtual photons of the Coulomb field of a relativistic electron beam as primary probe radiationye

Сонет Емми Андієвської: індивідуально-авторська модифікація жанру

The paper analyzes artistic originality of the sonnets by Emma Andiievska written in the 21st century, with accent on her individual modifi cation of the genre and its evolution in the context of the world literature. Receptive aspects of the artist’s creative writing have been considered.У статті проаналізовано художню своєрідність сонетарію Емми Андієвської ХХІ ст., специфіку індивідуально-авторської модифікації жанру, його еволюцію в контексті світової літератури. Розглянуто рецептивні аспекти творчості мисткині

Automated system design optimisation

The focus of this thesis is to develop a generic approach for solving reliability design optimisation problems which could be applicable to a diverse range of real engineering systems. The basic problem in optimal reliability design of a system is to explore the means of improving the system reliability within the bounds of available resources. Improving the reliability reduces the likelihood of system failure. The consequences of system failure can vary from minor inconvenience and cost to significant economic loss and personal injury. However any improvements made to the system are subject to the availability of resources, which are very often limited. The objective of the design optimisation problem analysed in this thesis is to minimise system unavailability (or unreliability if an unrepairable system is analysed) through the manipulation and assessment of all possible design alterations available, which are subject to constraints on resources and/or system performance requirements. This thesis describes a genetic algorithm-based technique developed to solve the optimisation problem. Since an explicit mathematical form can not be formulated to evaluate the objective function, the system unavailability (unreliability) is assessed using the fault tree method. Central to the optimisation algorithm are newly developed fault tree modification patterns (FTMPs). They are employed here to construct one fault tree representing all possible designs investigated, from the initial system design specified along with the design choices. This is then altered to represent the individual designs in question during the optimisation process. Failure probabilities for specified design cases are quantified by employing Binary Decision Diagrams (BDDs). A computer programme has been developed to automate the application of the optimisation approach to standard engineering safety systems. Its practicality is demonstrated through the consideration of two systems of increasing complexity; first a High Integrity Protection System (HIPS) followed by a Fire Water Deluge System (FWDS). The technique is then further-developed and applied to solve problems of multi-phased mission systems. Two systems are considered; first an unmanned aerial vehicle (UAV) and secondly a military vessel. The final part of this thesis focuses on continuing the development process by adapting the method to solve design optimisation problems for multiple multi-phased mission systems. Its application is demonstrated by considering an advanced UAV system involving multiple multi-phased flight missions. The applications discussed prove that the technique progressively developed in this thesis enables design optimisation problems to be solved for systems with different levels of complexity. A key contribution of this thesis is the development of a novel generic optimisation technique, embedding newly developed FTMPs, which is capable of optimising the reliability design for potentially any engineering system. Another key and novel contribution of this work is the capability to analyse and provide optimal design solutions for multiple multi-phase mission systems. Keywords: optimisation, system design, multi-phased mission system, reliability, genetic algorithm, fault tree, binary decision diagra

Multiphoton radiative recombination of electron assisted by laser field

In the presence of an intensive laser field the radiative recombination of the continuum electron into an atomic bound state generally is accompanied by absorption or emission of several laser quanta. The spectrum of emitted photons represents an equidistant pattern with the spacing equal to the laser frequency. The distribution of intensities in this spectrum is studied employing the Keldysh-type approximation, i.e. neglecting interaction of the impact electron with the atomic core in the initial continuum state. Within the adiabatic approximation the scale of emitted photon frequencies is subdivided into classically allowed and classically forbidden domains. The highest intensities correspond to emission frequencies close to the edges of classically allowed domain. The total cross section of electron recombination summed over all emitted photon channels exhibits negligible dependence on the laser field intensity.Comment: 14 pages, 5 figures (Figs.2-5 have "a" and "b" parts), Phys.Rev.A accepted for publication. Fig.2b is presented correctl

Atomic Bremsstrahlung: retrospectives, current status and perspectives

We describe here the Atomic bremsstrahlung - emission of continuous spectrum electromagnetic radiation, which is generated in collisions of particles that have internal deformable structure that includes positively and negatively charged constituents. The deformation of one of or both colliding partners induces multiple, mainly dipole, time-dependent electrical moments that become a source of radiation. The history of Atomic bremsstrahlung invention is presented and it's unusual in comparison to ordinary bremsstrahlung properties are discussed. As examples, fast electron - atom, non-relativistic and relativistic collisions are considered. Attention is given to ion - atom and atom - atom collisions. Specifics of elastic and inelastic (i.e. radiation accompanied by destruction of collision partners) Atomic bremsstrahlung will be mentioned. Attention will be given to possible manifestation of Atomic bremsstrahlung in Nature and in some exotic systems, for instance scattering of electrons upon muonic hydrogen. Some cooperative effects connected to Atomic bremsstrahlung will be considered. New classical schemes similar to Atomic bremsstrahlung will be presented.Comment: 29 pages, 11 figures Submitted to Electron spectroscopy and the related phenomen

System design optimisation involving phased missions

The performance of a phased mission is defined as a succession of non-overlapping phases that constitute towards a continuous mission. The focus of this paper is to develop a method to construct an optimal design structure for a phased mission system when available resources are restricted and to ensure a minimal system failure probability throughout the whole mission. The implemented optimisation method employs fault tree analysis to represent the causes of failure in the system for each phase. Binary decision diagrams are used to quantify the failure probability of each phase and the whole mission, and a single objective genetic algorithm is chosen to solve the optimisation problem. Analysis of the optimisation process of a military vessel design during a training mission is presented and the obtained results are discussed