The procedure of the specimen loading parameters in fixing video frame of crack profile

Цифрова відеозйомка, яка дозволяє здійснювати прямі вимірювання геометричних параметрів профілю тріщини широко застосовується в експериментальній механіці руйнування. Проте часто, особливо при вивченні швидкоплинних нестаціонарних процесів руйнування, за відсутності апаратного зв’язку відеокамери з випробувальною машиною виникає проблема встановлення значень, які мали параметри навантаження зразка у моменти фіксації відеокадрів профілю тріщини. Для вирішення цієї проблеми розроблено й перевірено відповідну методику.Digital videography, which makes it possible to accomplish direct measurements of geometric parameters of the crack profile in real time, finds wide use in experimental fracture mechanics. Practical implementation of videography in conducting experiments frequently faced difficulties due to the lack of synchronization between the processes of recording of the specimen loading parameters and videography. To solve this problem, a procedure for synchronization between the recording of the specimen loading parameters with an extending crack and videography of the crack profile using the testing machine controller together with digital CMOS-videocamera has been developed and approved. For mutual compliance of the loading and videography processes it is required to use some process, which is simultaneously recorded by means of controller and videocamera, as a binding element. For two registration systems this process occurs at initial instants of time (t0)mach and (t0)video. For any video frame at the instant time tvideo time interval since the beginning of videography is determined as Δt = tvideo – (t0)video. The loading parameters at this instant time is determined as tmach = (t0)mach + Δt. The instant of turn-off time for laser marker governed by digital controller output is used as such process. Thin-sheet metallic specimens have been tested for verification of synchronization. Measurements of the crack length are concurrently performed using the procedures of digital optical macrovideography and digital microvideography. The results of measurements of the crack length in accordance with both procedures are in a good agreement with each other

Magnetic vortex-antivortex crystals generated by spin-polarized current

We study vortex pattern formation in thin ferromagnetic films under the action of strong spin-polarized currents. Considering the currents which are polarized along the normal of the film plane, we determine the critical current above which the film goes to a saturated state with all magnetic moments being perpendicular to the film plane. We show that stable square vortex-antivortex superlattices (\emph{vortex crystals}) appears slightly below the critical current. The melting of the vortex crystal occurs with current further decreasing. A mechanism of current-induced periodic vortex-antivortex lattice formation is proposed. Micromagnetic simulations confirm our analytical results with a high accuracy.Comment: 12 pages, 11 figure

Current induced vortex superlattices in nanomagnets

Influence of the spin-transfer torque on the vortex state magnetic nanodisk is studied numerically via Slonczewski-Berger mechanism. The existence of a critical current is determined for the case of same-directed electrical current, its spin polarization and polarity of the vortex. The critical current separates two regimes: (i) deformed but static vortex state and (ii) essentially dynamic state under which the spatio-temporal periodic structures can appear. The structure is a stable vortex-antivortex lattice. Symmetry of the lattice depends on the applied current value and for high currents (close to saturation) only square lattices are observed. General relations for sizes of the stable lattice is obtained analytically.Comment: 4 pages, 3 figure

Initial Penetration of an Elastic Axially Symmetric Indenter into a Rigid-Perfectly-Plastic Half-Space

This paper is concerned with the axially symmetric plastic flow of a rigid perfectly-plastic nonhardening halfspace. The initial penetration of the elastic indenter is studied based on Haar and von Karman hypothesis. The analytical distribution of contact stress and the approximate penetration depth of the indenter are obtained

Development Of The Extraction Method Of Inactive Forms Of Pectin Substances From Fruits To Easy-digestible Active Form During The Obtaining Of Nanofood

The aim of the work is development of a unique method for deep processing of fruits and vegetables with a high content of sparingly soluble pectin substances, which makes it possible to remove pectic substances from inactive form and transform them into an easily digestible active form when obtaining natural semi-finished products and food products in nanosized form. To achieve the aim, a complex effect on the raw material of steam-thermal treatment or cryogenic shock freezing and fine-dispersed grinding is used as an innovation.A new method for obtaining finely dispersed additives and health products from fruits and vegetables with a high content of biologically active substances (BAS) and prebiotic substances is developed, which is based on a complex effect on raw materials of processes of steam-thermal or cryogenic treatment of raw materials and fine-dispersed grinding, which is accompanied by destruction, mechanochemistry, non-enzymatic catalysis. It is found that when these processes are activated, pectic substances are activated, more complete extraction from raw materials (4.5 ... 7.3 times) from a latent form and transformation into a soluble form. The mechanism of these processes is disclosed, recommendations for the creation of recreational nanoproducts are developed. It is shown that, in parallel, non-enzymatic catalysis (up to 70%) of hardly soluble pectic substances in individual monomers takes place, that is, transformation into a soluble, easily digestible form.The increase and seizures of latent forms of biologically active substances in finely dispersed frozen and heat-treated purees from fruit compared with fresh raw materials is established. The increase is respectively 1.5 ... 4.0 times and 1.5 ... 3.0 times. The quality of the obtained new types of fine mashed potatoes exceeds the known analogs for BAS content and technological characteristics. New types of purees are in a nanoscale, easily digestible form.With the use of new types of finely dispersed additives, a wide range of products for health-improving nutrition has been developed with a record content of natural BASs (new types of nano-lipids, nanosorb products, milk-vegetable cocktails, fillings for confectionery and extruded products, curd desserts, bakery products, snacks - falafel, creams, etc.)

Determination of the material parameters of the johnsoncook model for thin-sheet high-strength steel ARMOX 500T

The paper presents the results of complex experimental and computational studies of the behavior of thin-sheet high-strength steel ARMOX 500T under various types of load,which made it possible to determine the material parameters of the Johnson-Cook mode

Optimisation and comparison of transient expression methods to express the green fluorescent protein in the obligate biotrophic oomycete Plasmopara viticola

Grape downy mildew is caused by Plasmopara viticola, an obligate biotrophic oomycete and a major pathogen of grapevine. Studying obligate biotrophic pathogens is difficult as they cannot grow without their host. We therefore attempted to develop a method where the pathogen could be visualized and quantified in planta without killing the host plant. To this end P. viticola was transformed with the marker gene gfp coding for the green fluorescent protein. Various transformation methods, namely electroporation, particle bombardment and transformation with Agrobacterium tumefaciens were applied. Although some methods yielded positive transformation events, no stable strain of P. viticola expressing gfp could be generated. Using the electroporation method, we obtained transient P. viticola transformants expressing gfp over 4 generations. In contrast, particle bombardment failed in transforming P. viticola. Transformation with A. tumefaciens had a low efficiency, only some structures were fluorescent and fluorescence was never observed in the subsequent generations.

Screening for diabetes in optometry practices: acceptability to users

Purpose:  Diabetes is a leading cause of blindness in the working age population. While optometrists have an established role in screening people with known diabetes for eye disease, their role in screening for diabetes has not been evaluated. For diabetes screening in optometry practices to be successful it must be acceptable to both optometrists and to the public. The purpose of this study was to determine acceptability to people attending optometry practices of using random capillary blood glucose (rCBG) tests to detect raised blood glucose levels in optometry practices. Methods:  A screening service offering people with risk factors or symptoms of diabetes rCBG tests was piloted in five high street opticians’ practices in North East England. One thousand and two people used the screening service during a 20 week period. Each was given a questionnaire to complete and return following a rCBG test. Results:  Nine hundred and thirty-nine questionnaires were returned (return rate 93.7%). The mean age of participants was 54.5 years, 63.3% were female and 75.0% had not been screened for diabetes previously. 99.1% agreed or strongly agreed that the location was convenient for them and 98.0% would recommend others to use the screening service. 83.8% of the participants would not have gone elsewhere to have any tests done and 148 (16.2%) responded that they would have sought a test elsewhere; 14.2% at the GP, 0.8% at a pharmacy and 0.5% elsewhere. Only 3.2% reported that the test procedure was uncomfortable. Conclusions:  To those attending opticians’ practices, screening using rCBG tests is acceptable in terms of convenience and test comfort, and they would recommend the test to others. Screening in optometry practices provides an opportunity to identify people at risk of diabetes in a hitherto unutilised setting

Конституційні принципи як основа загальноєвропейських стандартів виборчого права

Кравчук В. Р. Конституційні принципи як основа загальноєвропейських стандартів виборчого права / В. Р. Кравчук // Міжнародні читання з міжнародного права пам’яті професора П.Є. Казанського : матер. третьої міжнар. наук. конф. (м. Одеса, 2–3 листопада 2012 р.) / відп. за випуск М. І. Пашковський ; НУ «ОЮА». – Одеса : Фенікс, 2012. – С. 161-164.На думку автора статті, дотримання п’яти принципів європейських стандартів виборчого права (загальне, рівне, вільне, пряме виборче право і таємне голосування) є необхідним для демократії. Це не означає, що виборче законодавство є сталим і незмінним. Навпаки, в межах цих принципів (та дотримання прав людини, без чого вони не можуть бути запроваджені) воно широко відкрите для обговорення і змін. Лише за умови дотримання цих принципів можна визнавати чинність різних виборчих систем та різних підходів до організації виборів