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

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

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.)

Optical properties of the Ti surface structured by femtosecond laser beam

Wavelength-scaled periodic ripples formed on the Ti surface under the action of femtosecond laser irradiation have been investigated. The ripples were oriented in parallel to the incident light polarization. After initial formation of ripples, the following laser induced chemical transformation of metallic Ti into dielectric compound was established using the Raman scattering data. Weak Wood’s anomaly in the spectra on light diffracted by the structured Ti surface testifies the minor plasmonic activity

Effective anisotropy of thin nanomagnets: beyond the surface anisotropy approach

We study the effective anisotropy induced in thin nanomagnets by the nonlocal demagnetization field (dipole-dipole interaction). Assuming a magnetization independent of the thickness coordinate, we reduce the energy to an inhomogeneneous onsite anisotropy. Vortex solutions exist and are ground states for this model. We illustrate our approach for a disk and a square geometry. In particular, we obtain good agreement between spin-lattice simulations with this effective anisotropy and micromagnetic simulations.Comment: ReVTeX, 14 pages, 6 figure

Increased Sensitivity to Possible Muonium to Antimuonium Conversion

A new experimental search for muonium-antimuonium conversion was conducted at the Paul Scherrer Institute, Villigen, Switzerland. The preliminary analysis yielded one event fulfilling all required criteria at an expected background of 1.7(2) events due to accidental coincidences. An upper limit for the conversion probability in 0.1 T magnetic field is extracted as $8 \cdot 10^{-11}$ (90% CL).Comment: 2 figure

Magnetic Vortex Core Reversal by Excitation of Spin Waves

Micron-sized magnetic platelets in the flux closed vortex state are characterized by an in-plane curling magnetization and a nanometer-sized perpendicularly magnetized vortex core. Having the simplest non-trivial configuration, these objects are of general interest to micromagnetics and may offer new routes for spintronics applications. Essential progress in the understanding of nonlinear vortex dynamics was achieved when low-field core toggling by excitation of the gyrotropic eigenmode at sub-GHz frequencies was established. At frequencies more than an order of magnitude higher vortex state structures possess spin wave eigenmodes arising from the magneto-static interaction. Here we demonstrate experimentally that the unidirectional vortex core reversal process also occurs when such azimuthal modes are excited. These results are confirmed by micromagnetic simulations which clearly show the selection rules for this novel reversal mechanism. Our analysis reveals that for spin wave excitation the concept of a critical velocity as the switching condition has to be modified.Comment: Minor corrections and polishing of previous versio

Design, Commissioning and Performance of the PIBETA Detector at PSI

We describe the design, construction and performance of the PIBETA detector built for the precise measurement of the branching ratio of pion beta decay, pi+ -> pi0 e+ nu, at the Paul Scherrer Institute. The central part of the detector is a 240-module spherical pure CsI calorimeter covering 3*pi sr solid angle. The calorimeter is supplemented with an active collimator/beam degrader system, an active segmented plastic target, a pair of low-mass cylindrical wire chambers and a 20-element cylindrical plastic scintillator hodoscope. The whole detector system is housed inside a temperature-controlled lead brick enclosure which in turn is lined with cosmic muon plastic veto counters. Commissioning and calibration data were taken during two three-month beam periods in 1999/2000 with pi+ stopping rates between 1.3*E3 pi+/s and 1.3*E6 pi+/s. We examine the timing, energy and angular detector resolution for photons, positrons and protons in the energy range of 5-150 MeV, as well as the response of the detector to cosmic muons. We illustrate the detector signatures for the assorted rare pion and muon decays and their associated backgrounds.Comment: 117 pages, 48 Postscript figures, 5 tables, Elsevier LaTeX, submitted to Nucl. Instrum. Meth.