323 research outputs found

    Feedbacks in Non-equilibrium Oxidative Plasma Reacting with Polyethylene

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    The experimental results on studies of loading effect at the action of a glow DC discharge in oxygen and air on polyethylene film are presented. At the increase in a polymer amount under a treatment the specific rates of etching and CO2, CO, H2O, H2 product formation rates are decreased. The gas temperature is changed slightly. The reduced electric field strength is increased in oxygen plasma and decreased in air plasma

    Fast visible imaging of turbulent plasma in TORPEX

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    Fast framing cameras constitute an important recent diagnostic development aimed at monitoring light emission from magnetically confined plasmas, and are now commonly used to study turbulence in plasmas. In the TORPEX toroidal device [A. Fasoli et al., Phys. Plasmas 13, 055902 (2006)], low frequency electrostatic fluctuations associated with drift-interchange waves are routinely measured by means of extensive sets of Langmuir probes. A Photron Ultima APX-RS fast framing camera has recently been acquired to complement Langmuir probe measurements, which allows comparing statistical and spectral properties of visible light and electrostatic fluctuations. A direct imaging system has been developed, which allows viewing the light, emitted from microwave-produced plasmas tangentially and perpendicularly to the toroidal direction. The comparison of the probability density function, power spectral density, and autoconditional average of the camera data to those obtained using a multiple head electrostatic probe covering the plasma cross section shows reasonable agreement in the case of perpendicular view and in the plasma region where interchange modes dominate.This work is partly funded by the “Fonds National Suisse de la Recherche Scientifique.

    Mathematical modelling of the spatial network of bone implants obtained by 3D-prototyping

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    In this paper, the mathematical model suitable for bone implants 3D-prototyping is proposed. The composite material with the spatial configuration of reinforcement with matrix of hydroxyapatite and titanium alloys fibers is considered. An octahedral cell is chosen as an elementary volume. The distribution of reinforcing fibers is described by textural parameters. Textural parameters are integrated characteristics that summarize information on the direction of reinforcing fibers and their volume fractions. Textural parameters, properties of matrix and reinforcing fibers allow calculating effective physical and mechanical properties of the composite material. The impact of height and width of the octahedral reinforcement cells on textural parameters of the composite material is investigated in this work. The impact of radius of fibers is also analyzed. It is shown that the composite becomes quasi-isotropic under certain geometrical parameters of cell. © 2016 Author(s)

    Primjena frakcijske plinske analize za određivanje sadržaja oksidnih i dušičnih faza u ALNICO legurama

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    Fractional gas analysis procedure for estimating the contents of oxide and nitride inclusions in Alnico alloys produced from wastes of production is developed. The effect of the temperature and time of melt holding before pouring on the content of impurity oxide and nitride inclusions is considered. The content of SiO2 inclusions in Alnico mainly depends on the holding time before pouring and decreases with increasing holding time, whereas the content of Al2O3 inclusions decreases with increasing both temperature and time of holding. The content of TiN inclusions decreases with increasing holding time. As the holding temperature increases, the content of nitride inclusions decreases only with increasing holding time.Razrađena je metoda frakcijske plinske analize za vrednovanje oksidnih i dušičnih uključaka u ALNICO legurama, dobijenih iz gospodarskih otpada. Posmatran je utjecaj temperature i vremena zadržavanja kupke prije lijevanja. Sadržaj uključaka SiO2 uglavnom ovisi od vremena zadrške prije lijevanja i snižava se povećanjem tog vremena, istodobno se sadržaj uključaka Al2O3 smanjuje s povećavanjem i temperature i vremena zadrške. Sadržaj uključaka TiN smanjuje se povećavanjem vremena zadrške. S povećanjem temperature sadržaj dušičnih uključaka smanjuje se samo pri povećanju vremena zadrške prije lijevanja

    Tumor microenvironment: the formation of the immune profile

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    Tumor microenvironment (TME) is formed as a result of interaction and cross-linking between the tumor cell and different types of surrounding cells. Recent studies have shown that the tumor reprograms the microenvironment so that TME promotes the development of primary tumors, their metastasis and becomes an important regulator of oncogenesis. Under the influence of the tumor, the immune profile in the TME undergoes significant changes, “editing". An immunosuppressive network is formed, which suppresses the activity of the main effector of cellular immunity — T lymphocytes. T cells in TMA are in a state of anergy and exhaustion. T cells in TME are characterized by increased expression of inhibitory receptors, decreased secretion of cytokines and cytolytic activity. Blocking inhibitory receptors with specific antibodies can lead to the restoration of the functions of exausted T cells. Therefore, the restoration of the functional activity of T lymphocytes is one of the important strategies in cancer immunotherapy. The formation of the immune profile is influenced by genetic aberrations accumulating in the tumor. They play an important role in creating a specific, characteristic only for this tumor immune environment in the TME. Genetic changes in tumor cells lead to phenotypic and functional rearrangements of lymphocytes, which allows the tumor to escape the reaction of immune cells. Since many tumors occur after prolonged inflammation or exhibit characteristics of chronic inflammation as they progress, inflammation is considered an important factor in the formation of immune profile in TME. Immune infiltrates from different human tumors associated with inflammation may contain valuable prognostic and pathophysiological information. Macrophages in the TME now began to be regarded as descriptive marker and as a therapeutic target. One of the main mechanisms by which tumor cells reprogram surrounding cells is the release of exosomes — small vesicles that carry and deliver proteins and nucleic acids to other cells. When exosomal cargo is absorbed, molecular, transcriptional and translational changes occur in the recipient non-tumor cells in the TME. Therefore, tumor exosomes are an effective means by which the functions of immune cells in TME are purposefully changed. Thus, along with individual molecular and genomic testing of the tumor, attention should be paid to a deeper analysis of the immune profile of TME. It is a large resource of biomarkers and targets for immunotherapy

    Soft elasticity in biaxial smectic and smectic-C elastomers

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    Ideal (monodomain) smectic-AA elastomers crosslinked in the smectic-AA phase are simply uniaxial rubbers, provided deformations are small. From these materials smectic-CC elastomers are produced by a cooling through the smectic-AA to smectic-CC phase transition. At least in principle, biaxial smectic elastomers could also be produced via cooling from the smectic-AA to a biaxial smectic phase. These phase transitions, respectively from DhD_{\infty h} to C2hC_{2h} and from DhD_{\infty h} to D2hD_{2h} symmetry, spontaneously break the rotational symmetry in the smectic planes. We study the above transitions and the elasticity of the smectic-CC and biaxial phases in three different but related models: Landau-like phenomenological models as functions of the Cauchy--Saint-Laurent strain tensor for both the biaxial and the smectic-CC phases and a detailed model, including contributions from the elastic network, smectic layer compression, and smectic-CC tilt for the smectic-CC phase as a function of both strain and the cc-director. We show that the emergent phases exhibit soft elasticity characterized by the vanishing of certain elastic moduli. We analyze in some detail the role of spontaneous symmetry breaking as the origin of soft elasticity and we discuss different manifestations of softness like the absence of restoring forces under certain shears and extensional strains.Comment: 26 pages, 6 figure

    The MAST motional Stark effect diagnostic

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    A motional Stark effect (MSE) diagnostic is now installed and operating routinely on the MAST spherical tokamak, with 35 radial channels, spatial resolution of ∼2.5 cm, and time resolution of ∼1 ms at angular noise levels of ∼0.5°. Conventional (albeit very narrow) interference filters isolate π or σ polarized emission. Avalanche photodiode detectors with digital phase-sensitive detection measure the harmonics of a pair of photoelastic modulators operating at 20 and 23 kHz, and thus the polarization state. The π component is observed to be significantly stronger than σ, in reasonably good agreement with atomic physics calculations, and as a result, almost all channels are now operated on π. Trials with a wide filter that admits the entire Stark pattern (relying on the net polarization of the emission) have demonstrated performance almost as good as the conventional channels. MSE-constrained equilibrium reconstructions can readily be produced between pulses.This work was funded partly by the United Kingdom Engineering and Physical Sciences Research Council under Grant No. P/G003955 and by the European Communities under the contract of association between Euratom and CCFE

    BUILDING A TOMOGRAPHIC VELOCITY MODEL FOR SAMOYLOV ISLAND AREA (LENA DELTA) FROM LOCAL SEISMOLOGICAL DATA FOR THE PERIOD OF 2019–2021

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    In our paper we present the results of seismotomographic inversion for the local seismological monitoring data obtained in the area of the Samoylov Island (Lena River delta) in 2019–2021. Tomographic velocity model was used for refining hypocenter locations of local earthquakes and for geological interpretation. The results are shown as maps of anomalies of seismic waves and Vp /Vs ratios for the 5 and 10 km depths. The velocity anomalies structure made it possible to interpret low Vp /Vs ratio as rocks related to the Siberian platform, and to compare between the boundary of the low Vp /Vs area and the trace of the known geological fault running along the Olenekskaya Channel
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