346 research outputs found
Supervising development in petroleum industry of the Russian Federation
Supervising has strongly consolidated in the domestic petroleum services market of the Russian Federation. But despite the rapid growth of the supervising services market, there is a definite need for its further development. In the article, the developments of supervising in petroleum industry of the Russian Federation, as well as possible ways of its improvement are considered
Enhanced Optical 13C Hyperpolarization in Diamond Treated by High-Temperature Rapid Thermal Annealing
Methods of optical dynamic nuclear polarization open the door to the replenishable hyperpolarization of nuclear spins, boosting their nuclear magnetic resonance/imaging signatures by orders of magnitude. Nanodiamond powder rich in negatively charged nitrogen vacancy defect centers has recently emerged as one such promising platform, wherein 13C nuclei can be hyperpolarized through the optically pumped defects completely at room temperature. Given the compelling possibility of relaying this 13C polarization to nuclei in external liquids, there is an urgent need for the engineered production of highly “hyperpolarizable” diamond particles. Here, a systematic study of various material dimensions affecting optical 13C hyperpolarization in diamond particles is reported on. It is discovered surprisingly that diamond annealing at elevated temperatures ∼1720 °C has remarkable effects on the hyperpolarization levels enhancing them by above an order of magnitude over materials annealed through conventional means. It is demonstrated these gains arise from a simultaneous improvement in NV− electron relaxation/coherence times, as well as the reduction of paramagnetic content, and an increase in 13C relaxation lifetimes. This work suggests methods for the guided materials production of fluorescent, 13C hyperpolarized, nanodiamonds and pathways for their use as multimodal (optical and magnetic resonance) imaging and hyperpolarization agents
Suppression of flow pulsation activity by relaxation process of additive effect on viscous media transport
The article presents the analysis of the processes occurring together with the turbulent transfer of impulse in mixture of hydrocarbon fluid and polymer solutions (anti-turbulent additives). The study evaluates complex shear flows by popular theoretical and practical methods. Understanding of hydrodynamic and dissipative effects of laminar-turbulent transition tightening and turbulence suppression is provided. The peculiarities of "thin" flow structure in pipeline zones with complex shape walls are evaluated. Recommendations to forecast the local flow parameters, calculation of hydraulic resistance are given
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High contrast dual-mode optical and 13C magnetic resonance imaging in diamond particles
Multichannel imaging -- the ability to acquire images of an object through
more than one imaging mode simultaneously -- has opened interesting new
perspectives in areas ranging from astronomy to medicine. Visible optics and
magnetic resonance imaging (MRI) offer complementary advantages of resolution,
speed and depth of penetration, and as such would be attractive in combination.
In this paper, we take first steps towards marrying together optical and MR
imaging in a class of biocompatible particulate materials constructed out of
diamond. The particles are endowed with a high density of quantum defects
(Nitrogen Vacancy centers) that under optical excitation fluoresce brightly in
the visible, but also concurrently electron spin polarize. This allows the
hyperpolarization of lattice 13C nuclei to make the particles over three-orders
of magnitude brighter than in conventional MRI. Dual-mode optical and MR
imaging permits immediate access to improvements in resolution and
signal-to-noise especially in scattering environments. We highlight additional
benefits in background-free imaging, demonstrating lock-in suppression by
factors of 2 and 5 in optical and MR domains respectively. Ultimate limits
could approach as much as two orders of magnitude in each domain. Finally,
leveraging the ability of optical and MR imaging to simultaneously probe
Fourier-reciprocal domains (real and k-space), we elucidate the ability to
employ hybrid sub-sampling in both conjugate spaces to vastly accelerate
dual-image acquisition, by as much as two orders of magnitude in practically
relevant sparse-imaging scenarios. This is accompanied by a reduction in
optical power by the same factor. Our work suggests interesting possibilities
for the simultaneous optical and low-field MR imaging of targeted diamond
nanoparticles
Financial Aspects of Technological Concept for Energy Efficiency Enhancement during Stripper Wells Development in Tomsk Region
The issue of operating costs cutting in terms of falling oil prices on the world market actualizes the challenge to find technological solutions to reduce electricity consumption during well operation. This is especially important for stripped-wells of small deposits in Tomsk region. The correlation analysis between the cost of oil production, electricity, heat and fuel consumption during the extraction of one ton of oil allowed the authors to focus on the financial aspect of such technological solutions like periodic well operation in the Shinginskoye field as well as to recommend the application of this method at the other fields in Tomsk region
Study of the electrodes length influence on the trajectories of water droplets dispersed in oil and affected by non-uniform electric field
The paper presents the results of numerical modelling of the processes accompanying movement of drop viscous media (water) in oil under the influence of exterior forces of the electric and dynamic nature. Systematic calculations of influence on the electric field heterogeneity drops, created by a symmetric and asymmetrical configuration of electrodes are carried out both in inter electrode and behind electrode areas taking into account a complex operation of dielectrophoresis forces, buoyancies and drag, as well as the variability of electrode sizes. The analysis of drop movement trajectories shows that the asymmetrical configuration of electrodes can be applied for an electro-coalescence intensification of water-in-oil emulsion. Correctness of calculations of the mathematical model and numerical methods are confirmed by good results if compared with the available data of the other authors
Atomistic Simulations of Nanotube Fracture
The fracture of carbon nanotubes is studied by atomistic simulations. The
fracture behavior is found to be almost independent of the separation energy
and to depend primarily on the inflection point in the interatomic potential.
The rangle of fracture strians compares well with experimental results, but
predicted range of fracture stresses is marketly higher than observed. Various
plausible small-scale defects do not suffice to bring the failure stresses into
agreement with available experimental results. As in the experiments, the
fracture of carbon nanotubes is predicted to be brittle. The results show
moderate dependence of fracture strength on chirality.Comment: 12 pages, PDF, submitted to Phy. Rev.
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CLSM method for the dynamic observation of pH change within polymer matrices for oral delivery
If acid-sensitive drugs or cells are administered orally, there is often a reduction in efficacy associated with gastric passage. Formulation into a polymer matrix is a potential method to improve their stability. The visualization of pH within these materials may help better understand the action of these polymer systems and allow comparison of different formulations. We herein describe the development of a novel confocal laser-scanning microscopy (CLSM) method for visualizing pH changes within polymer matrices and demonstrate its applicability to an enteric formulation based on chitosan-coated alginate gels. The system in question is first shown to protect an acid-sensitive bacterial strain to low pH, before being studied by our technique. Prior to this study, it has been claimed that protection by these materials is a result of buffering, but this has not been demonstrated. The visualization of pH within these matrices during exposure to a pH 2.0 simulated gastric solution showed an encroachment of acid from the periphery of the capsule, and a persistence of pHs above 2.0 within the matrix. This implies that the protective effect of the alginate-chitosan matrices is most likely due to a combination of buffering of acid as it enters the polymer matrix and the slowing of acid penetration
Surface functionalisation of nanodiamonds for human neural stem cell adhesion and proliferation.
Biological systems interact with nanostructured materials on a sub-cellular level. These interactions may govern cell behaviour and the precise control of a nanomaterial's structure and surface chemistry allow for a high degree of tunability to be achieved. Cells are surrounded by an extra-cellular matrix with nano-topographical properties. Diamond based materials, and specifically nanostructured diamond has attracted much attention due to its extreme electrical and mechanical properties, chemical inertness and biocompatibility. Here the interaction of nanodiamond monolayers with human Neural Stem Cells (hNSCs) has been investigated. The effect of altering surface functionalisation of nanodiamonds on hNSC adhesion and proliferation has shown that confluent cellular attachment occurs on oxygen terminated nanodiamonds (O-NDs), but not on hydrogen terminated nanodiamonds (H-NDs). Analysis of H and O-NDs by Atomic Force Microscopy, contact angle measurements and protein adsorption suggests that differences in topography, wettability, surface charge and protein adsorption of these surfaces may underlie the difference in cellular adhesion of hNSCs reported here
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