АNALYSIS OF OPTICAL METHODS FOR MONITORING THE WORKING SURFACE STATE OF THE GRINDING WHEEL

The article describes an analysis of non-contact optical methods for monitoring linear wear and the working surface condition of the grinding wheel during dry grinding. The presented methods are based on computer processing of photo and video materials, 3D models surface construction of the grinding wheel, the machine vision and using of the optical equipment. The advantages and disadvantages of this methods were analyzed. As a result of the conducted research, it was concluded that the usable area of the considered methods depends on the circle material, cutting parameters, control objectives, including the requirement for on-line control, and also the available material and technical equipment

A novel conceptual model of heart rate autonomic modulation based on a small-world modular structure of the sinoatrial node

The present view on heartbeat initiation is that a primary pacemaker cell or a group of cells in the sinoatrial node (SAN) center paces the rest of the SAN and the atria. However, recent high-resolution imaging studies show a more complex paradigm of SAN function that emerges from heterogeneous signaling, mimicking brain cytoarchitecture and function. Here, we developed and tested a new conceptual numerical model of SAN organized similarly to brain networks featuring a modular structure with small-world topology. In our model, a lower rate module leads action potential (AP) firing in the basal state and during parasympathetic stimulation, whereas a higher rate module leads during β-adrenergic stimulation. Such a system reproduces the respective shift of the leading pacemaker site observed experimentally and a wide range of rate modulation and robust function while conserving energy. Since experimental studies found functional modules at different scales, from a few cells up to the highest scale of the superior and inferior SAN, the SAN appears to feature hierarchical modularity, i.e., within each module, there is a set of sub-modules, like in the brain, exhibiting greater robustness, adaptivity, and evolvability of network function. In this perspective, our model offers a new mainframe for interpreting new data on heterogeneous signaling in the SAN at different scales, providing new insights into cardiac pacemaker function and SAN-related cardiac arrhythmias in aging and disease

The potential of retrofitting existing coal power plants: a case study for operation with green iron

Storing electrical energy for long periods and transporting it over long distances is an essential task of the necessary transition to a CO$_2$-free energy economy. An oxidation-reduction cycle based on iron and its oxides represents a very promising technology in this regard. The present work assesses the potential of converting an existing modern coal-fired power plant to operation with iron. For this purpose, a systematic retrofit study is carried out, employing a model that balances all material and energy fluxes in a state-of-the-art coal-fired power plant. Particular attention is given to components of the burner system and the system$'$s heat exchanger. The analysis provides evidence that main components such as the steam generator and steam cycle can be reused with moderate modifications. Major modifications are related to the larger amounts of solids produced during iron combustion, for instance in the particle feeding and removal systems. Since the high particle densities and lower demand for auxiliary systems improve the heat transfer, the net efficiencies of iron operation can be one to two percentage points better than coal operation, depending on operating conditions. This new insight can significantly accelerate the introduction of this innovative technology by guiding future research and the development of the retrofit option.Comment: Applied Energy Journa

Compound-tunable embedding potential method to model local electronic excitations on ff-element ions in solids: Pilot relativistic coupled cluster study of Ce and Th impurities in yttrium orthophosphate, YPO4_4

A method to simulate local properties and processes in crystals with impurities via constructing cluster models within the frame of the compound-tunable embedding potential (CTEP) and highly-accurate {\it ab initio} relativistic molecular-type electronic structure calculations is developed and applied to the Ce and Th-doped yttrium orthophosphate crystals, YPO$_4$, having xenotime structure. Two embedded cluster models are considered, the "minimal" one, YO$_8$@CTEP$_{\rm min}$, consisting of the central Y$^{3+}$ cation and its first coordination sphere of eight O$^{2-}$ anions (i.~e.\ with broken P--O bonds), and its extended counterpart, Y(PO$_4$)$_6$@CTEP$_{\rm ext}$, implying the full treatment of all atoms of the PO$_4^{3-}$ anions nearest to the central Y$^{3+}$ cation. CTEP$_{\rm min,ext}$ denote here the corresponding cluster environment described within the CTEP method. The relativistic Fock-space coupled cluster (FS RCC) theory is applied to the minimal cluster model to study electronic excitations localized on Ce$^{3+}$ and Th$^{3+}$ impurity ions. Calculated transition energies for the cerium-doped xenotime are in a good agreement with the available experimental data (mean absolute deviation of ca.0.3 eV for $4f{\to}5d$ type transitions). For the thorium-doped crystal the picture of electronic states is predicted to be quite complicated, the ground state is expected to be of the $6d$ character. The uncertainty for the excitation energies of thorium-doped xenotime is estimated to be within 0.35 eV. Radiative lifetimes of excited states are calculated at the FS RCC level for both doped crystals. The calculated lifetime of the lowest $5d$ state of Ce$^{3+}$ differs from the experimentally measured one by no more than twice

Pharmacological sequestration of mitochondrial calcium uptake protects against dementia and β-amyloid neurotoxicity

All forms of dementia including Alzheimer's disease are currently incurable. Mitochondrial dysfunction and calcium alterations are shown to be involved in the mechanism of neurodegeneration in Alzheimer's disease. Previously we have described the ability of compound Tg-2112x to protect neurons via sequestration of mitochondrial calcium uptake and we suggest that it can also be protective against neurodegeneration and development of dementia. Using primary co-culture neurons and astrocytes we studied the effect of Tg-2112x and its derivative Tg-2113x on β-amyloid-induced changes in calcium signal, mitochondrial membrane potential, mitochondrial calcium, and cell death. We have found that both compounds had no effect on β-amyloid or acetylcholine-induced calcium changes in the cytosol although Tg2113x, but not Tg2112x reduced glutamate-induced calcium signal. Both compounds were able to reduce mitochondrial calcium uptake and protected cells against β-amyloid-induced mitochondrial depolarization and cell death. Behavioral effects of Tg-2113x on learning and memory in fear conditioning were also studied in 3 mouse models of neurodegeneration: aged (16-month-old) C57Bl/6j mice, scopolamine-induced amnesia (3-month-old mice), and 9-month-old 5xFAD mice. It was found that Tg-2113x prevented age-, scopolamine- and cerebral amyloidosis-induced decrease in fear conditioning. In addition, Tg-2113x restored fear extinction of aged mice. Thus, reduction of the mitochondrial calcium uptake protects neurons and astrocytes against β-amyloid-induced cell death and contributes to protection against dementia of different ethology. These compounds could be used as background for the developing of a novel generation of disease-modifying neuroprotective agents

СКАНИРУЮЩАЯ ТОРОИДАЛЬНО-БИФОКАЛЬНАЯ ЛИНЗОВАЯ АНТЕННАЯ СИСТЕМА ДИАПАЗОНА 57–64 ГГЦ

Introduction. Currently, one of the most promising approaches to the development of 5th generation mobile wireless systems is the deployment of heterogeneous networks based on existing LTE cellular systems having both large and small cells. Small, low-cost relay stations equipped with highly directional steerable antenna systems to connect small cells with LTE base station serving macrocell can comprise the main elements of such networks. Objective. Since existing solutions are either too expensive or do not allow the flexible rearrangement of current information transmission lines, the objective of this work is to develop antenna equipment for low-cost relay stations based on simple, steerable antenna systems of millimetre wavelength (57-64 GHz), which allow beamsteering on both azimuth and elevation planes. Methods and materials. The developed steerable, bifocal lens antenna system comprises a specially-shaped lens made of high-molecular-weight polyethylene and integrated with a phased array antenna. A key feature of its design is a wide-angle beamsteering in the azimuth plane and ability to adjust the beam in the elevation plane. The calculation of the lens profiles was carried out by means of an approximation of geometrical optics in Matlab, while the main technical characteristics of the lens antenna system were obtained by direct electromagnetic modelling in CST Microwave Studio. Results. A prototype steerable, bifocal lens-array antenna system has been developed and its characteristics studied. The following technical characteristics are achieved in the 57–64 GHz range: beamsteering in the elevation plane – ±3º; beam-steering in the azimuth plane – ±40º; antenna gain – from 20 to 27.5 dBi for all angles. Conclusion. It is shown that the developed antenna system can be successfully used as a component of the receiving and transmission equipment of small relay stations that transmit information in the frequency range of 57-64 GHz over a distance of 100-300 m.Введение. В настоящее время одним из перспективных подходов к построению систем мобильной радиосвязи пятого поколения является развертывание неоднородных сетей на основе существующих систем сотовой связи LTE с большими и малыми сотами. Основными элементами таких сетей могут стать небольшие дешевые релейные станции, оснащенные высоконаправленными сканирующими антенными системами для связи малых сот с базовой станцией LTE, обслуживающей макросоту. Существующие решения во многом слишком дороги или не позволяют гибко перестраивать используемые линии передачи информации. Цель работы. Разработка антенного оборудования для дешевых релейных станций на основе простых сканирующих антенных систем миллиметрового диапазона длин волн (57…64 ГГц), позволяющих управлять главным лучом в двух плоскостях: азимутальной и угломестной. Материалы и методы. Профиль линзы из высокомолекулярного полиэтилена был рассчитан в приближении геометрической оптики в MATLAB. Основные технические характеристики линзовой антенной системы получены прямым электромагнитным моделированием в CST Microwave Studio, а также в ходе экспериментальных исследований с помощью вспомогательной антенны с высоким коэффициентом усиления, расположенной в дальней зоне. Результаты. Разработан и создан прототип сканирующей бифокальной линзовой антенной системы, представляющий собой линзу специальной формы из высокомолекулярного полиэтилена, интегрированную с плоской фазированной антенной решеткой. В диапазоне рабочих частот 57…64 ГГц достигнуты следующие технические показатели: углы сканирования в угломестной плоскости ±3º, в азимутальной плоскости ±40º, коэффициент усиления антенной системы для всех углов сканирования находится в пределах 20…27.5 дБи. Заключение. Разработанная линзовая антенная система может найти практическое применение в качестве приемо-передающего антенного оборудования небольших релейных станций, осуществляющих передачу информации в частотном диапазоне 57…64 ГГц на расстояния 100…300 м

Model-independent evidence for J/ψpJ/\psi p contributions to Λb0→J/ψpK−\Lambda_b^0\to J/\psi p K^- decays

The data sample of $\Lambda_b^0\to J/\psi p K^-$ decays acquired with the LHCb detector from 7 and 8~TeV $pp$ collisions, corresponding to an integrated luminosity of 3 fb$^{-1}$, is inspected for the presence of $J/\psi p$ or $J/\psi K^-$ contributions with minimal assumptions about $K^- p$ contributions. It is demonstrated at more than 9 standard deviations that $\Lambda_b^0\to J/\psi p K^-$ decays cannot be described with $K^- p$ contributions alone, and that $J/\psi p$ contributions play a dominant role in this incompatibility. These model-independent results support the previously obtained model-dependent evidence for $P_c^+\to J/\psi p$ charmonium-pentaquark states in the same data sample.Comment: 21 pages, 12 figures (including the supplemental section added at the end

Study of Bc+B_c^+ decays to the K+K−π+K^+K^-\pi^+ final state and evidence for the decay Bc+→χc0π+B_c^+\to\chi_{c0}\pi^+

A study of $B_c^+\to K^+K^-\pi^+$ decays is performed for the first time using data corresponding to an integrated luminosity of 3.0 $\mathrm{fb}^{-1}$ collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies of $7$ and $8$ TeV. Evidence for the decay $B_c^+\to\chi_{c0}(\to K^+K^-)\pi^+$ is reported with a significance of 4.0 standard deviations, resulting in the measurement of $\frac{\sigma(B_c^+)}{\sigma(B^+)}\times\mathcal{B}(B_c^+\to\chi_{c0}\pi^+)$ to be $(9.8^{+3.4}_{-3.0}(\mathrm{stat})\pm 0.8(\mathrm{syst}))\times 10^{-6}$. Here $\mathcal{B}$ denotes a branching fraction while $\sigma(B_c^+)$ and $\sigma(B^+)$ are the production cross-sections for $B_c^+$ and $B^+$ mesons. An indication of $\bar b c$ weak annihilation is found for the region $m(K^-\pi^+)<1.834\mathrm{\,Ge\kern -0.1em V\!/}c^2$, with a significance of 2.4 standard deviations.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-022.html, link to supplemental material inserted in the reference