bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of the bias of measurement uncertainty estimates with significant non-linearity of a model equation
Authors: Zakharov I P , Neyezhmakov P I , Botsiura O A
Published: November 2019

The analysis of the nonlinear model equation is carried out. The nonlinear model equation in a Taylor series is expanded. It is shown that the bias in the estimation of the combined standard uncertainty by using the Law of Propagation of Uncertainty is due to the terms of the expansion of the second degree. To eliminate this bias, it is necessary to take into account the kurtosis of the input quantities distributions. A finite increments method for obtaining reliable estimates of the uncertainties contributions for nonlinear model equations is proposed. A practical example of calculation of comparison loss in microwave power meter calibration by various methods was considered. Estimate of the measurement uncertainty obtained with Law of Propagation of Uncertainty in this case has a bias. The result obtained with the finite increments method coincides with the results obtained using the Monte Carlo method.
Methods for quantitative evaluation of force and technique in competitive sport climbing
Authors: Pandurevic D , Sutor A , Hochradel K
Published: November 2019

Increasing media attention of and progress in competitive climbing demand for novel solution in sport analysis to accompany and contribute to the evolution of climbing. We present a holistic approach to acquire movements in sport climbing. Knowledge on force and corresponding body motion helps to understand technique, performance and might even lead to injury prevention during training. Our system allows detection of peaks in force on each climbing hand and foot hold while recording the associated body position and motion. To achieve this, we equipped each hold with a three-axis force sensor and combined this with a three-dimensional markerless motion capture system based on a depth camera. Existing methods to determine finger strength and other parameters such as temperature are employed to ensure comparable and repeatable results. In addition, pre-assesement of athletes will be used to evaluate inter- and intra-individual variability among athletes.
Comparison of experimental procedures of a method for continuous friction measurement in airport pavements
Authors: Martins L , Ribeiro A , Alves e Sousa J , Dimas H
Published: November 2019

This paper describes a comparison performed between two experimental procedures (with the Grip Tester and the Continuous Friction Measurement Equipment) of the fixed-slip method for longitudinal continuous friction measurement in airport pavements. The measurement framework is described, namely, the experimental testing and the related conformity assessment procedure supported by different friction thresholds. The experimental results of the comparison are presented (raw data, differences between friction estimates and corresponding experimental probability distributions) and its impact on the conformity assessment result is discussed. Conclusions are drawn based on the obtained difference dispersion, instrumental measurement uncertainties and expected difference between the two experimental procedures.
Elastography of vocal folds
Authors: Lamprecht R , Maghzinajafabadi M , Döllinger M , Semmler M , Sutor A
Published: November 2019

The diagnosis of changes in the structure of the vocal folds is an important clinical task. There is no approach available, which is capable of getting synchronous spatial and biomechanical properties of them. Whereas biomechanical changes, particularly the elasticity, are a good maker for malignant and benign conditions. To gain the elastic characteristics of the vocal folds we are proposing an endoscopic approach using ultrasound elastography.
TCal: Contribution to metrology for Industry 4.0
Authors: Andonov Sasho , Cundeva-Blajer Marija
Published: November 2019

Touchless Calibration (TCal) is introduced as a future development in calibration metrology. TCal is dealing mostly with decreasing the steps necessary to provide calibration traceability. Missing steps actually contribute to considerable decreasing of time and costs of calibration keeping the calibration traceability on high level. In the scope of Metrology for Industry 4.0, it could be one of the important improvements bringing increased effectiveness and efficiency for manufacturing industry. In this paper, the detailed explanation of overall process is provided.
Why metrology? Fair dealing and efficient markets for the United Nations’ Sustainable Development Goals
Authors: Fisher Jr W P , Pendrill L , Lips da Cruz A , Felin A
Published: November 2019

Why metrology? What special value does it offer to the design and use of sustainability impact metrics, and so to the realization of the United Nations Sustainable Development Goals? One answer in short, is, “For justice.” The balance scale is a universal symbol of fairness, development and equality. A second brief reply is, “For efficient markets.” Common currencies for the exchange of value are well known as a key factor in lowering transaction costs and supporting property rights, both essential to market formation. The repeatedly encountered dilemma, of course, is how to design, calibrate, and use measures of economic, environmental, human, and social value that lower costs and are just in more than name alone, serving some but not others. Longer answers justify metrological traceability to consensus unit standards as a key factor in realizing the SDGs by showing how it contributes to (a) the cultivation of shared meanings and improved communication; (b) the grounding of pragmatic expressions of verified trust; (c) making real, reproducible developmental trajectories visible and manageable; and (d) creating the multilevel systems of systems required for managing and governing complex, adaptive, self-organizing forms of social, political, legislative and economic life. A more complete answer to the question, “Why metrology?,” then focuses on how the SDGs’ diverse stakeholder interests may be most effectively fulfilled via collective actions facilitated on the basis of shared values.
Real-time spectral analysis using Prism Signal Processing
Authors: Henry Manus
Published: November 2019

The Prism is a new signal processing object which provides fully recursive FIR filtering i.e. the computational load is small and fixed irrespective of filter length. The Prism also has negligible design cost. These features are attractive to the next generation of Industry 4.0 sensors requiring low cost and flexible signal processing. Recent work has demonstrated how, using a few simple design rules, a chain of six Prisms can create narrowband filters with arbitrary central frequency and bandwidth, also with low design and computational cost. In this paper this technique is extended to provide spectral analysis of data, whereby a sequence of filters is applied to a data set to provide selective frequency analysis.
Method selection to evaluate measurement uncertainty in microflow applications
Authors: Sousa J A , Batista E , Pellegrino O , Ribeiro A S , Martins L L
Published: November 2019

Microflow applications are gaining increasing importance in medicine, and are indeed crucial in areas such as neonatology and oncology. However, in terms of uncertainty evaluation the very small levels of flow entail problems characterized by a “close to the physical limit” situation. The same happens in nanovolume applications. In these cases the Law of Propagation of Uncertainty framework (GUM) may not to be adequate, since the interval of coverage probability will, in some circumstances, contain negative values, which is physically difficult to explain. Monte Carlo methods may be a good alternative when there are not many negative readings in the application (limit-of-detection problem), but may also prove inadequate otherwise, since the required functional relationship of the model will produce a peak of values centred at the zero value, which is also not very credible to describe satisfactorily the real situation. In the latter, the application of a Bayesian method will be the better approach to deal with the evaluation of measurement uncertainties. The whole process of the revision of the international metrological standardization lies in this principle, of selecting the best method to tackle the particular problem in hand, and not to apply blind recipes to the evaluation of uncertainty in measurement, and there is a new EMPIR project focused on providing examples to BIPM documents to strengthen this concept.
A dual measurement and stimulating system to monitor and promote NNS
Authors: Pereira J M , Viegas V , Postolache O , Girão P S
Published: November 2019

The present paper presents a dual system that can be used to measure and to generate non-nutritive sucking (NNS) signals. The NNS measurement is based on a pressure sensor that is pneumatically connected to a silicone pacifier. By its turn, the NNS stimulator is based on a miniature pump and a miniature electro-valve that are operated by opposite phased signals to produce the pulsed pressure signal that is pneumatically applied to the silicone pacifier. The paper highlights some specific issues related with the calibration of the pneumatic signal measuring chain. Processing and wireless transmission capabilities are provided by a low-cost solution based on a microcontroller. Calibration and experimental results are also included in the paper.
Information measurement systems in the digital society
Authors: Malykhina G F , Vasilyev A N , Tarkhov D A
Published: November 2019

The transition to the next technological order requires robotics and automation in the industry. Managing such process of production is impossible without scenario modeling, forecasting and diagnostic of possible emergencies based on measurement information received from various sensors. The models used must be adequate to the real state of the object, and not to its project, on the basis of which it was designed and manufactured. Such models are called twin models of physical objects. The objective of the research is to obtain the approaches to the creation of information-measuring systems capable of processing large volumes of measurement information for implementing dynamically changing twin models of physical objects, and to carry out continuous training and adaptation to changing conditions. The proposed method allows continuous extraction of knowledge from the measurement information, accumulation knowledge about the object during its life. It was shown that hybrid models with physical and mathematical substantiation and capability of learning based on measurement data are the possible solution.
Measurement and compensation of electrostatic forces between conducting surfaces at distances in the micrometer range by means of PTB’s nanonewton force facility
Authors: Nesterov Vladimir
Published: November 2019

The measurement and compensation of electrostatic forces between conducting surfaces play a major role in various experiments, including measurements of the Newtonian constant of gravitation, measurements of the Casimir force, precision tests of general relativity in space, searches for hypothetical forces (fifth forces), gravity on elementary particles, heating in ion traps, and the physics of Rydberg atoms [1, 2]. Although the actual value of the contact potential was not of direct interest, it was necessary to eliminate it accurately in these experiments in order to avoid residual electrostatic forces that may limit the accuracy and precision of such experiments. We demonstrate how PTB’s nanonewton force facility [3, 4] can be used to accurately determine and compensate for the contact potential difference. To measure the contact potential difference as well as the distance between a force sensor and a measured object, a new three-voltage method was developed. A new method of adjusting the parallelism of the plates is also presented. The methods and the results of measuring the contact potential difference and the distance in vacuum are presented for a so-called plane-plane geometry and a ball-plane geometry. Measurements of the temporal and spatial variations of the contact potential difference were performed. Measurements were carried out at distances in the micrometer range between the metallic surfaces. A significant dependence of the contact potential difference on the distance between the conducting surfaces and on the time was found.
Application of artificial neural networks for fusion of data from radar and depth sensors applied for persons’ monitoring
Authors: Mazurek Paweł
Published: November 2019

The research reported in this paper is related to the fusion of measurement data from the impulse-radar sensors and infrared depth sensors applied in a system for unobtrusive monitoring of elderly persons. Three methods for data fusion, based on the artificial neural networks – one trained on real-world data, and two trained on synthetic data generated on the basis of two different models of the data – are compared with respect to their capacity of decreasing the uncertainty of position estimation in a series of experiments which involved the tracking of a moving person.
How to transform all multiple solutions of the Kemeny Ranking Problem into a single solution
Authors: Muravyov S V , Baranov P F , Emelyanova E Y
Published: November 2019

Preference aggregation as a problem of a single consensus ranking determination, using Kemeny rule, for m rankings, including ties, of n alternatives is considered in the paper. The Kemeny Ranking Problem (KRP) may have considerably more than one optimal solutions (strict orders or permutations of the alternatives) and, hence, special efforts to deal with this phenomenon are needed. In the paper, there is proposed an efficient formal rule for convolution of the N multiple optimal permutations, the output profile β(N, n), into an exact single final consensus ranking, which can include ties. The convolution rule is as follows: in the final consensus ranking, alternatives are arranged in ascending order of their rank sums (total ranks) calculated for the output profile β; some two alternatives are considered to be tolerant if they have the same rank sums in β. The equivalent convolution rule can be also applied as follows: in the final consensus ranking, alternatives are arranged in descending order of row sums (total scores) calculated for a tournament table built for β; some two alternatives are deemed to be tolerant if they have the same row sums. It is shown that, for any alternative, its total rank and total score are equal in sum to the output profile dimension N×n. The convolution rules are validated using Borda count.
The metrologically reasonable clustering of measurement results
Authors: Semenov K K , Bolschikov V A
Published: November 2019

This paper is dedicated to the metrological aspects of clustering procedure. It is shown that taking into account the information on uncertainty of the data to be clustered allows easily making reasonable decisions that are metrologically supported. The paper presents that the problems that are usually difficult to solve in practice of the clustering become simpler: the proposed approach allows determining the number of maximum recognizable clusters and thus protects from the unreasonable conclusions and allows performing the preconditioning of data to be clustered simpler.
Impact of enzymatic methods for glucose measurement on the performance of clinical laboratories in proficiency testing
Authors: José da Silva Jerônimo Diogo , Costa Monteiro Elisabeth
Published: November 2019

The present study compares performance scores obtained by clinical laboratories participating in Proficiency Testing schemes for measuring three concentration items of glucose in lyophilized serum, according to the analytical method employed (Oxidase-Peroxidase or Hexokinase-Dehydrogenase). Two distinct scoring criteria guided the evaluation: one based on the consensus value from the participants’ results; and another one that uses parameters exclusively based on the assigned value defined by the reference material. The results indicate that the measuring method employed in laboratory practice significantly affects the uniformity of PT participants’ outcomes. The larger dispersion of data provided by participants using the Oxidase-Peroxidase enzymatic method caused a higher index of evaluation’s inadequacies for this group when the laboratory performance score applies the consensus approach.
Readings correction and on-line monitoring of fluid level measuring channels at NPP
Authors: Kalashnikov A A
Published: November 2019

Presently the international program has gained momentum aimed at increasing the power of nuclear power plants (NPP) with WWER- and PWR-types reactors up to 107% and also at extending the automated process control system (APCS) repair intervals up to 18 months, which places higher requirements to the accuracy of measurements of NPP technological parameters. To enable the implementation of this program, an algorithm for processing the measurement signals has been designed that ensures high precision in readings correction of hydrostatic level sensors for all operating modes of technological equipment. Methods for correction of readings based on the developed algorithm have been implemented in Russian nuclear power industry. In addition to the correction of readings the algorithm also provides online monitoring to identify all possible defects of fluid level measuring channels including hidden defects that are not detected by existing facilities of NPP control system. The paper describes the algorithm and its application it to the tasks of readings correction and on-line monitoring of fluid level measuring channels at NPP. As result the article represents one of the first steps to methodological development of the correction reading and on-line monitoring to detection and minimization of hidden defect on NPP measuring channels of all thermotechnical parameters.
The light and the dark sides of the moon: possibilities of Industry 4.0 for early non-invasive diagnosis of pathology and health-risks
Authors: Vasilieva M V , Glukhova V A , Grednovskaya E V , Dydrov A A , Klebanov I I , Nikolaeva I A , Yu Nikolskaya K , Penner R V , Tseilikman V E
Published: November 2019

Industry 4.0 is an innovation infrastructure based on global digital connectivity to create smart plants and provide global automation in science and society. In Industry 4.0, the Internet of Things is used to collect big data from embedded sensors into live and inanimate objects. “The health calculator is positioned as a universal objective measure of human health, since it can be used not only in any disease, but also in preventive medicine, in particular, in examining astronauts and athletes and in life-risk occupations. However, even such a deeply thought-out software as health calculator requires its further development, that is, the transition to a second-generation device in which health is assessed from other methodological points of view. We have tried to summarize Industry 4.0 into medicine. We began to construct “Digital Twins” with the psychological “twins organisms”. In the future, this structure will serve as a bridge from psychology to psychopathology. To conclude, Industry 4.0 can bring to humanity unique opportunities in maintaining health and preventing diseases and at the same time engaging it in qualitatively new stressful situations. Therefore, now it is worthwhile to look for ways to increase human resistance to new versions of informational stress.
Gait rehabilitation monitor
Authors: Leite P , Postolache O , Dias Pereira J M , Postolache G
Published: November 2019

This paper presents a simple wearable, non-intrusive affordable mobile framework that allows remote patient monitoring during gait rehabilitation by doctors and physiotherapists. The system includes a set of 2 Shimmer3 9DoF Inertial Measurement Units (IMUs), an Android smartphone and a developed app for collecting, primary processing of data and for persistence of data in a remote PostgreSQL database, which is available in a remote server and where further data processing is performed. This framework provides gait features classifier by invoking an implemented REST API available in the remote server. Low computational load algorithms based on Euler angles and filtered signals were developed and used for the classification and identification of several gait disturbances. These algorithms include the alignment of IMUs sensors data by means of a common temporal reference as well as heel strike and stride detection algorithms. After segmentation of the remotely collected signals for gait strides identification relevant features were extracted to feed, train and test a classifier for prediction of gait abnormalities using supervised machine learning type and Extremely Randomized Trees method.
Measurement system based on virtual reference axis for evaluation form and location of surfaces and axes of rotary details
Authors: Diakov D , Radev Hr , Vassilev V , Nikolova H
Published: November 2019

The system for measurement and control of the form and location of the surfaces and axes of large scaled rotational parts by means of a virtual reference base is used, by using a self-orientation multistage gauge allowing exclusion of the radial run-out of axis of rotation when access to the face surfaces of the workpiece is difficult or impossible.
The status of and prospects for development of voltage quantum standards
Authors: Katkov Alexander
Published: November 2019

The state and tendencies of the development of voltage standards based on the Josephson effect are considered. The methods of electric voltage reproduction are presented both in the field of dc and ac voltage of arbitrary shape based on the values of fundamental physical constants in the new SI, and directions of improvement and expansion of the field of application are outlined.
Effect of collisionality on the microinstabilities in the Globus-M spherical tokamak
Authors: Kiselev E O , Bakharev N N , Bulanin V V , Gusev V K , Khromov N A , Kurskiev G S , Minaev V B , Miroshnikov I V , Patrov M I , Petrov A V , Petrov Yu V , Sakharov N V , Schegolev P B , Telnova A Yu , Tokarev V A , Tolstyakov S Yu , Tukhmeneva E A , Yashin A Yu
Published: November 2019

Simulations of the microtearing instability developing in plasma of the Globus-M spherical tokamak were performed using the GENE gyrokinetic code in the flux-tube linear approximation mode. Under the effect of the instability, the magnetic islands form on the scale of the ion Larmor radius, and the magnetic field fluctuations occur that generate electron heat fluxes. The ion heat fluxes as well as the fluxes associated with the electrostatic fluctuations are negligible. The maximum growth rate of the microtearing instability is reached at a collision frequency within the experimental range of the collision frequency variation, within which the B
T × τE ∝ ν*−0.4±0.1 scaling calculations were performed [1]. In similar calculations performed at the MAST tokamak, the growth rate decreases with decreasing collisionality in the entire range of the collision frequency variation, within which the B
T × τE ∝ ν*−0.82 scaling calculations were performed [2]. This can explain why the dependences of energy confinement time on the collision frequency obtained for the MAST&NSTX and the Globus-M tokamaks are different.
Analyses and structure integrity estimation of the Upper Vertical Neutron Camera
Authors: Smirnov A , Modestov V , Kirienko I , Lobachev A , Murtazin I , Kudryavtsev A , Filimokhina A , Nemtsev G , Ivantsivskiy M , Listopad A
Published: November 2019

Vertical Neutron Camera (VNC) is a multichannel neutron collimator intended to characterize the fusion plasma neutron source. The VNC diagnostics (together with the 55.B1 Radial Neutron Camera) will measure the time-resolved neutron emission profiles for both DD and DT ITER plasmas, providing evaluation of the fusion power density, α-source density, neutron and α-source emissivity profiles, ion temperature profile, fusion power, total neutron flux and others parameters. The VNC is composed of two fanshaped collimating structures (lower and upper) that are located at different positions of the ITER Vacuum Vessel (VV).

Structural integrity assessment of the preliminary design of the Upper Vertical Neutron Camera has been performed. The design was updated based on the analysis results and in order to meet other ITER requirements. The thermal, mechanical, electromagnetic and seismic loads and load combinations were calculated and analyzed for the updated design. This article is focused on the normal operation thermal analysis and electromagnetic analysis, as the design changes mostly affect the thermal and electromagnetic interfaces within the structure. The important results were obtained; the article shows the considerable improvement in the construction performance.
The mechanism of the onset of turbulent structures under the ion temperature gradient drift instability conditions
Authors: Karbushev D N , Khvesyuk V I , Chirkov A Y
Published: November 2019

A possible mechanism of the appearance of turbulent structures in plasma is considered as a result of the development of unstable ion temperature gradient (ITG) drift waves, both with and without a sheared flow. A description of several stages of the drift wave evolution is proposed. The condition for limiting the growth of the wave amplitude is discussed. A qualitative agreement of the results with the theoretical and experimental results of other authors is shown. The motion of particles in the wave and vortex structures is studied on the basis of the proposed mechanism and ideas of other authors.
Tests of tungsten divertor mock-ups with plasma and e-beam high-heat fluxes
Authors: Budaev V P , Dedov A V , Komov A T , Varava A N , Frik P G , Fedorovich S D , Giniyatulin R N , Makhankov A N , Litunovsky N V , Zakharenkov A V , Sviridov E V , Tupotilov I A , Chang B L H
Published: November 2019

The tungsten divertor mock-ups were tested with high-heat fluxes in the e-beam facility and in the plasma device. The water-cooled mock-ups are tested with the combination of plasma and e-beam loads: (1) thermocyclic tests with the highpower electron beam load ranging from 5 to 40 MW/m2 and then (2) tests in the PLM plasma device with stationary plasma loads of up to 5 MW/m2. Such two tests are performed together for the first time. They simulate the variable loads onto the divertor plates, which can occur in the ITER during stationary discharges with transient ELM events. The duration of helium plasma discharges in the PLM amounted to 200 minutes. The temperature of the test targets heating amounted to 1000°C and more.
Possibility of obtaining hot plasma during the breakdown of high-pressure gases in strong magnetic fields
Authors: Omarov O A , Omarova N O , Omarova P Kh , Aliverdiev A A
Published: November 2019

The hot plasma production during the high-pressure gas breakdown in the strong magnetic fields with a magnetic strength H of up 16·106 A/m was considered experimentally. The breakdown occured in a short gap as a result of interaction of the monoenergetic electron beam (ne
∼ 1018 m−3, energy is about several keVs) with dense plasma (n ∼ 6 · 1022 m−3). The breakdown leads to the formation of the magnetic trap (magnetic mirror), and the discharge plasma becomes heated due to the electron beam, electron cyclotron resonance, and Joule heating processes. The studies have shown that the use of the strong longitudinal magnetic fields results in an increase in the specific power, conductivity, and plasma temperature.
Magnetic trap formation during the breakdown of high pressure gases in strong magnetic fields
Authors: Omarov O A , Omarova N O , Omarova P Kh , Kurbanismailov V S
Published: November 2019

Formation of hot plasma in strong magnetic fields during the breakdown of high-pressure gases in short gaps was studied experimentally. The breakdown occurs as a result of interaction of monoenergetic electron beam with dense plasma (n ∼ 6·1022 m−3). As a result of the spark channel formation and its explosive expansion inside the gap, the magnetic field in the anode and cathode regions becomes more intense, while between the electrodes it becomes weaker due to the expansion of the channel plasma. Thus, the axially symmetrical magnetic-mirror-type system is formed, which is similar to the magnetic trap. Formation of this system leads to the reduction of energy losses accompanied by a simultaneous increase in the plasma thermal energy, that is, to a considerable increase in its conductivity and temperature.
Propagation of microwave surface-wave-sustained discharge in air
Authors: Zhukov V I , Karfidov D M , Sergeichev K F
Published: November 2019

The propagation dynamics of the gas microwave discharge front in a quartz tube filled with air is studied experimentally. The discharge is initiated and sustained by the dipolar mode (m = 1) of the propagating surface electromagnetic wave (SEW). The discharge front propagation regime was experimentally discovered, which is characterized by the arrest of propagation of the discharge front, the plasma decay and the subsequent resumption of the translational motion, but at a lower propagation velocity. The distributions of the SEW electric field and the integrated discharge luminosity along the plasma column are measured. The mean plasma density in the tube was estimated using data on the measured SEW wavelengths and the dispersion relation.
Parameters of plasma bunches generated in a long mirror trap under conditions of gyromagnetic autoresonance
Authors: Andreev V V , Novitsky A A , Umnov A M
Published: November 2019

Temporal evolution of the spectrum and intensity of bremsstrahlung generated by the plasma bunches formed in a symmetric long mirror trap under conditions of gyromagnetic autoresonance was studied experimentally in detail. Bremsstrahlung was detected by two identical detectors installed in the axial and radial directions with respect to the stationary magnetic field. The results show that the radiation is spatially inhomogeneous. The parameters of the spectra measured in the radial direction strongly depend on the amplitude of the pulsed magnetic field, while the spectra measured in the longitudinal direction are determined mainly by the ECR conditions in the phase of filling the trap with the primary plasma. The integrated intensities, obtained with allowance for the refined form factors of the generated bunches recorded using the high-speed photochronography, made it possible to determine the number of primary plasma particles trapped in the autoresonance mode.
Plasma technology for surface processing of the ruthenium pacemaker electrodes
Authors: Martynenko Yu V , Budaev V P
Published: November 2019

For pacemaker electrodes, the surface structure elements should be nanometer-sized in order to reduce the capacitive electrical resistance coupling of the electrode with the myocardium tissue. It is proposed to test several approaches. One of them is the creation of the “fuzz” nanostructure on the titanium surface accompanied by the subsequent ruthenium deposition onto this structure. Another one is the formation of the “fuzz” nanostructure on the layer of pre-deposited ruthenium. Such approaches contribute to developing new technology for manufacturing the electric cardiac pacemakers with improved characteristics.
Features of using plasma flows to compensate the aerodynamic drag of mini-satellites moving in the ionosphere
Authors: Nosachev L V , Skvortsov V V , Urusov A Yu , Uspenskii A A , Flaxman J Sh
Published: November 2019

The possibilities of using plasma flows formed in electric jet engines (EJE) are considered. One of the variants of the EJE construction are ion sources with multi-cell ion-optical systems used to compensate the aerodynamic drag of mini-satellites in the Earth’s ionosphere with the aim of ensuring long-term operation of the latter at low flight altitudes (∼180–220 km). The analysis of methods of simulation of the operation of such engines together with air intakes under ground conditions is given. The possibility of using plasma-ion sources producing molecular beams of nitrogen or air ions with low (orbital) flight speeds as a source of the free flow in the simulations is considered. A source with volumetric ionization of the working gas and electron oscillation in the magnetic field in a chamber between the walls held at the cathode potential and a large multi-cell aperture of the ion–optical system is used to create the flow. The results of the studies of the operation of a plasma–ion engine (PIE) together with air intake obtained by the gas-dynamic simulation method are presented. The possibility of a high performance of the engine under non-standard conditions is shown. It is found that a stable operation of the PIE can be realized at pressures of 6⋅10−5–10−4 Torr in its chamber, which is important for matching the engine with the air intake.
On the issue of quantum theory of the Fresnel reflection
Authors: Veklenko B A
Published: November 2019

A new method for solution of the quantum electrodynamics equations is proposed. This method makes it possible to avoid the procedure of breaking the quantum correlators and bridges the gap between the theories of Maxwell gases and the theories of superconductivity and superfluidity. As an example, the quantum theory of the Fresnel reflection is considered. It is shown that, even outside the scattering layer, there are the photon states correlated with the scattering layer by means of the quantum correlations. In particular, such photons form two reflected beams previously unknown.
Generation of fast electrons in pulsed discharge plasma in helium
Authors: Shibkov V. M
Published: November 2019

The results of experimental studies of the distribution function of fast electrons under conditions of non-equilibrium plasma of a pulsed discharge in helium are presented. It was established by various methods that at the initial stage of the discharge, when the reduced electric field exceeds the critical value, a beam of fast electrons is generated. The beam energy depends on the applied voltage to the discharge gap, and helium pressure.
Hypersonic plasma flows created by a pulse capillary discharge
Authors: Pashchina A S
Published: November 2019

The possibility of producing by a pulsed capillary discharge the quasi-stationary high-speed plasma flows in a wide range of Mach numbers (M=3-20), electron number densities (ne
∼1011-1015 cm-3) and temperatures (Te
∼3-10 eV), rotational and vibrational temperatures (Tr
=3800-6000 K and Tv
=9000-15000 K), which can be used for setting up plasma aerodynamic experiments on small laboratory facilities, is shown. The most suitable for this purpose is a mode close to supersonic outflow into a vacuum, the transition to which occurs when the total pressure ratio exceeds N = p
0/p
∞ >5·103. This mode permits to obtain wide-aperture flows (D >10 cm) with spatially extended weakly inhomogeneous segments sufficient to accommodate tested bodies of a centimeter scale.
Pulsed plasma jet interaction with a metal targets
Authors: Pashchina A S , Klimov A I , Belov N K , Tolkunov B N , Kh Timirbulatov V
Published: November 2019

The results of experimental studies of the interaction of plasma jets, created by a pulsed capillary discharge with an evaporating wall, with metal targets are presented. It is shown that the main mechanism of targets destruction is the material melting and the subsequent removal of the melt under the dynamic pressure of the plasma jet. The main sources of energy transmitted to the target are: the high-speed flow of high-enthalpy plasma created inside the capillary, and the fluxes of charged particles accelerated in the near-electrode layers. The energy transport provided by charged particles does not exceed ∼0.1–0.2 of the total energy input onto the target. The enthalpy transport is capable to provide heat flux densities of ∼5-6 kW/mm2, an order of magnitude exceeding the values achievable in welding arcs.
Determination of the fraction of electrical energy released in the oncoming supersonic airflow using long spark discharge
Authors: Saveliev A S
Published: November 2019

In present work an indirect measurement of the fraction of stored electrical energy, that by initiating long spark discharge of submicrosecond duration transforms into air heating, that moves near the surface of an aerodynamic model at supersonic speed with Mach number M = 2, was carried out. Using the Particle Image Velocimetry method the flow velocity behind the front of an induced quasi-cylindrical shock wave that occurs when heat is released with long spark discharge was measured. This process was modeled in a two-dimensional formulation using a numerical simulation with OpenFOAM package. By comparing the data obtained in the experiment and in the numerical simulation the value of the fraction of stored electrical energy, which goes to the local heating of air, was determined.
Impact of homogeneous and ionization unstable glow discharge plasma on a shock wave in air
Authors: Erofeev A.V. , Lapushkina T.A. , Azarova O.A.
Published: November 2019

The work is aimed at exploring the possibility of control of strong shock waves up to their completely destruction. The impact on shock waves by creating a region of gas-discharge plasma in propagation media is proposed. A diffuse or ionization unstable discharge with the ionization strata of different scale on the path of a shock wave propagation is organized. As a result, the shock wave propagates over the region of homogeneous highly non-equilibrium plasma or over the medium of layered structure with higher degree of ionization and electron temperature in the layers. Numerical simulation of the propagation of a shock wave over the region of energy impact was carried out on the basis of the systems of Euler and Navier-Stokes equations with the flow parameters obtained in the experiment. The homogeneous plasma region was simulated by a rarefied gas region with increased temperature and constant pressure. The area formed by the ionization unstable discharge was simulated by a thermally stratified gas area. The strong influence of the ionization of the propagation medium on the transformation of the shock wave with the formation of a new shock wave configuration is shown. Stratification of the medium leads to a distortion of this configuration up to complete destruction of it.
Nanosecond volume discharge in the flow with diffracting shock wave in the rectangular channel
Authors: Znamenskaya I , Tatarenkova D , Kuli-zade T
Published: November 2019

New effects of plasma redistribution shock wave (M = 2.8–3.4) diffraction on an obstacle at flow ionization with pulse volume discharge are presented. The obstacle has size 48.0 × 6.2x1.9 mm3 and consist of forward facing and backward facing steps on the wall. Localization of the nanosecond combined discharge plasma (with pre-ionization in the volume) in non-stationary gas flow was visualized with plasma glow imaging. It is shown that the discharge images visualize flow evolution structure, mainly - zones of reduced density. Image are compared with 2D CFD simulation.
Numerical simulations on MHD break in hypersonic flow
Authors: Bityurin V.A. , Bocharov A.N. , Popov N.A.
Published: November 2019

One of possible effect of electromagnetic field on the high-speed ionized airflow is considered. Namely, deceleration of the flying body due to interaction of the electric current induced around the body with the magnetic field generated by on-board magnetic system is studied. The principal scheme of magnetohydrodynamic interaction over the flat plate is presented. The goal of the study is to demonstrate the deceleration effect in terms of standard aerodynamic drag. Two test cases are considered: small-scale (lab-scale) interaction zone size and large-scale (space-scale) one.

The primary result of the study is a feasibility to increase the total drag of the body in more than order of magnitude relative to the original one. The effect can be achieved by means of practically reasonable magnetic field amplitudes. Common for both cases is that the total drag grows as the magnetic field increases. The difference between two cases is that significantly smaller magnetic fields are required in space-scale case to increase aerodynamic drag than in the lab-scale case. In any case, the drag control could be used as a potential for high-speed flow control.
Early transformation of the Chinese power sector to avoid additional coal lock-in
Authors: Wang Huan , Chen Wenying , Bertram Christoph , Malik Aman , Kriegler Elmar , Luderer Gunnar , Després Jacques , Jiang Kejun , Krey Volker
Published: November 2019

Emission reduction from the coal-dominated power sector is vital for achieving China’s carbon mitigation targets. Although the coal expansion has been slowed down due to the cancellation of and delay in new construction, coal-based power was responsible for over one third of China’s energy-related CO2 emissions by 2018. Moreover, with a technical lifetime of over 30 years, current investment in coal-based power could hinder CO2 mitigation until 2050. Therefore, it is important to examine whether the current coal-based power planning aligns with the long-term climate targets. This paper introduces China’s Nationally Determined Contribution (NDC) goals and an ambitious carbon budget along with global pathways well-below 2 degrees that are divided into five integrated assessment models, which are two national and three global models. We compare the models’ results with bottom-up data on current capacity additions and expansion plans to examine if the NDC targets are in line with 2-degree pathways. The key findings are: 1. NDC goals alone are unlikely to lead to significant reductions in coal-based power generation. On the contrary, more plants may be built before 2030; 2. this would require an average of 187–261 TWh of annual coal-based power capacity reduction between 2030 and 2050 to achieve a 2 °C compatible trajectory, which would lead to the stranding of large-scale coal-based power plants; 3. if the reduction in coal power can be brought forward to 2020, the average annual coal-based power reduction required would be 104–155 TWh from 2020 to 2050 and the emissions could peak earlier; 4. early regulations in coal-based power would require accelerated promotion of alternatives between 2020 and 2030, with nuclear, wind and solar power expected to be the most promising alternatives. By presenting the stranding risk and viability of alternatives, we suggest that both the government and enterprises should remain cautious about making new investment in coal-based power sector.
Evidence for accelerated weathering and sulfate export in high alpine environments
Authors: Crawford John T , Hinckley Eve-Lyn S , Litaor M Iggy , Brahney Janice , Neff Jason C
Published: November 2019

High elevation alpine ecosystems—the ‘water towers of the world’—provide water for human populations around the globe. Active geomorphic features such as glaciers and permafrost leave alpine ecosystems susceptible to changes in climate which could also lead to changing biogeochemistry and water quality. Here, we synthesize recent changes in high-elevation stream chemistry from multiple sites that demonstrate a consistent and widespread pattern of increasing sulfate and base cation concentrations or fluxes. This trend has occurred over the past 30 years and is consistent across multiple sites in the Rocky Mountains of the United States, western Canada, the European Alps, the Icelandic Shield, and the Himalayas in Asia. To better understand these recent changes and to examine the potential causes of increased sulfur and base cation concentrations in surface waters, we present a synthesis of global records as well as a high resolution 33 year record of atmospheric deposition and river export data from a long-term ecological research site in Colorado, USA. We evaluate which factors may be driving global shifts in stream chemistry including atmospheric deposition trends and broad climatic patterns. Our analysis suggests that recent changes in climate may be stimulating changes to hydrology and/or geomorphic processes, which in turn lead to accelerated weathering of bedrock. This cascade of effects has broad implications for the chemistry and quality of important surface water resources.
Research on discrimination algorithm of electric energy substitution user based on logistic regression model
Authors: Chen Jihuan , Lu Yudong , Liu Qiang , Li Lei , Miao Bo
Published: November 2019

The current power grid is found with low visiting efficiency, information integration difficulty and other problems in case of promotion of electric energy substitution. The big data technology is featured by high efficiency, high speed and convenience in terms of information processing, so it can realize the precise localization and differentiated marketing objectives of each enterprise. This paper, based on the analysis of energy consumption status of current power grid user and by means of “industry-field-user” architectural analysis, classifies user as per industry and equipment characteristics and combines with existing data of current power grid to exploit the energy consumption and electricity use characteristics of electric energy substitution user and build discrimination model of electric energy substitution user so as to improve the working efficiency and economic benefit of power grid business.
Research and Application of Prussian Blue in Modern Science
Authors: Chiang Yen-Hsin
Published: November 2019

Recently, the attention to Prussian Blue has been aroused in the next generation applications in many areas, due to its specific advantages. However, the development of Prussian blue remains significant challenges. For example, nowadays, it can effectively improve the electrochemical performance of ions batteries. Herein, we summarize the recent advances and applications materials on the progress of the study and application of Prussian Blue in several area, including storage, electrochemistry, photochemical, medical. Special attentions were given on the following items: Prussian Blue Sensor, Ionic batteries and Hydrogen storage. The superior chemical nature of Prussian Blue makes Prussian Blue important in many areas.
Systematic Study on Hydraulic Cylinder of Farmland DTH Drilling Machine
Authors: Chen Yiwei , Ma Yongshuang , Zhang Xiaolei
Published: November 2019

Connecting and unloading rod is one of the important processes in the drilling process of DTH drilling rig. The unloading device not only affects the operator’s labor intensity and safety, but also affects the efficiency of drilling rig and the service life of drilling rod. Therefore, the research and design of unloading rod structure is of great significance to improve the efficiency of DTH drilling rig. Firstly, the selection of unloading rod hydraulic cylinder is analyzed, including the calculation of main parameters, cylinder design, piston design and calculation, cushioning and exhaust device. Secondly, the clamp rod hydraulic cylinder is designed and calculated, including the structure of the clamp rod cylinder, the clamp force calculation of the clamp rod cylinder and the wall thickness calculation of the clamp rod cylinder. Finally, we set the structure and parameters correctly to increase the efficiency of the hydraulic cylinder of the down-the-hole drill in the field operation.
Research on Parallel Control Strategy of Virtual Synchronous Generators with same capacity
Authors: Wang Yanan , Yan Pengbo
Published: November 2019

In view of the public AC bus’s frequency stability problem of traditional droop control parallel inverters when load fluctuate frequently, virtual synchronous generator, VSG, is presented in this paper to instead traditional droop control in inverters parallel. The frequency stability of the public AC bus is improved and the output power is divided equally. In view of the VSG parallel preliminary synchronization, a preliminary synchronization method is designed based on phase-locked loop to realize the same phase between the VSG output voltage and public AC bus before paralleling. The simulation and experimental results verify the effectiveness of the proposed control strategy.