bluuebunny/crossref_metadata_2025 huggingface dataset:
The effective modes of infrared radiators and heating systems
Authors: Ptitsyna Elena , Kuvaldin Alexander , Ptitsyn Dmitry
Published: December 2019

The authors have been researching the effect of polyharmonic currents (complex waveform current) on the characteristics of different types of radiators for a few years. These researches have shown an increase in the energy efficiency of installations with dark and light radiators and the ability to control the harmonic composition of radiation. It is important considering the need to harmonize the frequency characteristics of a radiator with the frequency response of an energy absorbing surface. The object of experimental research are flexible heating tape and installations with dark radiators and their joint operation modes when powered by complex waveform current from a common power source. The purpose of the work is the definition of characteristics of the flexible heating tape and dark infrared radiators when changing the amplitude and frequency of the supply voltage to develop recommendations for the selection of effective modes.
Simulation of gas-dynamic characteristics of a centrifugal compressor vane diffuser using neural networks
Authors: Nikiforov Aleksandr , Kuchumov Alexei , Terentev Sergei , Petukhov Evgeniy , Kabalyk Kirill
Published: December 2019

The paper presents the results of mathematical simulation of the characteristics of a vane diffuser of a centrifugal compressor intermediate stage, such as the loss coefficient and the deviation angle versus the outlet vane angle of the diffuser. The simulation of these characteristics was made on the basis of processing the results of studies performed by the Research Laboratory “Gas Dynamics of Turbomachines” of Peter the Great St.Petersburg Polytechnic University at the model characteristics of vane diffusers. Given the almost complete absence of recommendations in the literature, the paper describes the technology for constructing neural network models, which includes preparing a sample of input data and determining the optimal structure of the neural network. Based on the obtained mathematical models, a computational experiment was carried out in order to determine the influence of the main geometric and gas-dynamic parameters on the efficiency of vane diffusers. The results of the computational experiment on neural models of the efficiency of a vane diffuser are analyzed according to the existing ideas about the physics of the processes of energy conversion in a vane diffuser.
Improving the reliability of the compressor unit using the wavelet transform method
Authors: Lebedev A.A. , Aksenov A.A. , Lebedeva S.M. , Petrov A. Yu. , Nguyen Minh Hai
Published: December 2019

Centrifugal compressors are an integral part of modern production in such industries as gas transmission, oil refining, metallurgical, machine-building, mining, as well as in electric and heat power engineering. Interruptions in the operation or failures of compressors lead to decrease in profit or large material loss. Conditions should be created for the safe (stable) operation of centrifugal compressors. Surge is global (complete) loss of stability, an unacceptable phenomenon for a centrifugal compressor. Compressor surge protection must function during operation. The algorithms used to protect centrifugal compressors against surge have some drawbacks, which makes it impossible to reliably prevent surges. There are many methods for analyzing rapidly changing processes in the flow part of a centrifugal compressor. The wavelet theory is the most accurate and modern method. The use of the wavelet transform method for signal processing allows us to solve the problems of analyzing non-stationary processes of a centrifugal compressor to expand the acceptable range of work and build reliable operation of the anti-surge diagnostic system. In the future, it is possible to use other basic wavelet functions, for comparison and selection of the most suitable one, for the analysis of unsteady signals in a centrifugal compressor.
Head Math Model For The Low-Flow Impellers Of The Centrifugal Compressors
Authors: Ivanov Vyacheslav , Kozhukhov Yuri , Nguyen Minh Hai
Published: December 2019

A new mathematical model has been developed to determine the coefficient of internal and theoretical head in the variant design of the low-flow rate centrifugal compressors impellers. A parametric study of the flow part of the impeller is carried out. In total 1620 impellers are numericaly simulated. As a result, a numerical database of gas dynamic and geometric parameters was developed. Due to an a priori analysis, the relations of parameters with the geometric shape of the flow part are determined. The mathematical model is developed using gas-dynamic parameters and relations determined from numerical database. Using centrifugal compressor stage digital twins, a generalizing relationship has been developed to determine the complex of friction and leakage losses.The reliability of the math model is validated by the comparison with experimental data and the results of numerical experiment in digital twins, which are not involved in the model. The application of the head math model is determined in the range of the conditional flow coefficient 0.006<Φd<0.02 and the theoretical head coefficient 0.60 <ψt<0.72.
Numerical investigation of a moisture wave-type vane separator
Authors: Kasatkin Ivan , Egorov Mikle , Rakov Nikolay
Published: December 2019

This study aims to determine the appropriate method for modeling separation processes in wave-type moisture vane separators and to analyze possible design improvements of the typical wave-type vane separator using numerical simulation methods. It discusses conditions of the secondary droplets generation phenomena. The applicability of the particle transport method for modeling the working process in wave-type vane separators is confirmed. The study explores the water droplets distribution pattern in the dispersed two-phase flow of a separator. A numerical study of the workflow in the typical steam-water separator with wave-type vanes was carried out. A dispersed two-phase flow in a separator is modelled as two separate flows. Dry saturated steam is considered as a continuous medium using the Euler method; the liquid phase is represented as a stream of water droplets described by the Lagrange method. Authors propose an option of modernization of the separator design applying three drainage channels on the path of small droplets.
Optimization of calculations of the effects of spill fires during accidents on linear equipment
Authors: Saltanaeva Elena Andreevna , Maister Andrey Vladimirovich
Published: December 2019

The issue of industrial (in particular, fire) safety at hazardous production facilities is considered. The previously obtained optimization method is given for calculating the assessment of the influence of hazardous factors in the event of possible accidents on extended (linear) equipment during explosions of fuel-air mixtures. Optimization is based on accelerating the calculations of the potential damage probability of Qn(M0) using transformed formulas containing a single instead of a double integral. The transformed formulas for calculating the double integral obtained in were used to optimize the calculations for the case of a spill fire based on the recommended probit function Pr used to estimate the damage to people by thermal radiation. As an example of calculations, a rectilinear fragment of a pipeline on a plane, presented as a segment of a straight line, is considered. To obtain an assessment of effectiveness, 1000 sets of source data characterizing various emergency situations were randomly generated. Based on the calculations for these data sets, statistical results are presented that characterize the effectiveness of the proposed optimization method: a graph of the values of the multiplicity of the reduction in calculation time using the converted formulas; average value and standard deviation of the multiplicity of reduction of calculation time; the maximum deviation of the values calculated by the original and converted formulas.
New sorption materials based on modification of natural zeolites in metal wastewater treatment processes
Authors: Obuzdina Marina , Rush Elena
Published: December 2019

This study considers the problem of wastewater treatment from heavy metal ions and possible ways to solve it, for example, by modifications of natural zeolites from the deposits of Transbaikalia region. We offer a method of modifying the structure of natural zeolite with a sulfur-containing polymer derived from epichlorohydrin waste, the main component of the 1.2,3trichloropropane. The sulfur-containing polymer mesh is formed by the use of the dissolution of sulfur at room temperature in the system of mono-ethanolamine-hydrazine hydrate and condensation with 1.2,3-trichlorpropane. The result of applying a sulfur-containing polymer mesh lies not only in the hydrophobization of the zeolite surface, but also in the appearance of sulfur atoms in its composition, which contributes to an increase in the selectivity with respect to heavy metal ions. We demonstrate the possibility of using new sorption materials in deep wastewater treatment processes of galvanic production. As a load for the adsorbent filter, we propose to use a three-layer filtering material with a load of natural zeolite of various modifications. It has been proven that such chemical modification of zeolite allows to obtain sorbents with an increased surface area and transitional pores that have a high sorption activity in relation to heavy metal ions.
The criteria for evaluation of efficiency of heat technical installations considering general energy costs with the aim of increasing their environmental friendliness and reducing negative effect on the environment
Authors: Kulikov Alexander , Ivanova Irena , Russkova Irina , Veber Jaromír
Published: December 2019

The features of the physical meaning of the thermal coefficient useful action (CUA) ηt as a criterion for the efficiency of reversible direct circular processes are considered. In particular, we demonstrate that accounting for all energy costs when applying ηt is made by adopting a number of assumptions by default. In order to expand the possibilities for conducting thermodynamic assessments of the efficiency of various thermal power plants, a new criterion of efficiency Ku is proposed as a coefficient that takes into account in a comparable form all types of energy spent on the implementation of the cycle. In determining the criterion Ku, useful effect obtained from the implementation of a direct circular process is considered to be the specific work of the expansion of the working fluid in the cycle. Such work, in particular, can be the work of steam expansion in the turbine. The total energy cost is the sum of the specific heat supplied to the working body in a circular process and the specific mechanical work spent in the cycle on compression and pressure increase of the working body. In particular, the work is taken into account in a comparable form-taking into account the heat that was spent on its production. The analysis of the Ku criterion is carried out. As a result of the analysis we have established that at transition from the general physical model of reception of specific work of expansion in direct circular process for which Ku criterion can be applied, to the special case assuming a number of assumptions, Ku criterion can become equal to thermal coefficient useful action of a cycle. Using the Ku criterion, the efficiency of Carnot and Rankine cycles on a saturated pair is compared. The Ku score showed that the Rankine cycle was more efficient.
Environmental costs as an indicator of sustainable development
Authors: Egorova Svetlana , Bogdanovich Irina , Kistaeva Natalia , Kulachinskaya Anastasia
Published: December 2019

One of the priorities of the modern economy is the optimal use of natural resources in economic activity. This is because the organization and management of production impacts the environment, which in turn affects both the well-being of society and the indicators of economic development. Which is why methodology and practice of public non-financial reporting reflecting indicators related to the conservation and assessment of natural resources, pollution control, waste management and recycling, and creating emission standards are actively developing. Environmental costs are becoming an important tool for making informed management decisions aimed at harmonizing the economy and the environment. At present, despite a large number of methodical developments, there is no solid theoretical basis for the formation of environmental indicators that adequately characterize the interaction of the economy and the environment and economic decision-making at all levels. The article clarifies the content, classification, performance evaluation system, environmental cost assessment methods for their application in management activities for deeper analysis, modelling and predicting economic phenomena and processes within the framework of the concept of sustainable development. The authors show approaches to the valuation of anthropogenic damage to nature, determined by the disproportionateness of natural and value indicators; the lack of prices of non-market goods, great uncertainty about the true value; the duration of the effects of man-made impacts and the long-term investment in environmental protection. Modern approaches to modelling and interpretation of results are generalized, as well as the possibilities of developing new (or improving existing) models for optimizing environmental costs. The direction of analysis of environmental indicators in the existing management system has been defined, in particular, through the study of non-financial reporting, which acts as a basis for calculating resource utilization, environmental quality and sustainability.
Utilization plants in energy and water supply systems of oil and gas enterprises
Authors: Dolotovskij Igor , Dolotovskaya Nadezhda , Larin Evgeniy , Semenov Boris
Published: December 2019

Within the context of energy efficiency and environmental safety, the creation of energy and water supply systems integrated with the units for utilization of combustible waste, low-pressure gases and industrial wastewater are of high priority for oil and gas enterprises. A method for the synthesis of these rational systems and a two-dimensional model for evaluating performance indicators are proposed. We have developed alternative structures based on the block-modular principle of equipment composition formation, which allows structurally parametric integration of energy and utilization modules with technological productions; performed pre-project evaluation of the effectiveness of alternative options for the energy and water supply system with the utilization of low-pressure gases, thermal neutralization of industrial wastewater for methanol recovery plants and designed a multipurpose oil and gas condensate processing enterprise. Integration of utilization, energy and technological installations in energyand water supply systems allows reducing the consumption of heat and electric energy from external sources by 56–100%, and water consumption by 40–50%. Accordingly, the cost of wastewater reducing by an average of 76–93% for oil and gas condensate processing facilities. Almost complete utilization of low-pressure hydrocarbon gases is achieved (the volume of flared emissions is reduced by 90–98%).
The method of processing the droplet-air flow by non-equilibrium plasma
Authors: Bystrov Alexandre , Vostrov Konstantin , Frolov Vladimir , Bistrov Anatoli
Published: December 2019

The paper considers a fundamentally new installation for the processing of a droplet-air environment in a non-equilibrium plasma. Its various designs are presented. This installation is built on the basis of pulsed energy devices and is intended for water disinfection and decomposition of dissolved organic compounds, the production of nanomaterials, research in physics and chemistry, etc. We have conducted research of the performance and energy efficiency of this method of processing. It is established that in obtaining the target product, this method of processing has an advantage over the known methods: due to high performance and energy efficiency, as well as the simplicity of this processing method. In addition, the parasitic load capacity of the nanosecond generator is reduced several times, this fact increases the voltage rise rate on the cells of the plasma plasmatrons, which improves performance and energy efficiency.
Performance of a diesel engine running on mixed biofuels with the addition of gasoline
Authors: Markov Vladimir , Kamaltdinov Vyacheslav , Bykovskaya Larisa , Sa Bowen
Published: December 2019

The significance of the paper is confirmed by the need to replace petroleum motor fuels with fuels produced from alternative energy sources. Biofuels derived from various vegetable resources are considered as promising alternative fuels for diesel engines. These fuels offer significant advantages with respect to the renewability of their raw materials and good emission performances when burned in ICEs. The main problem of using vegetable oils as biofuels for diesel engines is their high viscosity. This problem can be resolved by using mixed biofuels with the addition of gasoline. The analysis of physico-chemical properties of petroleum diesel fuel (DF) and mixed biofuels containing petroleum DF, rapeseed oil (RO) and AI-80 automotive gasoline was conducted. Experimental studies of the D-245.12S diesel fuelled with these mixed fuels were carried out. The mixed fuels were prepared from 80% DF + 20% RO, from 75% DF + 20% RO + 5% AI-80, and from 70% DF + 20% RO + 10% AI-80. It was shown that the addition of gasoline to mixed biofuels could improve two main toxicity indicators of exhaust gases exhaust gases smoke and emissions of nitrogen oxides. The best emission performance was achieved for the mixture of 70% DF, 20% RO and 10% AI-80. When the diesel engine was switched from the mixture of 80% DF and 20% RO to the mixture of 70% DF, 20% RO and 10% AI-80, the exhaust gases smoke at maximum torque mode decreased from 17.5 to 14.5% on the Hartridge scale, i.e. by 17.1%. The specific emissions of nitrogen oxides decreased from 6.559 to 6.154 g/(kW·h), i.e. by 6.2%.
Adhesive strength in a high voltage mica insulation system
Authors: Shikova Tatiana
Published: December 2019

The problem of maintaining a monolithic high-voltage mica insulation made by the Resin Rich technology for windings of electrical machines and conductors is considered. The violation of solidity like delaminations and peeling off from conductor can happen both during the process of manufacturing and during exploitation of constructions. The possibility of breaking the solidity is directly related to the magnitude of adhesion strength. Design and manufacturing technology of samples in laboratory and industrial conditions to determine the adhesion strength were developed. Adhesive strength is determined by the method of shear and tensile test method between insulation layers and in system of metal- mica insulation.The created method for the manufacture of samples made it possible to test samples with various designs of adhesive contact, materials of adhesive contact and technological parameters of the pressing process. The adhesion strength depends on the parameters of the thermal pressing process and the degree of curing of the binder in the initial resin rich tape. Adhesive contact of mica insulation to metal through fiberglass is more durable than through film
Berufspolitik
Authors: Reichardt Michael , Eikelmann Matthias , Wiegard-Szramek Ina
Published: December 2019

Auf Einladung der Deutschen Gesellschaft für Nephrologie (DGfN) hat sich eine Arbeitsgruppe zur Qualifizierung und Quantifizierung von Personal in der Dialyseversorgung gebildet. Vertreter der DGfN, des KfH Kuratoriums für Dialyse und Nierentransplantation e. V., des Verbands Deutsche Nierenzentren (DN) e. V., der PHV – Der Dialysepartner, Patienten-Heimversorgung Gemeinnützige Stiftung und für die Pflege Vertreter des Fachverbandes nephrologischer Berufsgruppen (fnb) e. V. nehmen an dieser Initiative teil. Ziel ist eine Veröffentlichung von Anhaltszahlen im Dialysestandard. In diesem Artikel führt der fnb als Vertreter der nephrologischen Pflege seinen Anteil an dieser wichtigen Arbeit aus.
Dialyse beim akuten Nierenversagen
Authors: Feldkamp Thorsten
Published: December 2019

Der beste Zeitpunkt des Dialysebeginns beim akuten Nierenversagen (ANV) wird immer noch kontrovers diskutiert, was im intensivmedizinischen Bereich häufig zur Unsicherheit beim Management von Patienten mit einem schweren ANV führt. So erlaubt die Dialyse zwar eine bessere Steuerung des Volumen- und Elektrolythaushalts, kann aber u. a. katheterassoziierte Infektionen oder Blutdruckabfälle auslösen. Deswegen muss der Einsatz der Dialysebehandlung kritisch abgewogen werden. Aus diesem Grunde wurde nun in einer randomisierten und prospektiven Studie an kritisch kranken Patienten mit ANV untersucht, ob der frühe Zeitpunkt des Dialysebeginns die Prognose des Patienten beeinflusst.
Peritonealdialyse beim akuten Nierenversagen und in der Intensivmedizin
Authors: Koch Michael , Kohnle Matthias , Aker Sendogan
Published: December 2019

Das akute Nierenversagen (ANV) mit Nierenersatztherapie-Pflichtigkeit ist ein häufiges Krankheitsbild auf den Intensivstationen, verbunden mit hoher Mortalität. Als Nierenersatztherapie-Verfahren werden v. a. extrakorporale Methoden eingesetzt. Untersuchungen in den letzten Jahren zeigen, dass die Peritonealdialysetherapie eine effektive, sichere und durchführbare komplementäre Alternative zu den extrakorporalen Verfahren nicht nur bei Patienten mit chronischem, sondern auch bei (intensivpflichtigen) Patienten mit ANV darstellt. Die Peritonealdialyse (PD) bietet methodische Vorteile wie die Vermeidung eines Kathetergefäßzuganges mit entsprechendem Bakteriämie- und Sepsisrisiko, einen gleichmäßigen Flüssigkeitsentzug mit geringerer hämodynamischer Instabilität, einem fehlenden Antikoagulationsbedarf und einer Fortführbarkeit der Nierenersatztherapie bei fortbestehender Dialysepflichtigkeit. Insbesondere wäre die PD zu erwägen bei Erkrankungen wie fortgeschrittener chronischer Herzinsuffizienz mit kardiorenalem Syndrom, Leberzirrhose mit refraktärem Aszites, akut auf chronischem Nierenversagen mit anzunehmender chronischer Nierenersatztherapiepflichtigkeit, bei schlechten Gefäßzugangsmöglichkeiten und bei erhöhtem Blutungsrisiko. Bei bestimmten klinischen Situationen wie Septikämien mit Katecholamin-Pflichtigkeit und möglichem peritonealem Ultrafiltrationsverlust sowie aktiven chronisch-entzündlichen Darmerkrankungen sollte jedoch den extrakorporalen Verfahren der Vorzug gegeben werden. Ein limitierender Faktor für den Einsatz der PD kann insbesondere die akute und zeitige Anlage des PD-Katheters beim kritisch kranken Patienten darstellen. Jedoch erscheint dies durch die Etablierung einer entsprechenden Vorgehensweise und Methode mit Kooperation der beteiligten Disziplinen vor Ort auch in der Akutsituation möglich.
Lösungsmöglichkeiten bei fehlgeschlagenen Osteosynthesen in der Mund-, Kiefer- und Gesichtschirurgie
Authors: Koerdt Steffen , Sabatakakis Antonis , Heiland Max , Kreutzer Kilian
Published: December 2019

Die osteosynthetische Versorgung mit Miniplatten oder Rekonstruktionsplatten stellt in der Mund-, Kiefer- und Gesichtschirurgie den operativen Standard in Versorgung von Gesichtsschädelfrakturen und bei der Fixation autologen Knochentransplantate dar. Intra- und extraorale Zugangswege zum knöchernen Gesichtsschädel sowie die Belastung durch Kaukräfte, Lagebeziehung zur Mundhöhle und Nasennebenhöhlensystem sowie die Okklusion können zu einem Misserfolg der Osteosynthese beitragen. Zu den häufigsten Komplikationen gehören Materiallockerung, Materialbruch, sekundäre Fragmentdislokation und Infektion.
Metabolic Profiling and Untargeted 1H-NMR-Based Metabolomics Study of Different Iranian Pomegranate (Punica granatum) Ecotypes
Authors: Hasanpour Maede , Saberi Satar , Iranshahi Mehrdad
Published: December 2019

Pomegranate (Punica granatum) is an ancient fruit that is widely consumed as fresh fruit and juice. The aim of the present study was to compare the metabolic profile of pomegranate ecotypes from different geographical origins of Iran, the largest producer of pomegranates in the world. 1H-NMR and 2D NMR spectroscopy were applied to investigate the ecotypic variation. Multivariate data analyses were used to identify overall metabolic differences. Mazandaran pomegranate samples were found to be different from the other ecotypes, having a high content of citric and succinic acids. Bajestan, Ferdows, and Yazd pomegranates contained comparatively higher amounts of anthocyanins and ellagic acid derivatives than other pomegranate ecotypes. The distribution of metabolites among different ecotypes of pomegranate is discussed on the basis of these findings.
1500 Euro Preisgeld
Authors: Schäfer Christian
Published: December 2019

Die Thieme Gruppe schreibt im Jahr 2020 wieder den Förderpreis Nephrologische Pflege aus und stiftet das Preisgeld von 1500 Euro.
A Reduction-Sensitive Fluorous Fluorogenic Coumarin
Authors: Miller Margeaux A. , Day Rachael A. , Estabrook Daniel A. , Sletten Ellen M.
Published: December 2019

Fluorophores that are sensitive to their environment are useful tools for sensing chemical changes and probing biological systems. Here, we extend responsive fluorophores to the fluorous phase with the synthesis of a reduction-sensitive fluorous-soluble fluorogenic coumarin. We demonstrate that this fluorophore responds to various reducing agents, most notably glutathione, a key biological reductant. The fluorous solubility of this probe allows for its encapsulation into two different fluorous nanomaterials: perfluorocarbon nanoemulsions and fluorous core-shell micelles. The fluorogenic coumarin allows us to study how efficiently these vehicles protect the contents of their interior from the external environment. In the presence of glutathione, we observe different degrees of release for micelles and emulsions. This understanding will help guide future applications of fluorous nanomaterials as drug delivery vehicles.
An Evaluation of System End-User Support during Implementation of an Electronic Health Record Using the Model for Improvement Framework
Authors: Kiepek Wendy , Sengstack Patricia P.
Published: December 2019

Background Electronic health record (EHR) system implementation is complex. Strong support for clinicians and other end-users during the initial phase of implementation requires dedicated resources and commitment to ensure a smooth transition, reduce frustration, and assist in adoption.

Objectives Evaluate end-user support processes and personnel employed during the initial phase of EHR implementation at an academic medical center and identify facilitators of success, challenges, and lessons learned.

Methods Using the model for improvement framework, this case report describes the activities that follow the concepts of planning, doing, studying, and acting (PDSA) when providing on-site support to system end users during an EHR implementation in a complex health care system.

Results Strengths included engaged and supportive leadership, use of internal support personnel, use of zone leaders, daily huddles for effective dissemination of information, and an evaluation survey tool to provide data supporting rapid changes in support personnel allocation. Challenges primarily surrounded the management of over 1,000 external support personnel which included limited EHR system knowledge, scheduling, and transportation logistics.

Conclusion Implementation of EHR systems continues. Supporting end users is one aspect of these complex projects that require dedicated resources to manage effectively. Organizations taking a more proactive approach, based on learning from experiences, as well as from other health care organizations, can improve their ability to take on this challenge armed with best practices and lessons learned.
Algebraic backgrounds for noncommutative Kaluza-Klein theory. I. Motivations and general framework
Authors: Besnard Fabien
Published: December 2019

We investigate the representation of diffeomorphisms in Connes’ spectral triple formalism. By encoding the metric and spin structure in a moving frame, it is shown on the paradigmatic example of spin semi-Riemannian manifolds that the bimodule of noncommutative 1-forms Ω1 is an invariant structure in addition to the chirality, real structure, and Krein product. Adding Ω1 and removing the Dirac operator from an indefinite spectral triple, we obtain a structure which we call an algebraic background. All the Dirac operators compatible with this structure then form the configuration space of a noncommutative Kaluza-Klein theory. We explore the algebraic background canonically attached to a spin manifold, showing that its automorphism group is generated by diffeomorphisms and spin structure equivalences, and that its configuration space contains the Dirac operators associated with metrics and compatible spin structures, as well as additional centralizing fields. We explain how the latter can be removed without breaking the symmetries.
Angular displacement modeling and excitation signal optimization for a stepping giant magnetostrictive rotary actuator
Authors: Zhou Jingtao , He Zhongbo , Bai Guo , Liu Guoping
Published: December 2019

Giant magnetostrictive rotary actuators (GMRAs) can realize rotary motion in large scale and with high precision. A series of rectangular voltage signals organized in strict order exerted on GMRA helps its clamping mechanism and driving mechanism complete specific actions such as clamping, loosening, and actuating, thus leading to the stepping output of the rotor. In order to describe the overall performance of GMRA, an angular displacement model is established, which can be divided into four parts, namely, the current model, magnetic field model, output force model, and vibration model. The experimental results indicate that the established model agrees well with the actual performance of GMRA in operating conditions. After that, utilizing the established model, simulations are conducted to analyze the angular response of GMRA. According to the simulation results, the order of driving signals is optimized, making the maximum driving frequency rise from 160 Hz to 210 Hz, while the peak angular speed of GMRA reaches 70.77 mrad/s. The modeling and optimization methods proposed in this paper can be helpful for the structural optimization and controller design of GMRA as well.
Observability of laminar bidimensional fluid flows seen as autonomous chaotic systems
Authors: Charó Gisela D. , Sciamarella Denisse , Mangiarotti Sylvain , Artana Guillermo , Letellier Christophe
Published: December 2019

Lagrangian transport in the dynamical systems approach has so far been investigated disregarding the connection between the whole state space and the concept of observability. Key issues such as the definitions of Lagrangian and chaotic mixing are revisited under this light, establishing the importance of rewriting nonautonomous flow systems derived from a stream function in autonomous form, and of not restricting the characterization of their dynamics in subspaces. The observability of Lagrangian chaos from a reduced set of measurements is illustrated with two canonical examples: the Lorenz system derived as a low-dimensional truncation of the Rayleigh-Bénard convection equations and the driven double-gyre system introduced as a kinematic model of configurations observed in the ocean. A symmetrized version of the driven double-gyre model is proposed.
Development of gamma ray spectrometer with high energy and time resolutions on EAST tokamak
Authors: Zhou R. J. , Zhong G. Q. , Hu L. Q. , Tardocchi M. , Rigamonti D. , Giacomelli L. , Nocente M. , Gorini G. , Fan T. S. , Zhang Y. M. , Hu Z. M. , Xiao M. , Li K. , Zhang Y. K. , Hong B. , Zhang Y. , Lin S. Y. , Zhang J. Z.
Published: December 2019

A new gamma ray spectrometer with high energy and time resolutions has been developed and installed on the EAST tokamak to study fast ion and runaway electron behaviors. The spectrometer is based on a LaBr3(Ce) scintillator detector and a fully digital data acquisition system that is based on a digitizer with digital pulse processing algorithms. The energy resolution of the spectrometer is about 3.9% at 662 keV, and the spectrometer can operate stably at a counting rate as high as 1 MHz, monitored by using a light emitting diode monitoring system. The measured gamma ray spectrum is simulated based on Geant4 and unfolded with the high-resolution boosted Gold deconvolution algorithm, aiming at reconstructing the energy distribution functions of fast ions and runaway electrons.
Strain engineering on the metal-insulator transition of VO2/TiO2 epitaxial films dependent on the strain state of vanadium dimers
Authors: Hong Bin , Yang Yuanjun , Hu Kai , Dong Yongqi , Zhou Jingtian , Zhang Yue , Zhao Weisheng , Luo Zhenlin , Gao Chen
Published: December 2019

In this letter, a series of vanadium dioxide (VO2) epitaxial films were deliberately deposited on TiO2 substrates with different orientations [(001), (110), and (101)], in an attempt to gain insights into the strained VO2 epitaxial film. We found in-plane [100] and [1-10] directions, obviously anisotropic metal-insulator transition (MIT) in (110)-oriented VO2 films. In combination with synchrotron radiation high-resolution x-ray diffraction characterizations, electronic transport data reveal that the critical temperature of MIT depends on the strain state of the dimeric vanadium atomic chain along the c axis of the rutile phase. The anisotropy of MIT is closely related to the orientation of the VO2 films, which is caused by the varied orientation configuration of V-V atomic chain dimerization in the films. Soft x-ray absorption spectroscopy results further indicate that this anisotropy may be driven by the directional hybridization of O 2p and V 3d orbitals with respect to the orientation of VO2 thin films. The polarization-dependent V L-edge and O K-edge XAS data suggest that the elongation of the apical V-O bond length increases the p-d orbital overlap; thus, the energy level of the d// orbital is raised relative to that of the π* orbital. These anisotropic MIT behaviors will help us to understand how the strain engineering depends on the strain state of vanadium dimers in VO2 films.
Short-time dynamics and decay mechanism of E,E-2,4-hexadienal in the first light-absorbing S2(ππ*) state
Authors: Liu Jiafeng , Xue Jiadan , Zhao Yanying , Zheng Xuming
Published: December 2019

The initial nonadiabatic decay dynamics of E,E-2,4-hexadienal (HAL) in the light absorbing S2(ππ*) state were studied using resonance Raman spectroscopy and complete-active space self-consistent field (CASSCF) calculations. The UV and vibrational spectra were assigned on the basis of the UV absorption, Fourier transform (FT)-Raman and FT-infrared measurements, the density-functional theory computations, and the normal mode analysis. The A-band resonance Raman spectra in cyclohexane and acetonitrile were obtained at 282.4, 273.9, 266.0, 252.7, and 245.9 nm excitation wavelengths, respectively, to probe the corresponding structural dynamics of HAL. The A-band absorption cross section and the corresponding absolute resonance Raman cross sections were simulated using a simple model based on the time-dependent wave-packet theory in a Brownian oscillator model. The geometric structures of the singlet electronic excited states and their curve-crossing points were optimized at the CASSCF level of theory. The obtained short-time structural dynamics in easy-to-visualize internal coordinates were then compared with the CASSCF-predicted structural-parameter changes of S2(ππ*)S1(nπ*)-n (n = 1–4). Our results indicate that the initial population of HAL in the S2 state ramifies in or nearby the Franck–Condon (FC) region, leading to five S2(ππ*) → S1(nπ*) internal conversion pathways due to the flexibility of the molecular chain and the different electronic resonant structures formed nearby FC of the S2 state. Then, the formed S1 transient species, which have different geometric structures and different energy partitions, undergo different photophysical processes, such as S1 → S0 internal conversion, S1 → T1 intersystem crossing, and the S1 → S′1 photoisomerization reaction. The substitution effect on the S2(ππ*) → S1(nπ*) internal conversion dynamics and the trans–cis photoisomerization reaction is proposed in terms of the p-π conjugation interaction or the p-σ superconjugation interaction.
Detection of the thermoacoustic combustion instabilities of a slot burner based on a diagonal-wise recurrence quantification
Authors: Hernandez-Rivera R. , Troiani G. , Pagliaroli T. , Hernandez-Guerrero A.
Published: December 2019

This paper presents a nonlinear time-series analysis of the thermoacoustic instabilities of an experimental slot burner. The main objective was the calculation of indexes capable of detecting in advance the combustion instabilities by gradually increasing the flow Reynolds number of the pilot burner. A chaotic analysis based on diagonalwise measurements of the recurrence plots was performed on the basis of which the following indexes were calculated: the τ-recurrence rate index RRτ, the τ-determinism index DETτ, the τ-average diagonal line length index Lτ, and the τ-entropy index sτ. A quantification carried out by means of the standard deviation σ and mean values μ of the diagonalwise measurements showed that the aforementioned indexes were successfully able to sort all cases under analysis mainly into two groups: the first three cases that correspond to the stable regime named “Combustion Noise” and the remaining cases that were associated with the unstable regime called “Combustion Instability.” Additionally, the particle image velocimetry optical method was applied in order to compute a new index based on the velocity fields. The results showed that the index Vh, based on the local heights of the velocity profiles of the central flame, was also capable of detecting the same two groups previously identified by the nonlinear analysis. Nevertheless, the most sensitive indexes were the indexes RRτμ, DETτσ, and sτσ since these indexes were able to detect the transition between the combustion noise and combustion instability regimes. Therefore, the present results proved that the proposed five indexes were effective precursors in order to detect in advance the combustion instabilities.
Gigahertz-repetition-rate, narrowband-deep-ultraviolet light source for minimization of acquisition time in high-resolution angle-resolved photoemission spectroscopy
Authors: Yoshioka K. , Omachi J. , Sakano M. , Shimojima T. , Ishizaka K. , Kuwata-Gonokami M.
Published: December 2019

Ultrahigh-repetition-rate (1.1 GHz), deep-ultraviolet coherent light at 208.8 nm is generated by applying an external Fabry–Pérot cavity for repetition-rate multiplication to the fourth harmonics of a 10-ps, mode-locked Ti:sapphire laser. Its small pulse energy minimizes the unwanted space charge effect, while its high repetition rate drastically reduces the acquisition time in high-energy resolution angle-resolved photoemission spectroscopy using hemispherical electron analyzers. The absence of the space charge effect in the photoemission spectrum near the Fermi edge of polycrystalline Au at 8 K demonstrates this idea.
Loss of coherence among coupled oscillators: From defect states to phase turbulence
Authors: Duguet Yohann , Maistrenko Yuri L.
Published: December 2019

Synchronization of a large ensemble of identical phase oscillators with a nonlocal kernel and a phase lag parameter α is investigated for the classical Kuramoto-Sakaguchi model on a ring. We demonstrate, for low enough coupling radius r and α below π/2, a phase transition between coherence and phase turbulence via so-called defect states, which arise at the early stage of the transition. The defect states are a novel object resulting from the concatenation of two or more uniformly twisted waves with different wavenumbers. Upon further increase of α, defects lose their stability and give rise to spatiotemporal intermittency, resulting eventually in developed phase turbulence. Simulations close to the thermodynamic limit indicate that this phase transition is characterized by nonuniversal critical exponents.
Development of 1.2-GHz ECR ion source and Wien filter for inexpensive ion beam processing system
Authors: Asaji Toyohisa , Uyama Hiroya , Umetsugu Takuro , Nakamura Tsubasa , Hitobo Takeshi , Kato Yushi
Published: December 2019

A desktop-sized ion beam processing system with an inexpensive electron cyclotron resonance (ECR) ion source has been developed for industrial applications at the National Institute of Technology, Toyama College. A commercially available 1.2- to 1.3-GHz transceiver is adopted as a microwave source to generate the ECR plasma. The minimum-B magnetic field is formed by arranging small rectangular permanent magnets. A Wien filter with orthogonal electric and magnetic fields is employed as a beam separator. At the end of the beam line, a processing chamber with a substrate stage for ion beam applications, such as ion implantation and microfabrication, is installed. Here, we report the results of the first experiment. Ar ion beams with a current of approximately 62 µA were obtained at an extraction voltage of 4 kV. In addition, we demonstrate that Ar and Xe ions can be separated by the Wien filter.
Optical spectroscopy as a diagnostic tool for metal ion beam production with an ECRIS
Authors: Maimone F. , Mäder J. , Lang R. , Patchakui P. T. , Tinschert K. , Hollinger R.
Published: December 2019

At GSI, the CAPRICE ECRIS is used to provide heavy ion beams to the UNILAC (Universal Linear Accelerator) accelerator. In order to satisfy the demand of metal ion beams, a resistively heated oven is routinely used. This evaporation technique allows the ion beam production from natural and enriched solid elements or compounds with high efficiency and low material consumption. Often it is required to provide high charge state ion beams from rare or extremely rare isotopes as 48Ca, e.g., for the investigation of super heavy elements. In order to maintain the ion beam stable for the entire scheduled beam time, the plasma inside the ion source must remain as stable as possible. The tuning of ion source parameters and oven power affecting the oven temperature and, in turn, the evaporation rate is necessary. A strong relationship between the microwave power and the oven heating was observed, thus affecting the power control, the plasma stability, and the material consumption. Hence, it was investigated how an optical spectrometer can be used as a predictive diagnostic tool to detect ion source instabilities. Furthermore, the effect of parasitic oven heating by coupling of microwaves was investigated. Optical emission spectroscopy was performed by analyzing the light from the plasma and from the oven through the extraction aperture. The measurements enabled us to distinguish between resistive heating and microwave heating. The results of this investigation are presented.
Semiballistic thermal conduction in polycrystalline SiGe nanowires
Authors: Okamoto Noboru , Yanagisawa Ryoto , Anufriev Roman , Mahfuz Alam Md. , Sawano Kentarou , Kurosawa Masashi , Nomura Masahiro
Published: December 2019

Ballistic heat conduction remains a controversial nanoscale phenomenon because of its occurrence and strength depending on the material, alloy composition, and temperature. Here, we discuss the impact of ballistic thermal conduction and compare the results with theoretical predictions. We experimentally investigate ballistic thermal transport in SiGe polycrystalline nanowires by measuring the length dependence of thermal conductivity for different alloy compositions and temperatures. At room temperature, our experiments show that ballistic effects are negligible in nanowires made of pure polycrystalline Si but become stronger as the Ge composition increases. As we decreased the temperature, we observed that ballistic contribution becomes even stronger.
The influence of edge structure on the optoelectronic properties of Si2BN quantum dot
Authors: Mahida H. R. , Singh Deobrat , Sonvane Yogesh , Thakor P. B. , Ahuja Rajeev , Gupta Sanjeev K.
Published: December 2019

In recent work, we have investigated the electronic and optical properties of pristine and functionalized Si2BN quantum dots (QDs) using first-principles calculations. Due to the edge functionalization, Si2BN QDs have binding energies of −0.96 eV and −2.08 eV per hydrogen atom for the adsorption of single and double hydrogen atoms, respectively. These results reveal the stability and the bonding nature of hydrogen at the edges of Si2BN QD. In particular, the charge transfer between hydrogen and other atoms is explicitly increased. The electronic band structure of pristine Si2BN QD shows a metallic behavior with a finite number of electronic states in the density of states at the Fermi level. The frequency-dependent optical properties, such as refractive index, extinction coefficient, absorption coefficient, electron energy loss spectra, and reflectivity, are computed for both the parallel and perpendicular components of electric field polarization. The higher absorption was found in the infrared regime. The present study shows that the functionalization of Si2BN QD by two hydrogen atoms is energetically stable. It offers a promising application of Si2BN QD, which can be used in optical nanodevices such as photodetectors and biomedical imagination.
First-principles prediction of multiple stationary states in glass-forming liquids
Authors: Lira-Escobedo J. , Varela-Varela D. , Mendoza-Méndez P. , Ramírez-González P. E.
Published: December 2019

In the present work, the Non-Equilibrium Self-Consistent Generalized Langevin Equation (NESCGLE) theory is used to predict the final state of glass-forming liquids subjected to different cooling processes. We show that the NESCGLE theory correctly describes two essential features of the glass transition. Such features are the structural recovery and the dependence of the final state with the cooling rate. We demonstrate that below a particular temperature Tc, the system is unable to equilibrate, independently of the cooling rate. We show that the equilibrium state is only reached for the quasistatic process. Additionally, we show how, from the NESCGLE theory, it is possible to deduce a relaxation model of structural recovery, for which we obtain molecular expressions of the parameters.
Anodic decomposition of surface films on high voltage spinel surfaces—Density function theory and experimental study
Authors: Leung Kevin , Rosy  , Noked Malachi
Published: December 2019

Oxidative decomposition of organic-solvent-based liquid electrolytes at cathode material interfaces has been identified as the main reason for rapid capacity fade in high-voltage lithium ion batteries. The evolution of “cathode electrolyte interphase” (CEI) films, partly or completely consisting of electrolyte decomposition products, has also recently been demonstrated to correlate with battery cycling behavior at high potentials. Using density functional theory calculations, the hybrid PBE0 functional, and the (001) surfaces of spinel oxides as models, we examine these two interrelated processes. Consistent with previous calculations, ethylene carbonate (EC) solvent molecules are predicted to be readily oxidized on the LixMn2O4 (001) surface at modest operational voltages, forming adsorbed organic fragments. Further oxidative decomposition of such CEI fragments to release CO2 gas is however predicted to require higher voltages consistent with LixNi0.5Mn1.5O4 (LNMO) at smaller x values. We argue that multistep reactions, involving first formation of CEI films and then further oxidization of CEI at higher potentials, are most relevant to capacity fade. Mechanisms associated with dissolution or oxidation of native Li2CO3 films, which are removed before the electrolyte is in contact with oxide surfaces, are also explored.