bluuebunny/crossref_metadata_2025 huggingface dataset:
Li-ion intercalation enhanced ferromagnetism in van der Waals Fe3GeTe2 bilayer
Authors: Huang Xiaokun , Xu Jinlin , Zeng Renfen , Jiang Qinglang , Nie Xin , Chen Chao , Jiang Xiangping , Liu Jun-Ming
Published: July 2021

Recently, the issue of ferromagnetism enhancement in two-dimensional (2D) van der Waals (vdW) layered magnetic systems has been highly concerned. It is believed that ion intercalation in vdW layered ferromagnets, targeting either enhanced interlayer spin exchanges or intralayer ones, can be an efficient scheme. In this work, by means of the first-principles calculations, we investigate the Li-ion intercalation between the two monolayers of the ferromagnetic (FM) vdW Fe3GeTe2 (FGT) bilayer and its impact on the ferromagnetism. It is revealed that the Li-ion intercalation provides hopping carriers between the two interfacial Te sublayers, beneficial for the enhancement of the interlayer FM coupling at a relatively low intercalation level. On the other hand, the Li-ion intercalation lifted Fermi level promotes the electron transfer from the minority spin channel to the majority one for the Fe-3d bands, favoring the stronger intralayer FM coupling. However, the over-intercalation generated carriers may fill up the majority spin channel, reversely leading to the reduced interlayer FM coupling. Consequently, an optimized intercalation level is expected in terms of ferromagnetism enhancement. This work not only helps to explain the recent experimental finding on the gate-controlled Li-ion intercalation in vdW FGT few-layers but also suggests a general scheme for ferromagnetism enhancement in 2D vdW layered ferromagnets using the ion intercalation approach.
Ultrafast non-thermal and thermal switching in charge configuration memory devices based on 1T-TaS2
Authors: Mihailovic D. , Svetin D. , Vaskivskyi I. , Venturini R. , Lipovšek B. , Mraz A.
Published: July 2021

Charge configuration memory (CCM) device operation is based on the controllable reconfiguration of electronic domains in a charge-density-wave material. Since the dominant effect involves the manipulation of electrons rather than atoms, the devices can display sub-picosecond switching speed and ultralow, few femtojoule switching energy. The mechanisms involved in switching between domain states of different electrical resistances are highly non-trivial and involve trapping non-equilibrium charges within topologically protected domain states. Here, we discuss the underlying physics that are deemed essential for the operation of CCM devices, focusing on the unusual asymmetry between non-thermal “write” processes and thermal “erase” processes from the point of view of the mechanism in relation to the thermal dynamics.
Two-dimensional electronic–vibrational spectroscopy: Exploring the interplay of electrons and nuclei in excited state molecular dynamics
Authors: Arsenault Eric A. , Bhattacharyya Pallavi , Yoneda Yusuke , Fleming Graham R.
Published: July 2021

Two-dimensional electronic–vibrational spectroscopy (2DEVS) is an emerging spectroscopic technique which exploits two different frequency ranges for the excitation (visible) and detection (infrared) axes of a 2D spectrum. In contrast to degenerate 2D techniques, such as 2D electronic or 2D infrared spectroscopy, the spectral features of a 2DEV spectrum report cross correlations between fluctuating electronic and vibrational energy gaps rather than autocorrelations as in the degenerate spectroscopies. The center line slope of the spectral features reports on this cross correlation function directly and can reveal specific electronic–vibrational couplings and rapid changes in the electronic structure, for example. The involvement of the two types of transition moments, visible and infrared, makes 2DEVS very sensitive to electronic and vibronic mixing. 2DEV spectra also feature improved spectral resolution, making the method valuable for unraveling the highly congested spectra of molecular complexes. The unique features of 2DEVS are illustrated in this paper with specific examples and their origin described at an intuitive level with references to formal derivations provided. Although early in its development and far from fully explored, 2DEVS has already proven to be a valuable addition to the tool box of ultrafast nonlinear optical spectroscopy and is of promising potential in future efforts to explore the intricate connection between electronic and vibrational nuclear degrees of freedom in energy and charge transport applications.
Space charge in a vacuum diode: From macroscopic to microscopic gaps
Authors: Hassan Mohab O. , Takahata Kenichi , Nojeh Alireza
Published: July 2021

The space charge effect is important in free-electron devices and sometimes plays a key role. A vacuum-compatible micromanipulation platform was devised to study this effect in a diode structure while changing the width of the gap between the emitter and the collector in situ in the range of hundreds of micrometers to tens of micrometers. The current–voltage characteristics were found to upshift with a decrease in the interelectrode distance; the space charge-limited current increased by approximately two orders of magnitude when the interelectrode distance decreased from 550 to 50 μm. The simplicity of the parallel-plate structure enabled analysis based on one-dimensional emission and transport with the measurement results showing a good fit to the model by Longo combined with the Child–Langmuir theory.
Seeding the explosion of a high-current-density conductor in a controlled manner through the addition of micron-scale surface defects
Authors: Awe T. J. , Yu E. P. , Hatch M. W. , Hutchinson T. M. , Tomlinson K. , Tatum W. D. , Yates K. C. , Hutsel B. T. , Bauer B. S.
Published: July 2021

Inhomogeneities in a current-carrying conductor promote non-uniform heating and expansion through the complex feedback between current density, electrical resistivity, Ohmic heating, temperature, and hydrodynamics. Three-dimensional-magnetohydrodynamic (3D-MHD) simulations suggest that μm-scale resistive inclusions or voids seed local overheating and through hydrodynamic explosion generate continuously growing craters which become several times larger than the initial perturbation. The ejected mass is the genesis of an electrothermally driven plasma filament which develops at lower current than plasmas on uniform surfaces adjacent to the defect. This result suggests that 1D or even 2D treatments are largely inadequate for detailed prediction of plasma formation. To test computational predictions, z-pinch experiments driven to 1 MA studied ultra-high-purity aluminum rods which were then machined to include pairs of quasi-hemispherical voids or “engineered defects (ED)” on the current-carrying surface. ED are the dominant current-density perturbation and reproducibly drive local overheating which can be compared with 3D-MHD simulation. Data from high-resolution-gated imagers of visible surface emissions confirm many simulation predictions, including the surface topography of local overheating, and the propensity for neighboring ED to prematurely source plasmas which then connect to form a plasma filament. Results also provide conditional support of theory which suggests heating similarity; that is, heating is independent of ED size for geometrically scaled ED.
Shock to detonation transition of pentaerythritol tetranitrate (PETN) initially pressed to 1.65 g/cm3
Authors: Aslam Tariq D. , Bolme Cynthia A. , Ramos Kyle J. , Cawkwell Marc J. , Ticknor Christopher , Price Matthew A. , Leiding Jeffery A. , Sanchez Nathaniel J. , Andrews Stephen A.
Published: July 2021

A novel set of experiments and reactive flow modeling of pentaerythritol tetranitrate (PETN) is presented. Here, the specific phenomenon of shock to detonation transition is examined, where an initial, relatively weak shock is propagated into pressed PETN powder at 1.65 g/cm3 and the subsequent buildup to detonation is observed experimentally. These experiments, in conjunction with reactant and products’ equations of state, are utilized for building reactive flow models.
Interpretation of multiple solutions in fully iterative GF2 and GW schemes using local analysis of two-particle density matrices
Authors: Pokhilko Pavel , Zgid Dominika
Published: July 2021

Due to the presence of non-linear equations, iterative Green’s function methods can result in multiple different solutions even for simple molecular systems. In contrast to the wave-function methods, a detailed and careful analysis of such molecular solutions was not performed before. In this work, we use two-particle density matrices to investigate local spin and charge correlators that quantify the charge resonance and covalent characters of these solutions. When applied within the unrestricted orbital set, spin correlators elucidate the broken symmetry of the solutions, containing necessary information for building effective magnetic Hamiltonians. Based on GW and GF2 calculations of simple molecules and transition metal complexes, we construct Heisenberg Hamiltonians, four-spin-four-center corrections, and biquadratic spin–spin interactions. These Hamiltonian parameterizations are compared to previous wave-function calculations.
Ab initio molecular dynamics with screened Lorentz forces. I. Calculation and atomic charge interpretation of Berry curvature
Authors: Culpitt Tanner , Peters Laurens D. M. , Tellgren Erik I. , Helgaker Trygve
Published: July 2021

The dynamics of a molecule in a magnetic field is significantly different from its zero-field counterpart. One important difference in the presence of a field is the Lorentz force acting on the nuclei, which can be decomposed as the sum of the bare nuclear Lorentz force and a screening force due to the electrons. This screening force is calculated from the Berry curvature and can change the dynamics qualitatively. It is therefore important to include the contributions from the Berry curvature in molecular dynamics simulations in a magnetic field. In this work, we present a scheme for calculating the Berry curvature numerically using a finite-difference technique, addressing challenges related to the arbitrary global phase of the wave function. The Berry curvature is calculated as a function of bond distance for H2 at the restricted and unrestricted Hartree–Fock levels of theory and for CH+ as a function of the magnetic field strength at the restricted Hartree–Fock level of theory. The calculations are carried out using basis sets of contracted Gaussian functions equipped with London phase factors (London orbitals) to ensure gauge-origin invariance. In this paper, we also interpret the Berry curvature in terms of atomic charges and discuss its convergence in basis sets with and without London phase factors. The calculation of the Berry curvature allows for its inclusion in ab initio molecular dynamics simulations in a magnetic field.
Spin-lattice dynamics of surface vs core magnetization in Fe nanoparticles
Authors: dos Santos Gonzalo , Meyer Robert , Aparicio Romina , Tranchida Julien , Bringa Eduardo M. , Urbassek Herbert M.
Published: July 2021

Magnetization of clusters is often simulated using atomistic spin dynamics for a fixed lattice. Coupled spin-lattice dynamics simulations of the magnetization of nanoparticles have, to date, neglected the change in the size of the atomic magnetic moments near surfaces. We show that the introduction of variable magnetic moments leads to a better description of experimental data for the magnetization of small Fe nanoparticles. To this end, we divide atoms into a surface-near shell and a core with bulk properties. It is demonstrated that both the magnitude of the shell magnetic moment and the exchange interactions need to be modified to obtain a fair representation of the experimental data. This allows for a reasonable description of the average magnetic moment vs cluster size, and also the cluster magnetization vs temperature.
Performance comparison among the variants of curved serpentine coil
Authors: Awasthi Kuldeep , Reddy Desireddy Shashidhar , Khan Mohd. Kaleem
Published: July 2021

In the present work, two variants of the novel curved serpentine coil formed by relaxing the switching angle at the junctions are explored and compared with the original design for the same mean radius Rm of concentric tubes. With α as the semi-cone angle and θ as the subtended angle of concentric tubes, the general notation given to different variants of the curved serpentine coil is CS-α-θ. The three variants are named as a cylindrical curved serpentine coil (α = 0°), conical curved serpentine coil (0° < α < 90°), and spiral curved serpentine coil (α = 90°). The fluid experiences a switching angle of 90° − α and 90° + α at the entrance and exit of every U-bend, respectively. The laminar flow of water in CS-α-θ coils (45° ≤ θ ≤ 270°, 0° ≤ α ≤ 90°) is simulated using ANSYS FLUENT version 20.2 for the range 500 ≤ Re ≤ 2000. The length-averaged Nu and f are found to decrease with an increase in either α or θ for the same mean radius Rm of concentric tubes. Secondary flow intensity is quantified using the parameter Se and is correlated with the flow and geometric parameters. Generalized correlations for predicting the average Nusselt number and friction factor for CS-α-θ coils are expressed as the sum of corresponding straight tube values and as a function of Se with a maximum deviation of ±8.5% and ±7%, respectively.
Outflow boundary condition of multiphase microfluidic flow based on phase ratio equation in lattice Boltzmann method
Authors: Zong Yi , Li Min , Wang Kai
Published: July 2021

This article proposes a new outflow boundary condition for the color gradient model in the multiphase lattice Boltzmann method. The boundary condition is based on the phase ratio equation and made use of the Zou–He boundary condition in single-phase flow. The boundary condition is provided in two-dimension-nine-velocity (D2Q9) and three-dimension-twenty-seven-velocity (D3Q27) schemes, for which an extension of the Zou–He boundary condition to D3Q27 is also derived and its correctness verified. Application cases, including two-phase parallel flows, droplet flows, T-junction flows, three-phase Janus droplet flows in two-dimensional (2D), and three-dimensional (3D) spaces, demonstrate the effectiveness of this new boundary condition, and the performance of a test case shows its improved pressure stability and mass conservation characteristics.
Universal flapping states of elastic fibers in modulated turbulence
Authors: Olivieri Stefano , Mazzino Andrea , Rosti Marco E.
Published: July 2021

We study the fully coupled dynamics between a fully developed turbulent flow and an ensemble of immersed flexible fibers. We vary the concentration of the suspension, the mechanical properties, and the length of the fibers in a vast parametric range. For all configurations, the fiber dynamics falls in only two possible dynamical states: (i) the fiber manifests its natural response to the flow forcing or (ii) its motion fully synchronizes to the hydrodynamic timescales of the turbulent flow. This scenario holds for both a dilute condition, where the carrier flow is not affected by the fluid–structure interaction, as well as in the case where the flow is substantially altered by the presence of immersed objects. Such a backreaction effect can be macroscopically modeled in terms of the mass fraction of the suspension. Our results can be readily extended to any elastic objects interacting with fluid turbulence.
Noise induced suppression of spiral waves in a hybrid FitzHugh–Nagumo neuron with discontinuous resetting
Authors: Rajagopal Karthikeyan , Jafari Sajad , Moroz Irene , Karthikeyan Anitha , Srinivasan Ashokkumar
Published: July 2021

A modified FitzHugh–Nagumo neuron model with sigmoid function-based recovery variable is considered with electromagnetic flux coupling. The dynamical properties of the proposed neuron model are investigated, and as the excitation current becomes larger, the number of fixed points decreases to one. The bifurcation plots are investigated to show the chaotic and periodic regimes for various values of excitation current and parameters. A N×N network of the neuron model is constructed to study the wave propagation and wave re-entry phenomena. Investigations are conducted to show that for larger flux coupling values, the spiral waves are suppressed, but for such values of the flux coupling, the individual nodes are driven into periodic regimes. By introducing Gaussian noise as an additional current term, we showed that when noise is introduced for the entire simulation time, the dynamics of the nodes are largely altered while the noise exposure for 200-time units will not alter the dynamics of the nodes completely.
A modified Oldroyd-B model for non-colloidal suspensions
Authors: Tanner Roger I.
Published: July 2021

Professor R. Byron Bird used Oldroyd models of rheological behavior over a span of around 50 years. In this paper, it is suggested that a modified Oldroyd-B model can also be used to describe the rheology of non-colloidal suspensions that have a viscoelastic matrix.
TaPCNA plays a role in programmed cell death after UV-B exposure in wheat (
Authors: Du Meiting , Zhang Ying , Chen Huize , Han Rong
Published: July 2021

Ultraviolet (UV)-B is a component of sunlight and shows a significant effect on DNA damage, which can be regulated by proliferating cell nuclear antigen (PCNA). The role of TaPCNA in wheat (Triticum aestivum L.) programmed cell death (PCD) under UV-B has not been investigated previously. Here, we explored the function of TaPCNA in wheat exposed to UV-B utilising Barley Stripe Mosaic Virus–virus-induced gene silencing (VIGS). The results showed that the expression of TaPCNA was downregulated, and curly wheat leaves with several spots were determined by VIGS. The growth rate and mesophyll cell length were significantly inhibited after TaPCNA was silenced. The activity of superoxide dismutase and the contents of soluble sugar and soluble protein decreased, whereas the activities of peroxidase and catalase and malondialdehyde content increased in TaPCNA-silenced and UV-B treatment groups. DNA laddering and propidium iodide staining results showed that DNA fragments and micronucleus accumulated after TaPCNA silencing with or without UV-B. Thus, TaPCNA participates in plant growth and DNA damage and PCD under UV-B. This study suggests an idea for the exploration of the function of certain genes in such complex wheat genomes and offers a theoretical basis to improve wheat agronomic traits.
What rules? Framing the governance of artificial agency
Authors: Gahnberg Carl
Published: July 2021

Artificial Intelligence (AI) is not new, but recent years have seen a growing concern about the technology’s political, economic and social impact, including debates about its governance. This paper describes how an analysis of the technology’s governance should build on the understanding of AI as the creation of artificial agents, and that the challenge that governance seeks to address is best understood as one of material agency. It describes how relevant rules can be systematically analyzed across different applications by considering the fundamental properties of artificial agents. The paper concludes by describing how the framework can be applied for further governance studies, and as a means to bridge insights across social science and technical perspectives on AI.
Hermetic chip-scale packaging using Au:Sn eutectic bonding for implantable devices
Authors: Szostak Katarzyna M , Keshavarz Meysam , Constandinou Timothy G
Published: July 2021

Advancements in miniaturisation and new capabilities of implantable devices impose a need for the development of compact, hermetic, and CMOS-compatible micro packaging methods. Gold-tin-based eutectic bonding presents the potential for achieving low-footprint seals with low permeability to moisture at process temperatures below 350 ∘C. This work describes a method for the deposition of Au:Sn eutectic alloy frames by sequential electroplating from commercially available solutions. Frames were bonded on the chip-level in the process of eutectic bonding. Bond quality was characterised through shear force measurements, scanning electron microscopy, visual inspection, and immersion tests. Characterisation of seals geometry, solder thickness, and bonding process parameters was evaluated, along with toxicity assessment of bonding layers to the human fibroblast cells. With a successful bond yield of over 70% and no cytotoxic effect, Au:Sn eutectic bonding appears as a suitable method for the protection of integrated circuitry in implantable applications.
Efficiency large deviation function of quantum heat engines
Authors: Denzler Tobias , Lutz Eric
Published: July 2021

The efficiency of small thermal machines is typically a fluctuating quantity. We here study the efficiency large deviation properties of two exemplary quantum heat engines, the harmonic oscillator and the two-level Otto motors. To this end, we analytically compute their joint characteristic functions for heat and work based on the two-projective-measurement approach. We investigate work–heat correlations within the respective engine cycles and find, for generic scale-invariant quantum heat engines, that work and heat are perfectly anticorrelated for adiabatic driving. In this limit, the effects of thermal as well as quantum fluctuations are suppressed, the large deviation functions are singular and the stochastic efficiency is equal to the macroscopic efficiency.
Crystallinity characterization of white matter in the human brain
Authors: Teich Erin G , Cieslak Matthew , Giesbrecht Barry , Vettel Jean M , Grafton Scott T , Satterthwaite Theodore D , Bassett Danielle S
Published: July 2021

Human brain tissue is a heterogeneous material, consisting of soft outer grey matter tethered internally by stiffer cords of white matter. These white matter tracts conduct electrical impulses between grey matter regions, thereby underpinning neuronal communication. Understanding the material properties of white matter is thus crucial for understanding brain function generally. Efforts to assess white matter microstructure are currently hampered by the inherent limitations of reconstruction by diffusion imaging. Techniques typically represent white matter structures with single scalars that are often difficult to interpret. Here, we address these issues by introducing tools from materials physics for the characterization of white matter microstructure. We investigate structure on a mesoscopic scale by analyzing its homogeneity and determining which regions of the brain are structurally homogeneous, or ‘crystalline’ in the context of materials physics. We find that crystallinity provides novel information and varies across the brain along interpretable lines of anatomical difference, with highest homogeneity in regions adjacent to the corpus callosum, a large interhemispheric tract. Furthermore, crystallinity is markedly reliable across iterative measurement, yet also varies between individual human volunteers, making it potentially useful for examining individual differences in white matter along several dimensions including sex and age. We also parcellate white matter into ‘crystal grains’, or contiguous sets of voxels of high structural similarity, and find overlap with a common atlas of distinct white matter areas. Finally, we characterize the shapes of individual diffusion signatures through another tool from materials physics—bond-orientational order parameters—to locate fiber crossings and fascicles. Our results provide new means of assessing white matter microstructure on multiple length scales, and open multiple avenues of future inquiry involving soft matter physics and neuroscience.
Evanescent wave induced polarization-insensitive self-organization of stratified single-negative materials
Authors: Cui Liyong , Yin Hang
Published: July 2021

Optical fields can induce optical forces between macroscopic objects, giving rise to different structures. Through rigorous calculation, we show that a collection of single negative slabs which possesses either negative permittivity or negative permeability (i.e. ε < 0, μ > 0 or ε > 0, μ < 0) in water can be self-organized into one-dimensional photonic crystals, due to the coupling of propagating wave and evanescent wave. We further demonstrated that the optical binding is irrespective of the polarization and angle of the incident plane wave. We call such a phenomenon—polarization-insensitive optical binding. We also demonstrate that polarization-insensitive optical binding can be achieved on microscale and millimeter scale. Polarization and angle insensitive band edge is the key to achieve polarization and angle insensitive optical binding. This work provides a new strategy to tailor the photonic crystals containing single negative materials towards the development of fine-tuning optical devices.
Markov chain Monte Carlo analyses of the flux ratios of B, Be and Li with the DRAGON2 code
Authors: De La Torre Luque P. , Mazziotta M.N. , Loparco F. , Gargano F. , Serini D.
Published: July 2021

Recent cosmic-ray measurements are challenging our models of propagation in the Galaxy. A good characterization of the secondary cosmic rays (B, Be, Li and sub-iron species) is crucial to constrain these models and exploit the precision of modern CR experiments. In this work, a Markov chain Monte Carlo analysis has been implemented to fit the experimental flux ratios between B, Be and Li and their flux ratios to the primary cosmic-ray nuclei C and O. We have fitted the data using two different parametrizations for the spallation cross sections. The uncertainties in the evaluation of the spectra of these secondary cosmic rays, due to spallation cross sections, have been taken into account by introducing scale factors as nuisance parameters in the fits, assuming that this uncertainty is mostly due to the normalization of the cross sections parametrizations. We have also tested two different formulations for the diffusion coefficient, which differ in the origin of the high energy hardening (∼ 200 GeV/n) of cosmic rays. Additionally, two different approaches are used to scale the cross sections, one based on a combined analysis of all the species (“combined” analysis) and the other reproducing the high energy spectra of the secondary-to-secondary flux ratios of Be/B, Li/B, Li/Be (“scaled” analysis). This allows us to make a better comparison between the propagation parameters inferred from the cross sections parametrizations tested in this work. This novel analysis has been successfully implemented using the numerical code DRAGON2 dedicated to cosmic-ray propagation to reproduce the cosmic-ray nuclei data up to Z=14 from the AMS-02 experiment.
In general, it is found that the ratios of Li favor a harder spectral index of the diffusion coefficient, but compatible with the other ratios inside the observed 2σ uncertainties. In addition, it is shown that, including these scale factors, the secondary-to-primary flux ratios can be simultaneously reproduced, obtaining that the scale factor associated to the cross sections of boron production is the lowest one, whereas that associated to Li production is the largest one.
Muon metrology and positioning: the POMME experiment
Authors: Procureur S. , Attié D. , Gomez H. , Lehuraux M. , Magnier P. , Mandjavidze I. , Mas P.
Published: July 2021

A muon metrology experiment is presented: two distant muon detection systems are used in coincidence to detect these particles originating from primary cosmic rays. The excellent spatial resolution of the Micromegas detectors allows for a precise relative positioning of the two instruments. The current setup can be used to monitor mid- or long-term deformations of a structure down to sub-millimeter resolution. It could also be employed to roughly position a distant structure with single muon detection, a typical example being an underground cavity whose position with respect to the surface is poorly known.
Construction and simulation bias study of the guide Tube Calibration System for JUNO
Authors: Guo Yuhang , Zhu Kangfu , Zhang Qingmin , Zhang Feiyang , Meng Yue , Liu Jianglai , Qu Eryuan
Published: July 2021

A Guide Tube Calibration System (GTCS) has been designed for the Jiangmen Underground Neutrino Observatory (JUNO), in order to measure the detector energy response near the outer radius of the active volume. Recently, a prototype system has been constructed and tested, and the calibration algorithm has also been studied to evaluate the risk when the simulation tuning and the error control fail.
In this paper, we first report its construction and the performance tests in the lab. Then the influence on the global energy measurement caused by the simulation bias of GTCS is discussed, in order to make sure the algorithm is qualified.
Local and non-local controls on seasonal variations in water availability and use by riparian trees along a hydroclimatic gradient
Authors: Sargeant Christopher I , Singer Michael Bliss
Published: July 2021

As global climate change continues to impact regional water cycles, we may expect further shifts in water availability to forests that create challenges for certain species and biomes. Lowland deciduous riparian forests are particularly vulnerable because tree species cannot migrate out of the stream corridor, and they rely on root zone water availability that is controlled by variations in both local climate conditions (e.g. precipitation, evaporation, and infiltration) and non-local hydroclimatic forcing (e.g. streamflow, snowmelt, recharge). To determine how the seasonal water source usage of riparian trees is controlled by local versus non-local variability in hydroclimatic regime, we reconstructed the seasonal oxygen isotope (δ
18
O) signature of water used by two riparian tree species with contrasting rooting depths, comprising ∼800 δ
18
O tree-ring cellulose measurements from 12 tree-level decadal time-series at sub-annual resolution (six samples per year), along a strong hydroclimatic gradient within the Rhône River basin, SE France. These results were evaluated alongside δ
18
O measurements made from potential endmember water sources and independent hydroclimatic metrics. Thus we characterize the seasonal evolution of both potential water availability at distinct rooting depths and tree water source use and investigate the generalized riparian tree response to seasonal variations in local versus non-local hydroclimatic forcing over a decade. We show: (a) distinct seasonal water use between species, based on differential access to groundwater; (b) substantial source switching in both species based on evolving water availability; and (c) that riparian trees are more dependent on locally controlled soil moisture with distance downstream, creating increased vulnerability to locally increasing temperatures. We also find that deeply rooted trees in lowland riparian floodplains are potentially vulnerable to climate change because of their high dependence on water supply from mountains. This effect is more pronounced downstream, where seasonal water table decline may lead to loss of water required for deeply rooted trees.
Autonomous redundancy system for auxiliaries of NPPs based on existing start-up reserve steamshops
Authors: Yurin V E
Published: July 2021

The method of using the start-up reserve steamshops installed at the NPP to improve the safety and economic efficiency of the plant was proposed in the article. Earlier, the author of the article proved on the basis of experimental data from the Balakovo NPP that a low-power steam turbine can provide power supply for the NPP’s own needs through the use of the core residual heat release. Such steam turbine can effectively work in conjunction with a start-up reserve steamshops in the normal mode to generate additional electricity to the power system and to provide a reliable reserve for NPP own needs in case of the station blackout. In the article, the characteristics of the known units corresponding to the developed system are presented, and the cooldown process based on the developed method is described.
Analysis of energy quality in power supply systems with grid-connected solar power plants
Authors: Leshtayev O V , Stushkina N A , Zaginaylov V I
Published: July 2021

The article presents an analysis of the quality of voltage at a consumer of electricity in power supply systems with a network solar power plant connected in parallel to the centralized network. The legislative base of the Russian Federation, regulating the construction and operation of grid solar power plants, requirements for the quality of energy in a centralized grid have been studied. The block diagram of the operating experimental solar power plant is presented. On the basis of this station, experimental studies of the influence of the operation of a solar power plant on the quality of energy at the consumer have been carried out. This study was carried out using a Fluke 345 power quality analyzer. The authors analyzed the experimentally obtained data on voltage changes and harmonic distortions at the consumer in two series of experiments (with a solar power plant in operation and with a solar power plant disconnected). On the basis of the analysis, conclusions were drawn about the reduction of peak voltage deviations at the consumer and a decrease in the total harmonic distortion factor when the solar power plant is operating. The relationship between voltage and harmonic distortion is described mathematically. Based on the results of the studies, conclusions were drawn about improving the quality of energy for an agricultural consumer when supplied with electricity from a grid solar power plant in parallel with a centralized grid.
Underground tunnel type PSPP
Authors: Liamasov A K , Biriulin M A , Denisov K E
Published: July 2021

The article discusses the main scheme and advantages of an underground tunnel-type pumped storage power plant (PSPP). Unlike traditional layouts of such stations, the upper and lower basins are located underground and formed by a single tunnel. A description of the design of the new station type and a method for calculating its main parameters were proposed. The analysis showed the limitations that must be taken into account when choosing the main hydraulic equipment for the tunnel-type underground PSPP. Based on the calculations, the optimal diameters of the tunnels were analyzed and identified to ensure the minimum construction period.
Trends in the formation of an alternative energy balance in Russia using information technologies during the climate crisis
Authors: Bogodukhova E S , Bobrova E O , Britvina V V , Zueva A S , Sorokin A Y
Published: July 2021

This work is devoted to the formation of a rational energy balance in Russia and its pragmatic management of alternative energy during the climate crisis using information technologies. The aim of the work is to study low-carbon development aimed at reducing the amount of CO2 emissions into the atmosphere, to stabilize climate change and prevent negative consequences. A comparative analysis of several countries has shown that renewable energy influences both the situation in the global energy market and the environmental situation of the country as a whole. The territorial study of sunshine in Russia has identified the regions where the transition to alternative energy sources for further energy supply is the most effective, and is able to ensure financial sustainability and tariff equalization, as well as an increase in the living standards of the population. Based on the results of the work done, the root causes of the lack of active implementation of renewable energy sources were identified and a profitable direction for the development of an alternative energy system for Russia was formed. The article is supplied with graphic materials and tables, as well as a detailed description of each stage of the study.
Distributed generation as a mechanism to improve the reliability and economic efficiency of electricity systems
Authors: Dolotin A I , Shifrin I O , Chernova I I , Kerimova O V , Sheshnitzan I N
Published: July 2021

The article assesses the application of distributed generation to meet the customer’s own needs for electricity and heat. Currently, the electric power industry is faced with many problems of functioning of electric power systems, which have a negative impact on the processes of transmission and distribution of electric energy to end users. These problems lead to decrease in reliability of power supply and economic efficiency of operation of enterprises. In order to solve the problems of increasing the reliability and economic efficiency of electric power systems the introduction of distributed generation is effective. The modes of electric power generation are considered. The paper also analyzes and identifies the features of the application of distributed generation to achieve the required indicators of reliability and economic efficiency of electric power systems.
Power supply system for electrical installations with electrical converters, grid, generator and solar sources
Authors: Lyapin V G , Leshtayev O V , Gafiev A E , Kolmurzina E V , Stushkina N A
Published: July 2021

Over the past decades, the range and functionality of power supplies has expanded and changed significantly. This is primarily due to the continuous desire to reduce the weight and size characteristics of the power supply, to increase their efficiency, to use modern economical pulse control methods, integrated microcircuits, etc.
Complex flue gas cleaning of thermal power plants
Authors: Protsko D S , Panov S Yu , Lobachova N N , Lavrov S V , Belozercev A S
Published: July 2021

Currently, there are significant emissions of pollutants from electric power facilities in our country. At the TPP, sulfur and nitrogen purification technologies are practically not used, most of the installed ash collectors operate with low efficiency and using outdated technology, and environmental indicators are significantly inferior to foreign analogues. At the same time, there is experience in the development and development on an industrial scale of various methods and tools that provide a significant reduction in emissions of particulate matter, sulfur oxides and nitrogen. The article considers an example of such a technology. For particle cleaning, a ceramic high-temperature filter with a catalytic coating is used to selectively remove nitric oxide when interacting with carbomide. The sulfur is removed by chemical neutralization with a lime sorbent.
Study of the influence of the mass content of deposited cobalt in Co/25%ZrO2·SiO2 catalysts on the main parameters of the process of synthesis of liquid and solid hydrocarbons by the Fischer-Tropsch method
Authors: Kraetskaya O F , Glinnik S V , Udovenko E V , Bykova I V
Published: July 2021

In this paper, the influence of the mass content of deposited cobalt (from 10 to 50 wt.%) in samples of Co/25%ZrO2·SiO2 on the main indicators of the synthesis of liquid and solid hydrocarbons from a mixture of carbon monoxide and hydrogen at atmospheric pressure. It is established that all the studied catalysts exhibit high activity in this process. The best performance and selectivity indicators for liquid and solid carbonic hydrogens were obtained in the presence of a catalyst sample containing 40 wt. % of the applied Co. The yield of C5 + hydrocarbons at 85% of the synthesis gas conversion on it was 160 g/m3, and the selectivity of their formation was 90%.
Oil shale of the Middle Volga region: composition, structure, energy properties
Authors: Korolev E A , Eskin A A , Korolev A E , Barieva E R , Khuzin I A
Published: July 2021

The article presents the results of the Volga oil shale study in the territory of Tatarstan and the Ulyanovsk region. It is shown that shales are polymineral rocks of complex composition. The main valuable component is organic matter (kerogen), formed from the products of aquabionts fossilization. Ash components are represented by clay minerals, clastic fragments of mineral grains, calcareous fragments of organic residues, and diagenetic pyrite. Organic matter has a complex structure. The predominant fractions are light and medium hydrocarbons boiling out in the temperature range 150-560°C. In smaller amounts, heavy fractions are present, which are released at temperatures of 560-620°C. The heat capacitance of oil shale ranges from 1607 to 9052 J/g. Loss of shale mass can range from 18.0 to 25.0% of the original sample. According to the summary valuable and genetic indicators, the Volga oil shale belongs to the humus-sapropel type; low-calorie in heat of combustion terms; polysulphide in terms of sulfur content; aluminosilicate-carbonate in terms of the prevalence of oxides in ash.
Assessment of the geological factors influence on the oil-productive of terrigenous reservoirs of the Vereyian horizon of the Melekess depression
Authors: Korolev E A , Eskin A A , Khuzina A F , Barieva E R , Ilaeva A A
Published: July 2021

The article presents study results of terrigenous reservoirs of the Vereiskian horizon of Tatarstan. The sandstones and silty sandstones are composed by grains of quartz, feldspars, clay minerals and organic remains cemented with calcite. Rocks were formed under the conditions of marine paleobasin coastal part with normal salinity. The migrated aggressive solutions partially leached out the carbonate cement from sediment, realizing the reservoir-filtration potential inherent in rocks. The oil fluids that filled the pore space practically did not interact in any way with the mineral skeleton of terrigenous reservoirs at the chemical level. Thus, the influence of the rocks mineral component on the properties of oils is completely excluded. In oil-saturated reservoirs, from which good oil inflows are obtained, light fractions of hydrocarbons prevail, boiling away at temperatures of 200-320°C. In the reservoir rocks, from where the watered oils are obtained, there are medium and heavy fractions of hydrocarbons, boiling at temperatures of 320-450°C. In unproductive sandy reservoirs with immobile viscous oil, only heavy fractions of hydrocarbons, which boiling at temperatures above 450°C, prevail. Thus, the oil recovery of terrigenous reservoirs is determined not by the composition of host rocks, but by the degree of oils oxidation contained in them.
Synthesis and antioxidant properties of novel 1,2,4-triazoles with 2,6-di-tert-butylphenol fragments
Authors: Primerova O V , Koshelev V N , Sabitov E R
Published: July 2021

This work describes the synthesis of novel derivatives of 1,2,4-triazole containing a hindered phenol fragment. Influence of the obtained compounds on the thermal-oxidative stability of the sealing liquid AG-4I was investigated. Triazolothiazoles with long alkyl substituents were found to exhibit better antioxidant properties compared to Agidol-1.
Method for measuring the active electrical resistance of a diffusion flame when burning liquid combustible substances
Authors: Stolyarov D V , Koroleva T I , Mikhailov K A , Shaposhnik D S , Ivachef M A
Published: July 2021

The article is devoted to the problem of studying the electrical properties of a flame in a fire. The article discusses a method for measuring the active electrical resistance of a diffusion flame when burning liquid combustible substances. The dependence of the electrical resistance of the flame torch on the geometric dimensions of the combustion zone and on the average volumetric temperature of the flame torch in the mode of the laminar flow of the combustible mixture has been established. An empirical dependence has been obtained, which makes it possible to calculate the value of the electrical resistance of the flame.
Information and communication technologies in environmental monitoring of climate change
Authors: Makhonko N I , Belousov S A , Tarasova E A , Plotnikova Yu A
Published: July 2021

The article is devoted to the problems of the Earth’s climate change as an object of environmental protection and an object of international cooperation. In the implementation of environmental and legal support for climate preservation by the countries of the European Union and the Russian Federation, characteristic features are manifested, which are due to the similarity of specific tasks. The aim of the study is to analyze the prospects for the development of the institute of environmental monitoring associated with the dynamic implementation of the latest information and communication methods and systems in the implementation of mechanisms that prevent and stabilize changes in the Earth’s climate. The article analyzes the main program and legal documents of Denmark, Germany, France and Russia, their variability in determining special approaches to the study of climate change. Attempts to create an adequate system of convergence of national and international legal regulation in order to determine modern legal approaches to the problems of global warming have been studied and discussed in detail. Each of the represented countries has a national strategy for achieving carbon neutrality in the context of creating a circulating model of the modern economy. It is noted that for most of the topical issues, these strategies have common approaches: scientifically based methods of environmental monitoring, the introduction of innovative digital technologies and science-intensive information and communication methods and systems.
Social factors determining the social danger of acts in the sphere of functioning of objects of the fuel and energy complex
Authors: Provodina E V
Published: July 2021

The study showed that an active and continuous fight against harmful effects on the environment caused by the operation of the fuel and energy complex facilities is carried out at various levels, including technological solutions, policy formation in the industry in question, as well as protection mechanisms for specific natural objects. An analysis of the methods available in science to minimize such consequences has shown that only an integrated approach to the situation will make it possible to achieve positive results. In this connection, the purpose of the study is to identify the factors that determine the social danger of acts in the field of the functioning of the objects of the fuel and energy complex, as the basis of preventive mechanisms in the field of environmental protection. The advantage of the presented approach consists in legal counteraction based on a combination of social factors, including an assessment of the potential danger emanating from the objects under consideration. The study of these factors is carried out, to a greater extent, in the context of criminal-legal prevention of reckless acts in the field of environmental safety, which determines its practical and theoretical significance.
Formation of mechanisms for creating innovative national polygons
Authors: Tretyakova L A , Azarova N A , Lavrikova N I , Opara M V , Tsvyrko A A
Published: July 2021

Currently, the issues of environmental protection and conservation are becoming very acute. The development strategy of the world community is determined by the UN Sustainable Development Goals. According to this document, one of the priorities is to eliminate the harmful effects of carbon fuel emissions. In the world, about 80% of the energy produced is produced by burning carbon, which leads to the release of greenhouse gases into the atmosphere. Annual CO2 emissions reach 33.1 billion tons, causing irreparable damage to the environment. Our nature will continue to develop and evolve under these conditions, but the drastic climate change, global warming, and the mutation of flora and fauna are tasks that require immediate solutions. As a solution to these problems, we can offer the use of alternative energy sources. They represent promising ways to obtain, transfer and use energy from renewable sources, reducing the risk of harm to the environment. Also, to reduce harmful CO2 emissions into the atmosphere, methods for reducing greenhouse gas emissions are proposed, including carbon dioxide sequestration technologies, which are implemented in the form of CC (U) S (carbon capture, utilization and storage) projects. Another solution to the tasks set can be the creation of carbon landfills and farms that will allow us to develop technologies for monitoring carbon emissions and runoff.