bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integration of an optical FBG sensor into a nuclear magnetic resonance core flooding system
Authors: Esteban Lionel , Giwelli Ausama , Kovalyshen Yevhen 
Published: April 2022

Abstract
A new platen was designed and developed for a nuclear magnetic resonance (NMR) core flooding cell for the integratation of fibre Bragg grating (FBG) strain sensors. The platen is made from carbon fibre material with a special channel to insert the FBG inside the cell, and it is compatible with an NMR overburden system (i.e. no metal, and also resistant to pressure, temperature and reactive chemicals) to allow, for example, advanced chemical experiments. This development has allowed us to acquire both fluid dynamics behaviour, from NMR, and deformation/elastic properties, from FBG sensors, during NMR core flooding experiments for advanced hydro-mechanical-chemical coupling characterisation. Generally, pore fluid redistribution occurs while changing the surrounding stress and/or temperature conditions of the tested material, and will generate elastic and geomechanical responses. The impact of rock–fluid interactions during NMR core flooding has not been evaluated until now, mainly due to technical limitations. Fortunately, the FBG sensing technique is a localised/discreet micro-strain gauge (8 mm long and 125 micro thick), and it is applicable to the monitoring of pseudo-tomography during core flooding experiments. We recently managed to attach eight FBG sensors on a carbonate rock plug to monitor strain alteration during brine imbibition under 800 psi confining pressure. The results validate the ability of the FBG sensors to track mechanical strength alterations due to pore pressure changes and also to detect waterfront velocity during injection. The integration of FBG sensors into the NMR core flooding system has added a new capability to the NMR overburden system, enabling it to simultaneously monitor material deformation with FBG sensors during pressure/temperature alterations as a first basic application.
Superballistic and superdiffusive scaling limits of stochastic harmonic chains with long-range interactions
Authors: Suda Hayate 
Published: April 2022

Abstract
We consider one-dimensional infinite chains of harmonic oscillators with random exchanges of momenta and long-range interaction potentials which have polynomial decay rate |x|−θ
, x → ∞, θ > 1 where

x
∈
Z

is the interaction range. The dynamics conserve total momentum, total length and total energy. We prove that the systems evolve macroscopically on superballistic space-time scale

(

y

ε

−
1

,
t

ε

−

θ
−
1

2

)

when 1 < θ < 3,

(

y

ε

−
1

,
t

ε

−
1

−
log

(

ε

−
1

)

−
1

)

when θ = 3, and hyperbolic space-time scale (yɛ
−1, tɛ
−1) when θ > 3. Combining our results and the results in (Suda 2021 Ann. Inst. Henri Poincare B 57 2268–2314), we show the existence of two different space-time scales on which the systems evolve. In addition, we prove the fluctuations of the normal modes of the superballistic wave equation, which are analogues of the Riemann invariants and capture fluctuations along the characteristics. For the normal modes, the space-time scale is superdiffusive when 2 < θ ⩽ 4 and diffusive when θ > 4.
On the structure of periodic eigenvalues of the vectorial p-Laplacian
Authors: Liu Changjian , Zhang Meirong 
Published: April 2022

Abstract
In this paper we will solve an open problem raised by Manásevich and Mawhin twenty years ago on the structure of the periodic eigenvalues of the vectorial p-Laplacian. This is an Euler–Lagrangian equation on the plane or in higher dimensional Euclidean spaces. The main result obtained is that for any exponent p other than 2, the vectorial p-Laplacian on the plane will admit infinitely many different sequences of periodic eigenvalues with a given period. These sequences of eigenvalues are constructed using the notion of scaling momenta we will introduce. The whole proof is based on the complete integrability of the equivalent Hamiltonian system, the tricky reduction to two-dimensional dynamical systems, and a number-theoretical distinguishing between different sequences of eigenvalues. Some numerical simulations to the new sequences of eigenvalues and eigenfunctions will be given. Several further conjectures towards to the panorama of the spectral sets will be imposed.
Global well-posedness for axisymmetric MHD equations with vertical dissipation and vertical magnetic diffusion
Authors: Wang Peng , Guo Zhengguang 
Published: April 2022

AbstractIn this paper, the unique global strong axisymmetric solutions for the incompressible MHD equations with only vertical dissipation and vertical magnetic diffusion are established, where no smallness assumptions on the initial data are required. One of the key ingredients of the analysis is to obtain higher-order regularity estimates for velocity and magnetic fields, where the axisymmetry of the solutions and some newL2energy estimates play an important role.
From quantum speed limits to energy-efficient quantum gates
Authors: Aifer Maxwell , Deffner Sebastian 
Published: April 2022

Abstract
While recent breakthroughs in quantum computing promise the nascence of the quantum information age, quantum states remain delicate to control. Moreover, the required energy budget for large scale quantum applications has only sparely been considered. Addressing either of these issues necessitates a careful study of the most energetically efficient implementation of elementary quantum operations. In the present analysis, we show that this optimal control problem can be solved within the powerful framework of quantum speed limits. To this end, we derive state-independent lower bounds on the energetic cost, from which we find the universally optimal implementation of unitary quantum gates, for both single and N-qubit operations.
Ambient forcing: sampling local perturbations in constrained phase spaces
Authors: Büttner Anna , Kurths Jürgen , Hellmann Frank 
Published: April 2022

Abstract
Ambient forcing is a novel method to sample random states from manifolds of differential-algebraic equations (DAE). These states can represent local perturbations of nodes in power systems with loads, which introduces constraints into the system. These states must be valid initial conditions to the DAE, meaning that they fulfill the algebraic equations. Additionally, these states should represent perturbations of individual variables in the power grid, such as a perturbation of the voltage at a load. These initial states enable the calculation of probabilistic stability measures of power systems with loads, which was not yet possible, but is important as these measures have become a crucial tool in studying power systems. To verify that these perturbations are network local, i.e. that the initial perturbation only targets a single node in the power grid, a new measure, the spreadability, related to the closeness centrality (Freeman 1978 Soc. Netw.
1 215–39), is presented. The spreadability is evaluated for an ensemble of typical power grids. The ensemble depicts a set of future power grids where consumers, as well as producers, are connected to the grid via inverters. For this power grid ensemble, we additionally calculate the basin stability (Menck et al 2013 Nat. Phys.
9 89–92) as well as the survivability (Hellmann et al 2016 Sci. Rep.
6 29654), two probabilistic measures which provide statements about asymptotic and transient stability. We also revisit the topological classes, introduced in (Nitzbon et al 2017 New. J. Phys.
19 033029), that have been shown to predict the basin stability of grids and explore if they still hold for grids with constraints and voltage dynamics. We find that the degree of the nodes is a better predictor than the topological classes for our ensemble. Finally, ambient forcing is applied to calculate probabilistic stability measures of the IEEE 96 test case (Grigg et al 1999 IEEE Trans. Power Syst.
14 1010–20).
Landau parameters and entrainment matrix of cold stellar matter: effect of the symmetry energy and strong magnetic fields
Authors: Pais Helena , Ivanytskyi Oleksii , Providência Constança 
Published: April 2022

Abstract
Nuclear matter properties based on a relativistic approach suitable for the description of multi-component systems are calculated. We use a set of nuclear relativistic mean-field models that satisfy acceptable nuclear matter properties and neutron star observations. The effects of the density dependence of the symmetry energy and of the Landau quantization due to the presence of a strong external magnetic field are discussed. Properties such as the proton fraction, the Landau mass, Landau parameters and entrainment matrix, the adiabatic index and speed of sound are calculated for cold β-equilibrium matter. A large dispersion on the calculated properties is obtained at two to three times saturation density ρ0
. The proton Landau mass can be as low as one third of the vacuum nucleon mass at 2-3 ρ0
. Similar effects are obtained for the Landau parameters, in particular, the ones involving protons, where the relative dispersion of F0
pp
and F1
pp
is as high as 30% to 50% at 2-3 ρ0
. These parameters are particularly sensitive to the symmetry energy. The effect of the magnetic field on the nuclear properties is small for fields as high as 1018G except for a small range of densities just above the crust-core transition. Tables with the EoS, and the parameters, are provided in the supplementary data section.
Detection and Classification of Potential Caves on the Flank of Elysium Mons, Mars
Authors: Sharma Ravi , Srivastava Neeraj 
Published: April 2022

Abstract
Martian caves have revived interest in the field of subsurface exploration because they are the potential destinations for future human habitats and astrobiological research. There are many pits on Mars, but some of them look like collapsed cave roofs. These special pits are formed by the collapse of surface materials into the subsurface void spaces. The signature of life is probable in a subsurface cave on Mars as the subsurface environment can protect life from the harsh and dangerous radiation environment of the surface. In a cave, there may be an abundance of minerals, fluids, and other key resources. Therefore, locating the access point of the subsurface cave is essential and crucial for formulating plans for robotic/human explorations of the Red Planet, Mars. We have used remote sensing data from Mars Reconnaissance Orbiter (MRO; NASA), Mars Global Surveyor (MGS; NASA), and Mars Odyssey (NASA) for identifying, mapping, and classifying selected special pit candidates on the flank of Elysium Mons, Mars. A total of 32 special pit candidates has been identified and classified based upon morphology and geological context. Out of these, 26 are newly discovered ones. The thermal behavior of 23 special pit candidates confirms that the special pits are radiating heat energy at nighttime, similar to potential caves. Also, cave entrances have been detected in nine candidates using data from the HiRISE camera onboard MRO. These sites could be important destinations for future robotic/human exploration and the search for life on Mars.
Can Turbulent, High-density Gas Form Stars in Molecular Clouds: A Case Study in Ophiuchus
Authors: Jiao Sihan , Wu Jingwen , Ruan Hao , Lin Yuxin , Tsai Chao-Wei , Feng Linjing 
Published: April 2022

Abstract
Star formation is governed by the interplay between gravity and turbulence in most of molecular clouds. Recent theoretical works assume that dense gas, whose column density is above a critical value in the column density probability distribution function (N-PDF), where gravity starts to overcome turbulence, becomes star-forming gas and will collapse to form stars. However, these high-density gases will include some very turbulent areas in the clouds. Will these dense but turbulent gases also form stars? We test this scenario in Ophiuchus molecular cloud using N-PDF analysis and find that at least in some regions, the turbulent, dense gas is not forming stars. We identified two isolated high-density structures in Ophiuchus, which are gravitationally unbound and show no sign of star formation. Their high densities may come from turbulence.
Global gyro-kinetic study of magnetic shaping effects on linear trapped electron mode instability in normal/reversed magnetic shear plasmas
Authors: Wang Wei , Imadera Kenji , Seto Haruki , Yagi Masatoshi 
Published: April 2022

Abstract
A linear δf version of the gyro-kinetic Vlasov code GKNET (Gyro-Kinetic Numerical Experiment of Tokamak) is extended to the global cylindrical coordinates (R, φ, Z) and includes the kinetic electron response, to study the shaping effect on linear drift-wave instabilities in Tokamak plasmas. Cross-verifications are performed between three GKNET versions that use different electron models, i.e. the adiabatic electron model, hybrid electron model (only trapped electrons are calculated kinetically) and full-kinetic electron model (all electrons are calculated kinetically). A destabilizing effect of non-adiabatic passing electrons is observed in the full-kinetic case for the ion temperature gradient (ITG) mode in the short wavelength region and the trapped electron mode (TEM). The ion-to-electron mass ratio and the electron–electron collisionality have weak impacts on the destabilization of ITG/TEM. Utilizing magnetohydrodynamic equilibria designed with normal and reversed magnetic shear (NS and RS), the characteristics of linear TEMs and the corresponding impact of plasma shaping are studied based on the GKNET code with full-kinetic electrons. Due to the change in temperature/density gradient and magnetic shear either measured locally in the low field side (LFS) or averaged over the flux surface, plasma shaping shows different impacts on linear TEMs in NS and RS configurations. For the elongation κ, the increase in κ always stabilizes linear TEMs due to the reduction in the effective profile gradient over the flux surface. For the triangularity δ, in the NS case, the change in δ shows weak dependence on TEM linear growth rates due to the balance between variations of profile gradients and magnetic shear in the LFS. In the RS case, local magnetic shear in the peak gradient region is nearly zero. Thus, the variation in local profile gradient plays a dominant role on the linear growth in a plasma shaping scan. Consequently, the negative triangularity (δ < 0) has a destabilizing effect on the linear TEMs in the RS configuration mainly due to the upshift in local profile gradient in the LFS.
High speed visual insect swarm tracker (Hi-VISTA) used to identify the effects of confinement on individual insect flight
Authors: Ahmed Ishriak , Faruque Imraan A 
Published: April 2022

Abstract
Individual insects flying in crowded assemblies perform complex aerial maneuvers by sensing and feeding back neighbor measurements to small changes in their wing motions. To understand the individual feedback rules that permit these fast, adaptive behaviors in group flight, both experimental preparations inducing crowded flight and high-speed tracking systems capable of tracking both body motions and more subtle wing motion changes for multiple insects in simultaneous flight are needed. This measurement capability extends tracking beyond the previous focus on individual insects to multiple insects. This paper describes an experimental preparation that induces crowded insect flight in more naturalistic conditions (a laboratory-outdoor transition tunnel) and directly compares the resulting flight performance to traditional flight enclosures. Measurements are made possible via the introduction of a multi-agent high speed insect tracker called Hi-VISTA, which provides a capability to track wing and body motions of multiple insects using high speed cameras (9000–12 500 fps). Processing steps consist of automatic background identification, data association, hull reconstruction, segmentation, and feature measurement. To improve the biological relevance of laboratory experiments and develop a platform for interaction studies, this paper applies the Hi-VISTA measurement system to Apis mellifera foragers habituated to transit flights through the transparent transition environment. Binary statistical analysis (Welch’s t-test, Cohen’s d effect size) of 95 flight trajectories is presented, quantifying the differences between flights in an unobstructed environment and in a confined tunnel volume. The results indicate that body pitch angle, heading rate, flapping frequency, and vertical speed (heave) are each affected by confinement, and other flight variables show minor or statistically insignificant changes. These results form a baseline as swarm tracking and analysis begins to isolate the effects of neighbors from environmental enclosures, and improve the connection of high speed insect laboratory experiments to outdoor field experiments.
Association of ambient ozone exposure with anxiety and depression among middle-aged and older adults in China: exploring modification by high temperature
Authors: Shi Wanying , Li Tiantian , Zhang Yi , Sun Qinghua , Chen Chen , Fang Jianlong , Du Peng , Tang Song , Wang Qiong , Wang Jiaonan , Han Jingxiu , Hu Xiaojian , Shi Xiaoming 
Published: April 2022

Abstract
Anxiety and depression are severe public health problems worldwide. The effects of ozone exposure on anxious and depressive symptoms remain largely unknown, especially in China. We evaluated the associations between ozone exposure and depression and anxiety among middle-aged and older adults across China. A multi-center community-based repeated measurement study among middle-aged and older adults was conducted from 2017 to 2018 in 11 provinces in China. The status of depression and anxiety was measured using Patient Health Questionnaire-9 (PHQ-9) and the generalized anxiety disorder seven-item (GAD-7) scale at the cut-off point of five, respectively. Concentrations of multiple ozone metrics were collected from real-time monitoring stations. The multilevel logistic regression model with random intercept was used to evaluate the effects of ambient ozone on anxiety and depression over different exposure windows. After adjusting for potential confounders, a 10 μg /m3 increase in the three months moving average of ozone was associated with the risk of anxiety [odds ratio (OR) = 1.25; 95% confidence interval (CI): 1.15; 1.37] and depression (OR = 1.17; 95% CI: 1.08; 1.27). A significantly positive modification effect of temperature on associations between ozone and anxiety was also found, while there is no interaction for depression. Exposure-response curves showed that there may be a threshold for the effect of ozone exposure on anxiety and depression over the three months moving average concentrations, with similar patterns observed at different temperature levels. People over 65 years old were at significantly higher risks of ozone-associated depression, while anxiety was more strongly associated with ozone in hypertensive patients. Our study supports the theory that anxiety and depression is associated with mid-term ozone exposure in China, and temperatures significantly enhanced their associations. These findings may have significant implications for promoting prevention activities regarding mental disorders and approaches in reducing the disease burden by simultaneously controlling air pollution and mitigating climate change.
Black carbon dominated dust in recent radiative forcing on Rocky Mountain snowpacks
Authors: Gleason Kelly E , McConnell Joseph R , Arienzo Monica M , Sexstone Graham A , Rahimi Stefan 
Published: April 2022

Abstract
The vast majority of surface water resources in the semi-arid western United States start as winter snowpack. Solar radiation is a primary driver of snowmelt, making snowpack water resources especially sensitive to even small increases in concentrations of light absorbing particles such as mineral dust and combustion-related black carbon (BC). Here we show, using fresh snow measurements and snowpack modeling at 51 widely distributed sites in the Rocky Mountain region, that BC dominated impurity-driven radiative forcing in 2018. BC contributed three times more radiative forcing on average than dust, and up to 17 times more at individual locations. Evaluation of 2015–2018 archived samples from most of the same sites yielded similar results. These findings, together with long-term observations of atmospheric concentrations and model studies, indicate that BC rather than dust has dominated radiative forcing by light absorbing impurities on snow for decades, indicating that mitigation strategies to reduce radiative forcing on headwater snow-water resources would need to focus on reducing winter and spring BC emissions.
Technology comparison for green hydrogen production
Authors: Ourya I , Abderafi S 
Published: April 2022

Abstract
Because of greenhouse gas emissions generated by fossil fuels, it has become essential to find non-polluting alternatives. Hydrogen is generally produced from the steam methane reforming (SMR) process which generates a lot of greenhouse gases. However, there are many other processes to produce hydrogen that are cleaner and should be of interest. This study aims at comparing different existing technologies to produce hydrogen in a clean and non-polluting way, in particular biological and thermochemical processes from biomass and water splitting processes. Their comparison is made by analyzing several parameters such as the type of raw materials, energy sources, efficiency, waste generation, CO2 emissions and, hydrogen production rate. Among the biological processes to produce hydrogen from biomass, dark fermentation seems to be the best due to its high production efficiency. Thermochemical processes are also interesting because of their maturity, but they generate a lot of waste such as tar and ashes. Water splitting processes coupled with renewable energy have the advantage of being zero greenhouse gas generating. The electrolysis is the best from the point of view of production efficiency which reaches 80%.
Prospects for technological development of grain production in Ukraine
Authors: Cheremisina Svetlana , Rossokha Vladimir , Salo Inna , Mohilova Marina , Romanchenko Natalia 
Published: April 2022

Abstract
The article examines the problems of technological support for the production of grain crops and the development of the grain industry in Ukraine. A retrospective analysis of the dynamics of the yield of grain crops and the main food crop - wheat in Ukraine is presented. The necessity of improving agrotechnological methods and introducing zoned varieties of agricultural crops due to the differentiation of climatic conditions necessary for the development of agriculture on the territory of Ukraine has been proved. A factorial analysis of the effect of intensification on the yield and efficiency of growing winter wheat has been carried out, a direct dependence of wheat yield on production costs and an inverse relationship between profitability and production costs have been established. The essence and advantages of using No-till technologies that do not require preliminary preparation of the field for sowing grain crops are disclosed. Modern trends in the development of technologies in agriculture in Ukraine are presented. The advantages of using various models of intensive technologies aimed at maximizing the realization of the potential of varieties and hybrids of grain crops are disclosed. A comparative characteristic of the elemental costs of growing winter wheat with high-cost and resource-saving technologies is given. The system of indicators for evaluating the economic efficiency of methods for improving the technological support of the production of grain crops is substantiated. Key words: technology, crops, intensification, productivity, technological operation, resources.