bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of data availability and pseudo‐measurement synthesis on distribution system state estimation
Authors: Zufferey Thierry , Hug Gabriela
Published: January 2021

The influence of the advanced metering infrastructure (AMI) set‐up and of the related modelling of pseudo‐measurements on the accuracy of state estimation (SE) in distribution grids, especially at the low‐voltage level, is studied herein. A comprehensive sensitivity analysis is carried out that accounts for the type, the penetration level, and the placement of the metering devices that compose state‐of‐the‐art AMIs. Special care is given to the synthesis of active and reactive power pseudo‐measurements, which substantially impacts the estimation of peak values. Although crucial for system operators, peak values are very often neglected in the SE literature. For that purpose, this study promotes realistic approaches to generate synthetic load profiles and relies on evaluation metrics that are not purely based on the point‐wise precision but consider the statistical properties of the SE outcomes. This is tested on an actual 971‐bus distribution grid with the corresponding smart meter data and is evaluated with respect to the accuracy of active and reactive power injections, bus voltages, and line loadings.
Reduction of Grain Loss During Harvesting Due to the Rational Distribution of Vehicles
Authors: Esin Konstantin , Bodrov Andrei , Lomakin Denis , Kulev Maxim , Kulev Andrew
Published: January 2021

The paper deals with the mathematical model of the rational distribution of vehicles, which allows attaching them to a group of combine harvesters during harvesting, depending on the carrying capacity of vehicles, the productivity of combine harvesters and the capacity of grain storage facilities. In addition, it presents a formula which allows determining the required number of vehicles that will deliver grain from a group of combine harvesters. Further the article presents calculations of routes of vehicles movement and determination of the required number of vehicles de-pending on the carrying capacity of one of the operating agricultural organizations.
The Accuracy of Smartphone Sound Level Meter Applications (SLMAs) in Measuring Sound Levels in Clinical Rooms
Authors: Serpanos Yula C. , Schoepflin Janet R. , Cox Steven R. , Davis Diane
Published: January 2021

Abstract Background The accuracy of smartphone sound level meter applications (SLMAs) has been investigated with varied results, based on differences in platform, device, app, available features, test stimuli, and methodology. Purpose This article
determines the accuracy of smartphone SLMAs with and without calibration of external and internal microphones for measuring sound levels in clinical rooms. Research Design Quasi-experimental research design comparing the accuracy of two smartphone SLMAs with and without calibration
of external and internal microphones. Data Collection and Analysis Two iOS-based smartphone SLMAs (NIOSH SLM and SPL Meter) on an iPhone 6S were used with and without calibrated external and internal microphones. Measures included: (1) white noise (WN) stimuli from 20 to 100 dB
sound pressure level in a sound-treated test booth and (2) sound levels in quiet in four nonsound-treated clinical rooms and in simulated background sound conditions using music at 45, 55, and 80 dBA. Chi-square analysis was used to determine a significant difference (p ≤ 0.05)
in sound measures between the SLMAs and a Type 1 SLM. Results Measures of WN signals and room sound level measures in quiet and simulated background sound conditions were significantly more accurate at levels ≥ 40 dBA using the SLMAs with calibrated external and internal
microphones. However, SLMA measures with and without calibration of external and internal microphones overestimated sound levels < 40 dBA. Conclusion The SLMAs studied with calibrated external or internal microphones are able to verify the room environment
for audiologic screening at 1,000, 2,000, and 4,000 Hz at 20 dB hearing level (American Academy of Audiology and American Speech-Language-Hearing Association) using supra-aural earphones (American National Standards Institute S3.1‐1999 [R2018]). However, the tested SLMAs
overestimated low-level sound < 40 dBA, even when the external or internal microphones were calibrated. Clinicians are advised to calibrate the microphones prior to using measurement systems involving smartphones and SLMAs to measure room sound levels and to monitor
background noise levels throughout the provision of clinical services.
Impacts of atomic and magnetic configurations on the phase stability of Fe–Pd shape memory alloys: A first-principles study
Authors: Li Chun-Mei , Yang Shun-Jie , Zhang Yang , Huang Ren-Zhong
Published: January 2021

The effects of local atomic and magnetic configurations on the phase stability and elastic property of the face-centered cubic (fcc) and two body-centered tetragonal [face-centered tetragonal (fctI) and fctII, with 0.9<c/a<1 and 0.71<c/a<0.9, respectively, in the fct unit cell] phases of Fe1−xPdx (0.28≤x≤0.34) shape memory alloys are systematically investigated by using the first-principles exact muffin-tin orbital method in combination with the coherent potential approximation. It is shown that, considering four types of atomic configurations in a fcc unit cell, the two with one random sublattice are both preferable in each x below 300 K. When T=300 K, the one with three random sublattices also changes to be stabilized for x≤0.30, whereas that with four random sublattices becomes stable in most of these alloys until T≥600K. Upon tetragonal distortions, in these fully disordered alloys, both the fctI and fctII phases are unstable. The fctI phase is found for 0.29≤x≤0.33, having only the configuration with one random sublattice on the same layer with the Pd site in the unit cell, whereas the fctII phase is obtained for x≤0.30, possessing all the configurations with one, two, and three random sublattices. These results representing the phase diagram of these alloys, their determined equilibrium lattice parameters, and elastic constants of the three phases at 0 K are in line with the experimental and theoretical data, and their estimated structural (TM) and magnetic (TC) transition temperatures are also close to the experimental data. Adding 4% magnetic disorder in Fe0.70Pd0.30, the fctII structure is effectively prevented, whereas the thermoelastic martensitic transformation of fcc–fctI can still be retained at 0 K.
Accurate DMBE potential-energy surface for CNO(2A″) and rate coefficients in C(3P)+NO collisions
Authors: Alves M. O. , Gonçalves C. E. M. , Braga J. P. , Mota V. C. , Varandas A. J. C. , Galvão B. R. L.
Published: January 2021

A realistic double many-body expansion potential energy surface (PES) is developed for the 2A″ state of the carbon–nitrogen–oxygen (CNO) system based on MRCI-F12/cc-pVQZ-F12 ab initio energies. The new PES reproduces the fitted points with chemical accuracy (root mean square deviation up to 0.043 eV) and explicitly incorporates long range energy terms that can accurately describe the electrostatic and dispersion interactions. Thermal rate coefficients were computed for the C(3P) + NO(2Π) reaction for temperatures ranging from 15 K to 10 000 K, and the values are compared to previously reported results. The differences are rationalized, and the major importance of long range forces in predicting the rate coefficients for barrierless reactions is emphasized.
Sublattice mixing in Cs2AgInCl6 for enhanced optical properties from first-principles
Authors: Kumar Manish , Jain Manjari , Singh Arunima , Bhattacharya Saswata
Published: January 2021

Lead-free double perovskite materials (viz., Cs2AgInCl6) are being explored as stable and nontoxic alternatives of lead halide perovskites. In order to expand the optical response of Cs2AgInCl6 in the visible region, we report here on the stability, electronic structure, and optical properties of Cs2AgInCl6 by sublattice mixing of various elements. We have employed a hierarchical first-principles-based approach starting from density functional theory (DFT) with appropriate exchange-correlation functionals to beyond DFT methods under the framework of many body perturbation theory (viz., G0W0@HSE06). We have started with 32 primary set of combinations of metals M(I), M(II), M(III), and halogen X at Ag/In and Cl sites, respectively, where the concentration of each set is varied to build a database of nearly 140 combinations. The most suitable mixed sublattices are identified to engineer the bandgap of Cs2AgInCl6 to have its application in optoelectronic devices under visible light.
Aerodynamic performance of profiled endwalls with upstream slot purge flow in a linear turbine cascade having pressure side separation
Authors: Babu Sushanlal , Anish S.
Published: January 2021

In aeroengines, purge flow directly fed from the compressor (which bypasses the combustor) is introduced through the disk space between blade rows to prevent the hot ingress. Higher quantity of purge gas fed through the wheel space can provide additional thermal protection to the passage endwall and blade surfaces. However, the interaction of purge flow with the mainstream flow leads to higher secondary losses. Secondary losses inside a turbine blade passage can be reduced effectively by endwall contouring. This paper presents computational investigation on the influence of non-axisymmetric endwall contouring over endwall secondary flow modification in the presence of purge flow with the pressure side bubble (PSB). The experimental analysis was conducted for the base case without purge and base case with purge (BCP) configurations having flat endwalls. The total pressure loss coefficient and exit yaw angle deviation were measured with the help of a five-hole pressure probe. Static pressure distribution over the blade midspan was obtained by 16 channel Scanivalve. Aerodynamic performances of three different profiled endwalls are numerically analyzed and are compared against the BCP configuration. The effects of different contoured endwall geometries on endwall static pressure distribution and secondary kinetic energy were also discussed. Analysis shows that in the first contoured endwall configuration (EC1), the formation of stagnation zones at a contour valley close to the suction surface causes the exit total pressure loss coefficient to increase. The shifting of the contour valley near to the pressure surface (EC2 configuration) has resulted in local acceleration of the diverted pressure side leg of the horseshoe vortex over the hump toward the end of the passage. In the third configuration (EC3 configuration), reduced valley depth and optimum hump height have effectively redistributed the endwall pitchwise pressure gradient. The increased static pressure coefficient at the endwall near to the pressure surface has eliminated the PSB formation. In addition, computational results of unsteady Reynolds averaged Navier–Stokes simulations are obtained for analyzing transient behavior of PSB, with more emphasis on its migration on the pressure surface and transport across the blade passage. The additional work done by the mainstream fluid to transport the low momentum PSB fluid has caused higher aerodynamic penalty at the blade exit region. In this viewpoint, the implementation of contoured endwalls has shown beneficial effects by eliminating the PSB and related secondary vortices. At 27% of axial chord downstream of the blade trailing edge, a 4.1% reduction in the total pressure loss coefficient was achieved with endwall contouring.
Analysis of the improved thermal stability of Al-doped ZnO-adopted organic solar cells
Authors: Kim Jaehoon , Lee Yeonkyung , Kim Jun Young , Song Hyung-Jun , Song Jiyun , Lee Hyunho , Lee Changhee
Published: January 2021

The stable performance of organic solar cells (OSCs) at high temperatures is a critical issue for their commercialization. Although a few studies have reported the improved stability of OSCs that adopted Al-doped ZnO (AZO) as an electron transport layer (ETL), systematic research that validates the origins of this improvement has been lacking. In this work, we investigated the underlying mechanism for the improved stability of an OSC with AZO. By adopting AZO, the power conversion efficiency reached 8.65% and retained 70% of its initial value at 85 °C for 6 h, which was an increase in stability of 46% compared to that of an OSC with pristine ZnO. We found that the improved stability of the OSC with AZO originated from the decrease in oxygen defects and the space-charge limited current region through trap-related analyses and the Mott-Gurney law. Therefore, the results supported the enhanced thermal stability of OSCs that incorporated AZO as an ETL.
Polyvinyl acetate-based polymer host for optical and far-infrared spectroscopy of individualized nanoparticles
Authors: Wladkowski Henry V. , Duarte Julian , Nandyala Shashank R. , Walker Joshua S. , Kattel Subash , Blackburn Jeffrey L. , Fagan Jeffrey A. , Pikal Jon M. , Rice William D.
Published: January 2021

Preparation techniques for producing films of individualized solution-dispersed nanoparticles (NPs) for optical spectroscopy are often technically challenging and tailored for a specific NP system. In this work, we present a rapid, easy, and economical technique for producing polyvinyl acetate (PVAc)-based NP-polymer films on the order of 100’s of micrometers thick that exhibit high uniformity, low aggregation, excellent optical transparency, and low terahertz absorption. In addition, we find that these films are robust at cryogenic temperatures and have a high laser damage threshold of 0.3 TW cm−2, which make them suitable for pulsed laser measurements. We show that free-standing, flexible, PVAc films can incorporate both one-dimensional single-wall carbon nanotubes (SWCNTs) and zero-dimensional Au NPs. Using absorbance, Raman scattering, and photoluminescence excitation spectroscopy, we observe that SWCNT individualization is maintained, and minimized polymer strain imposed, when the nanotubes are transitioned from the solution to the polymer host. This PVAc-based polymer host presents researchers with a straightforward method for producing free-standing and flexible NP films with low aggregation.
Quantifying the destructuring of a thixotropic colloidal suspension using falling ball viscometry
Authors: Biswas Rajkumar , Saha Debasish , Bandyopadhyay Ranjini
Published: January 2021

The settling dynamics of falling spheres inside a Laponite suspension is studied. Laponite is a colloidal synthetic clay that shows physical aging in aqueous suspensions due to the spontaneous evolution of inter-particle electrostatic interactions. In our experiments, millimeter-sized steel balls are dropped in aqueous Laponite suspensions of different ages (i.e., time elapsed since sample preparation). The motion of the falling balls is captured using a high-speed camera, and the velocities of their centroids are estimated from the images. Interestingly, we observe that balls of larger diameters fail to achieve terminal velocity over the entire duration of the experiment. We propose a mathematical model that accounts for rapid structural changes (expected to be induced by the falling ball) in Laponite suspensions whose aging time scales are much slower than the time of fall of the ball. For a range of ball sizes and Laponite suspension ages, our model correctly predicts the time dependence of the ball velocity. Furthermore, fits to our model allow us to estimate the rates of destructuring of the thixotropic suspensions due to the passage of the falling ball.
Theoretical inspection of the spin-crossover [Fe(tzpy)2(NCS)2] complex on Au(100) surface
Authors: Palomino Carlos M. , Sánchez-de-Armas Rocío , Calzado Carmen J.
Published: January 2021

We explore the deposition of the spin-crossover [Fe(tzpy)2(NCS)2] complex on the Au(100) surface by means of density functional theory (DFT) based calculations. Two different routes have been employed: low-cost finite cluster-based calculations, where both the Fe complex and the surface are maintained fixed while the molecule approaches the surface; and periodic DFT plane-wave calculations, where the surface is represented by a four-layer slab and both the molecule and surface are relaxed. Our results show that the bridge adsorption site is preferred over the on-top and fourfold hollow ones for both spin states, although they are energetically close. The LS molecule is stabilized by the surface, and the HS–LS energy difference is enhanced by about 15%–25% once deposited. The different Fe ligand field for LS and HS molecules manifests on the composition and energy of the low-lying bands. Our simulated STM images indicate that it is possible to distinguish the spin state of the deposited molecules by tuning the bias voltage of the STM tip. Finally, it should be noted that the use of a reduced size cluster to simulate the Au(100) surface proves to be a low-cost and reliable strategy, providing results in good agreement with those resulting from state-of-the-art periodic calculations for this system.
Fully consistent Eulerian Monte Carlo fields method for solving probability density function transport equations in turbulence modeling
Authors: Wang Haifeng
Published: January 2021

The probability density function (PDF) transport equation method is a sophisticated model for the closure of turbulent mixing and turbulent reactive flows. An efficient solution approach for solving the PDF transport equation has been vital for the method to be widely used in applications. The Eulerian Monte Carlo fields (EMCF) method has been developed to solve the PDF transport equation efficiently for decades. A recent work by Wang et al. [Phys. Fluids 30, 115106 (2018)] revealed a serious issue of the EMCF method for not being fully consistent with the PDF transport equation for which the method is designed to solve. This work advances the state of the art by introducing fully consistent EMCF methods for solving the PDF transport equation. The fully consistent EMCF formulations are derived for two different PDF equation forms. The consistency of the EMCF formulations is mathematically confirmed by examining the derived moment transport equations from the EMCF formulations and from the PDF transport equation. The method of manufactured solutions is employed to further verify the consistency and convergence of the different EMCF formulations numerically. The newly introduced EMCF formulations bring the EMCF method to full consistency with the PDF transport equations for the first time.
Anomalous phonon softening of G-band in compressed graphitic carbon nitride due to strong electrostatic repulsion
Authors: Yang Zhenxing , Mahmood Javeed , Niu Shifeng , Tian Hui , Ji Tingting , Liu Cailong , Baek Jong-Beom , Sundqvist Bertil , Yao Mingguang , Liu Bingbing
Published: January 2021

Graphitic carbon nitride (C2N and C3N) with various π electron distributions on layers have been studied under pressure through a combined theoretical and experimental approach and a comparison with graphite. It is found that as these materials transform into low compressibility phases in the pressure range from 15 to 45 GPa, strong electrostatic repulsion between π electrons and in-plane sp2 electrons may distort and soften the sp2 bonds, leading to anomalous pressure evolutions of the intralayer phonon vibrations, such as a plateau-like behavior of E2g mode (G-band) in C2N and C3N. This also causes a slow increase in the resistivity/resistance of C2N and C3N as pressure increases, and the gradual interlayer bonding leads to an abrupt increase in resistance of the materials but with different pressure responses due to their different π electron distributions. Moreover, the intensity enhancement of the G band in both CN materials may be related to their electronic structure changes. The results deepen our understanding of the effects of π electron distribution on the structural transition of graphitic materials and may explain some unexplained in previous studies.
Dynamics of a rodlike deformable particle passing through a constriction
Authors: Han Yunlong , Li Rui , Ding Mingming , Ye Feng , Shi Tongfei
Published: January 2021

We use the finite element method to investigate the flow-induced translocation of a rodlike deformable particle through a narrow constriction in a microchannel from a dynamical perspective. Our results demonstrate that the deformable particle exhibits two translocation modes, one with folded deformation and one with unfolded deformation, depending mainly on the initial deflection angle. When the initial deflection angle is small, the deformable particle undergoes folded deformation, which changes to unfolded deformation as the angle increases. Depending on its initial location with respect to the axis of the microchannel, the deformable particle exhibits swinging motion or one of two types of tumbling motion: tumbling I (90° < θ < 180°, where θ is the rotation angle) and tumbling II (θ > 180°). Swinging motion occurs when the initial position is close to the axis, and this is converted to tumbling I and tumbling II motions when the initial position moves away from the axis. Our results provide a description of the deformation and motion of a rodlike deformable particle during its passage through a constriction, which can be useful for understanding the role of deformable particles in physiological processes, for cell separation, and for the application of deformable particles in drug delivery.
Droplet evaporation residue indicating SARS-COV-2 survivability on surfaces
Authors: He Zilong , Shao Siyao , Li Jiaqi , Kumar S. Santosh , Sokoloff J. B. , Hong Jiarong
Published: January 2021

We conducted a systematic investigation of droplet evaporation on different surfaces. We found that droplets formed even with distilled water do not disappear with evaporation but instead shrink to a residue of a few micrometers lasting over 24 h. The residue formation process differs across surfaces and humidity levels. Specifically, under 40% relative humidity, 80% of droplets form residues on plastic and uncoated and coated glass, while less than 20% form on stainless steel and none on copper. The formation of residues and their variability are explained by modeling the evaporation process considering the presence of nonvolatile solutes on substrates and substrate thermal conductivity. Such variability is consistent with the survivability of SARS-CoV-2 measured on these surfaces. We hypothesize that these long-lasting microscale residues can potentially insulate the virus against environmental changes, allowing them to survive and remain infectious for extended durations.
Viscoelastic flow instabilities in static mixers: Onset and effect on the
mixing efficiency
Authors: Migliozzi S. , Mazzei L. , Angeli P.
Published: January 2021

Elastic instabilities are identified as flow instabilities occurring in the presence of low inertial effects, induced by the combination of strong elastic forces with nonlinearities of the flow. In continuous flow laminar mixing applications, the onset of these instabilities is likely to occur in the window of applied flow rates; therefore, it is important to understand the effects of their onset on the process efficiency. In this work, we investigated experimentally the onset of elastic instabilities in two tubular static mixers with different geometric features, i.e., the Kenics helical mixer and the SMB-R mixer, the latter characterized by a double X-shaped bar geometry. We obtained concentration maps at various mixer lengths by means of planar laser induced fluorescence techniques. To deduce a generalized effect of the fluid elasticity on the mixing patterns, we tested three fluids with different rheological behavior—a Boger fluid and two shear-thinning fluids. For all cases, we observed deviations from the Newtonian benchmark as soon as the Deborah number exceeded unity, even though different transitions occurred as the mean flow rate increased. The effect of the instability on the mixing patterns strongly depended on the different kinematics induced by the two geometries: for the helical mixer, the typical lamellar structure is not recovered and the two liquid streams remain unmixed, while for the SMB-R, the concentration maps are strongly unsteady, showing temporally and spatially chaotic fluctuations of the mass fraction. In both cases, the instabilities worsen the mixing efficiency compared to the Newtonian case.
Origin of Hysteresis in Perovskite Solar Cells
Authors: Singh Ranbir , Parashar Mritunjaya
Published: January 2021

The presence of hysteresis in perovskite solar cells (PSCs) complicates the reliable evaluation of cell performance for practical applications. Numerous efforts have been made to figure out the reasons behind this phenomenon and to resolve the hysteresis, but it still needs to be explored for better understanding. This chapter is mainly focused on theoretical and experimental studies to reveal the origin of the hysteresis and discuss the remedies to eliminate the hysteric behavior in PSCs. In the last few years, the PSC has emerged as one of the fastest growing photovoltaic technologies that achieved high-power conversion efficiency (>25%) in a short span of time. Despite the high efficiency attained, PSCs suffer from current density-voltage (J-V) hysteresis when J-V characteristics were traced in forward and reverse scans. The presence of hysteresis in PSCs significantly influences the photovoltaic (PV) properties and most importantly device stability. Generally, the hysteric behavior in a PSC arises due to ferroelectric polarization, charge carrier trapping/detrapping, and ion migration in the perovskite materials. A systematic discussion on the key factors involved in the hysteresis generation and how it can be eliminated from PSCs, which includes improvement in morphology by either increasing grain sizes, additive doping, interface engineering, device architecture, etc. On the other hand, the hysteresis can also be positively utilized in other applications such as memristive switching devices.
Homological dimensions of Banach spaces
Authors: Sánchez F. Cabello , Castillo J. M. F. , García R.
Published: January 2021

The purpose of this paper is to lay the foundations for the study of the problem of when

in Banach spaces. We provide a number of examples of couples

,

such that

is (or is not)

. We show that

for all

when

is the Kadec space. In particular, both the projective and injective dimensions of

are infinite.

Bibliography: 48 titles.
Identification of existing pharmaceuticals and herbal medicines as inhibitors of SARS-CoV-2 infection
Authors: Jan Jia-Tsrong , Cheng Ting-Jen Rachel , Juang Yu-Pu , Ma Hsiu-Hua , Wu Ying-Ta , Yang Wen-Bin , Cheng Cheng-Wei , Chen Xiaorui , Chou Ting-Hung , Shie Jiun-Jie , Cheng Wei-Chieh , Chein Rong-Jie , Mao Shi-Shan , Liang Pi-Hui , Ma Che , Hung Shang-Cheng , Wong Chi-Huey
Published: January 2021

Significance

COVID-19 is a global pandemic currently lacking an effective cure. We used a cell-based infection assay to screen more than 3,000 agents used in humans and animals and identified 15 with antiinfective activity, ranging from 0.1 nM to 50 μM. We then used in vitro enzymatic assays combined with computer modeling to confirm the activity of those against the viral protease and RNA polymerase. In addition, several herbal medicines were found active in the cell-based infection assay. To further evaluate the efficacy of these promising compounds in animal models, we developed a challenge assay with hamsters and found that mefloquine, nelfinavir, and extracts of
Ganoderma lucidum
(RF3),
Perilla frutescens
, and
Mentha haplocalyx
were effective against SARS-CoV-2 infection.
Cross-linguistic influence in the second language processing of Korean morphological and syntactic causative
constructions
Authors: Park Sun Hee , Kim Hyunwoo
Published: January 2021

This study investigated the effects of cross-linguistic influence in Japanese speakers’ integration of
morphological and syntactic information during the processing of Korean transitive causative constructions. We examined whether
Japanese speakers would process two types of Korean causative constructions as efficiently as native speakers: (a) when one target
structure was instantiated differently from learners’ L1 correspondents and (b) when the other type was unique to the L2. Although
the learners showed native-like performance during an acceptability judgment task, they had difficulties with the integration of
morphological and syntactic information during a self-paced reading task when the target construction gave rise to
cross-linguistic competitions with the L1 correspondent, but not when the target construction was unique to the L1. Our findings
support the claim that cross-linguistic cue competitions are a major source of difficulties in L2 sentence processing.
Corrigendum: Analytic expressions for gravitational inner multipole moments of elementary solids and for the force between two rectangular solids (2005 Class. Quantum Grav.
23
125)
Authors: Lee J G , Adelberger E G , Collins N A , Hoyle C D
Published: January 2021

We correct errors in seven of the more than 100 expressions for the gravitational inner spherical multipole moments of several homogeneous solids. No additional corrections have been found.
A high-precision unmanned aerial vehicle positioning system based on ultra-wideband technology
Authors: Li Tian-yu , Duan Fa-jie , Liang Chun-jiang , Jiang Jia-jia , Fu Xiao , Wang Qi , Huang Hui-xiong , Wei Qi-feng
Published: January 2021

With the help of artificial intelligence technology, the unmanned aerial vehicle (UAV) industry is booming. In the civilian field, a series of fully functional UAV products have emerged one after another, giving birth to a huge industrial chain. To strengthen the UAV market supervision, many countries have introduced a series of standards to regulate UAV products, but they have not yet developed a high-precision positioning system for UAV quality inspection. In this paper, we proposed a high-precision UAV positioning method based on ultra-wideband (UWB) technology. We analyzed the algorithm, base station layout, and clock synchronization to improve the accuracy of the UWB positioning system and established a high-precision UAV trajectory tracking and measurement system based on UWB technology, realizing real-time high-precision positioning of UAVs. Based on the Chan algorithm, we analyzed the base station layout method in combination with the system construction site and proposed a new delay calibration method between positioning base stations. Experimental results show that we have achieved a horizontal accuracy of under 0.1 m and a vertical accuracy of under 0.15 m in a space of 120 m × 60 m × 40 m.
Magnetohydrodynamic simulations of runaway electron beam termination in JET
Authors: Bandaru V , Hoelzl M , Reux C , Ficker O , Silburn S , Lehnen M , Eidietis N , Team JOREK
Published: January 2021

A runaway electron (RE) fluid model is used to perform non-linear magnetohydrodynamic simulations of a relativistic electron beam termination event in JET. The case considered is that of a post-disruption low density cold plasma in the runaway plateau phase, wherein high-Z impurities have been largely flushed out via deuterium second injection (Shot:95135). Details of the experiment are found in separate publications. Our studies reveal that a combination of low plasma density and a hollow current profile which is confirmed by experimental studies causes fast growth of a double-tearing mode, which in turn leads to stochastization of the magnetic field and a prompt loss of REs. The phenomenology of events leading to the crash and the timescales of the dynamics are in excellent agreement with the experiment. Simulations also indicate significant toroidal variation in RE deposition but without localized hotspots. The strong stochastization setting in first from the edge leads to a poloidally broad deposition footprint that partly explains the benign nature of the termination event. This work further supports the potential possibility to engineer a benign RE beam termination scenario via deuterium second injection in ITER, as proposed by Reux et al ‘Runaway electron beam suppression using impurity flushing and large magnetohydrodynamic instabilities’ (submitted to Physical Review Letters).
Manipulating electronic dynamics of 8-Pmmn borophene with surface optical phonons
Authors: Akay Defne
Published: January 2021

In this work, the effects of surface optical (SO) phonons on the electronic spectrum of 8-Pmmn phase borophene have been investigated. To describe the analytical model we used a Fröhlich-type Hamiltonian on a borophene system within the continuum limit. Then, by following the analytical model with the Lee–Low–Pines variational approximation method, including two successive unitary transformations, the system Hamiltonian has been diagonalized. Our theoretical analysis indicates that SO absorption of the system strongly depends on the substrate-induced effects of the system. Moreover, it is observed that the polaronic energy gap decreases when increasing the internal distance

z

between the 8-Pmmn borophene and the particular substrate. Also, the energy gap increases with increasing phonon energy (

ℏ
ω

). In addition, the resulting bandgap induced by the electron–SO phonon interaction can be tuned by the associated interaction strengths of the substrate. Furthermore, taking lattice vibrations into account, the surface phonon specific heat of the system has been evaluated as a function of temperature. The specific heat becomes constant at high temperatures, as in the Einstein model. We specifically evaluated the contribution from the lattice vibrations on specific internal distances, z. The increase in the internal distance z causes the peak to shift to lower thermal energy.
A novel traveling wave piezoelectric actuated wheeled robot: design, theoretical analysis, and experimental investigation
Authors: Jia Botao , Wang Liang , Wang Ruifeng , Jin Jiamei , Zhao Zhenhua , Wu Dawei
Published: January 2021

Traditional traveling wave robots have strict requirements on the operating interface due to the fact that they usually only work on smooth and flat surfaces, holding the disadvantages of poor load capacity and complex driving mode, and limiting their application range. In order to overcome the above problems, a novel traveling wave piezoelectric actuated wheeled robot is proposed in this study. The robot is composed of a bonded-type piezoelectric actuator and wheel mechanisms. Rotating traveling wave can be produced in the annular parts of the piezoelectric actuator to drive the wheel mechanisms. In order to study the dynamic characteristics of the piezoelectric actuator, an electromechanical coupling model is developed by using the transfer matrix method. Then the prototype of the piezoelectric actuator is fabricated and assembled, and its vibration characteristics are measured to confirm the feasibility of the developed transfer matrix model. Finally, performance evaluation investigations of the proposed traveling wave piezoelectric actuated wheeled robot are conducted. Under the excitation voltages of 350 V
pp and the phase difference of 90°, the robot prototype achieved a step climbing angle of 75°, a maximum no-load velocity of 136.8 mm s−1, and a maximum payload of 320 g. The proposed traveling wave piezoelectric actuated wheeled robot presents expected terrain adaptability and obstacle climbing capability.
Modulation instability, rogue waves and conservation laws in higher-order nonlinear Schrödinger equation
Authors: Dong Min-Jie , Tian Li-Xin
Published: January 2021

In this paper, the modulation instability (MI), rogue waves (RWs) and conservation laws of the coupled higher-order nonlinear Schrödinger equation are investigated. According to MI and the 2 × 2 Lax pair, Darboux-dressing transformation with an asymptotic expansion method, the existence and properties of the one-, second-, and third-order RWs for the higher-order nonlinear Schrödinger equation are constructed. In addition, the main characteristics of these solutions are discussed through some graphics, which are draw widespread attention in a variety of complex systems such as optics, Bose–Einstein condensates, capillary flow, superfluidity, fluid dynamics, and finance. In addition, infinitely-many conservation laws are established.
SiGoba - Learning Media Based on Android Applications for Introducing Medicine’s Classes and Functions
Authors: Mustafidah H , Prihardianto O , Fatimah V A N , Fitri A S , Fitriana Y A N , Suwarsito S
Published: January 2021

In this covid-19 era pandemic, people are required to use computer technology to run the wheel of life, including learning something. Internet users, including smartphone users in Indonesia, are more than half of the population. Meanwhile, the body must be protected so that the body’s immunity is not susceptible to disease. If you are already sick, you must immediately be treated with the right medicine. If the use of drugs is not proper, surely the pain will get worse. But there are still many people who do not understand the class and function of drugs as they should. Therefore, this research develops an android-based application called SiGoba, an information system as a learning medium to recognize the class and function of drugs according to the Indonesian Drug Specialist Information (ISO). Drug data used are drugs commonly consumed by Indonesian people to treat minor ailments. This system was built using the waterfall model, with black-box testing. The system test results show that SiGoba has a function as a learning medium for recognizing drug classes and functions. We hope that SiGoba can be a learning media for the community so they can learn about how to use drugs according to their groups and functions, so it does not cause medication wrong. If this happens, it will have an impact on the recovery of the illness.
Mitigating the impact of bad rainy seasons in poor agricultural regions to tackle deforestation
Authors: Leblois Antoine
Published: January 2021

Land use changes are known to account for over 20% of human greenhouse gas emissions and tree cover losses can significantly influence land-climate dynamics. Land-climate feedbacks have been identified and evaluated for a long time. However, in addition to the direct effect of climate change on forest biomes, recent sparse evidence has shown that land use changes may increase as a result of weather shocks. In Western and Central Africa, agriculture is the main source of income and employment for rural populations. Economies rely on agricultural production, which is largely rainfed, and therefore dependent predominantly upon seasonal rainfall. In this article, I explore the impact of seasonal rainfall quality on deforestation, by combining high-resolution remotely-sensed annual tree cover loss, land cover, human activity and daily rainfall data. I show that in poor regions that are mainly reliant on rainfed agriculture, a bad rainy season leads to large deforestation shocks. These shocks notably depend on the proportion of agricultural land and on the remoteness of the areas in question, as remoteness determines the ability to import food and the existence of alternative income sources. In areas with significant forest cover, a short rainfall season leads to a 15% increase in deforestation. In unconnected areas with small proportions of crop area, the increase in deforestation reaches 20%. Findings suggest that a refined understanding of the land use changes caused by rainfall shocks might be used to improve the design and effectiveness of development, adaptation and conservation policies.
“Smart” city” concept for settlements in the Arctic zone of the Russian Federation
Authors: Didenko N I , Skripnuk D F , Kulik S V , Kosinski Eryk
Published: January 2021

The paper deals with issues related to the use of the concept of a “smart” city. It is concluded that the “smart” city concept is reviewed in the scientific literature and has practical achievements for large cities. The analysis of features of the Arctic zone of the Russian Federation in the context of innovative development is carried out. The analysis of the process of population distribution in the Arctic zone of the Russian Federation and its result - a network of settlements - is presented. The conclusion is made that the Arctic zone should be the place where, first of all, it is necessary to test the “smart” city concept, and the existing network of settlements and interrelation of various types of settlements in the Arctic zone should be used as the objects of using the technologies of the “smart” city concept and their applications. The technologies of the “smart” city concept, which can be used for different types of settlements in the Arctic zone, are determined. The methodological approach taken as the basis for this paper includes: a) an analytical review of literature, focused on the geographical, technological, and institutional characteristics and abilities to implement the concept of sustainable development of the AZRF on the basis of using information and communication technologies (ICT), robotics, and intelligent solutions in the projects of the “smart” city; b) conceptual construction of the real-world virtual cyberspace of the AZRF, or a complex of “socio-cyber-physical systems and intellectual space”, which could serve not only for the purposes of monitoring of the mentioned area but in the future could also become a flexible and multi-faceted tool for managing sustainable development of the AZRF. Keywords: Arctic zone of the Russian Federation, development drivers, real-virtual cyberspace, sustainable development, unmanned aerial vehicles.
BIORHYTHMOLOGICAL PORTRAIT OF WORKERS OF THE DRILLING CREW IN EXTREME NORTHERN LATITUDES
Authors: Anastasia Bashkireva , Tatiana Bashkireva , Nadezhda Fateeva , Alexander Severin
Published: January 2021

Each organism at an individual level builds its system of temporary relationships with the different amplitude of oscillations - an individual biorhythmological portrait. Using Holter monitoring in the AnnaFlash2000 software in the ISCIM6 statistical processing, the ultradian rhythms of the driller crew in extreme northern latitudes studied. It revealed that the individual rhythmic processes of acrophase and cardiac rhythm bathyphase, which testify to the leading role of hypoxia, hypercapnia in adaptive mechanisms, influence the joint professional activity of small labour groups. It established that working in different biological rhythms, the driller’s team has a low degree of compatibility. The synchronization of biological rhythms in the team is achieving by the general properties of temperament as phlegmatic. More successful in adaptation - phlegmatic sanguine.
How do Southeast Asian countries participate in the development of the Arctic
Authors: Krasnozhenova E E , Kulik S V , Chistalyova T , Yu Eidemiller K , Karabushenko P L
Published: January 2021

The Arctic has been of particular importance for a lot of countries, but circumpolar states, including Southeast Asia states, for many years. For Southeast Asia state it is very useful to take part in the Arctic development because they get the opportunity to sell their technologies and use their research results. The feature of Southeast Asia states policy is the intention to sell their equipment and to help to provide the region with the appropriate infrastructure. Thus, the economic interests are of the great importance in the cooperation with circumpolar states. For circumpolar states this cooperation is also very important because they may extend their opportunities in the region due to acquiring of the essential technologies.
The Arctic policy of the Republic of Korea
Authors: Krasnozhenova E E , Kulik S V , Chistalyova T , Yu Eidemiller K , Karabushenko P L
Published: January 2021

Nowadays the Arctic attracts a lot of countries all over the world, including Asian ones, due to its features, especially its abundant resources and research potential. In the paper the authors consider the Arctic policy of the Republic of Korea. Shipping and sea trade, oil and gas prospection, scientific research are of particular importance for South Korea. International cooperation with the circumpolar states and protection of indigenous people and nature preservation are also essential for the country. To achieve these goals the government of the state has designed several policy documents which provide the authors with the information for this research.
MILITARY-GEOGRAPHICAL DESCRIPTIONS OF THE ARCTIC AND SUBARCTIC TERRITORIES OF THE RUSSIAN NORTH DURING THE CIVIL WAR AND IN THE 1920-30s
Authors: Mikhailov A A , Abakumova V , Aladishkin I V
Published: January 2021

The article considers the activities of the military bodies of Soviet Russia (USSR) in the military-geographical study of the Arctic and Arctic territories of the Russian North during the Civil War and a decade afterwards. It analyzes some particular descriptions and reviews of the region, as well as reveals the view of military professionals on the natural environment characteristics and economy of the northern territories.
Features of the population settlement system in the regions of the China – Mongolia – Russia economic corridor
Authors: Osodoev P V , Zhamyanova Y B
Published: January 2021

The article presents an analysis of the existing objective conditions and patterns of population distribution on the territory of the China – Mongolia – Russia economic corridor. The study area covers the Inner Mongolia Autonomous Region of China (Inner Mongolia), the central aimags of Mongolia and the Baikal region (Russia). The settlement system of adjacent regions is highly differentiated in terms of natural and geographical conditions, the level of production development, socioeconomic development, and the state of infrastructure. The average population density of the study area is 10.1 people per km2: there are relatively low indicators in the Baikal region, 2.8 people per km2; 4.2 people per km2 are in the central regions of Mongolia, and 21.2 people per km2 are in Inner Mongolia. The highest population density is observed in areas where highways and railways pass. During the period under review (from 2000 to 2018), the indices of population change in adjacent regions amounted to 93.7% in Russia, 129.0% in Mongolia and 106.7% in China. In the study regions, the population lives mainly in cities and large settlements. In the Baikal region, the level of urbanization is 68.6%, in Mongolia – 67.8% and in Inner Mongolia – 62.7%. The growth of cities is mainly due to internal migration, especially in the Russian and Mongolian territories; the process of depopulation of the countryside is taking place.
Transient process modeling in micrologistic transport systems
Authors: Zharkov M L , Kazakov A L , Lempert A A
Published: January 2021

Micrologistic transport systems are ports, transport hubs, railway terminals (railway stations and marshalling yards), and other micro-level transport objects. Such systems are dynamic ones, whose parameters are time-dependent. Consequently, transient processes appear. These processes last for some time and then subside. Then the system goes into a stationary mode of operation. To solve most engineering problems, it is sufficient to find the stationary characteristics of the system. However, some problems require knowledge of the properties of transients. In this paper, we use the previously presented technology for modeling the operation of micrologistic transport systems to study transients in various transport objects. We consider two types of micrologistic transport systems, such as passenger and cargo, and design their models in the form of two-phase and three-phase queuing systems with BMAP flows. For these queuing systems, we compile Kolmogorov systems of ordinary differential equations. Their analytical study is difficult; therefore, to solve such systems, we use numerical methods. Overall, we find the transition probabilities of system states. We compare the obtained probabilities with stationary characteristics, which allows us to draw conclusions about the properties of transients in the considered systems.