Normal Field Research Articles

Solar Wind Current Sheets: MVA Inaccuracy and Recommended Single‐Spacecraft Methodology

AbstractWe present the analysis of 1,831 current sheets (CS) observed aboard four Cluster spacecraft in a pristine solar wind. Four‐spacecraft estimates of the CS normal and propagation velocity are compared with different single‐spacecraft estimates. The Minimum Variance Analysis (MVA) of the magnetic field is shown to be highly inaccurate in estimating the normal. The MVA normal often differs by more than 60° from the normal obtained by multi‐spacecraft timing method, likely due to ambient turbulent fluctuations. In contrast, the cross‐product of magnetic fields at the CS boundaries delivers the normal with an uncertainty of less than 15° at the confidence level of 90%. The CSs are essentially frozen into plasma flow, since their propagation velocity is consistent with local ion flow velocity within 20% at the confidence level of 90%. The single‐spacecraft methodology based on the cross‐product method and frozen‐in assumption delivers the CS thickness and current density amplitude within 20% of their actual values at the confidence level of 90%. The CSs are kinetic‐scale structures with half‐thickness λ from a few tenths to tens of local proton inertial length λp and scale‐dependent shear angle and current density amplitude, and . The classification of the CSs in terms of tangential and rotational discontinuities remains a challenge, because even the four‐spacecraft normal has too large uncertainties to reveal the actual normal magnetic field component. The presented results will be valuable for the analysis of solar wind CSs, when only single‐spacecraft measurements are available.

Investigation of thermomagnetic convective flow in vertical layers between water and kerosene based magnetic fluids

In this article, the convective flow in a vertical layer subjected to a consistent magnetic field with nonzero gravity condition is investigated. One side of the vertical walls is heated, while the opposite side is cooling. The magnetic field strength, field orientation angle, magnetization effect, and thermal deviation of vertical walls play important roles as controlling parameters on the flow stabilization. The goal of this investigation is to analyze the flow characteristics and find out the significant distinction between water and kerosene based magnetic fluids under the variation of thermal and magnetic effects. The numerical results are obtained by the pseudo-spectral Chebyshev expansion method. The properties of all instability modes caused by three major mechanisms, namely; thermomagnetic, thermogravitational and magneto-gravitational are analyzed. In the normal magnetic field, the wave speed responds faster, and it is recognized by a relatively small wave number in water based fluid than that in kerosene based fluid. In oblique magnetic field, the waves propagate faster in both kerosene and water based fluids with the field inclination angle increases, but they still propagate slower in kerosene based fluid comparatively in water based fluid. According to the linear or non-linear magnetization law, both upward and downward propagating waves in kerosene based fluid propagate slower, and they are recognized by greater wave numbers than that in water based fluid. It is found that the basic flow in water based fluid is much more stable than in kerosene based fluid.

Codimension two spacelike submanifolds in Lorentzian manifolds and conformal structures

Starting from a Riemannian conformal structure on a manifold M, we provide a method to construct a family of Lorentzian manifolds. The construction relies on the choice of a metric in the conformal class and a smooth 1-parameter family of self-adjoint tensor fields. Then, every metric in the conformal class corresponds to the induced metric on M seen as a codimension two spacelike submanifold into these Lorentzian manifolds. Under suitable choices of the 1-parameter family of tensor fields, there exists a lightlike normal vector field along such spacelike submanifolds whose Weingarten endomorphism provide a Möbius structure on the Riemannian conformal structure. Conversely, every Möbius structure on a Riemannian conformal structure arises in this way. Flat Möbius structures are characterized in terms of the extrinsic geometry of the corresponding spacelike surfaces.

Active and passive controls of magnetized Buongiorno Reiner–Phillipoff nanofluid

This attempt demonstrates the nature of mass and heat transportation in non-Newtonian Reiner–Philippoff liquid flow over moving surface by considering zero and nonzero normal mass flux conditions and transverse magnetic field. Thermophoresis and Brownian movement is accounted due to the Buongiorno model of nanofluid. The expressions of flow are reframed through appropriate variables into pairs of self-similar expressions. Further, these self-similar expressions are executed numerically through the Shooting procedure (Runge–Kutta 4th order). Numerical benchmarks and graphical illustrations are prepared to visualize the role of influential constraints on interesting quantities. It is observed that Lorentz force is beneficial in obtaining effective velocity and heat transfer. Improvement in thermophoresis factor enriches temperature field in case of active control while reverse nature is observed in passive control situation.

Relationship of Magnetic Domain and Permeability for Clustered Soft Magnetic Narrow Strips with In-Plane Inclined Magnetization Easy Axis on Distributed Magnetic Field.

A unique functionality was reported for a thin-film soft magnetic strip with a certain angle of inclined magnetic anisotropy. It can switch magnetic domain by applying a surface normal field with a certain distribution on the element. The domain switches between a single domain and a multi-domain. Our previous study shows that this phenomenon appears even in the case of the adjacent configuration of multiple narrow strips. It was also reported that the magnetic permeability for the alternating current (AC) magnetic field changes drastically in the frequency range from 10 kHz to 10 MHz as a function of the strength of the distributed magnetic field. In this paper, the correspondence of AC permeability and the magnetic domain as a function of the intensity of the distributed field is investigated. It was confirmed that the extension of the area of the Landau-Lifshitz-like multi-domain on the clustered narrow strips was observed as a function of the intensity of the distributed magnetic field, and this domain extension was matched with the permeability variation. The result leads to the application of this phenomenon to a tunable inductor, electromagnetic shielding, or a sensor for detecting and memorizing the existence of a distributed magnetic field generated by a magnetic nanoparticle in the vicinity of the sensor.

A bulk-surface continuum theory for fluid flows and phase segregation with finite surface thickness

In this continuum theory, we propose a mathematical framework to study the mechanical interplay of bulk-surface materials undergoing deformation and phase segregation. To this end, we devise a principle of virtual powers with a bulk-surface dynamics, which is postulated on a material body P where the boundary ∂P may lose smoothness, that is, the normal field may be discontinuous on an edge ∂2P. The final set of equations somewhat resemble the Navier–Stokes–Cahn–Hilliard equation for the bulk and the surface. Aside from the systematical treatment based on a specialized version of the virtual power principle and free-energy imbalances for bulk-surface theories, we consider two additional ingredients: an explicit dependency of the apparent surface density on the surface thickness and mixed boundary conditions for the velocity, chemical potential, and microstructure.

A normal line congruence and minimal ruled Lagrangian submanifolds in [formula omitted

We characterize Lagrangian submanifolds in complex projective space for which each parallel submanifold along normal geodesics with respect to a unit normal vector field is Lagrangian, by using a normal line congruence of the Lagrangian submanifold to complex 2-plane Grassmannian and quaternionic Kähler structure. As a special case, we can construct minimal ruled Lagrangian submanifolds in complex projective space from an austere hypersurface in sphere with non-vanishing Gauss-Kronecker curvature.

Supervision and early warning of abnormal data in Internet of Things based on unsupervised attention learning

With the continuous development of artificial intelligence and big data, more and more communication protocols have appeared in the network connection. Because the network protocol content specification should not need to obtain the content of the common protocol by any means, it faces different attacks, which increases the complexity of network security detection to an unlimited extent. The absolute security analysis of the content of the relevant data protocol is not too limited. Based on the content of the unknown binary number protocol in the Internet of Things, this paper does the reverse research. To address the inefficiency, learning is focused on the inverse aspect of the content processing logic of the protocol for unsupervised execution attention. This paper proposes a method based on the name of the Dirichlet process mixture model normal field and the unknown protocol of the Internet of Things. It also establishes the behavioral criteria that process the logical inference least squares method to infer the content of the target protocol. Based on the original external characteristics of abnormal data in the Internet of Things, the neural network model of attention mechanism and the model checking of variational self-encoder are chosen. An innovative multi-dimensional spatial neural network model with a centralized control mechanism is taken to extract the spatial relevant information from the original external features, which are regarded as the intermediate external features. The intermediate extrinsic features are input to a variational self-encoder for computation and reconstruction. The experimental results verify that the time required by the proposed model is 45% less than that of the traditional structure. The flow processing improves by 36.7% compared with the optimization of the parameter control function. The specific method only relies on the original external characteristics of the Internet of Things traffic and can achieve better data anomaly detection and classification under the condition of not significantly improving the detection time. The abnormal data detection scheme of the Internet of Things designed in this paper not only fills the detection gap of the current mainstream Internet of Things system which lacks an autonomous supervision mechanism, but also effectively blocks external network intrusion and further improves the management authority verification system. It plays an indispensable role in the long-term stable operation of the Internet of Things platform.

Distal Nasal Part of the Visual Field and RNFL in Primary Open-Angle Glaucoma.

The aim of this study was to compare changes in the conventionally undiagnosed distal nasal visual field with RNFL in patients with early primary open-angle glaucoma (POAG). 59 eyes of 32 patients (18 women, 14 men) with early stage POAG were included. All eyes were found to have a normal visual field (fast threshold program of 50 degrees nasally and 22 degrees temporally) with the Medmont M700. Visual acuity was 1.0 (with a possible correction ±3 D), and they had no other ocular pathology except glaucoma. The visual field was subsequently examined with the same instrument by moving the fixation point 40 degrees temporally (spatially adaptive program) and simultaneously turning the head 10 degrees nasally. A total of 89 examination points were included using flicker stimuli in a range of 0-120 degrees nasally. Nerve fiber layer (RNFL) and vessel density (VD) was measured using the in-built software of the Avanti RTVue XR instrument. Using Pearson's correlation coefficient, the results of visual field examination with RNFL without and after correction (by subtracting VD from total RNFL value) in the superior-nasal (SN-5) and inferior-nasal (IN-8) segments were compared. In all eyes, changes were found in the distal periphery of the nasal part of the visual field. No correlation was noted by comparison with RNFL. After adjusting RNFL for VD, we observed no correlation in the SN segment (5) (r=-0.03) and a very weak correlation in the IN segment (8) (r=-0.16). With a normal visual field tested by the rapid threshold glaucoma program, changes in the distal part of the nasal periphery of the visual field were found in the entire cohort and did not correlate with the RNFL and RNFL results after correction from VD.

Оснащенное гиперполосное распределение аффинного пространства

A rigged hyperstrip distribution is a special class of hyperstrips. The study of hyperstrips and their generalizations in spaces with various fun­damental groups is of great interest due to numerous applications in mathematics and physics. A special place is occupied by regular hyper­strips, for which the characteristic planes of families of principal tangent hyperplanes do not contain directions tangent to the base surface of the hyperstrip. In this work, we use E. Cartan’s method of external differen­tial forms and the group-theoretic method of G. F. Laptev. In affine space, a hyperstrip distribution is considered, which at each point of the base surface is equipped with a tangent plane and a conjugate tangent line. The specification of the studied hyperstrip distribution in an affine space with respect to a 1st order reference and an existence theorem are given. The fields of affine normals of the 1st kind for Blaschke and Transon are constructed and the conditions for their coincidence are found. The definition of normal affine connection and normal centroaffine connection on the studied framed hyperstrip distribution is given.

Determination of parameters of a homogeneous level ellipsoid by measured gravity values

The article considers the determination of the fundamentally non-measurable parameters of the mass (fm), small (b) and large (a) semi-axes of the normal gravitational field of a homogeneous level ellipsoid by the measured values of its angular velocity (ω), gravity at the equator (Ge) and pole (Gp), and also analytical formulas for determination.

Machine-learning to predict anharmonic frequencies: a study of models and transferability.

With more and more accurate electronic structure methods at hand, the inclusion of anharmonic effects in the post-processing of such data towards thermochemical properties is the next step. In this context, the description of anharmonicity has been an important topic of physical chemistry and chemical physics for a long time. In this study, anharmonic frequencies of various hydrogen-halides and halogenated hydrocarbon molecular clusters are calculated using harmonic as well as explicitly anharmonic methods, i.e., normal mode analysis and vibrational self-consistent field. Simple harmonic model based descriptors were used to predict anharmonic frequencies via multilinear regression and gradient boosting regression. Gradient boosting regression is capable of predicting reliable anharmonic data and even the simple multilinear regression model yields reasonable predictions that can account for mode-to-mode couplings. Moreover, the transferability to unseen chemical systems is assessed and it is confirmed that the machine-learned models can be applied to larger, unseen molecules.

Ligand field theory, Pauli shields and ultra-covalency in organometallic chemistry.

This paper explores the ligand field picture applied to organometallic compounds. Given the dearth of experimental data, the high-level ab initio ligand field theory (aiLFT) method is deployed as a surrogate for experiment and the necessary d orbital sequences and relative energies are obtained computationally. These are fitted to local cellular ligand field (CLF) σ, π and δ bonding parameters. Results are reported for planar [Cu(CR3)4]-, (R = F, H), octahedral M(CO)6n (M = Fe, Mn, Cr, V, Ti; n = +2, +1, 0, -1, -2), and the sandwich compounds M(Cp)2 (Cp = cyclopentadienyl, M = Fe, Ni, V), [Ni(Cp)2]2+ and Cr(C6H6)2. With respect to the aiLFT framework, these organometallic systems behave just like coordination complexes and most maintain the integrity of their formal dn configurations. Both [Cu(CR3)4]- compounds are formulated as low-spin d8 CuIII species and have normal ligand fields consistent with their planar geometries. The metal carbonyls reveal a new way of counting valence electrons which only requires the CLF d orbital energy level diagram to rationalise the 18-electron rule as well as its many exceptions. The bonding in sandwich compounds shows a remarkable variation. In ferrocene, Cp- behaves as a strong field ligand, comparable to [CN]- in [Fe(CN)6]4-. Fe(Cp)2 is low spin as is Cr(C6H6)2. Cp- in Fe(Cp)2 is a weak σ donor, strong π donor and weak δ acceptor while benzene in Cr(C6H6)2 is also a weak σ and strong π donor but is a much better δ acceptor. In contrast, Cp- is weak field in high spin, 20-electron Ni(Cp)2 but 'ultra-covalent' in [Ni(Cp)2]2+. The formal IV oxidation state is too high for the ligand set and the integrity of the d6 configuration is lost. Similarly, [V(CO)6]- and [Ti(CO)6]2- are ultra-covalent except now the formal metal oxidation states are too negative. Both mechanisms relate to the breaching of the metal's 3s23p6 'Pauli shield' and these ultra-covalent systems lie outside the ab initio ligand field regime. However, within the ligand field regime, the bonding in 'coordination complexes' and 'organometallic compounds' has the same conceptual footing and the nature of the local σ, π and δ interactions can be extracted from analysing the ligand field d orbitals.

Effect of Desorbed Gas on Dielectric Surface Discharge in Tangential and Normal Microwave Electric Fields in Vacuum

Effect of Desorbed Gas on Dielectric Surface Discharge in Tangential and Normal Microwave Electric Fields in Vacuum

Construction of new Lie group and its geometric properties

<abstract><p>In this paper, we constructed a novel Lie group by using oblate spheroidal coordinates. First, we took the metric tensor of oblate spheroidal coordinates, then found its Killing vectors by using the Killing equation. After solving a system of partial differential equations, we obtained the Killing vectors. With the help of these Killing vectors, we first constructed finite Lie algebra and then proved that Killing vectors form a Lie group. Also, we described the geometric properties in which this Lie group forms a regular surface, defined the differential map and differential of normal vector field, and found the gaussian and mean curvatures.</p></abstract>

NFL: Normal Field Learning for 6-DoF Grasping of Transparent Objects

NFL: Normal Field Learning for 6-DoF Grasping of Transparent Objects

Selection of heat tolerant donor lines in indian mustard (Brassica Juncea L.)

Heat stress during the post anthesis (seed filling) stage negatively influences the movement of photosynthates to the developing sinks and, thus lowering the seed yield in Indian mustard [Brassica juncea (L.) Czern & Coss]. The present studywas conducted with the objective to unravel the variability for terminal heat stress (THS) in a fixed diversitygenetic stock of 500 lines of Indian mustard. Germplasm stock exhibited huge variability for seed yield and its contributing traits with variable levels of yield reduction under late sown conditions. The per se yield based computed heat stress susceptibility index (HSI) ranged from 32.3 (highly THS susceptible) to -1.15 (THS tolerant). Based on yield reduction due to THS, 500 test genotypes were grouped into 10 classes and genotypes from each class wererandomly takento constitute a diverse panel of 96 lines. This panel was evaluated under THS by raising crop underpoly-tunnels during reproductive phase along with same set of 96 genotypes raised under normal field conditions (served as control). Based on agronomic advantage and HSI for economic traits, 23 heat tolerant donor lines were selected for utilization in commercial breeding programme. Bangladesh J. Bot. 52(4): 1007-1013, 2023 (December)

Gravity data reduction, Bouguer anomaly, and gravity disturbance

Each point on the earth has a gravity and gravity potential value. Surfaces formed by connecting points with equal gravity potential values are called equipotential surfaces or level surfaces. Determination of gravity field of the earth and the geoid which is one of the earth’s equipotential surfaces is very important for physical geodesy. Gravity values measured on the physical earth are not directly included in studies; firstly, they must be converted into gravity anomalies. For this, in this study precise leveling, gravity and GPS measurements were made in the field. Heights (H) with precise leveling measurements, gravity values (g) with gravity measurements and geographical latitudes (j) with GPS measurements were recorded. Then, gravity reductions (free-air, Bouguer) were calculated at the points. The actual gravity g measured on Earth is not immediately directly comparable to the normal gravity of the ellipsoid surface. Gravity values must be reduced to the geoid. Since there are masses outside the geoid, reduction methods differ according to the way these topographic masses are handled. Bouguer gravity anomalies and gravity disturbances are derived. The gravity anomaly (Dg) is defined as the scalar difference between the Earth’s gravity on the geoid and normal gravity on the surface of the reference ellipsoid. Gravity disturbance (dg) is defined as the difference between the actual gravity magnitude measured on Earth and its equivalent normal gravity in the normal gravity field for the same point. The changes and magnitudes of the calculated quantities are compared. Changes such as the observed gravity and height data, observed gravity changes versus calculated normal gravity changes, normal gravity on ellipsoid versus geographic latitude, observed gravity changes versus latitude changes, Bouguer gravity anomaly and gravity disturbance versus latitude and elevation, free-air reduction and Bouguer gravity reduction versus latitude and elevation have been investigated.

VARIATIONS IN MAGNETIC PROPERTIES PROPAGATION IN STEEL SHELL STRUCTURE CAUSED BY WELDING (PART 2)

The first stage of the research involves analyzing primary and secondary acoustic wave propagation behavior. The results of the first stage suggest that the properties of shell structures used at every stage of the experiment are distributed unevenly along the generator lines and across the width of the test pipes. In order to conduct a comparative study of properties, the authors of the research introduce the heterogeneity parameter. During the experiment, the parameter is changing locally within two orders of magnitude, even in case of test pipes in their initial state. Equal sensitivity to heterogeneities across steel products is found in its magnetic properties. As numerous studies prove, analyzing variations in magnetic properties makes it possible to detect flaws and areas of their concentration. This method can also be used to estimate the remaining service life. This is a crucial aspect to consider when assessing properties and using the findings to develop digital twins of shell structures. The authors focus on identifying acoustic and magnetic signals coming from flawed shell structures and weld joint areas in particular. For this purpose, magnetic memory method and X-ray analysis are used. It is found that both normal and tangential magnetic field components are sensitive to structural heterogeneities across a steel product. The combination of magnetic memory method and X-ray analysis make it possible to determine how typical weld joint flaws occurring during welding affect the magnetic properties. Sufficient measurements are required for statistical analysis of the findings. It is also possible to introduce further criteria in order to import metal properties correctly into the modelling program using numerical methods.

DESIGNING COLLABORATIVE AUGMENTED REALITY ACTIVITIES WITH OLDER ADULTS IN LONG TERM CARE

Abstract Loneliness is common among older adults in long term care (LTC) settings. Interactive communication technologies hold great promise in reducing loneliness but require design and evaluation studies. As part of a larger study on use of head mounted display augmented reality (HMD-AR) to connect older LTC adults with family members, we conducted a participatory design study to a) identify and design HMD-AR multi-user activities and b) address barriers found with LTC residents when interacting with HMD-AR. Results: Laboratory testing was conducted with 23 older adults with normal cognition (ages 65 to 93, 6 men) and field testing with iterative feedback cycles with 8 older adults with impaired mobility and cognition (ages 54 to 87, 2 men, 4 with stroke) that resulted in prototype development and testing of three activities: playing checkers, decorating a fireplace, and eating a meal. Challenges successfully addressed through technological innovations included: 1) enhancing perceptions and ease of interacting with photorealistic avatars, 2) providing various techniques to allow older adults to view and move AR objects despite cognitive and functional impairments (e.g., visual-perceptual impairments; limited dexterity), 3) using visual aids and voice commands, 4) developing visual adaptations for central vision and color detection impairments, and 5) creating tutorials and help guides for learnability and remembrance. Sessions lasted for 30 minutes and no adverse effects were noted with prolonged or repeated HMD-AR use. All enjoyed the HMD-AR activities. Conclusion: HMD-AR can be successfully adapted for use by older adults with multiple cognitive and physical impairments.