Line Elements Research Articles

Complexity measurement of line element on nautical chart considering local difference

Complexity measurement of line element on nautical chart considering local difference

Lagrangian Solution of Schwarzschild-like Metric for an ‎Elliptical Object

Lagrangian method applied as well as tensor method, for a linear transformed geodesic line element of Schwarzschild-like The ‎Lagrangian method was applied for a linearly transformed geodesic line element of a Schwarzschild-like solution instead of ‎the tensor method. The solution shows that it is not only valid for spherical objects but also it is more comprehensive for ‎elliptical celestial objects. Two types of kinetic and potential energy are the basis of the calculation. Hamiltonian and ‎Lagrangian equality show that the problem has no potential energy. With this transformed geodesic line element, we obtained ‎a new coefficient for the meridional advance of an experimental particle in Schwarzschild spacetime in terms of period, ‎eccentricity, and mean distance. This new perigee equation is not only valid for the Schwarzschild metric (for a spherical ‎object), but also more accurate for the Schwarzschild-like metric (for elliptical objects).‎

발렌티노 패션쇼메이크업에 나타난 조형원리적 특성에 관한 고찰

The purpose of this study is to discuss the methodology of creative activities of various fashion show make-up by understanding the formative principles based on formative elements. The research method was combined with theoretical and empirical studies. The scope of the study was limited to the make-up that appeared in the Valentino fashion show from the 2020 S/S to the 2022 F/W by Ready to Wear. As a result of the study, 20S/S fashion show makeup shows the principle of balanced symmetry and emphasis using the texture elements of gold color and pearl and the elements of line. and The fashion show makeup of 20F/W showed the principle of balanced symmetry and emphasis using strong image black color and sharp shipping formative elements. The formative elements used in fashion showmake-up of 21S/S visualized sharp shipping elements as formative principles of balance, symmetry and emphasis. and The fashion show make-up of 21F/W shows formative characteristics as the principle of emphasis along with the principle of balance and symmetry of the elements of face and line. The fashion showmake-up of 22S/S is designed to express sporty sensual beauty as the principle of emphasizing the balance symmetry and the toughness of blackish color. The fashion show makeup of 22F/W gives visual harmony as the principle of emphasis using elements of color and the principle of balanced symmetry.

STUDY OF ICE FORMATION PROCESSES ON OVERHEAD POWER LINES AND DEVELOPMENT OF SYSTEMS TO COMBAT THIS PHENOMENON

Icing on the wires of overhead power lines is a big problem to maintain their integrity. The process of icing wires leads to a significant increase in their mass and, accordingly, to large overloads on the wire and electric supports. Exceeding the loads above the permissible ones can cause great damage to power lines. Wires, cables can break, fittings can be damaged and even lead to collapse of electrical poles. At the same time, damage is caused from the undersupply of electricity. This damage may exceed the damage from damage to the elements of power lines. Ice on the wires usually appear in winter, especially when the warming is going to be replaced by a cold snap and the temperature fluctuates around zero. The problem can be exacerbated by strong wind loads. An increase in air humidity also accelerates the formation of an ice "coat" on wires and electrical poles. Under the most unfavorable conditions, the wall thickness of the “fur coat” of ice on the wire can reach more than 70 mm. Such an ice coat can lead to exceeding the maximum permissible loads and damage to the power line, as well as damage from a power outage. The mechanism of ice formation on overhead power lines, as well as negative damage to power lines and high-voltage pylons under the action of ice load, has been studied. An analysis of the known methods of dealing with ice on power lines has been carried out. An innovative device for combating icing formations is proposed. The advantage of the proposed device is the ability to operate in two modes: vibrating and shock-shaking, which expands its functionality. In preventive mode, the device operates continuously due to the interaction with alternating current flowing through the wires of power lines in the normal mode of their operation, without the need for shutdown for maintenance, which gives the electromechanical interactions of devices with the wire of the power line a vibrational character and ensures the continuity of the process of removing water drops from the wires at an early stage before ice formation. Thus, in the preventive mode of operation of the power line, the causes of icing of the wires are eliminated, and not its consequences, which eliminates the need to shut down for maintenance, and reduces the required costs of resources and energy.

Vibration sensor for monitoring systems of construction elements of high-voltage power lines

PURPOSE. To develop a differential parametric inductive transducer of vibration values into an electrical signal, which is a vibration displacement sensor (DV) with a new principle of operation. Theoretically substantiate the performance of the proposed DV. To develop a new system for vibroacoustic monitoring of the technical condition of overhead power transmission line (TL) supports using the proposed DV. METHODS. When solving this goal, the theory of parametric transducers and the main provisions of the theory of vibration diagnostics were used. RESULTS. The design feature of the developed DV is the absence of an excitation coil, and its functional elements form a full-fledged measuring bridge, the arms of which include interturn capacitances of the windings of the first and second measuring coils, as well as capacitances formed by a metal cylindrical electrode with a coaxially located inside it ferromagnetic rod and the first lower rows of wire windings of the measuring coils. The bridge circuit operates in a resonant mode, which ensures the high sensitivity of the proposed sensor, and the quadrature conversion of the information signal provides the necessary level of noise immunity. The received signal is a functional dependence of the output voltage of the measuring bridge on the magnitude of external vibrations, the characteristics of the temporary realizations of which reflect the degradation processes occurring in the power transmission line supports. CONCLUSION. The proposed system for monitoring the integrity of power transmission line supports is actually a distributed real-time sensor network that implements PLC technology. The DV of each sensor module registers microvibrations of the structural elements of the corresponding power transmission line support, caused by natural disturbing factors during their operation, and converts them into an electrical information signal, which forms the basis of monitoring information about the current state of the power transmission line support structural elements.

Generalized Hayward spacetimes: Geometry, matter, and scalar quasinormal modes

Bardeen's 1968 idea of a regular black hole spacetime was revived by Hayward in 2006 through the construction of a new example of such a geometry. Later it was realized by Neves and Saa, that a wider, two-parameter class exists, with Bardeen and Hayward spacetimes as special cases. In this article, we revisit and generalize the Hayward spacetime by applying the Damour-Solodukhin (DS) prescription. Recalling the DS suggestion of a deformed Schwarzschild spacetime where ${g}_{tt}=\ensuremath{-}(1\ensuremath{-}\frac{2{M}_{1}}{r})$, ${g}_{rr}={(1\ensuremath{-}\frac{2{M}_{2}}{r})}^{\ensuremath{-}1}$ and ${M}_{1}\ensuremath{\ne}{M}_{2}$, we propose a similar deformation of the Hayward geometry. The ${g}_{tt}$ and ${g}_{rr}$ in the original Hayward line element remain functionally the same, albeit with changes introduced via differently valued metric parameters, following the DS idea. This results in a plethora of spacetime geometries, known as well as new, and including singular black holes, wormholes or regular black holes. We first study the geometric features and matter content of each of such spacetimes in some detail. Subsequently, we find the scalar quasinormal modes corresponding to scalar wave propagation in these geometries. We investigate how the real and imaginary parts of the quasinormal modes depend on the values and ranges of the metric parameters used to classify the geometries. Finally, we argue how our results on this family of spacetimes suggest their utility as black hole mimickers.

Determination of load transfer characteristics to connections between cold-formed steel truss and supporting system

PurposeRecently, the utilization of cold-formed steel (CFS) roof truss systems and different types of other combination structural support systems, such as concrete or hot-rolled steel support, becomes more frequently used. This paper aims to identify the load transfer characteristics of three different design details for cold-formed truss to supporting system connections and to propose simplified modelling approach for practices.Design/methodology/approachSimplification modelling of connection design could be proposed for practical purpose based on the load transfer characteristics obtained from detailed study using finite element method. A cold-formed roof truss system with connection is modelled using line elements. However, the supporting system is not modelled in this work. Three types of connection involve, which are five pieces of CFS L-angle brackets, one-piece of CFS L-angle brackets and three types of bolts connection are modelled.FindingsThe results of analysis show that the connections located on the loaded side experienced higher reactions than those far from loaded side. From the result, it is also found that the option of “Fixed But” support condition in STAAD.Pro with translational degree of freedom being restrained is the most suitable way to represent the CFS L-angle brackets design for Type 1 connection for use in truss modelled using line elements.Originality/valueSuch increase in usage necessitates an appropriate connection detailing depending on the behaviour of the connection.

Raster Map Line Element Extraction Method Based on Improved U-Net Network

To address the problem of low accuracy in line element recognition of raster maps due to text and background interference, we propose a raster map line element recognition method based on an improved U-Net network model, combining the semantic segmentation algorithm of deep learning, the attention gates (AG) module, and the atrous spatial pyramid pooling (ASPP) module. In the proposed network model, the encoder extracts image features, the decoder restores the extracted features, the features of different scales are extracted in the dilated convolution module between the encoder and the decoder, and the attention mechanism module increases the weight of line elements. The comparison experiment was carried out through the constructed line element recognition dataset. The experimental results show that the improved U-Net network accuracy rate is 93.08%, the recall rate is 92.29%, the DSC accuracy is 93.03%, and the F1-score is 92.68%. In the network robustness test, under different signal-to-noise ratios (SNRs), comparing the improved network structure with the original network structure, the DSC improved by 13.18–17.05%. These results show that the network model proposed in this paper can effectively extract raster map line elements.

On the Quaternion Transformation and Field Equations in Curved Space-Time

In this paper, we use four-dimensional quaternionic algebra to describe space-time geodesics in curvature form. The transformation relations of a quaternionic variables are established with the help of basis-transformations of quaternion algebra. We deduce the quaternionic covariant derivative that explains how the quaternion components vary with scalar and vector fields. The quaternionic metric tensor and the geodesic equation are also discussed to describe the quaternionic line element in curved space-time. We examine a quaternionic metric tensor equation for the Riemannian Christoffel curvature tensor. We present the quaternionic Einstein’s field-like equation, which indicates that quaternionic matter and geometry are equivalent. Relevance of the work:In recent decades, hypercomplex algebra, viz., quaternion and octonions, has been widely used to explain various branches of physics. In this way, we have investigated quaternionic transformations and field equations in curved space-time. The present novel work will help to explain the characteristics of the curved space-time universe in terms of quaternion algebra. It can also be used to describe quaternionic gravitational waves, the black hole formulation, and so on.

Hidden symmetries from distortions of the conformal structure

It is well established that the mass parameter breaks the conformal symmetries in the case of geodesic motion. The proper conformal Killing vectors cease to generate conserved charges when non-null geodesics are considered. We examine how the introduction of the mass is actually related to the appearance of appropriate distortions in the conformal sector, which lead to new conservation laws. As a prominent example, we use a general pp-wave metric, which exploits this property to the maximum. We study the necessary geometric conditions, so that such types of distortions are applicable. We show that the relative vectors are generators of disformal transformations and prove their connection to higher order (hidden) symmetries. Except from the pp-wave geometry, we also provide an additional example in the form of the de Sitter metric. Again, the proper conformal Killing vectors can be appropriately distorted to generate conserved quantities for massive geodesics. Subsequently, we proceed by introducing an additional symmetry breaking effect. The latter is realized by considering a Bogoslovsky type of line element, which involves a Lorentz violating parameter. We utilize once more the pp-wave case as a guide to study how the broken symmetries---this time also related to Killing vectors---are substituted by distortions of the original generators. We further analyze and discuss the necessary geometric conditions that lead to the emergence of these distortions.

Nonsingular spherically symmetric black-hole model with holonomy corrections

We present a covariant model of a spherically symmetric black hole with corrections motivated by loop quantum gravity. The effective modifications, parametrized by a positive constant $\ensuremath{\lambda}$, are implemented through a canonical transformation and a linear combination of the constraints of general relativity, in such a way that the theory remains free of anomalies and general relativity is recovered for $\ensuremath{\lambda}=0$. In addition, the corresponding metric is constructed in a fully covariant way to ensure that gauge transformations on phase space correspond to coordinate changes. The solution for each gauge choice provides a chart and corresponding line element of a spacetime solution whose geometry is unambiguously determined in terms of the parameter $\ensuremath{\lambda}$ and a constant of motion $m$. For positive values of $m$, the solution is asymptotically flat and contains a globally hyperbolic black-hole/white-hole region with a minimal spacelike hypersurface that replaces the Schwarzschild singularity. The corresponding exterior regions are isometric and, in particular, allow the computation of the Arnowitt-Deser-Misner mass. The procedure to obtain the global causal structure of the solution yields also its maximal analytic extension.

Analysis of repeat elements in the Pristionchus pacificus genome reveals an ancient invasion by horizontally transferred transposons

BackgroundRepetitive sequences and mobile elements make up considerable fractions of individual genomes. While transposition events can be detrimental for organismal fitness, repetitive sequences form an enormous reservoir for molecular innovation. In this study, we aim to add repetitive elements to the annotation of the Pristionchus pacificus genome and assess their impact on novel gene formation.ResultsDifferent computational approaches define up to 24% of the P. pacificus genome as repetitive sequences. While retroelements are more frequently found at the chromosome arms, DNA transposons are distributed more evenly. We found multiple DNA transposons, as well as LTR and LINE elements with abundant evidence of expression as single-exon transcripts. When testing whether transposons disproportionately contribute towards new gene formation, we found that roughly 10–20% of genes across all age classes overlap transposable elements with the strongest trend being an enrichment of low complexity regions among the oldest genes. Finally, we characterized a horizontal gene transfer of Zisupton elements into diplogastrid nematodes. These DNA transposons invaded nematodes from eukaryotic donor species and experienced a recent burst of activity in the P. pacificus lineage.ConclusionsThe comprehensive annotation of repetitive elements in the P. pacificus genome builds a resource for future functional genomic analyses as well as for more detailed investigations of molecular innovations.

The ecology of palm genomes: repeat-associated genome size expansion is constrained by aridity.

Genome size varies 2400-fold across plants, influencing their evolution through changes in cell size and cell division rates which impact plants' environmental stress tolerance. Repetitive element expansion explains much genome size diversity, and the processes structuring repeat 'communities' are analogous to those structuring ecological communities. However, which environmental stressors influence repeat community dynamics has not yet been examined from an ecological perspective. We measured genome size and leveraged climatic data for 91% of genera within the ecologically diverse palm family (Arecaceae). We then generated genomic repeat profiles for 141 palm species, and analysed repeats using phylogenetically informed linear models to explore relationships between repeat dynamics and environmental factors. We show that palm genome size and repeat 'community' composition are best explained by aridity. Specifically, Ty3-gypsy and TIR elements were more abundant in palm species from wetter environments, which generally had larger genomes, suggesting amplification. By contrast, Ty1-copia and LINE elements were more abundant in drier environments. Our results suggest that water stress inhibits repeat expansion through selection on upper genome size limits. However, elements that may associate with stress-response genes (e.g. Ty1-copia) have amplified in arid-adapted palm species. Overall, we provide novel evidence of climate influencing the assembly of repeat 'communities'.

Investigation of the influence of bundled conductor capacitance on power loses associated with corona discharge

The determining factor for the presence of a corona is the value of the charge of the wire, which determines the intensity of the electric field. Quantitative characteristics of the charge value of the line phase depend on the capacity and voltage. If the influence of voltage on corona losses has been studied by many authors, the influence of capacity is practically not studied. This is primarily due to the fact that the constructive implementation of the split phase of the overhead line was very carefully determined by regulatory documents. In our opinion, today there are all possibilities for changing the designs of phases and, accordingly, their capacities. This became possible thanks to a change in approaches to the design of the structure of the phase wire on the substation. Determination of the electric capacity of the overhead line with bundled conductors is quite often performed using equivalent parameters, such as equivalent suspension height and equivalent radius. This approach makes it possible to obtain average values of the phase capacity of the overhead line. For a detailed analysis of the effect of capacity on corona losses, it is necessary to determine more reliable values of capacities and use them in calculations of corona losses. The capacity of the phase is determined by the geometric dimensions of the split phase. The obtained results indicate a very strong dependence of corona losses on the capacity of the split phase. When approaching a grounded object, the phase capacity can significantly increase. A vivid example of such an increase is the approach of bundled conductors to the elements of overhead line supports. The distances to the ground in this case will be smaller than the equivalent height of the suspension, which is used in the calculations of the specific losses per crown to determine the capacity of the phases of the overhead line. It is necessary to take into account possible changes in the capacity of the split phase at the stage of designing the overhead line. Another result of the calculations was a much greater influence of the capacity of the middle phase on the amount of losses per corona. This makes it possible to reduce corona losses due to the appropriate design of the middle phase of the overhead line, for example, by changing its splitting radius.

When might we break the rules? A statistical analysis of aesthetics in photographs.

High-quality photographs often follow certain high-level rules well known to photographers, but some photographs intentionally break these rules. Doing so is usually a matter of artistry and intuition, and the conditions and patterns that allow for rule-breaks are often not well articulated by photographers. This article first applies statistical techniques to help find and evaluate rule-breaking photographs, and then from these photographs discover those patterns that justify their rule-breaking. With this approach, this article discovered some significant patterns that explain why some high-quality photographs successfully break the common photographic rules by positioning the subject in the center or the horizon in the vertical center. These patterns included reflections, leading lines, crossing objects, ambiguous lines, implied lines, thirds line subjects, and busy foregrounds for center horizon photographs, and symmetry, circular-shaped objects, thirds line elements, gestalt, framing, leading lines, and perspective lines for center subject photographs.

Anisotropic spacetimes in f(T, B) theory II: Kantowski–Sachs Universe

In the context of the modified teleparallel f(T, B) theory of gravity, we consider a homogeneous and anisotropic background geometry described by the Kantowski–Sachs line element. We derive the field equations and investigate the existence of exact solutions. Furthermore, the evolution of the trajectories for the field equations is studied by deriving the stationary points at the finite and infinite regimes. For the $$f(T,B)=T+F\left( B\right) $$ theory, we prove that for a specific limit of the function $$F\left( B\right) $$ , the anisotropic Universe has the expanding and isotropic Universe as an attractor with zero spatial curvature. We remark that there are no future attractors where the asymptotic solution describes a Universe with nonzero spatial curvature.

Orbit Propagation and Lifetime Analysis of NARSSCUBE-2 Using High Precision Numerical Approach

Due to their short mission lifetime, Cube satellites launched in the last decades have increased the number of objects in Low Earth Orbits and the number of space debris. As a result, it is important to obtain accurate measurements of CubeSats trajectories in order to determine their decay and orbital lifetime and to avoid collisions with debris. In this paper, a special perturbation technique has been used as an orbit propagator in order to model orbital motion and predict the behavior of Cube satellites subjected to perturbations. This technique is a high-precision numerical approach via Cowell's formulation with adaptive step size Runge-Kutta-Fehlberg (RKF78) for numerical integration. The technique used is named SPC (Special Perturbation using Cowell's method). Orbit propagation and orbital decay evolution of NARSSCUBE-2 have been analyzed using appropriate orbital parameters derived from historic NORAD Two Line Element sets. The results from the SPC technique have been compared with the SGP4 analytical orbit propagator and then verified with the HPOP numerical orbit propagator from FreeFlyer® astrodynamics software. The accuracy of each propagator has been verified with the observation data. The SPC orbit propagator gives a higher accuracy of orbit prediction compared to SGP4 and closely matches with HPOP.

Covariant Space-Time Line Elements in the Friedmann–Lemaitre–Robertson–Walker Geometry

Most quantum gravity theories quantize space-time on the order of Planck length (ℓp ). Some of these theories, such as loop quantum gravity (LQG), predict that this discreetness could be manifested through Lorentz invariance violations (LIV) over travelling particles at astronomical length distances. However, reports on LIV are controversial, and space discreetness could still be compatible with Lorentz invariance. Here, it is tested whether space quantization on the order of Planck length could still be compatible with Lorentz invariance through the application of a covariant geometric uncertainty principle (GeUP) as a constraint over geodesics in FRW geometries. Space-time line elements compatible with the uncertainty principle are calculated for a homogeneous, isotropic expanding Universe represented by the Friedmann–Lemaitre–Robertson–Walker solution to General Relativity (FLRW or FRW metric). A generic expression for the quadratic proper space-time line element is derived, proportional to Planck length-squared, and dependent on two contributions. The first is associated to the energy–time uncertainty, and the second depends on the Hubble function. The results are in agreement with space-time quantization on the expected length orders, according to quantum gravity theories, and within experimental constraints on putative LIV.

An Autonomous Storage Optimization LRM Generation Strategy Based on Cascaded NURBS

Automatic control of intelligent vehicles depends heavily on accurate lane-level location information. The traditional digital map cannot meet the automatic driving requirements, and it is very difficult for lane-level road maps (LRMs) to achieve a good balance between the representation accuracy and data storage volume. To tackle this problem, we obtain the recursive definition of a lane line by analyzing road lanes using the fractal geometry theory. Subsequently, we construct a recursive feedback system and model it. On this basis, an autonomous storage optimization LRM generation strategy based on cascaded NURBS is devised. According to the input data density, this framework generates an LRM with the minimum data storage volume within the error constraint. It is mainly composed of two modules: (1) a random fractal and (2) an adaptive iteration memory optimizer, based on cascaded NURBS error feedback. First, the whole lane is divided into several meta lane line modules. Second, data sampling/interpolation is carried out iteratively according to the NURBS fitting error and symmetry of road geometry. In this way, the storage space used to store lane lines and other information is automatically optimized. Last, a simulation experiment is carried out by using a dataset obtained from a park. The simulation results show that the proposed method can achieve high accuracy and high storage efficiency. Under the constraint of a 0.1 m curve fitting error, the average memory demand of the lane line elements is less than 2.4 bytes/m.

ABOUT REQUIREMENTS TO PLUGGING MATERIALS AND TO TUBING TECHNOLOGY FOR THE CASING COLUMNS WORKING IN EXTREME CONDITIONS

The most vulnerable elements of the well lining is cement paste in injection wells and the lower parts of the intermediate and surface casings, which suggests the need for the study of additional requirements to plugging materials and lining technology of the specified lining elements. Analysis shows that the main number of workover happens for the share of injection wells, and the number of detected violations in injection wells which is more than an order of magnitude exceeds the corresponding figures for the production casing. Samples of cement stone, selected from the injection and production wells showed that in injection wells, the cement stone collapses in 4-5 years.The mechanism and kinetic process of destruction of cement stone under the influence of leaching was considered and the ways of increasing the durability of linings in injection wells were shown. Leaching corrosion processes in injection wells strengthens during the formation of cracks in the cement stone as a result of technological operation inside the casing string. The most dangerous technological operations are; perforation and deepening of the well. In order to obtain high-quality well anchoring, it is inevitable to regulate the basic properties of cement mortars with the help of various chemical reagents. At the same time, the filtration characteristics (water output and water separation), setting time, pumpability, rheological parameters, as well as the properties of the resulting stone require correction most often in grouting solutions It is shown that for plugging materials, the most preferred way to increase the resistance of grouting stone to dynamic loads is dispersed reinforcement, which can be effectively regulated by the most important characteristics of cement slurries and cement stone can be obtained from them. Studies have been conducted on the influence of basalt fiber and polyamide fiber on the basic physical and mechanical properties of the resulting stone, such as the strength of cement stone, deformation of cement stone during destruction, the specific impact strength of Portland cement stone, as well as the permeability of cement stone. Studies have shown positive results of the addition of basalt fiber at concentrations up to 2%.