Planar Elements Research Articles

Estetika Warna Kulit Manggis dalam Seni Lukis

The aesthetics of mangosteen skin color have unique characteristics compared to other synthetic colors. Aesthetic and dimensional, mangosteen skin color displays natural shades such as light brown, chocolate, brownish, red, purple, and blue. Painting using mangosteen peel is a creative process that begins with picking mangosteen fruit from the garden. Coincidentally, the author became interested in scratching spontaneously. When he split a mangosteen fruit into two equal parts, the author used the mangosteen peel to create a graffiti on the canvas. This technique involves spontaneous movements of the fingers, pressing gently, moderately, and sometimes hard on the canvas. The resulting color effect appears naturally, according to the intensity of the finger movement when scratching the mangosteen skin on the canvas. The painting method using mangosteen peel is carried out spontaneously, following the stages of art creation: existence, exploration, experimentation and evaluation. The creation of paintings using mangosteen peel reflects a creation process that uses fine art elements of light, point, line, space, plane, color, texture and composition. The resulting works of art are titled as line aesthetics: Line Aesthetic 1, Line Aesthetic 2, Line Aesthetic 3, and so on. The use of mangosteen peel color as an alternative medium in painting is driven by the need for creativity to achieve works of art that are new, high quality, meaningful and have high harmonious value.

Design and Analysis of Yoshimura Tubular Origami Mechanisms

The Yoshimura tubular origami mechanism possesses numerous advantageous properties and, when integrated with advanced material technologies, can be applied across various engineering disciplines. However, current research on Yoshimura origami predominantly focuses on centrally symmetric tubular origami mechanisms, which restricts the structural forms and motion patterns of these mechanisms. Drawing inspiration from the biological concept of “morphological variation,” we propose a novel tubular origami mechanism based on the Yoshimura pattern, which is the main contribution of this research. We analyze the Yoshimura planar crease elements and introduce both heterocellular and homocellular tubular origami mechanisms. Furthermore, we establish the origami topology matrices for the Yoshimura tubular origami mechanisms. This research also investigates complex motion forms that differ from traditional Yoshimura origami mechanisms, including macroscopic twisting and compound movements, thereby providing an intuitive design approach and extensive structural guidance for research in Yoshimura tubular origami engineering. Based on the tubular origami mechanism, we created an origami robot and investigate its motion characteristics.

Coherent characteristics of broadband and extended light sources based on the Twyman–Green interferometer

The Twyman–Green interferometer, as a representative type of interferometric structure, possesses unique advantages in the field of interferometry due to its adjustable single optical path characteristic. However, using a laser as the light source for the Twyman–Green interferometer, with its long coherence length, can result in noisy fringes when measuring planar elements, including multiple surface interference fringes and speckle noise. To address these issues, this paper proposes the use of broadband extended light source as the coherent light source in the Twyman–Green interferometer to achieve short coherent source illumination, thereby eliminating interference fringes and coherent noise. This paper theoretically derives the coherence characteristics of broadband extended light sources and, in particular, quantitatively analyzes the influence of the thickness difference of glass in the Twyman–Green dual optical paths on the contrast of the interference fringe. The corresponding theoretical expressions for interference intensity are derived, and the validity of these theoretical findings is demonstrated through simulation analysis and experimental verification. This innovative research, to our knowledge, significantly supplements the existing coherence theory of light sources, offering substantial theoretical research insights and practical engineering applications.

A simple model for faceted topographies at normal faults based on an extended stream-power law

Abstract. Mountain fronts at normal faults are often faceted in the sense that they contain strikingly planar surface elements that follow the surface trace of the fault. Since the dip angle of the facets is typically much lower than the dip angle of the fault, it is clear that the facets are not just the exhumed footwall but have been eroded considerably. It has also been shown that a constant erosion rate in combination with a constant rate of displacement can explain the occurrence of planar facets. Quantitatively, however, the formation of faceted topographies is still not fully understood. In this study, the shared stream-power model for fluvial erosion and sediment transport is used in combination with a recently published extension for hillslopes. As a major theoretical result, it is found that the ratio of the tangents of the facet angle and the dip angle of the fault as well as the ratio of the baseline length and horizontal width of perfect triangular facets mainly depend on the ratio of the horizontal rate of displacement and the hillslope erodibility. Numerical simulations reveal that horizontal displacement is crucial for the formation of triangular facets. For vertical faults, facets are rather multiangular and much longer than wide. While the sizes of individual facets vary strongly, the average size is controlled by the ratio of hillslope erodibility and fluvial erodibility.

Experimental study on the mechanical properties of non-reinforced UHPC element under biaxial stress states

The ultra high performance concrete (UHPC) has been gradually applied in bridge and building engineering to replace normal concrete as a new type of cementitious material. The biaxial strength criteria of UHPC play an essential role in engineering design and research. However, the experimental research on biaxial strength of UHPC is still lacking. In this study, four groups of biaxial loading tests on UHPC planar elements were carried out, using the Planar Bi-directional Element Tester (PBET) developed by Tsinghua University, including biaxial compressive test, biaxial tensile test, biaxial tension-compression sequential test, and biaxial tension-compression proportional test. The biaxial stress ratio is also studied as a key parameter. Based on the test results, the typical failure modes under different biaxial loading conditions as well as the biaxial strength criteria of UHPC are revealed. Taking the biaxial strength criteria of normal concrete as a reference, the complete biaxial strength envelope equations of UHPC are finally derived.

Programmable orientation of blue phase soft photonic crystal

Understanding the structure formation and its underlying physical mechanism is a fundamental topic in condensed matter systems, with both academic and practical implications. Soft matter is playing a remarkable role in current era of information explosion, demonstrating enormous potential in integrated functional photonics. As unique soft photonic crystals with cubic symmetries, not only liquid crystalline blue phases (BPs) have circularly polarized selective reflection and ultra-fast electro-optical response, but also their three-dimensional photonic structures increase degrees-of-freedom for multiplexed optical modulation. In the thriving field of soft-matter-based photonics, precise and programmable engineering of BP crystal orientation is of vital importance for planar optical elements, which remains a challenging task due to the complexity of the nucleation process as well as the interaction between the BP building blocks and the boundary conditions. Aiming to gain a comprehensive understanding of how to tailor the orientation of BP crystals for the photonic applications of next generation, here we discuss the solutions for uniformity improvement and orientation control of BP crystals, about which a few of examples in combination with the underlying mechanisms are explained. In addition, the remaining challenges and the efforts that are expected are also reviewed. We expect this work provides a deeper understanding of phase transitions and resulting structures in soft crystals, which may open encouraging perspectives for their applications in photonics, biosensing, interfacial, and chemical engineering.

A Planar Feature-Preserving Texture Defragmentation Method for 3D Urban Building Models

Oblique photogrammetry-based 3D modeling is widely used for large-scale urban reconstruction. However, textures generated with photogrammetric techniques often exhibit scattered and irregular characteristics, which lead to significant challenges with texture seams and UV map discontinuities, increasing storage requirements and affecting rendering quality. In this paper, we propose a planar feature-preserving texture defragmentation method designed specifically for urban building models. Our approach leverages the multi-planar topology of buildings to optimize texture merging and reduce fragmentation. The proposed approach is composed of three main stages: the extraction of planar features from texture fragments; the employment of these planar elements as guiding constraints for merging adjacent texture fragments within a two-dimensional texture space; and an enhanced texture-packing algorithm designed for more regular texture charts to systematically generate refined texture atlas. Experiments on various urban building models demonstrate that our method significantly improves texture continuity and storage efficiency compared to traditional approaches, with both quantitative and qualitative validation.

Modeling the Dynamic Properties of Multi-Layer Glass Fabric Sandwich Panels.

Sandwich panels are key components of many lightweight structures. They are often subjected to time-varying loads, which can cause various types of vibrations that adversely affect the functionality of the structure. That is why it is of such importance to predict the dynamic properties of both the panels and the structures made of them at the design stage. This paper presents finite element modeling of the dynamic properties (i.e., natural frequencies, mode shapes, and frequency response functions) of sandwich panels made of glass fabric impregnated with phenolic resin. The model reproducing the details of the panel structure was built using two-dimensional, quadrilateral, isoparametric plane elements. Afterwards, the model was subjected to an updating procedure based on experimentally determined frequency response functions. As a result, the average relative error for natural frequencies achieved numerically was 5.0%. Finally, a cabinet model consisting of the analyzed panels was built and experimentally verified. The relative error between the numerically and experimentally obtained natural frequencies was on average 5.9%.

Enhanced Crystallinity of SrTiO3 Films on a Silicon Carbide Substrate: Structural and Microwave Characterization

Thin films of strontium titanate, which reveal high structure quality and tunable properties prospective for microwave applications at room temperature, were grown on a semi-insulating silicon carbide substrate using magnetron sputtering for the first time. The films’ growth mechanisms were studied using medium-energy ion scattering, and the films’ structures were investigated using X-ray diffraction. The electrical characteristics of planar capacitors based on strontium titanate films were measured at a frequency of 2 GHz using a high-precision resonance technique. It is shown that the tendency to improve the crystalline structure of strontium titanate film with an increase in the substrate temperature is most pronounced for films deposited at elevated working gas pressure under low supersaturation conditions. Planar capacitors formed on the basis of oriented SrTiO3 films on silicon carbide showed tunability n = 36%, with a loss tangent of 0.008–0.009 at a level of slow relaxation of capacitance, which is significantly lower than the data published currently regarding planar tunable ferroelectric elements. This is the first successful attempt to realize a planar SrTiO3 capacitor on a silicon carbide substrate, which exhibits a commutation quality factor more than 2500 at microwaves.

Allowable surface temperature of ceiling heating based on radiant temperature asymmetry

Radiant temperature asymmetry as one of the criteria for local thermal discomfort has an influence on the practical design of the heating system, as people are most sensitive to the radiant heating of the top of the head. The paper presents the determination of the allowable surface temperature of the heated ceiling based on the theoretical calculation using the angle factors and taking into account the allowable the radiant temperature asymmetry according to the standard values of 5 and 7 K. In practice, the radiation temperature asymmetry is determined by measuring two radiant temperatures. In this paper, the measurement of radiant temperature asymmetry is measured in an experimental room with a heated ceiling and the results are compared with the theoretical calculation procedure. The paper points out the differences between the measured and calculated values of the radiant temperature asymmetry. Based on the analyses, the allowable ceiling temperatures for radiant heating have been determined for different room geometries so that the radiant temperature asymmetry for thermal comfort categories A, B is actually observed. A new correlation has been established to determine the allowable surface temperature of the radiant ceiling as a function of the angle factor between the small plane element and the ceiling. For practical use, the correlation has been adjusted for typical geometric cases without the need for calculation of angle factors. Maximum ceiling surface temperatures are graphically displayed without causing thermal discomfort. Conversely, in large rooms with a heated ceiling, the ceiling surface temperature is severely limited, precisely because of the potential for thermal discomfort due to radiant temperature asymmetry.

Millimeter micro‐coaxial beam steering array for high‐speed satellite communications

AbstractWide‐band low‐loss passive beam steering array presents to be essential part of the RF front‐ends for high‐speed detection during deep space exploration missions. In this letter, the copper‐based additive manufacturing technology is proposed for the implementation of low‐profile (~0.1λ) antenna design. Adopting the micro‐coaxial line as the basic design unit enables wide bandwidth design. In addition, the broadband designs of Butler matrix, planar antenna element, and transmission transitions are proposed, respectively. The miniaturization of the metallic patch antenna is realized using a double slotted design, ensuring an array space of ~0.5λ, which beneficial for the low‐lobe beam steering. Experimental results show that the antenna array with an overall size of 39 × 29 × 0.5 mm presents four beams located at ±14° and ±43°, respectively. The bandwidth of return loss better than −10 dB ranges from 65 to 71 GHz. The measured result matches well with the simulated ones, which makes its potential operation for satellite applications.

Digital composite lattice materials for fast but robust assembly

The unique and complex architecture of lattice materials enable their excellent mechanical properties and multifunctionality, but how to realize their efficient production remains a challenge for large-scale structural application. In this study, a discrete assembly strategy was developed for lattice materials with planar elements (termed as clips) and a newly proposed joint design inspired by Chinese traditional mortise and tenon art. The clips were prepared through conventional mechanical cutting or additive manufacturing, and the assembled lattice materials were respectively tested. Different failure modes were observed in the clips but joint failure rarely occurred. Future application of the assembled digital lattice composites for emergency rescue scenarios was examined, where their portability and shape customization advantages fully revealed.

A Broadband Multi‐Channel Metasurface for Decoupling of Phase and Polarization

AbstractDecoupling of phase and polarization is significant for multidimensional light manipulation. However, this requires traditional cascaded and parallel optical elements, resulting in a bulky and complex system. Metasurfaces can potentially replace complex optical modules as novel ultrathin planar optical elements. Herein, an ultrathin single‐layer metasurface is proposed to decouple the phase and polarization based on the Pancharatnam–Berry phase. The rotation angles of the two nanofins are employed to manipulate the phase and polarization independently, significantly simplifying the design process. Diffraction‐limited focusing with a degree of linear polarization higher than 95% is achieved for wavelengths in the 405–633 nm range. Furthermore, a metasurface can arbitrarily manipulate the relative intensity between different channels. The intensity ratio is adjusted from 0.12 to 6.62. These results will pave the way for miniaturized, integrated, and multi‐channel optical elements.

Analysis of involute-curve geometry using position gradients: Application to gear-tooth profile

This paper examines using non-rational polynomials to approximate the involute-curve geometry, which is fundamental in the design of gear systems. The parametric form of the involute curve in terms of an involute-angle parameter is first presented. To be able to compare the analytical geometry results and numerical results obtained using the finite-element (FE) method for describing the geometry, the relationship between the involute-angle parameter and the FE spatial coordinate is defined. A new relationship between the involute-curve arc length and the coordinate used in the FE parameterization is also developed. To this end, the involute-curve equation is used to determine the involute-angle parameter at the intersection with circles with arbitrary radii including the gear pitch, addendum, and base circles. The parameter relationship allows defining the nodal position-gradient vectors defined by differentiation with respect to the FE spatial coordinate from involute-curve tangent vector. Two procedures for determining the left involute curve from the right involute curve of the gear tooth are described. In the first procedure, a coordinate transformation based on Rodrigues transformation with axis of rotation defined by the tooth-center line is used; while in the second procedure, the analytical expression of the left involute curve is defined using the gear-tooth thickness at the base circle. A general procedure for determining the position gradients for a given geometry obtained from analytical curves or using imaging techniques is introduced. Such a procedure can be used in case of worn gear teeth that cannot be described by simple functions. A planar rectangular element based on the absolute nodal coordinate formulation (ANCF) is used to approximate the gear-tooth geometry. While the involute geometry cannot be described exactly using non-rational polynomials, the analysis and results of this investigation demonstrate that the FE solution leads to accurate geometry results, demonstrating the potential of using the position gradients in future strength-calculation studies.

Numerical study on the effect of SLWR buoyancy configuration on pipe-soil interaction based on co-rotational method

The buoyancy module installed on the steel lazy-wave riser makes the riser locally S-shaped, which weakens the motion transmission from the top to the bottom but makes the pipe-soil interaction more susceptible to the buoyancy configuration. In this study, a two-dimensional planar static numerical model considering the riser global motion coupled with the nonlinear seabed interaction is developed. The planar co-rotating beam element is established based on the co-rotating coordinate method, the vertical soil resistance is simulated by the semi-empirical pipe-soil interaction model. And the global displacement of the riser and the soil resistance of the seabed are coupled in the co-rotational framework by the principle of minimum potential energy. Finally, the parametric effects of buoyancy configurations and riser structural characteristics are analysed. The results show that the established numerical model is suitable for solving the vertical pipe-soil interaction between riser and nonlinear seabed. Compared with SCR, the maximum embedment depth of SLWR in the TDZ is reduced by 23.5%, and the maximum vertical soil resistance is reduced by 8.26%. In the two buoyancy configuration adjustment methods, increasing the buoyancy section length obviously changes the shape of SLWR, resulting in significant changes in the embedment depth and vertical soil resistance.

Experimental study of Double-Elliptic-Ring-based thermomechanical metamaterials’ behaviour

In recent years there has been increased interest in 3D thermomechanical metamaterials. The current work reports the design, fabrication and testing of a novel anisotropic anepectic metamaterial obtained by grafting inserts of a second material into a known auxetic structure, the Double Elliptic Ring (DER). While auxetics have a Negative Poisson's Ratio (NPR), anepectics combine this with a negative coefficient of thermal expansion (NTE). To avoid unnecessary time and material expenditure during the additive manufacturing (AM) stage, mechanical and thermal finite element simulations (FEA) were used as a tool to screen the multitude of possible design variants under consideration, thus aiding in rapidly determining the more promising geometries. To further increase the efficiency during AM, the selected structures were then assembled from planar elements, joined together with an adhesive. In the end, through the combination of two conventional materials – PVA and Nylon – of positive Poisson's ratio (PR) and coefficient of thermal expansion (CTE) organized in the DER architecture, it was possible to achieve the desired NPR and CTE behaviour along some directions, coupled with positive values in other directions. Experimental results revealed a correlation between PR values and the number of cells in the structure and showed that, while NPR values are essentially determined by the metamaterial's geometry, the induction of NTE results from a subtle interaction of geometry and the properties mismatch between the constitutive materials.

A Relationship Between Spin and Geometry

In physics, spin is often seen exclusively through the lens of its phenomenological character: as an intrinsic form of angular momentum. However, there is mounting evidence that spin fundamentally originates as a quality of geometry, not of dynamics, and recent work further suggests that the structure of non-relativistic Euclidean three-space is sufficient to define it. In this paper, we directly explicate this fundamentally non-relativistic, geometric nature of spin by constructing non-commutative algebras of position operators which subsume the structure of an arbitrary spin system. These “Spin-s Position Algebras” are defined by elementary means and from the properties of Euclidean three-space alone, and constitute a fundamentally new model for quantum mechanical systems with non-zero spin, within which neither position and spin degrees of freedom, nor position degrees of freedom within themselves, commute. This reveals that the observables of a system with spin can be described completely geometrically as tensors of oriented planar elements, and that the presence of non-zero spin in a system naturally generates a non-commutative geometry within it. We will also discuss the potential for the Spin-s Position Algebras to form the foundation for a generalisation to arbitrary spin of the Clifford and Duffin–Kemmer–Petiau algebras.

GPU-accelerated approach for 2D fracture analysis of structures combining finite particle method and cohesive zone model

The fracture analysis of structures typically involves strong discontinuity and nonlinear behaviors, and it requires fine meshing and small time steps, making it time-consuming. This study proposes an approach accelerated by graphics processing units (GPU) for two-dimensional (2D) fracture analysis of structures combining finite particle method (FPM) and cohesive zone model (CZM). Specifically, the equations of motion of particles are presented, and the internal forces of planar triangular elements are derived based on FPM. Subsequently, the internal forces of four-particle cohesive element are derived to describe the CZM, and the linear elastic stage, softening stage, and failure stage are depicted according to the traction-separation criteria. An explicit GPU-based FPM analysis strategy for structural fracture analysis is then developed, and the parallel solvers for particles, triangular elements, and cohesive elements are implemented. A quasi-static fracture analysis of a concrete beam and a dynamic fracture analysis of the Kalthoff problem is conducted to verify the effectiveness of the proposed approach. The obtained crack propagation path, load vs. displacement curves, and crack propagation speed are in good agreement with the experimental results and the results in the literature. The efficiency of the proposed approach is also investigated. The achieved maximum speedup ratio of the GPU-accelerated approach to the central processing unit (CPU)-based approach reaches around 24, and the achieved speedup ratio relative to the commercial finite element software Abaqus/Explicit reaches around 11.5, demonstrating the computational efficiency of the proposed approach.

ВПЛИВ СУЧАСНИХ ТЕНДЕНЦІЇ ВИКОРИСТАННЯ СОНЯЧНОЇ ЕНЕРГЕТИКИ НА ЕСТЕТИЧНІ ЯКОСТІ МІСТА

Energy independence remains a priority task for most European countries. Along with traditional energy sources, more and more attention is being paid to renewable energy usage. The best solution for city residents is the use of solar energy for the local needs of individual households. However, chaotic installation of solar panels on the roofs has a negative impact on the aesthetic qualities of urban environment. Many problems as well arise during installation of panels itself on the roof structure. After all, solar panels have significant weight, which usually was not taken into account when calculating the roof structure. The wind load, which is higher for planar elements, also was not taken into account, which can provoke negative consequences like destruction of an entire structure during exploitation. Key problem is that in most cases panels are being installed on the already existing roof and were not laid in the project. Conducted research has revealed the negative impact of voluntarily installed solar panels on aesthetic qualities of the city. Argued the importance of coordinating the installation of solar energy accumulating elements with the architecture of the building and the environment by selecting an appropriate shape, texture and color. Proved the need to foresee during the design process the use of solar panels in the construction of the roof and walls to partially supply buildings with energy at the local level. Envisaging solar panels at the design stage will avoid duplicating the roof profile, which will reduce the weight of the roof structure and extend its service life. The analysis of main methods for organizing the "solar roof" showed that the most appropriate, from an aesthetic point of view, is the use of solar roof tiles. Based on analysis of available materials for accumulating solar energy, it was found that today there is no manufacturer that provides a complete solar roof with all its elements (gutters, snow retainers, deaerators, ladders, etc.). However, it is possible to choose elements with the corresponding texture and color and combine roof elements from different manufacturers.

Inkjet Printing with (Semi)conductive Conjugated Polymers: A Review

Functional inkjet printing is an emerging manufacturing technology for the production of various planar elements and electronic devices. This technology offers affordable freeform and highly customizable production of thin film micron-scale elements on various substrates. Functional inkjet printing employs various inks based on organic and inorganic materials with diverse functional properties, and among them, conjugated polymers are of particular interest due to their electrical, photophysical, and electrochemical properties. This paper provides an overview of inkjet printing with conjugated (semi)conductive polymers, including the fundamentals of the technology and its scope, limitations, and main challenges. Specific attention is drawn to the synthesis and chemistry of these polymers in connection with the patterning and functional properties of the inks composed thereof. Practical aspects of this technology are also highlighted, namely the manufacturing capabilities of the technology and particular applications for the fabrication of various electronic elements and devices.