Equivalent Theory Research Articles

A seven-parameter high-order finite element model for multi-stable analysis of variable stiffness laminated shells

Variable angle fiber composites provide large design space for multi-stable structures. However, they require reliable numerical models to accurately predict their mechanical behavior characterized by a complex material response and large deformation. To this end, we propose an accurate yet efficient model for stability analysis of variable angle fiber laminated shells. In this model, first a seven-parameter shell formulation with Equivalent Single Layer theory, which is suitable for three-dimensional constitutive laws, is utilized to accurately characterize the large deformation. The fiber orientation angle is described by a linear variation from the center to the end of the shell. Then, to improve the accuracy and to reduce the computational cost, the spectral/hp element with high-order polynomial basis functions is adopted for discretization. Finally, complex nonlinear equilibrium paths are effectively tracked by the Riks method. By comparison with ABAQUS solutions, the proposed model shows to be efficient and accurate for variable angle fiber laminates under various conditions, in which both the buckling, the snap-through and tristability behaviors are studied. Moreover, variable angle fiber shells provide more design possibilities than straight fiber shells. By opportunely varying the fibers angle of each lamina, it is possible to control the stable states as well as to obtain multiple stable configurations (bi- and tri-stability).

Experimental Validation and Calibration of the Galvin Model with Artificial Tight Sandstones with Controlled Fractures

The study of fractures in the subsurface is very important in unconventional reservoirs since they are the main conduits for hydrocarbon flow. For this reason, a variety of equivalent medium theories have been proposed for the estimation of fracture and fluid properties within reservoir rocks. Recently, the Galvin model has been put forward to model the frequency-dependent elastic moduli in fractured porous rocks and has been widely used to research seismic wave propagation in fractured rocks. We experimentally investigated the feasibility of applying the Galvin model in fractured tight stones. For this proposal, three artificial fractured tight sandstone samples with the same background porosity (11.7% ± 1.2%) but different fracture densities of 0.00, 0.0312, and 0.0624 were manufactured. The fracture thickness was 0.06 mm and the fracture diameter was 3 mm in all the fractured samples. Ultrasonic P- and S-wave velocities were measured at 0.5 MHz in a laboratory setting in dry and water-saturated conditions in directions at 0°, 45°, and 90° to the fracture normal. The results were compared with theoretical predictions of the Galvin model. The comparison showed that model predictions significantly underestimated P- and S- wave velocities as well as P-wave anisotropy in water-saturated conditions, but overestimated P-wave anisotropy in dry conditions. By analyzing the differences between the measured results and theoretical predictions, we modified the Galvin model by adding the squirt flow mechanism to it and used the Thomsen model to obtain the elastic moduli in high- and low-frequency limits. The modified model predictions showed good fits with the measured results. To the best of our knowledge, this is the first study to validate and calibrate the frequency-dependent equivalent medium theories in tight fractured rocks experimentally.

SOFTWARE FOR INTERPRETING THE RESULTS OF VERTICAL ELECTRICAL SOUNDING IN THE FORM OF A THREE-LAYER GEOELECTRIC STRUCTURE

By monitoring the state of the grounding system, electrical engineering personnel must independently solve the problem of interpreting the results of vertical electrical sounding (VES) of the soil using their own knowledge and practical experience. During the interpretation, outdated palettes or expensive software complexes are used, which allow analyzing only two-layer soils. This leads to a large number of errors and inaccuracies in the assessment of the state of the grounding system and worsens their operation. In this regard, a program was developed for the interpretation of the results of the VES in the form of a three-layer geoelectrical structure. The program is implemented in the Delphi programming language and contains two parts: computational and graphic. The computational part of the program uses point source current, Hooke-Jives, equivalence and reliability theory methods to optimize the determination of geoelectric model parameters. The graphical part allows the user to visualize the obtained results and perform their analysis. To confirm the reliability of the developed program, a comparison of the results of the experimental measurement of the resistance of the grounding arrangmants with the results of the calculation using the program was made for 65 substations with a voltage class of 35 kV of one of the regional energy companies of Ukraine. The obtained results showed that the program gives reliable results and can improve the quality of monitoring the condition of grounding systems, and accordingly increase the reliability and safety of operation of electrical stations and substations.

Compliance verification method on CCAR 25.1443(c) for civil aircraft passenger oxygen system based on blood oxygen saturation

This paper generally introduces the compliance verification method on airworthiness regulation CCAR 25.1443(c) of popular passenger oxygen system on civil aircraft firstly, then technical interpretation on regulation CCAR 25.1443(c) <Minimum Mass Flow of Supplemental Oxygen> is demonstrated and method of satisfying this regulation in Top-Down design is analyzed. For those passenger oxygen system based on blood oxygen saturation which is not directly fulfill the requirement of the regulation, equivalent altitude theory is established to transform mean tracheal oxygen partial pressure required by the regulation to blood oxygen saturation index of equivalent altitude, and user’s blood oxygen saturation of these passenger oxygen system is equivalent or higher than that transformed from the regulation through actual human body physiological test and theoretical analysis from aviation physiology, then compliance to the airworthiness regulation is demonstrated by Equivalent Level of Safety. This paper gives the compliance verification method on the airworthiness regulation for those passenger oxygen system based on blood oxygen saturation on civil aircraft and this method have been used and gotten approval of the Authority for a type of civil aircraft. This paper also provides theoretical basis and test basis for further airworthiness regulation revising of the regulation CCAR25.1443(c).

Miniaturized Polarization-Insensitive Rectifying Metasurface for Powering Internet of Things Devices

In this paper, a miniaturized polarization-insensitive rectifying metasurface unit cell is proposed for powering electric devices of Internet-of-Things (IoT). The metasurface, an array of periodic unit cells, consists of two layers of substrate and three layers of metal. The metasurface unit cell is composed of eight asymmetric dipoles, which are arranged orthogonally and closely on both surfaces of the upper substrate. The strong coupling between dipoles induces extra reactive components, which makes the unit size be miniaturized to only 0.15 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . The miniaturization mechanism is analyzed by the equivalent circuit theory. The simulation results show that the harvesting efficiency for arbitrary polarized waves are higher than 90% from 2.2 to 2.7 GHz (20%). Being integrated with Schottky diodes at the proper position, the rectifying metasurface is designed. A 2 × 2 array with the size of 0.3 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.3 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> was fabricated and measured. The maximum harvesting-rectifying efficiency is 61% at 2.45 GHz under different polarization angles. When the power density is 8 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , 80 mW direct current (DC) power could be obtained.

Причинная связь в уголовном праве Германии

Criminal jurisprudence in Germany from the end of the 19th to the present day follows to the theory of equivalence of conditions (sine qua non) in understanding causation. Special rules have been developed (exceptions to the theory of equivalence) which make it possible to impute causation in the case when harm is caused by several persons (alternative causality, hypothetical causality, unintentional co-causation). In theory, the doctrine of the equivalence of conditions is supplemented by the doctrine of a «natural cause». The cause must be not only necessary for the result, but also sufficient in the context of the natural sciences. Unlike Russia and England, Germany distinguishes between causation and its «objective imputability» (beyond causation) as an independent element of actus reus. The question of the need to establish the «objective imputability» of causation in the commission of an intentional crime remains debatable; jurisprudence proceeds from the fact that causation based on sine qua non rule is sufficient to impute the result. When establishing the «objective imputability» of a causation, value judgments are used; the materiality of causation, the acceptability of risk, and the balance of interests must be proven. Unlike England, the ethical criterion (blameworthiness etc.) is not taken into account when imputing causation.

Absorptive/transmissive frequency selective surface with multiple transmission zeros for reduced transition bandwidth

An absorptive/transmissive frequency selective surface (ATFSS) with multiple transmission zeros is proposed, which consists of one lossy layer and two lossless layers separated by air space. As the key features, the slot-line loading and interlayer coupling technologies are adopted in the lossy layer and lossless layers, respectively, to introduce the infinite impedance points and four transmission zeros, thereby simultaneously achieving low insertion loss and high selectivity of the transmission band. Benefiting from the ohmic loss of the lumped resistance in the lossy layer, effective absorption can be readily implemented. A detailed qualitative analysis of the proposed structure is presented through the equivalent circuit theory, surface current, and power loss density distributions. Under normal incidence, the overall structure exhibits two discrete absorption bands over the frequency range of 6.34 to 13.40 GHz, whereas a transmission behavior is obtained from 9.34 to 11.40 GHz with a minimum insertion loss of only 0.14 dB. In particular, there are only 3.9% and 3% transition bandwidths between absorption and transmission functions. Then, a sample prototype is fabricated for demonstration, and the measured results are well consistent with the simulated one. As expected, the proposed ATFSS has the advantage of multiple transmission zeros, loss insertion loss, and narrow transition band, which is of great potential in the application of radar stealth radome.

Finite-difference modeling with topography using 3D viscoelastic parameter-modified free-surface condition

The free-surface boundary condition is a crucial aspect in the numerical modeling of (visco)elastic wave equations, especially when using a finite-difference (FD) method in the presence of surface topography. The parameter-modified method is a widely used approach to solve this problem. In this regard, the adaptive Poisson’s ratio parameter-modified method has proven to be effective in accurately simulating seismic surface waves within the FD discretization framework. Based on the equivalent medium theory, vacuum approximation, and mathematical limit, we develop a viscoelastic parameter-modified (VPM) method for the implementation of the free-surface boundary condition in the 3D viscoelastic wave equation. Our approach modifies the viscoelastic constitutive relation and density at the free surface and provides a formulation in terms of displacement and stress. We determine that our VPM method is more general than the viscoelastic stress-image method as it includes the latter as a limit case when the Poisson’s ratio equals zero. The presented free-surface method is represented implicitly within the FD grid, and we provide implementation details when simulating surface waves with topography in the standard staggered-grid FD scheme. We support our theory’s feasibility and accuracy through numerical examples.

Equivalent Circuit Models of a Bifunctional Optical Metasurface for Beam Splitting and Refractive Index Sensing

Metasurfaces have attracted extensive attention in the micro/nano-optics field depending on their significant ability to modulate optical parameters. However, the current numerical simulation technology cannot meet the demand of the design and analysis of metasurfaces efficiently due to consuming substantial calculating time and memory. Besides, they cannot illustrate the physical mechanism straightforwardly behind the optical responses. Herein, we propose and demonstrate two equivalent circuit models systematically for a bifunctional metasurface with metal–dielectric–metal structural meta-atoms based on polarization multiplexing in the visible band. In the y-polarization state, the equivalent circuit model is established to interpret the phase shift exactly with a high goodness of fit of 0.931, resulting in the beam splitting function from the anomalous reflection phenomenon. The polychromatic light splits from 34 to 69° to produce the grating-type high-saturation structural colors with a large gamut of about 170.07% of the DCI-P3 standard. In the x-polarization state, the metasurface produces the surface lattice resonance that is suitable for the refractive index sensing function due to the high sensitivity to environmental changes. The second equivalent circuit model simulates the linewidth narrowing and red-shift phenomenon with a sensitivity relative error of 7.00%. We introduce a branch with a narrow-band-pass filter and a capacitor in series into the model to mimic the characteristic of Rayleigh anomalies. Both models extend the application of equivalent circuit theory in optics further and provide a crucial approach to enhance the insights into the mechanism of metasurfaces.

Damage analysis of hybrid carbon/Glass-Epoxy pipe elbows under bending and pressure loading

Given their many advantages, composite materials have always proven their effectiveness. As in aeronautical structures where reinforcement techniques are used, their application is widened in various fields. Analyzing these composite structures or proposing new concepts for reinforcements remains an interest of several researchers. This work opts for the use of a hybrid composite of a tubular structure of an elbow attached by straight parts. The structural composite is twill. The aim of the elbow damage study is to evaluate the proposed reinforcement concept. The stiffness and damage parameters of the plies are introduced at the size of the fiber and according to the thickness per row of finite elements, hence the use of an adequate meshing technique. The linear behavior follows the equivalent stress flow theory of Von Mises. The results presented as moment-rotation curves were evaluated under design effect and bending moment mode. Depending on the loading conditions, the proposed concept of the hybrid composite showed an overcapacity of resistance where the location of the fiber qualities played the optimization of this capacity. The structure has shown even more resistance for certain locations of the folds which are reinforced in thickness. Depending on the bending moment mode applied, the results show that the damage is caused at very low deformations by ovalization of the elbow and in fiber tension.

A Study of the Aesthetics of Translation Using Functional Equivalence Theory

A Study of the Aesthetics of Translation Using Functional Equivalence Theory

A micromechanical model of multi-scale nano-reinforced composites

Nano-reinforced composites have a wide range of useful applications thanks to their exceptional all-encompassing characteristics. Understanding the micromechanical model and the reinforcing process in nano-composites is crucial for a quantitative assessment of the reinforcement impact of nano-fillers and performance optimization. The original micromechanical model for common composite materials is no longer applicable since mechanical modeling of composite materials takes into consideration variables like multi-scale, multi-phase, and multi-morphology. The multi-scale parameter equivalent modeling theory of nano-reinforced composites is examined in this work. It is suggested to use a generalized modified Halpin-Tsai micromechanical model, which may accommodate any reinforcement form, size, or orientation, after theoretical and experimental comparison and verification. A tiny sample of the nano-reinforced composite material's mechanical tensile characteristics was examined, and its microscopic.

Design and Preparation of Anti-Reflection Nanoarray Structure on the Surface of Space Solar Cell Glass Cover

Space solar cell glass covers require high radiation resistance and wide-spectrum high light transmittance. The existing research on the preparation of thin films or special optical structures on the surface of solar cells rarely involves systematic research and the precise control of the high transmittance structural parameters of specific spectral bands by glass covers. Nanoarray structures were designed and constructed on high-purity quartz glass covers, achieving high anti-reflection within the 350–1100 nm range, the high energy part of the solar spectrum on Mars, regardless of the preparation of antireflective film and its radiation resistance. First, G-Solver software package was used to establish a nanoarray structure model according to the equivalent medium theory, and the effects of structural parameters such as the grating period, grating depth, and duty cycle on the glass cover transmittance were investigated. The results show that when the grating period is 50–200 nm, the transmittance ranges from 97.8% to 99.9%. When the grating period further increases from 300 nm, the lowest point of the transmittance spectrum moves to the longwave direction, and the transmittance from 350 nm to the lowest transmittance point significantly reduces. The optimal grating depth is 500 nm for a 300 nm grating period, the transmittance at 350 nm reaches 88.91%, and the average transmittance is 98.23%. When the period is 300 nm and the depth is 500 nm, the optimal duty cycle is 0.67, the transmittance at 350 nm reaches 96.52%, and the average transmittance is 99.23%. Nanoarray structures were constructed on the glass covers with nanoimprint and plasma etching, then modified with atomic layer deposition (ALD) to adjust their depth and duty cycle. The influence rules of the grating period, depth, and duty cycle on the cover transmittance from the experimental results are basically consistent with those from the simulation calculation. The nanoarray structure increases the average transmittance within 350–1100 nm of the glass cover by an average of 2.02% and the peak transmittance by 2.66%. The research results and experimental methods of this study have application value and promotion prospects for improving the photoelectric conversion efficiency of space solar cells and ground solar cells.

Nonreciprocal absorption properties of a magneto-optical microstructure with suppressed photothermal effects

In this work, a magneto-optical microstructure of titanium (Ti)-doped ellipsoidal particles is designed, and an improved equivalent medium theory (EMT) combined with thin-film optics theory are proposed. The doped magneto-optical microstructures obtain strong broadband nonreciprocal absorption spectra in the near-infrared band, and the nonreciprocal absorption spectra remain above 0.9 at 4.5 to 5μm with nonreciprocity up to 0.53. In addition, the effects of dopant layer thickness, filling ratio and incident angle on the nonreciprocal absorption are also discussed in detail. It worth nothing that the photothermal effect of the magneto-optical microstructures are numerically studied. The optical power of the incident light affects the overall temperature rise, which results in nonreciprocal effect due to the unequal forward and reverse incident absorption spectra. It is found that the photothermal effect for our magneto-optical model caused by the plasmon effect does not produce a normal high temperature rise. The highest temperature rise is only 5.45 K for a single cycle irradiated by 50 mW of optical power, which effectively suppresses the photothermal effect, this is important for maintaining optical devices such as solar cells, optical isolators, and infrared camouflagers at optimal operating temperatures. This property provides new ideas for the design of solar cells, infrared camouflage, optical isolators, radiation-cooled films, and other applications.

Vibration behaviours of foam-filled grille composite sandwich cylindrical shells

In this study, a novel lightweight composite sandwich cylindrical shell, namely an all-composite sandwich cylindrical shell (ACSCS) with a hollow grille core (HGC) filled with polyurethane foam (PF), is designed and prepared, and its free and forced vibration behaviours are investigated for the first time. First, an analytical model of the PFHGC-ACSCSs subjected to both base excitation and single-point pulse excitation loads is developed by employing the shear deformation theory enriched by the layerwise method, virtual artificial spring technique, Rayleigh-Ritz approach, modal superposition principle, Newmark-Beta approach, and improved cross-fill equivalent theory. Furthermore, the solution procedures for the natural frequencies, mode shapes, and vibration responses in the time and frequency domains of the PFHGC-ACSCSs are defined. Convergence investigations are performed to determine the appropriate truncation numbers and stiffness values for the virtual artificial springs used in the prediction model. Both literature and experimental validations are conducted on the current model, the results of which indicate that it is reliable for predicting the concerned dynamic parameters. Finally, the effects of the critical parameters on the free and forced vibrations of the PFHGC-ACSCSs are studied. The results suggest that the vibration suppression capability could be significantly strengthened by adopting a large core-to-skin thickness ratio, high ratio of the circumferential length of the hollow grille ribs to the whole thickness, large axial and circumferential number of the hollow grille ribs, high ratio of the wall thickness to the circumferential length of the hollow grille ribs, and type of foam with a high elastic modulus. The modelling and solving techniques, preparation processes, testing methods, and conclusions of this study pave the way for the application of such shell structures.

EQUIVALENCE IN THE TRANSLATION OF METAPHORS AND IDIOMS IN KING ABDULLAH II'S POLITICAL SPEECHES

Translation is a process of converting the meaning of a certain message from one language to another language.one of the major problems encountered by translators of political speeches is translating figures of speech like metaphors and idioms and finding equivalent meaning for them. This research aims at finding the equivalent translation provided by the Royal Court translators when translating metaphors and idioms from English into Arabic in the political speeches of king Abdullah II of Jordan. In the current study, Nida (1969) theory of equivalence in translation is adapted in order to achieve the objectives of the study. Nida (1969) proposes two types of equivalence in translation, namely formal and functional/dynamic translation. This study deploys descriptive and comparative methods in dealing with the selected examples of the political speeches and discussions papers of king Abdullah II of Jordan which are published in his official website: (http://www.kingabdullah.jo) . The findings of the study revealed that translators of the royal court apply Nida (1969) theory of equivalence in translating both metaphors and idioms in the political speeches of king Abdullah II. namely, Formal and functional equivalence.

CONCEPTS OF CAUSATION IN CRIMINAL LAW: PROBLEMS, ANALYSIS AND SOLUTIONS

The article widely uses logical, inductive, deductive, systematic, logical-legal, comparative-legal research methods. In particular, it was noted that the issue of causation in the institutions of general and special parts of criminal law is very complicated and there are many problems with it. In the theory of criminal law, scientists put forward eleven theories of causation in their scientific works, and the content of the most important of them is analyzed in this article, as well as specific shortcomings of theories of causation are recognized. The scientific views and researches of scientists regarding the theories of causation in criminal law, the similarities and differences between them are described in detail. At the same time, two of the theories of causation in foreign criminal law are widely used: the theory of equivalence and adequacy, and among them: the first contains the necessary conditions ("conditio sine qua non" - "there is no condition without a necessary condition..."), and the second is adequate( exactly the same, equal, suitable) are stated to represent conditions. Also, the legal nature of eleven theories of causation in the theory of criminal law, their specific rules are comparatively analyzed, their problematic aspects are identified and sequentially described. This article focuses on eleven theories of causation in criminal law theory and provides an instrumental and comparative analysis of their intertwined provisions. Also, out of the eleven theories of causation, the theory of direct causation was found to be the most widely used. At the same time, the doctrine of criminal law and existing scientific research were analyzed, and reasonable theoretical recommendations were developed in this regard.

Flattened Gaussian focal spot with uniform phase produced by photon sieve

The equivalent pupil and the point spread function constitute the Fourier–Bessel transform relation. Based on this, we established the equivalent pupil function theory of rotating symmetric photon sieve and derived the Fourier transform of the flattened Gaussian function. The focal spot produced by this type of photon sieve exhibits a uniform intensity and phase distribution. According to the numerical results, the flattened Gaussian field distribution is consistent with the designed function. In addition, the nonuniformity in intensity and phase is approximately 1% and less than 1/170 wavelength, respectively.

Equivalent Transformation Between Axial- and Radial-Flux Permanent-Magnet Machines

In this paper, an equivalent transformation approach for permanent-magnet (PM) electrical machines using coordinate transformation theory is presented. With the proposed method, an axial-flux PM (AFPM) machine can be transformed to an equivalent radial-flux PM (RFPM) machine or vice versa. The main purpose of proposing such a transformation method is to simplify the design of AFPM for specific applications. Besides, according to the working space requirement, the shape of PM machines can be changed while maintaining magnetic performances. The proposed transformation theory is based on the basic magnetic theory and the theoretical derivation is presented in detail. The resulted transformation equations for RFPM and AFPM machines with surface-mounted PMs are friendly to engineers. Moreover, an AFPM machine is used to validate the proposed theory, both FEM and experimental results have good agreement with the results of the proposed method. With the equivalent transformation theory, engineers could design, simulate and evaluate the AFPM machines with an exist well-developed machines.

A discretization of Holst’s action for general relativity

We present a simplicial model for gravity written in terms of a discretized Lorentz connection and a discretized tetrad field. The continuum limit of its action is Holst’s action for general relativity. With the intention of using it to construct spin foam modes for quantum gravity, we write two other equivalent models written in terms of a discretized and constrained B field. The differences between our model and existing models are most likely inessential in the sense that a quantization would lead to equivalent quantum theories in the Wilsonian continuum limit. Nevertheless, we mention two features leading to possible advantages: Curvature degrees of freedom are described at the level of each 4-simplex. Our model offers a picture of bulk geometry leading to actions for matter couplings that split as a sum over 4-simplices.