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To be able to produce ceramic bodies with complex shapes without interlayer delamination and warping through vat photopolymerization‐based 3D printing techniques, photosensitive ceramic slurries should be studied to prepare 3D printed green and sintered bodies. In this study, we developed dual curable acrylate–epoxide ceramic slurries for digital light processing (DLP) 3D ceramic printing. The dual curing process of the slurries is a combination of photo‐radical polymerization of acrylate and thermal cationic polymerization of cyclo‐aliphatic epoxide. The green bodies prepared by dual curing of the slurries showed higher fracture strength and better adhesion between layers and between starting particles and binder polymer in comparison to acrylate‐based green body. These advantages were due to higher crosslinking density of the binder matrix and hydrogen bonding by hydroxyl groups from epoxide ring opening. The green and sintered bodies printed with improved slurry and DLP 3D printer had flat shape without warping unlike those from acrylate‐based bodies. Moreover, the distribution of inter‐particle necking in the sintered body was uniform and the interface boundary between layers was not observed. This is because of excellent uniformity of the dual cured acrylate–epoxide polymer matrix (uniform crosslinking density in layers) in the green body and hydroxyl groups generated by epoxy ring opening. [ABSTRACT FROM AUTHOR]

In this paper, we show that any displacement of a plate is the sum of a Kirchhoff–Love displacement and two terms, one for shear and one for warping. The plate is then loaded so that bending and shear contribute the same order of magnitude to fiber rotation. [ABSTRACT FROM AUTHOR]

The present work focused on the effect of deposition path on the transient temperature distribution, heat transfer, residual deformation and residual stress of a rectangular solid deposited by electron beam freeform fabrication technology. To achieve this aim, three representative deposition paths were involved to produce rectangular solid by electron beam freeform fabrication technology. Thermal‐mechanical decoupling simulations were carried out with respect to three different deposition paths. Both of the experimental and simulation results showed that a shorter deposition track can remarkably reduce the residual stress and warping. After separating the deposition area into small segments, remarkable local bulges were formed near the conjunction lines, and overheating was prone to occur at the turning points of the conjunction lines. The present work is helpful to the selection of deposition path for additive manufacturing process. [ABSTRACT FROM AUTHOR]

Using Magnetospheric Multiscale mission (MMS) orbits in the Earth's magnetotail from 2017 to 2020, plasma conditions and the 3D spatial structure of inner‐magnetotail plasma environments (with a focus on the plasma sheet (PS)) are studied with different approaches. Threshold conditions for distinguishing the PS, PS boundary layers, and lobes are derived from the statistical properties of background plasma parameters. Our results support previous studies that employed similar methods using Cluster data. However, stronger currents are observed in both the lobes and PS, likely due to the smaller spacecraft separation (≲70 km) that can resolve thin electron‐scale currents. Threshold conditions are used together with magnetic field and electric field measurements to image the spatial structure of the PS. Results are in good agreement with a global neutral sheet model based on solar wind conditions and magnetospheric configurations. Furthermore, the Earth's dipole tilts toward the Sun around June solstice, which warps the magnetotail as much as ∼2–4 RE in Z geocentric solar magnetospheric. This warping effect is relaxed toward September equinox. Consequently, as MMS travels through the magnetotail from dawn to dusk during this period, there is an apparent dawn‐dusk asymmetry in plasma conditions between June and September. Kink‐like flapping waves and interplanetary magnetic field twisting are other mesoscale processes attributed with a few RE of flaring near the flanks. These findings reveal important insights into the mesoscale structure and dynamics of the magnetotail. Plain Language Summary: Data from 4 years of observations by NASA's MMS mission are used to statistically identify distinctive regions within the Earth's magnetospheric tail. This study reveals insights into the spatial structure of this "magnetotail" and seasonal variations attributed with changes in the Earth's magnetic field configurations, particularly those of the orientation of the Earth's dipole. Our results agree with reported findings from ESA's Cluster mission. However, certain aspects unique to MMS lead to some improved measurements and features relating to MMS orbital design. The presented results are highly beneficial to future large statistical studies with MMS data. Key Points: Inner‐magnetotail environments are statistically identified with background plasma conditions and their global 3D structure is studiedWarping effects attributed to changes in the Earth's dipole tilt angle leads to an apparent dawn‐dusk asymmetry during the summer monthsWe utilize a large volume of Magnetospheric Multiscale mission data with partial plasma moments calculated from low‐energy plasma and energetic particle instruments [ABSTRACT FROM AUTHOR]

Virtual view synthesis, which generates novel views similar to the characteristics of actually acquired images, is an essential technical component for delivering an immersive video with realistic binocular disparity and smooth motion parallax. This is typically achieved in sequence by warping the given images to the designated viewing position, blending warped images, and filling the remaining holes. When considering 6DoF use cases with huge motion, the warping method in patch unit is more preferable than other conventional methods running in pixel unit. Regarding the prior case, the quality of synthesized image is highly relevant to the means of blending. Based on such aspect, we proposed a novel blending architecture that exploits the similarity of the directions of rays and the distribution of depth values. By further employing the proposed method, results showed that more enhanced view was synthesized compared with the well‐designed synthesizers used within moving picture expert group (MPEG‐I). Moreover, we explained the GPU‐based implementation synthesizing and rendering views in the level of real time by considering the applicability for immersive video service. [ABSTRACT FROM AUTHOR]

The Saint‐Venant theory proposes an exact solution to the elastic equations for beams including warping strains due to shear force and torsion. It has been at the centre of recent developments in the field of beam theory: normal stress may at first be determined as if plane sections would remain plane but under torsion and shear force, restrain warping introduces secondary normal stress. For thin‐walled sections, the analysis of warping due to torsion is conventional and uses the concept of sectorial area. However, the problem of shear flows due to shear force is generally solved by using an energy approach in which warping only appears indirectly. By introducing a static moment function, similar to the sectorial function used for torsion, this paper proposes to take explicit account of the warping of thin‐walled sections under the effect of shear force. In the case of sections with straight walls, it is convenient to use third degree polynomials. The proposed method can easily be calculated with a spreadsheet and may be extended to any type of arch, in particular those which consist of B‐spline functions or NURBS. Different examples are analyzed. [ABSTRACT FROM AUTHOR]

The development of functional polymer parts with complex geometrical shape has been possible through additive manufacturing. In this research work, the issues such as warping, filament clogging, and layer delamination related to fused deposition modeling‐based 3D printing of nylon 6 are focused and its poor printability is improved. Nylon 6 is toughened by blending with an impact modifier, ethylene terpolymer. Complex viscosity, storage, and loss moduli of modified nylon increase significantly, which help to improve 3D printability of nylon 6. 3D printing of modified nylon is performed at optimized conditions, such as printing temperature, print speed, bed temperature, and cooling speed. Izod impact strength of 3D printed nylon 6‐based blend is observed ≈543 J m−1, which is significantly higher than the value (48 J m−1) available in literature for injection molded pristine nylon 6. Thermomechanical analysis of modified nylon shows higher coefficient of linear thermal expansion in normal direction as compared to that in flow direction, which is due to the orientation of polymer crystals during processing. The voids are observed on the cross‐sectional surface of impact fractured sample, which are responsible to produce light‐weight 3D printed specimens. [ABSTRACT FROM AUTHOR]

Anatomical study of leaf xylary vessel elements of Carthamus oxycantha under various intensities of lead (Pb) and nickel (Ni) stress (200, 400, 600, and 800 mg Pb(NO3)2, NiCl2·6H2O/kg of the soil) was conducted. The deformations caused due to metal stress were detected using point‐based image registration technique. Initially, a set of corresponding feature points called landmarks was selected for warping of two‐dimensional microscopic images of deformed/source vessel (stressed) to its normal/target (unstressed) counterpart. The results show that the target registration error is less than 3 mm using real plant image datasets. The stress caused alterations mainly in diameter, size, and shape of the cells. Average cell diameter and average wall diameter of vessels were measured with "Image J." The range of decrease in average cell diameter from 18.566 to 13.1 μm and the range of increase in average wall diameter was from 5.166 to 10.1 μm, with increase in stress factor through 200, 400, 600, and 800 mg Pb(NO3)2, NiCl2·6H2O/kg of the soil. We noted large deformation in the form of shrinkage in cell size and diminution in its diameter. The diminution in diameter and the shrinkage in cell size of vessel cells may be due to the deposition of wall materials. It can be a possible strategy to limit the water flow to overcome the rapid mobility and transportation of the excess amount of metals to safeguard the cellular components from unpleasant consequences of metallic stress. [ABSTRACT FROM AUTHOR]

All glass structure for the tower closure of the Pützerturm at TU Darmstadt More than 75 years ago, the Pützerturm closure of the clock tower of the Technische Universität Darmstadt was destroyed in the night of the fire on September 11 1944. Since then, the former clock tower presents itself as a stump at the central location of the university. Following the architectural design by Walter & Sichau Architects, the tower now has a new closure in a modern design language. The structure, designed as a fall‐protecting all‐glass construction, takes up the adaptations to the structural changes of the post‐war period and thus blends into the building ensemble. The construction, reduced to only four large‐format glass elements, each weighing about 2 t, follows the trend towards larger and larger all‐glass applications. In the present article, the construction characteristics are shown and, using this example, the object‐specific deviations from the technical building regulations and the essentially associated necessary proofs are shown, which ultimately made a project‐related construction technique permit (vBG) possible. [ABSTRACT FROM AUTHOR]

Two variational principles are proposed that describe equilibrium problems with connected nonlinear beams and solids. The principles extend the classical principle of minimum potential energy for beams and deformable bodies incorporating constraints that weakly enforce the beam kinematics at the common interface using either Lagrange multipliers or penalty terms. In contrast with existing alternatives, in the new approach, the surfaces of bodies connected to beams can deform in an energetically optimal way while globally behaving as beam cross sections. This allows, eg, warping and Poisson effects in beam/solid interfaces. Finite element implementations of the new principles are described in detail and application examples are provided that illustrate their use. [ABSTRACT FROM AUTHOR]

This paper presents a simplified co-rotational formulation for quadrilateral shell elements inheriting the merit of element-independence from the traditional co-rotational approach in literature. With the objective of application to nonlinear analysis of civil engineering structures, the authors further simplify the formulation of the geometrical stiffness using the small strain assumption, which is valid in the co-rotational approach, with the warping effects considered as eccentricities. Compared with the traditional element-independent co-rotational method, the projector is neglected both in the tangent stiffness matrix and in the internal force vector for simplicity in formulation. Meanwhile, a quadrilateral flat shell element allowing for drilling rotations is adopted and incorporated into this simplified co-rotational algorithm for geometrically nonlinear analysis involved with large displacements and large rotations. Several benchmark problems are presented to confirm the efficiency and accuracy of the proposed method for practical applications. [ABSTRACT FROM AUTHOR]

Objectives: Caudal distension of the female pelvic floor is common and results in perineal descent and a caudally curved levator hiatus (warping). Image reconstruction of the pelvic floor using currently available ultrasound techniques involves a linear approach (flat-plane reconstruction). We aimed to evaluate the feasibility, reproducibility and potential usefulness of a new three-dimensional (3D) technique capable of reconstructing a curved plane of the levator hiatus.Methods: Primiparous women were recruited to undergo a 3D/four-dimensional transperineal ultrasound examination 3-6 months after delivery. Levator ani muscle warping was evaluated on Valsalva maneuver by measuring the distance between the plane extending from the pubic rami to the anorectal angle and the plane of minimal hiatal dimensions on the coronal plane. Warping distance was used to reconstruct a curved plane of the levator hiatus using the curved OmniView volume contrast imaging (VCI) technique (C-OV). Intra- and interobserver reproducibility of the C-OV technique were assessed, as was intermethod agreement between the C-OV technique and the linear OmniView-VCI (L-OV) technique, for the measurement of levator hiatal area on Valsalva maneuver.Results: Measurement of the levator hiatal area using C-OV was feasible in all 84 women recruited. The warping distance ranged from -3.5 to 9.7 mm, confirming that the 1-2-cm slice thickness traditionally used for linear reconstruction was adequate for proper assessment of levator hiatal area in our population. C-OV showed excellent intra- and interobserver reproducibility, as well as excellent agreement with the L-OV technique for measuring levator hiatal area. No systematic difference was demonstrated in any of the reproducibility studies performed.Conclusions: 3D reconstruction of the warped levator hiatal plane is feasible and highly reproducible. In our population, reconstruction of a curved plane to correct for levator hiatal warping did not offer any benefit over the traditionally performed linear reconstruction. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a four-node quadrilateral flat shell element is proposed for geometrically nonlinear analysis based on updated Lagrangian formulation with the co-rotational kinematics concept. The flat shell element combines the membrane element with drilling degrees of freedom and the plate element with shear deformation. By means of these linearized elements, a simplified nonlinear analysis procedure allowing for warping of the flat shell element and large rotation is proposed. The tangent stiffness matrix and the internal force recovery are formulated in this paper. Several classic benchmark examples are presented to validate the accuracy and efficiency of the proposed new and more proficient element for practical engineering analysis of shell structures. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The present study outlines a sequentially integrated finite-element method (FEM)-response surface method (RSM)-genetic algorithm (GA) framework and implements this to predict the crack parameters, namely, crack location and crack depth ratio. A central composite face centered response surface design of the RSM technique is used to establish the direct relationships between the input parameters (crack location and crack depth ratio) and responses (natural frequencies) to build the response surface function (RSF). Multiple edge cracks are considered, which exist on the top flange of a thin-walled channel section cantilever beam and modeled as line spring elements. In order to obtain RSFs of the first five natural frequencies in terms of process factors such as crack position and crack depth ratio, a number of numerical experiments based on FEM are conducted by using the design-of-experiment approach. An objective function obtained as the square of the difference between RSF and experimentally measured natural frequency has been minimized using GA to find out the optimum crack parameters. Twenty-four steel channel beam specimens have been tested in the laboratory to extract the crack parameters from measured natural frequencies using the proposed approach. The results of the study indicate that the proposed approach performs remarkably, yielding crack parameters with great precision. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

One of the major problems in the signal comparison of chromatographic data is the variability of response caused by instrumental drifts and others instabilities. Measures of quality control and evaluation of conformity are inherently sensitive to shift. It is essential to be able to compare test samples to reference samples in an evolutionary analytical environment by offsetting the inevitable drift. Therefore, prior to any multivariate analysis, the alignment of analytical signals is a compulsory preprocessing step. During recent years, many researchers have taken a greater interest in the study of the alignment. The present paper is an updated review on the alignment algorithms, methods, and improvements used in chromatography. The study is dedicated to one-dimensional signals. Several of the exposed methods have common theoretical bases and can differ through their optimization methods. The main issue for the operator is to choose the appropriate method according to the type of signals to be processed. [ABSTRACT FROM AUTHOR]

SUMMARY This paper is concerned with active control of torsional vibrations in laminated rods by piezoelectric shear sensors and actuators. A piezoelectric layer can be used as a sensor by utilizing the direct piezoelectric effect, measuring either the charge on short-circuited electrodes or the voltage on open electrodes. On the other hand, the converse piezoelectric effect enables actuation by applying an electric potential difference to the electrodes of a piezoelectric layer. The sensor and actuator equations are formulated in the framework of an extended Saint-Venant torsion theory considering additional cross-sectional warping due to piezoelectric eigenstrains. A solution of the shape control problem for torsional vibrations is presented, i.e. the necessary distribution of actuation strains in order to completely compensate vibrations caused by external excitations. For the case, in which the external excitations are not known exactly, a feedback control solution is presented using one piezoelectric layer as a sensor and a second one as an actuator. For the examples of a rectangular and a circular cross-section, the theoretical results are validated by three-dimensional finite element computations, showing a very good coincidence. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

We introduce in this paper a new method for smooth foldover-free warping of images. It allows users to specify the constraints in two different ways: positional constraints to constrain the position of points in the image and gradient constraints to constrain the orientation and scaling of some parts of the image. We then show how our method is used for texture mapping with hard constraints. We start with an unconstrained planar embedding of the target mesh calculated with conventional methods. In order to obtain a mapping that satisfies the user-defined constraints, we use our warping method to align the features of the texture image with those of the unconstrained embedding. Compared to previous work, our method generates a smoother texture mapping and offers higher level of control for defining the constraints. [ABSTRACT FROM AUTHOR]

This paper describes a new integrated scheme for metamorphosis between two closed manifold genus-0 polyhedral models. Spherical parameterizations of the source and target models are created first. To control the morphing, any number of feature vertex pairs is specified and a fold-over free warping method is used to align two spherical embeddings. Our method does not create a merged meta-mesh or execute re-meshing to construct a common connectivity for morphs. Alternatively, a scheme for the progressive connectivity transformation of two spherical parameterizations is employed to generate the intermediate meshes. A novel semi-overlay with a geomorph scheme is proposed to reduce the popping effects caused by the connectivity transformation. We demonstrate several examples of aesthetically pleasing morphing sequences using the proposed scheme. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Since the dimensions for digital images are set by the acquisition system, digital image enlargement is indispensable when the dimensions that can be displayed are larger in the display system than in the acquisition system. Conventionally, this enlargement process was performed by interpolation. The digital image enlargement corresponds to a larger Nyquist frequency, but the frequency band that is expanded during the enlargement cannot be considered by the interpolation scheme, and blur is produced in the enlarged image. The parts where the image blur stands out subjectively are primarily the signals forming the image contours having the step edge shape and the details of the image consisting of mountain- and valley-shaped signals when viewed microscopically. Therefore, the proposed method moves the coordinate points interpolated to preserve the discontinuities of step edge signals and decides whether the interpolated points are the vertices of the mountain- or valley-shaped signals, and then moves the amplitudes of the interpolated points for creating these peak signals up or down. In other words, we explain an interpolation scheme involving the warping and biasing that randomly moves the coordinate points and the signal amplitudes, and implement digital image interpolation with improved resolution. Furthermore, the parameter settings for the proposed method are both objectively and subjectively evaluated. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(2): 10–21, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20095 [ABSTRACT FROM AUTHOR]

The purpose of this paper is to develop a general method, called the spline finite member element method, for predicting the effect of shearing strains in the middle surface of the walls on the buckling of thin-walled members with any cross-section because the classical theory of thin-walled members is based on the assumption of no shearing strains and is unable to reflect the shear lag phenomenon. A governing energy equation for the buckling has been derived in which the effects of torsion, warping of the member and, especially, the shearing strains in the middle surface of the wall are taken into account. The accuracy of the method is tested based on some available closed-form solutions. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]