Two-dimensional Objects Research Articles

Demixing and tetratic ordering in some binary mixtures of hard superellipses.

We examine the fluid phase behavior of binary mixtures of hard superellipses using the scaled particle theory. The superellipse is a general two-dimensional convex object that can be tuned between the elliptical and rectangular shapes continuously at a given aspect ratio. We find that the shape of the particle affects strongly the stability of isotropic, nematic, and tetratic phases in the mixture even if the side lengths of both species are fixed. While the isotropic-isotropic demixing transition can be ruled out using the scaled particle theory, the first order isotropic-nematic and the nematic-nematic demixing transition can be stabilized with strong fractionation between the components. It is observed that the demixing tendency is strongest in small rectangle-large ellipse mixtures. Interestingly, it is possible to stabilize the tetratic order at lower densities in the mixture of hard squares and rectangles where the long rectangles form a nematic phase, while the squares stay in the tetratic order.

3D printing of Fe3O4 functionalized graphene-polymer (FGP) composite microarchitectures

Magnetic graphene composite comprising graphene sheets decorated with magnetite nanoparticles (NPs) is an important material with numerous successful and potential applications in electronics, chemistry, physics, and bio-medicine. The further use of this material relies on the development of an appropriate patterning method for the production of two-dimensional (2D) and three-dimensional (3D) magnetic graphene composite objects. This study presents a simple and effective strategy to fabricate 2D and 3D micropatterns of Fe3O4 functionalized graphene-polymer (FGP) nanocomposite using extrusion-based 3D printing with a highly loaded FGP nanocomposite ink. The ink consisted of Fe3O4 nanoparticles (NPs), graphene microflakes (GMFs), and hydroxypropyl cellulose (HPC), and was stable and suitable for 3D printing of FGP objects. Various FGP 3D microarchitectures, including a grid, honeycomb, pyramid, and square, were successfully printed using the layer-by-layer (LbL) printing approach. The printed objects exhibited a conductivity of ∼580 S m−1 and magnetic property of 15.8 emu g−1. Successful demonstrations of electronic devices such as a magnet-guided car, a magnetic switch, and a 3D grid for electromagnetic interference (EMI) shielding are also described herein. This 3D printing approach was effective for the 2D and 3D patterning of functional nanocomposites and shows promise for advanced printed electronic applications.

Mental rotation of alphabet characters affects the face-sensitive N170 component.

Face-sensitive N170 component of event-related potential is sensitive to face inversion, which has been defined as the face-inversion effect. Moreover, a previous study suggested that similar to the face-inversion effect of the face-sensitive N170 affected by mental rotation of the face, object-related N170 of three-dimensional objects was also affected by the mental rotation of two-dimensional objects. The purpose of the present study was to compare the relationship between face-sensitive N170 during face perception (upright and inverted faces) and object-related N170 during character perception (normal and mirror version for alphabet characters). The results indicated that the latency of N170 for mirror version for alphabet characters was significantly longer than that for normal version for alphabet characters, and the latency of N170 for inverted faces was significantly longer than that for upright faces. Therefore, the results of the present study clearly indicate that face-sensitive N170 components are related to the mental rotation of normal and mirror version for alphabet characters. These results suggest the novel possibility that face-sensitive N170 latency can be used as a biomarker for mental rotation and that mental rotation is related to the fusiform area as a neural generator of N170 in the human brain.

Bound state in a model of electromagnetic field interacting with a material plan

In the model with Chern-Simons potential describing the coupling of electromagnetic field with a two-dimensional material, the possibility of the appearance of bound field states, vanishing at sufficiently large distances from interacting with its macro-objects, is considered. As an example of such two-dimensional material object we consider a homogeneous isotropic plane. Its interaction with electromagnetic field is described by a modified Maxwell equation with singular potential. The analysis of their solution shows that the bound state of field cannot arise without external charges and currents. In the model with currents and charges the Chern-Simons potential in the modified Maxwell equations creates bound state in the form of the electromagnetic wave propagating along the material plane with exponentially decreasing amplitude in the orthogonal to its direction.

Sparsest packing of two-dimensional objects

The concept of the sparsest packing is introduced in this paper. The sparsest packing is aimed to place the objects in the container as distant as possible. More specifically, the minimal Euclidean distance between the objects, as well as, between the objects and the boundary of the container is maximised. This new problem statement is motivated by modern clean and energy-saving technologies such as ultrasonic hardening and finishing by detonating gas mixtures. The sparsest packing of two-dimensional objects in a circular container is considered subject to balancing conditions. The objects may have regular or irregular shapes bounded by arcs and line segments. Using the phi-function technique a mathematical model is formulated and a corresponding nonlinear programming problem is stated. A solution algorithm is proposed and computational results are presented to illustrate the approach.

Addition of Illuminator Fiber Optic to Produce 3 Dimension Effects in Micrographic Observation Using Upright Microscope

Microscope is one of the tools used in practicums with high intensity. The use of a microscope adjusts to the object to be observed in order to obtain optimal micrographic results. Stereo microscopes are used to observe three-dimensional objects. Upright microscopes are used to observe two-dimensional objects. This study aims to combine the two advantages of stereo microscopy that can produce three-dimensional micrography with the advantages of an upright microscope that has a high total magnification. The method used in this study is an experimental method by adding an optical fiber illuminator in the use of an upright microscope and then applying it in various observations. The conclusion of this research is the addition of an optical fiber illuminator in observations using an upright microscope can replace the function of a stereo microscope; can produce three-dimensional effects and increase magnification in Daphnia magna micrographic observations.

Forced Convection Heat Transfer From a Particle at Small and Large Peclet Numbers

Abstract We theoretically study forced convection heat transfer from a single particle in uniform laminar flows. Asymptotic limits of small and large Peclet numbers Pe are considered. For Pe≪1 (diffusion-dominated regime) and a constant heat flux boundary condition on the surface of the particle, we derive a closed-form expression for the heat transfer coefficient that is valid for arbitrary particle shapes and Reynolds numbers, as long as the flow is incompressible. Remarkably, our formula for the average Nusselt number Nu has an identical form to the one obtained by Brenner for a uniform temperature boundary condition (Chem. Eng. Sci., vol. 18, 1963, pp. 109–122). We also present a framework for calculating the average Nu of axisymmetric and two-dimensional (2D) objects with a constant heat flux surface condition in the limits of Pe≫1 and small or moderate Reynolds numbers. Specific results are presented for the heat transfer from spheroidal particles in Stokes flow.

Dollars and Sense in the Art Market

This paper introduces a new financial metric for the art market. The metric, which we call Artistic Power Value (APV), is based on the price per unit of area (dollars per square centimeter) and is applicable to two-dimensional art objects such as paintings. This metric has several advantages from the investor’s viewpoint. It makes it easy to: (i) estimate price ranges for different artists; (ii) perform comparisons among them; (iii) follow the evolution of the artists’ creativity cycle overtime; and (iv) compare − for a single artist − paintings with different subjects or different geometric properties. This metric also facilitates the process of estimating returns and leads to a price index that satisfies the monotonicity condition. Finally, due to its transparency, the APV metric is very well suited to design derivatives-like instruments that can appeal to both, investors and speculators. Several examples using auction data demonstrate the usefulness of the APV metric.

A New Financial Metric for the Art Market

This paper introduces a new financial metric for the art market. The metric, which we call Artistic Power Value (APV), is based on the price per unit of area (dollars per square centimeter) and is applicable to two-dimensional art objects such as paintings. In addition to its intuitive appeal and ease of computation, this metric has several advantages from the investor’s viewpoint. For example, it makes it easy to: (i) estimate price ranges for different artists; (ii) perform comparisons among them; (iii) follow the evolution of the artists’ creativity cycle overtime; and (iiii) compare, for a single artist, paintings with different subjects or different geometric properties. Additionally, the APV facilitates the process of estimating total returns. Finally, due to its transparency, the APV can be used to design derivatives-like instruments that can appeal to both, investors and speculators. Several examples validate this metric and demonstrate its usefulness.

Perancangan Pembelajaran Bangun Ruang 3 Dimensi Berbasis Android

Teaching aids for learning to Build Space now still depend on the old way, namely by still using 2-Dimensional media. Teachers such as Teachers still have difficulty making visual tools to learn the material of Building 3 Dimensions. And students still find it difficult to learn and explore the material to Build Space delivered by the teaching staff, with its limitations and lack of visual tools they can only imagine what the shape of the Space Build is like. With that, the author tries to make interactive learning applications so that geometric models such as cubes, tubes, cones, pyramids and balls can foster interest in learning mathematics at elementary school level by utilizing Augmented Reality (AR) technology, which is technology that merge two-dimensional or three-dimensional virtual objects into a real environment and then project these virtual objects in real time. One of the materials in learning mathematics for fifth grade elementary school students is Build Space. If you pay attention to the average age of elementary school students in class V is at the age of 10-11 years. The author obtained the final results of the study in the form of learning to Build 3-Dimensional Space with the Virtual Button method and test results from Smartphone Xiaomi Redmi 4 devices with a minimum distance of ± 15cm and a maximum of ± 81cm. Testing the response speed <1 second, the Xiaomi Redmi 4 Smartphone shows better results than other smartphones.

О моделях диффузной границы для описания динамики объектов высшей коразмерности

Diffuse interface models are widely used to describe the evolution of multi-phase systems of various natures. Dispersed inclusions described by these models are usually three-dimensional (3D) objects characterized by phase field distribution. When employed to describe elastic fracture evolution, the dispersed phase elements are effectively two-dimensional (2D) objects. An example of the model with effectively one-dimensional (1D) dispersed inclusions is a phase field model for electric breakdown in solids. Any diffuse interface field model is defined by an appropriate free energy functional, which depends on a phase field and its derivatives. In this work we show that codimension of the dispersed inclusions significantly restricts the functional dependency of the free energy on the derivatives of the problem state variables. It is shown that to describe codimension 2 diffuse objects, the free energy of the model necessarily depends on higher order derivatives of the phase field or needs an additional smoothness of the solution, i.e., its first derivatives should be integrable with a power greater than two. Numerical experiments are presented to support our theoretical discussion.

Mental Rotation of Junior High School Students in Terms of Differences Sex

Spatial ability has been recognized as a significant human skill involving the retrieval, retention, and transformation of visual information in a special context. One type of spatial ability is the skill of performing mental rotations. Mental rotation is is the ability to rotate two or three-dimensional objects rapidly and accurately in the mind. . In other words, by way of rotating objects mentally and thereby solving problems related to space, this test includes the limit of reaction time and the rotation angle, both of which are mutually related to the degree of difficulty. The subject of this research comes from 9th grades students at junior high school in Surabaya were selected from purposive sampling. The volunteer student with high ability in mental rotation based from differences gender were selected from mathematic ability task and interviewed. The result showed that high ability male students able to visualize the result of two-dimensional wake rotation such as right triangle rotated as 45°, 90°, 180° and 360. While high-ability female students are still somewhat difficult to visualize the result of two-dimensional rotational objects such as triangle too but had difficultness when rotated as 45°.

Developed Numerical Simulation of Falling and Moving Objects in Viscous Fluids under the Action of a Reynolds Lubrication Theory and Low Reynolds Numbers

The development work focuses on the numerical simulations of free body movement in viscous fluid. The aim is to make the simulation of very slow motion of the small body in viscous fluid. We developed bodies’ immersed dynamics simulations in viscous fluid by seeking numerical solutions for appropriate field variables. We developed the methods for vertically and spherically cylindrical objects’ motions, the forces on bodies close to a plane stationary wall are computed from the velocity and pressure fields using the Stokes equation through COMSOL Multiphysics finite element software. The Navier-Stokes equation is reduced to Stokes equation there is independence of time which means object will have an effect only on the motion and the slightly compressible flow assumption is made in order to obtain smooth solution numerically. The forces on an object in slightly compressible Stokes flow have been exerted on the falling objects. The resulting forces have compared with analytical results from the Reynolds Lubrication Theory, and achieved significant results from the development method in Matlab and achieved significant numerical simulations in COMSOL. In addition, an investigation has been made to an object swimming at low Reynolds number. At low Reynolds number moving is possible when object scale is small and flow pattern is slow and sticky. We have developed a system for a thin two-dimensional (2D) worm-like object wiggle that is passing a wave along its centreline and its motion has simulated by the Ordinary Differential Equations (ODE) system and by the Arbitrary Lagrangian-Eulerian (ALE) moving mesh technology. The development method result shows that it is possible for the small object to have a motion from one position to another through small amplitudes and wavelengths in viscous fluid.

Boundary Shape Inversion of Two-Dimensional Steady-State Heat Transfer System Based on Finite Volume Method and Decentralized Fuzzy Adaptive PID Control

A shape identification scheme was developed to determine the geometric shape of the inaccessible parts of two-dimensional objects using the measured temperatures on their accessible surfaces. The finite volume method was used to calculate the measured point’s temperature in the forward problem. In the inversion problem, the decentralized fuzzy adaptive Proportion Integral Differential (PID) control (DFAC) algorithm was used to compensate for the inversion boundary by using the difference between the measurement temperature and the calculation temperature. More accurate inversion results were obtained by introducing the weighted and synthesized normal distribution. In the inversion problem, the effects of the initial guess, the number of measuring points, and the measurement error were studied. The experiment calculation and analysis showed that the methods adopted in this paper still maintain good validity and accuracy with different initial guesses and decrease the number of measuring points and the existence of measurement errors.

Two fast prototypes of web-based augmented reality enhancement for books

Purpose The purpose of this paper is to identify a light and scalable augmented reality (AR) solution to enhance library collections. Design/methodology/approach The author first did research to identify the major obstacle in creating a scalable AR solution. Next, she explored possible workaround methods and successfully developed two prototypes that make the current Web-based AR work with ISBN barcode. Findings Libraries have adopted AR technology in recent years mainly by developing mobile applications for specific education or navigation programs. Yet a straight-forward AR solution to enhance a library's collection has not been seen. One of the obstacles lies in finding a scalable and painless solution to associate special AR objects with physical books. At title level, books already have their unique identifier – the ISBN number. Unfortunately, marker-based AR technology only accept two-dimensional (2-D) objects, not the one-dimensional (1-D) EAN barcode (or ISBN barcode) used by books, as markers for technical reasons. In this paper, the author shares her development of two prototypes to make the Web-based AR work with the ISBN barcode. With the prototypes, a user can simply scan the ISBN barcode on a book to retrieve related AR content. Research limitations/implications This paper mainly researched and experimented with Web-based AR technologies in the attempt to identify a solution that is as platform-neutral as possible, and as user-friendly as possible. Practical implications The light and platform-neutral AR prototypes discussed in this paper have the benefits of minimum cost on both the development side and the experience side. A library does not need to put any additional marker on any book to implement the AR. A user does not need to install any additional applications in his/her smartphone to experience the AR. The prototypes show a promising future where physical collections inside libraries can become more interactive and attractive by blurring the line of reality and virtuality. Social implications The paper can help initiate the discussion on applying Web-based AR technologies to library collections.

Scaling relationships between acoustic and electromagnetic scattering by an infinite cylinder

The conversion relationships, including the scaling of frequencies and sizes, between the scattering of a uniform plane electromagnetic wave by a dielectric cylinder and the scattering of a uniform plane acoustic wave by a non-shear-stress cylinder are studied. Owing to the dependence of electromagnetic scattering on polarization, especially for dielectric materials, a simulation method using two acoustic materials is proposed for cases with complex polarization, such as circular polarization. The scaling relationships are verified by simulation. This approach proves to be an effective supplement to the indirect method of measuring electromagnetic scattering by acoustic scattering. A preliminary study of scattering by three-dimensional objects is also performed for the simplest case of spheres. Although the results are not as good as those for two-dimensional objects, the errors after processing are sufficiently small for these results to be accepted as estimates.

HGAN

In this article, we propose a novel method to address the two-dimensional (2D) image-based 3D object retrieval problem. First, we extract a set of virtual views to represent each 3D object. Then, a soft-attention model is utilized to find the weight of each view to select one characteristic view for each 3D object. Second, we propose a novel Holistic Generative Adversarial Network (HGAN) to solve the cross-domain feature representation problem and make the feature space of virtual characteristic view more inclined to the feature space of the real picture. This will effectively mitigate the distribution discrepancies across the 2D image domains and 3D object domains. Finally, we utilize the generative model of the HGAN to obtain the “virtual real image” of each 3D object and make the characteristic view of the 3D object and real picture possess the same feature space for retrieval. To demonstrate the performance of our approach, We established a new dataset that includes pairs of 2D images and 3D objects, where the 3D objects are based on the ModelNet40 dataset. The experimental results demonstrate the superiority of our proposed method over the state-of-the-art methods.

Induced drag in two dimensions in ideal fluids

In this paper we suggest a model for how a significant part of the drag forces on two-dimensional objects can be derived using the circulation that is naturally maintained around the objects. We assume incompressible and inviscid potential flow and that the circulation is already generated. The resulting velocity field complements the one that is known to generate Prandtl’s induced drag in three dimensions. We demonstrate how fluid particles in a velocity field are attracted towards an object, and that this, due to conservation of momentum, results not only in lift, but also in drag forces. The magnitude of a disturbance velocity can be derived from the circulation of bound and shed vortices accompanying the object and parameters taken from the von Kármán vortex street description. Another part of the drag is generated by vortices that emerge behind blunt bodies when fluid particles do not follow the surface of the objects. We obtain a mathematical description of the resistance of several types of blunt bodies and rotating cylinders. The model involves no parameters that are derived from empirical data. Still, this inviscid approach corresponds well with experimental data in viscous flow and is close to a mathematical empirical description of rotating cylinders by W. G. Bickley.

Augmented Reality-Based Instructional Media for Electrical Power Protection Learning

Augmented reality is a technology that combines two-dimensional and/or three-dimensional virtual objects into a real three-dimensional environment and projects those virtual objects in real time. This study was aimed at discussing (1) the development of an instructional media for power system protection learning, especially the fuse cut out, using augmented reality, (2) the appropriateness of the developed media as evaluated by both material and media experts, and (3) the users’ responses toward the developed media. This media was developed using the waterfall model proposed by Pressman, consisting of four main stages: analyzing, designing, coding, and testing. The performance test proved that this media functioned properly (100%). This media was categorized as “highly appropriate” in terms of the materials presented as evaluated by the material experts with a mean score of 96.5 out of 112. Meanwhile, the media was “appropriate” as evaluated by the media experts with a mean score of 68 out of 84. For the end users of this media, 75% of them perceived this media as “highly appropriate”, while the rest considered it as “appropriate”.

Optimal one-dimensional structures for the principal eigenvalue of two-dimensional domains

A shape optimization problem arising from the optimal reinforcement of a membrane by means of one-dimensional stiffeners or from the fastest cooling of a two-dimensional object by means of “conducting wires” is considered. The criterion we consider is the maximization of the first eigenvalue and the admissible classes of choices are the one of one-dimensional sets with prescribed total length, or the one where the constraint of being connected (or with an a priori bounded number of connected components) is added. The corresponding relaxed problems and the related existence results are described.