Kinds Of Shapes Research Articles

Analysis on the Stress of Hexagon Cement Block under Heavy Load and Overload Vehicles Based on Finite Element Method

The growth rates of stress in the hexagon , square and octagon cement blocks under different vehicle loads were analyzed using the finite element method (FEM). The growth rate of bottom layer stress of the hexagon is the smallest among them when vehicle loads increase. Under the 400kN loads, the growth rate of bottom layer stress of the hexagon significantly reduced as the thickness increase. When its thickness is up to 28cm,the bottom layer stress is the smallest among the three kinds of shapes. The results show that the hexagon cement block is the most suitable for overload vehicles obviously when compared to the square and octagon cement block. Therefore, hexagon cement block is the most suitable for the roads which are always under heavy and overload vehicles .

Analysis of Chip Formation Mechanism in Mill-grinding of SiCp/Al Composites

SiCp/Al composites are one kind of difficult-to-machine material. The material removal mechanism of this material is complex due to the existence of SiC reinforcement. The chip formation reflects its material removal process to a certain extent. In this article, a study of chip formation is described, and a basic physical cutting model is presented to help reveal chip formation mechanism in mill-grinding of SiCp/Al composites. The scanning electron microscope photos are used to analyze the characteristic of chip morphology. Observed results based on the materials used in the experiment indicated that there were mainly four typical chip shapes, among them schistose chips being dominant. The chip formation mechanism depended much on plastic deformation of aluminum matrix, contact position between SiC particle and diamond grit, and the removal mode of SiC particle. Under the same machining conditions, the chips generated are irregular and uneven, and include several kinds of shapes. The effect of size of SiC particles on the morphology of chips formed was also analyzed based on correlational studies and the physical cutting model for SiCp/Al composites.

CAD at the Nano Scale

This article focuses on the nanotechnology-related research work at Georgina Institute of Technology. The Georgia Institute of Technology’s Multiscale Systems Engineering Research Group is working to integrate the modeling and simulation features of today’s computer-aided design (CAD) with materials design capability. These integrated features would be available at the nano, meso, micro, and macro scales, which is called multiscale CAD. In future CAD systems, engineers will be able to zoom in to specify material morphology and distributions. Offering the capability of designing materials in CAD requires the representation of many different kinds of shapes. The multiscale CAD would also allow engineers to design better functional materials, such as state-change materials. The geometric modeling of microstructures that make up material is still in its infancy. The efficiency and controllability of complex and porous shapes are the most important research topics for the interactive modeling and design of microstructures.

Parallel generation of architecture on the GPU

AbstractIn this paper, we present a novel approach for the parallel evaluation of procedural shape grammars on the graphics processing unit (GPU). Unlike previous approaches that are either limited in the kind of shapes they allow, the amount of parallelism they can take advantage of, or both, our method supports state of the art procedural modeling including stochasticity and context‐sensitivity. To increase parallelism, we explicitly express independence in the grammar, reduce inter‐rule dependencies required for context‐sensitive evaluation, and introduce intra‐rule parallelism. Our rule scheduling scheme avoids unnecessary back and forth between CPU and GPU and reduces round trips to slow global memory by dynamically grouping rules in on‐chip shared memory. Our GPU shape grammar implementation is multiple orders of magnitude faster than the standard in CPU‐based rule evaluation, while offering equal expressive power. In comparison to the state of the art in GPU shape grammar derivation, our approach is nearly 50 times faster, while adding support for geometric context‐sensitivity.

다양한 형상비를 갖는 사각 CFRP 튜브의 굽힘 및 비틀림 특성

ABSTRACT: Fiber reinforced composite materials have outstanding specific strength and specific stiffness. So the useof composite materials increases in various kinds of industrial fields including sports goods such as bicycles.Composite materials are used to make structural parts with various kinds of shapes. Specially, rectangular compositetubes are used to make a few of composite bicycle frames, but there has been a few of research on this issue.Rectangular composite tubes are designed to have appropriate radius of curvature and endure bending and torsionalloads. In this research, nine kinds of rectangular composite tubes having aspect ratios 1:1, 1:1.5, 1:2 and radius ofcurvatures R5, R10, R15 were fabricated. The carbon fiber reinforced composite material was used to make tubeshaving same cross sectional areas. The stacking sequence of tubes is [0/90/±45]s. Experimental evaluation wasaccomplished to apply bending and torsional load to the tubes. Experimental results show that bending and torsionalcharacteristics depend on radius of curvature and aspect ratio of rectangular composite tubes.초록

Finite-Element Simulation of Different Kinds of Wafer Warpages: Spherical, Cylindrical, and Saddle

During the wafer fabrication process, wafers warp into different kinds of shapes, such as spherical, cylindrical, or saddles. These wafers may exhibit a bistable state, that is, if we apply a certain amount of pressure, they snap into another state. Though these shapes are commonly observed in the real world, we have found that it is extremely difficult to obtain these shapes in finite-element tools, such as ANSYS, because some of these states are not numerically preferred solutions. In this paper, we discuss various methodologies we have used to obtain these shapes in ANSYS. The experiments have been carried out in our fabrication lab to measure the wafer warpage at various stages of wafer fabrication. We have found that when the simulated shape matches the experiment, the warpage or maximum out of plane displacement of the wafer obtained from our simulation matches with 1% with the experimental results as well. Furthermore, ANSYS simulations show that backgrinding increases the warpage by the same amount as observed in the experiments. This paper also discusses the limitations of Stoney's formula. The final goal of this paper is to predict how warpage is going to affect the stresses in the silicon (Si) trenches in a device and if any particular trench design is going to lower the amount of wafer warpage, hence the stresses in Si trenches. Section IV shows the simulation results of stresses in the Si trenches. Since it would be computationally infeasible to model a full wafer having all the details of the trench structures, a submodeling technique has been adopted to calculate the stresses in the Si trench wall of a warped wafer. These simulation results are compared with micro-Raman spectroscopy measurements of a warped wafer.

Refining Molten Steel with Argon Blowing by Metal Nozzle Mold Bottom

Abstract: this paper describes the main characteristics of bottom blowing argon, and by comparing forging adopting the mode of bottom blowing argon process of forging with not using the technology of forging the same time and the same kind of shape of ingot production the same in the forging crack, the results of the ultrasonic flaw detection, grain size, mechanical properties, gas content in liquid steel, the influence of the mold bottom blowing argon through the comparative analysis on the influence of the inclusions, the method of die bottom blowing argon can improve the quality of steel, It is worth promoting. And the principium of die bottom blowing argon is discussed.

Influence of different temperatures on the thermal fatigue behavior and thermal stability of hot-work tool steel processed by a biomimetic couple laser technique

Abstract Three kinds of biomimetic non-smooth shapes (spot-shape, striation-shape and reticulation-shape) were fabricated on the surface of H13 hot-work tool steel by laser. We investigated the thermal fatigue behavior of biomimetic non-smooth samples with three kinds of shapes at different thermal cycle temperature. Moreover, the evolution of microstructure, as well as the variations of hardness of laser affected area and matrix were studied and compared. The results showed that biomimetic non-smooth samples had better thermal fatigue behavior compared to the untreated samples at different thermal cycle temperatures. For a given maximal temperature, the biomimetic non-smooth sample with reticulation-shape had the optimum thermal fatigue behavior, than with striation-shape which was better than that with the spot-shape. The microstructure observations indicated that at different thermal cycle temperatures the coarsening degrees of microstructures of laser affected area were different and the microstructures of laser affected area were still finer than that of the untreated samples. Although the resistance to thermal cycling softening of laser affected area was lower than that of the untreated sample, laser affected area had higher microhardness than the untreated sample at different thermal cycle temperature.

Study on Heat Distribution of Pans

During baking, rectangular pans often overcook the product and round pans can't make full use of the space of the oven. In this paper, two models are build to discuss the heat distribution and uniformity of different shapes pans. Initially build the heat uniformity Model. Through the analysis of the heat distribution and geometrical property, a formula is given to calculate the uniformity of regular polygon. In order to describe the heat uniformity of all kind of shape, the thermal distribution model is build to discuss the heat distribution of the bottom of different pans. By computer simulation, the temperature at the corners of the rectangular pan is the highest and the temperature across the outer edge of the round pan is even, which is consistent with reality.

정서장애 아동의 심리치료를 위한 동물로봇 디자인의 가이드라인

본 연구는 정서장애 아동의 심리치료를 목적으로 한 동물로봇 디자인을 위해 필요한 대상동물 선정과 가이드라인 수립을 위한 연구이다. 정서장애 아동의 경우 자신의 정서 상태를 제대로 표현하지 못하므로 기존의 치료 및 교육 방법에 제약이 많다. 1990년대 후반부터 시도되기 시작한 동물모양 로봇의 활용연구 방법은 학습장애아들에게 효과적이다. 정서장애 아동의 심리치료를 위한 동물로봇을 개발하기 위해서는 우선 어떤 동물을 대상으로 선정하느냐가 매우 중요하다. 따라서 연구의 초기단계에는 정서장애 아동을 포함한 어린이들을 대상으로 동물에 대한 선호도 조사를 통해 동물로봇의 대상을 결정하였다. 또한 어떤 형태의 동물을 가장 선호하는가에 대한 것도 선호도 조사하였다. 로봇의 외형디자인에 영향을 미치는 다양한 요소인 형태, 색상, 표정, 소리 및 움직임 등에 대한 포커스 그룹 인터뷰를 실시하여 정서장애 아동의 심리치료를 위한 동물로봇을 디자인하는데 필요한 가이드라인을 제시하였다. This research is for selection of animal and establishment of guideline which for animal robot design for the purpose of emotionally disturbed children's psychotherapy. In the case of emotionally disturbed children because of poor expression about themselves's emotional condition, there are many restriction in the existing cure and educational method. Using research method of animal shape robot which is starting to make attempt since the late 1990s is effective to learning disturbed children. For the development of animal robot for psychotherapy of emotionally disturbed children first of all which animal is selected is very important. Therefore at the early stage of research preference surveyed to children including emotionally disturbed children and decide an object of animal robot. And what kind of shape is very preferred is also preference surveyed. Through focusing group interview about shape, color, facial expression, sound, and move which have an influence on outward shape design of robot, present the guideline which is needed to animal robot design for emotionally disturbed children.

Conflation Optimized by Least Squares to Maintain Geographic Shapes

Recent technologies allowed a major growth of geographical datasets with different levels of detail, different point of views, and different specifications, but on the same geographical extent. These datasets need to be integrated in order to benefit from their diversity. Conflation is one of the solutions to provide integration. Conflation aims at combining data that represent same entities from several datasets, into a richer new dataset. This paper proposes a framework that provides a geometrical conflation that preserves the characteristic shapes of geographic data. The framework is based on least squares adjustment, inspired from least squares based generalization techniques. It does not require very precise pre-matching, which is interesting as automatic matching remains a challenging task. Several constraints are proposed to preserve different kind of shape and relations between features, while conflating data. The framework is applied to a real land use parcels conflation problem with excellent results. The least squares based conflation is evaluated, notably with comparisons with existing techniques like rubber sheeting. The paper also describes how the framework can be extended to other geometrical optimization problems.

Subdivision surfaces integrated in a CAD system

The main roadblock that has limited the usage of subdivision surfaces in computer-aided design (CAD) systems is the lack of quality and precision that a model must achieve for being suitable in the engineering and manufacturing phases of design. The second roadblock concerns the integration into the modeling workflows, that, for engineering purposes, means providing a precise and controlled way of defining and editing models possibly composed of different geometric representations. This paper documents the experience in the context of a European project whose goal was the integration of subdivision surfaces in a CAD system. To this aim, a new CAD system paradigm with an extensible geometric kernel is introduced, where any new shape description can be integrated through the two successive steps of parameterization and evaluation, and a hybrid boundary representation is used to easily model different kinds of shapes. In this way, the newly introduced geometric description automatically inherits any pre-existing CAD tools, and it can interact in a natural way with the other geometric representations supported by the CAD system.To overcome the irregular behavior of subdivision surfaces in the neighborhood of extraordinary points, we locally modify the limit surface of the subdivision scheme so as to tune the analytic properties without affecting its geometric shape. Such a correction is inspired by the polynomial blending approach in Levin (2006) [1] and Zorin (2006) [2], which we extend in some aspects and generalize to multipatch surfaces evaluable at arbitrary parameter values. Some modeling examples will demonstrate the benefits of the proposed integration, and some tests will confirm the effectiveness of the proposed local correction patching method.

Shape Optimization of the Conventional Simple Shear Specimen

Shear tests of rectangular sample are widely used by the scientific community for characterizing the material behavior due to large strains obtained. However, for some hard metals, such as the dual-phase steel DP 980, premature rupture occurs in the vicinity of the grips. Due to this fact, the shape of the shear specimen is optimized in this work with the aim of maximizing the deformation achieved in the central part of the specimen without the occurrence of rupture near the grips. As the rupture occurs at the corners of the shear specimen only the boundaries are subjected to shape optimization. A representation with cubic splines is adopted for the definition of the boundaries geometry. The material is defined by Hill’s 1948 yield criterion combined with an isotropic hardening law. Two macroscopic rupture criteria are considered and an objective function approach based on the maximization of the shear strain average value is defined. For this study, a direct search optimization method is used for minimizing the objective function. The optimized geometries obtained for the different rupture criteria and different set of design variables are compared. The use of a larger number of design variables allows to obtain optimized geometries with higher average shear strain. The best specimen geometry shape allows increasing the maximum deformation of DP 980 steel to 1.05 without occurrence of rupture. In addition, the final specimen geometries show a concave shape for the boundaries which means that this kind of shape is the best one to delay the rupture in shear specimens.

Measurement Error of the Coercivity H<sub>cj</sub> of NdFeB Permanent Magnet Caused by Air Gap

Regular rare earth permanent magnet measurement systems are only able to measure standard samples with a fixed size. But NdFeB materials are usually processed into various kinds of shapes. Bonding magnets are even often formed together with the shaft or other parts. So there will be a distinct error in conventional measurement. The magnetic field intensity distribution between two poles of the system was analyzed. Because of the existence of air gap between the magnet and the poles of the measurement system, the measurement magnetic circuit is open in this experiment. By changing the height of the magnet and air gap, the measurement error of the intrinsic coercivity Hcj of NdFeB magnets is researched under this condition.

Flexible semi‐transparent silicon (100) fabric with high‐k/metal gate devices

AbstractCan we build a flexible and transparent truly high performance computer? High‐k/metal gate stack based metal–oxide–semiconductor capacitor devices are monolithically fabricated on industry's most widely used low‐cost bulk single‐crystalline silicon (100) wafers and then released as continuous, mechanically flexible, optically semi‐transparent and high thermal budget compatible silicon fabric with devices. This is the first ever demonstration with this set of materials which allows full degree of freedom to fabricate nanoelectronics devices using state‐of‐the‐art CMOS compatible processes and then to utilize them in an unprecedented way for wide deployment over nearly any kind of shape and architecture surfaces. Electrical characterization shows uncompromising performance of post release devices. Mechanical characterization shows extra‐ordinary flexibility (minimum bending radius of 1 cm) making this generic process attractive to extend the horizon of flexible electronics for truly high performance computers.magnified imageSchematic and photograph of flexible high‐k/metal gate MOSCAPs showing high flexibility and C–V plot showing uncompromised performance.(© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Investigation of Pore Structures on Mechanical Properties of Porous Ti by 3D Finite Element Models

The pore structures on mechanical properties of porous Ti were investigated by 3D finite element models. Calculated elastic modulus and yield strength suggested that square-pore models exhibit lower modulus and higher strength compared with another two kinds of shapes (circle and hexagonal). In addition, under the condition of medium porosity (58.96%), integrated property was found in square-pore model which elastic modulus was 26.97GPa, less than 1/3 of hexagonal-pore model; while the yield strength maintained 63.82MPa, doubled the figure of circle-pore model. Thus, models with square-pore structures show potential perspective as hard tissue replacements. Investigation on anisotropy of microstructure implies that the elastic modulus was affected more intensively than the yield strength.

Teaching suggestions for the measurement of area in Elementary School. Measurement tools and measurement strategies

The present study deals with teaching the concept and measurement of area. 106 subjects of the 6th grade of Greek Elementary School measured the area of different kinds of shapes. The subjects were divided into two groups, an experimental group and a control group. In the experimental group, area evaluation was taught in a way that highlighted the conceptual characteristics of area measurement. The teaching intervention and the use of different measurement tools led to different measurement strategies. Moreover, the experimental group used more successful strategies than the control group.

유속 레이다에서의 도플러 스펙트럼 모의구현에 관한 연구

하천 및 강등의 유속 측정을 위한 레이다에서는 수면에서 반사 또는 산란되는 전자파로부터 도플러 주파수를 추정함으로서 이에 대응하는 유속 정보를 추출하게 된다. 그러나 수면으로부터 수신되는 전자파 신호들의 도플러 스펙트럼은 측정 환경 및 기상 상태에 따라 매우 다른 형태를 나타낼 수 있다. 따라서 이러한 다양한 도플러 스펙트럼들의 존재로 인하여 레이다 센서에서의 유속정보 추출 알고리즘의 정확도 및 신뢰성에 심각한 문제가 발생할 수 있다. 따라서 본 논문에서는 수면으로부터 수신되는 매우 다양한 도플러 신호 스펙트럼을 적절하게 모의 구현할 수 있는 도플러 스펙트럼 모델을 제안하였다. A current velocity measurement radar for a river or a stream estimates Doppler frequencies of return echoes to extract the corresponding surface velocity information. It is very important to maintain the reliability and accuracy of these velocity estimates for water resource management such as flooding or drought conditions. However, received Doppler spectra of water surface return echoes have very widely varying shapes according to different measurement environments and weather conditions. Therefore, serious problems may arise in maintaining the reliability and accuracy of velocity estimating algorithm in a radar sensor because of Doppler spectra which can have many different kind of shapes. Therefore, in this paper, an appropriate Doppler spectrum model is suggested to simulate many various Doppler spectra. This model can be very useful in validating the reliability and accuracy of surface velocity estimates.

Coralligenous “atolls”: Discovery of a new morphotype in the Western Mediterranean Sea

Coralligenous habitat and rhodoliths beds are very important in terms of biodiversity in the Mediterranean Sea. During an oceanographic campaign, carried out in northern Cap Corse, new coralligenous structures have been discovered. These structures, never previously identified in the Mediterranean Sea, are named “coralligenous atolls” because of their circular shape. The origin and growth dynamics of these atolls are still unknown but their form does not appear to result from hydrodynamic action and an anthropogenic origin also seems unlikely. However, this kind of shape seems rather closer to that of other circular structures (e.g. pockmarks) the origin of which is related to gaseous emissions. Further studies are needed to confirm this hypothesis through chemical analysis.

Flexible Nanocrystal-Coated Glass Fibers for High-Performance Thermoelectric Energy Harvesting

Recent efforts on the development of nanostructured thermoelectric materials from nanowires (Boukai, A. I.; et al. Nature 2008, 451, (7175), 168-171; Hochbaum, A. I.; et al. Nature 2008, 451, (7175), 163-167) and nanocrystals (Kim, W.; et al. Phys. Rev. Lett. 2006, 96, (4), 045901; Poudel, B.; et al. Science 2008, 320, (5876), 634-638; Scheele, M.; et al. Adv. Funct. Mater. 2009, 19, (21), 3476-3483; Wang, R. Y.; et al. Nano Lett. 2008, 8, (8), 2283-2288) show the comparable or superior performance to the bulk crystals possessing the same chemical compositions because of the dramatically reduced thermal conductivity due to phonon scattering at nanoscale surface and interface. Up to date, the majority of the thermoelectric devices made from these inorganic nanostructures are fabricated into rigid configuration. The explorations of truly flexible composite-based flexible thermoelectric devices (See, K. C.; et al. Nano Lett. 2010, 10, (11), 4664-4667) have thus far achieved much less progress, which in principle could significantly benefit the conversion of waste heat into electricity or the solid-state cooling by applying the devices to any kind of objects with any kind of shapes. Here we report an example using a scalable solution-phase deposition method to coat thermoelectric nanocrystals onto the surface of flexible glass fibers. Our investigation of the thermoelectric properties yields high performance comparable to the state of the art from the bulk crystals and proof-of-concept demonstration also suggests the potential of wrapping the thermoelectric fibers on the industrial pipes to improve the energy efficiency.