Geometric Structural Model Research Articles

A fast actuated soft gripper based on shape memory alloy wires

The application of shape memory alloy (SMA) actuated soft grippers is limited by their slow recovery speed. In order to further expand their application range, as one of the solutions to address this limitation, this paper proposes a fast actuated soft gripper based on SMA wire active heat dissipation and elastic rib combination to meet the rapid actuation and recovery. The structure primarily consists of a heat dissipation module capable of winding SMA wire and a soft structure resembling a scorpion tail with embedded supper elastic SMA wire. The geometric structure model, dynamics and SMA constitutive model and finite element model of the soft gripper are established, and the lateral deformation of soft bionic scorpion tail end is analyzed through simulations and experiments. In addition, the force in designed soft gripper tip and its ability to grasp different objects are also studied through experiments. The results show that the addition of a cooling fan increased the recovery rate by about 25%, and the force in soft bionic scorpion tail end can reach about 0.12 N. The designed soft gripper can successfully grasp objects with different softness, shape, size and weight. It lays a theoretical foundation and technical support for the development of soft grippers actuated by SMA in the future.

Non-isolated high step-up DC-DC converters based on geometric structure model

Non-isolated high step-up DC-DC converters based on geometric structure model

NEUROMODULATION MODEL BASED ON MULTI-ELECTRODE COMBINED ELECTRICAL STIMULATION AND ANALYSIS OF SIGNAL CONDUCTION MECHANISM

This study aimed to analyze the diffusion of electrical stimulation signals in human tissue and provide a theoretical basis for multi-electrode combined stimulation. The standard single-layer human head model based on electromagnetic simulation was taken as the geometric structure model. The model filler was assumed to be muscle tissue, and a finite element model with muscle characteristics was established. A 20-mA DC electrical signal was input, and the propagation mechanism of the signal in the simplified brain model was calculated and analyzed through multi-physical field simulation software. The signal was mainly concentrated around the electrode; when multi-electrode combined stimulation was used, signal superposition existed at the geometric center of the model, and the signal was enhanced. Slice interception analysis demonstrated that the signal attenuation intensity was approximately 8 dB/cm in homogeneous muscle tissue. To compare the performance of the single-layer model and multi-layer model, a semi-refined digital brain model was established, and simulated signal diffusion of the two models was analyzed. Comparative analysis found that due to the uneven distribution of tissues and the high shielding property of bone, the signal was highly scattered at the bone contact, but the superposition of signals in the brain center still existed.

A Methodological Study on the Design Defending Baffles Based on Mangrove Bionics

In terms of the failure of giving considerations to both aesthetic ornamental and low-carbon function for the current disaster prevention and mitigation engineering. This study proposes the debris-disaster prevention baffles applicable to natural scenic areas which designed based on mangroves properties, to solve this problem by adopting bionic design method. The research methodology is as follows: (1) To propose a Six Elements and Ten Steps Design Method for extracting the critical bionic elements of mangrove plants that contributes to the prevention of winds and waves. (2) To construct a decision objective model based on the Analytic Hierarchy Process method (AHP). Prioritize the critical bionic design elements and build a geometric structure model. (3) To compare the disaster mitigation performance through numerical simulations, and thus select an optimal one for further studies. (4) To design the final disaster prevention product based on the above theoretical guidance, low-carbon concept, efficient protection orientation, and environment-friendly principles. This study indicates that the use of bionic design satisfies aesthetic ornamental, and low-carbon demands. The appliance of AHP avoids subjective one-sidedness in design process when considering the priority of bionic elements. The numerical simulation experiments adopted in this study aim to compare the blocking effect of different baffle models and achieve the optimization the performance in disaster prevention of traditional baffle groups. In this study, the bionic product design methodology is adopted for baffle design to solve existing aesthetic and environmental problems. The particle accumulation mass after the new baffles can be effectively reduced by 2–3 times compared to the traditional baffles. Furthermore, the new baffle is more aesthetically pleasing than the traditional ones.

Geological feature driven 3D geological modeling

In 3D geological modeling, it is generally difficult to effectively integrate geometric data and attribute data due to their different characteristics. In order to realize the integration of geological features, we propose a 3D geological modeling technology driven by geological features. We construct the geometric structure model based on 3D spatial data. By solving the geometric mapping and topological correlation of geological features, we establish the topological relationship between attribute data of various geological features and graphic elements of geometric model, and realize the effective constraints of attribute data and geometric data. Finally, we obtain a 3D geological model driven by geological features satisfying the unique topological relationship. The experimental verification is carried out through the actual engineering data located in the slope zone between Yunnan Guizhou Plateau and Guangxi basin. This technology solves the effective fusion of geometric data and attribute data, provides a comprehensive 3D model for geological comprehensive analysis and engineering application.

Advanced Estimation of Compressive Strength and Fracture Behavior in Ceramic Honeycombs by Polarimetry Measurements of Similar Epoxy Resin Honeycombs.

Finding a non-destructive characterization method for cellular ceramics’ compressive strength and fracture behavior has been a challenge for material scientists for years. However, for transparent materials, internal stresses can be determined by the non-destructive photoelastic measurements. We propose a novel approach to correlate the photoelastic stresses of polymer (epoxy resin) prototypes with the mechanical properties of ceramics (alumina). Regular and inverse epoxy honeycombs were 3D-printed via stereolithography with varying structure angles from −35° to 35°, with negative angles forming an auxetic and positive hexagonal lattice. Photoelastic measurements under mechanical loading revealed regions of excess stress, which directly corresponded to the initial fracture points of the ceramic honeycombs. These honeycombs were made by a combination of 3D printing and transfer molding from alumina. The photoelastic stress distribution was much more homogeneous for angles of a smaller magnitude, which led to highly increased compressive strengths of up to 446 ± 156 MPa at 0°. By adapting the geometric structural model from Gibson and Ashby, we showed that we could use a non-destructive technique to determine the compressive strength of alumina honeycombs from the median photoelastic stress measured on similar epoxy honeycomb structures.

Methodology of the Digital Platform of Smart Accurate Ecologically Balanced Agriculture of Adygea

The digital platform being developed is an information and mathematical model of the space of agricultural lands of Adygea, designed to solve an urgent problem of our time: automated visualization of the boundaries of spatial and temporal heterogeneity of crops and their habitat. For the first time, an automated computational model of the redistribution of agrochemical indicators in morphometrically classified quasi–homogeneous relief surfaces – geotopes in comparison with soil conditions, climatic and microclimatic fluctuations has been created. The tasks of the development include: providing automated monitoring, analysis, forecasting and optimization of crop growth conditions at the local and meso-level of natural and economic areas of the region, as well as creating an intelligent information support system for technological solutions in relation to the soil, climatic and economic conditions of a particular agricultural enterprise. At the regional and meso-level, the basic information component of the digital platform includes the hierarchy of natural and economic areas identified by methods of landscape-climatic, ecological-soil and natural-anthropogenic zoning according to the quasi-homogeneous distribution of parent rocks and natural and ecological conditions of the formation of meso-, microclimate and soils. At the local level, information is integrated with respect to the author’s information-mathematical 3D geometric structural model of the field relief surface, which provides extraction of morphometric characteristics and calculation of current lines determining the direction of movement of matter along geotopes, determination of representative points of agrochemical examination and interpolation of agrochemical analysis data in the field relief. The digital platform is being developed on the basis of the free cross-platform Quantum GIS in the form of an extension module in Python using QGIS libraries. The database of the digital platform is created on the PostgreSQL database management system. The extension module directly processes the information stored in the database to obtain consolidated information on the hierarchy of units of analysis – natural and economic area and agricultural enterprise, geotope and field.

An Electromagnetic Energy Harvester for Wireless Sensors from Power Lines: Modeling and Experiment Verification

In this study, harvesters, sensors and data acquisition cards were designed and tested to obtain data from transmission lines. In this context; numerical analyses of harvesters with two different core geometries were performed with Ansys Maxwell software. Then the voltage and power harvested by the harvesters at different line currents were measured with pre-tests in the laboratory. Analyses’ results and pre-test’s results were examined and it was determined that the geometric structure (double C) model suitable for use in overhead transmission lines with high current could be used. The field test was carried out on a distribution transformer. In the field test, the harvester mounted on the transformer supply line has charged the battery supplying the sensor circuit with sufficient power to ensure normal operation of the system. A circuit is designed to measure air temperature, humidity, pressure, altitude, air quality and transformer temperature and to transmit them to the remote distance with RF transmitter. Data received on the data collection card can be recorded at certain periods and time-based graphs of the data can be obtained by a computer interface program. The energy of this circuit is to meet the energy harvested from the electromagnetic field.

Reconstruction and optimization of the 3D geometric anatomy structure model for subject-specific human knee joint based on CT and MRI images.

BACKGROUND: Nowadays, the total knee arthroplasty (TKA) technique plays an important role in surgical treatment for patients with severe knee osteoarthritis (OA). However, there are still several key issues such as promotion of osteotomy accuracy and prosthesis matching degree that need to be addressed.OBJECTIVE: It is significant to construct an accurate three-dimensional (3D) geometric anatomy structure model of subject-specific human knee joint with major bone and soft tissue structures, which greatly contributes to obtaining personalized osteotomy guide plate and suitable size of prosthesis.METHODS: Considering different soft tissue structures, magnetic resonance imaging (MRI) scanning sequences involving two-dimensional (2D) spin echo (SE) sequence T1 weighted image (T1WI) and 3D SE sequence T2 weighted image (T2WI) fat suppression (FS) are selected. A 3D modeling methodology based on computed tomography (CT) and two sets of MRI images is proposed.RESULTS: According to the proposed methods of image segmentation and 3D model registration, a novel 3D knee joint model with high accuracy is finally constructed. Furthermore, remeshing is used to optimize the established model by adjusting the relevant parameters.CONCLUSIONS: The modeling results demonstrate that reconstruction and optimization model of 3D knee joint can clearly and accurately reflect the key characteristics, including anatomical structure and geometric morphology for each component.

Integrated Parametric Shaping of Curvilinear Steel Bar Structures of Canopy Roofs

Shaping building objects is conditioned by many interrelated factors, both architectural and structural. Modern tools for shaping structures working in the environment of Rhinoceros 3D such as Grasshopper and Karamba 3D enable algorithmic-aided shaping structures, while allowing the free flow of information between the geometric model and structural model. The aim of the research is to use these tools to test the curvilinear steel bar roofs’ structures shaped based on Catalan surfaces as well as to select the most efficient structure. Three types of roof structures were analyzed: cylindroid shape, conoid shape, and hyperbolic paraboloid shape. In order to find the most preferred structural form, evolutionary structural optimization was carried out, which allowed, among others, to determine optimal discretization of the base surface, as well as optimal positions of supporting columns. As the optimization criterion, the minimum mass of the structure was assumed. The most effective structure turned out to be a structure based on hyperbolic paraboloid supported by multi-branch columns. The use of a roof with the above structure is beneficial not only because of the low weight of the structure compared to the analyzed structures, but also due to the possibility of using flat panels on the roof.

Geometric structure model of plain woven fabric based on progressive spring-slide mechanics

The geometric structure of woven fabric affects the appearance and physical properties and can be used to predict the weavability of the fabric. An accurate description of the structure is beneficial to predict the characteristics and the appearance of the woven fabric. The purpose of the study is to build an accurate, realistic, and stable three-dimensional (3D) geometric structure model based on the mechanics for plain woven fabrics. Parameters such as the initial Young's modulus of the yarn materials, thicknesses, warp density, pre-loaded tension on the yarns, and the amount of letting-off and taking-up are considered in the model. The yarns are simplified as a series of spring-sliders that are stretched in the fabric and moved along the direction of the resultant forces step by step according to the changing forces. The yarns stop moving when all the forces reach equilibrium. The tests demonstrate that the algorithm conforms to the weaving principles. The 3D images of the geometric structure of the woven fabric at different steps are displayed by B-spline surface modeling technology. A Keyence VH600 micro-measurement system is used to measure the 3D coordinates of the real fabric accurately without destroying the fabric structure. The similarity of the real geometric structure and the calculated geometric model is evaluated by calculating the discrete Fréchet distances. The result validates that the similarity of the calculated geometric structure and the measured value is more than 90% for both the warp and weft direction.

Optimization Design of Loader Engine Stents Based on ANSYS

Seeking the best layout engine scaffold materials is always the focus of the stent design personnel stent . This object of research in this article is the engine stent of a certain loader. the geometric structure model is created by Solidworks. On this basis, finite element model is created in ANSYS. Structure of stent is optimized topologically by using variable density of topological optimization algorithm in which bracket stiffness is been as the optimization objective and reduce the materials quality is been as the state variables. And stent is modeled secondly by using gotten the most optimal topological model. The stress and deformation of the improved stent of engine increased. But weight of stents is reduced by 8.7%.

Mathematical Modeling of Grape Organs and its’ Visual

Virtual plant growth is widely applied in many fields such as agriculture, forestry research, green landscape design, education, entertainment and business etc. Plant morphological structure model can simulate the real plant dynamic development, so people may be inclined to use some methods instead of the process; therefore ,multiple produce type or equation are used for modeling of natural phenomena. This paper aims to take grape organs as an example to study 3d plant organ geometric model based on OpenGL software. In this paper, grape’s organs (fruit, flower, leaf) geometric structure model and algorithm are presented.

Methods for developing and analyzing clinically rich data for patient‐centered outcomes research: an overview

Methods for developing and analyzing clinically rich data for patient‐centered outcomes research: an overview

Three-dimensional modeling of the structure and combustion of heterogeneous condensed systems

This paper describes an approach that includes: 1) construction of a geometric structure model in the form a loose packing of spherical particles of various types and sizes in a homogeneous matrix; 2) representation of the structure as a set of cubic cells with a given set of properties. Combustion wave propagation was calculated for a model system with an interface between the solid phase and gaseous products, in which all components are capable of self-sustained combustion. The cellular automata method is used. The burning time of a cell is determined by the individual burning rate of the material filling the cell and by the current surrounding of the cell. Due to differences between local burning rates, the burning surface is nonplanar, which leads to an increase in the burning rate compared to the homogeneous relay-race model.

Single-molecule FRET measures bends and kinks in DNA

We present advances in the use of single-molecule FRET measurements with flexibly linked dyes to derive full 3D structures of DNA constructs based on absolute distances. The resolution obtained by this single-molecule approach harbours the potential to study in detail also protein- or damage-induced DNA bending. If one is to generate a geometric structural model, distances between fixed positions are needed. These are usually not experimentally accessible because of unknown fluorophore-linker mobility effects that lead to a distribution of FRET efficiencies and distances. To solve this problem, we performed studies on DNA double-helices by systematically varying donor acceptor distances from 2 to 10 nm. Analysis of dye-dye quenching and fluorescence anisotropy measurements reveal slow positional and fast orientational fluorophore dynamics, that results in an isotropic average of the FRET efficiency. We use a nonlinear conversion function based on MD simulations that allows us to include this effect in the calculation of absolute FRET distances. To obtain unique structures, we performed a quantitative statistical analysis for the conformational search in full space based on triangulation, which uses the known helical nucleic acid features. Our higher accuracy allowed the detection of sequence-dependent DNA bending by 16 degrees . For DNA with bulged adenosines, we also quantified the kink angles introduced by the insertion of 1, 3 and 5 bases to be 32 degrees +/- 6 degrees , 56 degrees +/- 4 degrees and 73 +/- 2 degrees , respectively. Moreover, the rotation angles and shifts of the helices were calculated to describe the relative orientation of the two arms in detail.

THE CLASSICAL STRUCTURE MODEL OF SINGLE PHOTON AND CLASSICAL POINT OF VIEW WITH REGARD TO WAVE-PARTICLE DUALITY OF PHOTON

The enigma of the wave-particle duality of photon has remained unimpressively explained for a century since Einstein presents the concept of the photon in 1905. This article establishes a classical geometric structure model of a single photon based on fleld matter, educes a formula for the size of a photon; assumes that there only are two kinds of photon of right hand and left hand circular polarized, and suggests the frequency ! of photon polarization rotated to be its spin frequency. It ascribes the wavelike of photon to its spin motion and the particle-like to its translation motion. From the point of photon particle instead of wave view to re-analyze Young's double-slit interference and polarizer experiments, gives reasonable mechanism. It deflnes the phase velocity and the group velocity of a photon. It gives a unifled and consistent understanding of quantum particle of light and classical electromagnetic waves fleld. Evidently, such a precisely deflned conceptual model is reasonable, objective and easy to accept for classical physicists. The puzzle (1) of the wave-particle duality of light has remained unsatisfactorily explained nearly a century since Albert Einstein flrst proposed the photon, the quantum unit of light ‡ E=~!; ~=~ ~ ·

A volumetric model for structured soils based on soil structure instability and generalized suction theories

A new compound model is developed to calculate volumetric strains of unsaturated and saturated structured soils. In this model, structured soils are regarded as the composite of undisturbed and disturbed parts, both of which are uniformly distributed. The proportion of the two parts can be calculated through the combination of a pore size distribution curve, a suggested geometric structural model, the structural instability criterion and constitutive models for remoulded soils. The overall volumetric strain increment includes three components: the elastic increment of the undisturbed part, the plastic increment of the disturbed part determined by the application of the generalized suction theory, and the structure collapse contribution which is particularly relevant to the change of void ratio from undisturbed soils to disturbed soils. The relationship between the angle-stiffness of the structural instability criterion and the degree of saturation is determined by the structural strengths revealed by compression tests of natural structured soils. The validity of this model was established by comparing calculated results with published experimental data of collapsible loess.

Oxygen activation by the noncoupled binuclear copper site in peptidylglycine alpha-hydroxylating monooxygenase. Spectroscopic definition of the resting sites and the putative CuIIM-OOH intermediate.

Spectroscopic methods, density functional calculations, and ligand field analyses are combined to define the geometric models and electronic structure descriptions of the Cu(M) and Cu(H) sites in the oxidized form of the noncoupled binuclear copper protein peptidylglycine alpha-hydroxylating monooxygenase (PHM). The Cu(M) site has a square pyramidal geometry with a long axial Cu-methionine bond and two histidines, H(2)O, and OH(-) as equatorial ligands. The Cu(H) site has a slightly D(2)(d) distorted square planar geometry with three histidines and H(2)O ligands. The structurally inequivalent Cu(M) and Cu(H) sites do not exhibit measurable differences in optical and electron paramagnetic resonance (EPR) spectra, which result from their similar ligand field transition energies and ground-state Cu covalencies. The additional axial methionine ligand interaction and associated square pyramidal distortion of the Cu(M) site have the opposite effect of the strong equatorial OH(-) donor ligand on the Cu d orbital splitting pattern relative to the Cu(H) site leading to similar ligand field transition energies for both sites. The small molecule NO(2)(-) binds in different coordination modes to the Cu(M) and Cu(H) site because of differences in their exchangeable coordination positions resulting in these Cu(II) sites being spectroscopically distinguishable. Azide binding to PHM is used as a spectroscopic and electronic structure analogue to OOH(-) binding to provide a starting point for developing a geometric and electronic structural model for the putative Cu(II)(M)-OOH intermediate in the H-atom abstraction reaction of PHM. Possible electronic structure contributions of the Cu(II)(M)-OOH intermediate to reactivity are considered by correlation to the well-studied L3Cu(II)-OOH model complex (L3 = [HB[3-tBu-5-iPrpz](3)]). The Met-S ligand of the Cu(M) site is found to contribute to the stabilization of the Cu(II)(M)-oxyl species, which would be a product of Cu(II)(M)-OOH H-atom abstraction reaction. This Met-S contribution could have a significant effect on the energetics of a H-atom abstraction reaction by the Cu(II)(M)-OOH intermediate.

Three-particle clusters and the cold-fusion problem

In the present work, we have demonstrated, by starting from rather general assumptions, that a cold-fusion research programme can be established on three physically independent approaches; one classical, another quantum-mechanical, yet another electrodynamical. Equations of motion will be applied to a specific geometric–structural model of three-particle clusters, e 1 − p( d) e 2 −. Here the heavy particle (proton, deuteron) is assumed to perform an orbital motion about the axis which joins the motionless (or almost motionless) e 1, e 2 electrons. Furthermore, we have directed our study towards metallic lattices of the palladium group to see just how the heavy particle can experience such an acrobatic dynamics. For this reason we considered the action of a time-dependent electric field combined with a constant magnetic induction (known as a Lorentz force), presumably materialized within a palladium lattice structure, to see a possible physical mechanism by which a particular three-particle cluster may pass from one stationary state to the other.