geometric model
Recently Published Documents





Ali Ebrahimi ◽  
Kamal Mirzaie ◽  
Ali Mohamad Latif

There are several methods for categorizing images, the most of which are statistical, geometric, model-based and structural methods. In this paper, a new method for describing images based on complex network models is presented. Each image contains a number of key points that can be identified through standard edge detection algorithms. To understand each image better, we can use these points to create a graph of the image. In order to facilitate the use of graphs, generated graphs are created in the form of a complex network of small-worlds. Complex grid features such as topological and dynamic features can be used to display image-related features. After generating this information, it normalizes them and uses them as suitable features for categorizing images. For this purpose, the generated information is given to the neural network. Based on these features and the use of neural networks, comparisons between new images are performed. The results of the article show that this method has a good performance in identifying similarities and finally categorizing them.

2022 ◽  
Vol 1049 ◽  
pp. 248-254
Ivan Andrianov

The numerical method of stamp topological optimization taking into account fatigue strength is presented in the work. It is proposed to take into account the restrictions on the stress state in accordance with the curve of the dependence of the maximum stresses on the number of loading cycles in the ESO topological optimization method. An approach to the selection of the evolutionary coefficient with a step-by-step increase in the rejection coefficient is proposed when constructing an iterative scheme for the rejection of elements by the method of topological optimization. The calculation of the stamp optimal topology with a decrease in volume due to the removal and redistribution of material was carried out in the study. The new geometric model of the optimal topology stamp is based on the predicted distribution of elements with a minimum stress level. The verification calculation of the stress state of the stamp of optimal topology with an assessment of fatigue strength was carried out in the work. The numerical calculation was carried out using the finite element method in the Ansys software package. The minimized stamp volume decreased by 35% according to the calculation results. The results of the study can be further applied in the development of topological optimization methods and in the design of stamping tools of optimal topology.

Herman Szűcs

Porous materials can be found in numerous areas of life (e. g., applied science, material science), however, the simulation of the fluid flow and transport phenomena through porous media is a significant challenge nowadays. Numerical simulations can help to analyze and understand physical processes and different phenomena in the porous structure, as well as to determine certain parameters that are difficult or impossible to measure directly or can only be determined by expensive and time-consuming experiments. The basic condition for the numerical simulations is the 3D geometric model of the porous material sample, which is the input parameter of the simulation. For this reason, geometry reconstruction is highly critical for pore-scale analysis. This paper introduces a complex process for the preparation of the microstructure's geometry in connection with a coupled FEM-CFD two-way fluid-structure interaction simulation. Micro-CT has been successfully applied to reconstruct both the fluid and solid phases of the used porous material.

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 462
Hong Anh Nguyen ◽  
Van Khang Nguyen ◽  
Klaus Witrisal

Ultra-Wide Bandwidth (UWB) and mm-wave radio systems can resolve specular multipath components (SMCs) from estimated channel impulse response measurements. A geometric model can describe the delays, angles-of-arrival, and angles-of-departure of these SMCs, allowing for a prediction of these channel features. For the modeling of the amplitudes of the SMCs, a data-driven approach has been proposed recently, using Gaussian Process Regression (GPR) to map and predict the SMC amplitudes. In this paper, the applicability of the proposed multipath-resolved, GPR-based channel model is analyzed by studying features of the propagation channel from a set of channel measurements. The features analyzed include the energy capture of the modeled SMCs, the number of resolvable SMCs, and the ranging information that could be extracted from the SMCs. The second contribution of the paper concerns the potential applicability of the channel model for a multipath-resolved, single-anchor positioning system. The predicted channel knowledge is used to evaluate the measurement likelihood function at candidate positions throughout the environment. It is shown that the environmental awareness created by the multipath-resolved, GPR-based channel model yields higher robustness against position estimation outliers.

2022 ◽  
Vol 13 (3) ◽  
pp. 30
Andrew Worsley ◽  
James F. Peters

The electron magnetic moment anomaly (ae), is normally derived from the fine structure constant using an intricate method requiring over 13,500 evaluations, which is accurate to 11dp. This paper advances the derivation using the fine structure constant and a spherical geometric model for the charge of the electron to reformulate the equation for ae. This highly accurate derivation is also based on the natural log eπ, and the zero-order spherical Bessel function. This determines a value for the electron magnetic moment anomaly accurate to 13 decimal places, which gives a result which is 2 orders of magnitude greater in accuracy than the conventional derivation. Thus, this derivation supersedes the accuracy of the conventional derivation using only a single evaluation.

Alexandre Calado ◽  
Paolo Roselli ◽  
Vito Errico ◽  
Nathan Magrofuoco ◽  
Jean Vanderdonckt ◽  

Marta Quintilla Castán ◽  
Luis Agustín Hernández

With current data acquisition techniques, exhaustive documentation of patrimonial goods is generated, which allows obtaining a 3D geometric model, on which data from research from research is generated. As in other fields of architecture, the latest graphic techniques and manipulation of the image, allow a working methodology other than the current one in the patrimonial field. The information systems have been evolving towards technologies developed with open source software, the use of standards, ontologies and the structuring of information and of the 3D model itself under a semantic hierarchy. Interoperability between databases is favored and the maintenance of applications is ensured. The purpose is to support decision-making related to the model and simultaneously, serve multiple purposes such as cataloging, protection, restoration, conservation, maintenance or dissemination, among others. The research carried out for the realization of the survey of the City Council and Lonja of Alcañiz (Teruel), has the aim of expanding the historical knowledge of the buildings and delimiting its possible constructive phases, in order to obtain the geometric reality of the buildings. In this way, provide greater instruments to carry out the drafting work of the set restoration project. 

Oleksiy Vodka ◽  
Ksenia Yevgenivna Potopalska

The work is devoted the definition of the function of limiting the geometric parameters of the steam turbine blade at given external loads. For this, a geometric model of a steam turbine blade was created, consisting of a blade body, a shank, and a shroud. The variable parameters were the angle of rotation of the middle section relative to the center of mass (which varied from 87 degrees to 92 degrees), as well as the length of the blade (varied from 495 mm to 525 mm). At the next stage, a finite element mesh was created. For the constructed model, an ordered finite element mesh was created in the area of the blade. Determined the stress-strain state of the blade during the operating mode. When carrying out the static analysis, an rotation velocity of 50 Hz was used as a load, and at the point of attachment of the disk in the shank, fixed displacement of all directions were used. The equivalent von Mises stresses and displacement in the structure are obtained. The zone of maximum stresses is located at the point where the blade is attached to the shank, but they do not exceed the limits. To determine the vibration characteristics of a steam turbine blade, its modal analysis was carried out taking into account the prestressed state from the action of static loads. The first six eigen modes of a steam turbine blade are obtained under the indicated initial conditions. The eigen frequency corresponding to the first form coincides with the rotational velocity (equal to 49 Hz), and the subsequent ones correspond to the multiplicities, respectively. At the next stage, a series of calculations was carried out to determine the response surface for the given parameters. The response surface for the maximum von Mises stresses and the first 4 modes of natural vibrations are determined. On the basis of the obtained results of studies of oscillations and deformed state of the blades with varying input parameters, it is possible to obtain a constraint for solving the optimization problem.

Alexsandr Tarasov ◽  
Oksana Lytvynenko ◽  
Irina Myhaylova

Modern CFD methods for calculating combustion processes make it possible to take into account changes in temperatures, heat loads, rates of coolants, as well as further changes in fuel quality. To develop the skills of CFD design and understanding of combustion processes among future specialists in thermophysical specialties, work was carried out to simulate the burner device of a waste heat boiler. For the study, the design of the gas burner of the waste heat boiler RB-70-4.0-440, which operates as a part of the power unit at the LLC “Rubezhansky Cardboard and Container Plant” in the city of Rubezhnoe, was selected. When constructing a geometric model, the hydraulic resistance to the flow of the supply and distribution manifolds was taken into account. To simplify the calculations, the problem was carried out in a two-dimensional, axisymmetric formulation. Analyzing the computational combustion models, the Non-Premixe Combustion model was chosen, which made it possible to take into account the entry of fuel and oxidizer into the reaction zone by two different flows, as well as turbulent diffusion flame propagation. Six variants of models were investigated: the first three variants with a flame tube with a solid disc with diameters of 32, 48, 56 mm, the next three variants, had a burner with a discontinuous disk 32 mm in diameter at a distance of 6, 16, 32 mm from the flame tube. As a result of the research, the optimal shape of the burner was chosen, which corresponds to model 4, and provides a high-quality combustion process, as evidenced by the high temperature of the torch and the lowest temperature at the disk. The conducted research gives future masters the skills of modeling combustion processes in power equipment.

Sign in / Sign up

Export Citation Format

Share Document