Bodies Of Different Shapes Research Articles

MATHEMATICAL MODELING AND EXPERIMENTAL STUDY OF THE PROCESS OF ELECTROMAGNETIC-CONVECTIVE DRYING OF PLANT MATERIALS

The work on electromagnetic drying with heat supply to the dried material using high and ultrahigh frequency currents and in the infrared frequency range - with oscillating energy supply is analyzed. (Research purpose) The research purpose is in analytical mathematical describing the oscillating electromagnetic-convective drying of materials, as well as the method of drying seeds of vegetable crops, non-traditional and rare plants that improve their sowing qualities. (Materials and methods) Obtained solutions to the problems of heating the material using the analytical method of integral transformations. Experimental studies were carried out on oscillating infrared drying on seeds of vegetable crops, non-traditional and rare plants. (Results and discussion) The combined electromagnetic-convective drying of materials was considered, in which the energy for drying is supplied using an electromagnetic field and convectively using a preheated drying agent. Mathematical models describing the digitizing heating of bodies of different shapes (unlimited plate, infinite cylinder, ball) under conditions of convective drying were analyzed. The results of numerical modeling of the process of oscillating infrared drying of onion seeds in a fluidized bed are presented, which show that the necessary technological drying mode can be found by numerical modeling based on the obtained models. (Conclusions) Presented mathematical models that allow numerical modeling of electromagnetic-convective drying and finding the required hardware and technological design of the process. It was determined that oscillating infrared drying of seeds of vegetable crops, non-traditional and rare plants when the seed temperature fluctuates from tmin = 34 degrees Celsius to tmax = 40 degrees Celsius causes seed stimulation, which manifests itself in an increase in germination energy and germination. It was found that the germination of vegetable seeds increases by 11-24 percent (from control), and the germination energy - by 12-73 percent, seeds of non-traditional and rare plants, respectively, by 13-24 percent and 14-82 percent.

Automatic Labeling Method of Geological Codes Based on Multi-factor Optimization

Automatic labeling of geological codes is an important part of automatic mapping of geological maps. A multi-factor optimization based automatic labeling method is proposed to address the issue of existing polygon feature label placement methods being unable to achieve multi-position placement in geological codes. Firstly, classify geological bodies based on whether they can accommodate geological codes within the area; Subsequently, sufficient candidate positions are obtained for the geological body and a candidate position evaluation method that integrates multiple factors is proposed; Finally, based on the candidate position evaluation method, sorting and particle swarm optimization algorithms are used to achieve single position labeling and multi-position labeling. The simulation experiment compares it with existing polygon feature placement methods from the perspectives of coverage, shape, and method. The method proposed in this paper can automatically placement non-conflicting geological codes for geological bodies of different shapes and areas, and has better performance than existing methods in complex geological bodies.

Numerical Analysis of Flow Over Bluff Bodies of Different Shapes

Numerical Analysis of Flow Over Bluff Bodies of Different Shapes

Mean time of diffusion- and reaction-limited loading and unloading

Direct determination of mean diffusion times from the Laplace transform of the spatial average of the diffusing species for p=0 offers the advantage of yielding closed-form expressions rather than sum-type ones obtained otherwise from the time-dependent solution. This is made use of in the present work to determine the mean time of diffusion- and reaction-limited loading and unloading a species into or out of bodies of different shape (plate, cylinder, sphere) for the important type of boundary condition of fixed concentration in the surrounding. This approach particularly pays off for more complex cases when the calculation from the inverse of the Laplace transform becomes more and more laborious. As an example of such type, concomitant trapping and untrapping of the diffusing species within the object during unloading is considered. The obtained solutions are quantitatively discussed with examples from literature. The present concept of the mean time of loading or unloading is compared with other time constants, e.g., mean action time or time lag.

A new scaling for the flow instability past symmetric bluff bodies

A scaling law to predict the onset of the primary Hopf instability in the steady flow past two-dimensional symmetric bluff bodies is proposed. It uses a measure of the spatial extent of the separation bubble as the length scale and the largest reverse-flow speed within it as the velocity scale. The ensuing Reynolds number, evaluated at the onset of the primary Hopf bifurcation, collapses quite nicely for bodies of different shape and aspect ratio even when a small angle of attack perturbs the symmetry; its relative variation is one order of magnitude smaller than that of the usual Reynolds number defined with the free-stream velocity and the cross-stream body size. With the new scaling, it can be roughly assessed whether the steady flow past a two-dimensional bluff body is absolutely and globally unstable to two-dimensional perturbations without a computationally expensive stability analysis: only the inspection of the base flow is required. More importantly, the scaling provides an insight into the flow mechanism that produces the instability.

Planetesimals on Eccentric Orbits Erode Rapidly

Abstract We investigate the possibility of erosion of planetesimals in a protoplanetary disk. We use theory and direct numerical simulations (lattice Boltzmann method) to calculate the erosion of large—much larger than the mean-free path of gas molecules—bodies of different shapes in flows. We find that erosion follows a universal power law in time, at intermediate times, independent of the Reynolds number of the flow and the initial shape of the body. Consequently, we estimate that planetesimals in eccentric orbits, of even very small eccentricity, rapidly (in about 100 yr) erodes away if the semimajor axis of their orbit lies in the inner disk—less than about 10 au. Even planetesimals in circular orbits erode away in approximately 10,000 yr if the semimajor axis of their orbits are ⪅0.6 au.

On mesh adaptation for supercomputer simulation of flows around solid bodies defined by immersed boundary method

Abstract The paper presents the numerical method to simulate viscous compressible flows near moving bodies of different shapes on unstructured meshes. The boundary method is used to define the moving bodies. It allows us to operate in simply connected computational domains, while the solid objects are modeled by adding extra source terms in the governing gasdynamic equations. To improve the quality of mesh resolution near the boundary of immersed body, a specific method of dynamic mesh adaptation is developed. This method uses the variational approach. It moves the mesh nodes without changing the mesh topology. The body shape might be described analytically, however, in the general case, the level-set interpolation grid is used for this purpose. It serves as a carrier of the distance function values and its gradients. In the present work the combination of the described techniques is verified on the two-dimensional case which simulates the flow induced by the forced oscillation of a cylinder.

Fingertip-Based Feature Analysis for the Push and Stroke Manipulation of Elastic Objects.

In this study, to quantitatively understand finger operations used to manipulate elastic objects, we explore robust fingertip-based feature descriptors that are invariant to operator, finger position, and target object. To measure the tactile information generated when an object is directly touched by a fingertip, we used a wearable system that enables the simultaneous measurement of fingertip position and strain without inhibiting the operator's sense of touch. This paper focuses on the quantitative classification of the push and stroke operations of a single finger, and conducted user experiments to obtain time-series fingertip position and strain from 10 subjects touching nine types of elastic objects. The recognition rate was investigated by binary classification using a support vector machine and cross validation. The results show that the two-dimensional features obtained from fingertip position and strain within a 0.9-s time frame can stably recognize push and stroke operations on elastic bodies of different shapes, stiffnesses, and thicknesses at a higher recognition rate.

Single-phase and two-phase flow properties of mesaverde tight sandstone formation; random-network modeling approach

3D random networks are constructed in order to represent the tight Mesaverde formation which is located in north Wyoming, USA. The porous-space is represented by pore bodies of different shapes and sizes which are connected to each other by pore throats of varying length and diameter. Pore bodies are randomly distributed in space and their connectivity varies based on the connectivity number distribution which is used in order to generate the network. Network representations are then validated using publicly available mercury porosimetry experiments.The network modeling software solves the fundamental equations of two-phase immiscible flow incorporating wettability and contact angle variability. Quasi-static displacement is assumed. Single phase macroscopic properties (porosity, permeability) are calculated and whenever possible are compared to experimental data. Using this information drainage and imbibition capillary pressure, and relative permeability curves are predicted and (whenever possible) compared to experimental data.The calculated information is grouped and compared to available literature information on typical behavior of tight formations. Capillary pressure curve for primary drainage process is predicted and compared to experimental mercury porosimetry in order to validate the virtual porous media by history matching. Relative permeability curves are also calculated and presented.

Numerical modeling of percolating flow path in a caprock formation during aquifer pressurization and its implication for CO2 sequestration

Spatial distribution of sand bodies in caprock is important to its sealing potential in the evaluation of a potential waste disposal site. A numerical investigation was conducted to investigate the roles of sand bodies in caprock integrity, and a new leaking mechanism associated with the embedded sand bodies has been identified for the first time. This numerical model is characterized by a low proportion of sand bodies in caprock formation and stochastic permeability assignments to the shale facies with a consideration of stress-sensitive permeability. The research revealed that sand bodies in caprock, even initially unconnected due to their low concentration, represent the foundation for creating a percolating flow path if certain conditions are met. These conditions include a relatively high pore pressure gradient across the caprock, which may occur during fluid injection and a favorable geometric configuration of these sand bodies. Sand bodies of different shapes play different roles in forming a percolating flow path. Sand bars/dykes can lead pore pressure front to cover a considerable vertical thickness quickly, while thin sand sheets tend to transfer the pore pressure front across a large horizontal range and thus increase the possibility of involving other local sand bodies in the evolution of percolating flow paths. On the other hand, the presence of percolating flow path in caprock can limit the pore pressure increase in the aquifer formation during fluid injection. The more active the flow paths, the less increase the pore pressure that occurs in the aquifer. Stress-dependent permeability can facilitate the formation of percolating flow path, but evaluating how much impact it may have remains a question for future research. The modeling results indicate that the underlying geologically based discrete structure of permeable domains, even when masked by a low-permeable rock matrix, exerts a significant influence on the location and magnitude of fluid flow within the system during fluid injection.

The Potential Field of Carbon Bodies as a Basis for Sorption Properties of Barrier Gas Systems

A modification of the Lennard–Jones potential allowed us, via integration over the volume of the bodies of different shapes, to determine the integral action (potential energy barrier) generated by the distributed force centers. The body generating the potential barrier was a carbon plate and the test particles overcoming this barrier were atoms or molecules of a number of gases (hydrogen, helium and methane). When considering the transit of particles (gas atoms or molecules) over this barrier, use was made of the energy barrier wave theory and the potential of a continuous body was used as a barrier. In so doing, the Schrodinger equation was integrated numerically for the molecular density. This integration yielded the expected wave pattern of the process of transit and reflection of the molecules, so a phase averaging procedure had to be applied. By varying the parameters of the layer containing force centers – field sources, the dimensions and density of the carbon plate possessing high selectivity towards separation of gas mixture containing helium, hydrogen and methane were determined. The data obtained provide an interpretation of the sorption properties of barrier carbon systems capable of filtering or separating gases.

From body measurements to body shape perception: an intelligent tool for garment design

This paper presents a model characterising the relation between emotional descriptive keywords describing human body shapes and concrete body measurements. Three procedures have been proposed for building this model. In the first procedure, the experts generate a list of emotional descriptors describing human body shapes and then evaluate a set of virtual human bodies of different shapes using these descriptors. Next, two algorithms of decision tree (CART and fuzzy-ID3) have been applied for modelling the relation between each emotional descriptor and the ratios of relevant body measurements. In the second procedure, the experts evaluate the relationship between these concrete emotional descriptors and a number of abstract fashion themes such as ‘sporty’ and ‘attractive’ without taking into account any specific human body shape. This conceptual relationship given by different experts is modelled using a fuzzy cognitive map. In the third procedure, the two previous models are combined using the fuzzy relation operations. Using this combined model, garment designers can quickly identify personalised and variable body shapes, expressed by a set of concrete and abstract keywords, from human body measurements. These keywords will be further integrated into an expert knowledge base of garment design for developing personalised new products.

Optimal distribution of imperfection in conductive constructal designs of arbitrary configurations

In the last decade, different conductive networks for cooling heat generating bodies have been proposed, analyzed, and optimized. Links of a highly conductive material collect the heat generated in an area and conduct it to a heat sink. The important design point is how to dedicate the limited and expensive high conductivity material to each link. Although optimizations have been performed for heat generating bodies of different shapes separately, the lack of a general method is quite obvious in the literature. Therefore, an analytical general solution for optimal distribution of highly conductive material in networks of arbitrary configuration is developed in the present article. The proposed method gives the optimum thickness of each link with a simple expression, which only depends on the geometry of heat generating bodies. Moreover, it is mathematically proved that total thermal resistance of the optimal links is a function of Bejan's parameter k̂φ and a purely geometrical function. This achievement greatly simplifies the design and optimization of any conductive cooling network. Results of the present simple formulation for configurations of various geometries are completely consistent with the available analytical and numerical solutions.

DRAPE

We describe a complete system for animating realistic clothing on synthetic bodies of any shape and pose without manual intervention. The key component of the method is a model of clothing called DRAPE (DRessing Any PErson) that is learned from a physics-based simulation of clothing on bodies of different shapes and poses. The DRAPE model has the desirable property of "factoring" clothing deformations due to body shape from those due to pose variation. This factorization provides an approximation to the physical clothing deformation and greatly simplifies clothing synthesis. Given a parameterized model of the human body with known shape and pose parameters, we describe an algorithm that dresses the body with a garment that is customized to fit and possesses realistic wrinkles. DRAPE can be used to dress static bodies or animated sequences with a learned model of the cloth dynamics. Since the method is fully automated, it is appropriate for dressing large numbers of virtual characters of varying shape. The method is significantly more efficient than physical simulation.

Visual hull method for tomographic PIV measurement of flow around moving objects

Tomographic particle image velocimetry (PIV) is a recently developed method to measure three components of velocity within a volumetric space. We present a visual hull technique that automates identification and masking of discrete objects within the measurement volume, and we apply existing tomographic PIV reconstruction software to measure the velocity surrounding the objects. The technique is demonstrated by considering flow around falling bodies of different shape with Reynolds number ~1,000. Acquired image sets are processed using separate routines to reconstruct both the volumetric mask around the object and the surrounding tracer particles. After particle reconstruction, the reconstructed object mask is used to remove any ghost particles that otherwise appear within the object volume. Velocity vectors corresponding with fluid motion can then be determined up to the boundary of the visual hull without being contaminated or affected by the neighboring object velocity. Although the visual hull method is not meant for precise tracking of objects, the reconstructed object volumes nevertheless can be used to estimate the object location and orientation at each time step.

Penetration of Electric Field into Hollow Dielectric Bodies

Electrostatic field distribution inside dielectric hollow bodies of different shapes was determined using Charge Simulation Method. The obtained results were compared with a commercial software results. Determination of the optimal positions of fictitious charges in the Charge Simulation Method was also considered. The results are presented graphically and in tables. Ill. 13, bibl. 10, tabl. 5 (in English; abstracts in English and Lithuanian).http://dx.doi.org/10.5755/j01.eee.116.10.872

Using Physical Models to Study the Gliding Performance of Extinct Animals

Aerodynamic studies using physical models of fossil organisms can provide quantitative information about how performance of defined activities, such as gliding, depends on specific morphological features. Such analyses allow us to rule out hypotheses about the function of extinct organisms that are not physically plausible and to determine if and how specific morphological features and postures affect performance. The purpose of this article is to provide a practical guide for the design of dynamically scaled physical models to study the gliding of extinct animals using examples from our research on the theropod dinosaur, †Microraptor gui, which had flight feathers on its hind limbs as well as on its forelimbs. Analysis of the aerodynamics of †M. gui can shed light on the design of gliders with large surfaces posterior to the center of mass and provide functional information to evolutionary biologists trying to unravel the origins of flight in the dinosaurian ancestors and sister groups to birds. Measurements of lift, drag, side force, and moments in pitch, roll, and yaw on models in a wind tunnel can be used to calculate indices of gliding and parachuting performance, aerodynamic static stability, and control effectiveness in maneuvering. These indices permit the aerodynamic performance of bodies of different shape, size, stiffness, texture, and posture to be compared and thus can provide insights about the design of gliders, both biological and man-made. Our measurements of maximum lift-to-drag ratios of 2.5-3.1 for physical models of †M. gui suggest that its gliding performance was similar to that of flying squirrels and that the various leg postures that might have been used by †M. gui make little difference to that aspect of aerodynamic performance. We found that body orientation relative to the movement of air past the animal determines whether it is difficult or easy to maneuver.

Laminar Natural Convection Heat Transfer From Isothermal Cylinders With Active Ends

Calculation of free convection heat transfer from isothermal bodies of different shapes is of fundamental importance in science and engineering. In the present study, a new analytical model is developed to calculate laminar natural convection heat transfer from finite isothermal cylinders of arbitrary aspect ratio and orientation (vertical, horizontal, and inclined) with active ends in fluids of any Prandtl number. This method is based on the new concept of Dynamic Body Gravity Function. Also, a new dimensionless parameter called Body Fluid Function is introduced and applied in this method. Results of this dynamic model are presented for six different circular cylinders and compared with the available experimental data. Excellent agreement is found between the developed model and experimental results in a wide range of Rayleigh number for all cylinders discussed. This shows that the present method is a powerful tool for modeling laminar natural convection from isothermal bodies.

МетоД вИзуалИзацИИ течениЯ газОвОгО потокА нА поверхностИ теЛ различноЙ формЫ

The method for the gas flow visualizing on the surface of bodies of different shapes was tested. The proposed method provides a fixed flow pattern at an arbitrary location of the investigated models in space. Obtained flow patterns are in good accordance with the earlier studies

Calculation of radiation in gas around a descent space vehicle

The problem of numerical modeling of the effect of radiation processes on gas dynamic parameters around a descent space vehicle in the Earth’s atmosphere is studied. A relatively new approach is suggested of direct modeling of radiation processes oriented to the use of high performance multiprocessor computer systems. The physical model of radiation transfer is described by a diffusion approach with a discretization of radiation and absorption spectra and a set of quasigasdynamic equations. The computations were carried out on both triangular and hybrid locally refined grids. The gas-flow modeling results taking into account radiation processes are represented for bodies of different shapes.