Journal articles on the topic 'Material appearance modeling'
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1
Tominaga, Shoji, and Giuseppe Claudio Guarnera. "Measuring, Modeling, and Reproducing Material Appearance from Specular Profile." Color and Imaging Conference 2019, no. 1 (October 21, 2019): 279–83. http://dx.doi.org/10.2352/issn.2169-2629.2019.27.50.
Abstract:
A method is proposed for measuring, modeling, and reproducing material appearance from the specular profile representing reflectance distribution around a specular highlight. Our method is aimed at opaque materials with a highly glossy surface like plastic, ceramic, and metals. Hence, the material surface is assumed to be not a perfect mirror, but a surface with some roughness. We do not use a gonio-spectrophometer nor an image-based measurement setup. Instead, we make use of a gloss meter with a function to measure the specular profile, containing for glossy materials appearance such as roughness, sharpness, and intensity. The surface reflection is represented as a linear sum of diffuse and specular reflection components, the latter described by the Cook-Torrance model. The specular function represents the glossy surface appearance by a small number of control parameters. Mitsuba rendering system is utilized to perform the rendering algorithms. Finally, the feasibility of the proposed method is examined using different materials.
2
Baranoski, Gladimir. "Hyperspectral Modeling of Material Appearance: General Framework, Challenges and Prospects." Revista de Informática Teórica e Aplicada 22, no. 2 (November 25, 2015): 203. http://dx.doi.org/10.22456/2175-2745.56437.
Abstract:
The main purpose of this tutorial is to address theoretical and practical issues involved in the development of predictive material appearancemodels for interdisciplinary applications within and outside the visible spectral domain. We examine the specific constraints and pitfalls found in each of the key stages of the model development framework, namely data collection, design and evaluation, and discuss alternatives to enhance the effectiveness of the entire process. Although predictive material appearance models developed by computer graphics researchers are usually aimed at realistic image synthesis applications, they also provide valuable support for a myriad of advanced investigations in related areas, such as computer vision, image processing and pattern recognition, which rely on the accurate analysis and interpretation of material appearance attributes in the hyperspectral domain. In fact, their scope of contributions goes beyond the realm of traditional computer science applications. For example, predictive light transport simulations, which are essential for the development of these models, are also regularly beingused by physical and life science researchers to understand andpredict material appearance changes prompted by mechanisms which cannot be fully studied using standard ``wet'' experimental procedures.For completeness, this tutorial also provides an overview of such synergistic research efforts and in silico investigations, which are illustrated by case studies involving the use of hyperspectral material appearance models.
3
Hu, Yiwei, Chengan He, Valentin Deschaintre, Julie Dorsey, and Holly Rushmeier. "An Inverse Procedural Modeling Pipeline for SVBRDF Maps." ACM Transactions on Graphics 41, no. 2 (April 30, 2022): 1–17. http://dx.doi.org/10.1145/3502431.
Abstract:
Procedural modeling is now the de facto standard of material modeling in industry. Procedural models can be edited and are easily extended, unlike pixel-based representations of captured materials. In this article, we present a semi-automatic pipeline for general material proceduralization. Given Spatially Varying Bidirectional Reflectance Distribution Functions (SVBRDFs) represented as sets of pixel maps, our pipeline decomposes them into a tree of sub-materials whose spatial distributions are encoded by their associated mask maps. This semi-automatic decomposition of material maps progresses hierarchically, driven by our new spectrum-aware material matting and instance-based decomposition methods. Each decomposed sub-material is proceduralized by a novel multi-layer noise model to capture local variations at different scales. Spatial distributions of these sub-materials are modeled either by a by-example inverse synthesis method recovering Point Process Texture Basis Functions (PPTBF) [ 30 ] or via random sampling. To reconstruct procedural material maps, we propose a differentiable rendering-based optimization that recomposes all generated procedures together to maximize the similarity between our procedural models and the input material pixel maps. We evaluate our pipeline on a variety of synthetic and real materials. We demonstrate our method’s capacity to process a wide range of material types, eliminating the need for artist designed material graphs required in previous work [ 38 , 53 ]. As fully procedural models, our results expand to arbitrary resolution and enable high-level user control of appearance.
4
Liao, Chenxi, Masataka Sawayama, and Bei Xiao. "Unsupervised learning reveals interpretable latent representations for translucency perception." PLOS Computational Biology 19, no. 2 (February 8, 2023): e1010878. http://dx.doi.org/10.1371/journal.pcbi.1010878.
Abstract:
Humans constantly assess the appearance of materials to plan actions, such as stepping on icy roads without slipping. Visual inference of materials is important but challenging because a given material can appear dramatically different in various scenes. This problem especially stands out for translucent materials, whose appearance strongly depends on lighting, geometry, and viewpoint. Despite this, humans can still distinguish between different materials, and it remains unsolved how to systematically discover visual features pertinent to material inference from natural images. Here, we develop an unsupervised style-based image generation model to identify perceptually relevant dimensions for translucent material appearances from photographs. We find our model, with its layer-wise latent representation, can synthesize images of diverse and realistic materials. Importantly, without supervision, human-understandable scene attributes, including the object’s shape, material, and body color, spontaneously emerge in the model’s layer-wise latent space in a scale-specific manner. By embedding an image into the learned latent space, we can manipulate specific layers’ latent code to modify the appearance of the object in the image. Specifically, we find that manipulation on the early-layers (coarse spatial scale) transforms the object’s shape, while manipulation on the later-layers (fine spatial scale) modifies its body color. The middle-layers of the latent space selectively encode translucency features and manipulation of such layers coherently modifies the translucency appearance, without changing the object’s shape or body color. Moreover, we find the middle-layers of the latent space can successfully predict human translucency ratings, suggesting that translucent impressions are established in mid-to-low spatial scale features. This layer-wise latent representation allows us to systematically discover perceptually relevant image features for human translucency perception. Together, our findings reveal that learning the scale-specific statistical structure of natural images might be crucial for humans to efficiently represent material properties across contexts.
5
Fan, Xiao Hong, Bin Xu, Yong Xu, Jing Li, Lei Shi, Fu Ming Wang, and Jun Pin Lin. "Application of Materials Studio Modeling in Crystal Structure." Advanced Materials Research 706-708 (June 2013): 7–10. http://dx.doi.org/10.4028/www.scientific.net/amr.706-708.7.
Abstract:
Modeling of crystal structure in material science curriculum was practiced and applied to keep it simple and understandable by using MS. The unit cells and atomic configurations are produced to show the theory system of geometry description of crystal structure. Many examples, as diamond, graphite, nanomaterial and advanced carbon materials, are employed to describe the main application of MS in material science teaching. According to these atomic modeling configurations, crystal structures exhibit a clearly and understandable appearance for us. So, the meaning of learning and understanding the related parameters of geometry description of crystal structure was explored with the point which helped students to realize and master the abstract concepts of crystal structure.
6
Naify, Christina, James Stephens, and Aytahn Benavi. "Dynamic characterization of off the shelf polymer composites printed with fused deposition modeling." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 266, no. 1 (May 25, 2023): 1011–19. http://dx.doi.org/10.3397/nc_2023_0122.
Abstract:
Fused deposition modeling (FDM) is the most common and cost effective form of additive manufacturing (AM). Due to the ubiquity of the approach, a range of off the shelf composite materials have been developed by companies, often with the goal of improving the printed part's physical appearance or increasing or decreasing the weight of the part. These composites typically have a base material of a standard FDM printed polymer, with additives such as metal particulates or lightweight filler added. This study will examine the dynamic properties of a set of off the shelf materials to characterize acoustic sound speed, complex elastic moduli, and loss. All of the materials in this study have a base material of polylactic acid (PLA) making it possible to easily print them into multi-material structures. The filler materials showed minimal impact on some viscoelastic properties but resulted in significant changes in acoustic sound speed. Characterization of this type is a critical component in development of an expanded database of material properties for use in design.
7
Sobchenko, V. V., V. A. Zhaivoronok, and H. O. Sobchenko. "Modeling of cooling process of hydroaluminosilicate materials." Кераміка: наука і життя, no. 3(52) (September 30, 2021): 21–25. http://dx.doi.org/10.26909/csl.3.2021.3.
Abstract:
Porous thermal-insulation materials are widely used in building industry, the advantages of which are cheapness and efficiency. Their commercial appearance is also important in their implementation. Porous thermal-insulation materials to prevent sticking can be packaged only after cooling and after the main thermal processes and classification.
The process of cooling porous hydroaluminosilicate materials by the method of modeling with the subsequent check on the laboratory equipment with a fluidized bed is investigated in the work. The main thermal process takes place at a temperature of about 300°C. The cooling time of the porous material to a temperature of 20°C, which is about 20 seconds, is calculated, and the need to ensure this time in its classification is indicated. This model allows you to determine with sufficient accuracy the cooling time for particles of different diameters and temperatures.
The process of cooling the obtained thermal insulation material in the production technology occurs simultaneously with its hydrodynamic classification in the cascade classifier of the fluidized bed. It is important to determine the required cooling time of the spherical hydroaluminosilicate material to temperatures close to 20°C and to ensure the presence of particles in the apparatus during this time.
Comparison of experimental data with the results of the mathematical model shows the results with an error of 10%. There is a slight increase in the minimum residence time of a single granule obtained experimentally compared with the calculated.
8
Guo, Jie, Zeru Li, Xueyan He, Beibei Wang, Wenbin Li, Yanwen Guo, and Ling-Qi Yan. "MetaLayer: A Meta-Learned BSDF Model for Layered Materials." ACM Transactions on Graphics 42, no. 6 (December 5, 2023): 1–15. http://dx.doi.org/10.1145/3618365.
Abstract:
Reproducing the appearance of arbitrary layered materials has long been a critical challenge in computer graphics, with regard to the demanding requirements of both physical accuracy and low computation cost. Recent studies have demonstrated promising results by learning-based representations that implicitly encode the appearance of complex (layered) materials by neural networks. However, existing generally-learned models often struggle between strong representation ability and high runtime performance, and also lack physical parameters for material editing. To address these concerns, we introduce MetaLayer , a new methodology leveraging meta-learning for modeling and rendering layered materials. MetaLayer contains two networks: a BSDFNet that compactly encodes layered materials into implicit neural representations, and a MetaNet that establishes the mapping between the physical parameters of each material and the weights of its corresponding implicit neural representation. A new positional encoding method and a well-designed training strategy are employed to improve the performance and quality of the neural model. As a new learning-based representation, the proposed MetaLayer model provides both fast responses to material editing and high-quality results for a wide range of layered materials, outperforming existing layered BSDF models.
9
Gan, Xu Sheng, Hua Ping Li, and Jing Shun Duanmu. "Research on Aviation Material with Aviation Mishap Prediction Model Based on Neural Network and its BP Algorithm." Applied Mechanics and Materials 540 (April 2014): 492–95. http://dx.doi.org/10.4028/www.scientific.net/amm.540.492.
Abstract:
In order to reduce the appearance of aviation material mishap, it is important to predict the aviation material mishap for safety management and decision-making body. Considering the advantage of neural network modeling, an aviation material mishap prediction based on neural network and its BP algorithm model is proposed. An actual example on fight mishap 10000-Hour-Rate data of USAF illustrates that the proposed prediction model has an accurate prediction.
10
Korchagin, Sergey, Ekaterina Pleshakova, Irina Alexandrova, Vitaliy Dolgov, Elena Dogadina, Denis Serdechnyy, and Konstantin Bublikov. "Mathematical Modeling of Electrical Conductivity of Anisotropic Nanocomposite with Periodic Structure." Mathematics 9, no. 22 (November 18, 2021): 2948. http://dx.doi.org/10.3390/math9222948.
Abstract:
Composite materials consisting of a dielectric matrix with conductive inclusions are promising in the field of micro- and optoelectronics. The properties of a nanocomposite material are strongly influenced by the characteristics of the substances included in its composition, as well as the shape and size of inclusions and the orientation of particles in the matrix. The use of nanocomposite material has significantly expanded and covers various systems. The anisotropic form of inclusions is the main reason for the appearance of optical anisotropy. In this article, models and methods describing the electrical conductivity of a layered nanocomposite of a self-similar structure are proposed. The method of modeling the electrical conductivity of individual blocks, layers, and composite as a whole is carried out similarly to the method of determining the dielectric constant. The advantage of the method proposed in this paper is the removal of restrictions imposed on the theory of generalized conductivity associated with the need to set the dielectric constant.
11
Iser, TomáŠ, Tobias Rittig, Emilie Nogué, Thomas Klaus Nindel, and Alexander Wilkie. "Affordable Spectral Measurements of Translucent Materials." ACM Transactions on Graphics 41, no. 6 (November 30, 2022): 1–13. http://dx.doi.org/10.1145/3550454.3555499.
Abstract:
We present a spectral measurement approach for the bulk optical properties of translucent materials using only low-cost components. We focus on the translucent inks used in full-color 3D printing, and develop a technique with a high spectral resolution, which is important for accurate color reproduction. We enable this by developing a new acquisition technique for the three unknown material parameters, namely, the absorption and scattering coefficients, and its phase function anisotropy factor, that only requires three point measurements with a spectrometer. In essence, our technique is based on us finding a three-dimensional appearance map , computed using Monte Carlo rendering, that allows the conversion between the three observables and the material parameters. Our measurement setup works without laboratory equipment or expensive optical components. We validate our results on a 3D printed color checker with various ink combinations. Our work paves a path for more accurate appearance modeling and fabrication even for low-budget environments or affordable embedding into other devices.
12
Tsai, Chi-Yang, Jeng-Wen Lin, Yih-Ping Huang, and Yung-Chieh Huang. "Modeling and Assessment of Long Afterglow Decay Curves." Scientific World Journal 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/102524.
Abstract:
Multiple exponential equations have been successfully fitted to experimental long afterglow decay curve data for some phosphor materials by previous researchers. The calculated decay constants in such equations are used to assess the phosphorescence characteristics of an object. This study generates decay constants from experimental test data and from existing literature for comparison. It shows that the decay constants of an object may not be invariant and that they are dependent on phosphor material, temperature, irradiation intensity, sample thickness, and phosphor density for samples. In addition, the use of different numbers of exponential components in interpretation leads to different numerical results for decay constants. The relationship between the calculated decay constants and the afterglow characteristics of an object is studied and discussed in this paper. The appearance of the luminescence intensity is less correlated to the decay constants than to the time-invariant constants in an equation.
13
Lukash, A. A., and N. P. Lukutsova. "Technological Features of the Production of Embossed Plywood." Solid State Phenomena 284 (October 2018): 999–1004. http://dx.doi.org/10.4028/www.scientific.net/ssp.284.999.
Abstract:
The article describes the technological features of the bonding of a new type of finishing materials made of glued laminated wood – relief plywood. The relevance of the topic and relevance of the questions is dictated by the need to involve more in processing underutilized at the present time of wood of soft deciduous species. Analytical review of publications of Russian and foreign authors showed that the most of the research has been focused on increasing the strength of structural materials and improvement in the appearance of finishing materials received considerably less attention. Therefore, the aim of the research is theoretical and experimental substantiation of the scientific principles enhance the appearance of plywood production by developing three-dimensional pattern on the front surface. Scientific novelty has discussed in the article questions of modeling of processes of formation of the relief. The article theoretically justifies the conditions for obtaining relief on the front surface of the new finishing material without breaking. The practical significance of the research is to study the possibility of improving the appearance of finishing materials with a homogeneous texture to the wide usage of wood of soft hardwoods in the timber and construction industry.
14
Velmre, Enn, Andres Udal, and Mihhail Klopov. "Modeling of Photon Recycling in GaN-Devices." Materials Science Forum 483-485 (May 2005): 1039–42. http://dx.doi.org/10.4028/www.scientific.net/msf.483-485.1039.
Abstract:
The strength of recombination radiation reabsorption in GaN is discussed. For material comparisons a distance-dependent radiative recombination transfer function F(u) is introduced. In spite of high absorption rates of GaN, calculations predict ca. one order of magnitude higher photon recycling efficiency in GaN than in GaAs. Simulations of 2H-GaN p −i −n structures predict appearance of S-shaped forward I/V characteristics due to the generation of extra carriers in the base center. The study of GaN bipolar transistors shows that the radiative recombination will reduce the carrier lifetimes in the base and thereby restrict essentially the achievable current gains.
15
Yi, Sheng-Xian, Zhong-Jiong Yang, and Huang-Xin Xie. "Hot Deformation and Constitutive Modeling of TC21 Titanium Alloy." Materials 15, no. 5 (March 4, 2022): 1923. http://dx.doi.org/10.3390/ma15051923.
Abstract:
Titanium alloys are extensively employed in the fabrication of various aviation structural parts, of which the most crucial processing step is hot working. In order to study the high-temperature deformation behavior of the TC21 titanium alloy, high-temperature tensile tests were performed. The results reveal that the flow stress of the material gradually decreases with an increased strain rate, and the stress increases rapidly with an increase in strain during the deformation of the alloy. Following this, flow stress gradually decreases. Flow stress decreases sharply, and the sample fractures when the appearance of necking and microvoids is observed. The Arrhenius and Radial basis function (RBF) neural network constitutive models are established in order to accurately describe the high-temperature deformation behavior of the material. In the modified Arrhenius model, strain rate indexes are expressed as a function of deformation temperature and strain rates; furthermore, the high prediction ability of the model was obtained. For the Radial basis function, the network parameters were obtained using the trial-and-error method. The established models could better forecast the flow stress of materials, and highly accurate results are obtained using the radial basis function model. The relationships between the stress index and the deformation activation energy with strain indicate that the primary deformation mechanism involves grain boundary slip and viscous slip of dislocations. The process of dynamic recrystallization primarily promotes the softening of the material.
16
Ismail, Nur Faiqa, Muhammmad Aiman Firdaus Bin Adnan, Solehuddin Shuib, and Nik Ahmad Hambali Nik Abd Rashid. "Three-Dimensional Modeling and Finite Element Analysis of an Ankle External Fixator." Applied Mechanics and Materials 899 (June 2020): 94–102. http://dx.doi.org/10.4028/www.scientific.net/amm.899.94.
Abstract:
External fixator has played an important role in repairing fractured ankle bone. This surgery is done due to the several factors which are the bone is not normal position or has broken into several pieces. The external fixator will help the broken bone to grow and remodel back to the original appearance. However, there are some issues regarding to the stability of this fixation. Improper design and material are the major factor that decreased the stability since it is related to the deformation of the external fixator to hold the bone fracture area. This study aims to design a stable structure for constructing delta frame ankle external fixator to increase the stability of the fixation. There are two designs of external fixator with two types of material used in this present study. Both external fixators with different materials are analyzed in terms of von Mises stress and deformation by using a conventional Finite Element Analysis software; ANSYS Workbench V15. The result obtained shows the Model 1 with stainless steel has less stress and deformation distributions compared to the Model 2. Hence, by using Model 1 as the external fixator, the stability of the fixation can be increased.
17
Frolova, Ksenia P., Elena N. Vilchevskaya, and Vladimir A. Polyanskiy. "Modeling of imperfect contacts in determining the effective diffusion permeability." Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy 10 (68), no. 4 (2023): 650–64. http://dx.doi.org/10.21638/spbu01.2023.405.
Abstract:
The work develops a universal approach to acounting for imperfect contacts in determining the effective properties of various nature, namely, effective diffusivity, thermal and electrical conductivity. Imperfect contacts take place when fields at the microlevel are not continuous. The possibility of creating a unified approach is due to the similarity of the governing equations. At the same time, the appearance of imperfect contacts can be caused by microstructural features and by the specifics of the process itself. For concreteness, the effective diffusion permeability is determined, since various reasons for the appearance of imperfect contacts can be considered. The reasons can be associated both with the formation of structural defects and with the presence of the specific segregation effect. The paper generalizes and compares two approaches to accounting for imperfect contacts. In the first case, a field jump is set. In the second case, an inhomogeneity with a thin coating possessing extreme properties is introduced. A comprehensive analysis is carried out on the example of a material with spherical inhomogeneities. Analytical expressions for contribution tensor of the equivalent inhomogeneity are obtained, which results in simplification of generalization of various homogenization methods.
18
Macovei, Olivia. "The Ethics of Synthetic Biology - at the Confluence of Ecoethics and Technoethics." Postmodern Openings 13, no. 3 (August 8, 2022): 234–50. http://dx.doi.org/10.18662/po/13.3/487.
Abstract:
In the case of synthetic biology, the responsibility of humanity for the creation of new technologies that interfere with the processes of natural selection and evolution of species can be invoked, thus annihilating the complex ecological balances and possibly leading to uncontrollable genetic mutations. The big ethical questions are raised by the fact that viral genetic material is hybridized with synthetic genetic material, as well as with the genetic material that underlies the DNA of various living cells, that might interfere with synthetic genetic material - either due to errors in the handling of genetic content or the inability to predict the evolution of synthetic biological systems, an evolution beyond any mathematical modeling that would allow the estimation of biological risks given by the appearance of new species - partially or totally synthetic - and especially by their spread in ecosystems. In this article we will plead for an ethical modeling of technology and a wider communication between ethicist and bio-engineers in order to estimate the directions of technological evolution, especially in the case of synthetic biology.
19
Hossfeld, Max. "Modeling Friction Stir Welding: On Prediction and Numerical Tool Development." Metals 12, no. 9 (August 29, 2022): 1432. http://dx.doi.org/10.3390/met12091432.
Abstract:
This paper reports on a simulation framework capable of predicting the outcomes of the friction stir welding process. Numerical tool development becomes directly possible without the need for previous calibration to welding experiments. The predictive power of the framework is demonstrated by a case study for numerical tool development and validated experimentally. Different tool geometries with high levels of detail and active material flow features are investigated, and their effect on the process outcomes is quantified. The simulation framework is found to be able to predict forces, material flow, temperature fields, weld formation and welding defects a priori, in detail and precisely. This applies to the outer appearance of the weld as well as the location, shape, and size of inner welding defects. Causes for defects can be identified, analyzed and remedied. Compared to the validation experiment, the simulation showed a slight overestimation of the process impact in the case study. Since the framework relies strictly on analytically describable physics, the efforts for modeling the process are moderate considering the precision of the results.
20
Busko, V., A. Cipric, and A. Stulhofer. "Social Networks and Pornography Use as Precursors Of Body Appearance Self-Perception and Satisfaction." Klinička psihologija 9, no. 1 (June 13, 2016): 109. http://dx.doi.org/10.21465/2016-kp-op-0076.
Abstract:
Objective: Following two complementary theoretical approaches to the study on the development of body appearance (dis)satisfaction, this paper examines the potential role of virtual social networks and exposure to pornography in the processes of body appearance perception and satisfaction. Design and Method: The study is done as a part of an ongoing longitudinal research project focused on the role of sexually explicit material in young people’s sexual socialization and health. The analyses to be presented are based on the data collected within the first time point of the project, on the sample of 1278 female second-year high-school students. Key variables included measures of social networks and pornography use, internalization of appearance ideal, body surveillance, and body appearance satisfaction, gathered within the online administration procedures. Structural equation modeling methodology was used to test the hypotheses on the role of body surveillance and internalization processes in the relationship between the measures of pornography and social networks use and the satisfaction with own body appearance. Results: The analyses confirmed partially mediated contribution of the measures of the amount of use of pornography and virtual networks in accounting for the individual differences in body appearance satisfaction. Conclusions: The processes of internalization of appearance ideal, and the measure of body surveillance, seem to have weak but significant mediation role in the relationship between virtual media use and the satisfaction with own body appearance. This work has been fully supported by Croatian Science foundation under the project 9221.
21
Elsayed, Hussein A., and Arafa H. Aly. "Terahertz frequency superconductor-nanocomposite photonic band gap." International Journal of Modern Physics B 32, no. 05 (February 2018): 1850056. http://dx.doi.org/10.1142/s021797921850056x.
Abstract:
In the present work, we discuss the transmittance properties of one-dimensional (1D) superconductor nanocomposite photonic crystals (PCs) in THz frequency regions. Our modeling is essentially based on the two-fluid model, Maxwell–Garnett model and the characteristic matrix method. The numerical results investigate the appearance of the so-called cutoff frequency. We have obtained the significant effect of some parameters such as the volume fraction, the permittivity of the host material, the size of the nanoparticles and the permittivity of the superconductor material on the properties of the cutoff frequency. The present results may be useful in the optical communications and photonic applications to act as tunable antenna in THz, reflectors and high-pass filter.
22
Kozlova, Galina, and Lyudmila Kozlova. "Compositional study of the lost temples in instructional design." проект байкал, no. 69 (November 13, 2021): 150–57. http://dx.doi.org/10.51461/projectbaikal.69.1867.
Abstract:
The article presents the design and research work of the authors and first-year architecture students of Irkutsk National Research Technical University concerning compositional study of lost temples of Irkutsk with the reconstruction of their architectural appearance. The illustrative material was prepared using the students’ works. The complex of Siberian Baroque temples in Irkutsk in the mid-18th – late 19th centuries and various types of church buildings were studied. The work uses modeling as a tool for predicting the architectural appearance of the temple. Sketch drawings and models of the Miracle-Working, Tikhvinsky and Annunciation temples were completed, and the model of the evolution of Siberian Baroque temples was recreated. The main stages of the term project, from building functional, planning and volumetric models to designing image and structural characteristics of the object on the sample board, were presented.
23
Xu, P. F., S. Y. Duan, and F. Wang. "Reverse Modeling and Topological Optimization for Lightweight Design of Automobile Wheel Hubs with Hollow Ribs." International Journal of Computational Methods 17, no. 09 (August 9, 2019): 1950064. http://dx.doi.org/10.1142/s0219876219500646.
Abstract:
Lightweight of wheel hubs is the linchpin for reducing the unsprung mass and improving the vehicle dynamic and braking performance of vehicles, thus, sustaining stability and comfortability. Current experience-based lightweight designs of wheel hubs have been argued to render uneven distribution of materials. This work develops a novel method to combine the reverse modeling technique with the topological optimization method to derive lightweight wheel hubs based on the principles of mechanics. A reverse modeling technique is first adopted to scan and reproduce the prototype 3D geometry of the wheel hub with solid ribs. The finite element method (FEM) is then applied to perform stress analysis to identify the maximum stress and its location of wheel hub under variable potential physical conditions. The finite element model is then divided into optimization region and nonoptimized region: the former is the interior portion of spoke and the latter is the outer surface of the spoke. A topology optimization is then conducted to remove the optimization region which is interior material of the spokes. The hollow wheel hub is then reconstructed with constant wall thickness about 5[Formula: see text]mm via a reverse modeling technique. The results show that the reconstructed model can reduce the mass of 12.7% compared to the pre-optimized model. The present method of this paper can guarantee the optimal distribution of wheel hub material based on mechanics principle. It can be implemented automatically to shorten the time interval for optimal lightweight designs. It is especially preferable for many existing structures and components as it maintains the structural appearance of optimization object.
24
Galashev, Alexander Y., Ksenia A. Abramova, Alexey S. Vorob'ev, Oksana R. Rakhmanova, and Yuri P. Zaikov. "Modeling the UO2 reduction process." Electrochemical Materials and Technologies 2, no. 3 (2023): 20232017. http://dx.doi.org/10.15826/elmattech.2023.2.017.
Abstract:
Methods of molecular dynamics and DFT calculations have been used to study the reduction mechanisms of UO2 as the most representative part of spent nuclear fuel to metallic uranium. It is shown that the critical softening of the combined modulus of elasticity C11-C12 to zero is the reason for the destruction of the UO2 crystal as a result of the removal of oxygen from it. This destruction is accompanied by an order-disorder phase transition in the oxygen subsystem of the crystal under consideration. DFT calculations indicate a continuous decrease in the band gap as oxygen is removed from the UO2 crystal. When the system reaches the composition U2O3, the band gap disappears and the system becomes electrically conductive. The appearance of the dielectric-conductor transition explains the realization of the FFC Cambridge process during the recovery of spent nuclear fuel. The passage of Li+ and Cl– ions of the LiCl melt through cylindrical channels in a UO2 crystal with cross-sectional radii from 0.25 up to 2 nm has been studied. The strength of the external electric field required for the passage of these channels decreases with an increase in the channel cross section, and the number of Cl– ions entering the channel increases. On the walls of the channels that pass ions with charges of both signs, colonies of adsorbed Cl– and Li+ atoms appear separated from each other, between which strong electric fields are formed. The existence of such fields can cause Li+ ions to move deep into the material being reduced.
25
Kuzin, Mykola, Pavel Vovk, and Oleg Kuzin. "Mathematical modelling and mechanics approaches in investigation of structural failure causes." MATEC Web of Conferences 390 (2024): 04010. http://dx.doi.org/10.1051/matecconf/202439004010.
Abstract:
An approach has been proposed for analyzing the causes of failure of parts, which is based on the use of mathematical modeling in calculating mechanical loads and strength parameters by finite-element analysis, followed by an assessment of the durability of the structure using methods of mechanics of damaged media that take into account the accumulation of structural defects in the material of products. The developed approach was used to calculate critical loads that led to the destruction of the crankshaft of a passenger car engine, and to establish the reasons for their appearance, and also allowed to propose technical solutions to eliminate such emergency situations.
26
Rezaeealam, Behrooz, and Behzad Norouzi. "Investigating Ferroresonance Phenomenon in a Single-Phase Transformer with the Effect of Magnetic Hysteresis." Indonesian Journal of Electrical Engineering and Computer Science 2, no. 2 (May 1, 2016): 248. http://dx.doi.org/10.11591/ijeecs.v2.i2.pp248-258.
Abstract:
<p>Ferroresonance is a non-linear phenomenon and very dynamic in the power quality problems. This phenomenon should be carefully analyzed so that preventive measures could be taken before its appearance and prevent injury and damage to electrical power appliances. Ferroresonance is seen more in the middle-voltage networks with supplying unloaded or slightly loaded transformers by cables. The materials used in the manufacture of transformer cores are creates a major role in their dynamic behavior. In this article are used from two types magnetic material GOES and NGOES in the transformer core of single phase. The physical behavior of these materials is considered during the core hysteresis. For modeling the hysteresis loop has been used from Jiles-Atherton method. By using the finite element method and with help COMSOL Multiphysics Software, transformer is simulated in two space dimensions. Laboratory test the transformer core hysteresis loop is described and shows which the Jiles-Atherton model is one of the best known models of hysteresis. The results shows which use of GOES materials in the transformer core is cause Significant reduction the core losses in comparison with the NGOES materials. Also change of ferroresonance mode and the severity its occurrence are the results of changing the material used in the transformer core.</p>
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Asad, Hassan, Khan Ihsanullah, and Muhammad Javaid. "Applications and Prospects of 3D Printing in the Packaging Industry." International Journal of Advanced Engineering Research and Science 10, no. 1 (2023): 055–61. http://dx.doi.org/10.22161/ijaers.101.9.
Abstract:
In this paper four 3D printing technologies fused deposition modeling (FDM), selective laser sintering (SLS), stereo lithography appearance (SLA), and laminated object manufacturing (LOM) were examined for their characteristics its applications. Technology for 3D printing Since the 1980s, when the field of applications first began to take off, rapid advancement has been made. Materials for 3D printing have been introduced. In order to build items with a variety of shape, size, rigidity, and color, it entails layering materials such as plastics, composites, or biomaterials. Another innovation was the use of 3D printing in the engineering of packaging. It has been noted that the benefits of 3D printing technology in the packaging business are unmatched by other comparable packaging production technologies, and that 3D printing technology has a very broad range of competitive advantage through innovation in the future packaging industry. The development of 3D printing raw material technology determines the development of 3D printing technology Development boundary. It has high requirements on the purity, sphericity, particle size distribution, bulk density, oxygen content, fluidity and other properties of metal powder materials.
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Chansatidkosol, Siraprapa, Chutima Limmatvapirat, Suchada Piriyaprasarth, Vipaluk Patomchaiviwat, and Sontaya Limmatvapirat. "Assessment of Shellac as Alternative Material for Preparation of Fused Deposition Modeling (FDM) 3D Printing Filaments." Key Engineering Materials 914 (March 21, 2022): 53–62. http://dx.doi.org/10.4028/p-fz3v68.
Abstract:
The objective of this study was to assess feasibility of applying shellac as a biopolymer filament for using in fused deposition modeling (FDM) 3D printing. The shellac matrices were prepared through hot melt process by heating the ground shellac samples at 80°C in a silicone oil bath under continuous stirring for 15 min. Accelerated stability testing (annealing process) was also performed in order to evaluated thermal stability by re-heating shellac matrices at 80 °C for 12 h and 24 h in a hot air oven. The shellac matrices and annealed shellac matrices were then comparatively characterized. In the present study, all shellac matrices were investigated for physical appearance, acid value, insoluble solid, moisture content and also characterized by instrument analysis including Fourier-transform infrared (FTIR) spectroscopy, powder X-ray diffractometry (PXRD) and thermal analysis. The results demonstrated that shellac with initial heat (80°C, 15 min) and annealed at 80°C for 12 h had similar properties except the annealed shellac at 80°C for 24 h which shown the lower acid value and formed insoluble solid. The melting temperature, decomposition temperature and melting enthalpy of shellac were around 63-64°C, over than 200°C and 23 J/g, respectively. Furthermore, the extruded filament based on shellac was achieved by hot melt extrusion (HME) technique. The findings revealed that the shellac properties might be suitable to fabricate FDM filaments.
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Dimonie, Doina, Nicoleta Dragomir, and Rusandica Stoica. "Attempts to Diminish the Drawbacks of Polylactic Acid Designed for 3D/4D Printing Technology-Fused Deposition Modeling." Materiale Plastice 58, no. 1 (April 5, 2021): 142–53. http://dx.doi.org/10.37358/mp.21.1.5454.
Abstract:
In order to improve thermal behavior and dimensional strability of polylactic acid (PLA) designed both for 3D and 4D printing technology-fused deposition modeling (FDM) using a scalable procedure, the polymer was melt compounded with additives which control the morphology by crystallization and/or reinforcing. Using the formulations which provide polylactic acid (PLA) improved thermo-mechanical properties and desired dimensional stability, the new materials were shaped, on a laboratory line, as filaments for printing technology. The selected compounds were than scaled up on a 50 kg/h compounding line into granules which prove to have good shapability as filaments for printing technology (1.85 +/- 0.05 mm diameter, required ovality, good appearance and smooth surface) and performed properly at 3D printing. The obtained results proved that functional properties of PLA can be improved by various methods so that, depending on the reached performances, the new material can be converted through printing technology into items for performance applications. The novelty of the article is related to the fact that it identifies a modifying solution for controlling the morphology of a type of PLA designed for 3D printing that already has an advanced crystallinity.
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Gigilashvili, Davit, Philipp Urban, Jean-Baptiste Thomas, Jon Yngve Hardeberg, and Marius Pedersen. "Impact of Shape on Apparent Translucency Differences." Color and Imaging Conference 2019, no. 1 (October 21, 2019): 132–37. http://dx.doi.org/10.2352/issn.2169-2629.2019.27.25.
Abstract:
Translucency is one of the major appearance attributes. Apparent translucency is impacted by various factors including object shape and geometry. Despite general proposals that object shape and geometry have a significant effect on apparent translucency, no quantification has been made so far. Quantifying and modeling the impact of geometry, as well as comprehensive understanding of the translucency perception process, are a point of not only academic, but also industrial interest with 3D printing as an example among many. We hypothesize that a presence of thin areas in the object facilitates material translucency estimation and changes in material properties have larger impact on apparent translucency of the objects with thin areas. Computergenerated images of objects with various geometry and thickness have been used for a psychophysical experiment in order to quantify apparent translucency difference between objects while varying material absorption and scattering properties. Finally, absorption and scattering difference thresholds where the human visual system starts perceiving translucency difference need to be identified and its consistency needs to be analyzed across different shapes and geometries.
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Nagiev, Hasan A., and Firuza A. Alieva. "OPTIMAL CONTROL WITH LOAD OF DEVICES FOR HYDRO PURIFICATION OF FUELS TAKING INTO ACCOUNT CHANGE IN SULFUR CONTENT IN INCOMING ROW MATERIAL." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no. 2 (April 7, 2017): 91. http://dx.doi.org/10.6060/tcct.2017602.5457.
Abstract:
The problem of controlling the speed of introduction of raw materials into processing in industrial plants for hydro desulphurization of fuels connected with considerable differences in their sulphur content is discussed. The main production- and logistic problems of appearance of dynamically changing deviations from a number of norms relating to sulphur content in raw materials being fed into cleansing reactor are presented. The problem of selecting such strategy of controlling the current capacity is stated which is optimal both from the points of view of quality indicator of raw material cleanliness and of realizability of the fuel processing volume being planned. The mathematical statement of the problem is given differing from customary problems of positional control by the consideration of quality indicators of raw materials and limitations on maximally admissible output of plants for raw material processing. The principal difference consists in the introduction of stabilizing feedback concerning consumption resource dynamics which can be realized by means of inclusion of a certain Lagrangian function being optimized. The association of this function with function of perturbing factor distribution, i.e. with changeability of sulphur content in raw material turns a conventional problem of static optimization into the problem of optimal control with integral limitation on the current capacity. For solving the stated problem optimal control, the theory has successive approximation method as well as imitational modeling method. The simplest way of solution from algorithmic point of view is the use of imitational modeling method. The playing out of a random quality in solving similar problems is prescribed through generators of random numbers. This problem is solved in the presented paper by way of imitational modeling method using an empirical mathematical model made on the basis of data of passive observation of process operation of a production plant. With the help of computer simulation means a system of imitating an external perturbing factor is created through which synthesis of stabilizing feedback is made relative to realizability of output volume in the predetermined period. Some realizations of feedback are given permitting to perform analysis and offer recommendations for successful solution of the stated problem of optimal distribution of loads under conditions of external perturbances caused by raw material quality. It is demonstrated that for problems with sufficiently prolonged planning interval. When its statistical parameters are safely protected by an arbitrary realization of a random perturbance, programmed control through feedback circuit proves to be more effective and guarantees higher accuracy of process optimality on the whole. For citation:Nagiev H.A., Alieva F.A. Optimal control with load of devices for hydro purification of fuels taking into account change in sulfur content in incoming row material. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N2. P. 91-97.
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Ipatov, A. A., F. dell'Isola, I. Giorgio, I. Rahali, S. R. Eugster, and A. A. Zaikin. "DYNAMICS OF POROVISCOELASTIC PRISMATIC SOLID FOR VARIOUS VALUES OF MATERIAL PERMEABILITY." Problems of strenght and plasticity 81, no. 4 (2019): 416–28. http://dx.doi.org/10.32326/1814-9146-2019-81-4-416-428.
Abstract:
In present paper wave propagation poroviscoelastic solids is studied. Study of wave propagation in saturated porous media is an important issue of engineering sciences. The poroelasticity theory was developed and nowadays is an important to engineering applications. Also research is dedicated to modeling of a slow compressional wave in poroviscoelastic media by means of boundary-element method. Poroviscoelastic formulation is based on Biot's model of fully saturated poroelastic media with a correspondence principal usage. Standard linear solid model is employed in order to describe viscoelastic behavior of the skeleton in porous medium. The boundary-value problem of the three-dimensional dynamic poroviscoelasticity is written in terms of Laplace transforms. Direct approach of the boundary integral equation method is employed. The boundary-element approach is based on the mixed boundary-element discretization of surface with generalized quadrangular elements. Subsequent application of collocation method leads to the system of linear equations, and then to the solution in Laplace domain. Numerical inversion of Laplace transform is used to obtain time-domain solution. The problem of the load acting on a poroelastic prismatic solid is solved by means of developed software based on boundary element approach. An influence of permeability of porous material on dynamic responses is studied. Slow wave phenomena appearance is demonstrated. Viscosity parameter influence on dynamic responses of displacements and pore pressure is studied.
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Pavlov, Kirill Vital'evich. "A Source Complex for the Construction of a Scientifically Based Virtual Reconstruction of the Spaso-Preobrazhensky Cathedral of the Nizhny Novgorod Kremlin of the XIX - early XX Centuries." Историческая информатика, no. 4 (April 2022): 103–34. http://dx.doi.org/10.7256/2585-7797.2022.4.38473.
Abstract:
The article is devoted to the problem of forming a source complex on the history of the Spaso-Preobrazhensky Cathedral of the Nizhny Novgorod Kremlin of the XIX - early XX centuries in order to create its scientifically based virtual reconstruction. As a result of many years of work, the author has collected a significant documentary base on the history of the temple, which includes four large groups of sources: written, pictorial (graphic), cartographic and material (museum exhibits). Each of them is analyzed in detail with the allocation of materials that are most important for the three-dimensional reconstruction of the designated historical object. The paper also discusses methods and technologies for analysis, verification and initial digital processing of pictorial sources from its composition. The scientific novelty of the study is expressed in the fact that for the first time a relevant source complex on the history of the Spaso-Preobrazhensky Cathedral of the 1830s was formed, which radically distinguishes this study from previous excursion and tourist virtual reconstructions of this temple. In addition, the technique of digital processing of visual sources and their translation into 3D format, developed by the author and presented in this article, has a certain novelty, which allows to preserve their original appearance as much as possible. The collected documentary base on the history of the Spaso-Preobrazhensky Cathedral of the Nizhny Novgorod Kremlin allowed us to assert the possibility of its authentic historical virtual reconstruction.
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Jia, Zian, Matheus C. Fernandes, Zhifei Deng, Ting Yang, Qiuting Zhang, Alfie Lethbridge, Jie Yin, et al. "Microstructural design for mechanical–optical multifunctionality in the exoskeleton of the flower beetle Torynorrhina flammea." Proceedings of the National Academy of Sciences 118, no. 25 (June 17, 2021): e2101017118. http://dx.doi.org/10.1073/pnas.2101017118.
Abstract:
Biological systems have a remarkable capability of synthesizing multifunctional materials that are adapted for specific physiological and ecological needs. When exploring structure–function relationships related to multifunctionality in nature, it can be a challenging task to address performance synergies, trade-offs, and the relative importance of different functions in biological materials, which, in turn, can hinder our ability to successfully develop their synthetic bioinspired counterparts. Here, we investigate such relationships between the mechanical and optical properties in a multifunctional biological material found in the highly protective yet conspicuously colored exoskeleton of the flower beetle, Torynorrhina flammea. Combining experimental, computational, and theoretical approaches, we demonstrate that a micropillar-reinforced photonic multilayer in the beetle’s exoskeleton simultaneously enhances mechanical robustness and optical appearance, giving rise to optical damage tolerance. Compared with plain multilayer structures, stiffer vertical micropillars increase stiffness and elastic recovery, restrain the formation of shear bands, and enhance delamination resistance. The micropillars also scatter the reflected light at larger polar angles, enhancing the first optical diffraction order, which makes the reflected color visible from a wider range of viewing angles. The synergistic effect of the improved angular reflectivity and damage localization capability contributes to the optical damage tolerance. Our systematic structural analysis of T. flammea’s different color polymorphs and parametric optical and mechanical modeling further suggest that the beetle’s microarchitecture is optimized toward maximizing the first-order optical diffraction rather than its mechanical stiffness. These findings shed light on material-level design strategies utilized in biological systems for achieving multifunctionality and could thus inform bioinspired material innovations.
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Radzievskiy, R. M., and V. I. Plisko. "Law enforcers recognition level emerging threats based on physical appearance and behavior signs the enemy." Physical education of students 19, no. 1 (February 28, 2015): 50–59. http://dx.doi.org/10.15561/20755279.2015.0108.
Abstract:
Purpose: examine the effectiveness of the training method of differential approach to the choice of means of influence on the action of law enforcers opponent with different levels of aggressiveness. Material : the experiment involved 15 students of the Kyiv National Academy of Internal Affairs and the 15 employees of the State Guard of Ukraine. Results : presented curriculum for special physical and tactical training. The program details the conceptual apparatus of THREATS and DANGERS manifestations of different levels of aggressiveness opponent (case analysis of its motor behavior). The study participants underwent 7 day course focused training. The basis of the course is an advanced theoretical base. The base is aimed at developing knowledge and skills of employees in determining the level of danger. Including threats from testing and modeling episodes of extreme situations the options cadets. Conclusions : In the simulated collision situations with aggressive opponent to the students significantly improved the adequacy of the response to the threat of execution time and within the legal grounds. Recognition was determined by the level of aggressiveness manifest manners enemy, his emotions, motivation, motor behavior, positional arrangement for 2 - 3 seconds. The program contributed to the development of qualities: attention, orientation, perception, motor lead.
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Mechi, Sumeia A., Muhannad Al-Waily, and Aseel Al-Khatat. "The Mechanical Properties of the Lower Limb Socket Material Using Natural Fibers: A Review." Materials Science Forum 1039 (July 20, 2021): 473–92. http://dx.doi.org/10.4028/www.scientific.net/msf.1039.473.
Abstract:
In general, the lower prosthesis consists of socket, leg, ankle, and foot. The socket is the crucial part for connecting the remaining part of the limb and the prosthesis, as it is essential to distribute the load to the amputation patient to provide comfort and add to the proper appearance of the amputation patient. A research that was included methods of manufacturing it, choosing the composite materials necessary for the design, higher durability, lighter weight, and less cost. Previous research used polymer composites reinforced with fibers as glass fibers, carbon fiber, and Kevlar. Other researchers have studied natural fibers' use as reinforcement fiber by mixing resin materials or adding nanomaterials to modify the mechanical properties and reduce costs. After calculating performing the required mechanical tests such as tensile, fatigue, and impact testing, the required properties of the composite material are found, where the prosthesis socket is manufactured below the knee with the application of different loads of the socket. A review of socket models used in developing countries was performed with regard to design, modeling, and finite element analysis (FEA). This review aims to study the material's behavior and mechanical properties by using natural fibers for manufacturing prosthetic sockets. The review discusses the socket manufacture methods proposed to develop the socket industry based on natural fibers to reduce the hot and humid environment using Kenaf and other natural fibers.
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Daniela Kátlovská, Marko Bednárik, Lukáš Hanko, and Juraj Beniak. "FDM technology printing methods." World Journal of Advanced Engineering Technology and Sciences 7, no. 1 (September 30, 2022): 038–43. http://dx.doi.org/10.30574/wjaets.2022.7.1.0085.
Abstract:
3D printing technologies were developed almost 30 years ago and one of their main features is that instead of removing 3D printing adds material layer by layer and the elements are created directly from CAD models. This type of technology offers an advantageous ability to produce components that are complex in shape and material, which cannot by produce by the traditional methods. Intensive research has led to significant advances in technology in recent years in the development and commercialization of new innovative 3D printing processes by modeling molten deposition (FDM), including composite printing. This paper outlines the main methods for creating polymer composite structures using FDM technology. Thanks to the constantly increasing quality of the final product produce by the am machine, there is a much greater connection and appearance between it and the prototype. Many components are already manufactured directly in these machines, so it is not correct to label them as prototypes.
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Osadchiev, Alexander, Roman Sedakov, Alexandra Gordey, and Alexandra Barymova. "Internal Waves as a Source of Concentric Rings within Small River Plumes." Remote Sensing 13, no. 21 (October 24, 2021): 4275. http://dx.doi.org/10.3390/rs13214275.
Abstract:
This study is focused on concentric rings, which are regularly observed by remote sensing of small river plumes located in different regions worldwide. We report new aerial observations of these features obtained by quadcopters and supported by synchronous in situ measurements, which were collected during the recent field survey at the Bzyb river plume in the eastern part of the Black Sea. Joint analysis of remote sensing imagery and in situ data suggest that the observed concentric rings are surface manifestations of high-frequency internal waves generated in the vicinity of the river mouth. The obtained results demonstrate that the propagation of these waves does not induce offshore material transport within the plume induced by shear instability, which was hypothesized in a recent numerical modeling study of this process. We provide an explanation for the appearance of misleading material features in the numerical simulations discussed above. Finally, we discuss directions for future research of high-frequency internal waves generated in small river plumes.
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Chernova, O. G., V. A. Zakharova, D. S. Kalugina, N. V. Chernousova, and A. V. Dedov. "Fuel permeability of thermoplastic polyurethanes after exposure to salt mist." Perspektivnye Materialy 11 (2022): 61–68. http://dx.doi.org/10.30791/1028-978x-2022-11-61-68.
Abstract:
The effect of salt mist exposure on the surface structure and permeability of thermoplastic polyurethane used in the production of temporary storage tanks and transportation of diesel fuel was investigated. After exposure to salt mist, the analysis of microphotographs showed the alignment of the surface of the polymer material. IR spectroscopy revealed a change in the chemical composition of thermoplastic polyurethane, and the appearance of a quaternary ammonium salt, which leads to an increase in the polarity of polymer macromolecules and increases the relaxation rate of the polymer material structure. An approach to modeling the natural loss of diesel fuel during storage in elastic tanks is proposed. The model parameters allowed us to quantify the effect of salt mist on the diffusion permeability of thermoplastic polyurethane for diesel fuel. At a storage temperature below 60 °C after exposure to salt mist, the tightness time increases and the natural loss of diesel fuel decreases during storage in the tank.
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Rogovoy, Anatoli A., Oleg V. Stolbov, and Olga S. Stolbova. "The Microstructural Model of the Ferromagnetic Material Behavior in an External Magnetic Field." Magnetochemistry 7, no. 1 (January 1, 2021): 7. http://dx.doi.org/10.3390/magnetochemistry7010007.
Abstract:
In this paper, the behavior of a ferromagnetic material is considered in the framework of microstructural modeling. The equations describing the behavior of such material in the magnetic field, are constructed based on minimization of total magnetic energy with account of limitations imposed on the spontaneous magnetization vector and scalar magnetic potential. This conditional extremum problem is reduced to the unconditional extremum problem using the Lagrange multiplier. A variational (weak) formulation is written down and linearization of the obtained equations is carried out. Based on the derived relations a solution of a two-dimensional problem of magnetization of a unit cell (a grain of a polycrystal or a single crystal of a ferromagnetic material) is developed using the finite element method. The appearance of domain walls is demonstrated, their thickness is determined, and the history of their movement and collision is described. The graphs of distributions of the magnetization vector in domains and in domain walls in the external magnetic field directed at different angles to the anisotropy axis are constructed and the magnetization curves for a macrospecimen are plotted. The results obtained in the present paper (the thickness of the domain wall, the formation of a 360-degree wall) are in agreement with the ones available in the current literature.
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Svynarenko, Y., V. Korotkov, S. Kobzan, and O. Pomortseva. "MODEL OF RESTORATION OF MONUMENTS OF ARCHITECTURE AND URBAN PLANNING USING GEOINFORMATION TECHNOLOGIES." Municipal economy of cities 3, no. 170 (June 24, 2022): 278–85. http://dx.doi.org/10.33042/2522-1809-2022-3-170-278-285.
Abstract:
The article considers the current problem of preservation and development of the historical appearance of cities after the end of hostilities. Due to non-compliance with certain limits of modernization of building design (especially historical monuments), the city may lose its historic center, or its architectural ensemble may become unattractive to citizens and tourists. The aim of the article is to study the historical experience of rebuilding war-torn buildings and architectural ensembles and to develop an algorithm for the restoration of architectural and urban monuments with the necessary infrastructure. The authors of this study solve the following tasks: grouping the world experience of reconstruction of historical centers and neighborhoods of war-torn cities in four ways. Due to the fact that the task is quite extensive, it was divided into logical semantic blocks-stages and described in detail each of them. Methods that will help solve this problem – to attract as many Ukrainian specialists as possible. Creating a spatial database that should systematize information from the pre-war appearance of the city and help specialists in geographic information systems and specialists in other fields in solving this complex problem. The need for a comprehensive assessment of damage and destruction was emphasized. An approximate material assessment of losses and development of a plan of further recovery measures is required for each individual structure. And only after the previous work it will be possible to perform a mass laser scan. Laser scanning data will be the basis for further three-dimensional modeling of buildings to be restored. After completing this series of actions, it will be possible to create projects for the modernization of renovated buildings and involve students and teachers in the implementation of architectural and construction schools in the city. The methods used in the article are geoinformation three-dimensional modeling of architectural structures using laser scanning. As a result of the study, the authors proposed a five-step algorithm that can prevent post-war chaos in recreating the original appearance of cities and rationally distribute tasks among implementing organizations, monitor their work and reproduce the appearance of the city as accurately as possible. The expediency of involving representatives of the postmodern school in the restoration of the original historical appearance of cities was also questioned.
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Yan, Gong Xing, and Xiao Rong Wang. "Three Dimensional Simulation and Repair of Skull Maxilla and Dentition Based on CT Scanning and Laser Sintering Technologies." Advanced Materials Research 538-541 (June 2012): 1857–61. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.1857.
Abstract:
Obtain a prosthesis and carry out maxillofacial repair by rapid prototyping technology on the basis of three dimensional finite element model of maxilla skull and dentition which is obtained through preliminary restoration done on a skull exemplar as modeling material and through spiral CT scanning and three dimensional imaging technologies. Thus, a vivid restored three dimensional biomechanical model and prosthesis of maxilla skull and dentition is obtained, based on which, the form and functions can be restored well after repair. Individual defect model and prosthesis model can be built according to different plans designed for different patients. By which, a complete idea for maxilla and dentition repair can be achieved with pleasing in appearance on patients, low cost and less post-operative complications.
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Wang, Xiao Rong, and Shi Wei Chen. "Three Dimensional Simulation and Repair of Skull Maxilla and Dentition Based on CT Scanning and Laser Sintering Technologies." Applied Mechanics and Materials 233 (November 2012): 416–19. http://dx.doi.org/10.4028/www.scientific.net/amm.233.416.
Abstract:
Obtain a prosthesis and carry out maxillofacial repair by rapid prototyping technology on the basis of three dimensional finite element model of maxilla skull and dentition which is obtained through preliminary restoration done on a skull exemplar as modeling material and through spiral CT scanning and three dimensional imaging technologies. Thus, a vivid restored three dimensional biomechanical model and prosthesis of maxilla skull and dentition is obtained, based on which, the form and functions can be restored well after repair. Individual defect model and prosthesis model can be built according to different plans designed for different patients. By which, a complete idea for maxilla and dentition repair can be achieved with pleasing in appearance on patients, low cost and less post-operative complications.
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SOTNYCHOK, O. "PEDAGOGICAL CONDITIONS FOR THE DEVELOPMENT OF COMPOSITIONAL AND FIGURATIVE THINKING OF 5TH-6TH GRADE STUDENTS BY MEANS OF MODELING AND SKETCHING WHEN TEACHING CONSTRUCTION MATERIALS PROCESSING TECHNOLOGIES." Scientific papers of Berdiansk State Pedagogical University Series Pedagogical sciences 1, no. 2 (September 30, 2023): 306–16. http://dx.doi.org/10.31494/2412-9208-2023-1-2-306-316.
Abstract:
The article examines the pedagogical conditions for the development of compositional thinking of 5th-6th grade students by means of modeling and sketching in the teaching of construction materials processing technologies. The problem of developing the creative potential and aesthetic competence of students in the learning process becomes especially relevant in the conditions of the modern educational environment, where great emphasis is placed on the development of creative thinking and practical skills. It has been found that compositional and figurative thinking is a key component in the process of professional growth of students of construction materials processing technology. The use of modeling and sketching allows students to creatively approach the solution of technical problems, promotes the development of aesthetic perception and analytical skills. The role of layout as a means of visualizing an idea and structuring the concept of material processing is outlined. Mock-ups allow students to test and refine their ideas before moving on to practical production. In particular, they help to evaluate the appearance and functionality of the future product, detect possible defects in advance and help to eliminate them. The importance of sketches as a tool for creative search and self-expression is also considered. Sketches help students create model drawings, which are the basis for further creation of the product. Using them allows students to focus on details and maintain the necessary proportions in their projects. In the context of learning technologies for processing construction materials for students of grades 5-6, it was found that compositional thinking is an essential aspect that contributes to the formation of their creative abilities and the development of imagination and critical thinking. In particular, it is stated that the ability of students to understand the connections between elements and the ability to create artistic compositions from materials are key in the process of processing materials. Keywords: compositional and figurative thinking, modeling, sketching, construction materials processing technology, labor training, 5-6 grade students, creativity, pedagogical conditions, psychological and pedagogical aspects.
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Salem, Marwa S., Ahmed Shaker, and Mostafa Mohamed Salah. "Device Modeling of Efficient PBDB-T:PZT-Based All-Polymer Solar Cell: Role of Band Alignment." Polymers 15, no. 4 (February 9, 2023): 869. http://dx.doi.org/10.3390/polym15040869.
Abstract:
In this study, we present some design suggestions for all-polymer solar cells by utilizing device simulation. The polymer solar cell under investigation is formed by a photoactive film of a blend comprising PBDB-T as a polymer donor and PZT as a polymerized small molecule acceptor. The initial cell is based on a fabricated cell whose structure is ITO/PEDOT:PSS/PBDB-T:PZT/PFN-Br/Ag, which has a power conversion efficiency (PCE) of about 14.9%. A calibration procedure is then performed by comparing the simulation results with experimental data to confirm the simulation models, and the material parameters, implemented in the SCAPS (Solar Cell Capacitance Simulator) simulator. To boost the open circuit voltage, we investigate a group of hole transport layer (HTL) materials. An HTL of CuI or P3HT, that may replace the PEDOT:PSS, results in a PCE of higher than 20%. However, this enhanced efficiency results in a minor S-shape curve in the current density-voltage (J-V) characteristic. So, to suppress the possibility of the appearance of an S-curve, we propose a double HTL structure, for which the simulation shows a higher PCE with a suppressed kink phenomenon due to the proper band alignment. Moreover, the designed cell is investigated when subjected to a low light intensity, and the cell shows a good performance, signifying the cell’s suitability for indoor applications. The results of this simulation study can add to the potential development of highly efficient all-polymer solar cells.
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Guo, Yang, Xiangguo Zeng, Huayan Chen, Tixin Han, Heyi Tian, and Fang Wang. "Molecular Dynamics Modeling of the Effect of Nanotwins on the Superelasticity of Single-Crystalline NiTi Alloys." Advances in Materials Science and Engineering 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/7427039.
Abstract:
The objective of this work is to simulate the superelasticity and shape-memory effect in a single-crystalline nickel-titanium (NiTi) alloy through a molecular dynamics (MD) study. Cooling and heating processes for this material are reproduced to investigate the temperature-induced phase transformation in its microstructure. It is found that the martensitic transformation and its reverse process occur accompanied by an abrupt volume change, and the transformed variants lead to the appearance of the (001) type compound twin. In addition, the transform temperatures for martensite start (Ms) and austenite finish (Af) are determined, respectively. The results indicate that when the temperature is beyond Af during the compressive loading-unloading, the superelastic behavior becomes pronounced, which is attributed to the role of nanotwins on the transformation from the austenitic phase (B2) to martensitic phase (B19′). Compared to existing experimental data, a reasonable agreement is achieved through the modeling results, highlighting the importance of the compound twins for dominating the superelasticity of nanostructured NiTi alloys.
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Jacobs, Courtney, Marcia McIntosh, and Kevin M. O’Sullivan. "Making Book History: Engaging Maker Culture and 3D Technologies to Extend Bibliographical Pedagogy." RBM: A Journal of Rare Books, Manuscripts, and Cultural Heritage 19, no. 1 (May 17, 2018): 59. http://dx.doi.org/10.5860/rbm.19.1.59.
Abstract:
Once highlighted as a hobbyist’s novelty, allied technologies such as 3D scanning, 3D modeling, and 3D printing are fueling vital new advances in a diversity of fields: in biomedical research, human tissue is being 3D printed to form human organs; the development of 3D printed titanium parts in aerospace engineering will save airplane manufacturers millions of dollars per plane; and 3D printing allows mathematicians to create intricate physical representations of geometric models that are otherwise difficult to visualize. Though 3D technologies have only recently gained a similar foothold throughout the humanities, the results are no less encouraging. Perhaps unsurprisingly, these projects focus in large part upon furthering our understanding of physical artifacts. Recent examples range from detailed replicas of delicate fossils and high-resolution 3D scans of engraved wooden blocks to 3D models of damaged paintings and fragile medieval artifacts. Application of these technologies naturally aligns with the study of material culture, facilitating the understanding of and access to rare and delicate materials. The appearance of 3D technologies within special collections is thus a fitting development.
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Mizonov, V. Е., A. V. Mitrofanov, E. V. Basova, and E. A. Shuina. "Theoretical study of non-linear heat conduction in multi-layer medium with phase transformation in the layers." Vestnik IGEU, no. 1 (2020): 53–59. http://dx.doi.org/10.17588/2072-2672.2020.1.053-059.
Abstract:
The heat conduction is an important part of heat transfer processes in power engineering, civil engineering, chemical technologies, etc. Variety of researches is devoted to theoretical and experimental study of the heat transfer by the heat conduction. At present, the main attention is concentrated on the non-linear heat conduction when the material properties change with the temperature variation, and the outside conditions change with time. One of the reasons of non-linearity appearance is the phase transformation in the material due to its melting, or drying. The problems of modeling of such processes are also set up and solved in many works. However, the overwhelming majority of such works is related to single-layer materials but not to multi-layer once. Modeling of the heat conduction in a multi-layer medium with phase transformation in its separate layers requires additional investigation, which is the objective of the present paper. In order to solve the problem, the method of mathematical modeling is used. The model uses the mathematical tools of the theory of Markov chains. It is adapted to the case of multi-layer medium, the phase transformation can occur in separate parts of which. The heat transfer by heat conduction and heat processes during the phase transformation are described by the classical equations of heat balance. The numerical experiments were used to investigate the influence of parameters on the process behavior. A mathematical model that allows describing transient heat processes in a multi-layer medium with the possibility of phase transformation in its separate layers is developed. The results of heat process calculation for heating up the three-layer wall with the low-melt intermediate layer surrounded by high-melting layers are presented. The obtained results are consistent physically and validate workability of the model. The developed model of non-linear heat conduction in multi-layer medium with phase transformation in its layers can be successfully used to calculate various physicochemical processes in the layers: drying, freezing and defrosting, pyrolysis, and others.
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Wildemann, V. E., M. P. Tretyakov, and A. I. Mugaratov. "Modeling the deformation process of a plate with a stress concentrator taking into account the postcritical stage of material deformation." PNRPU Mechanics Bulletin, no. 3 (December 15, 2020): 32–40. http://dx.doi.org/10.15593/perm.mech/2020.3.04.
Abstract:
Postcritical deformation of a material is a process which is characterized by a decrease of stress during growing deformations as a result of accumulation of structural damage. The design becomes unable to withstand the external load only when zones with weakened connections are developed enough. Evolution of postcritical deformation zones can occur with an increase of the external load applied to the construction. It means that taking into account the softening of the material allows determining the strength and deformation reserves of constructions more accurately. The mathematical formulation of the boundary value problem of supercritical deformation mechanics is given in the paper. The features of the experimental study of the postcritical stage of material deformation are listed. Strain curves of various steels with a long section of softening are obtained. Numerical solutions for the problems of deforming a thin plate with stress concentrators of different geometries under kinematic loading are obtained. Piecewise linear approximations and real strain curves of steel 20 and steel 40Cr4 obtained experimentally are considered. The evolution of zones of postcritical deformation in the material is considered. The correspondence between the value of the decline modulus and the nature of the evolution of the softening zones is determined. A stress plot is constructed that reflects how the complete material deformation diagram is realized near the concentrator. The calculated loading diagrams are constructed. It is noted that even after the appearance of softening zones, an increase in external load is possible. The strength and deformation resources of structures are determined, and the influence of the geometry of the stress concentrator on their values is considered. It is noted that the consideration of softening in modeling the behavior of structures with stress concentrators is appropriate.
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Wuttmann, Michel, François Briois, Béatrix Midant-Reynes, and Tiphaine Dachy. "Dating the End of the Neolithic in an Eastern Sahara Oasis: Modeling Absolute Chronology." Radiocarbon 54, no. 3-4 (2012): 305–18. http://dx.doi.org/10.1017/s0033822200047093.
Abstract:
The Neolithic site KS043, excavated by the Institut français d'archéologie orientale (IFAO), is situated in the southern basin of the Kharga Oasis (Egypt). It is one of the very few stratified prehistoric sites of the eastern Sahara. The archaeological remains were found near artesian springs that provided water for pastoralists during the dry Middle Holocene. In situ settlement features provided well-preserved material (charcoal, ashy sediment, ostrich eggshell) sufficient to perform radiocarbon dating in the IFAO laboratory in Cairo by the conventional liquid scintillation method. In 2 cases, ostrich eggshell and charcoal within the same in situ context gave significantly different results of, respectively, ∼600 and ∼1200 yr younger dates for the ostrich eggshells. The strong discrepancy is here highlighted for the first time and we suggest that it may be linked with postdepositional phenomena in the vicinity of the artesian springs. A thorough review of 14C dates available for the Holocene in eastern Sahara shows that ostrich eggshells have been widely used. They seem slightly more prone to be discarded than other material but were never the object of a particular study in this context. Bayesian modeling shows that the Neolithic occupation at site KS043 spans a range from 5000 to 3950 cal BC (and concentrated around 4600–4350 cal BC). Characteristic flint tools and pottery relate this occupation to the end of the Neolithic and show links with the Tasian culture, confirming the timing of the presence of this cultural complex in the desert before its appearance in the Nile Valley.