Number Of Facets Research Articles

Hasse's Siroe, Thirty Years Later: A Veritable Work in Progress

Abstract The article aims at assessing the differences between Hasse's original setting of Metastasio's Siroe in 1733 and the composer's second setting of the same drama, exactly thirty years later, in terms of dramatic, vocal, and musical balance. The two versions will be comprehensively compared with a focus on two main issues. The first is the origin of the two settings, which goes back to two distinct versions of the libretto, originally conceived by Metastasio for Venice and Naples respectively; a different starting point which gave birth to two, largely separate dramatic projects, differentiated by a number of distinctive facets. On the other hand, special attention will be devoted to the play's characters, which, though basically the same in both settings, demonstrate remarkable differences in individual characterisation and overall balance, both as far as drama and music are concerned.

Geometric Simplifications of Natural Caves in Ray-Tracing-Based Propagation Modelling

Natural caves show some similarities to human-made tunnels, which have previously been the subject of radio-frequency propagation modelling using deterministic ray-tracing techniques. Since natural caves are non-uniform because of their inherent concavity and irregular limestone formations, detailed 3D models contain a large number of small facets, which can have a detrimental impact on the ray-tracing computational complexity as well as on the modelling accuracy. Here, we analyse the performance of ray tracing in repeatedly simplified 3D descriptions of two caves in the UK, i.e., Kingsdale Master Cave (KMC) Roof Tunnel and Skirwith Cave. The trade-off between the size of the reflection surface and the modelling accuracy is examined. Further, by reducing the number of facets, simulation time can be reduced significantly. Two simplification methods from computer graphics were applied: Vertex Clustering and Quadric Edge Collapse. We compare the ray-tracing results to the experimental measurements and to the channel modelling based on the modal theory. We show Edge Collapse to be better suited for the task than Vertex Clustering, with larger simplifications being possible before the passage becomes entirely blocked. The use of model simplification is predominantly justified by the computational time gains, with the acceptable simplified geometries roughly halving the execution time given the laser scanning resolution of 10 cm.

Three‐dimensional quantitative analysis on granular particle shape using convolutional neural network

AbstractTo identify all desired shape parameters of granular particles with less computational cost, this study proposes a three‐dimensional convolutional neural network (3D‐CNN) based model. Datasets are made of 100 ballast and 100 Fujian sand particles, and the shape parameters (i.e., aspect ratio, roundness, sphericity, and convexity) obtained by conventional methods are used to label all particles. For the model training, by feeding the slice images of particles into the model, the contour of particles is automatically extracted, thereby the shape parameters can be learned by the model. Thereafter, the model is applied to predict shape parameters of new particles as model testing. All results indicate the model trained based on slice images cut from three orthogonal planes presents the highest prediction accuracy with an error of less than 10%. Meanwhile, the accuracy for concave and angular particles can be guaranteed. The rotation‐equivariant of the model is confirmed, in which the predicted values of shape parameters are roughly independent of orientations of the particle when cutting slice images. Superior to conventional methods, all desirable shape parameters can be obtained by one unified 3D‐CNN model and its prediction is independent of particle complexity and the number of triangular facets, thus saving computation cost.

Evaluation of Automatic Microstructural Analysis of Energy Dispersive Spectroscopy (EDS) Maps via a Python-Based Data Processing Framework

Computer-aided data acquisition, analysis and interpretation have been effectively employed in a number of facets of research recently days generating favorable outcomes. One of the subsets of this technology, the image processing, involves use of images for data extraction and can be implemented for post processing of material characterization results to better understand and predict material features, properties, and behaviors at multiple scales. The current study introduces a unique image processing method based on Python programming language for in-depth analysis of energy dispersive spectroscopy (EDS) results. The method involves an automatic framework developed to use net intensity data from EDS elemental maps and process it to analyze microstructural characteristics such as particle and agglomerate size distribution along with computation of average area occupied by each of the different components and their overlap contained within a single map. The framework developed in this study is implemented to examine the interaction of Cerium (Ce) and Palladium (Pd) particles in membrane electrode assembly (MEA) of an Anion-Exchange Membrane Fuel Cell (AEMFC) and investigate if this approach can be effectively utilized to predict the electrochemical behavior of the fuel cell. The study also discusses how several parameters such as map resolution, map and image filters, brightness, and level of thresholding can influence the computed results and contribute to errors. A detailed evaluation of this method along with its advantages and limitations is also presented. The study concludes that the image processing framework developed in this study is a quick, easy, and reliable method for automatic extraction of underlying data, which is otherwise challenging to compute using other conventional analysis techniques. This method can also be further optimized and tailored to extract more information, which can be valuable for a variety of applications within the clean energy research.

The convex hull of parking functions of length n

Let $\mathcal{P}_n$ be the convex hull in $\mathbb{R}^n$ of all parking functions of length $n$. Stanley found the number of vertices and the number of facets of $\mathcal{P}_n$. Building upon these results, we determine the number of faces of arbitrary dimension, the volume, and the number of integer points of $\mathcal{P}_n$.

Geometric Modeling of Rosa roxburghii Fruit Based on Three-Dimensional Point Cloud Reconstruction

Fruit three-dimensional (3D) model is crucial to estimating its geometrical and mechanical properties and improving the level of fruit mechanical processing. Considering the complex geometrical features and the required model accuracy, this paper proposed a 3D point cloud reconstruction method for the Rosa roxburghii fruit based on a three-dimensional laser scanner, including 3D point cloud generation, point cloud registration, fruit thorns segmentation, and 3D reconstruction. The 3D laser scanner was used to obtain the original 3D point cloud data of the Rosa roxburghii fruit, and then the fruit thorns data were removed by the segmentation algorithm combining the statistical outlier removal and radius outlier removal. By analyzing the effects of five-point cloud simplification methods, the optimal simplification method was determined. The Poisson reconstruction algorithm, the screened Poisson reconstruction algorithm, the greedy projection triangulation algorithm, and the Delaunay triangulation algorithm were utilized to reconstruct the fruit model. The number of model vertices, the number of facets, and the relative volume error were used to determine the best reconstruction algorithm. The results indicated that this model can better reconstruct the actual surface of Rosa roxburghii fruit. The method provides a reference for the related application.

Platonic entanglement

We present a construction of highly entangled states defined on the topology of a platonic solid using tensor networks based on ancillary Absolute Maximally Entangled (AME) states. We illustrate the idea using the example of a quantum state based on AME(5,2) over a dodecahedron. We analyze the entropy of such states on many different partitions, and observe that they come on integer numbers and are almost maximal. We also observe that all platonic solids accept the construction of AME states based on Reed-Solomon codes since their number of facets, vertices and edges are always a prime number plus one.

Numerical modeling of electromagnetic scattering from complex shape object with coating

Abstract Designing and creating invisible samples of military equipment is important modern science and technical problem. Physically, this is equivalent to reducing the object RCS. It requires fast and accurate tools (experimental or theoretical ones) to determine the RCS of different objects to which various means of reducing visibility are applied. The experimental studies require a lot of time and money, also it provides incomplete information about the object. So, it is important to create numerical effective and physically justified method for the theoretical determining of the complex shape objects RCS. There are well known numerical methods such as SBR. However, in this method there is no suitable approach for effective coating calculating, in particular such coating as a tent. The main goal of this paper is proposing a new method for taking into account some coating that is used for the object masking. To improve the accuracy of such modeling, it is necessary to use a large number of facets. Thus, recalculation of the set of parameters for the coating becomes also a difficult and time-consuming task. Therefore, it is important to develop a method for quickly assessing the effect of the certain coating parameters on the object RCS.

A Novel High Concentration Fresnel Lens as a Solar Concentrator

Abstract This paper describes the design methodology for a novel Fresnel lens. The original Fresnel lens is obtained from a plano-convex lens, whose spherical surface is split into a number of divisions (called facets), collapsed onto the flat base. Thus, all the facets of the original Fresnel lens have the same radius as that of the plano-convex lens. The proposed design aims to achieve better ray concentration and reduced spherical aberration than the original Fresnel lens by constructing spherical facets with unequal radii. The centers and radii of facets are constrained so that the ray refracted from the bottom vertex of each facet on one side of the optical axis and the ray refracted from the outer vertex of the corresponding facet on the other side of the optical axis must intersect at the focal plane. The proposed lens design has resulted in a 275% gain in the concentration ratio and a 72.5% reduction in the spherical aberration compared to the original lens of the same aperture diameter and number of facets. The performance of both novel and original Fresnel lenses when used as solar concentrators with a conical coil receiver is evaluated. The novel Fresnel lens led to increased heat gain and resulted in a compact solar collector design.

Nawigacja fasetowa w polskich bibliotekach naukowych

Teza/cel artykułu – Celem artykułu jest przedstawienie aktualnego stanu stosowania nawigacji fasetowej w polskich bibliotekach naukowych. Dokonano porównania zastosowania faset w OPAC tych bibliotek oraz w bibliotekach cyfrowych organizowanych lub współorganizowanych przez te biblioteki. Metody badań – Dokonano analizy zawartości stron internetowych bibliotek, głównie ich narzędzi wyszukiwawczych: OPAC i multiwyszukiwarek (discovery systems). Uwzględniono biblioteki największych, państwowych szkół wyższych oraz Bibliotekę Narodową. Po odnalezieniu narzędzia nawigacji fasetowej dokonywano analizy ilościowej i jakościowej stosowanych faset. Następnie podobna analiza prowadzona była w stosunku do bibliotek cyfrowych, organizowanych lub współorganizowanych przez analizowane biblioteki. Wyniki – Ponad 60% polskich bibliotek naukowych stosuje fasety w swoich narzędziach wyszukiwawczych. Wśród nich najwięcej jest bibliotek uniwersyteckich (78% przebadanych bibliotek), wychowania fizycznego (67%), ekonomicznych (60%) i technicznych (56%). Średnia liczba faset stosowanych w OPAC wynosi 8,7. Nieco mniej faset stosowanych jest w bibliotekach cyfrowych, średnio 8,66. Do najczęściej stosowanych faset należały takie, jak Forma/Typ, Język, Data wydania, Autor/Twórca. Wnioski – Fasety są rozpowszechnionym narzędziem wyszukiwawczym w bibliotekach polskich szkół wyższych. Stosowane są zarówno w ILS (Integrated Library System) zagranicznych, jak i w polskich. Pod względem liczby i rodzaju faset pomiędzy OPAC i bibliotekami cyfrowymi zachodzą bardzo niewielkie różnice, stąd wniosek, że stosowany schemat metadanych ma na to bardzo niewielki wpływ.

Enumerative problems for arborescences and monotone paths on polytope graphs

AbstractEvery generic linear functional on a convex polytope induces an orientation on the graph of . From the resulting directed graph one can define a notion of ‐arborescence and ‐monotone path on , as well as a natural graph structure on the vertex set of ‐monotone paths. These concepts are important in geometric combinatorics and optimization. This paper bounds the number of ‐arborescences, the number of ‐monotone paths, and the diameter of the graph of ‐monotone paths for polytopes in terms of their dimension and number of vertices or facets.

Peculiarities of actualization of sociological, cultural and episodic memory components in the works of the Great Patriotic War

The article studies a complex contaminated process of actualization of semantic components, which explicate various spheres of intentional objectification of general content in the texts of the precedent world “The Great Patriotic War”. The focuses, first of all, on the axiological basis for integrating the components of comparing personal understanding of the precedent phenomenon and its perception in culture. The dominants of psychic and socially oriented elements of the value space acquire their verbalization in the intimization sphere on the basis of texts of special cultural significance. They are analyzed on the basis of the hermeneutic method, which allows revealing the greatest number of facets of both the basic, nuclear area of verbalization, and to delimit the etymological, passive elements of the semantic hierarchy. In addition, in the process of analyzing the core and periphery, the most effective ways of verbalization and intimization of individual overtones of cultural concepts are determined. Within the framework of identifying the mechanisms of reflexive understanding of the phenomena of “feat”, “suffering”, “anger”, the initial contaminated space of modification of nuclear, etymological, historical and personal peripheral components in their inextricable interaction and mutual influence is recreated. The essence of the dismembered diegetic narration as a key technique for guiding the recipient into the process of derivation of the general content of the work with the formation of a common space of perception and understanding is revealed. The key principles of the reader’s presentation and awareness of the “intimacy” of the narrative with mutual reflexive assessment of the event by the reader and the reader’s hypothetical attitude by the author of the work are described. On the basis of the author’s intentional and unconscious reader’s social reflection in the process of actualizing the components of sociocultural memory within the framework of the precedent world of the Great Patriotic War, a complex conceptual-valency space with a multilevel structure is formed in the linguocultural consciousness of the Russian-speaking community, including the components of the author’s episodic memory.

“The role of a negative pressure ventilator coupled with oxygen helmet against COVID-19: a review”

BackgroundThe coronavirus (SARS-COV-2) pandemic has provoked the global healthcare industry by potentially affecting more than 20 14 million people across the globe, causing lasting damage to the lungs, notably pneumonia, ARDS (acute respiratory distress 15 syndrome), and sepsis with the rapid spread of infection. To aid the functioning of the lungs and to maintain the blood oxygen 16 saturation (SpO2) in coronavirus patients, ventilator assistance is required.Materials and methodsThe main purpose of this article is to outline the need 17 for the introduction of a non-invasive negative pressure ventilator (NINPV) as a promising alternative to positive pressure 18 ventilator (PPV) by elucidating the cons of non-invasive ventilators in clinical conditions like ARDS. Another motive is to 19 profoundly diminish the rate of infection spread by the employment of oxygen helmets, instead of endotracheal intubation in 20 invasive positive pressure ventilator (IPPV) or non-invasive positive pressure ventilator (NIPPV) like face masks and high-flow 21 nasal cannula (HFNC).Result and conclusionThe integration of oxygen helmet with NPV would result in a number of notable facets including the 22 degree of comfort delivered to patients who are exposed to various ventilator-induced lung injuries (VILI) in the forms of 23 atelectasis, barotrauma, etc. Likewise, preventing the aerosol-generating procedures (AGP) diminishes the rate of nosocomial 24 infections and providing a better environment to both the patients and the healthcare professionals.

Design and Three-Dimensional Simulation of a Solar Dish-Stirling Engine

Design and three-dimensional simulation of a solar Dish-Stirling (SDS) engine is currently performed. The design starts with the GPU-3 Stirling engine, which is originally built to generate power from the fossil fuel exclusively. The design is conducted through three subsequent phases. Firstly, several parabolic dishes with different rim angles and number of facets are investigated to optimally design the dish concentrator. Secondly, different relative positions of the receiver aperture to the dish focal plane are tested to reach the optimal position. The optical simulation of the solar concentration process is carried out using SolTRACE software. Finally, an optimal design for a cavity receiver that involves a new structure of the heater tubes is performed. The simulation of the engine with the designed receiver is implemented using the commercial CFD code ANSYS FLUENT. Having finished the design, a comprehensive energy analysis of the designed SDS engine is carried out. The results show that a nearly uniform temperature distribution of the heater tubes throughout the cycle is achieved. The overall thermal efficiency of the designed SDS engine is about 31.8 % at a DNI of 1000 W/m2.

Stress evolution in elastically heterogeneous and non‐linear fluid‐saturated media with a Green's function approach

AbstractClassical analytical solutions of linear elasticity are used as auxiliary solutions to solve non‐linear, and elastically heterogeneous problems on fluid‐saturated media. The 2D Kelvin's solution for a homogeneous space is considered here for simplicity sake. The material non‐linearity could be due to irreversible deformations or non‐linear elasticity response typical of 4D analysis as it is done here. The general procedure relies on a discrete collocation method and a fixed point iterative approach to construct the displacement field. The method is validated by comparing the numerical results with the analytical solution for a layered cylinder embedded in an infinite space. The h‐convergence is checked numerically illustrating the strong influence of the number of facets used to discretize the boundaries. The convergence of the iterative process based on the displacement norm is of a quasi‐quadratic rate for near homogeneous materials and declines to sub‐linear rates as the contrast in elasticity modulus exceeds 15% of the values considered for the Green's function. The method is then applied to a 2D tilted block region where the depleting reservoir has elasticity parameters function of the volumetric strain, to shed some light on the 4D effects. It is shown that the velocity changes are sensitive to the volumetric strain as well as to the strain in the wave propagating direction. Differences, including the anisotropy due to the structural response at the field scale, between the predictions based on this non‐linear isotropic elasticity and the classical R‐factor approach are finally discussed.

Development of a heat source model for friction stir welding tools considering probe geometry and tool/workpiece interface conditions

Over the past 25 years, friction stir welding (FSW) tools have evolved from simple cylindrical geometries to complex conical profiles which incorporate flutes, threads, and multiple facets. Due to the limits of physical testing, finite element (FE) modeling is widely used to analyze FSW tool behavior. However, simulation accuracy is dependent on the tool/work interface conditions and the heat source model that is used. While a uniform probe/workpiece interface conditions are typically assumed in most heat source models, recent work indicates that slip rates on curved (lobe) and flat (facet) surfaces differ considerably. In the present work, a quick stop device was used to observe the steady-state interface conditions for a hexagonal (three lobes and three facets) probe and a generalized heat source model is proposed for asymmetric tools having an arbitrary number of surfaces. A 3D finite element model based on FLUENT was also developed and used to simulate three different probe configurations. A comparison of simulated and experimental temperature profiles showed good agreement and confirmed that heat generation increases with the number of probe facets but approaches a limit as lobes begin to approximate facet surfaces at small edge lengths. Analysis of FSW welds showed that increasing the number of facets promotes lateral flow and results in a wider plasticized zone. It is expected that the study findings will be useful in improving the accuracy of heat source models and understanding how probe geometry affects welding behavior.

Set-based guaranteed active fault diagnosis for LPV systems with unknown bounded uncertainties

This paper focuses on designing, via the minimization of a suitable cost function, an input sequence to guarantee active fault diagnosis (AFD) of discrete-time linear parameter-varying systems regardless of how the scheduling variables change in the scheduling set. Convex polyhedrons are used to characterize the sets of system uncertainties such that the designed input sequence leads to outputs which are consistent with a unique fault mode or healthy mode. Considering the smoothness and energy of the input sequence simultaneously, the optimal input sequence is obtained by solving a family of linear constrained quadratic programming (LCQP) problems in a brute-force way, which will lead to inefficiency when the number of facets of the interest region becomes large. In order to handle this problem, by analyzing a geometric property of the objective function, the original optimization problem is shown to be equivalent to the minimization of the radius of a hypersphere containing the origin based on a simple linear mapping, which is much more efficient than the brute force-based resolution. At the end of this paper, a numerical example and a vehicle model are used to illustrate the effectiveness of the proposed method.

The role of GABAergic signalling in neurodevelopmental disorders.

GABAergic inhibition shapes the connectivity, activity and plasticity of the brain. A series of exciting new discoveries provides compelling evidence that disruptions in a number of key facets of GABAergic inhibition have critical roles in the aetiology of neurodevelopmental disorders (NDDs). These facets include the generation, migration and survival of GABAergic neurons, the formation of GABAergic synapses and circuit connectivity, and the dynamic regulation of the efficacy of GABAergic signalling through neuronal chloride transporters. In this Review, we discuss recent work that elucidates the functions and dysfunctions of GABAergic signalling in health and disease, that uncovers the contribution of GABAergic neural circuit dysfunction to NDD aetiology and that leverages such mechanistic insights to advance precision medicine for the treatment of NDDs.

Complexity of linear relaxations in integer programming

For a set X of integer points in a polyhedron, the smallest number of facets of any polyhedron whose set of integer points coincides with X is called the relaxation complexity {{,mathrm{rc},}}(X). This parameter, introduced by Kaibel & Weltge (2015), captures the complexity of linear descriptions of X without using auxiliary variables. Using tools from combinatorics, geometry of numbers, and quantifier elimination, we make progress on several open questions regarding {{,mathrm{rc},}}(X) and its variant {{,mathrm{rc},}}_mathbb {Q}(X), restricting the descriptions of X to rational polyhedra. As our main results we show that {{,mathrm{rc},}}(X) = {{,mathrm{rc},}}_mathbb {Q}(X) when: (a) X is at most four-dimensional, (b) X represents every residue class in (mathbb {Z}/2mathbb {Z})^d, (c) the convex hull of X contains an interior integer point, or (d) the lattice-width of X is above a certain threshold. Additionally, {{,mathrm{rc},}}(X) can be algorithmically computed when X is at most three-dimensional, or X satisfies one of the conditions (b), (c), or (d) above. Moreover, we obtain an improved lower bound on {{,mathrm{rc},}}(X) in terms of the dimension of X.

A new species of the Simulium (Gomphostilbia) ceylonicum species-group (Diptera: Simuliidae) from Thailand

A new black fly species, Simulium (Gomphostilbia) pangsidaense, is described on the basis of adult female, male, pupal exuviae and mature larvae from Pang Sida National Park, Sa Kaew Province, Eastern Thailand. This new species is placed in the Simulium ceylonicum species-group. It is distinguished from three Thai members of the S. ceylonicum species-group by the following characteristics: from S. (G.) curtatum Jitklang et al. and S. (G.) sheilae Takaoka & Davies by the wide pupal terminal hooks (triangular terminal hooks in the latter two species), and from S. (G.) sheilae and S. (G.) trangense Jitklang et al. by the number of male upper-eye facets in 13 vertical columns and 14 or 15 horizontal rows (10 or 11 vertical columns and 12 or 13 horizontal rows in the latter two species). This is the fourth member of the S. ceylonicum species-group recorded from Thailand.