Interior Of Region Research Articles

Symmetry Criteria For The Equality Of Interior And Exterior Shape Factors With Exact Solutions

Abstract Lienhard [1] reported that the shape factor of the interior of a simply-connected region (Ω) is equal to that of its exterior (R2\Ω) under the same boundary conditions. In that study, numerical examples supported the claim in particular cases; for example, it was shown that for certain boundary conditions on circles and squares, the conjecture holds. In the present paper, we show that the conjecture is not generally true, unless some additional condition is met. We proceed by elucidating why the conjecture does in fact hold in all of the examples analysed by Lienhard. We thus deduce a simple criterion which, when satisfied, ensures the equality of interior and exterior shape factors in general. Our criterion notably relies on a beautiful and little-known symmetry method due to Hersch [2] which we introduce in a tutorial manner. In addition, we derive a new formula for the shape factor of objects meeting our N-fold symmetry criterion, encompassing exact solutions for regular polygons and more complex shapes.

Cylinder flow and noise control by active base blowing

An extensive experimental investigation was undertaken to control the flow and noise characteristics influenced by vortex shedding from a circular cylinder by implementing air blowing at the base of the cylinder. The study synchronised near-field pressure and far-field noise measurements with the wake velocity field to understand the noise reduction mechanism of base blowing. Surface pressure fluctuations were measured using pressure taps distributed around the cylinder's circumference through a remote-sensing method, while velocity measurements were obtained using planar particle image velocimetry at the midspan to examine the flow dynamics. The study unveiled the crucial role of near-field pressure, particularly induced at the shoulders of the cylinder, in generating far-field noise. The rapid vertical flow movement, arising from the interaction between shear layers, was identified as a mechanism responsible for inducing surface pressure fluctuations. This phenomenon occurred as high-momentum fluid moved from the free stream into the interior of the vortex-formation region. By applying base blowing, a remarkable reduction in both near-field pressure and far-field noise was achieved at the fundamental vortex-shedding frequency, with reductions of approximately 20 and 25 dB, respectively, compared with the baseline. Additionally, base blowing caused the shear layers to roll up farther downstream than in the baseline by decreasing the entrainment of fluid-bearing opposite vorticity by the shear layer upstream of the growing vortex. Consequently, there was a substantial decrease in turbulent kinetic energy and Reynolds stress near the cylinder, resulting in slower vertical flow movement and weaker near-field pressure.

Diabetes Mellitus: hospitalizations of adults in a public hospital in the interior of the northern region of Brazil

Diabetes Mellitus: hospitalizations of adults in a public hospital in the interior of the northern region of Brazil

Tightening Poincaré–Bendixson theory after counting separately the fixed points on the boundary and interior of a planar region

Tightening Poincaré–Bendixson theory after counting separately the fixed points on the boundary and interior of a planar region

The lag in agricultural civilization during the Bronze Age in Northeast China: A stable isotope study based on the faunal remains of the Weizili site

In recent years, the feeding patterns of ancient livestock in Northeast China has been a hot but unclear research topic. In this study, we selected 42 faunal collagen samples from the Weizili site (c. 3207–2155 a BP), a typical Bronze Age site, to study the rearing diets of animals based on carbon and nitrogen stable isotopes. The results showed that roe deer (−18.1 ± 3.2‰, 6.4 ± 1.0‰, n = 5) relied on a C3 food, indicating that wild vegetation in Weizili site was primarily composed of C3 plants. Cattle (−14.6 ± 1.9‰, 7.5 ± 0.4‰, n = 9), horses (−16.6 ± 2.7‰, 7.9 ± 2.9‰, n = 3), canines (four were dogs, one was a racoon dog) (−14.8 ± 4.2‰, 7.3 ± 1.3‰, n = 5), pigs (−15.2 ± 4.3‰,6.4 ± 1.2‰, n = 18), and humans (−15.3 ± 0.4‰, 10.6 ± 1.3‰, n = 2) were mainly lived on C3 and C4 mixed food. We compared the results with the available data for the same period of time from different regions, such as the Central Plains region, the Northeast region and the interior of the Northeast region (especially the Liaodong and Liaoxi regions). We concluded that pigs, horses, cattle, dogs and roe deer from the Weizili site were domesticated and that most individuals of these domestic animals were reared by C3 and C4 mixed food, but that there was quite significant diversity in the food sources of a given species, particularly for pigs and roe deer. The isotope results from the Weizili site, together with previously published data from related sites in Northeast China, demonstrated that the level of human intervention in the animal diets was relatively high but different from that of other sites in the same region, such as the Changshan (c. 3000–2200 a BP) and Wanfabozi sites (c. 3000–2300 a BP). Hence, an uneven pace of agricultural development in Northeast China was shown. This comparatively primitive agricultural production lagged behind the agricultural production of the Central Plains region of the same period.

Conformation and Dynamics along the Chain Contours of Polymer-Grafted Nanoparticles.

Densely grafted polymer chains onto spherical nanoparticles produce a diverse range of conformations. At high grafting densities, the corona region near the nanoparticle surface undergoes intense confinement due to a high concentration of chains in the concentrated polymer brush (CPB) region, which results in strong stretching for portions of the chains located within. In contrast, a semi-dilute polymer brush (SDPB) forms farther away from the core and offers reduced confinement for the polymer and more ideal conformations. However, conventional experimental methods are limited in their ability to provide detailed information on individual segments of grafted polymers in these regions; hence, molecular dynamics (MD) simulations are essential for gaining comprehensive insights into the behavior of the grafted chains. This study aims to explore the variations in polymer structure and dynamics that occur along the contour of the grafted chains as influenced by spatial confinement. We focus on the motions and relative positions of each bead along grafted polymers. Our results show that only the initial few grafted beads near the nanoparticle surface exhibit the strong stretching attributed segments in the CPB region of the brush. Increased grafting density or decreased chain flexibility leads to more stretched grafted chains and more aligned bond vectors. As a result, the relaxation dynamics of local regions of the polymer are also strongly influenced by these parameters. Although the grafted beads in the interior of the CPB region are highly sensitive to these parameters, those farther from the nanoparticle core experience significantly diminished effects. In comparison to the Daoud-Cotton (DC) model's predictions of CPB size, beads near the nanoparticle surface show slower dynamic decay, especially in high grafting densities, aligning with the DC model's estimates. Finally, we compare our simulations to previous works for additional insight into polymer-grafted nanoparticles.

An Integral Equation Method Using Periodic Contact-Region Modeling for Analyzing Infinitely Biperiodic Composite Structures

Based on the method of moments (MoM) using Rao–Wilton–Glisson (RWG) basis functions, a new MoM approach to analyze infinitely biperiodic structures is proposed. In this approach, the interior of each dielectric region is analyzed separately using the infinite-space Green’s function, and the periodic boundary conditions are enforced on the exterior regions. A periodic contact-region modeling (PCRM) technique is introduced to model a three-dimensional (3-D) biperiodic composite electromagnetic (EM) structure as a combination of different regions which is connected by the interfaces of successive unit cells. In addition to increasing the versatility of the surface integral equation (SIE) for periodic structures, it is also a straightforward way to decrease the long computation time for interpolating the periodic Green’s functions. Several examples are presented to show both the versatility and efficiency of the proposed method.

Evidence of a link between Amazon fires and lightning

The number of fires in the Amazon region increased dramatically at the beginning of 2022 compared to 2021. Considering that this period is also characterized by a large incidence of cloud-to-ground (CG) lightning in this region, we investigated if these phenomena may be related to each other. Two regions of Brazil were considered in the analysis: Mato Grosso state, on the border of the Amazon region where most of the deforestation occurs, and Amazonas state, in the interior of the Amazon region. In the first four months of 2022, 26,554 fires and approximately 3 million CG lightning flashes in Mato Grosso and 2468 fires and about 3.4 million CG lightning flashes in Amazonas were recorded. By comparison, in 2021, 16,844 fires and approximately 2.7 million CG lightning flashes in Mato Grosso and 1258 fires and about 3.2 million CG lightning flashes in Amazonas were recorded. In this study, we examined whether these phenomena were linked on a 2 to 9-day timescale, utilizing wavelet coherence analysis of both fire and lightning data. Our results indicate that these phenomena are linked (p < 0.05) for several weeks in both regions in both years. Additionally, correlations for 2022 were notably higher (above 0.90 versus 0.80) when the incidence of fires and lightning was higher, lending support to the notion of a relationship between these two events. Considering the periodicity characteristics of our results and that most fires in these regions are human-induced, we conclude that anthropogenic fires may affect lightning activity through aerosol-cloud particle interactions, with additional and not previously documented implications for climate change. Assuming the same is happening in other regions of the planet, we may face a new aspect not considered in the present global climate model projections.

(130) Elektra Delta – on the stability of the new third moonlet

ABSTRACT The aim of this work is to verify the stability of the proposed orbital solutions for the third moonlet (Delta) taking into account a realistic gravitational potential for the central body of the quadruple system (Alpha). We also aim to estimate the location and size of a stability region inside the orbit of Gamma. First, we created a set of test particles with intervals of semimajor axis, eccentricities, and inclinations that covers the region interior to the orbit of Gamma, including the proposed orbit of Delta and a wide region around it. We considered three different models for the gravitational potential of Alpha: irregular polyhedron, ellipsoidal body, and oblate body. For a second scenario, Delta was considered a massive spherical body and Alpha an irregular polyhedron. Beta and Gamma were assumed as spherical massive bodies in both scenarios. The simulations showed that a large region of space is almost fully stable only when Alpha was modelled simply as an oblate body. For the scenario with Delta as a massive body, the results did not change from those as mass-less particles. Beta and Gamma do not play any relevant role in the dynamics of particles interior to the orbit of Gamma. Delta’s predicted orbital elements are fully unstable and far from the nearest stable region. The primary instability source is Alpha’s elongated shape. Therefore, in the determination of the orbital elements of Delta, it must be taken into account the gravitational potential of Alpha assuming, at least, an ellipsoidal shape.

The optimum grain size for strength-ductility combination in metals

A strength-ductility trade-off usually occurs when grains are refined to increase strength. A question arises on if there exists a grain size for the best strength-ductility combination, i.e., with the highest possible strain energy density limit and strength simultaneously. This issue is crucial for guiding the design of strong and tough structural materials. Here we reveal an optimum grain size (doptimum) on the order of a few micrometers, at which the strain energy density limit, estimated as the product of strength and uniform elongation, reaches a maximum while maintaining reasonably high yield strength. The doptimum is found to exist in a series of single-phase FCC, BCC and HCP materials, indicating it as a universal phenomenon. Theoretical models on the grain size-dependence of uniform elongation and ultimate strength are developed by considering dislocation accumulation in grain boundary affected region (Gbar) and grain interior based on the classical Kocks-Mecking-Estrin model. Combined with the Hall-Petch relationship, the models accurately predict the doptimum. Importantly, the models disclose this doptimum to be close to twice of the characteristic width of Gbar (lGbar), suggesting that it is exactly at or near the critical grain size with the strongest intragranular strain gradient effects.

Primal-dual path following method for nonlinear semi-infinite programs with semi-definite constraints

In this paper, we propose a primal-dual path following method for nonlinear semi-infinite semi-definite programs with infinitely many convex inequality constraints, called SISDP for short. A straightforward approach to the SISDP is to use classical methods for semi-infinite programs such as discretization and exchange methods and solve a sequence of (nonlinear) semi-definite programs (SDPs). However, it is often too demanding to find exact solutions of SDPs. In contrast, our approach does not rely on solving SDPs accurately but approximately following a path leading to a solution, which is formed on the intersection of the semi-infinite feasible region and the interior of the semi-definite feasible region. Specifically, we first present a prototype path-following method and show its global weak* convergence to a Karush-Kuhn-Tucker point of the SISDP under some mild assumptions. Next, to achieve fast local convergence, we integrate a two-step sequential quadratic programming method equipped with the Monteiro-Zhang scaling technique into the prototype method. We prove two-step superlinear convergence of the resulting algorithm using Alizadeh-Hareberly-Overton-like, Nesterov-Todd, and Helmberg-Rendle-Vanderbei-Wolkowicz/Kojima-Shindoh-Hara/Monteiro scaling directions. Finally, we conduct some numerical experiments to demonstrate the efficiency of the proposed method through comparison with a discretization method that solves SDPs obtained by finite relaxation of the SISDP.

New Solutions of Nonlinear Equations Constrained by Bounded Variables under Edge Computation

Aiming at the problem of low global convergence and local convergence rate of trust region interior points of bounded variable constrained nonlinear equations, a trust region interior point algorithm for bounded variable constrained nonlinear equations under edge calculation is designed. By constructing the basic function form of nonlinear equations constrained by bounded variables, the boundary of nonlinear equations is determined by Gauss Newton iterative process to ensure the global convergence of changes; solve the original objective function, analyze the trust region subproblem of the unconstrained optimization problem, and generate an acceptable region. The region is generated through two-dimensional example interpretation. The interior points in the acceptable region are determined by the primal dual interior point method, and the interior points in the acceptable region are optimized. With the help of edge calculation, the trust region interior point programming model of bounded variable constrained nonlinear equations is designed to realize the algorithm design. The experimental results show that the designed algorithm can improve the trust region interior point global convergence and local convergence rate of nonlinear equations with bounded variable constraints.

Dynamics of a dengue disease transmission model with two-stage structure in the human population.

Age as a risk factor is common in vector-borne infectious diseases. This is partly because children depend on adults to take preventative measures, and adults are less susceptible to mosquito bites because they generally spend less time outdoors than children. We propose a dengue disease model that considers the human population as divided into two subpopulations: children and adults. This is in order to take into consideration that children are more likely than adults to be bitten by mosquitoes. We calculated the basic reproductive number of dengue, using the next-generation operator method. We determined the local and global stability of the disease-free equilibrium. We obtained sufficient conditions for the global asymptotic stability of the endemic equilibrium using the Lyapunov functional method. When the infected periods in children and adults are the same, we that the endemic equilibrium is globally asymptotically stable in the interior of the feasible region when the threshold quantity $ R_0 > 1 $. Additionally, we performed a numerical simulation using parameter values obtained from the literature. Finally, a local sensitivity analysis was performed to identify the parameters that have the greatest influence on changes in $ (R_0) $, and thereby obtain a better biological interpretation of the results.

SEMIAUTOMATED SYSTEM FOR OPTIMIZING THERMAL COMFORT AND REDUCING RICE WASTE IN THE POULTRY BREEDING PROCESS OF SMALL PRODUCERS FROM THE INTERIOR OF THE AMAZON REGION

In the Amazon region, the reality of the conventional laying poultry production chain consists of farms with structures that are inferior to those in other regions, with a massive presence of small poultry farmers, without a water, food and air conditioning automation system. The need for improvements in the poultry process that the small producer needs to produce can be linked to the relationship of implementing technology for monitoring equipment or systems. Therefore, the motivation of this study was the creation of a semi-automated system to optimize the thermal comfort of birds and reduce feed waste in the laying poultry production process for small producers in the interior of the Amazon region in order to reduce mortality and maximize the profit. The methodology designated for the construction of this research was based on the nature of applied research, with a view to the qualitative-quantitative approach, through technical procedures of a case study. After assembly of the semi-automated system for feeding, adding the total savings for feed consumption would be 1964.20 kg of feed, in reais it would be R$ 7,856.80. And for the ambiance system, we have savings on the energy bill of 60.94 reais a month and 731.31 reais a year. The semi-automated systems suggested for small poultry farmers in the Amazon region theoretically fulfill their objective, both for the improvement of waste and for the provision of animal welfare and increased profitability.

Pressure-driven stochastization of flux surfaces in stellarator equilibria: a review of the experimental observations and their analysis

Stellarator vacuum fields are designed to have a dense set of nested flux surfaces, with only small islands and stochastic regions in the interior of the confinement region. As the plasma pressure is increased, pressure driven currents appear, and they can significantly modify the vacuum field. The question arises whether pressure driven currents can cause significant flux surface breakage. Both the Wendelstein 7-AS and large helical device stellarators had dedicated experimental campaigns to study the limit in those devices. This paper reviews the evidence that the flux surfaces in a significant fraction of the plasma volume were stochastized by the pressure-driven currents in the highest experiments. That phenomenon appears to have been the dominant source of pressure-driven flux surface loss in these experiments.

Elastic recovery induced strengthening effect in copper/ multilayer-graphene interface regions revealed by instrumental nanoindentation

To distinguish the strengthening effect of multilayer graphene (MLG) on the copper matrix from the intrinsic strengthening effect of copper grain boundary (GB), the nanoindentation behavior in the Cu/MLG interface boundary (IB) region is investigated and further compared with those in the copper GB region and pure copper grain interior (GI) regions. The indentation displacement recovery ratio, elastic work ratio, and indentation hardness in the Cu/MLG IB regions are significantly enhanced as compared with those in the copper GB region and copper GI regions. The strengthening effect in the Cu/MLG IB regions can be attributed to the elastic recovery behavior during the unloading period induced by the MLG, which is further confirmed in both the experimental and simulated indentation topography evolutions. In addition, gradient strengthening effect is revealed from the gradual increase in the indentation displacement recovery ratio, elastic work ratio, and indentation hardness with gradual decreasing distance from the MLG in the Cu/MLG IB regions. The findings in this paper can be utilized to precisely enhance the mechanical performance of copper matrix composite materials by tailoring the interfacial microstructure and property.

Skeleton-Based Parametric 2-D Region Representation: Disk B-Spline Curves.

The skeleton, or medial axis, is an important attribute of 2-D shapes. The disk B-spline curve (DBSC) is a skeleton-based parametric freeform 2-D region representation, which is defined in the B-spline form. The DBSC describes not only a 2-D region, which is suitable for describing heterogeneous materials in the region, but also the center curve (skeleton) of the region explicitly, which is suitable for animation, simulation, and recognition. In addition to being useful for error estimation of the B-spline curve, the DBSC can be used in designing and animating freeform 2-D regions. Despite increasing DBSC applications, its theory and fundamentals have not been thoroughly investigated. In this article, we discuss several fundamental properties and algorithms, such as the de Boor algorithm for DBSCs. We first derive the explicit evaluation and derivatives formulas at arbitrary points of a 2-D region (interior and boundary) represented by a DBSC and then provide heterogeneous object representation. We also introduce modeling and interactive heterogeneous object design methods for a DBSC, which consolidates DBSC theory and supports its further applications.

Vortex generation due to internal solitary wave propagation past a sidewall constriction

Abstract

Population history of the Blue-backed Manakin (Chiroxiphia pareola) supports Plio-Pleistocene diversification in the Amazon and shows a recent connection with the Atlantic Forest

It has been hypothesised that rivers serve as biogeographic barriers and Pleistocene forest refuges may explain the rich species diversity observed within Neotropical rainforests. The lack of correspondence between Amazonian and Atlantic forest species in South America is a good model for testing such hypotheses. We used molecular, ancestral area reconstruction, and potential paleodistribution analyses of Chiroxiphia pareola to test above hypotheses and examine the diversification and/or geographical expansion of populations. Six genes, two mitochondrial and four nuclear, were analysed. All population splits were estimated to have occurred in the Pliocene–Pleistocene period, and the occurrence of an Amazon population split was supported by historical river dynamics. Amazonian populations were not monophyletic, and the eastern Amazonian cluster was a sister of the Atlantic Forest population. Molecular divergence occurring between the Amazonian and Atlantic forest populations was low when compared to splits between the lineages separated by Amazonian rivers. During the early to middle Pleistocene era, regions associated with mountain slopes and riverbanks connected the Amazonian and Atlantic Forest populations near the interior of the Brazilian Northeast semiarid region, which might have facilitated species dispersal from Amazonia into the Atlantic Forest. After this point, the populations were separated, and the Atlantic Forest population remained stable until the end of the Pleistocene and Holocene eras when short-range expansion and demographic growth occurred. Our results provide evidence that highlights the role of rivers and historical climate change in the diversification of Amazonian and Atlantic Forest bird species through the Plio-Pleistocene era.

Perceiving Identity of Period Interiors Based on Visual characteristics: Comparing Aesthetics of Renaissance in England and France

Interior spaces are the cradle for activities of the people who use it. These activities reflect the lifestyle of a community. The design of the physical space pertains to the needs of the function it is meant for, while its aesthetics is created to provide the appropriate backdrop to visual and hence emotional satisfaction and pleasure. This is the reason why every Interior bears the signature of the design and ownership of the space. It has been seen that, Civilizations create their own identity within a space by virtue of its Architecture and Decorations which become the Fashion statement for an era. It evolves to signify a style identified with the culture of the particular period and location. However, it is more interesting to observe how remarkably different styles emerge in different locations, though the influence and design of the interiors belong to same historic periods. Although transformations happen over periods of time in history in the same region, but the identity of the interior of a particular region retains its individuality so distinguishable by virtue of its Geometry and Elements. In this paper, a comparison of interiors in England and France during the Renaissance period of 14th-17th Century, attempts to illustrate how the Geometry and the aesthetic elements create the perception of the interior space which is the identity of the style of the period. The innate Geometry of space and visual elements integrates to create a visual experience which goes on to build identity of a period style. The illustrations show how they balance each other to create a general perception for a time period and build an identity for a regional style in fashion. The one that will be known as French or English style of design.