Interior Corner Research Articles

Lattice points on polyominoes of inversion sequences

Inversion sequences of length n are positive integer sequences e 1 e 2 …e n such that 1 ≤ ei ≤ i for all 1 ≤ i ≤ n. These sequences are in bijection with the permutations of [n]. This paper focuses on the polyomino or barpgraph representation of the inversion sequences. More precisely, we study the distribution of lattice points on these polyominoes. We find the generating functions respect to the length, the number of interior vertices, corners, and vertices of a given degree. We also give simple explicit formulas for the total values of these parameters over all polyominoes of inversion sequences of length n. Throughout this work, we use symbolic computer algebra to facilitate the computations.

Description of a new Asian Leaf Litter Toad of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) from southern Guizhou Province, China.

The Asian leaf litter toads of the genus Leptobrachella Smith, 1925 (Anura, Megophryidae) inhabit the forest floor and rocky streams in hilly evergreen forests and are widely distributed from southern China, west to north-eastern India and Myanmar, through mainland Indochina to Peninsular Malaysia and the Island of Borneo. A new species of the Asian leaf litter toad genus Leptobrachella from Guizhou Province, China is described. Molecular phylogenetic analyses, based on mitochondrial 16S rRNA and COI genes and nuclear RAG1 gene sequences indicated that the new species is genetically divergent from its congeners. The new species could be distinguished from its congeners by a combination of the following characters: (1) body of medium size in males (SVL 31.9 - 32.9 mm); (2) distinct black spots present on flanks; (3) toes rudimentarily webbed, with wide lateral fringes; (4) skin on dorsum shagreened with fine tiny granules and short ridges; (5) heels overlapped when thighs are positioned at right angles to the body; (6) tibia-tarsal articulation reaching interior corner of the eye.A new species of the Asian leaf litter toad genus Leptobrachella from Guizhou Province, China is described. Molecular phylogenetic analyses, based on mitochondrial 16S rRNA and COI genes and nuclear RAG1 gene sequences indicated that the new species is genetically divergent from its congeners. The new species could be distinguished from its congeners by a combination of the following characters: (1) body of medium size in males (SVL 31.9 - 32.9 mm); (2) distinct black spots present on flanks; (3) toes rudimentarily webbed, with wide lateral fringes; (4) skin on dorsum shagreened with fine tiny granules and short ridges; (5) heels overlapped when thighs are positioned at right angles to the body; (6) tibia-tarsal articulation reaching interior corner of the eye.

Bubble migration in containers with interior corners under microgravity conditions

Bubble migration in containers with interior corners under microgravity conditions

A study on the effect of opening location on ultimate load capacity of an orthogonal solid slab

The aim of the research is to study the effect of the position of the opening on the ultimate load capacity of the orthogonal solid slab. A yield line theory is used for the prediction of the ultimate load capacity of an orthogonal concrete slab with and without rectangular corner opening subjected to uniformly distributed load (UDL). In this study, two locations of the opening are considered: the rectangular opening provided at the corner and the interior corner of the slab. All possible governing, geometrically admissible, collapse mechanisms were identified, virtual work equations were derived, and to solve the equations a computer program has been developed. The same aspect ratios of the slab and the opening, and opening sizes up to 0.4 times the slab length the were considered. Four boundary conditions of the slab with different opening sizes are considered to present the design charts for affine coefficients.

Designed Concave Octahedron Heterostructures Decode Distinct Metabolic Patterns of Epithelial Ovarian Tumors.

Epithelial ovarian cancer (EOC) is a polyfactorial process associated with alterations in metabolic pathways. A high-performance screening tool for EOC is in high demand to improve prognostic outcome but is still missing. Here, a concave octahedron Mn2 O3 /(Co,Mn)(Co,Mn)2 O4 (MO/CMO) composite with a heterojunction, rough surface, hollow interior, and sharp corners is developed to record metabolic patterns of ovarian tumors by laser desorption/ionization mass spectrometry (LDI-MS). The MO/CMO composites with multiple physical effects induce enhanced light absorption, preferred charge transfer, increased photothermal conversion, and selective trapping of small molecules. The MO/CMO shows ≈2-5-fold signal enhancement compared to mono- or dual-enhancement counterparts, and ≈10-48-fold compared to the commercialized products. Subsequently, serum metabolic fingerprints of ovarian tumors are revealed by MO/CMO-assisted LDI-MS, achieving high reproducibility of direct serum detection without treatment. Furthermore, machine learning of the metabolic fingerprints distinguishes malignant ovarian tumors from benign controls with the area under the curve value of 0.987. Finally, seven metabolites associated with the progression of ovarian tumors are screened as potential biomarkers. The approach guides the future depiction of the state-of-the-art matrix for intensive MS detection and accelerates the growth of nanomaterials-based platforms toward precision diagnosis scenarios.

Large-scale test of a 3D steel moment-resisting frame with composite slab subject to penultimate interior column loss

This paper investigates the structural behavior of a typical three-dimensional steel frame-concrete slab substructure (3D composite floor subassembly) subject to a penultimate interior column removal scenario. A two-by-two bay composite floor subassembly is one-third downscaled and quasi-statically pushed down to failure by a specially designed twelve-point loading tree in displacement control mode. Unlike the previous studies where progressive collapse propagates vertically, the current study reveals the possibility of horizontal progressive collapse of 3D composite floor structures that characterized by losing stability of the exterior column. The load-displacement relationships, failure modes, deformation pattern and beam end rotations of the test specimen are presented in detail. Based on the test results, the three load-transferring mechanisms, including flexural action, catenary action and tensile membrane action, are determined and discussed. Besides, the test results are compared with previous test results subject to interior column, edge column and corner column removal scenarios, based on which a structural design and analysis strategy of normal composite buildings against progressive collapse are recommended in this study.

Rectangular C-Device with Circular Transitions: Modelling Approaches and Development of an Equivalent Nonlinear Inelastic Spring for Seismic Analysis

Yield devices of “C” shape, known as C-devices, supplement the energy dissipation sources when installed in earthquake resistant structures. However, the explicit modelling of C-devices is time consuming. Accordingly, this paper presents a new reliable methodology to define and calibrate an equivalent uniaxial inelastic spring that effectively reproduces the expected hysteretic response of a C-device. The shape of the C-device under study resembles that of a rectangular portal frame with circular interior corner transitions to avoid stress concentration and to control the extension of the dissipative region. The characterization of the properties of the equivalent spring is supported by both, finite element (FE) analyses of a family of C-devices and by experimental validation. Two types of FE models are used to predict the response of the C-device. A simple FE model idealizes the device as an inelastic frame with pinned supports, whereas the more elaborate model analyses the device as a C-shaped inelastic plate under in-plane actions and explicitly reproduces the boundary conditions of the plate at the device connections. Results indicate that the FE analysis results and those obtained with the equivalent inelastic spring are in a good agreement with experimental tests for monotonic and reversed cyclic loading.

Rapid Subentire-Domain Basis Functions Method Based on Adaptive Artificial Neural Networks

The subentire-domain (SED) basis functions method has shown its efficiency in solving the electromagnetic problem of large-scale finite periodic structures (LFPSs). However, calculating the expansion coefficients of SED basis functions is very time-consuming due to the consideration of the mutual coupling between all the elements in LFPSs, even after accelerated by conjugate-gradient fast Fourier transform (CG-FFT) and/or fast multipole method (FMM). In this article, based on the physics locations of observation cells, the adaptive artificial neural networks (AANNs) have been employed to rapidly predict the expansion coefficients of SED basis functions on interior cells, edge cells, and corner cells. By involving the AANNs, the mutual coupling between all the elements can be accounted into the neural networks without the construction of the mutual coupling matrix, and the expansion coefficients of SED basis functions can be obtained rapidly. Numerical experiments prove the accuracy and efficiency of the AANN-assisted SED basis functions method.

3D Printed Schematic Model for Extraocular Muscles teaching

There are many difficulties a student or educator can present in the anatomy course. Technological advances and availability of new tools have provided alternatives to improve the learning method.A 3D model of an orbit and ocular globe (OG) was designed and 3D printed. It consisted of a roof, floor, medial and lateral walls, and a posterior wall. The superior and inferior orbital fissures were represented, as well as the common tendinous ring (Zinn's) and the optic canal from which a cylindrical axis extends in a 45° angle, representing the optic nerve (ON). At the end of this axis, a sphere an enarthrosis sphere simulates the OG. The medial wall is parallel to the OG’s axis, while the lateral wall is almost parallel to the ON’s axis. The OG was formed with polygons to allow better perception of the movements. The center of the sphere attached to the ON matches the center of the OG, resulting in the OG rotating without moving within the orbit.Six holes were made in the OG, in which elastic threads were placed. In the anterior half of the OG, a hole for the superior, inferior, medial and lateral surfaces was made, corresponding to the insertions of the superior rectus (SR), inferior rectus (IR), medial rectus (MR), and lateral recti muscles (LR) respectively. On the lateral surface of the posterior half of the OG, a hole in the superior region was made for the insertion of the superior oblique (SO) and another in the inferior region for the insertion of the inferior oblique (IO). The four rectus muscles originate from the annulus of Zinn, and represented with holes that cross the posterior wall of the orbit in the common tendinous ring at the four points of insertion.In the medial wall of the orbit, at the superior anterior corner, a trochlea was made, through which the thread representing the SO passes and is anchored to the posterior wall through a hole that is superior to the hole for the SR. On the same wall, but in the interior anterior corner of the orbit, we designed a hole to anchor the thread that represents the IO. The angles between the axes of the oblique muscles, recti muscles, and the axis of the OG were kept as close to reality as possible. In the model, the axis between the recti muscles and the OG’s is 20° (human orbit is 23°) and between the oblique muscles and the OG’s is 70° (human orbit is 51°).The design allows an internal rotation when tightening the threads that are inserted in the superior half of the OG (SR, SO); if the inferior half are tightened (IR, IO), it causes an external rotation; if the recti are tightened, adduction occurs (except for the LR); if those representing the obliques and the LR are tightened, an abduction occurs; if those inserted in the anterior half of the OG (SR, IR, MR, LR) are tightened, the movement corresponding to its name is produced, and if those inserted in the posterior half are tightened, the movement occurs opposite to what their names indicate (SO, IO).The model is effective and makes learning easier. Student perception has not been surveyed yet. Future version may improve the angle between the oblique’s and the OG’s axis. Pathological finding can also be exemplified.

Anti-collapse behavior of modular steel buildings with corrugated panels

This paper numerically studies the anti-collapse behavior of the modular steel building (MSB) in the scenario of interior module removal and corner module removal. The vertical displacement, lateral displacement and internal force of a six-storey MSB in a sudden module loss are studied. The reasonability by using rigid body assumption in collapse analysis of the MSB is examined. A refined fracture model of the steel is incorporated into ABAQUS via user subroutine, in which the effects of both stress triaxiality and Lode angle on the fracture ductility of the steel are considered. In the pushover analyses, the effects of the horizontal connection, opening of the wall panel and thickness of the wall panel on the collapse resistance and failure mode of the MSB are studied. The dynamic amplification factor (DAF) of the MSB at the collapse limit state is also obtained. It is found that the rigid body assumption may significantly underestimate the displacement and maximum shear force in the horizontal connection of the MSB. Two types of failure modes of the structure are observed, namely, connection failure-induced collapse and module unit failure-induced collapse. Among the studied parameters, the effect of the opening size of the wall panel on the behavior of the structure is the most significant. In the scenario of the interior module removal and corner module removal, the DAFs of the structure at the collapse limit state range from 1.20–1.29 and 1.27–1.50, respectively.

Numerical investigation of flow behavior at the lateral intake using Computational Fluid Dynamics (CFD)

Hydraulic and environmental engineering projects often utilize side channels. The water flow through the lateral intake of channels and rivers is turbulent including separation zone and lateral eddies. This causes many problems, the transfer and deposition of sediments to the sub-channel, being the most serious. In the current work, a hydrodynamic model using the Navier–Stokes equation for the flow of incompressible fluids was studied. Using the CFD software, ANSYS FlUENT 19.2, 3D flow patterns were simulated at a diversion channel. First, the simulation results were confirmed in this study utilizing the experimental data performed by earlier investigation. The results showed good agreement using the comparison between the experimental and numerical results when the k-omega turbulence viscous model was employed. Simulation of the flow pattern was then done at the lateral channel junction using a variety of geometry designs. These improvements include changing the intake's inclination angle and chamfering and rounding the inner corner of the intake mouth instead of the sharp edge.The flow parameters at the diversion including velocity streamlines, bed shear stress, and separation zone dimensions were computed in the current study. The findings demonstrated that changing the 90° lateral intake geometry can improve the flow pattern and bed shear stress at the intake junction. Consequently, sedimentation and erosion problems are reduced.According to the conclusions of this study, a branching angle of 30° to 45° is the best configuration for increasing branching channel discharge, lowering branching channel sediment concentration and lowering Scour depth at the junction region. It was also discovered that modifying the intake inlet's sharp interior corner with specific conditions has a favorable effect on reducing the size of the separation zone. The intake of chamfered inner edge with 30° angle to flow direction (α) and c value of 0.75b was found to be the best model for lowering separation area in this investigation. In addition, the separation area and stress distribution are negatively influenced by the Configuration E model (chamfered edge at 60° angle with the horizontal), notably the greater chamfer size by increasing chamfered vertical distance (c).

The draining of capillary liquids from containers with interior corners aboard the ISS

In this work, we analyze liquid drains from containers in effective zero-g conditions aboard the International Space Station (ISS). The efficient draining of capillary fluids from conduits, containers, and media is critical in particular to high-value liquid samples such as minuscule biofluidics processing on earth and enormous cryogenic fuels management aboard spacecraft. The amount and rate of liquid drained can be of key concern. In the absence of strong gravitational effects, system geometry, and liquid wetting dominate capillary fluidic behavior. During the years 2010–2015, NASA conducted a series of handheld experiments aboard the ISS to observe “large” length scale capillary fluidic phenomena in a variety of irregular containers with interior corners. In this work, we focus on particular single exit port draining flows from such containers and digitize hours of archived NASA video records to quantify transient interface profiles and volumetric flow rates. These data are immediately useful for theoretical and numerical model benchmarks. We demonstrate this by making comparisons to lubrication models for slender flows in simplified geometries which show variable agreement with the data, in part validating certain geometry-dependent dynamical interface curvature boundary conditions while invalidating others. We further compare the data for the draining of complex vane networks and identify the limits of the current theory. All analyzed data is made available to the public as MATLAB files, as detailed within.

Structural Means for Fire-Safe Wooden Façade Design

This study investigates five fire stop variants used to limit the spread of fire on wooden façades. For this purpose, five fire tests using various types of wooden façade claddings and different fire stops were conducted as full-scale tests and compared to the existing findings. The influences and interactions between the material qualities of the external wall behind the façade cladding, the construction type of the wooden façade cladding, the design of the substructure, the depth of the ventilation gap, and the design of the fire stops were investigated. In evaluating the fire stops, the design of the interior corners, the joint design, and the influence of thermal expansion were examined. Finally, design proposals for the design of fire stops at wooden façades in order to limit the spread of fire were derived based on this evaluation. The outlook presents further needs that need to be investigated in the future in order to clarify undiscussed aspects or points that were ultimately not evaluated within the scope of this study.Graphical

Experiment on bubble formation through dynamical wetting transition in a square capillary

We experimentally study the displacement of viscous liquid by gas in a square capillary tube. The liquid is partially wetting in a way that no spontaneous imbibition along the interior corners would occur even in the absence of forced displacement. The gas–liquid interface exhibits a variety of morphologies with an increasing displacement rate. At a low displacement rate, a constantly moving meniscus can be observed, without any liquid deposition on the tube wall. An increase in the displacement rate gives rise to the deposition of two ultra-thin liquid filaments at each corner, which immediately break into tiny droplets. An additional thicker filament is entrained at each corner as the displacement rate further increases, connecting the thinner ones and the meniscus. When the displacement rate is high, liquid films are entrained on the tube wall and eventually collapse, entrapping an amount of gas in the form of Taylor bubbles. Quantitative measurements show that both the thicker filaments and the liquid films retract at constant speeds. Empirical relations predicting the film thickness and the bubble length are proposed and agree with the experimental results.

OpenFOAM Simulations of Late Stage Container Draining in Microgravity

In the reduced acceleration environment aboard orbiting spacecraft, capillary forces are often exploited to access and control the location and stability of fuels, propellants, coolants, and biological liquids in containers (tanks) for life support. To access the ‘far reaches’ of such tanks, the passive capillary pumping mechanism of interior corner networks can be employed to achieve high levels of draining. With knowledge of maximal corner drain rates, gas ingestion can be avoided and accurate drain transients predicted. In this paper, we benchmark a numerical method for the symmetric draining of capillary liquids in simple interior corners. The free surface is modeled through a volume of fluid (VOF) algorithm via interFoam, a native OpenFOAM solver. The simulations are compared with rare space experiments conducted on the International Space Station. The results are also buttressed by simplified analytical predictions where practicable. The fact that the numerical model does well in all cases is encouraging for further spacecraft tank draining applications of significantly increased geometric complexity and fluid inertia.

Simplified Effective Compressive Strengths of Columns with Intervening Floor Slabs

The current design codes discuss the effective compressive strengths of columns, which reflect a decrease in load transfer performance that can occur when columns and slabs have different concrete compressive strengths. The effective compressive strength of a column increases as it is confined by the slab, and the design codes mandate three different effective compressive strengths for interior columns (confinement on four sides), exterior columns (confinement on three sides), and corner columns (confinement on two sides). For both corner and exterior columns, the confinement effect of the slab is significantly smaller than that for the interior column, and there is a more marked decrease in load transfer performance. However, there is still a lack of theoretical studies investigating the effective compressive strengths of the corner and exterior columns. Therefore, based on the analysis model established in previous research, this study has proposed an equation for calculating the effective compressive strengths of the corner, exterior and isolated columns without any confinement effects of the slab. In addition, axial loading tests of isolated columns were conducted and the proposed equation was verified.

Dynamical edge effect factor determination for building components thermal characterization under outdoor test conditions in a PASLINK test cell: A methodological proposal

The thermal characterization of building components in dynamic exterior conditions is crucial for understanding their real performance, particularly if they are passive or active solar elements. In this respect, the PASLINK methodology has stood out as an effective technique for outdoor testing due to its level of development and precision. It is based on the use of a calibrated test cell with interior walls covered by heat flow meters. The accurate determination of the heat flow through the envelope of the cell is essential for the subsequent thermal analysis of the passive/active solar component being tested.Although the walls of a PASLINK cell have a high thermal resistance and minimal thermal bridges, a higher heat flux is inevitable near the inner corners because of the edge effects. This variation is partially detected by heat flow meters, requiring correction factors accordingly named ‘edge effect factors’. Additional heat flow meters strategically arranged in some interior corners are used to determine these factors in a calibration test. The factors thus calculated are used as invariable values in subsequent cell tests. However, the skill and knowledge of the staff conducting the calibration test are fundamental, as human errors can affect this process.This proposal outlines a more objective and reliable new methodology to determine edge effect correction factors. It is based on applying correlations of instantaneous readings of heat flow meters. These correlations are obtained in an initial PASLINK calibration test, but are valid for all subsequent tests. The factors calculated in this way depend on instantaneous test readings and, for this reason, they are dynamic values perfectly adapted to each test.The calibration test of the cell called EGUZKI, located in Vitoria-Gasteiz (Northern Spain), is used to demonstrate the validity of the proposed method. With the current PASLINK calibration test methodology, the calibrated cell obtains a measurement error of 13%, while the proposed new dynamic methodology reduces this error to 6%.Although this new methodology is determined in the context of a PASLINK test cell, it is an extensive method applicable to the correction of heat flow measurements affected by edge effects in general.

Miniaturized Ring Resonator Wideband Bandpass Filter with Wide Stop Band

In this paper miniaturized quarter wavelength rectangular shaped multimode ring resonator bandpass filter with extended diagonal corners and internally located high impedance perturbation stubs, is proposed. Input/output open stubs are tightly coupled to the extended diagonal corners running parallel to the two sides of the ring resonator, implemented to generate wide passband and wide stop-band. Cut-off frequencies can be shifted to the higher side by increasing the length of the sides of resonator. By inserting the perturbation stubs, rectangular ring resonator produces three degenerate modes out of which first two form a wide passband. Small square patch is attached to the opposite interior corners of the ring resonator and T-shaped stub attached to the opposite longer side of the resonator are tightly coupled with feeder line to improve the return loss, insertion loss and skirt-characteristics. Shorter sides of the rectangular ring resonator are bent in U-shaped to increase the effective length of the resonator eventually the bandwidth is widened. Filter is designed and simulated for the center frequency of 3.2 GHz, bandwidth from 2.0 GHz to 4.0 GHz, on dielectric constant 3.38 and thickness 0.508 mm. Electromagnetic simulator Ansoft HFSS is used to optimize the filter dimensions.

Miniaturized Ring Resonator Wideband Bandpass Filter with Wide Stop Band

In this paper miniaturized quarter wavelength rectangular shaped multimode ring resonator bandpass filter with extended diagonal corners and internally located high impedance perturbation stubs, is proposed. Input/output open stubs are tightly coupled to the extended diagonal corners running parallel to the two sides of the ring resonator, implemented to generate wide passband and wide stop-band. Cut-off frequencies can be shifted to the higher side by increasing the length of the sides of resonator. By inserting the perturbation stubs, rectangular ring resonator produces three degenerate modes out of which first two form a wide passband. Small square patch is attached to the opposite interior corners of the ring resonator and T-shaped stub attached to the opposite longer side of the resonator are tightly coupled with feeder line to improve the return loss, insertion loss and skirt-characteristics. Shorter sides of the rectangular ring resonator are bent in U-shaped to increase the effective length of the resonator eventually the bandwidth is widened. Filter is designed and simulated for the center frequency of 3.2 GHz, bandwidth from 2.0 GHz to 4.0 GHz, on dielectric constant 3.38 and thickness 0.508 mm. Electromagnetic simulator Ansoft HFSS is used to optimize the filter dimensions.

Corrugated Box Compression Strength Enhancement

In this study, 5x5x12 single-wall RSC corrugated boxes were strengthened to increase their compression strength using four different methods; horizontal brace, diagonal brace, L-shape corner post, and triangular corner stiffener. All braces are of 2-inch width. Horizontal Brace : Compression strength increased by 9% when the unsupported box height was reduced from 12 inches to 3 inches. Diagonal Brace : Compression strength increased by 8% and 14% for single and double braces, respectively. L-Shape Corner Post : Compression strength increased by 29% and 38% for exterior and interior posts, respectively. Triangular Corner Stiffener : Compression strength increased by 36% when the stiffener depth increased from 0 inch to 9 inches. The interior corner post method was the most effective and most practical.