Edge Corner Research Articles

Behaviour of Steel Frames Exposed to Different Fire Spread Scenarios

Structural stability is highly important for the safe evacuation of occupants and safe access to fire-fighters in accidental fire events. In this paper, the effect of fire protection of beams on the fire resistance of heated columns is studied firstly, and the results show that fire protection of beams may have little effect on the behaviours of heated columns as the heating time of fire spread scenario is short in this study. Then, the behaviours of 3D steel frames subjected to seven different fire spread scenarios have been investigated. The effects of fire source location, occurrence time of fire spread, and direction of fire spread on the fire resistance of steel frame are comprehensively studied. In case of horizontal fire spread scenarios with different fire source compartments, collapse occurs when the corner and long edge compartments are fire source compartments. A stable catenary mechanism of beam could improve and control the collapse time and range. The corner column may bear the catenary tensions in two horizontal directions, and the lateral stiffness of corner column should be crucial for the design of structural fire. For the non-insulated steel frame, the maximum temperature and maximum axial force of heated columns appear at same time and collapse finally happens in the scenario that fire spread when the gas temperature of fire source compartment reaches the peak temperature. The time of most adverse spread for the non-insulated steel frame should be that when the gas temperature of fire source compartment reaches the peak temperature. The influence of vertical fire spread on heated columns may be smaller than that of horizontal fire spread, but vertical fire spread had great influence on fire resistance of beam. According to this study, spread range, duration, and fire temperature are the three most critical factors of fire spread, and the adverse horizontal spread scenario could be mainly selected from these factors.

Cutting Features Between Surface Roughness in Feed Direction and Machining State of Radius End Mill Against Inclined Surfaces (In Case of Contour Machining and Five-Axis Machining with Constant Tilt Angle)

Optimum experimental conditions, that realize good surface roughness in feed direction, for a radius end mill against some inclined surfaces is obtained by the Taguchi method. Some cutting features due to the unique shape of the radius end mill are revealed via the degree of influence of various factors, which are calculated by the Taguchi method, and the geometric relationship of some contact states of the tool. The experimental conditions include cutting type, spindle speed, feed rate, depth of immersion, inclination angle, and corner radius. The results revealed that the contact states are highly significant, and can be categorized into three types. Furthermore, bottom and corner edges must be contacted simultaneously in order to obtain good surface roughness.

A New Flank Face Design Leading to an Improved Process Performance when Drilling High-Temperature Nickel-Base Alloys

In previous investigations, the concept of a modified flank face design with a retraction behind the cutting edge was developed. Based on fundamental investigations regarding the mechanical and thermal loads, combined with simulation-based analyses, a new design of the flank face has been created with the largest possible free volume behind the cutting edge while maintaining the mechanical stability required for the challenging machining of nickel-base alloys. This flank face modification allows a greater amount of cutting fluid to flow along the back of the cutting edge at higher velocities while at the same time creating the potential of a friction reduction between the tool tip and bore hole ground. The described concept was implemented on solid carbide twist drills which were then used to machine Inconel 718. The results show that, while tools equipped with a flank face retraction perform up to four times longer compared to standard tools, they tend to reach the end of tool life rather suddenly due to cutting edge chipping. This typically occurred when the maximum width of flank wear land equalled the width of the remaining cutting edge. Since then, further investigations have been carried out in order to refine the concept of the flank face modification. A new design was implemented with regard to a more effective cooling of the flank face, presumably caused by an improved cutting fluid flow velocity particularly at the cutting edge corners. Simulation-based findings, combined with experimental tests of the new prototypes, could reveal that the improved cutting fluid flow in the area of the cutting edges leads to significantly extended tool life and machining performance when drilling Inconel 718.

RIFT: Multi-modal Image Matching Based on Radiation-variation Insensitive Feature Transform.

Traditional feature matching methods, such as scale-invariant feature transform (SIFT), usually use image intensity or gradient information to detect and describe feature points; however, both intensity and gradient are sensitive to nonlinear radiation distortions (NRD). To solve this problem, this paper proposes a novel feature matching algorithm that is robust to large NRD. The proposed method is called radiation-variation insensitive feature transform (RIFT). There are three main contributions in RIFT. First, RIFT uses phase congruency (PC) instead of image intensity for feature point detection. RIFT considers both the number and repeatability of feature points and detects both corner points and edge points on the PC map. Second, RIFT originally proposes a maximum index map (MIM) for feature description. The MIM is constructed from the log-Gabor convolution sequence and is much more robust to NRD than traditional gradient map. Thus, RIFT not only largely improves the stability of feature detection but also overcomes the limitation of gradient information for feature description. Third, RIFT analyses the inherent influence of rotations on the values of the MIM and realises rotation invariance. We use six different types of multi-modal image datasets to evaluate RIFT, including optical-optical, infrared-optical, synthetic aperture radar (SAR)-optical, depth-optical, map-optical, and day-night datasets. Experimental results show that RIFT is superior to SIFT and SAR-SIFT on multi-modal images. To the best of our knowledge, RIFT is the first feature matching algorithm that can achieve good performance on all the abovementioned types of multi-modal images. The source code of RIFT and the multi-modal image datasets are publicly available1.

A Super Anisotropic Wetting Microstructure Based on Combination of Sharp Edge and Sharp Corner

Anisotropic wetting is important in industrial, medical and agricultural applications. In this paper, a novel microstructure performing prominent ultra-anisotropic wetting properties is proposed, with MEMS fabrication process. This microstructure possesses both sharp edge and sharp corner (SESC) in topography. The sharp edge can hinder liquid spreading significantly, whereas the sharp corner enhance spreading. By lithography technology on polymer film, Parylene-C, the microstructure can be tailored into different shapes to achieve various liquid spreading properties, two of which are demonstrated here. 2-D SESC microstructure illustrates ultra-high contact angle difference in parallel and perpendicular directions as high as 93.8°, as well as bidirectional wetting properties. Another microstructure, namely 3-D SESC microstructure, demonstrates specific unidirectional wetting properties. The unique microstructure proposed in this paper provide new ideas for application of controlling liquid spreading on surface. [2019-0077]

Badania etapów zużycia wierzchołka ostrza z promieniem zaokrąglenia z wykorzystaniem modelu matematycznego i geometrycznego

In modern multiuse cutting tools with exchange plate (e.g. with superfinishing edge or Wiper), the cutting edge is made without documenting the basis for optimizing its dimensions. The article presents a generalized edge wear model surrounded by a rounded tip. The proposed solution allows such a modification of edge corner – by determining the conditions of its work – to adapt the tool to stabilize the process of shaping the machined surface.

Corner modes and ground-state degeneracy in models with gaugelike subsystem symmetries

Subsystem symmetries are intermediate between global and gauge symmetries. One can treat these symmetries either like global symmetries that act on subregions of a system, or gauge symmetries that act on the regions transverse to the regions acted upon by the symmetry. We show that this latter interpretation can lead to an understanding of global, topology-dependent features in systems with subsystem symmetries. We demonstrate this with an exactly-solvable lattice model constructed from a 2D system of bosons coupled to a vector field with a 1D subsystem symmetry. The model is shown to host a robust ground state degeneracy that depends on the spatial topology of the underlying manifold, and localized zero energy modes on corners of the system. A continuum field theory description of these phenomena is derived in terms of an anisotropic, modified version of the Abelian K-matrix Chern-Simons field theory. We show that this continuum description can lead to geometric-type effects such as corner states and edge states whose character depends on the orientation of the edge.

Quantum-chemical studies of rutile nanoparticles toxicity I. Defect-free rod-like model clusters

Abstract Using the semiempirical PM6 method, structures of a rod-like [Ti40O124H81]7– model cluster and of [Ti40O124H81Cu]5– with Cu2+ coordinated at various sites were optimized in order to assess the toxicity of rutile nanoparticles. If the relative toxicity of individual Ti centers in rod-like rutile nanoparticles can be evaluated by the electron density transfer to a Cu2+ probe, its maximal values can be ascribed to the pentacoordinated corner and hexacoordinated edge Ti centers with three Ti—OH bonds. However, these centers exhibit the least negative interaction energies which can be compensated by the significantly better accessibility of the corner Ti center compared with that of the remaining ones. Ti centers with the most negative interaction energy parameters exhibit the lowest extent of electron density transfer to a Cu2+ probe. Rutile nanoparticles destruction starts at pentacoordinated Ti face centers.

Investigation on I C Degradation of MgB2 Rutherford Cables by Deformation During Cabling Process

MgB2 superconductors are promising candidates for application to devices such as Superconducting Magnetic Energy Storage, and generators. To apply MgB2 conductors to such devices, the current capacity of a conductor must be in the kilo-ampere range. Meanwhile, because the current capacity of a MgB2 conductor is typically approximately 100 A at 5 T and 4.2 K, multiple stranded cables are required. One candidate is the Rutherford-type cable. During the fabrication of Rutherford cables, strands are deformed by large bending strains at edge corners and indented at flat parts from the pressure of roller dies to maintain the cable shape. It is important to understand how critical current degrades during the fabrication of Rutherford-type cables. To optimize the strand transposition length, three types of Rutherford cables were fabricated and the critical current degradation depending on bending and indented strains was measured. Moreover, to investigate the degradation, inner structures of the strands were observed using micro-focused X-ray computed tomography and an electron probe micro analyzer.

Investigating the spatial development of corrosion of corner-located steel bar in concrete by X-ray computed tomography

In this paper, the chloride-induced corrosion progression of a corner located steel bar in concrete is investigated by X-ray computed tomography (i.e., X-CT). Corrosion of steel bar is accelerated by placing the reinforced specimen in a wetting and drying cyclic corrosive environment, rather than by the impressed current method. 3D X-CT images are obtained and processed to characterize the different material phases, consisting of, steel bar, mortar, corrosion products and voids/cracks. The corrosion products expansion and concrete cracking are analysed and discussed. It has been found that pitting corrosion is prone to appear around the voids close to the steel bar, mainly due to the pre-existing supply of oxygen and moisture. In addition, a distinct transverse crack has been identified which is caused by non-uniform corrosion along the reinforcing steel bar. Within the cross-section, corrosion has also been found non-uniformly distributed, with the maximum rust layer pointing to the corner edge of the sample. Moreover, the corrosion rust distributions are used to parameterize a recently developed non-uniform corrosion model. This experimentally validated non-uniform corrosion model can be applied to corrosion-induced concrete cracking problems with confirmed accuracy. The combination of the use of wetting and drying cyclic corrosive environment and the X-CT scanning can provide a new method to the non-destructive investigation of corrosion process, rust distribution and corrosion-induced concrete cracking in the reinforced concrete structures.

Elastic Higher-Order Topological Insulator with Topologically Protected Corner States.

Topologically gapless edge states, characterized by topological invariants and Berry's phases of bulk energy bands, provide amazing techniques to robustly control the reflectionless propagation of electrons, photons, and phonons. Recently, a new family of topological phases, dictated by the bulk polarization, has been observed, leading to the discovery of the higher-order topological insulators (HOTIs). So far, the HOTIs have been demonstrated in mechanical and electromagnetic systems and electrical circuits with quantized quadrupole polarization and, more recently, have been experimentally realized in optical and acoustic systems. Here, we realize the higher-order topological states in a two-dimensional (2D) continuous elastic system. We experimentally observe the gapped one-dimensional (1D) edge states, the trivially gapped zero-dimensional (0D) corner states, and the topologically protected 0D corner states. Compared with the trivial corner modes, the topological ones, immunizing against defects, are robustly localized at the obtuse-angled but not the acute-angled corners. The topological shape-dependent corner states open a new route for the design of the topologically protected and reconfigurable 0D localized resonances and provide an excellent platform for the topological transformation of the elastic energy among 2D bulk, 1D edge, and 0D corner modes.

A fibre optic wedge type microcavity random laser

In this work, a fibre optic wedge type microcavity with arbitrarily distributed scattering centres is employed to construct a flexible, cost effective, and low threshold random laser. The wedge cavity is constructed within an optical fiber of 125 μm in diameter, using a conventional fibre drawing technique. The sharp edge corners of the triangularly shaped of the air holes are filled with a phenol-rhodamine 6 G mixture via a capillary effect to form the gaining medium. Randomly distributed air-bubbles are naturally formed in different sizes and shapes during the filling process of the phenol-rhodamine mixture, which serve as the scattering centres for obtaining the random lasing. By making a fine spatial tuning of the excitation beam spot towards the apex of the wedge, a single mode lasing is obtained at wavelength of 585 nm, with 1.4 nm of the FWHM.

Analytical modeling of exit Burr in drilling of Ti6Al4V alloy

Burrs affect precision components and cause assembly related problems, and in general, decrease manufacturing productivity. Drilling burr formation involves multiple stages that are influenced by variation in thrust forces, temperature, stress conditions, and deformation modes in the unsupported length of the work-material below the drill. Several of these have not been adequately investigated so far. Therefore, the objective of this work is to model the complex phenomena that occur just before the exit of the drill tip from the bottom surface of the hole, and up to the complete exit of the drill point from the work surface. Accordingly, two models have been developed: (i) to estimate onset of bending in conjunction with theory of plasticity, which leads to the formation of a small drill cap under the pressure of steady-state drilling thrust forces, and (ii) to evaluate exit burr size that involves stretching and bending of a thin layer below the drill tip, using the principle of energy conservation. It is observed that a fracture is initiated at the chisel edge corner resulting in the formation of a small drill cap. The exit burr size predicted by the model is within one standard deviation from the average burr height as determined from the experimental data.

Total curvature (TC) model and its alternating direction method of multipliers algorithm for noise removal

This paper develops a variational model for image noise removal using total curvature (TC), which is a high-order regularizer. The TC has the advantage of preserving image feature. Unfortunately, it also has the characteristics of nonlinear, non-convex and non-smooth. Consequently, the numerical computation with the curvature regularization is difficult. In order to conquer the computation problem, the proposed model is transformed into an alternating optimization problem by importing auxiliary variables. Furthermore, based on alternating direction method of multipliers, we design a fast numerical approximation iterative scheme for proposed model. Finally, numerous experiments are implemented to indicate the advantages of the proposed model in image edge preserving, image contrast and corners preserving. Meanwhile, the high computational efficiency of the designed model is verified by comparing with traditional models, including the total variation (TV) and total Laplace (TL) model.

Salient object detection of fusing foreground seeds and center priori

In this paper, a salient object detection algorithm based on foreground seeds and center priori fusion is proposed. Firstly, using corner detection and edge linking alogrithms obtains two convex hulls, and the approximate position of the target region is preliminarily determined by their intersection points. Then using the convex hull edge as the standard, the similarity of the hyperpixel in the convex hull is detected, and removing superpixels similar to most external edges. Finally, a center priori model fused with the foreground seeds, and the final significant image is obtained by using Bayesian optimization framework. By comparing and merging different visual features, it is shown that this proposed algorithm is very effective in the saliency object detection.

Unevenness of Thin Liquid Layer by Contact Angle Variation of Substrate during Coating Process

During a thin film application, the surface of the coating liquid applied to the substrate becomes uneven because of the geometry of the substrate, viscosity of the coating liquid, surface tension, and its contact angle with the substrate. The surface is particularly uneven at the edge corner portion of the substrate and is thicker than the average coating thickness. This study used the volume-of-fluid (VOF) method to examine the surface unevenness of the coating liquid in terms of the contact angle of the substrate surface and sides. After the coating liquid was evenly applied to the substrate, the maximum height of the uneven region of the coating liquid at the edge of the substrate increased as time passed. The point of maximum height moved away from the edge corner portion of the substrate. The coating liquid applied to the substrate with a contact angle less than 90° exhibited a pinning effect in which the contact point was fixed at the edge. The surface unevenness was more pronounced in the absence of the pinning effect than in its presence, due to the effects of the viscosity of the coating fluid and the surface energy of the substrate.

A thermomechanical analysis leading to a novel flank face design providing longer tool lives for tools used in the drilling of Inconel 718

Inconel 718 is a versatile material due to its excellent properties. However, machining and in particular drilling of Inconel 718 present great challenges for the tools. In order to increase process reliability and tool life, a novel modification for the applied drilling tools was developed. It consists of a flank face retraction behind the cutting edge which is created by grinding. While regular drilling tools feature a continuous flank face on the tool tip, the retraction provides a minimized frictional surface between the tool tip and the bore hole ground. Furthermore, computational fluid dynamics simulations have shown that the created vacuous volume behind the cutting edge becomes filled with cutting fluid during the drilling process. The described effects result in longer tool lives which could be shown in experimental investigations. This paper presents the conducted experiments in which both the occurring mechanical and thermal loads were examined in order to determine the radius-dependent thermomechanical loads along the cutting edge. The results have shown that an increase in either cutting speed or feed result in significantly higher temperatures at the cutting edge corners while temperatures at the inner diameter of the tool remained almost constant. At the same time, a rise in feed leads to notably higher mechanical loads along the whole cutting edge. In addition, reference tool life tests were conducted using standard tools and under variation of the cutting values. The resulting tool wear as well as the tool-workpiece contact zones were investigated in detail. The gathered findings were then used to develop a flank face modification whose sufficient thermomechanical stability was ensured by FEM simulations. Afterwards, the new tool design was applied to drilling tools and then validated in field tests. The results show that a considerably higher drilling distance as well as lower tool wear and thus a longer tool life could be achieved with the modified drills.

(Plenary) NMR and PDF Studies of Local Structure and Dynamics: Applications to Lithium and Sodium Ion Batteries

This talk will focus on method developments to understand structure and dynamics in Li, Na and Mg batteries using a series of local structural probes. Recent studies to improve our understanding of hard carbons for Na-ion batteries will be discussed using both NMR and pair distribution function (PDF) analysis. Here we use both methods to correlate structure with the capacity observed in both the sloping and flat, low voltage component of the electrochemical curve. NMR studies to study dynamics in lithium-ion cathode and anode materials will be discussed. For example, a series of high rate Nb-oxide electrodes and the structures that allow high Li transport and extremely high rates even when micrometer-sized will be described. These structures adopt crystallographic shear and bronze-like structures, and retain open diffusional channels for Li over a wide range of lithium compositions. In part, this is due to structural motifs present in, for example, the shear structures that prevent rotation of the perovskite corner edge sharing octahedra that clamp the Li in place in ReO3-type structures. Their lithium-ion diffusion coefficients (D Li) were measured with pulsed field gradient NMR spectroscopy and have room temperature values that are several orders-of-magnitude faster than typical electrode materials.

Edge effect in the oxidation of three-dimensional nano-structured silicon

Understanding and controlling the oxidation of 3D nano-structured Si is important for the three-dimensional (3D) nano-structured vertical metal–oxide–semiconductor (MOS) field-effect transistor. The retarded oxidation of Si in a corner (edge) has been widely considered since the 1980s to be due to the compressive stress from oxide and/or the slow diffusion of the oxidant in the oxide caused by compressive stress, although some problems remain unresolved. In the current work, a sharp angle in a simultaneously oxidized concave-structured adjacent two-dimensional planar surface was observed for the first time by using transmission electron microscope, for which the traditional consideration is difficult to interpret. We also found that the oxidation of Si near the edge is delayed (edge effect) irrespective of whether the edge is non-oxidized Si3N4 or a simultaneously oxidized convex- or concave-structured adjacent two-dimensional planar surface, widely exists in different Si planar surface of the observed 3D nano-structures (pillar, fin, and terrace) independent of grain orientation. We further developed a model for the formation of the edge effect and discussed its mechanism. The edge effect completely explains the residual Si and formed SiO2 in all Si nano-structures and also contributes in intrinsically understanding and precisely controlling the oxidation of 3D nano-structured Si for future device fabrications.

Hybrid minutiae and edge corners feature points for increased fingerprint recognition performance

In general, most fingerprint recognition systems are based on the minutiae feature points. When matching two fingerprint images, the goal in most recognition systems is to find the optimal transformation model that aligns their feature points in order to find among them the number of matched or aligned points and then generate a matching score. A major problem in feature extraction stage is that when the fingerprint image is of a poor quality due to skin conditions and sensor noise, that leads to many broken ridges in the image caused by cutline. In this case, the extraction of minutiae leads to a lot of spurious points and the performance of the system will degrade. Usually, image enhancement techniques are applied as preprocessing step to overcome this problem. In this work, we propose to use corner points on fingerprint ridges as new features in addition to the ridges minutiae in order to improve the recognition performance. Every ridge is decomposed into several straight edges (SEs). A straight edge is defined as a straight link of ridge points. On a ridge, the head of the first straight edge and the tail of the last one are two minutia and the intersections of the SEs are the ridge corners. Thus, we propose to use a ridge as primitive rather than individual points for matching. This primitive is a structure consisting of groups of both feature points which are minutiae and corners belonging to the same ridge. Based on this primitive, an intelligent matching technique is introduced using sets of feature points on the same primitive. As a result, the recognition performance is increased since it is based on ridge primitive matching rather than individual minutiae matching. Finally, our experimental results compared with those obtained by other well-known techniques in the literature demonstrate the effectiveness and efficiency of our proposed algorithm.