Edge Cross Research Articles

Pronator quadratus musculo-osseous free flap for wide hard palatal defect reconstruction: An anatomical study

Wide hard palate defects include congenital and acquired defects that are six square centimeters or larger in size. Obturator prostheses and autologous soft tissue transfers have been used to reconstruct palatal defects. This study aims to repair wide, hard palatal defects by using a pronator quadratus musculo-osseous free flap to achieve subtotal reconstruction. Seventeen formalin-fixed cadavers were dissected. Free musculo-osseous pronator quadratus flaps were prepared after a 12 cm curvilinear volar skin incision. Standard 30 × 23 mm (690 ± 52.12 mm2) hard palate defects were made by chisels and saws. A subcutaneous tunnel was created between the mandibular edge cross point of the facial vessels and the retromolar trigone through the subcutaneous to the superficial musculoaponeurotic system by dissection. Area measurements of the pedicle and palate defects were performed by the ImageJ program (National Institutes of Health, Bethesda, MD, USA) on drawings over an acetate layer of materials. Mandibular distances of gonion-facial vessel cross point (a), gonion-gnathion (m), and facial vessels’ cross point-retromolar entrance point (h) were measured. Ratios of h/m and a/m were calculated. The mean pronator quadratus area was 2349.39 ± 444.05 mm2, and the arterial pedicle pronator quadratus diameter was 2.32 ± 0.34 mm. The mean pedicle length of the pronator quadratus was 117.13 ± 8.10 mm. Study results showed that musculo-osseous pronator quadratus flaps’ bone and muscle parts perfectly fit on the defects in all cadavers. Pronator quadratus musculo-osseous flap is a feasible surgical option for wide, hard palatal defect reconstruction strategies.

The Surviving Rate of IC-Planar Graphs

Let k and n be two positive integers. Firefighting is a discrete dynamical process of preventing the spread of fire. Let G be a connected graph G with n vertices. Assuming a fire starts at one of the vertices of G, the firefighters choose k unburned vertices at each step, and then the fire spreads to all unprotected neighbors of the burning vertices. The process continues until the fire stops spreading. The goal is to protect as many vertices as possible. When a fire breaks out randomly at a vertex of G, its k-surviving rate, ρk(G), is the expected number of saved vertices. A graph is IC-planar if it has a drawing in which each edge cross once and their endpoints are disjoint. In this paper, we prove that ρ4(G)>1124 for every IC-planar graph G. This is proven by the discharging method and the locally symmetric of the graph.

Currents and Cross-Currents on the Black and African Theology Landscape Today: A Thematic Survey

ABSTRACT This article attempts to lift up the salient, latest most cutting edge currents and cross currents in black and Africantheologies on the continent and in the diaspora. As well as proposing an analytical framework, the article articulates the key challengesfacing black and African theologies today.

Performance and wear mechanisms of uncoated, TiAlN, and AlTiN-coated carbide tools in high-speed drilling of Al-Si alloy

Owning to the extremely abrasive silicon particles, low melting point of aluminum, and its susceptibility to adhere to the tool, high-speed drilling of aluminum alloys containing high silicon content becomes a challenging operation. Hence, the understanding of the tool wear mechanisms is essential in order to develop and select the efficient tool material. This paper reports on the investigation of performance and wear mechanism of uncoated and TiAlN and AlTiN-coated tools when high-speed drilling of Al-Si (A383) alloy. Drilling tests were conducted at various cutting parameters, while thrust forces were measured using a dynamometer. The wear mechanisms that contributed to the drill failure were assessed by analyzing the worn cutting edge and drill bit cross section; and by employing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Results showed that feed rate has the highest effect on the primary wear stage; and flank wear at the outer cutting edge found to be dominant failure mode for all tools. Moreover, it is found that plastic deformation, diffusion, attrition, abrasion, and fracture are the main operating tool wear mechanisms. The longest tool life was recorded for AlTiN-coated tool, but more adhesion of Al was observed on this tool surface. At the end, TiAlN-coated drill was proposed as the tool with the best performance among the tool materials used in this study.

3D multiscale curvature analysis of tool edges as an indicator of cereal harvesting intensity

The adoption of an agricultural lifeway is considered one of the most significant cultural events in prehistory. Microwear analysis of stone harvesting tools is among the many approaches used to document the transition to agriculture in the Near East. Traditionally, these microwear analyses rely on the use of optical microscopy and visual-verbal descriptions of wear criteria. In addition to traditional optical microscopy, ongoing research into the applications of surface metrology for the characterization of microwear traces has contributed to the development of quantitative microwear methods. Despite significant research into the quantification of lithic microwear polishes, there has been comparatively little research on the quantification of tool edge angles to understand function. In this paper, we test a new method for the quantification of areal curvature of stone harvesting tool edges at multiple scales using data collected with focus variation microscopy. These calculations are based on curvature tensors of the measured surface topographies along tool edge cross sections. This method allows calculation of maximal and minimal curvatures at each location and scale. For this paper, we analyze a set of experimental microliths used as cereal harvesting tools using changes in multiscalar areal edge curvature to mathematically document harvesting intensity (duration of use). This experimental research presents a new method for documenting used stone tool edges that will contribute to our understanding of how harvesting tools were used, curated, and discarded in the past, giving insight into the food collection practices of early farmers.

ТОЧНОЕ РЕШЕНИЕ ЗАДАЧИ О НАГРУЖЕНИИ ДАВЛЕНИЯМИ ПОЛОГО ЦИЛИНДРА ИЗ НЕЛИНЕЙНО НАСЛЕДСТВЕННОГО МАТЕРИАЛА В СЛУЧАЕ СТЕПЕННЫХ ФУНКЦИЙ НЕЛИНЕЙНОСТИ

We study analytically the exact solution of the quasi-static problem for a thick-walled tube of physically non-linear viscoelastic material obeying the Rabotnov constitutive equation with two arbitrary material functions (a creep compliance and a function which governs physical non-linearity). We suppose that a material is homogeneous, isotropic and incompressible and that a tube is loaded with time-dependent internal and external pressures (varying slowly enough to neglect inertia terms in the equilibrium equations) and that a plain strain state is realized, i.e. zero axial displacements are given on the edge cross sections of the tube. We previously have obtained the closed form expressions for displacement, strain and stress fields via the single unknown function of time and integral operators involving this function, two arbitrary material functions of the constitutive relation, preset pressure values and radii of the tube and derive functional equation to determine this unknown resolving function. Assuming creep complience is arbitrary and choosing the material function governing non-linearity to be power function with a positive exponent, we construct exact solution of the resolving non-linear functional equation, calculate all the convolution integrals involved in the general representation for strain and stress fields and reduce it to simple algebraic formulas convenient for analysis and use. Strains evolution in time is characterized by creep compliance function and loading history. The stresses in this case depend on the current magnitudes of pressures only, they don't depend on creep compliance (i.e. viscoelastic properties of a material) and on loading history. The stress field coincides with classical solution for non-linear elastic material or elastoplastic material with power hardening (for non-decreasing pressure difference). We obtain criteria for increase, decrease or constancy of stresses with respect to radial coordinate in form of inequalities for the exponent value and for difference of pressures. Assuming creep compliance is arbitrary, we study analytically properties of strain and stress fields in a tube under internal pressure growing with constant rate and properties of corresponding stress-strain curves implying measurement of strains at a surface point of a tubular specimen.

Low dose CBCT reconstruction via prior contour based total variation (PCTV) regularization: a feasibility study

Purpose: compressed sensing reconstruction using total variation (TV) tends to over-smooth the edge information by uniformly penalizing the image gradient. The goal of this study is to develop a novel prior contour based TV (PCTV) method to enhance the edge information in compressed sensing reconstruction for CBCT.Methods: the edge information is extracted from prior planning-CT via edge detection. Prior CT is first registered with on-board CBCT reconstructed with TV method through rigid or deformable registration. The edge contours in prior-CT is then mapped to CBCT and used as the weight map for TV regularization to enhance edge information in CBCT reconstruction. The PCTV method was evaluated using extended-cardiac-torso (XCAT) phantom, physical CatPhan phantom and brain patient data. Results were compared with both TV and edge preserving TV (EPTV) methods which are commonly used for limited projection CBCT reconstruction. Relative error was used to calculate pixel value difference and edge cross correlation was defined as the similarity of edge information between reconstructed images and ground truth in the quantitative evaluation.Results: compared to TV and EPTV, PCTV enhanced the edge information of bone, lung vessels and tumor in XCAT reconstruction and complex bony structures in brain patient CBCT. In XCAT study using 45 half-fan CBCT projections, compared with ground truth, relative errors were 1.5%, 0.7% and 0.3% and edge cross correlations were 0.66, 0.72 and 0.78 for TV, EPTV and PCTV, respectively. PCTV is more robust to the projection number reduction. Edge enhancement was reduced slightly with noisy projections but PCTV was still superior to other methods. PCTV can maintain resolution while reducing the noise in the low mAs CatPhan reconstruction. Low contrast edges were preserved better with PCTV compared with TV and EPTV.Conclusion: PCTV preserved edge information as well as reduced streak artifacts and noise in low dose CBCT reconstruction. PCTV is superior to TV and EPTV methods in edge enhancement, which can potentially improve the localization accuracy in radiation therapy.

Observations of the effects of magnetic topology on the SOL characteristics of an electromagnetic coherent mode in the first experimental campaign of W7-X

Turbulence is considered to play an important role in the edge cross field heat and particle transport in fusion devices. Scrape-off layer (SOL) turbulence characteristics were measured by the combined probe mounted on the multi-purpose manipulator during the first experimental campaign of W7-X. An electromagnetic coherent mode (EMCM) at 7 kHz has been observed by multiple diagnostics in both the plasma core and the SOL and exhibits a strong dependence of the magnetic topology. As demonstrated by the measurements of the combined probe, the EMCM starts to appear at a radius of R = 6.15 m along the path of probe measurement and this location is shifted inwards in higher iota configurations. It propagates along the direction of electron diamagnetic drift in the far SOL with a poloidal velocity about 0.6 km s−1 while it turns to the opposite direction gradually in the near SOL in the laboratory frame, but keeps a velocity of about 0.6–0.7 km s−1 along the direction of electron diamagnetic drift in the plasma frame. This mode can be induced by raising the ECRH heating power in similar discharge conditions, which is probably linked to the gradient of electron temperature and pressure. The EMCM is enhanced significantly in the edge magnetic island with long connection length where the EMCM can grow up due to the long particle confinement time.

Research on Fault Detection System of Power Equipment Based on UV and Infrared Image

UV corona on power system can reflect the location of the fault and the severity of the fault, the traditional UV and infrared detection equipment can only use the band and the visible light band image of the power system fault detection. In this paper, a power system fault detection system based on ultraviolet and infrared dual-band images is designed. The principle of UV imaging detection and image fusion are introduced respectively. The software of the host computer is written by MFC. The software can acquire both ultraviolet and infrared, the two images are fused using the image fusion algorithm based on edge detection and cross correlation and the highest point temperature is plotted. Experiments show that the system can detect the failure of power equipment in time, and has a certain practical value, which puts forward a new idea for fault detection of power equipment.

Characterization of the cleaved edge cross section of the heterostructures with GaMnAs layer by the confocal micro-Raman spectroscopy

Confocal micro-Raman spectroscopy was used to measure cross-section linescans of the cleaved edge of heterostructures involving a GaMnAs layer. The investigations revealed a shift of the TO mode in the compressed GaMnAs layer to high frequencies relative to the TO GaAs mode in the substrate and to low frequencies in the tensile GaMnAs layers. These results are in agreement with the different manifestations of the anomalous Hall effect in the GaMnAs layers, with either compressive or tensile strains. It is shown that Raman spectroscopy is an appropriate method for the investigation of cross-sectional semiconductor heterostructures whose total thickness is comparable to the size of the analyzing laser spot.

Influence of corrugated boundary hydrodynamics on the swimming performance and behaviour of juvenile common carp (Cyprinus carpio)

To facilitate the upstream passage of small fish, corrugated culverts are often preferred over smooth pipes, due to the lower edge and mean cross sectional water velocities created. This benefit could be lost if greater intensities of turbulence induced by wall roughness cause instability and increase the energetic expense of fish locomotion. Common carp (Cyprinus carpio) swimming performance and behaviour were evaluated in a flume using four wall roughness treatments: smooth (control), small (SC), medium (MC), and large (LC) corrugations, dependent on corrugation wavelength and amplitude. Individual fish (n=128, mean±S.D. total length [TL]=86±8mm) swam at a mid-channel velocity of 0.5ms−1 for 30min or until fatigue. Swimming performance was quantified by: (a) success (completion of 30min trial) or failure; and (b) the time to fatigue (endurance) of those that failed. To evaluate behaviour, fish head positions were tracked manually every second. Occupancy of the area within the MC and LC troughs (concave area where velocity was lowest) was recorded and the relationships between trough occupation and (i) TL and (ii) success tested. Differences were tested for between successful and failed individuals, and among treatments, for the following dependent variables: the total distance moved, the mean distance from the flume wall occupied (FishD), and mean velocity (FishU) and turbulent kinetic energy (FishTKE) experienced. Treatment did not influence frequency of success (38–58% per treatment) or time to fatigue. During the MC and LC treatments, troughs were occupied for part of the trial by 56 and 55% of individuals, respectively. Trough occupation was independent of TL in both treatments, and more common for successful fish than failures in the LC treatment. For successful fish, the total distance moved did not differ among treatments. Successful FishD varied among treatments and was higher for the LC (mean±S.E.=93.2±22.3mm) than the SC (33.5±2.8mm) treatment. Despite the availability of lower velocity areas, median successful FishU was higher in the LC treatment (0.51ms−1) than in any other (median=0.47ms−1, 0.44ms−1 and 0.47ms−1 in the MC, SC, and control treatments, respectively). Treatment did not influence successful FishTKE which was consistently low (median=5.3–7.7Jm−3 per treatment). Although occupation of the MC and LC troughs occurred, many individuals spent little time here, and areas with lower TKE were often occupied. Under the experimental conditions created, this study does not support the assumption that low velocity areas created by wall corrugations will improve culvert passage.

Effects of F− on the optical and spectroscopic properties of Yb3+/Al3+-co-doped silica glass

Yb3+/Al3+-co-doped silica glasses with different F− content were prepared in this work by sol–gel method combined with high temperature sintering. XRF, FTIR and XPS methods were used to confirm the presence of F−. The effects of F− on the optical and spectroscopic properties of these glasses have been investigated. It is worth to notice that the F−/Si4+ mass ratio equal to 9% is a significant value showing a real change in the variation trends of numerous following parameters: refractive index, UV absorption edge, absorption and emission cross sections, scalar crystal-field NJ and fluorescent lifetimes. Furthermore, introduction of F− can adjust the refractive index of Yb3+/Al3+-co-doped silica glass and it is useful for large mode area (LMA) fibers.

The Anti-Plane Shear Problem of Two Symmetric Cracks Originating from an Elliptical Hole in 1D Hexagonal Piezoelectric QCs

Using the complex variable function method and the technique of conformal mapping, the fracture mechanics of two symmetric collinear cracks originating from an elliptical hole in a one-dimensional (1D) hexagonal piezoelectric quasicrystals (QCs) are investigated under anti-plane shear loading and electric loading. The crack is assumed to be either electrical impermeable or permeable. The exact solutions in closed-form of the stress intensity factors (SIFs) of the phonon field and the phason field, and the electric displacement intensity factors (EDIFs) are obtained. In the limiting cases, the new results such as Griffith crack, a circular hole with equal two edge cracks and cross crack can be obtained from the present solutions. In the absence of the phason field, the obtainable results in this paper match with the classical results.

Photocapacitance Decay Technique for Interface Trap Characterization Near Inversion Band in Wide Bandgap MOS Capacitors

A technique to characterize interface traps near the minority carrier band for wide bandgap metal-oxide-semiconductor (MOS) capacitors at room temperature is presented. The method uses photogeneration of minority carriers and transient analysis of the subsequent photocapacitance decay to evaluate trap response times. The technique is demonstrated using n-type substrate 6H- SiC/SiO2 MOS capacitors to extract interface trap density (Dit) ranging in energy from 0.2 to 0.8 eV above the valence band edge (Ev) and trap cross sections from 0.4 to 0.7 eV above Ev. For the given material system, traps near Ev exhibit significant differences between n-and p-type substrate MOS capacitors.

Analyse and Control Research about the Cause of Shape Defects on Hot-Rolled Strip Steel

Strip shape defects, especially the crown problem, once appeared in the production of hot-rolled strip steel in SG Company. The macroscopic characteristic is the thickness difference occurred between the center and edge cross section of hot-rolled plate. Morphological characteristics and forming reasons can be got by analyzing roll wear. Research shows that the main reason for the formation of crown is excessive attrition of work roll in later period, which leading to smaller roll shape. Therefore, shape defects have been effectively controlled after introducing CVC roll contour technology to optimize roll shape. Quality qualified rate of strip shape of hot-rolled strip steel is more than 99.6% percent, and it has been successfully put into application of hot rolling mill.

Atomic Structure of Interconnected Few-Layer Graphene Domains

The atomic structure at the boundary interface between interconnected few-layer graphene (FLG) domains, synthesized by atmospheric pressure chemical vapor deposition (AP-CVD), is examined using aberration-corrected high-resolution transmission electron microscopy. Moiré patterns in the HRTEM images reveal the presence of rotational stacking faults in the boundary region that extend over distances of ∼100 nm. We show that FLG domains interconnect via two principle processes: graphene sheets from one domain grow over the top of a neighboring domain, while other graphene domains interconnect by direct atomic bonding. Differentiating between these two types of interconnects was found to be possible by examining the HRTEM contrast profiles produced at the interface. Graphene sheets that terminate were found to produce strong edge contrast with increasing defocus values, as well as a broader edge cross section, whereas atomically bonded interfaces were found to not exhibit any contrast, even under large defocus values. These findings are reinforced by correlating with multi-slice TEM image simulations of appropriate structures.

Singularities of spacelike constant mean curvature surfaces in Lorentz–Minkowski space

AbstractWe study singularities of spacelike, constant (non-zero) mean curvature (CMC) surfaces in the Lorentz–Minkowski 3-space L3. We show how to solve the singular Björling problem for such surfaces, which is stated as follows: given a real analytic null-curve f0(x), and a real analytic null vector field v(x) parallel to the tangent field of f0, find a conformally parameterized (generalized) CMC H surface in L3 which contains this curve as a singular set and such that the partial derivatives fx and fy are given by df0/dx and v along the curve. Within the class of generalized surfaces considered, the solution is unique and we give a formula for the generalized Weierstrass data for this surface. This gives a framework for studying the singularities of non-maximal CMC surfaces in L3. We use this to find the Björling data – and holomorphic potentials – which characterize cuspidal edge, swallowtail and cuspidal cross cap singularities.

Deformation Microstructure in (001) Single Crystal Strontium Titanate by Vickers Indentation

Recent interests on the plastic deformation of strontium titanate (SrTiO3) are derived from its unusual ductile‐to‐brittle‐to‐ductile transition (DBDT). The transition is divided into three regimes (A, B, and C) corresponding to the temperature range of 113–1053 K (−160° to 780°C), 1053 to ∼1503 K (780° to ∼1230°C), and ∼1503–1873 K (∼1230° to 1600°C), discovered by Sigle and colleagues in the MPI‐Stuttgart. We report the dislocation substructures in (001) single crystal SrTiO3 deformed by Vickers indentation at room temperature, studied by scanning and transmission electron microscopy. Dislocation dipoles of screw and edge character are observed and confirmed by inside–outside contrast using ±g‐vector by weak‐beam dark field imaging. They are formed by edge trapping, jog dragging, and cross slip pinching‐off. Similar to dipole breaking off in deformed sapphire (α‐Al2O3) at 1200°C and γ‐TiAl intermetallic at room temperature, the dipoles pinch off at one end, and emit a string of loops at trail. Two sets of slip systems {110}〈 〉 and {100}〈011〉 are activated under both 100 g and 1 kg load. The suggestion is that plastic deformation has reached the stage II work hardening, which is characterized by multiplication of dislocations through cross slip, interactions between dislocations, and operating of multiple slip systems.

On noise reduction by flap side edge fences

This paper discusses the effects of fences on side edge cross flows. Experimental data are reviewed to show that fences can modify the cross flow in the side edge region of aircraft flaps in such a way that noise reduction can be achieved. Near field pressure data reveal that fences reduce the characteristic frequency of the flow fluctuations. This leads us to postulate that the fences make the far field noise spectra shift downward in frequency. Because airframe noise spectra typically have a negative slope in the most important mid to high frequency domain, this downward shift in frequency leads to an equivalent reduction of noise levels, when measured by conventional metric such as the effective perceived noise level in aircraft certification. To explain the decrease of the characteristic frequency of the flow fluctuations due to the fences, an analytical model is developed, based on vortex dynamics. The predictions from the model are shown to be in very good agreement with measured data, both for the dominant frequency in the baseline case without the fences and for the trends of the decreasing frequency with increasing fence height.

Comparison of in situ optical reflectance and post-growth characterisation for quantitative composition and thickness determination of Al xGa 1- xAs

We assess the use of normal incidence in situ laser reflectometry (LR) to give reliable quantitative composition and thickness information during epitaxial growth of a full range of Al x Ga 1- x As (0.1⩽ x⩽0.9) alloys on GaAs. It is shown that, provided the optical constants ( n and k) are known accurately at the growth temperature, LR gives accurate results for both layer thickness and composition. Post-growth layer thickness measurements on cleaved edge cross section and wedge section TEM samples are more accurate than LR, but LR gives a much more accurate determination of composition than energy dispersive X-ray analysis on cross-sectional TEM samples and from thickness fringe analysis on wedge TEM samples. The relative advantages of LR and post-growth analysis are discussed.