Edge Profile Research Articles

Growth kinetics of a single-walled carbon nanotube: Exact and simulation results

The single walled (SW) carbon nanotube (CNT), discovered in 1991, is a fascinating system for studying key processes relevant to nanomaterials synthesis. It has crucial technological applications, in particular in biomedecine, sensors and telecom networks. In this work, we study numerically the growth kinetics and surface roughness of a hexagonal SWCNT with zero chiral angle using Glauber dynamics. The SWCNT growth kinetics are described in terms of Markov processes whose states are given by its upper edge profile that we mapped onto a 5-vertex model. The model parameters considered are the supersaturation of the fluid phase or driving force and the temperature. The kinetic equation of the system is solved exactly by means of the transition matrix method for small samples and the steady state growth velocity is calculated. Kinetic Monte Carlo (KMC) simulations based on the Bortz–Kalos–Lebowitz (BKL) update algorithm are used to extract some large scale properties of the model.

Revisiting lithic edge characterization with microCT: multiscale study of edge curvature, re-entrant features, and profile geometry on Olduvai Gorge quartzite flakes

The angle and shape of lithic tool edges have long been used as a method of inferring prehistoric tool function. However, accurately measuring and characterizing edge angles of lithic tools is notoriously difficult. Studies using goniometers, calipers, or morphometrics often rely on two-dimensional representations of edges. Furthermore, there have been limited attempts to quantitatively document stone tool edges based on surface metrology, most notably edge curvature. In this study, we use microCT to capture models of the complex geometry, or ‘freeform’ surfaces, of experimental quartzite flakes from Olduvai Gorge (Tanzania) to document and mathematically calculate edge curvature using multiscalar length-scale analysis. Through this analysis, we also explore the quantification of re-entrant (overhang) features on lithic edge cross-sections. On lithic tools, especially coarse-grained rocks with complex surface topographies, such as quartzite, traditional techniques for edge angle measurement are incapable of capturing re-entrant features on edge profiles. Here we present the first archaeological study that addresses the measurement of these re-entrant features, using novel length-scale and curvature analysis methods of calculating edge angles for complex freeform surfaces. With these new methods for measuring edge angles, we can consider the impact of complex geometry, including re-entrant features, on the function of lithic tools in the past.

Analytical model for predicting tool wear in orthogonal machining of unidirectional carbon fibre reinforced polymer (CFRP)

Progressive tool wear due to abrasive carbon fibres is one of the main issues in machining of CFRP and responsible for the short tool life. Because of occurring wear during machining, the tool’s micro-geometry changes continuously resulting in higher process forces and an increasing risk for workpiece damages. In this paper, a novel analytical model is presented in order to predict the wear-related change of the micro-geometry in orthogonal machining of CFRP depending on the fibre orientation and the initial tool geometry. For this purpose, a concept called the wear rate distribution is introduced which represents a measure to quantify the wear rate along the active micro-geometry. Based on experimental investigation, it is shown that the shape of an arbitrary wear rate distribution between two closely spaced wear states can be approximated and parameterised with a “line - curve - line” approach. Using the authors’ previously published analytical force model, the wear rate distribution can be calculated as function of five wear parameters that are used to parameterise the active micro-geometry of an arbitrary wear state. Based on an iterative solver, this is used to simulate the tool wear progression during machining. For model validation, the simulation is compared to experimental data in terms of the cutting edge profiles, the amount of worn tool material and the process forces. Accordingly, the wear model is capable to reproduce the most important wear characteristics, e.g. the cutting edge rounding, the decreasing clearance angle and the increasing contact length at the flank face.

Accuracy and precision of an edge-based modulation transfer function measurement method using a variable oversampling ratio

The edge-based method standardized in ISO 12233 approximates the modulation transfer function (MTF) as a function of horizontal or vertical spatial frequency by analyzing a supersampled edge profile obtained from the captured image of a slightly slanted bi-tonal edge. The method describes the slanted projection of pixels sampled in a square array into a linear array of subpixel-wide bins. An ad hoc correction is available to accommodate the diagonal MTF measurements. However, using a fixed oversampling ratio in the standard method degrades the accuracy and precision of the MTF estimates, owing to the periodic misalignment between the projection paths and the bin array. A new edge-based method using a variable oversampling ratio, OMNI-sine, has been proposed to remedy this misalignment. In this study, computer simulations were performed to demonstrate the accuracy and precision of the MTF estimates over a full range of finely sampled slant angles.

Robust Deep 3D Blood Vessel Segmentation Using Structural Priors.

Deep learning has enabled significant improvements in the accuracy of 3D blood vessel segmentation. Open challenges remain in scenarios where labeled 3D segmentation maps for training are severely limited, as is often the case in practice, and in ensuring robustness to noise. Inspired by the observation that 3D vessel structures project onto 2D image slices with informative and unique edge profiles, we propose a novel deep 3D vessel segmentation network guided by edge profiles. Our network architecture comprises a shared encoder and two decoders that learn segmentation maps and edge profiles jointly. 3D context is mined in both the segmentation and edge prediction branches by employing bidirectional convolutional long-short term memory (BCLSTM) modules. 3D features from the two branches are concatenated to facilitate learning of the segmentation map. As a key contribution, we introduce new regularization terms that: a) capture the local homogeneity of 3D blood vessel volumes in the presence of biomarkers; and b) ensure performance robustness to domain-specific noise by suppressing false positive responses. Experiments on benchmark datasets with ground truth labels reveal that the proposed approach outperforms state-of-the-art techniques on standard measures such as DICE overlap and mean Intersection-over-Union. The performance gains of our method are even more pronounced when training is limited. Furthermore, the computational cost of our network inference is among the lowest compared with state-of-the-art.

The edge profile of liquid spills

The Young–Laplace (Y–L) equation relates the curvature of the interface between two fluids to the pressure difference across that interface. The link between the surface curvature and pressure discontinuity underpins numerous phenomena in hydrostatics, including the profiles of sessile (immobile) drops, pendant drops, capillary bridges, and liquid pearls. In most cases, the application of the Y–L equation readily yields the governing differential equations of the fluid surface but often these equations have no analytic solutions; this is the case, for example, with the profile of a dew drop or a liquid pendant. There are, however, some cases for which the differential equations have closed form solutions; one is the edge profile of a liquid spill or puddle on a horizontal surface. Here, we review the Y–L equation and apply it to obtain the governing differential equations of the edge profile for a liquid spill. The solution of the differential equations results in a universal function that describes the edge profile of any fluid. One important finding is that the profile curve begins its descent very gradually from the flat top of the fluid far away from the edge and terminates at the point, where the angle between the profile curve and the horizontal matches the equilibrium contact angle of the liquid on the substrate.

Numerical investigation of aerodynamic performance of leading edge tubercle airfoil at low Reynolds number

Numerical investigation was made to study the aerodynamic characteristics of the Tubercle NACA2412 airfoil is used in the design of aircraft wing and wind turbine blades. In this paper, computational study aimed to observe the aerodynamic characteristics of 3D airfoil NACA 2412 with peak and trough chord length as 100 mm and 80 mm respectively. The co-efficient of pressure performance of NACA2412 airfoil with tubercle leading edge profile blade used to investigate numerically for enhance the aerodynamics performance of Wind turbine. Investigation were made to find pressure distribution over the Tubercle airfoils under various freestream velocity conditions such as 5 m/s, 10 m/s, 15 m/s and 20 m/s with different angle of attacks from −30° to 30° with the step of 5°. The Spalart–Allmaras turbulent model was used to carry out simulations in the ANSYS Fluent software. Therefore, the Coefficient of pressure distribution is calculated at peak and trough of the tubercle airfoil at different operating conditions and results are plotted in the graph. It is observed that pressure distribution varies drastically near the leading edge for all velocities. Analysis for different velocities with a wide range of angle of attacks are discussed and presented with relevant details.

Clinical Pearls in Postoperative LASIK Management

More than 35 million LASIK procedures have been performed worldwide with reported improvement in outcomes and safety.1 With proper preoperative screening and advanced technology, visual outcomes are excellent with a low complication rate. This paper reviews potential LASIK complications and treatment options. The majority of complications are minor and resolve with treatment without any adverse effects on visual acuity or quality of vision. Over the past 30 years, there have been significant advances in excimer laser technology, which include improved nomograms, flying spot lasers to deliver smoother ablations, accurate trackers, larger optical zones, aspheric curves, and customized treatments that reduce not only refractive errors but other optical aberrations of the eye. In North America, femtosecond lasers for creation of the corneal flap have generally replaced mechanical microkeratomes that require a blade. Advances in femtosecond technology have shown predictable flap thickness and the ability to customize the diameter, location, hinge, and edge profile of the LASIK flap. CE Notification: This article is available as a COPE accredited CE course. You may take this course for 1-hour credit. Read the article and take the qualifying test to earn your credit. Click here to Enroll (https://www.crojournal.com/clinical-pearls-in-postoperative-lasik-management)

Electron microscopy analysis of femtosecond laser-assisted capsulotomy before and after lens fragmentation

Studying anterior lens capsule cutting edge profiles from femtosecond laser-assisted capsulotomy procedures performed before and after lens fragmentation. Twenty eyes (10 patients) with age-related cataract underwent femtosecond laser-assisted surgery (FLACS) using the Ziemer Z8 platform. First step of laser surgery was either capsulotomy (group first) or fragmentation (group second). One eye of each patient was assigned randomly, the second eye treated with the different sequence of procedures. After anterior capsule removal, tissue was fixed in cacodylate-buffered solution and cutting-edge profiles were analysed using scanning electron microscopy (SEM). All cases had cataract grade 2 and 3 based on LOCS III grading. SEM analysis showed more smooth edges in the first group, especially in cases with pseudoexfoliation (P = 0.037); more tags and bridges and a significant number of staggered cutting patterns (7 out of 10 cases) in the second group. All cases evolved the same microgroves with “valleys and mountains “ as signs of the photodisruption process. Femtosecond laser capsulotomy should be performed before lens fragmentation minimizing the rate of cutting errors. Especially in eyes with advanced cataract, as intracapsular pressure may increase due to lens fragmentation without anterior capsular opening.

A Comparison of the Probes with a Cantilever Beam and a Double-Sided Beam in the Tool Edge Profiler for On-Machine Measurement of a Precision Cutting Tool

This paper describes a comparison of the mechanical structures (a double-sided beam and a cantilever beam) of a probe in a tool edge profiler for the measurement of a micro-cutting tool. The tool edge profiler consists of a positioning unit having a pair of one-axis DC servo motor stages and a probe unit having a laser displacement sensor and a probe composed of a stylus and a mechanical beam; on-machine measurement of a tool cutting edge can be conducted with a low contact force through measuring the deformation of the probe by the laser displacement sensor while monitoring the tool position. Meanwhile, the mechanical structure of the probe could affect the performance of measurement of the edge profile of a precision cutting tool. In this paper, the measurement principle of the tool edge profile is firstly introduced; after that, slopes and a top-flat of a cutting tool sample are measured by using a cantilever-type probe and a double-sided beam-type probe, respectively. The measurement performances of the two probes are compared through experiments and theoretical measurement uncertainty analysis.

Mathematical Modeling for Ceramic Shape 3D Image Based on Deep Learning Algorithm

Ceramic image shape 3D image modeling focuses on of ceramic that was obtained from the camera imaging equipment such as 2D images, by normalization, gray, filtering denoising, wavelet image sharpening edge enhancement, binarization, and shape contour extraction pretreatment processes such as extraction ceramic image shape edge profile, again, according to the image edge extraction and elliptic rotator ceramics phenomenon. The image distortion effect was optimized by self-application, and then the deep learning modeler was used to model the side edge contour. Finally, the 3D ceramic model of the rotating body was restored according to the intersection and central axis of the extracted contour. By studying the existing segmentation methods based on deep learning, the automatic segmentation of target ceramic image and the effect of target edge refinement and optimization are realized. After extracting and separating the target ceramics from the image, we processed the foreground image of the target into a three-dimensional model. In order to reduce the complexity of the model, a 3D contextual sequencing model is adopted to encode the hidden space features along the channel dimensions, to extract the causal correlation between channels. Each module in the compression framework is optimized by a rate-distortion loss function. The experimental results show that the proposed 3D image modeling method has significant advantages in compression performance compared with the optimal 2D 3D image modeling method based on deep learning, and the experimental results show that the performance of the proposed method is superior to JP3D and HEVC methods, especially at low bit rate points.

Die Bedeutung des Randprofiles bei der Anpassung weicher Kontaktlinsen: ein Update

Purpose. The edge design of soft contact lenses is often overseen during contact lens fitting or during follow­up visits. Material and Methods. By means of illustrations of different edge profiles and a review of the literature on this topic, the attention of contact lens practitioner should be drawn to edge design of contact lenses. Results. Contact lenses have different edge profiles, which can have an influence on comfort and fitting. If necessary,the edge profile can be observed by the contact lens fitter using various methods. Conclusion. Consideration of the edge design can be par­ ticularly helpful for contact lens fittings that do not lead to the desired success. Keywords soft contact lenses, contact lens edge design, contact lens discomfort, conjunctiva

Modeling cutting edge degradation by chipping in micro-milling

The cutting edges of micro-milling tool undergo degradation with time, in the form of continuous abrasion and intermittent chipping. As a result, the cutting tool looses its original profile and consequently affects the quality of molds and dies manufactured using micro-milling process. This work therefore focuses on understanding the physics and mechanism of tool wear in micro-milling as function of tool life, and to model the transient degradation of cutting tool, which was not investigated in-depth in the literature. Extensive micro-milling experiments were done till the end of tool life, to investigate cutting edge degradation. Further, analytical as well as empirical models were developed to predict continuous abrasion interrupted by chipping, and to determine cutting edge profiles as a function of tool life. The abrasion wear model involved modifying Archard’s equation and evaluating tool wear coefficient empirically using a novel pin-on-disk device. The interrupted chipping wear phenomenon during micro-milling was identified by locating sudden drop in resultant forces on the tool. The chipping wear was then modeled using the dimensions of the chipped portions, extracted from the tool images captured in-situ. It was observed from the experiments that the length (C) of the chipped portions of the cutting edges was between 15.76 to 96 μm, whereas, their width (H) was between 7 to 29 μm, and they were found to have a positive correlation. The chipping load estimated from the resultant force, and the load inclination angle evaluated from the chipping model were found to have an inverse correlation, and varied between 1.23 to 3.75 N, and 69 to 25° respectively. The proposed abrasion and chipping wear model jointly gave transient progression of total volumetric tool wear area, and consequent cutting edge profiles over the tool-life cycle. The proposed tool wear model predicted the total wear within 9.3% of the experimental values.

A Two-Round Weight Voting Strategy-Based Ensemble Learning Method for Sea Ice Classification of Sentinel-1 Imagery

Sea ice information in the Arctic region is essential for climatic change monitoring and ship navigation. Although many sea ice classification methods have been put forward, the accuracy and usability of classification systems can still be improved. In this paper, a two-round weight voting strategy-based ensemble learning method is proposed for refining sea ice classification. The proposed method includes three main steps. (1) The preferable features of sea ice are constituted by polarization features (HH, HV, HH/HV) and the top six GLCM-derived texture features via a random forest. (2) The initial classification maps can then be generated by an ensemble learning method, which includes six base classifiers (NB, DT, KNN, LR, ANN, and SVM). The tuned voting weights by a genetic algorithm are employed to obtain the category score matrix and, further, the first coarse classification result. (3) Some pixels may be misclassified due to their corresponding numerically close score value. By introducing an experiential score threshold, each pixel is identified as a fuzzy or an explicit pixel. The fuzzy pixels can then be further rectified based on the local similarity of the neighboring explicit pixels, thereby yielding the final precise classification result. The proposed method was examined on 18 Sentinel-1 EW images, which were captured in the Northeast Passage from November 2019 to April 2020. The experiments show that the proposed method can effectively maintain the edge profile of sea ice and restrain noise from SAR. It is superior to the current mainstream ensemble learning algorithms with the overall accuracy reaching 97%. The main contribution of this study is proposing a superior weight voting strategy in the ensemble learning method for sea ice classification of Sentinel-1 imagery, which is of great significance for guiding secure ship navigation and ice hazard forecasting in winter.

Pressure Fluctuation Reduction of a Centrifugal Pump by Blade Trailing Edge Modification

The pressure fluctuation inside centrifugal pumps is one of the main causes of hydro-induced vibration, especially at the blade-passing frequency and its harmonics. This paper investigates the feature of blade-passing frequency excitation in a low-specific-speed centrifugal pump in the perspective of local Euler head distribution based on CFD analysis. Meanwhile, the relation between local Euler head distribution and pressure fluctuation amplitude is observed and used to explain the mechanism of intensive pressure fluctuation. The impeller blade with ordinary trailing edge profile, which is the prototype impeller in this study, usually induces wake shedding near the impeller outlet, making the energy distribution less uniform. Because of this, the method of reducing pressure fluctuation by means of improving Euler head distribution uniformity by modifying the impeller blade trailing edge profile is proposed. The impeller blade trailing edges are trimmed in different scales, which are marked as model A, B, and C. As a result of trailing edge trimming, the impeller outlet angles at the pressure side of the prototype of model A, B, and C are 21, 18, 15, and 12 degrees, respectively. The differences in Euler head distribution and pressure fluctuation between the model impellers at nominal flow rate are investigated and analyzed. Experimental verification is also conducted to validate the CFD results. The results show that the blade trailing edge profiling on the pressure side can help reduce pressure fluctuation. The uniformity of Euler head circumferential distribution, which is directly related to the intensity of pressure fluctuation, is improved because the impeller blade outlet angle on the pressure side decreases and thus the velocity components are adjusted when the blade trailing edge profile is modified. The results of the investigation demonstrate that blade trailing edge profiling can be used in the vibration reduction of low specific impellers and in the engineering design of centrifugal pumps.

Supersymmetry with scattering states

Supersymmetric partner potentials calculated using single-particle non-reflecting scattering states are localized complex potentials with real eigenvalues. If the initial potential is a symmetric real potential then the partner potential is PT-symmetric. In particular cases, complex conduction band edge profiles are found that yield supersymmetric partner total potentials evaluated using scattering states in the context of self-consistent Schrödinger-Poisson equations.

Blades Optimization for Maximum Power Output of Vertical Axis Wind Turbine

Wind power is a significant and urging sustainable power source asset to petroleum derivatives. Wind machines, for example, H-Darrieus vertical pivot wind turbines (VAWTs) have increased much notoriety in research network throughout the most recent couple of decades because of their applications at destinations having moderately low wind speed. Be that as it may, it is noticed that such wind turbines have low effectiveness. The point of this examination is to plan rotor cutting edges which could create most extreme power yield and execution. Different plan factors, for instance, harmony length, pitch edge, rotor distance across, cutting edge length and pitch point are explored to upgrade the presentation of VAWT. Rotor cutting edges are manufactured using the NACA-0030 structure and tried in wind burrow office and contrast its outcomes and DSM 523 profile. Numerical simulations are performed to get best geometry and stream conduct for achieving greatest power. It is seen that for higher tip-speed-proportion (TSR), shorter harmony length and bigger distance across the rotor (i.e., lower robustness) yields higher effectiveness in NACA 0030. Nevertheless, for lower TSR, the more drawn out agreement length and slighter distance across rotor (i.e., higher strength) gives better implementation. The pitch point is - 2° for TSR = 3 and - 3° for TSR = 2.5. The most extreme power yield of the wind turbine is acquired for the sharp edge profile NACA 0030. Besides, instantaneous control coefficient, power coefficient (CP) is the greatest reason for azimuthal edge of 245° and least esteem for 180°.

Effect of beam quality and readout direction in the edge profile on the modulation transfer function of photostimulable phosphor systems via the edge method.

Purpose: The objective of this study was to investigate the effects of (i) the difference in the beam qualities on the presampled modulation transfer function (MTF) using the edge method and (ii) the readout direction of the edge profile for the photostimulable phosphor (PSP) system. Approach: The International Electrotechnical Commission (IEC) defined a technique using the "radiation qualities based on a phantom made up of an aluminum added filter" (RQA). A general radiographic system with a tube voltage of 50kV and 9.7mm of additional aluminum filtration was used to conform the x-ray to the IEC-specified beam quality definition RQA3. Additionally, we employed two different beams with tube voltages of 60 and 70kV using a dental x-ray unit. The MTF was measured in the readout direction from low-to-high exposure regions and vice versa with respect to the scanning and subscanning directions of the PSP system. Results: The difference in the 50%MTF value for all directions between 60 and 70kV averaged less than . The 50%MTF of RQA3 was on average 0.2 lower than the value for 60kV for each direction. For all beam qualities, no difference was observed between the MTFs measured in the readout direction from the low-to-high exposure regions and vice versa. Conclusions: The MTFs, measured using the dental x-ray unit, were unaffected by the tube voltage, and they were slightly higher than those measured using the RQA3. Furthermore, the MTF was unaffected by the differences in the readout directions of the edge profile.

Wrinkled and wrinkle-free membranes

The extreme out-of-plane flexibility makes membranes vulnerable of wrinkling, which limits the applications with stringent-accuracy demands and high-frequency requirements. In this study, a theoretical analysis is proposed to predict the minimum of min-principal stress min(σmin), representing the wrinkling capability of the stretched membrane with an arbitrary aspect ratio and random curved edges, while the curved edges are represented by a Fourier series function. The Marguerre function is adopted to calculate the stress solutions and the sigma-approximation approach is employed to eliminate the Gibbs phenomenon. The determination of numbers of truncated terms of Marguerre function and the normalization strategy are helpful to solve the ill-posed problem. The accuracy and generality of our analytical solutions are verified by the finite element results. Moreover, the wrinkling criterion indicates that the entire membrane is taut and wrinkle-free if min(σmin) is positive. With maximizing the membrane area as the objective function, the positive min(σmin) as constraint, and the Fourier coefficients tuning edge profiles as design variables, the structural design approach gives the optimal configurations, whose wrinkle-free performance is verified by the finite element analyses and physical experiments.

Fabrication of a silicon μDicer for uniform microdissection of tissue samples

Generating uniform tissue microfragments is important in many applications, including disease diagnostics, drug screening, spatial-omics, and fundamental wound healing and tissue regeneration studies. Common mechanical dissection methods, such as manual mincing, are imprecise and result in fragments with a broad range in size. This work aims to develop a microscale dicing device, referred to as the “μDicer,” consisting of a hollow array of blades spaced hundreds of micrometers apart. A tissue pushed through this array is diced into many microfragments simultaneously. The focus of this paper is on the fabrication process of the μDicer using a combination of isotropic and anisotropic etching in silicon. A single silicon oxide etch mask is used in a dry silicon etcher for both a tapered etch to form the microblades, and an anisotropic etch to form the through-holes in the hollow blade array. The use of a single mask reduces the mask fabrication time by more than twofold compared with two-mask approaches often used to generate similar etch features. The etch parameters and the design of the etch mask control the blade angles and the edge profiles of the blades. Specifically, the incorporation of “notches” in the two-dimensional mask design generates three-dimensional microserrated features on the blade edges. A custom, open-source etching model is also developed to facilitate the prediction of the etch profiles. Finally, a proof-of-concept application of the μDicer to dissect soft materials and tissues is demonstrated.