Edge Width Research Articles

The Research and Experiments on Contact Sealing Theory of the Underwater Clamp Connector

With regard to the sealing structure characteristics of the underwater clamp connector, based on the Hertz contact theory, this article studies the method of solving the extreme value of the radius of curvature on the two curved surfaces at the sealing contact point; first, the method of calculating the extreme value of the radius of curvature at any surface point of the rotary part is obtained, and then the equivalent radius of curvature is solved. Using finite element simulation to study the contact sealing characteristics without considering the edge thickness and width of the sealing gasket, it is verified that the Hertz contact theory is applicable to the metal contact theory of underwater clamp connectors. Then, the sealing simulation with the influence of the detailed dimensions of the sealing gasket is compared with the theoretical result of the direct application of the Hertz contact theory in the underwater clamp connector contact, and the theoretical correction coefficient of metal contact seal for underwater clamp connectors is introduced to solve the errors. The pressure sealing experiment is carried out on six-inch flange and metal sealing gasket, which proves that the coefficient can greatly enhance the theoretical calculation accuracy of the contact sealing of the underwater clamp connector.

Traction resistances of the cotton seeder moulder

The purpose of the study is to determine and analyze the traction resistance of the cotton seeder moulder. The moulder of the cotton seeder consists of a visor, two side dumps and a straight part. The forces acting on the elements of the comb shaper are considered. The basic principles and methods of classical mechanics, mathematical analysis and statistics were used in this study. Analytical dependences for determining the traction resistance of the moulder depending on their design parameters are obtained. It is established that the traction resistance of the moulder movement depends on the physical and mechanical properties of the soil, the depth of its penetration into the soil, the length of the skids, the width of the input edge of the skids and the angles of installation of the side dumps of the moulder. With the optimal parameters of the moulder, the traction resistance of the sowing unit will increase by 0.6-0.8 kN, which practically does not affect the operation of the sowing unit.

Probing on crystallographic structural and surface morphology of hydrothermally synthesized MoS2 nanoflowers consisting of nanosheets

Hydrothermally synthesized MoS2 were obtained and their morphological characteristics were ascertained via electron microscopy. Field emission scanning electron microscope (FESEM) micrographs revealed the formation of nano-flowers by accumulation of nanosheets. The Transmission electron microscopy (TEM) revealed the nanosheets to be of ∼100 nm length and ∼5 nm in edge width. X-ray diffraction pattern analysis showed the formation of 2H polymorph of MoS2, having a long range stacking of about 14 (002) lattice planes in a single crystallite. The Fourier transform infrared (FT-IR) spectroscopic analysis revealed the presence of bridging S22− ligands. Energy dispersive spectroscopy (EDS) analysis associated with the SEM indicates the presence of no other elements except Mo and S in the material. Visualization of atomic structural model and intense lattice plane has been carried out and correlated with crystallographic results. Such findings can be considered as important precursors in both experimental elementary aspects and theoretical approach towards the application-oriented research for crystallographic analysis of nanostructures.

A Study on Focused Ion Beam (FIB) Milling Machining and Fabrication Technology of Nano-Scale Diamond Tool for Machining Fine-Patterns in a Free-Form Surfaces.

Recently, the technology of the industry has been increasing for diffractive optical elements, holograms, optical components, and next-generation display components. The advanced high value-added industry is designing fine patterns on ultra-precision optical components and applying them to various industries. In the case of the ultra-fine pattern, a contact-type machining technique is required because it requires a precise pattern in nano-scale units. In this paper, the fabrication technology of ultra-precision diamond which is essential in the ultra-precision processing technology was suggested. The material used in the experiment was a single-crystal diamond tool (SCD), and the equipment for machining the SCD used a focused ion beam (FEI COMPANY, system Nova 600) equipment. The back fire method was applied without metal coating in order to carry out the process study and the focused beam of 30 keV Ga+ ions were carried out processing for various fabrication of diamond cutting tools. As a result of applying the backfire method through the process experiment, the cutting edge width of the ultra-precision diamond tool was verified 275 nm.

Femtosecond Laser Trimming with Simultaneous Nanostructuring to Fine Piercing Punch to Electrical Amorphous Steel Sheets.

A CVD (Chemical Vapor Deposition) diamond coated tungsten carbide (WC) and cobalt (Co) sintered alloy punch was trimmed by the femtosecond laser machining to sharpen its edge with about 2 μm and to simultaneously make nanostructuring to its side surface. In addition to the sharpened edge, its edge profile was formed to be homogeneous enough to reduce the damage layer width by piercing the electrical amorphous steel sheet stack. Each brittle sheet in the stacked work was damaged to have three kinds of defects by piercing; e.g., the droop-like cracking in the thickness and at the vicinity of hole, the wrinkling in peak-to-valley with partial cracking on the peaks, and the circumferential cracking. When using the WC (Co) punch with the inhomogeneous edge profile in the sharpened edge width, these three damages were induced into each sheet and the maximum damage width exceeded 80 μm. When using the punch with the sharpened edge and homogeneous edge profile, the wrinkling mode was saved and the total affected layer width was significantly reduced to less than 20 μm. Through the precise embossing experiments, this effect of punch edge profile condition to the induced damages was discussed with a statement on the nanostructuring effect on the reduction of damaged width in electrical amorphous steel sheets. The developed tool with the sharpened edge and homogenous edge condition contributes to the realization of a low iron loss motor with a reduced affected layer width.

High-dynamic-resolution optical edge detection based on liquid crystal diffractive moiré lenses with a tunable focal length.

In this Letter, we experimentally demonstrate liquid crystal-based moiré lenses with a wide and tunable focal length by direct-writing photoalignment. Our moiré lenses, which consist of two cascaded diffractive optical elements, have a large range of refractive power between $\pm 0.85\;{{\rm m}^{- 1}}$ at 532 nm and a mutual rotation between $\pm 90^\circ$ with high diffraction efficiency ($\gt\!{75}\%$). Based on the as-designed moiré lenses, we propose high-dynamic-resolution optical edge detection without any axial shift or substitution of components. The minimum edge width is 13.2 µm and can be adjusted within 100 µm by mutual rotation of this device, which has great potential to be used in adaptive and compact optical systems.

Numerical study on the biomimetic trailing edge in the environment of a high-pressure turbine stage

In this study, the whisker structure of a harbor seal is applied to the trailing edge of a high-pressure turbine stage to reduce energy loss. The method to produce biomimetic geometry is provided. Two cases are studied in this paper including a prototype of a high-pressure turbine stage and this stage with the biomimetic trailing edge. The delayed detached-eddy simulation (DDES) method is used to simulate the flow of the stages. The energy loss coefficient of the turbine stage with the biomimetic trailing edge is significantly reduced. The analysis of the local entropy generation rate shows that the wake loss of the biomimetic stage and the loss in the blade passage are greatly reduced. Two reasons for the widening of the wake of the prototype vane during the downstream movement are analyzed. For the biomimetic stage, the Karman vortices are completely suppressed and transformed into small vortices with strong three-dimensional motion. The wake width of the biomimetic trailing edge is narrowed and the speed recovery becomes faster. This leads to the reduction of the wake loss and the interaction between the wake of the vane and the downstream blade.

Wear performance and mechanisms of PCBN tools in boring of powder metallurgy steels

Wear performance and mechanisms of PCBN tools with different CBN content (80% vol. and 95% vol.) and cutting edge geometry (honed edge radius, 0.05 mm chamfered edge width, and 0.10 mm chamfered edge width) in boring powder metallurgy (PM) steels had been evaluated. Post-cutting examination of the worn cutting inserts was performed using focus variation microscopy (FVM), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). The advanced three-dimensional wear characterization parameters WRM, WMD, WAM, WMH, and WAA are used to measure the wear of PCBN tools. A novel characterization method of removed material (η1 = WMD/WRM) and adhered material (η2 = WMH/WAM) was used to measure the trend of tool wear in this paper. With the increasing of CBN content, the PCBN tool wear parameters WRM, WMD, and WAA were decreased; adhesion was increased by WAM and WMH parameter characterization. For the variation of cutting edge geometry, chamfered edge showed a higher tool life and better wear performance than honed edge radius. With the increasing of chamfered edge width from 0.05 to 0.10 mm, the three-dimensional wear WRM, WMD, WAM, and WMH were increased. WAA showed an opposite trend and parameters η1 and η2 showed a not convergence trend. Besides typical wear mechanisms such as diffusion, adhesion, abrasive, microchipping was observed on PCBN tool; the tool protection layer (TPL) formation and peeling and impact load could be the reasons to explain the microchipping that occurred on cutting edge. Tool life is measured by surface roughness and calculated according to the number of workpieces processed. The results showed that PCBN tool with 95% vol. CBN content and 0.10 mm chamfered edge width achieves higher tool life.

Optimization of printing parameters of 3D-printed continuous glass fiber reinforced polylactic acid composites

A novel 3D printing strategy for continuous glass fiber reinforced polylactic acid (CGF/PLA) composites was proposed. CGF/PLA filament was prepared by a melting impregnation device, and then CGF/PLA filament was directly supplied to the self-modified 3D printing device. The impregnation process was optimized systematically, and the fiber content reached up to 45 wt%. A specific compatibilizer was used and the amount of compatibilizer was optimized to enhance the interfacial bonding between fiber and polymer. The effects of printing parameters such as nozzle diameter, edge width, layer thickness, printing speed and temperature on the mechanical properties and microstructure of the final printed products were studied. The flexural strength and flexural modulus of the printed products reached 312 MPa and 21.5 GPa, respectively. The fabrication strategies proposed in this study can provide a low-cost and high-strength method for the industrial application of 3D printed continuous fiber reinforced thermoplastic composites.

An Experiment-Based Simplified Method for the Model of Building Groups in CFD Simulation

Computational Fluid Dynamics (CFD) has been widely used in the simulation and analysis of community or urban wind environments. However, the CFD-based wind simulation of large-scale building groups usually consumes a lot of computing resources with high computing costs. To improve the efficiency of CFD-based wind simulation, this paper presents an experiment-based simplified method for the model of building groups. Two rectangular buildings are adopted as the basic unit and four control parameters (B/L, W/L, H/L, and D/L) are selected as the experiment factors to analyze the geometrical relationship of the two buildings. Note that L, W, and H, respectively, represent the windward edge length, width, and height of a building, B is building interval distance, and D is the distance between two building center axes. Then, a single factor experiment and an orthogonal experiment are designed and performed to determine the reasonable value range of each factor. Based on the experiment results and actual situation, the value ranges of four factors for the simplification of building group models are determined as follows: B/L∈{0, 1.5}, W/L∈{0, 2}, D/L∈{0, 0.25}, and H/L∈{0, 1}. Furthermore, a real case is presented to evaluate the performance of the proposed simplified method. The results indicate that the simplified method is able to improve the efficiency of CFD-based wind simulation of building groups, with the number of buildings decreasing from 620 to 395 (by 36.3%), and the number of tetrahedral grids decreasing from 8,832,199 to 7,766,778 (by 12.1%). Thus, this research contributes to the CFD-based wind simulation method of large-scale building groups and the analysis of the urban wind environment.

Drop-on-demand printing of edge-enhanced and conductive graphene twin-lines by coalescence regulation and multi-layers overwriting

Fabrication of straight and highly conductive graphene lines, the cornerstones of high-performance graphene-based printed electronics, still faces considerable challenges. We have developed a convenient and effective way to print edge-enhanced highly conductive graphene twin-lines by coalescence regulation and multi-layers overwriting (CRMO), which enhances both outline accuracy and electrical conductivity. The overlapping traces and wavy edges were eliminated by droplets coalescence at the expense of introducing discrete footprints, which were transformed into continuous lines by multi-layers overwriting. We successfully fabricated the edge-enhanced graphene twin-line with an edge width of 72.33 ± 7.96 μm and a linear resistivity of 0.188 ± 0.160 kΩ μm−1, yielding the coinstantaneous enhancement of outline accuracy, printing efficiency, and electrical conductivity. Printed graphene twin-lines achieve one of the lowest relative linear resistivity reported so far and a conductivity of 359.88 S m−1. We attributed the highly concentrated and tightly interconnected graphene flakes at the edge to the synergetic effect of CRMO. Finally, we have demonstrated the feasibility of CRMO by printing graphene line resistors with excellent linearity and broad resistance ranges. Such findings establish relationships among the printing method, line morphologies, flakes distribution, and electrical conductivity. This work will be of great significance for the self-assembly of graphene-based functional materials and graphene-based printed electronics development.

Pair production in asymmetric Sauter potential well

Electron-positron pair production in asymmetric Sauter potential well is studied, where the potential well has been built as the width of the right edge fixed but the left side of the well is changeable at different values. We study the momentum spectrum, the location distribution and the total pair numbers in this case of asymmetric potential well and compare them with the symmetric case. The relationship between created electron energy, the level energy in the bound states and the photon energy in the symmetric potential well is used to the studied problem for the created electrons in the asymmetric potential well and its validity is confirmed by this approximation. By the location distribution of the electrons we have also shown the reason why the momentum spectrum has an optimization in the asymmetric well compared with the symmetric one.

Structure Analysis and Optimization Design of FDM Wire Extruder Screw

In order to improve the melt extrusion efficiency and extrusion stability of FDM wire extruder, ANSYS finite element software was used to analyze the flow field of the extruder screw. The effect of screw pitch, depth of screw groove, width of screw edge and length of metering section on velocity field, pressure field, temperature field and shear rate were studied by orthogonal test method, and the optimal combination of factors was obtained, then the optimized screw was tested and verified. The results show that when the screw pitch is 15mm, the depth of screw groove is 1.3mm, the width of screw edge is 1.5mm and the length of measuring section is 85mm, the wire extruder of FDM is smooth, efficient and safe.

Numerical solution of the schrödinger equation with periodic coulomb potential

This paper investigates the energy spectrum of a periodic one-dimensional Coulomb potential. The Schrödinger equation is solved numerically by our newly developed filter method (Phys. Rev E 96(3), 033302 (2017)). We observe that the energy spectrum can be obtained with a limited number of lattice. The results show the presence of an energy band structure as a function of lattice width and edge width. The comparison with the other potential model is also discussed.

Human Activity and Forest Degradation Threaten Populations of the Nigeria\u2013Cameroon Chimpanzee (Pan troglodytes ellioti) in Western Cameroon

Increased human activities such as commodity-led deforestation, extension of agriculture, urbanization, and wildfires are major drivers of forest loss worldwide. In Cameroon, these activities cause a loss of suitable primate habitat and could ultimately threaten the survival of chimpanzees (Pan troglodytes). We derived independent estimates of the population size of the Endangered Nigeria–Cameroon chimpanzee (Pan troglodytes ellioti) in Kom-Wum Forest Reserve, Cameroon, and surrounding unprotected forest areas through 1) direct observations, 2) camera trapping, 3) distance sampling, 4) marked nest counts, and 5) standing crop nest counts. In addition, we georeferenced signs of chimpanzee and human activity along line transects. We used a generalized linear mixed model to predict the occurrence of chimpanzees in response to edge length (measured as the perimeter of core forest patches), core area of forest patches (measured as area of forest patches beyond an edge width of 100 m), habitat perforation (measured as the perimeter of nonforested landscape within core forest patches), patch size(measured as area of forest patches), and forest cover. Chimpanzee density estimates ranged from 0.1 (direct observation) to 0.9 (distance sampling) individuals km−2 depending on estimation method with a mean nest group size of 7 ± 5.4 (SD). The mean encounter rate for signs of chimpanzee activity was significantly higher in mature forests (2.3 signs km−1) than in secondary forests (0.3 signs km−1) and above 1000 m elevation (4.0 signs km−1) than below 1000 m (1.0 signs km−1). The mean encounter rate for signs of human activity was significantly higher in secondary (8.0 signs km−1) than in mature forests (0.9 signs km−1). Secondary forests, habitat perforation, and edge length had a significant negative effect on the occurrence of chimpanzee signs. Overall, human activity and forest degradation affected the number of observed chimpanzee signs negatively. Regular antipoaching patrols and reforestation programs in degraded areas could potentially reduce threats to populations of endangered species and may increase suitable habitat area.

Radioanatomic study on the role of Hadad-Bassagasteguy flap in skull base reconstruction in endoscopic endonasal approach

Objective: To evaluate the value of Hadad-Bassagasteguy flap (HBF) in endoscopic endonasal approaches (EEA) skull base reconstruction by radioanatomic measurements on CT of the skull base of Chinese adults. The following data in terms of anterior skull base defect and reconstruction, sphenoid platform area and middle skull base defect and reconstruction including sphenoid platform and sella area, clivus area defect and reconstruction, and HBF were collected and assessed. Methods: CT image data of 42 Chinese adults were selected to obtain radioanatomic measurement data related to HBF, anterior skull base defect and reconstruction, middle skull base defect and reconstruction, and defect and reconstruction of clivus area. SPSS 26.0 software was used to analyze the data. Results: The radioanatomic measurement data about HBF and skull base of 42 Chinese adults were obtained. The width of the leading edge of HBF [(37.49±2.86) mm] was 6 mm more than the anterior skull base width at the level of the anterior ethmoidal artery [(30.87±8.61) mm], and the width of the trailing edge of HBF [(42.61±3.95) mm] was also 6 mm more than the anterior skull base width at the level of the sphenoethmoidal junction [(26.79±2.79) mm]. The total length of HBF including the pedicle [(79.68±4.96) mm] was 6 mm more than the length of the anterior skull base reconstruction [(54.06±8.67) mm], and the length of HBF without pedicle [(46.27±3.14)] mm was 6 mm more than the length of anterior skull base defect [(30.87±8.61) mm]. The trailing edge width was 6 mm more than the planum sphenoidal width at the level of the optic strut [(30.87±8.61) mm]. The total length of HBF including the pedicle was 6 mm more than the length of the planum sphenoidal, and the sella reconstruction [(64.44±10.25) mm], also was 6 mm more than the length of the planum sphenoidal reconstruction [(73.61±8.28) mm]. The length of HBF without pedicle was 6 mm more than the length of the planum sphenoidal, and the sella defect [(27.88±3.74) mm], also was 6 mm more than the length of the planum sphenoidal defect [(15.50±3.38) mm]. The width of the leading edge of HBF and the width of the trailing edge were both 6 mm more than the width of clivus reconstruction at the level of the foramen lacerum [(21.68±2.30) mm]. The total length of HBF including pedicles was 6 mm more than the clivus reconstruction length [(67.09±5.44) mm], while the length of HBF without pedicles was also 6 mm more than the clivus defect length [(37.19±3.80) mm]. Conclusions: In this study, the radiosanatomic measurements ensured that HBF could provide sufficient tissue flap for the reconstruction of the anterior skull base and sphenoid plateau and extend the reconstruction area to sella and clivus. Preoperative radiosanatomic measurement can be used to predict the size of HBF required for skull base reconstruction, which provides important guidance for flap harvest.

Enhancement of Contour Smoothness by Substitution of Interpolated Sub-Pixel Points for Edge Pixels

This study designed a sub-pixel precision edge detecting algorithm to enhance contour smoothness. First, the coordinate value of RGB pixel is projected on the space line of R=G=B to obtain gray image. Then, pixel edges are located using a Canny detector. Next, the edge width is thinned to a single pixel using a morphological thinning operation. Finally, sub-pixel-level smooth contours are extracted by interpolation. In this sub-pixel level contour extraction process, a Single-Pixel-Multi-Point interpolation method was developed to enhance edge smoothness and obtain high precision in edge estimation. This method divides edges in a $3\times 3$ pixels block into nine arrangement modes. According to the arrangement of the eight neighborhoods of a centered edge pixel, different locations of interpolated sub-pixel points are calculated by interpolation with Bezier curves. For symmetrically arranged linear edge pixels, this method can be used to determine the exact contour. Experimental results showed that the proposed algorithm can improve the smoothness of image edge contour. As the curvature of the edge increases, the maximum systematic error will increase. For the edge pixel centered in the $3\times 3$ pixels block and two pixels located at the corner of one side, the max systematic error is 0.5 pixel. For two edge pixels aligned in a single row or column with one located at a corner, the max systematic error is 0.25 pixel.

EXAFS and XANES study of cobalt complexes synthesized with ligands of chloroaniline and fluoroaniline dithiocarbamate

The cobalt [Co(II)] complexes (03 nos) were synthesized using various ligands of chloroaniline and fluoroaniline dithiocarbamate. The synthesized Co(II) complexes were studied for different physical, structural and chemical parameters using XANES and EXAFS conducted on DXAFS beamline BL-8, Indus 2, Synchrotron source. The EXAFS spectra recorded for Co(II) complexes were used for computation of the bond length, chemical shift, effective nuclear charge, principal absorption maxima and edge width using Athena and Origin 6.0 software. The results of the study revealed that, the synthesized cobalt complexes showed higher value for K-absorption edge (Ek) and Absorption maxima (EA) than Co metal. The Chemical shift (ΔEK) value for Co(II) complexes were ranged 1.17-4.52 eV. The Shift of principal absorption maxima (ΔEA) value for Co(II) complexes were ranged 0.65-4.18 eV. The Edge width of three different complexes of cobalt [Co(II)] synthesized with ligands of chloroaniline/fluoroaniline dithocarbamate ranged 6.60-11.14 eV. The bond length calculated by LSS method ranged 1.41-2.20 Å for different complexes whereas the bond length calculated by FT method ranged 1.26-3.06 Å. The Lytle’s method and Levy’s method gives the bond length ranged 2.44-3.08 Å and 1.97-2.58 Å, respectively for studied complexes.

Fault Detection Algorithms for Achieving Service Continuity in Photovoltaic Farms

This study uses several artificial intelligence approaches to detect and estimate electrical faults in photovoltaic (PV) farms. The fault detection approaches of random forest, logistic regression, naive Bayes, AdaBoost, and CN2 rule induction were selected from a total of 12 techniques because they produced better decisions for fault detection. The proposed techniques were designed using distributed PV current measurements, plant current, plant voltage, and power. Temperature, radiation, and fault resistance were treated randomly. The proposed classification model was created using the Orange platform. A classification tree was visualized, consisting of seven nodes and four leaves, with a depth of four levels and edge width relative to parents. Thirty fault features attributes, four of them major, supported fault detection through the selected algorithms. The different fault types occurring in a PV farm were considered, including string fault, string-to-ground fault, and string-to-string fault. The selected classifiers were evaluated, and their performance was compared with respect to the important decision factors of precision, recall, classification accuracy, F-measure, specificity, and area under the receiver-operating curve. Using Simulink/MATLAB, a grid-connected 250-kW PV farm was implemented, including the converters control. Results confirmed that AdaBoost achieved the best performance.

Lattice distortion-enhanced superlubricity of (Mo, X)S2 (X = Al, Ti, Cr and V) with moiré superlattice.

Two-dimensional (2D) materials with the advantage of low interlayer shear strain are ultilized as lubricants in aerospace and precision manufacturing. Moiré superlattices (MSL), with attractive physical properties of electronic structures, interlayer hybridization and atomic forces, have been widely investigated in superlubricity, which is caused by elimination of interlayer lock-in by incommensurate atomic reconstruction. Although the foundations of superlubricity and the development of 2D lubricants via vanishing friction have been investigated, it is still important to comprehensively reveal the influence of MSL on the interlayer van der Waals (vdW) interactions of 2D lubricants. Here, the contributions of lattice distortions of solute-doped twisted bilayers (Mo, X)S2 (X = Al, Ti, V and Cr) to superlubricity are comprehensively investigated by high-throughput modelling and DFT-D2 calculations. It is revealed that the lattice distortion not only breaks the interlayer balance of repulsion and van der Waals interactions but also yields layer corrugation. These layer-corrugation-induced changes of the interlayer interactions and spacing distances are utilized to optimize lubricity, which matches with the experimental friction coefficients in the order of (Mo, Al)S2 > (Mo, Cr)S2 > MoS2 >(Mo, V)S2 >(Mo, Ti)S2. The evolutions of the band structures show an exponential relationship of the band edge width and layer deformations, paving a path to accelerate the development of advanced superlubricity materials via lattice distortions.