Статті в журналах: "Conical gap"

1

KRESTIN, Evgeny A., and Grigoriy V. SEREBRYAKOV. "HYDRODYNAMIC CALCULATION OF CONTACTLESS SEALS WITH PLANE SLOTS IN DRIVES OF ELECTRIC POWER SYSTEMS." Urban construction and architecture 11, no. 2 (December 15, 2021): 171–77. http://dx.doi.org/10.17673/vestnik.2021.02.22.

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Non-contact seals with fl at slott ed gaps of drives of electric power systems used in switchgears of hydraulic units, as well as in pumps and hydraulic motors have been investigated. Calculation of seals based on average clearance results in an underestimation or overestimation of the leakage rate compared to the operational values. The regularity of the distribution of pressure and fl ow rate in the gap of a fl at conical slot is determined, and formulas for the fl ow rate (leakage) and friction forces acting on the walls of the conical slot are found. To solve the problem, the approximate Navier-Stokes and fl ow continuity equations are used. Several special cases of the fl ow of the working fl uid in diff erent gaps are considered: a plane-parallel gap with an oscillating wall and at a constant pressure gradient and a conical gap at diff erent ratios of the pressure drop and the frictional action of the moving channel wall. When the wall oscillates in a conical gap and constant pressure, the presence of an extremum is characteristic. In this case, an excess pressure appeared in the slott ed gap, creating a supporting force, and the pressure value became high enough. When the lower wall of the conical slot moves in the direction of the increasing gap, the pressure inside the slott ed channel, under certain conditions, can reach a complete vacuum, the value of which is limited by the bulk strength of the liquid and the pressure of saturated vapor at a given temperature. When the pressure drop and oscillations of the wall of the conical gap are additive, then at a suffi ciently high velocity of the wall movement, the pressure inside the slot can even increase and exceed the value of the supplied pressure.

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2

Koprowski, Mariusz. "An analysis of lubricating medium flow through unsymmetrical lubricating gap of conical slide bearing." Polish Maritime Research 14, no. 4 (October 1, 2007): 59–63. http://dx.doi.org/10.2478/v10012-007-0041-x.

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An analysis of lubricating medium flow through unsymmetrical lubricating gap of conical slide bearing This paper presents a computer analysis of lubricating medium flow through unsymmetrical lubricating gap of conical slide bearing. Numerical calculations were carried out with the use of the software Matlab 7.1 and Mathematica 5.2 for example conical slide bearings of different values of cone apex angles of pin and sleeve and set values of relative eccentricity and skewing angle as well as dimensionless bearing length equal to 1.

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3

Sinha, P., P. Chandra, and S. Bhartiya. "Analysis of a non-constant gap externally pressurized conical bearing with temperature and pressure dependent viscosity." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 214, no. 5 (May 1, 2000): 699–710. http://dx.doi.org/10.1243/0954406001523704.

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The present paper analyses an externally pressurized non-constant gap conical bearing rotating with a uniform angular velocity. The lubricant is assumed to be incompressible and its viscosity varies with both pressure and temperature. Although the inertia effect due to lubricant flow has been neglected, rotational inertia is taken into account. The governing system of coupled momentum and energy equations, in conical coordinates, is solved numerically using the finite difference method, to determine various bearing characteristics. The effect of the viscosity-pressure exponent, , on various characteristics of the bearing has been studied. It is seen that variation of does not produce any significant change in the load capacity for convergent and constant gap conical bearings. For the divergent gap also, no significant difference is seen when the gap is slightly divergent. However, for highly divergent gaps, the load capacity increases with an increase in . It is also seen that variation in does not produce any significant change in torque of the bearing.

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4

Wang, J. M., and P. H. J. Schellekens. "Tri-Conical Gap-Shaped Externally Pressurized Gas Bearing Pads." Tribology Transactions 37, no. 4 (January 1994): 850–56. http://dx.doi.org/10.1080/10402009408983368.

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5

KORNEYEV, А. Yu, A. V. SYTIN, А. V. KUZAVKA, and E. V. MISHCHENKO. "THE MATHEMATICAL MODEL OF CALCULATION OF THE THRUST CONICAL FOIL BEARINGS." Fundamental and Applied Problems of Engineering and Technology 3 (2020): 3–10. http://dx.doi.org/10.33979/2073-7408-2020-341-3-3-10.

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The question of creating a unified method of calculation for the thrust and conical part of the combined thrust conical foil bearings. Mathematical model for calculating the turbulent flow of a lubricant in the conical and thrust parts of foil bearings. The design of the bearing and foil, the function of the gap in the lubricant layer of the bearing, the Reynolds equation and the equation of deformations of elastic elements are presented.

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6

Kalita, W., N. Yegani, Cz M. Rodkiewicz, and J. S. Kennedy. "On the Laminar Flow Characteristics of Conical Bearings. Part II—Experimental Verification." Journal of Tribology 108, no. 1 (January 1, 1986): 59–64. http://dx.doi.org/10.1115/1.3261144.

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The laminar flow characteristics of the externally pressurized central recess conical bearings with narrow gaps, predicted theoretically in Part I of this paper, have been verified experimentally. Two main effects on the performance of conical bearings have been investigated, namely: the effect of nonconstant film thickness along the gap of the bearing and the effect of rotation. It was found that experimental pressure distributions and load capacity of the constant and divergent gap bearings were in close agreement with the theoretical data for the low rotational velocities however, with the increased rotation, the experimental values were higher than theoretically predicted. The experimental values of pressure, load capacity, and the torque of convergent gap bearings were found higher than theoretical.

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7

Chen, Chi Feng, Yu Cheng Cheng, and Chia Jen Ting. "Improved Antireflection Property of Subwavelength Structures Based on Finite Difference Time Domain Method." Applied Mechanics and Materials 364 (August 2013): 780–84. http://dx.doi.org/10.4028/www.scientific.net/amm.364.780.

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A kind of subwavelength structure array is numerically investigated to improved antireflection property. Based on finite difference time domain method, we consider adding a small conical structure in the gap between the pure periodic conical subwavelength structure to analylz the antireflection property in spectral range of 400-1100 nm. The improved antireflection property of subwavelength structures have distinguishing characteristic in particular places. The result shows the morphological effect on reflectance of new conical shape subwavelength structures.

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8

Chen, Chi-Feng, Yu-Cheng Cheng, and Chia-Jen Ting. "Improved Antireflection Properties of an Optical Film Surface with Mixing Conical Subwavelength Structures." Journal of Nanomaterials 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/459325.

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Based on finite difference time domain method, an optical film surface with mixing conical subwavelength structures is numerically investigated to improve antireflection property. The mixing conical subwavelength structure is combined with the pure periodic conical subwavelength structures and the added small conical structures in the gap between the pure periodic conical subwavelength structures. The antireflection properties of two types of subwavelength structures with different aspect ratios in spectral range of 400–800 nm are analyzed and compared. It is shown that, for the mixing type, the average reflectance is decreased and the variances of the reflectance are evidently smaller. When the added structure with a better aspect ratio exists, the average reflectance of the surface can be below 0.30%. Obviously, the antireflection properties of the optical film surface with mixing conical subwavelength structures can be improved.

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9

Saxena, Snigdha, Peeyush Chandra, and Prawal Sinha. "THD Analysis of Non-Constant Gap, Externally Pressurized Conical Bearings." Tribology Transactions 38, no. 2 (January 1995): 438–44. http://dx.doi.org/10.1080/10402009508983426.

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10

Oh, Dong Hyeon, and Gil Ho Yoon. "A Study of Longitudinal Waveguide with Band Gap Using Cylindrical and Conical Shape Periodic Structure." Applied Sciences 11, no. 16 (August 6, 2021): 7257. http://dx.doi.org/10.3390/app11167257.

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This research presents the theoretical and experimental studies for cylindrical and conical periodic structures to control longitudinal wave motion. Many relevant researches exist to stop and pass a certain frequency wave without active devices with periodic structures called metamaterials. To modify or control longitudinal wave propagation, i.e., passing or blocking mechanical wave within specific frequency ranges, repeated mass-spring systems or metamaterials can be applied. By integrating a few identical structural components to form a whole structure, it is possible to make a mechanical filter for wave propagation. Most studies rely on straight bar with cylindrical structure. Thus, with a unit cell that have a cylindrical and conical structure, this research presents the extensions toward the studies of the wave motions for straight and curved bars with finite element simulations and experiment studies. The results show that the hybrid cylindrical and conical periodic structures can be effective in terms of wave motion control and stiffness.

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11

Radwan, Samah I., H. El-Khabeary, and A. G. Helal. "Study of the secondary electron emission coefficient using disc and conical electrodes." Canadian Journal of Physics 94, no. 12 (December 2016): 1275–81. http://dx.doi.org/10.1139/cjp-2016-0334.

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In this work, glow discharge is formed by similar disc and conical electrode shapes from aluminum material at constant anode–cathode gap distance equal to 10 cm. The breakdown voltage and discharge current against the pressure × distance are measured at different pressures. The secondary electron emission coefficient is calculated using Townsend’s secondary ionization coefficient equation. A comparison is made between the breakdown voltage, discharge current, and secondary electron emission coefficient using disc and conical anode–cathode electrodes. Hence with a product of pressure and distance equal to 6 Torr cm, the secondary electron emission coefficient value of conical shape is higher than for the disc shape.

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12

Kalita, W., Cz M. Rodkiewicz, and J. S. Kennedy. "On the Laminar Flow Characteristics of Conical Bearings. Part I—Analytical Approach." Journal of Tribology 108, no. 1 (January 1, 1986): 53–58. http://dx.doi.org/10.1115/1.3261143.

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An analysis has been made of the characteristics of externally pressurized central recess conical bearings with nonconstant film thickness under the assumption of isothermal laminar flow of a viscous incompressible fluid. The flow in the narrow gaps that may be convergent, constant, or divergent has been approximately determined on the basis of the lubrication theory with convective inertia neglected except for that part which is due to rotation. The pressure distribution along the gap, the load capacity, and the torque of the bearings, were theoretically predicted. It was found that, while the gap is very narrow, both the load capacity and the torque for the convergent case decrease moderately, and for the divergent case increase significantly with respect to the constant gap bearing, provided with flow rate, rotational velocity and the film thickness at the outlet of the gap are the same.

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13

Liang, Jian Ping, Zi Lu Zhao, Xiong Feng Zhou, Hao Yuan, Hong Li Wang, Wen Chun Wang, and De Zheng Yang. "The influences of shielding gas and quartz tube on discharge properties and reactive species productions of nanosecond pulsed gas–liquid discharge." Journal of Physics D: Applied Physics 55, no. 19 (February 16, 2022): 195204. http://dx.doi.org/10.1088/1361-6463/ac4fd5.

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Abstract In this paper, shielding gas (He) and shielding quartz tube (straight tube and conical tube) is added to nanosecond pulsed He gas–liquid discharge (G-LD) to limit the air diffusion into plasma, and for the purposes of enhancing the plasma volume and productions of ċOH and H2O2. The plasma properties, including current–voltage waveforms, the temporal-resolved discharge images, optical emission spectra, gas temperature, electron density, and the ċOH and H2O2 productions are analyzed and compared among different discharges generated under the cases of no shielding, shielding He gas, shielding straight tube, and shielding conical tube. The results show that adding extra shielding gas and tubes in the discharge reactor can decrease the gas temperature and electron density, but enhance the plasma volume and area of plasma-liquid interface in comparison with no shielding case. Besides, the addition of shielding gas has the most benefit for enhancing the productions of ċOH and H2O2 produced by G-LD. Adding a shielding conical tube slows down the decrease extent of ċOH and H2O2 productions caused by increasing discharge gap. When the discharge gap excesses 6 mm, adding a shielding conical quartz also has an obvious increase effect on the production of ċOH and H2O2 in compared with no shielding case. While adding a shielding straight tube with small diameter has a little effect on H2O2 production, even a negative effect on ċOH production.

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14

Pereira, Francisco Estêvão Simão, and Maurício Henrique Costa Dias. "On the Design of Conical Antennas for Broadband Impedance Matching Performance." International Journal of Antennas and Propagation 2017 (2017): 1–13. http://dx.doi.org/10.1155/2017/1691580.

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In the scope of broadband radiators, the biconical antenna, or its monopole conical counterpart, is long known to be a proper choice. One common form of such radiator, the spherically capped conical antenna (SCCA), has closed-form solution to its input impedance, from which the broadband performance potential is easily verified. Nonetheless, from the design perspective, apart from a few clues inferred from existing solutions, little is found to accurately guide the choice of the main geometrical parameters of the antenna that will enable it to comply with a set of imposed bandwidth requirements. This paper proposes a simple 10-step sequence to derive conical or biconical antenna design charts. These charts provide straightforward information on the geometrical limits within which the required antenna impedance matching broadband performance is achieved. The method is assessed for the SCCA and the open conical antenna (OCA) using theoretical and simulated estimates of the input impedance. A discussion on the impact of the cap and the feed gap is included.

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15

Wimmer, Manfred. "An experimental investigation of Taylor vortex flow between conical cylinders." Journal of Fluid Mechanics 292 (June 10, 1995): 205–27. http://dx.doi.org/10.1017/s0022112095001492.

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Viscous flows and instabilities between conical cylinders are described which result from rotating an inner cone while the outer one is at rest. Both cones have the same apex angle resulting in a constant width of the gap between the bodies. The laminar basic flow is tree-dimensional. Owing to different centrifugal forces on the cone's surface one obtains regions of sub- and supercritical flows in the annulus. The Taylor vortices generated can be steady or unsteady, so that toroidal or helical vortices travel through the closed system, depending on different initial and boundary conditions. Furthermore, combinations of steady toroidal and unsteady helical vortices are possible. The influence of the governing parameters, like acceleration rate, gap width, end plates and so on is discussed. A comparison with available calculations is made.

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16

Liang, Gaojie, Lijun Liu, Haiqian Zhao, Cong Li, and Nandi Zhang. "Study on droplet nucleation position and jumping on structured hydrophobic surface using the lattice Boltzmann method." Thermal Science, no. 00 (2021): 149. http://dx.doi.org/10.2298/tsci201206149l.

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In this study, droplet nucleation and jumping on the conical microstructure surface is simulated using the Lattice Boltzmann Method (LBM). The nucleation and jumping laws of the droplet on the surface are summarized. The numerical results suggest that the height and the gap of the conical microstructure exhibit a significant influence on the nucleation position of the droplet. When the ratio of height to the gap of the microstructure(H/D) is small, the droplet tends to nucleate at the bottom of the structure. Otherwise, the droplet tends to nucleate towards the side of the structure. The droplet grown in the side nucleation mode possesses better hydrophobicity than that of the droplet grown in the bottom nucleation mode and the droplet jumping becomes easier. Apart from the coalescence of the droplets jumping out of the surface, jumping of individual droplets may also occur under certain conditions. The ratio of the clearance to the width of the conical microstructure(D/F) depends on the jumping mode of the droplet. The simulation results indicate that when the D/F ratio is greater than 1.2, the coalescence jump of droplets is likely to occur. On the contrary, the individual jump of droplets is easy to occur.

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17

Chervyakov, V. M., and A. A. Koptev. "Flow of a Newtonian fluid in the gap between conical permeable surfaces." Journal of Engineering Physics and Thermophysics 79, no. 2 (March 2006): 301–8. http://dx.doi.org/10.1007/s10891-006-0101-6.

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18

Liu, Xiaohui, and Qi Geng. "Effect of contact characteristics on the self-rotation performance of conical picks based on impact dynamics modelling." Royal Society Open Science 7, no. 5 (May 2020): 200362. http://dx.doi.org/10.1098/rsos.200362.

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Conical picks have a harsh working environment and 70% of their failures are caused by wear. It has been found that conical picks can rotate while interacting with the working material. This self-rotation ability is an important factor affecting pick wear, but the self-rotation mechanism remains unclear. Researching the mechanism involves the impact and friction dynamics of the interaction between a pick and its holder. Thus, a dynamic finite-element numerical model for the pick–holder interaction is established. How the handle–holder gap width, pick body and handle lengths and pick handle diameter affect the settling time and the percentage of time with no contact is studied to compare the numerical results with the equivalent effects on the rotation angle in experiments. Doing so indicates that the main factor in the self-rotation ability of a conical pick is not the magnitude of the contact load but its duration. The present research provides a new method for revealing the mechanism for the self-rotation of conical picks.

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19

KRESTIN, Evgeny A. "ON THE PROBLEM OF VISCOUS INCOMPRESSIBLE FLUID FLOW IN A FLAT CONICAL SLOTTED CHANNEL." Urban construction and architecture 8, no. 3 (September 15, 2018): 51–54. http://dx.doi.org/10.17673/vestnik.2018.03.11.

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A precision pair operating under misalignment conditions, i.e. at a distortion of mobile elements of contactless consolidations is analyzed. The fl ow of a viscous incompressible fl uid in a fl at conical slit gap is investigated. Since the boundary-value problem does not have an exact solution, an approximate analytical solution was found in the work that does not depend on boundary conditions. The equations of motion of a fl uid are solved in the Navier-Stokes form by the method of small perturbations. The hydrodynamic parameters of a viscous fl uid as it moves through a conical slit gap are determined. The profi le of the velocity of the fl uid in the form of the sum of a pressure fl ow with a constant pressure drop and fl ow due to the oscillation of the channel wall is constructed. Graphic illustrations are given with high and low frequency limits of oscillations.

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20

Jayakumari, Chithra, Probal Nag, Sai Isukapalli, and Sivaranjana Vennapusa. "Exploring the Excited-State Nonadiabatic Effects in the Semisaturated Planar Tetracoordinated Carbon Molecule C7H4." Atoms 10, no. 1 (January 19, 2022): 10. http://dx.doi.org/10.3390/atoms10010010.

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We theoretically study the nonadiabatic relaxation dynamics of low-lying singlet excited-states of semisaturated planar tetracoordinated carbon molecule, C7H4. This molecule possesses a stable C2v ground-state equilibrium geometry. The three low-lying singlet states, S1, S2 and S3, lie in the energy gap of about 1.2 eV. The potential energy surfaces constructed within the quadratic vibronic coupling formalism reveal multiple conical intersections in the Franck-Condon region. Upon photoexcitation to S3, the wavepacket decays rapidly to lower states via these conical intersections. We also observe the wavepacket transfer to S3 during the initial wavepacket evolution on lower states, suggesting the nonadiabatic behavior of photoexcited planar C7H4.

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21

Khoo, B. K., Ovinis Mark, and Nagarajan Thirumalaiswamy. "A Comparative Analysis of Inductors with Square and Conical Contours." Applied Mechanics and Materials 415 (September 2013): 414–17. http://dx.doi.org/10.4028/www.scientific.net/amm.415.414.

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Winding pattern and contour are important factors in power inductors with multiple layer windings, since power inductors with multiple layers are prone to proximity effect, as multiple stacking increases the resistance stress of a conductor, eventually leading to failure of the inductor. This paper presents a comparison of winding losses for cone and square contour inductors, and discusses possible causes for the discrepancy. Conical contour inductors within a fixed core window are comparatively better than square contour winding inductors. A cross sectional analysis after winding revealed that the conical contour inductor has a gap between the conductors, indicating no melting and diffusion between layers. The absence of diffusion due to thermal degradation in conical contour winding is believed to be due to the conductor skin thickness, which is on average smaller, owing to the lower winding stresses. For a fixed dimension core and number of turns, winding losses can be reduced using a cone-shape contour compared to a square-shape contour

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22

Zhou, Junjie, Chongbo Jing, and Jianhao Liu. "On the steady posture of conical spindle distribution used in ball piston pump." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, no. 4 (December 10, 2019): 490–99. http://dx.doi.org/10.1177/1350650119893900.

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Conical spindle distribution is a new type of hydraulic pump distribution, its steady working conditions refer to a stable position of the shaft and lubrication state under constant operating condition, which directly influences the hydraulic pump efficient and reliable work. In this paper, the Reynolds equation of the tapered flow field is used to establish the lubrication model. The static pressure boundary condition of the distribution pair is obtained by the hydraulic resistance network method. The finite difference method is employed to solve the model. The static and dynamic lubricating performances including the shaft eccentricity and the distribution gap height are obtained by solving the model with a numerical method. Accordingly, the influences of structural parameters and operating parameters on the steady state are investigated, and an experimental test rig is built to validate the model. The experimental results show that the model can predict the higher working pressure which leads to higher distribution gap and eccentricity; the higher the rotational speed is, the smaller the distribution gap and the eccentricity will become, which provides theoretical support for further guidance of the distribution design.

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23

Walmsness, Per Magnus, Nathan Hale, and Morten Kildemo. "Spectroscopic Mueller matrix ellipsometry of a gap surface plasmon array at conical incidences." Journal of the Optical Society of America B 38, no. 9 (August 16, 2021): 2551. http://dx.doi.org/10.1364/josab.432466.

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24

Fang, D. H. "Stable Zero Lagrange Duality for DC Conic Programming." Journal of Applied Mathematics 2012 (2012): 1–17. http://dx.doi.org/10.1155/2012/606457.

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We consider the problems of minimizing a DC function under a cone-convex constraint and a set constraint. By using the infimal convolution of the conjugate functions, we present a new constraint qualification which completely characterizes the Farkas-type lemma and the stable zero Lagrange duality gap property for DC conical programming problems in locally convex spaces.

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25

Krestin, Evgeniy A., and Grigoriy V. Serebryakov. "Study of dynamic characteristics of flow in plane-parallel and taper clearances of drives of electric power systems." Urban construction and architecture 11, no. 4 (December 15, 2021): 169–75. http://dx.doi.org/10.17673/vestnik.2021.04.21.

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The hydrodynamic parameters of the flow of a viscous working fluid in plane-parallel and conical gaps in drives of electric power systems are investigated. A general expression is found for determining the regularity of the change in the flow rate in the gaps of non-contact seals, and special cases are considered. In the case of frictional movement of one of the walls, the Couette flow is observed in the gap. When the pressure is applied to the liquid in the gap, a parabolic velocity distribution is observed with a maximum in the middle of the channel. Under the joint action of the frictional movement of the wall and the pressure flow in the channel, stratification of fluid movement in opposite directions is observed. Frictional flow in conical slots, when the fluid moves in only one direction, is possible at a taper value of -0,5...1,0. In all other cases, the flow in the slot will have two opposite flow directions. The presence of two opposite flows inside the slot can also be for the case when the direction of movement of the movable wall coincides with the direction of the pressure flow. This is caused by an increase in pressure within the gap. A general solution has been found for the pressure force in the gaps, which tends to push the walls apart, i.e. open the sealing surfaces. The analysis of the pressure force is carried out for various cases of the slotted gap and under various effects of the frictional flow and pressure head.

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26

Rahman, Matiur, and Lokenath Debnath. "Nonlinear diffraction of water waves by offshore stuctures." International Journal of Mathematics and Mathematical Sciences 9, no. 4 (1986): 625–52. http://dx.doi.org/10.1155/s0161171286000807.

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This paper is concerned with a variational formulation of a nonaxisymmetric water wave problem. The full set of equations of motion for the problem in cylindrical polar coordinates is derived. This is followed by a review of the current knowledge on analytical theories and numerical treatments of nonlinear diffraction of water waves by offshore cylindrical structures. A brief discussion is made on water waves incident on a circular harbor with a narrow gap. Special emphasis is given to the resonance phenomenon associated with this problem. A new theoretical analysis is also presented to estimate the wave forces on large conical structures. Second-order (nonlinear) effects are included in the calculation of the wave forces on the conical structures. A list of important references is also given.

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27

Chaves, Letícia Virgínia de Freitas, Samila Neres de Oliveira, Mutlu Özcan, Wilson Acchar, Marília Regalado Galvão Rabelo Caldas, Isauremi Vieira de Assunção, Rodrigo Othávio de Assunção e. Souza, and Boniek Castillo Dutra Borges. "Interfacial Properties and Bottom/Top Hardness Ratio Produced by Bulk Fill Composites in Dentin Cavities." Brazilian Dental Journal 30, no. 5 (October 2019): 476–83. http://dx.doi.org/10.1590/0103-6440201902741.

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Abstract The aim of this study was to evaluate the bond strength, bottom/top hardness ratio, marginal adaptation, and interfacial nanoleakage of regular viscosity bulk fill composites (RVBFC) and regular viscosity traditional composites (RVTC). Two RVBFC (Filtek Bulk Fill and Aura Bulk Fill) and two RVTC (Filtek Z250XT and Aura) were assessed. Forty conical cavities (4.8×2.8×4.0) were prepared in bovine dentin and restored with composites (n=10). After 24h in water, marginal adaptation was evaluated by staining with a caries detector. The top and bottom surfaces of the conical restorations were stained for five seconds and the gap percentage in the composite/dentin interface was determined using digital images on a measurement program (ImageTool). The Vickers microhardness was measured and the bottom/top microhardness ratio (B/T) was determined. Push-out bond strength test was performed in a universal testing machine (0.5mm/min) and failure modes were evaluated in a stereomicroscope (20×). Other specimens (n=3) were produced for interfacial nanoleakage evaluation. Data were analyzed using one and two-way ANOVA and Tukey’s test (α=0.05). The gap percentage was higher in the bottom compared to the top. The B/T ratio of the Aura Bulk Fill was statistically lower than other composites. Push-out bond strength were similar among composites. The RVBFC presented lower nanoleakage than the RVTC in the bottom of the conical restoration and there was no difference among the materials in the top surfaces. In conclusion, Filtek Bulk Fill performed better than Aura Bulk Fill regarding the analyzed properties.

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28

Vijaya Sundar, J., and B. Rajakumar. "Dissociative nature of C(sp2)–N(sp3) bonds of carbazole based materials via conical intersection: simple method to predict the exciton stability of host materials for blue OLEDs: a computational study." Physical Chemistry Chemical Physics 22, no. 15 (2020): 7995–8005. http://dx.doi.org/10.1039/d0cp00221f.

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C(sp²)–N(sp³) fragmentation in OLED host materials is a fundamental property and it occurs through S0/S1 conical intersection. The kinetics of the degradation is controlled by excited state barrier height which is negatively correlated to HOMO–LUMO gap and thus provides information on the exciton stability of host materials in blue OLEDs.

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29

Husein, Nor Ain, Saktioto, Zulfadzli Yusoff, and Jalil Ali. "Slow Light in Vertically Coupled Resonator of Conical Rod Portion." Advanced Materials Research 403-408 (November 2011): 43–47. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.43.

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Resonator structures have been proposed and modified as a method of reducing the group velocity of light for optical buffering in telecommunication field. This makes the characterization and optimization of the method become important to apply. In this paper, the characterization of vertically coupler resonator is modified by investigating its geometrical parameters. The modified models with conical rod portion as the slow light structure is described where the group velocity parameters are varied. The results found that the separation gap between fibers, lg and the rod radius, a are significant in reducing the group velocity of light through such a system in the case of lossless resonators.

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Ekbåge, Daniel, Lars Nilsson, and Helena Håkansson. "Time series analysis of refining conditions and estimated pulp properties in a chemi-thermomechanical pulp process." BioResources 14, no. 3 (May 24, 2019): 5451–66. http://dx.doi.org/10.15376/biores.14.3.5451-5466.

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Frequently sampled process data from a conical disc refiner and infrequently sampled pulp data from a full scale chemi-thermomechanical pulp (CTMP) mill were evaluated to study autocovariance with aspects of potential dynamic modelling applicability. Two trial measurements with an online pulp analyzer at decreased sampling intervals were performed. For variability analysis, time-series containing up to one day of operational data were used. At the chip refiner, the clearest significant autocovariance was identified for the specific electricity consumption, based on the longer sequences. Most of the estimated pulp properties indicated low or non-significant autocovariance, limiting applicability of a specific dynamic model. A mill trial was conducted to investigate the impact from an increase in the conical disc gap on the specific electricity consumption and the resulting freeness. The response time from the gap change in the refiner to measured change in freeness was estimated at 19 min, which was approximately the hydraulic residence time in the latency chest. The relevance of this study lies in applicability of mill-data-driven modelling to capture the dynamics of a specific refining process. Through mill trials the sampling speed of pulp properties was more than doubled to gain insights into short term systematic variations by applying time-series-analysis.

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31

Teaca, Robert Stefanut, and Gheorghe Brabie. "Analysis of Geometry Deviations in Case of Conical Mini-Parts Obtained by Forming Process from Copper-Zinc Alloy (CuZn37) Sheets." Applied Mechanics and Materials 657 (October 2014): 158–62. http://dx.doi.org/10.4028/www.scientific.net/amm.657.158.

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Mini forming is an appropriate technology to manufacture small metal parts, as these are required in many industrial products resulting from mini-technology. This paper work want to underline the fact that even in down scale there are problems regarding deviation from the required dimensions. One of the problems is scaling effects, which occur in tribological aspects such as the friction coefficient, which increases with decreasing specimen size. Simulations investigations into mini forming process were carried out and mini conical parts have been obtained with different geometries. . The main objective is to observe and quantify behaviour of the mini parts during forming process and geometry deviations that affect the final product. The material used in this analysis is copper - zinc alloy with anisotropic properties. During forming process of conical mini-parts, the material record important variation along the part length and generate important shape deviation. This phenomenon causes deviations of sidewall angle, superior diameter, inferior diameter, mini part height, and connection radius between the part bottom and sidewall. There are multiple factors that affect the geometry deviations: sidewall angle, friction coefficient, tools gap, punch radius, and punch speed. The Dynaform 5.9.1 software was used to simulate the forming process. The part obtained after each simulation was analyzed and measured to quantify the deviation from the desired geometry on the final conical mini-part. In the final part of this paper some conclusions regarding geometry deviation of conical mini-parts obtained by forming are presented.

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32

Li, Xueming, Yue Chao, Rui Xie, Deji Liu, Yuanzhi Zhou, Shutong Zhang, Tian Yang, Zhanjun Liu, Lihua Cao, and Chunyang Zheng. "Enhancement of Magnetic Vortex Acceleration by Laser Interaction with Near-Critical Density Plasma inside a Hollow Conical Target." Laser and Particle Beams 2022 (February 18, 2022): 1–6. http://dx.doi.org/10.1155/2022/5671790.

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The effects of magnetic vortex acceleration (MVA) are investigated with two-dimensional particle-in-cell (PIC) simulations by laser interaction with near-critical density (NCD) plasma inside a hollow conical plasma. Energetic and collimated proton beams can be accelerated by a longitudinal charge-separation field. Energetic protons with a peak energy of 220 MeV are produced in PIC simulations. Compared with a uniform NCD plasma, both the cutoff energy and collimation of proton beams are improved remarkably. Furthermore, the influence of different gap sizes of cone tip is taken into account. For optimizing magnetic vortex acceleration, the gap size of the cone tip is suggested to match the focal spot size of laser pulse.

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33

Alonso, Alvaro, Carlos E. Prieto, Sergio Quiñonero-Salgado, and Emilio Rolán. "A morphological gap for Iberian Zospeum filled: Zospeum percostulatum sp. n. (Gastropoda, Eupulmonata, Carychiidae) a new species from Asturias (Spain)." Subterranean Biology 25 (March 15, 2018): 35–48. http://dx.doi.org/10.3897/subtbiol.25.23364.

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Zospeumpercostulatumsp. n. from Cueva de La Herrería (Llanes, Asturias) is described. It is characterized by a relatively large shell (1.4–1.8 mm height), conical, with ovate aperture, continuous peristome and thickened parietal callus; shell costulate except two first whorls; without any sort of inner formations. It is the first clearly costulate Iberian species, filling a morphological gap in the Iberian clade, and the largest species from the Cantabrian region, being the first species described from Asturias.

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34

Baskharone, E. A., and S. J. Hensel. "Interrelated Rotordynamic Effects of Cylindrical and Conical Whirl of Annular Seal Rotors." Journal of Tribology 113, no. 3 (July 1, 1991): 470–80. http://dx.doi.org/10.1115/1.2920648.

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A comprehensive approach for computing the dynamic coefficients of an annular seal is presented. The coefficients are partly those associated with a uniform lateral eccentricity mode of the rotor (known as the cylindrical whirl mode) and with an angular eccentricity (which gives rise to a conical whirl type). The rotor excitation effects in both cases are treated as interrelated by recognizing the fluid-exerted moments resulting from the lateral eccentricity and the net fluid force resulting from the angular eccentricity. In all cases, the rotor is assumed to undergo a whirling motion around the housing centerline. The computational procedure is a finite-element perturbation model in which the zeroth-order undisplaced-rotor flow solution in the clearance gap is obtained through a Petrov-Galerkin approach. Next, the rotor translational and angular eccentricities, considered to be infinitesimally small, are perceived to cause virtual distortions of varied magnitudes in the finite element assembly which occupies the clearance gap. Perturbations in the flow variables including, in particular, the rotor surface pressure, are then obtained by expanding the finite-element equations in terms of the rotor eccentricity components. The fluid-exerted forces and moments are in this case computed by integration over the rotor surface, and the full matrix of rotordynamic coefficients, in the end, obtained. The computational model is verified against a bulk-flow model for a sample case involving a straight annular seal. Choice of this sample model for validation was made on the basis that no other existing model has yet been expanded to account for the mutual interaction between the cylindrical and conical rotor whirl, which is under focus in this study.

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35

Gat, A. D., H. K. Navaz, and M. Gharib. "Wicking of a liquid bridge connected to a moving porous surface." Journal of Fluid Mechanics 703 (June 12, 2012): 315–25. http://dx.doi.org/10.1017/jfm.2012.218.

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AbstractWe study the coupled problem of a liquid bridge connected to a porous surface and an impermeable surface, where the gap between the surfaces is an externally controlled function of time. The relative motion between the surfaces influences the pressure distribution and geometry of the liquid bridge, thus affecting the shape of liquid penetration into the porous material. Utilizing the lubrication approximation and Darcy’s phenomenological law, we obtain an implicit integral relation between the relative motion between the surfaces and the shape of liquid penetration. A method to control the shape of liquid penetration is suggested and illustrated for the case of conical penetration shapes with an arbitrary cone opening angle. We obtain explicit analytic expressions for the case of constant relative speed of the surfaces as well as for the relative motion between the surfaces required to create conical penetration shapes. Our theoretical results are compared with experiments and reasonable agreement between the analytical and experimental data is observed.

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36

Torres, Baltasar, Joaquín Abolafia, Reyes Peña-Santiago, and Gracia Liébanas. "Nematodes of the order Dorylaimida from Andalucía Oriental, Spain: Discolaimus Cobb, 1913. 1. Description of two new species." Nematology 4, no. 3 (2002): 361–69. http://dx.doi.org/10.1163/156854102760199196.

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AbstractTwo new species of the genus Discolaimus Cobb, 1913 are described from southeastern Spain. D. mariae sp. n. is distinguished by its large size (L = 2.4-3.3 mm), lip region diameter 29-35 μm, odontostyle 23-25 μm, pharyngeal expansion occupying two-thirds of the total neck length, presence of dorsal cell bodies close to cardia, V = 46-53, female genital system didelphicamphidelphic, tail conical with rounded terminus (33-39 μm, c = 72-88, c′ = 0.9-1.0) and with a terminal gap in the inner cuticle, and males absent. D. labiatus sp. n. is characterised by being medium sized (L = 0.99-1.20 mm), lip region diameter 14-17 μm wide, labial disc with no radial but six longitudinal grooves, inner (perioral) labial portion forming well developed liplets, odontostyle 10.0-12.5 μm, vulva relatively anterior (V = 39-43), female tail conical with rounded terminus (26-27 μm, c = 37-46, c′ = 1.5-1.7), and male unknown. Scanning electron microscope observations of the species are also presented.

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37

Han, Rui, and Jinju Chen. "A modified Sneddon model for the contact between conical indenters and spherical samples." Journal of Materials Research 36, no. 8 (April 28, 2021): 1762–71. http://dx.doi.org/10.1557/s43578-021-00206-5.

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AbstractIndentation techniques have proven to be effective to characterize the mechanical properties of materials. For the elastic deformation, the commonly used models are Hertz model and Sneddon model. However, neither of them works for indenting the spherical samples using the pyramid or conical indenter. Therefore, one modified Sneddon model has been developed to determine the Young’s modulus of spherical samples from indentation results. In this study, the effects of sample diameter and indenter angles on indentation tests were investigated by finite element method (FEM). The empirical correction parameters in the new mathematical model were introduced based on dimensional analysis and determined by the numerical fitting to FEM results. Experimental tests with different conical indenters have demonstrated that the new model is capable to reliably determine the Young’s modulus of the spherical samples. The new model can fill the gap of the contact mechanics and enrich the experimental solid mechanics for the interpretation of indentation results. Graphic abstract

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38

Xia, Yingxiang, Xuedao Shu, Ying Zhu, and Zixuan Li. "Influence of Process Parameters on Forming Load of Variable-Section Thin-Walled Conical Parts in Spinning." Applied Sciences 10, no. 17 (August 27, 2020): 5932. http://dx.doi.org/10.3390/app10175932.

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Thin-walled conical parts with variable-section are usually made of superalloy material, with poor plasticity and complex forces, which are difficult to form and control. In this research, a thin-walled conical casing of superalloy GH1140 with variable-section is studied; the real stress–strain curve of the material is fitted and the load-displacement curves of superalloy GH1140 are obtained through a universal testing machine. To clarify the equivalent stress distribution on the upper surface of the thin-walled casing during the forming process and after unloading the rotary wheel, the finite element model of the thin-walled conical casing during the spinning forming process is established with the Simufact Forming finite element analysis software. The effects of processing parameters, such as the mandrel rotational speed ω, the roller feed ratio f and the gap deviation rate δ between the roller and mandrel, on the spinning forming load were obtained. The distribution and numerical trend of the tangential residual stress after forming were detected by X-ray diffraction, and the causes of defects such as flange instability were analyzed. The results of the forming test and the test of residual stress conform well with the simulation, which verifies the stability of the model. The research provides a theoretical basis for improving the forming quality of thin-walled parts with variable-section.

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39

Jiries, Yousef, Tamar Brosh, Shlomo Matalon, Vladimir Perlis, and Zeev Ormianer. "Effects of Aging Torque Controllers on Screw Tightening Force and Bacterial Micro-Leakage on the Implant-Abutment Complex." Materials 15, no. 2 (January 14, 2022): 620. http://dx.doi.org/10.3390/ma15020620.

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Aim: We assess the accuracy of torque controllers after several aging processes and the bacterial leakage on implant-abutment complexes (IAC). Methods: A total of 12 spring-type and 12 friction-type torque controllers and 48 IAC (24 conical and 24 hexagonal connections) were evaluated. Chemical, mechanical, temperature, and pressure-aging methods were applied individually to replicate clinical use. Torque controller accuracy was analyzed before and after aging using a calibrated gauge. To assess bacterial leakage, the IAC were suspended in a bacterial medium for 24 h. Direct Contact Test (DCT) and Polymerase Chain Reaction Test (RT-PCR) analyzed the infiltration of F. nucleatum and P. gingivalis into the IAC micro-gap. Results: A significant decrease in torque after 10 days of aging was found. The spring-type torque controller was affected the most, regardless of the aging method (P < 0.05). PCR results indicated that all groups exhibited significantly more bacterial leakage, regardless of the method used (P < 0.05). The conical IAC demonstrated more bacterial leakage of P. gingivalis compared with the hexagonal IAC (P = 0.07). DCT found bacterial growth in the IAC only before aging and was not identified after aging. Conclusion: Aging affects torque accuracy. A reduction in force was noticed after 10 days. The conical IAC exhibits more bacterial leakage, although this was not statistically significant.

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40

Tugendhaft, I., A. Bornstein, Y. Weissman, and A. Hardy. "Coupling Efficiency of Directional Fiber Couplers in the Mid-Infrared." Applied Spectroscopy 50, no. 7 (July 1996): 906–9. http://dx.doi.org/10.1366/0003702963905420.

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Coupling efficiency characterization in the mid-IR region (2–10 μm) of contact couplers made of step index multimode As2Se3 fiber is given. A unique setup based on an FT-IR spectrometer was built to measure this parameter in several couplers. It is observed that the coupling efficiency between the coupled and the direct output arms increases linearly with the interaction length and monotonously with the wavelength in the mid-IR region. A coupling ratio of almost 20% at 10 μm has been achieved with an interaction length of 120 mm, while the conical input beam has a 40° opening angle. A theoretical model connecting the coupling efficiency and the coupler's gap is introduced. A comparison between this model and the observations yields an effective gap value of about 40 nm.

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Slătineanu, Laurenţiu, Margareta Coteaţă, Lorelei Gherman, Irina Beşliu, Miroslav Radovanović, Ciprian Mircescu, and Stefan Ştoica. "Diminishing Shape Errors at Electrical Discharge Machining of External Cylindrical Surfaces." Applied Mechanics and Materials 371 (August 2013): 305–9. http://dx.doi.org/10.4028/www.scientific.net/amm.371.305.

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Electrical discharge machining is a method that could be applied in order to detach cylindrical parts from a workpiece made of electroconductive material. If cylindrical tube is used as tool electrode, the machined surface could have a conical shape, due to the presence in the work gap of the electroconductive particles, detached from electrodes. Experimental researches were developed in order to obtain information concerning the shape error of machined surface. As a result of the experimental observation, improved technological solutions were identified and investigated. The experimental results proved certain possibilities of shape error decrease.

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GONZALEZ-AVILA, SILVESTRE ROBERTO, EVERT KLASEBOER, BOO CHEONG KHOO, and CLAUS-DIETER OHL. "Cavitation bubble dynamics in a liquid gap of variable height." Journal of Fluid Mechanics 682 (June 21, 2011): 241–60. http://dx.doi.org/10.1017/jfm.2011.212.

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We report on an experimental study of cavitation bubble dynamics within sub-millimetre-sized narrow gaps. The gap height is varied, while the position of the cavitation event is fixed with respect to the lower gap wall. Four different sizes of laser-induced cavitation bubbles are studied using high-speed photography of up to 430,000 frames per second. We find a strong influence of the gap height, H, on the bubble dynamics, in particular on the collapse scenario. Also, similar bubble dynamics was found for the same non-dimensional gap height η = H/Rx, where Rx is the maximum radius in the horizontal direction. Three scenarios are observed: neutral collapse at the gap centre, collapse onto the lower wall and collapse onto the upper wall. For intermediate gap height the bubble obtains a conical shape 1.4 < η < 7.0. For large distances, η > 7.0, the bubble no longer feels the presence of the upper wall and collapses hemispherically. The collapse time increases with respect to the expansion time for decreasing values of η. Due to the small scales involved, the final stage of the bubble collapse could not be resolved temporally and numerical simulations were performed to elucidate the details of the flow. The simulations demonstrate high-speed jetting towards the upper and lower walls and complex bubble splitting for neutral collapses.

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43

Chen, Yan, and Li Bao An. "Simulation of Electric Field for Carbon Nanotube Assembly by Dielectrophoresis." Advanced Materials Research 941-944 (June 2014): 421–24. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.421.

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In the process of carbon nanotube assembly by dielectrophoresis, the geometry and spacing of electrodes are significantly affecting the assembly precision. In the simulation process, we showed the geometrical shape of conical, round and rectangular electrode and compared the electric field distribution with these electrodes. Compared with single electrode pairs, comb electrodes can achieve high-yield manipulation. Simulation results show that when the distance between adjacent electrode pairs is larger than twice electrode width, it will avoid electric field superimposition. A method of using floating metal posts within the electrode gap can realize precise positioning of assembled carbon nanotubes.

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CZABAN, Adam. "CFD ANALYSIS OF THE HYDRODYNAMIC LUBRICATION OF A MISALIGNED, SLIDE CONICAL BEARING." Tribologia 268, no. 4 (August 31, 2016): 41–53. http://dx.doi.org/10.5604/01.3001.0010.6977.

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The lateral loads carried by hydrodynamic bearings, and also their uneven distribution, introduce an additional axial misalignment between the shaft and sleeve. The machining and mounting errors also result in improper initial alignment of bearing shaft or sleeve. Furthermore, due to vibrations, misalignment of shaft fluctuates during the operation of the bearing. This has an impact on the operating parameters of the bearing, and, in extreme cases, where the maximum allowable value of the misalignment is exceeded, the bearing can be damaged. The aim of this work is to investigate the effect of misalignment on the hydrodynamic pressure distribution in the conical sliding bearing lubrication gap and on the bearing load carrying capacity and friction force values. This paper shows the result of a CFD simulation of hydrodynamic conical bearings lubrication with the assumption that the bearings are misaligned, i.e. where the rotation axis of bearing shaft is not parallel to the axis of the cone of the bearing sleeve. The commercial CFD software ANSYS Fluent was used in this research. It was assumed that the flow of lubricating oil is laminar, without slipping on bearing surfaces, and that the oil has non-Newtonian properties.

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45

Czaban, Adam, and Andrzej Miszczak. "Simulations of the Influence of the Heat Flux at the Shaft Surface of the Conical Slide Bearing on Its Hydrodynamic Lubrication and Operating Parameters." Journal of KONES 26, no. 4 (December 1, 2019): 29–37. http://dx.doi.org/10.2478/kones-2019-0086.

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AbstractThe aim of this work is to investigate, how in the adopted model of hydrodynamic lubrication of a conical slide bearing, the change of the heat flux value at the bearing shaft, affects bearing operating parameters. In this research, the authors use, the known from the literature, Reynolds type equation, describing the stationary hydrodynamic lubrication process of a conical slide bearing. The analytical, solutions, that determine the components of the lubricating oil velocity vector and the equation (analytical solution of energy equation) determining the three-dimensional temperature distribution in the lubrication gap, was also adopted from previous works. In order to obtain numerical solutions, the Newton’s method was used, and the derivatives in the Reynolds type equation were approximated by the finite differences. An application of the method of subsequent approximations allowed considering the influence of temperature, pressure and shearing rate on the viscosity of lubricating oil. The considerations were performed by adopting the Reynolds condition of the hydrodynamic oil film. It was tested, how the assumed value of the heat flux on the bearing shaft surface affects the values of the obtained operating parameters, i.e. the transverse and longitudinal component of the load carrying capacity, friction force and coefficient of friction.

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46

Kovaleva, Natalia, Ladislav Fekete, Dagmar Chvostova, and Andrei Muratov. "Morphology and Optical Properties of Thin Cd3As2 Films of a Dirac Semimetal Compound." Metals 10, no. 10 (October 21, 2020): 1398. http://dx.doi.org/10.3390/met10101398.

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Using atomic-force microscopy (AFM) and wide-band (0.02–8.5 eV) spectroscopic ellipsometry techniques, we investigated the morphology and optical properties of Cd3As2 films grown by non-reactive RF magnetron sputtering on two types of oriented crystalline substrates (100)p-Si and (001) α-Al2O3. The AFM study revealed the grainy morphology of the films due to island incorporation during the film growth. The complex dielectric function spectra of the annealed Cd3As2/Al2O3 films manifest pronounced interband optical transitions at 1.2 and 3.0 eV, in excellent agreement with the theoretical calculations for the body centered tetragonal Cd3As2 crystal structure. We discovered that due to electronic excitations to the Cd(s) conical bands, the low-energy absorption edge of the annealed Cd3As2 films reveals a linear dependence. We found that for the annealed Cd3As2 films, the Cd(s) conical node may be shifted in energy by about 0.08–0.18 eV above the heavy-flat As(p) valence band, determining the optical gap value. The as-grown Cd3As2 films exhibit the pronounced changes of the electronic band structure due to the doping effect associated with Cd non-stoichiometry, where fine-tuning of the Cd concentration may result in the gapless electronic band structure of Dirac semimetals.

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47

Hassan, Ahmed T., Ehssan S. Hassan, and Oday M. Abdulmunem. "Effect of thermal annealing on the structural and optical properties of TiO₂ nanostructures^**." Journal of the Mechanical Behavior of Materials 30, no. 1 (January 1, 2021): 304–8. http://dx.doi.org/10.1515/jmbm-2021-0033.

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Abstract In this work, TiO nanostructure films were deposited via vacuum thermal evaporation at a temperature of 80°C. The TiO thin films were annealed under vacuum for 1 h at three different degrees (200, 300, and 400°C) in addition to the thin film prepared at 80°C. X-ray Diffraction (XRD) showed that all the deposited and annealed TiO films had anatase polycrystalline diffraction patterns with a predominant reflection of the (200) plane. As a result, the particle size increased with annealing temperature. Scanning Electron Microscopy (SEM) measurements showed that at the annealed temperature of 200°C, the shape of the TiO nanostructures began to change from a condensed cluster distribution to a conical shape. As the annealing temperature was increased to 400°C, all the conical shapes transformed into clear spherical shapes. The spherical shapes recorded 45 (nm) height and (20) (nm) base width. Optical measurements were performed using Ultraviolet-Visible spectroscopy (UV-Vis). The transmittance is reduced from 79.63% for the TiO sample prepared at 80°C to 71.91% for the TiO sample annealed at 400°C. The optical energy gap values decrease from 3.279 eV for the prepared TiO sample at 80°C to 3.115 eV for the TiO sample annealed at 400°C.

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48

ALONSO, F., N. JURISTO, and J. PAZOS. "TRENDS IN LIFE-CYCLE MODELS FOR SE AND KE: PROPOSAL FOR A SPIRAL-CONICAL LIFE-CYCLE APPROACH." International Journal of Software Engineering and Knowledge Engineering 05, no. 03 (September 1995): 445–65. http://dx.doi.org/10.1142/s0218194095000228.

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The ten-year gap between the emergence of Software Engineering (SE) and Knowledge Engineering (KE) has led to the two disciplines developing along different methodological lines. In this paper, we point out that, after having passed through a period during which they ignored each other, followed by a competitive phase, the two disciplines have now reached a meeting point. We see the need for a life-cycle model for systems that integrate traditional and knowledge-based software. Besides, software development in the 21st century will entail open requirements and technological tools that will evolve during the life-cycle. Finally, the paper discusses a proposal for a conical-type spiral life-cycle model that seeks to meet all those needs.

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49

Qin, Wei, Ira M. Cohen, and P. S. Ayyaswamy. "Fixed Wand Electronic Flame-Off for Ball Formation in the Wire Bonding Process." Journal of Electronic Packaging 116, no. 3 (September 1, 1994): 212–19. http://dx.doi.org/10.1115/1.2905688.

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In the latest generation of wire bonders, the cycle is so short that the wand electrode is kept stationary and the electronic flame off (EFO) discharge is from the side of the wire. This is the discharge that heats and melts the wire causing roll up into a ball that is pressed down onto the chip to form a ball bond. The balls must be perfectly formed with defects in the few ppm range. In the first part of the paper, the fixed, conically shaped side wand and the improved ring wand design are studied by considering the electrostatic field before the breakdown. In the second part of the paper, discharge development starting from the initial electrostatic field between a wire and a ring wand up to the breakdown, and ionization growth in the gap between the electrodes are both examined by numerical simulations. In the computations, the conservation equations for ions and electrons and Poisson’s equation have been employed for the self-consistent electric field. Based on sensitivity to wire length and wire deflection, the results show that the ring wand is a better design than the conical side wand electrode for ball formation and wire bonding. Also, positive wire polarity is preferred over negative wire polarity.

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50

MacArthur, Sandra L., Matthew D. Johnson, and Daniel D. Lewis. "Biomechanical Comparison of Two Conical Coupling Plate Constructs for Cat Tibial Fracture Stabilization." Veterinary and Comparative Orthopaedics and Traumatology 33, no. 04 (April 21, 2020): 252–57. http://dx.doi.org/10.1055/s-0040-1708497.

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Abstract Objective This study aimed to compare the biomechanical characteristics of two conical coupling plate (CCP) constructs in an ex vivo feline tibial fracture gap model. Study Design Paired tibiae harvested from eight recently euthanatized cats were alternately assigned to one of two stabilization groups. One tibia was stabilized with a standard, 6-hole, 2.5-mm CCP and the contralateral tibia was stabilized with a 6-hole, 2.5-mm prototype CCP (pCCP). Non-destructive cyclic four-point craniocaudal bending, mediolateral bending and axial compression testing were performed, and stiffness was recorded. The specimens were then loaded to failure in axial compression, and yield and failure loads were recorded. Results During non-destructive testing, the pCCP constructs were significantly stiffer than the CCP constructs in both modes of bending and axial loading. Both constructs demonstrated significantly greater craniocaudal bending stiffness compared with mediolateral bending. Yield load and failure load were significantly greater for the pCCP constructs. Conclusion The augmented design of the pCCP yielded superior mechanical characteristics during both non-destructive and destructive testings compared with constructs employing standard CCP. The more rigid design of the pCCP suggests that this implant may be better at withstanding greater loads, particularly when applied in a bridging fashion, during the postoperative convalescence. Further investigations are warranted to prospectively evaluate the clinical performance of the pCCP.

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