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Journal articles on the topic 'Cylindrical estimates'

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Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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1

Becker, Fabian, and Christian Hopmann. "Stiffness Estimates for Composites with Elliptic Cylindrical Voids." Materials 13, no. 6 (March 17, 2020): 1354. http://dx.doi.org/10.3390/ma13061354.

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A two-step homogenization procedure is presented to investigate the stiffness of a unidirectional continuous fiber-reinforced composite material containing voids of different shapes and volume contents. Since the Mori–Tanaka scheme is limited to moderate volume contents of the inhomogeneity phase, fiber and matrix are homogenized with semi-empirical relations with use of the adjusted fiber volume content in a first step. In the second step, the Mori–Tanaka scheme is applied to obtain the homogenized stiffness tensor of a transversely isotropic material containing voids aligned with the fiber direction. The voids are modelled with infinite length, but an elliptic base characterized by the aspect ratio. The tensor components of the Eshelby tensor for this case are presented in closed form for a transversely isotropic material depending on the aspect ratio and matrix material properties. The scheme is solved directly for easy implementation and the use of fast calculations of the effective engineering constants of a composite material containing voids. Experimental results from literature for different void contents and shapes are compared to the predicted moduli with cylindrical voids. From the results it is further concluded that the aspect ratio of the void and the manufacturing process of the composite should be considered.

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2

Abe, Ken, Yoshikazu Giga, Katharina Schade, and Takuya Suzuki. "On the Stokes resolvent estimates for cylindrical domains." Journal of Evolution Equations 17, no. 1 (September 6, 2016): 17–49. http://dx.doi.org/10.1007/s00028-016-0350-6.

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3

Andrews, Ben, and Mat Langford. "Cylindrical estimates for hypersurfaces moving by convex curvature functions." Analysis & PDE 7, no. 5 (September 27, 2014): 1091–107. http://dx.doi.org/10.2140/apde.2014.7.1091.

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4

Ji, Zhengchao. "Cylindrical estimates for mean curvature flow in hyperbolic spaces." Communications on Pure & Applied Analysis 20, no. 3 (2021): 1199. http://dx.doi.org/10.3934/cpaa.2021016.

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5

Langford, Mat, and Stephen Lynch. "Sharp one-sided curvature estimates for fully nonlinear curvature flows and applications to ancient solutions." Journal für die reine und angewandte Mathematik (Crelles Journal) 2020, no. 765 (August 1, 2020): 1–33. http://dx.doi.org/10.1515/crelle-2019-0010.

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AbstractWe prove several sharp one-sided pinching estimates for immersed and embedded hypersurfaces evolving by various fully nonlinear, one-homogeneous curvature flows by the method of Stampacchia iteration. These include sharp estimates for the largest principal curvature and the inscribed curvature (“cylindrical estimates”) for flows by concave speeds and a sharp estimate for the exscribed curvature for flows by convex speeds. Making use of a recent idea of Huisken and Sinestrari, we then obtain corresponding estimates for ancient solutions. In particular, this leads to various characterisations of the shrinking sphere amongst ancient solutions of these flows.

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6

Pipoli, Giuseppe, and Carlo Sinestrari. "Cylindrical estimates for mean curvature flow of hypersurfaces in CROSSes." Annals of Global Analysis and Geometry 51, no. 2 (September 29, 2016): 179–88. http://dx.doi.org/10.1007/s10455-016-9530-4.

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7

Gavrilenko, G. D., A. S. Sitnik, and V. I. Matsner. "On lower-bound estimates of critical loads for cylindrical shells." International Applied Mechanics 42, no. 10 (October 2006): 1145–50. http://dx.doi.org/10.1007/s10778-006-0186-9.

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8

Osakue, Edward E., and Lucky Anetor. "Revised Lewis Bending Stress Capacity Model." Open Mechanical Engineering Journal 14, no. 1 (July 31, 2020): 1–14. http://dx.doi.org/10.2174/1874155x02014010001.

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Background: During operation, cylindrical gearset experiences tangential, radial, and axial (helical gears only) force components that induce bending, compressive, and shear stresses at the root area of the gear tooth. Accurate estimation of the effective bending stress at the gear root is a challenge. Lewis was the first person who attempted estimating the root bending stress of spur gears with some reasonable accuracy. Various gear standards and codes in use today are modifications and improvements of the Lewis model. Objective: This research aims at revising the Lewis model by making adjustments for dynamic loads, shear stresses, axial bending stress for helical gears, and stress concentration factor that is independent on the moment arm of tangential or axial force component. Methods: An analytical approach is used in formulating a modified formula for the root bending stress in cylindrical gears starting with the original Lewis model. Intermediate expressions are developed in the process and works from many previous authors are reviewed and summarized. The new model developed is used to estimate the root bending stress in four example gearsets of 0o to 41.41o helix angle and the results are compared with those of AGMA (American Gear Manufacturers Association) formula. Results: Analysis from the examples shows that neglecting the radial compressive stress over-estimated the root bending stress by 5.27% on average. When shear stresses are ignored, the root bending stress is under-estimated by 7.49% on average. It is important, therefore, to account for both compressive and shear stresses in cylindrical gear root bending stress. When the root bending stress estimates from the revised Lewis model were compared with AGMA results, deviations in the range of -4.86% to 26.61% were observed. The stress estimates from the revised Lewis formulae were mostly higher than those of AGMA. Conclusion: The new root bending stress model uses stress concentration factors (normal and shear) that are independent of the point of load application on the gear tooth. This decoupling of stress concentration factor from the load moment arm distinguishes the new model from AGMA formula and brings bending stress analysis in gear design in line with classical bending stress analysis of straight and curved beams. The model can be used for both normal contact ratio and high contact ratio cylindrical gears.

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9

CHRISTIANSEN, Tanya J., and Kiril DATCHEV. "Resolvent estimates on asymptotically cylindrical manifolds and on the half line." Annales scientifiques de l'École Normale Supérieure 54, no. 4 (2021): 1051–88. http://dx.doi.org/10.24033/asens.2477.

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10

Nguyen, Huy The. "Convexity and cylindrical estimates for mean curvature flow in the sphere." Transactions of the American Mathematical Society 367, no. 7 (March 4, 2015): 4517–36. http://dx.doi.org/10.1090/s0002-9947-2015-05927-3.

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11

Veiga, L. Beir�o da. "Uniform error estimates for a class of intermediate cylindrical shell problems." Numerische Mathematik 96, no. 4 (February 1, 2004): 661–89. http://dx.doi.org/10.1007/s00211-003-0484-7.

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12

Wang, Guibao, Haihong Tao, Lanmei Wang, and Cao Zeng. "Joint Estimation of DOA and Polarization with CLD Pair Cylindrical Array Based on Quaternion Model." Mathematical Problems in Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/806853.

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This paper proposes a quaternion-ESPRIT algorithm for closed-form estimation of direction of arrival (DOA) and polarization, using a cylindrical conformal array configuration. First, the array steering vector and the elevation are estimated using a quaternion eigenvalue decomposition of the data covariance matrix. Second, the azimuth is estimated. Finally, the polarization parameters are estimated using the relationships between the dipoles and the loops. These estimates are automatically matched. Simulation results show that the performance of quaternion method is obviously better than that of the long-vector method.

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13

Liu, Chao, and Shunian Yin. "An Efficient 2-D DOA Estimation for a Cylindrical Conformal Array with Unknown Mutual Coupling." International Journal of Antennas and Propagation 2018 (October 4, 2018): 1–8. http://dx.doi.org/10.1155/2018/4015980.

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The limited space of a conformal array may lead to a serious mutual coupling effect, which will significantly affect the performance of direction of arrival (DOA) estimation algorithms. In this paper, an efficient 2-D direction finding method is developed in the presence of unknown mutual coupling for the uniform cylindrical conformal array (CCA). To avoid the time-consuming two-dimensional spectral peak searching, the 2-D DOA estimation is decoupled and divided into two 1-D DOA estimations. Elevation is first estimated based on a subarray estimation of signal parameters via rotation invariant technique (ESPRIT), and then azimuth is estimated based on the rank reduction (RARE) method by using the elevation estimation result. Consequently, the mutual coupling coefficients can be estimated after getting the DOA estimates. The proposed method can well calibrate the mutual coupling effect of a cylindrical array with a low computational complexity. The final simulation results corroborate our analysis.

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14

Wang, Jian. "Linear Evolution Equations with Cylindrical Lévy Noise: Gradient Estimates and Exponential Ergodicity." Stochastic Analysis and Applications 33, no. 2 (February 2, 2015): 306–30. http://dx.doi.org/10.1080/07362994.2014.989330.

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15

Calvo, David C., Mario Zampolli, and Alessandra Tesei. "Estimates of scattering strength for buried cylindrical targets ensonified by evanescent waves." Journal of the Acoustical Society of America 123, no. 5 (May 2008): 3947. http://dx.doi.org/10.1121/1.2936045.

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16

Thompson, V. K. "Elastic buckling of double walled cylindrical storage tanks—numerical and analytical estimates." Computers & Structures 23, no. 3 (January 1986): 451–55. http://dx.doi.org/10.1016/0045-7949(86)90235-x.

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17

Lynch, Thomas B., Shen-Then Chang, and John P. Chandler. "Estimation of individual tree volume by importance sampling and antithetic variates from the cylindrical shells integral." Canadian Journal of Forest Research 22, no. 3 (March 1, 1992): 326–35. http://dx.doi.org/10.1139/x92-042.

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A method of estimating individual tree volume by importance sampling is developed that is based on the cylindrical shells volume integral. The cylindrical shells volume integral conceptualizes a tree stem as being a solid of revolution comprising a collection of thin cylinders. Previous applications of importance sampling to individual tree volume estimation have been based on the method of slices integral, in which the tree stem is viewed as a solid of revolution comprising a collection of thin disks. Both approaches provide unbiased estimates of individual tree volume for any monotonic tree taper, if it can be assumed that the tree is circular in cross section. An advantage of the cylindrical shells approach is that total tree height need not be measured to accomplish the estimation process, as would be required when using importance sampling estimators based on the method of slices integral. Tree volume estimation via importance sampling based on the cylindrical shells integral requires measurement of stump cross-sectional area, which is usually more easily obtained than total or merchantable height measurements. Both approaches require one or more upper stem diameter measurements. Computer simulation shows that use of antithetic variates with importance sampling reduces the variance of the volume estimate significantly when a paraboloid is used as a proxy taper function.

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18

Tschudin, Marcel E., and Steven R. Schroeder. "Time Constant Estimates for Radiosonde Temperature Sensors." Journal of Atmospheric and Oceanic Technology 30, no. 1 (January 1, 2013): 40–56. http://dx.doi.org/10.1175/jtech-d-11-00181.1.

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Abstract To correct time lag errors in radiosonde temperatures the sensor time constant has to be known. Time constants are not published for some widely used sensors and, in some cases, available time constants disagree. This study focuses on ML-405, ML-419, VIZ/Sippican Mark II Microsonde and B2, Russian MMT-1, and Chinese GZZ-7 rod thermistors. It measures still air time constants and heat capacities and derives theoretical still air and aerated time constants based on heat transfer involving nonuniform cylinders. With low aeration, such as in the stratosphere, heat conduction by lead wires from the thermistor noticeably shortens the time constant. Some discrepancies in published time constants are explained by researchers not considering the temperature dependence of all relevant variables. Empirical formulas are derived to estimate the aerated time constant of cylindrical temperature sensors based on dimensions. The aerated time constant in soundings is found to be about 6 times as long at 10 hPa as near sea level.

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19

Lin, Jinxing, D. A. Sampson, G. Deckmyn, and R. Ceulemans. "Significant overestimation of needle surface area estimates based on needle dimensions in Scots pine (Pinus sylvestris)." Canadian Journal of Botany 80, no. 9 (September 1, 2002): 927–32. http://dx.doi.org/10.1139/b02-081.

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Needle length and width at midpoint are often used to make estimates of needle surface area for conifers. For these estimates, Scots pine (Pinus sylvestris L.) fascicles are assumed to be cylindrical; thus, for a two-needle pine, the cross section of a needle within the fascicle is assumed to be hemicylindrical. The objectives of this study were to determine whether these assumptions lead to a good estimate of the actual surface area and how needles vary with tree age and crown position. We used a digital scanning microscope to measure needle width, thickness, and perimeter at 11 positions along 28 needles from different crown positions in different-aged trees and found that they varied with position within the individual needle as well as with tree age and crown position. Needle shape was relatively constant: needle width and perimeter both increased from the base to the needle midpoint and then decreased slightly to the needle tip, but needles were not hemicylindrical and actual perimeters were nearly 12% larger than predicted perimeters. The predicted surface areas based on measurements of width at the needle midpoint and length need to be reduced by 9% to account for the fact that needles taper and are not cylindrical. Furthermore, tree age and crown position must be considered when crown-level estimates are made.Key words: digital image analyzer, light microscope, needle width, needle thickness, needle perimeter, Pinus sylvestris.

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20

Rivera-Noriega, Jorge. "Absolute continuity of parabolic measure and area integral estimates in non-cylindrical domains." Indiana University Mathematics Journal 52, no. 2 (2003): 475–524. http://dx.doi.org/10.1512/iumj.2003.52.2210.

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21

Ped’, S. E., and E. V. Darienko. "Error estimates in coordinate measurements of the cross section parameters of cylindrical surfaces." Measurement Techniques 54, no. 8 (November 2011): 874–78. http://dx.doi.org/10.1007/s11018-011-9820-y.

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22

Li, Long-Yuan. "Approximate estimates of dynamic instability of long circular cylindrical shells under pure bending." International Journal of Pressure Vessels and Piping 67, no. 1 (June 1996): 37–40. http://dx.doi.org/10.1016/0308-0161(94)00073-5.

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23

Meas, Len. "Dispersive estimates for the wave equation inside cylindrical convex domains: A model case." Comptes Rendus Mathematique 355, no. 2 (February 2017): 161–65. http://dx.doi.org/10.1016/j.crma.2017.01.005.

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24

Weng, Shangkun, Zhouping Xin, and Hongwei Yuan. "On some smooth symmetric transonic flows with nonzero angular velocity and vorticity." Mathematical Models and Methods in Applied Sciences 31, no. 13 (October 30, 2021): 2773–817. http://dx.doi.org/10.1142/s0218202521500615.

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This paper concerns the structural stability of smooth cylindrically symmetric transonic flows in a concentric cylinder. Both cylindrical and axi-symmetric perturbations are considered. The governing system here is of mixed elliptic–hyperbolic and changes type and the suitable formulation of boundary conditions at the boundaries is of great importance. First, we establish the existence and uniqueness of smooth cylindrical transonic spiral solutions with nonzero angular velocity and vorticity which are close to the background transonic flow with small perturbations of the Bernoulli’s function and the entropy at the outer cylinder and the flow angles at both the inner and outer cylinders independent of the symmetric axis, and it is shown that in this case, the sonic points of the flow are nonexceptional and noncharacteristically degenerate, and form a cylindrical surface. Second, we also prove the existence and uniqueness of axi-symmetric smooth transonic rotational flows which are adjacent to the background transonic flow, whose sonic points form an axi-symmetric surface. The key elements in our analysis are to utilize the deformation-curl decomposition for the steady Euler system to deal with the hyperbolicity in subsonic regions and to find an appropriate multiplier for the linearized second-order mixed type equations which are crucial to identify the suitable boundary conditions and to yield the important basic energy estimates.

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25

Fisher, C. E., and K. S. Ball. "Plume Dynamics in Natural Convection in a Horizontal Cylindrical Annulus." Journal of Heat Transfer 121, no. 3 (August 1, 1999): 598–602. http://dx.doi.org/10.1115/1.2826021.

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Measurements of the unsteady temperature fluctuations in the plume region between differentially heated horizontal concentric cylinders are reported. In particular, power spectral density estimates of the temperature fluctuations within the plume show the development and breakdown of the oscillatory plume structure at high Rayleigh number, Rad, by two relatively independent processes: (1) the development of harmonic oscillations related to the dominant plume oscillation frequency, and (2) interactions between the oscillating plume and the adjacent relatively stagnant core flow (shear and entrainment). The harmonic oscillations are shown to be the dominant energy transfer mode at moderate Rad (up to Rad = 108), acting to disperse the plume energy without generating a broadband spectrum. The spectral density estimates show that while a distinct plume oscillation is still present near the inner cylinder at Rad = 109, the plume becomes increasingly turbulent as the outer cylinder is approached. A new correlation for the plume oscillation frequency, which is found to be proportional to Rad0.5, is also presented.

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26

Kulczycki, Tadeusz, and Michal Ryznar. "Transition density estimates for diagonal systems of SDEs driven by cylindrical alpha-stable processes." Latin American Journal of Probability and Mathematical Statistics 15, no. 2 (2018): 1335. http://dx.doi.org/10.30757/alea.v15-50.

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27

Tryamkin, M. V. "Modulus Estimates on Abstract Surfaces over a Domain of Revolution and a Cylindrical Ring." Mathematical Notes 108, no. 1-2 (July 2020): 297–301. http://dx.doi.org/10.1134/s0001434620070329.

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28

Rao, P. S., T. J. Gillespie, and A. W. Schaafsma. "Estimating wetness duration on maize ears from meteorological observations." Canadian Journal of Soil Science 78, no. 1 (February 1, 1998): 149–54. http://dx.doi.org/10.4141/s97-012.

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The onset and cessation of surface wetness on maize ears were simulated with six models, using hourly meteorological data, to examine the linkage between wetness duration and possible forecasting of fungal infections that produce mycotoxins. Two threshold models (using relative humidity and dew point temperature), one regression model (using humidity and wind speed), and three physical models based on the energy balance approach, were compared. Also, spatial and temporal variability in wetness duration was measured and simulated at three sites located at distances up to 29 km from a central weather station. The estimated wetness values were compared with observations from cylindrical wetness sensors placed near ear level in maize canopies. The results relate to potential mycotoxin warning systems and indicate that threshold models can provide reasonable estimates of ear wetness duration in this region, that a comprehensive physical model can give superior estimates, and that wetness estimates made from a central weather station data can be extended to nearby crop fields with a moderate degree of confidence. Key words: epidemiology, mycotoxins, surface wetness models

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29

Алексеев, Владимир Николаевич. "On the question of cylindrical waves in elastic media." Вестник Чувашского государственного педагогического университета им. И.Я. Яковлева. Серия: Механика предельного состояния, no. 1(43) (March 27, 2020): 73–77. http://dx.doi.org/10.37972/chgpu.2020.43.1.008.

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Рассматривается задача о распространении цилиндрической волны сжатия в упругой среде. Получены значения радиальных смещений точек среды и радиальных напряжений. Указаны асимптотические оценки полученных решений для поля смещений в среде на больших расстояниях от источников волны, а также статистическое распределение смещений среды. The problem of propagation of a cylindrical compression wave in an elastic medium is considered. The values of radial displacements of medium points and radial stresses are obtained. Asymptotic estimates of the obtained solutions for the displacement field in the medium at large distances from the wave sources are given, as well as the statistical distribution of the displacement of the medium.

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30

Kuznetsov, N. V., M. Y. Lobachev, M. V. Yuldashev, and R. V. Yuldashev. "On the Gardner Problem for the Phase-Locked Loops." Доклады Академии наук 489, no. 6 (December 23, 2019): 541–44. http://dx.doi.org/10.31857/s0869-56524896541-544.

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This report shows the possibilities of solving the Gardner problem of determining the lock-in range for multidimensional phase-locked loops systems. The development of analogs of classical stability criteria for the cylindrical phase space made it possible to obtain analytical estimates of the lock-in range for third-order system.

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31

Brown, Simon, Kevin C. Pedley, and David C. Simcock. "Estimation of Surface Area and Volume of a Nematode from Morphometric Data." Scientifica 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/6767538.

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Nematode volume and surface area are usually based on the inappropriate assumption that the animal is cylindrical. While nematodes are approximately circular in cross section, the radius varies longitudinally. We use standard morphometric data to obtain improved estimates of volume and surface area based on (i) a geometrical approach and (ii) a Bézier representation of the nematode. These new estimators require only the morphometric data available from Cobb’s ratios, but if fewer coordinates are available the geometric approach reduces to the standard estimates. Consequently, these new estimators are better than the standard alternatives.

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32

Ancellin, Matthieu, Marlène Dong, Philippe Jean, and Frédéric Dias. "Far-Field Maximal Power Absorption of a Bulging Cylindrical Wave Energy Converter." Energies 13, no. 20 (October 20, 2020): 5499. http://dx.doi.org/10.3390/en13205499.

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The maximal power that is absorbed by a wave energy converter can be estimated from the far-field behavior of the waves that are radiated by the device. For realistic estimates, constraints must be used to enforce restrictions on the set of admissible motions when deriving the maximal absorption width. This work is dedicated to the numerical computation of the maximal absorption width under constraints for devices with several non-trivial degrees of freedom. In particular, the method is applied to a model of SBM Offshore’s S3 wave energy converter, a bulging horizontal cylinder. The results are compared with a more classical approach, which consists of computing the linear dynamic response of the wave energy converter interacting with the waves. The far-field maximal absorption width can be seen as an upper bound to evaluate what would be the power captured by a perfect control strategy. The method also shows that the absorption width of the S3 wave energy converter is larger for wavelengths that are smaller than the device length. In practice, this means that S3 wave energy converters will be longer than the maximal wavelength to be captured on the targeted production site.

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33

Sinha, Ramola, Nitin Gulhane, Jan Taler, and Pawel Oclon. "Heat loss analysis of three coil cylindrical solar cavity receiver of parabolic dish for process heat." Thermal Science 23, Suppl. 4 (2019): 1301–10. http://dx.doi.org/10.2298/tsci19s4301s.

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The share of solar thermal energy for process heat at sub cooled temperature is estimated about 30% of the total demand. The assessment of heat loss from tubular receiver used for the process heat is necessary to improve the thermal efficiency and consequently the cost effectiveness of the parabolic dish receiver system. The study considers a modified three coil solar cavity receiver of wall area three times (approximately) as compared to the existing single coil receiver and experimentally investigates the effect of increases in cavity inner wall area, fluid inlet temperature (50-75?C), and cavity inclination angle (? = 0-90?) on the combined (total) heat loss from receiver under no wind condition. This paper also develops an analytical model to estimate the different mode of heat losses from the downward facing receiver. In the mean fluid temperature range of 50?C to 70?C, the total heat loss from three coil receiver is reduced up to 40.98% at 90? and 20% at 0? inclination, as compared to single coil receiver. The analytical modeling estimates very low heat loss from conduction (1-3%) and radiation (2-8%) and high heat loss from convection (97-89%). The heat loss by natural convection decreases sharply with increase in cavity inclination, while the heat loss by radiation and conduction increases slowly with inclination. A three coil cavity receiver might be considered in the design to reduce heat loss from parabolic dish receiver system to improve the thermal performance and cost effectiveness.

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34

Paraev, S. A., and G. A. Kardashev. "Integrated approach to the technical condition of the process equipment." Izvestiya MGTU MAMI 8, no. 4-3 (June 20, 2014): 5–10. http://dx.doi.org/10.17816/2074-0530-67459.

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An integrated approach, based on the account of the probabilistic properties of a technical condition of the process equipment for example, evaluate the technical condition of cylindrical hydrocyclone with the use of either Bayesian. Provides diagnostic symptoms and associated diagnoses state. Discuss the results of estimates of the probabilities of the states, depending on the combination of selected features.

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35

Likhanov, I. I. "Modeling method for obtaining kinetic parameters of metamorphic reactions in texture-homogeneous rocks." Доклады Академии наук 488, no. 4 (October 10, 2019): 420–24. http://dx.doi.org/10.31857/s0869-56524884420-424.

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A new approach for deriving kinetic parameters of diffusion-controlled metamorphic reactions is described. It is based on comparison of models of temperature field evolution near a cylindrical intrusion and observable chemical changes in minerals at the contact aureole of the Kharlovo massif. The calculations yielded estimates of the effective rates of metamorphic reactions (~10-12 s-1) and the effective diffusion coefficient (5.29 10-16 cm2s-1 at T = 475 С). These values are consistent with experimentally and theoretically derived estimates of solid-state diffusion, including grain-boundary diffusion in mineral aggregates and segregations for the respective PT-parameters.

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36

V. Ivanov, Andrey. "Calculation of the Limiting Perveance of a Round Beam Partially Filling a Cylindrical Vacuum Chamber." Siberian Journal of Physics 6, no. 2 (July 1, 2011): 43–49. http://dx.doi.org/10.54362/1818-7919-2011-6-2-43-49.

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One of the effects of space charge is the charged particles current limitation in electron-optical systems. As a rule, for each specific system the limiting value of current can only be found on the results of numerical calculation, but the analytical treatment is necessary both for initial estimates of the parameters of the system and for understanding the physical basis of processes occurring in it. In this paper we consider a uniform circular beam of charged particles, partially filling a cylindrical vacuum chamber. The maximum perveance of this system depending on the ratio of pipe radius to beam radius is found, the comparison of this dependence with the results of numerical calculation of the system is carried out, as well as with the approximate analytical estimates

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37

Brunesi, Emanuele, and Roberto Nascimbene. "Effects of structural openings on the buckling strength of cylindrical shells." Advances in Structural Engineering 21, no. 16 (March 15, 2018): 2466–82. http://dx.doi.org/10.1177/1369433218764625.

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Computational models, which follow numerical assessment strategies codified by current European rules for shell buckling, were developed so as to study the buckling and post-buckling response of a large set of cylindrical steel thin-shell prototypes with structural openings. Behavioural changes as a consequence of variations in the cutout configuration, that is, shape, size, location and number, were predicted and the obtained numerical estimates were related to the test data of previous experiments in order to explore critical design aspects. Damage modes and axial force–axial displacement response curves were presented and discussed, decoupling the roles played by material nonlinearity and geometrical nonlinearity, as well as the contribution of initial geometrical imperfections to the buckling mechanism of axially compressed cylindrical thin shells.

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38

Ryoo, Ju-Mee, Laura T. Iraci, Tomoaki Tanaka, Josette E. Marrero, Emma L. Yates, Inez Fung, Anna M. Michalak, et al. "Quantification of CO<sub>2</sub> and CH<sub>4</sub> emissions over Sacramento, California, based on divergence theorem using aircraft measurements." Atmospheric Measurement Techniques 12, no. 5 (May 29, 2019): 2949–66. http://dx.doi.org/10.5194/amt-12-2949-2019.

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Abstract. Emission estimates of carbon dioxide (CO2) and methane (CH4) and the meteorological factors affecting them are investigated over Sacramento, California, using an aircraft equipped with a cavity ring-down greenhouse gas sensor as part of the Alpha Jet Atmospheric eXperiment (AJAX) project. To better constrain the emission fluxes, we designed flights in a cylindrical pattern and computed the emission fluxes from two flights using a kriging method and Gauss's divergence theorem. Differences in wind treatment and assumptions about background concentrations affect the emission estimates by a factor of 1.5 to 7. The uncertainty is also impacted by meteorological conditions and distance from the emission sources. The vertical layer averaging affects the flux estimate, but the choice of raw wind or mass-balanced wind is more important than the thickness of the vertical averaging for mass-balanced wind for both urban and local scales. The importance of vertical mass transfer for flux estimates is examined, and the difference in the total emission estimate with and without vertical mass transfer is found to be small, especially at the local scale. The total flux estimates accounting for the entire circumference are larger than those based solely on measurements made in the downwind region. This indicates that a closed-shape flight profile can better contain total emissions relative to a one-sided curtain flight because most cities have more than one point source and wind direction can change with time and altitude. To reduce the uncertainty of the emission estimate, it is important that the sampling strategy account not only for known source locations but also possible unidentified sources around the city. Our results highlight that aircraft-based measurements using a closed-shape flight pattern are an efficient and useful strategy for identifying emission sources and estimating local- and city-scale greenhouse gas emission fluxes.

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39

Awad, Emad S. "A Note on the Spatial Decay Estimates in Non-Classical Linear Thermoelastic Semi-Cylindrical Bounded Domains." Journal of Thermal Stresses 34, no. 2 (January 13, 2011): 147–60. http://dx.doi.org/10.1080/01495739.2010.511942.

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40

Tabone, C. J., and R. H. Mallett. "Pressure-Plus-Moment Limit-Load Analysis for a Cylindrical Shell Nozzle." Journal of Pressure Vessel Technology 109, no. 3 (August 1, 1987): 297–301. http://dx.doi.org/10.1115/1.3264867.

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A finite element model of a nozzle in a cylindrical shell is analyzed for three cases; pressure, out-of-plane moment and combined pressure plus out-of-plane moment. The model uses three-dimensional finite elements and the analysis considers inelastic behavior at small displacements. Load versus displacement behavior is given for the three cases. Estimates of limit loads are obtained based upon extrapolation of load versus inverse displacement data curves. An interaction expression is used to show the effect of the combined loading for a case in which an internal pressure reduces the moment capability of the nozzle by 35 percent.

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41

Kondo, Shintaro. "An almost-periodic solution of Hasegawa–Wakatani equations with vanishing resistivity." Proceedings of the Royal Society of Edinburgh: Section A Mathematics 146, no. 5 (June 23, 2016): 983–1003. http://dx.doi.org/10.1017/s0308210515000803.

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We consider the zero-resistivity limit for Hasegawa–Wakatani equations in a cylindrical domain when the initial data are Stepanov almost-periodic in the axial direction. First, we prove the existence of a solution to Hasegawa–Wakatani equations with zero resistivity; second, we obtain uniform a priori estimates with respect to resistivity. Such estimates can be obtained in the same way as for our previous results; therefore, the most important contribution of this paper is the proof of the existence of a local-in-time solution to Hasegawa–Wakatani equations with zero resistivity. We apply the theory of Bohr–Fourier series of Stepanov almost-periodic functions to such a proof.

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42

Lizama, Carlos, and Marina Murillo-Arcila. "Lp-Lq-Well Posedness for the Moore–Gibson–Thompson Equation with Two Temperatures on Cylindrical Domains." Mathematics 8, no. 10 (October 12, 2020): 1748. http://dx.doi.org/10.3390/math8101748.

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We examine the Cauchy problem for a model of linear acoustics, called the Moore–Gibson–Thompson equation, describing a sound propagation in thermo-viscous elastic media with two temperatures on cylindrical domains. For an adequate combination of the parameters of the model we prove Lp-Lq-well-posedness, and we provide maximal regularity estimates which are optimal thanks to the theory of operator-valued Fourier multipliers.

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43

Magan, Avnish Bhowan, David Mason, and Charis Harley. "Elastic waves in a circular cylinder and cylindrical annulus for a subclass of implicit constitutive equations." Mathematics and Mechanics of Solids 25, no. 2 (August 30, 2019): 201–33. http://dx.doi.org/10.1177/1081286519872233.

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The propagation of elastic waves in a circular cylinder and cylindrical annulus for two types of power-law constitutive equations is investigated. These power-law constitutive equations can describe elastic responses where the linearised strain and stress are nonlinearly related. These constitutive equations are a subclass of the more general class of implicit constitutive equations and are characterised by expressing the strain as a non-invertible function of the stress. Pseudo-solitary stress wave solutions for both types of constitutive equations in the circular cylinder and cylindrical annulus are derived. We find that for the power-law constitutive equation of Type I, a shock front will develop at the back of the wave while for the power-law constitutive equation of Type II, a shock front will develop at the front of the wave. Estimates of the times at which the shock front will develop are given. Standing wave solutions for both types of constitutive equations in the circular cylinder and cylindrical annulus are also obtained and the periods of oscillation are compared.

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OH, YONG-GEUN, and RUI WANG. "ANALYSIS OF CONTACT CAUCHY–RIEMANN MAPS II: CANONICAL NEIGHBORHOODS AND EXPONENTIAL CONVERGENCE FOR THE MORSE–BOTT CASE." Nagoya Mathematical Journal 231 (May 15, 2017): 128–223. http://dx.doi.org/10.1017/nmj.2017.17.

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This is a sequel to the papers Oh and Wang (Real and Complex Submanifolds, Springer Proceedings in Mathematics and Statistics 106 (2014), 43–63, eds. by Y.-J. Suh and et al. for ICM-2014 satellite conference, Daejeon, Korea, August 2014; arXiv:1212.4817; Analysis of contact Cauchy–Riemann maps I: a priori$C^{k}$estimates and asymptotic convergence, submitted, preprint, 2012, arXiv:1212.5186v3). In Oh and Wang (Real and Complex Submanifolds, Springer Proceedings in Mathematics and Statistics 106 (2014), 43–63, eds. by Y.-J. Suh and et al. for ICM-2014 satellite conference, Daejeon, Korea, August 2014; arXiv:1212.4817), the authors introduced a canonical affine connection on $M$ associated to the contact triad $(M,\unicode[STIX]{x1D706},J)$. In Oh and Wang (Analysis of contact Cauchy–Riemann maps I: a priori$C^{k}$estimates and asymptotic convergence, submitted, preprint, 2012, arXiv:1212.5186v3), they used the connection to establish a priori$W^{k,p}$-coercive estimates for maps $w:\dot{\unicode[STIX]{x1D6F4}}\rightarrow M$ satisfying $\overline{\unicode[STIX]{x2202}}^{\unicode[STIX]{x1D70B}}w=0$, $d(w^{\ast }\unicode[STIX]{x1D706}\circ j)=0$without involving symplectization. We call such a pair $(w,j)$ a contact instanton. In this paper, we first prove a canonical neighborhood theorem of the locus $Q$ foliated by closed Reeb orbits of a Morse–Bott contact form. Then using a general framework of the three-interval method, we establish exponential decay estimates for contact instantons $(w,j)$ of the triad $(M,\unicode[STIX]{x1D706},J)$, with $\unicode[STIX]{x1D706}$ a Morse–Bott contact form and $J$ a CR-almost complex structure adapted to $Q$, under the condition that the asymptotic charge of $(w,j)$ at the associated puncture vanishes.We also apply the three-interval method to the symplectization case and provide an alternative approach via tensorial calculations to exponential decay estimates in the Morse–Bott case for the pseudoholomorphic curves on the symplectization of contact manifolds. This was previously established by Bourgeois (A Morse–Bott approach to contact homology, Ph.D. dissertation, Stanford University, 2002) (resp. by Bao (On J-holomorphic curves in almost complex manifolds with asymptotically cylindrical ends, Pacific J. Math. 278(2) (2015), 291–324)), by using special coordinates, for the cylindrical (resp. for the asymptotically cylindrical) ends. The exponential decay result for the Morse–Bott case is an essential ingredient in the setup of the moduli space of pseudoholomorphic curves which plays a central role in contact homology and symplectic field theory (SFT).

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Myland, Jan C., Keith B. Oldham, Jörg Schiewe, and Alicia L. Taylor. "Article." Canadian Journal of Chemistry 76, no. 11 (November 1, 1998): 1688–94. http://dx.doi.org/10.1139/v98-129.

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Three methods are discussed by which the internal geometry of a porous insulator may be investigated electrochemically. By adopting a simple model, the pore geometry is characterized by two parameters: the tortuosity and the porosity. In each method, a cylindrical sample of the porous medium is soaked with an aqueous electrolyte solution and its lower face is brought into contact with a mercury pool electrode. The other electrode is also a mercury pool, but in the first technique it is remote, whereas in the second and third methods it floods the upper surface of the cylindrical sample. The first technique employs a d.c. potential step, whereby the concentration of a probe ion is depleted at the lower electrode. The attempt of diffusion to replenish this surface concentration leads to a faradaic current whose time dependence is analyzed to provide estimates of the tortuosity and porosity parameters. The second method measures the frequency-dependent cell impedance. The pore structure parameters are estimated from the equivalent circuit of the cell. No faradaic process is involved in the third method, which measures the frequency-dependent conductance of the cell as a means of characterizing the pore structure. These methods are applied successfully to sandstone and fritted glass samples.Key words: porous media, Fourier-transform methods, impedance.

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46

Chen, Huan, Feng Xu, and Shuai Su. "The Research of Cylindrical Noise Source Distribution Using Near-Field High-Resolution Location Methods Based on MVDR Algorithm." Applied Mechanics and Materials 226-228 (November 2012): 487–92. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.487.

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According to the lack of cylinder-model noise source localization technology based on near-field focused beam-forming, the paper aimed to find a near-field high-resolution method of the cylindrical noise source which is applied to measure the model as cylinder-models. This method established a near-field measurement model of noise sources using cylindrical measurement surface, and applied MVDR algorithm to noise sources localization. Reconstruct the cylinder measurement surface through the joint amplitude-phase compensation to achieve the noise source high-resolution localization and relative intensity estimates in the near-field. Verify the availability of this method through the simulations, which provided a theoretical basis for the next practical engineering application of the cylinder-model noise source localization based on near-field focused beam-forming.

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47

Batygin, Yu, T. Gavrilova, S. Shinderuk, and Yu Shcherbinina. "ELECTROMAGNETIC FIELDS IN A CYLINDRICAL INDUCTOR SYSTEM WITH AN EXTERNAL COAXIAL BIFILARY SOLENOID." Electromechanical and energy saving systems 1, no. 53 (March 25, 2021): 28–34. http://dx.doi.org/10.30929/2072-2052.2021.1.53.28-34.

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Purpose. Bifilar structures are widely used in modern electrical devices for various purposes. The specific interest is the using of inductor systems with external bifilar coils in the elements of modern metalworking equipment. In particular, it is very important to study the possibility of using such devices as elements of equipment for magnetic-pulse processing of metals. The aim of this research is a derivation of design expressions for theoretical analysis and numerical estimates of the characteristics of electromagnetic processes in a cylindrical inductor system. The case when the inductor is located inside a coaxial solenoid, the winding of which is made in the form of a bifilar with oppositely directed currents is considered. Methodology. Maxwell’s equations with appropriate boundary conditions and Laplace transforms are used to solve this problem. This made it possible to determine the expression for the z-th component of the magnetic field intensity excited in the considered inductor system. Results. It was found that the excited magnetic fluxes are subtracted outside the bifilar coil windings, which leads to a decrease in the resulting field compared to the magnetic field of each of the currents separately. Thus, it is possible to reduce the inductance of the coil as an element of the electrical circuit. It is shown that the formulas obtained for the fields and currents remain valid for the case of unidirectional currents when the sign of the corresponding algebraic term changes. Numerical estimates for the experimental model of the inductor system showed that the induced current as a percentage of the value of the exciting current does not exceed ~ 6.3 %. Originality. The novelty of this work lies in proposing the idea of constructive execution of the inductor system itself, as well as in considering its physical and mathematical model and obtaining calculated expressions for analyzing the ongoing electromagnetic processes with numerical estimates of the characteristics of the excited fields. Practical value. The obtained time dependences for voltages and currents induced in the bifilar winding are applicable depending on the design conditions for various specific designs of the inductor system

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48

Valls, Claudia. "Stability of some solutions for elliptic equations on a cylindrical domain." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 465, no. 2109 (June 10, 2009): 2647–62. http://dx.doi.org/10.1098/rspa.2009.0110.

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We study analytically a class of solutions for the elliptic equation where α >0 and ε is a small parameter. This equation is ill-posed and most initial conditions do not lead to solutions. Nevertheless, we show that, for almost every α >0, it contains solutions that are defined for large values of time and they are very close (of order O ( ε )) to a linear torus for long times (of order O ( ε −1 )). The proof uses the fact that the equation leaves invariant a smooth centre manifold and, for the restriction of the system to the centre manifold, uses arguments of classical perturbation theory by considering the Hamiltonian formulation of the problem, the Birkhoff normal form and Neckhoroshev-type estimates.

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49

Bachant, Peter, and Martin Wosnik. "Performance measurements of cylindrical- and spherical-helical cross-flow marine hydrokinetic turbines, with estimates of exergy efficiency." Renewable Energy 74 (February 2015): 318–25. http://dx.doi.org/10.1016/j.renene.2014.07.049.

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Storozhev, S. V., V. I. Storozhev, V. E. Bolnokin, Duong Minh Hai, and D. I. Mutin. "Fuzzy estimates of resonance frequencies for three-layer composite cylindrical panels in smart aerospace and industrial structures." Journal of Physics: Conference Series 1399 (December 2019): 044028. http://dx.doi.org/10.1088/1742-6596/1399/4/044028.

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