A radial variable for de Sitter two-point functions by Manuel Loparco, Jiaxin Qiao, Zimo Sun

“…We show that the two-point function of a free massive scalar in the Bunch-Davies vacuum has an exponentially convergent series expansion in this variable with positive coefficients only. …”
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Solitons, Lumps, Breathers, and Interaction Phenomena for a (2+1)-Dimensional Variable-Coefficient Extended Shallow-Water Wave Equation by Tianwei Qiu, Zhen Wang, Xiangyu Yang, Guangmei Wei, Fangsen Cui

“…In this paper, soliton solutions, lump solutions, breather solutions, and lump-solitary wave solutions of a (2+1)-dimensional variable-coefficient extended shallow-water wave (vc-eSWW) equation are obtained based on its bilinear form. …”
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Significance of dissipative flow on a second-grade nanofluid with variable thermal properties on the stretching surface by Zia Ullah, Aamir Abbas Khan, Shalan Alkarni, Abhinav Kumar, N. Beemkumar, Tushar Aggarwal, Ashwin Jacob, Jajneswar Nanda, Feyisa Edosa Merga

“…Boundary conditions are used for the analysis of heat and mass transmission. Stream functions and similarity variables are utilized to reduce the complexity of the governed PDEs (partial differential equations) and altered into ODEs (ordinary differential equations). …”
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An Ultrafast Image Simulation Technique with Spatially Variable Point-spread Functions by Zeyu Bai, Peng Jia, Jiameng Lv, Xiang Zhang, Wennan Xiang, Lin Nie

“…During real observations, images obtained by optical telescopes are affected by spatially variable point-spread functions (PSFs), a crucial effect requiring accurate simulation. …”
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Analysis of the Influence of Clutch Drag Torque on the Efficiency of Hydro-mechanical Continuously Variable Transmission by Rong Chai, Mingzhu Zhang, Jianhua Wang, Fang Jia

“…In order to study the influence of multiple clutches on the transmission efficiency of a hydro-mechanical continuously variable transmission （HMCVT），the structure characteristics of a closed loop consisting of multiple wet friction clutches in the transmission are investigated. …”
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Analysis of Meshing Efficiency of Straigh Bevel Gear based on Integrated Lubrication by Tang Xiaogui, Wang Bin, Li Peihong, Chen Xinbo

“…In order to predict the transient meshing efficiency of bevel gear pairs,a theoretical model of friction coefficient is established under boundary lubrication,elastohydrodynamic lubrication and mixed lubrication based on the principle of equivalent gear theory,by simplifying bevel gear into equivalent straigh gear,and by computing oil film-thickness ratio. …”
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Enhancing joint efficiency in friction stir welding of PA66 using an induction-heated threaded pin and glass fiber reinforcement by Ammar Elsheikh, Mohamed Ahmed Elmosalamy, Ninshu Ma, Ibrahim Eldeeb, Ezzat Showaib, Saad Ebied

“…This study investigates the friction stir welding (FSW) of polyamide 66 (PA66) sheets using an induction-heated threaded pin tool with a stationary shoulder. …”
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Arbitrary Random Variables and Wiman’s Inequality by Andriy Kuryliak, Oleh Skaskiv, Andriy Bandura

“…We study the class of random entire functions given by power series, in which the coefficients are formed as the product of an arbitrary sequence of complex numbers and two sequences of random variables. …”
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The Gini coefficient and discontinuity by Jens Peter Kristensen

“…This article reveals a discontinuity in the mapping from a Lorenz curve to the associated cumulative distribution function. The problem is of a mathematical nature—based on an analysis of the transformation between the distribution function of a bound random variable and its Lorenz curve. …”
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The analysis of the "Theory of functions of the complex variable" test with attraction of models Russia and Birnbaum by Lidia A. Muratova

“…In work the analysis of the "Theory of Functions of a Complex Variable" test is carried out. …”
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EVALUATION OF SUBSOIL MASSIF STABILITY TAKING INTO ACCOUNT THE IRREGULARITY OF CONSTITUENT ROCKS ON THE BASIS OF A RANDOM SIZE AND FUNCTION MODEL by M. O. Allaev

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An Analytical Approximation of the Stress Function for Conical Flywheels by Miguel Garcia, Onofre Orozco-López, Jesús Uribe-Chavira, Andrés Blanco-Ortega

“…Starting from a stress function, the model was simplified under the assumption of a small-thickness gradient, allowing the derivation of a closed-form solution. …”
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Investigating fluctuation varieties in the propagation of the perturbed KdV equation with time-dependent perturbation coefficient by Marwan Alquran

“…By assigning various functional forms such as periodic, polynomial, and decaying exponential, to the proposed time-dependent coefficient, novel solitary wave patterns of types like-breather, regular(singular)-bell shaped, and periodic solutions are emerged with fluctuations. …”
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Efficient and variable viscosity fracturing fluid of deep coal rock gas and popularization in ultimate volume fracturing by Bo LIN, Shuai CHEN, Xiangyang YAN, Mengqi CHEN, Liangjun DU, Heng CHEN, Hongsheng LU, Shuai SUN

“…By taking the advantage of SFY-2, a efficient and variable viscosity fracturing fluid is constructed to fit the design idea of coal rock gas Ultimate volume Fracturing, the variable viscosity control scheme is formulated and the construction technology is optimizated to achieve the goal of “Breaking” the coal rock sufficiently, creating complex sewing nets, filling sands fully and supporting effective. …”
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Variability of Interpolation Errors and Mutual Enhancement of Different Interpolation Methods by Yunxia He, Mingliang Luo, Hui Yang, Leichao Bai, Zhongsheng Chen

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Modeling creep for a closed cylindrical shell under hydrostatic pressure by M. A. Magomedov, V. V. Kuznetsov, B. M. Yazyev, S. V. Litvinov

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An Improvement of Least Squares Theory: Theory of Least p-Variances Approximation and p-Uncorrelated Functions by Mohammad Masjed-Jamei

“…In this direction, some new concepts, such as p-covariances with respect to a fixed variable, p-correlation coefficients with respect to a fixed variable, and p-uncorrelatedness with respect to a fixed variable, are defined in order to establish least p-variance approximations. …”
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Application of the Complex Variable Function Method to SH-Wave Scattering Around a Circular Nanoinclusion by Hongmei Wu

“…This paper focuses on analyzing SH-wave scattering around a circular nanoinclusion using the complex variable function method. The surface elasticity theory is employed in the analysis to account for the interface effect at the nanoscale. …”
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Predicting filtration coefficient and formation damage coefficient for particle flow in porous media using machine learning by Xuejia Du, George K. Wong

“…The clogging of porous media with solid particle suspension flow is modeled using two empirical parameters of filtration coefficient (λ) and formation damage coefficient (β). …”
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A Case Study on the Influence of Friction Coefficient and Rotational Speed on Transient Thermoelastic Response of FGM Rotating Cylinder by Reza Koohi Faegh Dehkourdi, Mostafa Omidi Bidgoli, Mohammad Hosseini

“…The material property is assumed to be variable along radius according to a volume fraction distribution. …”
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