Relevant bibliographies by topics / Nonlinearities of the concave-convex type

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  1. Journal articles
  2. Dissertations / Theses
  3. Book chapters
  4. Conference papers

Academic literature on the topic 'Nonlinearities of the concave-convex type'

Author: Grafiati
Published: 4 June 2021
Last updated: 14 February 2022

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Journal articles on the topic "Nonlinearities of the concave-convex type"

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Zhang, Haiyan, Yaohong Li, and Jiafa Xu. "Positive Solutions for a System of Fractional Integral Boundary Value Problems Involving Hadamard-Type Fractional Derivatives." Complexity 2019 (October 13, 2019): 1–11. http://dx.doi.org/10.1155/2019/2671539.

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In this paper, we use fixed-point index to study the existence of positive solutions for a system of Hadamard fractional integral boundary value problems involving nonnegative nonlinearities. By virtue of integral-type Jensen inequalities, some appropriate concave and convex functions are used to depict the coupling behaviors for our nonlinearities fii=1, 2.
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Hsu, Tsing-San. "On the Elliptic Problems Involving Multisingular Inverse Square Potentials and Concave-Convex Nonlinearities." Abstract and Applied Analysis 2011 (2011): 1–22. http://dx.doi.org/10.1155/2011/408307.

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A semilinear elliptic problem with concave-convex nonlinearities and multiple Hardy-type terms is considered. By means of a variational method, we establish the existence and multiplicity of positive solutions for problem .
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Liao, Jia-Feng, Yang Pu, Xiao-Feng Ke, and Chun-Lei Tang. "Multiple positive solutions for Kirchhoff type problems involving concave-convex nonlinearities." Communications on Pure & Applied Analysis 16, no. 6 (2017): 2157–75. http://dx.doi.org/10.3934/cpaa.2017107.

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Carboni, Giulia, and Dimitri Mugnai. "On some fractional equations with convex–concave and logistic-type nonlinearities." Journal of Differential Equations 262, no. 3 (2017): 2393–413. http://dx.doi.org/10.1016/j.jde.2016.10.045.

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Bueno, H. P., E. Huerto Caqui, O. H. Miyagaki та F. R. Pereira. "Critical Concave Convex Ambrosetti–Prodi Type Problems for Fractional 𝑝-Laplacian". Advanced Nonlinear Studies 20, № 4 (2020): 847–65. http://dx.doi.org/10.1515/ans-2020-2106.

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AbstractIn this paper, we consider a class of critical concave convex Ambrosetti–Prodi type problems involving the fractional 𝑝-Laplacian operator. By applying the linking theorem and the mountain pass theorem as well, the interaction of the nonlinearities with the first eigenvalue of the fractional 𝑝-Laplacian will be used to prove existence of multiple solutions.
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El Hamidi, Abdallah. "Multiple solutions to a nonlinear elliptic equation involving Paneitz type operators." International Journal of Mathematics and Mathematical Sciences 2004, no. 46 (2004): 2453–72. http://dx.doi.org/10.1155/s0161171204305119.

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This paper deals with an elliptic equation involving Paneitz type operators on compact Riemannian manifolds with concave-convex nonlinearities and a real parameter. Nonlocal and multiple existence results are established. Characteristic values of the real parameter are introduced and their role in the change of the energy sign and the existence of positive solutions are highlighted.
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Kaufmann, Uriel, Humberto Ramos Quoirin, and Kenichiro Umezu. "Loop Type Subcontinua of Positive Solutions for Indefinite Concave-Convex Problems." Advanced Nonlinear Studies 19, no. 2 (2019): 391–412. http://dx.doi.org/10.1515/ans-2018-2027.

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AbstractWe establish the existence of loop type subcontinua of nonnegative solutions for a class of concave-convex type elliptic equations with indefinite weights, under Dirichlet and Neumann boundary conditions. Our approach depends on local and global bifurcation analysis from the zero solution in a nonregular setting, since the nonlinearities considered are not differentiable at zero, so that the standard bifurcation theory does not apply. To overcome this difficulty, we combine a regularization scheme with a priori bounds, and Whyburn’s topological method. Furthermore, via a continuity argument we prove a positivity property for subcontinua of nonnegative solutions. These results are based on a positivity theorem for the associated concave problem proved by us, and extend previous results established in the powerlike case.
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Iaia, Joseph A., and Sudhasree Gadam. "Exact multiplicity of positive solutions in semipositone problems with concave-convex type nonlinearities." Electronic Journal of Qualitative Theory of Differential Equations, no. 4 (2001): 1–9. http://dx.doi.org/10.14232/ejqtde.2001.1.4.

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Zheng, Qin, and Dong-Lun Wu. "Multiple Solutions for Schrödinger Equations Involving Concave-Convex Nonlinearities Without (AR)-Type Condition." Bulletin of the Malaysian Mathematical Sciences Society 44, no. 5 (2021): 2943–56. http://dx.doi.org/10.1007/s40840-021-01096-w.

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Luo, Xiaorong, Anmin Mao, and Xiangxiang Wang. "Multiplicity of Quasilinear Schrödinger Equation." Journal of Function Spaces 2020 (May 11, 2020): 1–5. http://dx.doi.org/10.1155/2020/1894861.

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In this paper, we study the quasilinear Schrödinger equation involving concave and convex nonlinearities. When the pair of parameters belongs to a certain subset of ℝ2, we establish the existence of a nontrivial mountain pass-type solution and infinitely many negative energy solutions by using some new techniques and dual fountain theorem. Recent results from the literature are improved and extended.
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Dissertations / Theses on the topic "Nonlinearities of the concave-convex type"

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Cavalcante, Thiago Rodrigues. "Multiplicidade de soluções para uma classe de problemas elípticos de quarta ordem com condição de contorno de Navier." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8257.

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Submitted by Erika Demachki (erikademachki@gmail.com) on 2018-03-23T22:13:05Z No. of bitstreams: 2 Tese - Thiago Rodrigues Cavalcante - 2018.pdf: 2200622 bytes, checksum: 39118adda6b7ceff14825da442b5be57 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)<br>Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-03-26T12:16:44Z (GMT) No. of bitstreams: 2 Tese - Thiago Rodrigues Cavalcante - 2018.pdf: 2200622 bytes, checksum: 39118adda6b7ceff14825da442b5be57 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)<br>Made available in DSpace on 2018-03-26T12:16:44Z (GMT). No. of bitstreams: 2 Tese - Thiago Rodrigues Cavalcante - 2018.pdf: 2200622 bytes, checksum: 39118adda6b7ceff14825da442b5be57 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-27<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>In the first two chapters, we consider the following problem \begin{equation*} \left \{ \begin{array}{rcll} \alpha \Delta^{2} u + \beta \Delta u & = & f(x,u)\, & \mbox{in}\,\, \Omega \\ u = \Delta u & = & 0 \, &\mbox{on } \,\,\, \partial \Omega, \end{array} \right. \end{equation*} where $\displaystyle{\Delta^{2} u = \Delta(\Delta u)-\,\mbox{biharmonic (fourth-order operator)}}$, $\alpha > 0$ and $ \beta \in \R.$ The subset $\displaystyle{ \Omega \subset \mathbb{R}^{N}\, (N \geq 4)}$ is as somooth bounded domain and $\displaystyle{ f \in C(\overline{\Omega} \times \mathbb{R},\mathbb{R}) }.$ In each of the results obtained, we will consider different technical hypotheses and characteristics for the nonlinear function $f$ e for the value of the constant $ \beta. $ In the third chapter, we study an equation of the concave type super linear, of the form: \begin{equation} \left \{ \begin{array}{rcll} \alpha \Delta^{2} u + \beta \Delta u & = & a(x)|u|^{s-2}u + f(x,u)\, & \mbox{in}\,\, \Omega \\ u = \Delta u & = & 0 \, &\mbox{on} \,\,\, \partial \Omega, \end{array} \right. \end{equation} where $\beta \in (-\infty, \alpha \lambda_{1}).$ We consider that the function $a \in L^{\infty} (\Omega)$ and $s \in (1,2).$ Finally, in the last chapter we will consider a fourth order problem in which nonlinearity is also of the convex concave type. More precisely, we study the following class of equations: \begin{equation} \left\{ \begin{aligned} \alpha \Delta^{2} u + \beta \Delta u & = \mu a(x)|u|^{q-2}u + b(x)|u|^{p-2}u&\,\,\,\,\ &\mbox{in}\,\, \Omega \\ u = \Delta u & = 0 & \,\,\,\,&\mbox{on} \,\, \partial \Omega, \end{aligned} \right. \end{equation} where the parameter $ \mu > 0 $, the powers $ 1 <q <2 <p <2 N / (N - 4) $. In addition we assume that the functions $ \displaystyle {a, b: \Omega \rightarrow \mathbb {R}}$ are continuous that can change signal and, $ a ^{+}, b ^{+} \neq 0. $<br>Nos dois primeiros Capítulos, consideramos a seguinte classe de problemas: \begin{equation*} \left \{ \begin{array}{rcll} \alpha \Delta^{2} u + \beta \Delta u & = & f(x,u)\, & \mbox{em}\,\, \Omega \\ u = \Delta u & = & 0 \, &\mbox{sobre } \,\,\, \partial \Omega, \end{array} \right. \end{equation*} onde $\displaystyle{\Delta^{2} u = \Delta(\Delta u)-\,\mbox{biharmônico},}$ $\alpha > 0$ e $ \beta \in \R.$ O subconjunto $\displaystyle{ \Omega \subset \mathbb{R}^{N}\,(N \geq 4)}$ será um domínio limitado e a não linearidade $\displaystyle{ f \in C(\overline{\Omega} \times \mathbb{R},\mathbb{R}) }.$ Em cada um dos resultados obtidos, consideraremos hipóteses técnicas e características diferentes para a função não linear $f$ e para o valor da constante $\beta.$ No terceiro Capítulo, estudamos uma equação do tipo côncavo super linear, da forma: \begin{equation*} \left \{ \begin{array}{rcll} \alpha \Delta^{2} u + \beta \Delta u & = & a(x)|u|^{s-2}u + f(x,u)\, & \mbox{em}\,\, \Omega \\ u = \Delta u & = & 0 \, &\mbox{sobre } \,\,\, \partial \Omega, \end{array} \right. \end{equation*} onde $\alpha > 0$ e $\beta \in (-\infty, \alpha \lambda_{1})$. Consideramos que a função $a \in L^{\infty}(\Omega)$ e que $s \in (1,2).$ Por fim, no último Capítulo vamos considerar um problema de quarta ordem no qual a não linearidade é do tipo côncavo-convexa. Mais precisamente, estudamos a seguinte classe de equações: \begin{equation*} \left\{ \begin{aligned} \alpha \Delta^{2} u + \beta \Delta u & = \mu a(x)|u|^{q-2}u + b(x)|u|^{p-2}u&\,\,\,\,\ &\mbox{em}\,\, \Omega \\ u = \Delta u & = 0 & \,\,\,\,&\mbox{sobre} \,\, \partial \Omega, \end{aligned} \right. \end{equation*} onde o parâmetro $\mu > 0$ e as potências $ 1 < q < 2 < p < 2 N /(N - 4)$. Adicionalmente supomos que as funções $\displaystyle{a, b : \Omega \rightarrow \mathbb{R} }$ sejam contínuas podendo trocar de sinal em $\Omega$ e que $a^{+},b^{+} \neq 0.$
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Sousa, Karla Carolina Vicente de. "Problemas elípticos semilineares com não linearidades do tipo côncavo-convexo." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/6897.

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Submitted by JÚLIO HEBER SILVA (julioheber@yahoo.com.br) on 2017-03-03T18:04:36Z No. of bitstreams: 2 Dissertação - Karla Carolina Vicente de Sousa 2017.pdf: 802534 bytes, checksum: b021fd17684c91eaed58191b3674afd7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)<br>Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-06T10:40:35Z (GMT) No. of bitstreams: 2 Dissertação - Karla Carolina Vicente de Sousa 2017.pdf: 802534 bytes, checksum: b021fd17684c91eaed58191b3674afd7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)<br>Made available in DSpace on 2017-03-06T10:40:35Z (GMT). No. of bitstreams: 2 Dissertação - Karla Carolina Vicente de Sousa 2017.pdf: 802534 bytes, checksum: b021fd17684c91eaed58191b3674afd7 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-03-01<br>Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq<br>In this work we study the existence of positive solutions for the following semilinear elliptic problem with concave-convex nonlinearities    −∆u = λa(x)u q +b(x)u p , x ∈ Ω u = 0, x ∈ ∂Ω where Ω is a bounded domain in R N with smooth boundary and 0 < q < 1 < p < 2 ∗−1 (where 2∗−1 = +∞, if N = 1 or N = 2 and 2∗−1 = N+2 N−2 , where N ≥ 3). Furthermore, λ > 0 is a parameter and a,b : Ω → R are continuous functions which are somewhere positives, however, such functions may change sign in Ω.<br>Neste trabalho estudaremos a existência de soluções positivas para o seguinte problema elíptico semilinear com não linearidades do tipo côncavo-conexo    −∆u = λa(x)u q +b(x)u p , x ∈ Ω u = 0, x ∈ ∂Ω onde Ω é uma domínio limitado de R N , com bordo regular e 0 < q < 1 < p < 2 ∗ −1 (onde 2∗ −1 = +∞, se N = 1 ou N = 2 e 2∗ −1 = N+2 N−2 , quando N ≥ 3). Além disso, λ > 0 é um parâmetro e a,b : Ω → R são funções contínuas que assumem valores positivos, porém, tais funções podem mudar de sinal em Ω.
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Silva, Rosinângela Cavalcanti da. "Existência de soluções para equações elípticas semilineares envolvendo não linearidades do tipo côncavo-convexas." Universidade Federal da Paraí­ba, 2012. http://tede.biblioteca.ufpb.br:8080/handle/tede/7374.

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Made available in DSpace on 2015-05-15T11:46:05Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 813665 bytes, checksum: 8aa09df2661d8ea4c0561ebad8cd9584 (MD5) Previous issue date: 2012-07-31<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>The goal of our work is to prove the existence of solutions to a class of semilinear elliptic equations in a bounded domain, involving concave-convex type nonlinearities. We use a variety of methods to and these solutions, such as Mountain Pass Theorem, Ekeland's Variational Principle, Lagrange Multipliers Theorem, Nehari Manifold and sub and supersolution method.<br>O objetivo da nossa dissertação é provar a existência de soluções para uma classe de equações elípticas semilineares em um domínio limitado, envolvendo não linearidades do tipo côncavo-convexas. Mostraremos alguns casos diferentes e métodos diversificados para encontrar tais soluções, usando o Teorema do Passo da Montanha, o Princípio Variacional de Ekeland, Teorema dos Multiplicadores de Lagrange, a Variedade de Nehari e sub e supersolução.
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HUANG, JING-JYUN, and 黃靜君. "A classification of bifurcation curves of a boundary value problem with convex-concave nonlinearities." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/x3s6g2.

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碩士<br>國立臺南大學<br>應用數學系碩士班<br>107<br>We study the bifurcation curves of positive solutions of boundary value problem {(u"(x)+f_λ (u(x))=0,-1<x<1,u(-1)=u(1)=0,)┤where f_λ (u)=λg(u)+h(u),g,hC^2 [0,∞) and λ>0 is a bifurcation parameter. We assume that functions g and h satisfy hypotheses (H1)-(H3). Under hypotheses (H1)-(H3), we give a classification of bifurcation curves, and we prove that, on the (λ,‖u‖_∞)-plane, each bifurcation curve consists of exactly one curve which is either a monotone curve or has exactly one turning point where the curve turns to the right. Hence the problem has at most two positive solutions for each λ>0.
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Yang, Yuan-Ju, and 楊媛茹. "Study on the Convex- and Concave-Type Parallax-Barrier Autostereoscopic Displays." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/61211650459918354219.

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碩士<br>國立臺灣大學<br>光電工程學研究所<br>104<br>Among the 3D imaging technology, the auto-stereoscopic 3D display technology has generally accepted because of its advantages about no need to wear glasses and various use. In recent years, the rise of flexible display make wearable displays and curved displays spring up, such as smart watch and curved smart phone and the research of the curved display is more important. Based on the bending direction, Curved displays are divided into concave-type displays and convex-type displays and provide the more natural and comfortable visual experience. The concave-type displays provide the effect of Panorama image and the convex-type provide the effect of Surrounding image. Therefore, the curved auto-stereoscopic display is highly expected in the future. For an auto-stereoscopic display, viewing position and the movable range for observers strongly affect image quality. Viewing zone describes the range that an observer could move while experiencing 3D images in front of the display. Regarding a curved auto-stereoscopic display, radius of curvature and width of the screen determine the relative degree of bending, by which the spacial light distribution is determined. In addition, this is a key factor influencing image quality, especially for the display which directs the views for left and right eyes based on binocular parallax. In this thesis, we investigate the effect of viewing zones with concave-type and convex-type in small size displays(such as mobile devices), medium size displays(such as desktop monitors) and large size displays(such as televisions) by modulating the radius of curvature. According to the results, both concave-type and convex-type can be applied for small size displays and medium size displays by different use, and the concave-type is better than convex-type for large size displays. Meanwhile, the limitation factors of the concave-type and convex-type are studied in this thesis. The purpose of this thesis is to provide a reference for designing the parameters of curved auto-stereoscopic displays in the future.
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Wang, Hung-Ta, and 王鴻達. "A note on integral inequalities of Hadamard type for log-convex and log-concave functions." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/y5mnn7.

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Book chapters on the topic "Nonlinearities of the concave-convex type"

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Benouhiba, Nawel, and Amina Bounouala. "Concave and convex nonlinearities in nonstandard eigenvalue problems." In Applied Mathematics in Tunisia. Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-18041-0_21.

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Benmansour, Safia, Atika Matallah, and Mustapha Meghnafi. "Multiple solutions for nonlocal elliptic problems with concave–convex nonlinearities and weights." In Operator Theory. De Gruyter, 2021. http://dx.doi.org/10.1515/9783110598193-016.

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Wang, Y., Z. Feng, KL Cheng, et al. "Role of differentially expressed LBX1 in Adolescent Idiopathic Scoliosis (AIS) paraspinal muscle phenotypes and muscle-bone crosstalk through modulating myoblasts." In Studies in Health Technology and Informatics. IOS Press, 2021. http://dx.doi.org/10.3233/shti210425.

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AIS is three-dimensional spinal deformity with unclear etiopathogenesis. LBX1 is so far the only multi-centers validated AIS predisposing gene. The imbalance of posterior paraspinal muscles is an important factor in AIS etiopathogenesis. It is poorly understood how LBX1 contributes to the abnormal paraspinal muscles and onset/progression of AIS. We aimed to evaluate the expression of LBX1 in paraspinal muscles at the concave and convex side in AIS, and whether alternation of LBX1 expression could affect myoblastsactivities and potentially influence muscle-bone interaction via myokines expression. Paraspinal muscles from AIS and age- and curvature-matched congenital scoliosis (CS) patients were collected for fiber types analysis. Biopsies were also subjected to qPCR to validate expression of myogenic markers, selected myokines and LBX1. Human skeletal muscle myoblast (HSMM) was used for LBX1 loss-of-function study in vitro. Muscle fiber types analysis showed type I and type IIX/IIAX fibers proportion were significantly different between AIS concave and convex but not in two sides of CS. LBX1, myogenic markers and one myokine were significantly imbalanced in AIS but not in CS. Loss-of-function study showed knockdown of LBX1 could inhibit myogenic markers expression and myokines as well. This study provides new insight into the association between imbalanced paraspinal muscle and potential muscle-bone crosstalk in AIS patients and the biological function of predisposing gene LBX1. Further investigation with appropriate animal models is warranted to explore if asymmetric expression of LBX1 could result in distinct muscle phenotypes and bone qualities thus affect the progression of spine curvature in AIS.
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Allison, Penelope M. "Casa degli Amanti Supplement." In The Insula of the Menander at Pompeii. Oxford University Press, 2007. http://dx.doi.org/10.1093/oso/9780199263127.003.0026.

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The following artefacts have been mounted for display on a board which in 2001 was hanging on the south wall of the peristyle garden of this house (Plate 125.1) i. Dimensions: 75 mm × 80 mm × 30 mm. Description: Iron lock case. In each corner is an iron attachment nail with sub-hemispherical head (diam.: c.13 mm). Traces of a keyhole. Present location: Casa degli Amanti, wooden board (middle row, right). ii. Dimensions: 85 mm × 77 mm × 25 mm. Description: Iron lock case with a flat-head, iron attachment nail (diam.: c.20 mm) in each corner. L-shaped keyhole (max. l.: 23 mm). Rectangular slit (c.3 mm × 25 mm) near one edge. Present location: Casa degli Amanti, wooden board (middle row, second right). Discussion: Both similar to cat. no. 1935. Possibly cat. nos. 1826 and 1859. See discussion on locks and keys. i. Dimensions: preserved l. of blade: c.170 mm; max. w.: c.75 mm; max. thickness: c.15 mm. Description: Curved axe blade with one side convex and the other concave. Poll badly corroded. Present location: Casa degli Amanti, wooden board (top row, left). ii. Dimensions: preserved l. of blade: c.190 mm; max. w.: c.75 mm; dimensions of poll: 55 mm × 40 mm. Description: Curved axe blade with one side convex and the other concave. Circular eye (diam.: c.30 mm) with the remains of a wooden handle. Present location: Casa degli Amanti, wooden board (top row, second from left). iii. Dimensions: preserved l. of blade: c.175 mm; max. w.: c.50 mm; poll: 55 mm × 40 mm. Description: Curved axe blade with one side convex and the other concave. Circular eye (diam.: c.30 mm). Poll badly damaged. Present location: Casa degli Amanti, wooden board (top row, third from left). Discussion: These axes are Manning type 4 (1985: 16). Possibly cat. nos. 1780 and 1781. See discussion on axes. i. Dimensions: total l.: c.210 mm; max. w. of blade: c.55 mm; max. thickness: 15 mm. Description: approximately right-angled blade. Present location: Casa degli Amanti, wooden board (second row, left). ii. Dimensions: total l.: c.215 mm; max. w. of blade: c.60 mm; max. thickness: 10 mm.
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"* ** Fig. 39 Cyclone-type homogenizer mixing chamber. (From Ref. 41.) chamber. The symmetry axes of these entry ports are perpendicular to the symmetry axis of the interaction chamber. This design is presented in Fig. 40, with only four entry ports. This machine is called Novamix® (a registered name for Micro Vesicular Sys-tems). It was originally designed to process and produce nonphospholipid lamellar mi-crostructures or lipid vesicles. The lipid vesicles are composed of two immiscible aqueous and lipid phases. The lipid phase consists, generally, of solid polyoxyethylene-derived amphiphiles that form micelles in aqueous media. Under the proper mixing conditions, i.e., a combination of shear, heat, and turbulence, followed by appropriate cooling, the micelles of these types of lipids fuse to form lipid vesicles. The two phases are metered carefully and heated in separate reservoirs and finally pumped to the interaction chamber for pro-cessing. The interaction chamber and pump heads are confined in an insulated com-partment that is maintained at the required temperature for the production of the lipid vesicles. The outlet is attached to a chilling device that cools the product at the required rate [43]. The flow pattern is similar to that of a cyclone, i.e., the flow of liquid is in a vertically positioned rotating cylinder along its vertical axis. The streamlines are con-centric circles with their radii decreasing toward the center of the cylinder. The de-crease is a function of cylinder radius, flow rate of fluid (speed of rotation), and other parameters like viscosity, density, and surface tension of the formulation. In curved type of flow with changing radii, there exists a pressure gradient, i.e. dPIdr = V /r (8) where P = pressure; r = vessel (interaction chamber) radius; V = tangential linear velocity; and p= the liquid density. Since the change in pressure is positive for a positive radius change, the pressure at successive points increases from the concave to the convex side of the streamline [39]. The exact change in pressure depends on the variation in tangential linear velocity, which is proportional to the speed of the rotation and the ra-dius. The flow pattern in the interaction chamber is neither a free vortex, due to the presence of an initial momentum from the pumps, nor a forced vortex, for the stream-." In Pharmaceutical Dosage Forms. CRC Press, 1998. http://dx.doi.org/10.1201/9781420000955-55.

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Conference papers on the topic "Nonlinearities of the concave-convex type"

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Almeter, John, and Will Newman. "Performance Improvements from a Concave/Convex Planning Surface - Wiggle Hull." In SNAME Maritime Convention. SNAME, 2014. http://dx.doi.org/10.5957/smc-2014-t18.

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Concave camber can increase lift and Lift to Drag of a planing hull. The impact of camber and its limitations for a planing hull are reviewed, including model tests. The adverse impacts of low trims and excessive camber are discussed. A practical planing hull with significant concave camber must have convexity, at least forward to accommodate the bow. This hull type is generically referred to as a Wiggle Hull and recent investigations to develop such a hull are presented. The prediction method developed for this investigation is described.
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Fu, Xing, Qiang Liu, and Mali Gong. "Variation of thermal lens curvature type between the convex and the concave lens for zigzag slab laser." In Photonics Asia, edited by Upendra N. Singh, Dianyuan Fan, Jianquan Yao, and Robert F. Walter. SPIE, 2012. http://dx.doi.org/10.1117/12.981709.

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Merat, Kaveh, Jafar Abbaszadeh Chekan, Hassan Salarieh, and Aria Alasty. "Online Hybrid Model Predictive Controller Design for Cruise Control of Automobiles." In ASME 2017 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/dscc2017-5274.

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In the proposed study, a Hybrid Model Predictive Controller is introduced for cruise control of an automobile model. The presented model consists of the engine, the gearbox, and the transmission dynamics, where the aerodynamics force and elastic friction between the tires and road are taken into account. Through Piecewise Linearization of nonlinearities in the system; (torque)-(throttle)-(angular velocity) of engine and (aerodynamic drag force)-(automobile velocity), a comprehensive piecewise linear model for the system is obtained. Then combined with the switch and shift between engaged gears in gearbox, the Piecewise Affine (PWA) model for the vehicle dynamics is acquired. As far as the control design is concerned, the cruise control problem for tracking a desired speed fashion is addressed by a MPC-based controller design. The proposed control approach is based on the online model predictive control, applied on the obtained PWA dynamics. The highlighted novelties of the presented research work are summarized as: first a more complete model is examined due to the consideration of a realistic model for engine. This improvement makes the polyhedron regions of the PWA system dependent to both state variable (i.e., velocity) and input signals (i.e., throttle and engaged gear) which brings the complexity to the design of control procedure. Second, due to the switch in the dynamics and dependence of our PWA model to discrete input (gear shift), the desperate need to solve the optimization problem through mixed integer programming, which needs high computation effort specially for our system, seems inevitable. We triumph over this challenge through introducing “possible gear shift scenario” sets. Hence, by constraining the optimization problem to the introduced logical sets, the problem still remains convex optimization type and the computation volume is reduced. In addition, we hired branch and bound method which allowed us to have large problems to be solved in a tractable amount of time and computation resources. At last, some simulations are presented to exhibit the performance of the proposed method.
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4

Gattas, Joseph M., and Yan Chen. "Synthesis of Folded Frame Structures From Cube-Type and Eggbox-Type Kirigami Geometry." In ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/detc2015-46433.

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Rigid-foldable cube-type and eggbox-type kirigami geometries have been of interest for applications including folded-core sandwich panels and deployable structures. Recent studies of these geometry families noticed that their convex pattern vertices enabled several further potential applications that were not otherwise possible with the concave vertices of more common pattern families such as Miura-type patterns. The following paper investigates one such application: the synthesis of folded frame structures from kirigami pattern geometric parametrisations. A new synthesis method is proposed for two geometries: a two-way orthogonal lattice frame generated from a kirigami cube pattern; and a multi-layer octahedral frame generated from a non-developable eggbox pattern. Both frames are developed with initial translation of folded geometries to frame element centre-lines and subsequent generation of integral frame elements with pattern sub-folds. Simple prototypes are manufactured to validate the synthesis method and it is found that the cube-generated frame compares favourable with typical frames with respect to packaging efficiency.
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Choi, Kyung K., and Byeng D. Youn. "Hybrid Analysis Method for Reliability-Based Design Optimization." In ASME 2001 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/detc2001/dac-21044.

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Abstract Reliability-Based Design Optimization (RBDO) involves evaluation of probabilistic constraints, which can be done in two different ways, the Reliability Index Approach (RIA) and the Performance Measure Approach (PMA). It has been reported in the literature that RIA yields instability for some problems but PMA is robust and efficient in identifying a probabilistic failure mode in the RBDO process. However, several examples of numerical tests of PMA have also shown instability and inefficiency in the RBDO process if the Advanced Mean Value (AMV) method, which is a numerical tool for probabilistic constraint evaluation in PMA, is used, since it behaves poorly for a concave performance function, even though it is effective for a convex performance function. To overcome difficulties of the AMV method, the Conjugate Mean Value (CMV) method is proposed in this paper for the concave performance function in PMA. However, since the CMV method exhibits the slow rate of convergence for the convex function, it is selectively used for concave-type constraints. That is, once the type of the performance function is identified, either the AMV method or the CMV method can be adaptively used for PMA during the RBDO iteration to evaluate probabilistic constraints effectively. This is referred to as the Hybrid Mean Value (HMV) method. The enhanced PMA with the HMV method is compared to RIA for effective evaluation of probabilistic constraints in the RBDO process. It is shown that PMA with a spherical equality constraint is easier to solve than RIA with a complicated equality constraint in estimating the probabilistic constraint in the RBDO process.
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Nagamura, Kazuteru, Kiyotaka Ikejo, Eiichirou Tanaka, Takamasa Hirai, Toshiyuki Koumori, and Ichiro Kamimura. "Driving Performance of High Reduction Planetary Gear Drive With Meshing of Arc Tooth Profile Gear and Pin Roller." In ASME 2007 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/detc2007-34245.

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This paper describes a new type planetary gear drive with the high reduction ratio. The planetary gear drive is mechanically similar to a 2S-C type planetary gear, which has two sun gears and one carrier. The planetary gear drive has two pairs of an arc tooth profile gear and a pin roller, which mesh each other. The planetary gear drive has little backlash, a high efficiency, a long fatigue limit, etc., because the tooth contact holds on concave and convex surfaces. In this study, we measured the vibration acceleration, the transmission error, the gear noise, and the efficiency on the new type planetary gear drive by the running test. We discuss and report the driving performance of the planetary gear drive.
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7

Ungur, Petru, Petru A. Pop, Mircea Gordan, Cornelia Gordan, and Mircea Veres. "Rational Using of Small Frontal Rigid Gear Couplings Type Gleason at Simple Direct and Differential Dividing and Geometrical Development of Smaller Size." In ASME 2008 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/detc2008-49448.

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This paper has presented two constructive solutions of rational using of frontal rigid gear couplings with spherical gear in circle arc type Gleason, knowing as curved frontal gear coupling, on small dimensions, ones for simple direct dividing and second for simple differential dividing, and geometrical development possibility of new family of frontal coupling and small size. The frontal gear coupling type Gleason are formed from two rings, one with concave gear and other with convex gear, being characterized by great twist moments of capacity transmission, realizing a precision angular position, fast central connection and assuring of optimal conditions for manufacturing of mass production and low cost. One new application of small frontal gear couplings was external diameter of O̸100mm and O̸120mm, assured a higher accuracy of angular location of ±2″ and a great carrying capacity for couplings by using of compound rest of lathe with ultra precision location. A second application has presented a new landing of simple direct and differential dividing using one or more pair of Gleason’s gear coupling due to construction of new indexing tables with ultra precision in metal cutting.
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8

Jain, Sakait, and Hae Chang Gea. "Two-Dimensional Packing Problems Using Genetic Algorithms." In ASME 1996 Design Engineering Technical Conferences and Computers in Engineering Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/96-detc/dac-1466.

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Abstract This paper presents a technique for applying genetic algorithms for the two dimensional packing problem. The approach is applicable to not only convex shaped objects, but, can also accommodate any type of concave and complex shaped objects including objects with holes. In this approach, a new concept of a two dimensional genetic chromosome is introduced. The total layout space is divided into a finite number of cells for mapping it into this 2-D genetic algorithm chromosome. The mutation and crossover operators have been modified and are applied in conjunction with connectivity analysis for the objects to reduce the creation of faulty generations. A new feature has been added to the genetic algorithm(GA) in the form of a new operator called compaction. Several examples of GA based layout are presented.
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Shamsuzzaman, M., Tatsuro Horie, Fusata Fuke, et al. "Experimental Evaluation of Debris Bed Characteristics in Particulate Debris Sedimentation Behaviour." In 2013 21st International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/icone21-15693.

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After a core-disruptive accident (CDA) in sodium-cooled fast reactor, degraded core material can form debris beds on core-support structure or in the lower inlet plenum of the reactor vessel. This paper reports an experimental evaluation on debris bed formation characteristic in CDA. Investigation of debris bed characteristic during debris sedimentation on core catcher plate is important from recriticality concern and also from cooling considerations to ensure the safety of the reactor main vessel in CDA. In the present study, to evaluate this characteristic, a series of experiments was performed by gravity driven discharge of solid particles as simulant debris from a nozzle into a quiescent water pool in isothermal condition at room temperature. The discharged solid particles with a maximum amount of 10 L finally accumulate on the debris tray, forming a bed with a convex or concave mound depending on the experimental parameters. The nozzle diameter, nozzle height, debris density, debris diameter and debris volume are taken as the experimental parameters. Currently, three types of spherical particles, namely Al2O3, ZrO2 and stainless steel (SS) with diameter of 2, 4, or 6 mm are employed to study the effect of key experimental parameter on debris bed mound shape. In addition, 2 mm non-spherical particles of SS were also utilized to investigate the effect of debris shape on altering mound profile. In experimental investigation with different debris volume, both developing and fully developed mound shapes were observed based on the effect of debris size, density and nozzle diameter. In this study, the investigated particle velocity of main stream settling particles was found increasing with nozzle diameter, which caused a decrement of mound height with an increment of mound dimple area. In nozzle height effect, shrinking of concavity on mound shape was observed with decreasing manner of impact velocity while height is reducing. From the visualization results of the experimental investigations, transformation of bed shape from convex to concave was observed with increasing repose angle incase of 4 mm Al2O3 particle. In general, transformation of bed shape was observed by increasing either nozzle diameter or particle density for all particle type. The present results could be useful to validate numerical models and simulation codes of particulate debris sedimentation.
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Chao, Li-Chi, and Chung-Biau Tsay. "Stress Analysis of Spherical Gear Sets." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-86843.

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The spherical gear is a new type of gear proposed by Mitome et al. [1]. Different from that of the conventional spur or helical gear sets, the spherical gear set can allow variable shaft angles and large axial misalignments without gear interference during the gear drive meshing [1, 2]. Geometrically, the spherical gear has two types of gear tooth profiles, the concave tooth and convex tooth. In practical transmission applications, the contact situation of a spherical gear set is very complex. To obtain a more realistic simulation result, the loaded tooth contact analysis (LTCA) has been performed by employing the finite element method (FEM). According to the derived mathematical model of spherical gear tooth surfaces, an automatic meshes generation program for three-dimensional spherical gears has been developed. Beside, tooth contact analysis (TCA) of spherical gears has been performed to simulate the contact points of the spherical gear set. Furthermore, the contact stress contours of spherical gear tooth surfaces and bending stress of tooth roots have been investigated by giving the design parameters, material properties, loadings and boundary conditions of spherical gears.
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