A high-resolution scalable meshless method for coupled steady poroelastic analysis, based on collocation with radial basis functions

This work describes the application of a novel meshless numerical technique, based on local collocation with radial basis functions (RBFs), to the solution of steady poroelastic problems. Its formulation allows scalability to large problem sizes, in contrast to traditional full-domain RBF collocation methods which are restricted to small datasets due to issues with numerical conditioning and computational cost. The proposed method is validated using a benchmark linear elasticity numerical example and a coupled steady poroelastic deformation problem, for which analytical solutions are known. Highly accurate solutions are obtained in each case, and convergence rates in excess of sixth-order are observed

The family and romantic relationships of trans and gender diverse Australians: an exploratory survey

This is an Accepted Manuscript of an article published by Taylor & Francis in SEXUAL AND RELATIONSHIP THERAPY on 3 January 2015, available online: http://wwww.tandfonline.com/10.1080/14681994.2014.992409. Author version made available in accordance with the publisher's policy, under embargo for a period of 12 months from the date of publication.The present paper contributes an Australian focus to the growing body of research on trans and gender diverse people’s family and romantic relationships. A survey designed by the authors was completed by 160 trans or gender diverse Australians. A negative correlation was found between discrimination from families of origin and perceptions of support, and conversely a positive correlation was found between perceptions of support and emotional closeness. Analysis of open-ended responses suggested that support was primarily constituted by 1) emotional support, 2), utilising correct pronouns and names, and 3) financial support. Discrimination by families of origin was primarily constituted by 1) refusal to use correct pronouns and names, 2) exclusion from family events, and 3) pathologising responses. The findings in regards to romantic relationships suggest that trans women were more likely than trans men or gender diverse people to experience challenges in negotiating romantic relationships. A negative correlation was found between difficulties in negotiating romantic relationships and belief in the likelihood that an ‘ideal’ romantic relationship would occur in the future. Difficulties in negotiating romantic relationships were primarily described in terms of 1) anxiety over potential responses, 2) discrimination from potential partners, and 3) lack of self-acceptance. The paper concludes by discussing the implications of these findings for clinical practice

Schwarz alternating domain decomposition approach for the solution of mixed heat convection flow problems based on the method of approximate particular solutions

The incompressible two-dimensional Navier-Stokes equations including thermal energy balance equation are solved by the recently developed Method of Approximate Particular Solutions (MAPS). In a previous authors’ work this method was implemented to solve the two-dimensional Stokes equations by employing the pressure and velocity particular solutions obtained by Oseen’s decomposition with the Multiquadric (MQ) RBF as non-homogeneous term. A pressure-velocity linkage strategy is not required since the pressure particular solutions are obtained from the velocity ones. In the present contribution, the Navier-Stokes equations with Boussinesq approximation are solved by linearizing the convective term in a Picard iterative scheme. With the velocity values obtained at each of the Picard iterations, the energy conservation equation is solved by the MAPS by approximating temperature with the particular solutions of a Poisson problem with the MQ as a forcing term. With the aim of improving the computational efficiency of the global strategy, the two-dimensional domain is split into overlapped rectangular subdomains where the Schwarz Alternating Algorithm is employed to find a solution by using velocity and temperatures values from neighbouring zones as boundary conditions. The mixed convection lid-driven cavity flow problem is solved for moderate Reynolds and low Richardson numbers with the aim of validating the proposed method

CFD assessment of the effect of nanoparticles on the heat transfer properties of acetone/ZnBr2 solution

A potential novel working fluid for vapour absorption refrigeration utilising very low grade waste heat, is based on acetone and zinc bromide as the salt solution. A Computational Fluid Dynamics (CFD) model is presented of the fluid with zinc oxide nano-particles in a flat tube flow. A two phase type of model represents the zinc oxide nano-particles as a distinct fluid phase. The cases of laminar and turbulent flow are explored numerically for a wide range of acetone and nanoparticles concentrations. The velocity is varied between 1.5 and 6 ms−1, representing typical heat exchanger conditions. Reynolds number depends significantly on the solution concentration. Heat transfer coefficient increases with Re, by turbulent mixing, and with the concentration of nanoparticles and of acetone by the enhanced thermal diffusivity. The shear wall stress is not affected by changing the concentration of nano-particles. The nano-fluid is demonstrated to work well for heat transfer enhancement over the base fluid; the further issue of suspension of the nano-particles in the solution is explored experimentally. The nano-fluid can be achieved by ultra-sonic excitation, with a settling time in the order of several hours. Subject to the particle suspension time being increased, this fluid combination is a good candidate for the application considered

CFD multiphase modelling of the acetone condensation and evaporation process in a horizontal circular tube

With increasing demands on energy efficiency, the use of low grade waste heat using vapour absorption refrigeration systems (VARS) are receiving renewed interest. One idea is to use the combination of acetone and zinc bromide as the salt solution, which allows use of temperatures in the order of 10s of C above ambient conditions. This work numerically models acetone phase change in the evaporator and condenser in order to indicate how improvements can be made in these components of the system. ANSYS® Fluent finite volume method CFD is used to produce volume of fluid (VOF) and mixture multiphase flow models to investigate the evaporation and the condensation of acetone in a horizontal circular tube. Different velocities and temperatures were taken in each process to explore the effect of these variables in the system. A user defined function (UDF) is used to calculate the volume fraction of the phases. For the evaporation case, the heat transfer coefficient increases with increasing velocity and the temperature difference between the inlet flow and the wall, as expected. The mass transfer rate decreases with increasing the flow rate or decreasing the wall temperature, from 0.045 kg/m 3 .s at 0.01 m/s to 0.016 kg/m 3 .s at 0.06 m/s and it drops from 0.044 to 0.023 kg/m 3 .s by changing the temperature just from 300 to 298 K. This demonstrates a reduction in specific heat transfer to the liquid despite the higher wall heat transfer coefficient. In the condenser, vapour quality decreases along the tube as liquid acetone is created with reduced flow rate. Vapour volume fraction at the outlet section drops from 0.74 to 0.168 by increasing the ingoing velocity from 0.01 to 0.06 m/s. Increasing the rate of condensation will increase the liquid in the evaporator, which increase the evaporation rate then increase the performance of the VARS. This demonstrates the importance of controlling the temperature and the flow rate in the VARS for generate more refrigerants

Two dimensional solution of the advection-diffusion equation using two collocation methods with local upwinding RBF

The two-dimensional advection-diffusion equation is solved using two local collocation methods with Multiquadric (MQ)Radial Basis Functions (RBFs). Although both methods use upwinding, the first one, similar to the method of Kansa, approximates the dependent variable with a linear combination of MQs. The nodes are grouped into two types of stencil: cross-shaped stencil to approximate the Laplacian of the variable and circular sector shape stencil to approximate the gradient components. The circular sector opens in opposite to the flow direction and therefore the maximum number of nodes and the shape parameter value are selected conveniently. The second method is based on the Hermitian interpolation where the approximation function is a linear combination of MQs and the resulting functions of applying partial differential equation (PDE) and boundary operators to MQs, all of them centred at different points. The performance of these methods is analysed by solving several test problems whose analytical solutions are known. Solutions are obtained for different Peclet numbers, Pe, and several values of the shape parameter. For high Peclet numbers the accuracy of the second method is affected by the ill-conditioning of the interpolation matrix while the first interpolation method requires the introduction of additional nodes in the cross stencil. For low Pe both methods yield accurate results. Moreover, the first method is employed to solve the twodimensional Navier-Stokes equations in velocity-vorticity formulation for the lid-driven cavity problem moderate Pe

Solución bidimensional sin malla de la ecuación no lineal de convección-difusión-reacción mediante el método de Interpolación Local Hermítica

A meshless numerical scheme is developed for solving a generic version of the non-linear convection-diffusion-reaction equation in two-dimensional domains. The Local Hermitian Interpolation (LHI) method is employed for the spatial discretization and several strategies are implemented for the solution of the resulting non-linear equation system, among them the Picard iteration, the Newton Raphson method and a truncated version of the Homotopy Analysis Method (HAM). The LHI method is a local collocation strategy in which Radial Basis Functions (RBFs) are employed to build the interpolation function. Unlike the original Kansa’s Method, the LHI is applied locally and the boundary and governing equation differential operators are used to obtain the interpolation function, giving a symmetric and non-singular collocation matrix. Analytical and Numerical Jacobian matrices are tested for the Newton-Raphson method and the derivatives of the governing equation with respect to the homotopy parameter are obtained analytically. The numerical scheme is verified by comparing the obtained results to the one-dimensional Burgers’ and two-dimensional Richards’ analytical solutions. The same results are obtained for all the non-linear solvers tested, but better convergence rates are attained with the Newton Raphson method in a double iteration scheme.Se desarrolla un esquema numérico sin malla para resolver una versión genérica de la ecuación no lineal de convección-difusión-reacción en dominios bidimensionales. El método de Interpolación Hermitiana Local (LHI) se emplea para la discretización espacial y se implementan varias estrategias para la solución del sistema de ecuaciones no lineal resultante, entre ellas la iteración Picard, el método Newton Raphson y una versión truncada del Método de Análisis de Homotopía. (JAMÓN). El método LHI es una estrategia de colocación local en la que se utilizan funciones de base radial (RBF) para construir la función de interpolación. A diferencia del método original de Kansa, el LHI se aplica localmente y los operadores diferenciales de ecuación límite y gobernante se utilizan para obtener la función de interpolación, dando una matriz de colocación simétrica y no singular. Las matrices analíticas y numéricas jacobianas se prueban para el método de Newton-Raphson y las derivadas de la ecuación de gobierno con respecto al parámetro de homotopía se obtienen analíticamente. El esquema numérico se verifica comparando los resultados obtenidos con las soluciones analíticas unidimensionales de Burgers y Richards bidimensionales. Se obtienen los mismos resultados para todos los solucionadores no lineales probados, pero se obtienen mejores tasas de convergencia con el método Newton Raphson en un esquema de doble iteración

Imagining parenthood: the possibilities and experiences of parenthood among transgender people

Abstract This paper reports on a qualitative study exploring the ways in which transgender adults imagine a place for parenthood in their lives, and/or the ways they have negotiated parenthood with their transgender identity. A total of 13 transgender adults (including parents and non-parents) were interviewed with respect to their thoughts and experiences about family, relationships and parenting. The study sought to understand the possibilities for parenthood that transgender people create, despite barriers imposed by restrictive laws, medical practices and cultural attitudes. Interview data showed how normative assumptions about gender and parenthood shape the way people imagined and desired parenthood. It also showed how participants re-appropriated and resisted normative cultural scripts by either reimagining parenthood in different terms (such as step-parenthood) or by creating different family forms, such as co-parented families. Participants reported a variety of experiences with healthcare providers when it came to conversations about fertility preservation and family building

Microremains from El Mirón Cave human dental calculus suggest a mixed plant/animal subsistence economy during the Magdalenian in Northern Iberia

Despite more than a century of detailed investigation of the Magdalenian period in Northern Iberia, our understanding of the diets during this period is limited. Methodologies for the reconstruction of Late Glacial subsistence strategies have overwhelmingly targeted animal exploitation, thus revealing only a portion of the dietary spectrum. Retrieving food debris from calculus offers a means to provide missing information on other components of diet.We undertook analysis of human dental calculus samples from Magdalenian individuals (including the ¿Red Lady¿) at El Mir on Cave (Cantabria, Spain), as well as several control samples, to better understand the less visible dietary components. Dental calculus yielded a diverse assemblage of microremains from plant, fungal, animal and mineral sources that may provide data on diet and environment. The types of microremains show that the individuals at El Mir on consumed a variety of plants, including seeds and underground storage organs, as well as other foods, including possibly bolete mushrooms. These findings suggest that plant and plant-like foods were parts of her diet, supplementing staples derived from animal foods. As faunal evidence suggests that the Magdalenian Cantabrian diet included a large proportion of animal foods, we argue here for a mixed subsistence pattern

On the dynamics of a high-speed coned fluid-lubricated bearing

An incompressible air-flow model for a fluid film bearing is derived using a modified Reynolds equation for the thin-film dynamics of a rapidly rotating rotor and stator. Mathematical and numerical modelling is applied to the coupled processes of the fluid flow through the bearing and the axial motion of the rotor and stator. This work focuses on extending previous studies to incorporate the dynamics of a coned rotor operating at high speeds and an incompressible lubrication approximation. The dynamics of fully coupled, unsteady bearing motion and associated forcing of the rotor with axial periodic oscillations are studied. The axial motion of the stator is modelled as a spring–mass–damper system that responds to the rotor displacement through the film dynamics. In order to solve the modified Reynolds equation and stator equation simultaneously, a new variable is introduced, namely the time-dependent face clearance. This leads to explicit analytical expressions for the pressure and force in terms of the face clearance and the stator equation is transformed to a non-linear, second-order, non-autonomous, ordinary differential equation for the face clearance. Applying a transient solver gives solutions settling down to a stable periodic behaviour which motivates seeking a solver for periodic solutions. A Fourier spectral collocation scheme is derived to compute the periodic time-dependent face clearance. Both solvers have matching periodic solutions of O(1) with an absolute error of order of magnitude 10−5. The dynamics of the unsteady bearing are examined for a range of pressure gradients and configurations including an asymptotic investigation of small face clearance associated with a start-up transient. Results are provided relating to changes in the width of the bearing, strength of the spring holding stator to its housing, damping of the stator and strength of the force coupling and rotor mass. The dynamics of the bearing are also investigated relative to values of key system parameters including the coning of the rotor, rotation speed and value of the bearing squeeze number. A parameter investigation is undertaken to highlight ideal bearing configurations to maximize the load-carrying capacity, fluid stiffness and damping