Numerical estimation of 3D mechanical forces exerted by cells on non-linear materials

The exchange of physical forces in both cell-cell and cell-matrix interactions play a significant role in a variety of physiological and pathological processes, such as cell migration, cancer metastasis, inflammation and wound healing. Therefore, great interest exists in accurately quantifying the forces that cells exert on their substrate during migration. Traction Force Microscopy (TFM) is the most widely used method for measuring cell traction forces. Several mathematical techniques have been developed to estimate forces from TFM experiments. However, certain simplifications are commonly assumed, such as linear elasticity of the materials and/or free geometries, which in some cases may lead to inaccurate results. Here, cellular forces are numerically estimated by solving a minimization problem that combines multiple non-linear FEM solutions. Our simulations, free from constraints on the geometrical and the mechanical conditions, show that forces are predicted with higher accuracy than when using the standard approaches.

On the two-dimensional thermoelectric power in quantum wells of non-parabolic materials under magnetic quantization

We present a simplified theoretical formulation of the thermoelectric power (TP) under magnetic quantization in quantum wells (QWs) of nonlinear optical materials on the basis of a newly formulated magneto-dispersion law. We consider the anisotropies in the effective electron masses and the spin-orbit constants within the framework of k.p formalism by incorporating the influence of the crystal field splitting. The corresponding results for III-V materials form a special case of our generalized analysis under certain limiting conditions. The TP in QWs of Bismuth, II-VI, IV-VI and stressed materials has been studied by formulating appropriate electron magneto-dispersion laws. We also address the fact that the TP exhibits composite oscillations with a varying quantizing magnetic field in QWs of n-Cd3As2, n-CdGeAs2, n-InSb, p-CdS, stressed InSb, PbTe and Bismuth. This reflects the combined signatures of magnetic and spatial quantizations of the carriers in such structures. The TP also decreases with increasing electron statistics and under the condition of non-degeneracy, all the results as derived in this paper get transformed into the well-known classical equation of TP and thus confirming the compatibility test. We have also suggested an experimental method of determining the elastic constants in such systems with arbitrary carrier energy spectra from the known value of the TP. (C) 2010 Elsevier Ltd. All rights reserved.

Micromechanical Modelling of Non-Homogenous Materials by Meshless Methods

A detailed study of bi-material composites, using meshless methods (MMs), is presented in this paper. Firstly, representative volume elements (RVEs) for different bi-material combinations are analysed by the element-free Galerkin (EFG) method in order to confirm the effective properties of heterogeneous material through homogenization. The results are shown to be in good agreement with experimental results and those obtained using the finite element method (FEM) which required a higher node density. Secondly, a functionally graded material (FGM), with a crack, is analysed using the EFG method. This investigation was motivated by the possibility of replacing the distinct fibrematrix interface with a FGM interface. Finally, an illustrative example showing crack propagation, in a two-dimension micro-scale model of a SiC/Al composite is presented. 

Non-destruct|ve testing of non-metallic materials using microwaves

The motivatitni for" the present work is from .a project sanctioned by TSRO. The work involved the development of a quick and reliable test procedure using microwaves, for tflue inspection of cured propellant samples and a method to monitor the curing conditions of propellant mix undergoing the curing process.Normal testing CHE the propellant samples involvecuttimg a piece from each carton and testing it for their tensile strength. The values are then compared with standard ones and based on this result the sample isaccepted or rejected. The tensile strength is a measure ofdegree of cure of the propellant mix. But this measurementis a destructive procedure as it involves cutting of the sample. Moreover, it does not guarantee against nonuniform curing due to power failure, hot air-line failure,operator error etc. This necessitated the need for the development of a quick and reliable non-destructive test procedure.

FEA simulation of contact and wear between non-metallic materials for accelerated new product development

The conventional approach ie laboratory life testing to examine the reliability of products takes long time and involves tremendous cost as samples are tested till failures. The accelerated life test (ALT) has recently been used as an alternative method. Although ALT reduces the cost of reliability testing through applying more severe environmental conditions than the normal ones, it is no longer sufficient as it does not describe the process of products’ failure explicitly and it is still highly dependent on physical testing. Consequently, novel practices need to be developed for better understanding of the products’ reliability. A novel Finite Element Analysis (FEA) model incorporating mathematical wear equations is developed in the current work and applied to polymer materials. Wear rate, a key parameter, is calculated by using a combinatorial formula that combines a conventional linear equation with a recently published exponential equation. The local wear is firstly calculated and then integrated over the sliding distance. The FEA simulation works in a loop and performs a series of simulation with updated surface geometries. The simulation is in good agreement with the physical testing result.

Problems in bibliographic access to non-print materials : final report /

Mode of access: Internet.

Waveguide fabrication in lithium-niobo-phosphate glasses by high repetition rate femtosecond laser:route to non-equilibrium material’s states

We study waveguide fabrication in lithium-niobo-phosphate glass, aiming at a practical method of single-stage fabrication of nonlinear integrated-optics devices. We observed chemical transformations or material redistribution during the course of high repetition rate femtosecond laser inscription. We believe that the laser-induced ultrafast heating and cooling followed by elements diffusion on a microscopic scale opens the way toward the engineering non-equilibrium sates of matter and thus can further enhance Refractive Index (RI) contrasts by virtue of changing glass composition in and around the fs tracks. © 2014 Optical Society of America.

Crack propagation in non-homogenous materials: Evaluation of mixed-mode SIFs, T-stress and kinking angle using a variant EFG method

A new variant of the Element-Free Galerkin (EFG) method, that combines the diffraction method, to characterize the crack tip solution, and the Heaviside enrichment function for representing discontinuity due to a crack, has been used to model crack propagation through non-homogenous materials. In the case of interface crack propagation, the kink angle is predicted by applying the maximum tangential principal stress (MTPS) criterion in conjunction with consideration of the energy release rate (ERR). The MTPS criterion is applied to the crack tip stress field described by both the stress intensity factor (SIF) and the T-stress, which are extracted using the interaction integral method. The proposed EFG method has been developed and applied for 2D case studies involving a crack in an orthotropic material, crack along an interface and a crack terminating at a bi-material interface, under mechanical or thermal loading; this is done to demonstrate the advantages and efficiency of the proposed methodology. The computed SIFs, T-stress and the predicted interface crack kink angles are compared with existing results in the literature and are found to be in good agreement. An example of crack growth through a particle-reinforced composite materials, which may involve crack meandering around the particle, is reported.

How to optimize operational shipping processes of non-production materials? The Volkswagen Autoeuropa case study

Field lab: Entrepreneurial and innovative ventures

Aplicación de las herramientas de la web 2.0 a la enseñanza de la catalogación de documentos

En este trabajo se plantea la elaboración de un proyecto de intervención que se dirige a modificar la metodología de enseñanza para el procesamiento de documentos en el ámbito de la asignatura Procesamiento de Materiales Especiales de la carrera de Bibliotecología y Ciencia de la Información que se dicta en la Facultad de Humanidades y Ciencias de la Educación. A tal efecto se plantea introducir en el entorno de enseñanza aprendizaje las herramientas de las web 2.0 aplicadas a los entornos catalográficos, que en conjunto se denomina OPAC 2.0. Esta innovación en el entorno de la mencionada asignatura supone una innovación ya que hasta el momento este tipo de metodología, si bien desarrollada en el procesamiento de documentos en el ámbito del ejercicio profesional, no ha sido incorporada en la asignatura como parte del proceso de enseñanza

Aplicación de las herramientas de la web 2.0 a la enseñanza de la catalogación de documentos

En este trabajo se plantea la elaboración de un proyecto de intervención que se dirige a modificar la metodología de enseñanza para el procesamiento de documentos en el ámbito de la asignatura Procesamiento de Materiales Especiales de la carrera de Bibliotecología y Ciencia de la Información que se dicta en la Facultad de Humanidades y Ciencias de la Educación. A tal efecto se plantea introducir en el entorno de enseñanza aprendizaje las herramientas de las web 2.0 aplicadas a los entornos catalográficos, que en conjunto se denomina OPAC 2.0. Esta innovación en el entorno de la mencionada asignatura supone una innovación ya que hasta el momento este tipo de metodología, si bien desarrollada en el procesamiento de documentos en el ámbito del ejercicio profesional, no ha sido incorporada en la asignatura como parte del proceso de enseñanza

Aplicación de las herramientas de la web 2.0 a la enseñanza de la catalogación de documentos

En este trabajo se plantea la elaboración de un proyecto de intervención que se dirige a modificar la metodología de enseñanza para el procesamiento de documentos en el ámbito de la asignatura Procesamiento de Materiales Especiales de la carrera de Bibliotecología y Ciencia de la Información que se dicta en la Facultad de Humanidades y Ciencias de la Educación. A tal efecto se plantea introducir en el entorno de enseñanza aprendizaje las herramientas de las web 2.0 aplicadas a los entornos catalográficos, que en conjunto se denomina OPAC 2.0. Esta innovación en el entorno de la mencionada asignatura supone una innovación ya que hasta el momento este tipo de metodología, si bien desarrollada en el procesamiento de documentos en el ámbito del ejercicio profesional, no ha sido incorporada en la asignatura como parte del proceso de enseñanza

Book of A.S.T.M. standards.

Part of illustrative matter is folded.

The increased flammability of metallic materials burning in reduced gravity

Data generated in a normal gravity environment is often used in design and risk assessment for reduced gravity applications. It has been clearly demonstrated that this is a conservative approach for non-metallic materials which have been repeatedly shown to be less flammable in a reduced gravity environment. However, recent work has demonstrated this is not true for metallic materials. This work, conducted in a newly completed drop tower observed a significant increase in both lowest burn pressure and burn rate in reduced gravity. Hence the normal gravity qualification of a metallic materials’ lowest burn pressure or burn rate for reduced-gravity or space-based systems is clearly not conservative. This paper presents a summary of this work and the results obtained for several metallic materials showing an increased flammability and burn rate for a range of oxygen pressures, and discusses the implications of this work on the fire-safety of space-based systems.