Letters from the chairman of the summer school committee

Letters concerning the summer school of Utah Agricultural College

Nonlocal regularization for loss of ellipticity in inelastic problems

A mixed three-field finite element formulation is proposed as a method for the alleviation of mesh dependency in finite-deformation inelastic problems subjected to bifurcation. The additional fields in the formulation are the internal variables that cause bifurcation and the corresponding conjugate thermodynamic forces. The formulation leads to expressions for the additional fields that are akin to nonlocal averages that extend to a domain defined by the interpolation functions selected for these fields. The size of the nonlocal domain controls the length scale of the problem. The performance of the formulation is demonstrated by several examples where it is shown that it is effective in alleviating mesh dependence. The formulation provides effective regularization, entirely by-passes the introduction of new and independent mechanical variables into the problem, discretizes naturally, computes averages with regular interpolation functions, and does not require changes to constitutive relationships

Modeling the hydro-mechanical responses of strip and circular punch loadings on water-saturated collapsible geomaterials

A stabilized enhanced strain finite element procedure for poromechanics is fully integrated with an elasto-plastic cap model to simulate the hydro-mechanical interactions of fluid-infiltrating porous rocks with associative and non-associative plastic flow. We present a quantitative analysis on how macroscopic plastic volumetric response caused by pore collapse and grain rearrangement affects the seepage of pore fluid, and vice versa. Results of finite element simulations imply that the dissipation of excess pore pressure may significantly affect the stress path and thus alter the volumetric plastic responses

L'application du droit penal islamique dans le Nord-Nigeria

Cet article etudie l'application du code penal islamique dans le Nord-Nigeria ainsi que les programmes de mise en oeuvre de la charia lances dans douze Etats du Nord en 1999-2000. Les nouvelles lois du Code penal islamique promulguees par les douze Etats pratiquant la charia sont detaillees pour exposer les anomalies constitutionnelles liees a leur application. Se distingue le fait que les sentences severes prononcees par les tribunaux de la charia ne sont pas executees, ce qui aboutit a une situation ou des personnes jugees coupables purgent des peines d' emprisonnement auxquelles elles n'ont pas ete condamnees. L'article examine les approches qui seront envisagees pour traiter ce probleme a moyen terme et le resoudre sur le long terme.Rule of Law and Development: Formation, Implementation and Improvement of Law and Governance in Developing Countrie

Lie-group interpolation and variational recovery for internal variables

We propose a variational procedure for the recovery of internal variables, in effect extending them from integration points to the entire domain. The objective is to perform the recovery with minimum error and at the same time guarantee that the internal variables remain in their admissible spaces. The minimization of the error is achieved by a three-field finite element formulation. The fields in the formulation are the deformation mapping, the target or mapped internal variables and a Lagrange multiplier that enforces the equality between the source and target internal variables. This formulation leads to an L2 projection that minimizes the distance between the source and target internal variables as measured in the L2 norm of the internal variable space. To ensure that the target internal variables remain in their original space, their interpolation is performed by recourse to Lie groups, which allows for direct polynomial interpolation of the corresponding Lie algebras by means of the logarithmic map. Once the Lie algebras are interpolated, the mapped variables are recovered by the exponential map, thus guaranteeing that they remain in the appropriate space

Albany: Using Component-based Design to Develop a Flexible, Generic Multiphysics Analysis Code

Abstract: Albany is a multiphysics code constructed by assembling a set of reusable, general components. It is an implicit, unstructured grid finite element code that hosts a set of advanced features that are readily combined within a single analysis run. Albany uses template-based generic programming methods to provide extensibility and flexibility; it employs a generic residual evaluation interface to support the easy addition and modification of physics. This interface is coupled to powerful automatic differentiation utilities that are used to implement efficient nonlinear solvers and preconditioners, and also to enable sensitivity analysis and embedded uncertainty quantification capabilities as part of the forward solve. The flexible application programming interfaces in Albany couple to two different adaptive mesh libraries; it internally employs generic integration machinery that supports tetrahedral, hexahedral, and hybrid meshes of user specified order. We present the overall design of Albany, and focus on the specifics of the integration of many of its advanced features. As Albany and the components that form it are openly available on the internet, it is our goal that the reader might find some of the design concepts useful in their own work. Albany results in a code that enables the rapid development of parallel, numerically efficient multiphysics software tools. In discussing the features and details of the integration of many of the components involved, we show the reader the wide variety of solution components that are available and what is possible when they are combined within a simulation capability. Key Words: partial differential equations, finite element analysis, template-based generic programmin

Historical Missionary Activity, Schooling, and the Reversal of Fortunes: Evidence from Nigeria

This paper shows that historical missionary activity has had a persistent effect on schooling outcomes, and contributed to a reversal of fortunes wherein historically richer ethnic groups are poorer today. Combining contemporary individual-level data with a newly constructed dataset on mission stations in Nigeria, we find that individuals whose ancestors were exposed to greater missionary activity have higher levels of schooling. This effect is robust to omitted heterogeneity, ethnicity fixed effects, and reverse causation. We find inter-generational factors and the persistence of early advantages in educational infrastructure to be key channels through which the effect has persisted. Consistent with theory, the effect of missions on current schooling is larger for population subgroups that have historically suffered disadvantages in access to education