Search

Treatment options for refractory neurogenic detrusor overactivity (NDO) in children include botulinum toxin type A (BTX-A) and augmentation cystoplasty (AC). Although BTX-A is accepted in contemporary pediatric urologic practice, cost and long-term outcomes data for BTX-A are limited relative to the gold standard, AC. The purpose of this study was to compare the projected 10-year costs of AC versus BTX-A.We performed a cost analysis from the payer perspective by computationally modeling treatment sequences by a Markov model. In the model, we used probabilities derived from published sources, and costs obtained at a tertiary medical center. The base case was a pediatric patient with refractory NDO. In the model, we assumed biannual BTX-A treatments. Treatment costs over 10 years were compared between immediate AC versus bridging therapy with BTX-A. Using the computational model, we simulated 100,000 instances of 10-year treatment cost for each of the two treatment modalities. The costs for the two treatment approaches were then compared using t-test and Wilcoxon test.The projected median and mean 10-year cost of immediately AC were $51,798.72 (95% CI [$51,798.72, $327,483.80]) and $123,473.4 (SD: $98,085.23) respectfully, while the projected median and mean 10-year cost of bridging therapy with BTX-A prior to proceeding to AC as needed were $74,552.46 (95% CI [$53,188.56, $309,913.07]) and $124,858.80 (SD: $84,495.35) (p 0.001).For a typical index pediatric patient with NDO, bridging therapy with intravesical BTX-A is associated with an increased cost compared to immediate AC over a ten-year period.

Two full-scale timbrel cross vaults subjected to vertical settlements in one of their supports were tested at the ICITECH laboratories of the Universitat Politècnica de València. In one of the vaults a support was moved downwards, while the other was subjected to upward-downward displacements in one support. Both tests are described and analysed in detail in Torres et al. [1,2]. Both vaults presented certain levels of post-test damage in the form of cracks and significant displacements. In order to analyse the effectiveness of the reinforcement of previously damaged vaults, both were strengthened with TRM and subjected to further testing in which vertical settlements were applied to one support. The TRM strengthening comprised an extrados layer composed of a 25x25mm glass grid embedded into two approximately 5 mm thick layers of cementitious matrix. The TRM strengthening was able to withstand higher peak loads and prevent the formation of cracks along the extrados surface of the structure, while as expected, ductility increased. A 3D macro-modelling FE strategy on Abaqus commercial software was also adopted to study the behaviour of the vaults during the tests.

The first paper on isogeometric analysis appeared only five years ago [1], and the first book appeared last year [2]. Progress has been rapid. Isogeometric analysis has been applied to a wide variety of problems in solids, fluids and fluid-structure interactions. Superior accuracy to traditional finite elements has been demonstrated in all cases. In addition, it has been shown that isogeometric analysis provides an efficient framework for the design through analysis paradigm. In this contribution we present two examples which illustrate the potential of T-splines, a powerful generalization of NURBS, the CAD industry standard. The first example utilizes T-splines for a problem of propagating cracks. Smoothly turning discontinuities can be introduced in T-splines through local knot insertion. The possibility of enhancing a T-spline basis with discontinuities makes isogeometric finite elements suitable for the capturing of discontinuities, in particular, cracks. From an implementation point of view, the concept of Bézier extraction [3] allows for a unified approach to NURBS and T-splines, and will allow this approach to be extended to T-splines of arbitrary topology. The second example demonstrates the enabling power of T-splines in a design through analysis framework. A trimless T-spline automotive bumper is generated and then used directly in an LS-DYNA vibrations analysis [4]. T-splines can describe shapes of arbitrary topological complexity while maintaining a smooth analysis-suitable basis. This makes them an attractive alternative to classical finite elements for many problems of engineering interest. For such problems, the isogeometric paradigm can be invoked thus eliminating the analysis costs associated with geometry clean-up, defeaturing and mesh generation. The two numerical simulations considered in this work demonstrate the capability of the T-spline basis to meet the stringent needs of analysis while providing the flexibility to overcome design through analysis bottlenecks. Specifically, T-splines were found to give efficient discretizations in terms of the number of degrees of freedom and the required computational effort. We anticipate that T-splines and isogeometric analysis will continue to provide efficient solutions to many important problems in computational mechanics.

In this paper the problem of using displacement influence lines to detect, locate and evaluate degree of damage in beam structures is investigated. The displacement influence line curvature enables locating the damaged section reliably. But the curvature method is not always reliable for damage evaluation. Changes in the displacement influence line curvatures are caused by changes in the bending moment and the bending stiffness. In static undetermined systems, theoretically, change in bending stiffness cause change in bending moment as well. Therefore, the strain energy method has been applied to evaluate rate of damage in the damaged section. The main advantage of the presented method is a need for only a few measuring points in the structure.

A high DC magnetic field can be used to levitate liquid droplets in terrestrial conditions, as is known from experiments [1,2]. The DC magnetic levitation mechanism is considerably different from the AC case [3], where an intense turbulent flow is generated as a consequence of the rotational nature of the electromagnetic force. In DC magnetic levitation the force distribution is a potential function, which permits analytical solutions in particular cases [4]. The dynamic interactions of the flow with the oscillating interface, confined by the magnetic force, are analysed using a multi-physics numerical model for simulating the time dependent liquid metal and the magnetic field generated by currents in the coil system [5]. The numerical simulations demonstrate the possibility of levitating diamagnetic droplets in strictly controllable conditions permitting the material properties measurement from experimental observations.\ud \ud Two different coil arrangements are analysed using the numerical code to model the DC magnetic levitation of a water droplet. The levitation of liquid in controllable conditions is achievable but requires careful optimisation of the electromagnetic and gravity force balance. The fluid velocities, generated by the magnetic force modification due to the liquid surface oscillation in the strong gradient field, are small in magnitude and remain in the laminar regime.

This paper shows application of spectral method in dynamic of structures subjected to a moving load. The idea of finite strips formulation has been used to formulate novel element based on spectral discretization in one dimension. Equations of structural dynamics require no adaptation in order to be solved using this procedure. The presented approach is general in its formulation and can be used for other types of structural analysis.

It is well known from experiments and industrial applications of cold crucible melting that an intense AC magnetic field can be used to levitate large volumes of liquid metal in the terrestrial conditions. The levitation confinement mechanism for large volumes of fluid is considerably different from the case of a small droplet where surface tension plays a key role in constraining the liquid outflow at the critical bottom point. The dynamic interaction between the oscillatory motion of the free surface and the effects of turbulent flow is analysed using a unified numerical model which describes the time dependent behaviour of the liquid metal and the magnetic field. The MHD modified k-omega turbulence model is used to describe the mixing and damping properties at smaller scales not resolved by the macro model. The numerical multiphysics simulations suggest that it is possible to levitate a few kilograms of liquid metal in a cold crucible without requiring mechanical support from the container walls. Possible applications to the processing of reactive metals are discussed.