Identifying patients at risk for augmented renal clearance in the ICU : limitations and challenges

Augmented renal clearance (ARC) is an important determinant of antibiotic exposure in critically ill patients, and identifying patients at risk is therefore an important goal. There is a growing body of evidence that a younger patient with a low to moderate degree of organ dysfunction typically is at risk of ARC and therefore decreased exposure to renally eliminated antibiotics. Mechanisms potentially involved, such as increased cardiac output, have, however, not been identified as appropriate surrogate markers, and the search for suitable alternatives to readily identify patients with ARC continues

Comment on the paper entitled 'A new cumulative fatigue damage rule based on dynamic residual S-N curve and material memory concept' by Peng Z., Huang H., Zhou J. and Li Y. Published in Metals (2018; 8 (6): 456)

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Design of a four-point bend test for ultra-low cycle fatigue of pipelines under inelastic bending

This master thesis is situated in the research domain dealing with the ductile failure of pipelines under extreme loading conditions. It is part of an umbrella research aiming to develop innovative experimental and computational methodologies to simulate fracture of steel structural elements under ultralow cycle fatigue. The focus of this study is on steel pipeline applications. The objective of this thesis is to design a large-scale four-point bend test setup to cyclically bend pipes. The feasibility of instrumentation will be evaluated using small scale test specimens. In this paper some ideas, constraints and opportunities for the design are considered, based on a literature review of several test setups for other applications. The design parameters have been calculated to compose the design windows and an initial overview of the possible instrumentation is given

Development of a continuum plasticity model for the commercial finite element code ABAQUS

The present work relates to the development of computational material models for sheet metal forming simulations. In this specific study, an implicit scheme with consistent Jacobian is used for integration of large deformation formulation and plane stress elements. As a privilege to the explicit scheme, the implicit integration scheme is unconditionally stable. The backward Euler method is used to update trial stress values lying outside the yield surface by correcting them back to the yield surface at every time increment. In this study, the implicit integration of isotropic hardening with the von Mises yield criterion is discussed in detail. In future work it will be implemented into the commercial finite element code ABAQUS by means of a user material subroutine

Towards better finite element modelling of elastic recovery in sheet metal forming of advanced high strength steel

The first part of this study discusses the influence of element type on parameters such as accuracy of the FE simulation, simulation time and convergence. Guidelines on optimal implementation of element types are proposed. It is shown that an inappropriate choice of element type results in difficulties in convergence of the simulation or gives rise to problems such as shear locking in elements. In the second part of this study a series of finite element simulations using the Hill’48 planar anisotropic yield criterion and a standard U-shape forming test based on the NUMISHEET’93 benchmark was performed. The effectiveness of different isotropic hardening laws and different contact models is investigated. The most appropriate hardening and contact definitions are defined from the viewpoint of optimal springback prediction. Finally, the influence of the orientation of sheet strips relative to the rolling direction on springback angles is evaluated

Review and classification of fretting fatigue test rigs

There is no standard or generally accepted test rig for fretting fatigue experiments. Therefore, researchers adopt an existing concept, or build a new test rig that meets their specific requirements. However, too many different test rigs may be disadvantageous because the results of two different test rigs are hard to compare. The increasing amount of diversity is mainly caused by the lack of a recent literature survey on fretting fatigue test rigs. In 1994, Hills and Nowell described a few test rigs in Mechanics Of Fretting Fatigue. In this study, the authors made a classification of test rigs based on the contact geometry, which is determined by the test specimens, not by the test rig itself. The authors of this article present a review of the available literature, and present a classification based on the properties of test rigs. Fretting fatigue test rigs are first divided in two categories based on the geometry of the test specimen: full scale and coupon scale test rigs. The latter are mostly used to perform research and are subdivided in categories based on increasing functionalities. This is the ability to apply a fatigue load, a constant normal force, and an alternating slip in the range of some micrometers. In time, from the fifties until now, progress has been seen in the design of fretting fatigue test rigs. More parameters can be controlled during experiments and more measuring techniques are incorporated. State of the art test rigs are classified in the last category with mostffunctionalities, but still have imperfections. Future designers can use this article to classify their needs, or help to design a better test rig knowing the imperfections of the state of the art test rigs