Tensile stress relaxation in unsaturated granular materials

The mechanics of granular media at low liquid saturation levels remain poorly understood. Macroscopic mechanical properties are affected by microscale forces and processes, such as capillary forces, inter-particle friction, liquid flows, and particle movements. An improved understanding of these microscale mechanisms is important for a range of industrial applications and natural phenomena (e.g. landslides). This study focuses on the transient evolution of the tensile stress of unsaturated granular media under extension. Experimental results suggest that the stress state of the material evolves even after cessation of sample extension. Moreover, we observe that the packing density strongly affects the efficiency of different processes that result in tensile stress relaxation. By comparing the observed relaxation time scales with published data, we conclude that tensile stress relaxation is governed by particle rearrangement and fluid redistribution. An increased packing density inhibits particle rearrangement and only leaves fluid redistribution as the major process that governs tensile stress relaxation.     

A participatory process for the design of housing for a First Nations Community

First Nation (Indigenous) on-reserve housing in Canada is in crisis due to severe shortages, high reported instances of mould contamination, overcrowding and structural deficiencies. The Kitamaat reserve of the Haisla First Nation provides one example. The intent of the study reported here was to engage with the Haisla to develop a culturally appropriate, environmentally responsive and energy-efficient housing type that the Haisla could implement in the future. This work was undertaken by Marceau-Evans-Johnson Architects in collaboration with researchers at the University of Victoria. In this article, the circumstances leading to the present housing crisis are reviewed, the consultative design process with the Haisla and its outcomes are described, and the concept design solution which was co-developed for future housing is presented.     

Fault diagnosis based on adaptive observer for a class of non-linear systems with unknown parameters

In this paper, the fault diagnosis problem for a class of non-linear systems with uncertainty which depends on states, inputs and unknown constant parameters is discussed. Under some geometric conditions, the system is transformed into two different subsystems. One is not affected by actuator faults, so a non-linear adaptive observer can be designed based on the assumption of the strictly positive realness (SPR). The other whose states can be measured is affected by the faults. Actuator fault diagnosis is based on estimations of both the state and the unknown parameters with good accuracy. Discussions on release of SPR requirement and extension to the sensor fault case are also made. Finally, two examples are given in order to illustrate the applicability of the proposed methods for actuator fault diagnosis and sensor fault diagnosis respectively.     

Computing the Output Distribution and Selection Probabilities of a Stack Filter from the DNF of Its Positive Boolean Function

Many nonlinear filters used in practise are stack filters. An algorithm is presented which calculates the output distribution of an arbitrary stack filter S from the disjunctive normal form (DNF) of its underlying positive Boolean function (PBF). Our algorithm avoids to enumerate the models of the PBF one by one, and thus is considerably more efficient than previous methods. The so called rank selection probabilities can be computed along the way.     

Zum Umgang mit ?kulturellen Fragen“ in der klinischen Ethik am Beispiel der Hymenrekonstruktion

Definition of the problem This paper illustrates a critical discussion of culture-related issues in clinical ethics with the example of hymen reconstruction. Arguments (1) To specifically discuss “culture-sensitive” issues in clinical ethics might perpetuate an essentialist understanding of culture. Instead this paper argues for a dynamic understanding of culture and generally context-sensitive, pluralist clinical ethics; (2) clinical ethics mainly focuses on the individual patient-physician relationship and public health ethics and global health ethics concentrate more on structural dimensions of health and health care. However, the interconnections should be acknowledged more systematically; (3) “migration” is often subsumed under “culture” as a bioethical issue. But the topics are not coextensive, instead both areas involve specific bioethical questions. More bioethical research is needed especially in the area of migration. On the basis of these three general aspects the paper discusses hymen reconstruction. It is argued that by performing the operation the physicians might perpetuate structural injustice and false anatomic beliefs, but that in some individual cases the operation can help prevent significant harm for the woman. Conclusion There has been an increasing awareness for “cultural” issues in health care and bioethics. It will be an ongoing challenge to perform “culture sensitive” health care without falling prey of essentialist othering and stereotyping. This paper argues for a general context sensitivity in a diverse, globalized world, where the connection of the individual health care to the structural circumstances are recognized. This understanding lays the ground for the argumentation of the specific case of hymen reconstruction.