On the failure of silicone breast implants: new insights by mapping the mechanical properties of implant shells

This review summarizes the knowledge on rupture (in vivo as well as under laboratory conditions) of gel‐filled silicone breast implants, which has been an open question since the first implantation in 1962. We present recent progress which has been made by a mapping of the mechanical properties of the shell material together with a statistical failure analysis by means of a Weibull fit. Reference implants and intact as well as ruptured explants are tested after several years in vivo using tensile tests. Up to 110 dumbbell‐shaped specimens per implant are measured allowing a detailed mapping of the mechanical properties of the silicone shell. Therefore, it is possible to illustrate the results of the tensile tests by mapping the measured values of the implants in the form of a contour plot revealing novel insights. The contour plots clearly display that the mechanical behaviour (e.g. stress at break) varies significantly over the shell. Additionally, a map is proposed which clearly shows separated clusters for different manufacturers and product categories. © 2013 Society of Chemical Industry     

Concept study of a new method for drying dishware in a heat pump dishwasher

In a heat pump dishwasher, the whole dishwasher with the cabinet, dishware and process water is the heat sink, while a water tank, whose contents will freeze, is the heat source. The aim of the experimental concept study presented here was to evaluate a new drying method for a heat pump dishwasher. In this method, the drying of the dishware occurs as a fan circulates humid air in a closed system in which the water on the dishware evaporates inside the warm dishwasher cabinet and then condenses on a cold surface of the frozen water tank. The evaluation of drying performance was based on the European standard EN50242, which considers visible water drops left on the dishware after a completed dishwashing cycle. The results showed that this new closed drying method was more energy efficient compared to an existing open drying method and that the drying start temperature and the drying time had a significant effect on the drying performance. Its lower electricity consumption and the fact that it does not vent humid air into the kitchen give this heat pump dishwasher a competitive advantage over dishwashers using an open drying method.     

Project managers and career models: An exploratory comparative study

Prior research has paid little attention to the careers and career models of project managers. This is troublesome for at least two reasons. First, project managers are becoming an increasingly important category of managers and today they constitute a major part of many organizations' leadership capability. Second, traditional literature on careers generally does not address project-based careers as a specific case in point, although this kind of career is unique in the sense that it is based on temporary assignments and lack of formal positions. The research presented in this paper identifies and explains patterns of similarities and differences among applied career models in ten large, mature project-intensive firms in Sweden. The paper identifies a number of factors that seem to be critical for the design of career models for project managers, including the number of levels, the complexity of assignments, and the degree of formal requirements. The paper also outlines two archetypes of career models applied by the firms under study: the competence strategy model and the talent management model.     

Microalgae biodiesel via in situ methanolysis

BACKGROUND: Microalgae have recently been considered a potential feedstock for biodiesel production, since they do not compete with agricultural land, unlike oil crops. However, the production processes must be energetically and economically viable. Therefore, an in situ methanolysis process is proposed for biodiesel production directly from microalgae biomass, to avoid the need for the separation and extraction steps. RESULTS: Biodiesel was obtained using methanol as the methylation reactant for the transesterification reaction and hydrochloric acid as the catalyst precursor, at 80 °C for 2 h of reaction. A mass return of 23.07 ± 2.76% (m/m) was obtained. Spectrometry in the infrared region showed that the product had equivalent bands of axial deformation of C?O, C? O and C? H, i.e. an ester. Tests showed the chromatographic profile of fatty acids in the sample. A process energetic efficiency value of 1.17 was obtained for microalgae derived biodiesel, which is higher than from soybean and sunflower, reportedly 1.06 and 1.12. CONCLUSIONS: Industrial sustainability results from low energetic, economic and environmental losses. The microalgae in situ methanolysis process showed greater fuel available energy than energy consumption, therefore is energetically sustainable. Economic and environmental issues should still be addressed. Copyright © 2011 Society of Chemical Industry     

Domain and requirements for a wearable-based doping control system

In Germany, over 7000 professional athletes from different sport sectors must undergo regular doping controls. As is the case with many other nations, Germany relies upon a system recommended by the World Anti-Doping Agency (WADA) to coordinate and initiate these controls. Known as the Anti-Doping Admission and Administration System, or ADAMS for short, the system requires athletes to submit their future regular whereabouts via browser, up to three months in advance. This allows the Doping Control Officer (DCO) to be able to locate the athlete without prior notice. The flip side, however, is that, since its introduction in 2007, ADAMS has not only been severely criticized by athletes themselves for its lack of usability, but has also come under attack by data-privacy experts accusing this system of breaching multiple data privacy laws.     

Mechanical and tribological properties of polymer-derived Si/C/N sub-millimetre thick miniaturized components fabricated by direct casting

The utilization of silicon-based polymers as a source of amorphous non-oxide ceramics obtained upon pyrolytic treatment of them is increasingly gaining attention in research and is currently expanding into the field of commercial products. This work is focused on the near-net shaped fabrication, mechanical and tribological properties of a polymer-derived Si/C/N system.Small sub-millimetre thick ceramic test discs and bars were fabricated by casting of polysilazane and/or polycarbosilane precursor mixtures into elastomeric polydimethylsiloxane forms, thermal cross-linking and subsequent pyrolysis. Additional carbon was introduced on the molecular level using triphenylvinylsilane as the precursor, its cross-linking with the polymers via hydrosilylation prohibits phase separation of graphite within the amorphous matrix. The characteristic strength of nearly 700 MPa along with stable low friction coefficients in sliding against similar polymer-derived ceramics testifies to their potential in micro electro mechanical system applications.     

Confirmation bias in sequential information search after preliminary decisions: An expansion of dissonance theoretical research on selective exposure to information.

Research on selective exposure to information consistently shows that after having made a decision, people prefer supporting over conflicting information. However, in all of these experiments participants were given an overview of all available pieces of information, selected them simultaneously, and did not process the requested information during the selection phase. In the present research the authors show that an even stronger preference for supporting information arises if information is presented and processed sequentially instead of simultaneously (Experiment 1), and they demonstrate that this stronger confirmation bias is due to sequential presentation and not to sequential processing of information (Experiment 2). The authors provide evidence that the increase in confirmation bias under sequential presentation is caused by heightened commitment due to the participants' increased focusing on their decision (Experiments 3 and 4). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A novel multiobjective optimization algorithm based on bacterial chemotaxis

In this article a novel algorithm based on the chemotaxis process of Echerichia coli is developed to solve multiobjective optimization problems. The algorithm uses fast nondominated sorting procedure, communication between the colony members and a simple chemotactical strategy to change the bacterial positions in order to explore the search space to find several optimal solutions. The proposed algorithm is validated using 11 benchmark problems and implementing three different performance measures to compare its performance with the NSGA-II genetic algorithm and with the particle swarm-based algorithm NSPSO.     

Treating missing values in INAR(1) models: An application to syndromic surveillance data

Time-series models for count data have found increased interest in recent years. The existing literature refers to the case of data that have been fully observed. In this article, methods for estimating the parameters of the first-order integer-valued autoregressive model in the presence of missing data are proposed. The first method maximizes a conditional likelihood constructed via the observed data based on the k -step-ahead conditional distributions to account for the gaps in the data. The second approach is based on an iterative scheme where missing values are imputed so as to update the estimated parameters. The first method is useful when the predictive distributions have simple forms. We derive in full details this approach when the innovations are assumed to follow a finite mixture of Poisson distributions. The second method is applicable when there are no closed form expression for the conditional likelihood or they are hard to derive. The proposed methods are applied to a dataset concerning syndromic surveillance during the Athens 2004 Olympic Games.