Microstructural study of a UHPFRC incorporating ECat

Ultra-high performance fibre reinforced cementitious composites (UHPFRC) is a family of advanced cementitious materials with optimized matrix packing density, very low water/binder ratio (w/b90%) with high pozzolanic activity similar to SF. The average particle diameter of the ECat is 91.65 m and they possess a very high internal porosity with high water affinity. Previous results obtained on UHPFRC incorporating ECat showed that this material acts as an internal curing agent reducing the autogenous shrinkage. This research focuses on the microstructural behaviour of a recently developed UHPFRC incorporating ECat. For this purpose, to quantitatively estimate the influence of ECat particles on the amount of hydration products, thermogravimetric analysis (TGA) was performed on specimens at different ages. Similarly, the influence of ECat particles on the pore structure of the newly developed mixture is also assessed by performing mercury intrusion porosimetry (MIP). The relation between the hydration products and the pore structure is analyzed

Usability in virtual and augmented environments: A qualitative and quantitative study

Virtual and Augmented Reality are developing rapidly: there is a multitude of environments and experiments in several laboratories using from simple HMD (Head-Mounted Display) visualization to more complex and expensive 6-wall projection CAVEs, and other systems. Still, there is not yet a clear emerging technology in this area, nor commercial applications based on such a technology are used in large scale. In addition to the fact that this is a relatively recent technology, there is little work to validate the utility and usability of Virtual and Augmented Reality environments when compared with the traditional desktop set-up. However, usability evaluation is crucial in order to design better systems that respond to the users’ needs, as well as for identifying applications that might really gain from the use of such technologies. This paper presents a preliminary usability evaluation of a low-cost Virtual and Augmented Reality environment under development at the University of Aveiro, Portugal. The objective is to assess the difference between a traditional desktop set-up and a Virtual/Augmented Reality system based on a stereo HMD. Two different studies were performed: the first one was qualitative and some feedback was obtained from domain experts who used an Augmented Reality set-up as well as a desktop in different data visualization scenarios. The second study consisted in a controlled experiment meant to compare users’ performances in a gaming scenario in a Virtual Reality environment and a desktop. The overall conclusion is that these technologies still have to overcome some hardware problems. However, for short periods of time and specific applications, Virtual and Augmented Reality seems to be a valid alternative since HMD interaction is intuitive and natural.Electrical Engineering, Mathematics and Computer Scienc

Demographic and clinical data in acquired hemophilia A: results from the European Acquired Haemophilia Registry (EACH2).

Background: Acquired hemophilia A (AHA) is a rare autoimmune disease caused by autoantibodies against coagulation factor VIII and characterized by spontaneous hemorrhage in patients with no previous family or personal history of bleeding. Although data on several AHA cohorts have been collected, limited information is available on the optimal management of AHA. Objectives: The European Acquired Hemophilia Registry (EACH2) was established to generate a prospective, large-scale, pan-European database on demographics, diagnosis, underlying disorders, bleeding characteristics, treatment and outcome of AHA patients. Results: Five hundred and one (266 male, 235 female) patients from 117 centers and 13 European countries were included in the registry between 2003 and 2008. In 467 cases, hemostasis investigations and AHA diagnosis were triggered by a bleeding event. At diagnosis, patients were a median of 73.9years. AHA was idiopathic in 51.9%; malignancy or autoimmune diseases were associated with 11.8% and 11.6% of cases. Fifty-seven per cent of the non-pregnancy-related cases were male. Four hundred and seventy-four bleeding episodes were reported at presentation, and hemostatic therapy initiated in 70.5% of patients. Delayed diagnosis significantly impacted treatment initiation in 33.5%. Four hundred and seventy-seven patients underwent immunosuppression, and 72.6% achieved complete remission. Conclusions: Representing the largest collection of consecutive AHA cases to date, EACH2 facilitates the analysis of a variety of open questions in AHA