The control of tritium in ETHEL

The operation of the European Tritium Handling Experimental Laboratory (ETHEL) will require the implementation of means and procedures for allowing tritium control within the facility. For that purpose, account must be taken of the particular characteristics of tritium, such as its high mobility, capacity to dissolve in materials, often limited precision when performing inventory measurements. This paper estimates the influence of these effects on the overall tritium balance in ETHEL. By employing available models for predicting tritium hold-up, it is estimated that three to four grams of tritium may potentially remain irreversibly fixed in various plant items of the standard laboratory infrastructure (exclusive of experimental circuits). On the other hand, the highest overall precision that may be attained with the present plant regarding inventory measurements is estimated to be of the order of few percent. On the basis of the above estimates, the allowable limits for the Material Unaccounted For (MUF) are discussed.     

Investigation of calcium zirconate ceramic synthesized by slip casting and calcination

In order to provide large scale bodies composed of synthesized calcium zirconate ceramic, the slip casting technology as well as calcination was applied. Optimized suspensions with high solid content and low viscosity were obtained by adding a dispersant agent and subsequently slip cast into plaster moulds to produce bars. Densification as well as material properties were studied at temperatures ranging from 1200 to 1500 °C. Due to their good properties, bars sintered at 1500 °C were selected for crushing to get coarse and fine grains for calcium zirconate rich refractory materials. To evaluate the applicability of the slip casting route, the mechanical properties of the obtained coarse grains were compared with commercial fused-cast product.     

Fused calcium zirconate for refractory applications

This article investigates dense CaZrO₃ produced by electric arc melting and compares it to solid state synthesized CaZrO₃. The fused CaZrO₃ had a considerable lower porosity than the solid state synthesized material, however due to evaporation of some CaO during the electric arc melting the stoichiometric ratio of CaO/ZrO₂ was slightly smaller than one, resulting in the formation of cubic ZrO₂ as a second phase. To determine the local phase distribution the materials were investigated with EBSD in addition to integral XRD. The vibration polishing of the ceramics resulted in excellent EBSD patterns. Die pressed cylinders of the fused material led to a porosity as low as 14.3%. The linear thermal expansion coefficient from 25 °C to 1000 °C was 10.45 × 10^?6 K^?1. The cold isostatic pressing of larger crucibles resulted in higher porosity of 15.9–16.5%. The EBSD analysis and the cold isostatic pressed crucibles can be applied in corrosion tests for titanium melts.     

Cognitive match as a predictor of psychotherapy outcome.

63 cognitively matched or unmatched patient–therapist pairs were followed in a double-blind methodology utilizing the Interpersonal Discrimination Test (IDT) as a measure of cognitive match between each pair. Premature termination occurred for 60% of the unmatched pairs and for 24% of the matched pairs. The Global Assessment Scale indicated a significantly faster rate of improvement for the remaining matched pairs at the 12-wk mark. Unmatched pairs eventually reached similar endpoints with final termination outcome measures being unable to distinguish between the 2 groups. Findings demonstrate the ability of the cognitive-match methodology, and specifically the ability of the IDT, to predict higher rates of early and dissatisfied terminations when patients and therapists are unmatched in cognitive structure. Findings confirm an earlier finding by J. E. Carr (1970) of greater improvement after 12 wks of treatment for matched vs mismatched patient–therapist pairs. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Performance improvement of Distributed Virtual Environments by exploiting objects’ attributes

Distributed virtual environments need to address issues related to the control of network traffic, resource management, and scalability. Given the distributed nature of these environments, the main problems they need to overcome are the efficient distribution of workload among the servers and the minimization of the communication cost. In this direction, a lot of work has been done and numerous relevant techniques and algorithms have been proposed. The majority of these approaches mainly focus on user entities and their interactions. However, most of actual DVE systems include additional and non-dynamic elements, denoted as objects, whose presence can affect users?? behavior. This paper introduces virtual objects?? attributes and proposes two approaches that exploit these attributes in order to handle workload assignment and communication cost in DVE systems. Both approaches take into account scenario-specific aspects of DVE systems, such as the impact that entities?? attributes have on each other and the way this impact can affect the system??s state. These scenario-specific aspects are then combined with quantitative factors of the system, such as workload, communication cost, and utilization. The experiments conducted in order to validate the behavior of the proposed approach show that the incorporation of object??s presence can improve the DVE system??s performance. More specifically, objects?? presence and their attributes can assist in the significant reduction in the communication cost along with effective workload distribution among the system??s servers.     

STEPS: Supporting Traditional Education Procedures—A TCP/IP Multimedia Networks-Based Model

This paper describes an integrated model for the realization of an Open and Distance Learning (ODL) environment supporting traditional learning procedures, through collaborative learning and active participation of the involved group of students. Internet technologies are used as a vehicle for distribution of interactive multimedia at the user's desktop. We also present off-the-shelf solutions for the architecture and implementation of an Educational Network necessary to support the ODL environment. An Educational Entity (specially shaped part of a legal educational authority) is also prescribed as the central point for the Educational Network, being the content provider and the learning procedure evaluator. It is mainly intended to be used in a higher education setting, aspiring to be an efficient solution for the common educational needs of a group of students and teachers or researchers.