Fully submerged composite cryogenic testing

New methods for marine salvage and decommissioning of structures in the open sea are continually being sought in order to improve control and lower operational costs [1]. The concept design of a lightweight, cryogenic, marine, heavy lift, buoyancy system has been investigated [2]. The objective is to be able to raise or lower high mass objects controlled solely from a surface support vessel. The overall design concept and associated system development issues have been discussed previously. A number of the sub-systems in one complete buoyancy system involve considerable design and development, these include: structural design of the buoyancy chamber, mechanical systems to control and connection to the lift device, the cryogenic system itself and overall process control systems. The main area of concern in the design process is the composite cryogenic Dewar. This is required to operate not only at temperatures as low as -196oC but also to withstand pressure differences exceeding 35bar. As such the composite materials have to perform in a very aggressive environment. This work details a method for fully submersed composite cryogenic testing in order to qualify the materials for use in the Dewar of the buoyancy system

VOWL 2: User-Oriented Visualization of Ontologies

Abstract. Ontologies become increasingly important as a means to structure and organize information. This requires methods and tools that enable not only ontol-ogy experts but also other user groups to work with ontologies and related data. We have developed VOWL, a comprehensive and well-specified visual language for the user-oriented representation of ontologies, and conducted a comparative study on an initial version of VOWL. Based upon results from that study, as well as an extensive review of other ontology visualizations, we have reworked many parts of VOWL. In this paper, we present the new version VOWL 2 and describe how the initial definitions were used to systematically redefine the visual notation. Besides the novelties of the visual language, which is based on a well-defined set of graphical primitives and an abstract color scheme, we briefly describe two im-plementations of VOWL 2. To gather some insight into the user experience with the new version of VOWL, we have conducted a qualitative user study. We report on the study and its results, which confirmed that not only the general ideas of VOWL but also most of our enhancements for VOWL 2 can be well understood by casual ontology users

The thermal conductivity of perlite insulation under varying conditions of temperature, humidity and packing density

Measurements have been made of the thermal conductivity of expanded perlite under varying conditions of density and humidity over the temperature range 113 K to 298 K. A thermal conductivity test cell was constructed according to the requirements of ASTM C177. The measurement system and test methods are described. The new test data shows that perlite conditioned in standard conditions has a thermal conductivity of 0.0153 to 0.0193 W/mK at 113 K. Varying the relative humidity (R.H) of the environmental chamber used to prepare some samples from 40% to 80%, made little to no change to the thermal conductivity values. However, increasing the density of the perlite packed into the cavity of test cell, by 15% to 25% resulted in moderate increases in the thermal conductivity at the maximum density of 2.0% and 7.7% and was dependent on the source