The kinetics of hydrogen diffusion in diopside single crystals have been investigated through dehydration experiments performed in air between 700 ø and 1000øC. Samples oriented along [001], [100]*, and [010] crystallographic directions were cut in thin slices of less than 1 mm thickness and about 4 x 4 mm 2 across. The decrease, with time of heating, of the OHconcentration was measured from the integral of the OH-absorption bands of infrared spectra taken on a few millimeter per millimeter area at the center of the sample slices. The data show no significant effect of crystallographic orientation on the rates of dehydration, suggesting that hydrogen diffusion in diopside is isotropic. The simultaneous fit of diffusion data measured in the three directions to an Arrhenius law follows: In D = In DO -exp[-136 + 27 kJ/mol/RT] with In DO = -14.5 + 2.8. The rates of dehydration of diopside are slower than the rates of dehydration of olivine. However, if olivine undergoes extensive dehydration during ascent within magma, dehyß ..,•,o.. of a;,,,o;a• may also be •ig-it'ic•nt if we. ta__ke into account the smaller •m'ain size of this mineral, as observed in nodules.

Interoperability testing and analysis tools provide a means for achieving and assuring the integrity of multivendor intelligent electronic devices (IEDs) data exchanges. However, the testing and analysis are very time consuming and error prone, and these problems worsen when a substation becomes large and complex during the engineering process, commission, replacement, maintenance, and extension. To address this challenge, this paper presents a virtual digital substation test system (VDSTS) with interoperability analysis tools for assessing and identifying the engineering challenges for the multiple-vendors digital substation. This VDSTS consists of three parts: (i) A virtual digital substation modelling for generating real-time digital substation primary plant operation and fault conditions, (ii) a standard IEC 61850-based substation protection, automation, and control (PAC) system architecture with multivendor IEDs and bay solutions, and (iii) multivendor Substation Configuration description Language (SCL) tools and in-house built data visualisation tool. The study focuses on the interoperability testing of sampled values (SV), generic object-oriented substation events (GOOSE), and manufacturing message specification (MMS) communication services, as defined in IEC 61850. The main issues identified are compatibility issues of SCL tools, protocol implementation issues, different information models, and application limitations. The outcomes will help utilities to reduce the risks associated with the general rollout of digital substations.

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