Worldwide concern in scientific, industrial, and governmental com munities over traces of toxic chemicals in foodstuffs and in both abiotic and biotic environments has justified the present triumvirate of specialized publications in this field: comprehensive reviews, rapidly published progress reports, and archival documentations. These three publications are integrated and scheduled to provide in international communication the coherency essential for nonduplicative and current progress in a field as dynamic and complex as environmental contamination and toxicology. Until now there has been no journal or other publication series reserved exclusively for the diversified literature on "toxic" chemicals in our foods, our feeds, our geographical surroundings, our domestic animals, our wild life, and ourselves. Around the world immense efforts and many talents have been mobilized to technical and other evaluations of natures, locales, magnitudes, fates, and toxicology of the persisting residues of these chemicals loosed upon the world. Among the sequelae of this broad new emphasis has been an inescapable need for an articulated set of authorita tive publications where one could expect to find the latest important world literature produced by this emerging area of science together with documentation of pertinent ancillary legislation."

Tension-tension fatigue behavior of a prototype Silicon Carbide/Silicon Carbide (SiC/SiC) ceramic matrix composite (CMC) material was investigated at 1000 C in laboratory air and in steam environments. The material consists of a SiC matrix reinforced with CG NICALON fibers woven in an eight harness satin weave (8HSW) and coated with a BN/SiC dual-layer interphase. The composite was manufactured by a Polymer Infiltration and Pyrolysis (PIP) process. A seal coat of SiC and elemental boron was applied to the test specimens after machining. The tensile stress-strain behavior was investigated and the tensile properties were measured at 1000 C. Tension-tension fatigue behavior was studied for fatigue stresses ranging from 60 to 100 MPa. The fatigue limit (based on a run-out condition of 2 x 10 cycles) was 80 MPa, which is 59% of the Ultimate Tensile Strength (UTS). The material retained 82% of its tensile strength. The presence of steam significantly degraded the fatigue performance at 1000 C. In steam the fatigue limit dropped below 60 MPa (44% UTS). Microstructural analysis revealed severe oxidation occurring in the specimens tested in steam, which resulted in accelerated damage development and failure. Through quantitative and qualitative analysis, the damage and premature failure of the composite in the steam environment is believed to be due to oxidation embrittlement. This material also showed considerably worse performance than similar SiC/SiC composites with a great deal of variability between specimens cut from different panels. The possibility exists that inadequate process control may be behind the degraded performance of the material and the panel-to-panel variability in performance.