Detonation-Sprayed Coatings of (Ti,Cr)B2–NiAlCr Composite Materials II. Mechanical and Tribotechnical Properties

Powder Metallurgy and Metal Ceramics - The mechanical and tribotechnical properties of detonation-sprayed coatings produced from (Ti, Cr)B2–NiAlCr composites were studied. The influence of...     

Surface preparation for the application of hardening protective coatings

Conclusion Quantitative monitoring of the energy state of the treated surface made it possible to select the optimal treatment regime using SPD; this ensured an increase in the growth rate of the organometallic coating being applied and its adhesive strength.Moscow Automobile Traffic and Highway Construction Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 2–4, December, 1993.     

Effect of additives on the properties of silicon carbide-based refractories obtained by self-propagating high-temperature synthesis (SHS)

The effect of refractory additives (alumina, alumosilicate mortar, and zircon concentrate) on the properties of SHS refractories based on silicon carbide is studied. It is shown that introduction of the additives favors enhancement of the compressive strength of the material. The enhancement is especially efficient in the case of an admixture of zircon concentrate. The resistance of the silicon carbide material to corrosion in slags of titanium production and iron foundry production is improved when the content of the additives is increased from 5 to 30%. The addition of zircon concentrate allows the slag-resistance of the silicon carbide material to be increased by a factor of 6, while the effect of alumina and alumosilicate mortar is less pronounced. Translated from Ogneupory i Tekhnicheskaya Keramika, No. 1, pp. 17–18, January, 1997.     

Reliability of skin biopsy pathology

BACKGROUND: The diagnosis of skin disease by histologic examination is regarded as the reference standard upon which therapy and follow-up are determined. Our study investigated the reliability of skin biopsy diagnosis requested by family physicians and physicians' assistants. METHODS: Biopsy diagnoses by a community-based pathology group were reinterpreted by our study dermatopathologist on a sample of 119 skin biopsies randomly selected from the 1844 biopsies performed by family physicians and physicians' assistants at a large Washington State health maintenance organization during a 4 1/2-year period. RESULTS: There were 107 exact matches and 3 mismatches of premalignant lesions and 6 mismatches of benign diagnoses. In addition, two melanomas diagnosed by the community-based pathologists were interpreted as benign by our study dermatopathologist. A third melanoma diagnosed by the community-based group was interpreted as a poorly differentiated squamous cell cancer by the university dermatopathologist. The weighted kappa, 0.83, indicated excellent interrater agreement. CONCLUSION: Although our study showed excellent interrater concordance of skin biopsy interpretation, there was disagreement about three melanomas between a community-based general pathology group and our study dermatopathologist. The melanoma disagreement is consistent with previous studies that found poor interrater agreement for early melanomas. The community-based pathologists were uncertain about two of these melanomas, and as part of their quality control and review procedures requested confirmation by an expert pathologist, who agreed with the melanoma diagnosis. Family physicians are justified in requesting a second opinion (if not automatically requested by a community laboratory) when the histopathologic diagnosis is not in concordance with the clinical history or impression or when the pathologist is unsure of the diagnosis.     

Ultrapurification of archaeological lead

Based on purification efficiency calculations for lead distillation, we developed a combined process for the ultrapurification of archaeological lead. We obtained pilot amounts of high-purity archaeological lead and PbO with the following contents of detrimental impurities: U, <2 ppb; Th, <1 ppb; Ni, Cu, Fe, Si, Ti, Mg, Al, Mn, Cr, V, Co, < 0.1 ppm; K, Ca, Zn, Cd, Ag, Sb, < 1 ppm. Lead of such purity can be used in low-background experiments as a protective shield material and in the growth of low-background PbWO₄ and PbMoO₄ scintillator crystals. From an isotope ratio, we were able to identify the origin of the archaeological lead.