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An account to the mineralogy of Re-bearing phases

100%

Krzyżak R.

tom R. 49, nr 8

398-399

The up-to-date mineralogy of Re is somewhat different from that frequently presented in the world-wide-known literature, and namely the contemporary formula of dzhezkazganite is ReMoCu2PbS6. Besides, native Re, a Re amount of Cu-Mo-S-, Cu-Mo-As-S-, crichtonite-senaite mineral groups and anhydrite is well konown. A Re-bearing galena-like phase, with Re amount of about 3,0 wt. %, was encountered in Hovin, Telemark, Norway. This phase mainly occurs with bornite, galena and chalcopyrite, being a part of this metamorphosed assemblage. The pre-metamorphic assemblage must have been 'saturated' with Re (high isomorphic capacity).

Aktualna mineralogia minerałów renu jest nieco odmienna od często prezentowanej w znanej literaturze. Wzór dżezkazganitu brzmi obecnie ReMoCu2PbS6. Dobrze znane jest ponadto występowanie renu rodzimego oraz to, iż takie grupy mineralne jak Cu-Mo-S, Cu-Mo-As-S, krichtonitu-senaitu czy też anhydryt zawierają Re. W złożu Hovin (Telemerk, Norwegia) znaleziono galenopodobny minerał z zawartością Re około 3,0% wagowo. Minerał ten jest częścią zmetamorfizowanego zespołu minerałów wraz z boronitem, galeną i chalkopirytem. Pojemność izomorficzna tego zespołu minerałów ze względu na Re przed metamorfizmem musiała być duża.

A thermomechanical aspect of the ceramic-capped piston of hypothetical adiabatic diesel engine

63%

Jaskólski J. , Krzyżak R.

tom Vol. 13, No. 2

169-177

The paper concerns a hypothetical Al.-alloy piston coated (capped) first by labradore and then capped by YSZ. The labradore, a member of the feldspar group is deemed thermal-shock resistant, the YSZ(PSZ) can be shock-resistant, but the outcome of the two with the Al.-alloy is not known. The analysis were made in two ways by ANSYS 10.0, as wholly isotropic materials and (second) labradore treated as wholly orthotropic one as basing on a designed texture. The above programme was fed up by the FORTRAN95-outcome of temperatures and the other B.C.’s.The temperatures between the ceramics and the alloy (except one node!!, the FORTRAN) are ( from the above two procedures), 222.63 to 270-300 graduate C, at the first groove are about 290 graduate C, and, surely lower (orthotropic). The relatively low (to ceramic) inner tensile stresses are embraced by the compressive ones from all the sides. The only problem is the-alloy bearing capacity at some sections at the ceramic boundary (and only there). But, it was the aim of the work to stick ceramics there.The dangerous stresses can occur at the pin .The ‘orthotropic ‘ results are better than the ‘iso’-ones and more true.. Taking into account that the real loading will be lower (porosity of the ceramics, the mass and the possible subtraction of stresses, i.e. those ceramic-production-confined ones) , the laboratory production of the piston appears worth.

The temperature - and stress fields of valves of IC engine

63%

Jaskólski J. , Krzyżak R.

tom Vol. 14, No. 3

245-252

The paper concerns building up one exhaust valve of composite-steel and two intake ceramics-steel valves of a hypothetical adiabatic engine. The input temperatures were computed using three diverse FORTRAN95 programs, solving a shortened optical integral equation with radiative transfer, transient differential equation while starting and switching off the engine and a rod like diff. Equation with 'progonka' (Thomas) solution. The ANSYS11 programme was fed up with the output of the programs. It turns out that, generally, a mineralogical, crystal-chemical approach to the joining of materials results in stresses known from the common metal engines. Such problems as CTE enhancing (partly hypothetical) by means of doping the anionic compounds by cationic ones, swelling of structures, compressibility versus coefficient of thermal expansion (CTE) , compatibility of crystal motifs while joining, thermal shock resistance, switching the bonds, mechanical longevity, radiation protection etc were addressed. It turns out that true nature of the temperature and stress field, especially of the exhaust valve is closer to the FORTRAN temperature computation than, e.g. From the heat film coefficients (ANSYS11).