657 research outputs found
Thermodynamic properties of interstitial elements in the refractory metals Semiannual report, 1 Jun. - 1 Dec. 1966
Thermodynamic properties of interstitial elements in refractory metal
Thermodynamic properties of interstitial elements in the refractory metals Semiannual report, 1 Dec. 1968 - 31 May 1969
Carbon activity in refractory metal
Thermodynamics and kinetics of reactions in protective coating systems
A study of the aluminization of Ni from packs containing various percentages of unalloyed Al confirmed that the surface aluminum content of specimens aluminized tends to decrease with time and consequently a simple parabolic law for the weight-gain vs. time relationship is not obeyed. The diffusivity-composition relationship in NiAl was examined, and a set of curves is presented. A numerical method for the calculation of coating dissolution rates was developed and applied to NiAl-Ni3Al type of coatings
System testing of a production Ada (trademark) project: The GRODY study
The use of the Ada language and design methodologies that utilize its features has a strong impact on all phases of the software development project lifecycle. At the National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC), the Software Engineering Laboratory (SEL) conducted an experiment in parallel development of two flight dynamics systems in FORTRAN and Ada. The teams found some qualitative differences between the system test phases of the two projects. Although planning for system testing and conducting of tests were not generally affected by the use of Ada, the solving of problems found in system testing was generally facilitated by Ada constructs and design methodology. Most problems found in system testing were not due to difficulty with the language or methodology but to lack of experience with the application
Free energies of formation of WC and WzC and the thermodynamic properties of carbon in solid tungsten
The activity of carbon in the two-phase regions - W + WC and W + W2C was obtained from the carbon content of iron rods equilibrated with mixtures of metal plus carbide powders. From this activity data the standard free energies of formation of WC and W2C were calculated. The temperature of the invariant reaction W2C = W + WC was fixed at 1570 + or - 5K. Using available solubility data for C in solid W, the partial molar free energy of C in the dilute solid solution was also calculated. The heat of solution of C in W, and the excess entropy for the interstitial solid solution, were computed, assuming that the carbon atoms reside in the octahedral interstices of bcc W
Thermodynamic properties of interstitial elements in the refractory metals Semiannual report, 1 Dec. 1967 - 31 May 1968
Thermodynamic behavior of interstitial elements in Mo, W, Nb, and T
Thermodynamic properties of interstitial elements in the refractory metals Progress report, 1 Jun. - 30 Nov. 1969
Thermodynamic properties of carbon in molybdenum and tungsten at solubility limi
On the kinetics of pack aluminization
A theory of pack aluminization has been formulated by combining gaseous and solid-state diffusion rates. This theory relates the surface composition of the coating and therefore, in principle, the phase morphology and the growth rate of the coating, to pack operating parameters such as pack aluminum density, type of activator, temperature and others. Experimental data on the aluminization of unalloyed nickel in pure aluminum packs obtained to date are in good agreement with the predictions of the theory
First record of three species of "Pythium" from Moroccan waters
First record of three species of Pythium from Moroccan waters. Species of Pythium, including P.torulosum, P.catenulatum and P. "Group F", isolated from dam near Rabat city (capital of Morocco) in northern Africa, are described. Taxonomic and morphological details of the fungi are discussed. This work is the first report of these species from Moroccan waters.Primeras citas de tres especies de Pythium para Marruecos. Se describen especies de Pythium, incluyendo P. torulosum, P. catenulatum y P. "Group F", aislados cerca de la ciudad de Rabat (Marruecos) en el norte de Africa. Se discuten detalles taxonómicos y morfológicos del hongo. Este trabajo es la primera refencia de estas especies en aguas de Marruecos
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