Materials Literature
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We have carried out a series of accelerated artificial ageing tests to study the evolution of the silico-organic treatment products applied to calcareous materials of the Catedral of Oviedo. Test valoration has been made both by visual examination and weight loss measuring. We conclude by comparing different behaviour…
Laboratory testing to produce intergranular stress corrosion cracking (IGSCC) of Alloy 600 steam generator tubing in primary water environments can require lengthy exposure times, even at a temperature of 360 C (680 F). Recent testing of Alloy 600 in hydrogen-containing steam at 400 C (750 F) has shown the characteris…
The purpose of this work is to make the coupled cluster (CC) energy stationary with respect to molecular-orbital (MO) variations in the reference configuration. To achieve this, we have used the Z vector, the solution of a set of perturbation-independent CPHF-like equations, to rotate the MOs. A new energy and gradien…
Abstract A cation-exchange capacity (CEC) method based on ion-sieving properties was developed for the quantitative determination of clinoptilolite in soils. In this method, both zeolitic and non-zeolitic exchange sites in the soil sample are saturated with Na + . The CEC of the non-zeolitic exchange sites is determin…
To determine molecular architecture of the type IV collagen network in situ, the human amniotic basement membrane has been studied en face in stereo relief by high resolution unidirectional metal shadow casting aided by antibody decoration and morphometry. The appearance of the intact basement membrane is that of a th…
Abstract Experimental data on gas sorption and polymer swelling in glassy polymer—gas systems at elevated pressures are presented for CO 2 with polycarbonate, poly(methyl methacrylate), and polystyrene over a range of temperatures from 33 to 65°C and pressures up to 100 atm. The swelling and sorption behavior were fou…
Fibrin deposition is a consistent early event in solid tumors and healing wounds and precedes new blood vessel ingrowth in both. We now demonstrate that fibrin gels of themselves induce an angiogenic response in the absence of tumor cells or platelets. Angiogenesis was enhanced when certain chemoattractants or mitogen…
Abstract Dynamic mechanical measurements allow direct determination of the instant at which a network polymer gels. In such an experiment, the evolution of G ′( t ,ω 0 ) and G ″ ( t ,ω 0 ) is measured in small amplitude oscillatory shear as a function of cross‐linking time t . The frequency ω 0 is kept constant throug…
This review covers a wide range of experimental and theoretical studies of two-level or tunnelling states in glasses. Emphasis is on fundamental physics rather than a detailed comparison of experiment and theory. Sections cover the static and dynamic properties of tunnelling states, their contribution to thermal prope…
The weight of a phase in a mixture is proportional to the product of the scale factor, as derived in a multi-component Rietveld analysis of the powder diffraction pattern, with the mass and volume of the unit cell. If all phases are identified and crystalline, the weight fraction W of phase p is given by W_{p} = S_{p}…
The temperature-dependent structure of crystalline methylammoniumtrihalogenoplumbates (II)—CH3NH+3PbX−3 (X=Cl, Br, I)—as determined by x-ray diffraction, is compared with measurements of the temperature-dependent complex permittivity at frequencies of 50–150 GHz. The dielectric measurements reveal a picosecond relaxat…
Structure, thermodynamics, and electronic properties are predicted for a new low energy phase of carbon which contains planar sheets equally occupied by sp2 and sp carbon atoms. The isolated planar sheets have the same planar symmetry as do the layers in graphite (p6m) and can be formally viewed as resulting from the…
This article attempts to review a number of macroscopic measurements which have been used to explore the electrical, mechanical, thermal, and optical characteristics of relaxor ferroelectrics and to authenticate the compositional heterogeneity model which was first proposed by G.A. Smolenskii to describe these materia…
The dipole moment-covalency-polarisability correlation ligand-field model is proposed, after a number of experimental spectra data have been analysed. In this model, once the mu - kappa - alpha correlations are established, there is no need to introduce the fitting parameters in order to investigate the optical and ma…
Thermal properties of semiconductor superlattices have been investigated for the first time. The thermal properties of AlAs/GaAs superlattices were measured with the ac calorimetric method. It is found that the thermal diffusivity and thermal conductivity of the AlAs/GaAs superlattices are larger than those of the AlG…
The core structure of half-integer wedge disclinations in nematic liquid crystals has been investigated within the Landau-de Gennes theory, by solution of the appropriate Euler-Lagrange equations. Close to the nematic-isotropic transition the energy density exhibits a domain-wall-like structure around the core which d…
Formation of the equilibrium intermetallic compound NiZr in sputter deposited Ni/Zr diffusion couples is suppressed by the formation of a metastable amorphous NiZr alloy until a critical thickness of the amorphous NiZr interlayer is reached. The temperature dependence of this critical thickness is studied experimental…
A simple method is proposed to calculate total energies of solids with lattice defects. Lattice-defect energies are determined via perturbation theory on a crystal whose lattice constant is chosen optimally. The method is applied to the computation of surface energies of a series of transition metals as a function of…
The electronic structure of five antimony chalcogenides, Sb${\mathrm{I}}_{3}$, ${\mathrm{Sb}}_{2}$${\mathrm{Te}}_{3}$, SbTeI, TlSb${\mathrm{S}}_{2}$, and ${\mathrm{Tl}}_{3}$Sb${\mathrm{S}}_{3}$, is investigated. Information from x-ray diffraction, M\"ossbauer spectroscopy, electrical measurements, and photoemission sp…
Molecular, hydrodynamic, and thermodynamic properties of nylon 11 in meta cresol and 1,1,1,2,2,2-hexafluor-2-propanol (HFIP) solutions, as well as its distribution of molecular weights were investigated by means of viscosimetry, conductimetric titration of end groups, light scattering, and fractionation by successive…