Materials Literature
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The aim of this work is the study of the U.V. radiations effects on plasticized Poly (vinyl chloride) used as waterproofing membrane in Building and also in Public Works. The ageing fact due to U.V. radiations has been followed for 3.000 hours, checking the changes produced in the composition of the material, on its m…
This work, which follows on from previous ones, studies the development of the solid-stage quantity formed in ASTM D 1141-75 artificial sea-water, in which the series of samples of mortar (1:3), made up of a portland cement resistant to sulfate (cement 2 < > P 450-Y) and the mixtures: cement 2/slag = 85/15, 65/35, 40/…
This theoretical and experimental study on cement or lime and cement mortars brings up to date the contents of Chapter 3: MORTARS, of Norm MV 201-1972 "Resistant brick-work walls" which lost its validity when disappeared portland cement P-250, substituted by portland cement PA-350 with active additions, prescribed in…
In this article, the author has the purpose to give a general view of the applications of the automatic equipment of X ray diffraction purchased by the I.E.T.c.c., quoting the main software programs used by the team in its qualitative, quantitative and crystallographic analysis, as well as to give a simplified account…
Transmission zone plates composed of materials describable by the complex index of refraction n^[n^=(1-δ)+ik] modulate both the amplitude and the phase of the light passing through them. In this paper, a general variational approach to the design of zone-plate profiles that maximize system transfer functions, such as…
A previously unreported basic bismuth carbonate, (Bi0)4(0H)2C03, has been identified as an intermediate product in the interconversion of a-BiZ03 and synthetic bismutite, (BiO)?CO,, in aqueous carbonate solutions. It has a narrow stability field, between C 0 2 partial pressures of 10-55".0 Pa and IO-' .""' Pa, in the…
Even daylight effects the rearrangement of dihydroazulene 1 into 8-vinylheptafulvene 2; thermally, the reaction proceeds in the reverse direction. The behavior of 1 is largely determined by the residue R. The reaction cycle could find application in the storage of information.
A new approach is given for obtaining fast electro-optical response and good angular-viewing characteristics in a liquid-crystal variable-retardation device. The improved characteristics make the new device well suited for use in field-sequential color systems.
In heterogeneous materials such as concretes or rocks, failure occurs by progressive distributed damage during which the material exhibits strain‐softening, i.e., a gradual decline of stress at increasing strain. It is shown that strain‐softening which is stable within finite‐size regions and leads to a nonzero energy…
Neutron inelastic scattering experiments have been carried out to measure the phonon energies of deuterated naphthalene C 10 D 8 for the lowest 12 dispersion branches along ( xi 00) and (00 xi ) directions at various temperatures ranging from 6 to 300K. Using measured mode Gruneisen parameters the quasiharmonic shifts…
The form of the collision integral describing elastic scattering of electrons and phonons by crystal defects is discussed once again. It is shown that in the absence of detailed balance for the transition probability (Wkk' ≠ Wk'k), the collision integral does not contain Fermi or Bose factors (1nk) contrary to the poi…
The present review is devoted to an analysis of the relationship between the changes in the structure and reactivity of solids, brought about by the development of a deformation. It has been shown that the principal regular features of mechanochemical transformations are determined by the extent of the structural diso…
Closed nonlinear equations are derived for a self-consistent treatment of density propagation, self-diffusion and current relaxation in a classical monatomic fluid. The solution for a hard-sphere model system brings out a phase transition to a glass at the packing fraction 0.516. Approaching the transition from the gl…
The first observation of the nematic-smectic-$A$-smectic-$C$ multicritical point in a single-component liquid-crystal system is reported. High-resolution pressure-temperature data are presented, which support the view that the phase diagram is universal near the nematic-smectic-$A$-smectic-$C$ point.
We report high-precision measurements of the shear modulus, viscosity, and specific heat of cholesteryl nonanoate through its blue phases (BPI-BPIII). For BPI and BPII we find a shear modulus which remains finite as the frequency approaches zero, indicating that they are viscoelastic solids. We find that the cholester…
We show that the dynamically selected velocity and tip radius of dendrites in the boundary-layer model of solidification have the special values which permit the existence of steady-state needle-crystal solutions. This result, in conjunction with considerations of stability, provides new insight concerning the validit…
Plastic deformation and stability are investigated of the hardened and structural states of zinc single crystals with forest dislocations in the system {1122} 〈1123〉 by shearing in the slip system (0001) [2110]. It is found that at 293 and 77 K plastic deformation in such single crystals has a pronounced jump-like nat…
On the basis of the dynamical theory a new geometry of X-ray diffraction is suggested and analyzed in detail. Diffraction scattering occurs from the planes deviated by several degrees from the surface normal, the incident and diffracted beams forming small glancing angles with the surface. It is shown that the asymmet…
Structure peculiarities and disorderness of trigonal Ca3Ga2Ge4O14 and Sr3Ga2Ge4O14 crystals are considered. Absorption and luminescence characteristics and stimulated emission parameters of Nd3+ ions in said compounds are investigated. The luminescence intensity parameters of the activator are analyzed and the cross-s…