Macroscopic thermal dilatation coefficients as well those of the lattice have been precisely measured along principal crystallographic directions magnesium single crystals in temperature range between room and 650\ifmmode^\circ\else\textdegree\fi{}C. The vacancy concentration was thus obtained a function it reached value 72\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}5}$ neighborhood melting point. An appreciable anisotropy atom rearrangement appears during defect-formation...

The ability of orange peels (OP) and almond (AP) as adsorbents for the removal a dyestuff, namely methylene blue (MB) from aqueous solutions has been studied.After their characterization by different techniques (elemental analysis, biochemical IR spectroscopy, thermogravimetric scanning electron microscopy, mercury porosimetry), adsorption kinetics dye have investigated using common kinetic models cited in literature: first order pseudo-second order.The correlation coefficient showed that...

By means of the diffusion broadening Mossbauer resonance and a new technique positron lifetime measurements, point defects in vanadium refractory metal have been investigated up to melting point. Values formation migration enthalpies entropies obtained for both monovacancies divacancies: H1VF=(2.2+or-0.4) eV, H2VF=(3.7+or-0.8) S1VF=(4.8+or-1.4)kB, S2VF=(11.0+or-1.4)kB, H1VM=(1.2+or-0.3) H2VM=(0.8+or-0.3) eV.

Ag/Ni superlattices have been prepared by triode dc sputtering on glass substrates at 100 K. X-ray diffractometry with the scattering vector perpendicular to superlattice plane suggests structural coherence and interface sharpness whatever thickness of elemental layers. All samples present (111) textures for both Ag Ni. Magnetic measurements performed a superconducting quantum interference device magnetometer indicate in-plane anisotropy magnetization oscillatory interlayer magnetic...

Cellulose was modified under mild conditions in order to increase its capability trap pollutants.Nicotinoyl chloride hydrochloride (NCHC), with pyridine ring able adsorb cations, grafted on the substrate.This grafting has been monitored by infrared spectroscopy and elemental analysis.We have studied adsorption of Methylene Blue (MB) onto unmodified cellulose.It observed that increases three times retention capacity cellulose kinetics is perfectly represented a pseudo second model.The well...

Abstract Kinetic evidence in thermomechanical analysis experiments and carbon‐13 nuclear magnetic resonance spectroscopy ( 13 C NMR) indicates that the strength of a joint bonded with UF (urea–formaldehyde)/polymeric 4,4'‐diphenylmethane diisocyanate (pMDI) glue mixes is improved by coreaction methylol groups resins pMDI to form certain number methylene cross‐links. The formation these cross‐links predominant, rather than urethane bridges which still appear but are great minority. This...

A minimum of the magnetoresistance under low fields has been observed with a ${\mathrm{Co}}_{65}$${\mathrm{Fe}}_{35}$/Ag/${({\mathrm{Co}}_{65}{\mathrm{Fe}}_{35})}_{50}$${\mathrm{Gd}}_{50}$ trilayer at 4.2 and 300 K. This negative spin-valve effect is explained by scattering conduction electrons Co or Fe moments included in two different structures: polycrystalline (${\mathrm{Co}}_{65}$${\mathrm{Fe}}_{35}$) an amorphous one...

Measurement of macroscopic ($\frac{\ensuremath{\Delta}L}{{L}_{0}}$) and microscopic ($\frac{\ensuremath{\Delta}d}{{d}_{0}}$) thermal expansion has been carried out for cadmium single crystals, between room temperature the melting point. It was found that difference $\ensuremath{\delta}=\frac{\ensuremath{\Delta}L}{{L}_{0}}\ensuremath{-}\frac{\ensuremath{\Delta}d}{{d}_{0}}$, in a given crystallographic direction, is function which sample dependent. The ratio...

Small angle neutron scattering experiments have been performed on amorphous Fe 70 Cr 5 P 15 C 10 alloys. Contributions to SANS intensity due magnetic heterogeneities, surface imperfections and possible bulk atomic heterogeneities obtained using contrast variation methods (application of an external field and/or immersion the sample in a deuterated liquid). The may be as small 2% that surface, which turn is less than 5% coming from heterogeneities. Polishing procedures amplify these phenomena...

Abstract Using a classical analysis of diffusion data in combination with results obtained from positron annihilation, Mössbauer spectroscopy and N.M.R. experiments, the change slope Arrhenius curve reported to occur for vanadium has been quantitatively interpreted cases self-diffusion Mn, Fe, Co, Ni Cu impurity diffusion. It shown that three kinds 'point defects' contribute atomic transport: (i) free single vacancies whose efficiency culminates around 1200–1550°C; (ii) divacancies,...

Abstract Aged and whitened melamine–urea–formaldehyde (MUF) resins in a colloidal state were tested with parallel‐plate rheometry to determine the extent of their viscoelastic behavior. Only advanced states, so only when aggregated clusters occurred, did present clear indications responses, as illustrated by crossover elastic modulus viscous curves at lower strain percentages. These labile microstructures, which, broken applied shear, justified known thixotropic behavior these sufficiently...

A comparison of the evolution magnetoresistance and magnetic coupling in Ag/Ni superlattice system is presented as a function silver thickness, for nickel thickness kept at 8 \AA{}. This exhibits effect large 28% gives rise to an ideal 10--12 \AA{} antiferromagnetic coupling. No further clear oscillations are observed. Both position amplitude agreement with recent theoretical calculations.

We have studied the giant magnetoresistance of evaporated Co65Fe35/Ag alloys and we correlated effect with magnetization. observed a maximum 92% at 4.2 K under field 60 kOe. The room-temperature can be roughly evaluated to 35%. absolute decrease rho (0)- (H) in resistivity plotted versus square magnetization shows clearly two regimes: low fields, it presents linear variation independent temperature; high fields (M/Ms>0.7), deviates from an increasing slope. This behaviour is discussed...

The reentrant-spin-glass behavior for members of the amorphous (${\mathrm{Fe}}_{\mathit{x}}$${\mathrm{Cr}}_{1\mathit{\ensuremath{-}}\mathit{x}}$${)}_{75}$${\mathrm{P}}_{15}$${\mathrm{C}}_{10}$ and crystalline ${\mathrm{Fe}}_{\mathrm{x}}$${\mathrm{Cr}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$ systems are found to be similar when ${T}_{C}$'s same. This suggests some relationship between width exchange distribution average exchange. We have constructed a phase diagram these by combining...

Using magnetoresistance measurements at 4.2 K, the magnetic transitions of Fe/Gd multilayers have been studied. At low field and temperature, this system is in an aligned state where all Gd spins (or Fe spins) are direction antiparallel to because antiferromagnetic coupling spins. We show that a phase transition from Gd-aligned twisted surface-induced transititon which occurs when outermost layer iron. This surface effect extends relatively far sample (several thousands angstroms). These...

Low-field magnetization in parallel and perpendicular geometries, M\"ossbauer spectroscopy, small-angle neutron scattering data, carried out on the same samples of amorphous reentrant spin-glass alloys ${({\mathrm{Fe}}_{x}{\mathrm{Cr}}_{1\ensuremath{-}x})}_{75}{\mathrm{P}}_{15}{\mathrm{C}}_{10}$ suggest a true phase transition with cooperative phenomena at ${T}_{c}$ not simple deviation from Langevin paramagnetism as suggested by Rakers Beck [Phys. Rev. B 36, 8622 (1987)]...