Search results for "Shift factor"

Time–carbonyl groups equivalence in photo-oxidative aging of virgin/recycled polymer blends

2004

AbstractThe photo-oxidation behaviour of polymers is strongly dependent on the initial amount of carbonyl groups along the chains. The growing use of recycled post-consumer polymers coming from products used outdoors and then photo-oxidised, both pure and blended with the same virgin polymer, gives rise to an unpredictable behaviour of weathering resistance of products made with these materials. The present work shows that the carbonyl group–exposure time curves can be shifted along the time axis to give a single generalised master plot. It is then possible to predict the formation of the new carbonyl groups by knowing only the initial amount of the same carbonyl groups. The same shift fact…

UNA PROCEDURA AUTOMATIZZATA PER LA DETERMINAZIONE DELLE CURVE MAESTRE DI BITUMI PER USO STRADALE

2014

Isotope shift of40,42,44,48Ca in the 4s2S1/2→ 4p2P3/2transition

2015

We report on improved isotope shift measurements of the isotopes 40,42,44,48Ca in the 4s2S1/2→4p2P3/2 transition using collinear laser spectroscopy. Accurately known isotope shifts in the 4s2S1/2→4p2P1/2 (D1) transition were used to calibrate the ion beam energy with an uncertainty of ΔU ≈ ± 0.25 V. The accuracy in the D2 transition was improved by a factor of 5–10. A King-plot analysis of the two transitions revealed that the field shift factor in the D2 line is about 1.8(13)% larger than in the D1 transition which is ascribed to relativistic contributions of the 4p1/2 wave function.

Mechanical And Thermophysical Properties Of Polymers And Chemical Structure: From Computer Simulations To Experimental Data

1988

Chemical structure is related to properties on the basis of results of computer modelling of mechanical behavior. An equation for the shift factor aT,c dependent on temperature T and concentration c is provided, connection to the chain relaxation capability noted, and potential application range of the approach discussed. Constituents of free volume are defined, and effects of individual constituents on mechanical properties.

In-source laser spectroscopy of dysprosium isotopes at the ISOLDE-RILIS

2019

A number of radiogenically produced dysprosium isotopes have been studied by in-source laser spectroscopy at ISOLDE using the Resonance Ionization Laser Ion Source (RILIS). Isotope shifts were measured relative to $^{152}$Dy in the 4 f$^{ 10}$6s$^{2}$ $^5$I$_8$ (gs) $\rightarrow$ 4 f$^{ 10}$6s6p (8,1)$^8_o$ (418.8 nm$_{vac}$) resonance transition. The electronic factor, F, and mass shift factor, M, were extracted and used for determining the changes in mean-squared charge radii for $^{145m}$Dy and $^{147m}$Dy for the first time. A number of radiogenically produced dysprosium isotopes have been studied by in-source laser spectroscopy at ISOLDE using the Resonance Ionization Laser Ion Source (…

Rheological studies of moderately concentrated polystyrene solutions in the vicinity of the θ temperature. II. Shear-rate dependence for different th…

1983

The viscosity data of moderately concentrated polystyrene solutions in trans-decalin (TD) (θ solvent, θ temperature 21°C) and toluene (TL) (good solvent) reported in Part I are discussed in terms of Graessley's entanglement theory. Under good solvent conditions, Graessley's master curve provides an excellent fit up to high shear rates, whereas in the vicinity of the θ conditions the data have to be modified by a parameter ηfric introduced by Ito and Shishido. The characteristic time of mechanical response to flow of chains approximately given by the shift factor τ0 is found in good solvents to be on the order of the Rouse relaxation time. In poor solvents, close to demixing, τ0 tends to muc…