Search results for "VISCOSITY"
showing 10 items of 542 documents
Are we correctly measuring the rotational viscosity of heterogeneous bituminous binders?
2020
Modified bituminous binders allow asphalt technologists to design asphalt mixtures with superior performance. However, several recent studies highlighted that due to the complexity of these material, their characterisation can be challenging since common procedures used to characterise neat bitumen might not be adequate. For instance, during high temperature rotational viscosity testing of recycled tyre rubber modified binders (RTR-MB), a number of changes may occur to the sample leading to the here-defined sample stability which in turn provides misleading results. In this study the authors want to first provide a deeper understanding of this phenomenon by a numerical analysis using a besp…
Thermodynamics of a polymer blend solution system studied by gel permeation chromatography and viscosity
1999
Binary and ternary interaction parameters and their derivatives have been calculated with the Flory-Huggins formalism developed for a ternary polymer system. The equilibrium compositions of the ternary system tetrahydrofuran/polybutadiene/polystyrene that forms two phases in equilibrium at 25°C have been used to solve the binodal equations. With this set of parameters, the viscosimetric interaction parameters have been computed. For the sake of comparison, the experimental viscosimetric parameter has been determined from intrinsic viscosity data of a polymer (3) in a "binary solvent" (solvent + polymer (2)). It has been clearly shown that composition-dependent parameters are necessary to re…
Low compressibility accretion disc formation in close binaries: the role of physical viscosity
2006
Aims. Physical viscosity naturally hampers gas dynamics (rarefaction or compression). Such a role should support accretion disc development inside the primary gravitation potential well in a close binary system, even for low compressibility modelling. Therefore, from the astrophysical point of view, highly viscous accretion discs could exist even in the low compressibility regime showing strong thermal differences to high compressibility ones Methods. We performed simulations of stationary Smooth Particle Hydrodynamics (SPH) low compressibility accretion disc models for the same close binary system. Artificial viscosity operates in all models. The absence of physical viscosity and a superso…
Spectroscopic and Structural Investigation of the Confinement of D and L Dimethyl Tartrate in Lecithin Reverse Micelles
2009
The confinement of D and L dimethyl tartrate in lecithin reverse micelles dispersed in cyclohexane has been investigated by FT-IR, polarimetry, electronic and vibrational circular dichroism (ECD and VCD), 1H NMR, and small-angle X-ray scattering (SAXS). Measurements have been performed at room temperature as a function of the solubilizate-to-surfactant molar ratio (R) at fixed lecithin concentration. The analysis of experimental data indicates that the dimethyl tartrate molecules are solubilized within reverse micelles in proximity to the surfactant head groups in the same way for the D and L forms. The encapsulation of dimethyl tatrate within lecithin reverse micelles involves changes in i…
Solid cheese consumption: Quantification of oral coating
2011
International audience; Mouth coating, defined as the residual food that sticks to the oral surface after food ingestion, plays an important role in both the delivery of food components and mouth feel and after-feel perceptions. The aim of this work was to adapt a rapid and simple instrumental method to the quantification of food remaining after the in vivo ingestion of a solid food. This method was investigated in 12 non-trained subjects who consumed four melted cheeses differing in terms of their fat and water contents. Mouth coating was determined by fluorescence measurements using curcumin, an oil-soluble dye that had been added to the cheeses during their preparation. The results obtai…
Highly protective alkalinization by ammonia vapor diffusion in viscosimetric DNA damage assessment.
1988
A method for the measurement of viscosities correlated to DNA alterations in alkaline homogenate suspensions is described. The alkaline pH shift to afford cell lysis, DNA unfolding, and denaturation is attained by gaseous ammonia diffusion, thus avoiding shear stress from mechanical mixing. At the same time a stabilizing density gradient is established. This solution is run through a plastic measuring tube that is wide enough to minimize the influence of uneven swelling of the lysing DNA-containing components. Flow times under a carefully controlled water head are registered, and their ratios to control solutions are evaluated. The relative viscosities show a strong and irreversible depende…
Asymptotic mean value formulas for parabolic nonlinear equations
2021
In this paper we characterize viscosity solutions to nonlinear parabolic equations (including parabolic Monge–Ampère equations) by asymptotic mean value formulas. Our asymptotic mean value formulas can be interpreted from a probabilistic point of view in terms of dynamic programming principles for certain two-player, zero-sum games. peerReviewed
Rubberised bitumen manufacturing assisted by rheological measurements
2015
This paper investigates the effect of processing temperature and time on the rheological proper- ties of recycled tyre rubber-modified bitumens (RTR-MBs) produced using two different base binders and an ambient ground crumb rubber modifier (CRM). The production of the RTR- MBs was accomplished by means of a standard Brookfield rotational viscometer together with a modified impeller, dual helical impeller, to allow mixing as well as real-time viscosity measurements of the produced RTR-MBs. The rheological properties of the final RTR-MBs were determined by means of standard dynamic mechanical analysis oscillatory and multiple stress creep recovery testing using a dynamic shear rheometer. The …
Reprocessing of PLA/graphene nanoplatelets nanocomposites
2017
This work reports a study on the effect of multiple reprocessing on the properties of poly(lactic acid) (PLA) filled with graphene nanoplatelets (GnP) compared to the melt reprocessed neat polymeric matrix. In particular, morphological, X-Ray Diffraction and Micro-Raman analyses, intrinsic viscosity measurements, thermal, rheological and mechanical tests were carried out on materials reprocessed up five times by means of a single screw extruder. The results indicated that the presence of GnP decreased the degradation rate as a function of the reprocessing cycles in comparison with the neat PLA that, on the contrary, showed a more drastic reduction of the molecular weight. Moreover, the repr…
Composite soy lecithin–decylpolyglucoside vesicles: A theoretical and experimental study
2008
In the present work, vesicles made with soy lecithin and a commercial mixture of alkyl polyglucosides were prepared and characterized. Vesicles with a constant amount of soy lecithin and an increasing amount of a decylpolyglucoside surfactant, (OrNS10), were formulated and their physicochemical properties were studied with the aim to design a drug delivery system suitable for different applications. To this purpose, morphology, size distribution, ζ-potential and apparent viscosity of the prepared vesicles were studied. Vesicles were also characterized by using optical and light polarized microscopy, transmission electron microscopy and photon correlation spectroscopy. A stability study was …