Search results for " viscosity"

Red blood cell deformability in multiple myeloma1.

2018

The aim of this study was the evaluation of the erythrocyte deformability in multiple myeloma (MM). We enrolled 29 MM patients and we evaluated, on fasting venous blood, the erythrocyte deformability, expressed as elongation index, and examined using the diffractometric method. By comparing normal controls and MM patients, a significant decrease in erythrocyte deformability, especially at low shear stresses, was found. In this research paper we evaluated all the hypothesis for a possible explanation of the behaviour of red blood cell deformability in MM, even considering how the alteration of erythrocyte deformability worsens the microcirculatory flow in these patients in association with t…

Hemorheological parameters in Monoclonal Gammopathy of Undetermined Significance (MGUS).

2018

There is scarcity of information about the hemorheological pattern in subjects with Monoclonal Gammopathy of Undetermined Significance (MGUS). This preliminary research is focused on the behaviour of whole-blood and plasma viscosity, haematocrit and erythrocyte deformability in the above clinical condition. We enrolled 21 MGUS subjects (10 women and 11 men; mean age 66.4 ± 11.6 years). In fasting venous blood we examined whole-blood and plasma viscosity at high and low shear rates, haematocrit, the ratios between whole-blood viscosity (at high and low shear rate) and haematocrit × 100, the ratio between plasma viscosity at low and high shear rate, and the erythrocyte deformability expressed…

Influence of lipids on blood and plasma viscosity.

2014

Amparo Vayaa,∗, Cristina Gimeneza, Rafael Alisb,c, Julian Muradoa and Oscar Fustera aHemorheology and Haemostasis Unit, Service of Clinical Pathology, La Fe University Hospital, Valencia, Spain bResearch Universitary Institute “Dr. Vina Giner”, Molecular and Mitochondrial Medicine, Catholic University of Valencia “San Vicente Martir”, Valencia, Spain cFaculty of Medicine, Catholic University of Valencia “San Vicente Martir”, Valencia, Spain

Damping by Bulk and Shear Viscosity of Confined Acoustic Phonons for Nanostructures in Aqueous Solution

2007

International audience; A nanoparticle in aqueous solution is modeled as a homogeneous elastic isotropic continuum sphere in contact with an infinite viscous compressible Newtonian fluid. The frequencies and damping of the confined vibrational modes of the sphere are calculated for the material parameters of a CdSe nanoparticle in water and a poly(methyl methacrylate) nanosphere in water. Although the effects of viscosity are found to be negligible for macroscopic objects, for nanoscale objects, both the frequency and damping of the vibrational modes are significantly affected by the viscosity of the liquid. Furthermore, both shear viscosity and bulk viscosity play an important role. A mode…

Amorphous silica between confining walls and under shear: a computer simulation study

2002

Molecular dynamics computer simulations are used to investigate a silica melt confined between walls at equilibrium and in a steady-state Poisseuille flow. The walls consist of point particles forming a rigid face-centered cubic lattice and the interaction of the walls with the melt atoms is modelled such that the wall particles have only a weak bonding to those in the melt, i.e. much weaker than the covalent bonding of a Si-O unit. We observe a pronounced layering of the melt near the walls. This layering, as seen in the total density profile, has a very irregular character which can be attributed to a preferred orientational ordering of SiO4 tetrahedra near the wall. On intermediate lengt…

First and second viscosity measurements in superfluid 3He-B

1996

By means of diaphragm-driven flow experiments in 3He-B in a thin slab geometry, we have measured the first and second viscosities, η and 3 at pressures of 0, 5, 10 and 29.3 bar. Our measurement of 3 has better established theoretical foundations than previous measurements and also extends to higher pressures. 3 and η were deduced from the frequency dependence of the flow dissipation determined from bandwidth measurements for several normal modes of the diaphragm; a first order slip correction was used in the determination of η. Near Tc, 3 α (1 - T/Tc)-1/2 in accordance with theoretical predictions but below T/Tc ~ 0.6 we observe a rapid drop in 3 signifying a departure from the hydrodynamic…

Die viscosimetrische Molekulargewichtsbestimmung von Polymeren

2006

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…

Photooxidation Behavior of a LDPE/Clay Nanocomposite Monitored through Creep Measurements

2017

Creep behavior of polymer nanocomposites has not been extensively investigated so far, especially when its effects are combined with those due to photooxidation, which are usually studied in completely independent ways. In this work, the photooxidation behavior of a low density polyethylene/organomodified clay nanocomposite system was monitored by measuring the creep curves obtained while subjecting the sample to the combined action of temperature, tensile stress, and UV radiation. The creep curves of the irradiated samples were found to be lower than those of the non-irradiated ones and progressively diverging, because of the formation of branching and cross-linking due to photooxidation. …

Improved Testing Setup for Real-Time Monitoring of PMBs During Manufacturing and Rotational Viscosity Measurements

2021

Polymer modified binders (PMBs) are a practical solution to design asphaltmixtures with superior performance. Although these polymers often improve bitumen properties to some extent, their final performance are linked to the accurate control of the properties during manufacturing and storage. However, some of the common procedures used to characterise neat bitumen are not suitable with these binders making their characterisation challenging. This study presents a novel laboratory procedure to produce SBS-MB through a real-time monitoring of the rotational viscosity, as well as an attempt to understand the suitability of current testing geometries to measure viscosity of such a complex bitum…