Semi-concentrated

Under quiescent conditions, polymer solutions are divided into four categories depending on the average distance separating the centers of mass of the molecular coils the dilute, the semi-dilute (or semi-concentrated), the concentrated and the entangled state. 

Semi-concentrated scent provision is often presented as loose faecal or other enclosure material contained inside a sack or other receptacle. The sack is often quickly ripped apart and subsequently scent dissipated throughout the enclosure by physical action (Noonan 1999 Clark, Melfi and Mitchell 2005). 

Samples of rocks, core samples, stream sediments, panned semi-concentrate and... 

In this procedure, the sample is to semi-concentrated sulfuric acid for 24 hours. The gases released are only collected by means of diffusion in a KOH collector. 

Kosmuiski, M. et al.. Charge interactions in semi-concentrated titania suspensions at very high ionic strengths. Colloids Surf. A, 157, 245, 1999. 

Transient Effects In system where the structure changes with time upon imposition of stress, the transient effects are important. For example, semi-concentrated fiber suspensions in shear and extension show large transient peaks in the first and the second normal stress dilference [Dinh and Armstrong, 1984 Bibbo et al., 1985]. It is interesting that the peaks appear at dilferent times, first for N, then for Np and finally for... 

Semi-concentrated emulsions were examined theoretically and experimentally only within the linear viscoelastic region [Oosterbroek and Mel-lema, 1981 Oosterbroek et al., 1980, 1981 Eshuis and Mellema, 1984], Recognizing that the interphase has a final thickness (sometimes the total volume of interphase is comparable to, or even exceeds, the volume of the dispersed phase) the authors postulated that the interphase should have two interfacial coefficients, v and v facing the two principal polymer domains. Next, two models of the interphase were evaluated (i) a two-dimensional viscoelastic film, and (ii) the interphase of final thickness. Both led to at least two relaxation times ... 

Experimental data Experimentally, there are three concentration regions of emulsion flow (i) dilute for (() < 0.3, characterized by nearly Newtonian behavior semi-concentrated at 0.3 < (() < with mainly pseudoplastic character and concentrated at ( ) < (()< 1.0, showing solid-like properties with modulus and yield. 

Doi-Ohta s theory was also compared to the experimental data of semi-concentrated mixtures of PIB in PDMS [Vinckier et ai, 1997]. The theory described reasonably well the transient effects at the startup of steady state shearing. The scaling laws were also obeyed by these slightly viscoelastic blends. 

This concentration is denoted as the critical concentration c The critical concentration marks the transition from a dilute to a semi-concentrated solution. This transition is accompanied by great changes in the flow properties of a polymer solution. At concentrations above c the flow behavior is dominated by the inter-molecular interactions of the polymer coils whereas below c mainly the polymer-solvent interactions determine the flow properties. Nearly all technical applications of polymer solutions require concentrations equal to or above c. For example, the... 

The concentration of fiber suspensions is classified into three regimes dilute, semi-concentrated (or semi-dilute) and concentrated. A suspension is called dilute... 

Delaunay D, Le Bot PH, Fulchiron R, Luye JF, Regnier G (2000b) Nature of contact between polymer and mold in injection molding. Part II Influence of mold deflection on pressure history and shrinkage. Polym Eng Sci 40 1692-1700 Denn MM (2001) Extrusion instabilities and wall slip. Annu Rev Fluid Mech 33 265-287 Denn MM (2004) Fifty years of non-Newtonian fluid dynamics. AIChE J 50 2335-2345 Dinh SH, Armstrong RC (1984) A rheological equation of state for semi-concentrated fiber suspensions. J Rheol 28 207-227... 

Fedors has proposed a relationship between ( /l and c, which is valid over a wide concentration range and can be used to measure > 1 from the determination of the relative viscosity at a single polymer concentration. Nishio and Wada have observed the transition from intramolecular motion within a polystyrene molecule to a co-operative diffusion process on passing from dilute to concentrated solutions, where D also increased despite a corresponding increase in viscosity. The radius of gyration of polymers in semi-concentrated solutions has been investigated by Aharoni and Walsh. ... 

Vinckier, I., P. Moldenaers, A. M. Terracciano, and N. Grizzuti (1998). Drop size evolution during coalescence in semi-concentrated model blends, AIChEJ, 44, 951-958. 

Dinh, S. M Armstrong, R. C., A rheological equation of state for semi-concentrated fiber suspensions, J. Rheology, 28, 207-227, (1984). 

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