It is therefore important to clearly define what information you want to collect before embarking on a measure of “viscosity” that could prove difficult or unnecessary to better qualify your product.ġ.2 Is the measure of the defined viscosity relevant? In the field of polymers, there are other viscosity values such as specific viscosity, intrinsic viscosity, and relative viscosity, which make it possible to calculate the average viscous molar mass of these polymers in solution. s (1 mPa.s = 20☌ water viscosity) or Poise or cPoise. It can consider the rheological behavior of the product, which gives it an absolute character.
#Foss viscosity meter free#
It is expressed in Stokes, cStokes or cm2/s.ĭynamic viscosity h (Eta) qualifies most formulated products it is free from the effect of density and is most measured with rotary instruments. Kinematic viscosity n (nu), resulting from a flow time measurement, takes account of gravity and concerns rather less viscous fluids and simple rheological behavior: Newtonian fluids. This frequently asked question deserves clarification as there are several viscosity values to qualify a product: All rights reserved.1 Viscosity Defined 1.1 What is the viscosity of my product? The RCT estimated by the OPT was the only milk coagulation property to show good agreement with the FRM-derived value, although this was not true for the data from late-coagulating samples.Ĭopyright © 2012 American Dairy Science Association. The relative influence of days in milk on k(20) and a(45) varied, as did the effect of parity on a(45) and that of the measuring unit of coagulation meter on k(20) and a(30). The correlations between k(20) and a(45), and milk yield varied among instruments, as did the correlations between k(20), a(30), and a(45) and milk composition, and the correlations between a(45) and pH. The between-instrument correlation coefficients were either moderate (0.48 for a(30)) or low (0.24 and 0.17 for k(20) and a(45), respectively) when the same traits were compared. The proportion of noncoagulating samples for which k(20) could be estimated differed between instruments, being less for the OPT.
33.66 mm for the OPT and the FRM, respectively). 5.36 min for the OPT and the FRM, respectively), as did the a(45) figures (41.49 vs. The average k(20) values varied greatly (8.16 vs. Milk coagulation properties measured using the OPT differed considerably from those obtained using the FRM. Extending the analysis by either instrument to 90 min permitted RCT and k(20) values to be obtained even for late-coagulating milk samples.
#Foss viscosity meter trial#
The trial was performed in the same laboratory, by the same technician, and following the same procedures. Individual milk samples of 913 Brown Swiss cows from 63 herds located in Trento Province (Italy) were analyzed for rennet coagulation time (RCT, min), curd-firming time (k(20), min), and 2 measures of curd firmness (a(30) and a(45),mm) using the 2 instruments and under identical conditions. The aim of the present study was to compare milk coagulation properties measured through a traditional mechanical device, the Formagraph (FRM Foss Electric A/S, Hillerød, Denmark), and a near-infrared optical device, the Optigraph (OPT Ysebaert SA, Frépillon, France).
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