A viscometric study of the flocculation of the components in stored homogenized ultra-heat-treated cream

1982 ◽  
Vol 49 (4) ◽  
pp. 655-664 ◽  
Author(s):  
Leslie W. Phipps
Keyword(s):  
Volume Fraction ◽  
Particle Interaction ◽  
Relative Viscosity ◽  
Storage Period ◽  
Fat Globules ◽  
Heat Treated ◽  
Seasonal Factors ◽  
Image Position ◽  
Viscometric Study ◽  
Fat Volume

SUMMARYThe apparent relative viscosity (ηr) of stored homogenized ultra-heat-treated ‘coffee’ cream increased with time (t) at a rate which was a function of mean fat globule diameter (d) and fat volume fraction (ø); the rate was also influenced by Na2CO3and Na citrate when present as stabilizing additives. Viscosity increases were attributed to the progressive flocculation of fat globules and to the strengthening of the structure formed by the gradual accretion of casein micelles on to globule surfaces and their points of contact (bridging). The expressionwheretis in days anddin μm, was found to hold over a 12-week storage period for a batch of creams (ø = 0·143) of differentdvalues prepared from the bulk cream containing carbonate and citrate stabilizers; η0is the relative viscosity att= 0 andkis a rate parameter. In the absence of stabilizers the parameterkassumed a smaller value and so appeared to be a function of chemical composition of the cream and of forces of particle interaction; seasonal factors were also suspected of influencingk. The effect of the fat volume fraction on storage behaviour was not fully resolved, but there was some evidence that the proportionality log ηrα1/ø½ was appropriate.

Properties of aseptically packed ultra-heat-treated milk: Electron microscopic examination of changes occurring during storage

1977 ◽  
Vol 44 (2) ◽  
pp. 283-292 ◽  
Author(s):  
A. T. Andrews ◽  
B. E. Brooker ◽  
D. G. Hobbs
Keyword(s):  
Room Temperature ◽  
Storage Temperature ◽  
Storage Period ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Casein Micelles ◽  
Fat Globules ◽  
Micelle Size ◽  
Heat Treated ◽  
Gel Phase

SummaryChanges in the appearance of casein micelles and fat globules in ultra-heat-treated (UHT) milk were comparatively slight within a 14-month storage period although closer inspection often revealed the beginnings of some of the changes observed after even longer storage. Within this period the milks remained liquid and no evidence for any proteolytic breakdown was seen on electrophoretio examination. After 34 months the milks had all gelled and there was evidence of a small amount of proteolytic breakdown. Electron microscopic changes were striking and depended on storage temperature. At 4 °C the casein micelles in the gel phase had become very ‘spiky’ and long tendrils often bridged micelles, forming extensive networks. At room temperature and at 30 °C this tendril formation was less marked and the average micelle size was considerably greater than in freshly processed milk. There was also clear evidence for the coalescence of micelles. After storage at 37 °C the micelles were much larger than in the other samples, often exceeding 0·4 mμ in diam.

Changes in viscosity of processed creams during storage at 5 °C

1984 ◽  
Vol 51 (2) ◽  
pp. 299-305 ◽  
Author(s):  
Keith R. Langley
Keyword(s):  
Heat Treatment ◽  
Volume Fraction ◽  
Fat Content ◽  
Heat Treated ◽  
Rate Of Increase ◽  
Fat Volume

SummaryThe viscosity of heat treated creams increased with time (t). The rate (k) was dependent on homogenization pressure, fat content and heat treatment temperatures. Viscosity and its rate of increase could be related by the expressions:log η = log η0 + kt(where η0 is the viscosity at t = 0),log η0 = a1 + b1φ/d(where φ is the fat volume fraction, d is the globule diameter) andk = a2 + b2φ/d.Different values of a1b1a2 and b2 were found for homogenized and unhomogenized creams.

Changes during storage in stability and composition of ultra-heat-treated aseptically-packed cream of 18% fat content

1977 ◽  
Vol 44 (1) ◽  
pp. 111-124 ◽  
Author(s):  
M. Anderson ◽  
B. E. Brooker ◽  
T. E. Cawston ◽  
G. C. Cheeseman
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Storage Period ◽  
Fat Content ◽  
Protein Nitrogen ◽  
Nitrogen Levels ◽  
Fat Globules ◽  
Heat Treated ◽  
Different Temperatures ◽  
The Stability ◽  
Distribution Of Components

SummaryThe stability of homogenized ultra-heat-treated (UHT) aseptically-packed cream of 18 % fat content when added to hot coffee was indirectly monitored in 10 batches of cream, stored for 10 weeks at different temperatures. A tendency to coagulate under standard conditions (instability) is known as feathering. Stability was determined by a procedure in which acetate buffer instead of coffee solution was used as the test solution. The distribution of components between the fat and aqueous phases of the stored cream was also monitored. Feathering score (stability) decreased during storage but was not accompanied by any increase in non-protein nitrogen levels. The amount of casein and Ca in the fat phase of the cream increased with time and was inversely related to feathering score. Some batches of cream contained 0·1 % Na2CO3and 0·1 %Na citrate as stabilizers and these additions were found to improve feathering scores early in the storage period. Initially, the fat phase of these creams contained less casein and Ca than those without the additives, but after 10 weeks the differences in feathering score and in casein and Ca distribution, between the 2 types of cream diminished. Examination by electron microscopy showed that casein micelles were associated with fat globules, apparently linking several globules together, which was less in the creams containing additives, but after 10 weeks the appearance of all creams was similar. Electrophoretic separation of the fat globule membrane (FGM) proteins by SDS-polyacrylamide-gel electrophoresis showed that casein was the principal protein component, but that β-lactoglobulin and native FGM proteins were aslo present.

Vanadium Additions to a High-Cr White Iron and its Effects on the Abrasive Wear Behavior.

MRS Advances ◽  
2020 ◽  
Vol 5 (59-60) ◽  
pp. 3077-3089
Author(s):  
Alexeis Sánchez ◽  
Arnoldo Bedolla-Jacuinde ◽  
Francisco V. Guerra ◽  
I. Mejía
Keyword(s):  
Heat Treatment ◽  
Abrasive Wear ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Wear Behaviour ◽  
White Iron ◽  
Heat Treated ◽  
Bulk Hardness ◽  
Abrasive Wear Behavior ◽  
Vanadium Carbides

AbstractFrom the present study, vanadium additions up to 6.4% were added to a 14%Cr-3%C white iron, and the effect on the microstructure, hardness and abrasive wear were analysed. The experimental irons were melted in an open induction furnace and cast into sand moulds to obtain bars of 18, 25, and 37 mm thickness. The alloys were characterized by optical and electronic microscopy, and X-ray diffraction. Bulk hardness was measured in the as-cast conditions and after a destabilization heat treatment at 900°C for 45 min. Abrasive wear resistance tests were undertaken for the different irons according to the ASTM G65 standard in both as-cast and heat-treated conditions under a load of 60 N for 1500 m. The results show that, vanadium additions caused a decrease in the carbon content in the alloy and that some carbon is also consumed by forming primary vanadium carbides; thus, decreasing the eutectic M7C3 carbide volume fraction (CVF) from 30% for the base iron to 20% for the iron with 6.4%V;but overall CVF content (M7C3 + VC) is constant at 30%. Wear behaviour was better for the heat-treated alloys and mainly for the 6.4%V iron. Such a behaviour is discussed in terms of the CVF, the amount of vanadium carbides, the amount of martensite/austenite in matrix and the amount of secondary carbides precipitated during the destabilization heat treatment.

scholarly journals Mechanochemical Synthesis and Nitrogenation of the Nd1.1Fe10CoTi Alloy for Permanent Magnet

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3854
Author(s):  
Hugo Martínez Sánchez ◽  
George Hadjipanayis ◽  
Germán Antonio Pérez Alcázar ◽  
Ligia Edith Zamora Alfonso ◽  
Juan Sebastián Trujillo Hernández
Keyword(s):  
Mechanochemical Synthesis ◽  
Applied Field ◽  
Volume Fraction ◽  
Synthesis Method ◽  
High Energy ◽  
Direction Parallel ◽  
Best Value ◽  
Heat Treated ◽  
Bcc Phase ◽  
First Time

In this work, the mechanochemical synthesis method was used for the first time to produce powders of the nanocrystalline Nd1.1Fe10CoTi compound from Nd2O3, Fe2O3, Co and TiO2. High-energy-milled powders were heat treated at 1000 °C for 10 min to obtain the ThMn12-type structure. Volume fraction of the 1:12 phase was found to be as high as 95.7% with 4.3% of a bcc phase also present. The nitrogenation process of the sample was carried out at 350 °C during 3, 6, 9 and 12 h using a static pressure of 80 kPa of N2. The magnetic properties Mr, µ0Hc, and (BH)max were enhanced after nitrogenation, despite finding some residual nitrogen-free 1:12 phase. The magnetic values of a nitrogenated sample after 3 h were Mr = 75 Am2 kg–1, µ0Hc = 0.500 T and (BH)max = 58 kJ·m–3. Samples were aligned under an applied field of 2 T after washing and were measured in a direction parallel to the applied field. The best value of (BH)max~114 kJ·m–3 was obtained for 3 h and the highest µ0Hc = 0.518 T for 6 h nitrogenation. SEM characterization revealed that the particles have a mean particle size around 360 nm and a rounded shape.

METALLURGICAL AND CORROSION CHARACTERIZATION OF POST WELD HEAT TREATED DUPLEX STAINLESS STEEL (UNS S31803) JOINTS BY FRICTION WELDING PROCESS

2016 ◽  
Vol 23 (03) ◽  
pp. 1650013 ◽  
Author(s):  
MOHAMMED ASIF M. ◽  
KULKARNI ANUP SHRIKRISHNA ◽  
P. SATHIYA
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Friction Welding ◽  
Volume Fraction ◽  
Welding Process ◽  
Equilibrium Temperature ◽  
Weld Interface ◽  
Heat Treated ◽  
Weld Heat

The present study focuses on the metallurgical and corrosion characterization of post weld heat treated duplex stainless steel joints. After friction welding, it was confirmed that there is an increase in ferrite content at weld interface due to dynamic recrystallization. This caused the weldments prone to pitting corrosion attack. Hence the post weld heat treatments were performed at three temperatures 1080[Formula: see text]C, 1150[Formula: see text]C and 1200[Formula: see text]C with 15[Formula: see text]min of aging time. This was followed by water and oil quenching. The volume fraction of ferrite to austenite ratio was balanced and highest pit nucleation resistance were achieved after PWHT at 1080[Formula: see text]C followed by water quench and at 1150[Formula: see text]C followed by oil quench. This had happened exactly at parameter set containing heating pressure (HP):40 heating time (HT):4 upsetting pressure (UP):80 upsetting time (UP):2 (experiment no. 5). Dual phase presence and absence of precipitates were conformed through TEM which follow Kurdjumov–Sachs relationship. PREN of ferrite was decreasing with increase in temperature and that of austenite increased. The equilibrium temperature for water quenching was around 1100[Formula: see text]C and that for oil quenching was around 1140[Formula: see text]C. The pit depths were found to be in the range of 100[Formula: see text]nm and width of 1.5–2[Formula: see text][Formula: see text]m.

scholarly journals The Investigation of Effects of Temperature and Nanoparticles Volume Fraction on the Viscosity of Copper Oxide-ethylene Glycol Nanofluids

2017 ◽  
Author(s):  
Mohammad Hemmat Esfe
Keyword(s):  
Ethylene Glycol ◽  
Copper Oxide ◽  
Volume Fraction ◽  
Relative Viscosity ◽  
Experimental Results ◽  
Different Temperatures ◽  
Nanoparticles Volume Fraction ◽  
Effects Of Temperature ◽  
Nanofluid Viscosity ◽  
Experimental Values

In the present article, the effects of temperature and nanoparticles volume fraction on the viscosity of copper oxide-ethylene glycol nanofluid have been investigated experimentally. The experiments have been conducted in volume fractions of 0 to 1.5 % and temperatures from 27.5 to 50 °C. The shear stress computed by experimental values of viscosity and shear rate for volume fraction of 1% and in different temperatures show that this nanofluid has Newtonian behaviour. The experimental results reveal that in a given volume fraction when temperature increases, viscosity decreases, but relative viscosity varies. Also, in a specific temperature, nanofluid viscosity and relative viscosity increase when volume fraction increases. The maximum amount of increase in relative viscosity is 82.46% that occurs in volume fraction of 1.5% and temperature of 50 °C. Some models of computing nanofluid viscosity have been suggested. The greatest difference between the results obtained from these models and experimental results was down of 4 percent that shows that there is a very good agreement between experimental results and the results obtained from these models.

scholarly journals Effect of fat volume fraction, sodium caseinate, and starch on the optimization of the sensory properties of frankfurter sausages

2012 ◽  
Vol 1 (1) ◽  
pp. 32-44 ◽  
Author(s):  
Dimitris Petridis ◽  
Christos Ritzoulis ◽  
Iakovos Tzivanos ◽  
Eleuterios Vlazakis ◽  
Emmanuel Derlikis ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Sodium Caseinate ◽  
Sensory Properties ◽  
Fat Volume

Finite Element Analysis of Tool Particle Interaction, Particle Volume Fraction, Size, Shape and Distribution in Machining of A356/SiCp

2018 ◽  
Vol 5 (8) ◽  
pp. 16800-16806 ◽  
Author(s):  
Y.J. Nithiya Sandhiya ◽  
M.M. Thamizharasan ◽  
B.V. Ajay Subramanyam ◽  
K.S. Vijay Sekar ◽  
S. Suresh Kumar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Particle Interaction ◽  
Particle Volume ◽  
Element Analysis ◽  
Fraction Size

scholarly journals Haemorheology in dilute, semi-dilute and dense suspensions of red blood cells

2019 ◽  
Vol 872 ◽  
pp. 818-848 ◽  
Author(s):  
Naoki Takeishi ◽  
Marco E. Rosti ◽  
Yohsuke Imai ◽  
Shigeo Wada ◽  
Luca Brandt
Keyword(s):  
Red Blood Cells ◽  
Intrinsic Viscosity ◽  
Blood Cells ◽  
Volume Fraction ◽  
Relative Viscosity ◽  
Shear Plane ◽  
Constitutive Law ◽  
Stable Mode ◽  
Volume Fractions ◽  
Wide Range

We present a numerical analysis of the rheology of a suspension of red blood cells (RBCs) in a wall-bounded shear flow. The flow is assumed as almost inertialess. The suspension of RBCs, modelled as biconcave capsules whose membrane follows the Skalak constitutive law, is simulated for a wide range of viscosity ratios between the cytoplasm and plasma,$\unicode[STIX]{x1D706}=0.1$–10, for volume fractions up to$\unicode[STIX]{x1D719}=0.41$and for different capillary numbers ($Ca$). Our numerical results show that an RBC at low$Ca$tends to orient to the shear plane and exhibits so-called rolling motion, a stable mode with higher intrinsic viscosity than the so-called tumbling motion. As$Ca$increases, the mode shifts from the rolling to the swinging motion. Hydrodynamic interactions (higher volume fraction) also allow RBCs to exhibit tumbling or swinging motions resulting in a drop of the intrinsic viscosity for dilute and semi-dilute suspensions. Because of this mode change, conventional ways of modelling the relative viscosity as a polynomial function of$\unicode[STIX]{x1D719}$cannot be simply applied in suspensions of RBCs at low volume fractions. The relative viscosity for high volume fractions, however, can be well described as a function of an effective volume fraction, defined by the volume of spheres of radius equal to the semi-middle axis of a deformed RBC. We find that the relative viscosity successfully collapses on a single nonlinear curve independently of$\unicode[STIX]{x1D706}$except for the case with$Ca\geqslant 0.4$, where the fit works only in the case of low/moderate volume fraction, and fails in the case of a fully dense suspension.

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