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The rheological parameters of commercial mustards using creep-compliance technique was investigated. Seven commercial mustard not containing mustard seeds, seed pieces or spices made in Poland by different manufactures were studied. Measurements were performed using an rotationally rheometer RheoStress RS 150 (Haake, Germany) in a system of coaxial cylinders (bob diameter 40mm, cup diameter 43.4mm)...
The static and dynamic characteristics of journal bearings lubricated with non-Newtonian fluids based on Carreau viscosity model have been investigated theoretically. The time-dependent modified Reynolds equation and the adiabatic energy equations have been formulated using Carreau viscosity model. The simultaneous system of modified Reynolds and adiabatic energy equations were solved numerically...
In this paper the extension of our model (Krynke and Sęk 2004) for predicting viscosity of emulsions has been presented. It concerns highly concentrated polydisperse emulsions systems. Their structure is characterized by the fm values above 0.79. This present model has been verified using our own experimental results. On the basis of analyses of these data, it has been evaluated that z parameter of...
Macromolecular compounds have found increasing use in pharmaceutical practice as auxiliaries, in the technology of drug form as well as in the therapeutic systems with controlled release of therapeutic substances. In order to make a full use of the experimental data the system is described by mathematical rheological models by Szulman, Casson, Tscheuschmer, In the research, the values of the rheological...
Hydrocolloids, i.e. food gums, are generally applied food additives. These are water-soluble polysaccharides with thickening and/or gelating properties. One of such colloids is xanthan gum. Strong pseudoplastic properties of xanthan aqueous solutions cause enhancement of the sense of richness and savouriness of food consumed. For this reason xanthan gum is readily applied as an additive to jams, jellies,...
Hyaluronic acid forming with water a dense mucus or gel, has properties which protect delicate tissue structure against external pressures. In joints, it protects articular surfaces against the forces formed during motion. As a main component of synovial fluid, it is responsible for its viscosity. This viscosity in turn, is a very important property that characterises a bio-bed operation. Due to the...
The object of the studies was to determine the effect of various additives and solvents to Na-CMC, Guar gum (two different weight-average molecular weight), Xanthan gum and Arabic gum solutions on the change of their rheological properties. The additives studied were sodium chloride and saccharose. The solvents used were water and milk. The rheological properties of Na-CMC and guar gums solutions...
In this study the experimental analysis was performed of physical properties of highly concentrated natural instant coffee concentrates. Dependencies describing density and viscosity, determined by regression, were applied to describe minimum energy input necessary to realize the production process of coffee concentrates in a mixer with a mechanical paddle stirrer.
Two series of multiblock copolymers, poly(ester-block-amide)s (PEA) and poly(amide-block-amide)s (PAA), with the same type of oligoamide (oligolaurolactam (PA12)) hard block were obtained. Oligo(butylene adipate) was used as oligoester soft block in the first series and oligoamide soft block prepared from dimerized fatty acid and 1,6-heksametylenediamine in the second one. The selected properties...
Thermoplastic poly(ester-block-amide) elastomers (PEAs) comprising hard blocks of oligoester (oligo(butylenes terephthalate), PBT) and oligoamide soft segments (reaction product of diamines with dimerized fatty acid (DFA)) were synthesized and analysed. For preparation of oligoamide block diamine like: piperazine, 1,6-hexamethylenediamine, 1,4-cyclohexanediamine and bis-(3-aminopropyl)-polytetrahydrofuran...
Cutting oils and coolants are used to reduce friction and wear when cutting or forming metal. As well, they lubricate the cutting area, remove contaminants and prevent corrosion. There are two broad categories of conventional metalworking fluids: neat and water based. Neat cutting oils can be derived from animal, petroleum, vegetable or synthetic sources; however most are petroleum based. Having achieved...
Traction in transverse direction based on spin and side-slip was determined with a disk-on-roller machine. The measurements for di-octyl phthalate showed that the traction based on only spin was due to the elasticity of an EHL oil film from the viewpoint of rheological behaviour. Then, the influence of some parameters on the traction was examined for the synthetic naphthenes. The traction increased...
Colloidal suspension are widely used in a number of industrial applications and are usually formulated to display well-defined flow behaviour. Above a certain particle concentration suspensions are generally non-Newtonian fluids, whose flow properties are influenced by a large number of factors. The increase in particle concentrations often causes a very complex rheological behaviour of suspension...
The normal acting of an oil processing installation is determined also by the proper working of the centrifugal pumps. The preventive control process modernization has shown that a range of various frequencies damages can appear in centrifugal pumps working. The mechanical face seal is an ensemble component that can usually go wrong. This paper analyzes the damages that may appear in pumps running...
The pressure for increased use of vegetable oils in lubricants, due to both environmental and health & safety considerations, is likely to continue. In addition, economic trends are likely to make vegetable oils increasingly more attractive than in the past in many areas of the globe. All these factors will probably result in an increase use of vegetable oil as lubricants. In this work, systematic...
The rheological properties of chitosan and microcrystalline cellulose (MCC) composite gels, as well as the mechanical properties, water vapour sorption and swelling of films prepared from them were investigated. It has been shown that, on addition of liquid crystalline 9% MCC gels to non-liquid crystalline 2% chitosan gels, composite gels at sufficiently great MCC contents acquire liquid crystalline...
Rheological properties of a suspension of baker's yeast Saccharomyces cerevisiae at the concentration ranging from 0.002 to 0.17g d.w./cm3 were investigated. Flow curves were determined at the temperature 4oC by means of cylindrical rotary one- and double-gap rheometers and a capillary rheometer. A significant effect of an increasing concentration of microorganisms on the growth of apparent viscosity...
In this paper are presented the random height changes of boundary thin layer of rheological liquids occurring in joint lubrication and cartilage cultivation in bioreactors. Here are described two distribution events of the probability density function of gap height of thin liquid layer with respect to the standard deviation. The first case refer the unsteady load which causes the random changes of...
Polymers of natural origin, including chitin and products of its degradation, attract attention of biomedical engineering specialists. The presented investigations of rheological properties of chitosan salt solutions are a basis for determination of initial parameters of chitosan membrane formation. They enable determination of homogeneity of the solution and polymer degradation degree in a given...
The electromagnetic fields have a great influence on the behaviour of all the nutrient liquids occurring in bioreactors and on the living tissue. Some benefits can be taken from the effects of the electromagnetic fields on the cultivating tissue in bioreactors, namely viscosity changes of nutrient liquids, hyperthermal conditions, friction force changes.
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