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Abstract

This study presents general properties of dough as demonstrated within the period of its technological usefulness (i.e, approx. up to 30 min). Eight (8) types of dough made of four (4) types of flour were subjected to experimental tests. During examination of dough, treated as a non-Newtonian fluid, its non-Newtonian (apparent) viscosity was determined as well as its correlations with other rheological quantities. The results of the study were shown in diagrams presenting the course of particular quantities and model correlations of examined types of dough. These relations were used to determine one general expression modeling rheological properties of examined doughs.
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Authors and Affiliations

Feliks Chwarścianek
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Abstract

The study discusses the issues connected with the production of thin-walled ceramic slurry in the replicast cs technology. In the ceramic mould production process, a special role is played by the liquid ceramic slurry used to produce the first layer of the mould. The study examines selected technological properties of liquid ceramic slurries used to produce moulds in the replicas cs technology. The ceramic slurries for the tests were prepared based on the binders Ludox Px30 and Sizol 030, enriched with Refracourse flour. The wettability of the pattern's surface by the liquid ceramic slurry and the dependence of the apparent viscosity on the ceramic flour content in the mixture were determined. The wettability of the pattern surface by the liquid ceramic slurry was determined based on the measurement of the wetting angle. The angle was determined by means of an analysis of the computer image obtained with the use of a CDC camera.

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Authors and Affiliations

R. Kaczorowski
T. Pacyniak
P. Just
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Abstract

This paper presents a new form of a mathematical estimation of stochastic bio-hydrodynamic lubrication parameters for real human joint surfaces with phospholipid bilayers. In this work, the authors present the analytical and stochastic considerations, which are based on the measurements of human joint surfaces. The gap is restricted between two cooperating biological surfaces. After numerous experimental measurements, it directly follows that the random symmetrical as well as unsymmetrical increments and decrements of the gap height in human joints influence the hydrodynamic pressure, load-carrying capacity, friction forces, and wear of the cooperating cartilage surfaces in human joints. The main focus of the paper was to demonstrate the influence of variations in the expected values and standard deviation of human joint gap height on the hydrodynamic lubrication parameters occurring in the human joint. It is very important to notice that the new form of apparent dynamic viscosity of synovial fluid formulated by the authors depends on ultra-thin gap height variations. Moreover, evident connection was observed between the apparent dynamic viscosity and the properties of cartilage surface coated by phospholipid cells. The above observations indicate an indirect impact of stochastic changes in the height of the gap and the indirect impact of random changes in the properties of the joint surface coated with the phospholipid layers, on the value of hydrodynamic pressure, load carrying capacity and friction forces. In this paper the authors present a synthetic, comprehensive estimation of stochastic bio-hydrodynamic lubrication parameters for the cooperating, rotational cartilage bio-surfaces with phospholipid bilayers occurring in human joints. The new results presented in this paper were obtained taking into account 3D variations in the dynamic viscosity of synovial fluid, particularly random variations crosswise the film thickness for non-Newtonian synovial fluid properties. According to the authors’ knowledge, the obtained results are widely applicable in spatiotemporal models in biology and health science.
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Authors and Affiliations

Krzysztof Wierzcholski
1
ORCID: ORCID
Andrzej Miszczak
2
ORCID: ORCID

  1. WSG University of Economy in Bydgoszcz, ul. Garbary 2, 85-229 Bydgoszcz, Poland
  2. Gdynia Maritime University, ul. Morska 81/87, 81-225 Gdynia, Poland

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