vol.10 - Special issue: ICER 2005




    Polymer Melts and Polymer Processing
 
   No.   Author(s) - Title
Pages

   1.
 

 P. Jurczak, A. Walicka, E. Walicki and D. Michalski -- Flow A Couple-Stress Fluid Through An Annular Curvilinear Channel With One Semi-Porous Wall
 

11-18
 

   2.
 

 S.V. Kotomin and V.G. Kulichikhin -- Activation Model For Polymer And Nanocomposite Melts Flow In Fibrous Bed
 

19-20
 

   3.
 

 A. Kozłowska -- The Influence Of Soft Segments Content And Chemical Structure Of Poly(Ester-Block-Amide)S On Melt Flow Index
 

21-25
 

   4.
 

 A. Kozłowska, M. Piątek and R. Ukielski -- The Synthesis And Selected Properties Of Poly(Ester-Block-Amide)S And Poly(Amide-Block-Amide)S
 

27-32
 

   5.
 

 A. Kozłowska, M. Piątek and R. Ukielski -- The Comparison Of Properties Of Terpoly(Ester-B-Ether-B-Amide)S With Aromatic/Aliphatic And Aliphatic Ester Blocks
 

33-37
 

   6.
 

 D. Michalski, E. Walicki, A. Walicka and P. Jurczak -- Pressure Drops In The Flow Through An Annular Die Of A Polymer Modelled By A Herschel-Bulkley Fluid
 

39-46
 

   7.
 

 M. Ratajczak and A. Walicka -- Flow Of An Ellis Fluid In A Clearance Between Fix Surfaces Of Revolution
 

47-54
 

   8.
 

 P. Ratajczak, E. Walicki and A. Walicka -- Influence Of Inertia And Viscoelasticity On The Flow Of A Generalized Second Grade Fluid Of A Power-Law Type Between Two Fixed Surfaces Of Revolution
 

55-62
 
 

    Analytical and Numerical Methods
 

   9.
 

 Zergua Abdesselam -- Stress – Strain Curves Of Confined Columns
 

63-68
 

   10.
 

 L. Broniarz-Press, J. Różański and T. Szczecina -- Effect Of Elbows And Sudden Contraction Of Cross-Section On Drag Reduction Effect In Surfactant Solution Flowing In Pipe System
 

69-75
 

   11.
 

 L. Broniarz-Press and D. Dulska -- Characteristics Of Falling Liquid Films Of Surfactants And Polymers Solutions
 

77-83
 

   12.
 

 L. Broniarz-Press, J. Różański, S. Różańska and A. Jur -- Drag Reducing Polymer Solutions: Pumping Effect
 

85-91
 

   13.
 

 L. Broniarz-Press, J. Bednarz and J. Różański -- Mass Transfer Enhancement In Newtonian And Non-Newtonian Liquids Flowing In Channels Of The Sinusoidal Shape
 

93-98
 

   14.
 

 R. Cortell -- A Complete Numerical Solution For The Blasius Flow
 

99-102
 

   15.
 

 T. Strek -- Ferrofluid Channel Flow Under The Influence Of Magnetic Dipole
 

103-109
 

   16.
 

 A. Uscilowska -- The Bulk Temperature In Free Convection Flow Of Carreau Fluid
 

111-117
 
 

    Biorheology and Biomimetics
 

   17.
 

 M. Dziubiński, M. Orczykowska and P. Budzyński -- Rheological Behaviour Of Aqueous Solutions Of Xanthan Gum
 

119-124
 

   18.
 

 M. Orczykowska, M. Dziubiński and P. Owczarz and E. Szwajczak -- Rheological Properties Of Synovial Fluids
 

125-129
 

   19.
 

 P. Owczarz and Z. Modrzejewska -- The Effect Of Solvent Type On Rheological Properties Of Salts
 

131-136
 

   20.
 

 M. Solecki, A. Heim and P. Owczarz and G. Kilbey, M.-L. Délia and C. Frances -- Study On The Rheological Properties Of Baker's Yeast Suspension
 

137-142
 

   21.
 

 K.Ch. Wierzcholski -- Rheological Impact In Cartilage Engineering Problems
 

143-150
 

   22.
 

 K.Ch. Wierzcholski -- Random Height Of Thin Layer Of Rheological Liquids
 

151-158
 

   23.
 

 K.Ch. Wierzcholski -- Thin Layer Of Electrorheological Liquids In Bioreactors
 

159-163
 

   24.
 

 A. Zalewska and M. Górecki -- Assessment Of Physiacl Propetries Of Macromolecules Used In Pharmacy Using Genetic Algorithms
 

165-173
 
 

    Food Rheology
 

   25.
 

 L. Broniarz-Press, J. Różański and S. Różańska -- Analysis Of The Effect Of The Special Food Additives On Rheological Properties Of Aqueous And Milk Solutions
 

175-181
 

   26.
 

 P. Wesołowski and J. Gawałek -- Concentration Effect On Density And Viscosity Of Natural Coffee Concentrates
 

183-188
 

   27.
 

 M. Witczak, L. Juszczak and T. Fortuna -- Effect of concentration on viscoelastic properties of potato starch gel
 

189-193
 

   28.
 

 M. Witczak and L. Juszczak and M. Grzesik -- Mechanical Model Of Commercial Mustards
 

195-200
 

   29.
 

 M. Witczak, A. Ptaszek, K. Surówka and D. Żmudziński -- Rheological And Afm Characteristic Of Hydrolysates Produced By Limited Enzymic Hydrolysis Of Extruded Soy Protein Concentrate
 

201-206
 
 

    Industrial Rheology
 

   30.
 

 L. Broniarz-Press, J. Sadowska, J. Różański and W. Szaferski -- The Effect Of Green Clay Addition And Torsian Polarizer On Rheological Properties Of Moisturizing Cosmetic Cream
 

207-212
 

   31.
 

 L. Broniarz-Press and S. Różańska -- Distributions Of The Local Shear Rate Values In Boundary Layer Of The Agitataed Vessel
 

213-218
 

   32.
 

 M. Gruber -- On The Implementation Of Viscoelastic Models In Commercial Cfd Programs
 

219-224
 

   33.
 

 E. Jakobsons and E. Palcevskis -- Rheology Of Dispersions Of Plasma-Processed Fine Alumina In Epoxy Resin
 

225-232
 

   34.
 

 L. Jeddi and D. Bonneau and M. El Khlifi -- Effects Of A Rayleigh Step Aspect Ratio On The Thermohydrodynamic Behavior Of Power Law Lubricant Flows
 

233-238
 

   35.
 

 P. Michaud and D. Souchet -- Thermal Behaviour Analysis Of Plain Journal Bearing Influence Of Oil Film Viscosity On The Journal Characteristics
 

245-253
 

   36.
 

 M. Mongkolwongrojn and Ch. Aiumpornsin -- Theoretical Analysis Of Journal Bearings Lubricated With Non-Newtonian Fluid Based On Carreau Viscosity Model
 

255-261
 

   37.
 

 M. Mongkolwongrojn and K. Wongseedakeaw, S. Yawong, P. Jeenkour and C. Aiumpornsin -- Effect Of Model Parameters On Elastohydrodynamic Lubrication Line Contact With Non-Newtonian Carreau Viscosity Model
 

263-268
 

   38.
 

 M. Muraki and R. Kawabata -- Effective Shear Modulus Of An Oil Flim Under Elastohydrodynamic Conditions
 

269-271
 

   39.
 

 N. Popa and M. Enescu -- The Damage Analysis On The Centrifugal Pumps Used In The Petrochemical Industry
 

273-278
 

   40.
 

 S. Raadnui and S. Mahathanabodee -- Palm Oil Based Coolant For Metalworking
 

279-284
 

   41.
 

 S. Raadnui and P. Timlerk -- The Development Of Coolant Recycling Unit
 

285-290
 

   42.
 

 S. Raadnui -- Minimum Quantity Lubrication Of Cast Iron Turning Process
 

291-296
 

   43.
 

 S. Raadnui and M.H. Narasingha -- Palm Based Oil Anti-Oxidation Behaviour Improvement: Utilization Of Epoxidation Process
 

297-302
 

   44.
 

 D. Souchet, F. Bouyahia and M. Hajjam and M. El Khlifi -- Analysis Of Tilting Pads Thrust Bearings Behavior Lubricated By Power Law Fluid
 

303-308
 
 

    Suspensions, Emulsions, Dispersions, Gels
 

   45.
 

 M. Dziubiński, A. Witczak-Stawicka and M. Orczykowska -- Study Of Suspension Stability. Models For Describing Shear Dependent Behavior
 

309-314
 

   46.
 

 J. Falicki and A. Walicka -- Effect Of Choose Oil Additive On Rheological Properties Of Engine Oils
 

315-322
 

   47.
 

 J. Gasparoux, T. Tixier and Ph. Tordjeman -- Viscoelasticity Of Polydimethylsiloxane At The Sol-Gel Threshold: Structural Effects
 

323-327
 

   48.
 

 M. Laka and S. Chernyavskaya and E. Jakobsons -- Properties Of Chitosan And Microcrystalline Cellulose Composite Gels
 

201-206
 

   49.
 

 J. Sęk and K. Krynke -- Viscosity Equation For Polydisperse Concentrated Emulsions
 

329-334
 

 














1.

FLOW A COUPLE-STRESS FLUID THROUGH AN ANNULAR CURVILINEAR CHANNEL WITH ONE SEMI-POROUS WALL

P. JURCZAK, A. WALICKA, E. WALICKI AND D. MICHALSKI

University of Zielona Góra, Department of Mechanics
65-246 Zielona Góra, ul. Szafrana 2, POLAND
e-mail: P.Jurczak@ibem.uz.zgora.pl

     The flow of a couple –stress fluid in an annular curvilinear channel with a porous insert is considered. The porous insert is connected with a inner impermeable rotating surface which approaches the outer fixed surface of an annular curvilinear channel. The equations of motion governing of the flow reduce to the coupled Reynolds and Poisson equations which can be uncoupled by using the Morgan-Cameron approximation and closed-form solution can be obtained. Expressions for the pressure distribution in a channel clearance are given. As an example the flow through the channel modelled by two concentric spherical surfaces is discussed.

Key words:

annular curvilinear channel, couple-stress fluid, pressure distribution.

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2.

ACTIVATION MODEL FOR POLYMER AND NANOCOMPOSITE MELTS FLOW IN FIBROUS BED

S.V. KOTOMIN and V.G. KULICHIKHIN

A.V. Topchiev Institute of Petrochemical Synthesis
Leninskii Pr., 29, 119991 Moscow, RUSSIA
e-mail: svk@ips.ac.ru

     Flow of confined polymer melts in narrow channels is considered on base of the activation model for polymer melt friction. While melt infiltrates a dense fibrous bed under high pressure, the polymer segments in the adsorbed layer are gradually involved in flow and the effective activation energy increases as compared with that for the melt in bulk. The theoretical prediction was proved experimentally.

Key words:

activation model, confined melt, infiltration, fibrous bed.

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3.

THE INFLUENCE OF SOFT SEGMENTS CONTENT AND CHEMICAL STRUCTURE OF POLY(ESTER-block-AMIDE)S ON MELT FLOW INDEX

A. KOZŁOWSKA

Polymer Institute, Szczecin University of Technology
Pulaskiego 10, 70-322 Szczecin, POLAND
e-mail: agak@ps.pl

     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 were used as diamine. The copolymers were obtained with changing mass ratio of the both segments and molecular weight of oligoamide soft block. Paper describes the melt flow index of poly(ester-block-amide)s in relation to the contents and structure of the soft oligoamide blocks. Rheological properties were found to depend on kind of used diamine and soft segment content in copolymer.

Key words:

multiblock thermoplastic elastomers, dimerized fatty acid, melt flow index

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4.

THE SYNTHESIS AND SELECTED PROPERTIES OF POLY(ESTER-block-AMIDE)S AND POLY(AMIDE-block-AMIDE)S

A. KOZŁOWSKA, M. PIĄTEK and R. UKIELSKI

Polymer Institute, Szczecin University of Technology
Pulaskiego 10, 70-322 Szczecin, POLAND
e-mail: agak@ps.pl

     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 of these copolymers have been investigated as function of chemical structure and the hard/soft blocks ratio. Investigations revealed that the copolymers behave as typical thermoplastic elastomers.

Key words:

multiblock thermoplastic elastomers, dimerized fatty acid, PA12, soft segment.

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5.

THE COMPARISON OF PROPERTIES OF TERPOLY(ESTER-b-ETHER-b-AMIDE)S WITH AROMATIC/ALIPHATIC AND ALIPHATIC ESTER BLOCKS

A. KOZŁOWSKA, M. PIĄTEK and R. UKIELSKI

Polymer Institute, Szczecin University of Technology
Pulaskiego 10, 70-322 Szczecin, POLAND
Atlanta, GA 30332-0405, USA
e-mail: agak@ps.pl

     Two series of multiblock terpolymers, terpoly(ester-b-ether-b-amide) (TEEA) and terpoly(estersoft-b-ether-b-amide) (TEsEA), with the same type of oligoamide (oligolaurolactam (PA12)) hard block and oligoether (oligooxytetramethylene diol (PTMO) soft block were obtained. Oligo(butylene sebacate) was used as oligoester soft block in the first series and oligo(butylene terephthalate) hard block in the second one. The influence of changes in chemical composition of ester block on the structure and thermal and mechanical properties of the terpolymers have been determined by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and other standard physical methods

Key words:

terpoly(ester-b-ether-b-amides), multiblock terpolymers, phase structure, mutual solubility of soft and hard blocks.

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6.

PRESSURE DROPS IN THE FLOW THROUGH AN ANNULAR DIE OF A POLYMER MODELLED BY A HERSCHEL-BULKLEY FLUID

D. MICHALSKI, E. WALICKI, A. WALICKA and P. JURCZAK

University of Zielona Góra, Department of Mechanics
65-246 Zielona Góra, ul. Szafrana 2, POLAND
e-mail: D.Michalski@ibem.uz.zgora.pl

     Technologies applied in polymer processing require permanent improvement by better recognition of material properties of polymer, mechanisms of process and physical phenomena arising in processing. In the work a polymer flow in an annular die modelled as narrow clearance between two fixed surfaces of revolution is considered. The problem is described by boundary layer equations. Using the method of averaged inertia one obtains the formulae expressing the pressure distribution. Generally, the flow of polymer given by the nonlinear model of Shulman is considered. The molten polymer modelled by a Herschel-Bulkley model flowing through an annular spherical channel is discussed in detail.

Key words:

annular spherical channel, viscoplastic fluid, Herschel-Bulkley fluid, pressure decrease.

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7.

FLOW OF AN ELLIS FLUID IN A CLEARANCE BETWEEN FIX SURFACES OF REVOLUTION

M. RATAJCZAK and A. WALICKA

University of Zielona Góra, Department of Mechanics
65-246 Zielona Góra, ul. Szafrana 2, POLAND
e-mail: M.Ratajczak@ibem.uz.zgora.pl

     In this paper the authors present the flow of a pseudo-plastic fluid in curvilinear clearances between fix surfaces of revolution. The problem was solved using the Ellis fluid. Solving the equations of motion presented in an orthogonal curvilinear coordinate system formulae describing the pressure distribution were obtained. As an example the flow between two discs is considered.

Key words:

pseudo-plastic fluid, Ellis model, clearance between two discs.

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8.

INFLUENCE OF INERTIA AND VISCOELASTICITY ON THE FLOW OF A GENERALIZED SECOND GRADE FLUID OF A POWER-LAW TYPE BETWEEN TWO FIXED SURFACES OF REVOLUTION

P. RATAJCZAK, E. WALICKI and A. WALICKA

University of Zielona Góra, Department of Mechanics
ul. Szafrana 2, P.O.Box 47, 65-516 Zielona Góra, POLAND
e-mail: P.Ratajczak@ibem.uz.zgora.pl

-- Full abstract click here --
Key words:

inertia effect, generalized fluid, power-law fluid.

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9.

STRESS – STRAIN CURVES OF CONFINED COLUMNS

ZERGUA ABDESSELAM

Department of Civil Engineering, University of Constantine, ALGERIA
e-mail: zergua_abdeslem@yahoo.fr

     This research is achieved in the general frame work of the study of the concrete behaviour. It has for objective the development of a numerical tool able to predict the behaviour of confined reinforced concrete columns with circular and square cross sections under increasing compressive load. The concrete behaviour is assumed as elastic – plastic model with associated flow rule in compression region and as elastic with tension stiffening behavior in the tension region. Two failure criterions have been taken into account according to the Drucker – Prager and Rankine criterion. An elastic strain hardening model has been used for the reinforcing steel. A finite element method using solid cube elements for concrete, and bar elements for the reinforcement has been adopted. Good agreement has been observed in comparing numerical results with those issued from the literature.

Key words:

reinforced concrete column, elasto-plastic modelling, numerical simulation, finite elements, transverse reinforcement.

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10.

EFFECT OF ELBOWS AND SUDDEN CONTRACTION OF CROSS-SECTION ON DRAG REDUCTION EFFECT IN SURFACTANT SOLUTION FLOWING IN PIPE SYSTEM

L. BRONIARZ-PRESS, J. RÓŻAŃSKI and T. SZCZECINA

Division of Chemical Engineering and Equipment, Faculty of Chemical Technology
Poznan University of Technology, PL 60-965 Poznań, POLAND
e-mail: lubomira.broniarz-press@put.poznan.pl

     The effect of the local frictions on drag reduction in a flow of surfactant solutions in the pipeline system has been studied. The experimental tests for aqueous solutions of hexadecyltrimethylammonium chloride of the concentration of 50, 100 and 150ppm, have been carried out. The flow in straight tubes as well in the pipeline system elements such as elbows and sudden contraction in cross-section has been tested. On the basis of the experimental data it was shown that the presence of the elements giving the local resistances in the pipeline system will bring about the decrease in flow drag reduction effect. The effect can be explained by existing in the systems tested the additional stresses caused by the constructional elements. The additional stresses cause the partial destruction of the shear induced structure SIS (responsible for the flow stabilization) and the decrease of the drag reduction effect.

Key words:

surfactant solution, drag reduction, local resistance of flow, sudden contraction, elbow.

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11.

CHARACTERISTICS OF FALLING LIQUID FILMS OF SURFACTANTS AND POLYMERS SOLUTIONS

L. BRONIARZ-PRESS and D. DULSKA

Division of Chemical Engineering and Equipment, Faculty of Chemical Technology
Poznań University of Technology, PL 60-965 Poznań, POLAND
e-mail: lubomira.broniarz-press@put.poznan.pl

     In the present work the results of the studies on the effect of surface active-agents and polymers on a mean film thickness have been presented. The experimental studies on mean thickness of a film of water and aqueous solutions of hexadecyltrimethylammonium bromide HTAB and polyacrylamide flowing down the hydrophobic organic glass plate, have been carried outIt was stated that the reduction of the film thickness is observed when the shear induced structures of a polymer and surfactant are present in a solution. The best results were obtained for aqueous solutions of HTAB with addition of sodium salicylate.

Key words:

falling liquid film, mean film thickness, surfactants, polymers, shear induced structure.

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12.

DRAG REDUCING POLYMER SOLUTIONS: PUMPING EFFECT

L. BRONIARZ-PRESS and D. DULSKA

Division of Chemical Engineering and Equipment, Faculty of Chemical Technology
Poznań University of Technology, PL 60-965 Poznań, POLAND
e-mail: lubomira.broniarz-press@put.poznan.pl

-- Full abstract click here --
Key words:

drag reduction, polyacrylamide aqueous solutions, molecular weight effect, pumping effect.

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13.

MASS TRANSFER ENHANCEMENT IN NEWTONIAN AND NON-NEWTONIAN LIQUIDS FLOWING IN CHANNELS OF THE SINUSOIDAL SHAPE

L. BRONIARZ-PRESS, J. BEDNARZ and J. RÓŻAŃSKI

Division of Chemical Engineering and Equipment, Faculty of Chemical Technology
Poznań University of Technology, PL 60-965 Poznań, POLAND
e-mail: lubomira.broniarz-press@put.poznan.pl

     The aim of the present work was the study of flow phenomena of chosen Stokes fluids in the plate and sinusoidal shape channels of two various types. The first of them had the regular shape and the second one was characterized by the opponent walls displaced in the phase. The constructions of this type can be applied in processing and biotechnology where the media very often have the non-Newtonian character and the laminar flow is required. Mass transfer coefficients in modified channels observed were greater than these ones measured in the plate exchanger. The best effect was obtained for the sinusoidal channel of symmetric construction.

Key words:

shear-thinning fluids, plate exchanger, channels of sinusoidal form, mass transfer.

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14.

A COMPLETE NUMERICAL SOLUTION FOR THE BLASIUS FLOW

R. CORTELL

Departamento de Física Aplicada, Escuela Técnica Superior de Ingenieros de Caminos,
Canales y Puertos
Universidad Politécnica de Valencia, 46071 Valencia, SPAIN
e-mail: rcortell@fis.upv.es

     Flow and heat transfer in the laminar boundary-layer about a flat plate have been investigated numerically. The variations of dimensionless surface temperature and dimensionless surface temperature gradient for different values of Prandtl number can be obtained by solving only one initial value problem related to the boundary-layer cited above.

Key words:

flow and heat transfer, flat plate.

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15.

FERROFLUID CHANNEL FLOW UNDER THE INFLUENCE OF MAGNETIC DIPOLE

T. STREK

Institute of Applied Mechanics, Poznan University of Technology
ul. Piotrowo 3, 60-965 Poznan, POLAND
e-mail: tomasz.strek@put.poznan.pl

     The viscous, two-dimensional, incompressible and laminar time dependent heat transfer flow through a ferromagnetic fluid is considered in this paper. Flow takes place in channel between two parallel flat plates under the influence of the magnetic dipole located below the channel. It is assumed that there is no electric field effects and the variation in the magnetic field vector that could occur due to temperature gradients within the ferrofluid is negligible. This magneto-thermo-mechanical problem is governed by dimensionless equations. Results are obtained using computational fluid dynamics code FEMLAB with modifications to account for the magnetic term.

Key words:

heat transfer, magnetic dipole, ferrofluid, Kelvin force, thermal power

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16.

THE BULK TEMPERATURE IN FREE CONVECTION FLOW OF CARREAU FLUID

A. USCILOWSKA

Institute of Applied Mechanics, Poznan University of Technology
ul. Piotrowo 3, 60-965 Poznan, POLAND
e-mail: anita.uscilowska@put.poznan.pl

     The presented paper treats the free convection flow. The non-Newtonian fluid is under the consideration. There exist quite a lot of models of the non-Newtonian fluid, in the literature. The work proposes the model for Careau fluid. The main assumption for such fluid is the varying viscosity, dependent on the strain rate. For the Careau fluid the numerical experiment has been performed. Some remarks and conclusions are included.

Key words:

free convection flow, heat transfer, non-Newtonian fluid, the Careau fluid, viscosity.

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17.

RHEOLOGICAL BEHAVIOUR OF AQUEOUS SOLUTIONS OF XANTHAN GUM

M. DZIUBIŃSKI, M. ORCZYKOWSKA and P. BUDZYŃSKI

Faculty of Process and Environmental Engineering, Technical University of Łódź
ul. Wólczańska 213, 90-924 Łódź, POLAND
e-mail: dziubin@wipos.p.lodz.pl

     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, marmalades and cheese. In this paper, the authors present an analysis of rheological properties of xanthan gum determined during rheometric measurements and described by two rheological models, i.e. Carreau and Herschel-Bulkley models.

Key words:

xanthan gum, hydrocolloids, viscosity, elasticity.

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18.

RHEOLOGICAL PROPERTIES OF SYNOVIAL FLUIDS

M. ORCZYKOWSKA, M. DZIUBIŃSKI and P. OWCZARZ

Faculty of Process and Environmental Engineering, Technical University of Łódź
ul. Wólczańska 213, 90-924 Łódź, POLAND
e-mail: orczykow@wipos.p.lodz.pl

E. SZWAJCZAK
Department of Physics, Technical University of Rzeszow
Ul. Powstańców Warszawy 6, 35 - 959 Rzeszów, POLAND

     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 fact that hyaluronic acid determines sliding characteristics of synovia, selected rheological properties of water solutions of this acid were investigated.

Key words:

synovial fluids, hyaluronic acid, viscosity, elasticity.

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19.

THE EFFECT OF SOLVENT TYPE ON RHEOLOGICAL PROPERTIES OF CHITOSAN SALTS

P. OWCZARZ AND Z. MODRZEJEWSKA

Faculty of Process and Environmental Engineering, Technical University of Łódź, POLAND
e-mail: owczarz@wipos.p.lodz.pl

     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 solvent.

Key words:

chitosan, rheological properties, flow curves.

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20.

STUDY ON THE RHEOLOGICAL PROPERTIES OF BAKER'S YEAST SUSPENSION

M. SOLECKI, A. HEIM AND P. OWCZARZ

Department of Process Equipment, Technical University of Lodz
ul. Wolczanska 213, 93-005 Lodz, POLAND
e-mail: owczarz@wipos.p.lodz.pl

G. KILBEY, M.-L. DÉLIA and C. FRANCES
Department of Process Equipment, Technical University of Lodz
Laboratoire de Génie Chimique UMR CNRS 5503 - ENSIACET
5 rue Paulin Talabot, BP 1301, 31106 Touloues Cedex 01, FRANCE

-- Full abstract click here --
Key words:

yeast suspension, rheological properties, measuring method, measuring methodology.

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21.

RHEOLOGICAL IMPACT IN CARTILAGE ENGINEERING PROBLEMS

K.CH. WIERZCHOLSKI

Tech.Univ. Gdańsk, Faculty of Ocean Eng. & Ship Tech., Narutowicza 11, 80952 Gdańsk, POLAND
e-mail: wierzch@pg.gda.pl

Gdynia Maritime University, Faculty of Marine Engineering, Gdynia, 81225, POLAND
e-mail: wierzch@am.gdynia.pl

     Taking into account the increasing need to artificial joints for in-vitro use, this paper presents a layout of a challenge leading to detail analyzing in aspects of rheology for the tissue cultivation and regeneration and gives a step-by-step plan for designing a novel intelligent bioreactor.

Key words:

time dependent physical and geometrical non-linearity.

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22.

RANDOM HEIGHT OF THIN LAYER OF RHEOLOGICAL LIQUIDS

K.CH. WIERZCHOLSKI

Tech.Univ. Gdańsk, Faculty of Ocean Eng. & Ship Tech., Narutowicza 11, 80952 Gdańsk, POLAND
e-mail: wierzch@pg.gda.pl

Gdynia Maritime University, Faculty of Marine Engineering, Gdynia, 81225, POLAND
e-mail: wierzch@am.gdynia.pl

     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 height of the gap joint. The second event occurs for random changes of height of the gap joint caused by the asperities of cartilage surface roughness.

Key words:

rheological liquids, optimal standard deviations.

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23.

THIN LAYER OF ELECTRORHEOLOGICAL LIQUIDS IN BIOREACTORS

K.CH. WIERZCHOLSKI

Tech.Univ. Gdańsk, Faculty of Ocean Eng. & Ship Tech., Narutowicza 11, 80952 Gdańsk, POLAND
e-mail: wierzch@pg.gda.pl

Gdynia Maritime University, Faculty of Marine Engineering, Gdynia, 81225, POLAND
e-mail: wierzch@am.gdynia.pl

     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.

Key words:

control, electrorheology, tissue cultivation, bioreactor.

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24.

ASSESSMENT OF PHYSIACL PROPETRIES OF MACROMOLECULES USED IN PHARMACY USING GENETIC ALGORITHM

A. ZALEWSKA AND M. GÓRECKI

Department of Inorganic and Analytical Chemistry, K. Marcinkowski University of Medical Sciences
Grunwaldzka 6, 60-780 Poznań, POLAND
e-mail: azalew@usoms.poznan.pl

     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 parameters have been described by a genetic algorithm and compared with solver software (part of Microsoft Excel from the Office packet).

Key words:

rheological models, genetic algorithm, comparative analysis.

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25.

ANALYSIS OF THE EFFECT OF THE SPECIAL FOOD ADDITIVES ON RHEOLOGICAL PROPERTIES OF AQUEOUS AND MILK SOLUTIONS

L. BRONIARZ-PRESS, J. RÓŻAŃSKI AND S. RÓŻAŃSKA

Division of Chemical Engineering and Equipment, Faculty of Chemical Technology
Poznań University of Technology, PL 60-965 Poznań, POLAND
e-mail: lubomira.broniarz-press@put.poznan.pl

     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 were described by Ostwald-de Waele power-law. Xanthan gum solutions had rheological properties described by Herschel-Bulkley equation. Arabic gum was characterized by Newtonian properties for aqueous solution and shear-thinning properties for milk solutions.

Key words:

food additives, rheology, salt-effect, saccharose-effect, solvent effect.

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26.

CONCENTRATION EFFECT ON DENSITY AND VISCOSITY OF NATURAL COFFEE CONCENTRATES

P. WESOŁOWSKI

Institute of Chemical Technology and Engineering, Faculty of Chemical Technology
Poznań University of Technology
pl. M. Skłodowskiej-Curie 2, 60-965 Poznań, POLAND
e-mail: piotr.wesolowski@fct.put.poznan.pl

J. GAWAŁEK
Institute of Plant Origin Food Technology, Faculty of Food Science and Nutrition
The August Cieszkowski Agricultural University of Poznań
ul. Wojska Polskiego 31, 60-624 Poznań, POLAND

     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.

Key words:

coffee concentrate, rheological parameters, density, viscosity.

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27.

EFFECT OF CONCENTRATION ON VISCOELASTIC PROPERTIES OF POTATO STARCH GEL

M. WITCZAK, L. JUSZCZAK AND T. FORTUNA

Faculty of Food Technology, University of Agriculture
Balicka 122 Street, 30-149 Cracow, POLAND
e-mail: rrwitcza@cyf-kr.edu.pl

-- Full abstract click here --
Key words:

potato starch, gelatinization, rheology, viscoelastic properties.

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28.

MECHANICAL MODEL OF COMMERCIAL MUSTARDS

M. WITCZAK AND L. JUSZCZAK

Faculty of Food Technology, University of Agriculture
Balicka 122 Street, 30-149 Cracow, POLAND
e-mail: rrwitcza@cyf-kr.edu.pl

M. GRZESIK
Institute of Chemical Engineering, Polish Academy of Sciences
Bałtycka 5 Street, 44-100 Gliwice, POLAND

     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). Curves showing the time-dependent behavior of strain in the time range of 0-100s with a constant shear stress of 1Pa were obtained. The experimental data were described by a four-element mechanical model made up of an instantaneous compliance, Kelvin body, and Newtonian compliance (Burgers model) and by a six-element model made up of an instantaneous compliance, two Kelvin bodies, and Newtonian compliance. A comparison of the curve predicted with the equation and actual data reveals that the Burgers model adequately represents the data, however, better accuracy is obtained using a more complex six parameters model.

Key words:

mustard, creep, mechanical model, rheology.

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29.

RHEOLOGICAL AND AFM CHARACTERISTIC OF HYDROLYSATES PRODUCED BY LIMITED ENZYMIC HYDROLYSIS OF EXTRUDED SOY PROTEIN CONCENTRATE

M. WITCZAK, A. PTASZEK, K. SURÓWKA AND D. ŻMUDZIŃSKI

Faculty of Food Technology, University of Agriculture
Balicka 122 Street, 30-149 Cracow, POLAND
e-mail: rrwitcza@cyf-kr.edu.pl

-- Full abstract click here --
Key words:

rheology, AFM, limited proteolysis, extrusion.

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30.

THE EFFECT OF GREEN CLAY ADDITION AND TORSIAN POLARIZER ON RHEOLOGICAL PROPERTIES OF MOISTURIZING COSMETIC CREAM

L. BRONIARZ-PRESS, J. SADOWSKA, J. RÓŻAŃSKI AND W. SZAFERSKI

Division of Chemical Engineering and Equipment, Faculty of Chemical Technology
Poznań University of Technology, PL 60-965 Poznań, POLAND
e-mail: lubomira.broniarz-press@put.poznan.pl

     The object of the studies was to determine the effect of bentonite and polarizer of special construction on the rheological behaviour change and sensory attributes for moisturizing cream of the original our own production. The cream studied was the oil/water (O/W) emulsion. The measurements were directed to determine the effect of additive concentration, temperature and polarizer on rheological behaviour change of the cream tested. It has been shown that the increase of the green clay concentration causes the increase of plastic-consistency index and yield stress as well as the decrease of flow behaviour index. Additionally it has been found that with the increase of yield stress and time of polarizer use the stability of O/W emulsion tested increased.

Key words:

rheology cosmetic cream, polarizer effect, green clay effect.

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31.

DISTRIBUTIONS OF THE LOCAL SHEAR RATE VALUES IN BOUNDARY LAYER OF THE AGITATAED VESSEL

L. BRONIARZ-PRESS AND S. RÓŻAŃSKA

Division of Chemical Engineering and Equipment, Faculty of Chemical Technology
Poznań University of Technology, PL 60-965 Poznań, POLAND
e-mail: lubomira.broniarz-press@put.poznan.pl

-- Full abstract click here --
Key words:

local shear rate, electrolyte, electrochemical method.

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32.

ON THE IMPLEMENTATION OF VISCOELASTIC MODELS IN COMMERCIAL CFD PROGRAMS

M. GRUBER

Christian-Doppler-Laboratory for Computational Applied Thermofluiddynamics
Mining University of Leoben, Franz-Josef-Str.18, 8700 Leoben, AUSTRIA
e-mail: markus.gruber@unileoben.ac.at

     Although finite-volume methods have significant advantages in terms of memory usage and computational speed, traditionally finite-element based programs are used to solve complex viscoelastic fluid dynamic problems. This work presents the successful extension of the commercial, finite volume based, state-of-the-art CFD software package FLUENT® to viscoelastic fluid flow problems, a feature which is not supported by the standard version of the program. Differential viscoelastic models of Maxwell-Type are implemented utilizing two principle capabilities of the software, i.e. the possibilities to define additional transport equations for each component of the viscoelastic stress tensor and to modify this equations using the programming interface, respectively. Results of an illustrative benchmark problem are presented, demonstrating the capability and accuracy of the proposed method to perform viscoelastic flow simulations up to a Deborah number of 100.

Key words:

viscoelastic, numerical simulation, commercial software, finite volume method.

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33.

RHEOLOGY OF DISPERSIONS OF PLASMA-PROCESSED FINE ALUMINA IN EPOXY RESIN

E. JAKOBSONS

Institute of Polymer Mechanics, 23 Aizkraukles Str., LV-1006, Riga, LATVIA
e-mail: ej@edi.lv

E. PALCEVSKIS
Institute of Inorganic Chemistry, Technical University of Riga
34 Miera Str., Salaspils-1, LV-2169, LATVIA

-- Full abstract click here --
Key words:

epoxy resin, alumina, oleic acid nitride, Hypermer LP1, flow curves, vicoelasticity.

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34.

EFFECTS OF A RAYLEIGH STEP ASPECT RATIO ON THE THERMOHYDRODYNAMIC BEHAVIOR OF POWER LAW LUBRICANT FLOWS

L. JEDDI AND D. BONNEAU

Laboratoire de Mécanique des Solides (U.M.R. C.N.R.S. 6610), Université de Poitiers
4, Avenue de Varsovie, 16021 Angoul?me Cedex, FRANCE
e-mail: loubnajeddi@yahoo.fr

M. EL KHLIFI
U.F.R. de Mécanique des Fluides et de Structures, Faculté des Sciences et Techniques
B.P. 146, 20650 Mohammedia, MOROCCO

-- Full abstract click here --
Key words:

Rayleigh step aspect ratio, power law model, thermohydrodynamic.

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35.

THERMAL BEHAVIOUR ANALYSIS OF PLAIN JOURNAL BEARING INFLUENCE OF OIL FILM VISCOSITY ON THE JOURNAL CHARACTERISTICS

P. MICHAUD AND D. SOUCHET

Laboratoire de Mécanique des Solides (U.M.R C.N.R.S 6610), Université de Poitiers
4, avenue de Varsovie, 16021 Angoul?me Cedex, FRANCE
e-mail: philippe_michaud2004@yahoo.fr

     A numerical procedure is developped in order to analyse the " Tridimensional Thermohydrodynamic " behaviour of a bearing under static loading. The Reynolds equation, the energy equation in the film and the heat transfert equation in the solids are simultaneously solved using a Newton-Raphson procedure and the finite element modelisation. The numerical procedure developped incorporates a cavitation algorithm based on JFO model, which automatically predicts film rupture and reformation in the bearings. In the present study, the obtained results from this model are compared to experimentals results and numericals results from THD 2D model. The evolution of the thermal fields are presented and discussed. The comparisons showed that the THD 3D model with the cavitation algorithm is more performant than THD 2D model.

Key words:

lubrication, thermohydrodynamic, plain bearing, finite element.

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36.

THEORETICAL ANALYSIS OF JOURNAL BEARINGS LUBRICATED WITH NON-NEWTONIAN FLUID BASED ON CARREAU VISCOSITY MODEL

M. MONGKOLWONGROJN

Electro-Mechanical Engineering Lab, ReCCIT, Faculty of Engineering
King Mongkut's Institute of Technology , Ladkrabang Bangkok 10520, THAILAND
e-mail: kmmongko@kmitl.ac.th

CH. AIUMPORNSIN
King Mongkut's Institute of Technology
Ladkrabang Bangkok 10520, THAILAND

     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 with boundary conditions using finite difference technique. The linearized bearing reactions and the journal motion can be approximated to obtain the spring and damping coefficient. Static characteristics are presented as pressure profile, temperature profile, load carrying capacity and the coefficient of friction with varying the eccentricity ratio. The stiffness coefficients, damping coefficients and the stability of the journal bearing are investigated with varying the parameters of the non-Newtonian fluid model. In this study, the shear rate of non-Newtonian lubricant and the model parameters have significant effects on the characteristics of journal bearings lubricated with the non-Newtonian fluids.

Key words:

time dependent Reynolds equation, adiabatic energy equation, Carreau viscosity model, hydrodynamic journal bearings, static and dynamic characteristics of journal bearings.

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37.

EFFECT OF MODEL PARAMETERS ON ELASTOHYDRODYNAMIC LUBRICATION LINE CONTACT WITH NON-NEWTONIAN CARREAU VISCOSITY MODEL

M. MONGKOLWONGROJN

Electro-Mechanical Engineering Lab, ReCCIT, Faculty of Engineering
King Mongkut's Institute of Technology , Ladkrabang Bangkok 10520, THAILAND
e-mail: kmmongko@kmitl.ac.th

K. WONGSEEDAKEAW, S. YAWONG, P. JEENKOUR AND C. AIUMPORNSIN
Graduate student, King Mongkut's Institute of Technology, Ladkrabang Bangkok 10520, THAILAND

     The compressible elastohydrodynamic (EHD) lubrication of two surfaces under line contact has been investigated in steady state operating conditions. The modified Reynolds equation with non-Newtonian fluids has been formulated using Carreau viscosity model. The simultaneous systems of modified Reynolds and elasticity equations with boundary conditions were solved numerically using Newton Raphson technique. The performance characteristics of the elastohydrodynamic lubrication under two surfaces in line contact were calculated and presented for varying the non-Newtonian Carreau viscosity model parameters. The pressure profile, film thickness profile, load capacity were investigated in both static and dynamic conditions. This simulation showed the significant effect of model parameters on elastohydrodynamic lubrication under heavy load conditions.

Key words:

modifed Reynold eqution, elasticity equation, elastohydrodynamic Lubrication, Carreau viscosity model, Newton Raphson method.

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38.

EFFECTIVE SHEAR MODULUS OF AN OIL FLIM UNDER ELASTOHYDRODYNAMIC CONDITIONS

M. MURAKI AND R. KAWABATA

Shonan Institute of Technology, 1-1-25, Tsujido Nishikaigan
Fujisawa, Kanagawa, 251-8511, JAPAN
e-mail: muraki@mech.shonan-it.ac.jp

-- Full abstract click here --
Key words:

tribology, traction, spin, side-slip, EHD, viscoelasticity, synthetic naphthene.

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39.

THE DAMAGE ANALYSIS ON THE CENTRIFUGAL PUMPS USED IN THE PETROCHEMICAL INDUSTRY

N. POPA

University of PITEST, ROMANIA
e-mail: npopa49@yahoo.com

M. ENESCU
PETROSERV, Navodari, ROMANIA
e-mail: Mihail.Enescu@rompetrol.com

     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 and also the causes that can generate the mechanical face seals deterioration.

Key words:

centrifugal pumps, damages, mechanical face seals.

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40.

PALM OIL BASED COOLANT FOR METALWORKING

S. RAADNUI AND S. MAHATHANABODEE

Department of Production Engineering, Faculty of Engineering
King Mongkut's Institute of Technology North Bangkok
1518 Pibulsongkram Road, Bang-Sue, Bangkok, Postcode 10800, THAILAND
e-mail: s_raadnui@yahoo.co.uk

     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 success in Europe, vegetable oil based metal working oils are now being introduced in other parts of the world. This because vegetable oil cutting fluids are more environmental friendly, less of a health hazard, and superior in "boundary-condition" lubrication mode, they could become the based oil of choice for coolant formation. In this work, the performance of palm oil based coolant was evaluated in comparison with the reference commercial coolants. The aim of the test was to evaluate mineral and palm oil based coolants characteristics. In addition of specific combinations of function formulae, work piece quality and tool wear were compared.

Key words:

coolant, metalworking, palm oil.

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41.

THE DEVELOPMENT OF COOLANT RECYCLING UNIT

S. RAADNUI AND P. TIMLERK

Department of Production Engineering, Faculty of Engineering
King Mongkut's Institute of Technology North Bangkok
1518 Pibulsongkram Road, Bang-Sue, Bangkok, Postcode 10800, THAILAND
e-mail: s_raadnui@yahoo.co.uk

     Ecological aspects are gaining in our society, bearing in mind that our environment is being increasingly contaminated with all kinds of pollutants, any reduction is welcome. From an environmental point of view and compared to a number of other chemical products, waste coolants have been one of the main sources of fresh and ground water contamination. Even though mineral based oil coolant products can be relatively and rapidly biodegraded by the microorganisms present in nature, these natural degrading systems are overwhelmed by the volume of the losses. Hence, the development of coolant recycling unit was proposed. The unit composes of three main subunits: Hydrocyclone, Pasteurizing and aeration unit. Preliminary performance of the unit was assessed and reported.

Key words:

coolant, recycling.

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42.

MINIMUM QUANTITY LUBRICATION OF CAST IRON TURNING PROCESS

S. RAADNUI

Department of Production Engineering, Faculty of Engineering
King Mongkut's Institute of Technology North Bangkok
1518 Pibulsongkram Road, Bang-Sue, Bangkok, Postcode 10800, THAILAND
e-mail: s_raadnui@yahoo.co.uk

     The ever-changing legislation and every increasing awareness of the environment have led to a change in the production processes used up to new and especially in the production auxiliaries such as coolants. It has been widely accepted that a considerable proportion of the process costs are caused by the application of metalworking fluids. In this aspect the costs for coolant concentrates themselves played an insignificant role. The actual cost are caused by system costs, labour costs for the care and monitoring of materials, coolant recycling and water purification system and last, but not least, the cost for disposal. Despite the trends towards "dry cutting" and low friction tool coatings, there is still a need for cutting fluids, or coolants, because of their ability to improve product quality, remove heat and swarf from the tool/workpiece interface and increase tool life. This has led to much more attention being paid to the Minimum Quantity Lubrication (MQL) system. In this particular research, turning of Cast Iron (CI) work pieces with MQL system has been carried out. The influences of MQL on tool wear mode/mechanism and surface roughness of workpiece was assesed and compared with conventional flood-type coolant system. In short, the results showed that surface finish and tool wear were all affected beneficially with all the MQL techniques compared to original flood-type coolant system.

Key words:

cast iron, lubrication, turning.

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43.

PALM BASED OIL ANTI-OXIDATION BEHAVIOUR IMPROVEMENT: UTILIZATION OF EPOXIDATION PROCESS

S. RAADNUI AND M.H. NARASINGHA

Department of Production Engineering, Faculty of Engineering
King Mongkut's Institute of Technology North Bangkok
1518 Pibulsongkram Road, Bang-Sue, Bangkok, Postcode 10800, THAILAND
e-mail: s_raadnui@yahoo.co.uk

     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 research on palm based oil anti-oxidation characteristic assessment was carried out. Mainly, the utilization of "epoxidation process" has been exposed. The key influencing epoxidation parameters on the response varaiable "anti-oxidation characteristic" has been asessed and reported.

Key words:

epoxidation, palm oil.

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44.

ANALYSIS OF TILTING PADS THRUST BEARINGS BEHAVIOR LUBRICATED BY POWER LAW FLUID

D. SOUCHET, F. BOUYAHIA AND M. HAJJAM

Université de Poitiers, Laboratoire de Mécanique des Solides C.N.R.S. U.M.R. 6610
4, Avenue de Varsovie, 16021 Angoul?me Cedex, FRANCE
e-mail: f_bouyahia@yahoo.fr

M. EL KHLIFI
Université Hassan II - Mohammedia, Faculté des Sciences et Techniques
BP 146, 20650 Mohammedia, MAROC

     The numerical modeling of non-Newtonian lubricant flows in titling pads thrust bearing is developed to predict some interesting factors in industrial view point. It means parameters such as load, friction and power loss whose evaluation contributes strongly to improve the design and performances of the titling pads thrust bearing. The non-Newtonian rheological model chosen is the power law because of its large domain of use. The dynamic field is described through the resolution of the generalized Reynolds equation and the thermal effects, due to the lubricant shearing, is taken into account through a global thermal balance. The discretisation of equations is made by the finite differences scheme.

Key words:

tilting pads thrust bearing, lubrication, non-Newtonian fluids, power loss.

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45.

STUDY OF SUSPENSION STABILITY. MODELS FOR DESCRIBING SHEAR DEPENDENT BEHAVIOR

M. DZIUBIŃSKI, A. WITCZAK-STAWICKA AND M. ORCZYKOWSKA

Faculty of Process and Environmental Engineering, Technical University of Łódź
ul. Wólczańska 213, 90-924 Łódź, POLAND
e-mail: dziubin@wipos.p.lodz.pl

     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. Rheological properties and especially their concentration dependence can provide detailed information about the microstructure of the suspension. Results of investigations on the effect of particle properties and various types of thickeners on rheological parameters of suspensions to be applied in the pharmaceutical industry, are presented in this study.

Key words:

pharmaceutical suspensions, rheology, stability of suspensions.

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46.

EFFECT OF CHOOSE OIL ADDITIVE ON RHEOLOGICAL PROPERTIES OF ENGINE OILS

J. FALICKI AND A. WALICKA

University of Zielona Góra, Department of Mechanics
65-246 Zielona Góra, ul. Szafrana 2, POLAND
e-mail: J.Falicki@ibem.uz.zgora.pl

     Each engine oil contains improving additives. Despite this, however, there are many individual oil additives on the market, which aim at improving the properties of oils offered. The main purpose of these additives is to lower friction, regenerate mating parts and prolong the time between oil changes. Motor-Life is one of such agents. The main objective of the present paper is to test the effects of this agent on rheological properties of oil.

Key words:

oil additives, rheological properties.

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47.

VISCOELASTICITY OF POLYDIMETHYLSILOXANE AT THE SOL-GEL THRESHOLD: STRUCTURAL EFFECTS

J. GASPAROUX, T. TIXIER AND PH. TORDJEMAN

Laboratoire d'Analyse des Interfaces et de Nanophysique - UMR-5011
Université Montpellier 2 cc 082 - Place E. Bataillon
34095 Montpellier Cedex 5 - FRANCE
e-mail: jgasp@lain.univ-montp2.fr

-- Full abstract click here --
Key words:

sol-gel transition, fractal dimension, Rouse dynamics.

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48.

PROPERTIES OF CHITOSAN AND MICROCRYSTALLINE CELLULOSE COMPOSITE GELS

M. LAKA AND S. CHERNYAVSKAYA

Latvian State Institute of Wood Chemistry
27 Dzerbenes Street, LV-1006 Riga, LATVIA
e-mail: koks@edi.lv

E. JAKOBSONS
Institute of Polymer Mechanics, Latvian University
23 Aizkraukles Street, LV-1006 Riga, LATVIA

     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. The dependence of the viscosity of composite gels on the MCC content has an extreme character with a minimum. When the MCC content reaches the value at which a liquid crystalline structure is formed in the composite gel, viscosity decreases somewhat. A study of the properties of the films has shown that, with increasing MCC content up to 65%, the tensile stress and modulus of elasticity of the film samples increase, while elongation at break, water vapour sorption and swelling decrease. This can be explained mainly by the formation of bonds between the MCC carbonyl and carboxyl groups and chitosan amino groups.

Key words:

chitosan, microcrystalline cellulose, composite gels, viscosity, tensile stress, modulus of elasticity, relative elongation at break.

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49.

VISCOSITY EQUATION FOR POLYDISPERSE CONCENTRATED EMULSIONS

J. SĘK AND K. KRYNKE

Faculty of Process and Environmental Engineering
Technical University of Łódź, POLAND
e-mail: jerzysek@mail.p.lodz.pl

-- Full abstract click here --
Key words:

viscosity, emulsions, polydispersity.

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