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1
Content available Rheology of drugs for topical and transdermal delivery
Walicka A., Falicki J., Iwanowska-Chomiak B.
International Journal of Applied Mechanics and Engineering
|
2019
|
Vol. 24, no. 1
179--198
EN
Skin drug delivery systems are a constant source of interest because of the benefits that they offer to overcome many drawbacks associated with other modes of drug delivery (i.e. oral, intravenous, etc.). Because of the impermeable nature of the skin, designing a suitable drug delivery vehicle that penetrates the skin barrier is challenging. Skin drug delivery can be subdivided into topical and transdermal (Fig.1). In a topical administration the drug is intended to act at skin level, this is indicated for the treatment of skin diseases. The aim of transdermal administration is getting a systemic release and in this case the skin represents a barrier not a target. The availability of drugs or other active substances through the skin depends basically on two consecutive steps: the release of these drugs or substances from vehicle or carrier and their subsequent permeation through the skin. Hence, studies on the specific properties of vehicles or carriers, such as their rheological behaviours, are of great interest in the field of pharmaceutical products. The objective of the present study is to systematically characterize a nonlinear rheological behaviour and flow properties of drugs and drug carriers into topical and transdermal administration. To this aim, one- and threedimensional rheological models are presented, which may be used to describe drug release through the skin and through the extracellular and interstitial matrix structures. Finally, the rheological measurements of some commercial creams and ointments were made.
2
Content available remote Flows of Sisko Fluid Through Symmetrically Curved Capillary Fissures and Tubes
Walicka A., Jurczak P., Falicki J.
Machine Dynamics Research
|
2018
|
Vol. 42, No. 3
27--54
EN
This paper presents a general analytical method for deriving mathematical relationships between pressure losses and the volumetric flow rate for laminar flows of a Sisko fluid. In this paper, only the laminar flow of Sisko type fluids is considered. It was demonstrated that the method can be used to find solutions for other pseudoplastic fluids and for different hapes of fissures and tubes. It can also be a good basis for numerical integration when analytical expressions are hard to obtain due to mathematical complexities. As an example, the following cases of convergent-divergent or divergent-convergent fissures and tubes, namely: parabolic, hyperbolic, hyperbolic cosine and cosine curve were considered. For each example, the formulae for pressure losses, volumetric flow rate and flow velocity were obtained. The most general forms of these formulas can be obtained by introducing hindrance factors.
3
Content available remote Effects of Hindrance Factors on a Squeeze Film of a Porous Bearing Lubricated With a Dehaven Fluid
Walicka A., Walicki E., Jurczak P., Falicki J.
Machine Dynamics Research
|
2018
|
Vol. 42, No. 1
15--33
EN
In the paper the influence of the hindrance factors on the pressure distribution and loadcarrying capacity of a curvilinear thrust porous bearing is discussed. The equations of motion of a pseudo-plastic fluid of DeHaven are used to derive the Reynolds equation. The general considerations on the flow in a bearing clearance were presented. The analytical considerations on the flow in a thin porous layer composed of capillaries were also presented. Two models of the porous region were used, e.g.: capillary tube with constant cross-section and capillary tube with variable cross-section with rectilinear generatrices. Next, using the Morgan-Cameron approximation the modified Reynolds equation was obtained. As a result the formulae expressing pressure distribution and load-carrying capacity were obtained. Thrust radial bearing with a squeeze film of DeHaven fluid was considered as an example.
4
Content available Flows of DeHaven fluid in symmetrically curved capillary fissures and tubes
Walicka A., Falicki J., Jurczak P.
International Journal of Applied Mechanics and Engineering
|
2018
|
Vol. 23, no. 2
521--550
EN
In this paper, an analytical method for deriving the relationships between the pressure drop and the volumetric flow rate in laminar flow regimes of DeHaven type fluids through symmetrically corrugated capillary fissures and tubes is presented. This method, which is general with regard to fluid and capillary shape, can also be used as a foundation for different fluids, fissures and tubes. It can also be a good base for numerical integration when analytical expressions are hard to obtain due to mathematical complexities. Five converging-diverging or diverging-converging geometrics, viz. variable cross-section, parabolic, hyperbolic, hyperbolic cosine and cosine curve, are used as examples to illustrate the application of this method. Each example is concluded with a presentation of the formulae for the velocity flow on the outer surface of a thin porous layer. Upon introduction of hindrance factors, these formulae may be presented in the most general forms.
5
Content available Reynolds number effects in the flow of a Vočadlo electrorheological fluid in a curved gap
Walicka A., Falicki J.
International Journal of Applied Mechanics and Engineering
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2017
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Vol. 22, no. 3
675--695
EN
Many electrorheological fluids (ERFs) as fluids with micro-structure demonstrate a non-Newtonian behaviour. Rheometric measurements indicate that some flows of these fluids may by modelled as the flows of a Vočadlo ER fluid. In this paper, the flow of a Vočadlo fluid – with a fractional index of non-linearity – in a narrow gap between two fixed surfaces of revolution with a common axis of symmetry is considered. The flow is externally pressurized and it is considered with inertia effect. In order to solve this problem the boundary layer equations are used. The Reynolds number effects (the effects of inertia forces) on the pressure distribution are examined by using the method of averaged inertia terms of the momentum equation. Numerical examples of externally pressurized flows in the gap between parallel disks and concentric spherical surfaces are presented.
6
Content available Influence of wall porosity and surfaces roughness on the steady performance of an externally pressurized hydrostatic conical bearing lubricated by a Rabinowitsch fluid
Walicka A., Walicki E., Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2017
|
Vol. 22, no. 3
717--737
EN
In the paper, the influence of both the bearing surfaces roughness as well as porosity of one bearing surface on the pressure distribution and load-carrying capacity of a curvilinear, externally pressurized, thrust bearing is discussed. The equations of motion of a pseudo-plastic Rabinowitsch fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation and Christensen theory of hydrodynamic lubrication with rough bearing surfaces the modified Reynolds equation is obtained. The analytical solution is presented; as a result one obtains the formulae expressing the pressure distribution and load-carrying capacity. Thrust radial and conical bearings, externally pressurized, are considered as numerical examples.
7
Content available Inertia and couple-stress effects in a curvilinear thrust hydrostatic bearing
Walicka A., Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2017
|
Vol. 22, no. 3
759--767
EN
The flow of a couple-stress lubricant in a clearance of a curvilinear thrust hydrostatic bearing with impermeable walls is considered. The flow in the bearing clearance is considered with inertia forces. The equations of motion are solved by an averaged inertia method. As a result, the formulae for pressure distributions without and with inertia effects were obtained. Radial thrust bearings and spherical bearings are discussed as numerical examples. It is shown that inertia effects influence the bearing performance considerably.
8
Content available Curvilinear squeeze film bearing with porous wall lubricated by a Rabinowitsch fluid
Walicka A., Walicki E., Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
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2017
|
Vol. 22, no. 2
427--441
EN
The present theoretical analysis is to investigate the effect of non-Newtonian lubricant modelled by a Rabinowitsch fluid on the performance of a curvilinear squeeze film bearing with one porous wall. The equations of motion of a Rabinowitsch fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and in a porous layer using the Morgan-Cameron approximation the modified Reynolds equation is obtained. The analytical solution of this equation for the case of a squeeze film bearing is presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. Thrust radial bearing and spherical bearing with a squeeze film are considered as numerical examples.
9
Content available Curvilinear squeeze film bearing lubricated with a DeHaven fluid or with similar fluids
Walicka A., Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
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2017
|
Vol. 22, no. 3
697--715
EN
In the paper, the model of a DeHaven fluid and some other models of non-Newtonian fluids, in which the shear strain rates are known functions of the powers of shear stresses, are considered. It was demonstrated that these models for small values of material constants can be presented in a form similar to the form of a DeHaven fluid. This common form, called a unified model of the DeHaven fluid, was used to consider a curvilinear squeeze film bearing. The equations of motion of the unified model, given in a specific coordinate system are used to derive the Reynolds equation. The solution to the Reynolds equation is obtained by a method of successive approximations. As a result one obtains formulae expressing the pressure distribution and load-carrying capacity. The numerical examples of flows of the unified DeHaven fluid in gaps of two simple squeeze film bearings are presented.
10
Content available Pressure distribution in a squeeze film spherical bearing with rough surfaces lubricated by an ellis fluid
Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
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2016
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Vol. 21, no. 3
593--610
EN
In this paper, the solution to a problem of pressure distribution in a curvilinear squeeze film spherical bearing is considered. The equations of motion of an Ellis pseudo-plastic fluid are presented. Using Christensen’s stochastic model of rough surfaces, different forms of Reynolds equation for various types of surface roughness pattern are obtained. The analytical solutions of these equations for the cases of externally pressurized bearing and squeeze film bearing are presented. Analytical solutions for the film pressure are found for the longitudinal and circumferential roughness patterns. As a result the formulae expressing pressure distribution in the clearance of bearing lubricated by an Ellis fluid was obtained. The numerical considerations for a spherical bearing are given in detail.
11
Content available Thrust bearing with rough surfaces lubricated by an Ellis fluid
Walicka A., Walicki E., Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2014
|
Vol. 19, no. 4
809--822
EN
In the paper the influence of bearing surfaces roughness on the pressure distribution and load-carrying capacity of a thrust bearing is discussed. The equations of motion of an Ellis pseudo-plastic fluid are used to derive the Reynolds equation. After general considerations on the flow in a bearing clearance and using the Christensen theory of hydrodynamic rough lubrication the modified Reynolds equation is obtained. The analytical solutions of this equation for the cases of a squeeze film bearing and an externally pressurized bearing are presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. A thrust radial bearing is considered as a numerical example.
12
Content available Porous squeeze film bearing with rough surfaces lubricated by a Bingham fluid
Walicka A., Walicki E., Jurczak P., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2014
|
Vol. 19, no. 4
795--808
EN
In the paper the effect of both bearing surfaces and the porosity of one bearing surface on the pressure distribution and load-carrying capacity of a squeeze film bearing is discussed. The equations of motion of a Bingham fluid in a bearing clearance and in a porous layer are presented. Using the Morgan-Cameron approximation and Christensen theory of rough lubrication the modified Reynolds equation is obtained. The analytical solutions of this equation for a squeeze film bearing are presented. As a result one obtains the formulae expressing pressure distribution and load-carrying capacity. A thrust radial bearing is considered as a numerical example.
13
Content available remote Reynolds number effects in the flow of a Bingham electrorheological fluid between fixed surfaces of revolution
Walicka A., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2011
|
Vol. 16, no 1
195-210
EN
Many electrorheological fluids (ERFs) as fluids with micro-structure demonstrate viscoplastic behaviours. Rheological measurements indicate that the flows of these fluids may be modelled as the flows of a Bingham fluid. Our concern in the paper is to examine the pressurized laminar flow of an ERF of a Bingham type in a narrow clearance between to fixed surfaces of revolution. In order to solve this problem the boundary layer equations are used. The Reynolds number effects (the effects of inertia forces) on pressure distribution are examined by using the averaged inertia method. Numerical examples of externally pressurized flows in the clearance between parallel disks and concentric spherical surfaces are presented.
14
Content available remote Pressurized flow of the Herschel-Bulkley fluid in a clearance between fixed surfaces of revolution
Walicka A., Falicki J.
Chemical and Process Engineering
|
2010
|
Vol. 31, z. 2
199-215
EN
Many fluids with microstructure demonstrate viscoplastic behaviours. Results of rheometric measurements indicate that some flows of these fluids may by modelled as the flows of Herschel.Bulkley fluids. In the paper, a flow of a Herschel-Bulkley fluid with a frictional index of non-linearity is considered in a narrow clearance between two fixed surfaces of revolution with a common axis of symmetry. The flow is externally pressurized and the inertia effect is considered. In order to solve this problem, the boundary layer equations are used. The influence of inertia forces on the pressure distribution is examined by the method of averaged inertia terms of the momentum equation. Numerical examples of externally pressurized flows in the clearance between parallel disks and concentric spherical surfaces are presented.
PL
Wiele płynów z mikrostrukturą przejawia zachowanie lepkoplastyczne. Wyniki pomiarów reologicznych wskazują, że niektóre przepływy takich płynów można modelować jako przepływy płynu Herschela-Bulkleya. Rozważano przepływ płynu Herschela-Bulkleya z ułamkowym indeksem nieliniowości w cienkiej szczelinie między dwiema nieruchomymi powierzchniami obrotowymi o wspólnej osi symetrii. Przepływ z uwzględnieniem bezwładności jest wymuszony zewnętrznym działaniem ciśnienia, a do rozwiązania problemu użyto równań warstwy przyściennej. Wpływ sił bezwładności uwzględniono, stosując metodę uśrednionej bezwładności. Przedstawiono przykłady przepływów wymuszonych ciśnieniem zewnętrznym w szczelinie między równoległymi tarczami oraz w szczelinie między współśrodkowymi powierzchniami kulistymi.
15
Content available remote Inertia effects in the flow of a simple casson fluid between two fixed surfaces of revolution
Walicka A., Falicki J.
Chemical and Process Engineering
|
2009
|
Vol. 30, z. 4
603-619
EN
Many fluids with microstructure demonstrate viscoplastic behaviours. Rheological measurements indicate that flows of these fluids may be modelled as flows of the Casson fluid. Our concern in the paper was to examine the pressurized flow of a simple Casson fluid in a thin clearance between two fixed surfaces of revolution. In order to solve this problem, the boundary layer equations were used. The effects of inertia forces on pressure distribution are examined by using the method of averaged inertia. Numerical examples of externally pressurized flows in the clearance between parallel disks and concentric spherical surfaces are presented.
PL
Wiele płynów z mikrostrukturą przejawia zachowania lepkoplastyczne. Reologiczne pomiary wskazują, że przepływy tych płynów można modelować jako przepływy płynu Cassona. Naszym celem w tym opracowaniu jest zbadanie ciśnieniowego przepływu prostego płynu Cassona w cienkiej szczelinie między dwiema nieruchomymi powierzchniami obrotowymi. Aby rozwiązać to zadanie, użyto równań warstwy przyściennej. Zbadano wpływ sił bezwładności na rozkład ciśnienia, stosując metodę uśrednionej bezwładności. Przedstawiono przykłady przepływów ciśnieniowych w szczelinie pomiędzy równoległymi tarczami i w szczelinie pomiędzy współśrodkowymi powierzchniami kulistymi.
16
Content available remote Pressure distribution in a curvilinear thrust hydrostatic bearing lubricated by a Herschel-Bulkley fluid
Walicka A., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2008
|
Vol. 13, no 2
543-552
EN
The flow of a Herschel-Bulkley fluid in a curvilinear thrust hydrostatic bearing is considered. The bearing is modeled by two curvilinear surfaces with common axis of symmetry. The flow in the bearing clearance is considered with inertia effect. Using the averaged inertia method the closed-form solution to the equations of motion is obtained. A step bearing is discussed as an example.
17
Content available remote Inertia effects in thrust curvilinear hydrostatic bearing lubricated by a Casson fluid
Walicka A., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2008
|
Vol. 13, no 2
553-562
EN
Many lubricants demonstrate non-Newtonian behaviours. Rheological measurements indicate that the flows of these lubricants may by modeled as the flows of a Casson fluid. In this paper theoretical aspects of hydrodynamic lubricantion of a curvilinear thrust bearing lubricated by a Casson fluid are considered. The effects of inertia forces on the pressure distribution are examined by using the method of averaged inertia. As examples step and spherical bearings are discussed.
18
Content available remote Inertia effects in a thrust curvilinear hydrostatic bearing lubricated by a Vočadlo fluid
Walicka A., Falicki J.
International Journal of Applied Mechanics and Engineering
|
2008
|
Vol. 13, no 3
817-828
EN
Many lubricants demonstrate non-Newtonian behaviours. Rheological measurements indicate that some flows of these lubricants may by modelled as the flows of a Vočadlo fluid. In this paper theoretical aspects of hydrostatic lubrication of a curvilinear thrust bearing lubricated by a Vočadlo fluid are considered. The bearing is modeled by two surfaces of revolution having a common axis of symmetry.The effects of inertia of a longitudinal flow of the Vočadlo lubricant on the pressure distribution in a bearing clearance are examined by using the method of averaged inertia. As examples step and spherical bearings are discussed.
19
Content available remote Effect of choose oil additive on rheological properties of engine oils
Falicki J., Walicka A.
International Journal of Applied Mechanics and Engineering
|
2005
|
Vol. 10, no spec
309-314
EN
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.
20
Inertia effects of viscoplastic lubricant in curved squeeze film
Walicki E., Walicka A., Falicki J.
Applied Mechanics and Engineering
|
1999
|
Vol. 4, no spec.
99-108
EN
The influence of inertia effect on the pressure distribution in a curvilinear thrust bearing with a viscoplastic squeeze film is considered. To solve this problem the boundary layer equations are used. The method of integral approaches is applied and the formulae expressing the pressure distribution are obtained. This distribution for Ostwald - de Waele, Bingham and Herschel - Bulkley fluids in the clearance between two disks is discussed in detail. It is found that the pressure increases with an increase of inertia effects and decreases with a decrease of the flow behaviour index N.
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