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1

Wettability Literature Survey Part 4: Effects of Wettability on Capillary Pressure  

Microsoft Academic Search

The capillary-pressure\\/saturation relationship depends on the interaction of wettability, pore structure, initial saturation, and saturation history. No simple relationship exists that relates the capillary pressures determined at two different wettabilities. Therefore, the most accurate measurements are made with cores that have native reservoir wettability. The article describes pore geometry and the pore medium and concludes that because of wettability, pore

W. G. Anderson

1987-01-01

2

Exploring the Impact of Wettability on Dynamic Capillary Pressure Effects  

Microsoft Academic Search

In this study a series of multistep outflow experiments was conducted with sands of varying wettability to produce data for the estimation of multiphase flow constitutive relationships using a multiphase flow parameter optimization routine. Data from separate equilibrium Pc\\/S experiments serve as independent measures of the capillary pressure\\/saturation relationship for the selected sands. A sensitivity analysis revealed that multistep outflow

D. M. O'Carroll; L. M. Abriola

2006-01-01

3

FUNDAMENTALS OF RESERVOIR SURFACE ENERGY AS RELATED TO SURFACE PROPERTIES, WETTABILITY, CAPILLARY ACTION, AND OIL RECOVERY FROM FRACTURED RESERVOIRS BY SPONTANEOUS IMBIBITION  

SciTech Connect

The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the nonwetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include novel sensitive pressure measurements designed to elucidate the basic mechanisms that determine induction time and drive the very slow rate of spontaneous imbibition commonly observed for mixed-wet rocks. In further demonstration of concepts, three approaches to improved oil recovery from fractured reservoirs will be tested; use of surfactants to promote imbibition in oil wet rocks by wettability alteration: manipulation of injection brine composition: reduction of the capillary back pressure which opposes production of oil at the fracture face.

Norman R. Morrow; Herbert Fischer; Yu Li; Geoffrey Mason; Douglas Ruth; Siddhartha Seth; Peigui Yin; Shaochang Wo

2004-10-01

4

Fundamentals of reservoir surface energy as related to surface properties, wettability, capillary action, and oil recovery from fractured reservoirs by spontaneous imbibition  

SciTech Connect

The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the nonwetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include novel sensitive pressure measurements designed to elucidate the basic mechanisms that determine induction time and drive the very slow rate of spontaneous imbibition commonly observed for mixed-wet rocks. In further demonstration of concepts, three approaches to improved oil recovery from fractured reservoirs will be tested; use of surfactants to promote imbibition in oil wet rocks by wettability alteration: manipulation of injection brine composition: reduction of the capillary back pressure which opposes production of oil at the fracture face.

Norman R. Morrow; Herbert Fischer; Yu Li; Geoffrey Mason; Douglas Ruth; Siddhartha Seth; Jason Zhengxin Tong; Peigui Yin; Shaochang Wo

2006-02-01

5

FUNDAMENTALS OF RESERVOIR SURFACE ENERGY AS RELATED TO SURFACE PROPERTIES, WETTABILITY, CAPILLARY ACTION, AND OIL RECOVERY FROM FRACTURED RESERVOIRS BY SPONTANEOUS IMBIBITION  

SciTech Connect

The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the nonwetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include novel sensitive pressure measurements designed to elucidate the basic mechanisms that determine induction time and drive the very slow rate of spontaneous imbibition commonly observed for mixed-wet rocks. In further demonstration of concepts, three approaches to improved oil recovery from fractured reservoirs will be tested; use of surfactants to promote imbibition in oil wet rocks by wettability alteration: manipulation of injection brine composition: reduction of the capillary back pressure which opposes production of oil at the fracture face.

Norman R. Morrow

2004-05-01

6

FUNDAMENTALS OF RESERVOIR SURFACE ENERGY AS RELATED TO SURFACE PROPERTIES, WETTABILITY, CAPILLARY ACTION, AND OIL RECOVERY FROM FRACTURED RESERVOIRS BY SPONTANEOUS IMBIBITION  

SciTech Connect

The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the nonwetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include novel sensitive pressure measurements designed to elucidate the basic mechanisms that determine induction time and drive the very slow rate of spontaneous imbibition commonly observed for mixed-wet rocks. In further demonstration of concepts, three approaches to improved oil recovery from fractured reservoirs will be tested; use of surfactants to promote imbibition in oil wet rocks by wettability alteration: manipulation of injection brine composition: reduction of the capillary back pressure which opposes production of oil at the fracture face.

Norman R. Morrow; Herbert Fischer; Yu Li; Geoffrey Mason; Douglas Ruth; Siddhartha Seth; Peigui Yin; Shaochang Wo

2005-04-01

7

Fundamentals of Reservoir Surface Energy as Related to Surface Properties, Wettability, Capillary Action, and Oil Recovery from Fractured Reservoirs by Spontaneous Imbibition  

SciTech Connect

The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the non-wetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include novel sensitive pressure measurements designed to elucidate the basic mechanisms that determine induction time and drive the very slow rate of spontaneous imbibition commonly observed for mixed-wet rocks. In further demonstration of concepts, three approaches to improved oil recovery from fractured reservoirs will be tested; use of surfactants to promote imbibition in oil wet rocks by wettability alteration: manipulation of injection brine composition: reduction of the capillary back pressure which opposes production of oil at the fracture face.

Norman Morrow; Herbert Fischer; Yu Li; Geoffrey Mason; Douglas Ruth; Siddhartha Seth; Zhengxin Tong; Evren Unsal; Siluni Wickramathilaka; Shaochang Wo; Peigui Yin

2008-06-30

8

Fundamentals of reservoir surface energy as related to surface properties, wettability, capillary action, and oil recovery from fractured reservoirs by spontaneous imbibition  

SciTech Connect

The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the non-wetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include novel sensitive pressure measurements designed to elucidate the basic mechanisms that determine induction time and drive the very slow rate of spontaneous imbibition commonly observed for mixed-wet rocks. In further demonstration of concepts, three approaches to improved oil recovery from fractured reservoirs will be tested; use of surfactants to promote imbibition in oil wet rocks by wettability alteration: manipulation of injection brine composition: reduction of the capillary back pressure which opposes production of oil at the fracture face.

Norman R. Morrow; Herbert Fischer; Yu Li; Geoffrey Mason; Douglas Ruth; Siddhartha Seth; Jason Zhengxin Tong; Peigui Yin; Shaochang Wo

2006-06-08

9

Fundamentals of Reservoir Surface Energy as Related to Surface Properties, Wettability, Capillary Action and Oil Recovery from Fractured Reservoirs by Spontaneous Imbibition  

SciTech Connect

The objective of this project is to increase oil recovery from fractured reservoirs through improved fundamental understanding of the process of spontaneous imbibition by which oil is displaced from the rock matrix into the fractures. Spontaneous imbibition is fundamentally dependent on the reservoir surface free energy but this has never been investigated for rocks. In this project, the surface free energy of rocks will be determined by using liquids that can be solidified within the rock pore space at selected saturations. Thin sections of the rock then provide a two-dimensional view of the rock minerals and the occupant phases. Saturations and oil/rock, water/rock, and oil/water surface areas will be determined by advanced petrographic analysis and the surface free energy which drives spontaneous imbibition will be determined as a function of increase in wetting phase saturation. The inherent loss in surface free energy resulting from capillary instabilities at the microscopic (pore level) scale will be distinguished from the decrease in surface free energy that drives spontaneous imbibition. A mathematical network/numerical model will be developed and tested against experimental results of recovery versus time over broad variation of key factors such as rock properties, fluid phase viscosities, sample size, shape and boundary conditions. Two fundamentally important, but not previously considered, parameters of spontaneous imbibition, the capillary pressure acting to oppose production of oil at the outflow face and the pressure in the non-wetting phase at the no-flow boundary versus time, will also be measured and modeled. Simulation and network models will also be tested against special case solutions provided by analytic models. In the second stage of the project, application of the fundamental concepts developed in the first stage of the project will be demonstrated. The fundamental ideas, measurements, and analytic/numerical modeling will be applied to mixed-wet rocks. Imbibition measurements will include novel sensitive pressure measurements designed to elucidate the basic mechanisms that determine induction time and drive the very slow rate of spontaneous imbibition commonly observed for mixed-wet rocks. In further demonstration of concepts, three approaches to improved oil recovery from fractured reservoirs will be tested; use of surfactants to promote imbibition in oil wet rocks by wettability alteration: manipulation of injection brine composition: reduction of the capillary back pressure which opposes production of oil at the fracture face.

Norman R. Morrow; Herbert Fischer; Yu Li; Geoffrey Mason; Douglas Ruth; Peigui Yin; Shaochang Wo

2006-12-08

10

PREDICTION OF TWO-PHASE CAPILLARY PRESSURE-SATURATION RELATIONSHIPS IN FRACTIONAL WETTABILITY SYSTEMS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Capillary pressure/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting soils. Few capillary pressure/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natura...

11

Prediction of two-phase capillary pressure saturation relationships in fractional wettability systems  

Microsoft Academic Search

Capillary pressure\\/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting porous media. Few capillary pressure\\/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natural subsurface. This work presents a new two-phase capillary pressure\\/saturation model for application to the prediction of primary drainage and imbibition

Denis M. O'Carroll; Linda M. Abriola; Catherine A. Polityka; Scott A. Bradford; Avery H. Demond

2005-01-01

12

Prediction of two-phase capillary pressure–saturation relationships in fractional wettability systems  

Microsoft Academic Search

Capillary pressure\\/saturation data are often difficult and time consuming to measure, particularly for non-water-wetting porous media. Few capillary pressure\\/saturation predictive models, however, have been developed or verified for the range of wettability conditions that may be encountered in the natural subsurface. This work presents a new two-phase capillary pressure\\/saturation model for application to the prediction of primary drainage and imbibition

Denis M. O'Carroll; Linda M. Abriola; Catherine A. Polityka; Scott A. Bradford; Avery H. Demond

2005-01-01

13

Influence of wettability variations on dynamic effects in capillary pressure  

Microsoft Academic Search

Traditional continuum-based multiphase simulators incorporate a capillary pressure-saturation relationship that assumes instantaneous attainment of equilibrium following a disturbance. This assumption may not be appropriate for systems where the capillary pressure is a function of the rate of change of saturation, a phenomenon referred to as dynamic capillary pressure. Previous studies have investigated the impact of soil and fluid properties on

Denis M. O'Carroll; Kevin G. Mumford; Linda M. Abriola; Jason I. Gerhard

2010-01-01

14

Wettability studies of filter media using capillary rise test  

Microsoft Academic Search

Filtration process is a typical tertiary treatment method for oily wastewater, suitable for the lower oil concentration and oil-in-water emulsion system. Therein the wettability of oil-in-water emulsions to filter media probably has some significant influences on the oil removal efficiency, namely a lipophilic filter medium have a better performance in oil droplets coalescence and attachment than a hydrophilic one. In

B. W. Yang; Q. Chang

2008-01-01

15

Patterning of wettability for controlling capillary-driven flow in closed channels.  

PubMed

Glass capillaries are prepared with well-defined regions of tuneable wettability on the interior walls using an inexpensive and simple approach. A homogeneous layer of hydrophilic TiO2 nanoparticles is adsorbed on the capillary wall and chemically hydrophobized using octadecyltrihydrosilane (OTHS). The hydrophobic OTHS monolayer is then patterned by spatially-selective removal of the OTHS via TiO2-catalysed decomposition by ultraviolet irradiation. By patterning the capillaries with hydrophilic-hydrophobic rings, modulated penetration of a liquid (glycerol, in this study) can be achieved. For given wettability contrast, the penetration dynamics and equilibrium rise heights are very sensitive to the characteristic length-scale of the pattern, and may offer greater, time-dependent sampling control in fluidic devices. PMID:23660024

O'Loughlin, Muireann; Priest, Craig; Popescu, Mihail N; Ralston, John

2013-04-17

16

Capillary pressure spectrometry: Toward a new method for the measurement of the fractional wettability of porous media  

NASA Astrophysics Data System (ADS)

A transparent porous medium of controlled fractional wettability is fabricated by mixing intermediate-wet glass microspheres with strongly oil-wet polytetrafluouroethylene microspheres, and packing them between two transparent glass plates. Silicon oil is displaced by water, the growth pattern is video-recorded, and the transient response of the pressure drop across the pore network is measured for various fractions of oil-wet particles. The measured global capillary pressure fluctuates as the result of the variation of the equilibrium curvature of menisci between local maxima and local minima. With the aid of wavelets, the transient response of the capillary pressure is transformed to a capillary pressure spectrum (CPS). The peaks of the CPS are used to identify the most significant flow events and correlate their amplitude with the spatial distribution of fractional wettability. The flow events are closely related with the fluctuations of the capillary pressure and are classified into three main categories: motion in pore clusters, generation/expansion of capillary fingers, coalescence of interfaces. The amplitude of the peaks of CPS is related quasilinearly with a local coefficient of fractional wettability presuming that the same class of flow events is concerned. Approximate calculations of the maximum meniscus curvature in pores of converging-diverging geometry and uniform wettability in combination with simple mixing laws predict satisfactorily the experimentally measured average prebreakthrough capillary pressure as a function of the fraction of the oil-wet particles.

Sygouni, Varvara; Tsakiroglou, Christos D.; Payatakes, Alkiviades C.

2006-05-01

17

Capillary rise in a microchannel of arbitrary shape and wettability: hysteresis loop.  

PubMed

Capillary rise in an asymmetric microchannel, in which both contact angle (wettability) and open angle (geometry) can vary with position, is investigated based on free-energy minimization. The integration of the Young-Laplace equation yields the general force balance between surface tension and gravity. The former is surface tension times the integration of cos ?(u) along the contact line, where ?(u) depicts the local difference between contact angle and open angle. The latter comes from the total volume right underneath the meniscus. For the same channel height, multiple solutions can be obtained from the force balance. However, the stable height of capillary rise must satisfy stability analysis. Several interesting cases have been studied, including short capillary, truncated cone, hyperboloid, and two different plates. As the tube length is smaller than Jurin's height, the angle of contact will be tuned to fulfill the force balance. While only one stable state is seen for divergent channels, two stable states can be observed for convergent channels. Three regimes can be identified for the plot of the stable height of capillary rise against the channel height. The higher height dominates in the short channel regime, while the lower height prevails in the tall channel regime. However, both solutions are stable in the intermediate regime. Surface Evolver simulations and experiments are performed to validate our theoretical predictions. Our results offer some implications for water transport to the tops of tall trees. A small bore at the uppermost leaf connected to a larger xylem conduit corresponds to a convergent channel, and two stable heights are possible. The slow growth of the tree can be regarded as a gradual rise of the convergent channel. Consequently, the stable height of capillary rise to the top of a tall tree can always be achieved. PMID:23171321

Wang, Zhengjia; Chang, Cheng-Chung; Hong, Siang-Jie; Sheng, Yu-Jane; Tsao, Heng-Kwong

2012-11-29

18

Spontaneous and forced imbibition of aqueous wettability altering surfactant solution into an initially oil-wet capillary.  

PubMed

Unforced invasion of wettability-altering aqueous surfactant solutions into an initially oil-filled oil-wet capillary tube has been observed to take place very slowly, and because this system is an analogue for certain methods of improved oil recovery from naturally fractured oil-wet reservoirs, it is important to identify the rate-controlling processes. We used a model for the process published by Tiberg et al. ( Tiberg , F. , Zhmud , B. , Hallstensson , K. and Von Bahr , M. Phys. Chem. Chem. Phys. 2000 , 2 , 5189 - 5196 ) and modified it for forced imbibitions. We show that when applied pressure differences are not too large invasion rates are controlled at large times by the value of the bulk diffusion coefficient for surfactant in the aqueous phase and at early times by the resistance to transfer of surfactant from the oil-water meniscus onto the walls of the capillary. For realistic values of the bulk diffusion coefficient, invasion rates are indeed slow, as observed. The model also predicts that the oil-water-solid contact angle during unforced displacement is close to pi/2, and so, the displacement occurs in a state of near-neutral wettability with the rate of invasion controlled by the rate of surfactant diffusion rather than a balance between capillary forces and viscous resistance. Under forced conditions, the meniscus moves faster, but the same kinds of dynamical balances between the various processes as were found in the spontaneous case operate. Once the capillary threshold pressure for entry into the initial oil-wet tube is exceeded, the effect of pressure on velocity becomes more significant, there is not sufficient time for the surfactant molecules to transfer in great quantity from the meniscus to the solid surface, and wettability alteration is then no longer important. PMID:19673494

Hammond, Paul S; Unsal, Evren

2009-11-01

19

The influence of wettability variations on dynamic effects in capillary pressure  

Microsoft Academic Search

Continuum-based simulators for multiphase flow in porous media commonly incorporate a constitutive expression relating capillary pressure and saturation. Following a disturbance in the capillary pressure-saturation equilibrium, these simulators often implicitly assume an instantaneous return to a new equilibrium state. However, past experiments have shown that this is not necessarily the case, and that the capillary pressure-saturation relationship can be a

K. G. Mumford; D. M. O'Carroll; L. Abriola; J. Gerhard

2009-01-01

20

The role of wettability in dynamic capillary pressure effects: fundamental considerations  

Microsoft Academic Search

Dynamic effects in capillary pressure are receiving increased attention in the literature. These effects, where capillary pressure is a function of the rate of change in saturation, have the potential to produce non-unique capillary pressure-saturation relationships, and significantly change the transient distribution of non-wetting fluids. Although multiple experimental and numerical studies have been conducted, the underlying mechanisms remain unclear. Several

K. G. Mumford; D. M. O'Carroll; L. M. Abriola

2009-01-01

21

AA Parametric Model for Predicting Relative Permeability-Saturation-Capillary Pressure Relationships of Oil?Water Systems in Porous Media with Mixed Wettability  

SciTech Connect

A parametric two-phase, oil-water relative permeability/capillary pressure model for petroleum engineering and environmental applications is developed for porous media in which the smaller pores are strongly water-wet and the larger pores tend to be intermediate- or oil-wet. A saturation index, which can vary from 0 to 1, is used to distinguish those pores that are strongly water-wet from those that have intermediate- or oil-wet characteristics. The capillary pressure submodel is capable of describing main-drainage and hysteretic saturation-path saturations for positive and negative oil-water capillary pressures. At high oil-water capillary pressures, an asymptote is approached as the water saturation approaches the residual water saturation. At low oil-water capillary pressures (i.e., negative), another asymptote is approached as the oil saturation approaches the residual oil saturation. Hysteresis in capillary pressure relations, including water entrapment, is modeled. Relative permeabilities are predicted using parameters that describe main drainage capillary pressure relations and accounting for how water and oil are distributed throughout the pore spaces of a porous medium with mixed wettability. The capillary pressure submodel is tested against published experimental data, and an example of how to use the relative permeability/capillary pressure model for a hypothetical saturation-path scenario involving several imbibition and drainage paths is given. Features of the model are also explained. Results suggest that the proposed model is capable of predicting relative permeability/capillary pressure characteristics of porous media mixed wettability.

Lenhard, Robert J. (INEEL); Oostrom, Mart (BATTELLE (PACIFIC NW LAB))

1998-01-01

22

Fractional wettability effects on two-and three-fluid capillary pressure-saturation relations  

Microsoft Academic Search

Studies of the relation between capillary pressure (Pc) and fluid saturation (S) for porous media containing oil-water or air-oil-water, often assume that the medium is strongly water-wet. Natural porous media, however, are composed of a variety of mineral constituents; such media are typically composed of water- and oil-wet fractions. This study reports on two- and three-fluid Pc-S data for media

Scott A. Bradford; Feike J. Leij

1995-01-01

23

Capillary pressure and wettability behavior of CO{sub 2} sequestration in coal at elevated pressures  

SciTech Connect

Enhanced coalbed-methane (ECBM) recovery combines recovery of methane (CH{sub 4}) from coal seams with storage of carbon dioxide (CO{sub 2}). The efficiency of ECBM recovery depends on the CO{sub 2} transfer rate between the macrocleats, via the microcleats to the coal matrix. Diffusive transport of CO{sub 2} in the small cleats is enhanced when the coal is CO{sub 2}-wet. Indeed, for water-wet conditions, the small fracture system is filled with water and the rate of CO{sub 2} sorption and CH{sub 4} desorption is affected by slow diffusion of CO{sub 2}. This work investigates the wetting behavior of coal using capillary pressures between CO{sub 2} and water, measured continuously as a function of water saturation at in-situ conditions. To facilitate the interpretation of the coal measurements, we also obtain capillary pressure curves for unconsolidated-sand samples. For medium- and high-rank coal, the primary drainage capillary pressure curves show a water-wet behavior. Secondary forced-imbibition experiments show that the medium-rank coal becomes CO{sub 2}-wet as the CO{sub 2} pressure increases. High-rank coal is CO{sub 2}-wet during primary imbibition. The imbibition behavior is in agreement with contact-angle measurements. Hence, we conclude that imbibition tests provide the practically relevant data to evaluate the wetting properties of coal.

Plug, W.J.; Mazumder, S.; Bruining, J. [Horizon Energy Partners BV, Hague (Netherlands)

2008-12-15

24

Wettability Literature Survey Part 2: Wettability Measurement  

Microsoft Academic Search

Many methods have been used to measure wettability. This paper describes the three quantitative methods in use today: contact angle, Amott method, and the U.S. Bureau of Mines (USBM) method. The advantages and limitations of all the qualitative methods-imbibition, microscope examination, flotation, glass slide, relative permeability curves, capillary pressure curves, capillarimetric method, displacement capillary pressure, permeability\\/saturation relationships, and reservoir logs-are

William Anderson

1986-01-01

25

Capillary pressure spectrometry: Toward a new method for the measurement of the fractional wettability of porous media  

Microsoft Academic Search

A transparent porous medium of controlled fractional wettability is fabricated by mixing intermediate-wet glass microspheres with strongly oil-wet polytetrafluouroethylene microspheres, and packing them between two transparent glass plates. Silicon oil is displaced by water, the growth pattern is video-recorded, and the transient response of the pressure drop across the pore network is measured for various fractions of oil-wet particles. The

Varvara Sygouni; Christos D. Tsakiroglou; Alkiviades C. Payatakes

2006-01-01

26

Wettability and Its Implications for Enhanced Oil Recovery.  

National Technical Information Service (NTIS)

Reservoir rock wettability determines capillary pressure, fluid distribution, relative permeability and electrical properties and may play an important role in waterflood recovery efficiency. This report covers a literature survey of wettability, its sign...

K. Das P. S. Puon

1985-01-01

27

Role of calcium ions in the mechanism of action of a lignosulphonate used to modify the wettability of plastics for their separation by flotation  

Microsoft Academic Search

As part of the separation by froth flotation of PVC and PET from waste bottles before recycling, the mechanism of action has been studied of a lignosulphonate used to selectively render the surface of PET hydrophilic. More specifically, an attempt has been made to determine the influence of cations.The results of the experimental study, based on flotation tests, wettability and

C. Le Guern; P. Conil; R. Houot

2000-01-01

28

Wettability Determination and Its Effect on Recovery Efficiency  

Microsoft Academic Search

A quantitative method for measuring the wettability of porous media containing brine and crude oil has been developed by the USBM using capillary pressure curves determined with a centrifuge. These measurements were reproducible within a standard deviation of 8.2 percent. The determination of fractional wettability has been compared with a method involving a combination of imbibition and displacement. Results are

ERLE DONALDSON; REX THOMAS; PHILIP LORENZ

1969-01-01

29

Profiling propolis flavonoids by means of micellar electrokinetic capillary chromatography, capillary gas chromatography and bactericidal action  

Microsoft Academic Search

Summary  There is no proportional correlation between increasing organic solvent polarity from hexane to methanol and the extractability\\u000a of propolis solids by the solvents or the bactericidal action of the propolis extracts obtained. Hexane (17.7%) and chloroform\\u000a (62.1%) were the poorest and the best extractants, respectively, for propolis solids. The antibiotic activity of the extracts\\u000a againstStaphylococcus strains decreased in the order

J. D. Fontana; M. Passos; M. H. R. dos Santos; C. K. Fontana; B. H. Oliveira; L. Schause; R. Pontarolo; M. A. Barbirato; M. A. Ruggiero; F. M. Lanças

2000-01-01

30

Wettability Literature Survey Part 1: Rock\\/Oil\\/Brine Interactions and the Effects of Core Handling on Wettability  

Microsoft Academic Search

Wettability is a major factor controlling the location, flow and distribution of fluids in a reservoir. The wettability of a core will affect almost all types of core analyses, including capillary pressure, relative permeability, waterflood behavior, electrical properties, and simulated tertiary recovery. The most accurate results are obtained when native- or restored-state cores are run with native crude oil and

William Anderson

1986-01-01

31

The Impact of Wettability on Waterflooding: Pore-Scale Simulation  

Microsoft Academic Search

This paper describes the development and implementation of a pore-scale simulator into which pore-wettability effects have been incorporated. Relative permeability and capillary pressure curves from this steady-state model have been analyzed to allow better interpretation of experimental observations from a microscopic standpoint. The simulated capillary pressure data demonstrate that some standard wettability tests (such as Amott-Harvey and free imbibition) may

S. R. McDougall; K. S. Sorbie

1995-01-01

32

A Parametric Model for Predicting Relative Permeability-Saturation-Capillary Pressure Relationships of Oil–Water Systems in Porous Media with Mixed Wettability  

Microsoft Academic Search

A parametric two-phase, oil–water relative permeability\\/capillary pressure model for petroleum engineering and environmental applications is developed for porous media in which the smaller pores are strongly water-wet and the larger pores tend to be intermediate- or oil-wet. A saturation index, which can vary from 0 to 1, is used to distinguish those pores that are strongly water-wet from those that

Robert J. Lenhard; Mart Oostrom

1998-01-01

33

Infiltration of PCE in a system containing spatial wettability variations  

Microsoft Academic Search

Abstract A two-dimensional infiltration experiment was conducted to investigate and quantify the effect of spatial wettability variations on DNAPL migration and entrapment in saturated sands. Experimental observations of tetrachloroethylene (PCE) infiltration showed,that organic-wet sand lenses acted as very effective capillary barriers, retaining PCE and inhibiting its downward migration. A multiphase numerical,simulator was,used to model,this sand box,experiment. The simulator incorporates wettability-modified

Denis M. O'Carroll; Scott A. Bradford; Linda M. Abriola

34

Wettability of porous media after exposure to synthetic gasolines  

Microsoft Academic Search

The wettability of a porous medium plays a critical role in the capillary phenomena governing the migration of a nonaqueous-phase liquid (NAPL) and subsequent efforts to recover this type of pollutant source from the subsurface. Although it is usually assumed that water-wetting conditions occur, limited field evidence at NAPL sites suggests that wettability characteristics can change to intermediate or organic-phase

Susan E. Powers; Michael E. Tamblin

1995-01-01

35

Wettability hysteresis and its implications for DNAPL source zone distribution.  

PubMed

Subsurface heterogeneity at sites contaminated with nonaqueous phase liquids (NAPLs) reduces the effectiveness of traditional remediation measures. One cause may be the increased proportion of NAPL that is hydraulically isolated due to capillary trapping in heterogeneously-wetted materials. This study examines the wettability of ten materials, ranging from minerals, such as calcite and dolomite, to carbonaceous materials, such shale and coal, in air and water, NAPL and air, and NAPL and water systems. The wettability differed depending on which phase the solid material was initially immersed in: the less crystalline solids, if initially contacted by water were water-wet, but if initially contacted by NAPL were NAPL-wet. This difference, termed here wettability hysteresis, was observed for a suite of halogenated NAPLs and was independent of equilibration time. The degree of wettability hysteresis was greatest in the NAPL and water systems, with the magnitude of the difference increasing with the carbonaceous materials. Since the degree of capillary trapping in subsurface materials is related to wettability, the phenomenon of wettability hysteresis suggests that system history is a factor that may increase the heterogeneity of NAPL source zones. PMID:18848369

Ryder, Jodi L; Demond, Avery H

2008-10-09

36

The Measurement of Wettability  

ERIC Educational Resources Information Center

|Discusses the use of a simple apparatus to measure contact angles between a liquid drop and a solid surface which are determining factors of wettability. Included are examples of applying this technique to various experimental situations. (CC)|

Pirie, Brian J. S.; Gregory, David W.

1973-01-01

37

Infiltration of PCE in a system containing spatial wettability variations  

Microsoft Academic Search

A two-dimensional infiltration experiment was conducted to investigate and quantify the effect of spatial wettability variations on DNAPL migration and entrapment in saturated sands. Experimental observations of tetrachloroethylene (PCE) infiltration showed that organic-wet sand lenses acted as very effective capillary barriers, retaining PCE and inhibiting its downward migration. A multiphase numerical simulator was used to model this sand box experiment.

Denis M. O'Carroll; Scott A. Bradford; Linda M. Abriola

2004-01-01

38

Drying patterns of porous media containing wettability contrasts.  

PubMed

Porous media containing sharp wettability discontinuities may occur in natural systems due to depositional processes, accumulation of organic layers or modification of soil wettability following intense forest fires all of which are known to significantly modify water flow and transport processes. We studied evaporation from sand columns containing hydraulically-interacting domains with sharp wettability contrasts. We employed neutron transmission technique to map liquid phase dynamics during evaporation, and conducted laboratory experiments to evaluate evaporative fluxes affected by interactions across wettability contrast. We explained the preferential drying front displacement in the hydrophobic domain and the spatial extent of capillary flow supporting the vaporization plane using a physically-based model. The model provides description of observed liquid phase patterns and dynamics observed in neutron radiography measurements and evaporative fluxes from laboratory experiments. Our results provide new insights into evaporation induced capillary exchange and preferential liquid phase distribution during evaporation from hydraulically interacting vertical porous domains with differing wettability properties and offer opportunities for design of selectively drying of porous media in natural and engineered systems. PMID:23123032

Shokri, N; Or, D

2012-10-12

39

Wettability of Boron Carbide.  

National Technical Information Service (NTIS)

The work was presented at the conference, Advanced Joining Technologies from New Materials II, which was held in Cocoa Beach, USA, 2-4th of March. The conference proceedings will be published in 1994. The wettability of boron carbide has been examined by ...

T. Torvund O. M. Akselsen O. Grong J. H. Ulvensoen

1994-01-01

40

Hydraulic Property Alterations due to Wettability Induced Changes by Diesel Fuels  

NASA Astrophysics Data System (ADS)

The remediation of non-aqueous phase liquid (NAPL) contaminated sites is impeded due to subsurface complexities, including wettability. Wettability quantifies which of two immiscible fluids preferentially coats a solid. At most contaminated sites water-wetting conditions are typically assumed despite mounting evidence that is not always the case. In this study, wettability was examined for two NAPL samples of contrasting origin: a fresh and a field sample. Wettability was assessed through (i) cyclical, 'cumulative elapsed contact time' intrinsic contact angle measurements, (ii) interface jar tests, and (iii) cyclical, pseudo-static capillary pressure-saturation curves. The work as a whole demonstrated that while the fresh diesel sample was consistently water-wet, the field diesel sample exhibited repeatable cycles of wettability reversal between water drainage and imbibition. And while wettability hysteresis increased with contact time for the field diesel, the occurrence of wettability reversal at each change of saturation direction was independent of contact time. Such behavior is not easily assessed by standard wettability indices. Moreover, it contrasts with the permanent wettability alteration observed for complex organics (e.g., coal tar) observed in most studies. It is hypothesized that the cyclical wettability reversal is related to cyclical changes in intermediate pore wettability due to sorption of surface active compounds (causing NAPL-wetting imbibition) and rupturing of the the soil grain water film (causing water-wet drainage). The wettability differences between the two NAPLs may be due to additives (i.e., a surfactant) in the original formulation and/or byproducts from subsurface weathering. These results support better characterization of site-specific wettability, improved model development and more realistic site conceptual models for improved remediation efforts.

O'Carroll, Denis

2013-04-01

41

Modeling Wettability Alteration using Chemical EOR Processes in Naturally Fractured Reservoirs  

SciTech Connect

The objective of our search is to develop a mechanistic simulation tool by adapting UTCHEM to model the wettability alteration in both conventional and naturally fractured reservoirs. This will be a unique simulator that can model surfactant floods in naturally fractured reservoir with coupling of wettability effects on relative permeabilities, capillary pressure, and capillary desaturation curves. The capability of wettability alteration will help us and others to better understand and predict the oil recovery mechanisms as a function of wettability in naturally fractured reservoirs. The lack of a reliable simulator for wettability alteration means that either the concept that has already been proven to be effective in the laboratory scale may never be applied commercially to increase oil production or the process must be tested in the field by trial and error and at large expense in time and money. The objective of Task 1 is to perform a literature survey to compile published data on relative permeability, capillary pressure, dispersion, interfacial tension, and capillary desaturation curve as a function of wettability to aid in the development of petrophysical property models as a function of wettability. The new models and correlations will be tested against published data. The models will then be implemented in the compositional chemical flooding reservoir simulator, UTCHEM. The objective of Task 2 is to understand the mechanisms and develop a correlation for the degree of wettability alteration based on published data. The objective of Task 3 is to validate the models and implementation against published data and to perform 3-D field-scale simulations to evaluate the impact of uncertainties in the fracture and matrix properties on surfactant alkaline and hot water floods.

Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

2007-09-30

42

Capillary Action may act as a cooling method in Plants and Animals  

NASA Astrophysics Data System (ADS)

A capillary tube in a plant may lead from its roots to the leaves. It takes no work for the column of water to rise from the roots to the leaves, and if there is capillarity in the soil, it takes no work for the water to flow through the ground to the roots. It does take work for a molecule of water to evaporate from the tube into the atmosphere. When a molecule of water evaporates another molecule travels through the soil and up the plant to replace it. The lost molecule creates a ``hole'' in the water column which like a signal is sent to the root and the sea of water in the soil replaces it. Since the water molecules are not unique this is the same situation as if the water vapor where condensed back to a liquid in a refrigeration cycle. Another interesting aspect of this sort of refrigeration is that the ``hole'' itself may be used to do work along the wall of the capillary tube, which may have Fermi Levels in it. An Hydraulic Semi Conductor, and in it is a method of cooling the Semi Conductor. This may be applicable to other similar systems using other liquids, or substances such as nanotube systems, where the hole signals,cools and performs chemical reactions involving not only obitals but Fermi Levels, a transition between Quantum and Classical Mechanics, with surprises.

Kriske, Richard

2012-02-01

43

Differential radial capillary action of ligand assay for high-throughput detection of protein-metabolite interactions  

PubMed Central

Interactions of proteins with low-molecular-weight ligands, such as metabolites, cofactors, and allosteric regulators, are important determinants of metabolism, gene regulation, and cellular homeostasis. Pharmaceuticals often target these interactions to interfere with regulatory pathways. We have developed a rapid, precise, and high-throughput method for quantitatively measuring protein-ligand interactions without the need to purify the protein when performed in cells with low background activity. This method, differential radial capillary action of ligand assay (DRaCALA), is based on the ability of dry nitrocellulose to separate the free ligand from bound protein–ligand complexes. Nitrocellulose sequesters proteins and bound ligand at the site of application, whereas free ligand is mobilized by bulk movement of the solvent through capillary action. We show here that DRaCALA allows detection of specific interactions between three nucleotides and their cognate binding proteins. DRaCALA allows quantitative measurement of the dissociation constant and the dissociation rate. Furthermore, DRaCALA can detect the expression of a cyclic-di-GMP (cdiGMP)-binding protein in whole-cell lysates of Escherichia coli, demonstrating the power of the method to bypass the prerequisite for protein purification. We have used DRaCALA to investigate cdiGMP signaling in 54 bacterial species from 37 genera and 7 eukaryotic species. These studies revealed the presence of potential cdiGMP-binding proteins in 21 species of bacteria, including 4 unsequenced species. The ease of obtaining metabolite-protein interaction data using the DRaCALA assay will facilitate rapid identification of protein-metabolite and protein-pharmaceutical interactions in a systematic and comprehensive approach.

Roelofs, Kevin G.; Wang, Jingxin; Sintim, Herman O.; Lee, Vincent T.

2011-01-01

44

Wettability Modification of Nanomaterials by Low-Energy Electron Flux  

PubMed Central

Controllable modification of surface free energy and related properties (wettability, hygroscopicity, agglomeration, etc.) of powders allows both understanding of fine physical mechanism acting on nanoparticle surfaces and improvement of their key characteristics in a number of nanotechnology applications. In this work, we report on the method we developed for electron-induced surface energy and modification of basic, related properties of powders of quite different physical origins such as diamond and ZnO. The applied technique has afforded gradual tuning of the surface free energy, resulting in a wide range of wettability modulation. In ZnO nanomaterial, the wettability has been strongly modified, while for the diamond particles identical electron treatment leads to a weak variation of the same property. Detailed investigation into electron-modified wettability properties has been performed by the use of capillary rise method using a few probing liquids. Basic thermodynamic approaches have been applied to calculations of components of solid–liquid interaction energy. We show that defect-free, low-energy electron treatment technique strongly varies elementary interface interactions and may be used for the development of new technology in the field of nanomaterials.

2009-01-01

45

Wettability control and patterning of PDMS using UV-ozone and water immersion.  

PubMed

We demonstrate a simple method to tune and pattern the wettability of polydimethylsiloxane (PDMS) to generate microfluidic mimics of heterogeneous porous media. This technique allows one to tailor the capillary forces at different regions within the PDMS channel to mimic multi-phase flow in oil reservoirs. In this method, UV-ozone treatment is utilized to oxidize and hydrophilize the surface of PDMS. To maintain a stable surface wettability, the oxidized surfaces are immersed in water. Additionally, the use of a photomask makes it convenient to pattern the wettability in the porous media. A one-dimensional diffusive reaction model is established to understand the UV-ozone oxidation as well as hydrophobic recovery of oxidized PDMS surfaces. The modeling results show that during UV-ozone, surface oxidation dominates over diffusion of low-molecular-weight (LMW) species. However, the diffusivity of LMW species plays an important role in wettability control of PDMS surfaces. PMID:21840014

Ma, Kun; Rivera, Javier; Hirasaki, George J; Biswal, Sibani Lisa

2011-07-21

46

Asphaltenes from Coal Tar and Creosote: Their Role in Reversing the Wettability of Aquifer Systems  

Microsoft Academic Search

The wettability of a subsurface system contaminated by coal tar or creosote is a major determinant of the capillary forces and, hence, the distribution and recoverability of these contaminants. The objective of this paper was to identify mechanisms that control the wetting characteristics of coal tar and creosote in the subsurface. Asphaltenes separated from these nonaqueous phase liquids were mixed

Jianzhong Zheng; Jiahui Shao; Susan E. Powers

2001-01-01

47

Effects of wetting agents on water infiltration into poorly wettable sand, dry sod and wettable soils  

Microsoft Academic Search

Six commercial wetting agents (three nonionic and three anionic compounds) were tested for their effects on water infiltration into poorly wettable sand, a layer of dry bermudagrass sod, and two wettable soils. The poorly wettable sand and the sod of dormant bermudagrass were obtained from an old lawn area, and the wettable soils (silty clay, and saline sodic silty clay

S. Miyamoto

1985-01-01

48

Bioinspired Surfaces with Special Wettability  

Microsoft Academic Search

ABSTRACT Biomimetic,research,indicates,that many,phenomena,regarding wettability in nature, such as the self-cleaning effect on a lotus leaf and cicada wing, the anisotropic dewetting behavior on a rice leaf, and striking superhydrophobic,force provided,by a water strider’s leg, are all related to the unique micro- and nanostructures on the surfaces. It gives us much,inspiration to realize special wettability on,functional,surfaces,through,the cooperation,between,the chemical composition and the

Taolei Sun; Lin Feng; Xuefeng Gao; Lei Jiang

2005-01-01

49

Electron-induced wettability modification  

Microsoft Academic Search

The pioneering works by Lippmann [Ann. Chim. Phys. 5, 494 (1875)] and Frumkin [Actual. Sci. Ind. 373, 5 (1936)] reported on electrowetting phenomenon. It was shown that electric potential, applied to an interface between a conducting liquid droplet and solid surface, strengthened the wetting effect. Here, we describe pronounced decrease of wettability induced by a low-energy electron irradiation. We observe

Daniel Aronov; Michel Molotskii; Gil Rosenman

2007-01-01

50

Mechanistic study of wettability alteration using surfactants with applications in naturally fractured reservoirs.  

PubMed

In naturally fractured reservoirs, oil recovery from waterflooding relies on the spontaneous imbibition of water to expel oil from the matrix into the fracture system. The spontaneous imbibition process is most efficient in strongly water-wet rock where the capillary driving force is strong. In oil- or mixed-wet fractured carbonate reservoirs, however, the capillary driving force for the spontaneous imbibition process is weak, and therefore the waterflooding oil recoveries are low. The recovery efficiency can be improved by dissolving low concentrations of surfactants in the injected water to alter the wettability of the reservoir rock to a more water-wet state. This wettability alteration accelerates the spontaneous imbibition of water into matrix blocks, thereby increasing the oil recovery during waterflooding. Several mechanisms have been proposed to explain the wettability alteration by surfactants, but none have been verified experimentally. Understanding of the mechanisms behind wettability alteration could help to improve the performance of the process and aid in identification of alternative surfactants for use in field applications. Results from this study revealed that ion-pair formation and adsorption of surfactant molecules through interactions with the adsorbed crude oil components on the rock surface are the two main mechanisms responsible for the wettability alteration. Previous researchers observed that, for a given rock type, the effectiveness of wettability alteration is highly dependent upon the ionic nature of the surfactant involved. Our experimental results demonstrated that ion-pair formation between the charged head groups of surfactant molecules and the adsorbed crude oil components on rock surface was more effective in changing the rock wettability toward a more water-wet state than the adsorption of surfactant molecules as a monolayer on the rock surface through hydrophobic interaction with the adsorbed crude oil components. By comparing two anionic surfactants with different charge densities, we propose that wettability alteration processes might be improved through the use of dimeric surfactants, which have two charged head groups and two hydrophobic tails. Gemini surfactants where the molecules are joined at the head end are likely to be effective when ion-pair formation is the wettability alteration mechanism, and bolaform surfactants, in which molecules are joined by the hydrophobic tails, should be more effective in the case of surfactant monolayer adsorption. PMID:19053658

Salehi, Mehdi; Johnson, Stephen J; Liang, Jenn-Tai

2008-12-16

51

A pore-level scenario for the development of mixed-wettability in oil reservoirs  

SciTech Connect

Understanding the role of thin films in porous media is vital if wettability is to be elucidated at the pore level. The type and thickness of films coating pore walls determines reservoir wettability and whether or not reservoir rock can be altered from its initial state of wettability. Pore shape, especially pore wall curvature, is an important factor in determining wetting-film thicknesses. Yet, pore shape and the physics of thin wetting films are generally neglected in models of flow in porous rocks. This paper incorporates thin-film forces into a collection of star-shaped capillary tubes model to describe the geological development of mixed-wettability in reservoir rock. Here, mixed-wettability refers to continuous and distinct oil and water-wetting surfaces coexisting in the porous medium. The proposed model emphasizes the remarkable role of thin films. New pore-level fluid configurations arise that are quite unexpected. For example, efficient water displacement of oil (i.e, low residual oil saturation) characteristic of mixed-wettability porous media is ascribed to interconnected oil lenses or rivulets which bridge the walls adjacent to a pore corner. Predicted residual oil saturations are approximately 35 % less in mixed-wet rock compared to completely water-wet rock. Calculated capillary pressure curves mimic those of mixed-wet porous media in the primary drainage of water, imbibition of water, and secondary drainage modes. Amott-Harvey indices range from {minus}0.18 to 0.36 also in good agreement with experimental values. (Morrow et al, 1986; Judhunandan and Morrow, 1991).

Kovscek, A.R.; Wong, H.; Radke, C.J.

1992-09-01

52

Electron-induced wettability modification  

SciTech Connect

The pioneering works by Lippmann [Ann. Chim. Phys. 5, 494 (1875)] and Frumkin [Actual. Sci. Ind. 373, 5 (1936)] reported on electrowetting phenomenon. It was shown that electric potential, applied to an interface between a conducting liquid droplet and solid surface, strengthened the wetting effect. Here, we describe pronounced decrease of wettability induced by a low-energy electron irradiation. We observe this effect in many materials of different origins. The proposed theory of this phenomenon explains the found growth of the hydrophobicity under an electron irradiation by decreasing solid/liquid and solid/vapor interfacial free energies, when reduction of the latter is always higher. This theory considers the droplet shape dependence on the incident electron charge density and energy of the incident electrons, as well as on the liquid and solid origins. The results of calculations are in a good agreement with the experimental data obtained for water droplet on amorphous silicon dioxide. The effect of the decrease of the wettability, induced by an electron irradiation at low incident charge, is completely reversible after subjection of the electron-irradiated material to ultraviolet illumination, which restores its initial wettability state.

Aronov, Daniel; Molotskii, Michel; Rosenman, Gil [Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Tel Aviv 69978 (Israel)

2007-07-15

53

Charge-induced wettability modification  

SciTech Connect

Electric charges deposited on a liquid droplet, located on a solid surface, strengthen the wetting effect. Here, the authors report on the opposite phenomenon--a decrease of wettability induced by a low-energy electron irradiation of solids. They provide evidence that the electron-induced surface charge decreases solid/liquid and solid/vapor interfacial energies when reduction of the latter is always higher. This explains the observed dependence of the droplet shape on the incident electron charge and energy, as well as on a liquid origin. This phenomenon is reversible when the charged material is subjected to ultraviolet illumination, which restores its initial state.

Aronov, D.; Molotskii, M.; Rosenman, G. [Department of Physical Electronics, School of Electrical Engineering, Tel-Aviv University, Tel-Aviv 69978 (Israel)

2007-03-05

54

Wettability and Its Effect on Oil Recovery  

Microsoft Academic Search

Reservoir wettability is determined by complex interface boundary conditions acting within the pore space of sedimentary rocks. These conditions have a dominant effect on interface movement and associated oil displacement. Wettability is a significant issue in multiphase flow problems ranging from oil migration from source rocks to such enhanced recovery processes as alkaline flooding or alternate injection of COâ and

Norman Morrow

1990-01-01

55

Wettability Literature Survey Part 5: The Effects of Wettability on Relative Permeability  

Microsoft Academic Search

The wettability of a core will strongly affect its waterflood behavior and relative permeability. Wettability affects relative permeability because it is a major factor in the control of the location, flow, and distribution of fluids in a porous medium. In uniformly or fractionally wetted porous media, the water relative permeability increases and the oil relative permeability decreases as the system

William Anderson

1987-01-01

56

Wettability Literature Survey-Part 6: The Effects of Wettability on Waterflooding  

Microsoft Academic Search

The wettability of a core will strongly affect its waterflood behavior and relative permeability because wettability is a major factor controlling the location, flow, and distribution of fluids in a porous medium. When a strongly water-wet system is waterflooded, recovery at water breakthrough is high, with little additional oil production after breakthrough. Conversely, water breakthrough occurs much earlier in strongly

W. G. Anderson

1987-01-01

57

Wettability modification of rock cores by fluorinated copolymer emulsion for the enhancement of gas and oil recovery  

NASA Astrophysics Data System (ADS)

The fluorine-containing acrylate copolymer emulsion was prepared with butyl acrylate, methacrylic acid and 1H, 1H, 2H, 2H-perfluorooctyl acrylate as monomers. Moreover, the structure of the copolymer was verified by Fourier transform infrared (FTIR), nuclear magnetic resonance (1H NMR and 19F NMR) and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that all the monomers had been copolymerized and the presence of fluorine moieties. The contact angle (CA) analyses, capillary rise and imbibition spontaneous tests were used to estimate the influence of the copolymer emulsion on the wettability of gas reservoirs. It was observed that the rock surface was of large contact angles of water, oilfield sewage, hexadecane and crude oil after treatment with the emulsion. The capillary rise results indicated that the contact angles of water/air and oil/air systems increased from 60° and 32° to 121° and 80°, respectively, due to the emulsion treatment. Similarly, because of wettability alteration by the fluoropolymer, the imbibition of water and oil in rock core decreased significantly. Experimental results demonstrated that the copolymer emulsion can alter the wettability of porous media from strong liquid-wetting to gas-wetting. This work provides a cost-effective method to prepare the fluoropolymer which can increase gas deliverability by altering the wettability of gas-condensate reservoirs and mitigating the water block effect.

Feng, Chunyan; Kong, Ying; Jiang, Guancheng; Yang, Jinrong; Pu, Chunsheng; Zhang, Yuzhong

2012-07-01

58

Nanofluid Surface Wettability Through Asymptotic Contact Angle.  

PubMed

This investigation introduces the asymptotic contact angle as a criterion to quantify the surface wettability of nanofluids and determines the variation of solid surface tensions with nanofluid concentration and nanoparticle size. The asymptotic contact angle, which is only a function of gas-liquid-solid physical properties, is independent of droplet size for ideal surfaces and can be obtained by equating the normal component of interfacial force on an axisymmetric droplet to that of a spherical droplet. The technique is illustrated for a series of bismuth telluride nanofluids where the variation of surface wettability is measured and evaluated by asymptotic contact angles as a function of nanoparticle size, concentration, and substrate material. It is found that the variation of nanofluid concentration, nanoparticle size, and substrate modifies both the gas-liquid and solid surface tensions, which consequently affects the force balance at the triple line, the contact angle, and surface wettability. PMID:21338112

Vafaei, Saeid; Wen, Dongsheng; Borca-Tasciuc, Theodorian

2011-02-21

59

Bioinspired colloidal photonic crystals with controllable wettability.  

PubMed

Because of the combinatorial advantage of their unique light manipulation properties and potential applications in novel optical devices, colloidal photonic crystals (PCs), the periodic arrangement of monodispersed latex spheres, have attracted interest from researchers. In particular, colloidal PCs exhibit structural colors based on interference effects within their periodic structures. The wavelength of these colors lies in the visible range, making them particularly attractive for a variety of applications. Colloidal PCs are extensively used in templating, catalysis, and chromatographic separations. Inspired by biological PCs with both structural color and specific wettability, researchers have fabricated colloidal PCs with controllable wettability as described in this Account. The wettability can be adjusted by the intrinsic roughness of colloidal crystals in combination with the tunable chemical composition of latex surfaces. Changes in the chemical composition of the latex surface under external stimuli, such as light, electricity, and heat, can reversibly control the wettability of PCs. Furthermore, the hierarchical structure of latex particles can effectively alter the water adhesive force of superhydrophobic colloidal PCs. Patterned PCs with a variety of wettabilities can be assembled using inkjet printing from well-designed latex suspensions. By combining their structural color and specific wettability, we also exemplify some of the promising applications of colloidal PCs as templates for the construction of hierarchical structures, as indicators for controllable transport of liquid droplets, and as color-based sensors for the monitoring changes in their environment. These findings offer innovative insights into the design of novel colloidal PCs and will be of great importance for further applications of these materials. PMID:21401081

Wang, Jingxia; Zhang, Youzhuan; Wang, Shutao; Song, Yanlin; Jiang, Lei

2011-03-14

60

Wettability and silicone hydrogel lenses: a review.  

PubMed

One of the major breakthroughs in the development of silicone hydrogel contact lenses has related to the ability of manufacturers to overcome the surface hydrophobicity that occurred with silicone elastomer lenses. However, the wettability of silicone hydrogel lenses continues to be of interest as a potential link between in vivo lens performance and contact lens-related comfort. This article will review some of the knowledge we have gained in the area of contact lens wettability over the past decade and will discuss some of the challenges related to its measurement. PMID:23274760

Keir, Nancy; Jones, Lyndon

2013-01-01

61

Tunable hydroxyapatite wettability: Effect on adhesion of biological molecules  

Microsoft Academic Search

Surface wettability modifications of biocompatible materials and wettability patterning are attractive methods for directed biological cells immobilization for tissue engineering, drug delivery, gene transfer, etc. Hydroxyapatite is known as an implantable biomimetic material and a substrate for effective adhesion of biological cells of various origins. Here we report the use of a low-energy electron irradiation to achieve tunable wettability of

D. Aronov; R. Rosen; E. Z. Ron; G. Rosenman

2006-01-01

62

Flow behaviour in the presence of wettability heterogeneities  

Microsoft Academic Search

The physical processes occurring during fluid flow and displacement within porous media having wettability heterogeneities have been investigated in specially designed heterogeneous visual models. The models were packed with glass beads, areas of which were treated with a water repellent to create wettability variations. Immiscible displacement experiments show visually the effect of wettability heterogeneities on the formation of residual oil

Albert Caruana; Richard A. Dawe

1996-01-01

63

Wettability of porous polydimethylsiloxane surface: morphology study  

Microsoft Academic Search

Two methods used for producing porous polydimethylsiloxane (PDMS) surfaces. In the first method, PDMS films without photosensitizer was exposed to CO2-pulsed laser at room temperature, as the excitation source. In the second method applying NaCl solid particles to the external surface layer before it is cured. In this study the morphology, wettability and surface chemical characteristics have been investigated. These

M. T. Khorasani; H. Mirzadeh; Z. Kermani

2005-01-01

64

Wettability changes induced by adsorption of asphaltenes  

SciTech Connect

Asphaltene fractions were precipitated from two crude oils (designated as Prudhoe Bay `95 and Wyoming `95) by addition of n-hexane. A solution of 250 mg/L of asphaltenes in toluene was used to induce wettability changes in Berea sandstone cores by flow of asphaltene solutions through the core. Concentration of asphaltenes in the effluent was measured by ultraviolet (UV) absorbance. Wettability changes were assessed from measurements of the rate of spontaneous imbibition for changes in initial water saturation and brine composition. Water wetness decreased markedly with increase in ionic strength, increase in cation valency, and decrease in initial water saturation. For comparable conditions, changing the brine anions (chloride, nitrate, carbonate, and sulfate) caused lesser but fairly consistent changes in wetting. Wetting changes induced by asphaltenes from the Wyoming `95 crude oil were always higher than for those prepared from the Prudhoe Bay `95 crude oil. Waterflood recoveries for NaCl, CaCl{sub 2}, and AlCl{sub 3} brines (0.09 M) increased with decrease in water wetness, with recovery reaching a maximum at an Amott wettability index of about 0.2. This result agrees with results reported previously for wettability changes induced by adsorption from crude oil.

Yan, J.; Plancher, H.; Morrow, N.R. [Univ. of Wyoming, Laramie, WY (United States)

1997-11-01

65

Alkyl- and fluoroalkyltrialkoxysilanes for wettability modification  

NASA Astrophysics Data System (ADS)

Alkyl- and fluoroalkyltriethoxysilanes were investigated as potential surface modifiers. Many aspects concerning trialkoxysilanes were discussed, starting from hydrolysis of silanes in water solutions, the effect of this hydrolysis on the surface tension, wettability of the modified surface to the morphology of the modified surface.

Dopierala, Katarzyna; Maciejewski, Hieronim; Karasiewicz, Joanna; Prochaska, Krystyna

2013-10-01

66

Wettability assessment of finely divided solids  

Microsoft Academic Search

The wettability of finely divided solids (powders and agglomerates) plays an important role in a number of practical applications such as dissolution, dispersion, granulation, coating, drying, etc. However, the characterisation of this property for powder materials is not a trivial task and has motivated several investigators to develop a large variety of experimental methods to assess it through its inherent

Mariem Lazghab; Khashayar Saleh; Isabelle Pezron; Pierre Guigon; Ljepsa Komunjer

2005-01-01

67

Droplet motion in one-component fluids on solid substrates with wettability gradients  

NASA Astrophysics Data System (ADS)

Droplet motion on solid substrates has been widely studied not only because of its importance in fundamental research but also because of its promising potentials in droplet-based devices developed for various applications in chemistry, biology, and industry. In this paper, we investigate the motion of an evaporating droplet in one-component fluids on a solid substrate with a wettability gradient. As is well known, there are two major difficulties in the continuum description of fluid flows and heat fluxes near the contact line of droplets on solid substrates, namely, the hydrodynamic (stress) singularity and thermal singularity. To model the droplet motion, we use the dynamic van der Waals theory [Phys. Rev. EPRESCM1539-375510.1103/PhysRevE.75.036304 75, 036304 (2007)] for the hydrodynamic equations in the bulk region, supplemented with the boundary conditions at the fluid-solid interface. In this continuum hydrodynamic model, various physical processes involved in the droplet motion can be taken into account simultaneously, e.g., phase transitions (evaporation or condensation), capillary flows, fluid velocity slip, and substrate cooling or heating. Due to the use of the phase field method (diffuse interface method), the hydrodynamic and thermal singularities are resolved automatically. Furthermore, in the dynamic van der Waals theory, the evaporation or condensation rate at the liquid-gas interface is an outcome of the calculation rather than a prerequisite as in most of the other models proposed for evaporating droplets. Numerical results show that the droplet migrates in the direction of increasing wettability on the solid substrates. The migration velocity of the droplet is found to be proportional to the wettability gradients as predicted by Brochard [LangmuirLANGD50743-746310.1021/la00086a025 5, 432 (1989)]. The proportionality coefficient is found to be linearly dependent on the ratio of slip length to initial droplet radius. These results indicate that the steady migration of the droplets results from the balance between the (conservative) driving force due to the wettability gradient and the (dissipative) viscous drag force. In addition, we study the motion of droplets on cooled or heated solid substrates with wettability gradients. The fast temperature variations from the solid to the fluid can be accurately described in the present approach. It is observed that accompanying the droplet migration, the contact lines move through phase transition and boundary velocity slip with their relative contributions mostly determined by the slip length. The results presented in this paper may lead to a more complete understanding of the droplet motion driven by wettability gradients with a detailed picture of the fluid flows and phase transitions in the vicinity of the moving contact line.

Xu, Xinpeng; Qian, Tiezheng

2012-05-01

68

Effects of wettability on three-phase flow in porous media  

SciTech Connect

The authors study the effects of rock wettability on the flow of oil, water, and gas in hydrocarbon reservoirs. The three-phase fluid configurations and displacement processes in a pore of polygonal cross section are described. Initially water-filled, water-wet pores are invaded by oil, representing primary oil migration. Where oil directly contacts the solid surface, the surface will change its wettability. Water injection followed by gas injection for any possible combination of oil/water, gas/water, and gas/oil contact angles was considered. The authors find the capillary pressures for the different displacement processes and determine the circumstances under which the various fluid configurations are stable. Using empirical expressions for the phase conductances, three-phase relative permeabilities for a bundle of pores of different sizes with constant triangular cross sections were measured. For gas injection, they show that the oil remains connected in wetting layers down to low oil saturation with a characteristic layer drainage regime, which gives very high ultimate oil recoveries. The only exceptions are nonspreading oils in water-wet media and large gas/oil contact angles. The relative permeability of the phase of intermediate wettability depends on two saturations, while the relative permeabilities of the other phases are functions of their own saturation only. In water-wet media, oil is the intermediate-wet phase. In weakly oil-wet media, water is intermediate-wet. In strongly oil-wet media, gas is intermediate-wet. This finding contradicts the assumptions made in many empirical models that gas is always the most nonwetting phase and that its relative permeability depends only on the gas saturation. This work indicates appropriate functional dependencies for three-phase relative permeabilities, and represents a necessary first step toward the development of a predictive pore-scale model that accounts for the effects of wettability in three-phase flow.

Hui, M.H.; Blunt, M.J.

2000-04-27

69

Direct Assessment of Wood's Metal Wettability on Quartz  

NASA Astrophysics Data System (ADS)

A tensiometric method (Wilhelmy plate) is used to study Wood's metal dynamic wettability on specially prepared surfaces of quartz single crystals at low velocities of immersion (2 to 16 ?m/s). After correction for buoyancy, the force exerted on the plate by the molten metal is used to derive the unit work of wetting ? cos ? where ? is the Wood's metal surface tension and ? is the interfacial contact angle. Tests at different temperatures (85, 120 and 200°C) show that below 120°C, viscosity effects cannot be neglected. At an immersion/emersion rate of 2 ?m/s, ? cos ? is in the range 0.417-0.444 N/m at 120°C, and 0.432-0.458 N/m at 200°C. These figures allow the conversion of injection pressures into capillary diameters during Wood's metal injection tests. The method is promising since it may be used in porous materials to check the sensitivity of the unit work of wetting ? cos ? to parameters such as roughness and mineralogy, which are known to vary in a wide range within the pores and cracks of rocks.

Darot, M.; Reuschlé, T.

70

Bioinspired steel surfaces with extreme wettability contrast  

NASA Astrophysics Data System (ADS)

The exterior structures of natural organisms have continuously evolved by controlling wettability, such as the Namib Desert beetle, whose back has hydrophilic/hydrophobic contrast for water harvesting by mist condensation in dry desert environments, and some plant leaves that have hierarchical micro/nanostructures to collect or repel liquid water. In this work, we have provided a method for wettability contrast on alloy steels by both nano-flake or needle patterns and tuning of the surface energy. Steels were provided with hierarchical micro/nanostructures of Fe oxides by fluorination and by a subsequent catalytic reaction of fluorine ions on the steel surfaces in water. A hydrophobic material was deposited on the structured surfaces, rendering superhydrophobicity. Plasma oxidization induces the formation of superhydrophilic surfaces on selective regions surrounded by superhydrophobic surfaces. We show that wettability contrast surfaces align liquid water within patterned hydrophilic regions during the condensation process. Furthermore, this method could have a greater potential to align other liquids or living cells.The exterior structures of natural organisms have continuously evolved by controlling wettability, such as the Namib Desert beetle, whose back has hydrophilic/hydrophobic contrast for water harvesting by mist condensation in dry desert environments, and some plant leaves that have hierarchical micro/nanostructures to collect or repel liquid water. In this work, we have provided a method for wettability contrast on alloy steels by both nano-flake or needle patterns and tuning of the surface energy. Steels were provided with hierarchical micro/nanostructures of Fe oxides by fluorination and by a subsequent catalytic reaction of fluorine ions on the steel surfaces in water. A hydrophobic material was deposited on the structured surfaces, rendering superhydrophobicity. Plasma oxidization induces the formation of superhydrophilic surfaces on selective regions surrounded by superhydrophobic surfaces. We show that wettability contrast surfaces align liquid water within patterned hydrophilic regions during the condensation process. Furthermore, this method could have a greater potential to align other liquids or living cells. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11934j

Her, Eun Kyu; Ko, Tae-Jun; Lee, Kwang-Ryeol; Oh, Kyu Hwan; Moon, Myoung-Woon

2012-04-01

71

Dynamics of capillary infiltration of liquids into a highly aligned multi-walled carbon nanotube film  

PubMed Central

Summary The physical compatibility of a highly aligned carbon nanotube (HACNT) film with liquids was established using a fast and convenient experimental protocol. Two parameters were found to be decisive for the infiltration process. For a given density of nanotube packing, the thermodynamics of the infiltration process (wettability) were described by the contact angle between the nanotube wall and a liquid meniscus (?). Once the wettability criterion (? < 90°) was met, the HACNT film (of free volume equal to 91%) was penetrated gradually by the liquid in a rate that can be linearly correlated to dynamic viscosity of the liquid (?). The experimental results follow the classical theory of capillarity for a steady process (Lucas–Washburn law), where the nanoscale capillary force, here supported by gravity, is compensated by viscous drag. This most general theory of capillarity can be applied in a prediction of both wettability of HACNT films and the dynamics of capillary rise in the intertube space in various technological applications.

Walczak, Krzysztof Z; Koziol, Krzysztof K K

2011-01-01

72

Tunable wettability and rewritable wettability-gradient in self-cleaning composites containing nanoscale photocatalysts.  

PubMed

The photo induced properties of self-cleaning materials can be attributed to the synergy of two fundamental photochemical phenomena, oxidation-reduction reaction of adsorbed substances and photo induced superhydrophilicity, which occur on the surface of photo catalysts. The photo-induced properties make these materials able to mimic the tunable wettability of the Nepenthes-Rafflesiana leaf and tune their wettability while decomposing the air pollution. In this study the effects of UV radiation and dark storage on reversibility of the surface wettability in cement-based composites containing tin oxide nanoparticles, were investigated. In addition the self-cleaning properties of these composites were determined by measuring the decomposition of Methylene blue (MB). PMID:23755674

Moradpour, R; Nassaj, E Taheri; Tavassoli, S H; Parhizkar, T; Ghodsian, M

2013-03-01

73

Characterization and Alteration of Wettability States of Alaskan Reserviors to Improve Oil Recovery Efficiency (including the within-scope expansion based on Cyclic Water Injection - a pulsed waterflood for Enhanced Oil Recovery)  

Microsoft Academic Search

Numerous early reports on experimental works relating to the role of wettability in various aspects of oil recovery have been published. Early examples of laboratory waterfloods show oil recovery increasing with increasing water-wetness. This result is consistent with the intuitive notion that strong wetting preference of the rock for water and associated strong capillary-imbibition forces gives the most efficient oil

Abhijit Dandekar; Shirish Patil; Santanu Khataniar

2008-01-01

74

Wettability patterning of hydroxyapatite nanobioceramics induced by surface potential modification  

SciTech Connect

Hydroxyapatite is known as a substrate for effective adhesion of various biological cells and bacteria as well implantable biomimetic material replacing defective bone tissues. It is found that low energy electron irradiation induces its strong surface potential variation and gives rise to pronounced wettability modification. The found electron-modulation method of the hydroxyapatite wettability enables both wettability switching and its microscopic patterning, which may be used for fabrication of spatially arrayed hydroxyapatite for biological cells immobilization, gene transfer, etc.

Aronov, D.; Rosenman, G.; Karlov, A.; Shashkin, A. [School of Electrical Engineering, Department of Physical Electronics, Tel Aviv University, 69978 (Israel); Center for Orthopedic and Medical Material Sciences of the Siberian Branch of the Russian Academy of Medical Sciences, 634029 Tomsk (Russian Federation)

2006-04-17

75

Effect of oxidation-reduction condition on wettability alteration  

SciTech Connect

This paper presents results of a laboratory study exploring the effect of the oxidation-reduction (redox) condition on crude-oil adsorption on rock mineral surfaces and consequent wettability alteration. Experiments were performed by aging Berea outcrop and Loudon reservoir sandstones with crude oil under various redox conditions and water saturations. Wettability alterations after aging were evaluated by the US Bureau of Mines (USBM) method and by waterflood tests. The natural, oxidized Brea cores changed from strongly water-wet to mixed-wet conditions when aged at irreducible water saturation. Wettability alteration was greatly reduced when aging experiments were conducted under reduced conditions. The degree of wettability alteration depended on availability and redox state of iron on the mineral surfaces and also on aging time. The authors suggest two possible mechanisms to explain the role of iron in the wettability-alternation process. Wettability alteration in the water-wet Berea cores was insignificant when the cores were aged at residual oil saturation (ROS). Wettability alteration was also significant in the mixed-wettability Loudon reservoir cores, regardless of the water saturation or redox condition used in the aging experiments. The authors present the implications of these finding on core-handling procedures for wettability preservation.

Wang, F.H.L.; Guidry, L.J. (Exxon Production Research Co., Houston, TX (United States))

1994-06-01

76

Evaluating the Influence of Pore Architecture and Initial Saturation on Wettability and Relative Permeability in Heterogeneous, Shallow-Shelf Carbonates  

SciTech Connect

Thin (3-40 ft thick), heterogeneous, limestone and dolomite reservoirs, deposited in shallow-shelf environments, represent a significant fraction of the reservoirs in the U.S. midcontinent and worldwide. In Kansas, reservoirs of the Arbuckle, Mississippian, and Lansing-Kansas City formations account for over 73% of the 6.3 BBO cumulative oil produced over the last century. For these reservoirs basic petrophysical properties (e.g., porosity, absolute permeability, capillary pressure, residual oil saturation to waterflood, resistivity, and relative permeability) vary significantly horizontally, vertically, and with scale of measurement. Many of these reservoirs produce from structures of less than 30-60 ft, and being located in the capillary pressure transition zone, exhibit vertically variable initial saturations and relative permeability properties. Rather than being simpler to model because of their small size, these reservoirs challenge characterization and simulation methodology and illustrate issues that are less apparent in larger reservoirs where transition zone effects are minor and most of the reservoir is at saturations near S{sub wirr}. These issues are further augmented by the presence of variable moldic porosity and possible intermediate to mixed wettability and the influence of these on capillary pressure and relative permeability. Understanding how capillary-pressure properties change with rock lithology and, in turn, within transition zones, and how relative permeability and residual oil saturation to waterflood change through the transition zone is critical to successful reservoir management and as advanced waterflood and improved and enhanced recovery methods are planned and implemented. Major aspects of the proposed study involve a series of tasks to measure data to reveal the nature of how wettability and drainage and imbibition oil-water relative permeability change with pore architecture and initial water saturation. Focus is placed on carbonate reservoirs of widely varying moldic pore systems that represent the major of reservoirs in Kansas and are important nationally and worldwide. A goal of the project is to measure wettability, using representative oils from Kansas fields, on a wide range of moldic-porosity lithofacies that are representative of Kansas and midcontinent shallow-shelf carbonate reservoirs. This investigation will discern the relative influence of wetting and pore architecture. In the midcontinent, reservoir water saturations are frequently greater than 'irreducible' because many reservoirs are largely in the capillary transition zone. This can change the imbibition oil-water relative permeability relations. Ignoring wettability and transition-zone relative permeabilities in reservoir modeling can lead to over- and under-prediction of oil recovery and recovery rates, and less effective improved recovery management. A goal of this project is to measure drainage and imbibition oil-water relative permeabilities for a large representative range of lithofacies at differ ent initial water saturations to obtain relations that can be applied everywhere in the reservoir. The practical importance of these relative permeability and wettability models will be demonstrated by using reservoir simulation studies on theoretical/generic and actual reservoir architectures. The project further seeks to evaluate how input of these new models affects reservoir simulation results at varying scales. A principal goal is to obtain data that will allow us to create models that will show how to accurately simulate flow in the shallow-structure, complex carbonate reservoirs that lie in the transition zone. Tasks involved to meet the project objectives include collection and consolidation of available data into a publicly accessible relational digital database and collection of oil and rock samples from carbonate fields around the state (Task 1). Basic properties of these rocks and oils will be measured and used in wettability tests. Comparison will be performed between crude and synthetic oil wettability and

Alan P. Byrnes; Saibal Bhattacharya; John Victorine; Ken Stalder

2007-09-30

77

Wettability literature survey - Part 6: The effects of wettability on waterflooding  

SciTech Connect

The wettability of a core will strongly affect its waterflood behavior and relative permeability because wettability is a major factor controlling the location, flow, and distribution of fluids in a porous medium. When a strongly water-wet system is waterflooded, recovery at water breakthrough is high, with little additional oil production after breakthrough. Conversely, water breakthrough occurs much earlier in strongly oil-wet systems, with most of the oil recovered during a long period of simultaneous oil and water production. Waterfloods are less efficient in oil-wet systems compared with water-wet ones because more water must be injected to recover a given amount of oil. This paper examines the effects of wettability on waterflooding, including the effects on the breakthrough and residual oil saturations (ROS's) and the changes in waterflood behavior caused by core cleaning. Also covered are waterfloods in heterogeneously wetted systems. Waterfloods in fractionally wetted sandpacks, where the size of the individual water-wet and oil-wet surfaces are on the order of a single pore, behave like waterfloods in uniformly wetted systems. In a mixed-wettability system, the continuous oil-wet paths in the larger pores alter the relative permeability curves and allow the system to be waterflooded to a very low ROS after the injection of many PV's of water.

Anderson, W.G.

1987-12-01

78

The effect of wettability on drop attachment to glass rods  

Microsoft Academic Search

The coalescence of droplets in fibrous filters depends on many parameters such as wettability, filter depth, flow velocity, and filter materials. The objective of this work is to determine the effect of the wettability on the coalescence mechanism. Experimental results from tests on coated glass rods are presented. Three different silanes are deposited on the glass rod surfaces to change

C Shin; G. G Chase

2004-01-01

79

Plasma-treated switchable wettability of parylene-C surface  

Microsoft Academic Search

The wetting behavior of biomaterials is of great importance for the issues such as biofouling control and biocompatibility improvement. Therefore, tailoring of their wettability is particularly useful and has been attracting a lot of interests. This paper focuses on the modification of surface wettability on the parylene-C film, which is exclusively used as a coating material for insulating implantable biomedical

Xiao-Peng Bi; Nathan L. Ward; Brian P. Crum; Wen Li

2012-01-01

80

Wettability influences cell behavior on superhydrophobic surfaces with different topographies  

Microsoft Academic Search

Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavior on superhydrophobic surfaces is influenced by surface topography and polymer type. Biomimetic superhydrophobic rough surfaces of

B. N. Lourenco; G. Marchioli; W Song; R. L. Reis; Blitterswijk van C. A; H. B. J. Karperien; Apeldoorn van A. A; J. F. Mano

2012-01-01

81

Microbial enhanced oil recovery and wettability research program  

Microsoft Academic Search

This report covers research results for the microbial enhanced oil recovery (MEOR) and wettability research program conducted by EG G Idaho, Inc. at the Idaho National Engineering Laboratory (INEL). The isolation and characterization of microbial species collected from various locations including target oil field environments is underway to develop more effective oil recovery systems for specific applications. The wettability research

C. P. Thomas; G. A. Bala; M. L. Duvall

1991-01-01

82

Control over wettability via surface modification of porous gradients  

Microsoft Academic Search

The control over surface wettability is of concern for a number of important applications including chromatography, microfluidics, biomaterials, low-fouling coatings and sensing devices. Here, we report the ability to tailor wettability across a surface using lateral porous silicon (pSi) gradients. Lateral gradients made by anodisation of silicon using an asymmetric electrode configuration showed a lateral distribution of pore sizes, which

Y. L. Khung; M. A. Cole; S. J. P. McInnes; N. H. Voelcker

2007-01-01

83

The effects of fractional wettability on microbial enhanced oil recovery  

NASA Astrophysics Data System (ADS)

Microbial enhanced oil recovery (MEOR) is a tertiary oil recovery technology that has had inconsistent success at the field-scale, while lab-scale experiments are mostly successful. One potential reason for these inconsistencies is that the efficacy of MEOR in fractional-wet systems is unknown. Our MEOR strategy consists of the injection of ex situ produced metabolic byproducts produced by Bacillus mojavensis JF-2 (that lower interfacial tension via biosurfactant production) into fractional-wet cores containing residual oil. Fractional-wet cores tested were 50%, 25%, and 0% oil-wet and two different MEOR flooding solutions were tested; one solution contained both microbes and metabolic byproducts while the other contained only the metabolic byproducts. The columns were imaged with x-ray computed microtomography (CMT) after water flooding, and after MEOR, which allowed for the evaluation of the pore-scale processes taking place during MEOR and wettability effects. Results indicate that during MEOR the larger residual oil blobs in mostly fractional-wet pores and residual oil held under relatively low capillary pressures were the main fractions recovered, while residual oil blobs in purely oil-wet pores remained in place. Residual oil saturation, interfacial curvatures, and oil blob sizes were measured from the CMT images and used to develop a conceptual model for MEOR in fractional-wet systems. Overall, results indicate that MEOR was effective at recovering oil from fractional-wet systems with reported additional oil recovered (AOR) values between 44% and 80%; the highest AOR values were observed in the most oil-wet system.

Wildenschild, D.; Armstrong, R. T.

2011-12-01

84

Pool boiling of nanoparticle-modified surface with interlaced wettability  

NASA Astrophysics Data System (ADS)

This study investigated the pool boiling heat transfer under heating surfaces with various interlaced wettability. Nano-silica particles were used as the coating element to vary the interlaced wettability of the surface. The experimental results revealed that when the wettability of a surface is uniform, the critical heat flux increases with the more wettable surface; however, when the wettability of a surface is modified interlacedly, regardless of whether the modified region becomes more hydrophilic or hydrophobic, the critical heat flux is consistently higher than that of the isotropic surface. In addition, this study observed that critical heat flux was higher when the contact angle difference between the plain surface and the modified region was smaller.

Hsu, Chin-Chi; Su, Tsung-Wen; Chen, Ping-Hei

2012-05-01

85

Pool boiling of nanoparticle-modified surface with interlaced wettability  

PubMed Central

This study investigated the pool boiling heat transfer under heating surfaces with various interlaced wettability. Nano-silica particles were used as the coating element to vary the interlaced wettability of the surface. The experimental results revealed that when the wettability of a surface is uniform, the critical heat flux increases with the more wettable surface; however, when the wettability of a surface is modified interlacedly, regardless of whether the modified region becomes more hydrophilic or hydrophobic, the critical heat flux is consistently higher than that of the isotropic surface. In addition, this study observed that critical heat flux was higher when the contact angle difference between the plain surface and the modified region was smaller.

2012-01-01

86

Wettability control by DLC coated nanowire topography.  

PubMed

Here we have developed a convenient method to fabricate wettability controllable surfaces that can be applied to various nanostructured surfaces with complex shapes for different industrial needs. Diamond-like carbon (DLC) films were synthesized on titanium substrate with a nanowire structured surface using plasma immersion ion implantation and deposition (PIII&D). The nanostructure of the DLC films was characterized by field emission scanning electron microscopy and found to grow in a rippling layer-by-layer manner. Raman spectroscopy was used to investigate the different bonding presented in the DLC films. To determine the wettability of the samples, water contact angles were measured and found to vary in the range of 50°-141°. The results indicated that it was critical to construct a proper surface topography for high hydrophobicity, while suitable I(D)/I(G) and sp²/sp³ ratios of the DLC films had a minor contribution. Superhydrophobicity could be achieved by further CF? implantation on suitably structured DLC films and was attributed to the existence of fluorine. In order to maintain the nanostructure during CF? implantation, it was favorable to pre-deposit an appropriate carbon content on the nanostructure, as a nanostructure with low carbon content would be deformed during CF? implantation due to local accumulation of surface charge and the following discharge resulting from the low conductivity. PMID:21343636

Li, Zihui; Meng, Fanhao; Liu, Xuanyong

2011-02-22

87

Wettability control by DLC coated nanowire topography  

NASA Astrophysics Data System (ADS)

Here we have developed a convenient method to fabricate wettability controllable surfaces that can be applied to various nanostructured surfaces with complex shapes for different industrial needs. Diamond-like carbon (DLC) films were synthesized on titanium substrate with a nanowire structured surface using plasma immersion ion implantation and deposition (PIII&D). The nanostructure of the DLC films was characterized by field emission scanning electron microscopy and found to grow in a rippling layer-by-layer manner. Raman spectroscopy was used to investigate the different bonding presented in the DLC films. To determine the wettability of the samples, water contact angles were measured and found to vary in the range of 50°-141°. The results indicated that it was critical to construct a proper surface topography for high hydrophobicity, while suitable ID/IG and sp2/sp3 ratios of the DLC films had a minor contribution. Superhydrophobicity could be achieved by further CF4 implantation on suitably structured DLC films and was attributed to the existence of fluorine. In order to maintain the nanostructure during CF4 implantation, it was favorable to pre-deposit an appropriate carbon content on the nanostructure, as a nanostructure with low carbon content would be deformed during CF4 implantation due to local accumulation of surface charge and the following discharge resulting from the low conductivity.

Li, Zihui; Meng, Fanhao; Liu, Xuanyong

2011-04-01

88

A Disposable Optical Fiber-Based Capillary Probe for Sensing Lead Ions  

Microsoft Academic Search

A disposable capillary-based probe using optical fiber technology to create a compact and portable configuration has been designed for sensing lead ions. It is based around a glass capillary tube pretreated with a fluorophore with high sensitivity and selectivity towards lead ions. The capillary tube makes use of capillary action to uptake the same sample volume for each single-shot measurement.

Henri Guillemain; Muttukrishnan Rajarajan; Tong Sun; Kenneth T. V. Grattan; Yu-Chen Lin; Chao-Tsen Chen

2008-01-01

89

Wettability analysis of tin-based, lead free solders  

SciTech Connect

The overall program is comprised of two efforts. The first effort studies the wettability of tin-based, lead free solders on two commonly used substrate materials: copper and gold-nickel plated Kovar{trademark}. The evaluation is being conducted by the meniscometer/wetting balance technique which uses the contact angle as the primary metric to quantify wettability. Information about the rate of wetting is also obtainable with this test. The second part of the program is comprised of an assessment of the solderability of actual circuit board assemblies (surface mount and through-hole). This report will describe data from the wettability analysis of lead free solders on copper.

Vianco, P T; Hosking, F M; Rejent, J A

1992-01-01

90

Wettability Switching Techniques on Superhydrophobic Surfaces  

PubMed Central

The wetting properties of superhydrophobic surfaces have generated worldwide research interest. A water drop on these surfaces forms a nearly perfect spherical pearl. Superhydrophobic materials hold considerable promise for potential applications ranging from self cleaning surfaces, completely water impermeable textiles to low cost energy displacement of liquids in lab-on-chip devices. However, the dynamic modification of the liquid droplets behavior and in particular of their wetting properties on these surfaces is still a challenging issue. In this review, after a brief overview on superhydrophobic states definition, the techniques leading to the modification of wettability behavior on superhydrophobic surfaces under specific conditions: optical, magnetic, mechanical, chemical, thermal are discussed. Finally, a focus on electrowetting is made from historical phenomenon pointed out some decades ago on classical planar hydrophobic surfaces to recent breakthrough obtained on superhydrophobic surfaces.

2007-01-01

91

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces  

PubMed Central

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-01-01

92

Water transport mechanism through open capillaries analyzed by direct surface modifications on biological surfaces.  

PubMed

Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field. PMID:24149467

Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu

2013-10-23

93

Thermal Instability of Fats Relative to Surface Wettability of Yellow ...  

Treesearch

Title: Thermal Instability of Fats Relative to Surface Wettability of Yellow Birchwood ... were examined in an attempt to illustrate how heat-induced changes in wood fats ... to the wood was highly dependent upon heating temperature and time.

94

Wettability changes of TiO2 nanotube surfaces  

Microsoft Academic Search

This study examines the effect of environmental and experimental conditions, such as temperature and time, on the wettability properties of titania nanotube (TNT) surfaces fabricated by anodization. The fabricated TNTs are 60-130 nm inner diameter and 7-10 µm height. One-microliter water droplets were used to define the wettability of the TNT surfaces by measuring the contact angles. A digital image

Dong Hwan Shin; Tolou Shokuhfar; Chang Kyoung Choi; Seong-Hyuk Lee; Craig Friedrich

2011-01-01

95

Quantitative estimates of porous media wettability from proton NMR measurements.  

PubMed

Nuclear magnetic resonance (NMR) relaxation time distributions provide information on the abundance and distribution of two immiscible fluids in the pores of fine-grain chalk samples. A model based on relative shifts of the water-relaxation component as a function of saturation results in a wettability index that is strongly correlated with independent dynamic measurements of wettability. Scales of wetting-phase film thickness for NMR and dynamic measurements explain differences in results between the two methods. PMID:9803903

Howard, J J

96

Engineered antifouling microtopographies – correlating wettability with cell attachment  

Microsoft Academic Search

Bioadhesion and surface wettability are influenced by microscale topography. In the present study, engineered pillars, ridges and biomimetic topography inspired by the skin of fast moving sharks (Sharklet AF™) were replicated in polydimethylsiloxane elastomer. Sessile drop contact angle changes on the surfaces correlated well (R = 0.89) with Wenzel and Cassie and Baxter's relationships for wettability. Two separate biological responses, i.e. settlement

Michelle L. Carman; Thomas G. Estes; Adam W. Feinberg; James F. Schumacher; Wade Wilkerson; Leslie H. Wilson; Maureen E. Callow; James A. Callow; Anthony B. Brennan

2006-01-01

97

Capillary micro-switches  

Microsoft Academic Search

A capillary surface is a liquid\\/liquid or liquid\\/gas interface whose shape is determined by surface tension. Capillary surfaces occur when the capillary length is large compared to the container scale, as happens for typical liquids against gas on the sub-millimeter scale on Earth and on the meter scale in the micro-gravity environment of space vehicles. Manipulating capillary surfaces has emerged

Paul Steen; Claude Matalanis; Amir Hirsa; Christhopher Cox

2002-01-01

98

IMPACT OF CAPILLARY AND BOND NUMBERS ON RELATIVE PERMEABILITY  

SciTech Connect

Recovery and recovery rate of oil, gas and condensates depend crucially on their relative permeability. Relative permeability in turn depends on the pore structure, wettability and flooding conditions, which can be represented by a set of dimensionless groups including capillary and bond numbers. The effect of flooding conditions on drainage relative permeabilities is not well understood and is the overall goal of this project. This project has three specific objectives: to improve the centrifuge relative permeability method, to measure capillary and bond number effects experimentally, and to develop a pore network model for multiphase flows. A centrifuge has been built that can accommodate high pressure core holders and x-ray saturation monitoring. The centrifuge core holders can operate at a pore pressure of 6.9 MPa (1000 psi) and an overburden pressure of 17 MPa (2500 psi). The effect of capillary number on residual saturation and relative permeability in drainage flow has been measured. A pore network model has been developed to study the effect of capillary numbers and viscosity ratio on drainage relative permeability. Capillary and Reynolds number dependence of gas-condensate flow has been studied during well testing. A method has been developed to estimate relative permeability parameters from gas-condensate well test data.

Kishore K. Mohanty

2002-09-30

99

Fabrication of high wettability gradient on copper substrate  

NASA Astrophysics Data System (ADS)

Copper is one of the most widely used materials in condensation heat transfer. Recently there has been great interest in improving the condensation heat transfer efficiency through copper surface modification. In this study, we describe the fabrication processes of how copper surfaces were modified to be superhydrophilic (CA ? 10°) and superhydrophobic (CA > 150°) by means of H2O2 immersion and fluorination with Teflon. The wettability gradient of copper surfaces with contact angles (CA) changing from superhydrophilic to superhydrophobic are also demonstrated. Unlike previous studies on gradient surfaces in which the wettability gradient is controlled either non-precisely or entirely uncontrolled, in this study, the contact angles along wettability gradient copper surfaces vary with a precisely designed gradient. It is demonstrated that a high wettability gradient copper surface can be successfully fabricated using photolithography to define the area ratios between superhydrophilic and superhydrophobic patterns within a short distance. The fabricated wettability gradient of copper surfaces is expected to be able to enhance the condensation heat transfer efficiency.

Huang, Ding-Jun; Leu, Tzong-Shyng

2013-09-01

100

A Comparison of Splash Erosion Behavior between Wettable and Water Repellent 'Soil' Particles  

NASA Astrophysics Data System (ADS)

Wildfires remove vegetation and litter cover and expose soil surfaces to particle detachment by rain splash. This can serve as an agent of initial soil modification and erosion in the post-fire period. Splash behavior is mainly determined by the kinetic energy delivered by impacting water drops (erosivity), and the detachability (erodibility) of surface particles, affected by their size, aggregate stability and shear strength. Soil detachability may also be affected by water repellency (hydrophobicity). This soil characteristic is influenced by wildfire and may affect splash behavior by reducing capillary forces between particles. Previous work on splash behavior using cumulative drop impact reported larger ejection droplets and lower and shorter trajectories of ejections for water repellent soil compared with wettable soil (Terry and Shakesby 1993). A water film generated by delayed infiltration on water repellent soil was suggested to account for the difference. This study compares the trajectories of ejected wettable and hydrophobic model soil particles from single water drop impacts in order to isolate the effect of soil particle wettability on splash erosion behavior. Acid-washed (wettable) and hydrophobized (water repellent) glass beads used as model soil particles were held in an array within a squat cylinder of 1.5 cm diameter in the centre of a 20 cm diameter disk covered with a viscous adhesive film. A distilled water drop (20?L) was released 40 cm above the centre of the array and the resultant impact was recorded at 976 frames per second using a high speed video camera. The populations of, and distances travelled by, the particles were measured for three arrays of bead sizes within the range (180-400 ?m). Three to five replications were made for each test. The trajectory of each ejected particle was traced on video frames and corrected for the actual distance and direction of travel measured from the adhesive film. The initial velocity and ejecting angle of individual particles were calculated from the equation of motion, ignoring the air resistance and in-flight evaporation. In contrast to Terry and Shakesby (1993), we observed that a single drop impact resulted mainly in dispersion (splash saltation) with few ejections of particles entrained by a water droplet (splashing), and the trajectories of ejections from water repellent particle arrays were higher than those from the hydrophilic arrays. These higher trajectories were driven by higher initial velocity for the water repellent particles, despite lower ejecting angles. This result suggests that water repellent soil is more vulnerable to initial splash detachment before a water film is generated by accumulation of rain drops. The distributions of initial velocity and ejecting angle of all particles are compared between wettable and water repellent particles and discussed in detail in this contribution. Terry JP and Shakesby RA, 1993. Earth Surface Processes and Landforms 18: 519-525. Acknowledgement: This study has been funded by Engineering and Physical Sciences Research Council of United Kingdom.

Ahn, S.; Hamlett, C. A.; Doerr, S.; Bryant, R.; Shirtcliffe, N.; McHale, G.; Newton, M.

2011-12-01

101

Engineered antifouling microtopographies--correlating wettability with cell attachment.  

PubMed

Bioadhesion and surface wettability are influenced by microscale topography. In the present study, engineered pillars, ridges and biomimetic topography inspired by the skin of fast moving sharks (Sharklet AF) were replicated in polydimethylsiloxane elastomer. Sessile drop contact angle changes on the surfaces correlated well (R2 = 0.89) with Wenzel and Cassie and Baxter's relationships for wettability. Two separate biological responses, i.e. settlement of Ulva linza zoospores and alignment of porcine cardiovascular endothelial cells, were inversely proportional to the width (between 5 and 20 microm) of the engineered channels. Zoospore settlement was reduced by approximately 85% on the finer (ca 2 microm) and more complex Sharklet AF topographies. The response of both cell types suggests their responses are governed by the same underlying thermodynamic principles as wettability. PMID:16551557

Carman, Michelle L; Estes, Thomas G; Feinberg, Adam W; Schumacher, James F; Wilkerson, Wade; Wilson, Leslie H; Callow, Maureen E; Callow, James A; Brennan, Anthony B

2006-01-01

102

Wettability and fluid saturations determined from NMR T1 distributions.  

PubMed

The abundance and distribution of brine and decane are determined from T1 distributions at different stages of a water-flood test in water-wet and oil-wet chalks. The T1 distributions generated from multi-exponential decomposition of inversion-recovery data provide more information than obtained from stretched and bi-exponential fits. Chalk samples because of their uniform pore size and ideal sedimentary rocks for NMR investigations of wettability since water and decane interactions with pore walls of differing wettability are easily distinguished. PMID:8170297

Howard, J J

1994-01-01

103

Moisture and aging effects of solder wettability of copper surfaces  

SciTech Connect

Solderability is a critical property of electronic assembly that affects both manufacturing efficiency and product reliability. There is often a considerable time interval between initial fabrication of a circuit board or component and its use at the assembly level. Parts are often stored under a variety of conditions, usually not controlled. Solder wettability can soon deteriorate during storage, especially in extreme environments. This paper describes ongoing efforts at Sandia to quantify solder wettability on bare and aged Cu surfaces. In addition, organic solderability preservatives (OSPs) were applied to the bare Cu to retard solderability loss due to aging. The OSPs generally performed well, although wetting did decrease with exposure time.

Hernandez, C.L.; Sorensen, N.R.; Lucero, S.J.

1996-12-01

104

Fabrication of superhydrophobic polyaniline films with rapidly switchable wettability  

NASA Astrophysics Data System (ADS)

A superhydrophobic polyaniline (PANI) film has been fabricated by using a facile one-step spraying method. The PANI was synthesized via in situ doping polymerization in the presence of perfluorooctanoic acid (PFOA) as the dopant. The water contact angle of this superhydrophobic surface reaches to 156°. Both the surface chemical compositions and morphological structures were analyzed. A granular morphology of PANI with a moderate amount of nanofibers was obtained. Moreover, a rapid surface wettability transition between superhydrophobicity and superhydrophilicity can be observed when it is doped with PFOA and de-doped with base. The mechanism for this tunable wettability has been discussed in detail.

Zhou, Xiaoyan; Zhang, Zhaozhu; Men, Xuehu; Yang, Jin; Xu, Xianghui; Zhu, Xiaotao; Xue, Qunji

2011-10-01

105

An investigation of the effect of wettability on NMR characteristics of sandstone rock and fluid systems  

Microsoft Academic Search

Predicting reservoir wettability and its effect on fluid distribution and hydrocarbon recovery remains one of the major challenges in reservoir evaluation and engineering. Current laboratory based techniques require the use of rock–fluid systems that are representative of in situ reservoir wettability and preferably under reservoir conditions of pressure and temperature. However, the estimation of reservoir wettability is difficult to obtain

S. H. Al-Mahrooqi; C. A. Grattoni; A. K. Moss; X. D. Jing

2003-01-01

106

Effect of Wettability on Waterflood Recovery for Crude-Oil\\/Brine\\/Rock Systems  

Microsoft Academic Search

This paper presents a definitive account of the effect of wettability on oil recovery from Berea sandstone based on the results of more than 50 slow-rate laboratory waterfloods. Closely reproducible wettability conditions and waterflood recoveries were obtained with wettability, depending on the crude oil, brine composition, aging temperature, and initial water saturation. Maximum oil recovery by waterflooding was obtained at

P. P. Jadhunandan; N. R. Morrow

1995-01-01

107

A pore-level scenario for the development of mixed wettability in oil reservoirs  

Microsoft Academic Search

Understanding the role of thin films in porous media is vital to elucidate wettability at the pore level. The type and thickness of films coating pore walls determine reservoir wettability and whether or not reservoir rock can be altered from its initial state of wettability. Pore shape, especially pore wall curvature, is important in determining wetting-film thicknesses. Yet, pore shape

A. R. Kovscek; H. Wong; C. J. Radke

1993-01-01

108

Wettability of reservoir rock and fluid systems from complex resistivity measurements  

Microsoft Academic Search

Electrical resistivity measurements at a single low AC frequency have long been recognized as providing an indication of the wettability of reservoir rock and fluid systems. However, the resistivity response over a range of frequencies for samples of varying wettability is not so well characterized. Data is presented from reservoir core plugs of differing lithologies, permeabilities, and wettabilities. The complex

A. K Moss; X. D Jing; J. S Archer

2002-01-01

109

Wettability of Oil-Producing Reservoir Rocks as Determined from X-ray Photoelectron Spectroscopy  

Microsoft Academic Search

Wettability has a dominant effect in oil recovery by waterflooding and in many other processes of industrial and environmental interest. Recently, the suggestion has been made that surface science analytical techniques (SSAT) could be used to rapidly determine the wettability of reservoir materials. Here, we bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of

Pedro G. Toledo; Y. Carolina Araujo; Vladimir Leon

1996-01-01

110

Spontaneous imbibition for mixed-wettability states in sandstones induced by adsorption from crude oil  

Microsoft Academic Search

Wettability control by methods that are of practical relevance to oil recovery is an ongoing problem in wettability research. The preparation of mixed-wettability cores by adsorption from an asphaltic crude oil at elevated temperature and pressure has been investigated. After aging, crude oil was displaced by flow of decalin, an intermediate solvent that was compatible with the crude oil with

Z. X. Tong; N. R. Morrow; X. Xie

2003-01-01

111

Multiple capillary biochemical analyzer  

DOEpatents

A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibres to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands.

Dovichi, Norman J. (Edmonton, CA); Zhang, Jian Z. (Edmonton, CA)

1995-01-01

112

Multiple capillary biochemical analyzer  

DOEpatents

A multiple capillary analyzer allows detection of light from multiple capillaries with a reduced number of interfaces through which light must pass in detecting light emitted from a sample being analyzed, using a modified sheath flow cuvette. A linear or rectangular array of capillaries is introduced into a rectangular flow chamber. Sheath fluid draws individual sample streams through the cuvette. The capillaries are closely and evenly spaced and held by a transparent retainer in a fixed position in relation to an optical detection system. Collimated sample excitation radiation is applied simultaneously across the ends of the capillaries in the retainer. Light emitted from the excited sample is detected by the optical detection system. The retainer is provided by a transparent chamber having inward slanting end walls. The capillaries are wedged into the chamber. One sideways dimension of the chamber is equal to the diameter of the capillaries and one end to end dimension varies from, at the top of the chamber, slightly greater than the sum of the diameters of the capillaries to, at the bottom of the chamber, slightly smaller than the sum of the diameters of the capillaries. The optical system utilizes optic fibers to deliver light to individual photodetectors, one for each capillary tube. A filter or wavelength division demultiplexer may be used for isolating fluorescence at particular bands. 21 figs.

Dovichi, N.J.; Zhang, J.Z.

1995-08-08

113

The shearing effect of vapor flow on laminar liquid flow in capillaries of heat pipes  

Microsoft Academic Search

For heat pipes having open capillaries in the transport section, vapor flow in the tube influences laminar liquid flow in the capillaries in the opposite direction by the shearing action of the vapor at the liquid's surface. The two-dimensional Navier-Stokes equation for liquid flow in rectangular flow in capillaries was solved by a Fourier transformation. The friction factor for liquid

W. Hufschmidt; E. Burck; G. Dicola; H. Hoffman

1975-01-01

114

MODELLING OF WETTABILITY ALTERATION PROCESSES IN CARBONATE OIL RESERVOIRS  

Microsoft Academic Search

Previous studies have shown that seawater may alter the wettabil- ity in the direction of more water-wet conditions in carbonate reservoirs. The reason for this is that ions from the salt (sulphat, magnesium, calsium, etc) can create a wettability alteration toward more water-wet conditions as salt is absorbed on the rock. In order to initiate a more systematic study of

LIPING YUA; HANS KLEPPEA; SVEIN M. SKJAEVELANDA

115

Modelling of wettability alteration processes in carbonate oil reservoirs  

Microsoft Academic Search

Previous studies have shown that seawater may alter the wettabil- ity in the direction of more water-wet conditions in carbonate reservoirs. The reason for this is that ions from the salt (sulphat, magnesium, calsium, etc) can create a wettability alteration toward more water-wet conditions as salt is absorbed on the rock. In order to initiate a more systematic study of

Liping Yu; Hans Kleppe; Terje Kaarstad; Svein M. Skjaeveland; Steinar Evje; Ingebret Fjelde

2008-01-01

116

Wettability-gradient-driven micropump for transporting discrete liquid drops  

NASA Astrophysics Data System (ADS)

In this paper, we report our efforts toward building a microelectromechanical system-based micropump. The micropump is driven by a wettability gradient and used to transport discrete drops. The gradient in wettability is distributed axisymmetrically, with hydrophobicity of the micropump surface decreasing radially toward the center. Both physical and chemical properties of the surface are altered to obtain the wettability gradient needed for driving the drops. The surface of the micropump is, first, patterned with pre-designed micro-features that define the roughness of the surface and, then, coated with a low-energy interface film. Results show that drops deposited on the surface of the micropump move, in a directional way, along the wettability gradient. The average velocity of the deposited drops is 5 mm s-1. Measured contact angles decrease gradually from 157.0° to 124.2° toward the center of the micropump surface. Maximum driving force exerted by the solid surface on the drops is 12.82 µN. The average size of the drops transported on the surface of the micropump is 2 µL.

Bardaweel, Hamzeh K.; Zamuruyev, Konstantin; Delplanque, Jean-Pierre; Davis, Cristina E.

2013-03-01

117

Wettability of naturally aged silicone and EPDM composite insulators  

Microsoft Academic Search

This paper reports the wettability of aged surfaces and of the bulk of naturally aged silicone and EPDM insulator housings and of silicone elastomer insulator coatings studied. The samples were taken either directly from the insulators or treated by exposing them to corona discharges and\\/or to saline pollution. The results show that the contact angles of the silicone rubber insulator

S. M. Gubanski; A. E. Vlastos

1990-01-01

118

Adjustable wettability of paperboard by liquid flame spray nanoparticle deposition  

Microsoft Academic Search

Liquid flame spray process (LFS) was used for depositing TiOx and SiOx nanoparticles on paperboard to control wetting properties of the surface. By the LFS process it is possible to create either superhydrophobic or superhydrophilic surfaces. Changes in the wettability are related to structural properties of the surface, which were characterized using scanning electron microscope (SEM) and atomic force microscope

Milena Stepien; Jarkko J. Saarinen; Hannu Teisala; Mikko Tuominen; Mikko Aromaa; Jurkka Kuusipalo; Jyrki M. Mäkelä; Martti Toivakka

2011-01-01

119

Directional liquid spreading over chemically defined radial wettability gradients.  

PubMed

We investigate the motion of liquid droplets on chemically defined radial wettability gradients. The patterns consist of hydrophobic fluorinated self-assembled monolayers (SAMs) on oxidized silicon substrates. The design comprises a central hydrophobic circle of unpatterned SAMs surrounded by annular regions of radially oriented stripes of alternating wettability, i.e., hydrophilic and hydrophobic. Variation in the relative width of the stripes allows control over the macroscopic wettability. When a droplet is deposited in the middle, it will start to move over to the radially defined wettability gradient, away from the center because of the increasing relative surface area of hydrophilic matter for larger radii in the pattern. The focus of this article is on a qualitative description of the characteristic motion on such types of anisotropic patterns. The influence of design parameters such as pattern dimensions, steepness of the gradient, and connection between different areas on the behavior of the liquid are analyzed and discussed in terms of advancing and receding contact lines, contact angles, spatial extent, and overall velocity of the motion. PMID:22839421

Bliznyuk, Olesya; Seddon, James R T; Veligura, Vasilisa; Kooij, E Stefan; Zandvliet, Harold J W; Poelsema, Bene

2012-08-09

120

Flow mechanisms, relative permeabilities, and coupling effects in steady-state two-phase flow through porous media. The case of strong wettability  

SciTech Connect

The pore-scale flow mechanisms and the relative permeabilities during steady-state two-phase flow in a glass model pore network were studied experimentally for the case of strong wettability ({theta}{sub e} < 10{degree}). The capillary number, the fluid flow rate ratio, and the viscosity ratio were changed systematically, while all other parameters were kept constant. The flow mechanisms at the microscopic and macroscopic scales were examined visually and videorecorded. As in the case of intermediate wettability, the authors observed that over a broad range of values of the system parameters the pore-scale flow mechanisms include many strongly nonlinear phenomena, specifically, breakup, coalescence, stranding, mobilization, etc. Such microscopically irreversible phenomena cause macroscopic nonlinearity and irreversibility, which make an Onsager-type theory inappropriate for this class of flows. The main effects of strong wettability are that it changes the domains of the system parameter values where the various flow regimes are observed and increases the relative permeability values, whereas the qualitative aspects of the flow remain the same. Currently, a new true-to-mechanism model is being developed for this class of flows.

Avraam, D.G.; Payatakes, A.C. [Univ. of Patras (Greece)

1999-03-01

121

Investigating wettability alteration during MEOR process, a micro/macro scale analysis.  

PubMed

Wettability alteration is considered to be one of the important mechanisms that lead to increased oil recovery during microbial enhanced oil recovery (MEOR) processes. Changes in wettability will greatly influence the petrophysical properties of the reservoir rocks and determine the location, flow and distribution of different fluids inside the porous media. Understanding the active mechanisms of surface wettability changes by the bacteria would help to optimize the condition for more oil recovery. As the mechanisms behind wettability alteration are still poorly understood, the objective of this study is to investigate the wettability alteration at pore scale and find the most effective mechanism of wettability changes in different cases. The experiments were performed on different substrates at fresh condition or aged in crude oil to mimic various wetting conditions. Using an Enterobacter cloacae strain, the influence of bacterial metabolites, bacterial adhesion and bacterial solution with two different carbon sources on wettability were determined for different aging periods. Contact angle measurements were used to quantify the wettability alteration of the solid surfaces. Atomic force microscopy (AFM) experiments were also utilized to combine the macroscopic measurements of wettability with the microscopic study of the surface changes. It was found that the surface wettability could vary from neutral- or oil-wet to water-wet state. Bacterial adhesion and biofilm formation seems to be the dominant mechanism of wettability alteration. The aged glass surfaces regained their initial water wetness where the bacteria could remove the polar and asphaltene compounds from them. PMID:22445747

Karimi, Mahvash; Mahmoodi, Maziyar; Niazi, Ali; Al-Wahaibi, Yahya; Ayatollahi, Shahab

2012-03-07

122

Microbial enhanced oil recovery and wettability research program  

SciTech Connect

This report covers research results for the microbial enhanced oil recovery (MEOR) and wettability research program conducted by EG G Idaho, Inc. at the Idaho National Engineering Laboratory (INEL). The isolation and characterization of microbial species collected from various locations including target oil field environments is underway to develop more effective oil recovery systems for specific applications. The wettability research is a multi-year collaborative effort with the New Mexico Petroleum Recovery Research Center (NMPRRC), to evaluate reservoir wettability and its effects on oil recovery. Results from the wettability research will be applied to determine if alteration of wettability is a significant contributing mechanism for MEOR systems. Eight facultatively anaerobic surfactant producing isolates able to function in the reservoir conditions of the Minnelusa A Sands of the Powder River Basin in Wyoming were isolated from naturally occurring oil-laden environments. Isolates were characterized according to morphology, thermostability, halotolerance, growth substrates, affinity to crude oil/brine interfaces, degradative effects on crude oils, and biochemical profiles. Research at the INEL has focused on the elucidation of microbial mechanisms by which crude oil may be recovered from a reservoir and the chemical and physical properties of the reservoir that may impact the effectiveness of MEOR. Bacillus licheniformis JF-2 (ATCC 39307) has been used as a benchmark organism to quantify MEOR of medium weight crude oils (17.5 to 38.1{degrees}API) the capacity for oil recovery of Bacillus licheniformis JF-2 utilizing a sucrose-based nutrient has been elucidated using Berea sandstone cores. Spacial distribution of cells after microbial flooding has been analyzed with scanning electron microscopy. Also the effect of microbial surfactants on the interfacial tensions (IFT) of aqueous/crude oil systems has been measured. 87 refs., 60 figs., 15 tabs.

Thomas, C.P.; Bala, G.A.; Duvall, M.L.

1991-07-01

123

Capillary-driven self-assembly of microchips on oleophilic\\/oleophobic patterned surface using adhesive droplet in ambient air  

Microsoft Academic Search

This letter describes a capillary-driven self-assembly technique using oleophilic\\/oleophobic patterned surface and adhesive in ambient air environment. We use a topographical microstructure of porous ormocer functionalized with a fluorinated trichlorosilane for the oleophobic area and gold patterns for the oleophilic area. The resulted oleophilic\\/oleophobic patterns show significant wettability contrast for adhesive (Delo 18507), with a contact angle of 119° on

Bo Chang; Veikko Sariola; Susanna Aura; Robin H. A. Ras; Maria Klonner; Harri Lipsanen; Quan Zhou

2011-01-01

124

Wetting Phase Bridges Establish Capillary Continuity Across Open Fractures and Increase Oil Recovery in Mixed-Wet Fractured Chalk  

Microsoft Academic Search

The effect of fractures on oil recovery and in situ saturation development in fractured chalk has been determined at near\\u000a neutral wettability conditions. Fluid saturation development was monitored both in the matrix and in the fractures and the\\u000a mechanisms of fracture crossing were determined using high spatial resolution MRI. Capillary continuity across open oil-filled\\u000a fractures was verified by imaging the water

Eirik Aspenes; Geir Ersland; Arne Graue; Jim Stevens; Bernard A. Baldwin

2008-01-01

125

Capillary separations in metabolomics.  

PubMed

Capillary-based separations offer increased resolution, low mass LOD and, in the case of MS, higher sensitivity. The chemical diversity and wide dynamic range of the metabolome requires systems that offer breadth and depth of analysis. In this review, we will highlight novel chemical innovations, technological advancements and various applications of capillary separations in the field of metabolomics. PMID:21083226

Yuan, Wei; Edwards, James L

2010-05-01

126

Instrumentation for capillary electrochromatography  

Microsoft Academic Search

One of the reasons for the immense interest in capillary electrochromatography (CEC) is its feature to combine chromatographic selectivity with the high efficiency and the miniaturization potential of capillary electrophoresis (CE). The capability of commercial CE instruments to run CEC has enforced the readiness of users and researchers to work on this separation technique. Nevertheless, to fully exploit the potential

Frank Steiner; Bernd Scherer

2000-01-01

127

Nonaqueous capillary electrophoresis  

Microsoft Academic Search

The benefits of non-aqueous capillary electrophoresis have been described in a number of recent publications. The wide selection of organic solvents, with their very different physicochemical properties, broadens our scope to manipulate separation selectivity. The lower currents present in non-aqueous solvents allow the use of high electric field strengths and wide bore capillaries, the latter in turn allowing larger sample

Marja-Liisa Riekkola; Matti Jussila; Simo P Porras; István E Valkó

2000-01-01

128

Influence of wettability conditions on slow evaporation in two-dimensional porous media.  

PubMed

We study numerically the influence of the wettability condition on slow evaporation in two-dimensional pore square networks of aspect ratio 1. We show how evaporation in a hydrophobic network can be simulated numerically by combining imbibition rules and the computation of diffusion transport in the gas phase. Then we conduct a statistical study of drying in hydrophilic or hydrophobic networks based on pore network simulations. We concentrate on the situation where the external transfer resistance and liquid film effect are negligible and the invasion is dominated by capillary effects. It is found that drying in a hydrophilic network is significantly faster than in a hydrophobic one. The dimensionless overall drying time is found to be network size dependent, approaching exponentially a limit for large size hydrophilic networks. The dimensionless average overall drying time is 0.93 and 0.75 in hydrophobic and hydrophilic large networks, respectively. Other properties, such as the overall saturation and the evaporation flux (through the concept of equivalent flat front position) are also studied. In a last part the impact of liquid film flow on the overall drying time fluctuation is briefly investigated for the case of hydrophilic networks. It is found that the films dampen the drying time fluctuations. PMID:17500997

Chapuis, O; Prat, M

2007-04-30

129

Guided corona generates wettability patterns that selectively direct cell attachment inside closed microchannels.  

PubMed

We present a method to create plasma mediated linear protein patterns along the lengths of simple one-inlet-one-outlet straight polydimethylsiloxane microchannels by biasing the delivery of corona discharge at the capillary openings. Pattern widths ranging from 500-1,000 microm were generated in 2 mm wide microchannels with lengths of 0.5, 1.0, or 1.5 cm. Corona-treated surfaces enabled the spatial alignment of C2C12 myoblasts to the adhesive protein-coated regions, facilitating myoblast differentiation into myotubes. Although limited in precision, this protein patterning technique offers the advantages of simplicity and low cost, making it attractive for educational and research environments that lack access to extensive microfabrication facilities. The results also provide a cautionary note to those using corona discharge to increase wettability of microchannels; the surface modification may not be uniform, even within single microchannels being treated depending on settings and positioning of the corona device tips. PMID:20495872

Dixon, Angela; Takayama, Shuichi

2010-10-01

130

Relationship between temperature sensitivity of capillary pressure and soil particle size  

NASA Astrophysics Data System (ADS)

In a review of data in the published literature, we found that the effect of temperature on capillary pressure in natural soils increased with decreasing geometric mean soil particle diameter. This observation had implications both for hydrologic modeling and for elucidating the mechanisms that controlled the temperature sensitivity of capillary pressure. Two mechanisms were suggested to explain this observation. The first mechanism proposed that changes in soil mineral particle size resulted in changes in the proportion of hydrophyllic and hydrophobic surfaces, yielding changes in their wettabilities, and temperature effects on capillary pressure. The second mechanism proposed that the observation was due to the effect of soil particle size on disjoining pressure. A model derived from the second mechanism could be fitted to the available data and yielded parameter estimates consistent with current models of disjoining pressure profiles above surfaces.

Grant, Steven A.; Or, Dani

2004-04-01

131

Capillary micro-switches  

NASA Astrophysics Data System (ADS)

A capillary surface is a liquid/liquid or liquid/gas interface whose shape is determined by surface tension. Capillary surfaces occur when the capillary length is large compared to the container scale, as happens for typical liquids against gas on the sub-millimeter scale on Earth and on the meter scale in the micro-gravity environment of space vehicles. Manipulating capillary surfaces has emerged as a leading strategy for moving liquids on the micro-scale [1]. Practitioners have yet to take advantage of capillary instability in their design of devices, though. We illustrate how the response diagram of a single switch (bi-stable device) can be constructed from that of two capillary elements, how that of a system of switches (a pair) can be built from that of a single switch and finally how understanding the response of the system guides us to observations of new behavior in the laboratory. Experiments on capillary surfaces use either a soap-film analog (10 centimeter scale) or a liquid/gas (millimeter scale) apparatus. Progress is reported on the application of an array of micro-switches to make a controllable adhesion device, with the aim of effecting droplet transport. 1. Cho, Fan, Moon and Kim, "Towards digital microfluidic circuits: creating, transporting, cutting and merging liquid droplets by electrowetting-based actuation." Proc. 15th IEEE Int'l Conf. on MEMS, January 2002.

Steen, Paul; Matalanis, Claude; Hirsa, Amir; Cox, Christhopher

2002-11-01

132

Evaluation of Reservoir Wettability and its Effect on Oil Recovery  

SciTech Connect

This project has three main goals. The first is to achieve improved understanding of the surface and interfacial properties of crude oils and their interactions with mineral surfaces. The second goal is to apply the results of surface studies to improved predictions of oil production in laboratory experiments. Finally, we aim to use the results of this research to recommend ways to improve oil recovery by waterflooding. In order to achieve these goals, the mechanisms of wetting alteration must be explained. We propose a methodology for studying those mechanisms on mineral surfaces, then applying the results to prediction and observation of wetting alteration in porous media. Improved understanding of the underlying mechanisms will show when and how wettability in the reservoir can be altered and under what circumstances that alteration would be beneficial in terms of increased production of oil. In the work reported this quarter, crude oil interactions with Berea sandstone have been used to prepare cores with mixed wettability.

Jill S. Buckley

1998-06-12

133

Wettability of grafted poly(ethylene terephthalate) fibers  

Microsoft Academic Search

Graft copolymerisation of perfluorooctyl-2 ethanol acrylic monomer\\/stearyl methacrylate monomer mixture onto poly(ethylene terephthalate) fibers using benzoyl peroxide as initiator was carried out in order to improve water repellency. By characterising the surface free energy, the degree of water repellency can be evaluated. In this article, the Wilhelmy plate method is used to determinate the surface fiber wettability by probe liquids

Ahmida El-Achari; Abdellah Ghenaim; Claude Cazé

2002-01-01

134

Wettability of nano-epoxies to UHMWPE fibers  

Microsoft Academic Search

Ultra high molecular weight polyethylene (UHMWPE) fibers have a unique combination of outstanding mechanical, physical, and chemical properties. However, as reinforcements for manufacturing high performance composite materials, UHMWPE fibers have poor wettability with most polymers. As a result, the interfacial bonding strength between the fibers and polymer matrices is very low. Recently, developing so-called nano-matrices containing reactive graphitic nanofibers (r-GNFs)

S. Neema; A. Salehi-Khojin; A. Zhamu; W. H. Zhong; S. Jana; Y. X. Gan

2006-01-01

135

Multiplexed capillary electrophoresis system  

DOEpatents

The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

Yeung, Edward S. (Ames, IA); Chang, Huan-Tsang (Silver Spring, MD); Fung, Eliza N. (Ames, IA); Li, Qingbo (Ames, IA); Lu, Xiandan (Ames, IA)

1996-12-10

136

Multiplexed capillary electrophoresis system  

DOEpatents

The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

Yeung, Edward S. (Ames, IA); Li, Qingbo (Ames, IA); Lu, Xiandan (Ames, IA)

1998-04-21

137

Wettability changes of TiO2 nanotube surfaces.  

PubMed

This study examines the effect of environmental and experimental conditions, such as temperature and time, on the wettability properties of titania nanotube (TNT) surfaces fabricated by anodization. The fabricated TNTs are 60-130 nm inner diameter and 7-10 µm height. One-microliter water droplets were used to define the wettability of the TNT surfaces by measuring the contact angles. A digital image analysis algorithm was developed to obtain contact angles, contact radii and center heights of the droplets on the TNT surfaces. Bare titanium foil is inherently less hydrophilic with approximately 60°-80° contact angle. The as-anodized TNT surfaces are more hydrophilic and annealing further increases this hydrophilic property. Furthermore, it was found that the TNT surface became more hydrophobic when aged in air over a period of three months. It is believed that the surface wettability can be changed due to alkane contamination and organic contaminants in an ambient atmosphere. This work can provide guidelines to better specify the environmental conditions that changes surface properties of TNT surfaces and therefore affect their desirable function in specific applications such as orthopedic implants. PMID:21727317

Shin, Dong Hwan; Shokuhfar, Tolou; Choi, Chang Kyoung; Lee, Seong-Hyuk; Friedrich, Craig

2011-07-05

138

Heterogeneous critical nucleation on a completely wettable substrate.  

PubMed

Heterogeneous nucleation of a new bulk phase on a flat substrate can be associated with the surface phase transition called wetting transition. When this bulk heterogeneous nucleation occurs on a completely wettable flat substrate with a zero contact angle, the classical nucleation theory predicts that the free-energy barrier of nucleation vanishes. In fact, there always exists a critical nucleus and a free-energy barrier as the first-order prewetting transition will occur even when the contact angle is zero. Furthermore, the critical nucleus changes its character from the critical nucleus of surface phase transition below bulk coexistence (undersaturation) to the critical nucleus of bulk heterogeneous nucleation above the coexistence (oversaturation) when it crosses the coexistence. Recently, Sear [J. Chem. Phys. 129, 164510 (2008)] has shown, by a direct numerical calculation of nucleation rate, that the nucleus does not notice this change when it crosses the coexistence. In our work, the morphology and the work of formation of critical nucleus on a completely wettable substrate are re-examined across the coexistence using the interface-displacement model. Indeed, the morphology and the work of formation changes continuously at the coexistence. Our results support the prediction of Sear and will rekindle the interest on heterogeneous nucleation on a completely wettable substrate. PMID:21702578

Iwamatsu, Masao

2011-06-21

139

Surface Morphology and Wettability of Sandblasted PEEK and Its Composites.  

PubMed

PolyEtherEtherKetone (PEEK) is an advanced high-performance thermoplastic polymer, and its composites are used extensively in the aeronautical industry. This paper presents an experimental approach to determine the role of sandblasting treatment on surface morphology modifications of PEEK and its composites, with the aim of developing a topographic characterization in order to propose pertinent parameters that correlate with contact angles from wettability measurement. Sandblasting (fine abrasive particle projection) was selected as the surface treatment, in order to obtain various morphologically quasi-isotropic surfaces. Two surface metrological approaches to topographical characterization were used to correlate the wettability behavior with the surface roughness parameters, the first based on 2D profile analysis and the second on 3D topography analysis. Two different unreinforced grades of PEEK and four composites: discontinuous carbon fiber or glass fiber-reinforced, oriented, and unoriented, were studied. The experimental results indicated the sandblasting process duration necessary to reach a morphological steady state. It was stated that one of the pertinent parameters is the mean slope of roughness motif in 2D profile characterization, as confirmed by previous findings for anisotropic morphologies. However, for all cases, a new topographic parameter Sr , combining the surface amplitude and the summit density distribution, is proposed as a factor well-correlated with wettability characteristics. SCANNING 9999:XX-XX, 2013. © 2013 Wiley Periodicals, Inc. PMID:23553954

Ourahmoune, R; Salvia, M; Mathia, T G; Mesrati, N

2013-04-01

140

Wettability influences cell behavior on superhydrophobic surfaces with different topographies.  

PubMed

Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavior on superhydrophobic surfaces is influenced by surface topography and polymer type. Biomimetic superhydrophobic rough surfaces of polystyrene and poly(L-lactic acid) with different micro/nanotopographies were obtained from smooth surfaces using a simple phase-separation based method. Total protein was quantified and showed a less adsorption of bovine serum albumin onto rough surfaces as compared to smooth surfaces of the same material. The mouse osteoblastic MC3T3-E1 cell line and primary bovine articular chondrocytes were used to study cell attachment and proliferation. Cells attached and proliferate better in the smooth surfaces. The superhydrophobic surfaces allowed cells to adhere but inhibited their proliferation. This study indicates that surface wettability, rather than polymer type or the topography of the superhydrophobic surfaces, is a critical factor in determining cell behavior. PMID:22833364

Lourenço, Bianca N; Marchioli, Giulia; Song, Welong; Reis, Rui L; van Blitterswijk, Clemens A; Karperien, Marcel; van Apeldoorn, Aart; Mano, João F

2012-07-26

141

Patterned wettability of oil and water in porous media.  

PubMed

The microscopic wettability state of porous media, based on glass bead packings, after crude oil drainage of brine was investigated using X-ray micro-CT, white-light profilometry, and electron microscopy. Tomography revealed that the bulk residual brine occupied around 10% of void space, located in smaller pores and as pendular rings around bead contacts, in agreement with numerical simulations of drainage. The bead packing contained planar slabs of mica, quartz, and oxidized silicon wafer, which after flushing and disassembly of the pack allowed analysis of their wettability alteration due to deposition of asphaltenes from the crude oil. These substrates exhibited an overall pattern of rings with clean interiors, matching the brine pendular ring size inferred from experimental and simulated drainage, and asphaltene deposition in their exteriors, verifying the mixed wet model of oil reservoir wettability. The extent of asphaltene intrusion into ring interiors and completeness of asphaltene coverage of exteriors both increased with overall deposition tendency for the brine composition. The observed dependence on NaCl concentration and pH was consistent with expectations from DLVO and non-DLVO interactions governing brine thin film rupture and subsequent asphaltene deposition. PMID:19916532

Kumar, Munish; Fogden, Andrew

2010-03-16

142

Layer thickness of hydrophobin films leads to oscillation in wettability.  

PubMed

In nanobiotechnology, the properties of surfaces are often key to sensor applications. If analytes possess a low tolerance or affinity regarding the sensory substrate (surface), then the setup of mediators may be indicated. Hydrophobins enable biocompatible surface functionalization without significant restrictions of the physicochemical substrate properties. Because of the imperfect formation of hydrophobin films, a high variation in surface properties is observed. In this study, we report on the relation between the film thickness of hydrophobin-coated solid surfaces and their wettability. We found that the wettability of protein-coated surfaces strictly depends on the amount of adsorbed protein, as reflected in an oscillation of the contact angles of hydrophobin-coated silicon wafers. Fusion proteins of Ccg2 and HFBI, representatives of class I and II hydrophobins, document the influence of fused peptide tags on the wettability. The orientation of the first crystal nuclei plays a decisive role in the formation of the growing hydrophobin layers. Here, a simple method of deducing the film thickness of hydrophobin assemblies on solid surfaces is presented. The determination of the static contact angle allows the prediction of which part of the protein is exposed to possible analytes. PMID:22458322

Gruner, Leopold J; Ostermann, Kai; Rödel, Gerhard

2012-04-18

143

Wettability changes of TiO2 nanotube surfaces  

NASA Astrophysics Data System (ADS)

This study examines the effect of environmental and experimental conditions, such as temperature and time, on the wettability properties of titania nanotube (TNT) surfaces fabricated by anodization. The fabricated TNTs are 60-130 nm inner diameter and 7-10 µm height. One-microliter water droplets were used to define the wettability of the TNT surfaces by measuring the contact angles. A digital image analysis algorithm was developed to obtain contact angles, contact radii and center heights of the droplets on the TNT surfaces. Bare titanium foil is inherently less hydrophilic with approximately 60°-80° contact angle. The as-anodized TNT surfaces are more hydrophilic and annealing further increases this hydrophilic property. Furthermore, it was found that the TNT surface became more hydrophobic when aged in air over a period of three months. It is believed that the surface wettability can be changed due to alkane contamination and organic contaminants in an ambient atmosphere. This work can provide guidelines to better specify the environmental conditions that changes surface properties of TNT surfaces and therefore affect their desirable function in specific applications such as orthopedic implants.

Shin, Dong Hwan; Shokuhfar, Tolou; Choi, Chang Kyoung; Lee, Seong-Hyuk; Friedrich, Craig

2011-08-01

144

Wettability of Freon hydrates in crude oil/brine emulsions.  

PubMed

The surface energy of petroleum hydrates is believed to be a key parameter with regard to hydrate morphology and plugging tendency in petroleum production. As of today, the surface energy of natural gas hydrates is unknown, but will depend on the fluids in which they grow. In this work, the wettability of Freon hydrates is evaluated from their behavior in crude oil emulsions. For emulsions stabilized by colloidal particles, the particle wettability is a governing parameter for the emulsion behavior. The transition between continuous and dispersed phases as a function of brine volume in crude oil-brine emulsions containing Freon hydrates has been determined for 12 crude oils. Silica particles are used for comparison. The results show that phase inversion is highly dependent on crude oil properties. Based on the measured points of phase inversion, the wettability of the Freon hydrates generated in each system is evaluated as being oil-wet, intermediate-wet, or water-wet. Generation of oil-wet hydrates correlates with low hydrate plugging tendency. The formation of oil-wet hydrates will prevent agglomeration into large hydrate aggregates and plugs. Hence, it is believed that the method is applicable for differentiating oils with regard to hydrate morphology. PMID:15914170

Høiland, S; Askvik, K M; Fotland, P; Alagic, E; Barth, T; Fadnes, F

2005-07-01

145

Displaced capillary dies  

DOEpatents

An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

Kalejs, Juris P. (Wellesley, MA); Chalmers, Bruce (Falmouth, MA); Surek, Thomas (Englewood, CO)

1984-01-01

146

Displaced capillary dies  

DOEpatents

An asymmetrical shaped capillary die made exclusively of graphite is used to grow silicon ribbon which is capable of being made into solar cells that are more efficient than cells produced from ribbon made using a symmetrically shaped die.

Kalejs, Juris P. (Wellesley, MA); Chalmers, Bruce (Falmouth, MA); Surek, Thomas (Englewood, CO)

1982-01-01

147

In situ wettability distribution and wetting stability in outcrop chalk aged in crude oil  

Microsoft Academic Search

This paper reports an investigation of in situ wettability distribution and wetting stability of moderately water-wet and nearly neutral-wet outcrop chalk cores, aged in crude oil at elevated temperature.In this paper, in situ wettability measurements by magnetic resonance imaging (MRI) tomography are shown to give Amott indices that agree well with the standard wettability indices based on average saturations. The

E Aspenes; A Graue; J Ramsdal

2003-01-01

148

CHARACTERIZATION OF MIXED WETTABILITY AT DIFFERENT SCALES AND ITS IMPACT ON OIL RECOVERY EFFICIENCY  

SciTech Connect

The objectives of the this research project were to: (1) Quantify the pore scale mechanisms that determine the wettability state of a reservoir; (2) Study the effect of crude oil, brine and mineral compositions in the establishment of mixed wet states; (3) Clarify the effect of mixed-wettability on oil displacement efficiency in waterfloods; and (4) Develop a new tracer technique to measure wettability, fluid distributions, residual saturations and relative permeabilities.

Mukul M. Sharma; George J. Hirasaki

2003-09-01

149

Capillary Waveguide Biosensor Platform  

Microsoft Academic Search

\\u000a The design and characterization of a fully automated and portable capillary waveguide biosensor are discussed in this chapter.\\u000a Highly specific target recognition is achieved through hybridization of fluid-borne single-stranded DNA sequences extracted\\u000a from natural targets to the complimentary nucleic acid sequence (“capture probe”) bound to the inner surface of a capillary.\\u000a The product of hybridization is enumerated through the use

Harbans S. Dhadwal

150

Clinical applications of capillary electrophoresis  

Microsoft Academic Search

Capillary electrophoresis (CE) is an extremely sensitive technique, which has been used in the clinical laboratory for almost\\u000a 10 yr. The components of CE instrumentation are described, as are injection modes, buffers, and effects of electroosmotic\\u000a flow. The modes of separation used in CE, namely, capillary zone electrophoresis, capillary isoelectric focusing, capillary\\u000a isotachophoresis, and micellar electrokinetic capillary chromatography, are explained.

M. A. Jenkins

2000-01-01

151

Electrically surface-driven switchable wettability of liquid crystal/polymer composite film  

NASA Astrophysics Data System (ADS)

This study demonstrates the electrical control of the surface wettability of liquid crystal and polymer composite film. The application of external voltages significantly affects the surface wettability of the film. This study uses atomic force microscopy to quantitatively characterize the fundamental mechanism responsible for the structurally driven changes in surface properties at various applied voltages. The surface wettability transitions of the film are electrically driven, as shown by reorganized liquid crystal molecules. Measurements of the voltage-dependent surface wettability of the composite film suggest approaches to supporting control applications of future electro-optical nanotechnology devices.

Chiu, Ya-Ping; Shen, Cheng-Yu; Wang, Wen-Ching; Chu, Ting-Yu; Lin, Yi-Hsin

2010-03-01

152

Characterization of Mixed Wettability at Different Scales and its Impact on Oil Recovery Efficiency  

SciTech Connect

The objectives of this project was to: (1) quantify the pore scale mechanisms that determine the wettability state of a reservoir, (2) study the effect of crude oil, brine and mineral compositions in the establishment of mixed wet states, (3) clarify the effect of mixed - wettability on oil displacement efficiency in waterfloods, (4) develop a new tracer technique to measure wettability, fluid distributions, residual saturation's and relative permeabilities, and (5) develop methods for properly incorporating wettability in up-scaling from pore to core to reservoir scales.

Sharma, Mukul M.; Hirasaki, George J.

2002-01-28

153

Wettability studies at the pore level: A new approach by use of Cryo-SEM  

SciTech Connect

Cryo-scanning electron microscopy (Cryo-SEM) is used to study the wettability of reservoir rocks from fluid distribution at irreducible water saturation, S{sub wi}, and residual oil saturation, S{sub or}. Results on mixed-wettability cores point out the importance of composition, distribution, and accessibility of minerals in determining the macroscopic behavior of the rocks. For the studied samples, wettability of sandstones is related to the presence of kaolinite, while wettability of carbonates seems to be related to pore-size distribution.

Robin, M.; Rosenberg, E. [Inst. Francais du Petrole, Rueil-Malmaison (France); Fassi-Fihri, O.

1995-03-01

154

Gas-Filled Capillary Model  

SciTech Connect

We have developed a 1-D, quasi-steady-state numerical model for a gas-filled capillary discharge that is designed to aid in selecting the optimum capillary radius in order to guide a laser beam with the required intensity through the capillary. The model also includes the option for an external solenoid B-field around the capillary, which increases the depth of the parabolic density channel in the capillary, thereby allowing for propagation of smaller laser beam waists. The model has been used to select the parameters for gas-filled capillaries to be utilized during the Staged Electron Laser Acceleration -- Laser Wakefield (STELLA-LW) experiment.

Steinhauer, L. C. [University of Washington, Redmond Plasma Physics Laboratory, Redmond, WA 98052 (United States); Kimura, W. D. [STI Optronics, Inc., Bellevue, WA 98004 (United States)

2006-11-27

155

Surfactant loss: Effects of temperature, salinity, and wettability  

SciTech Connect

Adsorption of sodium dodecylsulfate, Triton X-100, decyltrimethylammonium bromide surfactants onto silica gel and Berea sandstone mineral surfaces has been studied as a function of temperature, solution salt concentration, and mineral surface wettability. Adsorption studies using a flow calorimeter were conducted using pure surfactants and minerals. The studies were then extended to the adsorption of one type of commercial surfactant onto both consolidated and crushed Berea sandstone using column techniques. This has allowed the comparison of different methods to evaluate surfactant losses from flowing rather than static surfactant solutions. 20 refs., 15 figs., 37 tabs.

Noll, L.A.; Gall, B.L.; Crocker, M.E.; Olsen, D.K.

1989-05-01

156

Adsorption of surfactants on minerals for wettability control in improved oil recovery processes  

Microsoft Academic Search

Chemical-flooding schemes for recovering residual oil have been in general less than satisfactory due to loss of chemicals by adsorption on reservoir rocks, precipitation, and resultant changes in rock wettability. Adsorption and wettability changes are determined mainly by the chemical structure and mix of the surfactants, surface properties of the rock, composition of the oil and reservoir fluids, nature of

P. Somasundaran; L. Zhang

2006-01-01

157

Infiltration and redistribution of PCE in a system containing spatial wettability variations  

Microsoft Academic Search

Wettability variations can exist in many subsurface environments as a consequence of spatial and temporal variability in aqueous phase chemistry, variations in grain mineralogy, the presence of organic matter, and\\/or interactions of the formation solids and surface active organic contaminants. This presentation describes results of a laboratory and modeling investigation designed to explore and quantify the effect of spatial wettability

D. M. O'Carroll; S. A. Bradford; L. M. Abriola

2001-01-01

158

Interaction of cultured human endothelial cells with polymeric surfaces of different wettabilities  

Microsoft Academic Search

The in vitro interaction of human endothelial cells (HEC) and polymers with different wettabilities in culture medium containing serum was investigated. Optimal adhesion of HEC generally occurred onto moderately wettable polymers. Within a series of cellulose type of polymers the cell adhesion increased with increasing contact angle of the polymer surfaces. Proliferation of HEC occurred when adhesion was followed by

Wachem van P. B; T. Beugeling; J. Feijen; A. Bantjes; J. P. Detmers; Aken van W. G

1985-01-01

159

Effects of surface wettability and contact time on protein adhesion to biomaterial surfaces  

Microsoft Academic Search

Atomic force microscopy (AFM) was used to directly measure the adhesion forces between three test proteins and low density polyethylene (LDPE) surfaces treated by glow discharge plasma to yield various levels of water wettability. The adhesion of proteins to the LDPE substrates showed a step dependence on the wettability of surfaces as measured by the water contact angle (?). For

Li-Chong Xu; Christopher A. Siedlecki

2007-01-01

160

Role of wettability and nanoroughness on interactions between osteoblast and modified silicon surfaces  

Microsoft Academic Search

Development of new biomaterials is a constant in regenerative medicine. A biomaterial’s surface properties, such as wettability, roughness, surface energy, surface charge, chemical functionalities and composition, are determinants of cell adhesion and subsequent tissue behavior. Thus, the main aim of this study was to analyze the correlation between changes in wettability without topographical variation and the response of osteoblast-like cells.

Miguel Padial-Molina; Pablo Galindo-Moreno; Juan Emilio Fernández-Barbero; Francisco O’Valle; Ana Belén Jódar-Reyes; Juan Luis Ortega-Vinuesa; Pedro J. Ramón-Torregrosa

2011-01-01

161

On the influence of flow conditions and wettability on blood material interactions  

Microsoft Academic Search

In this review, we hypothesise that, next to biocompatibility, optimal blood compatibility depends on a combination of biomaterials wettability and the shear stress prevailing in the device. The wettability is discussed in seven different categories of devices, that differ substantially from each other with regard to shear stress and exposure time. These seven categories are stents, prosthetic heart valves, vascular

H. T. Spijker; R. Graaff; P. W. Boonstra; H. J. Busscher; W. van Oeveren

2003-01-01

162

Pore-level scenario for the development of mixed-wettability in oil reservoirs.  

National Technical Information Service (NTIS)

Understanding the role of thin films in porous media is vital if wettability is to be elucidated at the pore level. The type and thickness of films coating pore walls determines reservoir wettability and whether or not reservoir rock can be altered from i...

A. R. Kovscek H. Wong C. J. Radke

1992-01-01

163

Surface modification of silicon and PTFE by laser surface treatment: improvement of wettability  

Microsoft Academic Search

Laser surface treatment was used to modify the surface of silicon and PTFE (polytetrafluoroethylene). This method is in order to improve its wettability and adhesion characteristics. Using a 4th harmonic Nd:YAG pulse laser (lambda = 266 nm, pulse), we determined the wettability and the adhesion characteristics of silicon and PTFE surfaces developed by the laser irradiation. Particularly, surface treatment of

Dong-Yong Kim; Kyoung-cheol Lee; Cheon Lee

2003-01-01

164

A wettability gradient as a tool to study protein adsorption and cell adhesion on polymer surfaces  

Microsoft Academic Search

A new method for preparing a wettability gradient on polymer surfaces was developed. Low density polyethylene sheets were treated in air with corona from a knife-type electrode whose power gradually increases along the sample length. The polymer surfaces oxidized gradually with the increasing power and the wettability gradient was created on the surfaces as evidenced by the measurement of water

Jin Ho Lee; Hai Bang Lee

1993-01-01

165

Enhancing the settlement and attachment strength of pediveligers of Mytilus galloprovincialis bychanging surface wettability and microtopography  

Microsoft Academic Search

Surface wettability and microtopography can either enhance or deter larval settlement of many sessile marine organisms. This study quantifies the effect of these surface properties on the settlement of pediveligers of Mytilus galloprovincialis, using polymers spanning a range of wettability and microtextured polydimethylsiloxane (PDMS). Furthermore, the adhesion strength of settled pediveligers on microtextured PDMS surfaces was quantified using a flow

C. Carl; A. J. Poole; B. A. Sexton; F. L. Glenn; M. J. Vucko; M. R. Williams; S. Whalan; R. de Nys

2012-01-01

166

Wettability of pristine and alkyl-functionalized graphane  

NASA Astrophysics Data System (ADS)

Graphane is a hydrogenated form of graphene with high bandgap and planar structure insensitive to a broad range of chemical substitutions. We describe an atomistic simulation approach to predict wetting properties of this new material. We determine the contact angle to be 73°. The lower hydrophobicity compared to graphene is explained by the increased planar density of carbon atoms while we demonstrate that the presence of partial charges on carbon and hydrogen atoms plays only a minor role. We further examine the effects of graphane functionalization by alkyl groups of increasing chain lengths. The gradual increase in contact angle with chain length offers a precise control of surface wettability. A saturated contact angle of 114° is reached in butylated form. We find the saturation of contact angle with respect to the length of the functional groups to coincide with the loss of water's ability to penetrate the n-alkyl molecular brush and interact with carbon atoms of the underlying lattice. Since no experimental data have yet become available, our modeling results provide the first estimate of the wettability of graphane. The results also show how its alkyl functionalization provides the basis for a variety of chemical modifications to tune hydrophilicity while preserving the planar geometry of the substrate.

Vanzo, Davide; Bratko, Dusan; Luzar, Alenka

2012-07-01

167

Salinity Influence on Interfacial Area, Wettability, and NAPL Recovery  

NASA Astrophysics Data System (ADS)

Wettability, the tendency of rock or sediment particle surfaces to be preferentially wet by one fluid phase, has a strong influence on the distribution and flow of immiscible fluids in oil reservoirs or aquifers. The efficiency of oil and non-aqueous phase liquid (NAPL) recovery processes and the displacement and production of oil/NAPL by fluids injected into the reservoir or aquifer depend on the wetting properties of the rock/sediment particle surfaces. Effects of salinity on wettability and residual oil saturation during water flooding are of particular interest in the petroleum industry with some reservoirs. It was indicated that the residual oil saturation may be reduced significantly by flooding with low salinity water instead of seawater or brine. This observation may be also true in NAPL recovery from contaminated aquifers. NAPL recovery enhancement may be achieved by manipulating the salinity of the remedial fluid. Two sets of 8 core-flooding column experiments have been completed, using decane and Alaska North Slope (ANS) crude oil as surrogate NAPLs. Unconsolidated sand packs were used as representative porous media. NAPL removal was conducted by flushing column at residual NAPL saturation using water with salinity ranging from 0% to 8% wt of NaCl. The NAPL-water interfacial area (anw, cm-1) was measured and used as an indicator for the wettability characteristics of the packed sand. Sodium Dodecyl Benzene Sulfonate (SDBS) was used as an interfacial partitioning tracer and Pentafluoro Benzoic acid (PFBA) was used as a non-reactive and non-partitioning tracer. NAPL was imbibed into an initially water saturated column, using positive displacement methods. NAPL was then flushed out using water at certain salinity. When the column attained a residual NAPL saturation after each water flushing displacement, the partitioning and conservative tracer experiments were conducted separately, to characterize the specific NAPL-water interfacial areas, and the wettability status. Water with 8%, 4%, 2%, 0% wt NaCl salinity was used to displace NAPL from the sand column sequentially. The interfacial tension (IFT) between the salinity water and the ANS oil was monitored. The residual oil saturations indicated that the fraction of NAPL retained in the column increased after water flushing as the salinity in the displacing water increased from 0 to 8%, clearly confirming the earlier findings that lower salinity may cause additional oil to be released. The NAPL-water interfacial area, anw, does not show a monotonic dependence on salinity; instead, anw shows an increasing trend with increasing salinity in the lower salinity range, and the opposite trend at high salinity values. The maximum anw was obtained in systems flushed with 2% salinity water. This trend appears to be consistent with a similar nonlinear dependence of interfacial tension on salinity, and might be an indication of wettability alternation. The observation of this research shread lights on the optimum operation in NAPL removal. The IFT change between NAPL and the salinity water might be attributed to the enhanced NAPL recovery.

Zhong, L.; Valenta, M. M.

2007-12-01

168

Capillary Waveguide Biosensor Platform  

Microsoft Academic Search

The design and characterization of a fully automated and portable capillary waveguide biosensor are discussed in this chapter. Highly specific target recognition is achieved through hybridization of fluid-borne single-stranded DNA sequences extracted from natural targets to the complimentary nucleic acid sequence (\\

Harbans S. Dhadwal

2010-01-01

169

Capillary rise of superspreaders  

Microsoft Academic Search

Trisiloxane surfactants, known as ‘superspreaders’, are commonly employed in numerous applications where enhanced wetting is of the utmost importance. The underlying mechanisms of superspreader wetting have been a focus of scientific interest for ca. 2 decades, and a number of mechanisms have been proposed to explain the unique trisiloxane dynamics. We have studied trisiloxane behaviour in thin capillaries to get

Jovana Radulovic; Khellil Sefiane; Martin E. R. Shanahan

2011-01-01

170

Capillary fiber microvertex detectors  

NASA Astrophysics Data System (ADS)

The possibility of using high resolution tracking devices based on thin glass capillary arrays filled with liquid scintillator is presented. This technique provides high hit densities, good position resolution and radiation hardness, better than any other type of tracking devices with comparable performances.

Ferroni, Fernando; Martellotti, Giuseppe

1995-02-01

171

Capillary Force on a Nanoscale Tip in Dip-Pen Nanolithography  

NASA Astrophysics Data System (ADS)

Monte Carlo simulation has been used to characterize the capillary force due to the condensation of a liquid meniscus between a tip with a nanoscale asperity and a flat surface. To consider both hydrophobic and hydrophilic molecules coating the tip as a model of dip-pen nanolithography, tips with various wettabilities are studied. The capillary force due to the meniscus is calculated for various saturations (humidities). We have implemented a thermodynamic integration technique that can project the force into energetic and entropic contributions. In most cases, the force is mainly energetic in origin. At the snap-off separation where the meniscus disappears, the tip feels a significant entropic force at high saturation. Our calculation shows nonmonotonic behavior of the pull-off force as a function of saturation, which is in qualitative accord with experiments.

Jang, Joonkyung; Schatz, George C.; Ratner, Mark A.

2003-04-01

172

Carbon nanotube patterning with capillary micromolding of catalyst.  

PubMed

Patterning of multi-walled carbon nanotube (MWNT) in a plasma enhanced chemical vapor deposition (PECVD) chamber has been achieved by catalyst patterning using capillary micromolding process. Iron acetate catalyst nanoparticles were dissolved in ethanol and mold was fabricated with polydimethylsiloxane (PDMS). The ethanol solution containing catalyst nanoparticles was filled into the microchannel formed between PDMS mold and Si-wafer by capillary force. The capillary action of different solvents was simulated by commercial CFD-ACE+ simulation code to determine optimal solvents. Simulated result shows that the choice of solvent was critical in this capillary filling process. After the catalyst patterning, MWNT was grown at 700 approximately 800 degrees C by PECVD process using CH4 and Ar gas in a scale of approximately 10 micro-meters in a tubular inductively coupled plasma reactor. Grown CNTs were analyzed by FE-SEM and Raman Spectroscopy. PMID:18047145

Lee, Jaewon; Ryu, Choonghan; Lee, Sungwoo; Jung, Donggeun; Kim, Hyoungsub; Chae, Heeyeop

2007-11-01

173

Evaluation of Reservoir Wettability and its Effect on Oil Recovery.  

SciTech Connect

We report on the first year of the project, `Evaluation of Reservoir Wettability and its Effect on Oil Recovery.` The objectives of this five-year project are (1) to achieve improved understanding of the surface and interfacial properties of crude oils and their interactions with mineral surfaces, (2) to apply the results of surface studies to improve predictions of oil production from laboratory measurements, and (3) to use the results of this research to recommend ways to improve oil recovery by waterflooding. During the first year of this project we have focused on understanding the interactions between crude oils and mineral surfaces that establish wetting in porous media. As background, mixed-wetting and our current understanding of the influence of stable and unstable brine films are reviewed. The components that are likely to adsorb and alter wetting are divided into two groups: those containing polar heteroatoms, especially organic acids and bases; and the asphaltenes, large molecules that aggregate in solution and precipitate upon addition of n-pentane and similar agents. Finally, the test procedures used to assess the extent of wetting alteration-tests of adhesion and adsorption on smooth surfaces and spontaneous imbibition into porous media are introduced. In Part 1, we report on studies aimed at characterizing both the acid/base and asphaltene components. Standard acid and base number procedures were modified and 22 crude oil samples were tested. Our approach to characterizing the asphaltenes is to focus on their solvent environment. We quantify solvent properties by refractive index measurements and report the onset of asphaltene precipitation at ambient conditions for nine oil samples. Four distinct categories of interaction mechanisms have been identified that can be demonstrated to occur when crude oils contact solid surfaces: polar interactions can occur on dry surfaces, surface precipitation is important if the oil is a poor solvent for its asphaltenes, and acid/base and ion-binding interactions occur in the presence of water. Specific instances when each of these mechanisms is dominant can be identified using crude oils of different acid number, base number, and solvent quality. Part 2 of this project is devoted to improved assessment of wetting. We report on a baseline study of crude oil interactions with mica surfaces that shows wettability alteration characteristics that are comparable to those reported previously for glass surfaces. Mica has advantages over amorphous glass that make it a better choice as a standard surface for wettability testing, especially for tests at high temperatures.

Buckley, J.S.

1998-01-15

174

Wettability of oil-producing reservoir rocks as determined from X-ray photoelectron spectroscopy  

SciTech Connect

Wettability has a dominant effect in oil recovery by water-flooding and in many other processes of industrial and environmental interest. Recently, the suggestion has been made the surface science analytical techniques (SSAT) could be used to rapidly determine the wettability of reservoir materials. Here, the authors bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of producing reservoir rocks. For a suite of freshly exposed fracture surfaces of rocks they investigate the relationship between wettability and surface composition as determined from XPS. The classical wettability index as measured with the Amott-Harvey tests is used here as an indicator of the wettability of natural sandstones. The XPS spectra of oil-wet surfaces of rocks reveal the existence of organic carbon and also of an organic silicon species, of the kind Si-CH relevant to silanes, having a well-defined binding energy which differs from that of the Si-O species of mineral grains. The authors provide quantifiable evidence that chemisorbed organic material on the pore surfaces defines the oil-wetting character of various reservoir sandstones studied here which on a mineralogic basis are expected to be water-wet. This view is supported by a strong correlation between C content of pore surfaces and rock wettability. The results also suggest a correlation between organic silicon content on the pore surfaces and rock hydrophobicity.

Toledo, P.G. [Univ. of Concepcion (Chile); Araujo, Y.C.; Leon, V. [Intevep, S.A., Caracas (Venezuela)

1996-11-10

175

Wettability of Oil-Producing Reservoir Rocks as Determined from X-ray Photoelectron Spectroscopy  

PubMed

Wettability has a dominant effect in oil recovery by waterflooding and in many other processes of industrial and environmental interest. Recently, the suggestion has been made that surface science analytical techniques (SSAT) could be used to rapidly determine the wettability of reservoir materials. Here, we bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of producing reservoir rocks. For a suite of freshly exposed fracture surfaces of rocks we investigate the relationship between wettability and surface composition as determined from XPS. The classical wettability index as measured with the Amott-Harvey test is used here as an indicator of the wettability of natural sandstones. The XPS spectra of oil-wet surfaces of rocks reveal the existence of organic carbon and also of an "organic" silicon species, of the kind Si-CH relevant to silanes, having a well-defined binding energy which differs from that of the Si-O species of mineral grains. We provide quantifiable evidence that chemisorbed organic material on the pore surfaces defines the oil-wetting character of various reservoir sandstones studied here which on a mineralogic basis are expected to be water-wet. This view is supported by a strong correlation between C content of pore surfaces and rock wettability. The results also suggest a correlation between organic silicon content on the pore surfaces and rock hydrophobicity. PMID:8954667

Toledo; Araujo; Leon

1996-11-10

176

The responses to surface wettability gradients induced by chitosan nanofilms on microtextured titanium mediated by specific integrin receptors.  

PubMed

Microtexture and chemistry of implant surfaces are important variables for modulating cellular responses. Surface chemistry and wettability are connected directly. While each of these surface properties can influence cell response, it is difficult to decouple their specific contributions. To address this problem, the aims of this study were to develop a surface wettability gradient with a specific chemistry without altering micron scale roughness and to investigate the role of surface wettability on osteoblast response. Microtextured sandblasted/acid-etched (SLA, Sa = 3.1 ?m) titanium disks were treated with oxygen plasma to increase reactive oxygen density on the surface. At 0, 2, 6, 10, and 24 h after removing them from the plasma, the surfaces were coated with chitosan for 30 min, rinsed and dried. Modified SLA surfaces are denoted as SLA/h in air prior to coating. Surface characterization demonstrated that this process yielded differing wettability (SLA0 < SLA2 < SLA10 < SLA24) without modifying the micron scale features of the surface. Cell number was reduced in a wettability-dependent manner, except for the most water-wettable surface, SLA24. There was no difference in alkaline phosphatase activity with differing wettability. Increased wettability yielded increased osteocalcin and osteoprotegerin production, except on the SLA24 surfaces. mRNA for integrins ?1, ?2, ?5, ?1, and ?3 was sensitive to surface wettability. However, surface wettability did not affect mRNA levels for integrin ?3. Silencing ?1 increased cell number with reduced osteocalcin and osteoprotegerin in a wettability-dependent manner. Surface wettability as a primary regulator enhanced osteoblast differentiation, but integrin expression and silencing ?1 results indicate that surface wettability regulates osteoblast through differential integrin expression profiles than microtexture does. The results may indicate that both microtexture and wettability with a specific chemistry have important regulatory effects on osseointegration. Each property had different effects, which were mediated by different integrin receptors. PMID:22835642

Park, Jung Hwa; Wasilewski, Christine E; Almodovar, Noelia; Olivares-Navarrete, Rene; Boyan, Barbara D; Tannenbaum, Rina; Schwartz, Zvi

2012-07-24

177

The responses to surface wettability gradients induced by chitosan nanofilms on microtextured titanium mediated by specific integrin receptors  

PubMed Central

Microtexture and chemistry of implant surfaces are important variables for modulating cellular responses. Surface chemistry and wettability are connected directly. While each of these surface properties can influence cell response, it is difficult to decouple their specific contributions. To address this problem, the aims of this study were to develop a surface wettability gradient with a specific chemistry without altering micron scale roughness and to investigate the role of surface wettability on osteoblast response. Microtextured sandblasted/acid-etched (SLA, Sa = 3.1 ?m) titanium disks were treated with oxygen plasma to increase reactive oxygen density on the surface. At 0, 2, 6, 10, and 24 h after removing them from the plasma, the surfaces were coated with chitosan for 30 min, rinsed and dried. Modified SLA surfaces are denoted as SLA/h in air prior to coating. Surface characterization demonstrated that this process yielded differing wettability (SLA0 < SLA2 < SLA10 < SLA24) without modifying the micron scale features of the surface. Cell number was reduced in a wettability-dependent manner, except for the most water-wettable surface, SLA24. There was no difference in alkaline phosphatase activity with differing wettability. Increased wettability yielded increased osteocalcin and osteoprotegerin production, except on the SLA24 surfaces. mRNA for integrins ?1, ?2, ?5, ?1, and ?3 was sensitive to surface wettability. However, surface wettability did not affect mRNA levels for integrin ?3. Silencing ?1 increased cell number with reduced osteocalcin and osteoprotegerin in a wettability-dependent manner. Surface wettability as a primary regulator enhanced osteoblast differentiation, but integrin expression and silencing ?1 results indicate that surface wettability regulates osteoblast through differential integrin expression profiles than microtexture does. The results may indicate that both microtexture and wettability with a specific chemistry have important regulatory effects on osseointegration. Each property had different effects, which were mediated by different integrin receptors.

Park, Jung Hwa; Wasilewski, Christine E.; Almodovar, Noelia; Olivares-Navarrete, Rene; Boyan, Barbara D.; Tannenbaum, Rina; Schwartz, Zvi

2013-01-01

178

Effects of simulated storage on the solder wettability of inhibited substrates  

SciTech Connect

Solder wettability of Class II environmentally exposed Cu substrates coated with an organic solderability preservative (OSP) is being investigated. The OSP coatings slightly retarded the wetting behavior of 60Sn-40Pb solder during baseline testing of unaged coupons. A nominal increase in wetting angle, or decrease in wettability, was observed on the inhibited surfaces, particularly when less active fluxes were used. Small increases in the wetting time and decreases in the wetting rate were also measured. Simulated accelerated aging tests are underway to determine the effects of aging in a typical indoor industrial environment on the solder wettability of OSP coated Cu.

Hosking, F.M.; Sorensen, N.R.

1992-12-01

179

Effects of simulated storage on the solder wettability of inhibited substrates  

SciTech Connect

Solder wettability of Class II environmentally exposed Cu substrates coated with an organic solderability preservative (OSP) is being investigated. The OSP coatings slightly retarded the wetting behavior of 60Sn-40Pb solder during baseline testing of unaged coupons. A nominal increase in wetting angle, or decrease in wettability, was observed on the inhibited surfaces, particularly when less active fluxes were used. Small increases in the wetting time and decreases in the wetting rate were also measured. Simulated accelerated aging tests are underway to determine the effects of aging in a typical indoor industrial environment on the solder wettability of OSP coated Cu.

Hosking, F.M.; Sorensen, N.R.

1992-01-01

180

Rapid control of switchable oil wettability and adhesion on the copper substrate.  

PubMed

We described a facile approach to rapidly achieve the reversible oil wettability and adhesion transition on the copper substrate. Plasma treatment and surface fluorination were used to tune the surface composition, and this tunability of the surface composition, along with the stable surface roughness, gave rise to the switchable wettability varying from superoleophobicity to superoleophilicity and reversible oil adhesion between sliding superoleophobicity and sticky superoleophobicity. It took only 1.25 min to realize the whole wettability transition and 5 min for the whole adhesion transition. Additionally, the application of a sticky superoleophobic surface was demonstrated. This study represents an important addition to the field of functional superoleophobic materials. PMID:22032612

Zhu, Xiaotao; Zhang, Zhaozhu; Xu, Xianghui; Men, Xuehu; Yang, Jin; Zhou, Xiaoyan; Xue, Qunji

2011-11-09

181

Separate effects of surface roughness, wettability, and porosity on the boiling critical heat flux  

NASA Astrophysics Data System (ADS)

The separate effects of surface wettability, porosity, and roughness on the critical heat flux (CHF) of water were examined using engineered surfaces. Values explored were 0, 5, 10, and 15 ?m for Rz (roughness), <5°, ~75°, and >110° for static contact angle (wettability), and 0 and 50% for pore volume fraction. The porous hydrophilic surface enhanced CHF by 50%-60%, while the porous hydrophobic surface resulted in a reduction of CHF by 97%. Wettability had little effect on the smooth non-porous surface CHF. Surface roughness (Ra, Rq, Rz) had no effect on CHF within the limit of this database.

O'Hanley, Harry; Coyle, Carolyn; Buongiorno, Jacopo; McKrell, Tom; Hu, Lin-Wen; Rubner, Michael; Cohen, Robert

2013-07-01

182

Protein patterning utilizing region-specific control of wettability by surface modification under atmospheric pressure  

NASA Astrophysics Data System (ADS)

Wettability control can be crucial in improving the uniformity of selective protein immobilization in high-density microarrays. In this study, we propose an atmospheric-pressure plasma-enhanced chemical vapor deposition (AP-PECVD)-based method in conjunction with photolithography to implement region-specific control of wettability on Si substrate. The proposed PECVD method under atmospheric pressure condition would be a useful alternative of conventional reactive plasma-based treatments methods requiring vacuum condition for uniform protein patterning. Layers with dissimilar wettability and roughness prepared by AP-PECVD process using tetraethoxysilane (TEOS) or TEOS-O2 as precursors could realize uniform protein patterning in a micrometer-scale.

Lee, Donghee; Kwon, Min-Sung; Hyun, Ji-Chul; Jun, Chang-Duk; Chung, Euiheon; Yang, Sung

2013-09-01

183

Evaluation of Reservoir Wettability and its Effect on Oil Recovery  

SciTech Connect

This project has three main goals. The first is to achieve improved understanding of the surface and interfacial properties of crude oils and their interactions with mineral surfaces. The second goal is to apply the results of surface studies to improved predictions of oil production in laboratory experiments. Finally, we aim to use the results of this research to recommend ways to improve oil recovery by waterflooding. In order to achieve these goals, the mechanisms of wetting alteration must be explained. We propose a methodology for studying those mechanisms on mineral surfaces, then applying the results to prediction and observation of wetting alteration in porous media. Improved understanding of the underlying mechanisms will show when and how wettability in the reservoir can be altered and under what circumstances that alteration would be beneficial in terms of increased production of oil.

Buckley, Jill S.

1999-11-09

184

Evaluation of Reservoir Wettability and its Effect on Oil Recovery  

SciTech Connect

This project has three main goals. The first is to achieve improved understanding of the surface and interfacial properties of crude oils and their interactions with mineral surfaces. The second goal is to apply the results of surface studies to improved predictions of oil production in laboratory experiments. Finally, we aim to use the results of this research to recommend ways to improve oil recovery by waterflooding. In order to achieve these goals, the mechanisms of wetting alteration must be explained. We propose a methodology for studying those mechanisms on mineral surfaces, then applying the results to prediction and observation of wetting alteration in porous media. Improved understanding of the underlying mechanisms will show when and how wettability in the reservoir can be altered and under what circumstances that alteration would be beneficial in terms of increased production of oil.

Jill S. Buckley

1998-04-13

185

Semipreparative capillary electrochromatography.  

PubMed

Capillaries with inner diameters of 550 microm have successfully been packed with 1.5-microm octadecyl silica particles using frits made of macroporous polymers by the UV photopolymerization of a solution of glycidyl methacrylate and trimethylolpropane trimethacrylate. This type of frit is found superior to one made of low-melting point poly(styrene-co-divinylbenzene) beads. Bubble formation is not observed to occur within these capillary columns under our experimental conditions. Separations can be achieved with sample injection volumes as high as 1 microL. To demonstrate its semipreparative use, a mixture of 500 nL of taxol (20 mM) and its precursor, baccatin III (30 mM), is separated using such a column with a Tris buffer. PMID:11354480

Chen, J R; Zare, R N; Peters, E C; Svec, F; Frechét, J J

2001-05-01

186

[Venoruton and capillary permeability].  

PubMed

A new system to evaluate capillary permeability, the vacuum suction chamber (VSC) device, was used to assess the effects of Venoruton in patients with venous hypertension. A temporary, superficial skin lesion (wheal) was produced with the VSC device by negative pressure (30 mmHg) applied for 10 minutes on the internal, perimalleolar region. Wheals disappear in less than 60 minutes in normals while in patients with venous hypertension the wheal is more persistent, requiring a significantly longer time to disappear. This new technique was used in association with laser-Doppler flowmetry to evaluate the efficacy of Venoruton (1000 mgs t.i.d.) administered for 2 weeks on venous hypertension. Results indicate a positive effect of Venoruton in reducing the abnormally increased capillary permeability in venous hypertension and are proportional to the changes observed in signs and symptoms after treatment. PMID:2779806

Cesarone, M R; Laurora, G; Gabini, M; Errichi, B M; Candiani, C; Belcaro, G

1989-05-01

187

Pore-lining composition and capillary breakthrough pressure of mudstone caprocks : sealing efficiency of geologic CO2 storage sites.  

SciTech Connect

Subsurface containment of CO2 is predicated on effective caprock sealing. Many previous studies have relied on macroscopic measurements of capillary breakthrough pressure and other petrophysical properties without direct examination of solid phases that line pore networks and directly contact fluids. However, pore-lining phases strongly contribute to sealing behavior through interfacial interactions among CO2, brine, and the mineral or non-mineral phases. Our high resolution (i.e., sub-micron) examination of the composition of pore-lining phases of several continental and marine mudstones indicates that sealing efficiency (i.e., breakthrough pressure) is governed by pore shapes and pore-lining phases that are not identifiable except through direct characterization of pores. Bulk X-ray diffraction data does not indicate which phases line the pores and may be especially lacking for mudstones with organic material. Organics can line pores and may represent once-mobile phases that modify the wettability of an originally clay-lined pore network. For shallow formations (i.e., < {approx}800 m depth), interfacial tension and contact angles result in breakthrough pressures that may be as high as those needed to fracture the rock - thus, in the absence of fractures, capillary sealing efficiency is indicated. Deeper seals have poorer capillary sealing if mica-like wetting dominates the wettability.

Petrusak, Robin (Advanced Resources International, Inc., Arlington, VA); Heath, Jason E.; McPherson, Brian J. O. L. (University of Utah, Salt Lake City, UT); Dewers, Thomas A.; Kotula, Paul Gabriel

2010-08-01

188

Pore-lining composition and capillary breakthrough pressure of mudstone caprocks : sealing efficiency at geologic CO2 storage sites.  

SciTech Connect

Subsurface containment of CO2 is predicated on effective caprock sealing. Many previous studies have relied on macroscopic measurements of capillary breakthrough pressure and other petrophysical properties without direct examination of solid phases that line pore networks and directly contact fluids. However, pore-lining phases strongly contribute to sealing behavior through interfacial interactions among CO2, brine, and the mineral or non-mineral phases. Our high resolution (i.e., sub-micron) examination of the composition of pore-lining phases of several continental and marine mudstones indicates that sealing efficiency (i.e., breakthrough pressure) is governed by pore shapes and pore-lining phases that are not identifiable except through direct characterization of pores. Bulk X-ray diffraction data does not indicate which phases line the pores and may be especially lacking for mudstones with organic material. Organics can line pores and may represent once-mobile phases that modify the wettability of an originally clay-lined pore network. For shallow formations (i.e., < {approx}800 m depth), interfacial tension and contact angles result in breakthrough pressures that may be as high as those needed to fracture the rock - thus, in the absence of fractures, capillary sealing efficiency is indicated. Deeper seals have poorer capillary sealing if mica-like wetting dominates the wettability. We thank the U.S. Department of Energy's National Energy Technology Laboratory and the Office of Basic Energy Sciences, and the Southeast and Southwest Carbon Sequestration Partnerships for supporting this work.

Heath, Jason E.; Nemer, Martin B.; McPherson, Brian J. O. L. (University of Utah, Salt Lake City, UT); Dewers, Thomas A.; Kotula, Paul Gabriel

2010-12-01

189

Pinchoff Structures resulting from Capillary-driven Breakup  

Microsoft Academic Search

Understanding the way in which a connected volume of fluid becomes disconnected under the action of surface tension is of practical and scientific value. By its very nature, many decades of length scales are probed when a fluid body splits into two or more pieces. The relevance or not of these scales to observed structures depends on the active capillary

P. H. Steen; Y.-J. Chen

1997-01-01

190

Wettability conundrum: Discrepancies of soft contact lens performance in vitro and in vivo  

NASA Astrophysics Data System (ADS)

The recognition and appreciation of soft contact lenses as simple, efficient and aesthetically gratifying vision-correction devices is ever growing, especially among younger population. Stable thin tear film uniformly spread over corrective lens surface is essential for acute vision, and also for comfortable and safe contact lens wear. The significant efforts have been invested by the contact lens industry to develop soft lens surface that is completely wet by tear aqueous in the ocular environment. Number of the publications dedicated to the wettability properties of the soft hydrogel lenses is on the steady rise. However, the clinical results show that no unambiguous correlation emerges when lens surface wettability in vitro is judged against tear film stability evaluated in vivo. This paper assesses and compares the modern techniques used for evaluation of soft contact lens surface wettability and reports some findings regarding relations between lens surface wettability in vitro and in vivo.

Svitova, T. F.; Lin, M. C.

2011-08-01

191

Thermally controlled wettability of a nanoporous membrane grafted with catechol-tethered poly(N-isopropylacrylamide).  

PubMed

A nanoporous membrane is coated with catechol-tethered poly(N-isopropylacrylamide). The thermosensitive variation of surface wettability determines the hindered diffusivity of dextran (40 kDa) through the nanopores. PMID:22783550

Kim, Jee Seon; Kim, Taek Gyung; Kong, Won Ho; Park, Tae Gwan; Nam, Yoon Sung

2012-07-11

192

Modeling Wettability Alteration using Chemical EOR Processes in Naturally Fractured Reservoirs.  

National Technical Information Service (NTIS)

The objective of our search is to develop a mechanistic simulation tool by adapting UTCHEM to model the wettability alteration in both conventional and naturally fractured reservoirs. This will be a unique simulator that can model surfactant floods in nat...

2007-01-01

193

Wettability and adsorption characteristics of crude-oil asphaltene and polar fractions  

SciTech Connect

This study relates the chemical composition of the polar compounds of crude oil to the wettability of rock/oil/brine systems. Adsorption properties of polar and asphaltene fractions were evaluated to determine their effects on wettability. Polar compound fractions were found to cause an oil-wet state on Berea sandstone, but the effects were not a function of the polar-fraction concentration. The concentration of nitrogen/sulfur compounds in six crude-oil polar fractions correlated with the wettability of the polar fractions on Berea sandstone. Langmuir-type adsorption on Berea sandstone was observed in adsorption studies of the asphaltene and polar fractions. Additional analysis with brien-saturated Berea sandstone resulted in adsorption values up to three times less than that for dry Berea. The amount of polar fraction adsorbed on brine-saturated berea sandstone correlated with crude-oil wettability.

Crocker, M.E.; Marchin, L.M.

1988-04-01

194

Radiation Induced Surface Activity Phenomenon: 1. Report - Surface Wettability on Metal Oxides  

SciTech Connect

Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. We investigated surface wettability using metal oxides irradiated by gamma rays in room condition. Contact angle, an indicator of macroscopic wettability, was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on oxide metal pieces of titanium, zircaloy No. 4, SUS-304 and copper improved significantly by Radiation Induced Surface Activity (RISA) phenomenon. Highly hydrophilic conditions on the test pieces were achieved after 500 kGy irradiation of {sup 60}Co gamma ray. (authors)

Yasuyuki Imai; Tatsuya Koga; Tomoji Takamasa [Tokyo University of Mercantile Marine, 2-1-6 Etchu-jima, Koto-Ku, Tokyo 135-8533 (Japan); Koji Okamoto [University of Tokyo (Japan); Susumu Uematsu [Advanced Maritime Transport Technology Department, National Maritime Research Institute, Mitaka, Tokyo 181-0004 (Japan)

2002-07-01

195

Wettability and relative permeability of Prudhoe Bay: A case study in mixed-wet reservoirs  

SciTech Connect

This paper describes the variation in wettability and relative permeability at Prudhoe Bay. The authors show that measurements are consistent with recent theories of the relationship between water-saturation, pH, wettability and relative permeability. In particular, the wettability of the reservoir changes from water-wet low on structure near the water/oil contact to mixed-wet behavior higher on structure. Increasing oil-wetting character is correlated to decreasing water saturation. Changes in wettability are also accompanied by changes in water-flood recovery efficiency and are optimum at Amott indices approaching zero. Lithology also impacts recovery efficiency, with more clay-rich rocks having higher residual oil saturations.

Jerauld, G.R.; Rathmell, J.J. [Arco E and P Technology, Plano, TX (United States)

1997-02-01

196

Perfect wettability of carbon by liquid aluminum achieved by a multifunctional flux  

Microsoft Academic Search

The wettability of carbon (graphite and glassy carbon) by liquid aluminum was studied. A special molten salt (flux) system\\u000a was developed under which perfect wettability (a zero contact angle) of liquid aluminum was achieved on carbon surfaces. The\\u000a principal component of the flux is K2TiF6 dissolved in a molten alkali chloride. K2TiF6 is a multifunctional flux component as it performs

P. Baumli; J. Sytchev; G. Kaptay

2010-01-01

197

Wettability of electroless Ni in the under bump metallurgy with lead free solder  

Microsoft Academic Search

This study investigates the wettability of several lead-free solders, including Sn, Sn?Ag, and Sn?Bi, on electroless Ni (EN)\\u000a with various phosphorus content. The role of phosphorus on solder wettability is studied. Microstructure evolution in the\\u000a lead-free solder\\/EN joint is investigated with the aid of electron probe microanalyzer (EPMA) to relate metallurgical reactions\\u000a between the solder and the EN. The SN

Bi-Lian Young; Jenq-Gong Duh; Bi-Shiou Chiou

2001-01-01

198

Adhesion of cultured human endothelial cells onto methacrylate polymers with varying surface wettability and charge  

Microsoft Academic Search

The adhesion of human endothelial cells (HEC) onto a series of well-characterized methacrylate polymer surfaces with varying wettabilities and surface charges was studied either in serum-containing (CMS) or in serum-free (CM) culture medium. HEC adhesion in CMS onto (co)polymers * of hydroxyethyl methacrylate (HEMA) and methyl methacrylate (MMA) was found to be optimal on the moderately wettable copolymer (mol ratio

Wachem van P. B; A. H. Hogt; T. Beugeling; J. Feijen; A. Bantjes; J. P. Detmers; Aken van W. G

1987-01-01

199

Effects of interface wettability on microscale flow by molecular dynamics simulation  

Microsoft Academic Search

Non-equilibrium molecular dynamic simulations have been carried out to study the effect of the interface wettability on the pressure driven flow of a Lennard–Jones (LJ) fluid in a nanochannel. The results show that the hydrodynamic boundary condition at the solid–liquid interface depends on both the interface wettability and the magnitude of the driving force. For a LJ fluid in a

Gyoko Nagayama; Ping Cheng

2004-01-01

200

Correlation of proliferation, morphology and biological responses of fibroblasts on LDPE with different surface wettability  

Microsoft Academic Search

In order to find a correlation between cell adhesion, growth and biological response with different wettability, NIH\\/3T3 fibroblast cells were cultured on plasma-treated low-density polyethylene (LDPE) film generated with radio frequency. Different surface wettabilities (water contact angle 90–40°) were created by varying the duration of plasma treatment between 0 and 15 s, respectively. Growth and proliferation rate of cells on

Soon Hee Kim; Hyun Jung Ha; Youn Kyung Ko; Sun Jung Yoon; John M. Rhee; Moon Suk Kim; Hai Bang Lee; Gilson Khang

2007-01-01

201

Laser pulse dependent micro textured calcium phosphate coatings for improved wettability and cell compatibility  

Microsoft Academic Search

Surface wettability of an implant material is an important criterion in biological response as it controls the adsorption\\u000a of proteins followed by attachment of cells to its surface. Hence, micro-textured calcium phosphate coatings with four length\\u000a scales were synthesized on Ti–6Al–4V substrates by a laser cladding technique and their effects on wettability and cell adhesion\\u000a were systematically evaluated. Microstructure and

Sameer R. Paital; Wei He; Narendra B. Dahotre

2010-01-01

202

In situ surface-modification-induced superhydrophobic patterns with reversible wettability and adhesion.  

PubMed

Herein is described a facile, in situ, ink-regulating approach to rapidly achieve reversible water wettability and adhesion transition, with a large degree of contrast, on superhydrophobic TiO2 nanotube array film. The ink printing and removal process allows the wettability and reversible adhesion transitions to be realized. Experimental results demonstrate the potential application of such site-selective, sticky superhydrophobic patterns for droplet manipulation by in situ surface modification. PMID:23208816

Lai, Yuekun; Pan, Fei; Xu, Cong; Fuchs, Harald; Chi, Lifeng

2012-12-03

203

Some Notes on Wettability and Relative Permeabilities of Carbonate Reservoir Rocks, II  

Microsoft Academic Search

Extensive research work (examination of 161 limestone, dolomitic limestone, calcitic dolomite, and dolomite cores) on wettability of carbonate reservoir rocks by the writers indicate that 15 percent of these rocks are strongly oil-wet (? = 160°-180°; some are bitumen coated), 65 percent are oil-wet (? = 100°-160°), 12 percent have intermediate wettability (? = 80°-100°), and 8 percent are water-wet

George V. Chilingar; T. F. Yen

1983-01-01

204

Wettability and Adsorption Characteristics of Crude-Oil Asphaltene and Polar Fractions  

Microsoft Academic Search

This study relates the chemical composition of the polar compounds of crude oil to the wettability of rock\\/oil\\/brine systems. Adsorption properties of polar and asphaltene fractions were evaluated to determine their effects on wettability. Polar compound fractions were found to cause an oil-wet state on Berea sandstone, but the effects were not a function of the polar-fraction concentration. The concentration

M. E. Crocker; L. M. Marchin

1988-01-01

205

Effects of wettability on three-phase flow in porous media  

Microsoft Academic Search

The authors study the effects of rock wettability on the flow of oil, water, and gas in hydrocarbon reservoirs. The three-phase fluid configurations and displacement processes in a pore of polygonal cross section are described. Initially water-filled, water-wet pores are invaded by oil, representing primary oil migration. Where oil directly contacts the solid surface, the surface will change its wettability.

Mun-Hong Hui; Martin J. Blunt

2000-01-01

206

The Effect of Fluid Shear Stress on Endothelial Cell Adhesiveness to Polymer Surfaces with Wettability Gradient  

Microsoft Academic Search

In this study, the adhesive strength of endothelial cells (ECs) attached on polymer surfaces with different hydrophilicity was investigated using wettability gradient polyethylene (PE) surfaces prepared by corona discharge treatment from a knife-type electrode whose power increases gradually along the sample length. The EC-attached wettability gradient surfaces were mounted on parallel-plate flow chambers in a flow system prepared for cell

Jin Ho Lee; Sang Jin Lee; Gilson Khang; Hai Bang Lee

2000-01-01

207

Wettability of silane-treated glass slides as determined from X-ray photoelectron spectroscopy  

SciTech Connect

The wettability and stability of silane-treated substrates are central in many processes of industrial and environmental interest. Here, the authors bring the capability of X-ray photoelectron spectroscopy (XPS) to bear on the wettability evaluation of treated glass. For a suite of silane-treated slides the authors investigate the relationship between wettability and surface composition as determined from XPS. The adhesion behavior and contact angle of mineral oil on brine-covered surfaces are used here as surface wettability indicators. The XPS spectra of silanes and silane-treated glass slides indicate that silicon species of the kind Si-CH exhibit a well-defined binding energy which differs from that of the Si-O species of the glass. The presence of the Si-CH species reveals glass surfaces that have been rendered hydrophobic by chemisorption of organic matter. The surface carbon content as determined from XPS correlates strongly with the equilibrium contact angle, contact angle hysteresis, adhesion behavior, and wettability state. This correlation can be used to rapidly determine the wettability of treated glass.

Araujo, Y.C.; Toledo, P.G.; Leon, V.; Gonzalez, H.Y. [INTEVEP, S.A., Caracas (Venezuela). Research and Technological Support Center of Petroleos de Venezuela

1995-12-15

208

Coaxial capillary and conductive capillary interfaces for collection of fractions isolated by capillary electrophoresis  

SciTech Connect

An instrument is described that allows the automated collection of fractions isolated by capillary electrophoresis. This instrument allows the electrical connection to be established with the separation capillary by using a coaxial capillary flow cell or by treating the outer surface of the capillary with a gold-filled epoxy to allow electrophoresis. The coaxial interface is most useful when the electroosmotic flow in the capillary is small, and the conductive capillary interface is favored when dilution and contamination of the sample must be minimized. Both geometries permit closely spaced fractions to be acquired with minimal cross-contamination and dilution. Sample recoveries were better than 80% and virtually independent of the chemical characteristics of the sample. Fractions isolated with this instrument were successfully analyzed by high-pressure liquid chromatography and electrospray mass spectrometry. 25 refs., 4 figs.

Chiu, R.W.; Walker, K.L.; Hagen, J.J.; Monning, C.A.; Wilkins, C.L. [Univ. of California, Riverside, CA (United States)

1995-11-15

209

Capillary-driven self-assembly of microchips on oleophilic/oleophobic patterned surface using adhesive droplet in ambient air  

NASA Astrophysics Data System (ADS)

This letter describes a capillary-driven self-assembly technique using oleophilic/oleophobic patterned surface and adhesive in ambient air environment. We use a topographical microstructure of porous ormocer functionalized with a fluorinated trichlorosilane for the oleophobic area and gold patterns for the oleophilic area. The resulted oleophilic/oleophobic patterns show significant wettability contrast for adhesive (Delo 18507), with a contact angle of 119° on oleophobic part and 53° on the oleophilic part. Self-alignment of SU-8 microchips on the oleophilic/oleophobic patterns has been demonstrated. The results provide a promising solution for self-alignment of microparts using commercial adhesives in ambient air environment.

Chang, Bo; Sariola, Veikko; Aura, Susanna; Ras, Robin H. A.; Klonner, Maria; Lipsanen, Harri; Zhou, Quan

2011-07-01

210

Critical capillary channel flow  

NASA Astrophysics Data System (ADS)

The main subject are numerical studies on capillary channel flow, based on results of the sounding rocket experiments TEXUS 41/42. The flow through a capillary channel is established by a gear pump at the outlet. The channel, consists of two parallel glass plates with a width of 25 mm, a gap of 10 mm and a length of 12 mm. The meniscus of a compensation tube maintains a constant system pressure. Steady and dynamic pressure effects in the system force the surfaces to bend inwards. A maximum flow rate is achieved when the free surface collapses and gas ingestion occurs at the outlet. This critical flow rate depends on the channel geometry, the flow regime and the liquid properties. The aim of the experiments is the determination of the free surface shape and to find the maximum flow rate. In order to study the unsteady liquid loop behaviour, a dimensionless transient model was developed. It is based on the unsteady Bernoulli equation, the unsteady continuity equation and geometrical conditions for the surface curvature and the flow cross-section. The pressure is related to the curvature of the free liquid surface by the dimensionless Gauss-Laplace equation with two principal radii. The experimental and evaluated contour data shows good agreement for a sequence of transient flow rate perturbations. The surface oscillation frequencies and amplitudes can be predicted with quite high accuracy. The dynamic of the pump is defined by the increase of the flow rate in a time period. To study the unsteady system behavior in the "worst case", we use a perturbations related to the natural frequency of the oscillating liquid. In the case of steady flow at maximum flow rate, when the "choking" effect occurs, the surfaces collapse and cause gas ingestion into the channel. This effect is related to the Speed Index. At the critical flow rate the Speed Index reaches the value Sca = 1, in analogy to the Mach Number. Unsteady choking does not necessarily cause surface collapse. We show, that temporarily Speed Index values exceeding One may be achieved for a perfectly stable supercritical dynamic flow. As a supercritical criterion for the dynamic free surface stability we define a Dynamic Index D considering the local capillary pressure and the convective pressure, which is a function of the local velocity. The Dynamic Index is below One for stable flow while D = 1 indicates surface collapse. This studies result in a stability diagram, which defines the limits of flow dynamics and the maximum unsteady flow rate. It may serve as a road map for open capillary channel flow control.

Grah, Aleksander; Klatte, Jörg; Dreyer, Michael E.

211

Capillary electrochromatography of cannabinoids.  

PubMed

The applicability of capillary electrochromatography (CEC) with photodiode array UV detection for the analysis of cannabinoids is presented. Baseline separation of seven cannabinoids (cannabigerol, cannabidiol, cannabinol, delta-9-tetrahydrocannabinol, delta-8-tetrahydrocannabinol, cannabichromene, delta-9-tetrahydrocannabinolic acid) is obtained using a 3-micron CEC Hypersil C18 capillary with an acetonitrile/phosphate (pH 2.57) mobile phase. The effects of acetonitrile concentration, buffer concentration, voltage, temperature, stationary phase, and column length on the separation of the cannabinoids were investigated. Good short- and long-term precision in retention times are observed, with significant improvement obtained using relative retention times with cannabinol as reference compound. Although short- and long-term peak area precisions are poor, satisfactory reproducibility is obtained using relative peak areas with cannabinol as reference compound. The applicability of the CEC methodology to drug seizures was demonstrated on marijuana and hashish. Using a high-sensitivity UV flow cell with an extended path length of 1.2 mm, concentration sensitivities approaching HPLC were obtained. PMID:11013726

Lurie, I S; Meyers, R P; Conver, T S

1998-08-01

212

On Capillary Rise and Nucleation  

ERIC Educational Resources Information Center

A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)

Prasad, R.

2008-01-01

213

Capillary electrophoresis in clinical chemistry  

Microsoft Academic Search

Since its introduction, capillary electrophoresis has diversified, spreading out into different specialized fields covering solutions for almost any analytical questions arising in research laboratories. In the context of clinical chemistry, results must be provided at low costs and in a clinically relevent time frame; however, the attributes which have made capillary electrophoresis such a successful tool in basic research are

Rainer Lehmann; Wolfgang Voelter; Hartmut M. Liebich

1997-01-01

214

Functional Reactivity of Cerebral Capillaries  

PubMed Central

The spatiotemporal evolution of cerebral microcirculatory adjustments to functional brain stimulation is the fundamental determinant of the functional specificity of hemodynamically weighted neuroimaging signals. Very little data, however, exist on the functional reactivity of capillaries, the vessels most proximal to the activated neuronal population. Here, we used two-photon laser scanning microscopy, in combination with intracranial electrophysiology and intravital video microscopy, to explore the changes in cortical hemodynamics, at the level of individual capillaries, in response to steady-state forepaw stimulation in an anesthetized rodent model. Overall, the microcirculatory response to functional stimulation was characterized by a pronounced decrease in vascular transit times (20 ± 8 %); a dilatation of the capillary bed (10.9 ± 1.2 %), and significant increases in red blood cell speed (33.0 ± 7.7 %) and flux (19.5 ± 6.2 %). Capillaries dilated more than the medium caliber vessels, indicating a decreased heterogeneity in vessel volumes and increased blood flow carrying capacity during neuronal activation relative to baseline. Capillary dilatation accounted for an estimated ~18 % of the total change in the focal cerebral blood volume. In support of a capacity for focal redistribution of microvascular flow and volume, significant, though less frequent, local stimulation-induced decreases in capillary volume and erythrocyte speed and flux also occurred. The present findings provide further evidence of a strong functional reactivity of cerebral capillaries and underscore the importance of changes in the capillary geometry in the hemodynamic response to neuronal activation.

Stefanovic, B.; Hutchinson, E.; Yakovleva, V.; Schram, V.; Russell, J.T.; Belluscio, L.; Koretsky, A.P.; Silva, A.C.

2011-01-01

215

On Capillary Rise and Nucleation  

ERIC Educational Resources Information Center

|A comparison of capillary rise and nucleation is presented. It is shown that both phenomena result from a balance between two competing energy factors: a volume energy and a surface energy. Such a comparison may help to introduce nucleation with a topic familiar to the students, capillary rise. (Contains 1 table and 3 figures.)|

Prasad, R.

2008-01-01

216

Application of confocal laser scanning microscopy (CLSM) to visualize the effect of porous media wettability on unsaturated pore water configuration  

Microsoft Academic Search

Purpose  Wettability affects water configuration and thereby transport processes and microbial activity in soil. Approaches to visualize\\u000a the effect of porous media wettability on water films surrounding particles are rarely available in the literature. The aim\\u000a of this study is therefore (1) to visualize the effect of wettability on area and connectivity of the water phase and (2)\\u000a to develop a

Gawan Jacob Hilma Müehl; Joerg Rüehlmann; Marc-Oliver Goebel; Joerg Bachmann

217

Surface wettability of titania thin films with increasing Nb content  

NASA Astrophysics Data System (ADS)

TiO2 and TiO2/Nb amorphous thin films were grown on glass substrates by a sol-gel technique (spin coating). Films' surface composition, structure, and morphology were derived from x-ray photoelectron spectroscopy, x-ray diffraction, and atomic force microscopy data. The investigated films showed a smooth surface (roughness values below 5 nm). A separate surface wettability investigation showed that by increasing the Nb amount in pristine titania films results in a decrease of contact angle (CA) values from 40° to nearly 0°, thus, indicating a super-hydrophilic conversion under UV illumination. This conversion rate is greatly enhanced by increasing the Nb content, the surface super-hydrophilic behavior occurring after a couple of minutes in the TiO2/Nb samples, but after 4 h in the pristine titania specimen. The current results are discussed in terms of the optical band gap shift towards higher energies, by increasing the Nb content in the films, a process explained based on small polaron hopping model.

Mardare, Diana; Yildiz, Abdullah; Girtan, Mihaela; Manole, Alina; Dobromir, Marius; Irimia, Mihaela; Adomnitei, Catalin; Cornei, Nicoleta; Luca, Dumitru

2012-10-01

218

AFM study of mineral wettability with reservoir oils.  

PubMed

Wettability plays a key role in determining fluid distributions and consequently the multiphase flow and transport in petroleum reservoirs. Many crude oils have polar organic components that collect at oil-water interfaces and can adsorb onto the mineral surface if the brine film breaks, rendering the medium oil-wet or mixed-wet. Mica and silica surfaces have been aged with brine and crude oils to induce oil component adsorption. Bulk oil is eventually replaced by water in these experiments by washing with common solvents without ever drying the mineral surface. The organic deposit on the mineral surface is studied by atomic force microscopy in the tapping mode under water. Drying the surface during the removal of bulk oil induces artifacts; it is essential to keep the surface wet at all times before atomic force microscopy or contact angle measurement. As the mean thickness of the organic deposit increases, the oil-water contact angle increases. The organic deposits left behind after extraction of oil by common aromatic solvents used in core studies, such as toluene and decalin, are thinner than those left behind by non-aromatic solvents, such as cyclohexane. The force of adhesion with a probe sphere for minerals aged with just the asphaltene fraction is similar to that of the whole oil. The force of adhesion for the minerals aged with just the resin fraction is the highest of all SARA (saturates, aromatics, resins, and asphaltenes) fractions. PMID:16009229

Kumar, K; Dao, E; Mohanty, K K

2005-09-01

219

Influence of variable substrate geometry on wettability and cellular responses.  

PubMed

In this report, we evaluate the impact of a systematic change to the extracellular environment on cell morphology and functionality by combining the inherent properties of biocompatible polymers such as polydimethylsiloxane and polycaprolactone with a specific surface response. By microstructuring pillars and pits on the substrates, varying spacing and height of the structures, we investigate the role of topography in fibroblast cell adhesion and viability. The change of wetting behaviour was tailored and evaluated in terms of contact angle measurements. It was shown that the range of micro-scale physical cues at the interface between the cells and the surrounding environment affects cell shape and migrations, indicating a tendency to respond differently to higher features of the micro-scale. We found that surface topography seems dominant over material wettability, fibroblasts responded to variations in topography by altering morphology and migrating along the direction of spacing among the features biased by the height of structures and not by the material. It is therefore possible to selectively influence either cell adhesion or morphology by choosing adequate topography of the surface. This work can impact in the design of biomaterials and can be applied to implanted biomedical devices, tissue engineering scaffolds and lab on chip devices. PMID:23270757

Cortese, Barbara; Riehle, Mathis O; D'Amone, Stefania; Gigli, Giuseppe

2012-12-05

220

Surface wettability plays a significant role in gecko adhesion underwater  

PubMed Central

Although we now have thousands of studies focused on the nano-, micro-, and whole-animal mechanics of gecko adhesion on clean, dry substrates, we know relatively little about the effects of water on gecko adhesion. For many gecko species, however, rainfall frequently wets the natural surfaces they navigate. In an effort to begin closing this gap, we tested the adhesion of geckos on submerged substrates that vary in their wettability. When tested on a wet hydrophilic surface, geckos produced a significantly lower shear adhesive force (5.4 ± 1.33 N) compared with a dry hydrophilic surface (17.1 ± 3.93 N). In tests on an intermediate wetting surface and a hydrophobic surface, we found no difference in shear adhesion between dry and wet contact. Finally, in tests on polytetrafluoroethylene (PTFE), we found that geckos clung significantly better to wet PTFE (8.0 ± 1.09 N) than dry PTFE (1.6 ± 0.66 N). To help explain our results, we developed models based on thermodynamic theory of adhesion for contacting surfaces in different media and found that we can predict the ratio of shear adhesion in water to that in air. Our findings provide insight into how geckos may function in wet environments and also have significant implications for the development of a synthetic gecko mimic that retains adhesion in water.

Stark, Alyssa Y.; Badge, Ila; Wucinich, Nicholas A.; Sullivan, Timothy W.; Niewiarowski, Peter H.; Dhinojwala, Ali

2013-01-01

221

Physiological factors influencing capillary growth.  

PubMed

(1) Angiogenesis (growth of new capillaries from an existing capillary bed) may result from a mismatch in microvascular supply and metabolic demand (metabolic error signal). Krogh examined the distribution and number of capillaries to explore the correlation between O(2) delivery and O(2) consumption. Subsequently, the heterogeneity in angiogenic response within a muscle has been shown to reflect either differences in fibre type composition or mechanical load. However, local control leads to targetted angiogenesis in the vicinity of glycolytic fibre types following muscle stimulation, or oxidative fibres following endurance training, while heterogeneity of capillary spacing is maintained during ontogenetic growth. (2) Despite limited microscopy resolution and lack of specific markers, Krogh's interest in the structure of the capillary wall paved the way for understanding the mechanisms of capillary growth. Angiogenesis may be influenced by the response of perivascular or stromal cells (fibroblasts, macrophages and pericytes) to altered activity, likely acting as a source for chemical signals modulating capillary growth such as vascular endothelial growth factor. In addition, haemodynamic factors such as shear stress and muscle stretch play a significant role in adaptive remodelling of the microcirculation. (3) Most indices of capillarity are highly dependent on fibre size, resulting in possible bias because of scaling. To examine the consequences of capillary distribution, it is therefore helpful to quantify the area of tissue supplied by individual capillaries. This allows the spatial limitations inherent in most models of tissue oxygenation to be overcome generating an alternative approach to Krogh's tissue cylinder, the capillary domain, to improve descriptions of intracellular oxygen diffusion. PMID:20946238

Egginton, S

2011-07-01

222

Capillaries for use in a multiplexed capillary electrophoresis system  

DOEpatents

The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification ("base calling") is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations.

Yeung, Edward S. (Ames, IA); Chang, Huan-Tsang (Silver Spring, MD); Fung, Eliza N. (Ames, IA)

1997-12-09

223

Electrochromatographic Methods: Capillary Electrochromatograpy  

NASA Astrophysics Data System (ADS)

Capilary electrochromatography is a separation technique that brings together advantages of liquid chromatographic selectivity with high efficiency of CE provided by flat flow profile of the electroosmosis. This chapter provides the basic knowledge on generation of the EOF in capillary electrochromatography and parameters that influence it. Furthermore, attention is paid to the methods used for gradient elution in CEC, which have been one of the problems that restrict the wide use of CEC in chemical laboratories. The chapter also describes the problem of bubble formation in CEC and provides a step-by-step guide of how to perform CEC separation. Moreover, methods of preparation of CEC columns are discussed, including preparation of packed and monolithic silica and polymeric beds. The position of CEC among other contemporary separation methods is also discussed.

Szumski, Micha?

224

Crystal growth from the melt by capillary shaping techniques  

NASA Astrophysics Data System (ADS)

A method based on the Lyapunov stability theory has been developed for studying the stability of crystallization by capillary shaping techniques (including Czochralski, Stepanov, EFG, Verneuil and floating zone methods). The preliminary results of the analysis of stability shows that the crystallization by capillary shaping technique under microgravitation conditions is more stable in some cases than under the action of gravitation. To get deeper into details of the capillary shaping technique under microgravitation conditions, we have carried out model experiments using two immiscible liquids of equal density and crystallization of sapphire in terrestrial conditions with small Bond number. The experiments on the copper crystallization were realized in the high-altitude rockets. Our experiments on indium crystallization carried out in the orbital space probe “Salyut” yielded cylindrical specimens.

Ossipyan, Y. A.; Tatarchenko, V. A.

225

Surface tension drawing of liquid from microplate capillary wells.  

PubMed

Pressure differentials are routinely used to actuate flow in capillaries. We advance here an alternative means of flow generation that capitalizes on the extension of a liquid bridge achieved by the drawing of a rod through the action of surface tension. This meets the exigencies of creating controllable flow using simpler and more compact means. We found the ability to generate controllable flow to be strongly affected by the liquid bridge sustaining features, and that the use of rod diameters larger than the capillary was more conducive. The extensional flow resulting from the rupture of the liquid bridge was also found to have a strong circulation component which facilitated mixing. The approach here is highly amenable for use in capillary well microplates which have significant advantages over standard microplates. The features of this approach offer usage possibilities in biochemical applications in the field, such as in the leukocyte cell adhesion and hemagglutination tests of blood samples. PMID:21986403

Schwalb, Willem; Ng, Tuck Wah; Lye, Jonathan Kok Keung; Liew, Oi Wah; Cheong, Brandon Huey-Ping

2011-09-19

226

Double Emulsions through Wettability Control in PDMS Microfluidic Devices  

NASA Astrophysics Data System (ADS)

Hydrodynamic Flow Focusing allows for the well-controlled production of monodisperse double and multiple emulsions. While this method of emulsification is well described for glass capillary devices, it has not yet been developed for PDMS devices that are readily accessible using soft-lithography. The reason is the difficulty of spatially controlling the wetting behavior of PDMS microchannels. We will present a novel technique of photopatterning that allows for the production of double emulsions in PDMS devices. Moreover, owing to an optimized setup, smaller droplets may be made down to a size range that was not accessible using the conventional approaches.

Holtze, Christian; Mele, Elisa; Weitz, David

2007-03-01

227

Effects of initial surface wettability on biofilm formation and subsequent settlement of Hydroides elegans.  

PubMed

Hydroides elegans is a major fouling organism in tropical waters around the world, including Pearl Harbor, Hawaii. To determine the importance of initial surface characteristics on biofilm community composition and subsequent colonization by larvae of H. elegans, the settlement and recruitment of larvae to biofilmed surfaces with six different initial surface wettabilities were tested in Pearl Harbor. Biofilm community composition, as determined by a combined approach of denaturing gradient gel electrophoresis and fluorescence in situ hybridization, was similar across all surfaces, regardless of initial wettability, and all surfaces had distinct temporal shifts in community structure over a 10 day period. Larvae settled and recruited in higher numbers to surfaces with medium to low wettability in both May and August, and also to slides with high wettability in August. Pearl Harbor biofilm communities developed similarly on a range of surface wettabilities, and after 10 days in Pearl Harbor all surfaces were equally attractive to larvae of Hydroides elegans, regardless of initial surface properties. PMID:19306143

Huggett, Megan J; Nedved, Brian T; Hadfield, Michael G

2009-01-01

228

Integrated multiplexed capillary electrophoresis system  

DOEpatents

The present invention provides an integrated multiplexed capillary electrophoresis system for the analysis of sample analytes. The system integrates and automates multiple components, such as chromatographic columns and separation capillaries, and further provides a detector for the detection of analytes eluting from the separation capillaries. The system employs multiplexed freeze/thaw valves to manage fluid flow and sample movement. The system is computer controlled and is capable of processing samples through reaction, purification, denaturation, pre-concentration, injection, separation and detection in parallel fashion. Methods employing the system of the invention are also provided.

Yeung, Edward S. (Ames, IA); Tan, Hongdong (Ames, IA)

2002-05-14

229

Small capillary pumped AMTEC systems  

NASA Astrophysics Data System (ADS)

Alkali Metal Thermoelectric Converter (AMTEC) systems offer significant potential advantages for space power. Recent experiments have shown that electromagnetic pumps can operate with a negative priming head and so may be suitable for space applications in microgravity (Hunt et al. 1992). Capillary pumped cells offer an alternative approach to microgravity compatibility. We have designed, built, and operated capillary pumped AMTEC cells in various orientations with respect to gravity in order to provide a presumptive demonstration of zero-G capability (Sievers et al. 1992). We report lifetime and performance data for these capillary pumped AMTEC cells. Progress on other issues relating to space flight testing of AMTEC systems is also discussed.

Hunt, Thomas K.; Sievers, Robert K.; Butkiewicz, David A.; Pantolin, Jan E.; Ivanenok, Joseph F.

1993-01-01

230

Note on Evaporation in Capillaries.  

National Technical Information Service (NTIS)

Factors are discussed which govern evaporation of liquid in small capillaries of greatly varying bore, such as might be encountered in porous media. If the escape of the vapor is relatively unobstructed, marked temperature gradients are found to be confin...

R. E. Meyer

1983-01-01

231

Electromagnetic Activation of Capillary Switches  

NASA Astrophysics Data System (ADS)

By designing coupled droplet pairs with the appropriate length scale to promote surface tension as the dominant force, one can create bi-stable capillary switches. This bi-stability can be triggered by pressure pulses, surface chemistry, electroosmosis, or body forces. To exploit the latter, we designed a capillary switch with electromagnetic activation. The resulting setup consists of a sub-millimeter tube, overfilled with a ferrofluid, surrounded by a wire coil to generate a magnetic field. Evidence of this capillary switching will be presented along with some theoretical basis in fluid- and electro-dynamics. The approach may also be used to investigate other transport phenomena in electromagnetically-coupled microfluidic systems, including the relative effects of translational motion of the ferrofluid (both particles and solvent molecules) versus the rotational effects of the individual magnetic grains. These individually addressable capillary switches offer intriguing applications including high-speed adaptive optics, actuators at the microscale, and possible PCB integration.

Malouin, Bernie; Dayal, Rohan; Parsa, Leila; Hirsa, Amir

2008-11-01

232

DNA typing by capillary electrophoresis  

SciTech Connect

Capillary electrophoresis is becoming more and more important in nucleic acid analysis including DNA sequencing, typing and disease gene measurements. This work summarized the background of DNA typing. The recent development of capillary electrophoresis was also discussed. The second part of the thesis showed the principle of DNA typing based on using the allelic ladder as the absolute standard ladder in capillary electrophoresis system. Future work will be focused on demonstrating DNA typing on multiplex loci and examples of disease diagnosis in the on-line format of PCR-CE. Also capillary array electrophoresis system should allow high throughput, fast speed DNA typing. Only the introduction and conclusions for this report are available here. A reprint was removed for separate processing.

Zhang, N.

1997-10-08

233

Capillary Fracturing in Granular Media  

NASA Astrophysics Data System (ADS)

We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and “capillary fracturing,” where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks.

Holtzman, Ran; Szulczewski, Michael L.; Juanes, Ruben

2012-06-01

234

Capillary fracturing in granular media.  

PubMed

We study the displacement of immiscible fluids in deformable, noncohesive granular media. Experimentally, we inject air into a thin bed of water-saturated glass beads and observe the invasion morphology. The control parameters are the injection rate, the bead size, and the confining stress. We identify three invasion regimes: capillary fingering, viscous fingering, and "capillary fracturing," where capillary forces overcome frictional resistance and induce the opening of conduits. We derive two dimensionless numbers that govern the transition among the different regimes: a modified capillary number and a fracturing number. The experiments and analysis predict the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural processes such as primary oil migration, methane venting from lake sediments, and the formation of desiccation cracks. PMID:23004989

Holtzman, Ran; Szulczewski, Michael L; Juanes, Ruben

2012-06-28

235

UV/thermally driven rewritable wettability patterns on TiO2-PDMS composite films.  

PubMed

Composite films of TiO2 and polydimethylsiloxane (PDMS) are prepared by a sol-gel method, cured with UV irradiation, and then treated in hot water to crystallize the TiO2 in the film. The presence of anatase TiO2 contributes to the photoinduced superhydrophilicity of the film under UV irradiation. Contact angle studies reveal that the TiO2-PDMS composite film recovers its original hydrophobic state. Hydrophobic-superhydrophilic patterns are successfully formed on the films. The wettability patterns can be erased by UV irradiation and thermal treatment. New wettability patterns can be reconstructed, demonstrating that the film exhibits rewritable wettability without the need for organic chemicals. PMID:20712336

Nakata, Kazuya; Kimura, Hiroaki; Sakai, Munetoshi; Ochiai, Tsuyoshi; Sakai, Hideki; Murakami, Taketoshi; Abe, Masahiko; Fujishima, Akira

2010-09-01

236

WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS  

SciTech Connect

This report summarizes the experimental results of some baseline imbibition tests on recovery of mineral oil at very strongly water wet conditions (VSWW) from sandstones with air permeability ranging from 80 to 360 md. Mixed wettability cores were prepared by adsorption from either Minnelusa or Gullfaks crude oil using either synthetic Minnelusa reservoir brine or sea water. Recovery of two synthetic-based mud (SBM) base oils, Petrofree(reg sign)SF and LVT 200 from mixed wettability cores gave results that correlated closely with results for refined oils with viscosities ranging from 3.8 to 84 cp. Two synthetic-based mud emulsifiers (LE SUPERMUL and EZ MUL(reg sign)NT) were added to mineral oil and tested for their effect on the wettability of MXW-F core samples as indicated by spontaneous imbibition. In both cases a significant decrease in water wetness was obtained.

Jill S. Buckley; Norman R. Morrow

2003-05-01

237

Characteristics of Electrically Switchable Wettability Surfaces of Liquid Crystal and Polymer Composite Films  

NASA Astrophysics Data System (ADS)

Experimentally, the electrically controllable surface wettability of liquid crystal and polymer composite film has been demonstrated. In the work, scanning probe microscopy has been used to investigate the surface characterization of liquid crystal molecular units at a polymer surface under external voltages applied. The surface morphologies as well as the sensitivity of measurement to surface adhesive force on the nanoscale are determined quantitatively for such unique nano-sized liquid crystals/polymer composite films. The surface wettability of the films deduced from the local adhesion properties demonstrated the electrical control of surface wettability properties, suggesting that the interfacial liquid-crystal molecular alignment of the films with external voltage applied should have significant influence on the modification of the surface characterization of liquid crystals.

Ya-Ping Chiu,; Cheng-Yu Shen,; Yi-Hsin Lin,

2010-07-01

238

Wettability Alteration of Porous Media to Gas-Wetting for Improving Productivity and Injectivity in Gas-Liquid Flows.  

National Technical Information Service (NTIS)

Wettability alteration to intermediate gas-wetting in porous media by treatment with FC-759, a fluoropolymer polymer, has been studied experimentally. Berea sandstone was used as the main rock sample in our work and its wettability before and after chemic...

2003-01-01

239

Effect of veneer side wettability on bonding quality of Eucalyptus globulus plywoods prepared using a tannin–phenol–formaldehyde adhesive  

Microsoft Academic Search

The influence of rotary peeling on the different behaviour of tight and loose sides of Eucalyptus globulus veneers has been studied. The presence of lathe checks on the loose sides favours wettability, the contact angle decreasing more rapidly on these sides than on tight sides. Additionally, pine bark tannins improved wettability due to their surfactant character. Bonding quality tests carried

G. Vázquez; J. González-Álvarez; F. López-Suevos; G. Antorrena

2003-01-01

240

Capillary viscometry of sodium soaps  

Microsoft Academic Search

Summary The rheological properties of a sodium tallow-coconut oil soap (15% water) have been determined using a high pressure capillary extrusion viscometer over shear rates of 14.7 to 2560 sec?1 and temperatures of 70–103°C. Capillary flow measurements were also made on sodium stearate (25% water) at 90°C. The data indicated shear thinning characteristics and were fitted to an equation of

John E. Bujake

1966-01-01

241

Gradient elution in capillary electrochromatography  

Microsoft Academic Search

In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically-driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with sub-mL\\/min flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and

D. S. Anex; D. J. Rakestraw; Chao Yan; R. Dadoo; R. N. Zare

1997-01-01

242

Wettability, FTIR and dielectric studies of 1,4-dioxane and water system.  

PubMed

Wettability studies are of importance for electronic devices. Various methods are known to convert the hydrophobic substrates to hydrophilic substrates, but the studies on the relative dependence of wettability with varying concentrations of an aqueous system are meager. The wetting of different substrates with varying concentration of 1,4-dioxane in water is investigated and the results of concentration dependence of wetting are presented. The FTIR spectrum shows a blue shift of the OH peak--a feature typical of aqueous-1,4-dioxane systems. Concentration dependence of dielectric permittivity of this system also showed an anomaly. PMID:21345449

Madhurima, V; Purkayastha, Debarun Dhar; Rao, N V S

2011-02-02

243

Local wettability modification by thermochemical nanolithography with write-read-overwrite capability  

NASA Astrophysics Data System (ADS)

The wettability of a thin polymer film was modified twice by thermochemical nanolithography. By means of a first local chemical modification induced by an atomic force microscope tip heated to 110+/-20 °C, hydrophilic patterns are written over an originally hydrophobic polymer surface. By further heating to 190+/-20 °C, a second chemical modification reverses the local wettability change introduced by the first chemical modification. This write-read-overwrite capability can be particularly useful in the design of complex nanofluidic devices.

Wang, D. B.; Szoszkiewicz, R.; Lucas, M.; Riedo, E.; Okada, T.; Jones, S. C.; Marder, S. R.; Lee, J.; King, W. P.

2007-12-01

244

WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS  

SciTech Connect

The objectives of this project are: (1) to improve understanding of the wettability alteration of mixed-wet rocks that results from contact with the components of synthetic oil-based drilling and completion fluids formulated to meet the needs of arctic drilling; (2) to investigate cleaning methods to reverse the wettability alteration of mixed-wet cores caused by contact with these SBM components; and (3) to develop new approaches to restoration of wetting that will permit the use of cores drilled with SBM formulations for valid studies of reservoir properties.

Jill S. Buckley; Norman R. Morrow

2006-01-01

245

Pulsatility of Parafoveal Capillary Leukocytes  

PubMed Central

The use of adaptive optics (AO) in a confocal scanning laser ophthalmoscope (AOSLO) allows for long-term imaging of parafoveal capillary leukocyte movement and measurement of leukocyte velocity without contrast dyes. We applied the AOSLO to investigate the possible role of the cardiac cycle on capillary leukocyte velocity by directly measuring capillary leukocyte pulsatility. The parafoveal regions of 8 eight normal healthy subjects with clear ocular media were imaged with an AOSLO. All subjects were dilated and cyclopleged. The AOSLO field of view was either 1.4 × 1.5 degrees or 2.35 × 2.5 degrees, the imaging wavelength was 532 nm and the frame rate was 30 fps. A photoplethysmograph was used to record the subject’s pulse synchronously with each AOSLO video. Parafoveal capillary leukocyte velocities and pulsatility were determined for two or three capillaries per subject. Leukocyte velocity and pulsatility were determined for all eight subjects. The mean parafoveal capillary leukocyte velocity for all subjects was Vmean = 1.30 mm/sec (SD = +/? 0.40 mm/sec). There was a statistically significant difference between leukocyte velocities, Vmax and Vmin, over the pulse cycle for each subject (p<0.05). The mean pulsatility was Pmean= 0.45 (+/? 0.09). Parafoveal capillary leukocyte pulsatility can be directly and non-invasively measured without the use of contrast dyes using an AOSLO. A substantial amount of the variation found in leukocyte velocity is due to the pulsatility that is induced by the cardiac cycle. By controlling for the variation in leukocyte velocity caused by the cardiac cycle, we can better detect other changes in retinal leukocyte velocity induced by disease or pharmaceutical agents.

Martin, Joy A.; Roorda, Austin

2009-01-01

246

Western Blotting using Capillary Electrophoresis  

PubMed Central

A microscale Western blotting system based on separating sodium-dodecyl sulfate protein complexes by capillary gel electrophoresis followed by deposition onto a blotting membrane for immunoassay is described. In the system, the separation capillary is grounded through a sheath capillary to a mobile X-Y translation stage which moves a blotting membrane past the capillary outlet for protein deposition. The blotting membrane is moistened with a methanol and buffer mixture to facilitate protein adsorption. Although discrete protein zones could be detected, bands were broadened by ~1.7-fold by transfer to membrane. A complete Western blot for lysozyme was completed in about one hour with 50 pg mass detection limit from low microgram per milliliter samples. These results demonstrate substantial reduction in time requirements and improvement in mass sensitivity compared to conventional Western blots. Western blotting using capillary electrophoresis shows promise to analyze low volume samples with reduced reagents and time, while retaining the information content of a typical Western blot.

Anderson, Gwendolyn J.; Cipolla, Cynthia; Kennedy, Robert T.

2011-01-01

247

Boiling Heat Transfer Characteristics with Highly Wettable Heated Surface under Forced Convection Conditions  

Microsoft Academic Search

Under forced convection and atmospheric pressure conditions, heat transfer characteristics were studied using an annulus channel of a heater rod with highly-wettable surface. Improvement of phase change heat transfer under boiling and condensation process requires that either liquid heated or vapor cooled can contact a heat transfer surface effectively, but either a vapor layer or a liquid film can be

Toru Mitsutake; Fumihisa Kano; Tetsuo Oosato; Akio Sayano; Miyuki Akiba; Shinichi Morooka

2004-01-01

248

Prospects of improved oil recovery related to wettability and brine composition  

Microsoft Academic Search

Although attention is given to the composition of the injected brine in a waterflood with respect to compatibility with the formation, tests are not usually made to determine its effect on oil recovery. This study shows that the wettability and laboratory waterflood recoveries of crude oil\\/brine\\/rock (COBR) ensembles can be strongly dependent on brine composition and on related COBR interactions.

Norman R. Morrow; Guo-qing Tang; Marc Valat; Xina Xie

1998-01-01

249

Wettability, Oil Recovery, and Interfacial Tension with an SDBS–Dodecane–Kaolin System  

Microsoft Academic Search

The wettability of kaolin with SDBS (sodium dodecyl benzene sulfonate) aqueous solutions was measured by the Washburn equation expressed as contact angles. The contact angle changes for SDBS aqueous solutions on kaolin surface was studied. The interfacial tension between the SDBS solutions and n-dodecane was measured using both drop volume and spinning drop methods. Then the oil recovery of n-dodecane

Zhichu Bi; Zhenshu Zhang; Fei Xu; Yueying Qian; Jiayong Yu

1999-01-01

250

Investigation of wettability by NMR microscopy and spin-lattice relaxation  

SciTech Connect

The wettability of reservoir rock has an important impact on the efficiency of oil recovery processes and the distribution of oil and water within the reservoir. One of the potentially useful tools for wettability measurements is nuclear magnetic resonance (NMR) and spin-lattice relaxation. More recently using NMR microscopy NIPER has developed the capability of imaging one- and two-phase fluid systems in reservoir rock at resolutions to 25 microns. Effects seen in the images of fluids within the pore space of rocks near the rock grain surfaces hinted at the possibility of using NMR microscopy to map the wettability variations at grain sites within the pore space. Investigations were begun using NMR microscopy and spin-lattice relaxation time measurements on rock/fluid systems and on well-defined fractional wet model systems to study these effects. Relaxation data has been modelled using the stretched exponential relationship recently introduced. Comparisons of the NMR microscopy results of the model system with the rock results indicate that the observed effects probably do not reflect actual wettability variations within the pore space. The results of the relaxation time measurements reveal that even in the simple model studied, the behavior of two phases is somewhat ambiguous and much more complex and requires more study.

Doughty, D.A.; Tomutsa, Liviu

1993-11-01

251

New wettability test for chalk based on chromatographic separation of SCN ? and SO 4 2?  

Microsoft Academic Search

Wettability, water-wetness or oil-wetness, is usually defined in terms of the method used to determine the wetting state of a porous medium. In the Amott test, which is most frequently used for porous media, the wetting indices of water and oil are determined by the extent of spontaneous imbibition of water and oil from the state of the corresponding residual

S. Strand; D. C. Standnes; T. Austad

2006-01-01

252

The wettability of coal and its relevance to the control of dust during coal mining  

Microsoft Academic Search

Water sprays are used on longwall mining machines to help control respirable coal dust during underground mining operations. Surfactant reagents added to the sprays, if properly selected, can improve the coal dust wettability and capture efficiency of water droplets. Combining water-soluble polymers with a surfactant can improve dust suppression further by altering the adhesion-cohesion properties of water droplets. The mechanism

H. W. Kilau

1993-01-01

253

Effect of Crude-Oil-Induced Wettability Changes on Oil Recovery  

Microsoft Academic Search

Displacements in strongly water-wet cores are compared with results of similar tests for a mixed wettability condition induced by a selected crude oil. Cores exposed to crude oil showed weakly water-wet imbibition behavior and 30 to 65% improvement in microscopic displacement efficiency. Other characteristics included clean breakthrough and low relative permeability to water at residual oil saturation. Flow visualization experiments

Norman Morrow; Hau Lim; Jill Ward

1986-01-01

254

The impact of wettability and connectivity on relative permeability in carbonates: A pore network modeling analysis  

NASA Astrophysics Data System (ADS)

We use pore network modeling to study the impact of wettability and connectivity on waterflood relative permeability for a set of six carbonate samples. Four quarry samples are studied, Indiana, Portland, Guiting, and Mount Gambier, along with two subsurface samples obtained from a deep saline Middle Eastern aquifer. The pore space is imaged in three dimensions using X-ray microtomography at a resolution of a few microns. The images are segmented into pore and solid, and a topologically representative network of pores and throats is extracted from these images. We then simulate quasi-static displacement in the networks. We represent mixed-wet behavior by varying the oil-wet fraction of the pore space. The relative permeability is strongly dependent on both the wettability and the average coordination number of the network. We show that traditional measures of wettability based on the point where the relative permeability curves cross are not reliable. Good agreement is found between our calculations and measurements of relative permeability on carbonates in the literature. This work helps establish a library of benchmark samples for multiphase flow and transport computations. The implications of the results for field-scale displacement mechanisms are discussed, and the efficiency of waterflooding as an oil recovery process in carbonate reservoirs is assessed depending on the wettability and pore space connectivity.

Gharbi, Oussama; Blunt, Martin J.

2012-12-01

255

Characterization of Mixed Wettability at Different Scales and its Impact on Oil Recovery Efficiency.  

National Technical Information Service (NTIS)

The objectives of this project was to: (1) quantify the pore scale mechanisms that determine the wettability state of a reservoir, (2) study the effect of crude oil, brine and mineral compositions in the establishment of mixed wet states, (3) clarify the ...

M. M. Sharma G. J. Hirasaki

2002-01-01

256

Roughness induced dynamic changes of wettability of acid etched titanium implant modifications  

Microsoft Academic Search

Dynamic contact angle analysis (DCA) was used to investigate time-dependent wettability changes of sandblasted and acid-etched commercially pure (cp) titanium (Ti) implant modifications during their initial contact with aqueous systems compared to a macrostructured reference surface. Surface topography was analyzed by scanning electron microscopy and by contact stylus profilometry. The microstructured Ti surfaces were found to be initially extremely hydrophobic.

F. Rupp; L. Scheideler; D. Rehbein; D. Axmann; J. Geis-Gerstorfer

2004-01-01

257

Electronic modulation of an electrochemically induced wettability gradient to control water movement on a polyaniline surface  

Microsoft Academic Search

Wettability gradients can be electronically controlled in a multiple-electrode electrochemical structure that consists of a solid electrolyte and the conducting polymer polyaniline doped with dodecylbenzenesulfonic acid as the active surface. A bias applied directly between a counter electrode and the surface to be switched determines the initial water contact angle, while the potential between two electrodes on either side of

Joakim Isaksson; Nathaniel D. Robinson; Magnus Berggren

2006-01-01

258

Fibronectin matrix formation by human fibroblasts on surfaces varying in wettability  

Microsoft Academic Search

The spatial organization of extracellular fibronectin on biomaterial surfaces might be important for interaction with tissue cells. In previous investigations we have demonstrated that hydrophilic materials s bind preadsorbed fibronectin that can easily be reorganized by fibroblasts in a specific matrix-like structure, while on less wettable materials (possessing water contact angles above 60 deg) the cells were unable to do

Georgi Altankov; Thomas Groth

1997-01-01

259

Wettability of substrata controls cell–substrate and cell–cell adhesions  

Microsoft Academic Search

The maintenance of endothelial cell (EC) monolayer architecture requires stable adhesions not only between neighboring cells but also between cells and the extracellular matrix. While the influence of biomaterials surface wettability on cell–substratum adhesion is rather well studied, its impact on cell–cell cohesion has not been extensively investigated. In the present study a model system consisting of hydrophilic and hydrophobic

R. Tzoneva; N. Faucheux; T. Groth

2007-01-01

260

Spray-dried whey protein\\/lactose\\/soybean oil emulsions. 2. Redispersability, wettability and particle structure  

Microsoft Academic Search

In the present paper redispersion and wettability experiments of spray-dried whey protein-stabilized emulsions are presented. Emulsion droplet size after redispersion gives information about eventual coalescence between emulsion droplets in the powder matrix during drying or storage, resulting in an increase in emulsion droplet size after redispersion. Results from redispersion experiments are combined with previously presented knowledge about powder surface composition

Pia Fäldt; Björn Bergenståhl

1996-01-01

261

Thermo-responsive surface wettability on a pristine carbon nanotube film  

Microsoft Academic Search

A superhydrophobic carbon nanotube (CNT) film is fabricated by a simple spray-coating method without any chemical modification. The superhydrophobic surface changes after heating to a state of superhydrophilic wettability, and such transition may be attributed to the change of electronic structures of CNTs since the surface structure and composition after treated remain the same as the pristine CNTs. The initial

Jin Yang; Zhaozhu Zhang; Xuehu Men; Xianghui Xu; Xiaotao Zhu

2011-01-01

262

Interaction of Different Types of Cells on Polymer Surfaces with Wettability Gradient  

Microsoft Academic Search

Gradient surfaces whose properties are changed gradually along the sample length are of particular interest for basic studies of the interaction between biological species and surfaces since the effect of a selected property can be examined in a single experiment on one surface. We prepared a wettability gradient on low density polyethylene (PE) sheets by treating them in air with

Jin Ho Lee; Gilson Khang; Jin Whan Lee; Hai Bang Lee

1998-01-01

263

High-Sensitivity and High-Resolution Contact Hole Patterning by Enhanced-Wettability Developer  

Microsoft Academic Search

We have determined that high-sensitivity and high-resolution contact hole photoresist patterning can be achieved using an optimized combination of developer, added surfactant and ammonium chloride salt. The addition of surfactant improves the wettability of the developer to promote resist dissolution. The presence of ammonium chloride salt protects the sidewall of the contact hole resist pattern to achieve good pattern profile.

Hisayuki Shimada; Shigeki Shimomura; Kouichi Hirose; Tadahiro Ohmi

1993-01-01

264

Influence of the wettability on the electrical response of microporous systems  

NASA Astrophysics Data System (ADS)

The permittivity of different microporous systems, including sintered glass filters, Berea sandstones and reservoir rocks, was measured in the frequency range 102 -1010 Hz. For each system, the natural pore wettability was modified to get two different sets of samples: those strongly oil-wet and those water-wet. The samples were saturated with a hydrocarbon oil and water at different degrees of water content. Dielectric spectra showed a conductivity contribution due to ionic carriers in addition to a Maxwell-Wagner-Sillars relaxation, active up to high frequencies. Because of the dominant role that wettability plays in the electrical response of partially saturated microporous solids, water-wet and oil-wet samples showed remarkable differences in the loss tangent spectra, as well as different times and strengths of the Maxwell-Wagner-Sillars relaxation. The dielectric spectra were analysed by using some standard models for extracting valuable information about the pore wettability. Moreover, the use of impedance measurements for in situ determination of the wettability of reservoir rocks was evaluated.

Capaccioli, S.; Lucchesi, M.; Casalini, R.; Rolla, P. A.; Bona, N.

2000-05-01

265

Contact Lenses Wettability In Vitro: Effect of Surface-Active Ingredients  

PubMed Central

Purpose To investigate the release of surface-active agents (surfactants) from unworn soft contact lenses and their influence on the lens surface wettability in vitro. Methods Surface tension (ST) of blister pack solutions was measured by pendant-drop technique. STs at the air-aqueous interface and contact angles (CAs) of four conventional and seven silicone hydrogel (SiH) soft contact lenses (SCLs) were evaluated in a dynamic-cycling regime using a modified captive-bubble tensiometer-goniometer. Measurements were performed immediately after removal from blister packs, and after soaking in a glass vial filled with a surfactant-free solution, which was replaced daily for one week. Lens surface wettability was expressed as adhesion energy (AE) according to Young’s equation. Results STs of all blister pack solutions were lower than the reference ST of pure water (72.5 mN/m), indicating the presence of surfactants. When lenses were depleted of surfactants by soaking, the STs of all studied lenses and advancing CAs of selected lenses increased (p < 0.001). Receding CAs of all studied lenses were 12° ± 5° and were not affected by the presence of surfactants. For most of the conventional lenses, the surface wettability was largely dependent on surfactants, and reduced significantly after surfactant depletion. In contrast, most SiH lenses exhibited stable and self-sustained surface wettability in vitro. Conclusions The manufacturer-added surfactants affected wetting properties of all studied SCLs, although to different degrees.

Lin, Meng C.; Svitova, Tatyana F.

2010-01-01

266

Paramecium swimming in capillary tube  

NASA Astrophysics Data System (ADS)

Swimming organisms in their natural habitat need to navigate through a wide range of geometries and chemical environments. Interaction with boundaries in such situations is ubiquitous and can significantly modify the swimming characteristics of the organism when compared to ideal laboratory conditions. We study the different patterns of ciliary locomotion in glass capillaries of varying diameter and characterize the effect of the solid boundaries on the velocities of the organism. Experimental observations show that Paramecium executes helical trajectories that slowly transition to straight lines as the diameter of the capillary tubes decreases. We predict the swimming velocity in capillaries by modeling the system as a confined cylinder propagating longitudinal metachronal waves that create a finite pressure gradient. Comparing with experiments, we find that such pressure gradient considerations are necessary for modeling finite sized ciliary organisms in restrictive geometries.

Jana, Saikat; Um, Soong Ho; Jung, Sunghwan

2012-04-01

267

Microbial Enhanced Oil Recovery and Wettability Research Program. Annual report, FY 1991  

SciTech Connect

This report covers research results for fiscal year 1991 for the Microbial Enhanced Oil Recovery (MEOR) and Wettability Research Program conducted by EG&G Idaho, Inc. at the Idaho National Engineering Laboratory ONEL) for the US Department of Energy Idaho Field Office (DOE-ID). The program is funded by the Assistant Secretary of Fossil Energy, and managed by DOE-ID and the Bartlesville Project Office (BPO). The objectives of this multi-year program are to develop MEOR systems for application to reservoirs containing medium to heavy crude oils and to design and implement an industry cost-shared field demonstration project of the developed technology. An understanding of the controlling mechanisms will first be developed through the use of laboratory scale testing to determine the ability of microbially mediated processes to recover oil under reservoir conditions and to develop the design criteria for scale-up to the field. Concurrently with this work, the isolation and characterization of microbial species collected from various locations including target oil field environments is underway to develop more effective oil recovery systems for specific applications. Research focus includes the study of biogenic product and formation souring processes including mitigation and prevention. Souring research performed in FY 1991 also included the development of microsensor probe technology for the detection of total sulfide in collaboration with the Montana State University Center for Interfacial Microbial Process Engineering (CIMPE). Wettability research is a multi-year collaborative effort with the New Mexico Petroleum Recovery Research Center (NMPRRC) at the New Mexico institute of Mining and Technology, Socorro, NM to evaluate reservoir wettability and its effects on oil recovery. Results from the wettability research will be applied to determine if alteration of wettability is a significant contributing mechanism for MEOR systems.

Bala, G.A.; Barrett, K.B.; Eastman, S.L.; Herd, M.D.; Jackson, J.D.; Robertson, E.P.; Thomas, C.P.

1993-09-01

268

Nonsteady Flow in Capillary Tubes  

NASA Astrophysics Data System (ADS)

Surface phenomena in the field of electron devices and the problem of how long. It takes plants to absorb water during their growth in hydroponic cultivation is attraching the attention of riseachers. However, the related study of non-steady flow in capillary tubes has a number of issues that require investigation. In response to this situation, we made attempted to assess nonsteady fiow in capillary tubes, the liquid rise time and other issues, using a motion equation that takes factors including the friction force of the tube and the surface tension into consideration.

Hara, Ayako

2000-03-01

269

Pore-Lining Composition and Capillary Breakthrough Pressure of Mudstone Caprocks: Sealing Efficiency of Geologic CO2 Storage Sites  

NASA Astrophysics Data System (ADS)

Subsurface containment of CO2 is predicated on effective caprock sealing. Many previous studies have relied on macroscopic measurements of capillary breakthrough pressure and other petrophysical properties without direct examination of solid phases that line pore networks and directly contact fluids. However, pore-lining phases strongly contribute to sealing behavior through interfacial interactions among CO2, brine, and the mineral or non-mineral phases. Our high resolution (i.e., sub-micron) examination of the composition of pore-lining phases of several continental and marine mudstones indicates that sealing efficiency (i.e., breakthrough pressure) is governed by pore shapes and pore-lining phases that are not identifiable except through direct characterization of pores. Bulk X-ray diffraction data does not indicate which phases line the pores and may be especially lacking for mudstones with organic material. Organics can line pores and may represent once-mobile phases that modify the wettability of an originally clay-lined pore network. For shallow formations (i.e., < ~800 m depth), interfacial tension and contact angles result in breakthrough pressures that may be as high as those needed to fracture the rock—thus, in the absence of fractures, capillary sealing efficiency is indicated. Deeper seals have poorer capillary sealing if mica-like wetting dominates the wettability. We thank the U.S. Department of Energy’s National Energy Technology Laboratory and the Office of Basic Energy Sciences, and the Southeast and Southwest Carbon Sequestration Partnerships for supporting this work. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

Heath, J. E.; Dewers, T. A.; McPherson, B. J.; Kotula, P. G.

2010-12-01

270

Synergism of capillary isotachophoresis and capillary zone electrophoresis.  

PubMed

The combination of capillary isotachophoresis and capillary zone electrophoresis may enhance greatly the performance of analytical capillary electrophoresis with respect to both separation power and the concentration sensitivity. The concentrating effects and the separation power of isotachophoresis allow the analysis of diluted samples and the elimination of interferences due to bulk components. The separation process of zone electrophoresis enables one to resolve the stack of trace analytes and detect the resulting individual zones with high sensitivity. The transition of isotachophoresis into zone electrophoresis plays the key role in the overall performance of this hyphenated technique. This article describes the dynamics of the conversion of isotachophoresis into zone electrophoretic mode and shows that the key role is played by the segments of the leading and terminating zones from the isotachophoretic stage. The magnitude of these segments directly effects the detection time as well as the separation width of the peaks of analytes. It is shown that these effects are also important in the analyses by capillary zone electrophoresis where isotachophoresis is induced by the sample itself. Finally, the paper presents a list of recommended, user-friendly, electrolyte systems which enable one to simply predict the performance of the combination isotachophoresis-zone electrophoresis. PMID:9061479

Krivánková, L; Bocek, P

1997-02-01

271

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

Yeung, Edward S. (Ames, IA); Taylor, John A. (Nevada, IA)

1994-06-28

272

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figures.

Yeung, E.S.; Taylor, J.A.

1994-06-28

273

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis. 14 figs.

Yeung, E.S.; Taylor, J.A.

1996-03-12

274

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

A fluorescence detection system for capillary electrophoresis is provided wherein the detection system can simultaneously excite fluorescence and substantially simultaneously monitor separations in multiple capillaries. This multiplexing approach involves laser irradiation of a sample in a plurality of capillaries through optical fibers that are coupled individually with the capillaries. The array is imaged orthogonally through a microscope onto a charge-coupled device camera for signal analysis.

Yeung, Edward S. (Ames, IA); Taylor, John A. (Nevada, IA)

1996-03-12

275

Malpighi and the Discovery of Capillaries  

Microsoft Academic Search

Leonardo da Vinci clearly observed and described capillaries. Using the microscope, Marcello Malpighi examined the brain and major organs to demonstrate their finer anatomical features. This led to his discovery in 1661, of capillaries that proved fundamental to our understanding of the vascular system in the brain and cord. He hypothesized that capillaries were the connection between arteries and veins

J. M. S. Pearce

2007-01-01

276

Recent advances in pressurized capillary electrochromatography  

Microsoft Academic Search

Pressurized capillary electrochromatography (pCEC) is an analytical technique that has attracted increased interests in recent years. In pCEC, both pressure and electric field are applied to a capillary column to achieve separation of analytes. It combines various aspects of capillary electrochromatography (CEC) and liquid chromatography (LC). In this review, recent developments, both theoretical and experimental, were presented. The practical aspects

Xue Gu; Xiaojing Huang; Chao Yan

277

Capillary Rise in a Wedge  

ERIC Educational Resources Information Center

|In introductory-level physics courses, the concept of surface tension is often illustrated using the example of capillary rise in thin tubes. In this paper the author describes experiments conducted using a planar geometry created with two small plates forming a thin wedge. The distribution of the fluid entering the wedge can be studied as a…

Piva, M.

2009-01-01

278

Influence of wettability on interfacial area during immiscible liquid invasion into a 3D self-affine rough fracture: Lattice Boltzmann simulations  

NASA Astrophysics Data System (ADS)

In this work, the influence of wettability on the fluid–fluid interfacial area (anw) in a three-dimensional (3D) self-affine rough fracture during non-wetting phase invasion was studied using the lattice Boltzmann method (LBM). The capillary pressure (Pc)-saturation (Sw)-interfacial area (Pc–Sw–anw) relationship, irreducible water saturation, and anw at non-wetting phase breakthrough time and at irreducible water saturation were determined for four different contact angles. The lower contact angles led to increases in both Pc and anw for a given water saturation. The irreducible water saturation increased as contact angle decreased and the corresponding anw at irreducible saturation also increased as contact angle decreased. Decreasing the contact angle with the corresponding increase in non-wetting phase entry pressures increased the number of fracture regions in which water became surrounded by NAPL and isolated. This consequently increased anw for a given water saturation and increased the irreducible water saturation. The anw–Sw curves from LBM for different contact angles were compared with a thermodynamically based model for the anw–Sw relationship. The energy dissipation factors varied with contact angle, and were higher than typical values for porous media, indicating predictions of less energy dissipation in the fractures modeled than for previously studied porous media.

Dou, Zhi; Zhou, Zhifang; Sleep, B. E.

2013-11-01

279

DNA Sequencing Using capillary Electrophoresis  

SciTech Connect

The overall goal of this program was to develop capillary electrophoresis as the tool to be used to sequence for the first time the Human Genome. Our program was part of the Human Genome Project. In this work, we were highly successful and the replaceable polymer we developed, linear polyacrylamide, was used by the DOE sequencing lab in California to sequence a significant portion of the human genome using the MegaBase multiple capillary array electrophoresis instrument. In this final report, we summarize our efforts and success. We began our work by separating by capillary electrophoresis double strand oligonucleotides using cross-linked polyacrylamide gels in fused silica capillaries. This work showed the potential of the methodology. However, preparation of such cross-linked gel capillaries was difficult with poor reproducibility, and even more important, the columns were not very stable. We improved stability by using non-cross linked linear polyacrylamide. Here, the entangled linear chains could move when osmotic pressure (e.g. sample injection) was imposed on the polymer matrix. This relaxation of the polymer dissipated the stress in the column. Our next advance was to use significantly lower concentrations of the linear polyacrylamide that the polymer could be automatically blown out after each run and replaced with fresh linear polymer solution. In this way, a new column was available for each analytical run. Finally, while testing many linear polymers, we selected linear polyacrylamide as the best matrix as it was the most hydrophilic polymer available. Under our DOE program, we demonstrated initially the success of the linear polyacrylamide to separate double strand DNA. We note that the method is used even today to assay purity of double stranded DNA fragments. Our focus, of course, was on the separation of single stranded DNA for sequencing purposes. In one paper, we demonstrated the success of our approach in sequencing up to 500 bases. Other application papers of sequencing up to this level were also published in the mid 1990's. A major interest of the sequencing community has always been read length. The longer the sequence read per run the more efficient the process as well as the ability to read repeat sequences. We therefore devoted a great deal of time to studying the factors influencing read length in capillary electrophoresis, including polymer type and molecule weight, capillary column temperature, applied electric field, etc. In our initial optimization, we were able to demonstrate, for the first time, the sequencing of over 1000 bases with 90% accuracy. The run required 80 minutes for separation. Sequencing of 1000 bases per column was next demonstrated on a multiple capillary instrument. Our studies revealed that linear polyacrylamide produced the longest read lengths because the hydrophilic single strand DNA had minimal interaction with the very hydrophilic linear polyacrylamide. Any interaction of the DNA with the polymer would lead to broader peaks and lower read length. Another important parameter was the molecular weight of the linear chains. High molecular weight (> 1 MDA) was important to allow the long single strand DNA to reptate through the entangled polymer matrix. In an important paper, we showed an inverse emulsion method to prepare reproducibility linear polyacrylamide polymer with an average MWT of 9MDa. This approach was used in the polymer for sequencing the human genome. Another critical factor in the successful use of capillary electrophoresis for sequencing was the sample preparation method. In the Sanger sequencing reaction, high concentration of salts and dideoxynucleotide remained. Since the sample was introduced to the capillary column by electrokinetic injection, these salt ions would be favorably injected into the column over the sequencing fragments, thus reducing the signal for longer fragments and hence reading read length. In two papers, we examined the role of individual components from the sequencing reaction and then developed a protocol to reduce the deleterio

Dr. Barry Karger

2011-05-09

280

Gradient elution in capillary electrochromatography  

SciTech Connect

In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically-driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with sub-mL/min flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-mm reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled programmable high-voltage power supplies (0-50 kV)--one providing an increasing ramp and the other providing a decreasing ramp--are used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically-driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons (PAHs) was separated in less than 90 minutes. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC, but also other types of gradients such as pH- and ionic-strength gradients in capillary electrokinetic separations and analyses.

Anex, D.; Rakestraw, D.J. [Sandia National Labs., Livermore, CA (United States); Yan, Chao; Dadoo, R.; Zare, R.N. [Stanford Univ., CA (United States). Dept. of Chemistry

1997-08-01

281

Gradient elution in capillary electrochromatography.  

PubMed

In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with submicroliter per minute flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-?m reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase, and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled, programmable, high-voltage power supplies (0-50 kV) [Formula: see text] one providing an increasing ramp and the other providing a decreasing ramp [Formula: see text] are used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons was separated in less than 90 min. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC but also other types of gradients, such as pH and ionic strength gradients, in capillary electrokinetic separations and analyses. PMID:21619344

Yan, C; Dadoo, R; Zare, R N; Rakestraw, D J; Anex, D S

1996-09-01

282

Capillary forces between sediment particles and an air-water interface.  

PubMed

In the vadose zone, air-water interfaces play an important role in particle fate and transport, as particles can attach to the air-water interfaces by action of capillary forces. This attachment can either retard or enhance the movement of particles, depending on whether the air-water interfaces are stationary or mobile. Here we use three standard PTFE particles (sphere, circular cylinder, and tent) and seven natural mineral particles (basalt, granite, hematite, magnetite, mica, milky quartz, and clear quartz) to quantify the capillary forces between an air-water interface and the different particles. Capillary forces were determined experimentally using tensiometry, and theoretically assuming volume-equivalent spherical, ellipsoidal, and circular cylinder shapes. We experimentally distinguished between the maximum capillary force and the snap-off force when the air-water interface detaches from the particle. Theoretical and experimental values of capillary forces were of similar order of magnitude. The sphere gave the smallest theoretical capillary force, and the circular cylinder had the largest force due to pinning of the air-water interface. Pinning was less pronounced for natural particles when compared to the circular cylinder. Ellipsoids gave the best agreement with measured forces, suggesting that this shape can provide a reasonable estimation of capillary forces for many natural particles. PMID:22423648

Chatterjee, Nirmalya; Lapin, Sergey; Flury, Markus

2012-04-04

283

Enhancing the settlement and attachment strength of pediveligers of Mytilus galloprovincialis by changing surface wettability and microtopography.  

PubMed

Surface wettability and microtopography can either enhance or deter larval settlement of many sessile marine organisms. This study quantifies the effect of these surface properties on the settlement of pediveligers of Mytilus galloprovincialis, using polymers spanning a range of wettability and microtextured polydimethylsiloxane (PDMS). Furthermore, the adhesion strength of settled pediveligers on microtextured PDMS surfaces was quantified using a flow chamber. Settlement was enhanced at the hydrophilic end of the wettability spectrum, where mean settlement on nylon reached 33.5 ± 13.1%. In contrast, mean settlement on the most hydrophobic polymer (PDMS) was 4.2 ± 3.2%. Microtopography had a much stronger effect compared to wettability, where 400 ?m textured PDMS enhanced settlement above 90%. Settlement preferences were also positively correlated to adhesion strength at flow rates of 4 knots, with all initially settled pediveligers on smooth PDMS detaching, while 79.9 ± 5.7% of pediveligers remained on the 400 ?m texture. PMID:22332795

Carl, C; Poole, A J; Sexton, B A; Glenn, F L; Vucko, M J; Williams, M R; Whalan, S; de Nys, R

2012-01-01

284

Wettability and corrosion of TiN, TiN–BN and TiN-AlN by liquid steel  

Microsoft Academic Search

The wettability and corrosion behaviour of titanium nitride by liquid steel has been studied. Due to its thermodynamic stability and low solubility in liquid iron, TiN has a good resistance to corrosion by liquid steel. However, its good wettability promotes adhesion to steel. Also, the effects of BN and AlN addition to TiN on the wetting parameters and the mechanisms

A Amadeh; S Heshmati-Manesh; J. C Labbe; A Laimeche; P Quintard

2001-01-01

285

Surface roughness and wettability of AISI 316L induced by surface mechanical attrition treatment with different milling ball diameter  

Microsoft Academic Search

Surface roughness and wettability determines the rate and quality of protein adsorption and cells adhesion on biomaterial. For this case, a rough- and hydrophilic-surface are preferable rather than a smooth- and hydrophobic-one. This paper discusses the effect of milling ball diameter used in surface mechanical attrition treatment (SMAT) on the roughness and wettability of AISI 316L. All samples were treated

B. Arifvianto; Suyitno

2009-01-01

286

Micro-nano hybrid structures with manipulated wettability using a two-step silicon etching on a large area  

Microsoft Academic Search

Nanoscale surface manipulation technique to control the surface roughness and the wettability is a challenging field for performance\\u000a enhancement in boiling heat transfer. In this study, micro-nano hybrid structures (MNHS) with hierarchical geometries that\\u000a lead to maximizing of surface area, roughness, and wettability are developed for the boiling applications. MNHS structures\\u000a consist of micropillars or microcavities along with nanowires having

Beom Seok Kim; Sangwoo Shin; Seung Jae Shin; Kyung Min Kim; Hyung Hee Cho

2011-01-01

287

Experimental displacement patterns in a 2 × 2 quadrant block with permeability and wettability heterogeneities—problems for numerical modelling  

Microsoft Academic Search

The effect of heterogeneities on miscible and immiscible flood displacements in 2D bead packs in quadrant form, 2 × 2 block\\u000a heterogeneity, with either a permeability or a wettability contrast is the subject of this paper. The physical processes occurring\\u000a during miscible and immiscible flow and displacement within permeability and wettability quadrant bead pack models have been\\u000a studied experimentally. This geometry

Richard A. Dawe; Carlos A. Grattoni

2008-01-01

288

Breakup of drops and bubbles translating through cylindrical capillaries  

NASA Astrophysics Data System (ADS)

We examine the shape deformation and breakup of air bubbles and viscous drops moving through vertical cylindrical capillaries under the action of pressure and/or buoyancy forces. Experimental observations of fluid particle shape are reported over a wide range of particle sizes and capillary numbers in a variety of two-phase systems. Four different modes of breakup are identified, and the critical conditions for the onset of various modes are examined. It is found that buoyancy forces can have a stabilizing effect on the breakup mechanism observed by Olbricht and Kung [Phys. Fluids 4, 134, (1992)] for low viscosity-ratio drops, wherein a growing indentation at the trailing end of the drop develops into a penetrating jet of outer phase fluid.

Borhan, A.; Pallinti, J.

1999-10-01

289

Effects of aqueous polymeric surfactants on silicone-hydrogel soft- contact-lens wettability and bacterial adhesion of Pseudomonas aeruginosa.  

PubMed

Prevention of Pseudomonas aeruginosa binding to soft-contact lenses (SCLs) may curtail sight-threatening microbial keratitis. Substrate surface wettability is known to modulate adhesion of P. aeruginosa. This study investigates the use of aqueous alkoxylate block co-polymer surfactants for enhanced wettability and antibacterial adhesion of SCLs under leaching conditions. Specifically, Pluronic(®) F127 (PF) and three ethylene oxide-butylene oxide (EOBO) surfactants were studied with four commercially available silicone-hydrogel contact lenses: Pure Vision™, Acuvue Advance™, Acuvue Oasys™ and O(2)Optix™. Dilute aqueous PF and EOBO surfactants impregnated all four soft-contact lenses, as demonstrated by surface-tension decline for leached surfactant. For PF surfactant, significant surface-wettability improvement upon rinsing occurred only after overnight leaching. EOBO surfactant showed a similar pattern with O(2)Optix™ lenses. EOBO-pretreated Pure Vision™ lenses, however, showed fast leaching and a significant change in surface energy towards improved wettability. Adhesion assays of P. aeruginosa displayed a small decrease in the binding rate of PAK bacteria for EOBO-pretreated Pure Vision™ lenses, but not for EOBO-pretreated O(2)Optix™ lenses. P. aeruginosa strain-PAO1 bacteria adhesion to all lenses was independent of surface wettability. Despite the ability of polymeric surfactants to lower advancing contact angles under leaching conditions, increased lens wettability is not a universal panacea for antifouling of soft-contact lenses. PMID:22456099

Tran, Victoria B; Sung, Ye Suel; Copley, Kendra; Radke, C J

2012-03-26

290

A superhydrophobic to superhydrophilic in situ wettability switch of microstructured polypyrrole surfaces.  

PubMed

We present an electrochemical layered system that allows for the fast, in situ wettability switch of microstructured PPy upon the application of an electric stimulus. We have eliminated the need for PPy to be immersed in an electrolyte to switch between wetting states, laying the groundwork for PPy to be used as a viable material in many applications, including microfluidics or smart textiles. The PPy surface was switched from the superhydrophobic state (contact angle=159) to the superhydrophilic state (contact angle=0) in 3 s. A wettability gradient was also created on a PPy surface using the layered system, causing a 3 µL droplet to travel approximately 2 mm in 0.8 s. PMID:21544891

Chang, Jean H; Hunter, Ian W

2011-03-11

291

Dynamical surface affinity of diphasic liquids as a probe of wettability of multimodal porous media.  

PubMed

We introduce a method for estimating the wettability of rock/oil/brine systems using noninvasive in situ nuclear magnetic relaxation dispersion. This technique scans over a large range of applied magnetic fields and yields unique information about the extent to which a fluid is dynamically correlated with a solid rock surface. Unlike conventional transverse relaxation studies, this approach is a direct probe of the dynamical surface affinity of fluids. To quantify these features we introduce a microscopic dynamical surface affinity index which measures the dynamical correlation (i.e., the microscopic wettability) between the diffusive fluid and the fixed paramagnetic relaxation sources at the pore surfaces. We apply this method to carbonate reservoir rocks which are known to hold about two thirds of the world's oil reserves. Although this nondestructive method concerns here an application to rocks, it could be generalized as an in situ liquid/surface affinity indicator for any multimodal porous medium including porous biological media. PMID:20365175

Korb, J-P; Freiman, G; Nicot, B; Ligneul, P

2009-12-01

292

Enhanced wettability of a SU-8 photoresist through a photografting procedure for bioanalytical device applications  

NASA Astrophysics Data System (ADS)

In this work, we detail a method whereby a polymeric hydrogel layer is grafted to negative tone photoresist SU-8 in order to improve its wettability. A photoinitiator is first immobilized on freshly prepared SU-8 samples, acting as the starting point for various surface modification strategies. Grafting of a 2-hydroxyethylmethacrylate-based hydrogel from the SU-8 surface resulted in the reduction of the static contact angle of a water droplet from 79 ± 1° to 36 ± 1°, while addition of a poly(ethylene glycol)-rich hydrogel layer resulted in further improvement (8 ± 1°). Wettability is greatly enhanced after 30 min of polymerization, with a continued but more gradual decrease in contact angle up to approximately 50 min. Hydrogel formation is triggered by exposure to UV irradiation, allowing for the formation of photopatterned structures using existing photolithographic techniques.

Gao, Zhan; Henthorn, David B.; Kim, Chang-Soo

2008-04-01

293

Wettability and spreading: Two key parameters in oil recovery with three-phase gravity drainage  

SciTech Connect

The objective of this paper is to show that the porous medium wettability and the spreading characteristics of the fluid system hold the key roles in three-phase gas injection, and to study to which extent these two parameters affect oil recovery and phase distributions. To this end gravity assisted inert gas injection experiments have been performed in water-wet, oil-wet and fractionally-wet porous media for spreading and nonspreading conditions. The experiments are simulated and the oil and gas relative permeabilities for three-phase flow are calculated by history matching. It is proved that the existence of wetting and spreading oil films--caused by wettability and spreading--greatly affects the flow mechanisms and consequently the recovery kinetics and the process efficiency. The results are interpreted in terms of physicochemical parameters on the basis of pore scale mechanisms.

Vizika, O.; Lombard, J.M. [Inst. Francais du Petrole, Rueil-Malmaison (France)

1996-02-01

294

Determination of metalaxyl and identification of adjuvants in wettable powder pesticide technical formulas  

Microsoft Academic Search

Foliar runoff is one of the most important processes affecting off-target movement of fungicides. In this way, Ridomil® Gold\\u000a Plus and Ridomil® Gold MZ are two types of wettable powder technical formulations which contain metalaxyl and they are used\\u000a for such a purpose. A method for quantitative determination of metalaxyl in pesticide formulas has been developed, validated,\\u000a and subsequently applied

Eva Pose-Juan; Raquel Rial-Otero; Elena Martínez-Carballo; Eugenio López-Periago; Jesús Simal-Gándara

2009-01-01

295

Investigation of interactions of diluted microemulsions with shale rock and sand by adsorption and wettability measurements  

Microsoft Academic Search

Water-in-oil, oil-in-water and balanced microemulsions made with ethoxylated alcohol surfactant and d-limonene as the oil phase were diluted with distilled water and 2% KCl solutions. The interactions between these diluted microemulsions and Marcellus shale rock were studied by performing adsorption and wettability measurements. Interaction of the balanced microemulsion solutions with sand was studied by monitoring change in the surface tension

Andrei S. Zelenev; Lakia M. Champagne; Michael Hamilton

296

Wettability and the Capture, Carriage and Deposition of Particles by Raindrops  

Microsoft Academic Search

DURING rain the particulate matter of the atmosphere is washed to the ground, and it has been suggested that the wettability of the particles affects the efficiency with which they are picked up by the falling droplets. The rain-wash of fungal spores which are not easily wetted has been reported, however, by Gregory1and Hirst2. It was therefore decided to investigate

R. R. Davies

1961-01-01

297

Cell adhesion and cytotoxicity studies over polyanionic collagen surfaces with variable negative charge and wettability  

Microsoft Academic Search

This work describes the cytotoxicity, and the cell adhesion behavior of K562 cell line from human erythroleukemia transfected with the DNA for the ?2?1 integrin over type-I collagen matrices with variable degree of carboxyl group and wettability. The results showed that type-I collagen materials with variable degree of carboxyl group prepared by selective hydrolysis of carboxyamide side chains of Asn

M. R Bet; G Goissis; S Vargas; H. S Selistre-de-Araujo

2003-01-01

298

Wettable arrays onto superhydrophobic surfaces for bioactivity testing of inorganic nanoparticles  

Microsoft Academic Search

Poly(l-lactic acid) superhydrophobic surfaces prepared by a phase-separation methodology were treated with 30min exposition of UV\\/O3 irradiation using hollowed masks in order to obtain patterned superhydrophilic squared-shaped areas. These wettable areas successfully confined bioactive glass nanoparticles (BG-NPs), by dispensing and drying individual droplets of BG-NPs suspensions. The obtained biomimetic chips were used to test the in vitro bioactivity of binary

Gisela M. Luz; Álvaro J. Leite; Ana I. Neto; Wenlong Song; João F. Mano

2011-01-01

299

How is wettability of titanium surfaces influenced by their preparation and storage conditions?  

Microsoft Academic Search

The effect of two different etching procedures with inorganic acids (HSE and CSE)—one using additionally strongly oxidising\\u000a conditions due to the presence of CrO3 (CSE)—and consecutive storage conditions (dry methanol and air) for previous corundum blasted titanium surfaces is compared\\u000a with respect to their wettability behaviour and the potential of the etching processes for removing remaining blasting material.\\u000a The etching

D. Scharnweber; F. Schlottig; S. Oswald; K. Becker; H. Worch

2010-01-01

300

The role of surface wettability on hepatocyte adhesive interactions and function  

Microsoft Academic Search

In this paper the effect of surface wettability on hepatocyte morphology and function was studied, using clean and octadecylsylane (ODS)-coated glass as a model for hydrophilic and hydrophobic surfaces, respectively. C3A cells - a hepatoblastoma cell line, and freshly obtained porcine hepatocytes were cultured for a short-time period of up to 4 days on the above substrata. Hepatocyte adhesive interactions

N. Krasteva; Th. Groth; F. Fey-Lamprecht; G. Altankov

2001-01-01

301

Insights into the role of material surface topography and wettability on cell-material interactions  

Microsoft Academic Search

This work investigates the effect of surface topography and biomaterial wettability on protein absorption, cell attachment, proliferation and morphology and reveals important insights in the complexity of cell-material interactions. We use various materials, i.e. poly(dimethyl siloxane) (PDMS), poly(L-lactic acid) (PLLA), a co-polymer of poly(ethylene oxide) and poly(butylene terephtalate) (PEOT\\/PBT) and tissue culture polystyrene (TCPS) as a reference. These materials are

Bernke J. Papenburg; Emillie Dooms Rodrigues; Matthias Wessling; Dimitrios Stamatialis

2010-01-01

302

Wettability and rate effects on immiscible displacement: Lattice Boltzmann simulation in microtomographic images of reservoir rocks  

Microsoft Academic Search

Pore networks derived from synchrotron X-ray microtomographic images of reservoir rocks were used to provide realistic geometries for simulation of oil displacement by water. The Lattice Boltzmann Method was used to compute two-phase flow dynamics with constant pore geometry—but different pressure driving forces and imposed wettability distributions at the pore wall boundaries. Such examinations can be used to formulate more

R. D. Hazlett; S. Y. Chen; W. E. Soll

1998-01-01

303

High-temperature wettability of aluminum nitride during liquid metal infiltration  

Microsoft Academic Search

The high-temperature wettability of AlN particle preforms with pure molten Cu, Al and Pb is quantified by means of drainage curves measured during pressure infiltration. By integrating the drainage curves obtained in this study, the work of immersion for each system can be estimated, allowing in turn to deduce an apparent contact angle for wetting of AlN by these metals.

M. Kida; M. Bahraini; J. M. Molina; L. Weber; A. Mortensen

2008-01-01

304

Surface roughness, porosity and wettability of gentamicin-loaded bone cements and their antibiotic release  

Microsoft Academic Search

In this study, the release of gentamicin as a function of time was measured for six different gentamicin-loaded bone cements and related with the surface roughness, porosity and wettability of the cements. Initial release rates varied little between the six bone cements (CMW1, CMW3, CMW Endurance, CMW 2000, Palacos, and Palamed) and ranged from 8.6 to 14.1?g\\/cm2\\/h. The total amounts

H van de Belt; D Neut; D. R. A Uges; W Schenk; J. R van Horn; H. C van der Mei; H. J Busscher

2000-01-01

305

Effect of Microstructural Evolution on Wettability of Laser Coated Calcium Phosphate on Titanium Alloy  

SciTech Connect

Surface engineering of synthetic implant materials provides an exciting opportunity to mimic natural biomaterials. Surface that are bioactive and textured at multi scale have the potential for easier osseointegration. Ti alloy surfaces known for their biocompatibility are coated with bioactive Calcium Phosphate using a laser source at multiple processing speeds. The resulting surface has multiscale morphology and multi-phase chemical nature. Faster processing speeds showed improved wettability to water along with higher degree of crystallinity in the phases present.

Kurella, Anil K [ORNL; Hu, Michael Z. [ORNL; Dahotre, Narendra B [ORNL

2008-01-01

306

Effect of drying method on the surface wettability of wood strands  

Microsoft Academic Search

An experiment was conducted to investigate the effects of drying methods, namely rotary drum, lab\\u000a oven, microwave and air-drying, on the surface wettability of wood strands by the Wilhelmy plate method.\\u000a The measurements included the surface contact angle, free energy, and liquid sorption capacity. Thirty\\u000a industrial strands including southern yellow pine (Pinus spp.) and poplar\\u000a (Populus spp.) were randomly collected

Siqun Wang; Yang Zhang; Cheng Xing

2007-01-01

307

WETTABILITY AND PREDICTION OF OIL RECOVERY FROM RESERVOIRS DEVELOPED WITH MODERN DRILLING AND COMPLETION FLUIDS  

SciTech Connect

Exposure to crude oil in the presence of an initial brine saturation can render rocks mixed-wet. Subsequent exposure to components of synthetic oil-based drilling fluids can alter the wetting toward less water-wet or more oil-wet conditions. Mixing of the non-aromatic base oils used in synthetic oil-based muds (SBM) with an asphaltic crude oil can destabilize asphaltenes and make cores less water-wet. Wetting changes can also occur due to contact with the surfactants used in SBM formulations to emulsify water and make the rock cuttings oil-wet. Reservoir cores drilled with SBMs, therefore, show wetting properties much different from the reservoir wetting conditions, invalidating laboratory core analysis using SBM contaminated cores. Core cleaning is required in order to remove all the drilling mud contaminants. In theory, core wettability can then be restored to reservoir wetting conditions by exposure to brine and crude oil. The efficiency of core cleaning of SBM contaminated cores has been explored in this study. A new core cleaning procedure was developed aimed to remove the adsorbed asphaltenes and emulsifiers from the contaminated Berea sandstone cores. Sodium hydroxide was introduced into the cleaning process in order to create a strongly alkaline condition. The high pH environment in the pore spaces changed the electrical charges of both basic and acidic functional groups, reducing the attractive interactions between adsorbing materials and the rock surface. In cores, flow-through and extraction methods were investigated. The effectiveness of the cleaning procedure was assessed by spontaneous imbibition tests and Amott wettability measurements. Test results indicating that introduction of sodium hydroxide played a key role in removing adsorbed materials were confirmed by contact angle measurements on similarly treated mica surfaces. Cleaning of the contaminated cores reversed their wettability from oil-wet to strongly water-wet as demonstrated by spontaneous imbibition rates and Amott wettability indices.

Jill S. Buckley; Norman R. Morrow

2005-04-01

308

Foliar Nitrogen Uptake from Wet Deposition and the Relation with Leaf Wettability and Water Storage Capacity  

Microsoft Academic Search

This study assessed the foliar uptake of 15N-labelled nitrogen (N) originating from wet deposition along with leaf surface conditions, measured by wettability and water\\u000a storage capacity. Foliar 15N uptake was measured on saplings of silver birch, European beech, pedunculate oak and Scots pine and the effect of nitrogen\\u000a form (NH4+ or NO3?), NH4+ to NO3? ratio and leaf phenology on

Sandy Adriaenssens; Jeroen Staelens; Karen Wuyts; An de Schrijver; Shari Van Wittenberghe; Tatiana Wuytack; Fatemeh Kardel; Kris Verheyen; Roeland Samson; Pascal Boeckx

2011-01-01

309

Measurement and modeling of hydraulic characteristics of unsaturated porous media with mixed wettability  

Microsoft Academic Search

The spatial distribution of the solid grain's wettability strongly influences the phase-interconnection, phase-flow and solute transport in unsaturated porous media. Non-uniform wetting conditions can arise in soils and aquifers from natural or anthropogenic impacts. In this study, a water–air system in porous media consisting of several types of granular materials is considered. A conceptual model for pressure-wise estimation of water

Petr Ustohal; Fritz Stauffer; Themistocles Dracos

1998-01-01

310

A strategy of fast reversible wettability changes of WO 3 surfaces between superhydrophilicity and superhydrophobicity  

Microsoft Academic Search

As-prepared WO3 nanostructure films on alumina or tungsten substrates by a facile hydrothermal method exhibit a superhydrophilic property. An effective strategy is proposed to control the wettability of WO3 films in a reversible manner between superhydrophilicity and superhydrophobicity with a rapid response. By controlling the process of adsorption\\/desorption of n-dodecanethiol associated with the light-induced plating Ag nano-grains on WO3 nanostructures,

Changdong Gu; Jun Zhang; Jiangping Tu

2010-01-01

311

Wettability of quartz in presence of nonionic surfactants and short chain alcohols mixtures  

Microsoft Academic Search

Measurements of advancing contact angles for aqueous solution of Triton X-100 (TX-100) with methanol, ethanol and propanol mixtures and Triton X-165 (TX-165) with the same alcohols on quartz surface were carried out. From the obtained results it appeared that the wettability of quartz depends on Triton’s and alcohol concentrations and that there is a linear dependence between the adhesional and

Anna Zdziennicka; Bronis?aw Ja?czuk

2010-01-01

312

The economics of inert anodes and wettable cathodes for aluminum reduction cells  

Microsoft Academic Search

Estimating the impact of inert-anode and wettable-cathode technologies on smelter costs must be speculative because no such\\u000a technologies have yet been commercialized. Even so, some broad conclusions can be drawn about the economic merit of inert\\u000a anodes in retrofit and greenfield smelter scenarios. Study suggests that retrofitting inert anodes to existing prebake cells\\u000a generates insufficient economic benefit to justify this

Jeff Keniry

2001-01-01

313

Effects of wettability and pore-level displacement on hydrocarbon trapping  

NASA Astrophysics Data System (ADS)

We use a three-dimensional mixed-wet random network model representing Berea sandstone to extend our previous work on relative permeability hysteresis during water-alternating-gas (WAG) injection cycles [Suicmez, VS, Piri, M, Blunt, MJ, 2007, Pore-scale simulation of water alternate gas injection, Transport Porous Med 66(3), 259-86]. We compute the trapped hydrocarbon saturation for tertiary water-flooding, which is water injection into different initial gas saturations, Sgi, established by secondary gas injection after primary drainage. Tertiary water-flooding is continued until all the gas and oil is trapped. We study four different wettability conditions: water-wet, weakly water-wet, weakly oil-wet and oil-wet. We demonstrate that the amounts of oil and gas that are trapped show surprising trends with wettability that cannot be captured using previously developed empirical trapping models. We show that the amount of oil that is trapped by water in the presence of gas increases as the medium becomes more oil-wet, which is opposite from that seen for two-phase flow. It is only through a careful analysis of displacement statistics and fluid configurations that these results can be explained. This illustrates the need to have detailed models of the displacement processes that represent the three-phase displacement physics as carefully as possible. Further work is needed to explore the full range of behavior as a function of wettability and displacement path.

Suicmez, V. Sander; Piri, Mohammad; Blunt, Martin J.

2008-03-01

314

Mussel (Mytilus edulis) byssus deposition in response to variations in surface wettability  

PubMed Central

Mussels (Mytilus edulis) are economically important in their role as an aquaculture species and also with regard to marine biofouling. They attach tenaciously to a wide variety of submerged surfaces by virtue of collagenous attachment threads termed ‘byssi’. The aim of this study was to characterize the spreading of the byssal attachment plaque, which mediates attachment to the surface, on a range of surfaces in response to changes in wettability. To achieve this, well characterized self-assembled monolayers of ?-terminated alkanethiolates on gold were used, allowing correlation of byssal plaque spreading with a single surface characteristic—wettability. The present results were inconsistent with those from previous studies, in that there was a positive correlation between plaque size and surface wettability; a trend which is not explained by conventional wetting theory for a three-phase system. A recent extension to wetting theory with regard to hydrophilic proteins is discussed and the results of settlement assays are used to attempt reconciliation of these results with those of similar previous studies and, also, with recent data presented for the spreading of Ulva linza spore adhesive.

Aldred, N; Ista, L.K; Callow, M.E; Callow, J.A; Lopez, G.P; Clare, A.S

2005-01-01

315

Rapidly switched wettability of titania films deposited by dc magnetron sputtering  

NASA Astrophysics Data System (ADS)

Rapid switching (5-15 minutes) in the wettability of titania (TiO2) thin films in the anatase phase has been observed after UV irradiation. The film surface becomes superhydrophilic when exposed to UV radiation. The relationship between wettability, thickness and crystallinity of TiO2 films has been investigated. Amorphous and anatase TiO2 thin films have been deposited by varying the argon to oxygen gas ratio, using the reactive dc magnetron sputtering technique. It was found that the gas ratio primarily affects thickness, crystallinity, morphology and wettability of the films. The highest contact angle that has been reported so far, namely, 170°-176°, has been observed for film thickness varying from 112-500 nm in the case of pristine anatase TiO2 films. On the other hand, amorphous films show a variation in the contact angle from 120° to 140° as the thickness varied from 70 to 145 nm. The deposition is extremely robust and has an ultralow hysteresis in the contact angle. The films exhibit a morphology similar to the lotus leaf and the water hyacinth.

Shirolkar, Mandar; Kazemian Abyaneh, Majid; Singh, Akanksha; Tomer, Anju; Choudhary, Ram; Sathe, Vasant; Phase, Deodatta; Kulkarni, Sulabha

2008-08-01

316

Wettability of brazing alloys on molybdenum and TZM (Mo-Ti-Zr alloy)  

SciTech Connect

Vacuum brazing studies have been performed on molybdenum and TZM (0.5Ti-0.08Zr-Mo). Wettability tests have been conducted for nineteen braze metal filler alloys on molybdenum and thirty-two braze metal filler alloys on TZM over a wide range of temperatures. A wetting index, which is a function of contact angle and braze alloy contact area, was determined for each filler alloy at each brazing temperature. The nature and extent of interaction between the brazing alloys and the base metals was analyzed by conventional metallography, scanning-electron microscopy, and electron microprobe analysis. A comparison is made between the behavior of filler alloys on molybdenum and TZM -- filler alloys consistently exhibited less wettability on TZM than on molybdenum. The lower wettability of TZM is believed to be due to a small amount of titanium in the surface oxide on TZM. Cracking was observed in the base metal under some of the high temperature braze deposits. The cracking is shown to arise from liquid metal embrittlement from nickel in the high temperature braze alloys. 7 refs., 11 figs., 2 tabs.

McDonald, M.M.; Keller, D.L.; Heiple, C.R.; Hofmann, W.E.

1988-01-01

317

Mixed Capillary Venous Retroperitoneal Hemangioma  

PubMed Central

We report a case of mixed capillary venous hemangioma of the retroperitoneum in a 61-year-old man. Abdominal ultrasonography showed a mass to be hypoechoic with increased flow in color Doppler imaging. Dynamic contrast-enhanced computed tomography revealed a centripetal filling-in of the mass, located anterior to the left psoas muscle at the level of sacroiliac joint. On the basis of imaging features, preoperative diagnosis of hemangioma was considered and the mass was excised by laparoscopic method. Immunohistochemical studies were strongly positive for CD31 and CD34, and negative for calretinin, EMA, WT1, HMB45, Ki67, synaptophysin, and lymphatic endothelial cell marker D2–40. Histologically, the neoplasm was diagnosed as mixed capillary venous hemangioma.

Godar, Mohit; Yuan, Qinghai; Shakya, Rukeshman; Xia, Yang

2013-01-01

318

A rectangular capillary suction apparatus  

SciTech Connect

Fluid flow and cake formation in a rectangular capillary suction apparatus (RCSA) are investigated experimentally and theoretically. Water, methanol, ethanol, and ethylene glycol are used to study the effects of liquid properties, and CaCO[sub 3], kaolin, and bentonite slurries are employed for studying the effects of cake formation on capillary suction-time (CST). A theory based on a diffusion-like approach is developed. The liquid saturation under the inner cell will approach a constant value when the wet front distance is large. A method based on this experimental finding for estimating the cake specific resistance is proposed. The agreement between experiments and calculations is close. The RCSA is superior to the cylindrical CSA when treating liquids with small diffusivities or slurries with high solid concentration and/or with high averaged specific resistance.

Lee, D.J. (National Taiwan Univ., Taipei (Taiwan, Province of China). Dept. of Chemical Engineering); Hsu, Y.H. (Yuan-Ze Inst. of Tech., Taoyuan (Taiwan, Province of China). Dept. of Chemical Engineering)

1994-06-01

319

Capillary rise in cellulose sponges  

NASA Astrophysics Data System (ADS)

A cellulose sponge, commonly used for clean-up jobs, can absorb and hold a significant amount of water within its pores, whose size ranges from micrometers to millimeters. We investigate the dynamics of capillary rise of water in the sponge using a combination of experiment and theory. We find that the rate of the capillary rise is significantly lower than Washburn's rule that assumes the sponge as a row of adjoined pores and the liquid flow to be driven by the Laplace pressure. We introduce a novel theory to model the flow in the hygroscopic porous media by combining Darcy's law based on the moisture concentration and the modified Young-Laplace equation. The scaling law constructed through this work agrees well with the experimental results.

Kim, Jungchul; Kim, Ho-Young; Mahadevan, L.

2011-11-01

320

Elastic Recovery in Capillary Flow  

Microsoft Academic Search

IN a previous communication1 the non-Newtonian behaviour of certain visco-elastic materials, including rubber solutions and soap-thickened mineral oils, was discussed. Experiment had shown that when such liquids flow through a capillary there is a loss in pressure at the tube entrance followed by a uniform fall in pressure down the remainder of the tube. This loss was shown to be

A. C. Merrington

1945-01-01

321

Capillary Flow Limitations of Nanowicks  

NASA Astrophysics Data System (ADS)

Thermal management is an important issue in microelectronic systems. The inaccessibility and diminishing size of these systems, however, requires that the heat management components be reliable and compact, such as is the case with heat pipes. In most intermediate temperature heat pipes typically found in microelectronics, the critical heat flux is governed by the capillary limit. Given the projected increases in computer chip heat fluxes, it is important to investigate the use of nanowicks as a means of raising this capillary limit. A theoretical model was developed to simulate flow through a vertical nanopillar array by balancing the capillary driving forces and the viscous losses in a quasi-steady state dynamic formulation. Based on this model, the maximum mass flow and its critical heat flux can be found for a wick given its microstructure geometry. These values were also found experimentally for commercially available wicks and nanowicks. We found that nanowicks provide lower mass flow rates than conventional wicks, mainly due to a reduced cross section. However, nanowicks achieved higher velocities and show promise over some conventional heat pipe wicks.

Zhang, Conan; Hidrovo, Carlos

2009-11-01

322

Automated serum protein electrophoresis by Capillarys.  

PubMed

Capillary zone electrophoresis (CZE) of serum proteins is increasingly gaining impact in clinical laboratories. In this report, we evaluate automated capillary zone electrophoresis by Capillarys (Sebia, France). Within-run and between-run imprecision for the five electrophoretic fractions was <2% and <6%, respectively. Data obtained with Capillarys correlated with results obtained with agarose gel electrophoresis and Paragon CZE 2000 (Beckman Coulter, USA). Analysis of serum obtained from patients with inflammation, nephrotic syndrome, bisalbuminemia, and alpha1-antitrypsin deficiency revealed that Capillarys was able to detect these abnormalities. Two hundred thirty eight samples were analyzed by agarose gel electrophoresis, Capillarys, capillary electrophoresis using Paragon CZE 2000 system, and immunofixation. Sample selection was based on the presence of a disturbed morphology (e.g., spike) of the protein profile or hypogammaglobulinemia on agarose gel electrophoresis and/or Capillarys. Immunofixation revealed the presence of a monoclonal protein, oligoclonal bands, polyclonal pattern, and a normal profile in, respectively, 89, 66, 19, and 64 samples. With Capillarys, Paragon, and agarose gel electrophoresis, a spike and/or disturbed morphology of the profile was found in 222, 182, and 180 samples, respectively. In these samples, immunofixation was negative in 73 (33%), 46 (25%), and 39 (22%) samples, respectively. These data indicate that Capillarys has a lower specificity than agarose gel electrophoresis and Paragon 2000. Of the 89 samples with a monoclonal protein, Capillarys, Paragon, and agarose gel electrophoresis failed to detect, respectively, three, three, and one monoclonal protein(s). Interferences by radio-opaque agents, complement degradation products, fibrinogen, and triglycerides are described. In conclusion, automated capillary zone electrophoresis with Capillarys provides for reproducible, rapid, and reliable serum electrophoresis. PMID:12812271

Bossuyt, Xavier; Lissoir, Bénédicte; Mariën, Godelieve; Maisin, Diane; Vunckx, Jozef; Blanckaert, Norbert; Wallemacq, Pierre

2003-05-01

323

Joule heating in packed capillaries used in capillary electrochromatography.  

PubMed

Effective heat dissipation is critical for reproducible and efficient separations in electrically driven separation systems. Flow rate, retention kinetics, and analyte diffusion rates are some of the characteristics that are affected by variation in the temperature of the mobile phase inside the column. In this study, we examine the issue of Joule heating in packed capillary columns used in capillary electrochromatography (CEC). As almost all commonly used CEC packings are poor thermal conductors, it is assumed that the packing particles do not conduct heat and heat transfer is solely through the mobile phase flowing through the system. The electrical conductivity of various mobile phases was measured at different temperatures by a conductivity meter and the temperature coefficient for each mobile phase was calculated. This was followed by measurement of the electrical current at several applied voltages to calculate the conductivity of the solution within the column as a function of the applied voltage. An overall increase in the conductivity is attributed to Joule heating within the column, while a constant conductivity means good heat dissipation. A plot of conductivity versus applied voltage was used as the indicator of poor heat dissipation. Using theories that have been proposed earlier for modeling of Joule heating effects in capillary electrophoresis (CE), we estimated the temperature within CEC columns. Under mobile and stationary phase conditions typically used in CEC, heat dissipation was found to be not always efficient. Elevated temperatures within the columns in excess of 23 degrees C above ambient temperature were calculated for packed columns, and about 35 degrees C for an open column, under a given set of conditions. The results agree with recently published experimental findings with nuclear magnetic resonance (NMR) thermometry, and Raman spectroscopic measurements. PMID:12207300

Rathore, Anurag S; Reynolds, Kimberly J; Colón, Luis A

2002-09-01

324

Capillary Phenomena at Nanoscales: Electrowetting and Capillary Adhesion  

NASA Astrophysics Data System (ADS)

Theories of capillary phenomena have traditionally been based on continuum approximations that break down as dimensions shrink to nanometer scales. Molecular simulations are used to test the limits of continuum theory in electrowetting on dielectric (EWOD) and capillary adhesion between solids. In EWOD, a fluid drop is separated from an electrode by a dielectric. Increasing the voltage V between drop and electrode, decreases the contact angle ?, allowing the droplet to be manipulated. Simulations of nanoscale drops show the same behavior as experiments on millimeter drops. The contact angle follows the continuum Young-Lippmann equation (YLE) at low voltages and then saturates. The saturation mechanism has been difficult to identify in experiments. Simulations show that charged molecules are pulled from the drop by large electrostatic forces near the contact line. Saturation can be delayed by increasing molecular binding, lowering temperature or increasing dielectric constant. A local force balance equation is derived that agrees with the YLE below saturation and remains valid after saturation. Simulations of capillary adhesion examined the force between a spherical tip of radius R and a flat substrate. The shape of the meniscus agrees remarkably well with continuum theory down to nanometer separations, as does the adhesive force from interfacial tension. However, the total force may deviate by factors of two or have the opposite sign. While the component of the pressure along the substrate agrees with the Laplace pressure from continuum theory, the out-of --plane component does not. There may also be significant force oscillations associated with layering near the solids. The elastic response of the solid has little affect on adhesive forces.

Robbins, Mark

2011-11-01

325

Capillary concentrators for synchrotron radiation beamlines  

Microsoft Academic Search

Capillary concentrators condense x-rays by multiple reflections down a gradually tapering capillary. They can provide sub-micron beam spots, and are promising candidates for use in the next generation x-ray microprobe beamlines. The weak energy dependence of their properties make them especially useful for energy scanning applications such as micro-XAFS. This paper examines the potential performance of capillary optics for an

Steve M. Heald; Dale L. Brewe; Kyungha H. Kim; Frederick C. Brown; Bill Barg; Edward A. Stern

1996-01-01

326

"Seamless" endothelial cells of blood capillaries.  

PubMed

The distribution and number of seamless endothelial cells (SE) were studied in various organs and tissues of rats, rabbits and humans (1) by light microscopy after silver impregnation of the endothelial cell boundaries, (2) by electron microscopy, and (3) in three-dimensional reconstructions of duodenal villi and renal glomeruli. Since SE are situated mostly at branching points, the number of SE is roughly correlated to the number of branchings in the capillary system concerned. SE make up about 50% of all endothelial cells in the renal glomerulum and duodenal villi, and about 30% in the cerebral cortex. However, they rarely occur in bradytrophic tissues. SE have been found exclusively in net capillaries (true capillaries). They seem to be absent in most arterio-venous capillaries (capillary parts of thoroughfare channels), in the capillaries of endocrine glands, as well as in the sinusoidal systems of heart muscle, liver, spleen and bone marrow. It is concluded that SE are developed when tube formation is confined to a single endothelial cell. SE are intercalated most frequently in those capillaries that develop lastly in the terminal vascular bed. The seamless segments are canalized by fusion of intraendothelial vacuoles with pre-existing vascular walls. The existence of SE, confirming the dual structural design of capillary systems, may be used as a detector for net capillaries. PMID:6697387

Bär, T; Güldner, F H; Wolff, J R

1984-01-01

327

Capillaroscopy and the measurement of capillary pressure  

PubMed Central

Capillaries play a critical role in cardiovascular function as the point of exchange of nutrients and waste products between the tissues and circulation. Studies of capillary function in man are limited by access to the vascular bed. However, skin capillaries can readily be studied by the technique of capillaroscopy which enables the investigator to assess morphology, density and blood flow velocity. It is also possible to estimate capillary pressure by direct cannulation using glass micropipettes. This review will describe the techniques used to make these assessments and will outline some of the changes that are seen in health and disease.

Shore, Angela C

2000-01-01

328

Distribution of pulmonary capillary transit times.  

PubMed

The length of time that blood remains in the pulmonary capillary is an important variable in gas exchange. We have investigated the distribution of capillary transit times in isolated rabbit lungs perfused with a bicarbonate-free buffer. The time course of gas exchange was monitored by enclosing the lungs in a plethysmograph. A bolus of buffer containing dissolved acetylene was injected into the perfusion system. Exchange of this inert gas occurred as soon as the bolus reached the capillary bed, thereby describing the input function into the bed. A separate bolus injection of bicarbonate solution resulted in production and excretion of CO2 as long as the bolus remained in the capillary bed. The rate of CO2 production was adjusted by partial inhibition of endothelial carbonic anhydrase. The distribution of capillary transit times was computed from a model of CO2 production in the capillary bed and the observed rates and volumes of acetylene and carbon dioxide excretion. The recovered distributions indicate that there is a fairly wide distribution of capillary transit times (relative dispersion, 0.45) around the mean value of 1.71 s (+/- 0.53 [SD]). Only 10% of capillary transit times are less than one half of mean transit time. It is likely that gas exchange reaches equilibrium in the capillary bed except possibly during strenuous exercise or exposure to high altitude or in disease. PMID:8520770

Klocke, R A; Schünemann, H J; Grant, B J

1995-12-01

329

Polymer microfluidic device replacing fluids using only capillary force  

NASA Astrophysics Data System (ADS)

A novel polymer microfluidic device for self-wash using only capillary force is presented. A liquid filled in a reaction chamber is replaced by another liquid with no external actuation. All the fluidic actuations in the device is pre-programmed about time and sequence, and accomplished by capillary force naturally. Careful design is necessary for exact actions. The fluidic conduits were designed by the newly derived theoretical equations about the capillary stop pressure and flow time. Simulations using CFD-ACE+ were conducted to check the validity of theory and the performance of the chip. These analytic results were consistent with experimental ones. The chip was made of polymers for the purpose of single use and low price. It was fabricated by sealing the hot-embossed PMMA substrate with a PET film. For simpler fabrication, the chip was of a single height. The embossing master was produced from a nickel-electroplating on a SU8-patterned Ni-plate followed by CMP. The contact angles of liquids on substrates were manipulated through the mixing of surfactants, and the temporal variations were monitored for a more exact design. The real actuation steps in experiment revealed the stable performance of selfwash, and coincided well with the designed ones. The presented microfluidic method can be applicable to other LOCs of special purposes through simple modification. For example, array or serial types would be possible for multiple selfwashes.

Chung, Kwang Hyo; Lee, Dae Sik; Yang, Haesik; Kim, Sung Jin; Pyo, Hyun Bong

2005-02-01

330

Treatment of septic tank effluents by a full-scale capillary seepage soil biofiltration system.  

PubMed

The purpose of this study is to evaluate the efficiency of septic tank effluent treatment by an underground capillary seepage soil biofiltration system in a suburban area of Taipei, Taiwan. In contrast to traditional subsurface wastewater infiltration systems, capillary seepage soil biofiltration systems initially draw incoming influent upwards from the distribution pipe by capillary and siphonage actions, then spread influent throughout the soil biofiltration bed. The underground capillary seepage soil biofiltration system consists of a train of underground treatment units, including one wastewater distribution tank, two capillary seepage soil biofiltration units in series, and a discharge tank. Each capillary seepage soil biofiltration unit contains one facultative digestion tank and one set of biofiltration beds. At the flow rate of 50 m3/day, average influent concentrations of biochemical oxygen demand (BOD), suspended solid (SS), ammonia nitrogen (NH3-N), and total phosphates (TP), were 36.15 mg/L, 29.14 mg/L, 16.05 mg/L, and 1.75 mg/L, respectively. After 1.5 years of system operation, the measured influent and effluent results show that the treatment efficiencies of the soil biofiltration system for BOD, SS, NH3-N, TP, and total coliforms are 82.96%, 60.95%, 67.17%, 74.86%, and 99.99%, respectively. PMID:19326671

Fan, Chihhao; Chang, Fang-Chih; Ko, Chun-Han; Teng, Chia-Ji; Chang, Tzi-Chin; Sheu, Yiong-Shing

2009-03-01

331

Use of dynamically coated capillaries with added cyclodextrins for the analysis of opium using capillary electrophoresis  

Microsoft Academic Search

A rapid, precise, accurate, and robust method using capillary electrophoresis (CE) with dynamically coated capillaries for the analysis of the major opium alkaloids in opium is presented. Dynamic coating of the capillary surface is accomplished using a commercially available reagent kit (polycation coating followed by polyanion coating). The addition of dual cyclodextrins (hydroxypropyl-?-cyclodextrin and dimethyl-?-cyclodextrin) to the run buffer imparts

Ira S Lurie; Sini Panicker; Patrick A Hays; Agnes D Garcia; Bryan L Geer

2003-01-01

332

Electromigration dispersion in capillary electrophoresis.  

PubMed

In a previous paper (Ghosal and Chen in Bull. Math. Biol. 72:2047, 2010), it was shown that the evolution of the solute concentration in capillary electrophoresis is described by a nonlinear wave equation that reduced to Burger's equation if the nonlinearity was weak. It was assumed that only strong electrolytes (fully dissociated) were present. In the present paper, it is shown that the same governing equation also describes the situation where the electrolytic buffer consists of a single weak acid (or base). A simple approximate formula is derived for the dimensionless peak variance which is shown to agree well with published experimental data. PMID:22147104

Chen, Zhen; Ghosal, Sandip

2011-12-07

333

WETTABILITY ALTERATION OF POROUS MEDIA TO GAS-WETTING FOR IMPROVING PRODUCTIVITY AND INJECTIVITY IN GAS-LIQUID FLOWS  

SciTech Connect

Wettability alteration to intermediate gas-wetting in porous media by treatment with FC-759, a fluoropolymer polymer, has been studied experimentally. Berea sandstone was used as the main rock sample in our work and its wettability before and after chemical treatment was studied at various temperatures from 25 to 93 C. We also studied recovery performance for both gas/oil and oil/water systems for Berea sandstone before and after wettability alteration by chemical treatment. Our experimental study shows that chemical treatment with FC-759 can result in: (1) wettability alteration from strong liquid-wetting to stable intermediate gas-wetting at room temperature and at elevated temperatures; (2) neutral wetting for gas, oil, and water phases in two-phase flow; (3) significant increase in oil mobility for gas/oil system; and (4) improved recovery behavior for both gas/oil and oil/water systems. This work reveals a potential for field application for improved gas-well deliverability and well injectivity by altering the rock wettability around wellbore in gas condensate reservoirs from strong liquid-wetting to intermediate gas-wetting.

Abbas Firoozabadi

2003-12-01

334

WETTABILITY ALTERATION OF POROUS MEDIA TO GAS-WETTING FOR IMPROVING PRODUCTIVITY AND INJECTIVITY IN GAS-LIQUID FLOWS  

SciTech Connect

The wettability of Berea and chalk samples for gas-oil and gas-water fluids were altered from strong liquid-wetting to intermediate gas-wetting. Two polymers, FC-722 and FC-759, were used to alter the wettability. FC-759 is soluble in water and some 20 times less expensive than FC-722. Gas and liquid relative permeabilities were measured before and after wettability alteration. The results demonstrate a significant increase in liquid-phase relative permeability. Gas-phase relative permeability for a fixed saturation may increase or decrease. However, because of the very high liquid mobility and reduced liquid saturation, the gas mobility also increases for a fixed pressure drop. A number of liquid injectivity tests were also carried out. The results reveal that the liquid-phase mobility can increase significantly when the wettability of rocks is altered from strong liquid-wetting to intermediate gas-wetting. All the results show clearly that the application of wettability alteration to intermediate gas-wetting may significantly increase deliverability in gas condensate reservoirs.

Abbas Firoozabadi

2001-10-15

335

Enhancement of surface wettability via the modification of microtextured titanium implant surfaces with polyelectrolytes.  

PubMed

Micrometer- and submicrometer-scale surface roughness enhances osteoblast differentiation on titanium (Ti) substrates and increases bone-to-implant contact in vivo. However, the low surface wettability induced by surface roughness can retard initial interactions with the physiological environment. We examined chemical modifications of Ti surfaces [pretreated (PT), R(a) ? 0.3 ?m; sand blasted/acid etched (SLA), R(a) ? 3.0 ?m] in order to modify surface hydrophilicity. We designed coating layers of polyelectrolytes that did not alter the surface microstructure but increased surface ionic character, including chitosan (CHI), poly(L-glutamic acid) (PGA), and poly(L-lysine) (PLL). Ti disks were cleaned and sterilized. Surface chemical composition, roughness, wettability, and morphology of surfaces before and after polyelectrolyte coating were examined by X-ray photoelectron spectroscopy (XPS), contact mode profilometry, contact angle measurement, and scanning electron microscopy (SEM). High-resolution XPS spectra data validated the formation of polyelectrolyte layers on top of the Ti surface. The surface coverage of the polyelectrolyte adsorbed on Ti surfaces was evaluated with the pertinent SEM images and XPS peak intensity as a function of polyelectrolyte adsorption time on the Ti surface. PLL was coated in a uniform thin layer on the PT surface. CHI and PGA were coated evenly on PT, albeit in an incomplete monolayer. CHI, PGA, and PLL were coated on the SLA surface with complete coverage. The selected polyelectrolytes enhanced surface wettability without modifying surface roughness. These chemically modified surfaces on implant devices can contribute to the enhancement of osteoblast differentiation. PMID:21513319

Park, Jung Hwa; Schwartz, Zvi; Olivares-Navarrete, Rene; Boyan, Barbara D; Tannenbaum, Rina

2011-04-22

336

Capillary versus venous bedside blood glucose estimations  

Microsoft Academic Search

Objectives: To determine the mean difference and correlation between capillary and venous bedside glucose estimation in comparison to laboratory blood glucose analysis in emergency department (ED) patients.Methods: Blood glucose levels were synchronously analysed using a bedside blood glucometer on capillary and venous derived samples from consenting ED patients aged >12 years. The venous sample was sent for comparative testing using

R Boyd; B Leigh; P Stuart

2005-01-01

337

Blood Flow in the Capillary Bed.  

National Technical Information Service (NTIS)

A general survey of recent works on capillary blood flow is given. Some details are presented for two problems: the problem of deformation of the flexible red blood cells, their motion in the capillary blood vessels and the pressure drop due to the red ce...

Y. C. Fung

1969-01-01

338

Dumbbell-Shaped Epidural Capillary Hemangioma  

Microsoft Academic Search

Summary: We report a case of a purely epidural capillary hemangioma of the thoracic spine with foraminal exten- sion. Epidural hemangiomas are rare; only a few cases of dumbbell-shaped ones have been reported, and all were cavernous. MR imaging showed characteristic findings of a capillary hemangioma, which are also consistent with other epidural lesions such as neuromas or meningiomas. Hemangiomas

Bruno Badinand; Christophe Morel; Nicolas Kopp; A. Tran; Francois Cotton

339

Soda-glass capillary plate gas detector  

Microsoft Academic Search

A new capillary plate (CP) has been developed for a hole-type micropattern gas detector. The plate consists of a bundle of fine soda-glass capillaries with a diameter of 100 ?m and a length of 1 mm. The electrodes on the surfaces of both ends of CP were coated with Inconel metal. The plate is similar to a conventional CP, except

Fuyuki Tokanai; Takuji Atsumi; Shuichi Gunji; Teruyuki Okada; Hirohisa Sakurai

2005-01-01

340

Speciation of Metal Ions by Capillary Electrophoresis  

Microsoft Academic Search

The speciation of metal ions by capillary electrophoresis is an important area for environmental chemists. The speciation of metal ions by capillary electrophoresis in different matrices is reviewed. Various aspects of speciation such as sample pretreatment, metal ion complexation, detection, detection limit, choice of electrolytes, etc. have been described. Suggestions to improve the application of CE for the speciation of

Imran Ali; Hassan Y. Aboul-Enein

2002-01-01

341

Wettability of metallic glass alloys by two tin-based solders  

Microsoft Academic Search

The wettability of 95Sn-5Sb (wt-%) and 96.5Sn-3.5Ag solder alloys on rapidly solidified metal ribbons of compositions: 92Fe-3B-5Si, 81Co-4Fe-1Ni-4Mo-3B-7Si, and 82Co-5Fe-1Ni-3B-9Si was analyzed by the meniscometer\\/wetting balance technique. Two organic acid fluxes and an inorganic acid flux were evaluated. The substrate surfaces received only a solvent degreasing treatment. The 96.5Sn-3.5Ag and 95Sn-5Sb solders exhibited fair to good wetting with contact angles

P. T. Vianco; F. M. Hosking; J. A. Rejent

1994-01-01

342

General equation of wettability: A tool to calculate the contact angle for a rough surface  

NASA Astrophysics Data System (ADS)

This work introduces a mathematical tool, namely general equation of wettability, which simplifies the determination of the contact angle for rough surfaces. A free energy minimization method is applied to an intermediate wetting state with partial liquid penetration into roughness valleys in addition to the well-known states of Wenzel and Cassie wetting. A wetting parameter is coined, which stands out as a fingerprint of a particular wetting state of a surface topology. Substitution of the appropriate wetting parameter returns the Cassie and Wenzel equations, while an implicit solution is presented for the intermediate state, which is consistent with energy minimization.

Sarkar, Anjishnu; Kietzig, Anne-Marie

2013-06-01

343

Self-erasing and rewritable wettability patterns on ZnO thin films  

NASA Astrophysics Data System (ADS)

Self-erasing patterns allow a substrate to be patterned multiple times or could store temporary information for secret communications, and are mostly based on photochromic molecules to change the color of the pattern. Herein we demonstrate self-erasing patterns of wettability on thin ZnO films made by atomic layer deposition. Hydrophilic patterns are written using UV light and decay spontaneously, i.e. become hydrophobic, or are erased aided by vacuum conditions or heat. We demonstrate that these patterns can be applied for channels to confine flow of water without physical walls.

Kekkonen, Ville; Hakola, Antti; Kajava, Timo; Sahramo, Elina; Malm, Jari; Karppinen, Maarit; Ras, Robin H. A.

2010-07-01

344

Superhydrophobic and superoleophilic nanoparticle film: synthesis and reversible wettability switching behavior.  

PubMed

The present work describes a one-step facile spray deposition process for the fabrication of superhydrophobic and superoleophilic nanoparticle film. The film shows fast response wettability transition between superhydrophobicity and hydrophilicity. The reversible superhydrophobicity to hydrophilicity switching can be easily carried out by adjusting the temperature. The film also demonstrates oil uptake ability and can selectively adsorb oil floating on water surface. Furthermore, the film surface shows the antifouling performance for organic solvents, which can self-remove the organic solvents layer and recover its superhydrophobic behavior. The advantage of the present approach is that the damaged film can be easily repaired by spraying again. PMID:22329929

Zhang, Xia; Guo, Yonggang; Zhang, Pingyu; Wu, Zhishen; Zhang, Zhijun

2012-03-09

345

Facile fabrication of superhydrophobic ZnO nanoparticle surfaces with erasable and rewritable wettability  

NASA Astrophysics Data System (ADS)

In this article, ZnO nanoparticle surfaces have been fabricated successfully by a simple spray-coating method without limitations the shape and size of substrates. After being chemically modified with stearic acid, the wettability of ZnO surfaces changed from superhydrophilicity to superhydrophobicity. Furthermore, the superhydrophobicity could be erased and rewrote by the alternation of plasma or heat treatment and stearic acid coating. The process has been repeated with full reproducibility more than eight times, demonstrating that the ZnO surfaces exhibit good erasable and rewritable superhydrophobicity.

Li, Jian; Wan, Hongqi; Liu, Xiaohong; Ye, Yinping; Zhou, Huidi; Chen, Jianmin

2012-09-01

346

Reversible wettability of electron-beam deposited indium-tin-oxide driven by ns-UV irradiation  

NASA Astrophysics Data System (ADS)

Indium tin oxide (ITO) is one of the most widely used semiconductor oxides in the field of organic optoelectronics, especially for the realization of anode contacts. Here the authors report on the control of the wettability properties of ITO films deposited by reactive electron beam deposition and irradiated by means of nanosecond-pulsed UV irradiation. The enhancement of the surface water wettability, with a reduction of the water contact angle larger than 50°, is achieved by few tens of seconds of irradiation. The analyzed photo-induced wettability change is fully reversible in agreement with a surface-defect model, and it can be exploited to realize optically transparent, conductive surfaces with controllable wetting properties for sensors and microfluidic circuits.

Persano, Luana; Del Carro, Pompilio; Pisignano, Dario

2012-04-01

347

Fabrication of noble-metal catalysts with a desired surface wettability and their applications in deciphering multiphase reactions.  

PubMed

Noble-metal Pd and Pt catalysts with a wide range of surface wettability were fabricated through an electrochemical approach and were characterized with scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and atomic force microscopy. The importance of surface wettability of solid catalysts in multiphase reactions-especially their correlation to the nature of the studied chemical system-was investigated by reducing oxygen in an alkaline solution and oxidizing hydrogen peroxide and sodium formate in alkaline or buffered solutions at the as-prepared catalysts. These experiments illustrate that the nature of a multiphase reaction plays a critical role in determining the influence of surface wettability on the catalyst performance, providing a unique approach to decipher the reaction process. The investigation allows us to gain new insights into the electrochemical oxidation of sodium formate. PMID:23574422

Wang, Demeng; Wang, Shun; Jin, Huile; Zhang, Weiming; Yang, Yun; Sun, Aiping; Tang, Tiandi; Wang, Jichang

2013-04-23

348

Reversible wettability of electron-beam deposited indium-tin-oxide driven by ns-UV irradiation  

SciTech Connect

Indium tin oxide (ITO) is one of the most widely used semiconductor oxides in the field of organic optoelectronics, especially for the realization of anode contacts. Here the authors report on the control of the wettability properties of ITO films deposited by reactive electron beam deposition and irradiated by means of nanosecond-pulsed UV irradiation. The enhancement of the surface water wettability, with a reduction of the water contact angle larger than 50 deg., is achieved by few tens of seconds of irradiation. The analyzed photo-induced wettability change is fully reversible in agreement with a surface-defect model, and it can be exploited to realize optically transparent, conductive surfaces with controllable wetting properties for sensors and microfluidic circuits.

Persano, Luana [NNL, National Nanotechnology Laboratory of CNR-Istituto Nanoscienze, Universita del Salento, via Arnesano, I-73100 Lecce (Italy); Center for Biomolecular Nanotechnologies UNILE, Istituto Italiano di Tecnologia, Via Barsanti, I-73010 Arnesano-LE (Italy); Del Carro, Pompilio [NNL, National Nanotechnology Laboratory of CNR-Istituto Nanoscienze, Universita del Salento, via Arnesano, I-73100 Lecce (Italy); Pisignano, Dario [NNL, National Nanotechnology Laboratory of CNR-Istituto Nanoscienze, Universita del Salento, via Arnesano, I-73100 Lecce (Italy); Center for Biomolecular Nanotechnologies UNILE, Istituto Italiano di Tecnologia, Via Barsanti, I-73010 Arnesano-LE (Italy); Dipartimento di Matematica e Fisica ''Ennio De Giorgi'', Universita del Salento, via Arnesano, I-73100 Lecce (Italy)

2012-04-09

349

CREOSOTE WETTABILITY REVIEW AND EVALUATION AT A PORTION OF THE CABOT CARBON\\/KOPPERS SUPERFUND SITE  

Microsoft Academic Search

Creosote in the subsurface is acted on by three forces: (1) gravitational (pressure due to gravity), (2) capillary (capillary pressure) and (3) hydraulic (also known as viscous force or hydrodynamic pressure). Due to its high viscosity (~10 cp, and higher with weathering) and similar density (~1.03 to 1.10 g\\/cc) relative to water (1 cp and 1.0 g\\/cc), creosote movement and

Robert M. Cohen; James W. Mercer; Michael Slenska; Mitchell Brourman

350

Integrated, Multi-Scale Characterization of Imbibition and Wettability Phenomena Using Magnetic Resonance and Wide-Band Dielectric Measurements  

SciTech Connect

The petrophysical properties of rocks, particularly their relative permeability and wettability, strongly influence the efficiency and the time-scale of all hydrocarbon recovery processes. However, the quantitative relationships needed to account for the influence of wettability and pore structure on multi-phase flow are not yet available, largely due to the complexity of the phenomena controlling wettability and the difficulty of characterizing rock properties at the relevant length scales. This project brings together several advanced technologies to characterize pore structure and wettability. Grain-scale models are developed that help to better interpret the electric and dielectric response of rocks. These studies allow the computation of realistic configurations of two immiscible fluids as a function of wettability and geologic characteristics. These fluid configurations form a basis for predicting and explaining macroscopic behavior, including the relationship between relative permeability, wettability and laboratory and wireline log measurements of NMR and dielectric response. Dielectric and NMR measurements have been made show that the response of the rocks depends on the wetting and flow properties of the rock. The theoretical models can be used for a better interpretation and inversion of standard well logs to obtain accurate and reliable estimates of fluid saturation and of their producibility. The ultimate benefit of this combined theoretical/empirical approach for reservoir characterization is that rather than reproducing the behavior of any particular sample or set of samples, it can explain and predict trends in behavior that can be applied at a range of length scales, including correlation with wireline logs, seismic, and geologic units and strata. This approach can substantially enhance wireline log interpretation for reservoir characterization and provide better descriptions, at several scales, of crucial reservoir flow properties that govern oil recovery.

Mukul M. Sharma; Steven L. Bryant; Carlos Torres-Verdin; George Hirasaki

2007-09-30

351

Effects of Er: YAG laser irradiation on wettability, surface roughness, and biocompatibility of SLA titanium surfaces: an in vitro study.  

PubMed

The erbium: yttrium-aluminum-garnet (Er: YAG) laser has been introduced as an effective method in the decontamination of implant surfaces. Data concerning the effects of the Er: YAG laser on the biological and surface properties of titanium are conflicting. Cellular behavior is greatly affected by surface properties, including composition, roughness, wettability, and morphology of the titanium surface. The aim of this study was to investigate the influence of the Er: YAG laser on the biocompatibility, surface roughness, and wettability of sandblasted and acid-etched (SLA) titanium surfaces. Twenty-one SLA titanium disks were irradiated by the Er: YAG laser at a pulse energy of 100 mJ, with a pulse frequency of 10 Hz under water irrigation for 1 min. Cell viability, surface roughness, and wettability alterations were evaluated. Thirteen nonirradiated SLA disks were used as the control groups. Human osteoblast-like SaOs-2 cells were seeded onto the disks in culture media. Cell viability was evaluated using the methylthiazol tetrazolium assay. The surface roughness and wettability of the test and control groups were measured using profilometer and tensiometer devices, respectively. A significantly higher cell viability rate was observed in the test group (p?=?0.032). The surface roughness was significantly reduced in the test group compared with the control group (p?=?0.008). The surface wettability was significantly higher in the test group (p?=?0.004). Within the limits of this study, the application of the Er: YAG laser with the previously described properties did not appear to have adverse effects on the biocompatibility of the SLA titanium surfaces. Application of this laser decreased the surface roughness and increased the wettability of the SLA titanium surfaces. PMID:23760881

Ayobian-Markazi, Nader; Karimi, Mohammadreza; Safar-Hajhosseini, Ali

2013-06-13

352

Two-dimensional capillary electrophoresis: capillary isoelectric focusing and capillary zone electrophoresis with laser-induced fluorescence detection  

PubMed Central

Capillary isoelectric focusing and capillary zone electrophoresis are coupled with laser-induced fluorescence detection to create an ultrasensitive two-dimensional separation method for proteins. In this method, two capillaries are joined through a buffer filled interface. Separate power supplies control the potential at the injection end of the first capillary and at the interface; the detector is held at ground potential. Proteins are labeled with the fluorogenic reagent Chromeo P503, which preserves the isoelectric point of the labeled protein. The labeled proteins were mixed with ampholytes and injected into the first dimension capillary. A focusing step was performed with the injection end of the capillary at high pH and the interface at low pH. To mobilize components, the interface was filled with a high pH buffer, which was compatible with the second dimension separation. A fraction was transferred to the second dimension capillary for separation. The process of fraction transfer and second dimension separation was repeated two dozen times. The separation produced a spot capacity of 125.

Dickerson, Jane A.; Ramsay, Lauren M.; Dada, Oluwatosin O.; Cermak, Nathan

2011-01-01

353

Capillary Separation: Micellar Electrokinetic Chromatography  

NASA Astrophysics Data System (ADS)

Micellar electrokinetic chromatography (MEKC), a separation mode of capillary electrophoresis (CE), has enabled the separation of electrically neutral analytes. MEKC can be performed by adding an ionic micelle to the running solution of CE without modifying the instrument. Its separation principle is based on the differential migration of the ionic micelles and the bulk running buffer under electrophoresis conditions and on the interaction between the analyte and the micelle. Hence, MEKC's separation principle is similar to that of chromatography. MEKC is a useful technique particularly for the separation of small molecules, both neutral and charged, and yields high-efficiency separation in a short time with minimum amounts of sample and reagents. To improve the concentration sensitivity of detection, several on-line sample preconcentration techniques such as sweeping have been developed.

Terabe, Shigeru

2009-07-01

354

Capillary electrophoresis for monitoring bioprocesses.  

PubMed

Chemical characterization and monitoring of fermentation broths and cell culture media provide significant information on the changes occurring within these complex and dynamic systems. Analytical methods based on CE in capillaries and microchips are attractive for integration in instrumental tools to obtain this critical data, improving the understanding and control of bioprocesses. In this review, the use of CE for chemical characterization and monitoring fermentations is discussed, organized by analyte class, including organic acids, pharmaceuticals, proteins, sugars, amino acids, and metabolites published between 1992 and October 2012. A section is dedicated to the roles CE plays throughout the wine making process, where applications range from characterization and increase in fundamental understanding of the fermentation to forensic applications, verifying the authenticity of the wine. PMID:23657993

Alhusban, Ala A; Breadmore, Michael C; Guijt, Rosanne M

2013-05-08

355

Determination of metalaxyl and identification of adjuvants in wettable powder pesticide technical formulas.  

PubMed

Foliar runoff is one of the most important processes affecting off-target movement of fungicides. In this way, Ridomil Gold Plus and Ridomil Gold MZ are two types of wettable powder technical formulations which contain metalaxyl and they are used for such a purpose. A method for quantitative determination of metalaxyl in pesticide formulas has been developed, validated, and subsequently applied to Ridomil Gold Plus and Ridomil Gold MZ. The method employs liquid-liquid extraction followed by liquid chromatography coupled with UV detection (LC-UV), using gas chromatography coupled with mass spectrometry as confirmation technique and to carry out a screening of organic adjuvants of these two selected pesticide formulas. Metalaxyl of 26.5 and 41 g/kg was detected in Ridomil Gold Plus and Ridomil Gold MZ, close to the manufacture specified level of 25 and 40 g/kg, respectively. Activator and utility adjuvants were detected in these two wettable powder technical formulations. Only methyl-ester-based surfactants were found within the group of nonionic surfactants, but the long-term fates of most adjuvants in soils and elsewhere in the environment are largely unknown, partially because of the lack of long-term monitoring data. PMID:19194695

Pose-Juan, Eva; Rial-Otero, Raquel; Martínez-Carballo, Elena; López-Periago, Eugenio; Simal-Gándara, Jesús

2009-02-05

356

Laser pulse dependent micro textured calcium phosphate coatings for improved wettability and cell compatibility.  

PubMed

Surface wettability of an implant material is an important criterion in biological response as it controls the adsorption of proteins followed by attachment of cells to its surface. Hence, micro-textured calcium phosphate coatings with four length scales were synthesized on Ti-6Al-4V substrates by a laser cladding technique and their effects on wettability and cell adhesion were systematically evaluated. Microstructure and morphological evolutions of the coatings were studied using scanning electron and light optical microscopes respectively. The surface texture of coating defined in terms of a texture parameter was correlated to its wetting behavior. The contact angle of simulated body fluid measured by a static sessile drop technique, demonstrated an increased hydrophilicity with decreasing value of texture parameter. The influence of such textures on the in vitro bioactivity and in vitro biocompatibility were studied by the immersion of the samples in simulated body fluid and mouse MC3T3-E1 osteoblast-like cell culture respectively. PMID:20464459

Paital, Sameer R; He, Wei; Dahotre, Narendra B

2010-05-13

357

Wettability of metallic glass alloys by two tin-based solders  

SciTech Connect

The wettability of 95Sn-5Sb (wt-%) and 96.5Sn-3.5Ag solder alloys on rapidly solidified metal ribbons of compositions: 92Fe-3B-5Si, 81Co-4Fe-1Ni-4Mo-3B-7Si, and 82Co-5Fe-1Ni-3B-9Si was analyzed by the meniscometer/wetting balance technique. Two organic acid fluxes and an inorganic acid flux were evaluated. The substrate surfaces received only a solvent degreasing treatment. The 96.5Sn-3.5Ag and 95Sn-5Sb solders exhibited fair to good wetting with contact angles of 32 to 62 deg and 25 to 60 deg, respectively. The contact angle values were similar with the two organic acid fluxes and slightly lower with the inorganic acid solution. Although the surface morphology was different on the two faces of the ribbons, the contact angles of either surface for each ribbon were similar. The quality of the solder film remaining on the samples was largely dependent upon the particular solder-flux-substrate system with the exception of the inorganic flux for which dewetting was always observed. The solder-flux interfacial tension values depended upon the flux and solder alloy. Thermal annealing of the metallic glass caused a deterioration in wettability. Undetected changes to the thickness of the native surface oxide layer, or the thermally relaxed structure resulting from the heat treatment, were likely sources of the increased contact angle.

Vianco, P.T.; Hosking, F.M.; Rejent, J.A. (Sandia National Labs., Albuquerque, NM (United States). Center for Solder Science and Technology)

1994-07-01

358

Impact of wettability on pore-scale characteristics of residual nonaqueous phase liquids.  

PubMed

The objective of this paper was to investigate the impact of wettability of porous media on pore-scale characteristics of residual nonaqueous phase liquids (NAPLs). Synchrotron X-ray microtomography was used to obtain high-resolution three-dimensional images of fractionally wet sand systems with mean grain size of 250 microm. Pore-scale characteristics of NAPL blobs such as volume, lengths, interfacial areas, and sphericity index were computed using three-dimensional image processing algorithms. Four systems comprised of 100, 50, 25, and 0% NAPL-wet mass fractions containing the residual NAPL were imaged and analyzed. Findings indicate that spatial variation in wettability of porous media surfaces has a significant impact on pore-scale characteristics of residual NAPL blobs in saturated porous media systems. As the porous media comprises more water-wet surfaces, residual NAPL blobs increase in size and length due to the entrapment at large pore bodies. NAPL-water interfacial areas tend to increase as the NAPL-wet surface fractions increase in the systems. Overall residual NAPL saturations are less in fractionally wet systems and increase as the systems become more NAPL-wet or water-wet. PMID:19673267

Al-Raoush, Riyadh I

2009-07-01

359

The effect of oxygen vacancies on water wettability of a ZnO surface.  

PubMed

In this study, the effect of oxygen vacancies on the water wettability of a hydrated ZnO(100) surface has been examined via molecular dynamics simulations with a reactive force field (ReaxFF). The results show that the oxygen vacancies on the ZnO surface change the structures of the ZnO surface and subsequently its water adsorption capability. While a 1?:?1 ratio of water to hydroxyl is observed for a water monolayer absorbed on ZnO(100) without oxygen vacancies, additional water adsorption as coordinate hydroxyl that resides on the vacancy site and bonds with three lattice zinc atoms is observed on the surfaces with oxygen vacancies. The results also show that the energy of the interaction per unit area between water and the hydrated ZnO surface is 55.1% higher in the presence of the oxygen vacancies than that without oxygen vacancies. This leads to a water contact angle of ?115° for the hydrated ZnO(100) surface in the absence of vacancies and ?21° with vacancies. The wetting kinetics of a water droplet on a ZnO(100) surface with and without oxygen vacancies are compared with the diffusion-limited reactive wetting and molecular kinetics models, respectively. In addition, the ordering of the vacancy sites is found not to significantly affect the wettability of the ZnO(100) surface. PMID:23949186

Hu, Han; Ji, Hai-Feng; Sun, Ying

2013-08-15

360

Dynamic wettability of wood surface modified by acidic dyestuff and fixing agent  

NASA Astrophysics Data System (ADS)

Acidic dyestuffs can bring brilliant colors to the wood and fixing agents can avoid the color loss. They could change the surface wettability of wood, which impact the gluing process of veneers. In condition of the higher moisture content of wood, the rare veneers, the veneers dyed by acidic dyestuffs and the dyed veneers fixed by Chitosan were glued respectively by one-component wet-curing isocyanate adhesive and the contact angles (?) of the different gluing interfaces were measured. The dynamic wettability of these gluing interfaces was characterized by both the contact angle ? and the spreading-penetration parameter (K) calculated by ?. The results showed that the ?-values decreased significantly with the extension of time and the initial contact angles (?i) decreased with the moisture contents of veneers increasing, but the variation of the balance contact angles (?e) was reversed with ?i. When the moisture contents of veneers were same, the variation of ? of the rare veneers was minimal and the variation of ? of the fixed veneers was maximal. The K-values of these gluing interfaces all decreased significantly with the moisture contents of veneers increasing, but the variations of K were different. The wetting model describing the dynamic wetting process was established on the basis of these variations.

Wei, Shuangying; Shi, Junyou; Gu, Jiyou; Wang, Di; Zhang, Yanhua

2012-01-01

361

Mechanism of wettability transition in copper metal foams: From superhydrophilic to hydrophobic  

NASA Astrophysics Data System (ADS)

Hydrophilicity is a necessary condition for wicking materials such as copper metal foams used in heat pipes. Unfortunately hydrophilic copper metal foams become hydrophobic when exposed to room ambient air. This wettability transition is commonly explained by the formation of copper oxides on the surface; however copper oxides are known to be hydrophilic. An experimental study is conducted to explain this controversy. Effect of different atmospheres on the rate of hydrophilicity loss is studied by a novel approach which is to measure the spreading time of droplet on the foam surface. Also, surface characterization techniques such as XPS and TOF-SIMS are used to characterize the time dependent impact of the ambient air on the morphology and chemical composition of the copper metal foams. The hydrophobicity mechanism of copper metal foams is found to be dominated by surface chemistry and not its morphology (Wenzel type). Results show that oxidation is not the reason for this hydrophilic to hydrophobic change but rather, adsorption of volatile organic compounds (VOCs) on the copper foam's surface. This explanation is further supported by observing the same wettability change towards hydrophobicity when immersing hydrophilic copper metal foams in a liquid VOC (?-pinene).

Shirazy, Mahmood R. S.; Blais, Sonia; Fréchette, Luc G.

2012-06-01

362

Impact of Wettability on Pore-Scale Characteristics of Residual Nonaqueous Phase Liquids  

SciTech Connect

The objective of this paper was to investigate the impact of wettability of porous media on pore-scale characteristics of residual nonaqueous phase liquids (NAPLs). Synchrotron X-ray microtomography was used to obtain high-resolution three-dimensional images of fractionally wet sand systems with mean grain size of 250 {micro}m. Pore-scale characteristics of NAPL blobs such as volume, lengths, interfacial areas, and sphericity index were computed using three-dimensional image processing algorithms. Four systems comprised of 100, 50, 25, and 0% NAPL-wet mass fractions containing the residual NAPL were imaged and analyzed. Findings indicate that spatial variation in wettability of porous media surfaces has a significant impact on pore-scale characteristics of residual NAPL blobs in saturated porous media systems. As the porous media comprises more water-wet surfaces, residual NAPL blobs increase in size and length due to the entrapment at large pore bodies. NAPL-water interfacial areas tend to increase as the NAPL-wet surface fractions increase in the systems. Overall residual NAPL saturations are less in fractionally wet systems and increase as the systems become more NAPL-wet or water-wet.

Al-Raoush, Riyadh I.; (Southern)

2009-07-31

363

Capillary supercritical fluid chromatography of pyrrolizidine alkaloids.  

PubMed

The application of capillary supercritical fluid chromatography (SFC) for the separation of pyrrolizidine alkaloids (PAs) is examined. Most of these compounds are powerful toxins. Because they are present in at least 3% of all flowering plants, they are responsible for serious losses of livestock and human disease. Capillary SFC, with its high separation efficiency, is shown to be an excellent method for the chromatographic analysis of complex PA mixtures. Complete separation of the PAs of the retronecine and otonecine family has been achieved by pressure-programmed capillary SFC. The operating conditions are mild enough to prevent thermal decomposition of the alkaloids during analysis. PMID:3117819

Holzer, G; Zalkow, L H; Asibal, C F

1987-07-29

364

Capillary force repels coffee-ring effect  

NASA Astrophysics Data System (ADS)

When a coffee drop dries on a solid surface, it leaves a ringlike deposit along the edge and this is known as the “coffee-ring effect.” We find a different motion of particles repelling the coffee-ring effect in drying droplets; the motion of particles that is initially toward the edge by the coffee-ring effect is reversed toward the center by a capillary force. The reversal takes place when the capillary force prevails over the outward coffee-ring flow. We discuss the geometric constraints for the capillary force and the reverse motion. Our findings of reversal phenomena would be important in many scenarios of drying colloidal fluids.

Weon, Byung Mook; Je, Jung Ho

2010-07-01

365

Capillary bundle model of hydraulic conductivity for frozen soil  

Microsoft Academic Search

We developed a capillary bundle model to describe water flow in frozen soil. We assume that the soil can be represented as a bundle of cylindrical capillaries. We consider that the freezing point in the capillaries is depressed according to the Gibbs-Thomson effect and that when stable ice forms in a capillary, the ice forms in the center of the

Kunio Watanabe; Markus Flury

2008-01-01

366

A Wettability Switchable Surface Driven by Electrostatic Induced Surface Morphology Change Without Energy Interference On Reagents in Droplets  

Microsoft Academic Search

A novel surface wettability switchable device was successfully demonstrated by changing the surface morphology to induce contact angle change. The surface morphology transformation carried out from the deflection of thin PDMS membrane, driven by electrostatic force, can dynamically change the surface contact angle from 131 ° to 152 ° based on the contact area variation. The electrostatic energy can be

Ting-Hsuan Chen; Yun-Ju Chuang; Fan-Gang Tseng

2006-01-01

367

Self-assembly and hierarchical patterning of aligned organic nanowire arrays by solvent evaporation on substrates with patterned wettability.  

PubMed

The controlled growth and alignment of one-dimensional organic nanostructures at well-defined locations considerably hinders the integration of nanostructures for electronic and optoelectronic applications. Here, we demonstrate a simple process to achieve the growth, alignment, and hierarchical patterning of organic nanowires on substrates with controlled patterns of surface wettability. The first-level pattern is confined by the substrate patterns of wettability. Organic nanostructures are preferentially grown on solvent wettable regions. The second-level pattern is the patterning of aligned organic nanowires deposited by controlling the shape and movement of the solution contact lines during evaporation on the wettable regions. This process is controlled by the cover-hat-controlled method or vertical evaportation method. Therefore, various new patterns of organic nanostructures can be obtained by combing these two levels of patterns. This simple method proves to be a general approach that can be applied to other organic nanostructure systems. Using the as-prepared patterned nanowire arrays, an optoelectronic device (photodetector) is easily fabricated. Hence, the proposed simple, large-scale, low-cost method of preparing patterns of highly ordered organic nanostructures has high potential applications in various electronic and optoelectronic devices. PMID:23742204

Bao, Rong-Rong; Zhang, Cheng-Yi; Zhang, Xiu-Juan; Ou, Xue-Mei; Lee, Chun-Sing; Jie, Jian-Sheng; Zhang, Xiao-Hong

2013-06-06

368

Wettability of Ti 3SiC 2 by Ag-Cu and Ag-Cu-Ti melts  

Microsoft Academic Search

Recently, the ternary carbide Ti 3SiC 2 has gained much attention due to its unique characteristics combining the properties of metals and ceramics (i. e., a low density, decent thermal and electrical conductivities, an excellent thermal shock resistan ce, a good machinability, damage tolerance, low friction and so on). The present study describes an investigation of the wettability in high

O. Dezellus; R. Voytovych; A. P. H. Li; G. Constantin; F. Bosselet

369

Wettability between TiN, TiC Containing Carbon Composite Refractory and Molten Slag or Hot Metal.  

National Technical Information Service (NTIS)

In order to develop a new-type TiC-TiN containing carbon composite refractory that improves the service life of blast furnace hearths, the wettability between the carbon refractory and molten slag or metal has been measured. It was determined that the car...

Y. X. Shi Y. Li W. Z. Wang

1995-01-01

370

Analysis of Simple Carbohydrates by Capillary Electrophoresis and Capillary Electrophoresis–Mass Spectrometry  

Microsoft Academic Search

\\u000a An overview of the application of capillary electrophoresis and ­capillary electrophoresis–mass spectrometry in the analysis\\u000a of simple carbohydrates without any previous derivatization step is given. Besides electrolyte systems for ­carbohydrate separation,\\u000a detection techniques employed in capillary electrophoresis, such as ­spectrophotometric detection, electrochemical detection,\\u000a and mass spectrometric ­detection, are discussed, as are less common detection techniques. Thus, the chapter focuses on

Christian W. Klampfl; Markus Himmelsbach; Wolfgang Buchberger

371

Applicability of chemically modified capillaries in chiral capillary electrophoresis for methamphetamine profiling.  

PubMed

We examined the applicability of chemically modified capillaries on the chiral capillary electrophoresis of essential compounds for methamphetamine (MA) profiling (MA, amphetamine, ephedrine, pseudoephedrine, norephedrine, and norpseudoephedrine) using highly sulfated ?-cyclodextrin as a chiral selector. Four types of chemically modified capillaries, namely, FunCap-CE/Type D (possessing diol groups), Type A (amino groups), Type C (carboxyl groups), and Type S (sulfate groups), were evaluated. Repeatability, speed, and good chiral resolution sufficient for routine MA profiling were achieved with the Type S capillary. PMID:23422168

Iwata, Yuko T; Mikuma, Toshiyasu; Kuwayama, Kenji; Tsujikawa, Kenji; Miyaguchi, Hajime; Kanamori, Tatsuyuki; Inoue, Hiroyuki

2013-02-16

372

Capillary electrochromatography using fibers as stationary phases.  

PubMed

Fiber-packed capillary columns have been evaluated in chromatographic performance in capillary electrochromatography (CEC). The change of electroosmotic flow (EOF) velocity and selectivity using different kinds of fiber materials was examined. Although the EOF velocity among the different fiber packed columns was almost the same, retention of parabens was larger on the Kevlar-packed column than on the Zylon-packed one, and was larger on the as-span-type fiber-packed column than on the high-modulus-type packed one. Using 200 microm ID x 5 cm Kevlar packed column combined with a 100 microm ID x 20 cm precolumn capillary and a 530 microm ID x 45 cm postcolumn capillary, the separation of three parabens within 30 s was achieved. Other compounds were also separated in a few minutes by the fiber-packed CEC method. PMID:11669512

Jinno, K; Watanabe, H; Saito, Y; Takeichi, T

2001-10-01

373

Capillary rise in thin porous media  

SciTech Connect

A theory for the equilibrium capillary rise inside a thin porous medium is presented. It is shown that the height of rise depends on the thickness of the medium and is lower than the corresponding value for a infinitely thick slab. The extent of deviation is shown to depend on all the parameters which characterize the system. For high true contact angles, the capillary rise in a thin porous medium may be only a very small fraction of the value for a thick one. This phenomenon is explained in terms of the reexposure effect, which stems from the exposure of the liquid rising inside the porous medium to the outside fluid, through the pores in the side surfaces. A symmetry with respect to the axis of 90{degree} for the true contact angle is identified, so that the results for capillary rise can be also applied to capillary depression.

Marmur, A. (Technion-Israel Institute of Technology, Haifa (Israel))

1989-06-15

374

Capillary underwater discharges in repetitive pulse regime  

NASA Astrophysics Data System (ADS)

In this study a capillary underwater discharge, that is sustained with AC (50 Hz) voltages up to 7.5 kV, is investigated. In a capillary discharge scheme, the current is, at some point along its path between two submerged electrodes, flowing through a narrow elongated bore in a dielectric material. When the current density is sufficiently high, local boiling and subsequent vapour breakdown results in the formation of a plasma within this capillary. At the same time the capillary emits an intense jet of vapour bubbles. Time-dependent electrical current, voltage and light emission curves are recorded for discharges in solutions of NaCl in distilled water and reveal different discharge regimes, depending on the conductivity and the excitation voltage, ranging from repetitive microsecond discharge pulses to a quasi-continuous discharge with a glow-like voltage-current characteristic.

de Baerdemaeker, F.; Monte, M.; Leys, C.

2004-03-01

375

Capillary Assisted Thermosyphon For Shipboard Electronics Cooling.  

National Technical Information Service (NTIS)

Recent advances in capillary pumped loop technology were incorporated into the design of a vertical flat plate evaporator for cooling high power electronics aboard naval vessels. This investigation included the design, fabrication, and experimentation of ...

E. H. Larsen

2003-01-01

376

Characterising Microstructured Materials Using a Capillary Rheometer  

NASA Astrophysics Data System (ADS)

A parallel plate and capillary rheometer have been used to rheologically characterize an Australian hard wheat flour-water dough over an extensive range of shear rates (10-3-104 s-1). Torsional measurements showed that the shear viscosity of dough increased with strain to a maximum value then decreased, suggesting a breakdown of the dough structure. This was consistent with other published data on doughs. Capillary experiments revealed the shear thinning behavior of dough, which was described by a power-law model. The wall slip behavior of dough was examined, revealing a critical shear stress at which slip occurs for a 1 mm diameter capillary. The capillary data was best linked to the torsional data at low strain values (~0.1) as expected given the nature of sampling in the two rheometers.

Hicks, Christopher I.; See, Howard; Arabo, Emad Y. M.

2008-07-01

377

RF Liquid Measurement Of Capillary Tubes  

NASA Astrophysics Data System (ADS)

Electromagnetic measurements of capillary tubes containing liquids can reveal solution properties for industrial, biological, and chemical processes. An analytical model was created for a perpendicular arrangement of SMA cables and a capillary tube. Numerical simulations in Ansoft High Frequency Structural Simulator were performed on the simple arrangement. The transmission parameters of the capillary tube were simulated between two lumped ports over a frequency range from 1 GHz to 20 GHz. Sensitivity of the transmission parameters to solution conditions were calculated for DI water and other variations of conductivity and permittivity. Experiments were performed on a capillary tube in a perpendicular arrangement using an HP 8720B Network Analyzer. The transmission parameters were measured and the resulting data was compared with the simulations. This measurement method can be adapted to different tube and solution conditions.

Poudyal, Bashudev; Mazzeo, Brian; Warnick, Karl

2009-10-01

378

Scintigraphy for Pulmonary Capillary Protein Leak.  

National Technical Information Service (NTIS)

Pulmonary gamma scintigraphy is a rapid, non-invasive technique for measuring a pulmonary capillary protein leak in ARDS. In these studies, the method demonstrated that the acute anesthetized lung lymph fistula sheep model was associated with a significan...

H. J. Sugerman J. L. Tatum J. I. Hirsch A. M. Strash

1983-01-01

379

CAPILLARY BARRIERS IN UNSATURATED FRACTURED ROCKS  

SciTech Connect

This work presents modeling studies investigating the effects of capillary barriers on fluid-flow and tracer-transport processes in the unsaturated zone of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. These studies are designed to identify factors controlling the formation of capillary barriers and to estimate their effects on the extent of possible large-scale lateral flow in unsaturated fracture rocks. The modeling approach is based on a continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. Flow processes in fractured porous rock are described using a dual-continuum concept. In addition, approximate analytical solutions are developed and used for assessing capillary-barrier effects in fractured rocks. This study indicates that under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary-barrier effects exist for significantly diverting moisture flow.

Y.S. Wu; W. Zhang; L. Pan; J. Hinds; G. Bodvarsson

2000-10-01

380

Capillary membranes for separation of dye particles  

Microsoft Academic Search

The study aimed at investigating the suitability of capillary modules to the decolorization of both synthetic and actual dye solutions by ultrafiltration. The process involved capillary membranes made of polysulfone and modified polysulfone. Membrane modules (UFTA PS10; UFTA PS30, and UFTA PSA50) of various molecular cut-off were applied. Comparable studies including the effect of hydraulic conditions existing in the system

Katarzyna Majewska-Nowak; Ma?gorzata Kabsch-Korbutowicz; Tomasz Winnicki

1996-01-01

381

Capillary electrochromatography: operating characteristics and enantiomeric separations  

Microsoft Academic Search

Some fundamental aspects of capillary electrochromatography (CEC) (electroosmotic flow, capacity factor, plate height) were studied by carrying out the separation of some neutral compounds with capillaries packed with octadecylsilica particles (ODS). No loss of efficiency up to a linear electroosmotic velocity of 1.3 mm\\/s was observed for retained analytes (capacity factors varying from 0.7 to 2.5). The extra-column dispersions caused

Frédéric Lelièvre; Chao Yan; Richard N. Zare; P. Gareil

1996-01-01

382

TiO 2-NF-membranes on capillary supports  

Microsoft Academic Search

Starting from stress simulations suitable shapes of ceramic capillaries (outer diameter, OD; inner diameter, ID) were calculated. Capillaries were prepared by conventional extrusion down to an OD\\/ID 1.1 mm\\/0.7 mm. Capillaries with an 2.9 mm\\/1.9 mm were selected as the most favorite shape. A special coating technique was developed to prepare NF-membranes inside these types of capillaries. Single capillaries were

I. Voigt; G. Fischer; P. Puhlfürß; M. Schleifenheimer; M. Stahn

2003-01-01

383

Capillary pressure experiments under simulated reservoir conditions  

NASA Astrophysics Data System (ADS)

The contribution of residual trapping to a long-term storage of CO2 in saline aquifers mainly depends on the drainage capillary pressure of a reservoir and the hysteresis of the drainage and imbibition branches of the capillary pressure curve. However, the experimental database of capillary pressure measured at relevant pT conditions is still scarce. Here, we present an experimental set-up, which allows for the performance of capillary pressure experiments with a semi-permeable disk (porous plate) at simulated reservoir conditions. In the framework of the EU funded project CO2CARE, drainage and imbibition cycles are performed on Triassic sandstone samples. We use a temperature controlled oil pressure autoclave to apply a maximum confining pressure of 400 bar and a maximum working temperature of 150°C. The fluid displacement, and hence the sample saturation is controlled by a gear pump with a fine resolution of 0.01 ml. Additionally, the capillary pressure experiment is combined with measurements of elastic wave velocities as well as of the electrical resistivity. In this case, P and S wave velocities and the formation resistivity factor are determined as functions of the brine/ CO2 saturation. The experiment provides information about the efficiency of the capillary trapping of the sample and a calibration of the petrophysical properties on saturation.

Kummerow, J.; Spangenberg, E.

2012-04-01

384

Multiple capillary biochemical analyzer with barrier member  

DOEpatents

A multiple capillary biochemical analyzer for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal to noise ratio.

Dovichi, Norman J. (Edmonton, CA); Zhang, Jian Z. (Edmonton, CA)

1996-01-01

385

Multiple capillary biochemical analyzer with barrier member  

DOEpatents

A multiple capillary biochemical analyzer is disclosed for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal-to-noise ratio. 12 figs.

Dovichi, N.J.; Zhang, J.Z.

1996-10-22

386

High performance of cyclic olefin copolymer-based capillary electrophoretic chips.  

PubMed

This paper demonstrates a simple, one step, and low cost surface modification technique for producing cyclic olefin copolymer (COC) polymer-based microcapillary electrophoresis chips consisting highly hemocompatible microchannels by UV-photografting with N-vinylpyrrolidone (NVP) monomer. An optimal condition has been identified to achieve the best surface grafting process. It has been found that this surface treatment enables extremely high surface wettability, hemocompatibility, and bond strength to the microchannels. The surface grafting was confirmed by attenuated total reflection Fourier transform-infrared spectroscopic (ATR-FTIR) study. In vitro protein adsorption using fluorescent labeled bovine serum albumin (FITC-BSA) into the COC microchannel results indicates that the modified chips have excellent protein resistance ability because of the increase of surface hydrophilicity. Hence, the modified chips showed fast, reproducible and high efficient separations of proteins (up to 51,000 theoretical plates per meter). Moreover, this surface modification process show no loss in the optical transparency to the modified microchannel surfaces: an important requirement for real capillary electrophoresis since the fluorescent intensity is directly related to the amount of adsorbed protein on the surface. Therefore, we believe that this simple and promising route of surface modification could be very useful for developing high performance COC microfluidic devices for the separation of proteins, amino acids, and other biomolecules. PMID:23748936

Roy, Sunanda; Das, Tanya; Yue, C Y

2013-06-10

387

DNA Sequencing by Capillary Electrophoresis  

PubMed Central

Sequencing of human and other genomes has been at the center of interest in the biomedical field over the past several decades and is now leading toward an era of personalized medicine. During this time, DNA sequencing methods have evolved from the labor intensive slab gel electrophoresis, through automated multicapillary electrophoresis systems using fluorophore labeling with multispectral imaging, to the “next generation” technologies of cyclic array, hybridization based, nanopore and single molecule sequencing. Deciphering the genetic blueprint and follow-up confirmatory sequencing of Homo sapiens and other genomes was only possible by the advent of modern sequencing technologies that was a result of step by step advances with a contribution of academics, medical personnel and instrument companies. While next generation sequencing is moving ahead at break-neck speed, the multicapillary electrophoretic systems played an essential role in the sequencing of the Human Genome, the foundation of the field of genomics. In this prospective, we wish to overview the role of capillary electrophoresis in DNA sequencing based in part of several of our articles in this journal.

Karger, Barry L.; Guttman, Andras

2009-01-01

388

Nonlinear waves in capillary electrophoresis  

PubMed Central

Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration ‘shocks’. In this paper we consider a simplified model consisting of a single sample ion and a background electrolyte consisting of a single co-ion and a counterion in the absence of any processes that might change the ionization states of the constituents. If the ionic diffusivities are assumed to be the same for all constituents the concentration of sample ion is shown to obey a one dimensional advection diffusion equation with a concentration dependent advection velocity. If the analyte concentration is sufficiently low in a suitable non-dimensional sense, Burgers’ equation is recovered, and thus, the time dependent problem is exactly solvable with arbitrary initial conditions. In the case of small diffusivity either a leading edge or trailing edge shock is formed depending on the electrophoretic mobility of the sample ion relative to the background ions. Analytical formulas are presented for the shape, width and migration velocity of the sample peak and it is shown that axial dispersion at long times may be characterized by an effective diffusivity that is exactly calculated. These results are consistent with known observations from physical and numerical simulation experiments.

Ghosal, Sandip; Chen, Zhen

2011-01-01

389

OCT methods for capillary velocimetry  

PubMed Central

To date, two main categories of OCT techniques have been described for imaging hemodynamics: Doppler OCT and OCT angiography. Doppler OCT can measure axial velocity profiles and flow in arteries and veins, while OCT angiography can determine vascular morphology, tone, and presence or absence of red blood cell (RBC) perfusion. However, neither method can quantify RBC velocity in capillaries, where RBC flow is typically transverse to the probe beam and single-file. Here, we describe new methods that potentially address these limitations. Firstly, we describe a complex-valued OCT signal in terms of a static scattering component, dynamic scattering component, and noise. Secondly, we propose that the time scale of random fluctuations in the dynamic scattering component are related to red blood cell velocity. Analysis was performed along the slow axis of repeated B-scans to parallelize measurements. We correlate our purported velocity measurements against two-photon microscopy measurements of RBC velocity, and investigate changes during hypercapnia. Finally, we image the ischemic stroke penumbra during distal middle cerebral artery occlusion (dMCAO), where OCT velocimetry methods provide additional insight that is not afforded by either Doppler OCT or OCT angiography.

Srinivasan, Vivek J.; Radhakrishnan, Harsha; Lo, Eng H.; Mandeville, Emiri T.; Jiang, James Y.; Barry, Scott; Cable, Alex E.

2012-01-01

390

Four window differential capillary velocimetry.  

PubMed

A video red blood cell velocimeter was implemented with four photometric windows in such a fashion that the upstream and downstream signals are the difference between spatially separated window pairs. The performance of this system was compared with that of a conventional dual window photometric video velocimeter. Tests were made with artificial patterns of red blood cells that simulated long trains of contiguous cells, or large plasma gaps. It was found that the four window system produces a correlogram that is better suited for delay to maximum cross-correlation detection. Similarly, when the responses of the two methods were compared in terms of ability to detect changes of velocity, the time constant for a test step velocity change was found to be 1.2 +/- 0.7 sec for the four window system vs 2.3 +/- 0.6 sec for the two window system. It is concluded that this modification of the capillary red blood cell velocimetry methodology is better suited for detecting the spontaneous flow variations due to vasomotion. PMID:2144607

Intaglietta, M; Breit, G A; Tompkins, W R

1990-07-01

391

Biocompatibility and wettability of crystalline SiC and Si surfaces.  

PubMed

Crystalline silicon carbide (SiC) and silicon (Si) biocompatibility was evaluated by directly culturing three mammalian cell lines on these semiconducting substrates. Cell proliferation and adhesion quality were studied using MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays and fluorescent microscopy. The reported results show that SiC is indeed a more biocompatible substrate than Si. The surface wettability of SiC and Si samples was evaluated through static contact angle measurements, which provided interesting information regarding the influence of different cleaning procedures on the SiC surfaces. The cell proliferation data are discussed in light of the contact angle measurements results. This joint analysis leads to interesting conclusions that may help to uncover the main factors that define a semiconductor's biocompatibility. PMID:18003344

Coletti, C; Jaroszeski, M J; Pallaoro, A; Hoff, A M; Iannotta, S; Saddow, S E

2007-01-01

392

Wettability, Oil Recovery, and Interfacial Tension with an SDBS-Dodecane-Kaolin System.  

PubMed

The wettability of kaolin with SDBS (sodium dodecyl benzene sulfonate) aqueous solutions was measured by the Washburn equation expressed as contact angles. The contact angle changes for SDBS aqueous solutions on kaolin surface was studied. The interfacial tension between the SDBS solutions and n-dodecane was measured using both drop volume and spinning drop methods. Then the oil recovery of n-dodecane on the kaolin surface was tested. It was found that the minimum contact angle (the most hydrophilic condition) and the maximum oil recovery occurred near the critical micelle concentration (CMC) of SDBS while the interfacial tension between the SDBS solution and n-dodecane was far from ultra-low. Copyright 1999 Academic Press. PMID:10339376

Bi; Zhang; Xu; Qian; Yu

1999-06-15

393

Tuning the wettability of an aluminum surface via a chemically deposited fractal dendrite structure.  

PubMed

We have developed a straightforward method to tune the wettability of an aluminum substrate within a contact angle (CA) range from 2(°) to 170(°) by chemical deposition in CuCl2 solution and fluoroalkylsilane (FAS) modification. The CA of the as-deposited surface decreases with deposition time due to the growth of fractal copper dendrites, which enhance the surface roughness significantly. After subsequent modification with FAS, a superhydrophobic surface with CA 170(°) and sliding angle less than 5(°) has been obtained. With the increase of CA, the maximum spreading of water droplets is reduced. A bouncing behavior is observed for droplets impinging on the superhydrophobic substrate, suggesting its potential application as a self-cleaning surface. PMID:23793831

Zang, Duyang; Li, Feng; Geng, Xingguo; Lin, Kejun; Clegg, Paul S

2013-06-20

394

Gallium-based thermal interface material with high compliance and wettability  

NASA Astrophysics Data System (ADS)

This study reports a gallium-based thermal interface material (GBTIM) consisting of gallium oxides dispersed uniformly into the 99 % gallium metal. The wettability of GBTIM with other materials is disclosed and compared. The thermal conductivity of GBTIM measured by a computer-controlled Mathis TCi thermal analyzer is ˜13.07 W m-1 K-1 at room temperature, which is significantly higher than that of conventional thermal greases. An experimental facility is described to measure the thermal resistance across the GBTIM under steady-state conditions and the thermal interface resistance is measured as low as 2.6 mm2 kW-1 with a pressure of 0.05 MPa, which is an order lower than that of the best commercialized thermal greases. Further, the GBTIM is formed into a desired shape to enhance thermal transfer, such as semi-liquid paste or thermal pad, which can be cut into a required shape.

Gao, Yunxia; Liu, Jing

2012-06-01

395

Determining the Contribution of Epidermal Cell Shape to Petal Wettability Using Isogenic Antirrhinum Lines  

PubMed Central

The petal epidermis acts not only as a barrier to the outside world but also as a point of interaction between the flower and potential pollinators. The presence of conical petal epidermal cells has previously been shown to influence the attractiveness of the flower to pollinating insects. Using Antirrhinum isogenic lines differing only in the presence of a single epidermal structure, conical cells, we were able to investigate how the structure of the epidermis influences petal wettability by measuring the surface contact angle of water drops. Conical cells have a significant impact on how water is retained on the flower surface, which may have indirect consequences for pollinator behaviour. We discuss how the petal epidermis is a highly multifunctional one and how a battery of methods, including the use of isogenic lines, is required to untangle the impacts of specific epidermal properties in an ecological context.

Whitney, Heather M.; Poetes, Rosa; Steiner, Ullrich; Chittka, Lars; Glover, Beverley J.

2011-01-01

396

Importance of excipient wettability on tablet characteristics prepared by moisture activated dry granulation (MADG).  

PubMed

For moisture activated dry granulation (MADG), microcrystalline cellulose (MCC) or silicon dioxide is recommended for the moisture absorption stage. The aim of this study was to assess the suitability of alternative excipients as moisture absorbents with regard to the disintegration mechanism of resulting lactose based placebo formulations. Beside high and low moisture MCC grades, the additions of magnesium aluminometasilicate (MAMS), pregelatinized starch (S1500), crospovidone (Kollidon CL) and carmellose calcium (ECG 505) were evaluated. High shear granulation (HSG) was conducted as a reference process. The overall disintegration time of all tablets produced by MADG was significantly faster whereas hardness yield and mass-variability were equal or superior compared to the HSG process. Powder wettability of the different moisture absorbents was identified to be a key driver for rapid disintegration, whereas tablet porosity had only a minor influence on the target hardness of the tablets. PMID:23994013

Takasaki, Hiroshi; Yonemochi, Etsuo; Messerschmid, Roman; Ito, Masanori; Wada, Koichi; Terada, Katsuhide

2013-08-27

397

Fabrication of super-repellent cotton textiles with rapid reversible wettability switching of diverse liquids  

NASA Astrophysics Data System (ADS)

By in situ introducing polyaniline (PANI) and perfluorooctanoic acid (PFOA) to cotton fibers, normally hydrophilic and oleophilic cotton textile has easily turned superhydrophobic and highly oleophobic. This super-repellent cotton fabric exhibits a high contact angle (>150°) and low contact angle hysteresis, even with liquids possessing significantly low surface tension. The water or oil repellent property is ascribed to the combination of a dual-size surface roughness and low-surface-energy material. In particular, a reversible wettability switching of various low-surface-tension liquids on the PANI-fabric can be simultaneously observed, when it is doped with PFOA and de-doped with sodium hydroxide via a simple dipping method. This transition can be explained by the conversion of fluorine content and hydrophilic groups on the surface during the doping/dedoping process. Besides, this doping polymerization and dedoping process can slightly affect the mechanical strength of the cotton fabrics, even with harsh chemicals like acid and base.

Zhou, Xiaoyan; Zhang, Zhaozhu; Xu, Xianghui; Men, Xuehu; Zhu, Xiaotao

2013-07-01

398

Effect of airborne contaminants on the wettability of supported graphene and graphite  

NASA Astrophysics Data System (ADS)

It is generally accepted that supported graphene is hydrophobic and that its water contact angle is similar to that of graphite. Here, we show that the water contact angles of freshly prepared supported graphene and graphite surfaces increase when they are exposed to ambient air. By using infrared spectroscopy and X-ray photoelectron spectroscopy we demonstrate that airborne hydrocarbons adsorb on graphitic surfaces, and that a concurrent decrease in the water contact angle occurs when these contaminants are partially removed by both thermal annealing and controlled ultraviolet-O3 treatment. Our findings indicate that graphitic surfaces are more hydrophilic than previously believed, and suggest that previously reported data on the wettability of graphitic surfaces may have been affected by unintentional hydrocarbon contamination from ambient air.

Li, Zhiting; Wang, Yongjin; Kozbial, Andrew; Shenoy, Ganesh; Zhou, Feng; McGinley, Rebecca; Ireland, Patrick; Morganstein, Brittni; Kunkel, Alyssa; Surwade, Sumedh P.; Li, Lei; Liu, Haitao

2013-10-01

399

Improving endothelialization on 316L stainless steel through wettability controllable coating by sol-gel technology  

NASA Astrophysics Data System (ADS)

Rapid endothelialization by surface coverage is considered as a way to increase blood compatibility of the vascular stent and reduce smooth muscle cell (SMC) mediated restenosis. Coatings on 316L stainless steels with different wettabilities and similar topographies were obtained through sol-gel process by regulating the proportions of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES). Adhesion and proliferation of vascular endothelial cells (EC) and SMC on these substrates have been evaluated by cell numbers, cell morphology, and expression of cytoskeletal protein. Results showed that EC and SMC responded differently to the coated surfaces. Enhanced endothelialization of bare 316L was found at the moderately hydrophilic coating (contact angle 45.3°) which exhibited effective inhibition of SMC and negligible influence on EC. These results are expected to lay foundation for the solution of the vascular restenosis which was mainly derived from the hyperplasia of SMC.

Wang, Mingqi; Wang, Yao; Chen, Yijie; Gu, Hongchen

2013-03-01

400

Wettability behaviour of RTV silicone rubber coated on nanostructured aluminium surface  

NASA Astrophysics Data System (ADS)

A nanostructutered superhydrophobic surface was elaborated by applying an RTV silicone rubber coating on electrochemically processed aluminium substrates. Study of anodisation voltage on surface morphology showed that higher anodising voltage led to larger pore sizes. Scanning electron microscopy image analysis showed bird's nest and beehive structures formed on anodised surfaces at 50 V and 80 V. Water static contact angle on the treated surfaces reached up to 160° at room temperature. Study of superhydrophobic surfaces at super cooled temperature showed important delayed freezing time for RTV hydrophobic surfaces when compared to non-treated aluminium. However, lower wettability was observed when surface temperature went down from 20 °C to -10 °C. Also, it was found that the capacitance of superhydrophobic surfaces decreased with increasing anodising voltage.

Momen, Gelareh; Farzaneh, Masoud; Jafari, Reza

2011-05-01

401

Wettability and osteoblast cell response modulation through UV laser processing of nylon 6,6  

NASA Astrophysics Data System (ADS)

With an ageing population the demand for cheap, efficient implants is ever increasing. Laser surface treatment offers a unique means of varying biomimetic properties to determine generic parameters to predict cell responses. This paper details how a KrF excimer laser can be employed for both laser-induced patterning and whole area irradiative processing to modulate the wettability characteristics and osteoblast cell response following 24 h and 4 day incubation. Through white light interferometry (WLI) it was found that the surface roughness had considerably increased by up to 1.5 ?m for the laser-induced patterned samples and remained somewhat constant at around 0.1 ?m for the whole area irradiative processed samples. A sessile drop device determined that the wettability characteristics differed between the surface treatments. For the patterned samples the contact angle, ?, increased by up to 25° which can be attributed to a mixed-state wetting regime. For the whole area irradiative processed samples ? decreased owed to an increase in polar component, ?P. For all samples ? was a decreasing function of the surface energy. The laser whole area irradiative processed samples gave rise to a distinct correlative trend between the cell response, ? and ?P. However, no strong relationship was determined for the laser-induced patterned samples due to the mixed-state wetting regime. As a result, owed to the relationships and evidence of cell differentiation one can deduce that laser whole area irradiative processing is an attractive technology for employment within regenerative medicine to meet the demands of an ageing population.

Waugh, D. G.; Lawrence, J.

2011-08-01

402

Wettability in reactive Sn-base alloy/Ni-base metallic glass systems  

NASA Astrophysics Data System (ADS)

Fluxless wetting of a Ni-base metallic glass alloy with a nominal composition of Ni-7Cr-3.2B-4.5Si-3Fe (wt.%) by several Sn-base solders was investigated using a dispensed sessile drop method in a high vacuum at 523 K, and their interfacial microstructures were characterized. The results show that the wettability was in the sequence of Sn-51 wt.% In > Sn-37 wt.% Pb > Sn-57 wt.% Bi > Sn-0.7 wt.% Cu > Sn-3.0 wt.% Ag-0.5 wt.% Cu > pure Sn. The interface consisted of two distinct layers with the upper being the reaction layer and the lower the Sn-diffusion layer. For the Sn-0.7 wt.% Cu, Sn-3.0 wt.% Ag-0.5 wt.% Cu and Sn-51 wt.% In solders, the primary reaction products were (Cu,Ni)6Sn5, (Ni,Cu)3Sn4 and Ni3(Sn,In)4, respectively, while for the other solders, they were Ni3Sn4. The thickness of the reaction layer in the central area varied in the order of Sn-51 wt.% In > pure Sn > Sn-3.0 wt.% Ag-0.5 wt.% Cu ? Sn-0.7 wt.% Cu > Sn-57 wt.% Bi > Sn-37 wt.% Pb, which is likely related to the concentration and diffusion rate of Sn. Moreover, the interfacial reaction facilitated the crystallization of the amorphous Ni-base substrates adjacent to the reaction layer and the crystallization in turn promoted the diffusion of Sn toward the substrate. The mechanisms for the different wettability of these solders with the Ni-base amorphous alloy were discussed, and finally suitable solders were recommended for the joining of this amorphous material

Zhang, Lin-Yang; Shen, Ping; Qi, Yan; Jiang, Qi-Chuan

2013-07-01

403

Reconstruction of Berea sandstone and pore-scale modelling of wettability effects  

Microsoft Academic Search

We present an integrated procedure for estimating permeability, conductivity, capillary pressure, and relative permeability of porous media. Although the method is general, we demonstrate its power and versatility on samples of Berea sandstone. The method utilizes petrographical information obtained from 2D thin sections to reconstruct 3D porous media. The permeability and conductivity are determined by solving numerically the local equations

Pål-Eric Øren; Stig Bakke

2003-01-01

404

Modeling the velocity field of the electroosmotic flow in charged capillaries and in capillary columns packed with charged particles: interstitial and intraparticle velocities in capillary electrochromatography systems  

Microsoft Academic Search

Mass transfer systems based on electrokinetic phenomena (i.e., capillary electrochromatography (CEC)) have shown practical potential in becoming powerful separation methods for the biotechnology and pharmaceutical industries. A mathematical model has been constructed and solved to describe quantitatively the profiles of the electrostatic potential, pressure, and velocity of the electroosmotic flow (EOF) in charged cylindrical capillaries and in capillary columns packed

A. I. Liapis; B. A. Grimes

2000-01-01

405

Capillary liquid chromatography using laser-based and mass spectrometric detection. [Capillary zone electrophoresis (CZE); micellar electrokinetic capillary kchromatography (MECC)  

SciTech Connect

In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

Sepaniak, M.J.; Cook, K.D.

1992-01-01

406

Characterization of Sorbed Oil Components on Clays and Quartz Grains in Oil Sand. A Contribution to the Wettability of Reservoir Rocks in Petroleum Deposits.  

National Technical Information Service (NTIS)

The wettability of an oil reservoir strongly influences the recovery rate during primary production and the feasibility of Enhanced Oil Recovery. In order to achieve an insight into the chemical nature of the oil components sorbed onto mineral surfaces, u...

A. Fendel

1989-01-01

407

Switchable capillary bridges in sphere packings  

NASA Astrophysics Data System (ADS)

If one adds a small amount of water to a heap of sand, it becomes paste-like since the grains get interconnected by capillary bridges. Due to this effect, we can easily sculpture wet sand (e.g., building a sand castle), whereas a heap of dry grains ripples away and cannot sustain any shape. In the present work, we use a non-Brownian suspension of glass spheres immersed in a binary liquid mixture. The suspending water-lutidine mixture exhibits a well studied lower critical point slightly above ambient temperature. Hence, the mixture starts to phase separate upon heating. Since the water-rich phase wets the hydrophilic glass spheres, capillary bridges are formed between adjacent particles. If the system is cooled below the demixing temperature, the bridges disappear within a few seconds by intermolecular diffusion. Thus, this systems offers the opportunity to switch the capillary bridges on and off by altering the temperature. In this presentation, we will show the temperature-induced formation of capillary bridges using confocal and bright light microscopy [1]. Furthermore, we will discuss the effect of capillary bridges on random sphere packings using a fluidized bed setup. [4pt] [1] C. G"ogelein, M. Brinkmann, M. Schr"oter, and S. Herminghaus, Langmuir 26 (2010) 22, 17184.

Gögelein, Christoph; Brinkmann, Martin; Schröter, Matthias; Herminghaus, Stephan

2011-03-01

408

Effect of nano-TiO2 addition on wettability and interfacial reactions of Sn0.7Cu composite solder\\/Cu solder joints  

Microsoft Academic Search

The influences of intermixing nano-TiO2 particles on the wettability and interfacial reaction of Sn0.7Cu composite solder with Cu substrate were investigated. The wettability of the Sn0.7Cu composite solder alloy was measured by the sessile-drop method under a 10-3 Torr vacuum solder at 250 °C up to 1800 s. Scanning electron microscopy (SEM) was used to quantify the interfacial microstructure for

L. C. Tsao; B. C. Wang; C. W. Chang; M. W. Wu

2010-01-01

409

Pore-Scale Monitoring of Wettability Alteration by Silica Nanoparticles During Polymer Flooding to Heavy Oil in a Five-Spot Glass Micromodel  

Microsoft Academic Search

It is well known that the oil recovery is affected by wettability of porous medium; however, the role of nanoparticles on\\u000a wettability alteration of medium surfaces has remained a topic of debate in the literature. Furthermore, there is a little\\u000a information of the way dispersed silica nanoparticles affect the oil recovery efficiency during polymer flooding, especially,\\u000a when heavy oil is

Ali Maghzi; Ali Mohebbi; Riyaz Kharrat; Mohammad Hossein Ghazanfari

2011-01-01

410

Capillary force repels coffee-ring effect.  

PubMed

When a coffee drop dries on a solid surface, it leaves a ringlike deposit along the edge and this is known as the "coffee-ring effect." We find a different motion of particles repelling the coffee-ring effect in drying droplets; the motion of particles that is initially toward the edge by the coffee-ring effect is reversed toward the center by a capillary force. The reversal takes place when the capillary force prevails over the outward coffee-ring flow. We discuss the geometric constraints for the capillary force and the reverse motion. Our findings of reversal phenomena would be important in many scenarios of drying colloidal fluids. PMID:20866682

Weon, Byung Mook; Je, Jung Ho

2010-07-26

411

Tryptic digest mapping by gradient capillary electrochromatography.  

PubMed

A high performance liquid chromatography (HPLC) system complemented with T-split, capillary detection cell and a high voltage power supply was used for peptide mapping by gradient electrochromatography and nanoliquid chromatography (nano-LC). With capillary columns of 100 microm ID, 6 cm packed with octadecylated 1.5 microm silica particles, the typical analysis time was approximately 10-15 min. The resolution of a tryptic digest of cytochrome c obtained by electrochromatography at 100 kV/m was superior compared to the analysis by nano-LC. Bubble formation caused by Joule heating at currents up to 100 microA was successfully suppressed by using a resistor capillary of 25 microm ID connected to the outlet of the packed column. PMID:10065962

Behnke, B; Metzger, J W

1999-01-01

412

Characterization of bovine collagens using capillary electrophoresis.  

PubMed

A capillary electrophoresis method was developed and characterized for analyzing the spectrum of collagen subspecies in collagen preparations. The Bio-Rad CE-SDS protein kit was used for the dynamic sieving separation of collagen subspecies in this CE method (DSCE). The optimized method utilized a 36 cm (or 24 cm) x 50 microm uncoated capillary, electrophoretic injection at 10 kV for 10 s, a run voltage of 15 kV, a capillary temperature of 20 degrees C, and UV detection at 220 nm. A preliminary validation of the method was performed. The assay had good repeatability (RSDs for peaks were 15%), and responses were linear for assay solutions with collagen concentrations from 0.125 to 1.25 mg/ml. The DSCE electropherogram of bovine skin collagen provided a profile of subspecies similar in number and relative abundance to that generated by scanning of Coomassie-stained SDS-PAGE gels. PMID:10857565

Chang, P; Kuan, S; Eberlein, G; Burke, D; Jones, R

2000-07-01

413

Application of capillary electrophoresis in glycoprotein analysis.  

PubMed

Capillary electrophoresis (CE) is a versatile analytical method used to characterize glycoproteins. We have used several modes of CE separation such as CE-SDS gel, imaged capillary isoelectric focusing (icIEF), and capillary zone electrophoresis (CZE) to study therapeutic glycoprotein products. CE-SDS gel is applied to characterize the glycan occupancy and number of glycosylation sites, and icIEF is used to study the charge heterogeneities due to sialic acids in glycoproteins. To further characterize the glycoprotein, removal of N-linked glycans is necessary and a CZE technique is employed to analyze each glycan moiety. Examples from a monoclonal antibody, erythropoietin, and granulocyte colony-stimulating factor are presented here to demonstrate the utility of these CE modes. The details of sample preparation and separation conditions for each CE mode are described in this chapter. PMID:23475720

Rustandi, Richard R; Anderson, Carrie; Hamm, Melissa

2013-01-01

414

Capillary breakup of discontinuously rate thickening suspensions.  

PubMed

Using discontinuously rate thickening suspensions (DRTS) as a model system, we show that beads-on-a-string morphologies can arise as a result of external viscous drag acting during capillary-driven breakup of a non-Newtonian fluid. To minimize the perturbative effect of gravity, we developed a new experimental test platform in which the filament is supported in a horizontal position at the surface of an immiscible oil bath. We show that the evolution of thin DRTS filaments during the capillary thinning process is well described by a set of one-dimensional slender filament equations. The strongly rate-dependent rheology of the test fluid and the aspect ratio of the filament couple to control the thinning dynamics and lead to a simple criterion describing the localized arrest of the capillary thinning process and the subsequent formation of complex, high aspect ratio beads-on-a-string structures. PMID:23909338

Zimoch, Pawel J; McKinley, Gareth H; Hosoi, A E

2013-07-19

415

Prediction of tilted capillary barrier performance  

SciTech Connect

Capillary barriers, consisting of tilted fine-over-coarse layers under unsaturated conditions, have been suggested as landfill covers to divert water infiltration away from sensitive underground regions, especially for arid and semi-arid regions. The Hydrological Evaluation of Landfill Performance (HELP) computer code is an evaluation tool for landfill covers used by designers and regulators. HELP is a quasi-two-dimensional model that predicts moisture movement into and through the underground soil and waste layers. Processes modeled within HELP include precipitation, runoff, evapotranspiration, unsaturated vertical drainage, saturated lateral drainage, and leakage through liners. Unfortunately, multidimensional unsaturated flow phenomena that are necessary for evaluating tilted capillary barriers are not included in HELP. Differences between the predictions of the HELP and those from a multidimensional unsaturated flow code are presented to assess the two different approaches. Comparisons are presented for the landfill covers including capillary barrier configurations at the Alternative Landfill Cover Demonstration (ALCD) being conducted at Sandia.

Webb, S.W.; McCord, J.T.; Dwyer, S.F.

1997-04-01

416

Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic glasses  

NASA Astrophysics Data System (ADS)

The corrosion properties of two Zr-based bulk metallic glass, Zr41Ti14Cu12Ni10Be23 (LM1) and Zr44Ti11Cu10Ni10Be25 (LM1b) were investigated by electrochemical measurements in simulated body fluid with pH value 7.4. With much lower current density and higher impedance values, as well as higher pitting potential, LM1b showed superior corrosion resistance to LM1. Under identical sample preparation and testing conditions, the difference in corrosion performance is found to relate closely to their surface wettability difference, as contact angle tests showed that LM1b is more hydrophobic than LM1. The excess free volume was measured and found having a close correlation with the wettability or the surface energy.

Wang, Y. B.; Li, H. F.; Zheng, Y. F.; Wei, S. C.; Li, M.

2010-06-01

417

Solvent-responsive wettability of self-assembled monolayers of dithiooctanoic Acid derivatives bearing n,n-disubstituted amide groups.  

PubMed

We have designed and synthesized two dithiooctanoic acid derivatives bearing N,N-disubstituted amide groups and used them to fabricate self-assembled monolayers (SAMs) on gold surface. These films showed a reversible changes in wettability, one of which was indicated by surface contact angle switching between 40° and 59° upon alternating treatment with ethanol and cyclohexane. NMR experimental results of a model molecule suggest that the solvent-responsive wettability of the SAMs could be related with the changes in the relative populations of two stereoisomers of amide. The solvent responsivity of SAMs fabricated from other two amides was also studied, and the results confirmed that N,N-disubstitution was essential for an amide-containing SAM to have stimuli responsivity. Thus, introduction of a functional group exhibiting controlled isomerization of conformation could be an effective strategy for designing new stimuli-responsive materials. PMID:24079368

Liu, Fangming; Pang, Juan; Wang, Chunyu; Wang, Liyan

2013-10-11

418

Effect of veneer side wettability on bonding quality of Eucalyptus globulus plywoods prepared using a tannin-phenol-formaldehyde adhesive.  

PubMed

The influence of rotary peeling on the different behaviour of tight and loose sides of Eucalyptus globulus veneers has been studied. The presence of lathe checks on the loose sides favours wettability, the contact angle decreasing more rapidly on these sides than on tight sides. Additionally, pine bark tannins improved wettability due to their surfactant character. Bonding quality tests carried out on plywoods prepared using a tannin-phenol-formaldehyde adhesive showed that fracture almost invariably occurred in a glue line with at least one loose side, where wood failure appeared. This behaviour, confirmed by analysing the glue lines by means of fluorescence microscopy, was due to the large surface alterations of the loose sides which reduced mechanical strength but allowed greater penetration of the adhesive giving rise to high wood failure. PMID:12507878

Vázquez, G; González-Alvarez, J; López-Suevos, F; Antorrena, G

2003-05-01

419

Integrins-FAK-Rho GTPases pathway in endothelial cells sense and response to surface wettability of plasma nanocoatings.  

PubMed

Vascular endothelial cell (EC) adhesion and migration are essential processes in re-endothelialization of implanted biomaterials, which are affected by surface properties of implanted materials such as surface wettability. Our previous study demonstrated that, as model substrates, EC adhesion/migration showed an opposite behavior on the hydrophobic and hydrophilic surfaces of plasma SiOx:H nanocoatings. Extending our previous works, the expression and distribution of crucial proteins in integrins-FAK-Rho GTPases signaling pathways were examined, respectively. The results showed that a hydrophilic surface could enhance the expression of focal adhesion protein associated with cell adhesion; however, the hydrophobic surface could improve the expression of Rho GTPases associated with cell migration and phosphorylation level of FAK, revealing the potential reason of surface wettability mediating different cells' adhesion/migration behaviors. These findings reveal the relationship and molecular mechanism of endothelial cell adhesion/migration, which was expected to guide the surface modification of implants for accelerating endothelialization. PMID:23676504

Shen, Yang; Ma, Yunlong; Gao, Min; Lai, Yi; Wang, Guixue; Yu, Qingsong; Cui, Fu-zhai; Liu, Xiaoheng

2013-05-15

420

HPTLC Plate Blotting for Liquid Microjunction Surface Sampling Probe Mass Spectrometric Analysis of Analytes Separated on a Wettable Phase Plate  

SciTech Connect

A blotting method that transfers analytes separated on wettable HPTLC plates to a hydrophobic reversed-phase C8 HPLTC plate suitable for analysis with a liquid microjunction surface sampling probe electrospray ionization mass spectrometry system was described and demonstrated. The simple blotting procedure transfers the analyte from the wettable plate to the topmost surface of a rigidly backed, easy-to-mount hydrophobic substrate that already has been proven viable for analysis by this sampling probe/mass spectrometry system. The utility of the approach was demonstrated by the analysis of a four-component peptide mixture originally separated on a ProteoChrom HPTLC cellulose sheet and then blotted to the reversed phase HPTLC plate.

Walworth, Matthew J [ORNL; Stankovich, Joseph J [ORNL; Van Berkel, Gary J [ORNL; Schulz, Michael [Merck Research Laboratories; Minarik, susanne [Merck Research Laboratories

2012-01-01

421

Interfacial Reaction and Wettability of 72Ag-28Cu Braze on CP-Ti Substrate Using Infrared Heating  

NASA Astrophysics Data System (ADS)

Reactive wetting by infrared heating of a BAg-8 braze on a CP-Ti substrate is achieved at 1073 K (800 °C) for 300 seconds. Increasing the test temperature from 1073 K to 1123 K (800 °C to 850 °C) results in great improvement of the wettability on the CP-Ti substrate due to the lower melt viscosity at higher test temperature and the alloying effect of Cu into the CP-Ti substrate to form the interfacial eutectoid layer.

Shiue, R. K.; Wu, S. K.; Chen, F. Y.; Yang, T. E.

2012-06-01

422

Germination of Phyllosticta ampelicidaPycnidiospores: Prerequisite of Adhesion to the Substratum and the Relationship of Substratum Wettability  

Microsoft Academic Search

Pycnidiospores ofPhyllosticta ampelicida,the causal agent of black rot of grape, were found to germinate only on substrata on which they were firmly attached. Such surfaces were poorly wettable and had advancing contact angles (?a) formed by a water drop of >80°, e.g., grape leaf, polystyrene, Teflon, polycarbonate, collodion, and glass treated with the silanesn-octadecyltrichlorosilane, dimethyldichlorosilane, or diphenyldichlorosilane. When pycnidiospores were

KerChung Kuo; H. C. Hoch

1996-01-01

423

Properties of ternary Sn-Ag-Bi solder alloys: Part II—Wettability and mechanical properties analyses  

Microsoft Academic Search

Bismuth additions of 1% to 10% were made to the 96.5Sn-3.5Ag (wt.%) alloy in a study to develop a Sn-Ag-Bi ternary composition.\\u000a Thermal properties and microstructural analyses of selected alloy compositions were reported in Part I. Wettability and mechanical\\u000a properties are described in this paper. Contact angle measurements demonstrated that Bi additions improved wetting\\/spreading\\u000a performance on Cu; a minimum contact

P. T. Vianco; J. A. Rejent

1999-01-01

424

Microbial biofilm growth versus tissue integration on biomaterials with different wettabilities and a polymer-brush coating  

Microsoft Academic Search

Biomaterials-associated infections (BAI) constitute a major clinical problem and often necessitate implant replacement. In this study, the race for the surface between Staphylococcus epidermidis ATCC 35983 and U2OS osteosarcoma cells is studied on biomaterials with different wettabilities and on a polymer-brush coating. S. epidermidis was deposited on the different surfaces in a parallel plate flow chamber and then U2OS cells

Guruprakash Subbiahdoss; Dirk W. Grijpma; Mei van der Henny C; Henk J. Busscher; Roel Kuijer

2010-01-01

425

The Surface Wettability and Adhesion of Poly(Ester Urethane)s and Poly(Ether Urethane)s  

Microsoft Academic Search

In this study the wetting characteristics of untreated and plasma-treated polyurethane thin films were investigated. The degree of wettability was investigated by measuring the contact angle formed between a liquid drop and the solid surface. The work of adhesion, interfacial free energy, spreading coefficient, and Girifalco–Good's interaction parameter changed significantly for plasma-treated polyurethane films. Both complete and partial wetting were

Mihaela Homocianu; Doina Macocinschi; Maria Butnaru

2011-01-01

426

Wettability and surface charge of Si 3N 4–bioglass composites in contact with simulated physiological liquids  

Microsoft Academic Search

Wettability and surface charge studies were performed on a novel Si3N4–30wt% bioglass biocomposite. Contact angle and surface tension variation with time were determined at 25°C, respectively, by the sessile and pendant drop techniques, for distinct testing liquids: water, diiodomethane, simulated body fluid (SBF) and bovine serum albumin (BSA) dissolved in SBF solution. This biocomposite revealed a hydrophilic character (?=26.6±2.0°) and

M Amaral; M. A Lopes; J. D Santos; R. F Silva

2002-01-01

427

On the effects of using CO 2 and F 2 lasers to modify the wettability of a polymeric biomaterial  

Microsoft Academic Search

Enhancement of the surface properties of a material by means of laser radiation has been amply demonstrated previously. In this work a comparative study for the surface modification of nylon 6,6 has been conducted in order to vary the wettability characteristics using CO2 and excimer lasers. This was done by producing 50?m spaced (with depths between 1 and 10?m) trench-like

D. G. Waugh; J. Lawrence; C. D. Walton; R. B. Zakaria

2010-01-01

428

Electrospun Poly(?-Benzyl-L-Glutamate) and Its Alkali-Treated Meshes: Their Water Wettability and Cell-Adhesion Potential  

Microsoft Academic Search

The aim of this study was (1) to fabricate non-woven meshes from a biodegradable polymer, poly(?-benzylL-glutamate), by electrospinning and subsequent hydrolysis of the ester bond on the polymer side-chain in an aqueous solution of NaOH, creating surface carboxyl groups on the fibers, and (2) to determine the effect of hydrolysis time on water wettability and cellular behaviors, in order to

Yoshihiro Hakamada; Nao Ohgushi; Nozomi Fujimura-Kondo; Takehisa Matsuda

2012-01-01

429

The effect of acquired salivary pellicle on the surface free energy and wettability of different denture base materials  

Microsoft Academic Search

Objective: The objective of the present study was to evaluate the effect of salivary coating on the wettability and surface free energy of different denture base materials.Methods: Five acrylic resin and two metallic denture base materials were investigated. Ten specimens of each material (20×15×1.5mm) were fabricated and a standardized method was used for polishing the test specimens. Whole unstimulated saliva

C Sipahi; N Anil; E Bayramli

2001-01-01

430

Effect of various treatment and glazing (coating) techniques on the roughness and wettability of ceramic dental restorative surfaces.  

PubMed

Surface treatment procedures such as grinding and polishing are needed to provide the ceramic dental restorative materials with proper fitting and occlusion. The treated surfaces are customarily glazed to improve the strength and smoothness. Though smoothness and wetting of the dental surfaces are important to minimize bacterial plaque retention, influence of the surface treatment and glazing procedures on the final surface roughness and its correlation to wettability are overlooked. In this work, effect of various treatment (diamond fraising, stoning, sanding and aluminum oxide and rubber polishing) and glazing (auto and overglazing) techniques on the final roughness and the resulting wettability of dental ceramic surfaces were investigated using scanning electron microscopy (SEM) observations and atomic force microscopy (AFM) scans, 75 scans per sample. The surfaces were characterized and assigned an average roughness measure, R(a). The wettability of the same surfaces was evaluated using micro-contact angle measurements (25 micro-bubbles placed on a grid on each surface) to correlate the final surface roughness and wettability. The results show that overglazing prevails over surface irregularities from different treatment procedures and provides homegeneously smooth surfaces with mean R(a)<10 nm. It also produces uniformly wetted surfaces with low contact angles around 20 degrees . The autoglazed surfaces are less smooth (mean R(a) around 50 nm) and displays sporadic topographic irregularities. They display larger and less uniform contact angles ranging between 35 degrees and 50 degrees . The results suggest that overglazing should be preferred after surface treatment to obtain a smooth and well-wetted dental ceramic surface. PMID:17097279

Aksoy, G; Polat, H; Polat, M; Coskun, G

2006-09-27

431

Electrochemical wettability control on conductive TiO2 nanotube surfaces modified with a ferrocene redox system  

Microsoft Academic Search

This work reports on an electrochemical system which allows the control of surface wettability properties by voltage induced changes in contact angle (?) of ?? ? 50°. For this we used conductive TiO2 nanotubular layers that were modified with ferrocene coupled to the TiO2 surface via triethoxysilane. To enhance the hydrophobic character of the nanotubular TiO2 surface, also mixed organic

Felix Schmidt-Stein; Jan-Frederik Gnichwitz; Jarno Salonen; Robert Hahn; Andreas Hirsch; Patrik Schmuki

2009-01-01

432

POLYSILOXANE DEACTIVATED FUSED SILICA CAPILLARIES CONTAINING IMMOBILIZED STATIONARY PHASES  

EPA Science Inventory

This article describes a method of preparing immobilized stationary phases which has arisen from the author's work on polysiloxane deactivation of fused silica capillaries. Although acid treatment is often omitted with fused silica capillaries, there are good reasons for hydrothe...

433

Effect of Surface Wettability on Nonlinear Flow in a Rough-Walled Fracture  

NASA Astrophysics Data System (ADS)

The understanding of flow behavior in rock fractures is essential to the analysis of water flow, solute transport and DNAPL migration and remediation in rock fractures. DNAPL migration and remediation in rock fractures has been an emerging issue due to its serious contamination problem and the difficulty in dealing with DNAPL trapped in rock fractures. It has been reported that while DNAPL migrates through rock fractures, DNAPL may be trapped on rock surfaces due to variable apertures and dead-end fractures, and may also change the surface wettability of rock fractures from hydrophilic to hydrophobic. In this study, the effect of surface wettability on water flow in rock fractures has been investigated. A glass replica of a real rough-walled fracture was made, and the fracture surface was brushed with corn oil to make the fracture surface hydrophobic. The corn oil was wiped off with tissues many times, to eliminate the oil remnants on the surface. Flow tests were conducted on the oil-wet fracture surface. Then, the surface was completely washed out with the cleaning agents to make the fracture surface hydrophilic, which was confirmed through contact angle measurements. Flow tests were repeated for the water-wet fracture surface. Flow tests were also carried out for a parallel glass plate fracture over the same water- and oil-wet surface conditions as in the rough fracture. In the parallel plate fracture, the hydraulic aperture from the oil-wet surface was only two percent higher that that of the water-wet surface, which indicated that the initial aperture of the fracture might not decrease by the corn-oil coating. Both oil- and water-wet surfaces of the parallel plate showed a linear flow regime, up to Reynolds number of 400. In the case of the rough fracture, the hydraulic aperture of the oil-wet fracture surface was smaller than that of the water-wet fracture surface. For the water-wet fracture surface, the non-linear flow started at Reynolds number less than 30, but in case of the oil-wet fracture surface, the non-linear flow did not begin up to Reynolds number of 50. The hydrophobic surface of the rough-walled fracture, which is formed during the migration of NAPL through rock fractures, may cause the non-linear flow to begin at a higher Reynolds number, compared with the case of the water-wet fracture surface.

Lee, H.; Yeo, I.; Park, J.; Lee, K.

2005-12-01

434

WETTABILITY AND IMBIBITION: MICROSCOPIC DISTRIBUTION OF WETTING AND ITS CONSEQUENCES AT THE CORE AND FIELD SCALES  

SciTech Connect

The questions of reservoir wettability have been approached in this project from three directions. First, we have studied the properties of crude oils that contribute to wetting alteration in a reservoir. A database of more than 150 different crude oil samples has been established to facilitate examination of the relationships between crude oil chemical and physical properties and their influence on reservoir wetting. In the course of this work an improved SARA analysis technique was developed and major advances were made in understanding asphaltene stability including development of a thermodynamic Asphaltene Solubility Model (ASM) and empirical methods for predicting the onset of instability. The CO-Wet database is a resource that will be used to guide wettability research in the future. The second approach is to study crude oil/brine/rock interactions on smooth surfaces. Contact angle measurements were made under controlled conditions on mica surfaces that had been exposed to many of the oils in the CO-Wet database. With this wealth of data, statistical tests can now be used to examine the relationships between crude oil properties and the tendencies of those oils to alter wetting. Traditionally, contact angles have been used as the primary wetting assessment tool on smooth surfaces. A new technique has been developed using an atomic forces microscope that adds a new dimension to the ability to characterize oil-treated surfaces. Ultimately we aim to understand wetting in porous media, the focus of the third approach taken in this project. Using oils from the CO-Wet database, experimental advances have been made in scaling the rate of imbibition, a sensitive measure of core wetting. Application of the scaling group to mixed-wet systems has been demonstrated for a range of core conditions. Investigations of imbibition in gas/liquid systems provided the motivation for theoretical advances as well. As a result of this project we have many new tools for studying wetting at microscopic and macroscopic scales and a library of well-characterized fluids for use in studies of crude oil/brine/rock interactions.

Jill S. Buckley; Norman R. Morrow; Chris Palmer; Purnendu K. Dasgupta

2003-02-01

435

Micro-nano hybrid structures with manipulated wettability using a two-step silicon etching on a large area  

PubMed Central

Nanoscale surface manipulation technique to control the surface roughness and the wettability is a challenging field for performance enhancement in boiling heat transfer. In this study, micro-nano hybrid structures (MNHS) with hierarchical geometries that lead to maximizing of surface area, roughness, and wettability are developed for the boiling applications. MNHS structures consist of micropillars or microcavities along with nanowires having the length to diameter ratio of about 100:1. MNHS is fabricated by a two-step silicon etching process, which are dry etching for micropattern and electroless silicon wet etching for nanowire synthesis. The fabrication process is readily capable of producing MNHS covering a wafer-scale area. By controlling the removal of polymeric passivation layers deposited during silicon dry etching (Bosch process), we can control the geometries for the hierarchical structure with or without the thin hydrophobic barriers that affect surface wettability. MNHS without sidewalls exhibit superhydrophilic behavior with a contact angle under 10°, whereas those with sidewalls preserved by the passivation layer display more hydrophobic characteristics with a contact angle near 60°.

2011-01-01

436

Superhydrophobic TiO2-Polymer Nanocomposite Surface with UV-Induced Reversible Wettability and Self-Cleaning Properties.  

PubMed

Multifunctional superhydrophobic nanocomposite surfaces based on photocatalytic materials, such as fluorosilane modified TiO2, have generated significant research interest. However, there are two challenges to forming such multifunctional surfaces with stable superhydrophobic properties: the photocatalytic oxidation of the hydrophobic functional groups, which leads to the permanent loss of superhydrophobicity, as well as the photoinduced reversible hydrolysis of the catalytic particle surface. Herein, we report a simple and inexpensive template lamination method to fabricate multifunctional TiO2-high-density polyethylene (HDPE) nanocomposite surfaces exhibiting superhydrophobicity, UV-induced reversible wettability, and self-cleaning properties. The laminated surface possesses a hierarchical roughness spanning the micro- to nanoscale range. This was achieved by using a wire mesh template to emboss the HDPE surface creating an array of polymeric posts while partially embedding untreated TiO2 nanoparticles selectively into the top surface of these features. The surface exhibits excellent superhydrophobic properties immediately after lamination without any chemical surface modification to the TiO2 nanoparticles. Exposure to UV light causes the surface to become hydrophilic. This change in wettability can be reversed by heating the surface to restore superhydrophobicity. The effect of TiO2 nanoparticle surface coverage and chemical composition on the mechanism and magnitude of wettability changes was studied by EDX and XPS. In addition, the ability of the surface to shed impacting water droplets as well as the ability of such droplets to clean away particulate contaminants was demonstrated. PMID:23889192

Xu, Qian Feng; Liu, Yang; Lin, Fang-Ju; Mondal, Bikash; Lyons, Alan M

2013-09-06

437

Bioinspired Patterning with Extreme Wettability Contrast on TiO2 Nanotube Array Surface: A Versatile Platform for Biomedical Applications.  

PubMed

Binary wettability patterned surfaces with extremely high wetting contrasts can be found in nature on living creatures. They offer a versatile platform for microfluidic management. In this work, a facile approach to fabricating erasable and rewritable surface patterns with extreme wettability contrasts (superhydrophilic/superhydrophobic) on a TiO2 nanotube array (TNA) surface through self-assembly and photocatalytic lithography is reported. The multifunctional micropatterned superhydrophobic TNA surface can act as a 2D scaffold for site-selective cell immobilization and reversible protein absorption. Most importantly, such a high-contrast wettability template can be used to construct various well-defined 3D functional patterns, such as calcium phosphate, silver nanoparticles, drugs, and biomolecules in a highly selective manner. The 3D functional patterns would be a versatile platform in a wide range of applications, especial for biomedical devices (e.g., high-throughput molecular sensing, targeted antibacterials, and drug delivery). In a proof-of-concept study, the surface-enhanced Raman scattering and antibacterial performance of the fabricated 3D AgNP@TNA pattern, and the targeted drug delivery for site-specific and high-sensitivity cancer cell assays was investigated. PMID:23420792

Lai, Yuekun; Lin, Longxiang; Pan, Fei; Huang, Jianying; Song, Ran; Huang, Yongxia; Lin, Changjian; Fuchs, Harald; Chi, Lifeng

2013-02-18

438

Action Learning.  

ERIC Educational Resources Information Center

|These four papers were presented at a symposium on action learning moderated by Lex Dilworth at the 1996 conference of the Academy of Human Resource Development. "Developing an Infrastructure for Individual and Organizational Change: Transfer of Learning from an Action Reflection Learning (ARL) Program" (ARL Inquiry) reports findings from a study…

1996

439

Capillary pumping for a two phase heat transport system  

NASA Astrophysics Data System (ADS)

It is suggested that capillary pumped heat transport loops could successfully meet the established criteria for at least one of the thermal control components in a man-tended, low Earth orbit, microgravity environment. The design and physics of the capillary pump are introduced. Problem areas such as the condensing radiator, startup/shutdown, noncondensable gas, and preflight testing are identified. An analytical model of the thermal capillary pumping loop is outlined. Experimental work on capillary pumping is reviewed.

Buchlin, J.-M.; Tinari, P. D.

440

Measurement of RBC deformation and velocity in capillaries in vivo  

Microsoft Academic Search

Red blood cells (RBC) become deformed while flowing through capillaries. We captured images of blood flow in capillaries and of RBC in the rat mesentery using a high-speed camera at 2000 frames\\/s and then directly measured and estimated the deformation and velocity of RBC in a non-uniform capillary. The distribution of the capillary diameter was determined by image processing. We applied

Jae Hong Jeong; Yasusiko Sugii; Motomu Minamiyama; Koji Okamoto

2006-01-01

441

Spectrometer capillary vessel and method of making same  

DOEpatents

The present invention is an arrangement of a glass capillary tube for use in spectroscopy. In particular, the invention is a capillary arranged in a manner permitting a plurality or multiplicity of passes of a sample material through a spectroscopic measurement zone. In a preferred embodiment, the multi-pass capillary is insertable within a standard NMR sample tube. The present invention further includes a method of making the multi-pass capillary tube and an apparatus for spinning the tube.

Linehan, John C. (Richland, WA); Yonker, Clement R. (Kennewick, WA); Zemanian, Thomas S. (Richland, WA); Franz, James A. (Kennewick, WA)

1995-01-01

442

Capillary interactions between particles bound to interfaces, liquid films and biomembranes.  

PubMed

This article is devoted to an overview, comparison and discussion of recent results (both theoretical and experimental) about lateral capillary forces. They appear when the contact of particles or other bodies with a fluid phase boundary causes perturbations in the interfacial shape. The capillary interaction is due to the overlap of such perturbations which can appear around floating particles, vertical cylinders, particles confined in a liquid film, inclusions in the membranes of lipid vesicles or living cells, etc. In the case of floating particles the perturbations are due to the particle weight; in this case the force decreases with the sixth power of the particle size and becomes immaterial for particles smaller than approximately 10 microm. In all other cases the interfacial deformations are due to the particle wetting properties; the resulting 'immersion' capillary forces can be operative even between very small particles, like protein globules. In many cases such forces can be responsible for the experimentally observed two-dimensional particle aggregation and ordering. An analogy between capillary and electrostatic forces enables one to introduce 'capillary charges' of the attached particles, which characterize the magnitude of the interfacial deformation and could be both positive and negative. Moreover, the capillary interaction between particle and wall resembles the image force in electrostatics. When a particle is moving bound to an interface under the action of a capillary force, one can determine the surface drag coefficient and the surface viscosity supposedly the magnitude of the capillary force is known. Alternative (but equivalent) energy and force approaches can be used for the theoretical description of the lateral capillary interactions. Both approaches require the Laplace equation of capillarity to be solved and the meniscus profile around the particles to be determined. The energy approach accounts for contributions due to the increase of the meniscus area, gravitational energy and/or energy of wetting. The second approach is based on calculating the net force exerted on the particle, which can originate from the hydrostatic pressure, interfacial tension and bending moment. In the case of small perturbations, the superposition approximation can be used to derive an asymptotic formula for the capillary forces, which has been found to agree well with the experiment. Capillary interactions between particles bound to spherical interfaces are also considered taking into account the special geometry and restricted area of such phase boundaries. A similar approach can be applied to quantify the forces between inclusions (transmembrane proteins) in lipid membranes. The deformations in a lipid membrane, due to the inclusions, can be described theoretically in the framework of a mechanical model of the lipid bilayer, which accounts for its 'hybrid' rheology (neither elastic body nor fluid). In all considered cases the lateral capillary interaction originates from the overlap of interfacial deformations and is subject to a unified theoretical treatment, despite the fact that the characteristic particle size can vary from 1 cm down to 1 nm. PMID:10768480

Kralchevsky, P A; Nagayama, K

2000-03-31

443

DESIGN ANALYSES OF CAPILLARY BURST VALVES IN CENTRIFUGAL MICROFLUIDICS  

Microsoft Academic Search

This paper presents current research in analysis of passive microfluidic capillary burst valves. A capillary burst valve stops the liquid flow using a capillary pressure barrier that develops when the channel cross section expands abruptly. Valves of this type provide the capability of precise control on sample location in microfluidic device. Detailed numerical analyses of the valve behaviour is presented

Jun Zeng; Deb Banerjee; Manish Deshpande; John R. Gilbert

444

Flow injection analysis–capillary electrophoresis system with hydrodynamic injection  

Microsoft Academic Search

A flow injection analysis–capillary electrophoresis (FIA–CE) system with hydrodynamic injection has been developed. Sample is injected in an electrolyte carrier solution pumped continuously in the FIA part of the system. The interface, connecting the FIA and the CE system moieties, accommodates one end of the separation capillary and a platinum electrode. The other capillary end and the second platinum electrode

Petr Kuban; Reza Pirmohammadi; Bo Karlberg

1999-01-01

445

Microangiopathy in Chronic Venous Insufficiency: Quantitative Assessment by Capillary Microscopy  

Microsoft Academic Search

Background: patients with lipodermatosclerosis (LDS) due to chronic venous disease (CVD) of the lower limb show proliferation and convolution of their skin capillaries. There has been no previous attempt to quantify the severity of venous disease according to the extent of morphological change.Aim: to quantify capillary damage in patients with CVD using capillary microscopy.Method: 132 patients attending the vascular clinic

M. H. Howlader; P. D. Coleridge Smith

2003-01-01

446

Optimization of metallic X-ray capillary production  

Microsoft Academic Search

Among all of X-ray capillaries, those produced from metals attract special attention due to their specific advantages: less severe limitations on the value of the critical reflection angle, better control of the capillary shape, the maintenance of the straight main axis. The metallic, single bounce capillaries with gold and rhodium internal surfaces described in this paper are produced according to

R. Mroczka; P. Bartosik; Z. Sawlowicz; K. Skrzypiec; G. Falkenberg; J. Wojcik; G. ?ukoci?ski; A. Kuczumow

2008-01-01

447

Potentials of capillary gas chromatography in toxicology today  

Microsoft Academic Search

The usefulness, the applicability and the limitations of capillary gas chromatography in various types of toxicological analysis were discussed. Technical parameters of capillary gas chromatography, such as type of injector, type of column with regard to material, size, and stationary phase were assessed in view of the requirements of toxicological analysis. The main advantage of capillary gas chromatography, i.e. high

M. Bogusz; J. P. Franke; R. A. Zeeuw

1984-01-01

448

Nanostructures of small-molecule organic crystals on capillary wave surfaces with controllable capillary lengths.  

PubMed

We report on the nanostructures of organic small-molecule pentacene crystals that have been vapor-deposited onto the capillary wave surfaces of thin liquid films. The characteristic lateral length of the capillary wave surface or the capillary length can be controlled by changing the thickness of the liquid films and, thus, the van der Waals interaction with the substrate. We find that the morphology of the organic crystals gradually varies from fractals to compact islands as the liquid film thickness increases. The square of average distance between organic crystal grains was also found to be proportional to the liquid film thickness. We discuss the possibility that these effects are driven by capillary fluctuations at the air-liquid interface. PMID:23351069

Lee, Hyun Hwi; Ahn, Kwangseok; Kim, Doris Yangsoo; Yu, Chung-Jong; Lee, Dong Ryeol

2013-02-08

449