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1

Capillary flow solder wettability test  

SciTech Connect

A test procedure was developed to assess the capillary flow wettability of solders inside of a confined geometry. The test geometry was comprised of two parallel plates with a controlled gap of constant thickness (0.008 cm, 0.018 cm, 0.025 cm, and 0.038 cm). Capillary flow was assessed by: (1) the meniscus or capillary rise of the solder within the gap, (2) the extent of void formation in the gap, and (3) the time-dependence of the risen solder film. Tests were performed with the lead-free solders.

Vianco, P.T.; Rejent, J.A.

1996-01-01

2

Exploring Capillary Action  

NSDL National Science Digital Library

Students observe multiple examples of capillary action. First they observe the shape of a glass-water meniscus and explain its shape in terms of the adhesive attraction of the water to the glass. Then they study capillary tubes and observe water climbing due to capillary action in the glass tubes. Finally, students experience a real-world application of capillary action by designing and using "capillary siphons" to filter water.

NSF CAREER Award and RET Program, Mechanical Engineering and Material Science,

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

2005-04-01

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; Peigui Yin; Shaochang Wo

2004-10-01

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; Herbert Fischer; Yu Li; Geoffrey Mason; Douglas Ruth; Siddhartha Seth; Peigui Yin; Shaochang Wo

2005-02-01

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

2004-05-01

7

Silicon ribbon growth by a capillary action shaping technique  

NASA Technical Reports Server (NTRS)

The crystal-growth method under investigation is a capillary action shaping technique. Meniscus shaping for the desired ribbon geometry occurs at the vertex of a wettable dye. As ribbon growth depletes the melt meniscus, capillary action supplies replacement material. The configuration of the technique used in our initial studies is shown. The crystal-growth method has been applied to silicon ribbons it was found that substantial improvements in ribbon surface quality could be achieved with a higher melt meniscus than that attainable with the EFG technique.

Schwuttke, G. H.; Ciszek, T. F.; Kran, A.; Yang, K.

1977-01-01

8

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

9

Silicon ribbon growth by a capillary action shaping technique  

NASA Technical Reports Server (NTRS)

Substantial improvements in ribbon surface quality are achieved with a higher melt meniscus than that attainable with the film-fed (EFG) growth technique. A capillary action shaping method is described in which meniscus shaping for the desired ribbon geometry occurs at the vertex of a wettable die. As ribbon growth depletes the melt meniscus, capillary action supplies replacement material. Topics discussed cover experimental apparatus and growth procedures; die materials investigations, fabrication and evaluation; process development for 25 mm, 38 mm, 50 mm and 100 mm silicon ribbons; and long grain direct solidification of silicon. Methods for the structural and electrical characterization of cast silicon ribbons are assessed as well as silicon ribbon technology for the 1978 to 1986 period.

Schwuttke, G. H.; Schwuttke, G. H.; Ciszek, T. F.; Kran, A.

1977-01-01

10

Moving On Up: Capillary Action II  

NSDL National Science Digital Library

Learners explore capillary action in plants (such as plants ability to move water from roots to leaves) in an investigation called Paper Blooms. Placing paper flowers in water mixed with food coloring, learners observe how water moves through a flower. Students can then try the activity using different fluids such as soapy water or salty water. In the investigation Toothpick Tricks learners observe slightly different capillary action in simple models of flowers made with toothpicks.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

11

Moving On Up: Capillary Action 1  

NSDL National Science Digital Library

Over the course of several days, learners explore the property of water that helps plants move water from roots to leaves or gives paper towels the capacity to soak up water. Learners will observe water's ability to move through narrow tube-like spaces known as capillaries, in an investigation called Colorizing Carnations. Learners then modify the variables in their activity to test how capillary action is affected by soapy water, salty water, different liquids and/or different plants.

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

12

County Science Fair 2006 How temperature affects capillary action  

E-print Network

County Science Fair 2006 How temperature affects capillary action Abe Karplus 4th grade · Spring temperature affects capillary action What my experiment is about My experiment is about how the temperature as capillary action. My second experiment is about how the temperature of water in a jar will affect how long

Karplus, Kevin

13

Science Fair 2006 How temperature affects capillary action  

E-print Network

Science Fair 2006 How temperature affects capillary action Abe Karplus 4th grade · Spring Hill School · February 7, 2006 Abe Karplus · Spring Hill School! #12;Science Fair 2006 How temperature affects capillary action What my experiment is about My experiment is about how the temperature of water in a jar

Karplus, Kevin

14

High-resolution x-ray tomography imaging of supercritical CO2: Investigating capillary trapping under reservoir conditions and addressing wettability alteration  

NASA Astrophysics Data System (ADS)

In geological carbon sequestration, CO2 is stored in a supercritical state in subsurface reservoirs. Deep saline aquifers are particularly attractive because of their abundance and potentially large storage volumes. Despite very broad research efforts there are still substantial uncertainties related to the effectiveness of the trapping processes controlling the permanent storage of CO2. After injection of CO2 the saline water (brine) will imbibe back and reoccupy the pore space as the buoyant CO2 moves upwards. Some of the CO2 will remain behind in a trapping mechanism known as capillary trapping that occurs as CO2 bubbles are isolated by the brine inside some of the pore space. The large-scale movement of the trapped CO2 within the brine is thereby prevented. Capillary trapping thus constitutes an important storage mechanism following CO2 injection until subsequent aqueous dissolution and precipitation of carbonate minerals depletes the reservoir of free-phase CO2. We present pressure-saturation curves derived from drainage and imbibition experiments with brine and supercritical CO2 at 1200 PSI and at 36C for Bentheimer sandstone cores. We compare the supercritical CO2 experiments with ambient pressure and temperature experiments using water and air (supercritical CO2 proxy fluid) for Bentheimer sandstone. The pressure-saturation curves are accompanied with quantitative results on non-wetting phase saturation, topology and connectivity as determined from three-dimensional (3D) images. The 3D data with a resolution of 4.65 ?m were derived from high-resolution synchrotron x-ray computed micro-tomography (CMT), collected at the GSECARS beam line 13-BM-D at the Advanced Photon Source, Argonne National Laboratory. Drainage and imbibition experiments, performed under ambient pressure and temperature conditions, indicate that the topology of the non-wetting phase after drainage correlates with the final trapping of the non-wetting phase, after imbibition. Pressure-saturation curves obtained for supercritical CO2 and water at reservoir conditions (1200 PSI and 36C), point towards a wettability alteration of the Bentheimer sandstone upon contact with supercritical CO2.

Andersson, L.; Herring, A. L.; Newell, D. L.; Carey, B.; Wildenschild, D.

2013-12-01

15

Simulation of Oil Displacement from Oil-Wet Cores by Interfacial Tension Reduction and Wettability Alteration  

E-print Network

wettability toward water-wet may increase spontaneous imbibition of water. This change in rock wettability leads to positive capillary pressure and results in higher brine counter-current imbibition and therefore a higher oil production rate. A three...

Kalaei, Mohammad Hosein

2010-01-29

16

Measuring wettability of unconsolidated oil sands using the USBM method  

Microsoft Academic Search

The commercial development of bitumen production by cyclic steam stimulation in Cold Lake, Alberta, Canada has prompted the need to acquire relevant capillary pressure and wettability data. The USBM method was used to determine the wettability of four adjacent Cold Lake Clearwater cores at 40C using a heated centrifuge. A centrifuge core holder that provides confining pressure and enforces zero

Mori Y Kwan

1998-01-01

17

Emission Property of Composite Micro Tubule Cathode Molded by Capillary Action  

Microsoft Academic Search

A conductive polymer composite was used in fabrication of field emission(FE) electrode array. The FE electrode was prepared by using a template: polycarbonate membrane filter of 0.4?1.2?m diameter pores. Initially, the conductive polymer was spin-coated on the ITO glass. Polymer tubules were molded by capillary action of the polymer solution into the template. After removing the template, metal were deposited

Kyoung Hwa Kim; Yongkeun Son; Youngkwan Lee; Sung Yun Jeon; Jae-Hong Pack; Ji-Beom Yoo

2007-01-01

18

Insulin-mediated capillary recruitment in skeletal muscle: Is this a mediator of insulin action on glucose metabolism?  

Microsoft Academic Search

The possibility that insulin stimulates microvascular access for itself and glucose in muscle in vivo is discussed. The application\\u000a of new techniques suggests that capillary recruitment is a normal part of insulin's action and that this process becomes impaired\\u000a in insulin resistance. Exercise, which also leads to capillary recruitment, may involve a different mechanism than that used\\u000a by insulin.

Stephen Rattigan; Eugene J. Barrett; Michael G. Clark

2003-01-01

19

Capillary Action may be used in feeding Particles and as calorimeters in Accelerators  

NASA Astrophysics Data System (ADS)

Capillary Action was first proposed to be a Quantum Mechanical Effect by this Author. In plants it takes no work for water to travel up a tree, a flow of fluid begins when a thermal photon causes the water at the top of the column to evaporate. When the molecule evaporates a ``hole'' is transfered down the water column to the roots where apparently the ``hole'' establishes a ``current'' of ``holes'' in the manner of theory which is superior to the theory of ``solid-state'' physics. The ``hole'' can also be used in a ``path-integral'' formulation as is done in particle physics. A particle (a thermal photon) would strike the surface at the top of the column in through some ``spring'' method cause the whole column to rise--which is an interesting variation of the ``spring-in-mattress'' model used in Quantum Field Theory. Obviously a proper size tube- say a nanotube could be coupled to an Accelerator and the Quantum Field Theory Calculation of the Beam could be used to couple with the ``spring'' field available in the Tube. For the right sized tube, a Calorimeter would be the result. For other sized tubes, the beam could be fed with molecules and particles that have similar characteristics to water. Capillary Action is an example of Particle Physics seen in directly in the Classical world.

Kriske, Richard

2012-11-01

20

Effect of wettability on light oil steamflooding  

SciTech Connect

This report summarizes NIPER's research on four interrelated topics for Light Oil Steamflooding. Four interrelated topics are described: The methodology for measuring capillary pressure and wettability at elevated temperature, the use of silylating agents to convert water-wet Berea sandstones or unconsolidated quartz sands to oil-wetted surfaces, the evaluation of the thermal hydrolytic stability of these oil-wet surfaces for possible use in laboratory studies using steam and hot water to recover oil, and the effect of porous media of different wettabilities on oil recovery where the porous media is first waterflooded and then steamflooded.

Olsen, D.K.

1991-12-01

21

Effect of wettability on light oil steamflooding  

SciTech Connect

This report summarizes NIPER`s research on four interrelated topics for Light Oil Steamflooding. Four interrelated topics are described: The methodology for measuring capillary pressure and wettability at elevated temperature, the use of silylating agents to convert water-wet Berea sandstones or unconsolidated quartz sands to oil-wetted surfaces, the evaluation of the thermal hydrolytic stability of these oil-wet surfaces for possible use in laboratory studies using steam and hot water to recover oil, and the effect of porous media of different wettabilities on oil recovery where the porous media is first waterflooded and then steamflooded.

Olsen, D.K.

1991-12-01

22

A study of heat transfer during steam condensation on a horizontal tube placed in granular material made of particles with different wettability of surface  

NASA Astrophysics Data System (ADS)

The dependence of the equivalent radius of a threshold channel on the diameter of particles during combined action of capillary and mass forces is experimentally obtained. Experimental data on heat transfer during steam condensation on a horizontal tube placed in well- and partially wettable granular layers are presented. It is shown that no enhancement of heat transfer occurs in these layers as compared with that in case of a plain tube.

Bogomolov, A. R.; Petrik, P. T.; Azikhanov, S. S.

2009-07-01

23

Automatic Sampling and Analysis of Organics and Biomolecules by Capillary Action-Supported Contactless Atmospheric Pressure Ionization Mass Spectrometry  

PubMed Central

Contactless atmospheric pressure ionization (C-API) method has been recently developed for mass spectrometric analysis. A tapered capillary is used as both the sampling tube and spray emitter in C-API. No electric contact is required on the capillary tip during C-API mass spectrometric analysis. The simple design of the ionization method enables the automation of the C-API sampling system. In this study, we propose an automatic C-API sampling system consisting of a capillary (?1 cm), an aluminium sample holder, and a movable XY stage for the mass spectrometric analysis of organics and biomolecules. The aluminium sample holder is controlled by the movable XY stage. The outlet of the C-API capillary is placed in front of the orifice of a mass spectrometer, whereas the sample well on the sample holder is moved underneath the capillary inlet. The sample droplet on the well can be readily infused into the C-API capillary through capillary action. When the sample solution reaches the capillary outlet, the sample spray is readily formed in the proximity of the mass spectrometer applied with a high electric field. The gas phase ions generated from the spray can be readily monitored by the mass spectrometer. We demonstrate that six samples can be analyzed in sequence within 3.5 min using this automatic C-API MS setup. Furthermore, the well containing the rinsing solvent is alternately arranged between the sample wells. Therefore, the C-API capillary could be readily flushed between runs. No carryover problems are observed during the analyses. The sample volume required for the C-API MS analysis is minimal, with less than 1 nL of the sample solution being sufficient for analysis. The feasibility of using this setup for quantitative analysis is also demonstrated. PMID:23762484

Hsieh, Cheng-Huan; Meher, Anil Kumar; Chen, Yu-Chie

2013-01-01

24

Wettability alteration in carbonates  

Microsoft Academic Search

Fractured oil-wet carbonate reservoirs are often located at low temperatures and pressures, and the oil recovery by pure pressure depletion is usually low. The potential for improved oil recovery (IOR) is therefore very high. An IOR method is to change the wettability of the reservoir towards more water-wet conditions so that water can spontaneously imbibe into the matrix blocks and

Dag C Standnes; Tor Austad

2003-01-01

25

Impact of wettability correlations on multiphase flow through porous media  

NASA Astrophysics Data System (ADS)

In the last decades, significant progress has been made toward understanding the multiphase displacement through porous media and the role of substrate properties like homogeneous wettability or pore geometry. However, the effect of heterogeneous wettability at microscopic scales and its relation to large-scale properties, like relative permeability or capillary pressure, remains still little understood. In the present study forced imbibition through a two-dimensional porous medium is simulated at the pore scale by means of a mesoscopic particle approach [1,2]. The substrate is described as an assembly of non-overlapping circular disks whose preferential wettability is distributed according to prescribed correlations, i.e., from pore scale in terms of Janus beads up to domains at system scale. We analyze how this well-defined heterogeneous wettability affects the dynamics and try to establish a relationship among wettability-correlations and large-scales properties of the multiphase flow. References [1] Y. Inoue et al., J. Comp. Phys. 201, 191 (2004) [2] G. Gompper et al., Adv. Polym. Sci. 221, 1 (2009)

Sanchez de La Lama, Marta; Brinkmann, Martin; Herminghaus, Stephan

2011-11-01

26

Wettability of graphene.  

PubMed

Graphene, an atomically thin two-dimensional material, has received significant attention due to its extraordinary electronic, optical, and mechanical properties. Studies focused on understanding the wettability of graphene for thermo-fluidic and surface-coating applications, however, have been sparse. Meanwhile, wettability results reported in literature via static contact angle measurement experiments have been contradictory and highlight the lack of clear understanding of the underlying physics that dictates wetting behavior. In this work, dynamic contact angle measurements and detailed graphene surface characterizations were performed to demonstrate that the defects present in CVD grown and transferred graphene coatings result in unusually high contact angle hysteresis (16-37) on these otherwise smooth surfaces. Hence, understanding the effect of the underlying substrate based on static contact angle measurements as reported in literature is insufficient. The advancing contact angle measurements on mono-, bi-, and trilayer graphene sheets on copper, thermally grown silica (SiO2), and glass substrates were observed to be independent of the number of layers of graphene and in good agreement with corresponding molecular dynamics simulations and theoretical calculations. Irrespective of the number of graphene layers, the advancing contact angle values were also in good agreement with the advancing contact angle on highly ordered pyrolytic graphite (HOPG), reaffirming the negligible effect of the underlying substrate. These results suggest that the advancing contact angle is a true representation of a graphene-coated surface while the receding contact angle is significantly influenced by intrinsic defects introduced during the growth and transfer processes. These observations, where the underlying substrates do not affect the wettability of graphene coatings, is shown to be due to the large interlayer spacing resulting from the loose interlamellar coupling between the graphene sheet and the underlying substrate. The fundamental insights on graphene-water interactions reported in this study is an important step towards developing graphene-assisted surface coatings for heat transfer and microfluidics devices. PMID:23458704

Raj, Rishi; Maroo, Shalabh C; Wang, Evelyn N

2013-04-10

27

Enhancing Dropwise Condensation through Bioinspired Wettability Patterning.  

PubMed

Dropwise condensation (DWC) heat transfer depends strongly on the maximum diameter (Dmax) of condensate droplets departing from the condenser surface. This study presents a facile technique implemented to gain control of Dmax in DWC within vapor/air atmospheres. We demonstrate how this approach can enhance the corresponding heat transfer rate by harnessing the capillary forces in the removal of the condensate from the surface. We examine various hydrophilic-superhydrophilic patterns, which, respectively, sustain and combine DWC and filmwise condensation on the substrate. The material system uses laser-patterned masking and chemical etching to achieve the desired wettability contrast and does not employ any hydrophobizing agent. By applying alternating straight parallel strips of hydrophilic (contact angle ?78) mirror-finish aluminum and superhydrophilic regions (etched aluminum) on the condensing surface, we show that the average maximum droplet size on the less-wettable domains is nearly 42% of the width of the corresponding strips. An overall improvement in the condensate collection rate, up to 19% (as compared to the control case of DWC on mirror-finish aluminum) was achieved by using an interdigitated superhydrophilic track pattern (on the mirror-finish hydrophilic surface) inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern design, particularly under higher humidity conditions in the presence of noncondensable gases (NCG), a condition that is more challenging for maintaining sustained DWC. PMID:25295388

Ghosh, Aritra; Beaini, Sara; Zhang, Bong June; Ganguly, Ranjan; Megaridis, Constantine M

2014-11-01

28

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 solidliquid 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. PMID:20596284

2009-01-01

29

Capillary sample  

MedlinePLUS

... using capillary blood sampling. Disadvantages to capillary blood sampling include: Only a limited amount of blood can be drawn using this method. The procedure has some risks (see below). Capillary ...

30

Extreme wettability due to dendritic copper nanostructure via electrodeposition  

NASA Astrophysics Data System (ADS)

Dendritic copper film with convertible extreme wettability is prepared on metal surface via electrodeposition. With field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and electrochemical measurement, the morphology, composition and formation mechanism of dendritic copper film were studied. It is found that the film is mainly composed of metallic copper. Also some residual cuprous oxide and chloride exist in the deposit. The single micron-sized dendrite consists of a main stem with side branches, on which the higher-order branches with the dimension of tens of nanometers grow. A hydrophobic modification can induce the conversion of the apparent wettability of film from super-hydrophilicity (with apparent water contact angle of 5 3) to super-hydrophobicity (with apparent water contact angle of 154.1 3), which is due to the capillary effect. The method proposed in this paper is time-saving and facile to operate, and it offers a promising technique to prepare metallic surface with a high wettability contrast for water.

Wang, Peng; Zhang, Dun; Qiu, Ri

2011-08-01

31

The effect of wettability on capillary pressure and oil recovery  

E-print Network

) (&) (gm/cc) All A12 Bll 812 Cll C12 Dll D12 A21 A22 821 B22 C21 C22 D21 D22 A31 A32 B31 B32 C31 C32 D31 D32 5. 083 4. 956 5. 027 5. 011 4. 846 4. 857 4. 999 4. 877 4. 971 4. 989 4. 902 4. 930 4. 976 4. 986 4. 951 4... cores were lower than those 30 TABLE 5. COMPARISON OF PHYSICAL PROPERTIES BETWEEN CORES BEFORE AND AFTER TREATMENT Before Treatm t After Treatment Core Pore Vol No. (cc) Porosity Density (&) (gm/cc) Pore Vol. Porosity Density (cc) (&) (gm/cc) All...

Chon, Bohyun

2012-06-07

32

New concept for coal wettability evaluation and modulation. Technical progress report, October 1, 1993--December 31, 1993  

SciTech Connect

This project is concerned concept for coal surface wettability evaluation and modulation. The objective of the work are to study the fundamental surface chemistry feature about the evaluation of the surface of coal, pyrite and coal pyrite, and also establish a new separation strategy which could contribute to the advanced coal cleaning for premium fuel application. In this quarter, the capillary rise of three coals, colorado mineral pyrite, and coal pyrite in butanol, pentanol, and butyl ether have been tested. The test results shown that the kinetic wettability of the five samples in the alcohol homolog are dependent on the carbon chain length, as the length of the carbon chain is shorter, the surface wettability is the better. Another test results shown that the kinetic wettability of coals are better than mineral pyrite and coal pyrite in the butyl ether.

Hu, Weibai

1993-12-31

33

Wettability by molten oxides of copper and silver with a change in the aggregate condition of the surface being wetted  

Microsoft Academic Search

Knowledge of the capillary properties (wettability, work of adhesion) of the contacting phases during the solid--liquid phase transformation of the surface being wetted is necessary, for example, for revealing features of the interphase interaction and solution of a number of technical problems, in particular in powder metallurgy in production of composite materials (such as metal oxide ones) or during liquid-phase

Yu. V. Naidich; V. M. Perevertailo; V. V. Poluyanskaya; I. N. Krasnobaeva

1987-01-01

34

Tunable wettability of microstructured polypyrrole films  

E-print Network

This thesis presents the development of the conducting polymer polypyrrole as a viable material for applications requiring switchable wettability. A fabrication procedure that produces robust microstructured polypyrrole ...

Chang, Jean H

2010-01-01

35

Wettability evaluation of Iranian carbonate formations  

Microsoft Academic Search

The evaluation of wettability of carbonate rock samples of Iranian formations has been investigated using relative permeability curves and Amott tests. The experiments have been performed at both ambient and reservoir temperature to study the temperature effect on wettability evaluation of carbonate rocks. The samples were carefully cleaned and aged at reservoir temperature in order to achieve restoration of reservoir

Mohammad Reza Esfahani; Manouchehr Haghighi

2004-01-01

36

Effects of surface wettability and liquid viscosity on the dynamic wetting of individual drops  

NASA Astrophysics Data System (ADS)

In this paper, we experimentally investigated the dynamic spreading of liquid drops on solid surfaces. Drop of glycerol water mixtures and pure water that have comparable surface tensions (62.3-72.8 mN/m) but different viscosities (1.0-60.1 cP) were used. The size of the drops was 0.5-1.2 mm. Solid surfaces with different lyophilic and lyophobic coatings (equilibrium contact angle ?eq of 0-112) were used to study the effect of surface wettability. We show that surface wettability and liquid viscosity influence wetting dynamics and affect either the coefficient or the exponent of the power law that describes the growth of the wetting radius. In the early inertial wetting regime, the coefficient of the wetting power law increases with surface wettability but decreases with liquid viscosity. In contrast, the exponent of the power law does only depend on surface wettability as also reported in literature. It was further found that surface wettability does not affect the duration of inertial wetting, whereas the viscosity of the liquid does. For low viscosity liquids, the duration of inertial wetting corresponds to the time of capillary wave propagation, which can be determined by Lamb's drop oscillation model for inviscid liquids. For relatively high viscosity liquids, the inertial wetting time increases with liquid viscosity, which may due to the viscous damping of the surface capillary waves. Furthermore, we observed a viscous wetting regime only on surfaces with an equilibrium contact angle ?eq smaller than a critical angle ?c depending on viscosity. A scaling analysis based on Navier-Stokes equations is presented at the end, and the predicted ?c matches with experimental observations without any additional fitting parameters.

Chen, Longquan; Bonaccurso, Elmar

2014-08-01

37

Influence of capillary forces on the regime of water evaporation in high-temperature rocks  

Microsoft Academic Search

A one-dimensional problem of the injection of water into a geothermal reservoir saturated with a superheated vapor in the\\u000a presence of capillary forces has been investigated in an isothermal approximation. It is shown that in wettable rocks the\\u000a capillary forces increase the velocity of motion of the front and decrease it in unwettable ones. If the capillary forces\\u000a play a

G. G. Tsypkin; C. Calore

2008-01-01

38

Capillary-Driven Flow in Liquid Filaments Connecting Orthogonal Channels  

NASA Technical Reports Server (NTRS)

Capillary phenomena plays an important role in the management of product water in PEM fuel cells because of the length scales associated with the porous layers and the gas flow channels. The distribution of liquid water within the network of gas flow channels can be dramatically altered by capillary flow. We experimentally demonstrate the rapid movement of significant volumes of liquid via capillarity through thin liquid films which connect orthogonal channels. The microfluidic experiments discussed provide a good benchmark against which the proper modeling of capillarity by computational models may be tested. The effect of surface wettability, as expressed through the contact angle, on capillary flow will also be discussed.

Allen, Jeffrey S.

2005-01-01

39

Asymmetric Wettability Directs Leidenfrost Droplets  

SciTech Connect

Leidenfrost phenomena on nano- and microstructured surfaces are of great importance for increasing control over heat transfer in high power density systems utilizing boiling phenomena. They also provide an elegant means to direct droplet motion in a variety of recently emerging fluidic systems. Here, we report the fabrication and characterization of tilted nanopillar arrays (TNPAs) that exhibit directional Leidenfrost water droplets under dynamic conditions, namely on impact with Weber numbers 40 at T 325 C. The batch fabrication of the TNPAs was achieved by glancing-angle anisotropic reactive ion etching of a thermally dewet platinum mask, with mean pillar diameters of 100 nm and heights of 200-500 nm. In contrast to previously implemented macro- and microscopic Leidenfrost ratchets, our TNPAs induce no preferential directional movement of Leidenfrost droplets under conditions approaching steady-state film boiling, suggesting that the observed droplet directionality is not a result of asymmetric vapor flow. Using high-speed imaging, phase diagrams were constructed for the boiling behavior upon impact for droplets falling onto TNPAs, straight nanopillar arrays, and smooth silicon surfaces. The asymmetric impact and directional trajectory of droplets was exclusive to the TNPAs for impacts corresponding to the transition boiling regime, revealing that asymmetric wettability upon impact is the mechanism for the droplet directionality.

Agapov, Rebecca L [ORNL] [ORNL; Boreyko, Jonathan B [ORNL] [ORNL; Briggs, Dayrl P [ORNL] [ORNL; Srijanto, Bernadeta R [ORNL] [ORNL; Retterer, Scott T [ORNL] [ORNL; Collier, Pat [ORNL] [ORNL; Lavrik, Nickolay V [ORNL] [ORNL

2014-01-01

40

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

41

Pulsating flow driven alteration in moving contact-line dynamics on surfaces with patterned wettability gradients  

NASA Astrophysics Data System (ADS)

The contact line dynamics over surfaces patterned with wettability gradients under pulsating flow condition are of essential importance in application areas ranging from the design of smart and effective microfluidic devices to the understanding of blood flow dynamics in narrow conduits. In the present study, we probe the capillary filling dynamics in a pulsatile flow environment, in an effort to explore the underlying flow physics. Presenting the results of frequency assisted contact line motion of two immiscible fluids over surfaces patterned with wettability gradients, we show how the interfacial dynamics are affected by the interplay of both the surface characteristics and flow pulsation. Our results reveal that the competition between two control parameters, the frequency and the amplitude of the imposed flow pulsation, may effectively be tuned to control the capillary filling dynamics significantly. The study, we present here, also suggests that by suitably tuning the control parameters, it is possible to control the capillary residence time over engineered locations which may, in turn, facilitate improved mixing and/or design of chemically active reaction stations.

Mondal, Pranab Kumar; DasGupta, Debabrata; Bandopadhyay, Aditya; Chakraborty, Suman

2014-08-01

42

High-throughput screening using the differential radial capillary action of ligand assay identifies ebselen as an inhibitor of diguanylate cyclases.  

PubMed

The rise of bacterial resistance to traditional antibiotics has motivated recent efforts to identify new drug candidates that target virulence factors or their regulatory pathways. One such antivirulence target is the cyclic-di-GMP (cdiGMP) signaling pathway, which regulates biofilm formation, motility, and pathogenesis. Pseudomonas aeruginosa is an important opportunistic pathogen that utilizes cdiGMP-regulated polysaccharides, including alginate and pellicle polysaccharide (PEL), to mediate virulence and antibiotic resistance. CdiGMP activates PEL and alginate biosynthesis by binding to specific receptors including PelD and Alg44. Mutations that abrogate cdiGMP binding to these receptors prevent polysaccharide production. Identification of small molecules that can inhibit cdiGMP binding to the allosteric sites on these proteins could mimic binding defective mutants and potentially reduce biofilm formation or alginate secretion. Here, we report the development of a rapid and quantitative high-throughput screen for inhibitors of protein-cdiGMP interactions based on the differential radial capillary action of ligand assay (DRaCALA). Using this approach, we identified ebselen as an inhibitor of cdiGMP binding to receptors containing an RxxD domain including PelD and diguanylate cyclases (DGC). Ebselen reduces diguanylate cyclase activity by covalently modifying cysteine residues. Ebselen oxide, the selenone analogue of ebselen, also inhibits cdiGMP binding through the same covalent mechanism. Ebselen and ebselen oxide inhibit cdiGMP regulation of biofilm formation and flagella-mediated motility in P. aeruginosa through inhibition of diguanylate cyclases. The identification of ebselen provides a proof-of-principle that a DRaCALA high-throughput screening approach can be used to identify bioactive agents that reverse regulation of cdiGMP signaling by targeting cdiGMP-binding domains. PMID:24134695

Lieberman, Ori J; Orr, Mona W; Wang, Yan; Lee, Vincent T

2014-01-17

43

Impact of wettability on two-phase displacement patterns in granular media  

NASA Astrophysics Data System (ADS)

Two-phase flow in porous media is important in many natural and industrial processes like geologic CO2 sequestration, enhanced oil recovery, water infiltration in soil, and methane venting from organic-rich sediments. While the wetting properties of porous media can vary drastically depending on the type of media and the pore fluids, the effect of wettability on the fluid displacement remains poorly understood. Here, we study experimentally how wettability affects fluid displacement patterns in rigid granular media within the capillary and viscous fingering regimes. The experiments consist of saturating a thin bed of glass beads with a viscous fluid, injecting a less viscous fluid, and imaging the invasion morphology. There are two control parameters: the injection rate of the less viscous fluid and the contact angle, which we control by modifying the surface chemistry of the beads. When the contact angle is fixed at zero (drainage), we recover the well-known transition from capillary fingering to viscous fingering as the injection rate is increased. When the injection rate is fixed, we show that the invasion pattern becomes more stable as the contact angle increases (i.e., as the system transitions from drainage to imbibition), both in the capillary-fingering and viscous-fingering regimes. We quantify the effect of the contact angle on the length scale of the instability, and propose a mechanistic pore-scale model that explains the macroscopic observations. The results demonstrate that wettability can significantly impact multiphase flow in porous media, and highlight the need to better understand the specific effects in many processes such as CO2 sequestration and enhanced oil recovery. Air displacing a water/glycerol mixture within a radial Hele-Shaw cell filled with glass beads. Varying the wetting properties of the solid matrix (horizontal axis) as well as the injection rate (vertical axis) systematically, the invasion pattern stabilizes as the invading phase (air) becomes more wetting.

Trojer, M.; Szulczewski, M.; Holtzman, R.; Juanes, R.

2013-12-01

44

Influence of surfactant structure on wettability modification of hydrophobic granular surfaces  

SciTech Connect

Using the capillary penetration wetting technique, the influence of surfactant structure on wettability modification of hydrophobic granular surfaces was examined. Linear and branched hydrocarbon chain sulfates, 5 mol monodisperse ethoxylates and 5 mol monodisperse ethoxysulfates were used as surfactants and resin-coated sand as the hydrophobic granular surface. Both the surfactant type and hydrocarbon chain branching were observed to exert a significant influence on the rate and effectiveness of wetting. Wetting rates for ethoxylates > sulfates > ethoxysulfates. Wetting effectiveness for sulfates > ethoxylates. For a given surfactant type, hydrocarbon chain branching was observed to increase wetting rate and effectiveness.

Varadaraj, R.; Bock, J.; Brons, N.; Zushma, S. (Exxon Research and Engineering Co., Annandale, NJ (United States))

1994-10-01

45

Spontaneous imbibition and wettability characteristics of Powder River Basin coal  

Microsoft Academic Search

The wettability of coal is studied at scales that range from the microscopic to the core. While contact-angle measurements define wettability at microscopic (pore) and core scales, relative permeability curves define wettability and multiphase flow properties at core and reservoir scales. The microscopic wettability is evaluated based on the FrumkinDerjaguin equation. Estimates for contact angles are made versus aqueous-phase pH.

T. Chaturvedi; J. M. Schembre; A. R. Kovscek

2009-01-01

46

Effects of radiofrequency glow discharge on impression material surface wettability  

Microsoft Academic Search

Statement of problem. Argon radiofrequency glow discharge (RGD) may simultaneously sterilize and improve surface wettability of impression materials.Purpose. The purpose of this study was to define RGD technical parameters that influence the surface wettability of impression material (optimization phase). Definition of RGD was followed by an assessment of these optimized RGD parameters on the wettability of four impression materials either

Richard M. Hesby; Chris R. Haganman; Clark M. Stanford

1997-01-01

47

Design of capillary flows with functionally graded porous titanium oxide films fabricated by anodization instability.  

PubMed

We have developed an electrochemical fabrication method utilizing breakdown anodization (BDA) to yield capillary flows that can be expressed as functions of capillary height. This method uses anodization instability with high electric potentials and mildly acidic electrolytes that are maintained at low temperature. BDA produces highly porous micro- and nano-structured surfaces composed of amorphous titanium oxide on titanium substrates, resulting in high capillary pressure and capillary diffusivity. With this fabrication technique the capillary flow properties can be controlled by varying the applied electric field and electrolyte temperature. Furthermore, they can be expressed as functions of capillary height when customized electric fields are used in BDA. To predict capillary flows on BDA surfaces, we developed a conceptual model of highly wettable porous films, which are modeled as multiple layers of capillary tubes oriented in the flow direction. From the model, we derived a general capillary flow equation of motion in terms of capillary pressure and capillary diffusivity, both of which can be expressed as functions of capillary height. The theoretical model was verified by comparisons with experimental capillary flows, showing good agreement. From investigation of the surface morphology we found that the surface structures were also functionally graded with respect to the capillary height (i.e. applied electric field). The suggested fabrication method and the theoretical model offer novel design methodologies for microscale liquid transport devices requiring control over propagation speed. PMID:24703679

Joung, Young Soo; Figliuzzi, Bruno Michel; Buie, Cullen R

2014-06-01

48

Nanofluid boiling: The effect of surface wettability  

Microsoft Academic Search

Nanofluid boiling has shown potential to increase boiling heat transfer, but the mechanisms responsible are poorly understood. One likely mechanism for nanofluid enhancement is an improvement in surface wettability. This study is targeted towards investigating whether or not nanofluids improve the critical heat flux (CHF) by altering the surface energy as has been observed for pure fluids. The surface of

Johnathan S. Coursey; Jungho Kim

2008-01-01

49

Motion of Drops on Surfaces with Wettability Gradients  

NASA Technical Reports Server (NTRS)

A liquid drop present on a solid surface can move because of a gradient in wettability along the surface, as manifested by a gradient in the contact angle. The contact angle at a given point on the contact line between a solid and a liquid in a gaseous medium is the angle between the tangent planes to the liquid and the solid surfaces at that point and is measured within the liquid side, by convention. The motion of the drop occurs in the direction of increasing wettability. The cause of the motion is the net force exerted on the drop by the solid surface because of the variation of the contact angle around the periphery. This force causes acceleration of an initially stationary drop, and leads to its motion in the direction of decreasing contact angle. The nature of the motion is determined by the balance between the motivating force and the resisting hydrodynamic force from the solid surface and the surrounding gaseous medium. A wettability gradient can be chemically induced as shown by Chaudhury and Whitesides who provided unambiguous experimental evidence that drops can move in such gradients. The phenomenon can be important in heat transfer applications in low gravity, such as when condensation occurs on a surface. Daniel et al have demonstrated that the velocity of a drop on a surface due to a wettability gradient in the presence of condensation can be more than two orders of magnitude larger than that observed in the absence of condensation. In the present research program, we have begun to study the motion of a drop in a wettability gradient systematically using a model system. Our initial efforts will be restricted to a system in which no condensation occurs. The experiments are performed as follows. First, a rectangular strip of approximate dimensions 10 x 20 mm is cut out of a silicon wafer. The strip is cleaned thoroughly and its surface is exposed to the vapor from an alkylchlorosilane for a period lasting between one and two minutes inside a desiccator. This is done using an approximate line source of the vapor in the form of a string soaked in the alkylchlorosilane. Ordinarily, many fluids, including water, wet the surface of silicon quite well. This means that the contact angle is small. But the silanized surface resists wetting, with contact angles that are as large as 100 degs. Therefore, a gradient of wettability is formed on the silicon surface. The region near the string is highly hydrophobic, and the contact angle decreases gradually toward a small value at the hydrophilic end away from this region. The change in wettability occurs over a distance of several mm. The strip is placed on a platform within a Plexiglas cell. Drops of a suitable liquid are introduced on top of the strip near the hydrophobic end. An optical system attached to a video camera is trained on the drop so that images of the moving drop can be captured on videotape for subsequent analysis. We have performed preliminary experiments with water as well as ethylene glycol drops. Results from these experiments will be presented in the poster. Future plans include the refinement of the experimental system so as to permit images to be recorded from the side as well as the top, and the conduct of a systematic study in which the drop size is varied over a good range. Experiments will be conducted with different fluids so as to obtain the largest possible range of suitably defined Reynolds and Capillary numbers. Also, an effort will be initiated on theoretical modeling of this motion. The challenges in the development of the theoretical description lie in the proper analysis of the region in the vicinity of the contact line, as well as in the free boundary nature of the problem. It is known that continuum models assuming the no slip condition all the way to the contact line fail by predicting that the stress on the solid surface becomes singular as the contact line is approached. One approach for dealing with this issue has been to relax the no-slip boundary condition using the Navier model. Molecular dynamics simulations of the contact li

Subramanian, R. Shankar; McLaughlin, John B.; Moumen, Nadjoua; Qian, Dongying

2002-01-01

50

CO2 Reaction Induced Wettability Alteration and its Impacts on CO2 Storage: Pore to Core Scale Reservoir Condition Experimental Studies  

NASA Astrophysics Data System (ADS)

Wettability of the mineral surfaces plays an important role in subsurface multiphase flow and transport. Wettability affects the capillary pressure-saturation (Pc- S) relations, relative permeability (kr) of each fluid phase, and relative phase occupancy in reservoir pores. Although wettability issues have been studied extensively in other fields, significant knowledge gaps remain when applying the existing understanding to geological carbon sequestration; due largely to the unique physical-chemical properties of supercritical (sc) CO2 relative to other common non-wetting fluids such as air and oil. Here, we report our recent progress on wettability alteration upon reaction with CO2 and the resulting differences in capillary trapping of CO2 versus air. (1) Pore Scale Studies. There are conflict predictions in the literature concerning the effect of wettability on capillary trapping; some find that larger contact angles lead to lower capillary trapping while others have found opposite behavior. We hypothesized that spontaneous imbibition becomes energetically unfavorable with decreased wettability, so that increased residual trapping of scCO2 should occur during the post-injection inbibition stage. We developed a laboratory high-pressure and elevated temperature microscopic-micromodel system that is capable of controlling fine scale capillary pressure of scCO2-brine, and enabled us to conduct imbibition under controlled capillary pressures at the pore scale. We found that the de-wetting enhanced scCO2 capillary trapping is significant. These results suggest that scCO2 reaction induced dewetting can result in higher degrees of CO2 residual trapping in the post-injection stage than previously predicted. (2) Core Scale Studies. Capillary scaling is used routinely to predict Pc(S) relations for scCO2-brine systems at field scale, based on relations measured with air-water or mercury porosimetry. However, scaling-based predictions for CO2-brine systems have not been fully tested. Current limitations include the fact that imbibition curves are seldom measured due to experimental difficulties in controlling capillary pressure, and wettability (contact angles) is usually unknown and applied as adjustable parameters. Applying a new laboratory system to accurately control Pc at high total P, and we measured Pc(S) of a homogeneous quartz sand (selected because its 'normal' hydraulic properties are very well constrained). Drainage and imbibition experiments were conducted to directly measure Pc(S) with air-brine, then with scCO2-brine. With scCO2, intermediate levels of S shifted to Pc values 30% to 90% lower than predicted based on scaling with interfacial tension. Capillary trapping of CO2 were measured at Pc = 0 during brine imbibition, with trapped volumes for scCO2 significantly greater than for trapped air. We conclude that the observed deviations from scaling predictions make predicting the hydraulic behavior of scCO2 in reservoirs more challenging, and that an understanding of scCO2-induced wettability change is needed.

Wan, J.; Tokunaga, T. K.; Kim, Y.; Jung, J.; Kim, T.; Dong, W.

2013-12-01

51

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

PubMed

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. E 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 [Langmuir 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. PMID:23004770

Xu, Xinpeng; Qian, Tiezheng

2012-05-01

52

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

53

Filtration of liquid aerosols on wettable fibrous filters  

SciTech Connect

Liquid aerosols produced in many manufacturing and refining processes need to be filtered from the exhaust streams. Where wettable fibers are used in the filters, the aerosol liquid collects on the fibers. Observation shows that thin films develop on the fibers, and the liquid drains down the fibers under the action of gravity. A model is developed for the flow of liquid in these films, and careful experimentation confirms the nature and importance of the flow pattern. The resultant overall efficiencies of the filter are also calculated from a theoretical analysis and compared with the results of experimentation using counting techniques. The theoretical and experimental results agree excellently for the range of aerosol sizes that are detectable by laser diffraction and cascade impactor techniques.

Agranovski, I.E.; Braddock, R.D. [Griffith Univ., Nathan (Australia)] [Griffith Univ., Nathan (Australia)

1998-12-01

54

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

55

Wettable battery separator and process therefor  

Microsoft Academic Search

A process for imparting permanent wettability to a battery separator comprising a non-woven mat of polyolefin fiber is described. The process comprises impregnating the mat with 0.2 to 30 percent by weight of an ..cap alpha..-olefin\\/..cap alpha..,..beta..-unsaturated acid or anhydride copolymer, the copolymer containing about 5 to about 80 weight percent ..cap alpha..,..beta..-unsaturated acid or anhydride and being dissolved in

W. R. Wszolek; J. A. Cogliana

1974-01-01

56

Bioinspired steel surfaces with extreme wettability contrast.  

PubMed

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. PMID:22456538

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

2012-04-28

57

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

58

Effect of wettability on scale-up of multiphase flow from core-scale to reservoir fine-grid-scale  

SciTech Connect

Typical field simulation grid-blocks are internally heterogeneous. The objective of this work is to study how the wettability of the rock affects its scale-up of multiphase flow properties from core-scale to fine-grid reservoir simulation scale ({approximately} 10{prime} x 10{prime} x 5{prime}). Reservoir models need another level of upscaling to coarse-grid simulation scale, which is not addressed here. Heterogeneity is modeled here as a correlated random field parameterized in terms of its variance and two-point variogram. Variogram models of both finite (spherical) and infinite (fractal) correlation length are included as special cases. Local core-scale porosity, permeability, capillary pressure function, relative permeability functions, and initial water saturation are assumed to be correlated. Water injection is simulated and effective flow properties and flow equations are calculated. For strongly water-wet media, capillarity has a stabilizing/homogenizing effect on multiphase flow. For small variance in permeability, and for small correlation length, effective relative permeability can be described by capillary equilibrium models. At higher variance and moderate correlation length, the average flow can be described by a dynamic relative permeability. As the oil wettability increases, the capillary stabilizing effect decreases and the deviation from this average flow increases. For fractal fields with large variance in permeability, effective relative permeability is not adequate in describing the flow.

Chang, Y.C.; Mani, V.; Mohanty, K.K. [Univ. of Houston, TX (United States)

1997-08-01

59

Water films, asphaltenes, and wettability alteration  

SciTech Connect

We present a transport model for asphaltene diffusion from an oil/water interface through a water film followed by adsorption at a solid/water interface. Using a Langmuir adsorption isotherm, the effect of asphaltene aqueous solubility and adsorption constant K on equilibration time are established. For K greater than 1 nm and asphaltene solubilities down to 0.1 ppb, adsorption equilibrium, taken to be 1 mg/m{sup 2}, occurs within a few hours. Negligible asphaltene solubility does not explain why a water film prevents asphaltene adsorption and wettability alteration in reservoir rock.

Kaminsky, R.; Radke, C.J.

1998-06-01

60

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

61

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

62

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. PMID:22607462

2012-01-01

63

Wettability phenomena at the CO2-brine-mineral interface: implications for geologic carbon sequestration.  

PubMed

Geologic carbon sequestration (GCS) in deep saline aquifers results in chemical and transport processes that are impacted by the wettability characteristics of formation solid phases in contact with connate brines and injected CO(2). Here, the contact angle (?) at the CO(2)-brine-mineral interface is studied for several representative solids including quartz, microcline, calcite, kaolinite, phlogopite, and illite under a range of GCS conditions. All were found to be water wetting (? < 30) with subtle but important differences in contact angles observed between the surfaces. Temperature and pressure conditions affected the results but did not produce discernible trends common to all surfaces. Brine composition, in terms of pH and ionic strength, was a better predictor of interfacial behavior. For the nonclays, the wettability is impacted by the pH at the point of zero charge of the solid. For the clays, the response was more complex. Under nonequilibrium conditions, hysteretic effects were observed when CO(2) was dissolving into the bulk fluid and this effect varied between minerals. Contact angle was found to decrease during the CO(2) phase transition from supercritical or liquid phase to gas phase. These results are useful for developing a more complete understanding of leakage through caprocks and capillary trapping in GCS. PMID:22857395

Wang, Shibo; Edwards, Ian M; Clarens, Andres F

2013-01-01

64

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

65

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. PMID:24149467

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

2013-01-01

66

Molecular dynamics of wetting layer formation and forced water invasion in angular nanopores with mixed wettability.  

PubMed

The depletion of conventional hydrocarbon reservoirs has prompted the oil and gas industry to search for unconventional resources such as shale gas/oil reservoirs. In shale rocks, considerable amounts of hydrocarbon reside in nanoscale pore spaces. As a result, understanding the multiphase flow of wetting and non-wetting phases in nanopores is important to improve oil and gas recovery from these formations. This study was designed to investigate the threshold capillary pressure of oil and water displacements in a capillary dominated regime inside nanoscale pores using nonequilibrium molecular dynamics (NEMD) simulations. The pores have the same cross-sectional area and volume but different cross-sectional shapes. Oil and water particles were represented with a coarse grained model and the NEMD simulations were conducted by assigning external pressure on an impermeable piston. Threshold capillary pressures were determined for the drainage process (water replaced by oil) in different pores. The molecular dynamics results are in close agreements with calculations using the Mayer-Stowe-Princen (MS-P) method which has been developed on the premise of energy balance in thermodynamic equilibrium. After the drainage simulations, a change in wall particles' wettability from water-wet to oil-wet was implemented based on the final configuration of oil and water inside the pore. Waterflooding simulations were then carried out at the threshold capillary pressure. The results show that the oil layer formed between water in the corner and in the center of the pore is not stable and collapses as the simulation continues. This is in line with the predictions from the MS-P method. PMID:25416901

Sedghi, Mohammad; Piri, Mohammad; Goual, Lamia

2014-11-21

67

Non-Reflective, Wettable, Fibrous Fabric Assemblies for Firefighters' Clothing.  

National Technical Information Service (NTIS)

The Navy Clothing and Textile Research Facility (NCTRF) has developed a nonreflective, wettable, firefighters' proximity garment made from water-absorptive fibrous fabric assemblies in combination with a vapor barrier fabric and insulation liner. When wet...

Z. Kupferman

1977-01-01

68

Surface wettability studies of PDMS using flame plasma treatment  

E-print Network

The flame plasma treatment studied in this thesis was able to oxidize the surface of Polydimethylsiloxane (PDMS) in a fraction of a second. It was found to be a much faster way to modify PDMS surface wettability than the ...

Wang, Xin C

2009-01-01

69

Effect of rust on the wettability of steel by water  

SciTech Connect

Rust, as formed on steel by immersion of low-carbon steel in water, was found to improve the wettability of steel by water. The advancing contact angle decreased from 87{degree} to 32{degree}, and the receding contact angle decreased from 81{degree} to 29{degree}. Cleansing of steel by acetone also helped improve the wettability, but the advancing angle only decreased from 87{degree} to 73{degree}, and the receding angle only decreased from 81{degree} to 41{degree}.

Lu, W.; Chung, D.D.L. [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.] [State Univ. of New York, Buffalo, NY (United States). Composite Materials Research Lab.

1998-04-01

70

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

71

Elasto-capillary thinning and breakup of model elastic liquids  

E-print Network

and breakup of polymeric liquid jets. Newtonian jets rapidly neck down under capillary action and pinch offElasto-capillary thinning and breakup of model elastic liquids Shelley L. Anna DivisionKinleya) Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

72

Effective Wettability Measurements of CO2-Brine-Sandstone System at Different Reservoir Conditions  

NASA Astrophysics Data System (ADS)

The wetting properties of CO2-brine-rock systems will have a major impact on the management of CO2 injection processes. The wettability of a system controls the flow and trapping efficiency during the storage of CO2 in geological formations as well as the efficiency of enhanced oil recovery operations. Despite its utility in EOR and the continued development of CCS, little is currently known about the wetting properties of the CO2-brine system on reservoir rocks, and no investigations have been performed assessing the impact of these properties on CO2 flooding for CO2 storage or EOR. The wetting properties of multiphase fluid systems in porous media have major impacts on the multiphase flow properties such as the capillary pressure and relative permeability. While recent studies have shown CO2 to generally act as a non-wetting phase in siliciclastic rocks, some observations report that the contact angle varies with pressure, temperature and water salinity. Additionally, there is a wide range of reported contact angles for this system, from strongly to weakly water-wet. In the case of some minerals, intermediate wet contact angles have been observed. Uncertainty with regard to the wetting properties of CO2-brine systems is currently one of the remaining major unresolved issues with regards to reservoir management of CO2 storage. In this study, we make semi-dynamic capillary pressure measurements of supercritical CO2 and brine at reservoir conditions to observe shifts in the wetting properties. We utilize a novel core analysis technique recently developed by Pini et al in 2012 to evaluate a core-scale effective contact angle. Carbon dioxide is injected at constant flow rate into a core that is initially fully saturated with water, while maintaining a constant outlet pressure. In this scenario, the pressure drop across the core corresponds to the capillary pressure at the inlet face of the core. When compared with mercury intrusion capillary pressure measurements, core-scale effective contact angle can be determined. In addition to providing a quantitative measure of the core-averaged wetting properties, the technique allows for the observation of shifts in contact angle with changing conditions. We examine the wettability changes of the CO2-brine system in Berea sandstone with variations in reservoir conditions including supercritical, gaseous and liquid CO2injection. We evaluate wettability variation within a single rock with temperature, pressure, and salinity across a range of conditions relevant to subsurface CO2 storage. This study will include results of measurements in a Berea sandstone sample across a wide range of conditions representative of subsurface reservoirs suitable for CO2 storage (5-20 MPa, 25-90 oC, 0-5 mol kg-1). The measurement uses X-ray CT imaging in a state of the art core flooding laboratory designed to operate at high temperature, pressure, and concentrated brines.

Al-Menhali, Ali; Krevor, Samuel

2014-05-01

73

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

74

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

75

Capillary Electrophoresis of Proteins  

Microsoft Academic Search

1.1. Capillary Electrophoresis of Proteins Capillary electrophoresis (CE) is a separation technique that combines aspects of both gel electrophoresis and high performance liquid chromatography (HPLC). As is the case for gel electrophoresis, the separation in CE is based upon differential migration in an electrical field. Like HPLC, the detection of the migrating sample analytes may be monitored on-line or postcolumn\\/capillary

Mark Strege

76

Intranasal lobular capillary haemangioma.  

PubMed

Lobular capillary haemangioma (LCH) is a benign proliferation of capillaries with a characteristic lobular architecture on microscopy; it has an affinity for mucous membrane and skin of the head and neck. It is extremely rare in the nasal cavity. We present the case of a 45-year-old man who presented with epistaxis without any predisposing factors, which was diagnosed as lobular capillary haemangioma. PMID:25304675

Nayak, Dipak Ranjan; Bhandarkar, Ajay M; Shivamurthy, Archana; Joy, Jasmi

2014-01-01

77

TEACHING PHYSICS: Capillary effects  

NASA Astrophysics Data System (ADS)

We examine capillary tubes with a variable cross section, in which there is a column of fully wetting or fully non-wetting liquid. The direction in which the liquid moves when the tubes are placed horizontally is determined by means of Pascal's law. We promote the idea that the conical capillary tube is a hydraulic machine, whose two pistons are the liquid column's free surfaces, which have different radii. We propose a new way of demonstrating the described capillary effects by means of flat models of capillary tubes, constructed from glass plates. The demonstrations are presented in front of a large audience using an overhead projector.

Ivanov, Dragia; Petrova, Hristina

2000-07-01

78

Switch isotropic/anisotropic wettability via dual-scale rods  

NASA Astrophysics Data System (ADS)

It is the first time to demonstrate the comparison of isotropic/anisotropic wettability between dual-scale micro-nano-rods and single-scale micro-rods. Inspired by the natural structures of rice leaf, a series of micro-nano-rods and micro-rods with different geometric parameters were fabricated using micro-fabrication technology. Experimental measured apparent contact angles and advancing and receding contact angles from orthogonal orientations were characterized. The difference of contact angles from orthogonal orientation on dual-scale rods was much smaller than those on single-scale rods in both static and dynamic situation. It indicated that the dual-scale micro-nano-rods showed isotropic wettability, while single-scale micro-rods showed anisotropic wettability. The switch of isotropic/anisotropic wettability could be illustrated by different wetting state and contact line moving. It offers a facial way to switch isotropic/anisotropic wettability of the surface via dual-scale or single-scale structure.

He, Yang; Jiang, Chengyu; Wang, Shengkun; Ma, Zhibo; Yuan, Weizheng

2014-10-01

79

Motion of a drop on a horizontal solid surface with a wettability gradient  

NASA Astrophysics Data System (ADS)

The motion of drops of tetraethylene glycol in a wettability gradient present on a silicon surface is investigated experimentally and theoretically. The gradient was formed by exposing clean silicon surfaces to a source of dodecyltrichlorosilane vapor. The static contact angles were measured as a function of position and used to characterize the local wettability gradient. The Reynolds, capillary, and Bond numbers in the experiments were relatively small. The measured migration velocities of drops over a range of sizes demonstrated the complex nature of the variation of the velocity with position on the gradient surface in response to the changes in the driving force and the resistance to the motion. The results are organized and interpreted using a simple quasi-steady hydrodynamic model in which inertial effects and deformation due to gravity as well as motion are neglected so that the shape is approximated by a spherical cap. Two approaches are used to estimate the hydrodynamic resistance experienced by the drop. In the "wedge approximation" the drop is modeled as a collection of wedges; the drag on each wedge is calculated from a solution for Stokes flow. In the second approach, lubrication theory is employed while retaining the exact shape of the drop. A slip boundary condition is used in a region close to the contact line to relax the usual stress singularity. The results from the wedge approximation and lubrication theory are indistinguishable at contact angles ? 30. The theoretical model based on the wedge approximation describes the qualitative features of the shape of the curve of velocity versus position along the gradient surface. A detailed investigation of the remaining discrepancy does not support the hypothesis of a missing resistance due to either contact line dissipation or an underestimation of the hydrodynamic drag. Instead, it is concluded that a reduction in the driving force due to contact angle hysteresis is the most likely reason. The quantitative differences are accommodated by approximately accounting for the influence of hysteresis.

Moumen, Nadjoua

80

Rapid formation of superhydrophobic surfaces with fast response wettability transition.  

PubMed

We have developed a facile and time-saving method to prepare superhydrophobic surfaces on copper sheets. Various surface textures composed of Cu(OH)2 nanorod arrays and CuO microflowers/Cu(OH)2 nanorod arrays hierarchical structure were prepared by a simple solution-immersion process. After chemical modification with stearic acid, the wettability of the as-prepared surfaces was changed from superhydrophilicity to superhydrophobicity. The shortest processing time for fabricating a superhydrophobic surface was 1.5 min. Interestingly, the rapid wettability transition between superhydrophobicity and superhydrophilicity can be realized on the prepared surfaces with ease by the alternation of air-plasma treatment and stearic acid coating. It took just 2 min to complete the whole wettability transition. Additionally, the regeneration of the superhydrophobic surface is also considered regarding its application. PMID:21073178

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

2010-12-01

81

Wettability of a hydrophilic addition silicone impression material.  

PubMed

Silicone impression materials, long noted for their poor wettability, have typically demonstrated contact angles with water greater than 90 degrees. This study compared the wettability of a new hydrophilic addition silicone with that of other impression materials. Specimens from various viscosities of polyether, polysulfide, hydrophobic addition silicone, and hydrophilic addition silicone were formed against a smooth surface. The advancing contact angle of a saturated aqueous solution of CaSO4 on the impression materials was measured after 1 minute. Mean contact angles were calculated and results were analyzed by ANOVA and a multiple comparison of means procedure. Differences between pairs of contact angle means were found to be statistically significant except for the polyether-hydrophilic addition silicone pair. The wettability of the hydrophilic addition silicone impression material was found to be not significantly different from that of a polyether impression material. PMID:2654364

Pratten, D H; Craig, R G

1989-02-01

82

Capillary rheometry for thermosets  

NASA Technical Reports Server (NTRS)

Capillary rheometry is effectively used with thermosets. Most important is providing a uniform temperature in the barrel. This was successfully accomplished by using a circulating hot oil system. Standard capillary rheometry methods provide the dependence of thermoset apparent viscosity on shear rate, temperature and time. Such information is very useful in evaluating resin processability and in setting preliminary fabrication conditions.

Malguarnera, S. C.; Carroll, D. R.

1982-01-01

83

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

84

Process for making a wettable polyolefin battery separator  

Microsoft Academic Search

This invention is directed to a process for forming a wettable battery separator comprising a nonwoven mat of polyolefin fiber by forming a nonwoven mat of polyolefin fiber having a thickness in the range 10 to 40 mils and pore sizes less than 40 microns; contacting the mat with an aqueous solution of a water-soluble peroxy compound, e.g. hydrogen peroxide

J. A. Cogliano; N. S. Marans

1978-01-01

85

SURFACE CHARACTERIZATION OF CHEMICALLY MODIFIED WOOD: DYNAMIC WETTABILITY1  

E-print Network

SURFACE CHARACTERIZATION OF CHEMICALLY MODIFIED WOOD: DYNAMIC WETTABILITY1 John Z. Lu* Postdoctoral. Member of SWST. * Current address for John Z. Lu: Department of Wood Science and Engineering, 142 base-diameter spreading ratio (SR ) fitted the Boltzmann sigmoid model. Wetting behavior of Epolene G

86

Wettability and adhesion of marine and related adhesive proteins  

Microsoft Academic Search

Wettability on substrates with low and high surface energies of synthetic marine and related adhesive proteins has been investigated to evaluate the role of individual amino acids together with their sequences in marine adhesive proteins. The surface chemical analyses suggest that marine adhesives have a meaningful primary structure adhering to substrates. The polysaccharide chitosan adhered faster than marine adhesive proteins

Hiroyuki Yamamoto; Ayako Nishida; Kousaku Ohkawa

1999-01-01

87

Wettability Alteration with Silica Aerogel Nano-Dispersion  

Microsoft Academic Search

This work studies the wettability alteration using nanoporous silica aerogels for enhanced oil recovery. Water wet flat glass and outcrop sandstone are used for this aim. Modified silica aerogels are synthesized with cheap water glass as the precursor, and ambient pressure drying method. Sessile drop method was used to measure the contact angles. Sandstones with 0 contact angle changed to

H. Bargozin; J. S. Moghaddas

2012-01-01

88

A Numerical Investigation of Wettability Alteration during Immiscible CO2  

E-print Network

D Student ID#965189 Supervised by Dr. Sidqi A. Abu-Khamsin, Professor Dr. M. Enamul Hossain, Assistance as one of the controlling parameters of the remaining oil-in-place. The knowledge of wettability-phase immiscible simulation model was built numerically utilizing MATLAB program. This study showed

Hossain, M. Enamul

89

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. 19 figs.

Yeung, E.S.; Chang, H.T.; Fung, E.N.; Li, Q.; Lu, X.

1996-12-10

90

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

91

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

92

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. 19 figs.

Yeung, E.S.; Li, Q.; Lu, X.

1998-04-21

93

Autoclaving as a mean of modifying the soil wettability characteristics  

NASA Astrophysics Data System (ADS)

Studies of soil water repellency have often attempted to isolate its hydrological impact by comparing responses of wettable and water repellent soils. It is, however, almost impossible to identify natural wettable and water repellent soils that are otherwise fully comparable. Furthermore no established methodology exists that allows changing a soil from wettable to water repellent (or vice versa) without affecting its chemical composition. Approaches used for rendering wettable soil (or sands) water repellent involve coating particles with hydrophobic or commercial water repellent spray. Heating soil to temperatures >300 C has been used to eliminate existing water repellency from samples, but this can permanently alter the composition of organic matter. Here we report on a new technique for rendering wettable soil water repellent involving autoclaving. Autoclaving is commonly applied in medicine and biology for sterilization. It uses moist heat and pressure to destroy the bacteria, viruses and fungi. The same method has also been used in soil ecology studies for selective removal of certain micro-organisms. In our study, soils at various moisture contents were autoclaved in sealed bags for 1hr at 121C. The soils became water repellent and the degree of water repellency was found to be dependent on the original soil moisture content and the soil wettability remained unchanged even with further drying of the soil up to 105C. No changes in soil wettability were found after autoclaving very dry or wet soils. Only at certain intermediate water contents was the soil able to switch to a hydrophobic state. We suspect that the changes occurring during the autoclaving involve molecular orientation of hydrophobic and hydrophilic groups of soil organic matter, and moist heat and pressure cause the hydrophobic groups to be directed towards the outside of the soil particles which consequently repels water. Treatment of soil in this way presents a simple, inexpensive method of making a soil hydrophobic without changing its chemical composition. This has considerable potential for controlled experiments requiring both soils that differ only in terms of their degree of hydrophobicity.

Urbanek, Emilia; Bodi, Merche; Shakesby, Rick; Doerr, Stefan

2010-05-01

94

Wettability changes in polyether impression materials subjected to immersion disinfection  

PubMed Central

Background: Disinfection of impression materials prevents cross-contamination; however, the disinfectants may alter the wettability property. The purpose of this investigation was to evaluate the wettability changes of polyether impression material after immersing in four different chemical disinfectant solutions for a period of 10 min and 30 min, respectively. Materials and Methods: A total of 45 samples of polyether dental impression material (Impregum soft, 3MESPE, St. Paul, MN, USA) were randomly divided into nine groups with five specimens each. Each specimen was disc shaped, flat of 32 mm diameter and 3 mm thickness. The samples were immersed in four disinfectant solutions: 2% Glutaraldehyde, 5% sodium hypochlorite, 0.05% iodophor, and 5.25% phenol for 10 min and 30 min, respectively. The control was without disinfection. Wettability of the samples was assessed by measuring the contact angle by using the Telescopic Goniometer. Data were subjected to analysis of variance (Fisher's test) and Tukey's post hoc test for multiple comparisons at 5% level of significance. Results: The contact angle of 20.21 0.22 were recorded in the control samples. After 10 min, the samples that were immersed in 5% sodium hypochlorite and 5.25% phenol showed significant statistical increase in the contact angle as compared to the control (P < 0.001). After 30 min of disinfection, only the samples immersed in 0.05% iodophor showed there were no significant changes in the contact angle, whereas the other disinfectants significantly increased the contact angle and decreased the wettability of the polyether material. Conclusion: Within the limitations of the study, 2% glutaraldehyde proved safe for 10 min of immersion disinfection while 0.05% iodophor holds promise as an effective disinfectant without affecting the wettability of the material. PMID:24130593

Shetty, Shweta; Kamat, Giridhar; Shetty, Rajesh

2013-01-01

95

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

96

A tryptophan responsive fluorescent and wettable dual-signal switch.  

PubMed

A new fluorescent dianthracene calix[4]arene (C4DA) was designed and synthesized via coupling the fluorescent anthracene units and calix[4]arene units. Then it was used to form self-assembled monolayers (C4DA-SAMs) by the simple click reaction to give the first fluorescent and wettable dual-signal switch for tryptophan (Trp) on a micro- and nano-structured silicon surface. The switch for Trp on the C4DA functional surface was confirmed by contact angle (CA) measurements and fluorescent spectroscopy (FL). Furthermore, the wettability-responsive C4DA functional interface can be re-used for six cycles. The responsive switch can potentially be applied in many fields including nanodevices and intelligent microfluidic switching. PMID:24992098

Zhang, Xiaoyan; Li, Jing; Feng, Ningmei; Luo, Li; Dai, Zhen; Yang, Li; Tian, Demei; Li, Haibing

2014-09-21

97

Wettability Between Vehicle and Lead\\/Bismuth Oxide Glasses  

Microsoft Academic Search

Lead and bismuth glass systems have different wettability, which affects the mixture of the paste (vehicle and frits) and the burn-out of the vehicle within a thick film. This study examined the reaction between the vehicle (ethyl cellulose (EC) with ?-terpineol) and oxide glasses (PbO and Bi2O3 glasses). The contact angle with the vehicle on the Bi2O3 glass was found

Sangwook Lee; Dongsun Kim; Seongjin Hwang; Kyungjun Hong; Hyungsun Kim

2009-01-01

98

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. PMID:23553954

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

2014-01-01

99

Photoresponsive Wettability in Monolayer Films from Sinapinic Acid  

PubMed Central

Sinapinic acid is an interesting material because it is both antioxidant and antibacterial agent. In addition, when illuminated with ultraviolet light, it can exhibit the so-called photodimerization process. In this paper, we report on the investigation of monolayer films from 3,5-dimethoxy-4-hydroxycinnamic acid (sinapinic acid, SinA) deposited onto poly(allylamine hydrochloride), PAH, films. SinA monolayers were prepared by using the layer-by-layer (LbL) self-assembly technique. Adsorption kinetics curves were well fitted by a biexponential function suggesting that the adsorption process is determined by two mechanisms: nucleation and growth of aggregates. By using wetting contact angle analysis, we have found that SinA monolayers exhibit photoresponsive wettability under UV irradiation (365?nm); that is, wettability decreases with increasing UV irradiation time. The photoresponse of wettability was attributed to photodimerization process. This hypothesis was supported by the dependence of surface morphological structure and absorption on UV irradiation time. The mechanism found in the well-known transcinnamic acid crystals is used to explain the photodimerization process in SinA monolayers. PMID:24302879

Moura, Cleverson A. S.; Gomes, Douglas J. C.; de Souza, Nara C.; Silva, Josmary R.

2013-01-01

100

Poor Soil Wettability: Does moisture alter measurement results?  

NASA Astrophysics Data System (ADS)

Poor soil wettability is a global problem, creating challenges to agriculture by plant drought stress and to soil stability in natural environments. Events that lead to poor soil wettability are varied, including natural and manmade events such as forest fires, hot dry environments, poor soil management or the application of post-consumer materials. Even though options offered in the literature for amelioration of the symptoms of hydrophobicity greatly differ, the basic techniques used to identify hydrophobic soil have changed very little over the past half-century. Recently, however, scientists have begun to question what these traditional techniques are actually measuring. One of the areas of interest is the relationship of hydrophobicity to moisture content, also termed reversible or seasonal hydrophobicity. Many studies suggest that changes in the organic matter structure as it is exposed to soil moisture leads to a reduction of the surface energy of particle surfaces. This study further complements that work by investigating how testing methods and soil-sample treatment impact water sorption of hydrophobic media, so as to make it appear that the surface energy has changed. The understanding of this phenomenon can lead to improved techniques for testing of hydrophobicity soil and also for soil management in agricultural areas by understanding the impact of soil moisture regimes on wettability.

Dragila, M. I.; Woolverton, P.; Horneck, D.; Kleber, M.

2013-12-01

101

How Capillary Rafts Sink  

E-print Network

We present a fluid dynamics video showing how capillary rafts sink. Small objects trapped at an interface are very common in Nature (insects walking on water, ant rafts, bubbles or pollen at the water-air interface, membranes...) and are found in many multiphase industrial processes. Thanks to Archimedes principle we can easily predict whether an object sinks or floats. But what happens when several small particles are placed at an interface between two fluids. In this case surface tension also plays an important role. These particles self-assemble by capillarity and thus form what we call a "capillary raft". We show how such capillary rafts sink for varying sizes of particles and define how this parameter affects the sinking process.

Protiere, S; Aristoff, J; Stone, H

2010-01-01

102

Capillary condenser/evaporator  

NASA Technical Reports Server (NTRS)

A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

Valenzuela, Javier A. (Inventor)

2010-01-01

103

Capillary tube wetting induced by particles: towards armoured bubbles tailoring.  

PubMed

In this paper, we report on the strongly modified dynamics of a liquid finger pushed inside a capillary tube, when partially wettable particles are lying on the walls. Particles promote the appearance of new regimes and enable the tailored synthesis of bubbles encapsulated in a monolayer of particles (so-called "armoured bubbles"). This remarkable behavior arises due to the collection of particles at the air-liquid interface, which modify the global energy balance and stabilize the interface. Armoured-bubbles are of primary interest in industrial processes since they display increased stability, interfacial rigidity and can even sustain non-spherical shapes. This work opens perspective for a low cost bubbles-on-demand technology enabling the synthesis of armoured bubbles with specific sizes, shapes and composition. PMID:25271805

Zoueshtiagh, Farzam; Baudoin, Michael; Guerrin, David

2014-12-21

104

Investigating wettability alteration due to asphaltene precipitation: Imprints in surface multifractal characteristics  

NASA Astrophysics Data System (ADS)

In the present study, multifractality and its formalism were employed to investigate the surface characteristics of an asphaltene deposited heterogeneous solid surface. Wettability alteration of the solid surface was found to affect the multifractal characteristics of an asphaltene deposited heterogeneous surface. Multifractal spectra f( ?) show that the more oil wet the surface, the wider the spectrum, and the higher the fmax. The notable distinction between the multifractal spectra associated with different surface wettabilities can be used as a new aspect of wettability alteration.

Sayyad Amin, J.; Nikooee, E.; Ayatollahi, Sh.; Alamdari, A.

2010-08-01

105

Wettability of Silane-Treated Glass Slides as Determined from X-Ray Photoelectron Spectroscopy  

Microsoft Academic Search

The wettability and stability of silane-treated substrates are central in many processes of industrial and environmental interest. Here, we 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 we investigate the relationship between wettability and surface composition as determined from XPS. The adhesion behavior and contact

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

1995-01-01

106

Capillary nail refill test  

MedlinePLUS

Nail blanch test; Capillary refill time ... Remove colored nail polish before this test. ... the body by the blood (vascular) system. This test measures how well the vascular system works in your hands and feet -- the parts of your body that are farthest from the heart.

107

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

108

Investigations on surface wettability of ZnO nanowires using UV LEDs for biosensing applications  

NASA Astrophysics Data System (ADS)

ZnO is a biocompatible material suitable for biosensors and microfluidic devices. Nanowires of ZnO tend to show hydrophobic nature which decelerates the adhesion/adsorption of biomolecules on the surface. This paper discusses the investigations on tuning the wettability of ZnO nanowires using UV LEDs. The spectral effect of LED emission on ZnO nanowires wettability has been studied. Results indicate that UV LEDs offer an advanced control on tuning the wettability of ZnO nanowires. The spectral investigations have provided significant insight into the role of irradiating wavelength of light on the wettability.

Bhavsar, K.; Prabhu, R.; Pollard, P.

2014-08-01

109

Noise suppressing capillary separation system  

DOEpatents

A noise-suppressing capillary separation system for detecting the real-time presence or concentration of an analyte in a sample is provided. The system contains a capillary separation means through which the analyte is moved, a coherent light source that generates a beam which is split into a reference beam and a sample beam that irradiate the capillary, and a detector for detecting the reference beam and the sample beam light that transmits through the capillary. The laser beam is of a wavelength effective to be absorbed by a chromophore in the capillary. The system includes a noise suppressing system to improve performance and accuracy without signal averaging or multiple scans.

Yeung, Edward S. (Ames, IA); Xue, Yongjun (Norwich, NY)

1996-07-30

110

Wettability of supercritical carbon dioxide/water/quartz systems: simultaneous measurement of contact angle and interfacial tension at reservoir conditions.  

PubMed

Injection of carbon dioxide in deep saline aquifers is considered as a method of carbon sequestration. The efficiency of this process is dependent on the fluid-fluid and rock-fluid interactions inside the porous media. For instance, the final storage capacity and total amount of capillary-trapped CO2 inside an aquifer are affected by the interfacial tension between the fluids and the contact angle between the fluids and the rock mineral surface. A thorough study of these parameters and their variations with temperature and pressure will provide a better understanding of the carbon sequestration process and thus improve predictions of the sequestration efficiency. In this study, the controversial concept of wettability alteration of quartz surfaces in the presence of supercritical carbon dioxide (sc-CO2) was investigated. A novel apparatus for measuring interfacial tension and contact angle at high temperatures and pressures based on Axisymmetric Drop Shape Analysis with no-Apex (ADSA-NA) method was developed and validated with a simple system. Densities, interfacial tensions, and dynamic contact angles of CO2/water/quartz systems were determined for a wide range of pressures and temperatures relevant to geological sequestration of CO2 in the subcritical and supercritical states. Image analysis was performed with ADSA-NA method that allows the determination of both interfacial tensions and contact angles with high accuracy. The results show that supercritical CO2 alters the wettability of quartz surface toward less water-wet conditions compared to subcritical CO2. Also we observed an increase in the water advancing contact angles with increasing temperature indicating less water-wet quartz surfaces at higher temperatures. PMID:23627310

Saraji, Soheil; Goual, Lamia; Piri, Mohammad; Plancher, Henry

2013-06-11

111

[Multiple capillary aneurysms].  

PubMed

Recurrent eruptions of small, black nodules resembling metastases of malignant melanoma in a 64-year-old male patient with diabetes mellitus are reported. Clinically, the lesions seemed to be angiomas. Histological examination revealed capillary aneurysms. To date there has been no spontaneous regression. Sclerosing injections or compression therapy had no effect. Only total excision of lesions was successful. The etiology of the disease is unknown. The patient had diabetic retinopathy with increased plasma levels of cholesterol. PMID:3692856

Pokorn, M; Vanek, J; Pavcov, S

1987-09-01

112

Capillary isotachophoresis mass spectrometry  

SciTech Connect

The on-line combination of capillary isotachophoresis (CITP) with mass spectrometry is demonstrated for the first time. The CITP/MS interface is based upon electrospray ionization and is identical with that developed previously for capillary zone electrophoresis (CZE)/MS. Separations were conducted in untreated 100 ..mu..m i.d. fused silica capillaries having lengths of 0.6-2.5 m, at voltages up to 35 kV. The method involves elution of the leading electrolyte to the electrospray source followed by a sequence of separated analyte bands (if sufficient time is provided for development) and, finally, the trailing electrolyte. The CITP/MS was demonstrated to allow very high resolution separations of quaternary phosphonium ions and other ionic substances having very small differences in electrophoretic mobilities. Nearly ideal band shapes are obtained in most separations despite the presence of electroosmotic flow. The potential for application to very dilute sample solutions is demonstrated by detection of analytes having 10/sup /minus/9/ M concentrations, with signal to noise ratios of approximately 10/sup 2/ for some components, which as at least 2 orders of magnitude better than CZE/MS. CITP/MS appears to be an attractive complement to CZE/MS for dilute (low ionic strength) solutions since much greater sample sizes can be addressed without loss of efficiency.

Udseth, H.R.; Loo, J.A.; Smith, R.D.

1989-02-01

113

Rapid and inexpensive quantification of the combined polar components of surface wettability: Application to biofouling  

Microsoft Academic Search

A technique is presented (the SHM method) that rapidly and inexpensively quantifies surface wettability using aqueous methanol solutions. The SHM method, which can be performed using basic, generally available laboratory equipment, yields a single value that is strongly correlated with the combined polar (acid?base) components of surface wettability. In laboratory studies employing silanised glass surfaces, larval settlement rates of the

D. J. Gerhart; D. Rittschof; I. R. Hooper; K. Eisenman; A. E. Meyer; R. E. Baier; C. Young

1992-01-01

114

Wettability of the casing and electrolyte leakage in airtight nickel-cadmium storage batteries  

Microsoft Academic Search

The results of studying the wettability of 08KP steel used for manufacture of storage battery casings, with an alkali solution at various potentials of the metal's surface are presented. It is shown that greatest wettability, and consequently, an increased tendency toward electrolyte leakage along the storage battery casing is observed when the casing is connected electrically to the negative block

R. V. Boldin

1974-01-01

115

Forest Service -U.S. Department of Agriculture Soil Wettability and Wetting Agents...  

E-print Network

Forest Service - U.S. Department of Agriculture Soil Wettability and Wetting Agents... U.S. FOREST, John, Jr. 1967. Soil wettability and wetting agents . . . our current knowledge of the problem-43) Soils that resist wetting are a widespread phenomenon on chaparral areas of southern California

Standiford, Richard B.

116

Wettability of kraft pulps-effect of surface composition and oxygen plasma treatment  

Microsoft Academic Search

Wettability and ESCA studies have been carried out using unextracted and extracted kraft pulps with different amounts of lignin. The effect of oxygen plasma treatment was investigated. The wettability was studied by placing a drop of water on a sheet made from the pulp and following the decrease in drop volume and apparent contact angle with time. The first reading

Gran Strm; Gilbert Carlsson

1992-01-01

117

Understanding the relationship between wettability and dissolution of solid dispersion.  

PubMed

Improved wettability has been ascribed to one of the important mechanisms for enhanced dissolution of solid dispersions. But its relationship with dissolution has not been closely studied to date. In this study, solid dispersion of simvastatin (SV) and polyvinylpyrrolidone (PVP) was prepared without and with sodium dodecyl sulfate (SDS) incorporated, respectively. The dissolution, contact angle and water absorption rate of these solid dispersions were measured to elucidate the relationship between wettability and dissolution. An abrupt increase of dissolution was observed when PVP amount exceeded a critical value. Contact angle was decreased with increasing of PVP amount. And the dissolution efficiency of the solid dispersion was increased with the decreasing of the contact angle, which was divided by a critical angle of 40.8 into two linear parts. The result was validated in the dissolution of SDS incorporated solid dispersions. Contact angle correlated well with water absorption rate. A critical water absorption rate, with value of 0.535 ?L/min, was also observed for the transition of dissolution efficiency. In conclusion, both contact angle and water absorption rate are good indicators for dissolution transition of solid dispersion, which show great potential in formula screening of solid dispersion. PMID:24524825

Lu, Yi; Tang, Ning; Lian, Ruyue; Qi, Jianping; Wu, Wei

2014-04-25

118

Morphology modulating the wettability of a diamond film.  

PubMed

Control of the wetting property of diamond surface has been a challenge because of its maximal hardness and good chemical inertness. In this work, the micro/nanoarray structures etched into diamond film surfaces by a maskless plasma method are shown to fix a surface's wettability characteristics, and this means that the change in morphology is able to modulate the wettability of a diamond film from weakly hydrophilic to either superhydrophilic or superhydrophobic. It can be seen that the etched diamond surface with a mushroom-shaped array is superhydrophobic following the Cassie mode, whereas the etched surface with nanocone arrays is superhydrophilic in accordance with the hemiwicking mechnism. In addition, the difference in cone densities of superhydrophilic nanocone surfaces has a significant effect on water spreading, which is mainly derived from different driving forces. This low-cost and convenient means of altering the wetting properties of diamond surfaces can be further applied to underlying wetting phenomena and expand the applications of diamond in various fields. PMID:25280079

Tian, Shibing; Sun, Weijie; Hu, Zhaosheng; Quan, Baogang; Xia, Xiaoxiang; Li, Yunlong; Han, Dong; Li, Junjie; Gu, Changzhi

2014-10-28

119

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

120

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

Microsoft Academic Search

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

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

2007-01-01

121

Capillary reference half-cell  

DOEpatents

The present invention is a reference half-cell electrode wherein intermingling of test fluid with reference fluid does not affect the performance of the reference half-cell over a long time. This intermingling reference half-cell may be used as a single or double junction submersible or surface reference electrode. The intermingling reference half-cell relies on a capillary tube having a first end open to reference fluid and a second end open to test fluid wherein the small diameter of the capillary tube limits free motion of fluid within the capillary to diffusion. The electrode is placed near the first end of the capillary in contact with the reference fluid. The method of operation of the present invention begins with filling the capillary tube with a reference solution. After closing the first end of the capillary, the capillary tube may be fully submerged or partially submerged with the second open end inserted into test fluid. Since the electrode is placed near the first end of the capillary, and since the test fluid may intermingle with the reference fluid through the second open end only by diffusion, this intermingling capillary reference half-cell provides a stable voltage potential for long time periods.

Hall, Stephen H. (Kennewick, WA)

1996-01-01

122

Capillary flow in sacrificially etched nanochannels  

PubMed Central

Planar nanochannels are fabricated using sacrificial etching technology with sacrificial cores consisting of aluminum, chromium, and germanium, with heights ranging from 18 to 98 nm. Transient filling via capillary action is compared against the Washburn equation [E. W. Washburn, Phys. Rev. 17, 273 (1921)], showing experimental filling speeds significantly lower than classical continuum theory predicts. Departure from theory is expressed in terms of a varying dynamic contact angle, reaching values as high as 83 in channels with heights of 18 nm. The dynamic contact angle varies significantly from the macroscopic contact angle and increases with decreasing channel dimensions. PMID:21772934

Hamblin, Mark N.; Hawkins, Aaron R.; Murray, Dallin; Maynes, Daniel; Lee, Milton L.; Woolley, Adam T.; Tolley, H. Dennis

2011-01-01

123

STUDIES ON BLOOD CAPILLARIES  

PubMed Central

The wall of the blood capillaries of skeletal muscles (diaphragm, tongue, hind legs) and myocardium of the rat, guinea pig, and hamster consists of three consecutive layers or tunics: the endothelium (inner layer), the basement membrane with its associated pericytes (middle layer), and the adventitia (outer layer). The flattened cells of the endothelium have a characteristic, large population of cytoplasmic vesicles which, within the attenuated periphery of the cells, may attain a maximum frequency of 120/2 of cell front and occupy ?18% of the cytoplasmic volume; these values decrease as the cells thicken toward the perikaryon. The vesicles are 650750 A in over-all diameter and are bounded by typical unit membranes. They occur as single units or are fused to form short chains of two to three vesicles. Each configuration may lie entirely within the cytoplasm or open onto the cell surface. In the latter case, the unit membrane of the vesicle is continuous, layer by layer, with the plasmalemma. Chains of vesicles opening simultaneously on both the blood and tissue fronts of the endothelial tunic have not been observed either in sections or in a tridimensional reconstruction of a sector of endothelial cell cytoplasm. Adjacent endothelial cells are closely apposed to one another and appear to be joined over a large part of their margins, possibly over their entire perimeter, by narrow belts of membrane fusion (zonulae occludentes). Except for tongue capillaries, patent intercellular gaps are rare or absent. The middle layer is formed by a continuous basement membrane (?500 A thick) and by pericytes which lie in between leaflets of this membrane. The tips of the pericyte pseudopodia penetrate through the inner leaflet of the basement membrane and join the endothelium in maculae occludentes. The adventitia is a discontinuous layer comprising cellular (macrophages, fibroblasts, mast cells) and extracellular (fibrils, amorphous matrix) elements. The same general type of construction appears to be used along the entire length of the capillary. PMID:5656394

Bruns, Romaine R.; Palade, George E.

1968-01-01

124

Dynamic wettability properties of a soft contact lens hydrogel.  

PubMed

The wettability of poly[2-hydroxyethyl methacrylate-co-methacrylic acid] (pHEMA-MAA) soft contact lenses was investigated in the absence and presence of block copolymer surfactants and lysozyme using the sessile drop method. The advancing dynamic contact angles (Thetaw/a) values are reported for water as a function of sequential wetting and drying cycles. The Thetaw/a values for the pHEMA-MAA in the absence of surfactant and lysozyme increased from approximately 20 degrees to 100 degrees as the number of cycles increased from two to ten, and they were independent of the pHEMA-MAA bulk water content. The change from the highly hydrophilic to hydrophobic pHEMA-MAA surface could not be reversed using the sequential wetting and drying cycles even under repeated exposures to saline solution. The effect of block copolymer surfactants with different molecular weights (MW) and hydrophilic-lipophilic balance (HLB) values on the pHEMA-MAA wettability were also studied. Low Theta(w/a) values were observed for pHEMA-MAA hydrogels that were treated with T1304 (MW 10500, HLB 14) and T904 (MW 6700, HLB 15). The surface tension data indicated that these surfactants were incompletely desorbed from the pHEMA-MAA and that the rate of desorption was slow in the timescale of the cycling experiments. Comparatively, poor wettability was observed for pHEMA-MAA surfaces presoaked in T304 (MW 1650, HLB 16) and T1107 (MW 15000, HLB 24) as Thetaw/a values greater than 90 degrees were measured for these surfactants. The surface tension data indicated that the rate of desorption of T304 and T1107 from the pHEMA-MAA was rapid and that they had a low affinity to the pHEMA-MAA. High contact angles were observed for the pHEMA-MAA hydrogels treated with lysozyme and also for the T1107 presoaked pHEMA-MAA that was also treated with lysozyme. Zero wetting angles throughout the sequential cycling were observed for the T1304 pre-treated pHEMA-MAA that had been treated with lysozyme. These results suggested that the adsorbed lysozyme on the pHEMA-MAA hydrogel had no significant influence on its wetting properties when the hydrogel was pre-treated with T1304. PMID:15620833

Ketelson, Howard A; Meadows, David L; Stone, Ralph P

2005-01-15

125

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

126

Capillary suspensions: Particle networks formed through the capillary force  

E-print Network

The addition of small amounts of a secondary fluid to a suspension can, through the attractive capillary force, lead to particle bridging and network formation. The capillary bridging phenomenon can be used to stabilize particle suspensions and precisely tune their rheological properties. This effect can even occur when the secondary fluid wets the particles less well than the bulk fluid. These materials, so-called capillary suspensions, have been the subject of recent research studying the mechanism for network formation, the properties of these suspensions, and how the material properties can be modified. Recent work in colloidal clusters is summarized and the relationship to capillary suspensions is discussed. Capillary suspensions can also be used as a pathway for new material design and some of these applications are highlighted. Results obtained to date are summarized and central questions that remain to be answered are proposed in this review.

Erin Koos

2014-10-21

127

Methods and preliminary measurement results of liquid Li wettability.  

PubMed

A test of lithium wettability was performed in high vacuum (< 3 10(-4) Pa). High magnification images of Li droplets on stainless steel substrates were produced and processed using the MATLAB() program to obtain clear image edge points. In contrast to the more standard "?/2" or polynomial fitting methods, ellipse fitting of the complete Li droplet shape resulted in reliable contact angle measurements over a wide range of contact angles. Using the ellipse fitting method, it was observed that the contact angle of a liquid Li droplet on a stainless steel substrate gradually decreased with increasing substrate temperature. The critical wetting temperature of liquid Li on stainless steel was observed to be about 290?C. PMID:24593360

Zuo, G Z; Hu, J S; Ren, J; Sun, Z; Yang, Q X; Li, J G; Zakharov, L E; Mansfield, D K

2014-02-01

128

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

129

Viscous drop collisions on surfaces of varying wettability  

NASA Astrophysics Data System (ADS)

We present an experimental study of increasingly viscous acetone rich and Newtonian equivalent liquid drops colliding on surfaces of varying wettability. This class of liquids applies directly to spray coating processes in pharmaceutical industries. The results from this study will elucidate the physics in a regime where resisting viscous forces and the restoring forces of capillarity are balanced, Oh 1. Early spreading dynamics ?=Ut/D 1 indicate negligible dependence on contact angles while longer times demonstrate deviations from Tanner's law, Dt^1/10. We will compare our results with recent theory to demonstrate the feasibility of modelling complex rheology spreading characteristics over short and long time scales. Preliminary results indicate an intermediate spreading regime following the inertial phase where the diameter, Dt^n with 1/7 < n < 1/5.

Bolleddula, Daniel; Berchielli, Al; Aliseda, Alberto

2010-11-01

130

Local wettability tuning with laser ablation redeposits on PDMS  

NASA Astrophysics Data System (ADS)

In this paper, we present a method to locally control the wettability behavior of PDMS surfaces by excimer laser ablation. In the ablation process, a micrometer scale roughness is formed in the irradiated regions while a nanometer scale roughness is formed by the redeposits surrounding the irradiated regions. The increase in surface roughness results in a change of the wettability behavior of the PDMS surface. By using a hexagonal pattern and tuning the patterning pitch, two different wetting behaviors were realized. A pitch smaller than 300 ?m resulted in a superhydrophobic surface with an advancing contact angle of ?adv = 165 and a receding contact angle of ?rec = 160. A pitch between 300 and 500 ?m resulted in a sticky superhydrophobic surface with ?adv = 120-150 and ?rec = 80. The contact angle hysteresis for the latter was larger than for untreated PDMS resulting in very sticky surfaces with high sliding angles. This gives the method great versatility since the two wetting behaviors are very different. By combining both behaviors, local surface features like pinning sites, non-wetting sites, barriers and guides can all be fabricated by a single method. As an application demonstrator of the method, we show that drops can be caught and released depending on size and tilting angle by creating slippery surfaces with sticky barriers. Additionally, the method is ideal for rapid prototyping as it consist of only a single step. It is a direct write method requiring no lithographic mask. Also the process works in ambient atmosphere, so it can be used for temperature or pressure sensitive applications.

van Pelt, Stijn; Frijns, Arjan; Mandamparambil, Rajesh; den Toonder, Jaap

2014-06-01

131

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

132

Capillary optics for radiation focusing  

SciTech Connect

Capillary lens technology may ultimately bring benefits to neutron and x-ray-based science like conventional lenses with visible light. Although the technology is not yet 10 years old, these lenses have already had a significant impact in engineering, science, and medicine. Capillary lenses are advantageous when it is desirable to increase the radiation flux at a location without regard to its angular divergence. PNNL has worked to improve the technology in several ways. A single, optimally tapered capillary was manufactured, which allows intensity gains of a factor of 270 for an initially parallel, incident x-ray beam. Feasibility of constructing neutron lenses using {sup 58}Ni (particularly effective at reflecting neutrons) has been explored. Three applications for capillary optics have been identified and studied: neutron telescope, Gandolphi x-ray diffractometry, and neutron radiotherapy. A brief guide is given for determining which potential applications are likely to be helped by capillary optics.

Peurrung, A.J.; Reeder, P.L.; Bliss, M.; Craig, R.A.; Lepel, E.A.; Stromswold, D.C.; Stoffels, J.; Sunberg, D.S.; Tenny, H.

1996-11-01

133

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

134

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

2011-12-01

135

A Microfluidic Device for Mixing of Capillary-Driven Liquids  

NASA Astrophysics Data System (ADS)

In this paper, a novel microfluidic device for mixing liquids is described. Main feature of this device is that the liquids are passively pumped through microchannels only by capillary action, and therefore no external power is required for the pumping. This feature brings extremely simple hardware setup and easy operation. In this device, a pneumatically-actuated, normally-closed microvalve regulates capillary-driven flow. The device has been fabricated with polydimethylsiloxane (PDMS) elastomer, and tested using fluorescent dye and fluorescent particle solutions. A simple method for controlling the mixing ratio is also demonstrated.

Hosokawa, Kazuo; Maeda, Mizuo

136

Surface charges of oxides and wettability: Application to TiO2-SiO2 composite films  

NASA Astrophysics Data System (ADS)

The super-hydrophilicity which can exist at the interface between oxides and aqueous solutions is able to sustain industrial and domestic applications. Several experimental results obtained on TiO2-SiO2 composite thin films via a sol-gel route have confirmed a natural and persistent super hydrophilicity under standard atmosphere. This property can be easily photo-regenerated after a long aging period in ambient atmosphere using a short UV illumination. The electrochemical double layer which classically exists between oxide surfaces and aqueous solution is unfavorable to high wettability properties of ideal flat surfaces. The present study indicates how the surface rugosity and the disjoining pressure caused by surface charges are able to explain the stability of a prewetting film. This film can withstand to vaporization in a weakly under saturated atmosphere, having a protective action despite a carbon contamination brought by standard atmosphere.

Joud, J.-C.; Houmard, M.; Berthom, G.

2013-12-01

137

Steady Capillary Driven Flow  

NASA Technical Reports Server (NTRS)

A steady capillary driven flow is developed for a liquid index in a circular tube which is partially coated with a surface modifier to produce a discontinuous wetting condition from one side of the tube to the other. The bulk flow is novel in that it is truly steady, and controlled solely by the physics associated with dynamic wetting. The influence of gravity on the flow is minimized through the use of small diameter tubes approximately O(1 mm) tested horizontally in a laboratory and larger tubes approximately O(10 mm) tested in the low gravity environment of a drop tower. Average steady velocities are predicted and compared against a large experimental data set which includes the effects of tube dimensions and fluid properties. The sensitivity of the velocity to surface cleanliness is dramatic and the advantages of experimentation in a microgravity environment are discussed.

Weislogel, Mark M.

1996-01-01

138

Benign sinonasal capillary haemangioma.  

PubMed

Haemangiomas are benign fibrovascular tumours relatively that are common in the head and neck, where 60% of them occur Among the various categories of haemangiomas, lobular capillary haemangiomas (LCH) occur frequently on the skin, lips, buccal mucosa, tongue and gingiva. However, they are vanishingly rare in the paranasal sinuses. The imaging features of LCH are non-specific. The histological characteristics of LCH can also make diagnosis difficult as sometimes resemble highly vascular malignant tumours. This leads to the false preoperative diagnosis of suspected malignancy in many cases, which places the patient under unnecessary distress and anxiety. We present a case of LCH appearing as a suspicious nasal lesion of the lateral nasal wall with unilateral nasal obstruction, necrotic centre and epistaxis. The tumour was excised endoscopically in one operation including endoscopic medial maxillectomy. Further education about this lesion is deemed important as preoperative embolisation may be needed for a safe operation. PMID:25287393

Stubbs, Darren; Poulios, Aristotelis; Khalil, Hisham

2014-01-01

139

Capillary interconnect device  

DOEpatents

A manifold for connecting external capillaries to the inlet and/or outlet ports of a microfluidic device for high pressure applications is provided. The fluid connector for coupling at least one fluid conduit to a corresponding port of a substrate that includes: (i) a manifold comprising one or more channels extending therethrough wherein each channel is at least partially threaded, (ii) one or more threaded ferrules each defining a bore extending therethrough with each ferrule supporting a fluid conduit wherein each ferrule is threaded into a channel of the manifold, (iii) a substrate having one or more ports on its upper surface wherein the substrate is positioned below the manifold so that the one or more ports is aligned with the one or more channels of the manifold, and (iv) means for applying an axial compressive force to the substrate to couple the one or more ports of the substrate to a corresponding proximal end of a fluid conduit.

Renzi, Ronald F. (Tracy, CA)

2007-12-25

140

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

141

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

E-print Network

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, ...

O'Hanley, Harry

142

Surfactant Screening to Alter the Wettability and Aid in Acidizing Carbonate Formations  

E-print Network

Surfactant flooding in carbonate matrix acidizing treatment has been widely used for changing the wettability of the rock and to achieve low IFT values. Optimizing the type of surfactant and concentration for the specific oil field is very important...

Yadhalli Shivaprasad, Arun Kumar

2013-02-26

143

Annual Logging Symposium, June 26-29, 2005 INFLUENCE OF OIL SATURATION AND WETTABILITY  

E-print Network

-Verdín, The University of Texas at Austin Copyright 2005, held jointly by the Society of Petrophysicists and Well Log, non-Archie behavior, frequently takes place in rocks exhibiting oil wettability or irregular pore

Torres-Verdín, Carlos

144

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 Ti6Al4V 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

145

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

146

Capillary electrophoresis of gene mutation.  

PubMed

This chapter illustrates the usefulness of capillary electrophoresis (CE) for the detection of gene mutation, i.e., point mutation, methylation, and microsatellite analysis. In order to provide a general description of the main results and challenges in the field, some relevant applications and reviews on CE of gene mutation are tabulated. Furthermore, some detailed experimental procedures are shown. Several CE methods of gene mutation detection were developed including the following: (1) single-strand conformation polymorphism with capillary electrophoresis; (2) SNaPshot analysis; (3) constant denaturant capillary electrophoresis; (4) microsatellite analysis; and (5) methylation analysis. PMID:18392579

Xu, Guowang; Shi, Xianzhe; Zhao, Chunxia; Yuan, Kailong; Weng, Qianfeng; Gao, Peng; Tian, Jing

2008-01-01

147

Decay of capillary wave turbulence  

E-print Network

We report on the observation of freely decaying capillary wave turbulence on the surface of a fluid. The capillary wave turbulence spectrum decay is found to be self-similar in time with the same power law exponent than the one found in the stationary regime, in agreement with weak turbulence predictions. The amplitude of all Fourier modes are found to decrease exponentially with time at the same damping rate. The longest wavelengths involved in the system are shown to be damped by viscous surface boundary layer. These long waves play the role of an energy source during the decay that sustains nonlinear interactions to keep capillary waves in a wave turbulent state.

Luc Deike; Michal Berhanu; Eric Falcon

2012-07-13

148

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

149

Capillary end effects in coreflood calculations  

Microsoft Academic Search

Capillary end effects in coreflood experiments, in some cases, can significantly influence the computation of end-point relative permeabilities and final saturation levels. Because capillary end effects arise from capillarity, these corrections for relative permeability and saturation can be quantified if the capillary pressure curve is known a priori. Based on Darcy's law and the relative permeabilitycapillary pressure relationships, we present

David D. Huang; Matt M. Honarpour

1998-01-01

150

A review on the wettability of dental implant surfaces I: theoretical and experimental aspects.  

PubMed

The surface wettability of biomaterials determines the biological cascade of events at the biomaterial/host interface. Wettability is modulated by surface characteristics, such as surface chemistry and surface topography. However, the design of current implant surfaces focuses mainly on specific micro- and nanotopographical features, and is still far from predicting the concomitant wetting behavior. There is an increasing interest in understanding the wetting mechanisms of implant surfaces and the role of wettability in the biological response at the implant/bone or implant/soft tissue interface. Fundamental knowledge related to the influence of surface roughness (i.e. a quantification of surface topography) on titanium and titanium alloy surface wettability, and the different associated wetting regimes, can improve our understanding of the role of wettability of rough implant surfaces on the biological outcome. Such an approach has been applied to biomaterial surfaces only in a limited way. Focusing on titanium dental and orthopaedic implants, the present study reviews the current knowledge on the wettability of biomaterial surfaces, encompassing basic and applied aspects that include measurement techniques, thermodynamic aspects of wetting and models predicting topographical and roughness effects on the wetting behavior. PMID:24590162

Rupp, Frank; Gittens, Rolando A; Scheideler, Lutz; Marmur, Abraham; Boyan, Barbara D; Schwartz, Zvi; Geis-Gerstorfer, Jrgen

2014-07-01

151

Retardation of ice growth in glass capillaries: Measurement of the critical capillary radius Zhihong Liu,1  

E-print Network

Retardation of ice growth in glass capillaries: Measurement of the critical capillary radius films. The velocity dependence of the ice front propagation in glass capillaries with radii of 87.5 m­1, was obtained, below which the ice growth inside the capillaries was retarded. This critical capillary radius

Wan, Richard G.

152

Sequential perfusion of skeletal muscle capillaries.  

PubMed

Rats were injected intraarterially with a fluorescent dye that binds to capillary endothelium, thereby labeling any capillary through which it has passed. After 10, 15, or 30 sec of circulation of the dye blood flow was interrupted, the gastrocnemius was frozen, and the density and distribution of labeled capillaries were measured in transverse sections of the central portion of the medial head. These tissue sections were then counterstained by the myosin ATPase method for capillaries to mark all capillaries. After 10 sec, 45% of all capillaries were labeled and after 15 sec, 59% of all capillaries were labeled. Thirty seconds after injection, all capillaries were labeled with the fluorescent dye. In all three time intervals, the distributions of labeled capillaries were ordered, suggesting that there is a tissue-level control mechanism for regulating capillary perfusion to maintain relatively short maximal oxygen diffusion distances. PMID:2935714

Kayar, S R; Banchero, N

1985-11-01

153

AUTOMATED, TEMPERATURE-CALIBRATED MEASUREMENT OF CAPILLARY REFILL TIME APPLYING FORCE TO THE FINGER SOFTWARE AND OPERATION  

E-print Network

refill time. The capillary refill test, used medically to test for shock and/or dehydration, is currently the need for a standardized capillary refill test, our device, the D1GIT, performs three main functions refill time test, incorporating and facilitating all of the actions of a human doctor. SUMMARY Advisor

Carpick, Robert W.

154

Adequacy of Capillary Lead Specimens.  

National Technical Information Service (NTIS)

In response to the increased demand for reliable alternatives to venous lead testing, the Centers for Disease Control has called for increased research into using capillary methodologies. In the past, there have been problems with this procedure, primaril...

N. H. Johnson

1995-01-01

155

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

156

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

157

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

158

Development of functional polymer surfaces with controlled wettability.  

PubMed

There is a demand for surfaces with new functional properties in almost all industrial branches. During the next few years, research input will be required for the development of coatings exhibiting an easy-to-clean or self-cleaning ability, switchability so that they can act as sensors/actuators, and defined tribological/mechanical properties and long-term stability. To achieve such behavior, the development of new advanced functional coatings that exhibit the proper chemistry and surface structure is necessary. In this Feature Article, we provide a review of the research activities in our laboratory on the development of functional and, especially, reversibly switchable polymer surfaces where the emphasis is on controlling their wettability. We will first discuss the fabrication of superhydrophobic surfaces by hierarchically micro- and nanostructuring a substrate surface with an ultrafast laser followed by appropriate hydrophobization. Then, we will summarize the development of surfaces that can alter their wetting behavior in response to changes in external stimuli such as humidity and light illumination. Finally, we will present our investigations on utilizing responsive (organic) coatings on hierarchically roughened substrates for the development of surfaces, which would be able to switch reversibly from superhydrophilic to superhydrophobic and water-repellent in response to an external stimulus (in this case, pH). PMID:23789943

Anastasiadis, Spiros H

2013-07-30

159

Manipulated wettability of a superhydrophobic quartz crystal microbalance through electrowetting  

NASA Astrophysics Data System (ADS)

The liquid phase response of quartz crystal microbalances (QCMs) with a thin coating (9 m) of epoxy resin with and without a carbon nanoparticles top layer is reported. The nanoparticles convert the epoxy surface to a superhydrophobic one with a high static contact angle (151-155) and low contact angle hysteresis (1-3.7) where droplets of water are in the suspended Cassie-Baxter state. The frequency decrease of the fully immersed QCM with the superhydrophobic surface is less than with only epoxy layer, thus indicating a decoupling of the QCM response. A wettability transition to a liquid penetrating into the surface roughness state (for droplets a high contact angle hysteresis Wenzel state) was triggered using a molarity-of-ethanol droplet test (MED) and electrowetting; the MED approach caused some surface damage. The electrowetting-induced transition caused a frequency decrease of 739 Hz at a critical voltage of 100 V compared to the QCM in air. This critical voltage correlates to a contact angle decrease of 26 and a high contact angle hysteresis state in droplet experiments. These experiments provide a proof-of-concept that QCMs can be used to sense wetting state transitions and not only mass attachments or changes in viscosity-density products of liquids.

Esmeryan, K. D.; McHale, G.; Trabi, C. L.; Geraldi, N. R.; Newton, M. I.

2013-08-01

160

Wettability of naturally aged silicone and EPDM composite insulators  

SciTech Connect

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 surfaces are larger than the contact angles of the RTV silicone rubber coating and of the EPDM rubber insulator surfaces, especially when the surfaces are aged. When the insulators were exposed to corona discharges, the contact angles of the silicone rubber insulators are reduced but after the exposure they recover with time. The contact angles of the EPDM rubber insulators, however, after the exposure, continue to reduce. When exposed to artificial saline pollution, the silicone rubber insulators show a limited recovery of their contact angles with time, while, when exposed to corona discharge, they show a recovery of the contact angle after the exposure. The time for recovery is dependent on the exposure time to the corona discharges.

Gubanski, S.M. (Royal Inst. of Tech., Stockholm (Sweden)); Vlastos, A.E. (Chalmers Univ. of Tech., Goeteborg (Sweden))

1990-07-01

161

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

162

Wettability of biomimetic thermally grown aluminum oxide coatings.  

PubMed

In this paper, wettability behavior of a rough but intrinsically hydrophilic oxide ceramic, formed via simple thermal oxidation of a commercial metallic alloy in laboratory air, has been analyzed. Drop shape analysis (DSA) revealed static water contact angles for the rough ceramic surfaces up to 128 (greater than for Teflon). We propose the high apparent contact angles to be a result of surface roughening via the morphological changes of the oxide scale with oxidation conditions. The surface morphological changes occurring during the growth of the oxide film resulted in the formation of vertical platelets that ably shifted the wetting behavior from a Wenzel to an unstable Cassie-Baxter state. The platelet morphology of the ceramic resembles the structure of epicuticular waxes on certain species of superhydrophobic leaves. Moreover, surface textures for very short oxidation times were also found to increase hydrophilicity in the scale and reduce the contact angle by imparting a Wenzel state. Various characterization techniques (XRD, XPS, and SEM) were performed in order to detect the crystallographic phases in the scales, analyze carbon content and determine the morphology of the oxide layer. Morphological features of the oxide platelets were quantified and platelet width, spacing and height were found to correlate well with the apparent contact angle trend as a function of oxidation time. PMID:21252413

Samad, Jadid E; Nychka, John A

2011-03-01

163

Tailoring surface hydrophilicity of porous electrospun nanofibers to enhance capillary and push-pull effects for moisture wicking.  

PubMed

In this article, liquid moisture transport behaviors of dual-layer electrospun nanofibrous mats are reported for the first time. The dual-layer mats consist of a thick layer of hydrophilic polyacrylonitrile (PAN) nanofibers with a thin layer of hydrophobic polystyrene (PS) nanofibers with and without interpenetrating nanopores, respectively. The mats are coated with polydopamine (PDOPA) to different extents to tailor the water wettability of the PS layer. It is found that with a large quantity of nanochannels, the porous PS nanofibers exhibit a stronger capillary effect than the solid PS nanofibers. The capillary motion in the porous PS nanofibers can be further enhanced by slight surface modification with PDOPA while retaining the large hydrophobicity difference between the two layers, inducing a strong push-pull effect to transport water from the PS to the PAN layer. PMID:25020135

Dong, Yuliang; Kong, Junhua; Phua, Si Lei; Zhao, Chenyang; Thomas, Noreen L; Lu, Xuehong

2014-08-27

164

Inverse problem of capillary filling.  

PubMed

The inverse problem of capillary filling, as defined in this work, consists in determining the capillary radius profile from experimental data of the meniscus position l as a function of time t. This problem is central in diverse applications, such as the characterization of nanopore arrays or the design of passive transport in microfluidics; it is mathematically ill posed and has multiple solutions; i.e., capillaries with different geometries may produce the same imbibition kinematics. Here a suitable approach is proposed to solve this problem, which is based on measuring the imbibition kinematics in both tube directions. Capillary filling experiments to validate the calculation were made in a wide range of length scales: glass capillaries with a radius of around 150???m and anodized alumina membranes with a pores radius of around 30??nm were used. The proposed method was successful in identifying the radius profile in both systems. Fundamental aspects also emerge in this study, notably the fact that the l(t)?t1/2 kinematics (Lucas-Washburn relation) is not exclusive of uniform cross-sectional capillaries. PMID:24745427

Elizalde, Emanuel; Urteaga, Ral; Koropecki, Roberto R; Berli, Claudio L A

2014-04-01

165

Inverse Problem of Capillary Filling  

NASA Astrophysics Data System (ADS)

The inverse problem of capillary filling, as defined in this work, consists in determining the capillary radius profile from experimental data of the meniscus position l as a function of time t. This problem is central in diverse applications, such as the characterization of nanopore arrays or the design of passive transport in microfluidics; it is mathematically ill posed and has multiple solutions; i.e., capillaries with different geometries may produce the same imbibition kinematics. Here a suitable approach is proposed to solve this problem, which is based on measuring the imbibition kinematics in both tube directions. Capillary filling experiments to validate the calculation were made in a wide range of length scales: glass capillaries with a radius of around 150 ?m and anodized alumina membranes with a pores radius of around 30 nm were used. The proposed method was successful in identifying the radius profile in both systems. Fundamental aspects also emerge in this study, notably the fact that the l(t)?t1/2 kinematics (Lucas-Washburn relation) is not exclusive of uniform cross-sectional capillaries.

Elizalde, Emanuel; Urteaga, Ral; Koropecki, Roberto R.; Berli, Claudio L. A.

2014-04-01

166

Gravity-Capillary Lumps  

NASA Astrophysics Data System (ADS)

In dispersive wave systems, it is known that 1-D plane solitary waves can bifurcate from linear sinusoidal wavetrains at particular wave numbers k = k0 where the phase speed c(k) happens to be an extremum (dc/dk| _0=0) and equals the group speed c_g(k_0). Two distinct possibilities thus arise: either the extremum occurs in the long-wave limit (k_0=0) and, as in shallow water, the bifurcating solitary waves are of the KdV type; or k0 ne 0 and the solitary waves are in the form of packets, described by the NLS equation to leading order, as for gravity-capillary waves in deep water. Here it is pointed out that an entirely analogous scenario is valid for the genesis of 2-D solitary waves or `lumps'. Lumps also may bifurcate at extrema of the phase speed and do so when 1-D solitary waves happen to be unstable to transverse perturbations; moreover, they have algebraically decaying tails and are either of the KPI type (e.g. in shallow water in the presence of strong surface tension) or of the wave packet type (e.g. in deep water) and are described by an elliptic-elliptic Davey-Stewartson equation system to leading order. Examples of steady lump profiles are presented and their dynamics is discussed.

Akylas, Triantaphyllos R.; Kim, Boguk

2004-11-01

167

Structure-Function Studies of Blood and Air Capillaries in Chicken Lung Using 3D Electron Microscopy  

PubMed Central

Avian pulmonary capillaries differ from those of mammals in three important ways. The blood-gas barrier is much thinner, it is more uniform in thickness, and the capillaries are far more rigid when their transmural pressure is altered. The thinness of the barrier is surprising because it predisposes the capillaries to stress failure. A possible mechanism for these differences is that avian pulmonary capillaries, unlike mammalian, are supported from the outside by air capillaries, but the details of the support are poorly understood. To clarify this we studied the blood and air capillaries in chicken lung using transmission electron microscopy (EM) and two relatively new techniques that allow 3D visualization: electron tomography and serial block-face scanning EM. These studies show that the pulmonary capillaries are flanked by epithelial bridges composed of two extremely thin epithelial cells with large surface areas. The junctions of the bridges with the capillary walls show thickening of the epithelial cells and an accumulation of extracellular matrix. Collapse of the pulmonary capillaries when the pressure outside them is increased is apparently prevented by the guy wire-like action of the epithelial bridges. The enlarged junctions between the bridges and the walls could provide a mechanism that limits the hoop stress in the capillary walls when the pressure inside them is increased. The support of the pulmonary capillaries may also be explained by an interdependence mechanism whereby the capillaries are linked to a rigid assemblage of air capillaries. These EM studies show the supporting structures in greater detail than has previously been possible, particularly in 3D, and they allow a more complete analysis of the mechanical forces affecting avian pulmonary capillaries. PMID:20038456

West, John B.; Fu, Zhenxing; Deerinck, Thomas J.; Mackey, Mason R.; Obayashi, James T.; Ellisman, Mark H.

2010-01-01

168

New concept for coal wettability evalution and modulation. Final report 1 January 1992--30 September 1995  

SciTech Connect

The study was concerned with a new concept for coal surface wettability evaluation and modulation. The objectives of the work were to study the fundamental surface chemistry for the evaluation of the surface wettability and floatability of coal nd minerals. A new separation strategy will contribute to the advanced selective separation of coal and pyrite. The theories of wettability and floatability of coal and mineral are discussed. A new concept of kinetic wettability, kinetic floatability, and kinetic collectability has been explored. In addition, their evaluation and correlation have been established. Some practical applications to improve the advanced selective flotation of coal and pyrite have been suggested.

Hu, Weibai; Zou, Yuzhi; Wang, Qingping

1995-12-31

169

Electrohydrostatics of Capillary Switches  

NASA Astrophysics Data System (ADS)

A pair of supported droplets that are coupled via a liquid filled cylindrical hole of radius R in a plate is referred to as a capillary switch (CS). A CS is known to exhibit two stable equilibrium states when the combined volume of the top and the bottom droplets is greater than 4/3 ?R^3. This fact is exploited in various applications, including optical lenses and adhesion, where the main challenge is to come up with a method to"toggle" the CS between the two stable states that is reliable, is energy efficient, and has fast response. The use of an electric field to achieve this purpose is explored here through simulations in which the axisymmetric shapes and stability of a CS are determined as a function of applied field strength. In the simulations, the liquid is taken to be perfectly conducting and the ambient fluid on either side of the plate outside the CS to be a passive gas. An axial electric field is applied either on one or both sides of a grounded plate. The equilibrium shapes of the CS and the electric potential in the surrounding gas are governed by an augmented Young-Laplace equation and the Laplace equation, respectively. These equations are solved computationally using the Galerkin finite element method. Results are shown as plots of dimensionless volume difference between the two droplets against electrical Bond number (ratio of electric to surface tension force). These phase diagrams are used to infer whether an electric field represents an effective means for toggling a CS.

Sambath, Krishnaraj; Basaran, Osman

2010-11-01

170

Cardiovascular Actions of Insulin  

Microsoft Academic Search

Insulin has important vascular actions to stimulate produc- tion of nitric oxide from endothelium. This leads to capillary recruitment, vasodilation, increased blood flow, and subse- quent augmentation of glucose disposal in classical insulin target tissues (e.g., skeletal muscle). Phosphatidylinositol 3-kinase-dependent insulin-signaling pathways regulating endothelial production of nitric oxide share striking parallels with metabolic insulin-signaling pathways. Distinct MAPK- dependent insulin-signaling pathways

Ranganath Muniyappa; Monica Montagnani; Kwang Kon Koh; Michael J. Quon

2007-01-01

171

Capillary filling under electro-osmotic effects in the presence of electromagneto-hydrodynamic effects.  

PubMed

We report various regimes of capillary filling dynamics under electromagneto-hydrodynamic interactions, in the presence of electrical double layer effects. Our chosen configuration considers an axial electric field and transverse magnetic field acting on an electrolyte. We demonstrate that for positive interfacial potential, the movement of the capillary front resembles capillary rise in a vertical channel under the action of gravity. We also evaluate the time taken by the capillary front to reach the final equilibrium position for positive interfacial potential and show that the presence of a transverse magnetic field delays the time of travel of the liquid front, thereby sustaining the capillary motion for a longer time. Our scaling estimates reveal that the initial linear regime starts, as well as ends, much earlier in the presence of electrical and magnetic body forces, as compared to the corresponding transients observed under pure surface tension driven flow. We further obtain a long time solution for the capillary imbibition for positive interfacial potential, and derive a scaling estimate of the capillary stopping time as a function of the applied magnetic field and an intrinsic length scale delineating electromechanical influences of the electrical double layer. Our findings are likely to offer alternative strategies of controlling dynamical features of capillary imbibition, by modulating the interplay between electromagnetic interactions, electrical double layer phenomena, and hydrodynamics over interfacial scales. PMID:25019889

Desai, Nikhil; Ghosh, Uddipta; Chakraborty, Suman

2014-06-01

172

Capillary filling under electro-osmotic effects in the presence of electromagneto-hydrodynamic effects  

NASA Astrophysics Data System (ADS)

We report various regimes of capillary filling dynamics under electromagneto-hydrodynamic interactions, in the presence of electrical double layer effects. Our chosen configuration considers an axial electric field and transverse magnetic field acting on an electrolyte. We demonstrate that for positive interfacial potential, the movement of the capillary front resembles capillary rise in a vertical channel under the action of gravity. We also evaluate the time taken by the capillary front to reach the final equilibrium position for positive interfacial potential and show that the presence of a transverse magnetic field delays the time of travel of the liquid front, thereby sustaining the capillary motion for a longer time. Our scaling estimates reveal that the initial linear regime starts, as well as ends, much earlier in the presence of electrical and magnetic body forces, as compared to the corresponding transients observed under pure surface tension driven flow. We further obtain a long time solution for the capillary imbibition for positive interfacial potential, and derive a scaling estimate of the capillary stopping time as a function of the applied magnetic field and an intrinsic length scale delineating electromechanical influences of the electrical double layer. Our findings are likely to offer alternative strategies of controlling dynamical features of capillary imbibition, by modulating the interplay between electromagnetic interactions, electrical double layer phenomena, and hydrodynamics over interfacial scales.

Desai, Nikhil; Ghosh, Uddipta; Chakraborty, Suman

2014-06-01

173

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. Crude Oil/Brine/Solid Interactions The interactions between crude oils, brines, and solid surfaces have been studied using a variety of core materials as well as in two-dimensional micromodels of interconnecting pores and throats. In the work reported this quarter, these same interactions have been applied to create mixed-wet conditions in a very simple model porous material, namely square glass tubes which have the advantage of permitting dual occupancy by both wetting and nonwetting phases simultaneously. The interactions between crude oil samples from Prudhoe Bay have been studied on a variety of surfaces. Figure 1 outlines the regions of stable and unstable brine compositions with A-93, a sample from Prudhoe Bay, and glass surfaces. A brine with pH 8 and 1 M concentration of NaCl produces a stable water film between glass and A-93 crude oil. If the brine has pH 4 and 0.01M NaCl, thin films of water are unstable and oil contacts the glass. Between these extremes is a wide band of brine compositions for which film stability is conditional.

Buckley, J.S.

1997-10-01

174

Treatment process for capillary hemangioma  

PubMed Central

Background Hemangiomas, usually, present at the first few months of life and are the most common benign tumor in children. There are various therapeutic methods for hemangioma. Capillary hemangioma is a type of hemangiomas. The steps of treatment of a child with capillary hemangioma in Taleghani Hospital of Gorgan, Iran, are reported. Case report In this report, it is described an 18-month-old child with capillary hemangioma on the right side of face. She was presented to the hematologic clinic of Taleghani Hospital of Gorgan. Three drugs, including prednisolon, propranolol and interferon alpha-2b (IFN-?-2b), were used for treating this patient. At the end of treatment, good results were obtained. After that, laser therapy was performed for fading the lesions. Conclusion Prescription of drug was our first choice for treating capillary hemangioma and it had a positive result without any complications. We used propranolol and IFN-?-2b for treating capillary hemangioma because of their better effect on this patient.

Mirbehbahani, NB; Rashidbaghan, A

2014-01-01

175

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

176

Time dependent wettability of graphite upon ambient exposure: The role of water adsorption  

NASA Astrophysics Data System (ADS)

We report the temporal evolution of the wettability of highly ordered pyrolytic graphite (HOPG) exposed to environmental conditions. Macroscopic wettability is investigated by static and dynamic contact angles (SCA and DCA) obtaining values comparable to the ones presented in the literature. SCA increases from 68 to 90 during the first hour of exposure after cleaving, whereas DCA is characterized by longer-scale (24 h) time evolution. We interpret these results in light of Fourier transform infrared spectroscopy, which indicates that the evolution of the HOPG wettability is due to adsorption of molecules from the surrounding atmosphere. This hypothesis is further confirmed by nanoscopic observations obtained by atomic force microscope (AFM)-based force spectroscopy, which monitor the evolution of surface properties with a spatial resolution superior to macroscopic experiments. Moreover, we observe that the results of macro- and nanoscale measurements evolve in similar fashion with time and we propose a quantitative correlation between SCA and AFM measurements. Our results suggest that the cause of the transition in the wettability of HOPG is due to the adsorption of hydrocarbon contaminations and water molecules from the environment. This is corroborated by annealing the HOPG is vacuum conditions at 150, allowing the desorption of molecules on the surface, and thus re-establishing the initial macro and nano surface properties. Our findings can be used in the interpretation of the wettability of more complicated systems derived from HOPG (i.e., graphene).

Amadei, Carlo A.; Lai, Chia-Yun; Heskes, Daan; Chiesa, Matteo

2014-08-01

177

Non-Aqueous Capillary Electrophoresis  

NASA Astrophysics Data System (ADS)

Non-aqueous capillary electrophoresis and capillary electrochromatography are special variants of these techniques. Here, organic solvents or their mixtures with or without dissolved electrolytes are used as separation buffer or mobile phase, respectively. The most important features of non-aqueous systems are: better solubility of more hydrophobic ionic substances (many natural products) than in water, much less current and Joule heating allows for using highly concentrated buffers and/or larger capillary internal diameters, polar interactions are enhanced in organic solvents which is often highly advantageous in chiral separation systems. This chapter presents most frequently used solvents, their properties, as well as shows pH* scale which is often used in non-aqueous systems.

Szumski, Micha?; Buszewski, Bogus?aw

178

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

179

Soft liquid phase adsorption for fabrication of organic semiconductor films on wettability patterned surfaces.  

PubMed

We report a soft liquid-phase adsorption (SLPA) technique for the fabrication of organic semiconductor films on wettability-patterned substrates using toluene/water emulsions. Wettabilitypatterned substrates were obtained by the UV-ozone treatment of self-assembled monolayers of silane coupling agents on glass plates using a metal mask. Organic semiconductor polymer films were formed selectively on the hydrophobic part of the wettability-patterned substrates. The thickness of the films fabricated by the SLPA technique is significantly larger than that of the films fabricated by dip-coating and spin-coating techniques. The film thickness can be controlled by adjusting the volume ratio of toluene to water, immersion angle, immersion temperature, and immersion time. The SLPA technique allows for the direct production of organic semiconductor films on wettability-patterned substrates with minimized material consumption and reduced number of fabrication steps. PMID:25296571

Watanabe, Satoshi; Akiyoshi, Yuri; Matsumoto, Mutsuyoshi

2014-10-30

180

In situ investigation of ice formation on surfaces with representative wettability  

NASA Astrophysics Data System (ADS)

In this work, we have prepared a series of samples with five representative surface wettabilities: i.e. superhydrophilic, hydrophilic, critical, hydrophobic and superhydrophobic. These samples were in situ observed the freezing process of water droplets on clean and artificially contaminated surfaces to investigate the relationship between surface wettability and ice formation. Ice accretion was also tested by spraying supercooled water to samples at different horizontal inclination angles (HIA). Surface topography was proved to be essential to the icing through heterogeneous nucleation. However, the correlation between surface wettability and ice formation was not observed. Finally, we found that the superhydrophobic surface clearly exhibited reduced ice accumulation in the initial stage of ice formation associated with the lower sliding angle (SA) of water droplets.

Yin, Long; Xia, Qiang; Xue, Jian; Yang, Shuqing; Wang, Qingjun; Chen, Qingmin

2010-09-01

181

Capillary Network Model: Capillary Power and Effective Permeability  

E-print Network

A simple model of two-phase flow in porous media is presented. A connection is made to statistical mechanics by applying capillary power as a constraint. Stochastic sampling is then used to test the validity of this approach. Good agreement is found between stochastic sampling and time stepping for flow-rates above a transition value.

Grva, Morten

2012-01-01

182

Capillary Network Model: Capillary Power and Effective Permeability  

E-print Network

A simple model of two-phase flow in porous media is presented. A connection is made to statistical mechanics by applying capillary power as a constraint. Stochastic sampling is then used to test the validity of this approach. Good agreement is found between stochastic sampling and time stepping for flow-rates above a transition value.

Morten Grva

2012-03-16

183

Influence of biochar and terra preta substrates on wettability and erodibility of soils  

NASA Astrophysics Data System (ADS)

Biochar (BC) and terra preta substrates (TPS) have recently been promoted as soil amendments suitable for soil stabilization, soil amelioration and long-term carbon sequestration. BC is a carbon-enriched substance produced by thermal decomposition of organic material. TPS is composed of liquid and solid organic matter, including BC, altered by acid-lactic fermentation. Their effect on wettability, soil erodibility and nutrient discharge through overland flow was studied by laboratory experiments. At water contents between 0 and 100% BC is water repellent, while TPS changes from a wettable into a repellent state. The 5 and 10 vol % mixtures of BC and 10 and 20 vol% mixtures of TPS with sand remain mainly wettable during drying but repellency maxima are shifted to higher water contents with respect to pure sand and are mainly of subcritical nature. The runoff response was dominated by infiltration properties of the substrates rather than their wettability.Only one mixtures (20% TPS) produced more runoff than sandy-loamy soil on a 15% slope at an intensity of 25 mmh-1. The 10% BC decreased runoff by up to 40%. At higher rainfall intensities (45 and 55 mmh-1) the 10% TPS7 was up to 35% less erodible than 10% BC. Despite the TPS containing more nutrients, nutrient discharge varied between types of nutrients, slopes, rainfall intensities and mixtures. The application of a 1 cm layer onto the soil surface instead of 10% mixtures is not recommended due to high nutrient concentrations in the runoff and the wettability of pure substrates. The usage of 10% BC in lowland areas with low frequency and low-intensity precipitation and 10% TPS7 in areas with higher rainfall intensities appears to be appropriate and commendable according to current results. However, together with reversibility of repellency, it needs to undergo further examination in the field under different environmental and land use conditions Key words: biochar, terra preta substrate, wettability, erodibility, nutrient discharge

Smetanova, A.; Dotterweich, M.; Diehl, D.; Ulrich, U.; Fohrer, N.

2012-04-01

184

Joule heating and determination of temperature in capillary electrophoresis and capillary electrochromatography columns  

Microsoft Academic Search

This article reviews the progress that has taken place in the past decade on the topic of estimation of Joule heating and temperature inside an open or packed capillary in electro-driven separation techniques of capillary electrophoresis (CE) and capillary electrochromatography (CEC), respectively. Developments in theoretical modeling of the heat transfer in the capillary systems have focused on attempts to apply

Anurag S. Rathore

2004-01-01

185

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 11020C, hydrophilic patterns are written over an originally hydrophobic polymer surface. By further heating to 19020C, 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

186

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

187

The Flow of Gases through Capillaries  

Microsoft Academic Search

The flows of hydrogen, helium, nitrogen, ethylene, argon and carbon dioxide through capillaries have been measured at room temperature in the region of transition between molecular and viscous flow for capillary walls of polymethylmethacrylate and gold. Large numbers of capillaries were used in parallel, each from 2 to 3 mm long and about 0\\\\cdot 08 mm in diameter. The minima

J. A. W. Huggill

1952-01-01

188

The temperature sensor based on capillary waveguide  

NASA Astrophysics Data System (ADS)

The paper presents temperature sensor based on double layer capillary waveguide. The basics of mathematical calculation of guiding light through double layer capillary are presented. The fabrication process and properties of double layer capillary waveguide are showed. The practical application for monitoring of high-temperature industrial oil is shown. The paper contains the obtained characteristic of the temperature sensor.

Miluski, Piotr; Dorosz, Dominik

2008-01-01

189

Capillary electrophoresis for drug analysis  

NASA Astrophysics Data System (ADS)

Capillary electrophoresis (CE) is a high resolution separation technique which is amenable to a wide variety of solutes, including compounds which are thermally degradable, non-volatile and highly polar, and is therefore well suited for drug analysis. Techniques which have been used in our laboratory include electrokinetic chromatography (ECC), free zone electrophoresis (CZE) and capillary electrochromatography (CEC). ECC, which uses a charged run buffer additive which migrates counter to osmotic flow, is excellent for many applications, including, drug screening and analyses of heroin, cocaine and methamphetamine samples. ECC approaches include the use of micelles and charged cyclodextrins, which allow for the separation of complex mixtures. Simultaneous separation of acidic, neutral and basic solutes and the resolution of optical isomers and positional isomers are possible. CZE has been used for the analysis of small ions (cations and anions) in heroin exhibits. For the ECC and CZE experiments performed in our laboratory, uncoated capillaries were used. In contrast, CEC uses capillaries packed with high performance liquid chromatography stationary phases, and offers both high peak capacities and unique selectivities. Applications include the analysis of cannabinoids and drug screening. Although CE suffers from limited concentration sensitivity, it is still applicable to trace analysis of drug samples, especially when using injection techniques such as stacking, or detection schemes such as laser induced fluorescence and extended pathlength UV.

Lurie, Ira S.

1999-02-01

190

Capillary electrochromatography with macroporous particles  

Microsoft Academic Search

The performance of macro-porous particles in capillary electrochromatography is studied. Three reversed-phase stationary phases with pore diameters between 500 and 4000 have been tested for separation efficiency and mobile phase velocity. With these stationary phases, a large portion of the total flow appears to be through the pores of particles, thereby increasing the separation efficiency through a further

Remco Stol; Wim Th. Kok; Hans Poppe

1999-01-01

191

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

192

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

193

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

2012-04-17

194

Capillary filling dynamics of viscoelastic fluids  

NASA Astrophysics Data System (ADS)

We consider the filling of a capillary by a viscoelastic fluid described by the Phan-Thien-Tanner (PTT) constitutive behavior. By considering both vertical capillary filling and horizontal capillary filling, we demarcate the role played by gravity and fluid rheology towards long-time oscillations in the capillary penetration depth. We also consider the isothermal filling of the capillary for a closed channel and thus bring out the fundamental differences in the nature of capillary filling for PTT and Newtonian fluids for closed channels in comparison to open channels. Through a scaling analysis, we highlight a distinct viscoelastic regime in the horizontal capillary filling which is in contrast to the Washburn scaling seen in the case of Newtonian fluids. Such an analysis with a very general constitutive behavior is therefore expected to shed light on many areas of microfluidics which focus on biofluids that are often well described by the PTT constitutive behavior.

Bandopadhyay, Aditya; Ghosh, Uddipta; Chakraborty, Suman

2014-05-01

195

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

196

Wettability and Adhesion of Synthetic Marine Adhesive Proteins and Related Model Compounds  

Microsoft Academic Search

Wettability on substrates with low and high surface energies using synthetic marine adhesive proteins and related model compounds containing Lys has been investigated to evaluate the role of individual amino acids together with the sequences in marine adhesive proteins. Among sequential polypeptides, those containing Gly and Lys exhibited higher work of adhesion in four different substrates. The important role of

HIROYUKI YAMAMOTO; TAKAHIRO OGAWA; KOUSAKU OHKAWA

1995-01-01

197

Wettability and adhesion studies of plasma-treated plastic substrates for gelatin holograms  

Microsoft Academic Search

The feasibility study of using polycarbonate and poly(methyl methacrylate) substrates treated with the oxygen plasma for dichromated gelatin holograms is reported. The contact angles of water on both treated and untreated substrates were measured to indicate the wettability of substrate surfaces. An appreciable increase in adhesion between the dichromated gelatin film and the polycarbonate substrate after the oxygen plasma treatment

B. L. Chow; D. J. Whittle

1988-01-01

198

Annual Logging Symposium, May 14-18, 2011 QUANTIFYING WETTABILITY ALTERATION DURING OIL-BASE  

E-print Network

models the processes of mud-filtrate invasion and ensuing wettability alterations once emulsifiers the degree and type of alteration are governed by the pore- volume concentration of emulsifier in OBMF within contact with OBMF emulsifiers. The reduction of irreducible water saturation causes a portion of connate

Torres-Verdín, Carlos

199

Sulfur-rich carbon cryogels for supercapacitors with improved conductivity and wettability  

E-print Network

Sulfur-rich carbon cryogels for supercapacitors with improved conductivity and wettability Yao Zhou,abc Stephanie L. Candelaria,b Qian Liu,a Yunxia Huang,d Evan Uchakerb and Guozhong CaO*b Sulfur-rich carbon. Pyrolysis of sulfur-rich carbon at higher temperatures resulted in decreased electrical conductivity, which

Cao, Guozhong

200

INFLUENCE OF WETTABILITY ON LIQUID WATER TRANSPORT IN GAS DIFFUSION LAYER OF PROTON EXCHANGE MEMBRANE FUEL  

E-print Network

INFLUENCE OF WETTABILITY ON LIQUID WATER TRANSPORT IN GAS DIFFUSION LAYER OF PROTON EXCHANGE to 3D systems, notably from binarised images of GDLs obtained by X ray microtomography. 1. INTRODUCTION that a detailed understanding of liquid water transport in the gas diffusion layer (GDL) is necessary

Paris-Sud XI, Université de

201

Cold plasma treatment of polypropylene surface: a study on wettability and adhesion  

Microsoft Academic Search

The increasing use of polymeric materials in high technological fields, such as automotive, has forced the need to overcome some of their limitations by means of innovative processing. In the automobile industry a complex and critical process is used in order to enhance both wettability and adhesive properties of polypropylene bumper surfaces. Cold plasma treatment represents an efficient, clean and

Luigi Carrino; Giovanni Moroni; Wilma Polini

2002-01-01

202

Effects of surface wettability on nucleate pool boiling heat transfer for surfactant solutions  

Microsoft Academic Search

Experiments for pool boiling of deionised water and acetone with different surfactant, 95% sodium dodecyl sulfate (SDS), Triton X-100 and octadecylamine, have been conducted under atmospheric pressure to investigate the effect of surface wettability. The boiling curves for different concentrations of surfactant solution on both smooth and roughened surfaces were obtained. The results show that the addition of surfactant can

D. S Wen; B. X Wang

2002-01-01

203

Bioinspired conical copper wire with gradient wettability for continuous and efficient fog collection.  

PubMed

Inspired by the efficient fog collection on cactus spines, conical copper wires with gradient wettability are fabricated through gradient electrochemical corrosion and subsequent gradient chemical modification. These dual-gradient copper wires' fog-collection ability is demonstrated to be higher than that of conical copper wires with pure hydrophobic surfaces or pure hydrophilic surfaces, and the underlying mechanism is also analyzed. PMID:24038211

Ju, Jie; Xiao, Kai; Yao, Xi; Bai, Hao; Jiang, Lei

2013-11-01

204

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

PubMed

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 the corona from a knife-type electrode whose power increases gradually along the sample length. The PE surfaces oxidized gradually with the increasing corona power, and the wettability gradient was created on the surfaces as evidenced by the measurement of water contact angles, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. The wettability gradient surfaces prepared were used to investigate the interaction of different types of cells (Chinese hamster ovary, fibroblast, and endothelial cells) as well as serum proteins in terms of the surface hydrophilicity/hydrophobicity of polymeric materials. The cells adhered and grown on the gradient surface along the sample length were counted and observed by scanning electron microscopy. It was observed that the cells were adhered, spread, and grown more onto the positions with moderate hydrophilicity of the wettability gradient surface than onto the more hydrophobic or hydrophilic positions. The maximum adhesion and growth of the cells appeared at around water contact angles of 55 degrees, regardless of the cell types used. This result seems closely related to the serum protein adsorption on the surfaces; the serum proteins were also adsorbed more onto the positions with moderate hydrophilicity of the wettability gradient surface. Copyright 1998 Academic Press. PMID:9735195

Lee; Khang; Lee; Lee

1998-09-15

205

Wettability and Oil Recovery by Imbibition and Viscous Displacement from Fractured and Heterogeneous Carbonates  

SciTech Connect

About one-half of U.S. oil reserves are held in carbonate formations. The remaining oil in carbonate reservoirs is regarded as the major domestic target for improved oil recovery. Carbonate reservoirs are often fractured and have great complexity even at the core scale. Formation evaluation and prediction is often subject to great uncertainty. This study addresses quantification of crude oil/brine/rock interactions and the impact of reservoir heterogeneity on oil recovery by spontaneous imbibition and viscous displacement from pore to field scale. Wettability-alteration characteristics of crude oils were measured at calcite and dolomite surfaces and related to the properties of the crude oils through asphaltene content, acid and base numbers, and refractive index. Oil recovery was investigated for a selection of limestones and dolomites that cover over three orders of magnitude in permeability and a factor of four variation in porosity. Wettability control was achieved by adsorption from crude oils obtained from producing carbonate reservoirs. The induced wettability states were compared with those measured for reservoir cores. The prepared cores were used to investigate oil recovery by spontaneous imbibition and viscous displacement. The results of imbibition tests were used in wettability characterization and to develop mass transfer functions for application in reservoir simulation of fractured carbonates. Studies of viscous displacement in carbonates focused on the unexpected but repeatedly observed sensitivity of oil recovery to injection rate. The main variables were pore structure, mobility ratio, and wettability. The potential for improved oil recovery from rate-sensitive carbonate reservoirs by increased injection pressure, increased injectivity, decreased well spacing or reduction of interfacial tension was evaluated.

Norman R. Morrow; Jill Buckley

2006-04-01

206

Treelike networks accelerating capillary flow  

NASA Astrophysics Data System (ADS)

Transport in treelike networks has received wide attention in natural systems, oil recovery, microelectronic cooling systems, and textiles. Existing studies are focused on transport behaviors under a constant potential difference (including pressure, temperature, and voltage) in a steady state [B. Yu and B. Li, Phys. Rev. E 73, 066302 (2006), 10.1103/PhysRevE.73.066302; J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007), 10.1103/PhysRevE.75.056301]. However, dynamic (time-dependent) transport in such systems has rarely been concerned. In this work, we theoretically investigate the dynamics of capillary flow in treelike networks and design the distribution of radius and length of local branches for the fastest capillary flow. It is demonstrated that capillary flow in the optimized tree networks is faster than in traditional parallel tube nets under fixed constraints. As well, the flow time of the liquid is found to increase approximately linearly with penetration distance, which differs from Washburn's classic description that flow time increases as the square of penetration distance in a uniform tube.

Shou, Dahua; Ye, Lin; Fan, Jintu

2014-05-01

207

A molecular dynamics study of the force between planar substrates due to capillary bridges.  

PubMed

Molecular dynamics simulations are used to study capillary liquid bridges between two planar substrates and the origin, strength and range of the resulting force between them. Pairwise interactions are described by the Lennard-Jones potential. Surface wettability is tuned by varying the fluid-substrate well depth interaction parameter. The force between the substrates due to a bridge of liquid is estimated by different methods including non-equilibrium simulations of moving substrates connected by liquid bridges and macroscopic balance of forces. The latter involves knowledge of liquid-vapor interfacial free energy, curvature radii, radius of wetted area and contact angle at the triple-phase contact line. All these physical quantities are estimated from equilibrium simulations. The force is attractive when the substrates are solvophilic or moderately solvophobic; and thus for cavities surrounded by the same liquid the force is attractive even when the substrates are moderately solvophilic. Two threshold values for the fluid-substrate potential interaction parameter can be identified; one for which the effective interaction between substrates due to liquid bridges changes from repulsive to attractive and another for which the capillary bridge becomes mechanically unstable and breaks into droplets. PMID:24863777

Saavedra, Jorge H; Rozas, Roberto E; Toledo, Pedro G

2014-07-15

208

Effect of dynamic contact angle in a volume of fluid (VOF) model for a microfluidic capillary flow.  

PubMed

We perform three-dimensional numerical and experimental study of the dynamic contact angle using volume of fluid (VOF) method applied to microfluidic channels with integrated pillars. Initially, we evaluated different dynamic contact angle models (hydrodynamic, molecular kinetic and empirical) for capillary filling of a two-dimensional microchannel using analytical formulation. Further, the models which require a minimum prescription of adjustable parameters are only used for the study of capillary filling of microchannels with integrated pillars using different working fluids such as DI water, ethanol and isopropyl alcohol. Different microchannel geometry with varying diameter/height/spacing were studied for circular pillars. Effect of square pillars and changing the overall number of pillars on the capillary phenomena were also simulated. Our study demonstrated that the dynamic contact angle models modifies the transient response of the meniscus displacement and also the observed trends are model specific for the various microchannel geometries and working fluids. However, the different models have minimal effect on the meniscus profile. Different inlet boundary conditions were applied to observe the effect of grid resolution selected for numerical study on the capillary filling time. A grid dependent dynamic contact angle model which incorporates effective slip in the model was also used to observe the grid convergence of the numerical results. The grid independence was shown to improve marginally by applying the grid dependent dynamic contact angle model. Further we did numerical experiments of capillary filling considering variable surface wettability on the top and bottom walls of the microchannel with alternate hydrophilic-hydrophobic patterns. The meniscus front pinning was noticed for a high wetting contrast between the patterns. Non uniform streamline patterns indicated mixing of the fluid when using patterned walls. Such a microfluidic device with variable surface properties with integrated pillars may be useful for carrying out biological operations that often require effective separation and mixing of the fluids. PMID:19732904

Ashish Saha, Auro; Mitra, Sushanta K

2009-11-15

209

Microfluidic PMMA interfaces for rectangular glass capillaries  

NASA Astrophysics Data System (ADS)

We present the design and fabrication of a polymeric capillary fluidic interface fabricated by micro-milling. The design enables the use of glass capillaries with any kind of cross-section in complex microfluidic setups. We demonstrate two different designs of the interface; a double-inlet interface for hydrodynamic focusing and a capillary interface with integrated pneumatic valves. Both capillary interfaces are presented together with examples of practical applications. This communication shows the design optimization and presents details of the fabrication process. The capillary interface opens up for the use of complex microfluidic systems in single-use glass capillaries. They also enable simple fabrication of glass/polymer hybrid devices that can be beneficial in many research fields where a pure polymer chip negatively affects the device's performance, e.g. acoustofluidics.

Evander, Mikael; Tenje, Maria

2014-02-01

210

Automatic Generation of Glomerular Capillary Topological Organization  

Microsoft Academic Search

Glomerular structural changes are conventionally investigated by optical or electron microscopy on two-dimensional (2D) sections. To understand the relationship between functional and structural changes of glomerular capillary networks in more detail, three-dimensional (3D) investigation of the capillary tufts is required. Since confocal microscopy and scanning electron microscopy cannot completely show the 3D topological organization of the capillary tuft, we have

Luca Antiga; Bogdan Ene-Iordache; Giuseppe Remuzzi; Andrea Remuzzi

2001-01-01

211

Simple capillary flow porometer for characterization of capillary columns containing packed and monolithic beds  

Microsoft Academic Search

A simple capillary flow porometer (CFP) was assembled for through-pore structure characterization of monolithic capillary liquid chromatography columns in their original chromatographic forms. Determination of differential pressures and flow rates through dry and wet short capillary segments provided necessary information to determine the mean diameters and size distributions of the through-pores. The mean through-pore diameters of three capillary columns packed

Yan Fang; H. Dennis Tolley; Milton L. Lee

2010-01-01

212

Shape of a Liquid Surface and Capillary Phenomena under Reduced or Zero Gravity  

Microsoft Academic Search

We have studied the capillary properties of a liquid (including molten metals) under reduced or zero gravity: theoretically, by determination of the shape of the liquid surface and the meniscuses by computer integration of the differential equation of capillarity; and experimentally, by modeling weightlessness under terrestrial conditions using small volumes with weak action of the gravitational vector or by creating

Yurii V. Naydich; Ivan I. Gab; Viktor A. Evdokimov; Dina I. Kurkova; Tatyana Stetsyuk

2004-01-01

213

A variational approach to the study of capillary phenomena  

NASA Technical Reports Server (NTRS)

The problem of determining the free surface of a liquid in a capillary tube, and of a liquid drop, sitting first on a horizontal plane and then on more general surfaces is considered. With some modifications, the method applies to the study of pendent drops and of rotating drops as well. The standard capillary problem, i.e. the determination of the free surface of a liquid in a thin tube of general cross section, which resuls from the simultaneous action of surface tension, boundary adhesion and gravity is discussed. It turns out that in this case the existence of the solution surface depends heavily on the validity of a simple geometric condition about the mean curvature of the boundary curve of the cross section of the capillary tube. Some particular examples of physical interest are also be discussed. Liquid drops sitting on or hanging from a fixed horizontal plane are discussed. The symmetry of the solutions (which can actually be proved, as consequence of a general symmetrization argument) now plays the chief role in deriving both the existence and the regularity of energy-minimizing configurations. When symmetry fails (this is the case, for example, when the contact angle between the drop and the plate is not constant, or when the supporting surface is not itself symmetric), then more sophisticated methods must be used. Extensions in this direction are outlined.

Emmer, M.; Gonzalez, E.; Tamanini, I.

1982-01-01

214

PLUMAGE WETTABILITY OF THE AFRICAN DARTER ANHINGA MELANOGASTER COMPARED WITH THE DOUBLE-CRESTED CORMORANT PHALACROCORAX AURITUS  

Microsoft Academic Search

Rijke, A. M., Jesser, W. A. & Mahoney, S. A. 1989. Plumage wettability of the African Darter Anhinga melanogaster compared with the Double-crested Cormorant Phalacrocarax auritus. Ostrich 60:128-132.Darters emerge from water dripping wet but are able to become airborne without delay. Their plumage is, on the whole, three times more wettable than that of cormorants. We investigated the microscopic structure

Arie M. Rijke; William A. Jesser; Sheila A. Mahoney

1989-01-01

215

Influence of textural and wettability variations on predictions of DNAPL persistence and plume development in saturated porous media  

Microsoft Academic Search

Numerical simulations examine the migration, entrapment, and mass recovery behavior of DNAPLs in aquifer systems with coupled textural and wettability variations. Permeability fields of varying degrees of heterogeneity (i.e., differing ?ln(k)2) were generated with sequential Gaussian simulation, using geostatistical parameters derived from core grain size measurements in a sandy glacial outwash aquifer. Organic-wet mass fraction, a representative metric for wettability,

Thomas J. Phelan; Lawrence D. Lemke; Scott A. Bradford; Denis M. O'Carroll; Linda M. Abriola

2004-01-01

216

Capillary rafts and their destabilization  

NASA Astrophysics Data System (ADS)

Small objects trapped at an interface are very common in Nature (insects walking on water, ant rafts, bubbles or pollen at the water-air interface, membranes...) and are found in many multiphase industrial processes. The study of such particle-laden interfaces is therefore of practical as well as fundamental importance. Here we report experiments on the self-assembly of spherical particles into capillary rafts at an oil-water interface and elucidate how such rafts sink. We characterize different types of sinking behavior and show that it is possible to obtain "armored droplets," whereby the sinking oil is encapsulated within a shell of particles.

Protiere, Suzie; Abkarian, Manouk; Aristoff, Jeffrey; Stone, Howard

2010-11-01

217

High pressure pulsed capillary viscometry  

NASA Technical Reports Server (NTRS)

An analytical and test program was conducted in order to establish the feasibility of a multichamber pulsed-capillary viscometer. The initial design incorporated a piston, ram, and seals which produced measured pulses up to 30,000 psi in the closed chamber system. Pressure pulses from one to ten milliseconds were investigated in a system volume of 1 cuin. Four test fluids: a MIL-L-7808, a 5P4E polyphenyl ether, a MIL-L-23699A, and a synthetic hydrocarbon were examined in the test pressure assembly. The pressure-viscosity coefficient and viscosity delay time were determined for the MIL-L-7808 lubricant tested.

Smith, R. L.; Walowitt, J. A.; Pan, C. H. T.

1972-01-01

218

Capillary driven tunable optofluidic DFB dye lasers  

NASA Astrophysics Data System (ADS)

We present the design and operation of low-threshold and widely tunable polymer-based nanofluidic distributed feedback (DFB) dye lasers. The devices rely on light-confinement in a nanostructured polymer film embedded between two substrates. An array of nanofluidic channels forms a Bragg grating DFB laser resonator relying on the third order Bragg reflection. The lasers are fabricated by Combined Electron beam and UV Lithography (CEUL) in a thin film of SU-8 resist and polymer mediated wafer bonding. The devices are operated without the need for external fluidic handling apparatus. Capillary action drives the liquid dye infiltration of the nanofluidic DFB lasers and accounts for dye replenishment. The low Bragg reflection order yields: (i) low out-of-plane scattering losses, (ii) low coupling losses for the light when traversing the dye-filled nanofluidic channels due to the sub-wavelength dimensions of the resonator segments, and (iii) a large free spectral range (FSR). Points (i)+(ii) enable a low threshold for lasing, point (iii) facilitates wavelength tuning over the full gain spectrum of the chosen laser dye without mode-hopping. By combining different grating periods and dye solution refractive indices, we demonstrate a tuning range of 45 nm using a single laser dye and obtain laser threshold fluences down to ~ 7 ?J/mm2. The lasers are straightforward to integrate on lab-on-a-chip microsystems, e.g. for novel sensor concepts, where coherent light in the visible range is desired.

Gersborg-Hansen, Morten; Kristensen, Anders

2007-09-01

219

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

220

Mechanical and wettability properties of chemically modified surface texture with carbon nanotubes  

NASA Astrophysics Data System (ADS)

In this study, surface textures were fabricated and used to improve mechanical durability for superhydrophobic and low-hysteresis surfaces. LIGA-fabrication lithography was combined with a spray-coating method to create hierarchical structures of surface-texture composites with carbon nanotubes (CNTs). The effect that surface coverage of these textures has on surface wettability has been investigated. Poly(methyl methacrylate) was used to strengthen the bond between CNTs and the surface texture. The wettability transition between superhydrophilicity and superhydrophobicity can be switched by UV irradiation. The dynamics of liquid droplets was investigated as well. Also. the mechanical durability of the fabricated surfaces was evaluated by a universal ball-on-plate tribometer. The results indicate that the CNT/textured surface exhibits a strong potential for durable extension of superhydrophobic surfaces.

Mo, Yufei; Yan, Dayun; Huang, Fuchuan

2014-03-01

221

Regulating surface wettability of PEO/PLLA composite electrospun nanofibrous membrane for liquid phase filtration  

NASA Astrophysics Data System (ADS)

The PEO/PLLA composite nanofibrous membranes were prepared by electrospinning technique for liquid phase filtration application. In this experiment, PLLA homopolymer and PLLA-PEG copolymer were added into PEO solution to increase hydrophobicity of nanofibrous membrane surface. PLLA content was fixed at 30% by weight of total solid. Morphology and fiber diameter were characterized from scanning electron microscope (SEM) images. Fiber diameters of PEO/PLLA homopolymer and PEO/PLLA-PEG copolymer are 582+/-78 nm and 657+/-167 nm, respectively. Surface wettability property of PEO/PLLA composite nanofibrous membranes were measured by apparent water contact angle. The apparent water contact angle value of PEO/PLLA is 120+/-2, while PEO/PEG-b-PLLA is 99+/-7. The surface wettability of PEO/PLLA composite nanofibrous membranes can be modified by varying type of polymer.

Poonsit, Lalada; Sunthornvarabhas, Jackapon; Akira, Ito; Lertworasirikul, Amornrat

2014-06-01

222

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

223

Influence of surface topography and chemical structure on wettability of electrodeposited ZnO thin films  

NASA Astrophysics Data System (ADS)

The wettability of electrodeposited zinc oxide (ZnO) thin films has been rationally controlled by individually engineering surface topography and surface chemical structure. We have studied the wettability of hydrophobic ZnO thin films that were rendered ultrahydrophobic by coating with low surface-energy self-assembled monolayer of octadecyltrichlorosilane and also hydrophilized by annealing at elevated temperature in air ambient. The as deposited ZnO film was hydrophobic with contact angle of around 1053 against water, while the annealed films were distinctly hydrophilic. The silanized films were ultrahydrophobic with a contact angle of 1433. The films could be successfully tailored to obtain hydrophilic, hydrophobic as well as ultrahydrophobic behavior. It is likely that similar tunable wetting behavior may be observed in other oxide materials also.

Patra, S.; Sarkar, S.; Bera, S. K.; Paul, G. K.; Ghosh, R.

2010-10-01

224

21 CFR 864.6150 - Capillary blood collection tube.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Capillary blood collection tube. 864.6150 Section...Hematology Devices 864.6150 Capillary blood collection tube. (a) Identification. A capillary blood collection tube is a plain or...

2010-04-01

225

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

226

Wettability control of a polymer surface through 126 nm vacuum ultraviolet light irradiation  

Microsoft Academic Search

The control of the surface wettability of poly (methyl methacrylate) (PMMA) substrates has been successfully demonstrated using an Ar2* excimer lamp radiating 126 nm vacuum ultraviolet (VUV) light. Each of the samples was exposed to 126 nm VUV light in air over the pressure range of 210-4-105 Pa. Although at the process pressures of 10, 103, and 105 Pa, the

Atsushi Hozumi; Naoto Shirahata; Youichiro Nakanishi; Shuuichi Asakura; Akio Fuwa

2004-01-01

227

Deposit buildup on prosthetic eye material (in vitro) and its effect on surface wettability  

PubMed Central

Background The aim of this in-vitro study was to investigate the effect of different polishing standards on prosthetic eye material (poly(methyl methacrylate) [PMMA]) on surface wettability and the rate of protein and lipid buildup. Methods Sample disks (12 mm diameter 1 mm thickness) of PMMA were polished to three different standards of surface finish: low, normal, and optical quality contact lens standard. The sample disks were incubated in a protein-rich artificial tear solution (ATS) for the following periods of time: 1 second, 30 minutes, 1 hour, 4 hours, 24 hours, and 14 days. Surface wettability was measured with a goniometer before and after protein deposits were removed. One-way analysis of variance and paired-samples t-test were used for the statistical analysis. Results Between 13.64 and 62.88 ?g of protein adhered to the sample disks immediately upon immersion in ATS. Sample disks with the highest polish attracted less protein deposits. The sample disks polished to optical quality contact lens standard were more wettable than those less highly polished, and wettability significantly decreased following removal of protein deposits. The addition of lipids to protein-only ATS made no difference to the amount of protein deposited on the sample disks for any of the standards of surface polish tested. Conclusion The findings are consistent with the results of the in-vivo investigation reported previously by the authors. Our view that the minimum standard of polish for prosthetic eyes should be optical quality contact lens standard and that deposits on PMMA prosthetic eyes improve the lubricating properties of the socket fluids has been reinforced by the results of this study. PMID:23430311

Pine, Keith Raymond; Sloan, Brian; Han, KyuYeon Ivy; Swift, Simon; Jacobs, Robert John

2013-01-01

228

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

Microsoft Academic Search

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

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

1993-01-01

229

Highly effective gold nanoparticle-enhanced biosensor array on the wettability controlled substrate by wiping  

Microsoft Academic Search

We demonstrate the use of a highly effective biosensor array to fulfill the requirements of high intensity, reduced nonspecific adsorption (NSA), and low sample usage. The mixed self-assembled monolayers (SAMs), consisting of methyl-terminated and methoxy-(polyethylene glycol (PEG))-terminated silanes, were newly applied as the background layer to reduce the background NSA via wettability control. The surface was modified by a plasma

Jongsu Kim; Bongchul Kang; Renata Ku; Chulho Ham; Minyang Yang

2011-01-01

230

Evaporation of Picolitre Droplets on Surfaces with a Range of Wettabilities and Thermal Conductivities  

E-print Network

Talbot, E.L., Berson, A., Brown, P.S. and Bain, C.D., Submitted to Physical Review E, 'Evaporation of Picolitre Droplets on Surfaces with a Range of Wettabilities and Thermal Conductivities' (accepted) Evaporation of Picolitre Droplets on Surfaces... , Durham, DH1 3LE, United Kingdom (Dated: June 8, 2012) The evaporation of picolitre water and ethanol droplets generated by Drop-on-Demand inkjet printing was investigated on substrates with apparent contact angles between 10? and 135? and thermal...

Talbot, E.L.; Berson, A.; Brown, P.S.; Bain, C.D.

2012-01-01

231

Morphology Influence on Water Wettability of mo Back Contact of Solar Cells  

NASA Astrophysics Data System (ADS)

Investigation of influence of Mo deposition on glass substrates by SIAD on its surface topography and wettability was conducted. We observe several steps in the process of the film growth. Contact angle measurements showed that deposition of the Mo films on glass makes the surface less hydrophilic. With an increase of the irradiation dose, the roughness and contact angle increase rapidly at first and then decreases.

Turavets, A.; Tashlykov, I.

2013-05-01

232

Contact interactions and wettability of cubic boron nitride polycrystal with gold alloys containing transition metal additives  

Microsoft Academic Search

The wettability of cubic boron nitride with gold alloys containing vanadium, tantalum, niobium, and titanium additives as well as contact interactions between cBN and alloy were studied. Experiments were carried out in vacuum of 1E-03 Pa in the temperature range of 11001400 C. For the systems studied, the adhesion work of cBN towards the alloys was calculated. From the results

W. B. Perevertailo; O. B. Loginova

1998-01-01

233

Structural, surface wettability and antibacterial properties of HPMC-ZnO nanocomposite  

NASA Astrophysics Data System (ADS)

The developed hydroxypropyl methylcellulose (HPMC)/Zinc oxide (ZnO) nanocomposite films were examined for structural property and surface wettability using X-ray diffraction and contact angle measurement. Antibacterial activity of these films was evaluated as a function of ZnO concentration. The microstructuralline parameters ( and (g in %)) decreased with increasing concentration of ZnO nanoparticles and there was increase in hydrophilicity. Addition of ZnO nanoparticles in films resulted in antimicrobial activity against tested microorganisms.

Rao, B. Lakshmeesha; Asha, S.; Madhukumar, R.; Latha, S.; Gowda, Mahadeva; Shetty, G. Rajesha; Chandra, K. Sharath; Naik, Prashantha; Sangappa

2014-04-01

234

Experiments on the Motion of Drops on a Horizontal Solid Surface due to a Wettability Gradient  

NASA Technical Reports Server (NTRS)

Results from experiments performed on the motion of drops of tetraethylene glycol in a wettability gradient present on a silicon surface are reported and compared with predictions from a recently developed theoretical model. The gradient in wettability was formed by exposing strips cut from a silicon wafer to decyltrichlorosiland vapors. Video images of the drops captured during the experiments were subsequently analyzed for drop size and velocity as functions of position along the gradient. In separate experiments on the same strips, the static contact angle formed by small drops was measured and used to obtain the local wettability gradient to which a drop is subjected. The velocity of the drops was found to be a strong function of position along the gradient. A quasi-steady theoretical model that balances the local hydrodynamic resistance with the local driving force generally describes the observations; possible reasons for the remaining discrepancies are discussed. It is shown that a model in which the driving force is reduced to accomodate the hysteresis effect inferred from the data is able to remove most of the discrepancy between the observed and predicted velocities.

Moumen, Nadjoua; Subramanian, R, Shankar; MLaughlin, john B.

2006-01-01

235

Influence of surface topography and surface physicochemistry on wettability of zirconia (tetragonal zirconia polycrystal).  

PubMed

Surface modification technologies are available for tetragonal zirconia polycrystal (TZP) to enhance its bioactivity and osseointegration capability. The surface wettability of an implant material is one of the important factors in the process of osseointegration, possibly regulating protein adsorption, and subsequent cell behavior. The aim of this study was to clarify the effect of topographical or physicochemical modification of TZP ceramics on wettability to determine the potential of such treatment in application to implants. Several types of surface topography were produced by alumina blasting and acid etching with hydrofluoric acid; surface physicochemistry was modified with oxygen (O(2)) plasma, ultraviolet (UV) light, or hydrogen peroxide treatment. The obtained specimens were also subjected to storage under various conditions to evaluate their potential to maintain superhydrophilicity. The results showed that surface modification of surface topography or physicochemistry, especially of blast/acid etching as well as O(2) plasma and UV treatment, greatly increased the surface wettability, resulting in superhydrophilicity. X-ray photoelectron spectroscopy revealed that a remarkable decrease in carbon content and the introduction of hydroxyl groups were responsible for the observed superhydrophilicity. Furthermore, superhydrophilicity was maintained, even after immersion in an aqueous solution, an important consideration in the clinical application of this technology. PMID:23165774

Noro, Akio; Kaneko, Morio; Murata, Isao; Yoshinari, Masao

2013-02-01

236

Morphing and vectoring impacting droplets by means of wettability-engineered surfaces  

PubMed Central

Driven by its importance in nature and technology, droplet impact on solid surfaces has been studied for decades. To date, research on control of droplet impact outcome has focused on optimizing pre-impact parameters, e.g., droplet size and velocity. Here we follow a different, post-impact, surface engineering approach yielding controlled vectoring and morphing of droplets during and after impact. Surfaces with patterned domains of extreme wettability (high or low) are fabricated and implemented for controlling the impact process during and even after rebound a previously neglected aspect of impact studies on non-wetting surfaces. For non-rebound cases, droplets can be morphed from spheres to complex shapes without unwanted loss of liquid. The procedure relies on competition between surface tension and fluid inertial forces, and harnesses the naturally occurring contact-line pinning mechanisms at sharp wettability changes to create viable dry regions in the spread liquid volume. Utilizing the same forces central to morphing, we demonstrate the ability to rebound orthogonally-impacting droplets with an additional non-orthogonal velocity component. We theoretically analyze this capability and derive a We?.25 dependence of the lateral restitution coefficient. This study offers wettability-engineered surfaces as a new approach to manipulate impacting droplet microvolumes, with ramifications for surface microfluidics and fluid-assisted templating applications. PMID:25392084

Schutzius, Thomas M.; Graeber, Gustav; Elsharkawy, Mohamed; Oreluk, James; Megaridis, Constantine M.

2014-01-01

237

WETTABILITY ALTERATION OF CARBONATE ROCK MEDIATED BY BIOSURFACTANT PRODUCED FROM HIGH-STARCH AGRICULTURAL EFFLUENTS  

SciTech Connect

Surfactants can be used to alter wettability of reservoir rock, increasing spontaneous imbibition and thus improving oil yields. Commercial synthetic surfactants are often prohibitively expensive and so a crude preparation of the anionic biosurfactant, surfactin, from Bacillus subtilis grown on high-starch industrial and agricultural effluents has been proposed as an economical alternative. To assess the effectiveness of the surfactin, it is compared to commercially available surfactants. In selecting a suitable benchmark surfactant, two metrics are examined: the ability of the surfactants to alter wettability at low concentrations, and the degree to which they are absorbed onto reservoir matrix. We review the literature to survey the adsorption models that have been developed to describe surfactant adsorption in porous media. These models are evaluated using the experimental data from this study. Crushed carbonate rock samples are cleaned and aged in crude oil. The wettability change mediated by dilute solutions of commercial anionic surfactants and surfactin is assessed using a two-phase separation; and surfactant loss due to retention and adsorption the rock is determined.

Mehdi Salehi; Stephen Johnson; Gregory Bala; Jenn-Tai Liang

2006-09-01

238

Morphing and vectoring impacting droplets by means of wettability-engineered surfaces.  

PubMed

Driven by its importance in nature and technology, droplet impact on solid surfaces has been studied for decades. To date, research on control of droplet impact outcome has focused on optimizing pre-impact parameters, e.g., droplet size and velocity. Here we follow a different, post-impact, surface engineering approach yielding controlled vectoring and morphing of droplets during and after impact. Surfaces with patterned domains of extreme wettability (high or low) are fabricated and implemented for controlling the impact process during and even after rebound -a previously neglected aspect of impact studies on non-wetting surfaces. For non-rebound cases, droplets can be morphed from spheres to complex shapes -without unwanted loss of liquid. The procedure relies on competition between surface tension and fluid inertial forces, and harnesses the naturally occurring contact-line pinning mechanisms at sharp wettability changes to create viable dry regions in the spread liquid volume. Utilizing the same forces central to morphing, we demonstrate the ability to rebound orthogonally-impacting droplets with an additional non-orthogonal velocity component. We theoretically analyze this capability and derive a We(-.25) dependence of the lateral restitution coefficient. This study offers wettability-engineered surfaces as a new approach to manipulate impacting droplet microvolumes, with ramifications for surface microfluidics and fluid-assisted templating applications. PMID:25392084

Schutzius, Thomas M; Graeber, Gustav; Elsharkawy, Mohamed; Oreluk, James; Megaridis, Constantine M

2014-01-01

239

Versatile wettability gradients prepared by chemical modification of polymer brushes on polymer foils.  

PubMed

A method to create a wettability gradient by variation of the chemical functionality in a polymer brush is presented. A poly(N-methyl-vinylpyridinium) (QP4VP) brush was created on a poly(ethylene-alt-tetrafluoroethylene) (ETFE) foil by the grafting of 4-vinylpyridine and subsequent quaternization. The instability of QP4VP, a strong polyelectrolyte, in alkaline media was exploited to transform it to the neutral poly(vinyl(N-methyl-2-pyridone)) (PVMP), as confirmed with ATR-IR spectroscopy. The slow transformation resulted in a substantial, time-dependent decrease in wettability. A nearly linear gradient in water contact angle (CA) was created by immersion of a QP4VP brush modified sample into a sodium hydroxide solution, resulting in CAs ranging from 10 to 60. The concurrent decrease in the number of charged functional groups along the gradient was characterized by loading an anionic dye into the polymer brush and measuring the UV transmittance of the sample. The versatility of the wettability gradient was demonstrated by exchanging the counterions of the N-methyl-vinylpyridinium groups, whereby a reversal of gradient direction was reproducibly achieved. PMID:21568351

Neuhaus, Sonja; Padeste, Celestino; Spencer, Nicholas D

2011-06-01

240

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 characteristicwettability. 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. PMID:16849215

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

2005-01-01

241

Interfacial dynamics of two immiscible fluids in spatially periodic porous media: the role of substrate wettability.  

PubMed

We delineate the contact line dynamics of two immiscible fluids in a medium having spatially periodic porous structures. The flow is driven by an external applied pressure gradient. We bring out the combined consequences of the solid fraction distribution and the substrate wettability on the resulting dynamics of the contact line, by employing phase-field formalism. We capture the sequence of spatiotemporal events leading to formation of liquid bridges by trapping a small amount of displaced phase fluid between two consecutive porous blocks, as dictated by the combinations of substrate wettability and solid fraction. We also demonstrate the existence of a regime of complete interfacial recovery, depending on the parametric space of the governing parameters under concern. Our results essentially demonstrate the intricate mechanisms by virtue of which the wettabilities of the substrates alter the dynamical evolutions of interfaces and the subsequent shapes and sizes of the adsorbed dispersed phases, bearing far-ranging consequences in several practical applications ranging from oil recovery to groundwater flow. PMID:25122365

Mondal, Pranab Kumar; DasGupta, Debabrata; Chakraborty, Suman

2014-07-01

242

Evaluation of capillary reinforced composites  

NASA Technical Reports Server (NTRS)

Anti-icing of the inlet of jet engines is generally performed with high pressure heated air that is directed forward from the compressor through a series of pipes to various manifolds located near the structures to be anti-iced. From these manifolds, the air is directed to all flowpath surfaces that may be susceptible to ice formation. There the anti-icing function may be performed by either heat conduction or film heating. Unfortunately, the prospect of utilizing lighweight, high strength composites for inlet structures of jet engines has been frustrated by the low transverse thermal conductivity of such materials. It was the objective of this program to develop an advanced materials and design concept for anti-icing composite structures. The concept that was evaluated used capillary glass tubes embedded on the surface of a composite structure with heated air ducted through the tubes. An analytical computer program was developed to predict the anti-icing performance of such tubes and a test program was conducted to demonstrate actual performance of this system. Test data and analytical code results were in excellent agreement. Both indicate feasibility of using capillary tubes for surface heating as a means for composite engine structures to combat ice accumulation.

Cahill, J. E.; Halase, J. F.; South, W. K.; Stoffer, L. J.

1985-01-01

243

Cryogenic capillary screen heat entrapment  

NASA Astrophysics Data System (ADS)

Cryogenic liquid acquisition devices (LADs) for space-based propulsion interface directly with the feed system, which can be a significant heat leak source. Further, the accumulation of thermal energy within LAD channels can lead to the loss of subcooled propellant conditions and result in feed system cavitation during propellant outflow. Therefore, the fundamental question addressed by this program was: "To what degree is natural convection in a cryogenic liquid constrained by the capillary screen meshes envisioned for LADs?" Testing was first conducted with water as the test fluid, followed by liquid nitrogen (LN 2) tests. In either case, the basic experimental approach was to heat the bottom of a cylindrical column of test fluid to establish stratification patterns measured by temperature sensors located above and below a horizontal screen barrier position. Experimentation was performed without barriers, with screens, and with a solid barrier. The two screen meshes tested were those typically used by LAD designers, 200 1400 and 325 2300, both with Twill Dutch Weave. Upon consideration of both the water and LN 2 data, it was concluded that heat transfer across the screen meshes was dependent upon barrier thermal conductivity and that the capillary screen meshes were impervious to natural convection currents.

Bolshinskiy, L. G.; Hastings, L. J.; Statham, G.

2008-05-01

244

Capillary refractometer integrated in a microfluidic configuration.  

PubMed

We propose a microfluidic method to measure the refractive index of liquids. This method is based on the dynamic focusing by a capillary when liquids with different refractive indexes are inserted into it. Fabrication of such a refractometer has been done by encapsulating two fibers and a capillary. A calibration method is proposed. PMID:18288234

Calixto, Sergio; Rosete-Aguilar, Martha; Monzon-Hernandez, David; Minkovich, Vladimir P

2008-02-20

245

Internal capillary insulation for cryogenic tanks  

NASA Technical Reports Server (NTRS)

Capillary-type insulation was devised for installation on inside of liquid methane fuel tanks for future aircraft. Insulation consists of honeycomb core of fiberglass cloth impregnated with polyimide resin which is bonded onto metal tank wall using polyimide adhesive. Capillary holes in each honeycomb cell admit methane which provides static pressure in cell.

Mcgrew, J. L.

1972-01-01

246

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. PMID:20603830

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

2011-01-01

247

Copolymers For Capillary Gel Electrophoresis  

DOEpatents

This invention relates to an electrophoresis separation medium having a gel matrix of at least one random, linear copolymer comprising a primary comonomer and at least one secondary comonomer, wherein the comonomers are randomly distributed along the copolymer chain. The primary comonomer is an acrylamide or an acrylamide derivative that provides the primary physical, chemical, and sieving properties of the gel matrix. The at least one secondary comonomer imparts an inherent physical, chemical, or sieving property to the copolymer chain. The primary and secondary comonomers are present in a ratio sufficient to induce desired properties that optimize electrophoresis performance. The invention also relates to a method of separating a mixture of biological molecules using this gel matrix, a method of preparing the novel electrophoresis separation medium, and a capillary tube filled with the electrophoresis separation medium.

Liu, Changsheng (State College, PA); Li, Qingbo (State College, PA)

2005-08-09

248

Nonlinear waves in capillary electrophoresis  

E-print Network

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, an...

Ghosal, Sandip; 10.1007/s11538-010-9527-2

2012-01-01

249

Hyperosmolarity enhances the lung capillary barrier  

PubMed Central

Although capillary barrier deterioration underlies major inflammatory lung pathology, barrier-enhancing strategies are not available. To consider hyperosmolar therapy as a possible strategy, we gave 15-minute infusions of hyperosmolar sucrose in lung venular capillaries imaged in real time. Surprisingly, this treatment enhanced the capillary barrier, as indicated by quantification of the capillary hydraulic conductivity. The barrier enhancement was sufficient to block the injurious effects of thrombin, TNF-?, and H2O2 in single capillaries, and of intratracheal acid instillation in the whole lung. Capillary immunofluorescence indicated that the hyperosmolar infusion markedly augmented actin filament formation and E-cadherin expression at the endothelial cell periphery. The actin-depolymerizing agent latrunculin B abrogated the hyperosmolar barrier enhancement as well as the actin filament formation, suggesting a role for actin in the barrier response. Furthermore, hyperosmolar infusion blocked TNF-?induced P-selectin expression in an actin-dependent manner. Our results provide the first evidence to our knowledge that in lung capillaries, hyperosmolarity remodels the endothelial barrier and the actin cytoskeleton to enhance barrier properties and block proinflammatory secretory processes. Hyperosmolar therapy may be beneficial in lung inflammatory disease. PMID:14617755

Safdar, Zeenat; Wang, Ping; Ichimura, Hideo; Issekutz, Andrew C.; Quadri, Sadiqa; Bhattacharya, Jahar

2003-01-01

250

Excitation of Capillary Waves in Strongly Absorbing Liquids by a Modulated Laser Beam  

NASA Astrophysics Data System (ADS)

Several mechanisms for the excitation of capillary waves and for the development of the average deformation of a liquid surface under the action of a modulated laser beam are considered. The amplitude of the capillary wave in a strongly absorbing solution of the dye LDS 751 in ethylene glycol is experimentally studied as a function of laser intensity. Consecutive changes in the predominant mechanism of the excitation with increasing laser intensity are observed and described. At low laser intensities the mechanism connected with the creation of a surface tension gradient prevails. This mechanism becomes nonlinear with increasing influence of the convective motion. In addition, pressure pulsations of the convective flow start to contribute significantly to the generation process. The resonances of capillary waves in a cylindrical container are also investigated and used for determining the surface tension and viscosity of the liquid.

Kolomenskii, Alexandre A.; Schuessler, Hans A.

1999-10-01

251

Arrested segregative phase separation in capillary tubes.  

PubMed

Phase separation in a capillary tube with one of the phases fully wetting the capillary wall is arrested when the typical size of the phase domains reaches the value of the diameter of the tube. The arrested state consists of an alternating sequence of concave-capped and convex-capped cylindrical domains, called "plugs," "bridges," or "lenses," of wetting and nonwetting phase, respectively. A description of this arrested plug state for an aqueous mixture of two polymer solutions is the subject of this work. A phase separating system consisting of two incompatible polymers dissolved in water was studied. The phase volume ratio was close to unity. The initial state from which plugs evolve is characterized by droplets of wetting phase in a continuous nonwetting phase. Experiments show the formation of plugs by a pathway that differs from the theoretically well-described instabilities in the thickness of a fluid thread inside a confined fluid cylinder. Plugs appear to form after the wetting layer (the confined fluid cylinder) has become unstable after merging of droplet with the wetting layer. The relative density of the phases could be set by the addition of salt, enabling density matching. As a consequence, the capillary length can in principle be made infinitely large and the Bond number (which represents the force of gravity relative to the capillary force) zero, without considerably changing the interfacial tension. Using the possibility of density matching, the relations among capillary length and capillary diameter on the one hand, and the presence of plugs and their average size on the other were studied. It was found that stable plugs are present when the capillary radius does not exceed a certain value, which is probably smaller than the capillary length. However, the average plug size is independent of capillary length. At constant capillary length, average plug size was found to scale with the capillary diameter to a power 1.3, significantly higher than the expected value of 1. Plug sizes had a polydispersity between 1.1 and 1.2 for all capillary radii for which this number could be reliably determined, suggesting a universal plug size distribution. Within plug sequences, size correlations were found between plugs with one to three plugs in between. This suggests the presence of an additional length scale. PMID:17025640

Tromp, R Hans; Lindhoud, Saskia

2006-09-01

252

Plasma of capillary discharge of low pressure  

NASA Astrophysics Data System (ADS)

Ionization equilibrium is considered for a capillary plasma of low pressure within a scheme where a tail of the energy distribution function of electrons at energies above the atom excitation energy includes a small portion of electrons. The kinetics of a gas discharge plasma in strong fields is developed and allows one to determine the drift velocity of electrons and other parameters of a capillary plasma. The results are applied to a capillary plasma of helium and argon. The analysis leads to the optimal shape of the gas discharge chamber for the formation of a plasma torch with fast electrons.

Smirnov, B. M.; Tereshonok, D. V.

2014-02-01

253

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

254

A computational model of hemodynamic parameters in cortical capillary networks  

Microsoft Academic Search

The analysis of hemodynamic parameters and functional reactivity of cerebral capillaries is still controversial. To assess the hemodynamic parameters in the cortical capillary network, a generic model was created using 2D voronoi tessellation in which each edge represents a capillary segment. This method is capable of creating an appropriate generic model of cerebral capillary network relating to each part of

Navid Safaeian; Mathieu Sellier; Tim David

2011-01-01

255

Local-scale distribution of organic matter composition and wettability at surfaces of preferential flow paths  

NASA Astrophysics Data System (ADS)

Surfaces of preferential flow paths in structured soils consist of clay-organic coatings (i.e., cutanes) on soil aggregates or linings on biopores (i.e., worm burrows and decayed root channels). The outermost layer of such surfaces is mostly covered by organic matter (OM). The composition of this OM finally controls wettability and sorption properties that are relevant for transport along the flow path. However, the local distribution of OM-properties along such surfaces is largely unknown because analyzes without disturbing the coating layer surfaces have not been possible to date. The objective of this study is to compare the local 2D distribution of soil OM composition at intact aggregate and biopore surfaces with that of the wettability. The OM composition is determined using Fourier transformed infrared spectroscopy in diffuse reflectance mode (DRIFT) in terms of the ratios of CH/CO functional molecular groups. Intact surfaces of aggregated soil samples were scanned using a DRIFT mapping procedure in a 1 mm grid. Wettability was observed by means of contact angle measurements using a Goniometer with a high-speed camera. The aggregate sample surfaces were distinguished into regions of earthworm burrows, root channels, clay-organic coatings and uncoated regions. In contrast to the uncoated surface areas, organic coatings on worm burrows and root channels show relatively higher CH/CO-ratios that correspond with longer water drop infiltration. Both, the OM composition of coatings along preferential flow path surfaces and the water repellence are spatially variable at this local scale. The results indicate yet unknown implications for preferential flow and transport especially for reactive solutes.

Leue, Martin; Ellerbrock, Ruth H.; Gerke, Horst H.

2010-05-01

256

An investigation into a micro-sized droplet impinging on a surface with sharp wettability contrast  

NASA Astrophysics Data System (ADS)

An experimental investigation was conducted into a micro-sized droplet jetted onto a surface with sharp wettability contrast. The dynamics of micro-sized droplet impingement on a sharp wettability contrast surface, which is critical in inkjet printing technology, has not been investigated in the literature. Hydrophilic lines with line widths ranging from 27 to 53 µm, and contact angle ranging from 17° to 77°, were patterned on a hydrophobic surface with a contact angle of 107°. Water droplets with a diameter of 81 µm were impinged at various offset distances from the centre of the hydrophilic line. The evolution of the droplet upon impingement can be divided into three distinct phases, namely the kinematic phase, the translating phase where the droplet moves towards the centre of the hydrophilic line, and the conforming phase where the droplet spreads along the line. The key parameters affecting the conformability of the droplet to the hydrophilic line pattern are the ratio of the line width to the initial droplet diameter and the contact angle of the hydrophilic line. The droplet will only conform completely to the hydrophilic pattern if the line width is not overly small relative to the droplet and the contact angle of the hydrophilic line is sufficiently low. The impact offset distance does not affect the final shape and final location of the droplet, as long as part of the droplet touches the hydrophilic line upon impingement. This process has a significant impact on inkjet printing technology as high accuracy of inkjet droplet deposition and shape control can be achieved through wettability patterning.

Lim, C. Y.; Lam, Y. C.

2014-10-01

257

?-cyclodextrin and its hyperbranched polymers-induced micro/nanopatterns and tunable wettability on polymer surfaces  

NASA Astrophysics Data System (ADS)

This paper reports an efficient strategy to fabricate micro/nanopatterns on the surfaces of polymers for obtaining tunable wettability. Tepee-like bundles as micro/nanopatterns, composed of irregular polygon ``podium'' and ``valley'' structures, are formed by adding ?-cyclodextrin (?-CD) or its hyperbranched polymers [HBP(?-CD)s] into a polystyrene (PS) matrix in the process of anodized aluminum oxide (AAO) template wetting. The degree and region of micro/nanopatterns are evidently enlarged with the increase of ?-CD content or the molecular weight (Mw) of HBP(?-CD). The formation of micro/nanopatterns is mainly dependant on the self-organization of long and flexible aligned nanofiber/nanotube arrays with high aspect ratios, which are generated by the enhanced nanoflow behaviors of ?-CD or HBP(?-CD)-containing PS melts in AAO templates. The final topographies of micro/nanopatterns are determined by the dilation stress and the interactions of nanofibers/nanotubes during the template's removal and solvent evaporation process. The static and dynamic water contact angle measurements show that the wettability of micro/nanopatterned surfaces is systematically tuned from being merely hydrophobic to being highly hydrophobic, and to being finally superhydrophobic by simply adjusting the content of ?-CD or the Mw of HBP(?-CD) due to the decrease of the contact area fraction of the water droplet and solid polymer. The reported novel method, using nanoparticles or hyperbranched polymers as processing aids to induce micro/nanopatterns and tunable wettability on polymer surfaces, may be extended to various polymeric matrices to realize nanopatterns, and is useful for tailoring artificial superhydrophobic surfaces as well.

Tian, Wei; Xu, Yan; Huang, Longbiao; Yung, Kai-Leung; Xie, Yunchuan; Chen, Wei

2011-12-01

258

Wettability and its influence on graphene nansoheets as electrode material for capacitive deionization  

NASA Astrophysics Data System (ADS)

Wetting behavior on graphene nanosheets and their application in capacitive deionization were discussed in this research. By altering the hydrophilicity of graphene nanosheets (GNS) through controlled introduction of sulphonic groups, the water contact angle of GNS is much reduced, indicating a better wettability. Meanwhile, the sulphonated GNS showed better dispersion and higher specific surface area, probably due to the negatively charged -SO3- acting as a repellent on the surface to prevent serious aggregation. As a result, a salt removal efficiency of 83.4% and specific electrosorptive capacity of 8.6 mg/g, indicating an increase of 109% comparing with the unmodified GNS.

Jia, Baoping; Zou, Linda

2012-10-01

259

Self-erasing and rewritable wettability patterns on ZnO thin films  

SciTech Connect

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; Ras, Robin H. A. [Department of Applied Physics, Aalto University, P.O. Box 15100, FI-00076 Aalto, Espoo (Finland); Sahramo, Elina; Malm, Jari; Karppinen, Maarit [Department of Chemistry, Aalto University, P.O. Box 16100, FI-00076 Aalto, Espoo (Finland)

2010-07-26

260

An investigation of the effects of wettability on oil recovery after water flooding  

E-print Network

, and in no previous work bas the wettability been varied while holding the 1ntex facial tension constant. It is highly probable in most of the 12 previous work, excepting that of Calhoun and Bethel, that of' ~ and Hsiao 3, and that of Querrero+ and of Barge, that... it ware present it would offer no res)stance to movement because the summation of statio forces all around the droplet would be sero. However, Uartell 'WATER SOLI D OIL TOW TOS TWS FLOW WATER IL eI TOW Tws SOLID TOS Fl GURE 7 and NsrrD. 1...

Boykin, Robert Stith

2012-06-07

261

Study on the soldering in partial melting state (1) analysis of surface tension and wettability  

Microsoft Academic Search

This paper introduces the partial melting process for solder application and characterization of its feasibility using Pb-Sn,\\u000a Ag-Sn, Sn-Cu, Sn-In and Sn-Bi alloys. In order to show that the liquid phase in the semi-liquid state maintains the similar\\u000a wettability as the single-phase liquid, the wetting balance tests are conducted with varying temperatures and compositions.\\u000a The results are then compared with

Jae Yong Park; Jun Seok Ha; Choon Sik Kang; Kyu Sik Shin; Moon Il Kim; Jae Pil Jung

2000-01-01

262

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

263

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

264

Multistaged stokes injected Raman capillary waveguide amplifier  

DOEpatents

A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

Kurnit, Norman A. (Santa Fe, NM)

1980-01-01

265

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

266

Two phase flow in capillary tubes  

E-print Network

The flow of two phases, gas and liquid, has been studied in horizontal tubes of capillary diameter. The flow has been primarily studied in the regime where the gas flows as long bubbles separated from the wall of the tube ...

Suo, Mikio

1963-01-01

267

CAPILLARY ELECTROPHORETIC BEHAVIOR OF SEVEN SULFONYLUREAS  

EPA Science Inventory

The electrophoretic behavior of bensulfuron Me, sulfometuron Me, nicosulfuron (Accent), chlorimuron Et, thifensulfuron Me (Harmony), metsulfuron Me, and chlorsulfuron was studied under capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) conditio...

268

Geometry and wetting of capillary folding  

E-print Network

Capillary forces are involved in a variety of natural phenomena, ranging from droplet breakup to the physics of clouds. The forces from surface tension can also be exploited in industrial applications provided the length ...

Lauga, Eric

269

Modeling blood flow in pulmonary capillary networks  

Microsoft Academic Search

\\u000a Understanding the mechanisms of perfusion in pulmonary capillary networks is essential for understanding gas exchange between\\u000a air and blood. A two-phase-fluid model was developed to investigate mechanisms of blood perfusion and distribution of erythrocytes\\u000a in the capillary of the lung. Rheological investigation of the model fluid was performed showing non-Newtonian behavior of\\u000a the model. The flow around red blood cell

S. Weber; M. Bonfantini; K. Schirrmann; U. Kertzscher; K. Affeld

270

Capillary Instability of Free Liquid Jets  

Microsoft Academic Search

\\u000a This chapter deals with capillary instability of straight free liquid jets moving in air. It begins with linear stability\\u000a theory for small perturbations of Newtonian liquid jets and discusses the unstable modes, characteristic growth rates, temporal\\u000a and spatial instabilities and their underlying physical mechanisms. The linear theory also provides an estimate of the main\\u000a droplet size emerging from capillary breakup.

N. Ashgriz; A. L. Yarin

271

Aptamers in Affinity Separations:Capillary Electrophoresis  

Microsoft Academic Search

Assays employing aptamers in capillary electrophoresis (CE), including competitive and noncompetitive assays, fluorescence polarization (FP) assays, nonequilibrium capillary electrophoresis of equilibrium mixtures, and affinity-polymerase chain reaction-CE assays, are summarized. These assays can be used to estimate dissociation rate and equilibrium binding constants, determine binding stoichiometries, study molecular interactions, and quantitatively determine specific analytes (e.g., proteins) in complex media. They can

Jeffrey W. Guthrie; Yuanhua Shao; X. Chris Le

2009-01-01

272

Capillary filling in microchannels patterned by posts  

E-print Network

We investigate the capillary filling of three dimensional micro-channels with surfaces patterned by posts of square cross section. We show that pinning on the edges of the posts suppresses, and can halt, capillary filling. We stress the importance of the channel walls in controlling whether filling can occur. In particular for channels higher than the distance between adjacent posts, filling occurs for contact angles less than a threshold angle \\sim 55 deg., independent of the height of the channel.

B. M. Mognetti; J. M. Yeomans

2009-10-27

273

Pediatric Nasal Lobular Capillary Hemangioma  

PubMed Central

Background. LCH is a benign vascular growth of the skin and mucous membranes commonly affecting the head and neck. Since it was first described in the nineteenth century, this entity has been variously known as human botryomycosis and pyogenic granuloma. The shifting nomenclature reflects an evolving understanding of the underlying pathogenesis. We review the histopathology of and current epidemiological data pertaining to LCH which suggests that the development of these lesions may involve a hyperactive inflammatory response influenced by endocrine factors. We report two new cases of pediatric lobular capillary hemangioma (LCH) of the nasal cavity and review current theories regarding the etiology, diagnosis, and treatment of nasal LCH. Methods. Retrospective case series. Case Series. Two adolescent females presented with symptoms of recurrent epistaxis, nasal obstruction, and epiphora. Both patients underwent computed tomography imaging and biopsy of their intranasal mass. The tumors were excised using image-guided transnasal endoscopic technique. Seven other cases of nasal LCH have been reported to date in the pediatric population. Conclusion. Nasal LCH is a rare cause of an intranasal mass and is associated with unilateral epistaxis, nasal obstruction, and epiphora. We advocate for image-guided endoscopic excision of LCH in the adolescent population. PMID:22919398

Virbalas, Jordan M.; Bent, John P.; Parikh, Sanjay R.

2012-01-01

274

Capillary fracture of soft gels  

E-print Network

A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact-line in a starburst pattern. In this paper, we characterize i) the initiation process in which the number of arms in the starburst is controlled by the ratio of surface tension contrast to the gel's elastic modulus and ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law $L\\propto t^{3/4}$. We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid/solid wetting forces. The elastic solution shows that both the location and magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an impo...

Bostwick, Joshua B

2013-01-01

275

Capillary fracture of soft gels  

E-print Network

A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact-line in a starburst pattern. In this paper, we characterize i) the initiation process in which the number of arms in the starburst is controlled by the ratio of surface tension contrast to the gel's elastic modulus and ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law $L\\propto t^{3/4}$. We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid/solid wetting forces. The elastic solution shows that both the location and magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material, and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids finding that the latter better explains the observed exponent.

Joshua B. Bostwick; Karen E. Daniels

2013-10-16

276

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. PMID:20238181

Ghosal, Sandip; Chen, Zhen

2011-01-01

277

Wettable and Unsinkable: The Hydrodynamics of Saccate Pollen Grains in Relation to the Pollination Mechanism in the Two New Zealand Species of Prumnopitys Phil. (Podocarpaceae)  

Microsoft Academic Search

The pollination mechanism of most genera of the Podocarpaceae involves inverted ovules, a pollination drop and bisaccate pollen grains. Saccate grains have sometimes been referred to as 'non-wettable' due to their buoy- ant properties, while non-saccate pollen grains have been described as 'wettable'. The hydrodynamic properties of saccate pollen grains of seven podocarp species in five genera, Dacrydium Sol. ex

JOSHUA S ALTER; B RIAN G. M URRAY; J OHN; E. B RAGGINS

278

The Wettability of LaRC Colorless Polyimide Resins on Casting Surfaces  

NASA Technical Reports Server (NTRS)

Two colorless polyimides developed at NASA Langley Research Center, LaRC -CP1 and LaRC -CP2, are noted for being optically transparent, resistant to radiation, and soluble in the imide form. These materials may be used to make transparent, thin polymer films for building large space reflector/collector inflatable antennas, solar arrays, radiometers, etc. Structures such as these require large area, seamless films produced via spin casting or spray coating the soluble imide on a variety of substrates. The ability of the soluble imide to wet and spread over the mandrel or casting substrate is needed information for processing these structures with minimum waste and reprocessing, thereby, reducing the production costs. The wettability of a liquid is reported as the contact angle of the solid/liquid system. This fairly simple measurement is complicated by the porosity and the amount of contamination of the solid substrate. This work investigates the effect of inherent viscosity, concentration of polyimide solids, and solvent type on the wettability of various curing surfaces.

Miner, Gilda A.; Stoakley, Diane M.; St.Clair, Anne K.; Gierow, Paul A.; Bates, Kevin

1997-01-01

279

Tolerance to Systemic Isotretinoin Therapy in Two Patients Using Highly Wettable Contact Lenses  

PubMed Central

Purpose. Numerous ocular side effects have been reported with the use of systemic isotretinoin therapy. Herein, we presented two contact lens user patients who did not have contact lens intolerance during systemic isotretinoin therapy. Methods. 25-year-old male and 20-year-old female patients with severe acne vulgaris who were using highly wettable silicone hydrogel contact lenses which increase tear film stability were examined. Tear film function tests including Schirmer tests and tear break up time (TBUT) test and ocular surface staining with fluorescein were done. Subjective ocular complaints were scored with ocular surface disease index (OSDI) questionnaire. Patients were followed up monthly and examinations were repeated at each visit. Results. Both patients completed the therapy after a cumulative dose of 140?mg/kg isotretinoin in 6 months. The OSDI score and tear film function tests before and after treatment were all within normal limits. Discussion. Highly wettable contact lenses that provide increase in the tear film stability may be used during systemic retinoid therapy under close followups. Although isotretinoin affects ocular glands, the differences between tolerances to this retinoid therapy need to be investigated in larger patient groups using contact lenses. PMID:24707422

Arman, Aysegul; Demirseren, D. Deniz

2014-01-01

280

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

2013-10-21

281

Investigating the effect of different asphaltene structures on surface topography and wettability alteration  

NASA Astrophysics Data System (ADS)

This paper aims at investigation of the effect of asphaltene structure on wettability and topography alteration of a glass surface as a result of asphaltene precipitation. In order to provide a better insight into the topography alteration, a bi-fractal approach was employed. Such an approach is capable of discriminating topography alteration in two different surface types, namely, macro-asperities and micro-asperities. The observed variation of the fractal dimension in the two surface types could be considered as the consequence of different asphaltene sources. Therefore, the structure of different asphaltene sources was carefully examined. The effect of asphaltene structure is more pronounced for asphaltene precipitation at higher pressure. It was revealed that asphaltene particles of high complexity and with larger poly-aromatic rings tend to be detached easier at higher pressure than those with smaller poly-aromatic rings. Another evidence to emphasize the significance of asphaltene structure was given through wettability alteration. It was found that asphaltene particles with larger poly-aromatic rings turn the surface less oil wet at higher pressure. It seems that the difference in wetting condition and surface topography alteration of different asphaltene sources roots in their different structures.

Amin, J. Sayyad; E. Nikooee; Ghatee, M. H.; Ayatollahi, Sh.; Alamdari, A.; Sedghamiz, T.

282

Surface Energy Engineering for Tunable Wettability through Controlled Synthesis of MoS2  

NASA Astrophysics Data System (ADS)

MoS2 is one of the important members of transition metal dichalogenides which is emerging as a potential 2D atomically thin layered material for low power electronic and opto-electronic applications. However, for MoS2 a critical fundamental question of significant importance is how the surface energy and hence the wettability is altered in nanoscale -- in particular, the role of crystal quality in low dimensions. Present work reports the synthesis of large area MoS2 films on insulating substrates with different surface morphology via vapor phase deposition by varying the growth temperatures. The crystallinity of the samples is examined by transmission electron microscopy and Raman spectroscopy. From contact angle measurements, it is possible to correlate the wettability with crystallinity at nanoscale. The specific surface energy for few layers thick MoS2 is estimated to be around 46.5 mJ/m2. Our results shed light on the MoS2-water interaction which is significant for developing important devices based on MoS2 coated surfaces for micro-fluidic applications.

Gaur, Anand P. S.; Sahoo, Satyaprakash; Ahmadi, Majid; Dash, Saroj P.; Guinel, Maxime J.-F.; Katiyar, Ram S.

2014-08-01

283

Wettability and impact dynamics of water droplets on rice ( Oryza sativa L.) leaves  

NASA Astrophysics Data System (ADS)

We investigated the wettability and impact dynamics of water droplets on rice leaves at various leaf inclination angles and orientations. Contact angle, contact angle hysteresis (CAH), and roll-off angle ( ? roll) of water droplets were measured quantitatively. Results showed that droplet motion exhibited less resistance along the longitudinal direction. Impact dynamic parameters, such as impact behaviors, maximum spreading factor, contact distance, and contact time were also investigated. Three different impact behaviors were categorized based on the normal component of Weber number irrespective of the inclination angle of the rice leaf. The asymmetric impact behavior induced by the tangential Weber number was also identified. Variation in the maximum spreading factor according to the normal Weber number was measured and compared with theoretical value obtained according to scaling law to show the wettability of the rice leaves. The contact distance of the impacting droplets depended on the inclination angle of the leaves. Along the longitudinal direction of rice leaves, contact distance was farther than that along the transverse direction. This result is consistent with the smaller values of CAH and ? roll along the longitudinal direction.

Kwon, Dae Hee; Huh, Hyung Kyu; Lee, Sang Joon

2014-03-01

284

Management of microscale two-phase transport through surface structure and wettability control  

NASA Astrophysics Data System (ADS)

The surface structure modification and wettability control are very crucial issues for the technological advancement in microfluidic systems. This thesis utilizes two unique approaches to improve the water and air management of micro Direct Methanol Fuel Cell (DMFC). The silicon wafer is formed of the alternate strips of hydrophobic and hydrophilic channels with different array of opening sizes. Water will be guided along the hydrophilic wetting channels with large opening holes; it is then collected while the air goes into the cathode from the hydrophobic dry areas with smaller holes. The second approach utilizes the pumpless water management system. The present approach uses a Teflon membrane, with hydrophobic features instead of carbon paper to build a hydraulic pressure that forced some or most of the liquid-water back to the anode. As a result, there is no need for a pump. The overall test is successful and the present Teflon sheet is able to prevent the liquid from penetrating through the sheet while allowing the feeding of gas molecules across the sheet. Therefore, it clearly indicated that the concept of pumpless water management system is feasible although some improvements could be made in the future. Therefore, this study demonstrates successfully that the proper modification of surface structure and wettability control leads to solving many difficult concerns not specific in DMFC but also in other applications as in the case of the bio-chip systems.

Alyousef, Yousef M.

285

Morphology and wettability of ZnO nanostructures prepared by hydrothermal method on various buffer layers  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanostructures were prepared by hydrothermal method on glass substrates with various buffer layers: Ag, Al, aluminum-doped zinc oxide (AZO) and tin-doped indium oxide (ITO). The structure, morphology and wettability of the ZnO nanostructured surfaces were investigated by using X-ray diffraction, scanning electron microscopy and water contact angle (WCA) analysis methods, respectively. All the nanostructures grown on glass with various buffer layers exhibited strong growth orientation along the (1 0 1) plane. The nature of the buffer layer was found to have remarkable effect on the morphology and wettability of the ZnO nanostructures. Whether the buffer layers were hydrophilic or low hydrophobic, all the ZnO nanostructures grown on the various buffer layers showed high hydrophobic property, and that grown on the AZO buffer layer even exhibited superhydrophobicity with a WCA of 151.1. This work may provide a scientific basis for self-cleaning ZnO-based optoelectronic device applications.

Li, Bao-jia; Huang, Li-jing; Zhou, Ming; Ren, Nai-fei

2013-12-01

286

Capillary Adhesion at the Nanometer Scale  

E-print Network

Molecular dynamics simulations are used to study the capillary adhesion from a nonvolatile liquid meniscus between a spherical tip and a flat substrate. The atomic structure of the tip, the tip radius, the contact angles of the liquid on the two surfaces, and the volume of the liquid bridge are varied. The capillary force between the tip and substrate is calculated as a function of their separation h. The force agrees with continuum predictions for h down to ~ 5 to 10nm. At smaller h, the force tends to be less attractive than predicted and has strong oscillations. This oscillatory component of the capillary force is completely missed in the continuum theory, which only includes contributions from the surface tension around the circumference of the meniscus and the pressure difference over the cross section of the meniscus. The oscillation is found to be due to molecular layering of the liquid confined in the narrow gap between the tip and substrate. This effect is most pronounced for large tip radii and/or smooth surfaces. The other two components considered by the continuum theory are also identified. The surface tension term, as well as the meniscus shape, is accurately described by the continuum prediction for h down to ~ 1nm, but the capillary pressure term is always more positive than the corresponding continuum result. This shift in the capillary pressure reduces the average adhesion by a factor as large as 2 from its continuum value and is found to be due to an anisotropy in the pressure tensor. The cross-sectional component is consistent with the capillary pressure predicted by the continuum theory (i.e., the Young-Laplace equation), but the normal pressure that determines the capillary force is always more positive than the continuum counterpart.

Shengfeng Cheng; Mark O. Robbins

2014-03-18

287

Capillary electrochromatography with macroporous particles.  

PubMed

The performance of macro-porous particles in capillary electrochromatography is studied. Three reversed-phase stationary phases with pore diameters between 500 A and 4000 A have been tested for separation efficiency and mobile phase velocity. With these stationary phases, a large portion of the total flow appears to be through the pores of particles, thereby increasing the separation efficiency through a further decrease of the flow inhomogeneity and through enhancement of the mass transfer kinetics. The effects of pore size and mobile phase composition on the plate height and mobile phase velocity have been studied. With increasing buffer concentrations and larger pore diameters, higher mobile phase velocities and higher separation efficiencies have been obtained. Columns packed with 7 microns particles containing pores with a diameter of 4000 A generated up to 430,000 theoretical plates/m for retained compounds. Reduced plate heights as low as 0.34 have been observed, clearly demonstrating that a significant portion of the flow is through the pores. For the particles containing 4000 A pores no minimum was observed in the H-u plot up to linear velocities of 3.3 mm/s, suggesting that the separation efficiency is dominated by axial diffusion. On relatively long (72 cm) columns, efficiencies of up to 230,000 theoretical plates/column have been obtained under non-optimal running conditions. On short (8.3 cm) columns fast separations could be performed with approximately 15,000 theoretical plates generated in less than 30 s. PMID:10486711

Stol, R; Kok, W T; Poppe, H

1999-08-20

288

Capillary fracture of soft gels.  

PubMed

A liquid droplet resting on a soft gel substrate can deform that substrate to the point of material failure, whereby fractures develop on the gel surface that propagate outwards from the contact line in a starburst pattern. In this paper, we characterize (i) the initiation process, in which the number of arms in the starburst is controlled by the ratio of the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L[proportional]t(3/4). We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent. PMID:24229192

Bostwick, Joshua B; Daniels, Karen E

2013-10-01

289

[Serum protein electrophoresis: comparison of capillary zone electrophoresis Capillarys (Sebia) and agarose gel electrophoresis Hydrasys (Sebia)].  

PubMed

Since several years, serum proteins electrophoresis became a routine analysis, mainly performed by agarose gel electrophoresis, frequently semi-automated. We compared the new fully automated capillary electrophoresis system from Sebia, Capillarys, with our reference method, agarose gel electrophoresis Hydrasys (Sebia). This study focused on the evaluation of both the analytical performances and some practical aspects such as ease of use, rapidity, costs. It appears clearly from that study that both methods give similar results for the detection of monoclonal proteins. We notice that the capillary electrophoresis (Capillarys) displays higher sensitivity (97.2%) than the agarose gel electrophoresis Hydrasys (93.5%), however with a lower specificity (93.7 versus 98.9%). On the other hand, the Capillarys method displays obvious practical advantages such as full automation, ease of use and rapidity. PMID:14671753

Lissoir, B; Wallemacq, P; Maisin, D

2003-01-01

290

High speed and reproducible analysis of nitrosamines by capillary electrophoresis with a sulfonated capillary.  

PubMed

Recently environmental control is regarded as important for good human health conditions, and toxic substances, including carcinogens and endocrine disruptors should be eliminated from our living environment. Hence easy quantitative methods are expected for a high level of environmental control. Our previous paper describes an easy quantitative analysis of nitrosamines (NAs) by capillary electrophoresis with an untreated fused silica capillary installed in an ordinary apparatus. In this paper, utilizing a novel type capillary column having sulfonated inner wall was investigated for improvements of separation performance and reproducibility. A sulfonated capillary causes fast and stabile electroosmotic flow because its inner wall is strongly negative charged. On a performance comparison of a sulfonated capillary with an untreated fused silica, analysis time reduction of c.a. forty percent was achieved, and relative standard deviations of migration times and peak responses were less than one third. In addition sample concentrations giving detection and quantitation limits were also reduced to a half. PMID:17898509

Taga, Atsushi; Nishi, Tomoko; Honda, Yoshitaka; Sato, Atsushi; Terashima, Hiroyuki; Suzuki, Kentaro; Kodama, Shuji; Boki, Keito

2007-01-01

291

Study of the plasma wave excited by intense femtosecond laser pulses in a dielectric capillary  

NASA Astrophysics Data System (ADS)

Laser wakefield in a gas-filled capillary driven by a 1-TW femtosecond Ti:Sa laser pulse is studied experimentally by observing driving pulse spectrum modifications, which are caused by the combined action of the optical field ionization and the plasma density oscillations. Good agreement between the results of extensive numerical simulations and the experimental data allows us to estimate the accelerating gradients in the wake, which range from 5 to 10 MV/cm for typical experimental conditions.

Eremin, V.; Malkov, Yu.; Korolikhin, V.; Kiselev, A.; Skobelev, S.; Stepanov, A.; Andreev, N.

2012-09-01

292

Choosing Actions  

PubMed Central

Actions that are chosen have properties that distinguish them from actions that are not. Of the nearly infinite possible actions that can achieve any given task, many of the unchosen actions are irrelevant, incorrect, or inappropriate. Others are relevant, correct, or appropriate but are disfavored for other reasons. Our research focuses on the question of what distinguishes actions that are chosen from actions that are possible but are not. We review studies that use simple preference methods to identify factors that contribute to action choices, especially for object-manipulation tasks. We can determine which factors are especially important through simple behavioral experiments. PMID:23761769

Rosenbaum, David A.; Chapman, Kate M.; Coelho, Chase J.; Gong, Lanyun; Studenka, Breanna E.

2013-01-01

293

Restructuring and aging in a capillary suspension  

E-print Network

The rheological properties of capillary suspensions, suspensions with small amounts of an added immiscible fluid, are dramatically altered with the addition of the secondary fluid. We investigate a capillary suspension to determine how the network ages and restructures at rest and under applied external shear deformation. The present work uses calcium carbonate suspended in silicone oil (11 % solids) with added water as a model system. Aging of capillary suspensions and their response to applied oscillatory shear is distinctly different from particulate gels dominated by the van der Waals forces. The suspensions dominated by the capillary force are very sensitive to oscillatory flow, with the linear viscoelastic regime ending at a deformation of only 0.1 % and demonstrating power-law aging behavior. This aging persists for long times at low deformations or for shorter times with a sudden decrease in the strength at higher deformations. This aging behavior suggests that the network is able to rearrange and even rupture. This same sensitivity is not demonstrated in shear flow where very high shear rates are required to rupture the agglomerates returning the apparent viscosity of capillary suspensions to the same viscosity as for the pure vdW suspension. A transitional region is also present at intermediate water contents wherein the material response depends very strongly on the type, strength, and duration of the external forcing.

Erin Koos; Wolfgang Kannowade; Norbert Willenbacher

2014-10-07

294

Capillary flow of oil in a single foam microchannel.  

PubMed

When using appropriate surfactants, oil and aqueous foam can be intimately mixed without the foam being destroyed. In this Letter, we show that a foam, initially free of oil, can draw an oil drop under the action of capillary forces and stretch it through the aqueous network. We focus on the suction of oil by a single horizontal foam channel, known as a Plateau border. In such confined channels, imbibition dynamics are governed by a balance between capillarity and viscosity. Yet, the scaling law for our system differs from that of classical imbibition in porous media such as aqueous foam. This is due to the particular geometry of the liquid channels: Plateau borders filled with foaming solution are always concave whereas they can be convex or flat when filled with oil. Finally, the oil slug, confined in the Plateau border, fragments into droplets following a film breakup. PMID:24476278

Piroird, Keyvan; Lorenceau, lise

2013-12-01

295

Capillary Flow of Oil in a Single Foam Microchannel  

NASA Astrophysics Data System (ADS)

When using appropriate surfactants, oil and aqueous foam can be intimately mixed without the foam being destroyed. In this Letter, we show that a foam, initially free of oil, can draw an oil drop under the action of capillary forces and stretch it through the aqueous network. We focus on the suction of oil by a single horizontal foam channel, known as a Plateau border. In such confined channels, imbibition dynamics are governed by a balance between capillarity and viscosity. Yet, the scaling law for our system differs from that of classical imbibition in porous media such as aqueous foam. This is due to the particular geometry of the liquid channels: Plateau borders filled with foaming solution are always concave whereas they can be convex or flat when filled with oil. Finally, the oil slug, confined in the Plateau border, fragments into droplets following a film breakup.

Piroird, Keyvan; Lorenceau, lise

2013-12-01

296

Muscle-Specific Vascular Endothelial Growth Factor Deletion Induces Muscle Capillary Rarefaction Creating Muscle Insulin Resistance  

PubMed Central

Muscle insulin resistance is associated with a reduction in vascular endothelial growth factor (VEGF) action and muscle capillary density. We tested the hypothesis that muscle capillary rarefaction critically contributes to the etiology of muscle insulin resistance in chow-fed mice with skeletal and cardiac muscle VEGF deletion (mVEGF?/?) and wild-type littermates (mVEGF+/+) on a C57BL/6 background. The mVEGF?/? mice had an ?60% and ?50% decrease in capillaries in skeletal and cardiac muscle, respectively. The mVEGF?/? mice had augmented fasting glucose turnover. Insulin-stimulated whole-body glucose disappearance was blunted in mVEGF?/? mice. The reduced peripheral glucose utilization during insulin stimulation was due to diminished in vivo cardiac and skeletal muscle insulin action and signaling. The decreased insulin-stimulated muscle glucose uptake was independent of defects in insulin action at the myocyte, suggesting that the impairment in insulin-stimulated muscle glucose uptake was due to poor muscle perfusion. The deletion of VEGF in cardiac muscle did not affect cardiac output. These studies emphasize the importance for novel therapeutic approaches that target the vasculature in the treatment of insulin-resistant muscle. PMID:23002035

Bonner, Jeffrey S.; Lantier, Louise; Hasenour, Clinton M.; James, Freyja D.; Bracy, Deanna P.; Wasserman, David H.

2013-01-01

297

EFFECT OF RUST ON THE WETTABILITY OF STEEL BY WATER W. Lu and D.D.L. Chung1  

E-print Network

EFFECT OF RUST ON THE WETTABILITY OF STEEL BY WATER W. Lu and D.D.L. Chung1 Composite Materials December 15, 1997; in final form February 6, 1998) ABSTRACT Rust, as formed on steel by immersion of low that rust which is well-adhered to the underlying steel helps the bond between steel rebar and concrete (2

Chung, Deborah D.L.

298

Novel micromirror for vertical optical path conversion formed in silica-based PLC using wettability control of resin  

Microsoft Academic Search

A novel technique has been developed for fabricating a micromirror in a single-mode silica-based planar lightwave circuit (PLC), in which the flat slope for the mirror is made of resin by utilizing wettability control and the surface tension effect. It was shown that the mirror could be designed by numerical calculation based on the equation of Young and Laplace for

Hiroshi Terui; Keizo Shutoh

1998-01-01

299

WATER RESOURCES RESEARCH, VOL. , NO. , PAGES 110, The Impact of Wettability Alteration on Two-Phase Flow  

E-print Network

WATER RESOURCES RESEARCH, VOL. , NO. , PAGES 1­10, The Impact of Wettability Alteration on Two, Sultan Qaboos University, Al-Khoudh, Oman Tad W. Patzek Department of Civil and Environmental Engineering (NAPLs) and gases that co-exist with water in soils and rocks, is of fundamental interest to subsurface

Patzek, Tadeusz W.

300

Calcination-free micropatterning of rare-earth-ion-doped nanoparticle films on wettability-patterned surfaces of plastic sheets.  

PubMed

We demonstrate a patterning technique of rare-earth-ion-doped (RE) nanoparticle films directly on wettability-patterned surfaces fabricated on plastic sheets in one step. Self-assembled monolayers consisting of silane-coupling agent with hydrophobic groups were fabricated on plastic sheets. UV-ozone treatments were performed through a metal mask to selectively remove the self-assembled monolayers in a patterned manner, resulting in the formation of wettability-patterned surfaces on plastic sheets. Using a water dispersion of Er(3+) and Yb(3+)-codoped Y2O3 nanoparticles at a diameter of 100 nm, RE-nanoparticle films were fabricated on the wettability-patterned surfaces by a dip-coating technique. By adjusting the concentration of RE-nanoparticle dispersion, withdrawal speed, and withdrawal angle, amount of RE-nanoparticles, we were able to control the structures of the RE-nanoparticle films. Fluorescence microscope observations demonstrate that visible upconversion luminescence and near-infrared fluorescence were emitted from the RE-nanoparticle films on the wettability-patterned surfaces. This technique allows for the fabrication of flexible emitting devices with long-operating life time with minimized material consumption and few fabrication steps, and for the application to sensors, emitting devices, and displays in electronics, photonics, and bionics in the future. PMID:24655829

Watanabe, Satoshi; Hamada, Yudai; Hyodo, Hiroshi; Soga, Kohei; Matsumoto, Mutsuyoshi

2014-05-15

301

Are courageous actions successful actions?  

Microsoft Academic Search

When asked to describe a courageous action they have taken personally, people overwhelmingly describe an action with a successful outcome (Pury, Kowalski, & Spearman, 2007). Study 1 replicated these findings in observations of other people. Fifty participants described a courageous action taken by another person and made parallel ratings to Pury et al. Participants in Study 1 also described actions

Cynthia L. S. Pury; Autumn D. Hensel

2010-01-01

302

Novel absorption detection techniques for capillary electrophoresis  

SciTech Connect

Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the {mu}M level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

Xue, Y.

1994-07-27

303

Extragingival pyogenic granuloma histologically mimicking capillary hemangioma  

PubMed Central

Pyogenic granuloma is a tumor-like proliferation to a non-specific infection. The tumor-like growth is considered to be non-neoplastic in nature and presents in various clinical and histological forms in the oral cavity. Hemangiomas are benign vascular anomalies characterized by benign proliferation of blood vessels. The aim of this article is to drive attention toward the uncommon location of capillary hemangioma on the palate. In spite of their benign nature, intraoral capillary hemangiomas are always clinically important to be diagnosed well in time and suitably managed. The lesion in the present case although clinically diagnosed as pyogenic granuloma gave a histological picture of capillary hemangioma when surgically excised.

Dahiya, Ritu; Kathuria, Abhinav

2014-01-01

304

Electromagnetically-driven capillary switches and oscillators  

NASA Astrophysics Data System (ADS)

By designing pinned-contact, coupled droplet pairs at the appropriate length scale to promote surface tension as the dominant force, one can create bi-stable capillary switches and natural oscillators. These systems have been triggered by pressure pulses, electrochemistry, and electroosmosis. These methods are typically accompanied by bulky setups or slow response times. An alternate approach exploits electromagnetic activation. Our device consists of a millimeter scale orifice, overfilled with an aqueous ferrofluid, in proximity to a wire coil that generates a magnetic field. Experimental evidence of such capillary switches and energy efficient oscillators is presented here. Comparisons to a simplified model are also presented. This activation method is shown to have relatively fast response times, low driving voltages, and individual addressability. Electromagnetically activated capillary switches and oscillators offer many applications ranging from high-speed adaptive optics to micro-actuators, with possible circuit board integration.

Malouin, Bernard; Hirsa, Amir; Vogel, Michael

2009-11-01

305

The Roles of Titanium Surface Micro/Nanotopography and Wettability on the Differential Response of Human Osteoblast Lineage Cells  

PubMed Central

Surface micro and nanostructural modifications of dental and orthopaedic implants have shown promising in vitro, in vivo, and clinical results. Surface wettability has also been suggested to play an important role in osteoblast differentiation and osseointegration. However, the available techniques to measure surface wettability are not reliable on clinically-relevant, rough surfaces. Furthermore, how the differentiation state of osteoblast lineage cells impacts their response to micro/nanostructured surfaces, and the role of wettability on this response, remains unclear. In the current study, surface wettability analyses (optical sessile drop analysis, ESEM analysis, and the Wilhelmy technique) indicated hydrophobic static responses for deposited water droplets on microrough and micro/nanostructured specimens, while hydrophilic responses were observed with dynamic analyses of micro/nanostructured specimens. The maturation and local factor production of human immature osteoblast-like MG63 cells was synergistically influenced by nanostructures superimposed onto microrough titanium (Ti) surfaces. In contrast, human mesenchymal stem cells (MSCs) cultured on micro/nanostructured surfaces in the absence of exogenous soluble factors, exhibited less robust osteoblastic differentiation and local factor production compared to cultures on unmodified microroughened Ti. Our results support previous observations using Ti6Al4V surfaces showing that recognition of surface nanostructures and subsequent cell response is dependent on the differentiation state of osteoblast lineage cells. The results also indicate that this effect may be partly modulated by surface wettability. These findings support the conclusion that the successful osseointegration of an implant depends on contributions from osteoblast lineage cells at different stages of osteoblast commitment. PMID:23232211

Gittens, Rolando A.; Olivares-Navarrete, Rene; Cheng, Alice; Anderson, David M.; McLachlan, Taylor; Stephan, Ingrid; Geis-Gerstorfer, Jurgen; Sandhage, Kenneth H.; Fedorov, Andrei G.; Rupp, Frank; Boyan, Barbara D.; Tannenbaum, Rina; Schwartz, Zvi

2013-01-01

306

Observation of gravity-capillary wave turbulence.  

PubMed

We report the observation of the crossover between gravity and capillary wave turbulence on the surface of mercury. The probability density functions of the turbulent wave height are found to be asymmetric and thus non-Gaussian. The surface wave height displays power-law spectra in both regimes. In the capillary region, the exponent is in fair agreement with weak turbulence theory. In the gravity region, it depends on the forcing parameters. This can be related to the finite size of the container. In addition, the scaling of those spectra with the mean energy flux is found in disagreement with weak turbulence theory for both regimes. PMID:17359160

Falcon, Eric; Laroche, Claude; Fauve, Stphan

2007-03-01

307

New adsorbed coatings for capillary electrophoresis.  

PubMed

New acrylic polymers bearing oxirane groups were synthesized to be used in the production of coated capillaries. A fully automated coating procedure was devised based on the use of diluted water solutions of these polymers. The whole procedure required less than 30 min. The new polymers rapidly adsorbed from water onto the capillary wall, thus suppressing electroosmotic flow (EOF) to a negligible value. The adsorbed coatings were stable for hundreds of hours at high pH, temperature, and in the presence of 8 M urea. Efficient separations of acidic and basic proteins were achieved in the new phases. PMID:10768776

Chiari, M; Cretich, M; Damin, F; Ceriotti, L; Consonni, R

2000-03-01

308

Observation of gravity-capillary wave turbulence  

E-print Network

We report the observation of the cross-over between gravity and capillary wave turbulence on the surface of mercury. The probability density functions of the turbulent wave height are found to be asymmetric and thus non Gaussian. The surface wave height displays power-law spectra in both regimes. In the capillary region, the exponent is in fair agreement with weak turbulence theory. In the gravity region, it depends on the forcing parameters. This can be related to the finite size of the container. In addition, the scaling of those spectra with the mean energy flux is found in disagreement with weak turbulence theory for both regimes.

Eric Falcon; Claude Laroche; Stphan Fauve

2006-10-11

309

Aptamers in Affinity Separations:Capillary Electrophoresis  

Microsoft Academic Search

\\u000a Assays employing aptamers in capillary electrophoresis (CE), including competitive and noncompetitive assays, fluorescence\\u000a polarization (FP) assays, nonequilibrium capillary electrophoresis of equilibrium mixtures, and affinity-polymerase chain\\u000a reaction-CE assays, are summarized. These assays can be used to estimate dissociation rate and equilibrium binding constants,\\u000a determine binding stoichiometries, study molecular interactions, and quantitatively determine specific analytes (e.g., proteins)\\u000a in complex media. They can

Jeffrey W. Guthrie; Yuanhua Shao; X. Chris Le

310

Motion of a Drop on a Solid Surface Due to a Wettability Gradient  

NASA Technical Reports Server (NTRS)

The hydrodynamic force experienced by a spherical-cap drop moving on a solid surface is obtained from two approximate analytical solutions and used to predict the quasi-steady speed of the drop in a wettability gradient. One solution is based on approximation of the shape of the drop as a collection of wedges, and the other is based on lubrication theory. Also, asymptotic results from both approximations for small contact angles, as well as an asymptotic result from lubrication theory that is good when the length scale of the drop is large compared with the slip length, are given. The results for the hydrodynamic force also can be used to predict the quasi-steady speed of a drop sliding down an incline.

Subramanian, R.; Moumen, Nadjoua; McLaughlin, John B.

2005-01-01

311

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

312

On the effect of surface roughness height, wettability, and nanoporosity on Leidenfrost phenomena  

NASA Astrophysics Data System (ADS)

In recent quenching heat transfer studies of nanofluids, it was found that deposition of nanoparticles on a surface raises its Leidenfrost point (LFP) considerably [Kim et al., Int. J. Multiphase Flow 35, 427 (2009) and Kim et al., Int. J. Heat Mass Transfer 53, 1542 (2010)]. To probe the physical mechanism underlying this observation, the effects of surface properties on LFP of water droplets were studied, using custom-fabricated surfaces for which roughness height, wettability, and porosity were controlled at the nanoscale. This approach reveals that nanoporosity is the crucial feature in efficiently increasing the LFP by initiating heterogeneous nucleation of bubbles during short-lived solid-liquid contacts, which results in disruption of the vapor film.

Kim, Hyungdae; Truong, Bao; Buongiorno, Jacopo; Hu, Lin-Wen

2011-02-01

313

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

314

Growing hydrophobicity on a smooth copper oxide thin film at room temperature and reversible wettability transition  

NASA Astrophysics Data System (ADS)

The thin CuO film is acquired by a quick dip of copper in H2O2 solutions at room temperature. The CuO film appears smooth and exhibits superhydrophilic nature. The composition change cannot be verified by X-ray photoelectron spectroscopy but can be manifested by the water contact angle. In the ambient condition, the thickness of the oxidized layer and the surface hydrophobicity grow gradually, while the chemical composition of the overall oxidized film remains essentially unchanged. In the vacuum, the growth rate of the hydrophobicity is significantly elevated, revealing deoxidation on the upmost surface. Our results indicate that growing hydrophobicity on the CuO film is spontaneous and the reversible wettability transition can be observed by H2O2 oxidation and vacuum deoxidation.

Tu, Sheng-Hung; Wu, Hsing-Chen; Wu, Cyuan-Jhang; Cheng, Shao-Liang; Sheng, Yu-Jane; Tsao, Heng-Kwong

2014-10-01

315

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

2013-06-01

316

Easy route to the wettability cycling of copper surface between superhydrophobicity and superhydrophilicity.  

PubMed

A hierarchical copper structure combining micro- and nanogaps/pores was built up on copper substrate by etching and electrodeposition. The fresh as-deposited copper was easily oxidized in air at room temperature, forming a CuO layer covering on the surface. The surface could be hydrophobized with thiol-modified fluorocarbons, after which it showed a water contact angle as high as 165 2. This surface could also regain the superhydrophilicity with a zero water contact angel after annealing at 200 C for 10 min to desorb the low surface energy monolayer of thiol-modified fluorocarbons and reform a CuO layer again on the surface. Repeating the process of adsorption/desorption of the monolayer by modification and annealing, it was successful to fulfill the wettability cycling between superhydrophobicity and superhydrophilicity on the copper surface. The adsorption and desorption mechanism of the monolayer was discussed based on the result of surface chemistry analysis. PMID:22148586

Wang, Guoyong; Zhang, Tong-Yi

2012-01-01

317

Investigation of antibacterial and wettability behaviours of plasma-modified PMMA films for application in ophthalmology  

NASA Astrophysics Data System (ADS)

The main objective of this research is the experimental investigation of the surface properties of polymethyl methacrylate (PMMA) such as wettability and the roughness effect on Escherichia coli (gram negative) cell adhesion. Radio frequency (RF; 13.56 MHz) oxygen plasma was used to enhance the antibacterial and wettability properties of this polymer for biomedical applications, especially ophthalmology. The surface was activated by O2 plasma to produce hydrophilic functional groups. Samples were treated with various RF powers from 10 to 80 W and different gas flow rates from 20 to 120 sccm. Optical emission spectroscopy was used to monitor the plasma process. The modified surface hydrophilicity, morphology and transparency characteristics were studied by water contact angle measurements, atomic force microscopy and UV-vis spectroscopy, respectively. Based on the contact angle measurements of three liquids, surface free energy variations were investigated. Moreover, the antibacterial properties were evaluated utilizing the method of plate counting of Escherichia coli. Also, in order to investigate stability of the plasma treatment, an ageing study was carried out by water contact angle measurements repeated in the days after the treatment. For biomedical applications, especially eye lenses, highly efficient antibacterial surfaces with appropriate hydrophilicity and transparency are of great importance. In this study, it is shown that the plasma process is a reliable and convenient method to achieve these purposes. A significant alteration in the hydrophilicity of a pristine PMMA surface was observed after treatment. Also, our results indicated that the plasma-modified PMMAs exhibit appropriate antibacterial performance. Moreover, surface hydrophilicity and surface charge have more influence on bacterial adhesion rate than surface roughness. UV-vis analysis results do not show a considerable difference for transparency of samples after plasma treatment.

Rezaei, Fatemeh; Abbasi-Firouzjah, Marzieh; Shokri, Babak

2014-02-01

318

A Process for Producing Highly Wettable Aluminum 6061 Surfaces Compatible with Hydrazine  

NASA Technical Reports Server (NTRS)

NASA's Global Precipitation Measurement (GPM) mission is an ongoing Goddard Space Flight Center (GSFC) project whose basic objective is to improve global precipitation measurements. The space-based portion of the mission architecture consists of a primary or core spacecraft and a constellation of NASA and contributed spacecrafts. The efforts described in this paper refer to the core spacecraft (hereafter referred to as simply GPM) which is to be fabricated at GSFC. It has been decided that the GPM spacecraft is to be a "design-for-demise-spacecraft." This requirement resulted in the need for a propellant tank that would also demise or ablate to an appropriate degree upon re-entry. Composite overwrapped aluminum lined propellant tanks with aluminum propellant management devices (PMD) were shown by analyses to demise and thus became the baseline configuration for GPM. As part of the GPM tank development effort, long term compatibility and wettability testing with hydrazine was performed on Al6061 and 2219 coupons fabricated and cleaned by conventional processes. Long term compatibility was confirmed. However, the wettability of the aluminum as measured by contact angle produced higher than desired angles (greater than 30 deg.) with excessive scatter. The availability of PMD materials exhibiting consistently low contact angles aids in the design of simple PMDs. Two efforts performed by Angeles Crest Engineering and funded by GSFC were undertaken to reduce the risk of using aluminum for the GPM PMD. The goal of the first effort was to develop a cleaning or treatment process to produce consistently low contact angles. The goal of the second effort was to prove via testing that the processed aluminum would retain compatibility with hydrazine and retain low contact angle after long term exposure to hydrazine. Both goals were achieved. This paper describes both efforts and the results achieved.

Moore, N. R.; Ferraro, N. W.; Yue, A. F.; Estes, R. H.

2007-01-01

319

Electrochromic performance, wettability and optical study of copper manganese oxide thin films: Effect of annealing temperature  

NASA Astrophysics Data System (ADS)

In the present work, the nanostructured copper manganese oxide (CMO) thin films were prepared from acetate based sol-gel precursors and deposited on glass and indium tin oxide (ITO) substrates by dip-coating technique. The films were annealed at 300, 400 and 500 C in ambient atmosphere. The effects of annealing temperature on structural, morphological, wettability, electrochromic and optical properties of CMO thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDX), water contact angle measurement (WCA), cyclic voltammetry (CV) measurements and ultraviolet-visible (UV-vis) spectrophotometery. The presence of mixed oxide phases comprising of copper manganese oxide (CuMn2O4) and manganese oxide at different annealing temperature was confirmed by XRD patterns. The results showed that the Mn3O4 phase has been changed to Mn2O3 when the annealing temperature is increased from 300 to 500 C. The FESEM images indicated that the granular surface morphology was sensitive to annealing temperature. EDX studies indicated that the thin films contained O, Mn and Cu species. Wettability studies showed that the water contact angle of the nanostructured CMO thin films coated on glass substrates was influenced by the variation of annealing temperature and the surface nature of thin films was changed from hydrophilic to hydrophobic. The results of CVs measurement indicated that the anodic and cathodic charge density and capacitance of all CMO samples decreased with increasing scan rate in potential range of -1-1 eV. Also, the annealed CMO thin film at 500 C showed better electrochromic performance with respect to other samples at lower scan rate. The thickness, refractive index, extinction coefficient and optical band gap of thin films coated on glass substrates were calculated from reflectance and transmittance spectra using an iterative numerical method. The optical band gap of nanostructured CMO thin films increased with increasing annealing temperature.

Falahatgar, S. S.; Ghodsi, F. E.; Tepehan, F. Z.; Tepehan, G. G.; Turhan, ?.

2014-01-01

320

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. 13 figs.

Linehan, J.C.; Yonker, C.R.; Zemanian, T.S.; Franz, J.A.

1995-11-21

321

PERFORMANCE OF CAPILLARY DISCHARGE GUIDED LASER PLASMA WAKEFIELD ACCELERATOR  

E-print Network

PERFORMANCE OF CAPILLARY DISCHARGE GUIDED LASER PLASMA WAKEFIELD ACCELERATOR K. Nakamura , E of the capillary discharge guided laser plasma wakefield accelerator with a capillary of 225 m diameter and 33 mm beam divergence. INTRODUCTION The plasma-based accelerator [1] has attracted a lot of attention since

Geddes, Cameron Guy Robinson

322

Capillary optical guiding experiments for the NRL laser wakefield accelerator  

Microsoft Academic Search

Extended propagation of terawatt (TW) laser pulses has been shown in plasma channels formed with a capillary discharge. Capillary optical guiding experiments at NRL utilize plasma channels formed using both laser ablation and electrical discharge. Present experiments aim to develop laser preionization and ablation from capillary walls as a formation technique for the guiding plasma. Electron density measurements of laser-formed

T. G. Jones; C. I. Moore; A. Ting; P. Sprangle; D. Kaganovich; K. Krushelnick

2001-01-01

323

NRL Capillary Optical Guiding Experiments for Laser Plasma Accelerators  

Microsoft Academic Search

Extended propagation of TW laser pulses has been shown in plasma channels formed with a capillary discharge.( D. Kaganovich, et al., Phys. Rev. E 59) R4769 (1999). Capillary optical guiding experiments at NRL utilize plasma channels formed using both laser preionization and electrical discharge. Present experiments aim to characterize plasma channel conditions within the capillary, and to optimize plasma conditions

T. G. Jones; C. I. Moore; A. Ting; R. Hubbard; P. Sprangle; D. Kaganovich; A. Ziegler; K. Krushelnick

2000-01-01

324

Capillary forces and osmotic gradients in salt water -oil systems  

E-print Network

Capillary forces and osmotic gradients in salt water - oil systems Georg Ellila Chemical study. This is to my knowledge the first time the transport mechanisms in capillary oil-salt water and the Vista Program. 1 #12;Abstract This project looks at the capillary systems with salt water and oil

Kjelstrup, Signe

325

Development of capillary optics for microbeam applications with synchrotron radition  

Microsoft Academic Search

Capillary optics have been suggested some time ago to confine x-ray beams to the size of a few microns. First experiments using glass capillaries of various sizes and shapes have been reported recently. We discuss the design and fabrication of capillary optics at CHESS, the Cornell High Energy Synchrotron Source, for applications such as Laue diffraction, x-ray fluorescence, and small

Reinhard Pahl; Donald H. Bilderback

1996-01-01

326

Gravity-driven slug motion in capillary tubes  

Microsoft Academic Search

The velocity of a liquid slug falling in a capillary tube is lower than predicted for Poiseuille flow due to presence of menisci, whose shapes are determined by the complex interplay of capillary, viscous, and gravitational forces. Due to the presence of menisci, a capillary pressure proportional to surface curvature acts on the slug and streamlines are bent close to

Ivan Lunati; Dani

2009-01-01

327

EXPERIMENTAL MEASUREMENTS OF CAPILLARY PRESSURE AND RELATIVE PERMEABILITY HYSTERESIS  

Microsoft Academic Search

Capillary pressure and relative permeability hysteresis have been investigated on core samples with different wetting characteristics. The relative permeability and capillary pressure curves depend on the direction of saturation changes and on the maximum and minimum achieved saturations. A conceptual model to explain the hysteresis trends in both the relative permeability and capillary pressure is presented. The model attributes hysteresis

Shehadeh K. Masalmeh

328

Transverse Diffusion of Laminar Flow Profiles To Produce Capillary Nanoreactors  

E-print Network

for mixing two or more reactants inside capillaries. Conceptually, solutions of reactants are injected inside the capillary by pressure as a series of consecutive plugs. Due to the laminar nature of flow inside mixtures inside the capillary, TDLFP lowers reagent consumption to nanoliters (microliters are required

Krylov, Sergey

329

Prolactin actions.  

PubMed

Molecular genetics and other contemporary approaches have contributed to a better understanding of prolactin (PRL) actions at the cellular and organismal levels. In this review, several advances in knowledge of PRL actions are highlighted. Special emphasis is paid to areas of progress with consequences for understanding of human PRL actions. The impacts of these advances on future research priorities are analyzed. PMID:24130130

Horseman, Nelson D; Gregerson, Karen A

2014-02-01

330

Design criteria for SW-205 capillary system  

SciTech Connect

This design criteria covers the converting of the SW-250 Capillary System from fumehood manual operation to sealed glovebox automated operation. The design criteria contains general guidelines and includes drawings reflecting a similar installation at another site. Topics include purpose and physical description, architectural-engineering requirements, reference document, electrical, fire protection, occupational safety and health, quality assurance, and security.

Lyons, W.J.

1989-04-01

331

Modeling Microscopic Chemical Sensors in Capillaries  

Microsoft Academic Search

Nanotechnology-based microscopic robots could provide accurate in vivo measurement of chemicals in the bloodstream for detailed biological research and as an aid to medical treatment. Quantitative perfor- mance estimates of such devices require models of how chemicals in the blood diffuse to the devices. This paper models microscopic robots and red blood cells (erythrocytes) in capillaries using realistic distorted cell

Tad Hogg

2008-01-01

332

Derive capillary pressure from well logs  

SciTech Connect

A new approach has been developed to estimate in-situ capillary pressure and relative permeability characteristics in the transition zone. The technique is based on incorporating petrophysical data measured on core samples with well log analysis. Relative permeability can be determined for both drainage and inhibition conditions using the matched capillary pressure data. A technique has been developed to extrapolate petro-physical data where core data is absent or not representative of in-situ conditions. It is based on using log data to derive a water saturation vs. depth profile in the transition zone of the formation of interest. The log-derived water saturation distribution is then correlated to generalized capillary pressure curves typical of the formation studied. The capillary pressure type curves are generated from available core data and other petrophysical information. Relative permeability curves are then generated using correlations based on Purcell's model. The technique can be used in multi-layered and homogeneous reservoirs provided that one homogeneous layer is at least 20 ft thick.

Ibrahim, A. (Suez Canal Univ. (Egypt)); Desbrandes, R.; Bassiouni, Z. (Louisiana State Univ., Baton Rouge, LA (United States))

1994-07-01

333

A novel capillary polymerase chain reaction machine  

E-print Network

I built a novel prototype capillary polymerase chain reaction machine. The purpose was to perform a single reaction as fast as possible with a reaction volume - 100 nl. The PCR mix is in the form of a 1 /1 droplet that ...

Chiou, Jeffrey Tsungshuan

2001-01-01

334

Using Capillary Flows to Pattern Lines  

NASA Astrophysics Data System (ADS)

One can appreciate how capillary forces cause unexpected patterns and shapes by looking at a soap bubble. Pattern formation by surface tension is seen in ring patterns of coffee stains, fingering patterns in Hele-Shaw cells, ordering of two dimensional micro-sphere crystals, combing of DNA and skeleton formation in marine creatures called radiolarians. Though comman, problems involving the understanding and control of the self-assembly mechanism need to be resolved before using capillary forces as a practical lithographic tool. Here, we report capillary flows create line patterns in evaporating liquids between closely spaced parallel plates. The widths of these lines range from a few microns to a few nanometers. Deliberate patterning of such lines requires pinning of the contact line and the presence of foaming surfactants. The position and type of line can be controlled with artificial pinning points and varying solutes respectively, and large-scale photolithography can be used to guide and control the definition of nanostructures. We provide ``proof of principle'' demonstrations of this method's application by creating lines of colloidal quantum dots and micro-spheres. This represents the first step in using capillary phenomena to create controlled, self--assembling, one-dimensional wire-like structures

Vyawahare, Saurabh; Craig, Kate; Scherer, Axel

2006-03-01

335

Enantiomeric resolution study by capillary electrophoresis  

Microsoft Academic Search

The enantiomeric separation of several arylpropionic acids, namely carprofen, cicloprofen, flurbiprofen, ibuprofen, indoprofen, ketoprofen, naproxen and suprofen has been studied by capillary zone electrophoresis using different chiral selectors added to the background electrolyte with the aim to find the optimum experimental conditions for both qualitative and quantitative purposes. The chiral selectors used included two ?-cyclodextrin derivatives and a glycosidic antibiotic,

Salvatore Fanali; Claudia Desiderio; Zeineb Aturki

1997-01-01

336

Crystalline Order on Catenoidal Capillary Bridges  

E-print Network

We study the defect structure of crystalline particle arrays on negative Gaussian curvature capillary bridges with vanishing mean curvature (catenoids). The threshold aspect ratio for the appearance of isolated disclinations is found and the optimal positions for dislocations determined. We also discuss the transition from isolated disclinations to scars as particle number and aspect ratio are varied.

Mark J. Bowick; Zhenwei Yao

2010-12-20

337

Mach-like capillary-gravity wakes  

E-print Network

We determine experimentally the angle $\\alpha$ of maximum wave amplitude in the far-field wake behind a vertical surface-piercing cylinder translated at constant velocity $U$ for Bond numbers $Bo_D = D / \\lambda_c$ ranging between 0.1 and 4.2, where $D$ is the cylinder diameter and $\\lambda_c$ the capillary length. In all cases the wake angle is found to follow a Mach-like law at large velocity, $\\alpha \\sim U^{-1}$, but with different scalings depending on the value of $Bo_D$. For small $Bo_D$ (large capillary effects), the wake angle approximately follows the law $\\alpha \\simeq c_{\\rm g,min} / U$, where $c_{\\rm g,min}$ is the minimum group velocity of capillary-gravity waves. For larger $Bo_D$ (weak capillary effects), we recover at large velocity the law $\\alpha \\sim \\sqrt{gD}/U$ recently found for ship wakes [Rabaud and Moisy, "Ship Wakes: Kelvin or Mach Angle?", Phys. Rev. Lett. {\\bf 110}, 214503 (2013)]. Using the general property of dispersive waves that the characteristic wavelength of the wavepacket ...

Moisy, F

2014-01-01

338

Capillary electrophoretic determination of sulfite using the zone-passing technique of in-capillary derivatization  

Microsoft Academic Search

A new capillary electrophoretic (CE) method was developed for the simple and selective determination of sulfite. The proposed method is based on the in-capillary derivatization of sulfite with iodine using the zone-passing technique and direct UV detection of iodide formed. The optimal conditions for the separation and derivatization reaction were established by varying concentration of iodine, electrolyte pH and applied

Giedre Jankovskiene; Zydrunas Daunoravicius; Audrius Padarauskas

2001-01-01

339

Dynamics of a capillary invasion in a closed-end capillary.  

PubMed

The position of fluid invasion in an open capillary increases as the square root of time and ceases when the capillary and hydrostatic forces are balanced, when viscous and inertia terms are negligible. Although this fluid invasion into open-end capillaries has been well described, detailed studies of fluid invasion in closed-end capillaries have not been explored thoroughly. Thus, we demonstrated, both theoretically and experimentally, a fluid invasion in closed-end capillaries, where the movement of the meniscus and the invasion velocity are accompanied by adiabatic gas compression inside the capillary. Theoretically, we found the fluid oscillations during invasion at short time scales by solving the one-dimensional momentum balance. This oscillatory motion is evaluated to determine which physical forces dominate the different conditions, and is further described by a damped driven harmonic oscillator model. However, this oscillating motion is not observed in the experiments. This inconsistency is due to the following: first, a continuous decrease in the radius of the curvature caused by decreasing the invasion velocity and increasing pressure inside the closed-end capillary, and second, the shear stress increase in the short time scale by the plug like velocity profile within the entrance length. The viscous term of modified momentum equation can be written as K(8?l/rc(2))(dl/dt) by using the multiplying factor K, which represents the increase of shear stress. The K is 7.3, 5.1, and 4.8 while capillary aspect ratio ?c is 740, 1008, and 1244, respectively. PMID:24984765

Lim, Hosub; Tripathi, Anubhav; Lee, Jinkee

2014-08-12

340

Modelling capillary oxygen supply capacity in mixed muscles: capillary domains revisited.  

PubMed

Developing effective therapeutic interventions for pathological conditions associated with abnormal oxygen transport to muscle fibres critically depends on the objective characterisation of capillarity. Local indices of capillary supply have the potential to identify the onset of fine-scale tissue pathologies and dysregulation. Detailed tissue geometry, such as muscle fibre size, has been incorporated into such measures by considering the distribution of Voronoi polygons (VP) generated from planar capillary locations as a representation of capillary supply regions. Previously, detailed simulations have predicted that this is generally accurate for muscle tissue with uniform oxygen uptake. Here we extend this modelling framework to heterogeneous muscle for the assessment of capillary supply capacity under maximal sustainable oxygen consumption. We demonstrate for muscle with heterogeneous fibre properties that VP theoretically provide a computationally simple but often accurate representation of trapping regions (TR), which are predicted from biophysical transport models to represent the areas of tissue supplied by individual capillaries. However, this use of VP may become less accurate around large fibres, and at the interface of fibres of largely different oxidative capacities. In such cases, TR may provide a more robust representation of capillary supply regions. Additionally, given VP can only approximate oxygen delivery by capillaries, we show that their generally close relationship to TR suggests that (1) fibre type distribution may be tightly regulated to avoid large fibres with high oxidative capacities, (2) the anatomical fibre distribution is also tightly regulated to prevent a large surface area of interaction between metabolically dissimilar fibres, and (3) in chronically hypoxic tissues capillary distribution is more important in determining oxygen supply than the spatial heterogeneity of fibre demand. PMID:24768706

Al-Shammari, Abdullah A; Gaffney, Eamonn A; Egginton, Stuart

2014-09-01

341

Capillary climb dynamics in the limits of prevailing capillary and gravity force  

NASA Astrophysics Data System (ADS)

The dynamics of the capillary climb of a wetting liquid into a porous medium that is opposed by gravity force is studied numerically. The capillary network model, in which an actual porous medium is represented as a network of pores and throats, is used. The numerical results for the capillary climb reveal that there are at least two distinct flow regimes. The first regime is characterized by the capillary force being much larger than the gravity force. In this regime the Washburn solution can be used to predict the changes of climbing height over time. In the second regime the capillary and gravity forces become comparable, and one observes a slower increase in the climbing height as a function of time. The numerical results from this study, expressed as the climbing height as a power law function of time, indicate that the two powers, which correspond to the two distinct regimes, differ significantly. The comparison of the powers with experimental data indicates a good agreement. Furthermore, the power value from the Washburn solution is analyzed, where it should be equal to one half for purely capillary force driven flow. This is in contrast to the value of around 0.43 that is found experimentally. We show from the numerical solution that this discrepancy is due to the momentum dissipation on the liquid interface.

Navaz, H. K.; Markicevic, B.; Bijeljic, B.

2010-11-01

342

Effects of ionic and nonionic surfactants on milk shell wettability during co-spray-drying of whole milk particles.  

PubMed

Mixing surfactants with whole milk feed before spray drying could be a commercially favorable approach to produce instant whole milk powders in a single step. Pure whole milk powders obtained directly from spray drying often have a high surface fat coverage (up to 98%), rendering them less stable during storage and less wettable upon reconstitution. Dairy industries often coat these powders with lecithin, a food-grade surfactant, in a secondary fluidized-bed drying stage to produce instant powders. This study investigated the changes in wetting behavior on the surface of a whole milk particle caused by the addition of surfactants before drying. Fresh whole milk was mixed with 0.1% (wt/wt) Tween 80 or 1% (wt/wt) lecithin (total solids), and the wetting behavior of the shell formed by each sample was captured using a single-droplet drying device at intermediate drying stages as the shell was forming. The addition of surfactants improved shell wettability from the beginning of shell formation, producing more wettable milk particles after drying. The increase in surfactant loading by 10 times reduced the wetting time from around 30s to <5s. At the same loading of 1% (wt/wt; total solids), milk particles with Tween 80 were much more wettable than those with lecithin (<5s compared with >30s). We proposed that Tween 80 could adsorb at the oil-water interface of fat globules, making the surface fat more wettable, whereas lecithin tends to combine with milk proteins to form a complex, which then competes for the air-water surface with fat globules. Spray-drying experiments confirmed the greatly improved wettability of whole milk powders by the addition of either 0.1% (wt/wt) Tween 80 or 1% (wt/wt) lecithin; wetting time was reduced from 354s to <15s. To the best of our knowledge, this is the first time that a dynamic droplet drying system has been used to elucidate the complex interactions between ionic or nonionic surfactants and milk components (both proteins and fat), as well as the resultant effect on the development of milk particle functionality during drying. PMID:24997659

Lallbeeharry, P; Tian, Y; Fu, N; Wu, W D; Woo, M W; Selomulya, C; Chen, X D

2014-09-01

343

Theory and simulation of short intense laser pulse propagation in capillary tubes with wall ablation  

SciTech Connect

The theory and simulations of short intense laser pulses propagating in capillary tubes, whose properties are changed in time and space under the action of the laser field, are presented. A hybrid approach has been used in which the dynamics of fields inside the capillary tube is described analytically, whereas the ionization, heating, and expansion of the plasma created at the inner wall of the tube under the action of the transverse energy flux are calculated by numerical simulation. This hybrid method has allowed to determine the behavior of high laser fluxes guided over large distances. The threshold value for the incident intensity at which plasma creation plays a significant role has been estimated analytically and confirmed by numerical results. For intensities above the threshold, the transmission becomes highly sensitive to the energy of the laser pulse, being minimum at the intensity level for which the electron temperature of the capillary wall slightly exceeds the Fermi level and the electron collision frequency has a maximum.

Veysman, M.; Cros, B.; Andreev, N.E.; Maynard, G. [Laboratoire de Physique des Gaz et des Plasmas, CNRS-Universite Paris Sud 11, 91405 Orsay (France) and Institute for High Energy Densities, Moscow (Russian Federation); Laboratoire de Physique des Gaz et des Plasmas, CNRS-Universite Paris Sud 11, 91405 Orsay (France); Institute for High Energy Densities, Moscow (Russian Federation); Laboratoire de Physique des Gaz et des Plasmas, CNRS-Universite Paris Sud 11, 91405 Orsay (France)

2006-05-15

344

Separate effects of surface roughness, wettability and porosity on boiling heat transfer and critical heat flux and optimization of boiling surfaces  

E-print Network

The separate effects of surface wettability, porosity, and roughness on critical heat flux (CHF) and heat transfer coefficient (HTC) were examined using carefully-engineered surfaces. All test surfaces were prepared on ...

O'Hanley, Harrison Fagan

2012-01-01

345

Improved Modeling and Understanding of Diffusion-Media Wettability on Polymer-Electrolyte-Fuel-Cell Performance  

SciTech Connect

A macroscopic-modeling methodology to account for the chemical and structural properties of fuel-cell diffusion media is developed. A previous model is updated to include for the first time the use of experimentally measured capillary pressure -- saturation relationships through the introduction of a Gaussian contact-angle distribution into the property equations. The updated model is used to simulate various limiting-case scenarios of water and gas transport in fuel-cell diffusion media. Analysis of these results demonstrate that interfacial conditions are more important than bulk transport in these layers, where the associated mass-transfer resistance is the result of higher capillary pressures at the boundaries and the steepness of the capillary pressure -- saturation relationship. The model is also used to examine the impact of a microporous layer, showing that it dominates the response of the overall diffusion medium. In addition, its primary mass-transfer-related effect is suggested to be limiting the water-injection sites into the more porous gas-diffusion layer.

Weber, Adam

2010-03-05

346

Morphological and cytochemical aspects of capillary permeability.  

PubMed

Transport of plasma soluble constituents across the capillary wall is of primordial importance in cardiovascular physiology. While physiological experiments have concluded with the existence of two sets of pores, a large one responsible for the transport of proteins and a small one designed for the diffusion of small solutes, the morphological counterparts have yet to get general agreement. In this review, we present the different proposed paths within and between the endothelial cells that do allow passage of plasma constituents and may respond to the definitions established by physiological means. The vesicular system existing in endothelial cells has been the first transendothelial path to be proposed. Several data have demonstrated the involvement of this system in transport, although others have systematically brought controversy. One alternative to the vesicles has been the demonstration of membrane-bound tubules creating, in certain cases, transendothelial channels that would allow diffusion of plasma proteins and other constituents across the capillary wall. Access to this tubulo-vesicular system could be restrained by the stomatal diaphragm and facilitated by specific membrane receptors. Further, we have demonstrated for the first time with morpho-cytochemical tools, that the intercellular clefts are the site of diffusion for small molecules such as peptides having a molecular weight inferior to 3,000. For the fenestrated capillary bed, we have shown that fenestrae are the site through which plasma constituents cross the capillary wall. However, and in spite of the existence of these large open pores, the endothelial cells still display the tubulo-vesicular system involved in transport of large molecules and their intercellular clefts are also the site of diffusion of small molecules. Making consensus on the existence of an intracellular tubulo-vesicular system in non-fenestrated capillaries, responsible for the transport of large molecules by the endothelial cells, and understanding the rational for the fenestrated capillary to have three paths for transport--the fenestrae, the tubulo-vesicular system, and the inter-endothelial clefts--require further investigation. PMID:12112441

Bendayan, Moise

2002-06-01

347

Use of a high magnetic field to visualize fluids and to study wettability in porous media by MRI  

SciTech Connect

Magnetic Resonance Imaging (MRI) is very useful for core analysis because it gives information related to petrophysical parameters: porosity and fluid saturations. The authors have used a high magnetic field of 9.4 Tesla to study fluid distributions in porous media. The use of high magnetic field coupled with strong gradients (up to 20 G/cm) enable the authors to produce images with a good resolution and to obtain very thin slices. The different applications studied are visualization of oil and water distributions during a flooding experiment, and study of wettability by NMR and MRI. For this last application, the authors have investigated to decouple the influence of pore size distribution and wettability in relaxation parameters.

Chardaire-Riviere, C.; Roussel, J.C. [Institut Francais du Petrole, Rueil-Malmaison (France)

1993-12-31

348

Synthesis of fluorinated nano-silica and its application in wettability alteration near-wellbore region in gas condensate reservoirs  

NASA Astrophysics Data System (ADS)

Fluorinated silica nanoparticles were prepared to alter rock wettability near-wellbore region in gas condensate reservoirs. Hence fluorinated silica nanoparticles with average diameter of about 80 nm were prepared and used to alter limestone core wettability from highly liquid-wet to intermediate gas-wet state. Water and n-decane contact angles for rock were measured before and after treatment. The contact angle measured 147 for water and 61 for n-decane on the core surface. The rock surface could not support the formation of any water or n-decane droplets before treatment. The functionalized fluorinated silica nanoparticles have been confirmed by the Csbnd F bond along with Sisbnd Osbnd Si bond as analyzed by FT-IR. The elemental composition of treated limestone core surface was determined using energy dispersive X-ray spectroscopy analyses. The final evaluation of the fluorinated nanosilica treatment in terms of its effectiveness was measured by core flood experimental tests.

Mousavi, M. A.; Hassanajili, Sh.; Rahimpour, M. R.

2013-05-01

349

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

350

Myocardial capillaries in the fetal and the neonatal rat: a morphometric analysis of the maturing myocardial capillary bed.  

PubMed

Developing myocardial capillaries from 16-day-gestation fetus to adult undergo several morphological changes including a thinning of the lateral extensions of the capillary endothelial cells, the formation of a basal lamina, and an increase in the number of plasmalemmal vesicles. A decrease in the extracellular space, an increase in the number of capillaries, and a decrease in the capillary diameter were also observed during the developmental period. In view of these ultrastructural changes, a morphometric analysis was made on the developing myocardial wall to demonstrate specific quantitative changes. The volumes which were occupied by capillary endothelial cells, capillary lumina, extracellular space, and myocardial myocytes within a reference volume of myocardium were measured; and we found that 8% of the reference myocardial volume was occupied by capillary endothelial cells, 85% was occupied by myocardial myocytes, 4% was occupied by capillary lumina, and, except for a significant change in extracellular space at 16 days gestation, 3% was occupied by extracellular space. Each volume ratio was found to be nearly constant throughout the studied period. In contrast to this constancy in the volume ratios, other parameters which were measured demonstrated significant changes during the developmental period studied. These overall changes include a 135% increase in capillary density, a 63% increase in luminal surface area of capillary endothelial cells, a 24% decrease in capillary diameter, a 12% decrease in diffusion distance, and a 35% decrease in the diameter of the erythrocyte population.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3618523

Porter, G A; Bankston, P W

1987-06-01

351

Influence of nickel-phosphorus surface roughness on wettability and pores formation in solder joints for high power electronic applications  

NASA Astrophysics Data System (ADS)

Electroless nickel-high-phosphorus Ni-P plating is used as substrate coating in the electronic component technology. The ability to minimize pores formation in solder joints and the wettability of the Ni-P layer remain points of investigation. The qualities and the control of the physical and chemical properties of the deposits are essential for the reliability of the products. In this contribution it has been measured how a controlled change of one property of the Ni-P surface, its average roughness, changes the wettability of this surface before soldering completion, at ambient temperature and under ambient air, and how it contribute to change the amount and size of pores inside solder joints, after soldering completion. Before all, observations of the Ni-P surfaces using scanning electron microscopy have been achieved. Then the wettability has been measured through the determination of both the disperse and the polar fractions of the substrate surface tension, based on the measurements of the wetting angle for droplets of four different liquids, under ambient air and at room temperature (classical sessile drop technique). Finally the X-ray micro-radiography measurements of both the area fraction of pores and the size of the largest pore inside the solder joint of dice laser soldered on the studied substrate, using high melting temperature solder (300 C, PbSnAg) have been achieved. This study clearly demonstrates that both the ability to minimize pores formation in solder joints and the wettability under ambient conditions of the Ni-P substrate decrease and become more variable when its average roughness increases. These effects can be explained considering the Cassie-Baxter model for rough surface wetting behaviour, completed by the model of heterogeneous nucleation and growth for gas bubbles inside a liquid.

Vivet, L.; Joudrier, A.-L.; Tan, K.-L.; Morelle, J.-M.; Etcheberry, A.; Chalumeau, L.

2013-12-01

352

Effect of fatty acids, water composition and pH on the wettability alteration of calcite surface  

Microsoft Academic Search

Fatty acids in presence of water film alter calcite surface to oil-wet. The wettability alteration is dependent on the structure of the fatty acids, water composition and pH. Long chain fatty acid (stearic acid), strongly adsorbs onto the calcite surface from oil phase (n-C10) in oil\\/water\\/calcite system as indicated by contact angle measurements. On the other hand, short chain fatty

K. A. Rezaei Gomari; A. A. Hamouda

2006-01-01

353

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

2013-09-25

354

Surface Modification Methods to Control Wettability in Immiscible Fluid Displacement Experimental Model Systems Relevant to Geological Carbon Sequestration  

NASA Astrophysics Data System (ADS)

Wettability is a critical parameter influencing immiscible fluid displacements relevant to geological carbon sequestration. Fully water-wet clean silica surfaces can be modified with silanes to alter the wettability, with the majority of such efforts to date related to conversions of water-wet to oil-wet systems. While a sizable literature exist on contact angles obtained on silanized surfaces, these are by and large air-water contact angle data, not the oil-water contact angles needed. We have investigated a large range of silanes to modify silica surfaces over a range of wettabilities, measuring both air-water and oil-water contact angles. We have identified surface modifications to produce intermediate wet surfaces. We have found a linear correlation between air-water contact angles and oil-water contact angles, enabling literature data on air-water contact angles to be interpreted in terms of likely oil-water contact angles. In addition, we have found that while glass and silica surfaces modified by the same chemistry give the same contact angles in terms of air water contact angles, the surfaces are not as similar in terms of oil-water contact angles. These studies are being carried out in conjunction with immiscible displacements of water by liquid and supercritical CO2 in microfabricated pore network micromodels in silicon with oxidized silica surfaces and glass cover plates.

Grate, J. W.; Warner, M. G.; Oostrom, M.; Zhang, C.; Wietsma, T. W.; Pittman, J. W.; Dehoff, K. J.

2011-12-01

355

Germination of Phyllosticta ampelicidaPycnidiospores: Prerequisite of Adhesion to the Substratum and the Relationship of Substratum Wettability  

PubMed

Pycnidiospores of Phyllosticta 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 (straight thetaa) formed by a water drop of >80, e.g., grape leaf, polystyrene, Teflon, polycarbonate, collodion, and glass treated with the silanes n-octadecyltrichlorosilane, dimethyldichlorosilane, or diphenyldichlorosilane. When pycnidiospores were deposited on more wettable surfaces they did not attach firmly and did not germinate. Such highly wettable surfaces had straight thetaa

Kuo; Hoch

1996-03-01

356

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, especially 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

2013-09-01

357

Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability  

NASA Astrophysics Data System (ADS)

The main aim of the work was to investigate the wettability of different surface materials with vegetable oil (olive oil) over the temperature range of 25-200 C to understand the differences in cleanability of different surfaces exposed to high temperatures in food processes. The different surface materials investigated include stainless steel (reference), PTFE (polytetrafluoroethylene), silicone, quasicrystalline (Al, Fe, Cr) and ceramic coatings: zirconium oxide (ZrO2), zirconium nitride (ZrN) and titanium aluminum nitride (TiAlN). The ceramic coatings were deposited on stainless steel with two different levels of roughness. The cosine of the contact angle of olive oil on different surface materials rises linearly with increasing temperature. Among the materials analyzed, polymers (PTFE, silicone) gave the lowest cos ? values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos ? values increases with increasing roughness and surface flaws. Correlation analysis indicates that the measured contact angle values gave useful information for grouping easy-clean polymer materials from the other materials; for the latter group, there is no direct relation between contact angle and cleanability. In addition to surface wettability with oil many other factors such as roughness and surface defects play an essential role in determining their cleanability.

Ashokkumar, Saranya; Adler-Nissen, Jens; Mller, Per

2012-12-01

358

The role of seeding in the morphology and wettability of ZnO nanorods films on different substrates  

NASA Astrophysics Data System (ADS)

Spray pyrolysis (SP) and spray-gel (SG) techniques were used to deposit ZnO seeds on Fluor doped tin oxide glasses (FTO), heated at 350 C or 130 C, and PET heated at 90 C. The effect of seeding on the morphology and wettability of ZnO nanorods (NRs) films grown by wet chemical methods was analyzed. The morphology and wettability of ZnO NRs films depend on the seeding process. SP seeds formed from zinc acetate dissolved in water ethanol mixtures yield vertically aligned ZnO NRs, whose diameters and dispersion size are determined by the ethanol/water ratio in the precursor solution. SG seeds formed from a methanol ZnO sol produce a ring patterned distribution on the FTO substrate. The drying of ZnO sol drops impinging on the substrate produces high density of seeds along a ring yielding textured films with NRs vertically oriented on the rings and multi-oriented outside them. This effect was not observed when ZnO NRs grown onto the ZnO/PET substrate, however rod diameter is related with the density of seeds. This way to control the density and diameter of NRs deposited onto a substrate modify the wettability and opens new possibilities for the design of tailored nanomaterials for photochemical applications. Both type of NRs films showed a strong luminescence emission in the UV and in the blue, associated with surface and intrinsic defects.

Rodrguez, Juan; Onna, Diego; Snchez, Luis; Marchi, M. Claudia; Candal, Roberto; Ponce, Silvia; Bilmes, Sara A.

2013-08-01

359

Photon-induced tunable and reversible wettability of pulsed laser deposited W-doped ZnO nanorods  

NASA Astrophysics Data System (ADS)

ZnO nanorods arrays were prepared on soda lime glass substrate by pulsed laser deposition method. Hexagonal rod-like ZnO rods were obtained under different conditions. Well-defined ZnO nanorods arrays were selected among different samples having various morphologies and sizes already studied by X-ray diffraction (XRD) and atomic force microscopy (AFM). Here, we report on the contact angle measurement (CAM) of one of these samples. A systematic change of the surface wettability is observed in W-doped ZnO nanostructures. The water contact angle (WCA) of a 1 wt.% of WO3 target content was found to be the transition doping level from hydrophilic surface to a hydrophobic surface. We attributed the transition in surface wettability of the film with the doping to incorporation increase of tungsten into the film. Such characteristic surface wettability can play a key role in the adhesion of various layers on W-ZnO nanorods arrays for optoelectronic device applications.

Ngom, B. D.; Sakho, O.; Ndiaye, S.; Bartali, R.; Diallo, A.; Gaye, M. B.; Bady, S.; Manyala, N.; Maaza, M.; Beye, A. C.

2011-08-01

360

Symmetry Induced 4-Wave Capillary Wave Turbulence  

E-print Network

We report theoretical and experimental results on 4-wave capillary wave turbulence. A system consisting of two inmiscible and incompressible fluids of the same density can be written in a Hamiltonian way for the conjugated pair $(\\eta,\\Psi)$. When given the symmetry $z\\to-z$, the set of weakly non-linear interacting waves display a Kolmogorov-Zakharov (KZ) spectrum $n_k\\sim k^{-4}$ in wave vector space. The wave system was studied experimentally with two inmiscible fluids of almost equal densities (water and silicon oil) where the capillary surface waves are excited by a low frequency random forcing. The power spectral density (PSD) and probability density function (PDF) of the local wave amplitude are studied. Both theoretical and experimental results are in fairly good agreement with each other.

Gustavo Dring; Claudio Falcn

2009-01-22

361

Dynamics of liquid penetration into capillary tubes.  

PubMed

The dynamics of penetration is considered in the case where inertia effects are small. The effect of the contact line speed on the dynamic contact angle is taken into consideration. Analytical solutions are obtained for short and large times, and are found to cover together most of the time domain. The results obtained numerically show good agreement with the asymptotic solutions. The large-time solutions are valid in the case of penetration into horizontal capillaries. The large-time asymptotic solution shows a correction term compared to the Lucas-Washburn equation, which is found to be a limiting case valid for very large times (horizontal capillaries case). The analysis shows how to include gravity effects in the case of penetration into vertical tubes. Excellent agreement is found with available published experimental data. PMID:17692326

Chebbi, R

2007-11-01

362

The geometry and wetting of capillary folding  

E-print Network

Capillary forces are involved in a variety of natural phenomena, ranging from droplet breakup to the physics of clouds. The forces from surface tension can also be exploited in industrial application provided the length scales involved are small enough. Recent experimental investigations showed how to take advantage of capillarity to fold planar structures into three-dimensional configurations by selectively melting polymeric hinges joining otherwise rigid shapes. In this paper we use theoretical calculations to quantify the role of geometry and fluid wetting on the final folded state. Considering folding in two and three dimensions, studying both hydrophilic and hydrophobic situations with possible contact angle hysteresis, and addressing the shapes to be folded to be successively infinite, finite, curved, kinked, elastic, we are able to derive an overview of the geometrical parameter space available for capillary folding.

Jean-Philippe Praud; Eric Lauga

2014-03-18

363

Capillary Electrophoresis Applied to Proteomic Analysis  

PubMed Central

In the postgenomic era, proteomics has become a dominant field for identifying and quantifying the complex protein machinery of the cell. The expression levels, post-translational modifications, and specific interactions of proteins control the biology of such processes as development, differentiation, and signal transduction. Studies of the proteins involved in these processes often leads to a better understanding of biology and of human disease. Powerful separation techniques and sensitive detection methods enable researchers to untangle these complicated networks of processes. Capillary electrophoresis coupled with either mass spectrometry or laser-induced fluorescence are two of the techniques that make this possible. This review will cover proven capillary electrophoresis-based methods for proteomics on the cell and tissue level and their application in biological and clinical studies, relevant new developments in enabling technology such as microfluidic CE-MS demonstrated on model systems, and comment on the future of CE in proteomics. PMID:19360788

Fonslow, Bryan R.; Yates, John R.

2012-01-01

364

Geometric background charge: dislocations on capillary bridges  

E-print Network

Recent experiments have shown that colloidal crystals confined to weakly curved capillary bridges introduce groups of dislocations organized into `pleats' as means to relieve the stress caused by the Gaussian curvature of the surface. We consider the onset of this curvature-screening mechanism, by examining the energetics of isolated dislocations and interstitials on capillary bridges with free boundaries. The boundary provides an essential contribution to the problem, akin to a background charge that "neutralizes" the unbalanced integrated curvature of the surface. This makes it favorable for topologically neutral dislocations and groups of dislocations - rather than topologically charged disclinations and scars - to relieve the stress caused by the unbalanced gaussian curvature of the surface. This effect applies to any crystal on a surface with non-vanishing integrated Gaussian curvature and stress-free boundary conditions. We corroborate the analytic results by numerically computing the energetics of a defected lattice of springs confined to surfaces with weak positive and negative curvature

William Irvine; Vincenzo Vitelli

2012-06-19

365

Capillary electrophoretic separation of biologically active amines and acids using nanoparticle-coated capillaries.  

PubMed

This manuscript describes dynamic coating of capillaries with poly(L-lysine) (PLL) and silica nanoparticles (SiO2 NPs) and use of the as-prepared capillaries for the separation of biogenic amines and acids by CE in conjunction with LIF detection. The directions of EOF are controlled by varying the outmost layer of the capillaries with PLL and SiO2 NPs, respectively. Over the pH range 3.0-5.0, the (PLL-SiO2NP)n-PLL capillaries have an EOF toward the anodic end and are more suitable for the separation of acids with respect to speed, while the (PLL-SiO2NP)n capillaries have an EOF toward the cathodic end and are more suitable for the separation of biogenic amines regarding speed and sensitivity. The separations of standard solutions containing five amines and two acids by CE with LIF detection using (PLL-SiO2NP)2-PLL and (PLL-SiO2NP)3 capillaries were accomplished within 10 and 7 min, providing plate numbers of 3.8 and 5.0x10(4) plates/m for 5-hydroxytryptamine (5-HT), respectively. The LODs for 5-HT and 5-hydroxyindole-3-acetic acid (5-HIAA) are 32 and 2 nM and 0.2 and 1.5 nM when using the (PLL-SiO2NP)2-PLL and (PLL-SiO2NP)3 capillaries, respectively. Identification and quantification of 5-HIAA, homovanillic acid, and DL-vanillomandelic acid in urine samples from a male before and after drinking green tea were tested to validate practicality of the present approach. The results show that the (PLL-SiO2NP)2-PLL capillary provides greater resolving power, while the (PLL-SiO2NP)3 capillary provides better sensitivity, higher efficiency, and longer durability for the separation of the amines and acids. PMID:18383029

Huang, Yu-Fen; Chiang, Cheng-Kang; Lin, Yang-Wei; Liu, Kungtien; Hu, Chou-Chen; Bair, Ming-Jong; Chang, Huan-Tsung

2008-05-01

366

Skeletal muscle capillary function: contemporary observations and novel hypotheses.  

PubMed

The capillary bed constitutes a vast surface that facilitates exchange of O2, substrates and metabolites between blood and organs. In contracting skeletal muscle, capillary blood flow and O2 diffusing capacity, as well as O2 flux, may increase two orders of magnitude above resting values. Chronic diseases, such as heart failure and diabetes, and also sepsis impair these processes, leading to compromised energetic, metabolic and, ultimately, contractile function. Among researchers seeking to understand blood-myocyte exchange in health and the basis for dysfunction in disease, there is a fundamental disconnect between microcirculation specialists and many physiologists and physiologist clinicians. While the former observe capillaries and capillary function directly (muscle intravital microscopy), the latter generally use indirect methodologies (e.g. post-mortem tissue analysis, 1-methyl xanthine, contrast-enhanced ultrasound, permeability-surface area product) and interpret their findings based upon August Krogh's observations made nearly a century ago. 'Kroghian' theory holds that only a small fraction of capillaries support red blood cell (RBC) flux in resting muscle, leaving the vast majority to be 'recruited' (i.e. to initiate RBC flux) during contractions, which would constitute the basis for increasing surface area for capillary exchange and reducing capillary-mitochondrial diffusion distances. Experimental techniques each have their strengths and weaknesses, and often the correct or complete answer to a problem emerges from integration across multiple technologies. Today, Krogh's entrenched 'capillary recruitment' hypothesis is challenged by direct observations of capillaries in contracting muscle, which is something that he and his colleagues could not do. Moreover, in the peer-reviewed scientific literature, application of a range of contemporary physiological technologies, including intravital microscopy of contracting muscle, magnetic resonance, near-infrared spectroscopy and phosphorescence quenching, combined with elegant in situ and in vivo models, suggest that the role of the capillary bed, at least in contracting muscle, is subserved without the necessity for de novo capillary recruitment of previously non-flowing capillaries. When viewed within the context of the capillary recruitment hypothesis, this evidence casts serious doubt on the interpretation of those data that are based upon Kroghian theory and indirect methodologies. Thus, today a wealth of evidence calls for a radical revision of blood-muscle exchange theory to one in which most capillaries support RBC flux at rest and, during contractions, capillary surface area is 'recruited' along the length of previously flowing capillaries. This occurs, in part, by elevating capillary haematocrit and extending the length of the capillary available for blood-myocyte exchange (i.e. longitudinal recruitment). Our understanding of blood-myocyte O2 and substrate/metabolite exchange in health and the mechanistic basis for dysfunction in disease demands no less. PMID:23995101

Poole, David C; Copp, Steven W; Ferguson, Scott K; Musch, Timothy I

2013-12-01

367

Capillary-Effect Root-Environment System  

NASA Technical Reports Server (NTRS)

Capillary-effect root-environment system (CERES) is experimental apparatus for growing plants in nutrient solutions. Solution circulated at slight tension in cavity filled with plastic screen and covered by porous plastic membrane. By adsorptive attraction, root draws solution through membrane. Conceived for use in microgravity of space, also finds terrestrial application in germinating seedlings, because it protects them from extremes of temperature, moisture, and soil pH and from overexposure to fertilizers and herbicides.

Wright, Bruce D.

1991-01-01

368

Packed capillary columns for liquid chromatography  

Microsoft Academic Search

SummaryFused silica capillaries, ? 130 ? 0.32mm have been packed with small reversed phase spherical silica particles, 3 or 2?m,\\u000a in order to achieve LC-systems giving high plate numbers at relatively low pressure drop in short analysis times. At optimal\\u000a conditions, columns packed with 3?m particles showed reduced plate heights, h, around 2.5, and the column flow resistance,\\u000a ?, was

S. Hoffmann; L. Blomberg

1987-01-01

369

Hydrogen peroxide production in capillary underwater discharges  

Microsoft Academic Search

Hydrogen peroxide production by an AC driven capillary underwater discharge was investigated quantitatively. Concentration of formed hydrogen peroxide was measured by a colorimetric method using a specific reaction between H2O2 and a titanium reagent. It comes out that the amount of H2O2 increases linearly during the first hour of the discharge duration and is slightly higher at the high voltage

F. de Baerdemaeker; M. Simek; M. Clupek; P. Lukes; C. Leys

2006-01-01

370

Hydrogen peroxide production in capillary underwater discharges  

Microsoft Academic Search

Hydrogen peroxide production by an AC driven capillary underwater discharge was investigated quantitatively. Concentration\\u000a of formed hydrogen peroxide was measured by a colorimetric method using a specific reaction between H2O2 and a titanium reagent. It comes out that the amount of H2O2 increases linearly during the first hour of the discharge duration and is slightly higher at the high voltage

F. De Baerdemaeker; M. imek; M. ?lupek; P. Luke; C. Leys

2006-01-01

371

Capillary Electrophoresis with Indirect Electrochemiluminescence Detection  

Microsoft Academic Search

An indirect electrochemiluminescence (IECL) detection for capillary electrophoresis (CE) is presented in this article. IECL is based on the inhibition of Ru(bpy)3 \\/TPA system. The developed technique is successfully applied to the analysis of phenolic compounds: phenol, o?chlorophenol, p?nitrophenol, and 2,4,6?trinitrophenol. The factors that influenced the separation and detection were investigated in detail. On the optimized condition, the tested phenols

Jianzhen Kang; Jifeng Liu; Haibo Qiu; Jilin Yan; Xiurong Yang; Erkang Wang

2005-01-01

372

Concentration Polarization in an Ultrafiltering Capillary  

PubMed Central

Concentration polarization, the accumulation of retained solute next to an ultrafiltering membrane, elevates osmotic pressure above that which would exist in the absence of polarization. For ultrafiltration in a cylindrical tube, use of the radially averaged solute concentration results in an underestimate of osmotic pressure, yielding an effective hydraulic permeability (k) less than the actual membrane hydraulic permeability (km). The extent to which k and km might differ in an ultrafiltering capillary has been examined theoretically by solution of the momentum and species transport equations for idealized capillaries with and without erythrocytes. For diameters, flow velocities, protein concentrations and diffusivities, and ultrafiltration pressures representative of the rat glomerular capillary network, results indicate that the effects of polarization are substantial without erythrocytes (k/km = 0.7) and persist, but to a lesser extent, with erythrocytes (k/km = 0.9), the reduction in polarization in the latter case being due to enhanced plasma mixing. In accord with recent experimental findings in rats, k is found to be relatively insensitive to changes in glomerular plasma flow rate. PMID:4836036

Deen, William M.; Robertson, Channing R.; Brenner, Barry M.

1974-01-01

373

Polydopamine as an adhesive coating for open tubular capillary electrochromatography.  

PubMed

Polydopamine (PolyD) coating was used as an adhesive layer in the preparation of biological stationary phases for open tubular capillary electrochromatography (OT-CEC). The influence of coating solution freshness, coating time, temperature and dopamine hydrochloride concentration on the PolyD layer formation was studied. The performance of the polyD coating was monitored by measuring the electro-osmotic flow in coated capillaries. Following polyD coating of the capillary, secondary layer material (e.g. cell membrane solutions, phospholipid mixtures or mitochondria) was inserted into the capillary for at least 1?h. The performance of these double-coated capillaries (a polyD layer+a biological material layer) was compared with capillaries containing the respective biological material directly attached to the capillary wall. The study reveals that the presence of polyD layer in fused silica capillaries improves the performance of lipid and membrane fragment coatings in capillaries. At the same time, the thickness of the polyD layer does not have marked impact on the secondary coatings. Analysis with test analytes demonstrated that double-coated capillaries can be applied to study membrane-drug interactions. PMID:21449069

Martma, Kert; Habicht, Kaia-Liisa; Ramirez, Xochitl M; Tepp, Kersti; Kmbre, Tuuli; Volobujeva, Olga; Shimmo, Ruth

2011-04-01

374

Anisotropic wettability of laser micro-grooved SiC surfaces  

NASA Astrophysics Data System (ADS)

Wettability on silicon carbide (SiC) substrates with laser processing micro-groove-liked structures was introduced to discuss the anisotropic wetting properties. The surface topography and chemical composition, on the polished and textured substrates were measured by energy dispersive X-ray analysis (EDX) and Raman measurement system (RS), respectively. Water contact angles in both parallel and perpendicular direction to grooves were also measured. Results show that chemical composition on the laser processed surface was almost the same with that on the polished surface, except for the content of O increased and the Si decreased. The contact angle in the parallel direction was larger than the perpendicular direction which indicates that the anisotropy was significant on the groove-liked textures. The difference of contact angle value between these two directions ranged from 15.7 to 47.4. While the difference would be less than 24, when both groove spacing and width were larger than 100 ?m. The less the size of groove spacing and width was, the more obvious the anisotropy became. The findings may produce a promising way to reduce water adsorption on the gas seal surfaces.

Ma, Chunhong; Bai, Shaoxian; Peng, Xudong; Meng, Yonggang

2013-11-01

375

Adaptive wettability-enhanced surfaces ordered on molded etched substrates using shrink film  

NASA Astrophysics Data System (ADS)

Superhydrophobic surfaces in nature exhibit desirable properties including self-cleaning, bacterial resistance, and flight efficiency. However, creating such intricate multi-scale features with conventional fabrication approaches is difficult, expensive, and not scalable. By patterning photoresist on pre-stressed shrink-wrap film, which contracts by 95% in surface area when heated, such features over large areas can be obtained easily. Photoresist serves as a dry etch mask to create complex and high-aspect ratio microstructures in the film. Using a double-shrink process, we introduce adaptive wettability-enhanced surfaces ordered on molded etched (AWESOME) substrates. We first create a mask out of the childrens toy Shrinky-Dinks by printing dots using a laserjet printer. Heating this thermoplastic sheet causes the printed dots to shrink to a fraction of their original size. We then lithographically transfer the inverse pattern onto photoresist-coated shrink-wrap polyolefin film. The film is then plasma etched. After shrinking, the film serves as a high-aspect ratio mold for polydimethylsiloxane, creating a superhydrophobic surface with water contact angles >150 and sliding angles <10. We pattern a microarray of sticky spots with a dramatically different sliding angle compared to that of the superhydrophobic region, enabling microtiter-plate type assays without the need for a well plate.

Jayadev, Shreshta; Pegan, Jonathan; Dyer, David; McLane, Jolie; Lim, Jessica; Khine, Michelle

2013-01-01

376

Wettability, interface structure, and chemistry in functionalized poly(chloro-para-xylylene) films  

NASA Astrophysics Data System (ADS)

Genetically hydrophobic polymer interfaces are functionalized by oxygen plasma and systematically analyzed using contact angle measurements, atomic force microscopy, and high resolution X-ray photoelectron spectroscopy. High resolution C 1s core level spectra indicate that approximately three of five hydrogen-abstracted carbon sites at the surface become terminated in equal weight by aldehyde and carboxylic acid. Without altering the global structure of the interface, the plasma treatments at ERF > 100 J generate a network of small protuberances which grows with ERF, and a wavelength selection with a characteristic length scale increasing with ERF. While the polymer surface is continuously eroded in the rate of 4 nm/100 J, a delicate balance between the growth of the network of the local structure and the progression of the wavelength selection allows the polymer interface to maintain a relatively high level of the low molecular weight materials, which is responsible for the enhanced surface concentration of carbonyl group during the abrasive functionalization process above ERF 100 J. The sharp increase in the wettability of the polymer interface upon the plasma treatment is closely related to the surface concentration of the total polar functional group containing oxygen rather than that of a specific functional group.

Bae, Junwan; Lee, I. J.

2014-06-01

377

Synthesis and controllable wettability of micro- and nanostructured titanium phosphate thin films formed on titanium plates.  

PubMed

The hydrothermal treatment of a titanium plate in a mixed aqueous solution of hydrogen peroxide and aqueous phosphoric acid under different conditions results in the formation of various titanium phosphate thin films. The films have various crystal structures such as Ti2O3(H2PO4)22H2O, ?-titanium phosphate (Ti(HPO4)2H2O), ?-titanium phosphate (Ti2O(PO4)2H2O), or low-crystallinity titanium phosphate and different morphologies that have not been previously reported such as nanobelts, microflowers, nanosheets, nanorods, or nanoplates. The present study also suggests the mechanisms behind the formation of these thin films. The crystal structure and morphology of the titanium phosphate thin films depend strongly on the concentration of the aqueous hydrogen peroxide solution, the amount of phosphoric acid, and the reaction temperature. In particular, hydrogen peroxide plays an important role in the formation of the titanium phosphate thin films. Moreover, controllable wettability of the titanium phosphate thin films, including superhydrophilicity and superhydrophobicity, is reported. Superhydrophobic surfaces with controllable adhesion to water droplets are obtained on ?-titanium phosphate nanorod thin films modified with alkylamine molecules. The adhesion force between a water droplet and the thin film depends on the alkyl chain length of the alkylamine and the duration of ultraviolet irradiation utilized for photocatalytic degradation. PMID:24712291

Yada, Mitsunori; Inoue, Yuko; Sakamoto, Ayako; Torikai, Toshio; Watari, Takanori

2014-05-28

378

Wettability and kinetics of hydroxyapatite precipitation on a laser-textured Ca-P bioceramic coating.  

PubMed

Surface-textured calcium phosphate coatings at four different length scales were synthesized on titanium-based alloys using a pulsed Nd:YAG laser system by a direct melting technique. The textures were obtained by varying the laser spot overlap with a change in laser traverse speed. Surface roughness measurements of the textured coatings carried out using a white light interferometer indicated a decrease in roughness with increasing laser scan speed. Wettability of the coated samples measured using a static sessile drop technique demonstrated an increased hydrophilicity with increasing laser scan speed. The influence of such textures and the associated surface roughness on the precipitation kinetics of hydroxyapatite (HA) during immersion in simulated body fluid (SBF) was the prime focus of the present paper. The mineralized samples obtained after immersion in SBF were characterized using X-ray diffraction, energy-dispersive spectroscopy and scanning electron microscopy to understand the kinetics of HA precipitation. The results thereafter confirmed that the precipitation kinetics of HA was strongly modulated by the varying surface roughness. PMID:19362524

Paital, Sameer R; Dahotre, Narendra B

2009-09-01

379

Effect of annealing temperature on wettability of TiO2 nanotube array films  

PubMed Central

Highly ordered TiO2 nanotube array (TN) films were prepared by anodization of titanium foil in a mixed electrolyte solution of glycerin and NH4F and then annealed at 200C, 400C, 600C, and 800C, respectively. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), water contact angle (WCA), and photoluminescence (PL). It was found that low temperature (below 600C) has no significant influence on surface morphology, but the diameter of the nanotube increases from 40 to 50nm with increasing temperature. At 800C, the nanotube arrays are completely destroyed and only dense rutile film is observed. Samples unannealed and annealed at 200C are amorphous. At 400C, anatase phase appears. At 600C, rutile phase appears. At 800C, anatase phase changes into rutile phase completely. The wettability of the TN films shows that the WCAs for all samples freshly annealed at different temperatures are about 0. After the annealed samples have been stored in air for 1month, the WCAs increase to 130, 133, 135, 141, and 77, respectively. Upon ultraviolet (UV) irradiation, they exhibit a significant transition from hydrophobicity to hydrophilicity. Especially, samples unannealed and annealed at 400C show high photoinduced hydrophilicity.

2014-01-01

380

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

SciTech Connect

We report on a preliminary study of wetting effects of synthetic oil-based mud components on the wetting of mica surfaces using drilling mud fractions obtained from two wells drilled with synthetic oil-based muds (SBM). We have used these SBM fractions, one a filtrate and the other a centrifugate, to develop testing protocols for studies on smooth mica surfaces. Both SBM fractions changed the wetting of clean, dry mica surfaces, making them preferentially oil-wet. Solvents were tested to clean the mica with varying degrees of success. In tests designed to simulate contact between SBM fractions and reservoir pore surface, changes of wetting of mica that had previously been exposed to brine and crude oil were examined using six different crude oils in combination with several different brine formulations. Four of the six oils produced preferentially water-wet surfaces whereas two produced fairly oil-wet conditions on mica. Exposure to the SBM fractions tended to increase decane/water advancing contact angles on the more water-wet surfaces and to decrease those on the more oil-wet surfaces. Cleaning solvents were compared for their efficacy and the possibility of wettability restoration was examined for some of the cleaned surfaces.

Jill S. Buckley; Norman R. Morrow

2002-12-01

381

Tunable surface wettability and water adhesion of Sb2S3 micro-/nanorod films  

NASA Astrophysics Data System (ADS)

Antimony sulfide (Sb2S3) films were successfully prepared by spin coating Sb2S3 micro-/nanorods with different sizes on glass slides, which was synthesized via a facile and rapid microwave irradiation method. The prepared Sb2S3 micro-/nanorods and films were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle (CA). The as-prepared Sb2S3 films exhibited different surface wettabilities ranging from superhydrophilicity to superhydrophobicity, which was strongly dependent on the diameter of Sb2S3 micro-/nanorod. Sb2S3 film made by nanorods possessed superhydrophobic surface and high water adhesive property. After surface modification with stearic acid, the superhydrophobic surface exhibited an excellent self-cleaning property owing to its low adhesive force. The clarification of three possible states including Wenzel's state, "Gecko" state and Cassie's state for Sb2S3 film surfaces was also proposed to provide a better understanding of interesting surface phenomena on Sb2S3 films.

Zhong, Xin; Zhao, Huiping; Yang, Hao; Liu, Yunling; Yan, Guoping; Chen, Rong

2014-01-01

382

How thermal curing of an organic paper coating changes topography, chemistry, and wettability.  

PubMed

Celluloses are preferred renewable substrates, but hydrophilicity and porosity disfavor their water resistance. We present here an ecofriendly application of imidized nanoparticles and a method to flexibly tune the surface wettability of papers. The soft nanostructured coating is sensitive to thermal curing, which affects both the surface chemistry and morphology. The thermal stability of the coating is first investigated with conventional and modulated differential scanning calorimetry, revealing influences of the imide content and an endotherm reaction below the glass transition temperature at 120-150 C. The latter is studied in detail for an appropriate selection of the copolymer precursors. According to diffuse reflection infrared spectroscopy, Raman spectroscopy, and UV/vis spectroscopy, the endotherm corresponds to an imidization reaction. The morphology of the coatings is followed at various scale levels by contactless roughness measurements and atomic force microscopy. Finally, the experimental values are fitted to the parameters of the Wenzel wetting model, and so-called calibration curves for the relation between contact angles, surface roughness, and surface chemistry are presented. They allow the prediction of the water contact angle of coated papers from the hydrophilic to the hydrophobic range, with a maximum in hydrophobicity after increasing the imide content at 120-150 C curing. PMID:21650187

Samyn, Pieter; Schoukens, Gustaaf; Vonck, Leo; Stanssens, Dirk; Van den Abbeele, Henk

2011-07-01

383

Patterned surface with controllable wettability for inkjet printing of flexible printed electronics.  

PubMed

Appropriate control of substrate surface properties prior to inkjet printing could be employed to improve the printing quality of fine resolution structures. In this paper, novel methods to fabricate patterned surfaces with a combination of hydrophilic and hydrophobic properties are investigated. The results of inkjet printing of PEDOT/PSS conductive ink on these modified surfaces are presented. Selective wetting was achieved via a two-step hydrophilic-hydrophobic coating of 3-aminopropyl trimethoxysilane (APTMS) and 3M electronic grade chemical respectively on PET surfaces; this was followed by a selective hydrophilic treatment (either atmospheric O2/Ar plasma or UV/ozone surface treatment) with the aid of a Nickel stencil. Hydrophobic regions with water contact angle (WCA) of 105 and superhydrophilic regions with WCA <5 can be achieved on a single surface. During inkjet printing of the treated surfaces, PEDOT/PSS ink spread spontaneously along the hydrophilic areas while avoiding the hydrophobic regions. Fine features smaller than the inkjet droplet size (approximately 55 ?m in diameter) can be successfully printed on the patterned surface with high wettability contrast. PMID:24571607

Nguyen, Phuong Q M; Yeo, Lip-Pin; Lok, Boon-Keng; Lam, Yee-Cheong

2014-03-26

384

The effect of iron and copper impurities on the wettability of sphalerite (110) surface.  

PubMed

The effect of impurities in the zinc sulfide mineral sphalerite on surface wettability has been investigated theoretically to shed light on previously reported conflicting results on sphalerite flotation. The effect of iron and copper impurities on the sphalerite (110) surface energy and on the water adsorption energy was calculated with the semi-empirical method modified symmetrically orthogonalized intermediate neglect of differential overlap (MSINDO) using the cyclic cluster model. The effect of impurities or dopants on surface energies is small but significant. The surface energy increases with increasing surface iron concentration while the opposite effect is reported for increasing copper concentration. The effect on adsorption energies is much more pronounced with water clearly preferring to adsorb on an iron site followed by a zinc site, and copper site least favorable. The theoretical results indicate that a sphalerite (110) surface containing iron is more hydrophilic than the undoped zinc sulfide surface. In agreement with the literature, the surface containing copper (either naturally or by activation) is more hydrophobic than the undoped surface. PMID:21462368

Simpson, Darren J; Bredow, Thomas; Chandra, Anand P; Cavallaro, Giuseppe P; Gerson, Andrea R

2011-07-15

385

In situ synthesis of CuO and Cu nanostructures with promising electrochemical and wettability properties.  

PubMed

A strategy is presented for the in situ synthesis of single crystalline CuO nanorods and 3D CuO nanostructures, ultra-long Cu nanowires and Cu nanoparticles at relatively low temperature onto various substrates (Si, SiO2 , ITO, FTO, porous nickel, carbon cotton, etc.) by one-step thermal heating of copper foam in static air and inert gas, respectively. The density, particle sizes and morphologies of the synthesized nanostructures can be effectively controlled by simply tailoring the experimental parameters. A compressive stress based and subsequent structural rearrangements mechanism is proposed to explain the formation of the nanostructures. The as-prepared CuO nanostructures demonstrate promising electrochemical properties as the anode materials in lithium-ion batteries and also reversible wettability. Moreover, this strategy can be used to conveniently integrate these nanostructures with other nanostructures (ZnO nanorods, Co3 O4 nanowires and nanowalls, TiO2 nanotubes, and Si nanowires) to achieve various hybrid hierarchical (CuO-ZnO, CuO-Co3 O4 , CuO-TiO2 , CuO-Si) nanocomposites with promising properties. This strategy has the potential to provide the nano society with a general way to achieve a variety of nanostructures. PMID:24174010

Zhang, Qiaobao; Xu, Daguo; Zhou, Xiang; Wu, Xianwen; Zhang, Kaili

2014-03-12

386

Action Mazes.  

ERIC Educational Resources Information Center

An action maze is a series of reading cards, the first of which outlines a problem situation and offers readers a number of possible courses of action. By working in groups through the cards, communicative skills are developed. The cards can also be used as a writing exercise. (PJM)

Rinvolucri, M. F. G.

1980-01-01

387

Nonlinear gravity-capillary water waves  

NASA Astrophysics Data System (ADS)

Two-dimensional gravity-capillary water waves are analyzed using a fully-nonlinear Cauchy-integral method with spectral accuracy. Standing waves are generated in experiments by vertical oscillation and measured by a non-intrusive optical system along with a wave probe. Nonlinear resonance of standing waves with non-wetting contact line effects are discussed in detail. Amplitude- dependent wave frequency and damping in a glass rectangular tank suggest a new contact-line model. A new type of sideband resonance due to modulated forcing is discovered and explained by weakly-nonlinear analysis. This analytical solution is verified by our numerical simulations and physical experiments. New standing waveforms with dimpled or sharp crests are observed in experiments and computations. These new waveforms have strong symmetry breaking in time as a result of nonlinear harmonic interaction. With increasing wave steepness, steep standing waves experience period- tripling with three distinct forms: sharp crest, dimpled or flat crest, and round crest. Significant breaking occurs in the sharp-crest mode and the dimpled-crest mode. Using a complex-demodulation technique, I find that these breaking waves are related to the same 1:2 internal resonance (harmonic interaction) that causes the new steep waveforms. Novel approaches are used to estimate the (breaking and non-breaking) wave dissipation in steep and breaking standing waves. The breaking events (spray, air entrainment, and plunging) approximately double the wave dissipation. Weak capillarity significantly affects the limiting wave height and the form of standing waves, as demonstrated by both computations and small-scale Faraday-wave experiments. Capillary ripple generation on traveling waves is shown to be significant even at moderate wave steepness. The ubiquitous horizontal asymmetry of traveling waves is shown to be critical to capillary ripple generation. Two new asymmetric modes are identified and are shown to have an important effect on the unsteady generation and modulation of capillary ripples. For standing waves at critical capillary numbers, new waveform with multiple dimples is found at finite amplitude with complex dynamical behavior. These discoveries are shown to bear important implications to remote sensing of the ocean surfaces.

Jiang, Lei

1997-11-01

388

Trajectory of isoelectric focusing from gels to capillaries to immobilized gradients in capillaries  

PubMed Central

This review presents the need for replacing gels in 2D separations for proteomics, where speed, high-throughput, and the ability to characterize trace level proteins or small samples are the current desires. The theme of the review is isoelectric focusing, which is a valuable tool because it pre-concentrates proteins in addition to separating with high peak capacity. The review traces the technological progress from gel IEF to cIEF to packed capillaries with immobilized gradients for cIEF. Multiple capillary techniques are progressing toward meeting the current desires, providing extremely high sensitivity with regard to concentration and to small samples, integrated automation, and high peak capacity from multiple dimensions of separation. Capillaries with immobilized pH gradients for cIEF are emerging, which will alleviate interference from ampholytes and improve reproducibility in separation times when this valuable technique can be used as one of the dimensions. PMID:22930445

Koshel, Brooke M.; Wirth, Mary J.

2013-01-01

389

Capillary climb dynamics in the limits of prevailing capillary and gravity force  

NASA Astrophysics Data System (ADS)

The dynamics of capillary climb of a wetting liquid into a porous medium that is opposed by gravity force is studied numerically. We use the capillary network model, in which an actual porous medium is represented as a network of pores and throats, each following a predefined size distribution function. The liquid potential in the pores along the liquid interface within the network is calculated as a result of capillary and gravity forces. The solution is general, and accounts for changes in the climbing height and climbing velocity. The numerical results for the capillary climb reveal that there are at least two distinct flow mechanisms. Initially, the flow is characterized by high climbing velocity, in which the capillary force is higher than the gravity force, and the flow is the viscous force dominated. For this single-phase flow, the Washburn equation can be used to predict the changes of climbing height over time. Later, for longer times and larger climbing height, the capillary and gravity forces become comparable, and one observes a slower increase in the climbing height as a function of time. Due to the two forces being comparable, the gas-liquid sharp interface transforms into flow front, where the multiphase flow develops. The numerical results from this study, expressed as the climbing height as a power law function of time, indicate that the two powers, which correspond to the two distinct mechanisms, differ significantly. The comparison of the powers with experimental data indicates good agreement. Furthermore, the power value from the Washburn solution is also analyzed, where it should be equal to (1)/(2) for purely viscous force driven flow. This is in contrast to the power value of 0.43 that is found experimentally. We show from the numerical solution that this discrepancy is due to the momentum dissipation on the liquid interface.

Bijeljic, B.; Markicevic, B.; Navaz, H. K.

2011-05-01

390

Capillary climb dynamics in the limits of prevailing capillary and gravity force.  

PubMed

The dynamics of capillary climb of a wetting liquid into a porous medium that is opposed by gravity force is studied numerically. We use the capillary network model, in which an actual porous medium is represented as a network of pores and throats, each following a predefined size distribution function. The liquid potential in the pores along the liquid interface within the network is calculated as a result of capillary and gravity forces. The solution is general, and accounts for changes in the climbing height and climbing velocity. The numerical results for the capillary climb reveal that there are at least two distinct flow mechanisms. Initially, the flow is characterized by high climbing velocity, in which the capillary force is higher than the gravity force, and the flow is the viscous force dominated. For this single-phase flow, the Washburn equation can be used to predict the changes of climbing height over time. Later, for longer times and larger climbing height, the capillary and gravity forces become comparable, and one observes a slower increase in the climbing height as a function of time. Due to the two forces being comparable, the gas-liquid sharp interface transforms into flow front, where the multiphase flow develops. The numerical results from this study, expressed as the climbing height as a power law function of time, indicate that the two powers, which correspond to the two distinct mechanisms, differ significantly. The comparison of the powers with experimental data indicates good agreement. Furthermore, the power value from the Washburn solution is also analyzed, where it should be equal to 1/2 for purely viscous force driven flow. This is in contrast to the power value of ?0.43 that is found experimentally. We show from the numerical solution that this discrepancy is due to the momentum dissipation on the liquid interface. PMID:21728650

Bijeljic, B; Markicevic, B; Navaz, H K

2011-05-01

391

Reversal of renal cortical actions of angiotensin II by verapamil and manganese  

Microsoft Academic Search

Reversal of renal cortical actions of angiotensin II by verapamil and manganese. Experiments were performed on 19 euvolemic Munich Wistar rats to examine the role of calcium in the action of angiotensin II (AII) on the glomerular microcirculation. Intravenous infusion of a mildly pressor dose of AII (N = 7 rats) led to a significant rise in mean glomerular capillary

Iekuni Ichikawa; Joseph F Miele; Barry M Brenner

1979-01-01

392

NRL Capillary Optical Guiding Experiments for Laser Plasma Accelerators  

Microsoft Academic Search

Extended propagation of TW laser pulses has been shown in plasma channels formed with a capillary discharge.( D. Kaganovich, et al., Phys. Rev. E 59) R4769 (1999). Capillary optical guiding experiments at NRL include plasma channels formed using both laser preionization and electrical discharge. Present experiments aim to characterize plasma channel conditions within the capillary. Time-resolved backward-scattered Raman spectra, measured

T. G. Jones; A. Ting; C. I. Moore; R. Hubbard; P. Sprangle; K. Krushelnick; A. Goltsov; A. Morozov; D. Kaganovich; A. Ziegler

1999-01-01

393

Nicked-sleeve interface for two-dimensional capillary electrophoresis  

PubMed Central

We report an improved interface for two-dimensional capillary electrophoresis. This interface is based on capillary tubing and a Plexiglas chip, both of which were milled using a micro-dicing saw. The interface was evaluated and compared to a traditional interface design for both pseudo one-dimensional and two-dimensional capillary electrophoresis. We observe less than 70% transfer efficiency for the traditional design and greater than 90% transfer efficiency with this new interface. PMID:23702824

Flaherty, Ryan J.; Huge, Bonnie J.; Bruce, Spencer M.; Dada, Oluwatosin O.; Dovichi, Norman J.

2013-01-01

394

Numerical Simulation of Blood Flow Through Microvascular Capillary Networks  

Microsoft Academic Search

A numerical method is implemented for computing blood flow through a branching microvascular capillary network. The simulations\\u000a follow the motion of individual red blood cells as they enter the network from an arterial entrance point with a specified\\u000a tube hematocrit, while simultaneously updating the nodal capillary pressures. Poiseuilles law is used to describe flow in\\u000a the capillary segments with an

C. Pozrikidis

2009-01-01

395

Long-Term Culture of Capillary Endothelial Cells  

Microsoft Academic Search

Capillary endothelial cells from rats, calves, and humans, have been carried in long-term culture. Bovine capillary endothelial cells have been cloned and maintained by serial passage for longer than 8 months. This prolonged culture was accomplished by using tumor-conditioned medium, gelatin-coated plates, and a method of enriching cells in primary culture. Cultured bovine capillary endothelial cells produce Factor VIII antigen

Judah Folkman; Christian C. Haudenschild; Bruce R. Zetter

1979-01-01

396

Visualization of capillaries in skeletal muscle by the ATPase reaction.  

PubMed

A simple and reliable technique for the visualization of capillaries in skeletal muscel of dogs, guinea pigs and rats is decribed. 10--20 micrometer frozen sections were incubated in a medium containing Ca2+ and ATP following acid preincubation (pH 3.8--4.2). The capillaries stained in black and were readily seen surrounding the muscle fibers. Serial sections were also treated for alkaline phosphatase. Values for capillary density using both methods were not different. PMID:142963

Sillau, A H; Banchero, N

1977-07-19

397

The study of polyoxometalates formation using capillary zone electrophoresis.  

PubMed

The formation process of polyoxometalates [PMo12 O40 ](3-) and [PMo12 - x Vx O40 ](-3-x) has been studied in aqueous solutions of 0.1 M malonate buffer at pH 2.8-3.0 using CZE. Two different approaches, pre-capillary and in-capillary, were examined and compared. In precapillary mode, the reaction mixture of the reactants and reaction products was injected into the capillary followed by the separation procedure. In in-capillary mode, the sequential input of the reagents and running electrolyte into the capillary and the species separation occurs simultaneously. The optimal parameters of in-capillary separation were established as functions of applied voltage and the length of the intermediate buffer zone between the reagents in the capillary. As a result the best-compromise conditions for the separation of the mixtures containing the reactants, intermediates, and reaction products, in order to achieve the best efficiency, symmetry, and peak areas, were achieved at -18 kV and the input parameter of 900 mbars. It was also shown that in-capillary mode is more informative than pre-capillary mode for studying the complex compound formation process. PMID:24981023

Zdanov, Artem A; Shuvaeva, Olga V

2014-09-01

398

Capillary-Condenser-Pumped Heat-Transfer Loop  

NASA Technical Reports Server (NTRS)

Heat being transferred supplies operating power. Capillary-condenser-pumped heat-transfer loop similar to heat pipe and to capillary-evaporator-pumped heat-transfer loop in that heat-transfer fluid pumped by evaporation and condensation of fluid at heat source and sink, respectively. Capillary condenser pump combined with capillary evaporator pump to form heat exchanger circulating heat-transfer fluids in both loops. Transport of heat more nearly isothermal. Thermal stress in loop reduced, and less external surface area needed in condenser section for rejection of heat to heat sink.

Silverstein, Calvin C.

1989-01-01

399

Distribution of capillaries and diffusion distances in guinea pig myocardium.  

PubMed

A frequency distribution of distances from random points to the nearest capillary was generated from high-magnification photomicrographs of thin sections of the myocardium of seven guinea pigs. Individual mean capillary densities taken from regions viewed in transverse section ranged from approximately 1800 to 2500 capillaries/mm2. Mean (R) and maximal (R95) diffusion distances measured by the closest individual method ranged from R = 6.6 to 8.7 microns and R95 = 11 to 18 microns. Further mathematical analysis of the frequency distributions of diffusion distances indicated that the capillaries of the myocardium are distributed in an ordered array. PMID:6844140

Kayar, S R; Banchero, N

1983-03-01

400

The Effect of Acid Additives on Carbonate Rock Wettability and Spent Acid Recovery in Low Permeability Gas Carbonates.  

E-print Network

??Spent acid retention in the near-wellbore region causes reduction of relative permeability to gas and eventually curtailed gas production. In low-permeability gas carbonate reservoirs, capillary (more)

Saneifar, Mehrnoosh

2012-01-01

401

Enzyme Action  

NSDL National Science Digital Library

In this activity that can be used as a lab or demonstration, learners use Lactaid® and lactose to demonstrate the concept of enzyme action. Learners test a drop of milk and Lactaid® for the presence of glucose using glucose test paper. Learners also discover the color range of glucose test paper readings. In addition, learners construct paper models to help visualize enzyme action.

Crumlish, Jane

2009-01-01

402

Fully packed capillary electrochromatographic microchip with self-assembly colloidal silica beads.  

PubMed

A fully packed capillary electrochromatographic (CEC) microchip showing improved solution and chip handling was developed. Microchannels for the CEC microchip were patterned on a cyclic olefin copolymer substrate by injection molding and packed fully with 0.8-microm monodisperse colloidal silica beads utilizing a self-assembly packing technique. The silica packed chip substrate was covered and thermally press-bonded. After fabrication, the chip was filled with buffer solution by self-priming capillary action. The self-assembly packing at each channel served as a built-in nanofilter allowing quick loading of samples and running buffer solution without filtration. Because of a large surface area-to-volume ratio of the silica packing, reproducible control of electroosmotic flow was possible without leveling of the solutions in the reservoirs resulting 1.3% rsd in migration rate. The capillary electrophoretic separation characteristics of the chip were studied using fluorescein isothiocyanate (FITC)-derivatized amino acids as probe molecules. A mixture of FITC and four FITC-derivatized amino acids was successfully separated with 2-mm separation channel length. PMID:17358045

Park, Jongman; Lee, Dami; Kim, Won; Horiike, Shigeyoshi; Nishimoto, Takahiro; Lee, Se Hwan; Ahn, Chong H

2007-04-15

403

Influence of surface wettability on transport mechanisms governing water droplet evaporation.  

PubMed

Prediction and manipulation of the evaporation of small droplets is a fundamental problem with importance in a variety of microfluidic, microfabrication, and biomedical applications. A vapor-diffusion-based model has been widely employed to predict the interfacial evaporation rate; however, its scope of applicability is limited due to incorporation of a number of simplifying assumptions of the physical behavior. Two key transport mechanisms besides vapor diffusion-evaporative cooling and natural convection in the surrounding gas-are investigated here as a function of the substrate wettability using an augmented droplet evaporation model. Three regimes are distinguished by the instantaneous contact angle (CA). In Regime I (CA ? 60), the flat droplet shape results in a small thermal resistance between the liquid-vapor interface and substrate, which mitigates the effect of evaporative cooling; upward gas-phase natural convection enhances evaporation. In Regime II (60 ? CA ? 90), evaporative cooling at the interface suppresses evaporation with increasing contact angle and counterbalances the gas-phase convection enhancement. Because effects of the evaporative cooling and gas-phase convection mechanisms largely neutralize each other, the vapor-diffusion-based model can predict the overall evaporation rates in this regime. In Regime III (CA ? 90), evaporative cooling suppresses the evaporation rate significantly and reverses entirely the direction of natural convection induced by vapor concentration gradients in the gas phase. Delineation of these counteracting mechanisms reconciles previous debate (founded on single-surface experiments or models that consider only a subset of the governing transport mechanisms) regarding the applicability of the classic vapor-diffusion model. The vapor diffusion-based model cannot predict the local evaporation flux along the interface for high contact angle (CA ? 90) when evaporative cooling is strong and the temperature gradient along the interface determines the peak local evaporation flux. PMID:25105726

Pan, Zhenhai; Weibel, Justin A; Garimella, Suresh V

2014-08-19

404

Control of surface wettability and photomicropatterning with a polymorphic diarylethene crystal upon photoirradiation.  

PubMed

A photochromic diarylethene crystal of 1,2-bis(2-methyl-6-nitro-1-benzothiophen-3-yl)perfluorocyclopentene (1?a) was found to undergo a thermodynamic phase transition at 180?C to form a needle-like crystal, designated as 1?a-?. The phase transition involves melting of the initial ?-crystal and growth of the ?-crystal. The phase transition temperature decreased with the presence of the closed-ring isomer (1?b) in the crystal because of the decrease in the melting temperature. Upon irradiation with ultraviolet (UV) light, compound 1?a in the ?-crystal was converted into 1?b to an extent of 20?%. Consequently, the ?-crystal containing 20?% of 1?b underwent the phase transition accompanied by melting of the crystal and growth of the ?-crystal even at 170?C. Photomicropatterning by the phase transition upon irradiation with UV light using a photomask, followed by heating at 170?C, was successfully accomplished with a resolution in the microcrystalline pattern of about 20??m. The contact angle with water on the ?-microcrystalline phase on a glass substrate was larger than that on the ?-microcrystalline phase by 20. This can be ascribed to a difference in the roughness of the surface. Furthermore, the ?-microcrystal was also found to be formed upon heating an amorphous film of 1?a in poly(methyl methacrylate) for 2?min at 130?C. The crystallized area exhibited a higher water contact angle than the amorphous area. Upon irradiation of the amorphous film with UV light, such crystallization did not take place because of the impurity effect of 1?b in 1?a. Photomicropatterning by the crystallization in the polymer showed a pattern with a higher resolution of about 4??m, which was much better than that of the neat crystal. This photopatterning process represents a useful tool for controlling the surface wettability in relevant applications. PMID:21748813

Kitagawa, Daichi; Yamashita, Itsuka; Kobatake, Seiya

2011-08-22

405

Electrical stability, emulsion stability, and wettability of invert oil-based muds  

SciTech Connect

Until now, drilling-fluid specialists measured trends in the electrical stability (ES) test to decide the appropriate emulsifier treatment for invert-emulsion oil-based muds without knowing what the ES test was measuring. This paper describes what happens in a mud during an ES test, how mud composition affects trends in the ES measurements, and how observed trends can be used to deduce mud-emulsion stability and oil wettability. During an ES test, electrical breakdown is induced in the mud between the electrodes. This process was observed, with an optical microscope, to involve formation of a conductive bridge composed of aqueous fluid and particulate matter. Experiments showed that water forms the conductive pathway in the bridge, whereas the solids appear to be involved only as carriers of the water. E[sub o], the voltage at which the conductive bridge is formed and the current rises abruptly, was found to be a function of the viscosity and the types and concentrations of solids, aqueous fluid, and emulsifiers (surfactants). These trends are consistent with a theoretical expression for breakdown of particulate-contaminated dielectric fluids, which suggests that the E[sub o] of a mud is an absolute measure of its emulsion stability but only a relative measure of its oil-wetting tendency. Trends in E[sub o] are also consistent in most cases with other field indicators of emulsion stability, such as high-temperature, high-pressure (HTHP) fluid loss. Anomalies in E[sub o] trends are explained in terms of a physicochemical model for electrical breakdown.

Growcock, F.B.; Ellis, C.F.; Schmidt, D.D.

1994-03-01

406

Characterization of fluid micro-structures in porous media and their relation to wettability  

NASA Astrophysics Data System (ADS)

Uncertainties in the quantification of transport properties associated with porous soil systems often make the prediction of fluid residence and migration a difficult task. Movement and trapping of immiscible fluids in permeable formations respond to a complex combination of fluid properties, rock properties, the interactions between these fluids and the solid surface, and boundary conditions. This work includes implementation of a sophisticated experimental approach using x-rays and visualization techniques to map the distribution of immiscible liquid structures inside porous samples at the end of various displacement scenarios. We investigate the effect of flowing conditions and wettability on the evolution of fluid micro-structures and trapping in porous media using x-ray microtomography. Core-flooding experiments were conducted to monitor fluid distribution in artificial permeable samples made of solid spherical glass and polyethylene beads (0.43-0.60mm in diameter), which represent a hydrophilic and hydrophobic media, respectively. We present detailed characterizations of the trapped non-wetting phase clusters for the entire body of the cores allowing a more rigorous analysis of the responsible displacement mechanisms. Fluid injection rates and wetting characteristics were found to affect the mobilization and trapping of fluid phases in these porous systems. The degree of sensitivity to various flowing conditions and rock-fluid interactions is of crucial importance to understand immiscible transport mechanisms in natural soil environments. Results from this work are expected to provide a powerful calibration mechanism for physically-based multiphase flow models, which will in turn help in the generalization and extrapolation of experimental observations. Three-dimensional visualization of an oil cluster trapped in the pore space of a granular glass bead pack saturated with brine.

Karpyn, Z. T.; Piri, M.; Singh, G.; Landry, C. J.

2009-12-01

407

Meniscus motion in a prewetted capillary  

NASA Astrophysics Data System (ADS)

A conventional description of the effect of meniscus friction is based on the concept of the dynamic contact angle ?, which depends on the meniscus velocity V according to the Tanner law, ??V1/3. However, recent high-resolution experiments on spontaneous uptake of wetting fluids by capillaries have questioned the universality of the Tanner law. We analyze a mechanism underlying the phenomenological concept of meniscus friction, which finds experimental confirmation. As a case study system, we consider a forced flow of meniscus in a cylindrical capillary. It is assumed that the capillary is prewetted and the coating uniform film could coexist with the static meniscus. Numerical analysis is restricted to van der Waals fluids for which the disjoining pressure ? as a function of film thickness h has the form ??h-3. For these fluids, the equilibrium apparent contact angle is zero. Within the lubrication approximation of the film flow, we show that the nonzeroth dynamic contact angle first appears when the fluid velocity exceeds a certain characteristic value. For smaller velocities, there is no appreciable distortion of the meniscus shape, compared to the equilibrium static configuration. The deformations of the film profile are concentrated at the transition zone between the macroscopic meniscus and the submicron precursor. While the concept of dynamic contact angle seems to be inappropriate for slow flows, the concept of contact line friction serves as a practical alternative to it. We show that when the velocity is slow and there is no visible contact angle, the friction is Newtonian, i.e., the relation between the pressure drop ?P and the meniscus velocity is linear. As the velocity increases, the linear relation transforms into a nonlinear asymptotic law ?P?(V ln V)2/3.

Egorov, Andrei G.; Kornev, Konstantin G.; Neimark, Alexander V.

2003-10-01

408

Capillary zone electrophoresis of proteins with poly(2-hydroxyethyl methacrylate)-coated capillaries: fundamental and applications.  

PubMed

Fused silica capillaries have been modified by atom-transfer radical polymerization (ATRP) to generate covalently bonded polymer films of 2-hydroxyethyl methacrylate. Because the kinetics of ATRP have mainly been investigated in bulk solutions, a GC experiment was set up to examine monomer conversion inside narrow-bore capillaries. It was shown that after 1 to 4 h the reaction was nearly complete. The coating process was further optimized by monitoring EOF, because low EOF indicates high surface coverage. To deal with the very low EOF values, a new approach was used to dramatically reduce the measurement time by overlaying hydrodynamic flow on the electroosmotic flow. The corresponding equations are derived separately in detail. Capillaries were then coated under optimum conditions with linear or cross-linked polymer films. The EOF was reduced over a wide range of pH values. A long-term reproducibility test with both types of functionalization showed that the efficiency of the linear polymer coating decreased significantly over time. With cross-linked films, however, the efficiency even increased. Relative standard deviations for protein migration times were also much lower in cross-linked coated capillaries. Highly efficient separations could be performed for basic and acidic proteins in acidic media, and for the latter even in basic media. PMID:11508469

Leinweber, F C; Stein, J; Otto, M

2001-07-01

409

Noncooled Capillary Inlet: A Source of Systematic Errors in Capillary-Electrophoresis-Based Affinity  

E-print Network

methods. To control the electrolyte temperature, the heat generated during electrophoresis is removed into the cooled region by pressure or by a low-strength electric field to save it from exposure to the elevated Capillary electrophoresis (CE) serves as a platform for a large family of temperature-sensitive affinity

Krylov, Sergey

410

Capillary-Driven Heat Transfer Experiment: Keeping It Cool in Space  

NASA Technical Reports Server (NTRS)

Capillary-pumped loops (CPL's) are devices that are used to transport heat from one location to another--specifically to transfer heat away from something. In low-gravity applications, such as satellites (and possibly the International Space Station), CPL's are used to transfer heat from electrical devices to space radiators. This is accomplished by evaporating one liquid surface on the hot side of the CPL and condensing the vapor produced onto another liquid surface on the cold side. Capillary action, the phenomenon that causes paper towels to absorb spilled liquids, is used to "pump" the liquid back to the evaporating liquid surface (hot side) to complete the "loop." CPL's require no power to operate and can transfer heat over distances as large as 30 ft or more. Their reliance upon evaporation and condensation to transfer heat makes them much more economical in terms of weight than conventional heat transfer systems. Unfortunately, they have proven to be unreliable in space operations, and the explanation for this unreliability has been elusive. The Capillary-Driven Heat Transfer (CHT) experiment is investigating the fundamental fluid physics phenomena thought to be responsible for the failure of CPL's in low-gravity operations. If the failure mechanism can be identified, then appropriate design modifications can be developed to make capillary phase-change heat-transport devices a more viable option in space applications. CHT was conducted onboard the Space Shuttle Columbia during the first Microgravity Science Laboratory (MSL-1) mission, STS-94, which flew from July 1 to 17, 1997. The CHT glovebox investigation, which was conceived by Dr. Kevin Hallinan and Jeffrey Allen of the University of Dayton, focused on studying the dynamics associated with the heating and cooling at the evaporating meniscus within a capillary phase-change device in a low-gravity environment. The CHT experimental hardware was designed by a small team of engineers from Aerospace Design & Fabrication (ADF), the NASA Lewis Research Center, and the University of Dayton. The hardware consisted of two experiment modules that each contained an instrumented test loop (idealized capillary-pumped loop), a base unit for power conversion and backlighting, a display unit with 15 LED's (light-emitting diodes) to display temperatures, pressure, heater power, and time, a control unit to select heaters and heater settings, a cooling fan, and associated cables.

Lekan, Jack F.; Allen, Jeffrey S.

1998-01-01

411

Effects of a layer of vegetative ash layer on wettable and water repellent soil hydrology  

NASA Astrophysics Data System (ADS)

Following a wildfire, a layer of vegetative ash often covers the ground until it is dissolved or redistributed by wind and water erosion. Much of the existing literature suggests that the ash layer temporally reduces infiltration by clogging soil pores or by forming a surface crust (Mallik et al., 1984; Onda et al., 2008). However, an increasing number of field-based studies have found that, at least in the short term, ash increases infiltration by storing rainfall and protecting the underlying soil from sealing (Cerd and Doerr, 2008; Woods and Balfour, 2008). On the other hand, after a fire the soil may have produced, enhanced or reduced its water repellency (Doerr et al., 2000). Very few studies have been taken into account the interaction of the ash and the repellent soil. The layer of ash may have similar role as a litter layer in delaying runoff and reducing erosion by storing water. In order to examine this interaction, it was been made a series of experiments using a laboratory rainfall simulation. It has been assessed the effects of an ash layer i) on a wettable and water repellent soil (WDPT > 7200s), ii) with different ash thicknesses (bare soil and 5 mm, 15 mm and 30 mm of ash), iii) preceding and following the first rain after a fire when the ground is still wetted and after being partially dried. Three replicates were done, being a total of 40 simulations. The ash used was collected from a Wildfire in Teruel (Spain) during summer of 2009. The simulations were conducted in metal boxes of 30x30 cm and filled with 3 cm of soil. The slope of the box was set at 10 (17%) and the intensity applied was 78-84 mm h-1during 40 minutes. The splash detachment was determined also using four splash cups. Overland flow and subsurface drainage was collected at 1-minute intervals and the former stored every 5 min to allow determination of sediment concentrations, yield and erosion rates. Each sample was examined at the end in terms of water repellency, infiltration pattern and ash incorporation into the soil. The results show that when ash covers the wettable soil, runoff occur for a short period of time in the middle of the event. It occurred latter on time but larger in quantity as the ash thickness increases (from 0% to 2% of runoff coefficient) and at the same time drainage is reduced (from 57 to 24%). This suggests that the ash layer became saturated and produce runoff until the water is able to drain into the soil. Oppositely, in water repellent soil as ash thickness increases both runoff is reduced (from 78% to 26%) and drainage is increased (from 0 to 16%). That fact indicates a modification in the hydraulic conductivity of the repellent soil due to the pressure of the ash layer. Splash and erosion rates are bigger in water repellent soils yet erosion rates never exceed 2.5 g m-2 h-1. The fact of wetting increases the runoff and drainage rates in wettable but reduce them in the water repellent soil. An irregular infiltration pattern is observed afterwards. After drying the soil, the increase in runoff indicates a crust formation. Moreover, in water repellent soils part of the repellency is reestablished. These findings demonstrate that the interaction of the soil-ash layer should be considered and better studied in the immediate hydrological response after wildfire due to its particular behavior. References Cerd, A. and Doerr, S.H., 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74: 256-263. Doerr, S.H., Shakesby, R.A. and Walsh, R.P.D., 2000. Soil Water repellency: Its causes, characteristics and hydro-geomorphological significance. Earth Science Reviews, 51: 33-65. Mallik, A.U., Gimingham, C.H. and Rahman, A.A., 1984. Ecological effects of heater burning. I. Water infiltration, moisture retention and porosity of surface soil. Journal of Ecology, 72: 767-776. Onda, Y., Dietrich, W.E. and Booker, F., 2008. Evolution of overland flow after a severe forest fire, Point Reyes, California. Catena, 72: 13-20. Woods, S.W. and Balfour, V., 2008. The

Bod, Merche B.; Doerr, Stefan H.; Cerd, Artemi; Mataix-Solera, Jorge

2010-05-01

412

Metallized Capillaries as Probes for Raman Spectroscopy  

NASA Technical Reports Server (NTRS)

A class of miniature probes has been proposed to supplant the fiber-optic probes used heretofore in some Raman and fluorescence spectroscopic systems. A probe according to the proposal would include a capillary tube coated with metal on its inside to make it reflective. A microlens would be hermetically sealed onto one end of the tube. A spectroscopic probe head would contain a single such probe, which would both deliver laser light to a sample and collect Raman or fluorescent light emitted by the sample.

Pelletier, Michael

2003-01-01

413

Characterization of protein conjugates using capillary electrophoresis.  

PubMed

With the aim of generating antibodies, a calix[4]arene-crown-6 was coupled to bovine serum albumin. For that purpose, a complete procedure to optimize and characterize the coupling of hydrophobic haptens based on capillary electrophoresis (CE) was developed. We demonstrated the existence of a polynomial relationship between the electrophoretic mobility (mu(ep)) and the hapten density. This correlation was used not only to study the coupling reaction in terms of optimization and kinetics but also to determine the average coupling molar ratio of any given conjugate. An estimation of the heterogeneity of these conjugates by simulation of experimental peaks was also proposed. PMID:17964582

Safi, Samir; Asfari, Zouhair; Hagge, Agns

2007-11-30

414

Numerical simulation of nonisothermal capillary interfaces  

SciTech Connect

An effective algorithm for analysis of nonisothermal capillary interfaces has been developed. The algorithm is based on a coordinate transformation method. The unknown physical domain is mapped on to a rectangular computational domain, with the explicit form of the mapping function not being known. The field variables and the mapping function are determined simultaneously using Picard-type iteration. The algorithm is based on the second-order finite difference discretization and delivers the second-order accuracy, even for very large interfacial distortions. 7 refs., 7 figs., 2 tabs.

Chen, C.; Floryan, J.M. (Univ. of Western Ontario, London, Ontario (Canada))

1994-03-01

415

Capillary-Pumped Heat-Transfer Loop  

NASA Technical Reports Server (NTRS)

New type of capillary-pumped heat-transfer loop primes itself at startup. Removes substantial quantities of heat like that generated by people and equipment in rooms and vehicles. Creates continuous path for its working fluid; both vapor and liquid move in same direction. Key element in operation of loop is formation of slugs of liquid, condensed from vapor and moved along loop by vapor bubbles before and after it. Both evaporator and condenser contain axial arteries carrying water. Heat entering evaporator from heat source provides energy for transport of fluid and heat. Dimensions in inches.

1989-01-01

416

Capillary Network, Cancer and Kleiber Law  

E-print Network

We develop a heuristic model embedding Kleiber and Murray laws to describe mass growth, metastasis and vascularization in cancer. We analyze the relevant dynamics using different evolution equations (Verhulst, Gompertz and others). Their extension to reaction diffusion equation of the Fisher type is then used to describe the relevant metastatic spreading in space. Regarding this last point, we suggest that cancer diffusion may be regulated by Levy flights mechanisms and discuss the possibility that the associated reaction diffusion equations are of the fractional type, with the fractional coefficient being determined by the fractal nature of the capillary evolution.

Dattoli, G; Licciardi, S; Guiot, C; Deisboeck, T S

2014-01-01

417

An investigation of wetting phase evaporation from capillary porous matrices  

NASA Astrophysics Data System (ADS)

Drying of porous materials is important to a wide variety of applications spanning art, architecture, cooking, agriculture, and engineering. To better understand the phenomenon, we used low-field NMR relaxometry to gain insight into the behavior of air and water within the individual pores during drying. We applied a singular value decomposition algorithm to invert low-field NMR CPMG T2 data into apparent pore size distributions and measured the drying rates and the changes in relaxation distributions for alumina matrices of differing pore sizes and for sandstones. We observed two regions of constant drying rate with a large, sharp break in slope when the wetting phase saturation became discontinuous. In both regimes, the surface evaporation rate was controlled by capillary wicking action. Moreover, the drying rate in the early regime was greatly enhanced over evaporation from bulk fluid. The continuous decrease in mean T2 of the sample during drying suggests that air penetrates along the pore centers while leaving water wetting the pore walls.

Lee, Curtis; White, Jessica; Sansom, Aaron; Davis, Lorne

2009-10-01

418

Evaluation of pulsatile and nonpulsatile flow in capillaries of goat skeletal muscle using intravital microscopy.  

PubMed

It is commonly believed that pulsatile flow generated by the pumping action of the heart is dampened out by the time it reaches the microcirculation. In clinical practice, most of the cardiopulmonary bypass pumps and ventricular assist devices are nonpulsatile. To test the hypothesis that pulsatile flow generated by the heart does exist at the microvascular level, intravital microscopy of a large animal model (goat) was developed to visualize and to videorecord the surface microcirculation of the flexor carpi ulnaris muscle from the right forelimb. Density of perfused capillaries and red blood cell velocity in capillaries were measured in five goats during pulsatile perfusion provided by the heart and during a subsequent 3-hr period of nonpulsatile perfusion provided by a centrifugal ventricular assist device (Centrimed, Sarns 3M) that bypassed the heart. Throughout the experiment, the heart rate, innominate artery mean blood pressure, and flow remained unchanged. During the pulsatile regimen, velocities showed regular fluctuations that coincided with the period of the cardiac cycle (range of periods: 0.5-0.8 sec). The peak velocity amplitudes (range: 0.25-0.55 mm/sec) correlated directly with the amplitude of the pulse pressure. During the nonpulsatile regimen, no such correlations were seen. During pulsatile flow and during the 3-hr nonpulsatile period, capillary density remained stable at 24 capillaries/mm of test line but there were significant increases in red cell velocity, from 0.8 to 1.2 mm/sec (P < 0.05), and in coefficient of variation of velocity (used as an index of flow heterogeneity), from 19 to 34% (P < 0.05). We conclude that (1) pulsatility exists in the capillary bed and that it directly correlates with the pumping action of the heart and (2) nonpulsatile flow produced by the ventricular assist device does not cause an acute deterioration in microvascular perfusion. We interpret the increase in heterogeneity of flow as an early sign of microvascular dysfunction. Prolonged use of the nonpulsatile device may, therefore, lead to deterioration in perfusion that could compromize the function of the organ. PMID:7731396

Lee, J J; Tyml, K; Menkis, A H; Novick, R J; Mckenzie, F N

1994-11-01

419

Functional groups grafted nonwoven fabrics for blood filtration-The effects of functional groups and wettability on the adhesion of leukocyte and platelet  

NASA Astrophysics Data System (ADS)

In this work, the effects of grafted functional groups and surface wettability on the adhesion of leukocyte and platelet were investigated by the method of blood filtration. The filter materials, poly(butylene terephthalate) nonwoven fabrics bearing different functional groups including hydroxyl (OH), carboxyl (COOH), sulfonic acid group (SO3H) and zwitterionic sulfobetaine group (?N((CH3)2)(CH2)3SO3?) with controllable wettability were prepared by UV radiation grafting vinyl monomers with these functional groups. Our results emphasized that both surface functional groups and surface wettability had significant effects on the adhesion of leukocyte and platelet. In the case of filter materials with the same wettability, leukocytes adhering to filter materials decreased in the order: the surface bearing OH only > the surface bearing both OH and COOH > the surface bearing sulfobetaine group > the surface bearing SO3H, while platelets adhering to filter materials decreased as the following order: the surface bearing SO3H > the surface bearing both OH and COOH > the surface bearing OH only > the surface bearing sulfobetaine group. As the wettability of filter materials increased, both leukocyte and platelet adhesion to filter materials declined, except that leukocyte adhesion to the surface bearing OH only remained unchanged.

Yang, Chao; Cao, Ye; Sun, Kang; Liu, Jiaxin; Wang, Hong

2011-01-01

420

The research about the time-effect of the wettability on the wool surface treated by the Ar plasma jet in the atmospheric pressure  

NASA Astrophysics Data System (ADS)

A facility which is called atmospheric pressure and normal temperature plasma jet was introduced in this paper. After the wool surface was treated by this kind of facility with Ar in different irradiating times, the time-effect of the fabric wettability has been weakened, and if the parameters of the irradiating time and the voltage of the facility are appropriate, the time-effect of wettability can be effectively inhibited. With the stable wettability, the fabric can be dressed without PVA (polyvinyl alcohol) which can cause lager pollution in the textile field, so the method without the time-effect of the textile wettability will be useful in the field of clean textile production. Undoubtedly, the stable wettability of textile surface was caused by the stable hydrophilic molecules on the textile surface. Thus, the reaction process and results on the textile surface treated by plasma needs to be studied to optimize the parameters of the irradiating time and the voltage of the plasma jet. So the initial experimental studies on the optimization of the parameters of the plasma jet were discussed in this paper, and the authors believe that the method without the time-effect also can be used in other fields of plasma application.

Yu, Wu; Shouguo, Wang

2009-09-01

421

The permeability of single capillaries to potassium ions  

PubMed Central

This paper reports a description of methods for determining the diffusional permeability to potassium ions of single capillaries in the frog mesentery. By means of micropipettes, injections or infusions were delivered into a single capillary. The subsequent concentration variations in and about the capillary were followed with K(+)-sensitive microelectrodes. A theoretical analysis is provided which give a quantitative frame of reference for evaluating the observed time-concentration curves in terms of capillary permeability. The advantage of single capillary studies is that the surface area through which diffusion occurs is known as is the concentration difference across the capillary membrane. Three different techniques are: (a) the single injection method which represents an application of the indicator diffusion technique where a high-K(+) bolus is injected into a single capillary; (b) the sack method which determines the rate of K(+) disappearance from within and immediately outside an occluded capillary segment, after a brief increase in intracapillary K(+) concentration; and (c) the interstitial diffusion method which records time and spatial distribution of K(+) in the interstitial space after a step-change in intracapillary K(+) concentration. The methods gave an average potassium permeability of the capillary membrane of 67x10(-5) cm s(-1) (SD: 23, n=26) at room temperature. These figures are clearly higher than those previously reported in mammalian capillary studies using whole-organ techniques. In terms of the pappenheimer pore model, this estimate of capillary permeability is consistent with the behavior of a membrane with a thickness of 1.0 ?m which possesses equivalent pores with a radius of 110 A, a fractional pore area of 0.3 percent, and a pore density of 8 ?m(-2). PMID:641520

Crone, C; Frokjaer-Jensen, J; Friedman, JJ; Christensen, O

1978-01-01

422

Microfluidic Device to Culture 3D In Vitro Human Capillary Networks  

E-print Network

Microfluidic Device to Culture 3D In Vitro Human Capillary Networks Monica L. Moya, Luis F. Alonzo human capillaries. Keywords: Microfluidic platform, Microenviroment, Perfused capillary networks perfusion. To address these limitations, various research groups have explored the use of microfluidic

George, Steven C.

423

Journal of Chromatography B, 841 (2006) 313 Capillary electromigration methods for the study of collagen  

E-print Network

Journal of Chromatography B, 841 (2006) 3­13 Review Capillary electromigration methods, micellar electrokinetic chromatography as well as combinations of HPLC and capillary electrophoresis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2. Micellar electrokinetic chromatography and capillary gel electrophoresis

Miksik, Ivan

424

Single-step sandwich immunoreaction in a square glass capillary immobilizing capture and enzyme-linked antibodies for simplified enzyme-linked immunosorbent assay.  

PubMed

To simplify the complicated operation steps and to minimize sample and reagent amounts for enzyme-linked immunosorbent assays (ELISA), we developed a square glass capillary immunosensor containing both covalently immobilized capture antibodies and physically adsorbed enzyme-linked antibodies. The immobilization of capture antibodies (anti-human IgG) was carried out by the treatment of 3-aminopropyltriethoxy silane, glutaraldehyde, and protein-A, followed by affinity capture of the antibody. In contrast, the enzyme-linked antibodies (alkaline phosphatase (ALP)-linked anti-human IgG) were physically adsorbed on the four corners of the capillary with the aid of polyethylene glycol (PEG) acting as a scaffold. A nanoliter volume of antigen (human IgG)-containing sample solution was introduced via capillary action. This addition resulted in the release and diffusion of ALP-linked anti-human IgG into the bulk solution. This event led to a 20-min single-step sandwich immunoreaction at the inner wall of capillary; the reaction was detected through the reaction with fluorescein diphosphate (FDP) which generated a fluorescent product, fluorescein. Using this technique, we obtained an intra-capillary precision with a coefficient of variation of 9.7%. In addition, the specificity study showed that the human IgG capillary immunosensor did not respond to rabbit IgG. Quantitative analysis was possible within the response range of 10 - 5000 ng mL(-1) anti-human IgG. This capillary immunosensor can act as a single analytical unit or can be integrated into a capillary array for multiple bioanalysis. PMID:22232224

Tsutsumi, Erina; Henares, Terence G; Funano, Shun-ichi; Kawamura, Kunio; Endo, Tatsuro; Hisamoto, Hideaki

2012-01-01

425

Quaternized cellulose-supported gold nanoparticles as capillary coatings to enhance protein separation by capillary electrophoresis.  

PubMed

Gold nanoparticles (Au NPs) were synthesized and stabilized by using water-soluble quaternized cellulose (QC) as support matrix through a straightforward and environmentally friendly aqueous-phase approach. The structure and morphology of QC-supported Au NPs (QC-Au NPs) were investigated systematically by UV-visible, FT-IR, x-ray diffraction and TEM measurement. The Au NPs with mean diameter of about 7nm were shown to efficiently redisperse in water due to the strong interaction between QC and Au NPs, and the solutions were quite stable after storage for nearly 4 months at room temperature. QC-Au NPs were subsequently used as novel physically adsorbed coatings for protein separation by CE. The separation performance was significantly improved in the capillary coated by QC-Au NPs compared with that of the uncoated capillary or QC coated capillary. A small quantity of Au NPs (Au content of 4.6%) was adequate for the obvious improvement of coating ability. The theoretical plate number of lysozyme in QC-Au1 NPs coated capillary was 2.9 times as much as that in QC coated capillary. We have demonstrated the separation of six model proteins with RSD of migration time less than 2.79% and RSD of peak area less than 4.81%. Furthermore, QC-Au NPs was applied to the analysis of closely related proteins and biological samples. With simplicity, high resolution and reproducibility, the proposed method shows potential for applications in proteomics and clinical diagnosis. PMID:24745845

You, Jun; Zhao, Lingguo; Wang, Gongwei; Zhou, Haitao; Zhou, Jinping; Zhang, Lina

2014-05-23