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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

Capillary Action  

NSDL National Science Digital Library

Capillary Action: In this section of USGS Water Science for School's you will learn how capillary action is important for moving water (and all of the things that are dissolved in it) around. It is defined as the movement of water within the spaces of a porous material due to the forces of adhesion, cohesion, and surface tension.

2008-05-28

3

Silicon Ribbon Growth by a Capillary Action Shaping Technique.  

National Technical Information Service (NTIS)

The crystal growth method described is a capillary action shaping technique. 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 materi...

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

1976-01-01

4

Silicon Ribbon Growth by a Capillary Action Shaping Technique.  

National Technical Information Service (NTIS)

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 replacem...

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

1977-01-01

5

Silicon ribbon growth by a capillary action shaping technique  

Microsoft Academic Search

The crystal growth method described is a capillary action shaping technique. 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. A capillary die is so designed that the bounding edges of the die top are not parallel or concentric with the growing

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

1976-01-01

6

The effect of wettability on capillary fracturing in granular media  

NASA Astrophysics Data System (ADS)

During multiphase flow in a granular medium, capillary pressures can overcome cohesive forces between the grains and cause grain displacements that macroscopically resemble fracture patterns. These patterns were recently studied in experiments of air displacing water in a thin bed of glass beads, for which air is a strongly non-wetting fluid (Holtzman et al. 2012). The experiments showed that the transition from viscous fingering and capillary fingering to capillary fracturing could be predicted by a single dimensionless number called the fracturing number, which is the ratio of the capillary forces that promote grain displacements to the frictional forces that resist displacements. Here, we extend those experiments to study exclusively how the wettability of the invading fluid affects fracturing by visually observing the morphology of the pattern. As in the previous work, we inject a less viscous fluid into a thin bed of glass beads saturated with a more viscous fluid. However, we now vary the fluids to change the wettability of the invading fluid from perfectly non-wetting to wetting. We hypothesize that the emergence of fracturing can be predicted by a modified fracturing number that includes the contact angle to account for the effect of wettability on the capillary pressure. Since the contact angle is a function of the capillary number, we expect the emergence of fracturing will depend on the capillary number when the invading fluid is partially wetting.

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

2012-12-01

7

Silicon Ribbon Growth by a Capillary Action Shaping Technique. Quarterly Technical Progress Report Number 7.  

National Technical Information Service (NTIS)

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 die. As ribbon growth depletes the melt meniscus, capillary action supplies replacem...

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

1977-01-01

8

Silicon ribbon growth by a capillary action shaping technique  

Microsoft Academic Search

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

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

1977-01-01

9

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

SciTech Connect

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

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

2008-06-30

10

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

11

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

12

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

13

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

14

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

SciTech Connect

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

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

2006-02-01

15

Silicon Ribbon Growth by a Capillary Action Shaping Technique. Final Report, May 8, 1975--November 8, 1977.  

National Technical Information Service (NTIS)

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 die. As ribbon growth depletes the melt meniscus, capillary action supplies replacem...

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

1977-01-01

16

Quantum Capillary Action  

Microsoft Academic Search

For many years it has been widely accepted that Capillary Action as seen in plants was best calculated using a classical method. Recent experiments with carbon nanotubes seem to suggest that a Quantum Mechanical explanation may now be appropriate. The suggested use of Carbon nanotubes as steering mechanisms for particle accelerators may reveal a better model using Quantum mechanics.

Richard Kriske

2008-01-01

17

Capillary Action Around Dental Structures  

Microsoft Academic Search

The capillary action of saliva occurs in the crevices around and between teeth and around dental restorations. Marginal leakage and denture retention caused by a thin film of saliva are aspects of capillary phenomena. Liquids in capillaries isolated from a reservoir showed an increase in surface tension and lower vapor pressure. The strength of thin films of human saliva was

W. J. OBrien

1973-01-01

18

Silicon ribbon growth by a capillary action shaping technique  

NASA Technical Reports Server (NTRS)

The crystal growth method described is a capillary action shaping technique. 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. A capillary die is so designed that the bounding edges of the die top are not parallel or concentric with the growing ribbon. The new dies allow a higher melt meniscus with concomitant improvements in surface smoothness and freedom from SiC surface particles, which can degrade perfection.

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

1976-01-01

19

Silicon ribbon growth by a capillary action shaping technique. Final report, May 8, 1975November 8, 1977  

Microsoft Academic Search

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 die. As ribbon growth depletes the melt meniscus, capillary action supplies replacement material. The objective of the work is to attain a clear technological assessment of silicon ribbon growth by the capillary action shaping

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

1977-01-01

20

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

21

Silicon ribbon growth by a capillary action shaping technique. Quarterly technical progress report number 7  

Microsoft Academic Search

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 die. As ribbon growth depletes the melt meniscus, capillary action supplies replacement material. Progress in 50-mm-wide ribbon growth is detailed. Over 11 meters of uniform 50-mm-wide ribbon have been grown this quarter. Fuller advantage has

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

1977-01-01

22

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

23

Capillary, wettability and interfacial dynamics in polymer electrolyte fuel cells  

SciTech Connect

In the present scenario of a global initiative toward a sustainable energy future, the polymer electrolyte fuel cell (PEFC) has emerged as one of the most promising alternative energy conversion devices for different applications. Despite tremendous progress in recent years, a pivotal performance/durability limitation in the PEFC arises from liquid water transport, perceived as the Holy Grail in PEFC operation. The porous catalyst layer (CL), fibrous gas diffusion layer (GDL) and flow channels play a crucial role in the overall PEFC performance due to the transport limitation in the presence of liquid water and flooding phenomena. Although significant research, both theoretical and experimental, has been performed, there is serious paucity of fundamental understanding regarding the underlying structure-transport-performance interplay in the PEFC. The inherent complex morphologies, micro-scale transport physics involving coupled multiphase, multicomponent, electrochemically reactive phenomena and interfacial interactions in the constituent components pose a formidable challenge. In this paper, the impact of capillary transport, wetting characteristics and interfacial dynamics on liquid water transport is presented based on a comprehensive mesoscopic modeling framework with the objective to gain insight into the underlying electrodynamics, two-phase dynamics and the intricate structure-transport-interface interactions in the PEFC.

Mukherjee, Partha P [Los Alamos National Laboratory

2009-01-01

24

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

NASA Astrophysics Data System (ADS)

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

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

2006-05-01

25

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

PubMed

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

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

2012-12-11

26

Building a Capillary Action Water Clock.  

ERIC Educational Resources Information Center

Describes a lesson plan for teachers of grades 2-8 to build a capillary action water clock. Includes a list of objectives, a list of skills/concepts addressed, a rationale for inclusion in the curriculum, and an illustrated lesson outline. (Author/MM)

Tracy, Dyanne M.

2002-01-01

27

Capillary Action in Impregnated Paper Insulation  

Microsoft Academic Search

The capillary rise of oil in vertical strips of impregnated paper obeys the same law as the rise of liquids in capillary tubes of circular cross section. From the viscosity and surface tension of an oil and its rate of rise in a given paper, it is possible to compute the ``effective capillary radius'' of the capillary pores of the

J. B. Whitehead; E. W. Greenfield

1932-01-01

28

Determination of the wettability of powders by the Washburn capillary rise method with bed preparation by a centrifugal packing technique.  

PubMed

The Washburn capillary rise method is a standard technique for determining the wettability of powders expressed as a contact angle. The method requires the preparation of two identical beds of powder. One of these beds is used to follow the capillary rise with a perfectly wetting liquid (contact angle = 0) giving access to a bed structure parameter. The other bed is used with the liquid of interest (contact angle not = 0) and the capillary rise data is analysed using the previously determined structure parameter to obtain the contact angle. In the experiments reported here we have used a centrifugal packing technique to prepare beds of powder. This gives reproducible packings and also allows a certain degree of control of the bed porosity. In addition the air permeability of the beds is also determined prior to the capillary rise experiments. The results show that the value of the contact angle of a powder determined by the Washburn method depends on the porosity of the powder bed, and that the structure parameter can be determined from the air permeability using the Kozeny-Carman expression. PMID:20362998

Galet, Laurence; Patry, Severine; Dodds, John

2010-06-15

29

Wettability measurements on plasma treated synthetic fabrics by capillary rise method  

Microsoft Academic Search

The capillary rise method was applied to evaluate the improvement in water uptake of polyester and acrylic fabrics obtained by plasma treatment. Power, exposure time and gas type (nitrogen, air and oxygen) were considered as plasma variables. After plasma treatment, fabric samples were tested through capillary rise of water. The processing of a set of height absorption values vs. time,

F Ferrero

2003-01-01

30

Anisotropic behavior of the capillary action in flip chip underfill  

Microsoft Academic Search

An underfill encapsulant can be used to improve the long-term reliability of flip chip interconnecting system by filling the gap between the chip and substrate around the solder bumps. The underfill encapsulant was filled by a capillary flow. This study was devoted to investigate the anisotropic effects of the capillary action induced by the solder bumps. A modified Hele–Shaw flow

Wen-bin Young

2003-01-01

31

Silicon Ribbon Growth by a Capillary Action Shaping Technique.  

National Technical Information Service (NTIS)

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 geom...

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

1977-01-01

32

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

SciTech Connect

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

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

1998-01-01

33

Capillary driven flow along interior corners formed by planar walls of varying wettability  

Microsoft Academic Search

Closed-form analytic solutions useful for the design of capillary flows in a variety of containers possessing interior corners\\u000a were recently collected and reviewed. Low-g drop tower and aircraft experiments performed at NASA to date show excellent agreement\\u000a between theory and experiment for perfectly wetting fluids. The analytical expressions are general in terms of contact angle,\\u000a but do not account for

M. M. Weislogel; C. L. Nardin

2005-01-01

34

Two Contrasting Theories of Capillary Action  

Microsoft Academic Search

Two theories regarding the mechanism of the rise of a liquid in a capillary tube appear in current textbooks of physics and physical chemistry. In one theory the rise is attributed to hydrostatic pressure; in the other, the liquid is drawn up the tube by a climbing meniscus. Evidence is presented in favor of the latter theory.

Ernest K. Chapin

1959-01-01

35

Wettability of nanoengineered dual-roughness surfaces fabricated by UV-assisted capillary force lithography.  

PubMed

Micro- and nanoscale combined hierarchical polymer structures were fabricated by UV-assisted capillary force lithography. The method is based on the sequential application of engraved polymer molds with a UV-curable resin of polyurethane acrylate (PUA) followed by surface treatment with a trichloro(1H,1H,2H,2H-perfluorooctyl) silane in vapor phase. Two distinct wetting states were observed on these dual-roughness structures. One is "Cassie-Wenzel state" where a water droplet forms heterogeneous contact with microstructures and homogeneous contact with nanostructures. The other is "Cassie-Cassie state" where a droplet makes heterogeneous contact both with micro- and nanostructures. A simple thermodynamic model was developed to explain static contact angle, hysteresis, and wetting transition on dual-roughness structures. PMID:19656522

Jeong, Hoon Eui; Kwak, Moon Kyu; Park, Chan Ick; Suh, Kahp Yang

2009-11-01

36

The effects of wettability and trapping on relationships between interfacial area, capillary pressure and saturation in porous media: A pore-scale network modeling approach  

NASA Astrophysics Data System (ADS)

SummaryWe use a three-dimensional mixed-wet random pore-scale network model to investigate the impact of wettability and trapping on the relationship between interfacial area, capillary pressure and saturation in two-phase drainage and imbibition processes. The model is a three-dimensional network of interconnected pores and throats of various geometrical shapes. It allows multiple phases to be present in each capillary element in wetting and spreading layers, as well as occupying the center of the pore space. Two different random networks that represent the pore space in Berea and a Saudi Arabia reservoir sandstone are used in this study. We allow the wettability of the rock surfaces contacted by oil to alter after primary drainage. The model takes into account both contact angle and trapping hystereses. We model primary oil drainage and water flooding for mixed-wet conditions, and secondary oil injection for a water-wet system. The total interfacial area for pores and throats are calculated when the system is at capillary equilibrium. They include contributions from the arc menisci (AMs) between the bulk and corner fluids, and from the main terminal menisci (MTMs) between different bulk fluids. We investigate hysteresis in these relationships by performing water injection into systems of varying wettability and initial water saturation. We show that trapping and contact angle hystereses significantly affect the interfacial area. In a strongly water-wet system, a sharp increase is observed at the beginning of water flood, which shifts the area to a higher level than primary drainage. As we change the wettability of the system from strongly water-wet to strongly oil-wet, the trapped oil saturation decreases significantly. Starting water flood from intermediate water saturations, greater than the irreducible water saturation, can also affect the non-wetting phase entrapment, resulting in different interfacial area behaviors. This can increase the interfacial area significantly in oil-wet systems. A qualitative comparison of our results with the experimental data available in literature for glass beads shows, with some expected differences, an encouraging agreement. Also, our results agree well with those generated by the previously developed models.

Raeesi, Behrooz; Piri, Mohammad

2009-10-01

37

Mobile electrons on a helium film supported by capillary action  

Microsoft Academic Search

A thick film of liquid 4He is suspended by the effect of capillary action on an array of small discs. A two-dimensional electron system (2DES) has been realized on this film. Using standard low-frequency impedance measurements it could be established that the electrons remain mobile when passing from the regime of a bulk liquid to a suspended film. Using these

P. K. H. Sommerfeld; R. W. Van Der Heijden

1995-01-01

38

Silicon ribbon growth by a capillary action shaping technique  

NASA Technical Reports Server (NTRS)

The technique of silicon ribbon growth by the capillary action shaping is assessed for applicability to photovoltaic power device material. Ribbons 25 mm in width and up to 0.5 m in length have been grown from SiC dies, and some new characteristics of growth from such dies have been identified. Thermal modifiers have been studied, and systems were developed which reduce the frozen-in stress un silicon ribbons and improve the thickness uniformity of the ribbons. Preliminary spreading resistance measurements indicate that neither surface striations nor twin boundaries give rise to appreciable resistivity variations, but that large-angle grain boundaries cause local resistivity increases of up to 200%.

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

1976-01-01

39

Interface Motion Driven by Capillary Action in Circular and Rectangular Microchannel  

Microsoft Academic Search

In microchannel flow, gas–liquid interface behavior will be important for developing a wide range of microfluidic applications, especially in micro reactors. In this article, we discuss some topics related to capillary action and two-phase fluid behavior in a microchannel. One of the topics is interface motion in the flow driven only by capillary action. We examined circular and rectangular microchannels

Naoki Ichikawa; Ryutaro Maeda

2005-01-01

40

Algorithms in Series Form for the Calculation of Capillary Action in Cylindrical Tubes  

Microsoft Academic Search

Algorithms in series form are derived, suitable for computer calculation of capillary action in vertical cylindrical tubes. Concerning the capillary depression of mercury barometers and manometers they are shown to give, in the entire range of practical interest, results at least as accurate as tables based on numerical integration. They have, however, far more general application, since with their help

J. F. Ury

1969-01-01

41

Flow of air through a capillary under the action of ultrasound  

Microsoft Academic Search

The results of an experimental investigation of the motion of air in capillary tubes under the action of ultrasound are presented. A qualitative description of the mechanism responsible for the phenomenon is proposed.

N. P. Migun; P. P. Prokhorenko

1978-01-01

42

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 36°C 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 36°C), 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

43

Silicon Ribbon Growth by a Capillary Action Shaping Technique. Quarterly Progress Report No. 3, March 15, 1976.  

National Technical Information Service (NTIS)

Objectives of the program are the technological assessment of ribbon growth of silicon by a capillary action shaping technique and economic evaluation of ribbon silicon grown by a capillary action shaping technique as low-cost silicon. The program of stud...

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

1976-01-01

44

Silicon ribbon growth by a capillary action shaping technique. Quarterly progress report No. 3, March 15, 1976  

Microsoft Academic Search

Objectives of the program are the technological assessment of ribbon growth of silicon by a capillary action shaping technique and economic evaluation of ribbon silicon grown by a capillary action shaping technique as low-cost silicon. The program of study included crystal growth of silicon ribbons, characterization of silicon ribbons, and economic evaluations and computer-aided simulation of ribbon growth. (WDM)

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

1976-01-01

45

Underfill flow as viscous flow between parallel plates driven by capillary action  

Microsoft Academic Search

Epoxy underfill is often required to enhance the reliability of flip-chip interconnects. This study evaluates the flow of filled epoxy underfill materials between parallel plates driven by capillary action. An exact model was developed to understand the functional relationship between flow distance, flow time, separation distance, surface tension, and viscosity for quasi-steady laminar flow between parallel plates. The model was

Matthew K. Schwiebert; William H. Leong

1995-01-01

46

Silicon Ribbon Growth by a Capillary Action Shaping Technique. Annual Report.  

National Technical Information Service (NTIS)

A new capillary action shaping technique die was designed. This new die allows improvements in surface smoothness and in SiC surface-particle density. Forty-seven ribbons greater than 0.5 meter long and 25 mm wide were grown during the last quarter. Ribbo...

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

1976-01-01

47

Underfill flow as viscous flow between parallel plates driven by capillary action  

Microsoft Academic Search

Epoxy underfill is often required to enhance the reliability of flip-chip interconnects. This study evaluates the flow of typical epoxy underfill materials between parallel plates driven by capillary action. An exact model was developed to understand the functional relationship between flow distance, flow time, separation distance, surface tension, and viscosity for quasisteady laminar flow between parallel plates. The model was

Matthew K. Schwiebert; William H. Leong

1996-01-01

48

Silicon ribbon growth by a capillary action shaping technique. Quarterly technical progress report No. 2  

Microsoft Academic Search

Progress during the second quarter of the contractual effort is described. The work performed related mainly to ribbon growth by a capillary action shaping technique and to ribbon characterization. Actual progress in the crystal growth area includes the evaluation of 10 potential die materials other than carbon and the process development for 25-mm-wide ribon. From the die study it is

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

1975-01-01

49

Drying shrinkage of concrete due to capillary action  

Microsoft Academic Search

Résumé  On explique l'action de la pression capillaire sur le retrait de la pâte de ciment et du béton. La théorie s'appuie sur les\\u000a principes de la thermodynamique et la théorie de l'élasticité.

T. C. Hansen

1969-01-01

50

Motion of a liquid droplet in a capillary under the action of static force and an acoustic field  

Microsoft Academic Search

We consider the motion of a liquid droplet inside a capillary of a porous medium under the action of a static force and an\\u000a acoustic field. We derive the equation of motion of the droplet in the capillary and analyze numerically its solution. We\\u000a show that the vibration attenuates the influence of the capillary force. Due to the effect of

V. S. Averbakh; S. N. Vlasov; Yu. M. Zaslavsky

2000-01-01

51

Silicon ribbon growth by a capillary action shaping technique. Annual report  

Microsoft Academic Search

A new capillary action shaping technique die was designed. This new die allows improvements in surface smoothness and in SiC surface-particle density. Forty-seven ribbons greater than 0.5 meter long and 25 mm wide were grown during the last quarter. Ribbon width was extended to 38 mm (1¹\\/ inches). Surface films on ribbon surfaces were analyzed as SiC crystallites. Epitaxial growth

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

1976-01-01

52

Motion of a gas inclusion in a capillary under the action of vibration  

Microsoft Academic Search

The motion of gas inclusions in a liquid-filled duct under the action of vibration for comparable cross-sectional dimensions\\u000a of the inclusion and the duct is studied. Two limiting cases of inclusion motion differing with respect to the drag mechanism\\u000a are considered. For low velocities, it is assumed that the drag is mainly determined by the capillary forces and the friction

V. S. Avduevskii; R. F. Ganiev; L. E. Ukrainskii; I. G. Ustenko

1998-01-01

53

Effect of microstructure on blood cell clogging in blood separators based on capillary action  

Microsoft Academic Search

In this study, the blood cell clogging phenomenon occurring in blood separators based on capillary action is carefully investigated\\u000a and how to minimize the reduction in plasma separation speed caused by clogging is discussed. Four different blood separators\\u000a are fabricated on optically transparent glass substrates to clearly observe the blood plasma separation and the blood cell\\u000a clogging in the microfluidic

Duckjong Kim; Jae Young Yun; Sang-Jin Park; Seung S. Lee

2009-01-01

54

Selective Growth of Polyacetylene Narrow Wires Utilizing Capillary Action of Catalyst Solution in Grooves  

Microsoft Academic Search

Polyacetylene narrow wires were selectively grown in SiO2 grooves. A substrate with grooves was held upright and the lower edge was dipped in a pool of the catalyst solution. The solution rised up in the groove by capillary action. A polyacetylene wire 0.1 mum wide, 0.2 mum thick, and 8 mm long was synthesized in a groove 0.2 mum wide

Nobuo Sasaki; Yoshihiro Takao; Nagisa Ohsako

1992-01-01

55

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

56

Silicon ribbon growth by a capillary action shaping technique. Quarterly technical progress report No. 1  

Microsoft Academic Search

Progress during the first quarter of the contractual effort is described. The work performed relates (a) to ribbon growth by a capillary action shaping technique, (b) to ribbon characterization, and (c) to economic evaluation and computer-aided simulation of ribbon growth. Actual progress includes growth of 12-mm and 25-mm-wide ribbon with individual lengths ranging from 0.12 to 1.06 meters. The growth

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

1975-01-01

57

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

58

Directly drawn organic transistors by capillary pen: a new facile patterning method using capillary action for soluble organic materials.  

PubMed

A capillary pen drawing technique, developed as a new patterning methodology for the large-area patterning and fabrication of organic electronics, provides several advantages over conventional approaches: the method is simple and versatile, there are no restrictions on the patterning shapes that could be produced, and the method can be tailored to a variety of substrates. PMID:23696024

Kang, Boseok; Min, Honggi; Seo, Unsuk; Lee, Junghwi; Park, Namwoo; Cho, Kilwon; Lee, Hwa Sung

2013-08-14

59

Wettability contrasts between fresh and weathered diesel fuels.  

PubMed

The remediation of non-aqueous phase liquid (NAPL) contaminated sites is impeded due to subsurface complexities, including wettability. Wettability quantifies which of two immiscible fluids preferentially coats a solid. At most contaminated sites water-wetting conditions are typically assumed despite mounting evidence that this is not always the case. In this study, wettability was examined for two NAPL samples of contrasting origin: a fresh and a field sample. Wettability was assessed through (i) cyclical, 'cumulative elapsed contact time' intrinsic contact angle measurements, (ii) interface jar tests, and (iii) cyclical, pseudo-static capillary pressure-saturation curves. The work as a whole demonstrated that while the fresh diesel sample was consistently water-wet, the field diesel sample exhibited repeatable cycles of wettability reversal between water drainage and imbibition. And while wettability hysteresis increased with contact time for the field diesel, the occurrence of wettability reversal at each change of saturation direction was independent of contact time. Such behavior is not easily assessed by standard wettability indices. Moreover, it contrasts with the permanent wettability alteration observed for complex organics (e.g., coal tar) observed in most studies. It is hypothesized that the cyclical wettability reversal is related to cyclical changes in intermediate pore wettability due to sorption of surface active compounds (causing NAPL-wetting imbibition) and rupturing of the soil grain water film (causing water-wet drainage). The wettability differences between the two NAPLs may be due to additives (i.e., a surfactant) in the original formulation and/or byproducts from subsurface weathering. These results support better characterization of site-specific wettability, improved model development and more realistic site conceptual models for improved remediation efforts. PMID:23159759

Drake, Stephanie S; O'Carroll, Denis M; Gerhard, Jason I

2013-01-01

60

Silicon ribbon growth by a capillary action shaping technique. Annual report (Quarterly technical progress report No. 9)  

Microsoft Academic Search

Progress on the technological and economical assessment of ribbon growth of silicon by a capillary action shaping technique is reported. Progress in scale-up of the process from 50 mm to 100 mm ribbon widths is presented, the use of vitreous carbon as a crucible material is analyzed, and preliminary tests of CVD SiâNâ as a potential die material are reported.

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

1977-01-01

61

Wettability hysteresis and its implications for DNAPL source zone distribution.  

PubMed

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

Ryder, Jodi L; Demond, Avery H

2008-11-14

62

Experimental investigations of the wettability of clays and shales  

Microsoft Academic Search

Wettability in argillaceous materials is poorly understood, yet it is critical to hydrocarbon recovery in clay-rich reservoirs and capillary seal capacity in both caprocks and fault gouges. The hydrophobic or hydrophilic nature of clay-bearing soils and sediments also controls to a large degree the movement of spilled nonaqueous phase liquids in the subsurface and the options available for remediation of

Artem Borysenko; Ben Clennell; Rossen Sedev; Iko Burgar; John Ralston; Mark Raven; David Dewhurst; Keyu Liu

2009-01-01

63

Anisotropic Properties of Aligned ?-Conjugated Polymer Films Fabricated by Capillary Action and Their Post-Annealing Effects  

NASA Astrophysics Data System (ADS)

Uniaxially aligned films of thiophene-based polymers were successfully fabricated by a novel film-forming method using the capillary action of polymer solutions without applying any mechanical or thermal stress to the polymers. Unique optical and electrical anisotropies were studied in the poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene) (pBTTT) and poly(2,5-bis(3-alkylthiophene-2-yl)thieno[2,3-b]thiophene) (pBTCT) films fabricated by the method. Moreover, the improvements of the optical and electrical properties of the aligned polymer films by thermal annealing were also demonstrated.

Higashi, Takuya; Yamasaki, Naoyuki; Utsumi, Hideyuki; Yoshida, Hiroyuki; Fujii, Akihiko; Ozaki, Masanori

2011-09-01

64

Anisotropic Properties of Aligned pi-Conjugated Polymer Films Fabricated by Capillary Action and Their Post-Annealing Effects  

Microsoft Academic Search

Uniaxially aligned films of thiophene-based polymers were successfully fabricated by a novel film-forming method using the capillary action of polymer solutions without applying any mechanical or thermal stress to the polymers. Unique optical and electrical anisotropies were studied in the poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene) (pBTTT) and poly(2,5-bis(3-alkylthiophene-2-yl)thieno[2,3-b]thiophene) (pBTCT) films fabricated by the method. Moreover, the improvements of the optical and electrical properties of

Takuya Higashi; Naoyuki Yamasaki; Hideyuki Utsumi; Hiroyuki Yoshida; Akihiko Fujii; Masanori Ozaki

2011-01-01

65

Silicon ribbon growth by a capillary action shaping technique. Quarterly technical progress report No. 6  

Microsoft Academic Search

The effects of capillary die design on dopant distribution are described. A new technique for thermal geometry control utilizing inert-gas purging was implemented. Routine 38-mm-wide ribbon growth was demonstrated. 50-mm-wide ribbon growth in a length over one meter was achieved. A technology projection and guide to future silicon sheet growth was completed. (WDM)

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

1976-01-01

66

Penetration of aqueous surfactant solutions and non- newtonian polymer solutions into paper by capillary action  

Microsoft Academic Search

The capillary rise of aqueous solutions of 3 surfactants in a strip of vertical filter paper has been measured. There was a quadratic relationship between the height of rise and time as expected from theory. In all cases the surfactants decreased the penetration of water into filter paper, the rate constant for penetration being roughly proportional to the ratio of

T. Gillespie; T. Johnson

1971-01-01

67

Drying patterns of porous media containing wettability contrasts.  

PubMed

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

Shokri, N; Or, D

2013-02-01

68

Capillary action in narrow and wide tubes---a unified approach  

Microsoft Academic Search

For the purpose of calculating meniscus volume, an ellipsoidal air-liquid interface has been assumed. A formula for the meniscus volume as a function of the radius (r) of a tube and capillary constant (a2) has been derived without resorting to approximations or introducing any arbitrary variable. The formula holds good for all values of r\\/a. Earlier there were two distinct

S. V. Gupta

2004-01-01

69

Scaling of spontaneous imbibition data with wettability included.  

PubMed

Wettability is a dominant parameter governing spontaneous imbibition. However less attention has been paid to the effect of wettability on the scaling of spontaneous imbibition data. Actually few models can include wettability in scaling of spontaneous imbibition data. To this end, a scaling model has been developed for NAPL (oil)-saturated porous media with different wettability based on the fluid flow mechanisms in porous media. Relative permeability, capillary pressure, initial water saturation, and wettability are considered in the scaling model. Theoretically this scaling model is suitable for both cocurrent and countercurrent spontaneous imbibition. The experimental data of countercurrent spontaneous water imbibition at different wettability cannot be scaled using the frequently used scaling model but can be scaled satisfactorily using the scaling model developed in this study. An analytical solution to the relationship between recovery and imbibition time for linear spontaneous imbibition has also been derived in the case in which gravity is ignored. The analytical solution predicts a linear correlation between the recovery by spontaneous water imbibition and the square root of imbibition time, which has been verified against experimental data. PMID:17081652

Li, Kewen

2007-01-30

70

Scaling of spontaneous imbibition data with wettability included  

NASA Astrophysics Data System (ADS)

Wettability is a dominant parameter governing spontaneous imbibition. However less attention has been paid to the effect of wettability on the scaling of spontaneous imbibition data. Actually few models can include wettability in scaling of spontaneous imbibition data. To this end, a scaling model has been developed for NAPL (oil)-saturated porous media with different wettability based on the fluid flow mechanisms in porous media. Relative permeability, capillary pressure, initial water saturation, and wettability are considered in the scaling model. Theoretically this scaling model is suitable for both cocurrent and countercurrent spontaneous imbibition. The experimental data of countercurrent spontaneous water imbibition at different wettability cannot be scaled using the frequently used scaling model but can be scaled satisfactorily using the scaling model developed in this study. An analytical solution to the relationship between recovery and imbibition time for linear spontaneous imbibition has also been derived in the case in which gravity is ignored. The analytical solution predicts a linear correlation between the recovery by spontaneous water imbibition and the square root of imbibition time, which has been verified against experimental data.

Li, Kewen

2007-01-01

71

New concept for coal wettability evaluation and modulation. Technical progress report, July 1, 1993--September 30, 1993.  

National Technical Information Service (NTIS)

The ratio of kinetics of capillary rise test between different media is a measure of relative wettability. From table 1, 2 and 3, the Hu's evaluation of wettability of five samples in the methanol, ethanol and propanol are shown that the kinetic wettabili...

W. Hu

1993-01-01

72

Infiltration of fine capillaries by a Ga-In melt under the action of ultrasound  

SciTech Connect

The authors use quartz capillary tubes of various diameters to investigate the feasibility of enhancing the diffusion of a liquid gallium-indium alloy and the ability of the alloy to impregnate sintered materials by the application of ultrasound. They discuss the diffusion variations relative to pressure, friction, surface tension, and tube diameter or pore size considerations and conclude that the use of ultrasound makes it possible, without the application of heat, to impregnate sintered materials with pore sizes ranging down to 1 micrometer with the gallium-indium alloy to depths ranging from 0.8 to 30 millimeters.

Lobova, T.A.; Bogachev, E.A.; Sarukhanov, R.G.

1987-02-01

73

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

Microsoft Academic Search

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

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

2004-01-01

74

Thermal Annealing Effects on Optical Anisotropy of Aligned Thiophene-Based ?-Conjugated Polymer Films Fabricated by Capillary Action  

NASA Astrophysics Data System (ADS)

Thermal annealing effects of the aligned thiophene-based polymer films were studied. Aligned poly{2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene} (pBTTT) and poly{2,5-bis(3-alkylthiophene-2-yl)thieno[2,3-b]thiophene} (pBTCT) films were fabricated by utilizing capillary actions of polymer solutions. The optical anisotropies of the aligned films were enhanced by thermal annealing at temperatures below the phase transition. The differences in the optical anisotropies between pBTTT and pBTCT were discussed by taking the lamellar stacking structures in the aligned films and phase transition into consideration.

Higashi, Takuya; Yamasaki, Naoyuki; Utsumi, Hideyuki; Yoshida, Hiroyuki; Fujii, Akihiko; Ozaki, Masanori

2012-02-01

75

Modeling Wettability Alteration using Chemical EOR Processes in Naturally Fractured Reservoirs  

SciTech Connect

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

Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

2007-09-30

76

Experimental investigations of the wettability of clays and shales  

NASA Astrophysics Data System (ADS)

Wettability in argillaceous materials is poorly understood, yet it is critical to hydrocarbon recovery in clay-rich reservoirs and capillary seal capacity in both caprocks and fault gouges. The hydrophobic or hydrophilic nature of clay-bearing soils and sediments also controls to a large degree the movement of spilled nonaqueous phase liquids in the subsurface and the options available for remediation of these pollutants. In this paper the wettability of hydrocarbons contacting shales in their natural state and the tendencies for wettability alteration were examined. Water-wet, oil-wet, and mixed-wet shales from wells in Australia were investigated and were compared with simplified model shales (single and mixed minerals) artificially treated in crude oil. The intact natural shale samples (preserved with their original water content) were characterized petrophysically by dielectric spectroscopy and nuclear magnetic resonance, plus scanning electron, optical and fluorescence microscopy. Wettability alteration was studied using spontaneous imbibition, pigment extraction, and the sessile drop method for contact angle measurement. The mineralogy and chemical compositions of the shales were determined by standard methods. By studying pure minerals and natural shales in parallel, a correlation between the petrophysical properties, and wetting behavior was observed. These correlations may potentially be used to assess wettability in downhole measurements.

Borysenko, Artem; Clennell, Ben; Sedev, Rossen; Burgar, Iko; Ralston, John; Raven, Mark; Dewhurst, David; Liu, Keyu

2009-07-01

77

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

78

In situ wettability determination improves formation evalution  

SciTech Connect

Wettability is an important petrophysic parameter which affects capillary pressure, relative permeability, electric properties, water cut production, waterflood behavior, and enhanced recovery. This article describes in situ wettability laboratory experiments and field studies. A laboratory model has been built with a 12-ft long 4-in. clear plastic pipe. A 1 7/8-in. slotted plastic liner has been placed on one side. Ottawa sand F-95 has been packed in the annulus either nontreated, in its naturally water wet condition, or after a silane treatment to render it oil wet. Provided in the sand pack for measurement are 12 pressure pickups with an accurate Omega digital pressure gage. A typical pressure profile recorded during oil drive in a water saturated water wet sand pack is shown. The front was left to stabilize for 60 days. A pressure profile recorded during a water drive in an oil saturated oil wet sand pack is shown. The abrupt change from the water pressure gradient can be seen clearly for the water wet and the oil wet sand. It occurs exactly as expected. The measurements show that the change occurs in less than 4 in. which is the distance between two pressure pickups.

Desbrandes, R. (Louisiana State Univ., Baton Rouge, LA (US))

1989-08-01

79

Capillary Hemangioma  

MedlinePLUS

... Conditions Frequently Asked Questions Español Condiciones Chinese Conditions Capillary Hemangioma En Español Read in Chinese What is a capillary hemangioma? A capillary hemangioma (“strawberry” birthmark) is a ...

80

Wettability of Clean Metal Surfaces.  

National Technical Information Service (NTIS)

Experimental and theoretical investigations bearing on the question of the wettability, by water, of clean oxygen-free metal surfaces are reviewed. Results on gold, silver, and copper are discussed in terms of surface cleanliness, surface structure, and e...

M. E. Schrader

1985-01-01

81

Evaluation of Reservoir Wettability and its Effect on Oil Recovery  

SciTech Connect

The objective of this five-year project are: (1) to achieve improved understanding of the surface and interfacial properties of crude oils and their interactions with mineral surfaces, (2) to apply the results of surface studies to improve predictions of oil production from laboratory measurements, and (3) to use the results of this research to recommend ways to improve oil recovery by waterflooding. During the second year of this project we have tested the generality of the proposed mechanisms by which crude oil components can alter wetting. Using these mechanisms, we have begun a program of characterizing crude oils with respect to their wettability altering potential. Wettability assessment has been improved by replacing glass with mica as a standard surface material and crude oils have been used to alter wetting in simple square glass capillary tubes in which the subsequent imbibition of water can be followed visually.

Buckley, Jill S.

1999-07-01

82

Optical switching: Capillary action  

Microsoft Academic Search

Controlling light in optical systems quickly and easily is crucial for all-optical switching. An approach that does this by exploiting the condensation of gases in a porous structure could open up new avenues in the switching field.

Yuri Kivshar

2007-01-01

83

Thin films, asphaltenes, and reservoir wettability.  

National Technical Information Service (NTIS)

Reservoir wettability impacts the success of oil recovery by waterflooding and other methods. To understand wettability and its alteration, thin-film forces in solid-aqueous-oil systems must be elucidated. Upon rupture of thick aqueous films separating th...

R. Kaminsky V. Bergeron C. J. Radke

1993-01-01

84

Capillary sample  

MedlinePLUS

... in the diagnosis of medical conditions. Capillary blood sampling offers several advantages over drawing blood from a ... sugar several times a day using capillary blood sampling. Disadvantages to capillary blood sampling include: Only a ...

85

Microvalve actuation with wettability conversion through darkness/UV application  

NASA Astrophysics Data System (ADS)

In this work a new microvalve concept that employs wettability conversion through the alternate application of darkness and UV irradiation to switch between off and on states is studied. The control of pressure drop through capillary channels by wettability conversion is the exploited control mechanism to switch in between two states. As expressed in the Young-Laplace equation the pressure drop depends on the channel diameter and contact angle (CA) of a given fluid on the channel. In this application positive pressure values obtained in the hydrophobic region are used for blocking, and negative pressure values obtained at the hydrophilic region are used for releasing water through microchannels. In both regions the magnitude of the pressure drop can be increased by very small microchannel diameters and extreme values of the contact angle (i.e. 0° and 180°). Laser microdrilling was chosen to generate the microchannels on commercially pure titanium sheets. The spatter produced by the laser drilling was removed by chemical etching, to improve the hole quality. Anodic oxidation was used for functionalizing the titanium microchannels with TiO2 layers that exhibit convertible wettability behaviour by alternate UV and darkness application. The actuation principle was demonstrated with a prototype microvalve produced.

Gökhan Demir, Ali; Previtali, Barbara; Bestetti, Massimiliano

2011-02-01

86

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

87

Quantitative evaluation of porous media wettability using NMR relaxometry.  

PubMed

We propose a new method to determine wettability indices from NMR relaxometry. The new method uses the sensitivity of low field NMR relaxometry to the fluid distribution in oil-water saturated porous media. The model is based on the existence of a surface relaxivity for both oil and water, allowing the determination of the amount of surface wetted either by oil or by water. The proposed NMR wettability index requires the measurement of relaxation time distribution at four different saturation states. At the irreducible water saturation, we determine the dominant relaxation time of oil in the presence of a small amount of water, and at the oil residual saturation, we determine the dominant relaxation time of water in the presence of a small amount of oil. At 100% water and 100% oil saturation, we determine the surface relaxivity ratio. The interaction of oil with the surface is also evidenced by the comparison of the spin-lattice (T1) and spin-locking (T1rho) relaxation times. The new NMR index agrees with standard wettability measurements based on drainage-imbibition capillary pressure curves (USBM test) in the range [-0.3-1]. PMID:12850740

Fleury, M; Deflandre, F

2003-01-01

88

Pore scale studies of wettability changes in a supercritical CO2-brine-silica system using micromodels  

NASA Astrophysics Data System (ADS)

Capillary pressure is a critical factor controlling CO2 transport, distribution, and equilibrium in geologic carbon sequestration; and it is mainly controlled by brine-CO2 interfacial tension (IFT), wettability, and pore size distribution. Brine-CO2 IFT has been intensively studied by several research groups, covering wide ranges of conditions encountered in geologic carbon storage. However, there is still only a limited amount of published data for wettability in mineral-brine-CO2 systems, especially at the pore scale (< 50 ?m). Reviewing the available literature, most of wettability studies were conducted by measuring contact angles using the captive or sessile drop method on flat substrates, and through core flooding experiments. Contact angle measurements for brine-supercritical CO2 (scCO2) at the pore scale are not available. We studied wettability and wettability alteration at the pore scale, in brine-scCO2-silica systems using engineered micromodels (transparent pore networks) at 8.5 MPa and 318.15 K. We show that the silica surface-brine contact angle increased from initial values near 0 up to 40 to 80 after reaction with scCO2. These measurements indicate that interfacial reactions may change wettability and capillary pressure, especially under more nonequilibrium conditions.

Kim, Y.; Wan, J.; Kneafsey, T. J.; Tokunaga, T. K.

2011-12-01

89

21 CFR 864.6150 - Capillary blood collection tube.  

Code of Federal Regulations, 2010 CFR

...Hematology Devices § 864.6150 Capillary blood collection tube. (a) Identification. A capillary blood collection tube is a plain...small diameter used to collect blood by capillary action. (b) Classification....

2009-04-01

90

21 CFR 864.6150 - Capillary blood collection tube.  

Code of Federal Regulations, 2010 CFR

...Hematology Devices § 864.6150 Capillary blood collection tube. (a) Identification. A capillary blood collection tube is a plain...small diameter used to collect blood by capillary action. (b) Classification....

2010-04-01

91

21 CFR 864.6150 - Capillary blood collection tube.  

Code of Federal Regulations, 2013 CFR

...Hematology Devices § 864.6150 Capillary blood collection tube. (a) Identification. A capillary blood collection tube is a plain...small diameter used to collect blood by capillary action. (b) Classification....

2013-04-01

92

Electrohydrodynamic Enhancement of Extraterrestrial Capillary Pumped Loops for Nuclear Applications  

Microsoft Academic Search

This work examines electrohydrodynamic enhancement of capillary pump loops (CPL) for use in extraterrestrial nuclear applications. A capillary pump uses capillary action through a porous wick to transport heat and mass. The capillary pump is being considered as a method to improve heat transport in extraterrestrial nuclear applications. The work consists of a literature review of electrohydrodynamics, capillary pumped loops

Adam Lipchitz

2010-01-01

93

Water wettability in nanoconfined environment  

NASA Astrophysics Data System (ADS)

Water confined in nanoscale space behaves quite differently from that in the bulk. For example, in biological aquaporins and in carbon nanotubes, the traversing water molecules form a single file configuration. Water would stay in vapor state in extremely hydrophobic narrow nanopores owing to the physicochemical interactions between the water molecules and the surface of the nanopore. A spontaneous wet-dry transition has been identified in both biological and artificial nanopores. The nanopore is either fulfilled with liquid water or completely empty. Based on this mechanism, the wetting and dewetting processes inside nanopores have been further developed into highly efficient nanofluidic gates that can be switched by external stimuli, such as light irradiation, electric potential, temperature, and mechanical pressure. This review briefly covers the recent progress in the special wettability in nanoconfined environment, water transportation through biological or artificial nanochannels, as well as the smart nanofluidic gating system controlled by the water wettability.

Zhou, YaHong; Guo, Wei; Jiang, Lei

2014-05-01

94

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

PubMed

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

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

2008-12-16

95

Electron-induced wettability modification  

SciTech Connect

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

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

2007-07-15

96

Wettability-dependent DNAPL migration in a rough-walled fracture.  

PubMed

The effect of wettability on the migration of dense non-aqueous phase liquids (DNAPLs) through a rough-walled fracture was investigated. The migration characteristics of DNAPL were found to be strongly dependent on the wettability. For a fracture with a hydrophilic surface, DNAPL migrated through larger apertures as disconnected blobs when the groundwater flow regime was linear (Re=1). However, for non hydrophilic surfaces DNAPL did not migrate in the same way as for the hydrophilic surface. The intermediate-wet surface, with a contact angle of approximately 90 degrees , makes gravity pressure dominant over the capillary pressure, resulting in the fastest DNAPL migration. DNAPL was retained on the hydrophobic fracture, where the capillary barrier of larger apertures forced the DNAPL to migrate through the smaller apertures. In the nonlinear flow regime of Re=60, DNAPL generally migrated downward as a result of the inertial pressure of flowing water for all the wettability conditions, but the local downward migration paths were still determined by the capillary pressure, which resulted in the fastest and slowest migration on the hydrophilic and the hydrophobic fractures, respectively. This study implies that the hydrophilic and intermediate-wet surfaces will be favorable for DNAPL and oil recovery. PMID:20110134

Lee, Hang-Bok; Yeo, In Wook; Ji, Sung-Hoon; Lee, Kang-Kun

2010-04-01

97

Auger electron spectroscopy applied to braze wettability  

SciTech Connect

The initial requirement for brazing is for the liquid metal filler alloy to wet the solid metal surfaces. While atomically clean metal surfaces are not necessary for good wettability, excessive oxygen (metal oxide) and/or carbon contaminants will leave non-wettable surfaces. The causes of non-wettable surfaces during brazing have been examined utilizing Auger electron spectroscopy. This surface spectroscopy with a sampling depth of 10 to 20A combined with sputter etching to provide film profiles was used to examine non-wettable specimens. Three different systems were studied. In the first case, carbon was found to segregate from the bulk to the surface of a nickel-copper alloy (Monel) during the braze heating. The formation of a graphitic layer was responsible for the non-wettability. In the second case, an external carbon contaminant was found on the surface of 316 stainless steel and resulted in a non-wettable surface. In the third situation, the non-wettability of 304 stainless steel was caused by a thick oxide film which formed in vacuum during brazing.

Chin, R.L.; Larson, D.T.

1981-01-01

98

Wettability of Aluminum on Alumina  

NASA Astrophysics Data System (ADS)

The wettability of molten aluminum on solid alumina substrate has been investigated by the sessile drop technique in a 10-8 bar vacuum or under argon atmosphere in the temperature range from 1273 K to 1673 K (1000 °C to 1400 °C). It is shown that the reduction of oxide skin on molten aluminum is slow under normal pressures even with ultralow oxygen potential, but it is enhanced in high vacuum. To describe the wetting behavior of the Al-Al2O3 system at lower temperatures, a semiempirical calculation was employed. The calculated contact angle at 973 K (700 °C) is approximately 97 deg, which indicates that aluminum does not wet alumina at aluminum casting temperatures. Thus, a priming height is required for aluminum to infiltrate a filter. Wetting in the Al-Al2O3 system increases with temperature.

Bao, Sarina; Tang, Kai; Kvithyld, Anne; Tangstad, Merete; Engh, Thorvald Abel

2011-12-01

99

Capillary fracturing in granular media  

NASA Astrophysics Data System (ADS)

The invasion of gas into liquid-saturated, deformable porous media occurs in many processes including gas venting, hydrocarbon recovery, and geologic CO2 sequestration. While fracturing during gas invasion has been observed in several studies, the underlying mechanisms and macroscopic patterns remain poorly understood. Here, we experimentally investigate the fracturing mechanism and resulting patterns during the invasion of air into a thin bed of water-saturated glass beads. The control parameters are the air injection rate, the bead size, and the vertical confining stress applied to the top of the bed. We identify three invasion regimes: capillary fingering, viscous fingering, and ``capillary fracturing,'' where capillary forces overcome frictional resistance and induce the opening of fracture-like conduits. We show that the transitions between the regimes are governed by a modified capillary number and a fracturing number. We then extend the experiments to investigate the effect of wettability. Our analysis predicts the emergence of fracturing in fine-grained media under low confining stress, a phenomenon that likely plays a fundamental role in many natural systems.

Szulczewski, Michael; Holtzman, Ran; Trojer, Mathias; Juanes, Ruben

2013-03-01

100

Wettability of azobenzene self-assembled monolayers.  

PubMed

The wettability properties of azobenzene self-assembled monolayers (SAMs), in the trans and cis forms, are investigated herein by classical Molecular Dynamics simulations of validated assembly structures described with a dedicated force field. The two different methodologies used for the calculation of the contact angle, one based on the Young's equation and the other on geometrical models, have provided a consistent description of the SAMs wettability in line with available experimental results. Furthermore, we provide an atomistic description of the first layers of water molecules at the solvent-SAM interface, which rationalizes the wettability difference between the cis- and trans-SAMs. PMID:24673397

Pipolo, Silvio; Corni, Stefano

2014-04-22

101

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

102

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

103

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

104

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

105

Capillary penetration failure of blood suspensions.  

PubMed

Blood suspension fails to penetrate a capillary with radius R less than 50 microm even if the capillary is perfectly wettable. This invasion threshold is attributed to three red blood cells (RBCs) segregation mechanisms--corner deflection at the entrance, the intermediate deformation-induced radial migration and shear-induced diffusion within a packed slug at the meniscus. The shear-induced radial migration for deformable particles endows the blood cells with a higher velocity than the meniscus to form the concentrated slug behind the meniscus. This tightly packed slug has a higher resistance and arrests the flow. Rigid particles and rigidified blood cells result in wetting behavior similar to that seen for homogeneous liquids, with decreased RBC migration towards the capillary centerline and reduction of packing. Corner deflection with a radial drift velocity accelerates the radial migration for small capillaries. However, deformation-induced radial migration is the key mechanism responsible for penetration failure. This sequence of mechanisms is confirmed through videomicroscopy and scaling theories were applied to capture the dependence of the critical capillary radius as a function of RBC concentrations. PMID:15925633

Zhou, Ronghui; Chang, Hsueh-Chia

2005-07-15

106

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

107

Alkyl- and fluoroalkyltrialkoxysilanes for wettability modification  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

108

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

PubMed Central

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

Walczak, Krzysztof Z; Koziol, Krzysztof K K

2011-01-01

109

[Action].  

PubMed

In recent years, the mechanisms related to decision-making in the brain have been proposed and studied. The neural mechanisms involved in the selection of an action prior to its execution are becoming evident, particularly in relation to the frontal lobe. Nevertheless, the fundamental neural mechanisms of movement remain unknown, although it is generally accepted that these actions are controlled by higher-order motor areas in the brain. Movement is the result of a series of timed contractions of various muscle groups; however, elucidating the underlying neural basis of this temporal control would be a challenge in the future. PMID:24748089

Taira, Masato

2014-04-01

110

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

111

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

112

Estimation of Wettability and Wettability Hysteresis Using Solid and Fluid Interfacial Properties  

NASA Astrophysics Data System (ADS)

Wettability, a three phase property quantified by contact angles, is a necessary property for multiphase flow models that is difficult to measure directly in the field and is likely to vary across a single site due to variations in each of the three phases. Furthermore, the soil water content may contribute to wettability hysteresis leading to complex NAPL architecture in the source zone. It is also difficult to accurately replicate field conditions as a method to measure wettability in the lab. However, solid composition and NAPL-aqueous phase interfacial tension can be more easily determined than contact angles and can be done at multiple locations and depths utilizing core samples. A method to estimate the wettability of solid-NAPL-water systems and the likelihood of wettability hysteresis in those systems is demonstrated for a wide variety of solids including silicates, carbonates, and carbonaceous materials. The applicability and limitations of the method for varying NAPL and aqueous phase composition is examined. This method seeks to enhance remediation performance with site data that is readily available.

Sweeney, K.; Ryder, J. L.

2012-12-01

113

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

114

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

115

Chirality-driven wettability switching and mass transfer.  

PubMed

Enantioselective wetting: Regulating the surface wettability of materials through chiral molecules provides new insight into the design of chiral materials. By taking advantage of a reversible conformational transition, smart polymers present an ideal platform for translating weak chiral signals into macroscopic properties of materials, thus resulting in a distinctive wettability switching driven by chirality. PMID:24285641

Qing, Guangyan; Sun, Taolei

2014-01-20

116

Aging effects on wettability and structure of ion implanted silicone  

Microsoft Academic Search

The wettability, structure, and chemical states of ion implanted silicone rubbers were investigated in relation to aging in air and vacuum. H+ He+, C+, N+, O+, Ne+, Na+, N+2, O+2, Ar+ and K+ ion implantations were performed at energies of 100 and 150 keV at room temperature. Wettability was investigated by contact angle measurements, which showed that the contact angle

Suzuki Yoshiaki; Swapp Craig; Kusakabe Masahiro; Iwaki Masaya

1990-01-01

117

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

118

Pool boiling of nanoparticle-modified surface with interlaced wettability.  

PubMed

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

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

2012-01-01

119

Capillary Driven Flows Along Differentially Wetted Interior Corners  

NASA Technical Reports Server (NTRS)

Closed-form analytic solutions useful for the design of capillary flows in a variety of containers possessing interior corners were recently collected and reviewed. Low-g drop tower and aircraft experiments performed at NASA to date show excellent agreement between theory and experiment for perfectly wetting fluids. The analytical expressions are general in terms of contact angle, but do not account for variations in contact angle between the various surfaces within the system. Such conditions may be desirable for capillary containment or to compute the behavior of capillary corner flows in containers consisting of different materials with widely varying wetting characteristics. A simple coordinate rotation is employed to recast the governing system of equations for flows in containers with interior corners with differing contact angles on the faces of the corner. The result is that a large number of capillary driven corner flows may be predicted with only slightly modified geometric functions dependent on corner angle and the two (or more) contact angles of the system. A numerical solution is employed to verify the new problem formulation. The benchmarked computations support the use of the existing theoretical approach to geometries with variable wettability. Simple experiments to confirm the theoretical findings are recommended. Favorable agreement between such experiments and the present theory may argue well for the extension of the analytic results to predict fluid performance in future large length scale capillary fluid systems for spacecraft as well as for small scale capillary systems on Earth.

Golliher, Eric L. (Technical Monitor); Nardin, C. L.; Weislogel, M. M.

2005-01-01

120

Criteria for three-fluid configurations including layers in a pore with nonuniform wettability  

NASA Astrophysics Data System (ADS)

Recently, a considerable effort has been made to determine the precise displacement criteria for three-fluid configurations in pores of angular cross section. These configurations may contain thick conducting fluid layers, such as oil layers residing between gas in the center and water in the corners of the pore. For pores of uniform, but arbitrary, wettability and in the absence of contact angle hysteresis, a precise thermodynamic criterion for the existence of such layers has been established. In this paper we derive similar criteria for layers in pores of nonuniform wettability, where additional and more complicated layer configurations arise. The criteria for formation and removal of layers are consistent with the capillary entry conditions for the accompanying three-phase bulk displacements, which is essential for accurate pore-scale modeling of three-phase flow. We consider the particular case of three-phase gas invasion in a star-shaped pore with a specific choice of interfacial tensions and contact angles. For this case all possible fluid configurations arise, but only if the water-wet surface in the pore corners is small.

van Dijke, M. I. J.; Piri, M.; Helland, J. O.; Sorbie, K. S.; Blunt, M. J.; SkjæVeland, S. M.

2007-12-01

121

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

PubMed Central

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

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

2013-01-01

122

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

123

Capillary trapping under mixed-wet conditions: laboratory observations  

NASA Astrophysics Data System (ADS)

As a wetting phase displaces a non-wetting phase in a porous medium, a portion of the latter becomes immobilized by capillary forces as discontinuous pore-scale ganglia. This phenomenon, known as capillary trapping, hinders the extraction of non-aqueous contaminants from groundwater and oil from geological reservoirs. Here, we consider the impact of wettability on capillary trapping. In uniformly water-wet media, it is well established that residual non-wetting phase saturation increases monotonically with its initial saturation. In contrast, little is understood about mixed-wet media, in which parts of the pore surface are oil-wet while the rest is water-wet. We present laboratory measurements of residual oil saturation in a limestone in its original, water-wet state and under mixed-wet conditions established systematically using organic acid. The data show that, in contrast to water-wet systems, waterflood residual in mixed-wet systems exhibits three distinct regimes as initial saturation is increased. In particular, there is an intermediate regime in which residual saturation decreases as initial saturation increases. These observations may have important implications for enhanced oil recovery, groundwater remediation, and injection schemes at carbon storage sites where contact with injected CO_2 alters the wettability of the grain surface.

Tanino, Y.; Blunt, M. J.

2012-12-01

124

Wettability Switching Techniques on Superhydrophobic Surfaces  

NASA Astrophysics Data System (ADS)

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.

Verplanck, Nicolas; Coffinier, Yannick; Thomy, Vincent; Boukherroub, Rabah

2007-12-01

125

Capillary sample (image)  

MedlinePLUS

A capillary sample of blood is obtained by pricking the skin's surface to obtain a drop or several drops ... blood for laboratory testing. The usual location of capillary blood sampling is the skin of the finger ...

126

Measurement of surface tension and viscosity by open capillary techniques  

DOEpatents

An open-channel capillary is provided, having preferably a v-shaped groove in a flat wettable surface. The groove has timing marks and a source marker in which the specimen to be tested is deposited. The time of passage between the timing marks is recorded, and the ratio of surface tension .gamma. to viscosity .mu. is determined from the equation given below: ##EQU1## where h.sub.0 is the groove depth, .alpha. is the groove angle, .theta. is the liquid/solid contact angle, and t is the flow time. It has been shown by the

Rye,Robert R. (Albuquerque, NM), Yost,Frederick G. (Cedar Crest, NM)

1998-01-01

127

Surfactant Loss: Effects of Temperature, Salinity, and Wettability.  

National Technical Information Service (NTIS)

Adsorption of sodium dodecylsulfate, Triton X-100, decyltrimethylammonium bromide surfactants onto silica gel and Berea sandstone mineral surfaces has been studied as a function of temperature, solution salt concentration, and mineral surface wettability....

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

1989-01-01

128

Wettability and spreading kinetics of liquid aluminium on boron nitride  

Microsoft Academic Search

The wettability and spreading kinetics of liquid AI on CVD-BN were investigated by the sessile drop method in a vacuum of\\u000a about 1.110?3 Pa at 1070 to 1430 K. The wettability on the Al-BN system was different from that of the Al-SiC system reported in the literature.\\u000a The wetting angle of Al-BN linearly decreased with an increase of temperature in

X. M. Xue; J. T. Wang; M. X. Quan

1991-01-01

129

Leaf wettability decreases along an extreme altitudinal gradient  

Microsoft Academic Search

The duration and amount of water captured on leaves and its functional significance is highly varied. Leaf surface wettability\\u000a influences water absorption, gas exchange, pathogen infection, nutrient leaching, contamination by pollutants, self-cleaning\\u000a properties and in freezing environments the probability of extrinsic ice nucleation. To test the impact of environment on\\u000a the development of leaf wettability, this functional trait was measured

Biva Aryal; Gilbert Neuner

2010-01-01

130

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

131

Characterization of the Capillary Properties of Gas Diffusion Media  

NASA Astrophysics Data System (ADS)

The present generation of membrane materials used in polymer electrolyte membrane fuel cells (PEMFCs) requires high humidity to maintain sufficient proton conductivity. Mass transport through the porous electrodes, however, is most effective in dry conditions since the presence of liquid water in the pores reduces effective oxygen diffusivity to the catalytic sites. Management of these competing requirements is further complicated by the production of water inside the cell as a by-product of the cathode reaction. Maximizing fuel cell power density therefore requires effective water management techniques to prevent excessive liquid water from accumulating in the porous electrode components. Liquid water distribution and flow in the cathode gas diffusion media (GDM) of an operating PEMFC is critically affected by capillary forces. Perhaps the most widely employed technique for improving water management is to impregnate the fibrous GDM with a polymer, such as poly-tetra-fluoro-ethylene (PTFE), to coat the carbon fibers and thereby render the GDM more hydrophobic. It is thus important to understand the relationship between wettability and capillary properties of native (i.e., untreated) or PTFE-treated GDMs on the one hand and the relationship between GDM capillary properties and fuel cell performance on the other hand. Until recently, however, few experimental techniques were available to measure the capillary properties of GDMs. This chapter discusses the present understanding of the capillary properties of GDM-water-air systems and provides a critical analysis of reported experimental techniques that have recently contributed to this understanding.

Gostick, Jeffrey T.; Ioannidis, Marios A.; Fowler, Michael W.; Pritzker, Mark D.

132

Rapid separation of nucleosides by capillary electrochromatography with a methacrylate-based monolithic stationary phase  

Microsoft Academic Search

Summary  Separation of nucleosides by capillary electrochromatography with a methacrylate-based monolithic column is described. Because\\u000a the nucleosides are relatively hydrophilic compounds, chromatographic parition is very weak on non-polar stationary phases.\\u000a A small quantity of organic modifier is usually required to increase their retention factars but, because the wettability\\u000a of the stationary phase by the mobile phase is rather poor, bubble formation

Guichen Ping; Weibing Zhang; Lihua Zhang; P. Schmitt-Kopplin; Yukui Zhang; A. Kettrup

2003-01-01

133

PWB solder wettability after simulated storage  

SciTech Connect

A new solderability test method has been developed at Sandia National Laboratories that simulates the capillary flow physics of solders on circuit board surfaces. The solderability test geometry was incorporated on a circuit board prototype that was developed for a National Center for Manufacturing Sciences (NCMS) program. The work was conducted under a cooperative research and development agreement between Sandia National Laboratories, NCMS, and several PWB fabricators (AT&T, IBM, Texas Instruments, United Technologies/Hamilton Standard and Hughes Aircraft) to advance PWB interconnect technology. The test was used to investigate the effects of environmental prestressing on the solderability of printed wiring board (PWB) copper finishes. Aging was performed in a controlled chamber representing a typical indoor industrial environment. Solderability testing on as-fabricated and exposed copper samples was performed with the Sn-Pb eutectic solder at four different reflow temperatures (215, 230, 245 and 260{degrees}C). Rosin mildly activated (RMA), low solids (LS), and citric acid-based (CA) fluxes were included in the evaluation. Under baseline conditions, capillary flow was minimal at the lowest temperatures with all fluxes. Wetting increased with temperature at both baseline and prestressing conditions. Poor wetting, however, was observed at all temperatures with the LS flux. Capillary flow is effectively restored with the CA flux.

Hernandez, C.L.; Hosking, F.M.

1996-03-01

134

Water Tank with Capillary Air/Liquid Separation  

NASA Technical Reports Server (NTRS)

A bladderless water tank (see figure) has been developed that contains capillary devices that allow it to be filled and emptied, as needed, in microgravity. When filled with water, the tank shields human occupants of a spacecraft against cosmic radiation. A membrane that is permeable by air but is hydrophobic (neither wettable nor permeable by liquid water) covers one inside surface of the tank. Grooves between the surface and the membrane allow air to flow through vent holes in the surface as the tank is filled or drained. A margin of wettable surface surrounds the edges of the membrane, and all the other inside tank surfaces are also wettable. A fill/drain port is located in one corner of the tank and is covered with a hydrophilic membrane. As filling begins, water runs from the hydrophilic membrane into the corner fillets of the tank walls. Continued filling in the absence of gravity will result in a single contiguous air bubble that will be vented through the hydrophobic membrane. The bubble will be reduced in size until it becomes spherical and smaller than the tank thickness. Draining the tank reverses the process. Air is introduced through the hydrophobic membrane, and liquid continuity is maintained with the fill/drain port through the corner fillets. Even after the tank is emptied, as long as the suction pressure on the hydrophilic membrane does not exceed its bubble point, no air will be drawn into the liquid line.

Ungar, Eugene K.; Smith, Frederick; Edeen, Gregg; Almlie, Jay C.

2010-01-01

135

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

136

Controlling the wettability of hierarchically structured thermoplastics.  

PubMed

Surfaces play an important role in defining the properties of materials, controlling wetting, adsorption, or desorption of biomolecules, and sealing/bonding of different materials. We have combined microscale features with plasma-etched nanoscale roughness and chemical modification to tailor the wettability of the substrates. Cyclic olefin polymers and copolymers (COPs/COCs) were processed to make a range of surfaces with controlled superhydrophobic or -hydrophilic properties. The hydrophobic properties of the polymers were increased by the introduction of microstructures of varying geometry and spacing through hot embossing. The COC/COP substrates were functionalized by plasma activation in O(2), CF(4), and a mixture of both gases. The plasma etching introduces nanoscale roughness and also chemically modifies the surface, creating either highly hydrophilic or highly hydrophobic (contact angle >150°) surfaces depending on the gas mixture. The influence of geometry and chemistries was characterized by atomic force microscopy, contact angle measurements, and X-ray photoelectron spectroscopy. Measurements of the contact angle and contact angle hysteresis demonstrated long-term stability of the superhydrophobic/superhydrophilic characteristics (>6 months). PMID:22043942

Cortese, Barbara; Morgan, Hywel

2012-01-10

137

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

138

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

139

Uptake of water droplets by nonwetting capillaries  

Microsoft Academic Search

We present direct experimental evidence that water droplets can spontaneously penetrate non-wetting capillaries, driven by the action of Laplace pressure due to high droplet curvature. Using high-speed optical imaging, microcapillaries of radius 50 to 150 micron, and water microdroplets of average radius between 100 and 1900 micron, we demonstrate that there is a critical droplet radius below which water droplets

Geoff R. Willmott; Chiara Neto; Shaun C. Hendy

2010-01-01

140

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

141

Controlled swapping of nanocomposite surface wettability by multilayer photopolymerization.  

PubMed

Single-layered photopolymerized nanocomposite films of polystyrene and TiO(2) nanorods change their wetting characteristics from hydrophobic to hydrophilic when deposited on substrates with decreasing hydrophilicity. Interestingly, the addition of a second photopolymerized layer causes a swapping in the wettability, so that the final samples result converted from hydrophobic to hydrophilic or vice versa. The wettability characteristics continue to be swapped as the number of photopolymerized layers increases. In fact, odd-layered samples show the same wetting behavior as single-layered ones, while even-layered samples have the same surface characteristics as double-layered ones. Analytical surface studies demonstrate that all samples, independently of the number of layers, have similar low roughness, and that the wettability swap is due to the different concentration of the nanocomposites constituents on the samples surface. Particularly, the different interactions between the hydrophilic TiO(2) nanorods and the underlying layer lead to different amounts of nanorods exposed on the nanocomposites surface. Moreover, due to the unique property of TiO(2) to reversibly increase its wettability upon UV irradiation and subsequent storage, the wetting characteristics of the multilayered nanocomposites can be tuned in a reversible manner. In this way, a combination of substrate, number of photopolymerized layers, and external UV light stimulus can be used in order to precisely control the surface wettability properties of nanocomposite films, opening the way to a vast number of potential applications in microfluidics, protein assays, and cell growth. PMID:21635015

Villafiorita-Monteleone, Francesca; Canale, Claudio; Caputo, Gianvito; Cozzoli, P Davide; Cingolani, Roberto; Fragouli, Despina; Athanassiou, Athanassia

2011-07-01

142

Control over wettability via surface modification of porous gradients  

NASA Astrophysics Data System (ADS)

The control over surface wettability is of concern for a number of important applications including chromatography, microfluidics, biomaterials, low-fouling coatings and sensing devices. Here, we report the ability to tailor wettability across a surface using lateral porous silicon (pSi) gradients. Lateral gradients made by anodisation of silicon using an asymmetric electrode configuration showed a lateral distribution of pore sizes, which decreased with increasing distance from the electrode. Pore sizes were characterised using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Pore diameters ranged from micrometres down to less than 10 nanometres. Chemical surface modification of the pSi gradients was employed in order to produce gradients with different wetting or non-wetting properties. Surface modifications were achieved via silanisation of oxidised pSi surfaces introducing functionalities including polyethylene glycol, terminal amine and fluorinated hydrocarbon chains. Surface modifications were characterised using infrared spectroscopy. Sessile drop water contact angle measurements were used to probe the wettability in regions of different pore size across the gradient. For the fluorinated gradients, a comparison of equilibrium and dynamic contact angle measurement was undertaken. The fluorinated surface chemistry produced gradients with wettabilities ranging from hydrophobic to near super-hydrophobic whereas pSi gradients functionalised with polyethylene glycol showed graded hydrophilicity. In all cases investigated here, changes in pore size across the gradient had a significant effect on wettability.

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

2007-12-01

143

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

144

The tunable wettability in multistimuli-responsive smart graphene surfaces  

NASA Astrophysics Data System (ADS)

The tunable wettability of smart graphene films onto stainless steel substrates with a multi-response to different environmental stimuli has been investigated including light irradiation, pH, electric field, and annealing temperature. Conductive graphene film exhibited the controllable transition from water-repellent to water-loving characteristic in response to different environment fields, which primarily resulted from the morpho-chemically synergistic effect as well as the restoration of electronic stucture. Based on the fundamental theories of wettability, mechanisms in switching from hydrophobicity to hydrophilicity for smart graphene surface including thermal chemistry, electrostatic, photo-induced surface chemistry, solvent, and pH methods were presented.

Wan, Shanhong; Pu, Jibin; Zhang, Xiaoqian; Wang, Liping; Xue, Qunji

2013-01-01

145

Wettability of naturally aged silicone and EPDM composite insulators  

Microsoft Academic Search

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

S. M. Gubanski; A. E. Vlastos

1990-01-01

146

Surface wettability of atmospheric dielectric barrier discharge processed Armos fibers  

Microsoft Academic Search

Wettability of Armos fibers has been investigated after exposed to dielectric barrier discharge (DBD) plasma, which was performed at atmospheric pressure in air while varying the sample treatment time between 9 and 27s. Contact angles and surface free energy of the original and plasma-treated fibers were measured with dynamic contact angle analysis (DCAA) to reveal the correlation between the fiber

Caixia Jia; Ping Chen; Qian Wang; Bin Li; Mingxin Chen

2011-01-01

147

Wettability of Nafion and Nafion/Vulcan carbon composite films.  

PubMed

The wettability of the Pt/carbon/Nafion catalyst layer in proton exchange membrane fuel cells is critical to their performance and durability, especially the cathode, as water is needed for the transport of protons to the active sites and is also involved in deleterious Pt nanoparticle dissolution and carbon corrosion. Therefore, the focus of this work has been on the first-time use of the water droplet impacting method to determine the wettability of 100% Nafion films, as a benchmark, and then of Vulcan carbon (VC)/Nafion composite films, both deposited by spin-coating in the Pt-free state. Pure Nafion films, shown by SEM analysis to have a nanochanneled structure, are initially hydrophobic but become hydrophilic as the water droplet spreads, likely due to reorientation of the sulfonic acid groups toward water. The wettability of VC/Nafion composite films depends significantly on the VC/Nafion mass ratios, even though Nafion is believed to be preferentially oriented (sulfonate groups toward VC) in all cases. At low VC contents, a significant water droplet contact angle hysteresis is seen, similar to pure Nafion films, while at higher VC contents (>30%), the films become hydrophobic, also exhibiting superhydrophobicity, with surface roughness playing a significant role. At >80% VC, the surfaces become wettable again as there is insufficient Nafion loading present to fully cover the carbon surface, allowing the calculation of the Nafion:carbon ratio required for a full coverage of carbon by Nafion. PMID:22475507

Li, Xiaoan; Feng, Fangxia; Zhang, Ke; Ye, Siyu; Kwok, Daniel Y; Birss, Viola

2012-04-24

148

Wettability of Freon hydrates in crude oil\\/brine emulsions  

Microsoft Academic Search

The surface energy of petroleum hydrates is believed to be a key parameter with regard to hydrate morphology and plugging tendency in petroleum production. As of today, the surface energy of natural gas hydrates is unknown, but will depend on the fluids in which they grow. In this work, the wettability of Freon hydrates is evaluated from their behavior in

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

2005-01-01

149

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

150

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

SciTech Connect

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

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

1999-03-01

151

Brine film thicknesses on mica surfaces under geologic CO2 sequestration conditions and controlled capillary pressures  

NASA Astrophysics Data System (ADS)

Brine films remaining on mineral surfaces in deep reservoirs during CO2 sequestration are expected to influence multiphase flow, diffusion, and reactions, but little is known about their behavior. Using synchrotron X-ray fluorescence (XRF), we measured thicknesses of KCsI2 brine films on two difference roughness mica surfaces under conditions representative of geological CO2 sequestration (7.8 MPa and 40°C) to understand the influences of mineral surface roughness and capillary potential. Brine thicknesses measured on the Mica 1 (smooth) and Mica 2 (rough) mica surfaces ranged from 23 to 8 nm and 491 to 412 nm, respectively, over the small range of tested capillary potentials (0.18-3.7 kPa). Within these potentials, brine film thicknesses on mica were governed by surface roughness and only weakly influenced by capillary potentials. In comparing drainage and rewetting isotherms, some film thickness hysteresis was observed, possibly indicative of changes in mica wettability.

Kim, Tae Wook; Tokunaga, Tetsu K.; Bargar, John R.; Latimer, Matthew J.; Webb, Samuel M.

2013-08-01

152

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 121°C. 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 105°C. 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

153

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

154

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

155

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

156

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

157

Nasal Lobular Capillary Hemangioma  

PubMed Central

Nasal lobular capillary hemangioma is a rare benign tumor of the paranasal sinuses. This lesion is believed to grow rapidly in size over time. The exact etiopathogenesis is still a dilemma. We discuss a case of nasal lobular capillary hemangioma presenting with a history of epistaxis. Contrast enhanced computed tomography of paranasal sinuses revealed an intensely enhancing soft-tissue mass in the left nasal cavity and left middle and inferior meati with no obvious bony remodeling or destruction. We present imaging and pathologic features of nasal lobular capillary hemangioma and differentiate it from other entities like nasal angiofibroma.

Patil, Prashant; Singla, Saurabh; Mane, Ranoji; Jagdeesh, K. S.

2013-01-01

158

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

159

Displaced capillary dies  

DOEpatents

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

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

1982-01-01

160

Displaced capillary dies  

DOEpatents

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

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

1984-01-01

161

Liquid capillary scintillation detectors  

SciTech Connect

The authors have been developing liquid-in-capillary detectors for tracking applications in high energy physics experiments. The detectors consist of glass capillaries of low refractive index filled with liquids of sufficiently high refractive index to produce an efficient waveguides. This paper describes recent work in which scintillating core liquids were prepared from the solvent 1-phenylnaphthalene and single solutes of selected fluorescent dyes.

Puseljic, D.; Baumbaugh, B.; Ditmire, T.; Kennedy, C.; Ruchti, R.; Ryan, J. (Notre Dame Univ., IN (USA). Dept. of Physics); Baumbaugh, A.; Knickerbocker, K. (Collimated Holes, Inc., Campbell, CA (USA)); Ellis, J.; Mead, R.; Swanson, D. (Collimated Holes, Inc., Campbell, CA (USA))

1990-04-01

162

Numerical study of drop motion on a surface with stepwise wettability gradient and contact angle hysteresis  

NASA Astrophysics Data System (ADS)

In this work, the motion of a two-dimensional drop on a surface with stepwise wettability gradient (WG) is studied numerically by a hybrid lattice-Boltzmann finite-difference method. We incorporate the geometric wetting boundary condition that allows accurate implementation of a contact angle hysteresis (CAH) model. The method is first validated through a series of tests that check different constituents of the numerical model. Then, simulations of a drop on a wall with given stepwise WG are performed under different conditions. The effects of the Reynolds number, the viscosity ratio, the WG, as well as the CAH on the drop motion are investigated in detail. It was discovered that the shape of the drop in steady motion may be fitted by two arcs that give two apparent contact angles, which are related to the respective contact line velocities and the relevant contact angles (that specify the WG and CAH) through the relation derived by Cox ["The dynamics of the spreading of liquids on a solid surface. Part 1. viscous flow," J. Fluid Mech. 168, 169-194 (1986)] if the slip length in simulation is defined according to Yue et al. ["Sharp-interface limit of the Cahn-Hilliard model for moving contact lines," J. Fluid Mech. 645, 279-294 (2010)]. It was also found that the steady capillary number of the drop is significantly affected by the viscosity ratio, the magnitudes of the WG, and the CAH, whereas it almost shows no dependence on the Reynolds number.

Huang, Jun-Jie; Huang, Haibo; Wang, Xinzhu

2014-06-01

163

Tunable photonic crystal based on capillary attraction and repulsion.  

PubMed

A tunable photonic crystal (PhC) based on the capillary action of liquid is demonstrated in this work. The porous silicon-based photonic crystal (PSiPhC) features periodic porosity and is fabricated by electrochemical etching on 6" silicon wafer followed by hydrophobic modification on the silicon surface. The capillary action is achieved by varying the mixture ratio of liquids with high and low surface tension, yielding either capillary attraction or capillary repulsion in the nanoscale voids of the PSiPhC. By delivering the liquid mixture into and out of the voids of the PSiPhC, the reflective color of the PSiPhC can be dynamically tuned. PMID:20940984

Chan, Chia-Tsung; Yeh, J Andrew

2010-09-27

164

Uptake of water droplets by nonwetting capillaries  

Microsoft Academic Search

We present direct experimental evidence that water droplets can spontaneously\\u000apenetrate non-wetting capillaries, driven by the action of Laplace pressure due\\u000ato high droplet curvature. Using high-speed optical imaging, microcapillaries\\u000aof radius 50 to 150 micron, and water microdroplets of average radius between\\u000a100 and 1900 micron, we demonstrate that there is a critical droplet radius\\u000abelow which water droplets

Geoff R. Willmott; Chiara Neto; Shaun C. Hendy

2010-01-01

165

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

166

Wettability changes of TiO2 nanotube surfaces  

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

167

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.

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

2013-01-01

168

Bio-inspired electrospun micro/nanofibers with special wettability.  

PubMed

Inspired by the extreme wetting states displayed by the natural materials, various techniques have been widely investigated to fabricate superhydrophobic and superhydrophilic surfaces. Electrospinning has gained huge amount of interest as fibers with suitable combination of surface chemistry and surface roughness can be easily obtained. This study provides a comprehensive overview of the progress that has been made on electrospun fibers that display superhydrophobicity, superhydrophilicity or a combination of both. The article discusses various modification techniques that can be implemented to obtain fibers with surface heterogeneity for improving its hydrophobicity or hydrophilicity. Both nanometer size of the fibers and secondary nanoscale structures ensure that the fibers have suitable surface topography to exhibit extreme wetting states. Additionally, for the first time, we critically review and identify the role of intrinsic structures such as crystallinity and chain orientation on the wettability of the fibers. We highlight some new emerging application areas that are being explored using superhydrophobic and superhydrophilic fibers. Further, methods for fabricating smart materials with special wettability are also discussed. Such fibers with special wettability show tremendous promise for water harvesting, unidirectional water collection and oil-water filtration applications. PMID:24757946

Baji, Avinash; Abtahi, Mojtaba; Ramakrishna, Seeram

2014-07-01

169

Wettability of Freon hydrates in crude oil/brine emulsions.  

PubMed

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

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

2005-07-01

170

Layer thickness of hydrophobin films leads to oscillation in wettability.  

PubMed

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

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

2012-05-01

171

Patterned wettability of oil and water in porous media.  

PubMed

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

Kumar, Munish; Fogden, Andrew

2010-03-16

172

Surface modification of polystyrene for improving wettability by ion implantation  

NASA Astrophysics Data System (ADS)

A study has been made on the wettability, structure, and chemical states of ion implanted polystyrene. Ne + and Na + ion implantations were performed at energies of 50, 100, and 150 keV at room temperature. The fluences ranged from 1 × 10 14 to 1 × 10 17 ions/cm 2. Wettability was estimated by means of a sessile drop method using water. The results showed that the contact angle of water for Na + implanted polystyrene decreased from 87° to zero, as the fluences increased at energies of 50 and 100 keV. The contact angle for Na + implanted polystyrene did not change under ambient room conditions even if the time elapsed. However, the contact angle for Ne + ion implanted specimen slightly decreased to 65°. Results of X-ray photoelectron spectroscopy showed that an increase in the Na content in the surface was observed with decreasing implantation energy. It is concluded that permanent improvement in wettability is caused by doping effects rather than radiation effects induced by Na + ion implantation.

Suzuki, Yoshiaki; Kusakabe, Masahiro; Iwaki, Masaya

1993-06-01

173

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

174

Wettability estimation of low-permeability, siliceous shale using surface forces  

Microsoft Academic Search

This work evaluates shale\\/oil wettability and wettability alteration by solutions whose pH ranges from 3 to 12. The reservoir rocks are siliceous shale that are fractured and low permeability oil-bearing rocks. Wettability alteration is evaluated in terms of estimated thin-film stability, contact angle, and fines migration. Previously, we presented core-scale spontaneous countercurrent imbibition and forced displacement results for the crude

Satoru Takahashi; Anthony R. Kovscek

2010-01-01

175

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

SciTech Connect

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

Sharma, Mukul M.; Hirasaki, George J.

2002-01-28

176

Stability of capillary surfaces  

Microsoft Academic Search

An extensive data set quantifying the stability limits of capillary surfaces for a wide range of fluid properties, container geometry, and input disturbance and orientation does not currently exist. To begin to provide such a data set an experimental apparatus has been designed for which the dynamics and stability of fluid interfaces will be investigated. The apparatus consists primarily of

Mark Weislogel

1991-01-01

177

Role of geometry and amphiphilicity on capillary-induced interactions between anisotropic Janus particles.  

PubMed

We study the capillary interactions between ellipsoidal Janus particles adsorbed at flat liquid-fluid interfaces. In contrast to spherical particles, Janus ellipsoids with a large aspect ratio or a small difference in the wettability of the two regions tend to tilt at equilibrium. The interface deforms around ellipsoids with tilted orientations and thus results in energetic interactions between neighboring particles. We quantify these interactions through evaluation of capillary energy variation as a function of the spacing and angle between the particles. The complex meniscus shape results in a pair interaction potential which cannot be expressed in terms of capillary quadrupoles as in homogeneous ellipsoids. Moreover, Janus ellipsoids in contact exhibit a larger capillary force at side-by-side alignment compared to the tip-to-tip configuration, while these two are of comparable magnitude for their homogeneous counterparts. We evaluate the role of particles aspect ratio and the degree of amphiphilicity on the interparticle force and the capillary torque. The energy landscapes enable prediction of micromechanics of particle chains, which has implications in predicting the interfacial rheology of such particles at fluid interfaces. PMID:24205863

Rezvantalab, Hossein; Shojaei-Zadeh, Shahab

2013-12-01

178

Carbon nanotube patterning with capillary micromolding of catalyst.  

PubMed

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

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

2007-11-01

179

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

180

Displacement of a liquid in a capillary tube subject to microgravitational effects  

Microsoft Academic Search

Liquid displacement in a capillary tube subject to very small, but non-null gravitational effects is investigated theoretically. An equation of motion for the liquid is established by taking into account the capillary action, friction between the liquid and the tube's walls, shape of the meniscus, variations in pressure through the tube, inertia of the liquid, and the speed of the

F. Feuillebois; A. Lasek

1977-01-01

181

Theory of Edge Capillary-Gravity Waves  

NASA Astrophysics Data System (ADS)

We consider a body of fluid in equilibrium in a gravitational field and having a free surface and a plane-sloping beach with a straight coastline. If, under the action of some external disturbances, the surface is moved its equilibrium position, motion will occur in the fluid. This motion will be propagated along the coast in the form of waves, which are driven under the action of gravity and surface tension forces. We call these waves edge capillary-gravity waves, if their amplitude decays exponentially with distance from the coast. The fluid is considered inviscid, irrotational and incompressible. Under these conditions the velocity potencial satisfies the Laplace's equation everywhere in the fluid. The boundary conditions are such that the normal velocity at the bottom is zero and on the free surface in the presence of surface tension the linearized kinematic and dynamic boundary conditions are satisfied. The main difficulty for solution of this problem is that the variables are not separated. We present explicit solutions for all modes of the edge capillary-gravity waves and the dispersion equation. Capillary forces affect markedly the edge gravity waves profiles over the high frequency range. The peaks and lows have become larger as compared to pure edge gravity waves, dependence on the radial coordinate becomes more complicated, and a number of zeros of a mode might not coincide with the number of the mode. When ignoring capillary forces, our results are in complete agreement with the classic results of Ursell (1952) for the edge gravity waves on a sloping beach.

Muzylev, S. V.; Bulgakov, S. N.

2004-12-01

182

Wettability of elastomeric impression materials and voids in gypsum casts.  

PubMed

Numerous factors are involved in making an accurate void-free dental artificial stone cast or die. The relationship of the wettability of an elastomeric impression material and its interaction with the gypsum slurry is an important factor. This study examined the relative "pourability" of several impression materials by counting the number of resultant voids in artificial stone casts containing 48 point angles. Those elastomers that exhibited the lowest contact angle with water produced artificial stone casts with the fewest voids. Surfactants applied to the impression material significantly reduced the number of voids in artificial stone casts, as did modified elastomers designated by the manufacturer as hydrophilic. PMID:1774689

Cullen, D R; Mikesell, J W; Sandrik, J L

1991-08-01

183

Tailoring the wettability of nanocrystalline TiO 2 films  

NASA Astrophysics Data System (ADS)

The water contact angle (WCA) of nanocrystalline TiO 2 films was adjusted by fluoroalkylsilane (FAS) modification and photocatalytic lithography. FAS modification made the surface hydrophobic with the WCA up to ˜156°, while ultraviolet (UV) irradiation changed surface to hydrophilic with the WCA down to ˜0°. Both the hydrophobicity and hydrophilicity were enhanced by surface roughness. The wettability can be tailored by varying the concentration of FAS solution and soaking time, as well as the UV light intensity and irradiation time. Additionally, with the help of photomasks, hydrophobic-hydrophilic micropatterns can be fabricated and manifested via area-selective deposition of polystyrene particles.

Liang, Qiyu; Chen, Yan; Fan, Yuzun; Hu, Yong; Wu, Yuedong; Zhao, Ziqiang; Meng, Qingbo

2012-01-01

184

The wettability of selected organic soils in Poland  

NASA Astrophysics Data System (ADS)

The wettability was measured in the laboratory by means of two methods: Water Drop Penetration Time (WDPT) test and Thin Column Wicking (TCW) method. WDPT is fast and simple method and was used to investigate potential water repellency of analyzed samples. TCW is an indirect method and was used to determine contact angles and surface free energy components. The measurement was performed in horizontal teflon chambers for thin-layer chromatography, adapted for tubes 10 cm long. The experiment was carried out on muck soils (samples were taken from two levels of soil profile: 0-20 cm and 20-40 cm) and peat soils. There were two types of peats: low-moor peats and high moor peats. Samples of low-moor peats were taken from level 25-75 cm (alder peat) and 75-125cm (sedge peat) and 25-75 cm (peloid peat). Samples of high moor peats from level 25-175 cm (sphagnum peat) and 175-225 cm (sphagnum peat with Eriophorum). There was found no variability in persistence of potential water repellency but there were differences in values of contact angles of individual soil samples. Both muck and peat samples are extremely water repellent soils. Water droplets persisted on the surface of soils for more than 24 hours. Contact angles and surface free energy components for all samples were differentiated. Ranges of water contact angles for organic soils are from 27,54o to 96,50o. The highest values of contact angles were for sphagnum peats, and the lowest for muck soil from 20-40 cm level. It means, that there are differences in wettability between these samples. Muck soil is the best wettable and sphagnum peats is the worst wettable soil. If the content of organic compounds in the soil exceeds 40% (like in peats), the tested material displays only dispersion-type interactions. Therefore for peat soils, the technique of thin column wicking could only be used to determine the dispersive component γiLW. For muck soils it was also determined electron-acceptor (Lewis acid) γ+ and electron-donor (Lewis base) γ- surface free energy components. The authors gratefully acknowledge the Ministry of Science and Higher Education for financial support of this work (grant No. N N310 149335).

Ca?ka, A.; Hajnos, M.

2009-04-01

185

Properties of soil organic matter and aqueous extracts of actually water repellent and wettable soil samples  

Microsoft Academic Search

The occurrence of water repellent spots can inhibit a homogeneous wetting progress in soil. Although the wettability is an important factor for sorption and transport processes, the knowledge about the reasons for water repellent behavior and its effects on other soil properties is still insufficient. In this study, water repellent and wettable soil samples from two urban locations were compared.

Julia Hurraß; Gabriele E. Schaumann

2006-01-01

186

Time-related wettability characteristic of acrylic resin surfaces treated by glow discharge  

Microsoft Academic Search

Statement Of Problem. Adhesion and cohesion have important roles in denture retention, and attempts have been made to improve the wettability of the acrylic resin material by surface treatments. Purpose. This study examined the initial and subsequent wettability of an acrylic resin denture base material treated under air or argon plasma atmosphere before and after exposure to air or distilled

Nehir Özden; Funda Akaltan; Sefik Suzer; Guneri Akovali

1999-01-01

187

A comparative study of the wettability of steel, carbon, and polyethylene fibers by water  

Microsoft Academic Search

The wettability of fibers by water was found to increase in this order: polyethylene fiber, steel fiber, and carbon fiber. The order applies whether the fibers were surface-treated or not. Treatment with ozone was effective for improving the wettability of carbon and steel fibers. Treatment with acetone was effective for steel and polyethylene fibers. Treatments with HCl and NaOH were

W. Lu; X. Fu; D. D. L. Chung

1998-01-01

188

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

Microsoft Academic Search

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

Li-Chong Xu; Christopher A. Siedlecki

2007-01-01

189

Diode laser modification of ceramic material surface properties for improved wettability and adhesion  

Microsoft Academic Search

To date, very little work has been published with regard specifically to the use of lasers for modifying the surface properties of materials in order to improve their wettability and adhesion characteristics. Using a 60 W high power diode laser (HPDL) the effects of HPDL radiation on the wettability and adhesion characteristics of certain ceramic materials have been determined. It

J. Lawrence; L. Li; J. T. Spencer

1999-01-01

190

Wettability Alteration of Low-permeable Carbonate Reservoir Rocks in Presence of Mixed Ionic Surfactants  

Microsoft Academic Search

Altering the wettability of the carbonate reservoir rocks from oil-wet to water-wet has figured prominently as one of the enhanced oil recovery methods in recent years. The authors measured the effect of different ionic surfactants on the wettability alteration of the rock, saturated with crude oil, and the consequent improvement in oil production was investigated by spontaneous imbibitions of solutions

H. Vatanparast; A. H. Alizadeh; A. Bahramian; H. Bazdar

2011-01-01

191

Turbulence of Capillary Waves  

NASA Astrophysics Data System (ADS)

A numerical model for direct simulation of the surface of ideal fluid based on the expansion of the Hamiltonian of the surface up to terms of fourth order is developed. For the case of capillary wave we observe the formation of powerlike spectrum of spatial elevations close to one predicted by weak-turbulent theory Ik~=k-19/4, which previously was not confirmed either experimentally or numerically.

Pushkarev, A. N.; Zakharov, V. E.

1996-04-01

192

Designer-Wet Micromodels for Studying Potential Changes in Wettability during Microbial Enhanced Oil Recovery  

NASA Astrophysics Data System (ADS)

Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary recovery of oil. Some bacteria can facilitate the mobilization of oil through the production of amphiphilic compounds called biosurfactants that reduce the interfacial tension (IFT) between immiscible phases. Additionally, most bacteria have an inclination to colonize surfaces and form biofilm, which can change a reservoir's wetting properties or clog preferential flow paths. Herein, we aim to understand changes in wettability during MEOR under mixed wettability conditions within silicon etched micromodels and to identify the type of oil field (i.e. based on wettability) in which MEOR is likely to be most profitable. To quantify porous media wettability, macro-scale indexes (obtained with techniques such as the Carter or Amott methods) are used regularly. However, these measurements lack the capability for characterization of changes in wettability during MEOR treatment, and only provide macro-scale information. In an effort to understand micro-scale temporal and spatial changes in wettability we measure interfacial curvature from stereo microscope images using level set methods. Curvature, from the perspective of the oil phase, is positive for a concave interface (i.e. water-wet surface) and negative for a convex interface (i.e. oil-wet surface). Thus, shifts in the radius of curvature distribution (i.e. from positive to negative or conversely) are indicative of wettability changes. Both curvature distributions using level-set methods and the Carter method are used to characterize wettability before and after microbial treatment. In preliminary studies aimed at understanding wettability changes due to microbial surface interactions by Bacillus mojavensis JF-2, oil droplets were placed on glass slides suspended in growth media and the resulting contact angle was measured over time. Results showed that a water-wet surface will become more water wet as JF-2 accumulated in the growth media and/or at the oil/water/solid interfaces. Conversely, an oil-wet surface would not become water-wet. These experiments demonstrated that a microbe’s ability to change wettability, as measured by contact angle, is dependent upon the initial wettability state. To study the dependence of wettability changes on initial wettability designer-wet micromodels were prepared by freezing a liquid within a fraction of a micromodel pore space followed by treatment with octodecylthrichlorosilane (OTS). Locations within the micromodel where the liquid was frozen remained water-wet and water-wet to oil-wet surface ratios were produced in ratios: 1:5, 5:5, and 5:1. The method for creating designer-wet micromodels and preliminary results on wettability change using JF-2 within the micromodel system will be presented.

Armstrong, R. T.; Wildenschild, D.

2010-12-01

193

Water transport and purification in nanochannels controlled by asymmetric wettability.  

PubMed

Biomimetic asymmetric nanochannels have recently attracted increasing attention from researchers, especially in the aspect of the asymmetric wettability (a hydrophilic-hydrophobic system), which can be utilized to control the wetting behavior of aqueous media and to offer a means for guiding water motion. By using molecular dynamics simulations, a design for a potentially efficient water filter is presented based on (n, n) single-walled carbon nanotubes, where n = 6, 8, 10 and 12, asymmetrically modified with hydrophilic groups (carboxyl, -COOH) at one tip and hydrophobic groups (trifluoromethyl, -CF(3) ) at the other. The reduced water density on the hydrophobic sides of the functionalized nanotubes are observed in both pure water and aqueous electrolyte solution, except for the functionalized (6, 6) tube, due to the change of dipole orientation of the single-file water wire within it. The functionalized (8, 8) tube can significantly maintain the low water density on the hydrophobic side. Both (6, 6) and (8, 8) tubes have relatively high energy barriers at their tips for ion permeation, which can be obtained by calculating the potential of mean force. Such tip functionalization of a nanotube therefore suggests the great possibilities of water transport and filtration, dominated by asymmetric wettability. The functionalized (8, 8) tube could act as a nanofluidic channel for water purification, not only for ion exclusion but also as a stable water column structure. PMID:21608126

Chen, Qinwen; Meng, Lingyi; Li, Qikai; Wang, Dong; Guo, Wei; Shuai, Zhigang; Jiang, Lei

2011-08-01

194

Parameter and environmental influences on rigid contact lens wettability.  

PubMed

The present investigation was designed to determine the effect of lens parameters and lens environment on measurements of contact angle. The sessile drop contact angle of saline on four rigid [polymethyl methacrylate (PMMA) and silicone/acrylate] contact lens materials was examined with a Ramé-Hart goniometer to determine how front surface radius, drop size, time after drop placement, humidity, and desiccation affect measurements of lens wettability in vitro. Contact angles of Silafocon A and PMMA were relatively uninfluenced by front surface radii between 7.7 and 8.85 and 7.3 to 8.8 mm, respectively. Contact angles of Pasifocon C and modified PMMA were slightly but significantly influenced by front surface radii between 6.4 and 7.5 mm. For drop volumes from 2 to 20 microliter, all materials yielded contact angles, which were unaffected by drop size. The contact angle of lenses stored in the hydrated or dehydrated state was not affected by chamber humidity between 31 and 76%. In the ranges tested, drop size, humidity, and hydration had no significant effect on the contact angle within 1 to 6 min after drop placement. In addition, surface scratches had no effect on lens wettability. The results suggest that goniometry on contact lens surfaces, for the most part, is uninfluenced by lens parameters and environmental conditions. PMID:3189498

Huff, J W; Egan, D J; Katich, M J

1988-09-01

195

Improved Surface wettability of polyurethane films by Ultraviolet Ozone treatment  

SciTech Connect

The wettability of polyurethane (PU) was altered using ultraviolet ozone (UVO) treatment. The effect of UVO treatment on PU surface chemistry was investigated with various experiments. The direct measurement of sessile drops was employed to quantify the static contact angle of different wetting liquids on homogeneous PU films with various UVO treatment times. The contact angle of DI water droplets was decreased to 17.2{sup o} from 70.04{sup o} after 5 min UVO treatment. The surface free energy of PU films was 51.46 mN m{sup -1} before treatment and was increased to 71.5 mN m{sup -1} after being fully treated. X-ray photoelectron spectroscopy (XPS) analysis shows a significant amount of polar functional species (C-O and C-O bonding) were formed on the PU surface by UVO treatment. atomic force microscopy (AFM) characterization shows the PU surface morphology was different before and after UVO treatment. The effect of water washing on UVO treated surface was also investigated. An aging effect study indicates the UVO modification can sustain the improved wettability with limited hydrophobic recovery, where the DI water contact angle remains constant at around 22{sup o} after the UVO treatment.

Kuang, Ping; Lee, Jae-Hwang; Kim, Chang-Hwang; Ho, Kai-Ming; Constant, Kristen

2010-07-01

196

Wettability of low temperature solder alloys for step-soldering  

SciTech Connect

The electronics industry relies on step-soldering during device attachment or subsequent reworking of heavily populated hybrid microcircuits and multilevel networks. Although there are many low to intermediate melting solder alloys that are commercially available, their wettability on typical base metals, such as Cu, Ni, Au, and Sn, are not well characterized. This investigation examines the wetting behavior of several In, Sn, Pb, Bi, and Ag containing solder alloys on Ni-Sn plated aluminum alloy substrates with soldering temperatures ranging from 145 to 200{degrees}C. Two rosin mildly activated (RMA) fluxes were included in the study. The wettability experiments were conducted with a Sandia designed wetting balance system. Wetting differences were observed between the two fluxes. The more active flux gave better wetting results and less variability in the meniscus terminations at the lower soldering temperatures. Wetting generally varied from adequate to very good. The Bi-bearing alloys generally gave the lowest wetting values. Work is in progress to determine the effects of aging on intermetallic growth and subsequent mechanical strength. 12 refs., 12 figs., 2 tabs.

Hosking, F.M.; Vianco, P.T.; Frear, D.R.

1991-01-01

197

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

198

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

199

Effects of aluminium surface morphology and chemical modification on wettability  

NASA Astrophysics Data System (ADS)

Aluminium alloys are some of the predominant metals in industrial applications such as production of heat exchangers, heat pumps. They have high heat conductivity coupled with a low specific weight. In cold working conditions, there is a risk of frost formation on the surface of aluminium in the presence of water vapour, which can lead to the deterioration of equipment performance. This work addresses the methods of surface modification of aluminium and their effect of the underlying surface morphology and wettability, which are the important parameters for frost formation. Three groups of real-life aluminium surfaces of different morphology: unpolished aluminium, polished aluminium, and aluminium foil, were subjected to surface modification procedures which involved the formation of a layer of hydrophilic hyperbranched polyethyleneglycol via in situ polymerization, molecular vapour deposition of a monolayer of fluorinated silane, and a combination of those. The effect of these surface modification techniques on roughness and wettability of the aluminium surfaces was elucidated by ellipsometry, contact angle measurements and atomic force microscopy. We demonstrated that by employing different types of surface modifications the contact angle of water droplets on aluminium samples can be varied from 12° to more than 120°. A crossover from Cassie-Baxter to Wenzel regime upon changing the surface roughness was also observed.

Rahimi, M.; Fojan, P.; Gurevich, L.; Afshari, A.

2014-03-01

200

Salinity Influence on Interfacial Area, Wettability, and NAPL Recovery  

NASA Astrophysics Data System (ADS)

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

Zhong, L.; Valenta, M. M.

2007-12-01

201

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

202

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. 11 figs.

Hall, S.H.

1996-02-13

203

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

SciTech Connect

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

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

2010-12-01

204

Critical capillary channel flow  

NASA Astrophysics Data System (ADS)

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

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

205

Stability of capillary surfaces  

NASA Technical Reports Server (NTRS)

An extensive data set quantifying the stability limits of capillary surfaces for a wide range of fluid properties, container geometry, and input disturbance and orientation does not currently exist. To begin to provide such a data set an experimental apparatus has been designed for which the dynamics and stability of fluid interfaces will be investigated. The apparatus consists primarily of a programmable shaker table and a high speed motion picture and video camera for viewing the fluid surface as drop tower tests will be performed to note the stability of a variety of surface/vessel configurations.

Weislogel, Mark

1991-01-01

206

Alveolar Capillary Dysplasia  

PubMed Central

Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare, fatal developmental lung disorder of neonates and infants. This review aims to address recent findings in the etiology and genetics of ACD/MPV and to raise awareness of this poorly known disease, which may also present as milder, unclassified forms. Successively discussed are what is known about the epidemiology, pathogenesis, pathophysiology, diagnostic indicators and approaches, genetic testing, treatment, and cases of delayed onset. The review concludes with suggestions for future directions to answer the many unknowns about this disorder.

Stankiewicz, Pawel; Steinhorn, Robin H.

2011-01-01

207

Effect of WAG injection and rock wettability on oil recovery during carbon dioxide flooding  

SciTech Connect

Previous studies to determine the extent of oil trapping by water during CO/sub 2/ WAG flooding have shown that rock wettability strongly affects this trapping. A significant trapping occurs in preferentially water-wet rock, and less trapping occurs in oil-wet rock. However, data on trapping in mixed-wettability rock appears to be unavailable in the literature. This paper presents laboratory results of Devonian crude oil displacement from watered-out Berea ad reservoir cores using continuous CO/sub 2/ injection, single-slug CO/sub 2/ injection (followed by water) and CO/sub 2/ WAG injection at miscible reservoir conditions of 120/sup 0/F and 2500 psig. The reservoir cores used in this study were mixed-wettability (Devonian and Muddy formations) and oil-wet (Tensleep formation). The Berea cores used had their wettability artificially altered to simulate these natural wettabilities. The techniques to alter wettability are described in the paper. They included treatment of the rock with crude oil, asphaltenes and silane solutions. The x-ray Photoelectron Spectroscopic method for measuring carbon content of rock surface was used to provide a qualitative measure of wettability of the rock samples.

Huang, E.T.S.; Holm, L.W.

1986-01-01

208

Contiguous Capillary Electrospray Sources and Analytical Devices.  

National Technical Information Service (NTIS)

Contiguous capillaries useful for separating and electrospraying a fluid comprising analyte and electrolyte are provided. The contiguous capillaries have spray tips at one end of the capillaries and electrically conductive portions in proximity to the spr...

G. Janini H. J. Issaq T. D. Veenstra T. P. Conrads

2003-01-01

209

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

210

Wettability and friction coefficient of micro-magnet arrayed surface  

NASA Astrophysics Data System (ADS)

Surface coating is an important part of surface engineering and it has been successfully used in many applications to improve the performance of surfaces. In this paper, magnetic arrayed films with different thicknesses were fabricated on the surface of 316 stainless steel disks. Controllable colloid - ferrofluids (FF) was chosen as lubricant, which can be adsorbed on the magnetic surface. The wettability of the micro-magnet arrayed surface was evaluated by measuring the contract angle of FF drops on surface. Tribological experiments were carried out to investigate the effects of magnetic film thickness on frictional properties when lubricated by FF under plane contact condition. It was found that the magnetic arrayed surface with thicker magnetic films presented larger contract angle. The frictional test results showed that samples with thicker magnetic films could reduce friction and wear more efficiently at higher sliding velocity under the lubrication of FF.

Huang, Wei; Liao, Sijie; Wang, Xiaolei

2012-01-01

211

Evaluation of Reservoir Wettability and its Effect on Oil Recovery  

SciTech Connect

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

Jill S. Buckley

1998-04-13

212

Atmospheric plasma torch treatment of aluminium: Improving wettability with silanes  

NASA Astrophysics Data System (ADS)

This study investigates the effect of atmospheric pressure plasma torch (APPT) treatments on the surface of aluminium alloys. The influence of torch-to-sample distance, speed of treatment and ageing time is analyzed in terms of contact angles and surface energy. Results show that APPT treatment strongly increases the surface energy and wettability of aluminium surfaces. This is related to the formation of polar groups, as Fourier transform infrared (FTIR) spectroscopy has confirmed. In all conditions, hydrophobic recovery of aluminium surfaces takes place. Finally, the compatibility of the APPT treated aluminium substrate with ?-methacryloxypropyltrimethoxysilane (MPS) has been evaluated through adhesion work and spread tension, showing that it is possible to achieve a spontaneous wetting process of silane on aluminium.

Díaz-Benito, B.; Velasco, F.

2013-12-01

213

Dynamic surface wettability of three-dimensional graphene foam  

NASA Astrophysics Data System (ADS)

In this work, three-dimensional graphene foams (GFs) are synthesized and characterized by scanning electron microscope (SEM) and Raman spectroscopy. The SEM images indicate that after the growth of graphene, the graphene covers the surface of nickel (Ni) foam uniformly. Raman spectra show that the percentages of monolayer, bilayer, trilayer, and multilayer graphenes are ~ 58%, ~ 32%, ~ 8%, and ~ 2%, respectively. The contact angle (CA) (~ 12°) of water droplet (3 ?L) on GF is found to be larger than that on Ni foam (~ 107°), indicating that graphenes have changed the surface wettability of the Ni foam. Meanwhile, the dynamic characteristics of CA of water droplet on GF are different from those on Ni foam. The mechanisms for different behaviors are discussed, which are attributed to volatilization and seepage of water droplets.

Huang, Wen-Bin; Wang, Guang-Long; Gao, Feng-Qi; Qiao, Zhong-Tao; Wang, Gang; Chen, Min-Jiang; Tao, Li; Deng, Ya; Sun, Lian-Feng

2014-04-01

214

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

215

Tapered capillary optics  

DOEpatents

A metal or glass wire is etched with great precision into a very narrowly tapering cone which has the shape of the desired final capillary-optics bore. By controlling the rate of removal of the wire from an etchant bath, a carefully controlled taper is produced. A sensor measures the diameter of the wire as it leaves the surface of the etchant. This signal is used for feedback control of the withdrawal speed. The etched wire undergoes a treatment to produce an extremely low surface-roughness. The etched and smoothed wire is coated with the material of choice for optimizing the reflectivity of the radiation being focused. This could be a vacuum evaporation, sputtering, CVD or aqueous chemical process. The coated wire is either electroplated, built up with electroless plating, or encapsulated in a polymer cylinder such as epoxy to increase the diameter of the wire for easier handling and greater robustness. During this process, the wire is vertically oriented and tensioned to assure that the wire is absolutely straight. The coated and electroformed wire is bonded to a flat, rigid substrate and is then periodically segmented by cutting or etching a series of narrow slits or grooves into the wire. The wire is vertically oriented and tensioned during the bonding process to assure that it is straight. The original wire material is then chemically etched away through the slits or otherwise withdrawn to leave the hollow internal bore of the final tapered-capillary optical element.

Hirsch, Gregory (365 Talbot Ave., Pacifica, CA 94044)

1998-01-01

216

On Capillary Rise and Nucleation  

ERIC Educational Resources Information Center

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

Prasad, R.

2008-01-01

217

Functional Reactivity of Cerebral Capillaries  

PubMed Central

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

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

2011-01-01

218

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.; Berthomé, G.

2013-12-01

219

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. 13 figs.

Yeung, E.S.; Xue, Y.

1996-07-30

220

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

221

Metal capillaries for neutron lenses  

NASA Astrophysics Data System (ADS)

The use of metal reflective surfaces should greatly improve the transimission of neutron focusing devices based on glass polycapillary lenses because the longer scattering lengths of many metals allow greater critical angles compared to glass. The neutron transmission of single channel metal capillaries has been studied using cold neutron beams and an imaging neutron detector. Metal capillaries obtained from commercial sources have been studied both as supplied and as treated by chemical flow or electropolishing techniques to compare the transmission performance as a function of the smoothness of the metal surface. The reflectivities calculated from the experimental transmissions vary as a function of internal diameter and of capillary length, but are not sensitive to the various surface treatments studied here. None of the metal capillaries have reflectivities as good as the glass capillaries currently being used.

Reeder, P. L.; Peurrung, A. J.; Sunberg, D. S.; Stoffels, J. J.; Chen-Mayer, H. H.; Mildner, D. F. R.; Sharov, V. A.; Fokin, V. S.

1997-02-01

222

Capillaries for use in a multiplexed capillary electrophoresis system  

DOEpatents

The invention provides a side-entry optical excitation geometry for use in a multiplexed capillary electrophoresis system. A charge-injection device is optically coupled to capillaries in the array such that the interior of a capillary is imaged onto only one pixel. In Sanger-type 4-label DNA sequencing reactions, nucleotide identification (``base calling``) is improved by using two long-pass filters to split fluorescence emission into two emission channels. A binary poly(ethyleneoxide) matrix is used in the electrophoretic separations. 19 figs.

Yeung, E.S.; Chang, H.T.; Fung, E.N.

1997-12-09

223

Capillaries for use in a multiplexed capillary electrophoresis system  

DOEpatents

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

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

1997-12-09

224

Capillary ratchet: Hydrodynamics of capillary feeding in shorebirds  

NASA Astrophysics Data System (ADS)

Bill morphologies are highly specialized to particular foraging strategies in birds, as is apparent from the large diversity of beak shapes observed in nature. Here we present an experimental and analytical study of capillary feeding in shorebirds. We highlight the critical role of contact angle hysteresis in capillary feeding. Our study provides a simple physical rationalization for the observation of multiple mandibular spreading cycles in feeding, necessary to overcome contact line resistance. We also find a unique geometrical optima in beak opening and closing angles for the most efficient drop transport. This capillary ratchet mechanism may also find applications in micro scale fluid transport, such as valveless pumping of fluid drops.

Prakash, Manu; Quere, David; Bush, John

2008-03-01

225

Plasma/thermal-driven the rapid wettability transition on a copper surface  

NASA Astrophysics Data System (ADS)

A simple and time-saving method to realize the reversible wettability transition is reported. Through a solution-immersion process followed by stearic acid modification, a superhydrophobic surface was prepared on the copper surface. After being treated by air-plasma exposure, the surface wettability was converted into superhydrophilicity. XPS analysis demonstrated that the incorporation of oxygen species by air-plasma activation accounted for the highly hydrophilic character of the surface. Upon annealing the plasma-treated surface in air, the non-oxidized alkyl chains were transferred to the surface for recovery the superhydrophobicity. It was found that the recovery was fast upon annealing at a relative high temperature. By the alternation of air-plasma treatment and annealing process, the rapid reversible wettability transition between superhydrophobic and superhydrophilic state was realized. The shortest processing time for a whole reversible wettability transition was 21 min.

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

2011-02-01

226

Wettability Alteration of Carbonate Rock Mediated by Biosurfactant Produced from High Starch Agricultural Effluents.  

National Technical Information Service (NTIS)

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, su...

G. Bala J. T. Liang M. Salehi S. Fox S. Johnson

2006-01-01

227

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

228

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

Microsoft Academic Search

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

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

2010-01-01

229

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

PubMed

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

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

2013-03-25

230

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

231

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, Jürgen

2014-07-01

232

Wettability measurement apparatus for porous material using the modified Washburn method  

NASA Astrophysics Data System (ADS)

In this work a cost-effective instrument for measuring the wettability of powder materials was designed and developed, which works on the modified Washburn method. The instrument measures the mass gain against time due to penetration of the liquid into the powder materials using a microbalance and LabVIEW-based data acquisition system. The wettability characteristic of different powders was determined from the contact angle using the modified Washburn equation. To demonstrate the performance of the developed instrument, the wettability of as-received corn starch and nano-coated corn starch powders was estimated with water as a test liquid. The corn starch powders coated with hydrophilic grade (Aerosil 200P) and hydrophobic grade (Aerosil R972) nanoparticles at different coating levels showed expected changes in their contact angle. Some of the results were also verified against the available standard instrument for wettability measurement and found to be consistent. The present configuration of the instrument costs about 500 US which is 15 to 20 times less than the available advanced models. The developed instrument is thus a cost-effective solution for wettability measurement which can be used for materials in food processing, pharmaceuticals, horticulture, textile manufacturing, civil engineering etc. The developed instrument is expected to help many small scale industries or research labs who cannot afford an expensive instrument for wettability studies.

Thakker, Manish; Karde, Vikram; Shah, Dinesh O.; Shukla, Premal; Ghoroi, Chinmay

2013-12-01

233

Wettability transition induced transformation and entrapment of polymer nanostructures in cylindrical nanopores.  

PubMed

We apply the concept of wettability transition to manipulate the morphology and entrapment of polymer nanostructures inside cylindrical nanopores of anodic aluminum oxide (AAO) membranes. When AAO/polystyrene (PS) hybrids, i.e., AAO/PS nanorods or AAO/PS nanotubes, are immersed into a polyethylene glycol (PEG) reservoir above the glass transition temperature of PS, a wettability transition from wetting to nonwetting of PS can be triggered due to the invasion of the more wettable PEG melt. The wettability transition enables us to develop a nondestructive method to entrap hemispherically capped nanorods inside nanopores. Moreover, we can obtain single nanorods with the desired aspect ratio by further dissolving the AAO template, in contrast to the drawbacks of nonuniformity or destructiveness from the conventional ultrasonication method. In the case of AAO/PS nanotubes, the wettability transition induced dewetting of PS nanotube walls results in the disconnection and entrapment of nonwetting PS domains (i.e., nanospheres, nanocapsules, or capped nanorods). Moreover, PEG is then washed to recover the pristine wettability of PS on the alumina surface; further annealing of the PS nanospheres inside AAO nanopores under vacuum can generate some unique nanostructures, particularly semicylindrical nanorods. PMID:22004408

Feng, Xunda; Mei, Shilin; Jin, Zhaoxia

2011-12-01

234

Capillary electrophoresis and capillary flow injection analysis with electrochemical detection.  

PubMed

Measurements by capillary flow injection analysis (CFIA) and capillary electrophoresis (CE) in conjunction with electrochemical detection are described. The detection is based on an end-column electrode arrangement. Several novel electrodes, such as a spherical gold electrode and a dual-microdisk electrode, are presented and characterized regarding their analytical utility. In order to improve the selectivity of CFIA, dual-electrode and multiple-pulse detection are studied using couples of cyanometallates or metallocenes. Capillary electrophoretic experiments with amperometric detection are performed using 50 microm i.d. capillaries without any electrical-field decoupler. The practicality and analytical characteristics of this detection strategy are illustrated for the separation of serotonin and some biological precursors and metabolites of neurotransmitter substances. PMID:15048346

Matysik, F M; Backofen, U

1996-09-01

235

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

236

What is a capillary malformation?  

PubMed

Today, the designation "capillary malformation" is widely used as a modern name for what was formerly called a nevus flammeus or port-wine stain. This new terminology, however, is inaccurate and ambiguous. There are at least nine different skin disorders fulfilling the criteria of a capillary malformation. Examples include nevus anemicus, cutis marmorata telangiectatica congenita, angiokeratoma circumscriptum, and several vascular lesions that, in the author's view, do not represent nevi, such as the nuchal or glabellar salmon patch and the cutaneous changes of Rendu-Osler disease. Hence, I propose that we should use "capillary malformation" as an umbrella term and not as a name for a specific cutaneous entity. PMID:19022106

Happle, Rudolf

2008-12-01

237

Chemical modification of polymeric surfaces to promote wettability and reactivity  

NASA Astrophysics Data System (ADS)

For the past few years, low-k dielectric polymers have had a major impact on the advanced integrate circuit technologies. Their potential use as interlayer dielectric combined with a low resistivity metal as the conducting line (e.g. copper) in interconnects can reduce the resistivity-capacity delay. However, in order to successfully integrate copper and low-k dielectrics for further use, it is first necessary to understand the interfacial interaction between copper and low-k dielectric. This thesis work presents a systematic study with the primary goal of improving the polymer surface wettability and reactivity. Two hydrocarbon polymers, SiLK(TM) and Parylene, were used in this study, and the polymer surfaces were modified by either acid or plasma treatments. The change of surface morphology and surface chemistry due to the treatment was analyzed by atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS), respectively. A significant decrease of water droplet contact angle after the surface treatment reveals that the polymer surface wettability increases. It is found that the main factor in reducing the water droplet contact angle is the formation of oxygen and/or nitrogen functional groups on the polymer surface rather than an increase in the polymer surface roughness. The plasma treatment introduces a larger amount of functional groups onto the polymer surface than the acid treatment. The SiLK's crosslink structure is better withstanding the plasma force than the Parylene's linear polymer. Consequently, there are larger amounts of functional groups formed on the SILK surface than on the Parylenc surface. An additional study reveals that the formation of functional groups on the polymer surface also increases the polymer surface reactivity and allows Tetrasulfide self-assembled monolayer growth on the treated polymer surfaces. The existence of functional groups and Tetrasulfide moiety markedly improves the copper interfacial interaction. It was observed that copper undergoes a reaction with oxygen functional groups, nitrogen functional groups and Tetrasulfide moiety. Further study of metallorganic Cu(hfac)2 adsorption indicates that the existence of functional groups on the plasma-treated polymer surface significantly enhances the Cu(hfac)2 chemisorption onto the polymer surface. The Cu(hfac)2 self-limiting growth behavior remains after it is adsorbed onto the polymer surface.

Pimanpang, Samuk

238

Capillary electrophoresis electrospray ionization mass spectrometry interface  

DOEpatents

The present invention is an interface between a capillary electrophoresis separation capillary end and an electrospray ionization mass spectrometry emitter capillary end, for transporting an anolyte sample from a capillary electrophoresis separation capillary to a electrospray ionization mass spectrometry emitter capillary. The interface of the present invention has: (a) a charge transfer fitting enclosing both of the capillary electrophoresis capillary end and the electrospray ionization mass spectrometry emitter capillary end; (b) a reservoir containing an electrolyte surrounding the charge transfer fitting; and (c) an electrode immersed into the electrolyte, the electrode closing a capillary electrophoresis circuit and providing charge transfer across the charge transfer fitting while avoiding substantial bulk fluid transfer across the charge transfer fitting. Advantages of the present invention have been demonstrated as effective in providing high sensitivity and efficient analyses.

Smith, Richard D. (Richland, WA); Severs, Joanne C. (Hayward, CA)

1999-01-01

239

Some invariant solutions to two-phase fluid displacement problems including capillary effect  

SciTech Connect

Analytical investigation of the two-phase displacement problem that considers capillary force is one of the most important and difficult problems in the theory of fluid flow through porous media. This paper presents some invariant solutions on the subject, including a self-similar solution for the axisymmetric case, a self-similar solution in a linear, isoclinal reservoir that considers the effects of gravity and capillary forces simultaneously, and a progressive wave solution corresponding to a stabilized zone of saturation distribution. The relations and differences among (1) a model that completely includes capillary effect, (2) a model that considers capillary action partially and implicitly (the Buckley-Leverett model), and (3) a model that completely ignores capillary effect are indicated and discussed.

Chen, Z.X.

1988-05-01

240

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

241

Capillary fracturing in granular media.  

PubMed

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

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

2012-06-29

242

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

243

Surface Tension and Capillary Rise  

ERIC Educational Resources Information Center

Discussion of the shortcomings of textbook explanations of surface tension, distinguishing between concepts of tension and capillary rise. The arguments require only a clear understanding of Newtonian mechanics, notably potential energy. (DF)

Walton, Alan J.

1972-01-01

244

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

245

Droplet motion on designed microtextured superhydrophobic surfaces with tunable wettability.  

PubMed

Superhydrophobic surfaces have shown promising applications in microfluidic systems as a result of their water-repellent and low-friction properties over the past decade. Recently, designed microstructures have been experimentally applied to construct wettability gradients and direct the droplet motion. However, thermodynamic mechanisms responsible for the droplet motion on such regular rough surfaces have not been well understood such that at present specific guidelines for the design of tunable superhydrophobic surfaces are not available. In this study, we propose a simple but robust thermodynamic methodology to gain thorough insight into the physical nature for the controllable motion of droplets. On the basis of the thermodynamic calculations of free energy (FE) and the free-energy barrier (FEB), the effects of surface geometry of a pillar microtexture are systematically investigated. It is found that decreasing the pillar width and spacing simultaneously is required to lower the advancing and receding FEBs to effectively direct droplets on the roughness gradient surface. Furthermore, the external energy plays a role in the actuation of spontaneous droplet motion with the cooperation of the roughness gradient. In addition, it is suggested that the so-called "virtual wall" used to confine the liquid flow along the undesired directions could be achieved by constructing highly advancing FEB areas around the microchannels, which is promising for the design of microfluidic systems. PMID:18788770

Fang, Guoping; Li, Wen; Wang, Xiufeng; Qiao, Guanjun

2008-10-21

246

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

247

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 µm) 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

248

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

Microsoft Academic Search

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

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

249

Microprism using capillary alignment  

NASA Astrophysics Data System (ADS)

When a microstructure is placed on a droplet, the structure is positioned and remains at a particular position due to capillary forces. By using this phenomenon, two-dimensional arrangements on droplets have been widely developed. In this study, we fabricate a three-dimensional structure (prism shape) by placing two circular plates on a droplet. The paper explains the dynamics of the positioning both experimentally and numerically. Through experiment and simulation, we found that the rotational positioning is determined by surface tension and the two plates are supported by internal pressure and surface tension. The apex angle of the prism can be easily tuned by changing its volume. As described at the end of the paper, a prism composed of a droplet of silicone oil and two transparent circular SU-8 plates is encapsulated by depositing an organic Parylene membrane. The shape of the liquid is fixed, and a non-evaporative and non-deformable prism is formed with a volume of less than 1 mm3.

Takei, Atsushi; Yoshihata, Yuta; Shimoyama, Isao

2011-08-01

250

Effect of WAG injection and rock wettability on oil recovery during CO/sub 2/ flooding  

SciTech Connect

Previous studies to determine the extent of oil trapping by water during CO/sub 2/ water-alternating-gas (WAG) flooding have shown that rock wettability strongly affects this trapping. A significant trapping occurs in water-wet rock, and less trapping occurs in oil-wet rock. This paper presents laboratory results of Devonian crude oil displacement from watered-out Berea and reservoir cores by use of continuous CO/sub 2/ injection, single-slug CO/sub 2/ injection (followed by water), and CO/sub 2/ WAG injection at miscible reservoir conditions of 120/sup 0/F and 2,500 psig (49/sup 0/C and 17.2 MPa). The reservoir cores used in this study were mixed-wet (Devonian and Muddy formations) and oil-wet (Tensleep formation). The Berea cores used had their wettability artificially altered to simulate these natural wettabilities. The X-ray photoelectron spectroscopic (XPS) method for measuring carbon content of rock surface was used to provide a qualitative measurement of wettability of the rock samples. The results of the study indicated that the experimental wettability-altering technique came close to duplicating reservoir rock wettability. The oil recovery data at the end of 1 PV fluid injection (continuous CO/sub 2/ or WAG CO/sub 2/) indicated that (1) in preferentially water-wet Berea cores, more than 45% of the waterflood residual oil trapped by CO/sub 2/ WAG; (2) in mixed-wettability Berea cores, 15 to 20% of the waterflood residual oil was trapped; and (3) in oil-wet Berea cores, less than 5% residual oil was trapped.

Huang, E.T.S.; Holm, L.W.

1988-02-01

251

Ceramic Wick For Capillary-Pumped Heat Pipe  

NASA Technical Reports Server (NTRS)

Fibrous ceramic wick allows choice of working fluid and high-temperature fabrication and/or operation. Wick material resists degradation at temperatures from -195 to +1,500 degrees C. Liquid refrigerant fills bore of silica/alumina wick. After flowing by capillary action through pores of wick, refrigerant evaporates from finned outer surface of wick and enters heat pipe, flowing toward condenser section.

Seidenberg, Benjamin; Swanson, Theodore

1989-01-01

252

Pulsatility of Parafoveal Capillary Leukocytes  

PubMed Central

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

Martin, Joy A.; Roorda, Austin

2009-01-01

253

Electrical resistance of a capillary endothelium  

PubMed Central

The electrical resistance of consecutive segments of capillaries has been determined by a method in which the microvessels were treated as a leaky, infinite cable. A two-dimensional analytical model to describe the potential field in response to intracapillary current injection was formulated. The model allowed determination of the electrical resistance from four sets of data: the capillary radius, the capillary length constant, the length constant in the mesentery perpendicular to the capillary, and the relative potential drop across the capillary wall. Of particular importance were the mesothelial membranes covering the mesenteric capillaries with resistances several times higher than that of the capillary endothelium. 27 frog mesenteric capillaries were characterized. The average resistance of the endothelium was 1.85 omega cm2, which compares well with earlier determinations of the ionic permeability of such capillaries. However, heterogeneity with respect to resistance was observed, that of 10 arterial capillaries being 3.0 omega cm2 as compared with 0.95 omega cm2 for 17 mid- and venous capillaries. The average in situ length constant was 99 micrometers for the arterial capillaries and 57 micrometers for the mid- and venous capillaries. It is likely that the ions that carry the current must move paracellularly, through junctions that are leaky to small solutes.

1981-01-01

254

Wettability study of modified silicon dioxide surface using environmental scanning electron microscopy  

SciTech Connect

The wettability analysis is often used to characterize a surface in micro and nanometer scale. At these small scales, effects of the contact line tension are also expected to play a significant role. Wettability effect is studied using environmental scanning electron microscopy on silicon dioxide surface modified by a low-energy electron irradiation method. Electron-induced wettability variation and patterning at micrometer scale on silicon dioxide substrate allow investigating the contact angle dependence on the water droplet line curvature and calculating values of the line tension of a three-phase system (solid-liquid-vapor) of about 10{sup -9} J/m that is consistent with theoretical estimations. It is found that the sign of the line tension alters from positive for hydrophilic surface to negative for hydrophobic one.

Aronov, Daniel; Rosenman, Gil; Barkay, Zahava [Department of Physical Electronics, School of Electrical Engineering, Tel Aviv University, 69978 (Israel); Wolfson Applied Materials Research Center, Tel Aviv University, 69978 (Israel)

2007-04-15

255

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

256

Wettability alteration of model sandstone surfaces by vapor-phase treatment with organosilanes  

SciTech Connect

The wettability of a rock-fluid system has a major influence on the amount of residual oil in a reservoir and its ease of recovery. We have investigated a technique for modifying the natural water-wetness of clean, dry mineral samples by chemically incorporating organosilanes onto their surfaces (silylation). The goal is to provide simulated core samples with different degrees of wettability. Data from wettability measurements on these model cores could then be compared to that obtained on actual reservoir core samples. Discussion will specifically focus on: (1) comparison of quartz plates silylated by our vapor-phase technique vs. a solvent-phase treatment; (2) relative performance of two different types of organosilanes; and (3) effect of temperature.

Takach, N.E.; Bennett, L.B.; Douglas, C.B.; Andersen, M.A.; Thomas, D.C.

1988-08-01

257

[Clinical aspects of capillary malformations].  

PubMed

Capillary malformations (CM) are defects of the dermal capillary bed. These slow-flow malformations can affect any part of the body and are always lateralized, despite Unna's naevus. Present at birth, they grow proportionally with the child. In rare instance, they can be part of a more complex syndrome such as Sturge-Weber syndrome. Ectatic CMs of telangiectatic types can be cutaneous, isolated, multiples, diffuse or generalized. In rare instance, they can be associated with epidermal modifications. They can also be part of a syndrome such as Fabry disease, Osler-Weber-Rendu disorder or Cutis marmorata telangiectatica congenita (CMTC). This chapter details the various clinical aspects of CMs. PMID:17007980

Bataille, A-C; Boon, L-M

2006-01-01

258

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 mm•h-1. The 10% BC decreased runoff by up to 40%. At higher rainfall intensities (45 and 55 mm•h-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

259

Novel absorption detection techniques for capillary electrophoresis.  

National Technical Information Service (NTIS)

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 challen...

Y. Xue

1994-01-01

260

Genetics Home Reference: Microcephaly-capillary malformation syndrome  

MedlinePLUS

... help with understanding microcephaly-capillary malformation syndrome? angiogenesis ; apoptosis ; autophagy ; autosomal ; autosomal recessive ; capillaries ; cell ; degrade ; developmental delay ; ...

261

Adsorption Behavior of Dodecylamine and its Effect on the Wettability and Corrosion of Carbon Steel  

NASA Astrophysics Data System (ADS)

The adsorption behavior of dodecylamine and its effect on the wettability and corrosion of carbon steel in hydrochloric acid solution were studied. Polarization data suggest that inhibition of carbon steel corrosion is due to geometric blocking effect of adsorbed dodecylamine molecules on the metal surface, which leads to the formation of a monolayer on the metal. Phase images measured by tapping-mode atomic force microscopy (AFM) reveal different properties of the surface with and without various concentrations of dodecylamine. AFM force-distance curves indicate that sample surface exhibits adhesion characteristic after the adsorption of dodecylamine. Contact angle measurements show that dodecylamine reduces surface wettability obviously.

Chen, Z. Y.; Guo, X. P.; Zhang, Q.

262

Polymer stretch in two-phase microfluidics: Effect of wall wettability  

PubMed Central

Polymer stretching in two-phase microfluidics is investigated by dissipative particle dynamics. The flow patterns can be controlled by wall wettability, flowrate ratio between two phases, and Reynolds number (Re). For neutral and partially wettable walls, segmented flows are formed and polymer stretching can be controlled by Re and segment length. At high Re, stratified flows are observed and the extension ratio can be tuned by the flowrate ratio. For nonwettable walls, slug flows are formed and polymer stretching can be controlled by Re and slug length. At high Re or flowrate ratio, annular flows are observed and high extension ratio can be easily attained.

Hu, Ssu-Wei; Sheng, Yu-Jane; Tsao, Heng-Kwong

2012-01-01

263

Neutron transmission through curved nickel capillaries  

NASA Astrophysics Data System (ADS)

Capillaries with metal surfaces can improve the transmission of thermal and cold neutrons for focusing devices on account of their greater critical angle and, therefore, greater angular acceptance than glass capillaries. The transmission characteristics of nickel tubes have been measured with both white beam and monochromatic neutrons. Results are given for curved nickel capillaries, and are compared with experimental results for glass capillaries and with results of computer simulations of the measurements.

Fokin, V. S.; Chen-Mayer, H. H.; Sharov, V. A.; Mildner, D. F. R.

1997-02-01

264

Multiplexed fluorescence detector system for capillary electrophoresis  

DOEpatents

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

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

1994-06-28

265

Altering Reservoir Wettability to Improve Production from Single Wells  

SciTech Connect

Many carbonate reservoirs are naturally fractured and typically produce less than 10% original oil in place during primary recovery. Spontaneous imbibition has proven an important mechanism for oil recovery from fractured reservoirs, which are usually weak waterflood candidates. In some situations, chemical stimulation can promote imbibition of water to alter the reservoir wettability toward water-wetness such that oil is produced at an economic rate from the rock matrix into fractures. In this project, cores and fluids from five reservoirs were used in laboratory tests: the San Andres formation (Fuhrman Masho and Eagle Creek fields) in the Permian Basin of Texas and New Mexico; and the Interlake, Stony Mountain, and Red River formations from the Cedar Creek Anticline in Montana and South Dakota. Solutions of nonionic, anionic, and amphoteric surfactants with formation water were used to promote waterwetness. Some Fuhrman Masho cores soaked in surfactant solution had improved oil recovery up to 38%. Most Eagle Creek cores did not respond to any of the tested surfactants. Some Cedar Creek anticline cores had good response to two anionic surfactants (CD 128 and A246L). The results indicate that cores with higher permeability responded better to the surfactants. The increased recovery is mainly ascribed to increased water-wetness. It is suspected that rock mineralogy is also an important factor. The laboratory work generated three field tests of the surfactant soak process in the West Fuhrman Masho San Andres Unit. The flawlessly designed tests included mechanical well clean out, installation of new pumps, and daily well tests before and after the treatments. Treatments were designed using artificial intelligence (AI) correlations developed from 23 previous surfactant soak treatments. The treatments were conducted during the last quarter of 2006. One of the wells produced a marginal volume of incremental oil through October. It is interesting to note that the field tests were conducted in an area of the field that has not met production expectations. The dataset on the 23 Phosphoria well surfactant soaks was updated. An analysis of the oil decline curves indicted that 4.5 lb of chemical produced a barrel of incremental oil. The AI analysis supports the adage 'good wells are the best candidates.' The generally better performance of surfactant in the high permeability core laboratory tests supports this observation. AI correlations were developed to predict the response to water-frac stimulations in a tight San Andres reservoir. The correlations maybe useful in the design of Cedar Creek Anticline surfactant soak treatments planned for next year. Nuclear Magnetic Resonance scans of dolomite cores to measure porosity and saturation during the high temperature laboratory work were acquired. The scans could not be correlated with physical measurement using either conventional or AI methods.

W. W. Weiss

2006-09-30

266

An experimental analysis of adiabatic capillary tubes  

Microsoft Academic Search

This paper presents an experimental study on capillary tubes commonly used as expansion devices in household refrigerators and freezers. The paper discusses the details of the experimental facility that has been developed and used to generate reliable experimental data within an acceptable level of uncertainty. The investigations include the effect of capillary length, capillary diameter, refrigerant subcooling, condensing pressure and

C. Melo; R. T. S. Ferreira; C. Boabaid Neto; J. M. Gonçalves; M. M. Mezavila

1999-01-01

267

Brazing Beryllium by Capillary Flow.  

National Technical Information Service (NTIS)

Six silver-base braze alloys (including some high in copper), with a high tolerance for adverse braze conditions, were developed to give maximum capillary flow in unplated beryllium sheet without flux at 1400F to avoid loss of base metal wrought propertie...

A. G. Metcalfe R. G. Bogowitz

1968-01-01

268

Quasi Steady Capillary Corner Flow  

NASA Astrophysics Data System (ADS)

It is possible to drain slender containers filled with wetting liquids via capillary flows along the interior corners of the container. Usually the well established equations governing such flows demand numerical techniques. In the case of container draining unique boundary conditions resulting from local section geometry allow for a quasi-steady assumption and in turn permit analytical solutions. The quasi-steady assumption may also be employed for certain problems in which the corner flows cause passive capillary migration of the fluid within the container. The analytic solutions are useful because of the ease in which geometric effects may be observed. Container draining and capillary migration by means of corner flows are studied in a variety of container geometries. It is shown that careful selection of cross sectional shape can be used to maximize drain rates and minimize capillary migration times. Three-dimensional effects for these flows are investigated in tapering containers. Some simple micro-scale experiments are reported that provide confidence in the assumptions and application of the important boundary conditions that enable the solutions.

Baker, John Alex

269

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

270

Capillary blood collection in haematology  

PubMed Central

A capillary blood collection technique which facilitates the estimation of routine haematological parameters, including platelet count and sedimentation rate, is described. The technique requires 0·5 ml of blood, allows closer reproducibility than pipette collection methods, is suitable for monitoring blood counts in patients receiving cytotoxic agents, and can be integrated with semi-and fully-automated production lines. Images

Stuart, J.; Barrett, B. A.; Prangnell, D. R.

1974-01-01

271

Capillary electrophoresis in food analysis  

Microsoft Academic Search

Unlike other chromatographic methods such as gas chromatography and high performance liquid chromatography which were routinely used in almost all food labs, capillary electrophoresis is relatively a novice in food science, the detection limits and low process sample volume is the Achilles’ heel of this technique. Nevertheless, with ease of its high resolving power, rapid method development, easy sample preparation

Yiyang Dong

1999-01-01

272

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

NASA Astrophysics Data System (ADS)

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

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

2010-12-01

273

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

274

Gradient elution in capillary electrochromatography  

SciTech Connect

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

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

1997-08-01

275

Development of a Contingency Capillary Wastewater Management Device  

NASA Technical Reports Server (NTRS)

The Personal Body .Attached Liquid Liquidator (PBALL) is conceived as a passive, capillary driven contingency wastewater disposal device. In this contingency scenario, the airflow system on the NASA Crew Exploration Vehicle (CEV) is assumed to have failed, leaving only passive hardware and vacuum vent to dispose of the wastewater. To meet these needs, the PBALL was conceived to rely on capillary action and urine wetting design considerations. The PBALL is designed to accommodate a range of wetting conditions, from 0deg < (theta)adv approx. 90deg, be adaptable for both male and female use, collect and retain up to a liter of urine, minimize splash-back, and allow continuous drain of the wastewater to vacuum while minimizing cabin air loss. A sub-scale PBALL test article was demonstrated on NASA's reduced gravity aircraft in April, 2010.

Thomas, Evan A.

2010-01-01

276

Enhanced wettability performance of ultrathin ZnO nanotubes by coupling morphology and size effects  

NASA Astrophysics Data System (ADS)

In this work, we report on the detailed characterization and mechanism analysis of the improved wettability performance of a new type of ZnO nanostructure, the ultrathin ZnO nanotube, whose growth is induced by screw-dislocation. The newly discovered enhanced wettability properties are suggested to be caused by coupling the morphology and size effects of the nanostructured surface. These ultrathin nanotubes with low density and small dimension form a wet-hair-like hierarchical morphology, which shows a further improved superhydrophobic property with an 8.6 +/- 1.6° larger contact angle than that of ZnO nanorods due to the morphology effect. In addition, owing to the large surface to volume ratio and increased effective UV-irradiated area of the ultrathin tubular structure, the ZnO nanotubes exhibit ~5 times faster superhydrophobicity to superhydrophilicity conversion speed than nanorods under 254 nm UV illumination. Furthermore, UV light with a wavelength of 254 nm exhibits ~40 times faster wettability conversion speed for nanotubes than that of 365 nm, which is suggested to be a result of the band gap shift at the nanoscale. The combined advantages of enhanced superhydrophobicity, improved sensitivity, and faster conversion speed by coupling morphology and size effects of these ZnO nanotubes should give them broad applications in self-cleaning surfaces and wettability switches.

Yang, Peihua; Wang, Kun; Liang, Zhiwen; Mai, Wenjie; Wang, Cheng-Xin; Xie, Weiguang; Liu, Pengyi; Zhang, Long; Cai, Xiang; Tan, Shaozao; Song, Jinhui

2012-08-01

277

Thermal Annealing Treatment to Achieve Switchable and Reversible Wettability on ZnO Nanowires Surface  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanostructured surfaces can be reversibly altered from hydrophobicity to hydrophilicity in response to ultraviolet light or plasma treatment. In this paper, a thermal annealing procedure was used to tune ZnO nanowires' surface wettability, and the switchable reversible wettability was achieved. ZnO nanowires were synthesized by a simple solution method. The surfaces of as-synthesized ZnO nanowires demonstrated a superhydrophobicity with water contact angle of 151°. After a high temperature treatment (>300°C) for 20 minutes, their superhydrophobicity was transited to superhydrophilicity with water contact angle of < 10°. It was noted that this transition was very short (less than half minutes) when the annealing temperature is more than 400 °C. The high-thermal annealed superhydrophilic ZnO surfaces were recovered to superhydrophobicity after a low-temperature (~100 °C) procedure in 4 days. Thus, the tunable properties of ZnO surface energy result in reversible wettability between superhydrophobicity and superhydrophilicity. This tunable wettability can be explained based on ZnO as a semiconductor material, which provides different numbers of oxygen vacancies under different temperatures. This result will extend applications of ZnO nanomaterials to many important fields, such as microfluidic devices, chemical sensors and biosensors.

Liu, Changsong; Zheng, Dongmei; Zhou, Jigen; Wan, Yong; Li, Zhiwen

2011-06-01

278

Wettability between zirconia ceramics and the liquid metals copper, nickel and cobalt  

Microsoft Academic Search

The wettability conditions between ceramics and liquid metal phases are of importance in the technology of cermets. In the presence of a liquid phase during sintering of metal-ceramic powder composite material, the density, microstructure and mechanical properties are influenced by the wetting behaviour at the interface. The wetting in a solid liquid vapour system, in thermodynamic equilibrium, is characterized by

P. Nikolopoulos; D. Sotiropoulou

1987-01-01

279

Acid-etching and Hydration Influence on Dentin Roughness and Wettability  

Microsoft Academic Search

Adhesion of restorative and protective materials to dentin is an important requirement for operative and preventive dentistry. Wettability and roughness are dentin substrate conditions that are critical to establishing good adhesion. This study examined superficial and deep dentin for variations in water contact angle measurements and roughness for polished, etched, dehydrated, and rehydrated states. Superficial and deep dentin disks from

J. I. Rosales; G. W. Marshall; S. J. Marshall; L. G. Watanabe; M. Toledano; M. A. Cabrerizo; R. Osorio

1999-01-01

280

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

281

Wettability of Brazing Alloys on Molybdenum and TZM (Mo-Ti-Zr Alloy).  

National Technical Information Service (NTIS)

Vacuum brazing studies have been performed on molybdenum and TZM (0.5Ti-0.08Zr-Mo). Wettability tests have been conducted for nineteen braze metal filler alloys on molybdenum and thirty-two braze metal filler alloys on TZM over a wide range of temperature...

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

1988-01-01

282

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

PubMed Central

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

Lin, Meng C.; Svitova, Tatyana F.

2010-01-01

283

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

National Technical Information Service (NTIS)

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...

G. A. Bala K. B. Barrett S. L. Eastman M. D. Herd J. D. Jackson

1993-01-01

284

Impact of miscible flooding on wettability, relative permeability, and oil recovery  

SciTech Connect

This paper reports that the fluid-flow effects in miscible gas processes were studied in several series of corefloods involving water-wet, intermediate-wet, and oil-wet reservoir systems. Three more series of floods were conducted in Berea cores for the same three crude oils used in the previous set. Each of the coreflood series involved three cycles of water and miscible gasfloods, with each cycle consisting of the steps necessary to cover the range of saturations from connate water to miscible flood residual oil saturation (ROS). The results from these flow tests revealed that the oil/water relative permeabilities, saturations, and oil recoveries can be significantly different from cycle to cycle, indicating alterations in the in-situ wettability caused by miscible flooding. These wettability alterations had a significant positive effect on the miscible flood oil recoveries in the case of intermediate-wet and oil-wet reservoirs, while their influence in a strongly water-wet reservoir was negligible. In some cases, a mixed-wettability condition developed as a result of miscible flooding, resulting in higher subsequent waterflood oil recoveries. The water/oil relative permeability ratios have been used to identify the development of mixed-wettability in cores.

Rao, D.N.; Girard, M.; Sayegh, S.G. (Petroleum Recovery Inst. (GB))

1992-05-01

285

Advances in understanding the relationship between rock wettability and high-frequency dielectric response  

Microsoft Academic Search

Previous studies have shown that wettability has an effect on the complex permittivity of rock in a wide frequency interval. At low frequencies (Several experiments carried out on synthetic porous media and reservoir rocks made strongly oil wet using a sylanisation process have been published by the authors [Rev. Inst. Fr. Pet. 53 (1994) 771; Bona, N., Rossi, E., Capaccioli,

N Bona; A Ortenzi; S Capaccioli

2002-01-01

286

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

National Technical Information Service (NTIS)

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

M. M. Sharma G. J. Hirasaki

2002-01-01

287

The enhancement of wettability of SiC particles in cast aluminium matrix composites  

Microsoft Academic Search

Many methods have been proposed to overcome the problem of poor wettability between ceramic reinforcement particles and molten aluminium for metal matrix composite (MMC) production by casting. Some of these methods are expensive and complex, and a cheap and simple technique still to be found.In this paper, an innovative approach to fabricating cast MMCs is proposed. In order to study

J. Hashim; L. Looney; M. S. J. Hashmi

2001-01-01

288

The wettability of SiC particles by molten aluminium alloy  

Microsoft Academic Search

A critical step in the processing of cast, particle reinforced, metal matrix composites (MMCs) is the incorporation of the ceramic particles into the molten matrix alloy. Therefore, in a foundry MMC fabrication method, wettability of the reinforcement particles by the matrix alloy is one aspect of the process that must be optimised. In general, the reinforcement ceramic particles are very

J. Hashim; L. Looney; M. S. J. Hashmi

2001-01-01

289

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

290

A rectangular capillary suction apparatus  

SciTech Connect

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

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

1994-06-01

291

Wettability of amorphous and nanocrystalline Fe78B13Si9 substrates by molten Sn and Bi  

PubMed Central

The wettability of amorphous and annealing-induced nanocrystalline Fe78B13Si9 ribbons by molten Sn and Bi at 600 K was measured using an improved sessile drop method. The results demonstrate that the structural relaxation and crystallization in the amorphous substrates do not substantially change the wettability with molten Bi because of their invariable physical interaction, but remarkably deteriorate the wettability and interfacial bonding with molten Sn as a result of changing a chemical interaction to a physical one for the atoms at the interface.

2011-01-01

292

Wettability of poultry litter biochars at variable pyrolysis temperatures and their impact on soil wettability and water retention relationships  

NASA Astrophysics Data System (ADS)

To reduce the impact of poultry farming on greenhouse gas emissions, poultry farming waste - poultry litter - can be converted to biofuel and biochar through slow-pyrolysis, with the biochar added to agricultural soil for nutrient enrichment and carbon sequestration. While biochars from source materials other than poultry litter have been shown to sequester carbon and increase soil fertility, there is considerable variability in biochar behavior - even with biochars created from the same source material. This situation is exacerbated by our limited understanding of how biochars alter physical, chemical, and biological processes in agricultural soils. The focus of this work is to develop a mechanistic understanding of how poultry litter (PL) biochars affect the hydrology, microbial communities, N2O emissions, and nitrogen cycling in agricultural soils. The initial focus is on the impact of PL biochar on soil hydrology. PL from Perdue AgriRecycle, LLC (Seaford, Delaware) was used to produce biochars at pyrolysis temperatures from 300°C to 600°C. To explore the impact of these biochars on soil wettability, the PL biochars were mixed with a 30/40 Accusand in mass fractions from 0% to 100%. The water contact angle was then measured using a goniometer on these sand/biochar mixtures using the sessile drop method and a single layer of sample particles. The PL biochars produced at temperatures between 300°C to 400°C were hydrophobic, while those pyrolized at > 400°C were hydrophilic. Water contact angles for samples with 100% biochar varied systematically with pyrolysis temperature, decreasing from 101.12° to 20.57° as the pyrolysis temperature increased from 300 to 600°C. Even for small amounts of hydrophobic biochar added to the hydrophilic sand, the contact angle of the mixture was altered: for sand/biochar mixtures containing only 2% hydrophobic PL biochar by weight, the contact angle of the mixture increased from ~ 8° (0% biochar) to 20° (2% biochar). For higher mass fractions, the impact of hydrophobic PL biochar on the sand/mixture contact angle was more dramatic: for a sand/biochar mixture with 15% PL biochar, the contact angle was 40.12°. Water drop penetration tests were also performed on these samples, and results were consistent with contact angles measured with the sessile drop method. To further explore the cause of the varying contact angle with pyrolysis temperature, the PL biochars were vigorously rinsed with deionized water or heated for 24 hours at 105°C, and the contact angle measurements repeated. Both rinsing and heating samples rendered hydrophobic PL biochar hydrophilic. Rinsate samples were analyzed for total organic carbon and with GC-MS. These data suggest that bio-oils produced during slow-pyrolysis at temperatures < 400°C condensed on biochar and caused hydrophobicity. These bio-oils could be removed through vigorous washing with deionized water or heating to 105°C. The implication of these changes in water contact angle from PL biochar addition on water retention relationships for soil and on water distribution within pores will be discussed.

Yi, S. C.; Witt, B.; Guo, M.; Chiu, P.; Imhoff, P. T.

2012-12-01

293

Capillary electrophoresis of natural products.  

PubMed

Capillary electrophoresis (CE) and micellar electrokinetic chromatography were used for the separation of widely different compounds from natural materials including antibiotics, humic substances, flavonoids, isoflavonoids, illicit drugs, coumarins, alkaloids, steroids, Chinese herbal preparations, nicotine, caffeine, amphetamines, toxins such as aflatoxins B1, B2, G1, G2, mycotoxins, heptapeptide toxins and others, ephedrine compounds, mineral elements, and natural compounds in biological samples. A discussion of sample extraction and clean-up and the advantages of using CE is also presented. PMID:9456058

Issaq, H J

1997-11-01

294

Capillary electrophoresis systems and methods  

DOEpatents

An embodiment of the invention is directed to a capillary electrophoresis apparatus comprising a plurality of separation micro-channels. A sample loading channel communicates with each of the plurality of separation channels. A driver circuit comprising a plurality of electrodes is configured to induce an electric field across each of the plurality of separation channels sufficient to cause analytes in the samples to migrate along each of the channels. The system further comprises a plurality of detectors configured to detect the analytes.

Dorairaj, Rathissh (Hillsboro, OR); Keynton, Robert S. (Louisville, KY); Roussel, Thomas J. (Louisville, KY); Crain, Mark M. (Georgetown, IN); Jackson, Douglas J. (New Albany, IN); Walsh, Kevin M. (Louisville, KY); Naber, John F. (Goshen, KY); Baldwin, Richard P. (Louisville, KY); Franco, Danielle B. (Mount Washington, KY)

2011-08-02

295

Ultrastructure of cerebellar capillary hemangioblastoma  

Microsoft Academic Search

Large pinocytic vacuolar bodies (megalopinocytic vesicles) containing electron-dense granulo-fibrillary material, not previously described in micro-vascular endothelium of brain tumors, were observed in endothelial cells of all five cases of cerebellar hemangioblastoma studied ultrastructurally. They were present in 23% of a total of 132 capillary profiles studied. Some were prominent and aggregated to occupy a large portion of the endothelial cytoplasm.

K.-L. Ho

1986-01-01

296

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

297

Fluid Delivery System For Capillary Electrophoretic Applications.  

DOEpatents

An automated electrophoretic system is disclosed. The system employs a capillary cartridge having a plurality of capillary tubes. The cartridge has a first array of capillary ends projecting from one side of a plate. The first array of capillary ends are spaced apart in substantially the same manner as the wells of a microtitre tray of standard size. This allows one to simultaneously perform capillary electrophoresis on samples present in each of the wells of the tray. The system includes a stacked, dual carrousel arrangement to eliminate cross-contamination resulting from reuse of the same buffer tray on consecutive executions from electrophoresis. The system also has a gel delivery module containing a gel syringe/a stepper motor or a high pressure chamber with a pump to quickly and uniformly deliver gel through the capillary tubes. The system further includes a multi-wavelength beam generator to generate a laser beam which produces a beam with a wide range of wavelengths. An off-line capillary reconditioner thoroughly cleans a capillary cartridge to enable simultaneous execution of electrophoresis with another capillary cartridge. The streamlined nature of the off-line capillary reconditioner offers the advantage of increased system throughput with a minimal increase in system cost.

Li, Qingbo (State College, PA); Liu, Changsheng (State College, PA); Kane, Thomas E. (State College, PA); Kernan, John R. (Loganton, PA); Sonnenschein, Bernard (Brooklyn, NY); Sharer, Michael V. (Tyrone, PA)

2002-04-23

298

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

299

Design and fabrication of blood plasma separation PMMA chip using capillary phenomenon  

Microsoft Academic Search

In this study, a microdevice driven by capillary action has been developed for the high-throughput on-chip separation of plasma from a drop of blood. The microdevice is composed of an array of 2 ?m deep and 2 ?m wide PMMA (polymethylmethacrylate) channels. This PMMA microfluidic device is fabricated by hot embossing and thermal bonding from a Si master mold. The

H. Sakamoto; R. Hatsuda; K. Miyamura; S. Sugiyama

2010-01-01

300

Exercise Training Improves Insulin-Mediated Capillary Recruitment in Association With Glucose Uptake in Rat Hindlimb  

Microsoft Academic Search

Exercise training is considered to be beneficial in the treatment and prevention of insulin insensitivity, and much of the effect occurs in muscle. We have recently shown that capillary recruitment by insulin in vivo is associated with and may facilitate insulin action to increase muscle glucose uptake. In the present study, we examined the effect of 14 days of voluntary

S. Rattigan; Michelle G. Wallis; Joanne M. Youd; Michael G. Clark

2001-01-01

301

Capillary pumped loop body heat exchanger  

NASA Technical Reports Server (NTRS)

A capillary pumped loop for transferring heat from one body part to another body part, the capillary pumped loop comprising a capillary evaporator for vaporizing a liquid refrigerant by absorbing heat from a warm body part, a condenser for turning a vaporized refrigerant into a liquid by transferring heat from the vaporized liquid to a cool body part, a first tube section connecting an output port of the capillary evaporator to an input of the condenser, and a second tube section connecting an output of the condenser to an input port of the capillary evaporator. A wick may be provided within the condenser. A pump may be provided between the second tube section and the input port of the capillary evaporator. Additionally, an esternal heat source or heat sink may be utilized.

Swanson, Theodore D. (Inventor); Wren, deceased, Paul (Inventor)

1998-01-01

302

Understanding disintegrant action by visualization.  

PubMed

The aim of this study was to utilize high-speed video imaging for understanding the disintegrability of compacts and disintegrant action upon wetting. High-speed video imaging was used to visualize the disintegration of compacts and effect of wetting on free disintegrant particles. Acquired images were processed using MATLAB, and changes in the compact area and instantaneous motion of compacted particles on contact with water were analyzed. The capillary action of compacts was also determined for various disintegrants. Finally, the breakdown behavior of compacts prepared with selected disintegrants was analyzed at different compression forces to evaluate recovery of compaction strain. Water-insoluble inert diluent, dicalcium phosphate, was used as a comparator. The results from this visualization study provided an in-depth understanding of the disintegrant behavior of free and compacted disintegrant particles upon wetting. The mechanisms of swelling, capillary action, disruption of particle-particle bonds and strain recovery were successfully monitored by video imaging. The disintegration of compacts containing crospovidone appeared to be less influenced by swelling or wicking action. The influence of compression force on the disintegration of selected disintegrants confirmed that strain recovery is the dominant mechanism for the disintegrant action of crospovidone. PMID:22422140

Desai, Parind Mahendrakumar; Liew, Celine Valeria; Heng, Paul Wan Sia

2012-06-01

303

Transmission of slow highly charged ions through glass capillaries: Role of the capillary shape  

NASA Astrophysics Data System (ADS)

Comparison of the transmission of 27-keV Ar9+ ions through insulating funnel- and conical-shaped glass capillaries of outlet diameters of ˜22 ?m is reported. Beam intensities of 1, 5, and 10 pA were injected into both capillaries. Transmission at the untilted angle of 0° was measured as well as at a tilt angle of ˜0.5° for the funnel capillary and a tilt angle of ˜1.1° for the conical capillary. For the funnel capillary, blocking of transmission was observed, whereas, the transmission was continuous for the conical capillary. These measurements suggest that conical-shaped capillaries have transport properties that are different than funnel-shaped capillaries for slow highly charged ions.

Zhou, C. L.; Simon, M.; Ikeda, T.; Guillous, S.; Iskandar, W.; Méry, A.; Rangama, J.; Lebius, H.; Benyagoub, A.; Grygiel, C.; Müller, A.; Döbeli, M.; Tanis, J. A.; Cassimi, A.

2013-11-01

304

Heuristic approach to capillary pressures averaging  

SciTech Connect

Several methods are available to average capillary pressure curves. Among these are the J-curve and regression equations of the wetting-fluid saturation in porosity and permeability (capillary pressure held constant). While the regression equation seem completely empiric, the J-curve method seems to be theoretically sound due to its expression based on a relation between the average capillary radius and the permeability-porosity ratio. An analysis is given of each of these methods.

Coca, B.P.

1980-10-01

305

Wettability Tests of Polymer Films and Fabrics and Determination of Their Surface Energy by Contact-Angle Methods.  

National Technical Information Service (NTIS)

In this research, wettability testing was performed for nylon-6 and polyethylene films and ultra-high molecular weight polyethylene woven fabrics to examine the effects of surface atmospheric plasma treatment.

D. Pappas C. Copeland R. Jensen

2007-01-01

306

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

307

Monitoring nitrotyrosinylation of a synthetic peptide by capillary zone electrophoresis.  

PubMed

Proteins may be nitrated on tyrosyl residues (nitrotyrosinylated) by the action of reactive nitrogen species in inflamed tissues. Capillary electrophoresis was used to monitor this reaction in a model system with tetranitromethane as the nitrotyrosinylating reagent and a synthetic pentapeptide containing one tyrosine as the target molecule. The reaction was readily followed by capillary electrophoresis performed at pH 8 and, using an absorption wavelength of 436 nm, the signature spectral characteristics of the nitrotyrosinylated peptide were verified on-line. The peak appearance time for the nitrotyrosinylated peptide was more than 1 min longer than that of the starting material and a single main product was observed in contrast to the case when peroxynitrite was used as the nitrotyrosinylating reagent. Capillary electrophoresis appears to be a convenient method for the optimization of nitrotyrosinylation, examination of reaction inhibitors, and for studies of the consequences of nitrotyrosinylation, e.g., for antibody binding and for the function of the target protein or peptide. PMID:10499345

Bakhøj, A; Heegaard, N H

1999-09-01

308

On the fine structure of arc-capillaries: true a.v. anastomoses or sphincter capillaries?  

Microsoft Academic Search

The arc-capillaries represent vessels of the terminal bed; they are not true arterio-venous anastomoses. They exhibit a typical capillary structure of their wall. The existence of smooth muscle cells and modified smooth muscle cells, such as epitheloid cells, cannot be demonstrated. Likewise, a specific activation by nerves does not exist. The arc-capillaries differ from the net-capillaries neither in the structure

Rosmarie Leiderer; Frithjof Hammersen

1990-01-01

309

Capillaroscopy and the measurement of capillary pressure  

PubMed Central

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

Shore, Angela C

2000-01-01

310

Transient studies of capillary-induced flow  

NASA Technical Reports Server (NTRS)

This paper presents the numerical and experimental results of a study performed on the transient rise of fluid in a capillary tube. The capillary tube problem provides an excellent mechanism from which to launch an investigation into the transient flow of a fluid in a porous wick structure where capillary forces must balance both adverse gravitational effects and frictional losses. For the study, a capillary tube, initially charged with a small volume of water, was lowered into a pool of water. The behavior of the column of fluid during the transient that followed as more water entered the tube from the pool was both numerically and experimentally studied.

Reagan, M. K.; Bowman, W. J.

1993-01-01

311

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

312

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

313

Multimode dynamics of a liquid drop over an inclined surface with a wettability gradient.  

PubMed

A liquid drop placed over a solid surface with a wettability gradient self-propels to minimize its surface energy. It can also climb an inclined plane if the applied gradient strength is high enough. We investigate the motion of liquid drops over an inclined gradient surface using a unique 3D computational technique. The technique combines diffuse interface in a smoothed particle hydrodynamics simulation to study the internal fluid structure and the contact line dynamics. Simulation results reveal that drop motion is dependent on its volume, surface inclination, and the strength of the wettability gradient. It has been demonstrated that, depending on these parameters, a drop can experience upward or downward motion or can remain stationary on the inclined plane. Finally, drop mobility maps which give an idea about the regimes of uphill and downhill movement of a drop over gradient surfaces have been proposed. PMID:20481583

Das, A K; Das, P K

2010-06-15

314

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

PubMed

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

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

2009-12-01

315

Wettability control by laser texturing process generating localized gold nanoparticles on polymeric thin films.  

PubMed

In this work a new approach is introduced for surface properties control by laser texturing process. By UV laser irradiation, we are able to control the surface wettability of a chitosan polymeric film in which is introduced a chloroauric acid salt by immersion. Specifically the UV irradiation is responsible for the creation of gold nanoparticles at the irradiated surface of the polymeric film. This photolytic process allows us to localize and design accurately surface patterns and moreover to tune metallic particle size in the range of nanoscale. After the characterization of our gold textured surfaces by atomic force and scanning electron microscopies, we demonstrate the link between wettability surface properties and gold nanoparticles size. The experimental results indicate the influence of the laser intensity, the irradiation time and the polymer film thickness (by increasing the gold concentration) on the gold nanoparticle density and size. PMID:22905535

Spano, F; Castellano, A; Massaro, A; Fragouli, D; Cingolani, R; Athanassiou, A

2012-06-01

316

Correlation between sol-gel reactivity and wettability of silica films deposited on stainless steel  

NASA Astrophysics Data System (ADS)

Sol-gel silica films were deposited on 316L and 409 stainless steel substrates in order to investigate their wettability properties. These films were deposited by dip-coating varying some parameters of the sol-gel process, including the acid used in the synthesis, its concentration, and the heat treatment temperature. Water and oil contact angles were measured on the surfaces and discussed regarding the physico-chemical and morphological properties of the prepared films. The findings shown in this work allow correlating the wettability behavior of silica coatings with the sol-gel reactivity of sols prepared using various amounts of nitric acid. It was observed that the more reactive the silica sol, the more hydrophilic and oleophilic the prepared coating. The presence in the films of alkoxy residues due to an incomplete condensation reaction could decrease both the polar and dispersive components of the coating surface energy, respectively responsible for water and oil wetting.

Houmard, M.; Nunes, E. H. M.; Vasconcelos, D. C. L.; Berthomé, G.; Joud, J.-C.; Langlet, M.; Vasconcelos, W. L.

2014-01-01

317

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

318

Electromigration dispersion in Capillary Electrophoresis  

PubMed Central

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

Chen, Zhen; Ghosal, Sandip

2012-01-01

319

Capillary instability in nanowire geometries.  

PubMed

In this study, we present atomistic simulations and theoretical analyses that reveal a capillary instability that is intrinsic to wetting geometries characteristic of the vapor-liquid-solid mechanism for nanowire growth. The analysis establishes a transition between axisymmetric and tilted wetting configurations that occurs when the triple line geometry satisfies Young's force-balance condition. The intrinsic nature of the instability is anticipated to be linked to the phenomenon of nanowire kinking in response to changes in environmental conditions, such that the current results may have broad implications for the design of experimental strategies for controlled growth of crystalline nanowires with complex geometries. PMID:24842073

Frolov, Timofey; Carter, W Craig; Asta, Mark

2014-06-11

320

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

321

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

Microsoft Academic Search

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

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

2010-01-01

322

Acid-etching andHydration Influence onDentin Roughness andWettability  

Microsoft Academic Search

Adhesion ofrestorative andprotective materials to dentin isanimportant requirement foroperative andpre- ventive dentistry. Wettability androughness aredentin sub- strate conditions thatarecritical toestablishing good adhesion. Thisstudy examined superficial anddeepdentin forvariations inwatercontact angle measurements and roughness forpolished, etched, dehydrated, andrehydrated states. Superficial anddeepdentin disks from6non-carious third molarswereprepared forAFM (Atomic Force Microscope) observation, roughness measurement, andcon- tactangle measurements following specific treatments: hydrated andpolished, etched (10%H3PO4),

J. I. Rosales; G. W. Marshall; S. J. Marshall; L. G. Watanabe; M. Toledanol; M. A. Cabrerizo

323

Improvement of wettability and drop impact reliability by Al addition in SnAgCu solder  

Microsoft Academic Search

SnAgCu solder is most popular solder composition system in the package industry. Therefore, SnAgCu solder has been studied by many researchers to improve its properties. In this study, we ran tests to verify the effect of Al additive metal in SnAgCu solder in term of wettability and drop impact reliability. The test solder compositions were Sn1.0Ag0.5Cu solder (Ref. solder) and

Y. W. Lee; I. H. Kim; E. S. Kim; J. H. Lee; J. T. Moon

2010-01-01

324

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

SciTech Connect

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

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

2008-01-01

325

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

Microsoft Academic Search

Vacuum brazing studies have been performed on molybdenum and TZM (0.5Ti-0.08Zr-Mo). Wettability tests have been conducted for nineteen braze metal filler alloys on molybdenum and thirty-two braze metal filler alloys on TZM over a wide range of temperatures. A wetting index, which is a function of contact angle and braze alloy contact area, was determined for each filler alloy at

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

1988-01-01

326

Addition of silver nanoparticles reduces the wettability of methacrylate and silorane-based composites.  

PubMed

Incorporation of silver nanoparticles into composite resins is recommended for their reported antibacterial properties, but this incorporation can affect the wettability of such materials. Therefore, this study evaluated the effect of nano-silver addition to silorane-based and methacrylate-based composites on their contact angle. Nano-silver particles were added to Z250 (methacrylate-based) and P90 (silorane-based) composites at 0.5% and 1% by weight. The control group had no additions. SEM-EDX analysis was performed to confirm the homogeneity of the nano-silver distribution. Seventy-two composite discs were prepared and standardized to the identical surface roughness values, and then distributed randomly into 6 groups containing 12 samples each (N = 12). Two random samples from each group were observed by atomic force microscopy. Distilled water contact angle measurements were performed for the wettability measurement. Two-way ANOVA, followed by the Tukey-HSD test, with a significance level of 5%, were used for data analysis. It was observed that wettability was significantly different between the composites (p = 0.0001), and that the addition of nano-silver caused a significant reduction in the contact angle (p = 0.0001). Wettability varied depending on the concentration of the nano silver (p = 0.008). Silorane-based composites have a higher contact angle than methacrylate-based composites. Within the limitations of this study, it can be concluded that the addition of 0.5% nano-silver particles to the composites caused a decrease in the contact angle of water. PMID:23184163

Kasraei, Shahin; Azarsina, Mohadese

2012-01-01

327

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

328

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

329

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.

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

2013-01-01

330

A Photoresponsive Wettability Switch Based on a Dimethylamino Calix[4]arene.  

PubMed

A photoreversible switch based on a photoresponsive host-guest system consisting of dimethylamino calix[4]arene L and 4-(phenylazo)benzoic acid (O) is reported. The host L exhibited selective binding and release of O on UV and visible irradiation at 450 and 365?nm, respectively. Moreover, the photoresponsive host-guest complex was applied as a photocontrolled wettability switch on a functional micro/nanostructured silicon surface, and is thus promising for applications in sensors and microfluidic devices. PMID:24820202

Zhang, Xiaoyan; Zhao, Haiyang; Tian, Demei; Deng, Hongtao; Li, Haibing

2014-07-21

331

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

332

Structure, electrical, mechanical and wettability of quenched lead-free solder alloys  

Microsoft Academic Search

The experimental results obtained from the double bridge method, Vickers microhardness tester and dynamic resonance technique are used to evaluate the electrical resistivity, hardness, internal friction and elastic properties of binary, ternary and quaternary tin based lead-free solder alloys. In addition, structure and wettability of these solder alloys have been studied and analyzed. The quenched Sn91Zn9 Bi1Cu2 lead-free solder alloy

Mustafa Kamal; M. S. Meikhail; Abu Bakr El-bediwi; El-said Gouda

2005-01-01

333

CO2 laser modification of the wettability characteristics of a magnesia partially stabilized zirconia bioceramic  

Microsoft Academic Search

This paper describes the utilization of a 3 kW continuous wave CO2 laser to modify the wettability characteristics of the magnesia partially stabilized zirconia (MgO-PSZ) bioceramic and analyses the changes in the physical characteristics of the MgO-PSZ surface following the CO2 laser interaction. The measurement with a set of test liquids revealed that CO2 laser surface treatment of the MgO-PSZ

L. Hao; J. Lawrence

2003-01-01

334

Metal oxide-based nanoparticles: revealing their potential to enhance oil recovery in different wettability systems  

NASA Astrophysics Data System (ADS)

This paper presents systematic studies of hydrophilic metal oxide nanoparticles (NPs) dispersed in brine intended to reveal their potential to enhance oil recovery (EOR) in various rock wettability systems. The stability in suspension (nanofluid) of the NPs has been identified as a key factor related to their use as an EOR agent. Experimental techniques have been developed for nanofluid stability using three coupled methods: direct visual observation, surface conductivity and particle size measurements. The use of a dispersant has been investigated and has been shown to successfully improve metal oxide nanofluid stability as a function of its concentration. The dispersant alters the nanofluid properties, i.e. surface conductivity, pH and particle size distribution. A two-phase coreflood experiment was conducted by injecting the stable nanofluids as a tertiary process (nano-EOR) through core plugs with various wettabilities ranging from water-wet to oil-wet. The combination of metal oxide nanofluid and dispersant improved the oil recovery to a greater extent than either silica-based nanofluid or dispersant alone in all wettability systems. The contact angle, interfacial tension (IFT) and effluent were also measured. It was observed that metal oxide-based nanofluids altered the quartz plates to become more water-wet, and the results are consistent with those of the coreflood experiment. The particle adsorption during the transport process was identified from effluent analysis. The presence of NPs and dispersant reduced the IFT, but its reduction is sufficient to yield significant additional oil recovery. Hence, wettability alteration plays a dominant role in the oil displacement mechanism using nano-EOR.

Hendraningrat, Luky; Torsæter, Ole

2014-03-01

335

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

Microsoft Academic Search

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

Petr Ustohal; Fritz Stauffer; Themistocles Dracos

1998-01-01

336

Rapidly switched wettability of titania films deposited by dc magnetron sputtering  

NASA Astrophysics Data System (ADS)

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

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

2008-08-01

337

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

PubMed Central

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

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

2005-01-01

338

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

339

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

SciTech Connect

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

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

1988-01-01

340

Substrate material affects wettability of surfaces coated and sintered with silica nanoparticles  

NASA Astrophysics Data System (ADS)

Silica nanoparticles coating and sintering is a widely-used approach for creating hydrophobic and superhydrophobic surfaces. The role of substrate material in this process, however, has not been thoroughly investigated. In this work, the role of substrate material is examined by measuring surface wettability of three different substrate materials (glass, polyimide and copper) under systematically varied conditions. These surfaces are modulated from hydrophilic (water contact angle (WCA) < 90°) to superhydrophobic (WCA > 150°) by coating and sintering silica nanoparticles, followed by assembling a layer of fluorine compound. Static WCA characterization shows that surface wettability is not solely dependent on the concentration of the coating colloidal, but is also on the substrate material. In particular, copper substrate exhibits a larger WCA than glass and polyimide substrates. Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS) and Atomic Force Microscopy (AFM) characterizations show that the substrate material-dependent wettability is attributed to thermal-induced nanostructures on the copper surface, which contributes to the hierarchical micro-/nano- topography. This finding is important for designing hydrophobic/superhydrophobic surfaces comprised of different materials, especially those that would experience thermal cycles in surface functionalization and subsequent use.

Wei, Kang; Zeng, Hansong; Zhao, Yi

2013-05-01

341

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

PubMed

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 omega-terminated alkanethiolates on gold were used, allowing correlation of byssal plaque spreading with a single surface characteristic--wettability. The present results were inconsistent with those from previous studies, in that there was a positive correlation between plaque size and surface wettability; a trend which is not explained by conventional wetting theory for a three-phase system. A recent extension to wetting theory with regard to hydrophilic proteins is discussed and the results of settlement assays are used to attempt reconciliation of these results with those of similar previous studies and, also, with recent data presented for the spreading of Ulva linza spore adhesive. PMID:16849215

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

2006-02-22

342

Improving the wettability of 2024 aluminium alloy by means of cold plasma treatment  

NASA Astrophysics Data System (ADS)

Aluminium alloys are heavily used to manufacture structural parts in the aeronautic industry because of its lightness and its corrosion resistance. These alloys are successfully used in other industrial fields too, such as railway, automotive and naval industries. The need to contrast the severe use conditions and the heavy stresses developing in aeronautic field implies to protect the surfaces of the structures in aluminium alloy by any deterioration. To preserve by deterioration, it is necessary to make aluminium more suitable to be coated by protective paint. In the aeronautic industry, a complex and critical process is used in order to enhance both wettability and adhesive properties of aluminium alloy surfaces. Cold plasma treatment represents an efficient, clean and economic alternative to activate aluminium surfaces. The present work deals with air cold plasma treatment of 2024 aluminium alloy surfaces. The influence of dc electrical discharge cold plasma parameters on wettability of 2024 aluminium alloy surfaces has been studied. A set of process variables (voltage, time and air flow rate) has been identified and used to conduct some experimental tests on the basis of design of experiment (DOE) techniques. The experimental results show that the proposed plasma process may considerably increase aluminium alloy wettability. These results represent the first step in trying to optimise the aluminium adhesion by means of this non-conventional manufacturing process.

Polini, W.; Sorrentino, L.

2003-05-01

343

Effects of wettability and pore-level displacement on hydrocarbon trapping  

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

344

Wettability control of BeO surfaces by alpha-irradiation-induced nuclear transmutation  

NASA Astrophysics Data System (ADS)

A simple method to control the wettability of BeO surfaces is developed on the base of alpha irradiation. In this research, BeO disks were irradiated with an alpha beam under conditions of ?25 MeV in alpha particle energy and ?315 nA/cm2 in beam current density. After the alpha irradiation, changes in morphology and chemical composition of BeO surfaces were analyzed using a field emission scanning electron microscopy and X-ray photoelectron spectroscopy. The wettability of pristine and alpha-irradiated BeO surfaces was analyzed by measuring water contact angles (CAs). The result of analysis indicated that C and F atoms were produced by the alpha irradiation. 12C atoms were mainly produced by (?, n) nuclear reaction when 9Be atoms collide with energetic alpha particles. On the other hand, 19F atoms were mostly created by (?, n) reaction and following ?+ decay when 16O atoms collide with alpha particles. Moreover, CF2 functional groups, which provide hydrophobic property, were formed by the combination of produced C and F atoms. The amount of CF2 functional groups produced on the surface increased as the fluence increased while no significant change in the surface roughness was observed. Accordingly, the CA of alpha-irradiated BeO surfaces gradually increased as the fluence increased. In conclusion, the wettability of BeO surfaces could be easily and precisely controlled by the alpha irradiation, from hydrophilicity to hydrophobicity.

Lee, Eun Je; Hur, Min Goo; Kong, Young Bae; Son, Jeong Mun; Park, Yong Dae; Park, Jeong Hoon; Yang, Seung Dae

2014-08-01

345

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

346

Cryogenic Capillary Screen Heat Entrapment  

NASA Technical Reports Server (NTRS)

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 sub-cooled 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 LN2 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, "200x1400" and "325x2300", both with Twill Dutch Weave. Upon consideration of both the water and LN2 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.; Stathman, G.

2007-01-01

347

Capillary versus venous bedside blood glucose estimations  

Microsoft Academic Search

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

R Boyd; B Leigh; P Stuart

2005-01-01

348

Capillary pressures - examples of their use  

Microsoft Academic Search

Capillary pressures can be useful in many different ways, including (1) regional mapping, (2) reservoir comparison, (3) choosing downdip well locations from a tight oil-stained dry hole, and (4) choosing updip well locations from a porous oil-stained dry hole. Regional mapping - Four regional Ordovician Red River maps, based on capillary pressure data, were constructed for the western flank of

1988-01-01

349

Capillary transport in mortars and concrete  

Microsoft Academic Search

Results are presented of a study concerning capillary transport of water in concretes and mortars as a function of water\\/cement ratio, sand size distribution, and curing. Our studies indicate that the capillary sorption (1) of water in concrete exhibits a complex time dependence. At early times, of the order of one hour, the total water uptake increased with the t12

Nicos S. Martys; Chiara F. Ferraris

1997-01-01

350

Capillary Movement in Granular Beds in Microgravity  

NASA Technical Reports Server (NTRS)

Understanding the dynamics of capillary flow through unsaturated porous media is very important for the development of an effective water and nutrient delivery system for growing plants in microgravity and chemical engineering applications. Experiments were conducted on the Space Shuttle during the STS-63 mission using three experimental cuvettes called "Capillary Testbed-M." These experiments studied the effect of bead diameter on capillary flow by comparing the capillary flow in three different granular beds. It was observed that the speed of water propagation in the granular bed consisting of 1.5 mm diameter particles was less than that in the bed consisting of 1.0 mm. diameter particles. Such results contradict the existing theory of capillary water propagation in granular beds. It was found also that in microgravity water propagates independently in adjacent layers of a layered granular bed .

Yendler, Boris S.; Bula, Ray J.; Kliss, Mark (Technical Monitor)

1996-01-01

351

Labial capillary microscopy in systemic sclerosis.  

PubMed Central

OBJECTIVES--To investigate whether in vivo capillary microscopy of the lower lip mucosa can be used to assess microvascular disease in systemic sclerosis. METHODS--Thirteen patients with systemic sclerosis and 11 healthy control subjects were studied by conventional nailfold capillary microscopy and labial capillaroscopy. The following parameters were analysed: loop length; loop width (maximum distance between the arteriolar and venular limbs); loop density (number of capillaries/mm2); venular plexus visibility; megacapillaries; and the architectural arrangement of the capillary network. RESULTS--A typical 'scleroderma pattern' at the nailfold was observed in 12 of 13 (92%) patients with systemic sclerosis. Labial capillaroscopy showed a different morphological pattern of microangiopathy. A diffuse architectural derangement of the capillary network was the most striking abnormality in 12 (92%) patients. Labial capillaries in the patients with systemic sclerosis were shorter (mean (SD) loop length 133 (32.2) microns) than in healthy controls (211 (48.4) microns) and showed an increased loop width (41.7 (13.1) v 27.6 (5.5) microns in controls. The loop density was 10.5 (4.6) capillaries/mm2 in patients with systemic sclerosis and 9 (1.7) capillaries/mm2 in controls. Labial capillaroscopy in patients with systemic sclerosis did not provide definite evidence of enlarged capillaries or avascular areas, or both, even where such abnormalities were clearly evident at the nailfold. CONCLUSIONS--This study shows that labial capillary microscopy is a simple, non-invasive technique which allows a careful morphological assessment of the mucosal microcirculation. Labial capillaroscopy in patients with systemic sclerosis showed significant microvascular changes with respect to the controls. The results of labial and nailfold capillaroscopy are not superimposable, even if some common findings, such as architectural derangement, are present. Images

Grassi, W; Core, P; Carlino, G; Blasetti, P; Cervini, M

1993-01-01

352

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

PubMed Central

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

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

2011-01-01

353

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

354

About Mass Transfer in Capillaries of Biological Systems under Influence of Vibrations  

NASA Astrophysics Data System (ADS)

Vibrations accompany the flight of the manned spacecraft both at a stage of a orbital injection to an orbit, and during long flights (as noise), rendering undesirable physiological influence on crew, reducing serviceability and creating constant discomfort. The report represents attempt to predict a state of the cosmonaut in conditions of influence of vibrations for the period of start and stay in Space, being based on researches of mass transfer processes in capillary systems. For this purpose the original researches on heat and mass transfer processes with evaporation of liquids in capillary - porous structures in conditions of vibration actions and changes of a direction of action of gravitation are generalized. Report demonstrates the existence of modes at which increased or lowered mass transfer is achieved on border of separation "liquid - gas". The possible mechanism of influence of vibrations on evaporation of a liquid in capillaries is examined. The magnitudes of frequencies and amplitudes are submitted at which minimax characteristics are observed. The opportunity of application of the developed mathematical model of heat and mass transfer in capillary - porous structures to forecasting influence of vibrations for biological processes in capillaries of alive essences is analyzed. Such approach is justified on the mechanical nature of harmful influence of vibrations on an organism of the person. In addition the range of vibration frequencies which arise during space flights, corresponds to own resonant frequencies of a human body and his separate organs. Comparison of these resonant frequencies of a body of the person (5-80 Hertz) with vibration frequencies of optimum modes of heat and mass transfer in capillary - porous structures (20-40 Hertz) is shown their ranges of coverage. It gives the basis to assume existence of similar effects in capillaries of human body. It is supposed, that the difficulty of breath, change of a rhythm of breath, the subsequent weariness under vibration action are attributable to infringements of normal mass transfer between the inhaled air and blood. The opportunity of use of the received laws is discussed for assessment of influence of gravitational fields on intensity mass transfer in capillaries of biosystems also.

Prisniakov, K.

355

Schemes for the fragmentation and merging of droplets resting on a solid substrate using a patterned wettability gradient.  

PubMed

A methodology has been proposed for the breakup and joining of water drops over a solid surface by varying its wettability gradient. A computational scheme using diffuse interface based smoothed particle hydrodynamics has been employed to simulate the droplet dynamics as the proof of the concept. For both the joining and breakup of drops, Y shaped patterns with the same or different wettability gradient along its different arms have been proposed. The breakup of a drop at the junction of the Y joint may be achieved if it is subjected to pulling forces along both of the branch arms. The pulling force can be brought into existence by providing an appropriate wettability gradient along the branches. By a proper selection of the branch orientation and the wettability gradient along them, it is possible to break a drop into two droplets of equal or unequal size. It has also been demonstrated that a drop can be broken into three small droplets by a specially designed four junction pattern of wettability on the solid surface. A Y junction has also been used for the merger of two drops. For this, two water drops placed at the end of the two branches are made to move toward the junction due to the gradient of contact angle. At the junction, they collide and merge into a single drop. A scheme has also been described where a combination of Y patterns can be exploited to generate a multitude of drops of different size. PMID:20873727

Das, A K; Das, P K

2010-10-19

356

Preparation and characterization of gradient wettability surface depending on controlling Cu(OH)2 nanoribbon arrays growth on copper substrate  

NASA Astrophysics Data System (ADS)

Gradient wettability surface was prepared on copper substrate via a facile alkali assistant surface oxidation technique. It was based on the control of cupric hydroxide (Cu(OH)2) nanoribbon arrays growth from the upper part to lower part along the vertically placed copper substrate in an aqueous solution of NaOH and (NH4)2S2O8. Thus the gradient wettability functionalized Cu(OH)2 nanoribbon arrays were directly fabricated on copper substrate by varying the immersing time of different positions along the substrate surface. By using a relative dilute NaOH solution (0.75 mol/L) and (NH4)2S2O8 solution (0.03 mol/L), and regulating dropping speed, the surface gradient wettability changing from the original contact angle of copper substrate (90.5°) to surperhydrophilicity (3.0°) was prepared. The surface fabricated on copper substrate may keep its gradient wetting property after immersed in water bath at 100 °C for 10 h. The water contact angle measurement (CA), Scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were employed to analyze the wettability, morphologies, crystal structure, and surface chemical compositions of the Cu(OH)2 nanoribbon arrays on copper substrate. This research is expected to be significant in providing a new strategy for the preparation of novel gradient wettability material with potential industrial applications on copper substrate.

Huang, Ziheng; Zhang, Jiaoru; Cheng, Jiang; Xu, Shouping; Pi, Pihui; Cai, Zhiqi; Wen, Xiufang; Yang, Zhuoru

2012-10-01

357

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

SciTech Connect

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

Abbas Firoozabadi

2003-12-01

358

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

Microsoft Academic Search

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

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

359

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

PubMed

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

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

2011-05-17

360

Instability and dewetting of evaporating thin water films on partially and completely wettable substrates  

NASA Astrophysics Data System (ADS)

Stability, dynamics and dewetting of thin (<100 nm) evaporating water films on partially and completely wettable substrates are studied based on numerical solutions of the nonlinear thin film equation, as well as by simplified semianalytical approaches. The instability and rupture of aqueous films are engendered by the hydrophobic attraction, whereas the net van der Waals force is repulsive for aqueous films on most substrates. An evaporating aqueous film on a partially wettable surface thins uniformly to a critical thickness, and then spontaneously dewets the substrate by the formation of growing holes. Complete nonlinear simulations as well as the linear analyses are used to predict the most important, experimentally accessible characteristics of the instability such as the length scale and time scale of the instability and the mean film thickness at the instant of rupture. Curiously, in contrast to nonthinning films, the number density of holes decreases slightly with increased strength and range of hydrophobic attraction, and also with decreased strength of LW repulsion, even though both of these factors promote the macroscopic nonwettability. The rate of evaporation has the most significant influence on the length scale, ?~Eq, where the exponent, q lies in a narrow range from -0.17 to about -0.26, depending on the rate of evaporation and the critical thickness. Thin aqueous films on completely wettable (free energy per unit area is positive) surfaces are also unstable when the free energy does not decrease monotonically with the film thickness. Simulations show that instability in such cases leads to the formation of quasiequilibrium microscopic ``islands'' or ``pancakes'' made up of largely flat thin and thick films.

Padmakar, A. S.; Kargupta, Kajari; Sharma, Ashutosh

1999-01-01

361

Investigation into the photo-induced change in wettability of hydrophobized TiO 2 films  

NASA Astrophysics Data System (ADS)

The photo-induced change in wettability of hydrophobized TiO 2 films has been investigated for steel coated with acidic TiO 2 nanosols containing varying concentrations of dispersed nanocrystalline titania, such as Degussa P25. The photo-induced change in wettability was evaluated by measuring the time-dependent drop of water contact angle (WCA) after samples had been soaked in either n-octyltriethoxysilane (OTS) or decanoic acid (DA). TiO 2 films treated in this way exhibit superhydrophobic behaviour, with WCA greater than 160°. After radiation with UV (black light), the superhydrophobic properties are transformed into superhydrophilic properties, with WCA of almost 0°. As P25 content and layer thickness increase, high rates of photo-induced change are found, but a moderate calcination regime is required. On the other hand, hardness and E modulus pass through a maximum at 25 wt% P25, so that a P25 content between 25 and 50 wt% is the optimum for practical uses. With such stable coatings, wettability can be controlled over a wide range, and the switch between hydrophobic and hydrophilic states can be carried out repeatedly when DA is used as the hydrophobizing agent. Use of a low calcination temperature (450 °C) for the intermediate annealing of the single layers in multilayer coatings and a short final sintering step at a relatively high temperature (e.g. 630 °C for 10 min) allow the preparation of relatively thin TiO 2 films on steel with a high photoactivity.

Risse, Gunter; Matys, Sabine; Böttcher, Horst

2008-07-01

362

Wettability patterning for high-rate, pumpless fluid transport on open, non-planar microfluidic platforms.  

PubMed

Surface tension driven transport of liquids on open substrates offers an enabling tool for open micro total analysis systems that are becoming increasingly popular for low-cost biomedical diagnostic devices. The present study uses a facile wettability patterning method to produce open microfluidic tracks that - due to their shape, surface texture and chemistry - are capable of transporting a wide range of liquid volumes (~1-500 ?L) on-chip, overcoming viscous and other opposing forces (e.g., gravity) at the pertinent length scales. Small volumes are handled as individual droplets, while larger volumes require repeated droplet transport. The concept is developed and demonstrated with coatings based on TiO2 filler particles, which, when present in adequate (~80 wt.%) quantities within a hydrophobic fluoroacrylic polymer matrix, form composites that are intrinsically superhydrophobic. Such composite coatings become superhydrophilic upon exposure to UV light (390 nm). A commercial laser printer-based photo-masking approach is used on the coating for spatially selective wettability conversion from superhydrophobic to superhydrophilic. Carefully designed wedge-patterned surface tension confined tracks on the open-air devices move liquid on them without power input, even when acting against gravity. Simple designs of wettability patterning are used on versatile substrates (e.g., metals, polymers, paper) to demonstrate complex droplet handling tasks, e.g., merging, splitting and metered dispensing, some of which occur in 3-D geometries. Fluid transport rates of up to 350 ?L s(-1) are attained. Applicability of the design on metal substrates allows these devices to be used also for other microscale engineering applications, e.g., water management in fuel cells. PMID:24622962

Ghosh, Aritra; Ganguly, Ranjan; Schutzius, Thomas M; Megaridis, Constantine M

2014-05-01

363

?-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

364

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

Microsoft Academic Search

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

Christian W. Klampfl; Markus Himmelsbach; Wolfgang Buchberger

365

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

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

366

Wettability of a glass surface in the presence of two nonionic surfactant mixtures.  

PubMed

Measurements of the advancing contact angle (theta) were carried out for aqueous solution of p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycol), Triton X-100 (TX100), and Triton X-165 (TX165) mixtures on glass. The obtained results indicate that the wettability of glass depends on the concentration and composition of the surfactant mixture. The relationship between the contact angle and concentration suggests that the lowest wettability corresponds to the concentration of TX100 and TX165 and their mixture near the critical micelle concentration (CMC). The minimum of the dependence between the contact angle and composition of the mixtures for each concentration at a monomer mole fraction of TX100, alpha, equals 0.2 and 0.4 points to synergism in the wettability of the glass surface. In contrast to the results of Zisman ( Zisman, W. A. In Contact Angle, Wettability and Adhesion; Gould, R. F., Ed.; Advances in Chemistry Series 43; American Chemical Society Washington, DC, 1964; p 1 ) there was no linear dependence between cos theta and the surface tension of aqueous solutions of TX100 and TX165 mixtures for all studied systems, but a linear dependence exists between the adhesional tension and surface tension for glass, practically, in the whole concentration range of surfactants studied, the slopes of which are positive in the range of 0.43-0.67. These positive slopes indicate that the interactions between the water molecules and glass surface might be stronger than those between the surface and surfactant molecules. So, the surface excess of surfactant concentration at the glass-water interface is probably negative, and the possibility for surfactant to adsorb at the glass/water film-water interface is higher than that at the glass-water interface. This conclusion is confirmed by the values of the work of adhesion of "pure" surfactants, aqueous solutions of surfactants, and aqueous solutions of their mixtures to the glass surface and by the negative values of glass-water interfacial tension determined from the Young equation in the range of surfactant concentrations corresponding to their unsaturated monolayer at the water-air interface. PMID:18572957

Szymczyk, Katarzyna; Ja?czuk, Bronis?aw

2008-08-01

367

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

368

Photo-induced wettability of TiO2 film with Au buffer layer  

NASA Astrophysics Data System (ADS)

The effect of thickness of Au buffer layer (15-25 nm) between TiO2 film and substrate on the wettability of TiO2 films is reported. TiO2 films grown on Au buffer layer have a higher contact angle of 96-;100° as compared to 47.6o for the film grown without buffer layer. The transition from hydrophobicity to hydrophilicity under UV irradiation occurs within 10 min. for the buffer layered films whereas it is almost 30 min. for the film grown without buffer layer. The enhanced photo induced hydrophilicity is shown to be surface energy driven.

Purkayastha, Debarun Dhar; Sangani, L. D. Varma; Krishna, M. Ghanashyam; Madhurima, V.

2014-04-01

369

Synthesis of ZnO nanoflowers and their wettabilities and photocatalytic properties.  

PubMed

By combing laser direct writing and hydrothermal growth, we demonstrate the growth of three-dimensional flowerlike ZnO nanostructures from aqueous solution. Our approach offers synthetic flexibility in controlling film architecture, coating texture and crystallite size. The wettability is studied by measurement of time-dependent contact angles in the as-grown samples. In addition, superior photocatalytic activity of the flowerlike ZnO nanostructures in the degradation of Rhodamine B is investigated as well. The influence factors and formation mechanism of the flowerlike ZnO nanostructures are also analyzed and discussed. PMID:20721234

Guo, Xiaodong; Zhao, Quanzhong; Li, Ruxin; Pan, Huaihai; Guo, Xiaoyang; Yin, Anyuan; Dai, Weilin

2010-08-16

370

Capillary Assisted Thermosyphon For Shipboard Electronics Cooling.  

National Technical Information Service (NTIS)

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

E. H. Larsen

2003-01-01

371

Suppressed conductometric capillary electrophoresis separation systems  

SciTech Connect

A tubular cation-exchange membrane is installed at the end of a 60-cm-long 75-[mu]m-bore fused-silica capillary. A static dilute acid regenerant solution surrounds the membranes that functions as a suppressor. With positive high voltage applied to the capillary inlet and the regenerant solution grounded, effective suppression of electrolytes such as solutions of alkalic metal borate, glycinate, or cyanide is observed. Electroosmotic flow carries the capillary effluent past the suppressor into a conductivity detection cell constituted by two platinum wires inserted through the wall of a poly(vinyl chloride) capillary. The system provides detection limits in the 10--20 [mu]g/L range for a variety of anions; a typical separation requires 15 min. Applicability to a variety of real samples is demonstrated. 26 refs., 10 figs.

Dasgupta, P.K.; Bao, L. (Texas Tech Univ., Lubbock (United States))

1993-04-15

372

Scintigraphy for Pulmonary Capillary Protein Leak.  

National Technical Information Service (NTIS)

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

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

1982-01-01

373

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...

374

Numerical Simulation of Evaporating Capillary Jets.  

National Technical Information Service (NTIS)

A detailed numerical study of evaporating capillary jets is presented. The analysis is performed through use of a Galerkin finite element method with penalty formulation for solving the equations of motion and a flux method for tracking the free surface. ...

J. D. Zeda

1999-01-01

375

Capillary Pressure - Mac OS 10.7  

NSDL National Science Digital Library

Computer program for Mac OS 10.7 to illustrate the vascular control of capillary hydrostatic pressure. Possible simulations include arteriolar vasoconstriction and dilation, venous obstruction, hypotension, reflex vasoconstriction, etc.

2004-10-01

376

RF Liquid Measurement Of Capillary Tubes  

NASA Astrophysics Data System (ADS)

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

Poudyal, Bashudev; Mazzeo, Brian; Warnick, Karl

2009-10-01

377

ISS Update: Capillary Flow Experiments-2  

NASA Video Gallery

NASA Public Affairs Officer Kelly Humphries interviews Dr. Mark Weislogel, Principal Investigator for the Capillary Flow Experiments-2 (CFE), from the Portland State University in Oregon. The CFE i...

378

Scintigraphy for Pulmonary Capillary Protein Leak.  

National Technical Information Service (NTIS)

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

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

1983-01-01

379

Ablation Loss Studies for Capillary - Sustained Plasmas.  

National Technical Information Service (NTIS)

The most common discharge geometry used for efficiently generating plasma from stored electrical energy for gun ignition utilizes a capillary tube to contain, direct, and sustain the discharge. The plasma gas composition is determined by the air in the tu...

A. W. Williams R. A. Beyer

2006-01-01

380

A study of capillary flow from a pendant droplet  

Microsoft Academic Search

Surface tension driven capillary flow from a pendant droplet into a horizontal glass capillary is investigated in this paper.\\u000a Effect of the droplet surface on dynamic behavior of such capillary flow is examined and compared with surface tension driven\\u000a capillary flow from an infinite reservoir. In the experiment, capillaries of 300–700 ?m in diameter were used with glycerol–DI\\u000a water mixture solutions

Milad Radiom; Weng Kong Chan; Chun Yang

2009-01-01

381

Focusing neutrons with tapered capillary optics  

NASA Astrophysics Data System (ADS)

The transmission characteristics of radiation through hollow tapered capillaries may be described by expressions derived for straight capillaries but with a reduced critical angle. The size of the focused beam for recent transmission measurements through a tapered polycapillary focusing optic performed at various different wavelengths gives a measure of the reduced critical angle. We derive the transmission characteristics of the focusing lens from the measured data and compare these with the analytic results. A similar comparison is made for a polychromatic incident beam.

Mildner, D. F. R.; Chen-Mayer, H. H.; Gibson, W. M.

2002-12-01

382

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

383

Capillary Movement in Substrates in Microgravity  

NASA Technical Reports Server (NTRS)

A more complete understanding of the dynamics of capillary flow through an unsaturated porous medium would be useful for a number of space and terrestrial applications. Knowledge of capillary migration of liquids in granular beds in microgravity would significantly enhance the development and understanding of how a matrix based nutrient delivery system for the growth of plants would function in a microgravity environment. Thus, such information is of interest from the theoretical as well as practical point of view.

Bula, R. J.; Duffie, N. A.

1996-01-01

384

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

SciTech Connect

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

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

2007-09-30

385

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

PubMed

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

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

2013-06-13

386

Multiple capillary biochemical analyzer with barrier member  

DOEpatents

A multiple capillary biochemical analyzer is disclosed for sequencing DNA and performing other analyses, in which a set of capillaries extends from wells in a microtiter plate into a cuvette. In the cuvette the capillaries are held on fixed closely spaced centers by passing through a sandwich construction having a pair of metal shims which squeeze between them a rubber gasket, forming a leak proof seal for an interior chamber in which the capillary ends are positioned. Sheath fluid enters the chamber and entrains filament sample streams from the capillaries. The filament sample streams, and sheath fluid, flow through aligned holes in a barrier member spaced close to the capillary ends, into a collection chamber having a lower glass window. The filament streams are illuminated above the barrier member by a laser, causing them to fluoresce. The fluorescence is viewed end-on by a CCD camera chip located below the glass window. The arrangement ensures an equal optical path length from all fluorescing spots to the CCD chip and also blocks scattered fluorescence illumination, providing more uniform results and an improved signal-to-noise ratio. 12 figs.

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

1996-10-22

387

N2 and CO2 capillary breakthrough experiments on Opalinus Clay  

NASA Astrophysics Data System (ADS)

The aim of this project was to identify the critical capillary pressures on the drainage and the imbibition path for clay-rich rocks, at a burial depth of 1500 m (30 MPa confining pressure, 45°C). The experiments were performed on fully water-saturated sample plugs of 38 mm diameter and 5 to 20 mm length. The capillary breakthrough pressure was determined by step-wise increase of the differential pressure (drainage), the capillary snap-off pressure was determined from the final pressure difference at the end of a spontaneous imbibition phase. The confining pressure was kept constant throughout the experiment, which resulted in a continuous change of effective stress. The measurements were performed in a closed system and the pressure response was interpreted in terms of different flow mechanisms (diffusion-controlled vs. viscous flow). In total, four breakthrough experiments with N2 and five experiments with CO2 were conducted. Because of very low flow rates and high critical capillary pressures the experiments took rather long. In some cases the experiments were allowed to run for half a year (drainage experiments). Substantial differences were observed between gas breakthrough (drainage) and snap-off (imbibition) pressures. As expected, breakthrough pressures were always higher than the snap-off pressures. For three samples a pbreakthrough/psnap-off ratio of 1.6 to 1.9 was observed, for one sample a ratio of 4. A clear permeability-capillary pressure relationship could not be identified. Based on (omnidirectional) Hg-injection porosimetry results, and assuming perfectly water wet mineral surfaces, gas breakthrough pressures were predicted to occur at approximately 16 MPa for N2 and 5.7 MPa for CO2. The gas breakthrough experiments, however, produced different results. Even though a relatively homogeneous sample set was chosen, with permeability coefficients ranging between 1E-21 and 6E-21 m², the critical capillary breakthrough pressures for nitrogen ranged between 3.4 and 12.3 MPa and snap-off pressures from 0.5 to 6.4 MPa. The CO2 experiments yielded breakthrough pressures of 14.0 to 17.5 MPa and snap-off pressures of 3.5 to 10 MPa. No significant changes in single-phase water permeability coefficients before and after the gas breakthrough experiments were observed. In our contribution we will discuss the following points: 1. Gas fluxes occurring during gas breakthrough experiments may be extremely low. Therefore an unambigous identification of gas breakthrough is not always possible. Besides viscous or diffusive transport, dissolution of CO2 in the pore water may affect the observed pressure changes in the upstream and downstream compartments. All of these processes occur simultaneously and can only be partly discriminated. Gas fluxes detected during the diffusion-controlled flow regimes result in nominal effective gas permeability coefficients as low as 6E-25 m² to 7E-24m². 2. The application of purely capillary-controlled flow models may not be justified. o Gas breakthrough is controlled by effective stress, i.e. the opening of pores or small fissures. o Assumptions about wettability (completely water-wet mineral surfaces) may be incorrect.

Amann, Alexandra; Busch, Andreas; Krooss, Bernhard M.

2013-04-01

388

DNA Sequencing by Capillary Electrophoresis  

PubMed Central

Sequencing of human and other genomes has been at the center of interest in the biomedical field over the past several decades and is now leading toward an era of personalized medicine. During this time, DNA sequencing methods have evolved from the labor intensive slab gel electrophoresis, through automated multicapillary electrophoresis systems using fluorophore labeling with multispectral imaging, to the “next generation” technologies of cyclic array, hybridization based, nanopore and single molecule sequencing. Deciphering the genetic blueprint and follow-up confirmatory sequencing of Homo sapiens and other genomes was only possible by the advent of modern sequencing technologies that was a result of step by step advances with a contribution of academics, medical personnel and instrument companies. While next generation sequencing is moving ahead at break-neck speed, the multicapillary electrophoretic systems played an essential role in the sequencing of the Human Genome, the foundation of the field of genomics. In this prospective, we wish to overview the role of capillary electrophoresis in DNA sequencing based in part of several of our articles in this journal.

Karger, Barry L.; Guttman, Andras

2009-01-01

389

Neutron focusing using capillary optics  

NASA Astrophysics Data System (ADS)

Using the principle of multiple mirror reflection from smooth surfaces at small grazing angles, polycapillary fibers of narrow inner channels (diameter of a few micrometers) have been used to transport and bend slow neutron beams. Neutrons in the cold and thermal range have been focused to a small spot to produce significant gains ( ~ × 10) in intensity. We report studies of neutron transmission properties of individual capillaries, using cold and thermal neutrons at the CNRF (Cold Neutron Research Facility) of the NBSR (the 20 MW research reactor at the National Institute of Standards and Technology, USA). Several aspects of these properties are investigated, namely, the transmission as a function of bending curvature, of length of the fibers, and of composition of fiber materials. From these studies we obtain information on the critical angle of reflection, the reflectivity, and the roughness of the inner surface. We also report the characterization of the first prototype neutron lens constructed at the Kurchatov Institute in Moscow and show that a focal point of 1 mm has been achieved. Finally we discuss the design of a lens suitable for neutron absorption experiments at the end of a neutron guide.

Chen, H.; Mildner, D. F. R.; Downing, R. G.; Benenson, R. E.; Xiao, Q. F.; Sharov, V. A.

1994-05-01

390

Nonlinear waves in capillary electrophoresis  

PubMed Central

Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration ‘shocks’. In this paper we consider a simplified model consisting of a single sample ion and a background electrolyte consisting of a single co-ion and a counterion in the absence of any processes that might change the ionization states of the constituents. If the ionic diffusivities are assumed to be the same for all constituents the concentration of sample ion is shown to obey a one dimensional advection diffusion equation with a concentration dependent advection velocity. If the analyte concentration is sufficiently low in a suitable non-dimensional sense, Burgers’ equation is recovered, and thus, the time dependent problem is exactly solvable with arbitrary initial conditions. In the case of small diffusivity either a leading edge or trailing edge shock is formed depending on the electrophoretic mobility of the sample ion relative to the background ions. Analytical formulas are presented for the shape, width and migration velocity of the sample peak and it is shown that axial dispersion at long times may be characterized by an effective diffusivity that is exactly calculated. These results are consistent with known observations from physical and numerical simulation experiments.

Ghosal, Sandip; Chen, Zhen

2011-01-01

391

Capillary fracture of soft gels  

NASA Astrophysics Data System (ADS)

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?t3/4. 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.

Bostwick, Joshua B.; Daniels, Karen E.

2013-10-01

392

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

393

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

SciTech Connect

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

Al-Raoush, Riyadh I.; (Southern)

2009-07-31

394

Water wettability and zeta-potential of polystyrene surface modified by Ne or Na implantation  

SciTech Connect

A study has been made of the modification of the wettability and the surface potential of polystyrene by ion bombardment and implantation. Substrates used were polystyrene (PS) dishes. Ne bombardment and Na ion implantation were performed at energies of 50 and 150 keV with fluences between 1 {times} 10{sup 14} to 1 {times} 10{sup 17} ions/cm{sup 2}. The surface potential was examined by measurements of {zeta}-potential and the wettability was examined by the contact angle of water. The contact angle of water and the {zeta}-potential are found to change, depending on ion species and fluences. Two kinds of relationships between the contact angle of water and the {zeta}-potential are found, classified by region A and region B. From XPS results, region A means that PS surfaces modified by radiation effects of Ne-bombardment or Na-implantation have new functional groups and amorphous carbon. In region B, Na implanted PS surfaces with a high fluence show not only new functional groups and amorphous carbon but also Na atoms with chemical bonding states.

Nakao, Aiko; Suzuki, Yoshiaki; Iwaki, Masaya [Inst. of Physical and Chemical Research, Wako, Saitama (Japan). Div. of Surface Characterization] [Inst. of Physical and Chemical Research, Wako, Saitama (Japan). Div. of Surface Characterization

1998-01-15

395

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

NASA Astrophysics Data System (ADS)

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

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

2012-01-01

396

Electrochemical machining of super-hydrophobic Al surfaces and effect of processing parameters on wettability  

NASA Astrophysics Data System (ADS)

Super-hydrophobic aluminum (Al) surfaces were successfully fabricated via electrochemical machining in neutral NaClO3 electrolyte and subsequent fluoroalkylsilane (FAS) modification. The effects of the processing time, processing current density, and electrolyte concentration on the wettability, morphology, and roughness were studied. The surface morphology, chemical composition, and wettability of the Al surfaces were investigated using scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS), white-light interferometry, roughness measurements, X-ray diffraction (XRD), Fourier-transform infrared spectrometry (FTIR), and optical contact angle measurements. The results show that hierarchical rough structures and low surface energy films were present on the Al surfaces after electrochemical machining and FAS modification. The combination of the rough structures and the low surface energy materials plays a crucial role in achieving super-hydrophobicity. Compared with the anodic oxidation and chemical etching method, the method proposed in our work does not require strong acid or alkali, and causes less harm to the environment and operators but with high processing efficiency. The rough structures required by the super-hydrophobic surfaces were obtained at 30-s processing time and the best super-hydrophobicity with 164.6? water contact angle and 2? tilting angle was obtained at 360 s. The resulting super-hydrophobic Al surfaces have a long-time stability in air and an excellent resistance to corrosive liquids.

Song, Jin-long; Xu, Wen-ji; Liu, Xin; Lu, Yao; Sun, Jing

2012-09-01

397

Wettability conversion from superoleophobic to superhydrophilic on titania/single-walled carbon nanotube composite coatings.  

PubMed

Superoleophobic surfaces were demonstrated on perfluorosilane-rendered titania (TiO(2))/single-walled carbon nanotube (SWNT) composite coatings. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that SWNTs play a key role in the formation of overhanging structures and the nanoscale roughness on the coating surface, which compose the two critical morphologic factors for a superoleophobic surface. The wettability conversion from superoleophobic to superhydrophilic of the composite coatings was realized by the gradual decomposition of 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS) on the coating surface using UV irradiation. Contact angle measurement on both smooth TiO(2) surface and rough composite coating surface under different UV irradiation time revealed that the wetting behavior of the liquids on the composite coating surface passes from the Cassie to the Wenzel and finally to the inversed-Cassie regime. Different liquids show different irradiation time for the wetting state change. By controlling the UV irradiation dose, liquids with surface tension difference smaller than 5 mN/m can exist in completely converse wetting states on the same coating surface, that is, superphobic for one liquid while superphilic for another with lower surface tension. Mixed organic liquids with different surface tension can be completely separated through a coated grid using this wettability tuning technique. PMID:21732680

Zhang, Min; Zhang, Tao; Cui, Tianhong

2011-08-01

398

Development of a Freeze-Dried Fungal Wettable Powder Preparation Able to Biodegrade Chlorpyrifos on Vegetables  

PubMed Central

Continuous use of the pesticide chlorpyrifos has resulted in harmful contaminations in environment and species. Based on a chlorpyrifos-degrading fungus Cladosporium cladosporioides strain Hu-01 (collection number: CCTCC M 20711), a fungal wettable powder preparation was developed aiming to efficiently remove chlorpyrifos residues from vegetables. The formula was determined to be 11.0% of carboxymethyl cellulose-Na, 9.0% of polyethylene glycol 6000, 5.0% of primary alcohol ethoxylate, 2.5% of glycine, 5.0% of fucose, 27.5% of kaolin and 40% of freeze dried fungi by response surface methodology (RSM). The results of quality inspection indicated that the fungal preparation could reach manufacturing standards. Finally, the degradation of chlorpyrifos by this fungal preparation was determined on pre-harvest cabbage. Compared to the controls without fungal preparation, the degradation of chlorpyrifos on cabbages, which was sprayed with the fungal preparation, was up to 91% after 7 d. These results suggested this freeze-dried fungal wettable powder may possess potential for biodegradation of chlorpyrifos residues on vegetables and provide a potential strategy for food and environment safety against pesticide residues.

Chen, Shaohua; Xiao, Ying; Hu, Meiying; Zhong, Guohua

2014-01-01

399

Preparation of silica-on-titania patterns with a wettability contrast.  

PubMed

The preparation of patterned inorganic surfaces consisting of silica (SiO2) and titania (TiO2) is described. The approach is based on a combination of standard photolithography and plasma-enhanced chemical vapor deposition. Silicon wafers coated with a titania layer (40 nm) were patterned by use of a positive photoresist and then a thin silica layer (10-40 nm) was plasma-deposited. The photoresist was removed by decomposition at 800 degrees C. The inorganic patterned surfaces possessed excellent high-temperature resistance. Since the silica patches were effectively dehydroxylated during the thermal treatment, the patterns consisted of moderately hydrophobic (silica) and hydrophilic (titania) domains with a significant wettability contrast (40 degrees for water). The surface was further hydrophobized with a self-assembled monolayer of fluoroalkylsilane (FAS) and exposed to UV light. The FAS layer was locally oxidized on the TiO2 patches and the wettability contrast was maximized to 120 degrees (the highest possible value on smooth surfaces). PMID:15952824

Kanta, A; Sedev, R; Ralston, J

2005-06-21

400

Tolerance to systemic isotretinoin therapy in two patients using highly wettable contact lenses.  

PubMed

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, Ay?egül; Demirseren, D Deniz; Akoglu, Gulsen

2014-01-01

401

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

402

Non-capillary binding of colloidal particles to liquid interfaces  

NASA Astrophysics Data System (ADS)

We observe colloidal polystyrene particles binding reversibly to an oil-water interface through the combination of a repulsive electrostatic force and an attractive van der Waals force. Previously studied interactions of an aqueous colloidal particle and a liquid interface have generally fallen into two categories: 1) electrostatic repulsion indicated by the dependence on salt and 2) capillary adsorption where surface tension brings the particle in contact with both phases and is indicated by practically irreversible binding. With our technique of pushing individual colloidal particles towards a planar oil-water interface and observing their motion in three-dimensions with holographic microscopy we have observed both interactions. However, our observations indicate that under certain conditions the electrostatic repulsion, which is due to repulsive image charges, is weak enough for a particle to experience a van der Waals attraction while strong enough to prevent a particle from penetrating the interface and becoming bound through capillary action. We observe individual particles transition between repulsive and attractive interactions with the interface suggesting that these colloidal particles have a heterogeneous surface charge.

Kaz, David; McGorty, Ryan; Manoharan, Vinothan

2012-02-01

403

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

SciTech Connect

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. [Institute of Applied Physics RAS, Nizhny Novgorod (Russian Federation); Andreev, N. [Joint Institute for High Temperatures RAS, Moscow (Russian Federation); Moscow Institute of Physics and Technology (State University), Moscow (Russian Federation)

2012-09-15

404

Permanent gold nanoparticle coatings on polyelectrolyte multilayer modified capillaries for open-tubular capillary electrochromatography.  

PubMed

This paper reports on a new strategy to coat fused silica capillaries through ionic adsorption of gold nanoparticles (AuNPs) on a polyelectrolyte multilayer (PEM) modified capillary wall. The coating was constructed in situ by alternating rinses with positively charged poly(diallydimethylammonium chloride), negatively charged poly(sodium-4-styrenesulfonate), and positively charged AuNPs. After self-assembly of n-octadecanethiol onto the surface of AuNPs, the modified capillary was investigated as a new medium for the separation of neutral analytes and proteins in open-tubular capillary electrochromatography (OT-CEC). The surface coverage of the capillary wall was increased using the high density of AuNPs which were dynamically capped with 4-dimethylaminopyridine (DMAP). The chromatographic performance of the column coated with positively charged AuNPs was remarkably improved compared with a column modified with negatively charged AuNPs. The coating was robust over more than 810 runs in this study and also showed high stability against 0.01 M NaOH, 0.01 M HCl, and electrolyte concentrations up to 70 mM. The run-to-run, day-to-day, and capillary-to-capillary reproducibilities of electroosmotic flow were satisfying with relative standard deviation values of less than 1% in all cases. The AuNP-coated PEM modified capillary column not only showed good performance for neutral analytes but also was suitable for the analysis of both basic and acidic proteins. PMID:20850123

Qu, Qishu; Liu, Dengping; Mangelings, Debby; Yang, Chun; Hu, Xiaoya

2010-10-15

405

Gold nanoparticle-coated capillaries for protein and peptide analysis on open-tubular capillary electrochromatography.  

PubMed

We report a new method of immobilization of gold nanoparticles (AuNPs) on a fused-silica capillary through covalent binding. The resulting modified capillary was applied to electrophoretic systems to improve the efficiency of separation and the selectivity of selected solutes. The immobilization of AuNPs on the capillary wall was performed in a very simple and fast way without requiring heating. The surface features of an AuNP-coated capillary column were determined using the scanning electron microscopy. The chromatographic properties of AuNP-coated capillaries were investigated through variation of the buffer pH and separation voltage. Effective separations of synthetic peptides mixture were obtained on the AuNP-coated capillaries. The method shows a remarkable stability since it was reused about 900 times. The capacity factor was duplicated. Therefore, this modification is stable and can be applied to different separation purposes. A complex mixture of tryptic peptide fragments of HSA was analyzed in both the bare- and the AuNP-coated capillaries. Better electrophoretic peptide profile was observed when using the AuNP-coated capillary. PMID:22222978

Hamer, Mariana; Yone, Angel; Rezzano, Irene

2012-01-01

406

Slope wavenumber spectrum models of capillary and capillary-gravity waves  

NASA Astrophysics Data System (ADS)

Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using the dispersion relation of water surface waves, we derive the slope wavenumber spectrum models of capillary and capillary-gravity waves. Simultaneously, by using the slope wavenumber models, the dependence of the slope wavenumber spectrum on wind speed is analyzed using data obtained in an experiment which was performed in a laboratory wind wave tank. Generally speaking, the slope wavenumber spectra are influenced profoundly by the wind speed above water surface. The slope wavenumber spectrum increases with wind speed obviously and do not cross each other for different wind speeds. But, for the same wind speed, the slope wavenumber spectra are essentially identical, even though the capillary and capillary-gravity waves are excited at different times and locations. Furthermore, the slope wavenumber spectra obtained from the models agree quite well with experimental results as regards both the values and the shape of the curve.

Jia, Yongjun; Zhang, Jie; Wang, Yanfeng

2010-03-01

407

Capillary adhesion at the nanometer scale  

NASA Astrophysics Data System (ADS)

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 based on macroscopic theory for h down to ˜5 to 10 nm. 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 macroscopic 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 macroscopic theory are also identified. The surface tension term, as well as the meniscus shape, is accurately described by the macroscopic theory for h down to ˜1 nm, 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 component in the plane of the substrate is consistent with the capillary pressure predicted by the macroscopic theory (i.e., the Young-Laplace equation), but the normal pressure that determines the capillary force is always more positive than the continuum counterpart.

Cheng, Shengfeng; Robbins, Mark O.

2014-06-01

408

Critical Velocities in Open Capillary Flow  

NASA Technical Reports Server (NTRS)

This paper describes the proposed research program on open capillary flow and the preliminary work performed theoretically and in drop tower experiments. The work focuses on the fundamental physical understanding of the flow through capillary bound geometries, where the circumference of the cross section of the flow path contains free surfaces. Examples for such a flow configuration are capillary vanes in surface tension tanks, flow along edges and corners and flow through liquid bridges. The geometries may be classified by their cross section areas, wetted circumferences and the radii of curvature of the free surfaces. In the streaming float zone the flow path is bound by a free surface only. The ribbon vane is a model for vane types used in surface tension tanks, where a structure in proximity to the tank wall forms a capillary gap. A groove is used in heat pipes for the transportation of the condensed working fluid to the heat source and a wedge may occur in a spaceborne experiment where fluid has to be transported by the means of surface tension. The research objectives are the determination of the maximum volume flux, the observation of the free surfaces and the liquid flow inside the flow path as well as the evaluation of the limiting capillary wave speed. The restriction of the maximum volume flux is due to convective forces (flow velocity exceeding the capillary wave speed) and/or viscous forces, i.e. the viscous head loss along the flow path must be compensated by the capillary pressure due to the curved free surface. Exceeding the maximum volume flux leads to the choking of the flow path, thus the free surface collapses and.gas ingestion occurs at the outlet. The means are ground-based experimental work with plateau tanks and in a drop tower, a sounding rocket flight, and theoretical analysis with integral balances as well as full three dimensional CFD solutions for flow with free surfaces.

Dreyer, Michael; Langbein, Dieter; Rath, Hans J.

1996-01-01

409

Retardation of ice growth in glass capillaries: measurement of the critical capillary radius.  

PubMed

An experiment was designed to compare the freezing of an aqueous solution in glass microcapillaries and in thin films. The velocity dependence of the ice front propagation in glass capillaries with radii of 87.5 microm-1.5 microm was observed. A critical capillary radius r(0), corresponding to certain thermal conditions, was obtained, below which the ice growth inside the capillaries was retarded. This critical capillary radius is further related to lambda(0), the smallest wavelength used in the Mullins-Sekerka criterion for the instability analysis of bulk solidifications [Mullins and Sekerka, J. Appl. Phys. 35, 444 (1964)]. It was found that for the present hypothesis, r(0)=lambda(0)/4 gives good predictions. The relation between the propagation velocity (or cooling rate) and the critical radius (or pore size) is summarized in a chart for applications in capillary-porous media, such as in the freezing of biological tissues. PMID:14995462

Liu, Zhihong; Muldrew, Ken; Wan, Richard G; Elliott, Janet A W

2004-02-01

410

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

411

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

412

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, Élise

2013-12-01

413

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, Élise

2013-12-01

414

On the role of the viscosity ratio during low-capillary-number forced imbibition in porous media  

SciTech Connect

The role of the viscosity ratio K during forced imbibition in porous media is investigated theoretically using a new simulator, and experimentally based on displacements in model pore networks. Both theory and experiment show that K is an important parameter of microdisplacement in porous media, not only for intermediate and large capillary number values, but also for small values, say Ca < 10[sup [minus]6]. In the latter region the residual nonwetting saturation S[sub or], is virtually independent of Ca for K < 1, and increases weakly with decreasing Ca for K > 1. The unexpected result is that, even for very small values of Ca, S[sub or] decreases appreciably as K decreases, especially in the case of very good wettability. Simulations indicate that the effect of K on S[sub or] for low Ca values is enhanced as the contact angle decreases. The phenomenon is attributed to a synergistic effect between capillary microfingering and localized viscous forces. It must be emphasized that the velocity gradients which are created locally by the advance of a single meniscus, or of a wetting film, are sufficiently large to make viscous stresses important, even when the Ca value of the macroscopic flow is very low (say, of order 10[sup [minus]8]). A favorable viscosity ratio reduces the extent of capillary microfingering and thus increases the efficiency of microdisplacement, despite the fact that for Ca < [approximately]10[sup [minus]6] the viscous stresses are negligible on a macroscopic scale. Further work is needed to analyze the synergism between [kappa] and [theta][sub e] at low Ca values.

Vizika, O.; Avraam, D.G.; Payatakes, A.C. (Univ. of Patras (Greece). Dept. of Chemical Engineering ICE/HT-FORTH, Patras (Greece))

1994-07-01

415

Action Learning.  

ERIC Educational Resources Information Center

These four papers were presented at a symposium on action learning moderated by Lex Dilworth at the 1996 conference of the Academy of Human Resource Development. "Developing an Infrastructure for Individual and Organizational Change: Transfer of Learning from an Action Reflection Learning (ARL) Program" (ARL Inquiry) reports findings from a study…

1996

416

Capillary liquid chromatography using laser-based and mass spectrometric detection. [Capillary zone electrophoresis (CZE); micellar electrokinetic capillary kchromatography (MECC)  

SciTech Connect

In the years following the 1986 seminal paper (J. Chromatogr. Sci., 24, 347-352) describing modern capillary zone electrophoresis (CZE), the prominence of capillary electrokinetic separation techniques has grown. A related electrochromatographic technique is micellar electrokinetic capillary chromatography (MECC). This report presents a brief synopsis of research efforts during the current 3-year period. In addition to a description of analytical separations-based research, results of efforts to develop and expand spectrometric detection for the techniques is reviewed. Laser fluorometric detection schemes have been successfully advanced. Mass spectrometric research was less fruitful, largely owing to personnel limitations. A regenerable fiber optic sensor was developed that can be used to remotely monitor chemical carcinogens, etc. (DLC)

Sepaniak, M.J.; Cook, K.D.

1992-01-01

417

Electrical resistance of muscle capillary endothelium.  

PubMed

A recently developed technique for in vivo determination of the electrical resistance of vascular endothelium in microvessels was applied to the vessels in a thin frog muscle, m. cutaneus pectoris. The technique consists of injection of current via a glass micropipette into a capillary and measurement of the resulting intra- and extravascular potential profiles with another micropipette placed at various distances from the current source. The theory of Peskoff and Eisenberg (1974) was used to handle the problems arising from distributed extravascular resistances and was experimentally shown to describe the external field satisfactorily. With this extension of one-dimensional cable theory the specific electrical resistance of arterial microvessels was 33 omega cm2 and of venous capillaries 23 omega cm2. The "length constants" were 135 and 112 micrometers, respectively. If results from arterial and venous vessels are taken together, the ionic permeabilities at 20 degrees C were PNa = 3.9 X 10(-5) cm X s-1, PK = 5.7 X 10(-5) cm X s-1, PCl = 5.9 X 10(-5) cm X s-1 and PHCO3 = 3.4 X 10(-5) cm X s-1. These figures agree with figures for capillary permeability obtained in tracer experiments on whole muscle. The study bridges a gap between single capillary and whole organ techniques with the conclusion that the two different approaches lead to similar results in muscle capillaries. PMID:6601500

Olesen, S P; Crone, C

1983-04-01

418

Capillary flow in polymer microfluidic chips  

NASA Astrophysics Data System (ADS)

Disposable polymer microfluidic chips have been used more and more in miniaturized analytical devices. The surface of the polymers often needs to be treated to acquire specific properties. This study investigates the characteristics of capillary flow in three microfluidic chips under different surface conditions and the aim is to understand how the surface property could affect the capillary flow over the shelf life of the chips. The channel surfaces of polymer chips were treated using air plasma. The interface pattern and velocity were measured by a photographic technique and a micron Particle Imaging Velocimetry (MicroPIV) method. The glass chip could maintain a capillary flow velocity of around 3.0 mm/s and showed little reduction with time. The velocity agreed well with theory by Washburn. The PDMS chip surfaces could be easily modified and the capillary flow rate could reach 4 mm/s. However, the hydrophilicity decreased rapidly over time and was lost completely within a few hours. The polycarbonate chips need more powerful surface treatment. Once modified, the surface could sustain for much longer time. It took one month for the capillary flow velocity to decrease by 50%.

Zhu, Y.; Petkovic-Duran, K.

2007-12-01

419

Electrical resistance of muscle capillary endothelium.  

PubMed Central

A recently developed technique for in vivo determination of the electrical resistance of vascular endothelium in microvessels was applied to the vessels in a thin frog muscle, m. cutaneus pectoris. The technique consists of injection of current via a glass micropipette into a capillary and measurement of the resulting intra- and extravascular potential profiles with another micropipette placed at various distances from the current source. The theory of Peskoff and Eisenberg (1974) was used to handle the problems arising from distributed extravascular resistances and was experimentally shown to describe the external field satisfactorily. With this extension of one-dimensional cable theory the specific electrical resistance of arterial microvessels was 33 omega cm2 and of venous capillaries 23 omega cm2. The "length constants" were 135 and 112 micrometers, respectively. If results from arterial and venous vessels are taken together, the ionic permeabilities at 20 degrees C were PNa = 3.9 X 10(-5) cm X s-1, PK = 5.7 X 10(-5) cm X s-1, PCl = 5.9 X 10(-5) cm X s-1 and PHCO3 = 3.4 X 10(-5) cm X s-1. These figures agree with figures for capillary permeability obtained in tracer experiments on whole muscle. The study bridges a gap between single capillary and whole organ techniques with the conclusion that the two different approaches lead to similar results in muscle capillaries.

Olesen, S P; Crone, C

1983-01-01

420

Capillary gas chromatography of s-triazines.  

PubMed

In order to achieve better resolution and lower detection limits for s-triazines, glass capillary columns made of soft soda-lime glass and etched with gaseous hydrogen chloride have been introduced. Columns with non-polar (OV-101, SE-30) mixed (Carbowax 20M + SE-30) and polar stationary liquids (Carbowax 20M) were used. The thickness of the ultra-thin film columns was determined by weighing the capillaries before and after coating of the capillary with stationary phase and conditioning, and varied from 0.05 to 0.5 mum. From the capacity ratios of s-triazines and n-alkanes measured in sections of an originally long dynamically coated column after it had been cut into several equal parts, the constancy of the film thickness along the whole column was judged. The film thickness was not uniform and increased along the whole column. It was found that glass capillary columns with non-polar stationary phase are not very suitable for the analysis of s-triazine herbicides, as tailing occurs with some of them. Symmetrical peaks and the separation of 17 from 18 analysed s-triazines were achieved on glass capillary columns coated with Carbowax 20M. PMID:914938

Matisová, E; Krupcik, J

1977-11-11

421

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

Microsoft Academic Search

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

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

422

Tuning the wettability of calcite cubes by varying the sizes of the polystyrene nanoparticles attached to their surfaces  

Microsoft Academic Search

The wettability of calcite cubes was tuned by varying the sizes of the polystyrene nanoparticles attached to their surfaces via a dispersion polymerization. The products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersion spectrum (EDS) and Fourier transformation infrared spectrum (FTIR). The results showed that the hydrophobicity of the calcite cubes was enhanced with the increase

Yongjun He; Tanliang Li; Xiangyang Yu; Shiyong Zhao; Jianhua Lu; Jia He

2007-01-01

423

Carbon steel wettability characteristics enhancement for improved enamelling using a 1.2 kW high power diode laser  

Microsoft Academic Search

High-power diode laser (HPDL) surface treatment of a common engineering carbon steel (EN8) was found to effect significant changes to the wettability characteristics of the metal. These modifications have been investigated in terms of the changes in the surface roughness of the steel, the presence of any surface melting, the polar component of the steel surface energy and the relative

J. Lawrence; L. Li

2000-01-01

424

Wettability and interfacial reaction of alumina and zirconia by reactive silver-indium base alloy at mid-temperatures  

Microsoft Academic Search

The wettability of sintered alumina and sintered zirconia by silver-indium base alloy with small titanium additions (2, TiO and Ti2O, and those formed in the interface of the alloy on the zirconia are TiO and Ti2O.

X. M. Xue; J. T. Wang; Z. T. Sui

1993-01-01

425

Fine wettability control created by a photochemical combination method for inkjet printing on self-assembled monolayers.  

PubMed

Wettability tuning for organic solvents is demonstrated with the "combination method", a reversal of the conventional "cleavage method". Several advantages are inherent to this method: for example, the syntheses are simple, various surface-active groups can be used, and the reaction proceeds with a low-energy light source. The image shows the result after UV irradiation through a patterning mask. PMID:22252911

Tsuchiya, Youichi; Haraguchi, Shuichi; Ogawa, Masashi; Shiraki, Tomohiro; Kakimoto, Hidenobu; Gotou, Osamu; Yamada, Takeshi; Okumoto, Kenji; Nakatani, Shuhei; Sakanoue, Kei; Shinkai, Seiji

2012-02-14

426

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

427

Capillary electrochromatographic analysis of barbiturates in serum.  

PubMed

A capillary electrochromatographic method was developed for the separation of barbiturates. The separation was optimized in a 75 microm ID capillary, packed with 3-(1,8-naphthalimido)propyl-modified silyl silica gel (NAIP), studying the effect of buffer pH, buffer concentration, and mobile phase composition. Using an applied voltage of 20 kV and the short-end injection method (9 cm capillary effective length), the mobile phase of 1.0 mM citrate buffer (pH 5.0) containing 40% methanol provided the baseline separation of barbital, phenobarbital, secobarbital, and thiopental (internal standard) in less than 4.5 min. The method was successfully applied to the analysis of barbiturates in human serum. Under the optimal conditions, good repeatability and linearity were obtained in the range of 2.90-43.29 microg/mL for barbital, phenobarbital, and secobarbital. PMID:14981686

Ohyama, Kaname; Wada, Mitsuhiro; Lord, Gwyn A; Ohba, Yoshihito; Fujishita, Osamu; Nakashima, Kenichiro; Lim, Chang Kee; Kuroda, Naotaka

2004-02-01

428

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.

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

429

XUV Radiation Emitted by Capillary Pinching Discharge  

NASA Astrophysics Data System (ADS)

Fast capillary discharge in nitrogen is studied as a source of incoherent monochromatic radiation in "water window" wavelength range. Discharge system with current amplitude 13.5 kA and half period 140 ns was designed, realized and modeled. Strong spectral line at 2.88 nm corresponding to the quantum transition 1s2p?1s2 of helium -like nitrogen ions was detected. The initial pressure nitrogen in the alumina capillary was varied from 10 to 220 Pa. Peak value of the line intensity at about 50 Pa was found and proved by the computer modeling.

Vrbova, M.; Jancarek, A.; Vrba, P.; Nevrkla, M.; Kolar, P.

430

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

431

Capillary origami and superhydrophobic membrane surfaces  

NASA Astrophysics Data System (ADS)

Capillary origami uses surface tension to fold and shape solid films and membranes into three-dimensional structures. It uses the fact that solid surfaces, no matter how hydrophobic, will tend to adhere to and wrap around the surface of a liquid. In this work, we report that a superhydrophobic coating can be created, which can completely suppress wrapping as a contacting water droplet evaporates. We also show that using a wetting azeotropic solution of allyl alcohol, which penetrates the surface features, can enhance liquid adhesion and create more powerful Capillary Origami. These findings create the possibility