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Sample records for wettability capillary action

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

    SciTech Connect

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

    2006-02-01

    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.

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

    SciTech Connect

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

    2004-10-01

    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.

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

    SciTech Connect

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

    2006-12-08

    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.

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

    SciTech Connect

    Norman R. Morrow

    2004-05-01

    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.

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

    SciTech Connect

    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

    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.

  6. Silicon ribbon growth by a capillary action shaping technique

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

  7. The uniform capillary model for packed beds and particle wettability.

    PubMed

    Stevens, Nate; Ralston, John; Sedev, Rossen

    2009-09-01

    The distribution and movement of fluids in porous media are important in a variety of situations arising naturally and industrially (e.g., water migration in soils, oil recovery, chromatography, filtration and separation processes). Our specific interest is in deriving advancing and receding contact angles from capillary pressure measurements in packed beds of particles partially saturated with liquids. The simplest model of a porous medium treats the porous body as an equivalent uniform capillary giving rise to the same capillary pressure. Pressure measurements were performed successfully with advancing as well as receding liquids. For an advancing liquid front a measurement with a second liquid is needed to calibrate the equivalent capillary radius and obtain the advancing contact angle. For a receding liquid front--an additional determination of the amount of liquid trapped behind in smaller pores is required. The equivalent capillary radius is mainly determined by the porosity of the packed bed and is easily corrected to account for capillary retention. Only then can the receding contact angle be obtained reliably. This new methodology for contact angle measurement was validated with model systems and applied successfully to various real particulate systems. PMID:19486994

  8. Silicon ribbon growth by a capillary action shaping technique

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    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.

  9. Capillary, wettability and interfacial dynamics in polymer electrolyte fuel cells

    SciTech Connect

    Mukherjee, Partha P

    2009-01-01

    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.

  10. Direct determination of contact angles of model soils in comparison with wettability characterization by capillary rise

    NASA Astrophysics Data System (ADS)

    Ramírez-Flores, Juan Carlos; Bachmann, Jörg; Marmur, Abraham

    2010-03-01

    SummaryAn accurate method to determine contact angles (CA) of soils as a measure of water repellency is still missing. In the present research, we evaluated and compared different methods to determine the CA of dry soil samples. Experiments were made by using a set of porous materials (silt, sand and glass beads) with different levels of water repellency. The CAs were measured with the Capillary Rise Method ( ?CRM; liquid penetration into a 3-d system), the Wilhelmy plate method ( ?WPM; measurement of capillary forces acting on a plane sample) and the Sessile Drop Method ( ?SDM; optical CA analysis of drop contour on a plane sample). Results were compared with the CAs calculated from capillary rise in long vertical columns ( ?ECR), where liquid profiles of the final capillary rise of water and ethanol, respectively, were used to derive the contact angle under the assumed equilibrium conditions. The results showed the overestimation of the CA by using the well established bi-liquid CRM technique for porous materials, in particular for material with a low degree of water repellency (CA < 40°) and for the finer textured materials. In contrast, a variant of the Wilhelmy plate method, i.e. the cosine-averaged advancing CA and receding CA ( ?EWPM), as well as the Sessile Drop CA, ?SDM, were close to the ones of ?ECR. We concluded that ?EWPM and ?SDM are apparent CA, but nevertheless able to predict the impact of wettability on the final capillary rise which is affected by pore topology as well as by wettability.

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

    NASA Astrophysics Data System (ADS)

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

    2006-05-01

    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.

  12. Modelling the effect of pore structure and wetting angles on capillary rise in soils having different wettabilities

    NASA Astrophysics Data System (ADS)

    Czachor, Henryk

    2006-09-01

    SummaryCapillary rise in axis symmetrical sinusoidal capillary (SC) has been modelled. Analytical formula for meniscus radius, capillary pressure and meniscus rate in SC have been found. Capillary shape described by wall waviness highly influences all of them. The limit between wettability and repellency in such capillary is described by critical value of contact angle ?c which is related to the pore geometry by the equation ctg( ?c) = ?d2, where d2 - pore wall waviness. Kinetics of capillary rise in sinusoidal capillary has been determined by numerical integration of meniscus rate equation for a wide range of pore wall waviness and several values of contact angles. Application of Washburn theory to the data obtained from simulation gives the contact angle value much higher than the true one. In contrast, the obtained pore radius value is usually well correlated with capillary neck. However, in some cases a calculated radius can be even smaller. Above conclusions have been qualitatively confirmed by experiments performed on glass beads and soils. Contact angle measured on flat glass was 27.4°. The calculations concerning the data from capillary rise experiments on 90-1000 ?m fraction of glass powder and Washburn theory gave values ca. 80°. The contact angle values for peat soils and loamy sand have close values, which supports the opinion that non-cylindrical shape of soil pores highly influences both the wettability/repellency and the water flux in soils.

  13. Rapid retraction of microvolume aqueous plugs traveling in a wettable capillary

    NASA Astrophysics Data System (ADS)

    Kim, Jinho; O'Neill, John D.; Vunjak-Novakovic, Gordana

    2015-10-01

    We report a transport behavior—specifically, rapid retraction movement—of small (˜?L) deionized water plugs traveling in series within a small wettable tubular geometry. In this study, two water plugs separated by a certain distance in a dry cylindrical glass capillary were moved by positive pressure airflow applied at the tube inlet. As the plugs travel, a thin aqueous film is generated between the plugs as a result of the leading plug's aqueous deposition onto the inner surface of the tube. The leading plug continuously loses volume by film deposition onto the surface and eventually ruptures. Then, the lagging plug quickly travels the distance initially separating the two plugs (plug retraction). Our studies show that the rapid retraction of the lagging plug is caused by surface tension in addition to the positive pressure applied. Furthermore, the plug retraction speed is strongly affected by tube radius and the distance between the plugs.

  14. Influence of Wettability on Dense Nonaqueous Phase Liquid (DNAPL) Capillary Hysteresis Behavior and Relative Permeability in Saturated Porous Media

    NASA Astrophysics Data System (ADS)

    Ocarroll, D. M.; Polityka, C. A.; Phelan, T. J.; Abriola, L. M.

    2003-04-01

    Alhough it is commonly assumed that subsurface soils are completely water-wet, variations in wettability are likely in the contaminated subsurface. Dense nonaqueous phase liquids (DNAPLs) have often been released as part of acidic or basic mixtures containing surface active compounds. These mixtures can render subsurface soils intermediate to organic-wet. In addition natural soils have a variety of wetting characteristics. This works explores the effects of solid wettability on capillary pressure/saturation and relative permeability/saturation constitutive relationships for DNAPL/water systems. Tetrachloroethene (PCE) is used as a representative DNAPL in these experiments. A series of capillary pressure/saturation experiments and multistep column outflow experiments were conducted to estimate capillary retention and relative permeability functions for PCE in media with various wetting properties. Relative permeability/saturation parameters were quantified utilizing a multiphase flow simulator coupled with an inverse optimization routine. The optimization routine minimizes the square difference between experimental and simulated outflow by varying the constitutive parameters. Capillary pressure/saturation data, generated in small pressure cell experiments, facilitate independent verification of the retention functions fit to the multistep outflow experiments. Primary drainage, imbibition, and scanning curves are presented for water, intermediate and organic-wet F35/F50/F70/F110 sand. The utility of using Leverett scaling, in conjunction with independently measured contact angles, to scale primary drainage curves is assessed for these sands. Finally, results from the outflow experiments indicate that traditional capillary-based predictive models fail to capture observed relative permeability behavior at endpoint saturations.

  15. Influence of the heterogeneous wettability on capillary trapping in glass-beads monolayers: Comparison between experiments and the invasion percolation theory.

    PubMed

    Geistlinger, Helmut; Ataei-Dadavi, Iman

    2015-12-01

    We demonstrated that a change in the surface chemistry, i.e., a change from heterogeneous to homogeneous wettability, can dramatically influence capillary trapping, i.e., from significant trapping (?5%) to no trapping. Furthermore, the displacement process (water displaces air) in glass-beads monolayer with heterogeneous wettability shows (i) a heterogeneous morphology and a stochastic advancement of the interface in the highly ordered triangular structure, (ii) capillary trapping of a broad variety of gas clusters, notably large ganglia-like and network-like gas clusters, and (iii) a variation in the contact angle between 30° and 100°. In the second part of this paper, we compared the experimental results of capillary trapping for the monolayer that possesses a heterogeneous wettability with predictions from the invasion percolation theory and found excellent agreement, e.g., that the experimental cluster size distribution can be described by a universal power-law with an averaged exponent ?(exp)=2.06; that is a deviation of 5% from the theoretical value. This agreement indicates that capillary trapping within the 2D-monolayer is governed by the 3D critical exponent; therefore, the monolayer shows a trapping behavior similar to a 3D-porous media. We proposed an analytical approach to calculate the mass transfer rate constant using functional relationships predicted by percolation theory and compare this result with results derived from empirical relationships, which are often used for modelling the dissolution process of trapped non-wetting phases. PMID:26298285

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

    SciTech Connect

    Plug, W.J.; Mazumder, S.; Bruining, J.

    2008-12-15

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

  17. 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)

    Raeesi, Behrooz; Piri, Mohammad

    2009-10-01

    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.

  18. Silicon ribbon growth by a capillary action shaping technique

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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%.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  20. Capillary Action may Cool Systems and Precisely balance Chemical Reactions

    NASA Astrophysics Data System (ADS)

    Kriske, Richard

    2011-10-01

    It is well known that it takes no work for Water to rise in a Capillary tube against the force of Gravity. There is a precise balance in this system that resembles Robert Millikan's ``Oil Drop'' experiment, where mass was balanced against the electrostatic force. If at the top of the capillary tube there is evaporation, one can see that the system is cooled as another water molecule has room to move up the column. Furthermore, if the evaporation process can be controlled one photon at a time, a precise balance is created between a photon, and the height/mass of the column. If other molecules are place in the column, they can be moved up and down the column, in a chromatograph way, in a fairly precise manner, by controlling evaporation and molecular weight. If in addition to all of this, the interface of the solution against the walls of the column have Fermi levels, it can be seen as a very precise Electrochemical Device. In the situation of nanotubes, as opposed to trees and plants, these properties can be used to create measure environmental properties and to Balance Chemical Reactions. Forests, and Plants may cool themselves and their environment using this process, and using this process coupled with more energetic photons through photosynthesis.

  1. Effect of wettability on light oil steamflooding

    SciTech Connect

    Olsen, D.K.

    1991-12-01

    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.

  2. Effect of wettability on light oil steamflooding

    SciTech Connect

    Olsen, D.K.

    1991-12-01

    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.

  3. Wettability contrasts between fresh and weathered diesel fuels.

    PubMed

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

    2013-01-01

    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

  4. Doppler spectroscopy of blood in capillary plexus under the action of 40% glucose solution

    NASA Astrophysics Data System (ADS)

    Korolevich, A. N.; Yelshin, A.; Belsley, M.; Mota, M.

    2006-08-01

    The investigation of blood dynamical characteristics in the skin under the action of 40% glucose solution was performed in vivo by the laser Doppler technique. Experiments demonstrate that glucose solution affects significantly the blood perfusion and concentration. Qualitative explanation was made for observed perfusion dynamic effect in the skin dermis based on the following factors: tissue cells shrinkage and additional capillaries opening under osmotic stress. The size of glucose vesicle lens was measured under the skin by ultrasonography. The analysis of vesicle sizes monitoring leads to the conclusion that glucose lens spread, basically, along the skin than in the perpendicular to the skin surface direction. Obtained results show the significant anisotropic perturbation of the dynamic characteristics of blood in vascular plexus under the optical active solution influence that must be taken into consideration during optical clarification of biological tissues.

  5. Thin films, asphaltenes, and reservoir wettability

    SciTech Connect

    Kaminsky, R.; Bergeron, V.; Radke, C.J. |

    1993-04-01

    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 the oil and rock phases, asphaltene components in the crude oil adsorb irreversibly on the solid surface, changing it from water-wet to oil-wet. Conditions of wettability alteration can be found by performing adhesion tests, in which an oil droplet is brought into contact with a solid surface. Exceeding a critical capillary pressure destabilizes the film, causing spontaneous film rupture to a molecularly adsorbed layer and oil adhesion accompanied by pinning at the three-phase contact line. The authors conduct adhesion experiments similar to those of Buckley and Morrow and simultaneously examine the state of the underlying thin film using optical microscopy and microinterferometry. Aqueous thin films between an asphaltic Orcutt crude oil and glass surfaces are studied as a function of aqueous pH and salinity. For the first time, they prove experimentally that strongly water-wet to strongly oil-wet wettability alteration and contact-angle pinning occur when thick aqueous films thin to molecularly adsorbed films and when the oil phase contains asphaltene molecules.

  6. Wettability of graphene

    NASA Astrophysics Data System (ADS)

    Parobek, David; Liu, Haitao

    2015-09-01

    The discovery of graphene has renewed the interest in the wettability of graphitic materials. Although graphene and graphite are long believed to be hydrophobic, recent studies have challenged this long-held belief. In addition, the unique structure of graphene also enabled new avenues to manipulate their wetting properties. This review highlights recent studies in these research areas with a special focus on the following topics: (1) intrinsic wettability of graphene; (2) manipulate the wettability of graphene by surface engineering; (3) theoretical studies of water-graphene interaction; and (4) cleaning of graphene.

  7. The Measurement of Wettability

    ERIC Educational Resources Information Center

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

    1973-01-01

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

  8. Drying patterns of porous media containing wettability contrasts.

    PubMed

    Shokri, N; Or, D

    2013-02-01

    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

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

    NASA Astrophysics Data System (ADS)

    Kriske, Richard

    2012-02-01

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

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

    SciTech Connect

    Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

    2007-09-30

    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.

  11. Reversing Glass Wettability

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Smith, J. E., Jr.; Kaukler, W. F.

    1985-01-01

    Treatment reverses wettability of glassware: Liquids that normally wet glass no longer do, and those that do not wet glass are made to do so. Useful in research on container effects in nucleation and growth of secondary phase from solution. Treatment consists of spreading 3 percent (by weight) solution of silicone oil in hexane isomers over glass, drying in air, and curing at 300 degrees C in vacuum for one hour.

  12. Wettability of graphene.

    PubMed

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

    2013-04-10

    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

  13. 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 ...

  14. Wettability Modification of Nanomaterials by Low-Energy Electron Flux

    NASA Astrophysics Data System (ADS)

    Torchinsky, I.; Rosenman, G.

    2009-10-01

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

  15. Evaluation of Reservoir Wettability and its Effect on Oil Recovery

    SciTech Connect

    Buckley, Jill S.

    1999-07-01

    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.

  16. Distinctive Capillary Action by Micro-channels in Bone-like Templates can Enhance Recruitment of Cells for Restoration of Large Bony Defect.

    PubMed

    Oh, Daniel S; Koch, Alia; Eisig, Sidney; Kim, Sahng Gyoon; Kim, Yoon Hyuk; Kim, Do-Gyoon; Shim, Jae Hyuck

    2015-01-01

    Without an active, thriving cell population that is well-distributed and stably anchored to the inserted template, exceptional bone regeneration does not occur. With conventional templates, the absence of internal micro-channels results in the lack of cell infiltration, distribution, and inhabitance deep inside the templates. Hence, a highly porous and uniformly interconnected trabecular-bone-like template with micro-channels (biogenic microenvironment template; BMT) has been developed to address these obstacles. The novel BMT was created by innovative concepts (capillary action) and fabricated with a sponge-template coating technique. The BMT consists of several structural components: inter-connected primary-pores (300-400 µm) that mimic pores in trabecular bone, micro-channels (25-70 µm) within each trabecula, and nanopores (100-400 nm) on the surface to allow cells to anchor. Moreover, the BMT has been documented by mechanical test study to have similar mechanical strength properties to those of human trabecular bone (~3.8 MPa)(12). The BMT exhibited high absorption, retention, and habitation of cells throughout the bridge-shaped (?) templates (3 cm height and 4 cm length). The cells that were initially seeded into one end of the templates immediately mobilized to the other end (10 cm distance) by capillary action of the BMT on the cell media. After 4 hr, the cells homogenously occupied the entire BMT and exhibited normal cellular behavior. The capillary action accounted for the infiltration of the cells suspended in the media and the distribution (active migration) throughout the BMT. Having observed these capabilities of the BMT, we project that BMTs will absorb bone marrow cells, growth factors, and nutrients from the periphery under physiological conditions. The BMT may resolve current limitations via rapid infiltration, homogenous distribution and inhabitance of cells in large, volumetric templates to repair massive skeletal defects. PMID:26380953

  17. Distinctive Capillary Action by Micro-channels in Bone-like Templates can Enhance Recruitment of Cells for Restoration of Large Bony Defect

    PubMed Central

    Oh, Daniel S.; Koch, Alia; Eisig, Sidney; Kim, Sahng Gyoon; Kim, Yoon Hyuk; Kim, Do-Gyoon; Shim, Jae Hyuck

    2015-01-01

    Without an active, thriving cell population that is well-distributed and stably anchored to the inserted template, exceptional bone regeneration does not occur. With conventional templates, the absence of internal micro-channels results in the lack of cell infiltration, distribution, and inhabitance deep inside the templates. Hence, a highly porous and uniformly interconnected trabecular-bone-like template with micro-channels (biogenic microenvironment template; BMT) has been developed to address these obstacles. The novel BMT was created by innovative concepts (capillary action) and fabricated with a sponge-template coating technique. The BMT consists of several structural components: inter-connected primary-pores (300-400 µm) that mimic pores in trabecular bone, micro-channels (25-70 µm) within each trabecula, and nanopores (100-400 nm) on the surface to allow cells to anchor. Moreover, the BMT has been documented by mechanical test study to have similar mechanical strength properties to those of human trabecular bone (~3.8 MPa)12. The BMT exhibited high absorption, retention, and habitation of cells throughout the bridge-shaped (?) templates (3 cm height and 4 cm length). The cells that were initially seeded into one end of the templates immediately mobilized to the other end (10 cm distance) by capillary action of the BMT on the cell media. After 4 hr, the cells homogenously occupied the entire BMT and exhibited normal cellular behavior. The capillary action accounted for the infiltration of the cells suspended in the media and the distribution (active migration) throughout the BMT. Having observed these capabilities of the BMT, we project that BMTs will absorb bone marrow cells, growth factors, and nutrients from the periphery under physiological conditions. The BMT may resolve current limitations via rapid infiltration, homogenous distribution and inhabitance of cells in large, volumetric templates to repair massive skeletal defects. PMID:26380953

  18. Metallic surfaces with special wettability

    NASA Astrophysics Data System (ADS)

    Liu, Kesong; Jiang, Lei

    2011-03-01

    Metals are important and irreplaceable engineered materials in our society. Nature is a school for scientists and engineers, which has long served as a source of inspiration for humans. Inspired by nature, a variety of metallic surfaces with special wettability have been fabricated in recent years through the combination of surface micro- and nanostructures and chemical composition. These metallic surfaces with special wettability exhibit important applications in anti-corrosion, microfluidic systems, oil-water separation, liquid transportation, and other fields. Recent achievements in the fabrication and application of metallic surfaces with special wettability are presented in this review. The research prospects and directions of this field are also briefly addressed. We hope this review will be beneficial to expand the practical applications of metals and offer some inspirations to the researchers in the fields of engineering, biomedicine, and materials science.

  19. Quantitative evaluation of porous media wettability using NMR relaxometry.

    PubMed

    Fleury, M; Deflandre, F

    2003-01-01

    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

  20. Femtosecond laser controlled wettability of solid surfaces.

    PubMed

    Yong, Jiale; Chen, Feng; Yang, Qing; Hou, Xun

    2015-12-14

    Femtosecond laser microfabrication is emerging as a hot tool for controlling the wettability of solid surfaces. This paper introduces four typical aspects of femtosecond laser induced special wettability: superhydrophobicity, underwater superoleophobicity, anisotropic wettability, and smart wettability. The static properties are characterized by the contact angle measurement, while the dynamic features are investigated by the sliding behavior of a liquid droplet. Using different materials and machining methods results in different rough microstructures, patterns, and even chemistry on the solid substrates. So, various beautiful wettabilities can be realized because wettability is mainly dependent on the surface topography and chemical composition. The distinctions of the underlying formation mechanism of these wettabilities are also described in detail. PMID:26415826

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

    SciTech Connect

    Hu, W.

    1993-09-01

    This project is concerned with the new concept for coal surface wettability evaluation and modulation. The objective of the work is to study the fundamental surface chemistry features about the evaluation of the surface wettability of coal and pyrite and establish a new separation strategy which could contribute to the advanced coal-cleaning for premium fuel application. In the past quarter report, the capillary rise test results of three coal and mineral pyrite samples in distilled water, kerosene, and salt solution indicated that there are good agreements between the experimental observations and theoretical assumption. In this quarter, the further capillary rise tests were conducted for coal, pyrite and coal pyrite in distilled water, kerosene and benzene. The test results shown that surface wettability of coal, mineral pyrite, and coal pyrite have good correlation with the theoretical predictions.

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

    SciTech Connect

    Hu, Weibai

    1993-12-31

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

  3. Stabilizing Fluid-Fluid Displacements in Porous Media Through Wettability Alteration

    NASA Astrophysics Data System (ADS)

    Trojer, Mathias; Szulczewski, Michael L.; Juanes, Ruben

    2015-05-01

    We study experimentally how wettability impacts fluid-fluid-displacement patterns in granular media. We inject a low-viscosity fluid (air) into a thin bed of glass beads initially saturated with a more-viscous fluid (a water-glycerol mixture). Chemical treatment of glass surfaces allows us to control the wetting properties of the medium and modify the contact angle ? from 5° (drainage) to 120° (imbibition). We demonstrate that wettability exerts a powerful influence on the invasion morphology of unfavorable mobility displacements: increasing ? stabilizes fluid invasion into the granular pack at all capillary numbers. In particular, we report the striking observation of a stable radial displacement at low capillary numbers, whose origin lies on the cooperative nature of fluid invasion at the pore scale.

  4. Electron-induced wettability modification

    SciTech Connect

    Aronov, Daniel; Molotskii, Michel; Rosenman, Gil

    2007-07-15

    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.

  5. Electron-induced wettability modification

    NASA Astrophysics Data System (ADS)

    Aronov, Daniel; Molotskii, Michel; Rosenman, Gil

    2007-07-01

    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.

  6. Diagenetic and compositional controls of wettability in siliceous sedimentary rocks, Monterey Formation, California

    NASA Astrophysics Data System (ADS)

    Hill, Kristina M.

    Modified imbibition tests were performed on 69 subsurface samples from Monterey Formation reservoirs in the San Joaquin Valley to measure wettability variation as a result of composition and silica phase change. Contact angle tests were also performed on 6 chert samples from outcrop and 3 nearly pure mineral samples. Understanding wettability is important because it is a key factor in reservoir fluid distribution and movement, and its significance rises as porosity and permeability decrease and fluid interactions with reservoir grain surface area increase. Although the low permeability siliceous reservoirs of the Monterey Formation are economically important and prolific, a greater understanding of factors that alter their wettability will help better develop them. Imbibition results revealed a strong trend of decreased wettability to oil with increased detrital content in opal-CT phase samples. Opal-A phase samples exhibited less wettability to oil than both opal-CT and quartz phase samples of similar detrital content. Subsurface reservoir samples from 3 oil fields were crushed to eliminate the effect of capillary pressure and cleansed of hydrocarbons to eliminate wettability alterations by asphaltene, then pressed into discs of controlled density. Powder discs were tested for wettability by dispensing a controlled volume of water and motor oil onto the surface and measuring the time required for each fluid to imbibe into the sample. The syringe and software of a CAM101 tensiometer were used to control the amount of fluid dispensed onto each sample, and imbibition completion times were determined by high-speed photography for water drops; oil drop imbibition was significantly slower and imbibition was timed and determined visually. Contact angle of water and oil drops on polished chert and mineral sample surfaces was determined by image analysis and the Young-Laplace equation. Oil imbibition was significantly slower with increased detrital composition and faster with increased silica content in opal-CT and quartz phase samples, implying decreased wettability to oil with increased detrital (clay) content. However, contact angle tests showed that opal-CT is more wetting to oil with increased detritus and results for oil on quartz-phase samples were inconsistent between different proxies for detritus over their very small compositional range. Water contact angle trends also showed inconsistent wetting trends compared to imbibition tests. We believe this is because the small range in bulk detrital composition between the "pure" samples used in contact angle tests was close to analytical error and because small-scale spatial compositional variability may be significant enough to effect wettability. These experiments show that compositional variables significantly affect wettability, outweighing the effect of silica phase.

  7. Tunable wettability of microstructured polypyrrole films

    E-print Network

    Chang, Jean H

    2010-01-01

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

  8. Capillary-Driven Flow in Liquid Filaments Connecting Orthogonal Channels

    NASA Technical Reports Server (NTRS)

    Allen, Jeffrey S.

    2005-01-01

    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.

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

    PubMed

    Chen, Longquan; Bonaccurso, Elmar

    2014-08-01

    In this paper, we experimentally investigated the dynamic spreading of liquid drops on solid surfaces. Drop of glycerol water mixtures and pure water that have comparable surface tensions (62.3-72.8 mN/m) but different viscosities (1.0-60.1 cP) were used. The size of the drops was 0.5-1.2 mm. Solid surfaces with different lyophilic and lyophobic coatings (equilibrium contact angle ?(eq) of 0°-112°) were used to study the effect of surface wettability. We show that surface wettability and liquid viscosity influence wetting dynamics and affect either the coefficient or the exponent of the power law that describes the growth of the wetting radius. In the early inertial wetting regime, the coefficient of the wetting power law increases with surface wettability but decreases with liquid viscosity. In contrast, the exponent of the power law does only depend on surface wettability as also reported in literature. It was further found that surface wettability does not affect the duration of inertial wetting, whereas the viscosity of the liquid does. For low viscosity liquids, the duration of inertial wetting corresponds to the time of capillary wave propagation, which can be determined by Lamb's drop oscillation model for inviscid liquids. For relatively high viscosity liquids, the inertial wetting time increases with liquid viscosity, which may due to the viscous damping of the surface capillary waves. Furthermore, we observed a viscous wetting regime only on surfaces with an equilibrium contact angle ?(eq) smaller than a critical angle ?(c) depending on viscosity. A scaling analysis based on Navier-Stokes equations is presented at the end, and the predicted ?(c) matches with experimental observations without any additional fitting parameters. PMID:25215736

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

    SciTech Connect

    Hu, Weibai

    1993-12-01

    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 wettability is dependent on the carbon homologous series of alcohol, as shorter the carbon chain of the alcohol, the better surface wettability. The Hu`s evaluation of wettability of H{sub H2O}/H{sub methanol}, H{sub H2O}/H{sub ethanol}, and H{sub H2O}/H{sub propanol} for five samples are listed respectively in table 4, 5 and 6. It indicates that in the water/methanol, water/ethanol, and water/propanol system, Upper Freeport Coal is very little hydrophilicity, or better floatability than Coal Pyrite, it also can be seen that in these system, Pittsburgh No.8 Coal have a little hydrophilicity, or better floatability than Coal pyrite, it would mean that if Methanol, Ethanol, and Propanol are used as flotation collector, coal will be selectively separated from coal pyrite. This has been verified by our investigation elsewhere. The Hu`s evaluation of wettability of H{sub methanol}/H{sub kerosene} for five samples are listed in table 7. It is very interesting to note that the five samples have more methanol-philicity than kerosene. This is very useful for flotation reagents evaluation and selection in practice. The Hu`s evaluation of wettability of H{sub ethanol}/H{sub kerosene} for five samples are listed in table 8. It is indicated that ethanol also can be used as flotation collector. The Hu`s evaluation of wettability H{sub propanol}/H{sub kerosene} for five samples are listed in table 9. It shows that the five samples have lower propanol-philicity than kerosene.

  11. Influence of wettability on constitutive relations and its role in upscaling

    SciTech Connect

    Soll, W.E.; Gray, W.G.; Tompson, A.F.B.

    1998-07-01

    The lattice Boltzmann (LB) method is applied to simulating multifluid flow in porous media at sub-pore resolution to determine constitutive behaviors. The authors address the importance of the LB technique for identifying process based constitutive relationships, and demonstrate its application through analysis of the influence of wettability on interfacial areas and constitutive relationships. Porous media surface wettability is varied from uniformly strongly wetted by the resident fluid through strongly wetted by the displacing fluid. Spatially variable wettability is also demonstrated. Primary imbibition and drainage displacements are run, and interfacial areas (IFA) as a function of time are determined and compared. Results indicate that wettability is an important factor in displacement behavior and resulting interfacial area. Primary imbibition in a strongly wet material under capillary dominated flows produces film flow, resulting in high IFAs that decrease with increasing saturation and viscous forces. Primary drainage produces initially high IFA that decreases slightly with increasing saturation or pressure drop. Surfaces with spatially variable wetting can have a strong influence on resulting fluid distributions and fluid flow.

  12. Capillary penetration failure of blood suspensions.

    PubMed

    Zhou, Ronghui; Chang, Hsueh-Chia

    2005-07-15

    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

  13. Asymmetric Wettability Directs Leidenfrost Droplets

    SciTech Connect

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

    2014-01-01

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

  14. Nanofluid surface wettability through asymptotic contact angle.

    PubMed

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

    2011-03-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  16. Polymeric surfaces exhibiting photocatalytic activity and controlled anisotropic wettability

    NASA Astrophysics Data System (ADS)

    Anastasiadis, Spiros H.; Frysali, Melani A.; Papoutsakis, Lampros; Kenanakis, George; Stratakis, Emmanuel; Vamvakaki, Maria; Mountrichas, Grigoris; Pispas, Stergios

    2015-03-01

    In this work we focus on surfaces, which exhibit controlled, switchable wettability in response to one or more external stimuli as well as photocatalytic activity. For this we are inspired from nature to produce surfaces with a dual-scale hierarchical roughness and combine them with the appropriate inorganic and/or polymer coating. The combination of the hierarchical surface with a ZnO coating and a pH- or temperature-responsive polymer results in efficient photo-active properties as well as reversible superhydrophobic / superhydrophilic surfaces. Furthermore, we fabricate surfaces with unidirectional wettability variation. Overall, such complex surfaces require advanced design, combining hierarchically structured surfaces with suitable polymeric materials. Acknowledgment: This research was partially supported by the European Union (European Social Fund, ESF) and Greek national funds through the ``ARISTEIA II'' Action (SMART-SURF) of the Operational Programme ``Education and Lifelong Learning,'' NSRF 2007-2013, via the General Secretariat for Research & Technology, Ministry of Education and Religious Affairs, Greece.

  17. Capillary muscle

    PubMed Central

    Cohen, Caroline; Mouterde, Timothée; Quéré, David; Clanet, Christophe

    2015-01-01

    The contraction of a muscle generates a force that decreases when increasing the contraction velocity. This “hyperbolic” force–velocity relationship has been known since the seminal work of A. V. Hill in 1938 [Hill AV (1938) Proc R Soc Lond B Biol Sci 126(843):136–195]. Hill’s heuristic equation is still used, and the sliding-filament theory for the sarcomere [Huxley H, Hanson J (1954) Nature 173(4412):973–976; Huxley AF, Niedergerke R (1954) Nature 173(4412):971–973] suggested how its different parameters can be related to the molecular origin of the force generator [Huxley AF (1957) Prog Biophys Biophys Chem 7:255–318; Deshcherevski? VI (1968) Biofizika 13(5):928–935]. Here, we develop a capillary analog of the sarcomere obeying Hill’s equation and discuss its analogy with muscles. PMID:25944938

  18. Wettability inversion induced by weak electron irradiation

    SciTech Connect

    Aronov, Daniel; Molotskii, Michel

    2008-12-01

    We investigate a wettability modification of ultrathin dielectric films induced by an electron irradiation. The effect of wettability inversion, transition from hydrophobic to hydrophilic state, is predicted for low irradiation doses. It is supposed that the inversion is caused by a change in the basic mechanism of the influence of an electron irradiation on the interface free energy. For high irradiation doses, the effect of the decrease in wettability under electron irradiation is caused by the interactions of an excess charge in the film with its image charges. At low doses, the mechanism is referred to the interaction of surface charges, which function as hydrophilic adsorption centers, with water molecules. The predicted effect of the wettability inversion has been experimentally verified with electron irradiation of silicon dioxide ultrathin films. A dramatic reduction in water drop surface tension on the liquid/vapor interface has been observed. Such reduction is explained by drop charging as a result of carriers tunneling from semiconductor through ultrathin oxide layer.

  19. Motion of Drops on Surfaces with Wettability Gradients

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  20. Wettability from Capillarity of CO2-Brine-Rock Systems at Reservoir Conditions

    NASA Astrophysics Data System (ADS)

    Al-Menhali, Ali; Niu, Ben; Krevor, Samuel

    2015-04-01

    The wettability of CO2-brine-rock systems will have a major impact on the management of carbon sequestration in subsurface geological formations. Recent contact angle measurement studies have reported sensitivity in wetting behaviour of this system to pressure, temperature and brine salinity. We report results of an investigation into the impact of reservoir conditions on wetting through direct observations of their impact on the capillary strength of the system. Eight capillary pressure characteristic curves were measured using CO2 and brine in a single fired Berea sandstone at pressures (5 to 20 MPa), temperatures (25 to 50 °C) and ionic strengths (0 to 5 M kg-1 NaCl) representative of subsurface reservoirs. A ninth measurement using an N2-water system provided a benchmark for capillarity with a strongly water wet system. The semi-dynamic capillary pressure core flooding technique was used with in situ saturation monitoring. In all cases, the capillarity of the system, scaled by the interfacial tension, were equivalent to the N2-water system within measurement uncertainty. Thus reservoir conditions did not have a significant impact on the capillary strength of the CO2-brine system through a variation in wetting. Two steady-state relative permeability measurements with CO2 and brine and one with N2 and brine similarly show little variation between conditions, consistent with the observation that the CO2-brine-sandstone system is strongly water wetting and invariant across a wide range of reservoir conditions.

  1. Particle Segregation at Contact Lines of Evaporating Colloidal Drops: Influence of the Substrate Wettability and Particle Charge-Mass Ratio.

    PubMed

    Noguera-Marín, Diego; Moraila-Martínez, Carmen L; Cabrerizo-Vílchez, Miguel A; Rodríguez-Valverde, Miguel A

    2015-06-23

    Segregation of particles during capillary/convective self-assembly is interesting for self-stratification in colloidal deposits. In evaporating drops containing colloidal particles, the wettability properties of substrate and the sedimentation of particles can affect their accumulation at contact lines. In this work we studied the size segregation and discrimination of charged particles with different densities. We performed in-plane particle counting at evaporating triple lines by using fluorescence confocal microscopy. We studied separately substrates with very different wettability properties and particles with different charge-mass ratios at low ionic strength. We used binary colloidal suspensions to compare simultaneously the deposition of two different particles. The particle deposition rate strongly depends on the receding contact angle of the substrate. We further observed a singular behavior of charged polystyrene particles in binary mixtures under "salt-free" conditions explained by the "colloidal Brazil nut" effect. PMID:26000909

  2. Capillary Driven Flows Along Differentially Wetted Interior Corners

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    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.

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

    SciTech Connect

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

    2007-09-30

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

  4. Texture and Wettability of Metallic Lotus Leaves

    E-print Network

    Frankiewicz, Christophe

    2015-01-01

    Superhydrophobic surfaces with the self-cleaning behavior of lotus leaves are sought for drag reduction and phase change heat transfer applications. These superrepellent surfaces have traditionally been fabricated by random or deterministic texturing of a hydrophobic material. Recently, superrepellent surfaces have also been made from hydrophilic materials, by deterministic texturing using photolithography, without low-surface energy coating. Here, we show that hydrophilic materials can also be made superrepellent to water by chemical texturing, a stochastic rather than deterministic process. These metallic surfaces are the first analog of lotus leaves, in terms of wettability, texture and repellency. A mechanistic model is also proposed to describe the influence of multiple tiers of roughness on wettability and repellency. This demonstrated ability to make hydrophilic materials superrepellent without deterministic structuring or additional coatings opens the way to large scale and robust manufacturing of sup...

  5. Texture and Wettability of Metallic Lotus Leaves

    E-print Network

    Christophe Frankiewicz; Daniel Attinger

    2015-11-05

    Superhydrophobic surfaces with the self-cleaning behavior of lotus leaves are sought for drag reduction and phase change heat transfer applications. These superrepellent surfaces have traditionally been fabricated by random or deterministic texturing of a hydrophobic material. Recently, superrepellent surfaces have also been made from hydrophilic materials, by deterministic texturing using photolithography, without low-surface energy coating. Here, we show that hydrophilic materials can also be made superrepellent to water by chemical texturing, a stochastic rather than deterministic process. These metallic surfaces are the first analog of lotus leaves, in terms of wettability, texture and repellency. A mechanistic model is also proposed to describe the influence of multiple tiers of roughness on wettability and repellency. This demonstrated ability to make hydrophilic materials superrepellent without deterministic structuring or additional coatings opens the way to large scale and robust manufacturing of superrepellent surfaces.

  6. How does surface wettability influence nucleate boiling?

    NASA Astrophysics Data System (ADS)

    Phan, Hai Trieu; Caney, Nadia; Marty, Philippe; Colasson, Stéphane; Gavillet, Jérôme

    2009-05-01

    Although the boiling process has been a major subject of research for several decades, its physics still remain unclear and require further investigation. This study aims at highlighting the effects of surface wettability on pool boiling heat transfer. Nanocoating techniques were used to vary the water contact angle from 20° to 110° by modifying nanoscale surface topography and chemistry. The experimental results obtained disagree with the predictions of the classical models. A new approach of nucleation mechanism is established to clarify the nexus between the surface wettability and the nucleate boiling heat transfer. In this approach, we introduce the concept of macro- and micro-contact angles to explain the observed phenomenon. To cite this article: H.T. Phan et al., C. R. Mecanique 337 (2009).

  7. Nanofluids alter the surface wettability of solids.

    PubMed

    Lim, Sangwook; Horiuchi, Hiroki; Nikolov, Alex D; Wasan, Darsh

    2015-06-01

    We report the results of our studies on the changes in the contact angle and interfacial tension using a nanofluid composed of silica nanoparticles dispersed in water on three different solid substrates: gold (partially hydrophobic), glass (hydrophilic), and a silicon wafer (hydrophilic). We used both the goniometric method and drop-shape analysis to make the measurements. On the basis of the results of the drop-shape analysis using the Laplace equation, we evaluated the contributions of the interfacial tension change to the equilibrium contact angle and the presence of nanoparticles near the solid substrate, thereby elucidating the change in the wettability of the solid substrate. We found that the nanoparticles decrease the contact angle of the substrate with the increase in the nanoparticle concentration. To rationalize our experimental observations on the decrease in the contact angle of the solid substrate in the presence of nanoparticles, we calculated the surface volume fraction of the nanoparticles in the layer near the solid substrate using the particle layering model (based on the nanoparticles' excluded volume effect). We found that the volume fraction of the nanoparticles in the layer close to the substrate increased with an increase in the nanoparticle volume fraction in the bulk and correlated qualitatively with the change in the substrate wettability. The extent of the wettability alteration depends on the volume fraction of the nanoparticles, their size, and the type of substrate. We found a strong correlation between the change in the substrate wettability and the nanoparticle volume fraction in the layer closer to the substrate surface. PMID:25919686

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

    SciTech Connect

    Chang, Y.C.; Mani, V.; Mohanty, K.K.

    1997-08-01

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

  9. Capillary Origami Controlled by Electrowetting

    NASA Astrophysics Data System (ADS)

    Pineirua, Miguel; Bico, Jose; Roman, Benoit

    2010-03-01

    What happens if a water droplet is deposited over an elastic sheet? The sheet spontaneously wraps around droplet? This is possible if the capillary forces due to the liquid/air interface overcome the bending stiffness of the elastic sheet [1]. This technique called ``capillary origami'' could be used not only to encapsulate micro droplets but also to produce 3-D objects out from planar patterns. Once the microstructure has closed, could it be possible to reopen it at will? The wetting properties of liquids can be modified by the action of an electric field [2]. This phenomenon known as electrowetting can be seen as the electric energy minimization of a capacitor. In order to be capable of reopening the capillary origami, we propose to apply an electric field between the droplet and the substrate, with the flexible sheet as an isolating layer between them. The sheet will stay wrapping the droplet while the circuit is open and will eventually unwrap it if a sufficiently intense electric field is applied. We attempt to describe the original interaction between the electric field, capillarity and elasticity.[4pt] [1] C. Py, P. Reverdy, L. Doppler, J. Bico, B. Roman, C.N.Baroud, Capillary origami : spontaneous wrapping of a droplet with an elastic sheet, Phys. Rev. Lett., 98, 156103 (2007).[0pt] [2] F. Mugele, J.-C. Baret, Electrowetting : from basics to applications, J. Phys. Cond. Mat., 17, R705 (2005).

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

  11. The effects of fractional wettability on microbial enhanced oil recovery

    NASA Astrophysics Data System (ADS)

    Wildenschild, D.; Armstrong, R. T.

    2011-12-01

    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.

  12. Measurement of surface tension and viscosity by open capillary techniques

    DOEpatents

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

    1998-01-01

    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

  13. Water films, asphaltenes, and wettability alteration

    SciTech Connect

    Kaminsky, R.; Radke, C.J.

    1998-06-01

    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.

  14. Stick-Slip Control in Nanoscale Boundary Lubrication by Surface Wettability

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Foster, Adam S.; Alava, Mikko J.; Laurson, Lasse

    2015-03-01

    We study the effect of atomic-scale surface-lubricant interactions on nanoscale boundary-lubricated friction by considering two example surfaces—hydrophilic mica and hydrophobic graphene—confining thin layers of water in molecular dynamics simulations. We observe stick-slip dynamics for thin water films confined by mica sheets, involving periodic breaking-reforming transitions of atomic-scale capillary water bridges formed around the potassium ions of mica. However, only smooth sliding without stick-slip events is observed for water confined by graphene, as well as for thicker water layers confined by mica. Thus, our results illustrate how atomic-scale details affect the wettability of the confining surfaces and consequently control the presence or absence of stick-slip dynamics in nanoscale friction.

  15. Stick-Slip Control in Nanoscale Boundary Lubrication by Surface Wettability

    E-print Network

    Wei Chen; Adam S. Foster; Mikko J. Alava; Lasse Laurson

    2015-02-13

    We study the effect of atomic scale surface-lubricant interactions on nanoscale boundary-lubricated friction, by considering two example surfaces - hydrophilic mica and hydrophobic graphene - confining thin layers of water in molecular dynamics simulations. We observe stick-slip dynamics for thin water films confined by mica sheets, involving periodic breaking-reforming transitions of atomic scale capillary water bridges formed around the potassium ions of mica. However, only smooth sliding without stick-slip events is observed for water confined by graphene, as well as for thicker water layers confined by mica. Thus, our results illustrate how atomic scale details affect the wettability of the confining surfaces, and consequently control the presence or absence of stick-slip dynamics in nanoscale friction.

  16. Multiple capillary biochemical analyzer

    DOEpatents

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

    1995-01-01

    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.

  17. Multiple capillary biochemical analyzer

    DOEpatents

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

    1995-08-08

    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.

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

    PubMed

    Sedghi, Mohammad; Piri, Mohammad; Goual, Lamia

    2014-11-21

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

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

    SciTech Connect

    Sedghi, Mohammad Piri, Mohammad; Goual, Lamia

    2014-11-21

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

  20. Relative-permeability and capillary-pressure functions define how much oil can be recovered and at what rate. These functions,

    E-print Network

    Patzek, Tadeusz W.

    depend on wettability, interfacial tension, and the interplay among viscous, capillary and gravitational the motion of individual gas molecules that condense into thin films covering the rock surfaces inappropriately called "corner films") of water in contact with the nonwetting fluid. A typical pore network con

  1. Water Tank with Capillary Air/Liquid Separation

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  2. Wettability Switching Techniques on Superhydrophobic Surfaces

    PubMed Central

    2007-01-01

    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.

  3. Wettability of graphene-laminated micropillar structures

    SciTech Connect

    Bong, Jihye; Seo, Keumyoung; Ju, Sanghyun E-mail: shju@kgu.ac.kr; Park, Ji-Hoon; Ahn, Joung Real E-mail: shju@kgu.ac.kr

    2014-12-21

    The wetting control of graphene is of great interest for electronic, mechanical, architectural, and bionic applications. In this study, the wettability of graphene-laminated micropillar structures was manipulated by changing the height of graphene-laminated structures and employing the trichlorosilane (HDF-S)-based self-assembly monolayer. Graphene-laminated micropillar structures with HDF-S exhibited higher hydrophobicity (contact angle of 129.5°) than pristine graphene thin film (78.8°), pristine graphene-laminated micropillar structures (97.5°), and HDF-S self-assembled graphene thin film (98.5°). Wetting states of the graphene-laminated micropillar structure with HDF-S was also examined by using a urea solution, which flowed across the surface without leaving any residues.

  4. Condensation heat transfer coefficient versus wettability

    NASA Astrophysics Data System (ADS)

    Roudgar, M.; De Coninck, J.

    2015-05-01

    In this paper we show how condensation on substrates can induce wetting behavior that is quite different from that of deposited or impinging drops. We describe surfaces with the same wettability in ambient conditions presenting different wetting behavior and growth of droplets in condensation. The experimental results show a rapid spread of droplets and formation of the film on the copper surface, while droplets on SU-8 surface remains on the regular shape while they grow within the time, without coalescence, as observed for Cu. Although the heat conductivity of SU-8 is much lower, due to a difference in wetting behavior, the heat transfer coefficient (h) is higher for dropwise condensation on Cu with a thin layer of SU-8 than filmwise on the bare copper.

  5. Wettability of graphene-laminated micropillar structures

    NASA Astrophysics Data System (ADS)

    Bong, Jihye; Seo, Keumyoung; Park, Ji-Hoon; Ahn, Joung Real; Ju, Sanghyun

    2014-12-01

    The wetting control of graphene is of great interest for electronic, mechanical, architectural, and bionic applications. In this study, the wettability of graphene-laminated micropillar structures was manipulated by changing the height of graphene-laminated structures and employing the trichlorosilane (HDF-S)-based self-assembly monolayer. Graphene-laminated micropillar structures with HDF-S exhibited higher hydrophobicity (contact angle of 129.5°) than pristine graphene thin film (78.8°), pristine graphene-laminated micropillar structures (97.5°), and HDF-S self-assembled graphene thin film (98.5°). Wetting states of the graphene-laminated micropillar structure with HDF-S was also examined by using a urea solution, which flowed across the surface without leaving any residues.

  6. Surface wettability studies of PDMS using flame plasma treatment

    E-print Network

    Wang, Xin C

    2009-01-01

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

  7. Effect of rust on the wettability of steel by water

    SciTech Connect

    Lu, W.; Chung, D.D.L.

    1998-04-01

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

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

    NASA Astrophysics Data System (ADS)

    Al-Menhali, Ali; Krevor, Samuel

    2014-05-01

    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.

  9. Wettability alteration of oil-wet carbonate by silica nanofluid.

    PubMed

    Al-Anssari, Sarmad; Barifcani, Ahmed; Wang, Shaobin; Maxim, Lebedev; Iglauer, Stefan

    2016-01-01

    Changing oil-wet surfaces toward higher water wettability is of key importance in subsurface engineering applications. This includes petroleum recovery from fractured limestone reservoirs, which are typically mixed or oil-wet, resulting in poor productivity as conventional waterflooding techniques are inefficient. A wettability change toward more water-wet would significantly improve oil displacement efficiency, and thus productivity. Another area where such a wettability shift would be highly beneficial is carbon geo-sequestration, where compressed CO2 is pumped underground for storage. It has recently been identified that more water-wet formations can store more CO2. We thus examined how silica based nanofluids can induce such a wettability shift on oil-wet and mixed-wet calcite substrates. We found that silica nanoparticles have an ability to alter the wettability of such calcite surfaces. Nanoparticle concentration and brine salinity had a significant effect on the wettability alteration efficiency, and an optimum salinity was identified, analogous to that one found for surfactant formulations. Mechanistically, most nanoparticles irreversibly adhered to the oil-wet calcite surface (as substantiated by SEM-EDS and AFM measurements). We conclude that such nanofluid formulations can be very effective as enhanced hydrocarbon recovery agents and can potentially be used for improving the efficiency of CO2 geo-storage. PMID:26414426

  10. Water absorption kinetics in different wettability conditions studied at pore and sample scales in porous media by NMR with portable single-sided and laboratory imaging devices

    NASA Astrophysics Data System (ADS)

    Bortolotti, V.; Camaiti, M.; Casieri, C.; De Luca, F.; Fantazzini, P.; Terenzi, C.

    2006-08-01

    NMR relaxation time distributions of water 1H obtained by a portable single-sided surface device have been compared with MRI internal images obtained with a laboratory imaging apparatus on the same biocalcarenite (Lecce Stone) samples during capillary water uptake. The aim of this work was to check the ability of NMR methods to quantitatively follow the absorption phenomenon under different wettability conditions of the internal pore surfaces. Stone wettability changes were obtained by capillary absorption of a chloroform solution of Paraloid PB72, a hydrophobic acrylic resin frequently used to protect monuments and buildings, through one face of each sample. Both relaxation and imaging data have been found in good quantitative agreement each other and with masses of water determined by weighing the samples. In particular the Washburn model of water capillary rise applied to the imaging data allowed us to quantify the sorptivity in both treated and untreated samples. Combining relaxation and imaging data, a synergetic improvement of our understanding of the water absorption kinetics at both pore and sample scales is obtained. Since relaxation data have been taken over the course of time without interrupting the absorption process, simply by keeping the portable device on the surface opposite to the absorption, the results show that the single-sided NMR technique is a powerful tool for in situ evaluation of water-repellent treatments frequently used for consolidation and/or protection of stone artifacts.

  11. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1996-12-10

    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.

  12. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1998-04-21

    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.

  13. Multiplexed capillary electrophoresis system

    DOEpatents

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

    1998-04-21

    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.

  14. Multiplexed capillary electrophoresis system

    DOEpatents

    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

    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.

  15. Nasal Lobular Capillary Hemangioma

    PubMed Central

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

    2013-01-01

    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. PMID:24228209

  16. Surface-directed capillary system; theory, experiments and applications Salim Bouaidat,*ab

    E-print Network

    are in good agreement with the experimental results. The capillarity-driven microflow system was also used is by capillary action. Capillarity or capillary action is a common physical phenomenon, where liquids wet-to-volume ratio. Conventional capillarity-driven systems consist of closed micro channels, where the liquid

  17. Displaced capillary dies

    DOEpatents

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

    1984-01-01

    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.

  18. Displaced capillary dies

    DOEpatents

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

    1982-01-01

    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.

  19. Capillary discharge source

    DOEpatents

    Bender, III, Howard Albert

    2003-11-25

    Debris generation from an EUV electric discharge plasma source device can be significantly reduced or essentially eliminated by encasing the electrodes with dielectric or electrically insulating material so that the electrodes are shielded from the plasma, and additionally by providing a path for the radiation to exit wherein the electrodes are not exposed to the area where the radiation is collected. The device includes: (a) a body, which is made of an electrically insulating material, that defines a capillary bore that has a proximal end and a distal end and that defines at least one radiation exit; (b) a first electrode that defines a first channel that has a first inlet end that is connected to a source of gas and a first outlet end that is in communication with the capillary bore, wherein the first electrode is positioned at the distal end of the capillary bore; (c) a second electrode that defines a second channel that has a second inlet end that is in communication with the capillary bore and an outlet end, wherein the second electrode is positioned at the proximal end of the capillary bore; and (d) a source of electric potential that is connected across the first and second electrodes, wherein radiation generated within the capillary bore is emitted through the at least one radiation exit and wherein the first electrode and second electrode are shielded from the emitted radiation.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    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.

  1. Capillary pressure and saturation relations for supercritical CO2 and brine in sand: High-pressure Pc(Sw) controller/meter measurements and capillary scaling predictions

    NASA Astrophysics Data System (ADS)

    Tokunaga, Tetsu K.; Wan, Jiamin; Jung, Jong-Won; Kim, Tae Wook; Kim, Yongman; Dong, Wenming

    2013-08-01

    In geologic carbon sequestration, reliable predictions of CO2 storage require understanding the capillary behavior of supercritical (sc) CO2. Given the limited availability of measurements of the capillary pressure (Pc) dependence on water saturation (Sw) with scCO2 as the displacing fluid, simulations of CO2 sequestration commonly rely on modifying more familiar air/H2O and oil/H2O Pc(Sw) relations, adjusted to account for differences in interfacial tensions. In order to test such capillary scaling-based predictions, we developed a high-pressure Pc(Sw) controller/meter, allowing accurate Pc and Sw measurements. Drainage and imbibition processes were measured on quartz sand with scCO2-brine at pressures of 8.5 and 12.0 MPa (45°C), and air-brine at 21°C and 0.1 MPa. Drainage and rewetting at intermediate Sw levels shifted to Pc values that were from 30% to 90% lower than predicted based on interfacial tension changes. Augmenting interfacial tension-based predictions with differences in independently measured contact angles from different sources led to more similar scaled Pc(Sw) relations but still did not converge onto universal drainage and imbibition curves. Equilibrium capillary trapping of the nonwetting phases was determined for Pc = 0 during rewetting. The capillary-trapped volumes for scCO2 were significantly greater than for air. Given that the experiments were all conducted on a system with well-defined pore geometry (homogeneous sand), and that scCO2-brine interfacial tensions are fairly well constrained, we conclude that the observed deviations from scaling predictions resulted from scCO2-induced decreased wettability. Wettability alteration by scCO2 makes predicting hydraulic behavior more challenging than for less reactive fluids.

  2. Fabrication of high wettability gradient on copper substrate

    NASA Astrophysics Data System (ADS)

    Huang, Ding-Jun; Leu, Tzong-Shyng

    2013-09-01

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

  3. The tunable wettability in multistimuli-responsive smart graphene surfaces

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

    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.

  4. Efficient water collection on integrative bioinspired surfaces with star-shaped wettability patterns.

    PubMed

    Bai, Hao; Wang, Lin; Ju, Jie; Sun, Ruize; Zheng, Yongmei; Jiang, Lei

    2014-08-01

    Inspired by the water-collecting strategies of desert beetles and spider silk, a novel kind of surface with star-shaped wettablity patterns has been developed. By combining both wettability and shape gradients, the as-prepared surface has gained higher efficiency in water collection compared to circle-shaped wettability patterns and uniformly superhydrophilic or superhydrophobic surfaces. PMID:24847736

  5. Capillary condenser/evaporator

    NASA Technical Reports Server (NTRS)

    Valenzuela, Javier A. (Inventor)

    2010-01-01

    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.

  6. Instant capillary origami

    NASA Astrophysics Data System (ADS)

    Rivetti, Marco; Audoly, Basile; Neukirch, Sebastien; Josserand, Christophe; Antkowiak, Arnaud

    2010-11-01

    A liquid drop impacting a thin elastic membrane forms a "dynamical capillary origami" on the very rapid capillary timescale. Dynamics is here a key ingredient that allows for shape selection of the elastocapillary bundle based only on the impact velocity. We study this phenomenon using a simplified 2D setup, where a drop impacts a narrow polymer strip. This experiment exhibits a surprisingly rich variety of phenomena: coupled capillary and elastic waves, drop breakup, jet ejection...We propose a very simple rod dynamics numerical model that mimics the complex fluid-structure interactions at play. The results of this model are in close agreement with the full experiment, both in the qualitative dynamics of folding and in the quantitative representation of the phase diagram of encapsulation. Eventually, we discuss how drop dynamics may induce anomalous encapsulation events where unexpectedly long strips are wrapped around drops.

  7. Entropy and the driving force for the filling of carbon nanotubes with water

    E-print Network

    Goddard III, William A.

    in nanofluidics, nanofiltrations, and desalination. wettability porous media capillary action Nanofluidics and nanofiltration have emerged quite recently as an intriguing interdisciplinary science, with applications

  8. Partial Wetting in Capillary Liquid Absorption by Limestones.

    PubMed

    Taylor; Hall; Hoff; Wilson

    2000-04-15

    We report measurements of the capillary absorption (imbibition) of water, n-heptane, n-decane, n-dodecane, methanol, ethanol, propan-2-ol, and ethanol-water mixtures into a number of dry calcitic limestones. The data are analyzed on the basis of unsaturated flow theory to give values of sorptivity S for water and for each organic liquid at different temperatures. The results show that for the organic liquids S varies as (surface tension/viscosity)(1/2) but that for the water S is anomalously low, indicating partial wetting. The wettability of these limestones is discussed in relation to natural contamination of the pore surface. Copyright 2000 Academic Press. PMID:10727347

  9. Autoclaving as a mean of modifying the soil wettability characteristics

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    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.

  10. Microbial enhanced oil recovery and wettability research program

    SciTech Connect

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

    1991-07-01

    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.

  11. Capillary Isoelectric Focusing

    NASA Astrophysics Data System (ADS)

    Markuszewski, Micha? J.; Bujak, Renata; Daghir, Emilia

    Capillary isoelectric focusing (CIEF) is a widespread technique for the analysis of peptides and proteins in biological samples. CIEF is used to separate mixtures of compounds on the basis of differences in their isoelectric point. Aspects of sample preparation, capillary selection, zone mobilization procedures as well as various detection modes used have been described and discussed. Moreover CIEF, coupled to various types of detection techniques (MALDI or LIF), has increasingly been applied to the analysis of variety different high-molecular compounds. CIEF is considered as a highly specific analytical method which may be routinely used in the separation of rare hemoglobin variants. In addition, the application of CIEF in proteomic field have been discussed on the examples of analyses of glycoproteins and immunoglobins due to the meaning in clinical diagnostic.

  12. Capillary Waveguide Biosensor Platform

    NASA Astrophysics Data System (ADS)

    Dhadwal, Harbans S.

    The design and characterization of a fully automated and portable capillary waveguide biosensor are discussed in this chapter. Highly specific target recognition is achieved through hybridization of fluid-borne single-stranded DNA sequences extracted from natural targets to the complimentary nucleic acid sequence ("capture probe") bound to the inner surface of a capillary. The product of hybridization is enumerated through the use of fluorescent labeling. A novel instantaneous normalization scheme based on two photodetectors, together with the use of a standard reference material, enables independent measurements by the instrument. The probability of false-positive target detection is quantified through the development of a target detection error rate. The instrument exhibits low detection limits (~10-13 M) and repeatability of 6%. The sensor can be rearmed through a denaturing step allowing for sequential detection over an extended time period.

  13. Automated Parallel Capillary Electrophoretic System

    DOEpatents

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

    2000-02-22

    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 carousel 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.

  14. LED-controlled tuning of ZnO nanowires’ wettability for biosensing applications

    PubMed Central

    Bhavsar, Kaushalkumar; Ross, Duncan; Prabhu, Radhakrishna; Pollard, Pat

    2015-01-01

    Background Wettability is an important property of solid materials which can be controlled by surface energy. Dynamic control over the surface wettability is of great importance for biosensing applications. Zinc oxide (ZnO) is a biocompatible material suitable for biosensors and microfluidic devices. Nanowires of ZnO tend to show a hydrophobic nature which decelerates the adhesion or adsorption of biomolecules on the surface and, therefore, limits their application. Methods Surface wettability of the ZnO nanowires can be tuned using light irradiation. However, the control over wettability using light-emitting diodes (LEDs) and the role of wavelength in controlling the wettability of ZnO nanowires are unclear. This is the first report on LED-based wettability control of nanowires, and it includes investigations on tuning the desired wettability of ZnO nanowires using LEDs as a controlling tool. Results The investigations on spectral properties of the LED emission on ZnO nanowires’ wettability have shown strong dependency on the spectral overlap of LED emission on ZnO absorption spectra. Results indicate that LEDs offer an advanced control on dynamically tuning the wettability of ZnO nanowires. Conclusion The spectral investigations have provided significant insight into the role of irradiating wavelength of light and irradiation time on the surface wettability of ZnO nanowires. This process is suitable to realize on chip based integrated sensors and has huge potential for eco-friendly biosensing and environmental sensing applications. PMID:25855065

  15. Evaluation of Reservoir Wettability and its Effect on Oil Recovery

    SciTech Connect

    Jill S. Buckley

    1998-06-12

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

  16. Nanosecond laser texturing of aluminium for control of wettability

    NASA Astrophysics Data System (ADS)

    Sharp, Martin C.; Rosowski, Adam P.; French, Paul W.

    2015-07-01

    There is increasing interest in the use of lasers to modify the wettability of surfaces. Here we report on the use of a 20W nS pulsed IR fibre laser to create strong hydrophobicity on the surface of aluminium sheets. This is unexpected, hydrophobicity is usually associated solely with femto- or pico- second laser processing. At a 20W average power level the area coverage rate is too small for many industrial applications. Further trials using a 800W DPSS laser are described and the ability of this system to change surface wettability at a much higher production rate are indicated. There is little reported literature on surface texturing at higher average power levels. Indications of the productivity, or surface coverage rate, are given.

  17. Capillary reference half-cell

    DOEpatents

    Hall, S.H.

    1996-02-13

    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.

  18. Capillary reference half-cell

    DOEpatents

    Hall, Stephen H. (Kennewick, WA)

    1996-01-01

    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.

  19. Bio-inspired electrospun micro/nanofibers with special wettability.

    PubMed

    Baji, Avinash; Abtahi, Mojtaba; Ramakrishna, Seeram

    2014-07-01

    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

  20. Patterned wettability of oil and water in porous media.

    PubMed

    Kumar, Munish; Fogden, Andrew

    2010-03-16

    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

  1. Surface morphology and wettability of sandblasted PEEK and its composites.

    PubMed

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

    2014-01-01

    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

  2. Wettability of Freon hydrates in crude oil/brine emulsions.

    PubMed

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

    2005-07-01

    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

  3. Ultrasound assisted cleaning of ceramic capillary filter.

    PubMed

    Pirkonen, P; Grönroos, A; Heikkinen, J; Ekberg, B

    2010-08-01

    Research in the fields of filtration and dewatering connected with the use of ultrasound (US) has been carried out mainly with small laboratory-scale batch or continuously operating devices. So far the only large scale industrial cake filtration applications have been developed and manufactured by Larox Oyj for mining industry. These applications apply ultrasound for cleaning of ceramic capillary action elements having at maximum total filtration area of approximately 150 m(2). Several hundreds of filter units have been delivered worldwide during the past two decades. PMID:19932635

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

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

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

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

    SciTech Connect

    Mukul M. Sharma; George J. Hirasaki

    2003-09-01

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

  6. Capillary scale admittance detection.

    PubMed

    Zhang, Min; Stamos, Brian N; Amornthammarong, Natchanon; Dasgupta, Purnendu K

    2014-12-01

    Techniques that have been variously termed oscillometric detection or (capacitively coupled) contactless conductivity detection (C(4)D) are known actually to respond to the admittance. It is not often appreciated that the frequency range (f) over which such systems respond (quasi)linearly with the cell conductance decreases acutely with increasing cell resistance. Guidance on optimum operating conditions for high cell resistance, such as for very small capillaries/channels and/or solutions of low specific conductance (?), is scant. It is specially necessary in this case to take the capacitance of the solution into account. At high frequencies and low ? values, much of the current passes through the solution behaving as a capacitor and the capacitance is not very dependent on the exact solution specific conductance, resulting in poor, zero, or even negative response. We investigated, both theoretically and experimentally, capillaries with inner radii of 5-160 ?m and ? ? 1-1400 ?S/cm, resulting in cell resistances of 51 G? to 176 k?. A 400-element discrete model was used to simulate the behavior. As model inputs, both the wall capacitance and the stray capacitance were measured. The solution and leakage capacitances were estimated from extant models. The model output was compared to the measured response of the detection system over broad ranges of f and ?. Other parameters studied include capillary material and wall thickness, electrode spacing and length, Faraday shield thickness, excitation wave forms, and amplitude. The simulations show good qualitative agreement with experimental results and correctly predict the negative response behavior observed under certain conditions. We provide optimum frequencies for different operating conditions. PMID:25355014

  7. Capillary suspensions: Particle networks formed through the capillary force

    E-print Network

    Erin Koos

    2014-11-18

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

  8. Capillary suspensions: Particle networks formed through the capillary force

    PubMed Central

    Koos, Erin

    2014-01-01

    The addition of small amounts of a secondary fluid to a suspension can, through the attractive capillary force, lead to particle bridging and network formation. The capillary bridging phenomenon can be used to stabilize particle suspensions and precisely tune their rheological properties. This effect can even occur when the secondary fluid wets the particles less well than the bulk fluid. These materials, so-called capillary suspensions, have been the subject of recent research studying the mechanism for network formation, the properties of these suspensions, and how the material properties can be modified. Recent work in colloidal clusters is summarized and the relationship to capillary suspensions is discussed. Capillary suspensions can also be used as a pathway for new material design and some of these applications are highlighted. Results obtained to date are summarized and central questions that remain to be answered are proposed in this review. PMID:25729316

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

    SciTech Connect

    Sharma, Mukul M.; Hirasaki, George J.

    2002-01-28

    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.

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

    SciTech Connect

    Petrusak, Robin; Heath, Jason E.; McPherson, Brian J. O. L.; Dewers, Thomas A.; Kotula, Paul Gabriel

    2010-08-01

    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.

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

    SciTech Connect

    Heath, Jason E.; Nemer, Martin B.; McPherson, Brian J. O. L.; Dewers, Thomas A.; Kotula, Paul Gabriel

    2010-12-01

    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.

  12. Tapered capillary optics

    DOEpatents

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

    1998-01-01

    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.

  13. Biomedical applications of capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Kartsova, L. A.; Bessonova, E. A.

    2015-08-01

    The review deals with modern analytical approaches used in capillary electrophoresis for solving medical and biological problems: search for biomarkers of various diseases and rapid diagnosis based on characteristic profiles of biologically active compounds by capillary electrophoresis with mass spectrometric detection; monitoring of the residual drugs in biological fluids for evaluating the efficiency of drug therapy; testing of the enantiomeric purity of pharmaceutical products; the use of novel materials as components of stationary and pseudo-stationary phases in capillary electrophoresis and capillary electrochromatography to increase the selectivity of separation of components of complex matrices; and identification of various on-line preconcentration techniques to reduce the detection limits of biologically active analytes. A topical trend in capillary electrophoresis required in clinical practice, viz., the design of microfluidic systems, is discussed. The bibliography includes 173 references.

  14. Noise suppressing capillary separation system

    DOEpatents

    Yeung, E.S.; Xue, Y.

    1996-07-30

    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.

  15. Capillary ratchet: Hydrodynamics of capillary feeding in shorebirds

    NASA Astrophysics Data System (ADS)

    Prakash, Manu; Quere, David; Bush, John

    2008-03-01

    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.

  16. Capillaries for use in a multiplexed capillary electrophoresis system

    DOEpatents

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

    1997-12-09

    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.

  17. Capillaries for use in a multiplexed capillary electrophoresis system

    DOEpatents

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

    1997-12-09

    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.

  18. Steady Capillary Driven Flow

    NASA Technical Reports Server (NTRS)

    Weislogel, Mark M.

    1996-01-01

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

  19. Capillary interconnect device

    DOEpatents

    Renzi, Ronald F. (Tracy, CA)

    2007-12-25

    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.

  20. Surfactant loss: Effects of temperature, salinity, and wettability

    SciTech Connect

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

    1989-05-01

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

  1. Wettability manipulation of magnetic transition metal nanorod arrays by X-ray irradiation

    NASA Astrophysics Data System (ADS)

    Xie, Qian; Wang, Weipeng; Xie, Zheng; Shuang, Shuang; Li, Zhengcao; Zhang, Zhengjun

    2015-09-01

    Wettability manipulation of glancing angle deposited Fe/Co/Ni nanorod arrays was realized by X-ray irradiation in ultra-high vacuum chamber. Reversible transition was also purchased by alternating ethanol immersion and X-ray irradiation. Alkyl group adsorption-desorption mechanism and corresponding morphology dependence of wettability manipulation were revealed.

  2. Stimuli-Responsive Surfaces for Tunable and Reversible Control of Wettability.

    PubMed

    Huang, Xu; Sun, Yajuan; Soh, Siowling

    2015-07-15

    Surfaces with controllable wettability can be fabricated by embedding superhydrophobic particles into stimuli-responsive hydrogels. When the hydrogel changes its size due to a specific stimulus, the wettability of the surface can be reversibly tuned from superhydrophobic to superhydrophilic. This general method is used to fabricate "smart" membranes for controlling the permeability of chemicals under the influence of multiple stimuli simultaneously. PMID:26043083

  3. A COMPARATIVE STUDY OF THE WETTABILITY OF STEEL, CARBON, AND POLYETHYLENE FIBERS BY WATER

    E-print Network

    Chung, Deborah D.L.

    A COMPARATIVE STUDY OF THE WETTABILITY OF STEEL, CARBON, AND POLYETHYLENE FIBERS BY WATER W. Lu, X at Buffalo, Buffalo, NY 14260-4400, USA (Received March 9, 1998; in final form April 10, 1998) ABSTRACT The wettability of fibers by water was found to increase in this order: polyethylene fiber, steel fiber

  4. Nickel Phase Wettability and YSZ Redox Fracture Percolation in Solid Oxide Fuel Cell Anodes

    E-print Network

    Petta, Jason

    Nickel Phase Wettability and YSZ Redox Fracture Percolation in Solid Oxide Fuel Cell Anodes Alex, systems with higher nickel wettability (lower contact angles) fracture at nearly the same rate, contrasted DMR-1156422 (PI: Prof. Mikko Haataja) PREM CSUN Prime # NSF 1205734 Nickel Strain 90° 73°136° 104

  5. Integrated multiplexed capillary electrophoresis system

    DOEpatents

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

    2002-05-14

    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.

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

    NASA Astrophysics Data System (ADS)

    Armstrong, R. T.; Wildenschild, D.

    2010-12-01

    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.

  7. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

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

    1999-01-01

    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.

  8. Impact of Wettability on Fracturing of Nano-Granular Materials

    NASA Astrophysics Data System (ADS)

    Trojer, M.; Juanes, R.

    2014-12-01

    Hydraulic fracturing, or fracking, is a well-known reservoir stimulation technique, by which the permeability of the near-wellbore region is enhanced through the creation of tensile fractures within the rock, formed in the direction perpendicular to the least principal stress. While it is well known that fracturing of granular media strongly depends on the type of media, the pore fluids, and the fracking fluids, the interplay between multiphase flow, wettability and fracture mechanics of shale-like (nano-granular) materials remains poorly understood. Here, we study experimentally the dynamics of multiphase-flow fracking in nano-porous media and its dependence on the wetting properties of the system. The experiments consist in saturating a thin bed of glass beads with a viscous fluid, injecting a less viscous fluid, and imaging the invasion morphology. We investigate three control parameters: the injection rate of the less-viscous invading phase, the confining stress, and the contact angle, which we control by altering the surface chemistry of the beads and the Hele-Shaw cell. We quantify the dynamic fracture pattern by means of particle image velocimetry (PIV), and elucidate the role of wettability on the emerging flow physics at the length scale of the viscous-frictional instability.

  9. Effects of surface wettability on fast liquid transfer

    NASA Astrophysics Data System (ADS)

    Chen, H.; Tang, T.; Amirfazli, A.

    2015-11-01

    A systematic experimental study was performed to understand the role of surface contact angles in affecting the process of fast liquid transfer. Surfaces with different wettabilities were used, and the transfer ratio (?, the amount of liquid transferred to the acceptor surface over the total amount of liquid) was measured for each pair of surfaces. A numerical model based on the volume of fluid method was developed to help understand the experimental results. The surface wettability was shown to significantly affect the boundaries between three regimes based on stretching speeds: quasi-static (surface force dominated), transition (surface/viscous/inertia forces all important) and dynamic (viscous/inertia forces dominated). Specifically, the values of the boundary speeds were found to increase with |?0 - 0.5|, where ?0 is the transfer ratio in the quasi-static regime, and ?0 is governed by the surface receding contact angles. Based on our results, an empirical equation to describe the transfer ratio as function of stretching speed was proposed. This equation can also be used as a prediction tool for the value of ? for a fast transfer system.

  10. Effect of wettability on adverse mobility immiscible floods

    SciTech Connect

    Vives, M.T.; Chang, Y.C.; Mohanty, K.K.

    1995-12-31

    Many immiscible displacements in reservoirs occur at adverse mobility. Effect of wettability on these displacements is not well understood and often ignored in reservoir simulation. Recent macroscopic theories of viscous fingering treat adverse immiscible flows similar to miscible flows, the mixing in the fingered region being controlled by a Todd-Longstaff-type functional form. The wettability of the medium is taken into account only through the use of appropriate relative permeabilities. The goal of this paper is to understand the macroscopic bypassing in adverse mobility immiscible floods. Immiscible displacements are conducted in a quarter 5-spot model in both drainage and imbibition modes at similar effective mobility ratios and viscous-to-gravity numbers. The level of bypassing and gravity override is visualized and measured. Tertiary water-alternating-gas (WAG) displacements are also conducted at various WAG ratios and viscosity ratios. Fractional flow analysis and numerical simulation are used to understand these displacements. Experiments show that macroscopic viscous fingering is present in adverse viscosity immiscible displacements where no saturation shock is expected from 1-D fractional flow theory. Bypassing due to both fingering and gravity override is higher in the drainage mode than in the imbibition mode, with other key parameters being the same. Optimum WAG ratio in water-wet rock is a function of oil/solvent viscosity ratio. The macroscopic flow theory needs to include capillarity and viscous fingering to match these experimental findings.

  11. Fog collecting biomimetic surfaces: Influence of microstructure and wettability.

    PubMed

    Azad, M A K; Ellerbrok, D; Barthlott, W; Koch, K

    2015-01-01

    We analyzed the fog collection efficiency of three different sets of samples: replica (with and without microstructures), copper wire (smooth and microgrooved) and polyolefin mesh (hydrophilic, superhydrophilic and hydrophobic). The collection efficiency of the samples was compared in each set separately to investigate the influence of microstructures and/or the wettability of the surfaces on fog collection. Based on the controlled experimental conditions chosen here large differences in the efficiency were found. We found that microstructured plant replica samples collected 2-3 times higher amounts of water than that of unstructured (smooth) samples. Copper wire samples showed similar results. Moreover, microgrooved wires had a faster dripping of water droplets than that of smooth wires. The superhydrophilic mesh tested here was proved more efficient than any other mesh samples with different wettability. The amount of collected fog by superhydrophilic mesh was about 5 times higher than that of hydrophilic (untreated) mesh and was about 2 times higher than that of hydrophobic mesh. PMID:25599517

  12. Initial biocompatibility of plasma polymerized hexamethyldisiloxane films with different wettability

    NASA Astrophysics Data System (ADS)

    Krasteva, N. A.; Toromanov, G.; Hristova, K. T.; Radeva, E. I.; Pecheva, E. V.; Dimitrova, R. P.; Altankov, G. P.; Pramatarova, L. D.

    2010-11-01

    Understanding the relationships between material surface properties, behaviour of adsorbed proteins and cellular responses is essential to design optimal material surfaces for tissue engineering. In this study we modify thin layers of plasma polymerized hexamethyldisiloxane (PPHMDS) by ammonia treatment in order to increase surface wettability and the corresponding biological response. The physico-chemical properties of the polymer films were characterized by contact angle (CA) measurements and Fourier Transform Infrared Spectroscopy (FTIR) analysis.Human umbilical vein endothelial cells (HUVEC) were used as model system for the initial biocompatibility studies following their behavior upon preadsorption of polymer films with three adhesive proteins: fibronectin (FN), fibrinogen (FG) and vitronectin (VN). Adhesive interaction of HUVEC was evaluated after 2 hours by analyzing the overall cell morphology, and the organization of focal adhesion contacts and actin cytoskeleton. We have found similar good cellular response on FN and FG coated polymer films, with better pronounced vinculin expression on FN samples while. Conversely, on VN coated surfaces the wettability influenced significantly initial celular interaction spreading. The results obtained suggested that ammonia plasma treatment can modulate the biological activity of the adsorbed protein s on PPHMDS surfaces and thus to influence the interaction with endothelial cells.

  13. Wetting in Color: Designing a colorometric indicator for wettability

    NASA Astrophysics Data System (ADS)

    Raymond, Kevin; Burgess, Ian B.; Koay, Natalie; Kolle, Mathias; Loncar, Marko; Aizenberg, Joanna

    2012-02-01

    Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. While such indicators commonly rely on a specific photochemical response to an analyte, we exploit structural color, derived from coherent scattering from wavelength-scale porosity rather than molecular absorption or luminescence, to create a Wetting-in-Color-Kit (WICK). This inexpensive and highly selective colorimetric indicator for organic liquids employs chemically encoded inverse-opal photonic crystals to translate minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize color patterns. The highly symmetric re-entrant inter-pore geometry imparts a highly specific wetting threshold for liquids. We developed surface modification techniques to generate built-in chemistry gradients within the porous network. These let us tailor the wettability threshold to specific liquids across a continuous range. As wetting is a generic fluidic phenomenon, we envision that WICK could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries.

  14. DNA typing by capillary electrophoresis

    SciTech Connect

    Zhang, N.

    1997-10-08

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

  15. Surface Tension and Capillary Rise

    ERIC Educational Resources Information Center

    Walton, Alan J.

    1972-01-01

    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)

  16. Salinity Influence on Interfacial Area, Wettability, and NAPL Recovery

    NASA Astrophysics Data System (ADS)

    Zhong, L.; Valenta, M. M.

    2007-12-01

    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.

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

    PubMed Central

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

    2010-01-01

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

  18. Capillary pressure - saturation relations for supercritical CO2 and brine: Implications for capillary/residual trapping in carbonate reservoirs during geologic carbon sequestration

    NASA Astrophysics Data System (ADS)

    Wang, S.; Tokunaga, T. K.

    2014-12-01

    In geologic carbon sequestration (GCS), data on capillary pressure (Pc) - saturation (Sw) relations are routinely needed to appraise reservoir processes. Capillarity and its hysteresis have been often experimentally studied in oil-water, gas-water and three phase gas-oil-water systems, but fewer works have been reported on scCO2-water under in-situ reservoir conditions. Here, Pc-Sw relations of supercritical (sc) CO2 displacing brine, and brine rewetting the porous medium to trap scCO2 were studied to understand CO2 transport and trapping behavior in carbonate reservoirs under representative reservoir conditions. High-quality drainage and imbibition (and associated capillary pressure hysteresis) curves were measured under elevated temperature and pressure (45 ºC, 8.5 and 12 MPa) for scCO2-brine as well as at room temperature and pressure (23 ºC, 0.1 MPa) for air-brine in unconsolidated limestone and dolomite sand columns using newly developed semi-automated multistep outflow-inflow porous plate apparatus. Drainage and imbibition curves for scCO2-brine deviated from the universal scaling curves for hydrophilic interactions (with greater deviation under higher pressure) and shifted to lower Pc than predicted based on interfacial tension (IFT) changes. Augmented scaling incorporating differences in IFT and contact angle improved the scaling results but the scaled curves still did not converge onto the universal curves. Equilibrium residual trapping of the nonwetting phase was determined at Pc =0 during imbibition. The capillary-trapped amounts of scCO2 were significantly larger than for air. It is concluded that the deviations from the universal capillary scaling curves are caused by scCO2-induced wettability alteration, given the fact that pore geometry remained constant and IFT is well constrained. In-situ wettability alteration by reactive scCO2 is of critical importance and must be accounted for to achieve reliable predictions of CO2 behavior in GCS reservoirs.

  19. An Alternative Approach to Evaluate the Wettability of Carbon Fiber Substrates.

    PubMed

    Sow, Pradeep Kumar; Prass, Sebastian; Mérida, Walter

    2015-10-01

    The wettability of carbon fiber substrate plays an important role in a vast number of electrochemical energy production and storage technologies. Here, we report an alternative approach to evaluate the relative wettability for three substrates with the solid-liquid (S-L) interfacial area as the wettability parameter. We applied electrochemical techniques to quantify the S-L interfacial area and obtained the relative wettability on for three substrates with varying fiber morphology. This work proposes and validates a methodology to experimentally measure the substrate wettability and elucidates important aspects of the relevant wetting phenomena. Our results indicate that the wettability of carbon fiber substrate is affected by the liquid intrusion resulting from the instability of the Cassie-Baxter wetting state and that the contact angle is not dependent on the S-L interfacial area under the droplet. The present technique can be used to characterize the surface wettability of a wide range of conductive surfaces with irregular and multiscale surface roughness features. PMID:26375575

  20. Evaluation of Reservoir Wettability and its Effect on Oil Recovery.

    SciTech Connect

    Buckley, J.S.

    1998-01-15

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

  1. Capillary flow enhancement in rectangular polymer microchannels with a deformable wall.

    PubMed

    Anoop, R; Sen, A K

    2015-07-01

    We report the capillary flow enhancement in rectangular polymer microchannels, when one of the channel walls is a deformable polymer membrane. We provide detailed insight into the physics of elastocapillary interaction between the capillary flow and elastic membrane, which leads to significant improvements in capillary flow performance. As liquid flows by capillary action in such channels, the deformable wall deflects inwards due to the Young-Laplace pressure drop across the liquid meniscus. This, in turn, decreases the radius of curvature of the meniscus and increases the driving capillary pressure. A theoretical model is proposed to predict the resultant increase in filling speed and rise height, respectively, in deformable horizontal and vertical microchannels having large aspect ratios. A non-dimensional parameter J, which represents the ratio of the capillary force to the mechanical restoring force, is identified to quantify the elastocapillary effects in terms of the improvement in filling speed (for J>0.238) and the condition for channel collapse (J>1). The theoretical predictions show good agreement with experimental data obtained using deformable rectangular poly(dimethylsiloxane) microchannels. Both model predictions and experimental data show that over 15% improvement in the Washburn coefficient in horizontal channels, and over 30% improvement in capillary rise height in vertical channels, are possible prior to channel collapse. The proposed technique of using deformable membranes as channel walls is a viable method for capillary flow enhancement in microfluidic devices. PMID:26274286

  2. Curvature Capillary Migration of Microspheres

    E-print Network

    Nima Sharifi-Mood; Iris B. Liu; Kathleen J. Stebe

    2015-05-11

    We address the question: How does capillarity propel microspheres along curvature gradients? For a particle on a fluid interface, there are two conditions that can apply at the three phase contact line: Either the contact line adopts an equilibrium contact angle, or it can be pinned by kinetic trapping, e.g. at chemical heterogeneities, asperities or other pinning sites on the particle surface. We formulate the curvature capillary energy for both scenarios for particles smaller than the capillary length and far from any pinning boundaries. The scale and range of the distortion made by the particle are set by the particle radius; we use singular perturbation methods to find the distortions and to rigorously evaluate the associated capillary energies. For particles with equilibrium contact angles, contrary to the literature, we find that the capillary energy is negligible, with the first contribution bounded to fourth order in the product of the particle radius and the deviatoric curvature. For pinned contact lines, we find curvature capillary energies that are finite, with a functional form investigated previously by us for disks and microcylinders on curved interfaces. In experiments, we show microsphere migrate along deterministic trajectories toward regions of maximum deviatoric curvature with curvature capillary energies ranging from $6 \\times10^3 - 5 \\times 10^4~k_BT$. These data agree with the curvature capillary energy for the case of pinned contact lines. The underlying physics of this migration is a coupling of the interface deviatoric curvature with the quadrupolar mode of nanometric disturbances in the interface owing to the particle's contact line undulations. This work is an example of the major implications of nanometric roughness and contact line pinning for colloidal dynamics.

  3. Curvature capillary migration of microspheres.

    PubMed

    Sharifi-Mood, Nima; Liu, Iris B; Stebe, Kathleen J

    2015-09-14

    We address the question: how does capillarity propel microspheres along curvature gradients? For a particle on a fluid interface, there are two conditions that can apply at the three phase contact line: either the contact line adopts an equilibrium contact angle, or it can be pinned by kinetic trapping, e.g. at chemical heterogeneities, asperities, or other pinning sites on the particle surface. We formulate the curvature capillary energy for both scenarios for particles smaller than the capillary length and far from any pinning boundaries. The scale and range of the distortion made by the particle are set by the particle radius; we use singular perturbation methods to find the distortions and to rigorously evaluate the associated capillary energies. For particles with equilibrium contact angles, contrary to the literature, we find that the capillary energy is negligible, with the first contribution bounded to fourth order in the product of the particle radius and the deviatoric curvature of the host interface. For pinned contact lines, we find curvature capillary energies that are finite, with a functional form investigated previously by us for disks and microcylinders on curved interfaces. In experiments, we show microspheres migrate along deterministic trajectories toward regions of maximum deviatoric curvature with curvature capillary energies ranging from 6 × 10(3)-5 × 10(4)kBT. These data agree with the curvature capillary energy for the case of pinned contact lines. The underlying physics of this migration is a coupling of the interface deviatoric curvature with the quadrupolar mode of nanometric disturbances in the interface owing to the particle's contact line undulations. This work is an example of the major implications of nanometric roughness and contact line pinning for colloidal dynamics. PMID:26154075

  4. Atmospheric plasma torch treatment of aluminium: Improving wettability with silanes

    NASA Astrophysics Data System (ADS)

    Díaz-Benito, B.; Velasco, F.

    2013-12-01

    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.

  5. Evaluation of Reservoir Wettability and its Effect on Oil Recovery

    SciTech Connect

    Buckley, Jill S.

    1999-11-09

    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.

  6. Methods and preliminary measurement results of liquid Li wettability

    SciTech Connect

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

    2014-02-15

    A test of lithium wettability was performed in high vacuum (< 3 × 10{sup ?4} Pa). High magnification images of Li droplets on stainless steel substrates were produced and processed using the MATLAB{sup ®} 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.

  7. Carbonaceous cathode with enhanced wettability for aluminum production

    DOEpatents

    Keller, Rudolf; Gatty, David G.; Barca, Brian J.

    2003-09-09

    A method of preparing carbonaceous blocks or bodies for use in a cathode in an electrolytic cell for producing aluminum wherein the cell contains an electrolyte and has molten aluminum contacting the cathode, the cathode having improved wettability with molten aluminum. The method comprises the steps of providing a carbonaceous block and a boron oxide containing melt. The carbonaceous block is immersed in the melt and pressure is applied to the melt to impregnate the melt into pores in the block. Thereafter, the carbonaceous block is withdrawn from the melt, the block having boron oxide containing melt intruded into pores therein, the boron oxide capable of reacting with a source of titanium or zirconium or like metal to form titanium or zirconium diboride during heatup or operation of said cell.

  8. Pulmonary capillary pressure. A review.

    PubMed

    Ganter, C C; Ganter, C G; Jakob, S M; Takala, J

    2006-01-01

    Pulmonary capillary pressure (Pcap) is the predominant force that drives fluid out of the pulmonary capillaries into the interstitium. Increasing hydrostatic capillary pressure is directly proportional to the lung's transvascular filtration rate, and in the extreme leads to pulmonary edema. In the pulmonary circulation, blood flow arises from the transpulmonary pressure gradient, defined as the difference between pulmonary artery (diastolic) pressure and left atrial pressure. The resistance across the pulmonary vasculature consists of arterial and venous components, which interact with the capacitance of the compliant pulmonary capillaries. In pathological states such as acute respiratory distress syndrome, sepsis, and high altitude or neurogenic lung edema, the longitudinal distribution of the precapillary arterial and the postcapillary venous resistance varies. Subsequently, the relationship between Pcap and pulmonary artery occlusion pressure (PAOP) is greatly variable and Pcap can no longer be predicted from PAOP. In clinical practice, PAOP is commonly used to guide fluid therapy, and Pcap as a hemodynamic target is rarely assessed. This approach is potentially misleading. In the presence of a normal PAOP and an increased pressure gradient between Pcap and PAOP, the tendency for fluid leakage in the capillaries and subsequent edema development may substantially be underestimated. Tho-roughly validated methods have been developed to assess Pcap in humans. At the bedside, measurement of Pcap can easily be determined by analyzing a pressure transient after an acute pulmonary artery occlusion with the balloon of a Swan-Ganz catheter. PMID:16407804

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  10. Multifunctional commercially pure titanium for the improvement of bone integration: Multiscale topography, wettability, corrosion resistance and biological functionalization.

    PubMed

    Ferraris, Sara; Vitale, Alessandra; Bertone, Elisa; Guastella, Salvatore; Cassinelli, Clara; Pan, Jinshan; Spriano, Silvia

    2016-03-01

    The objects of this research are commercially pure titanium surfaces, with multifunctional behavior, obtained through a chemical treatment and biological functionalization. The explored surfaces are of interest for dental implants, in contact with bone, where several simultaneous and synergistic actions are needed, in order to get a fast and effective osseointegration. The here described modified surfaces present a layer of titanium oxide, thicker than the native one, with a multi-scale surface topography (a surface roughness on the nano scale, which can be overlapped to a micro or macro roughness of the substrate) and a high density of OH groups, that increase surface wettability, induce a bioactive behavior (hydroxyapatite precipitation in simulated body fluid) and make possible the grafting of biomolecules (alkaline phosphatase, ALP, in the present research). The surface oxide is an efficient barrier against corrosion, with passive behavior both with and without application of an external voltage. PMID:26706544

  11. Paramecium swimming in capillary tube

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  12. Small capillary pumped AMTEC systems

    SciTech Connect

    Hunt, T.K.; Sievers, R.K.; Butkiewicz, D.A.; Pantolin, J.E.; Ivanenok, J.F. )

    1993-01-15

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

  13. Stabilizing Fluid-Fluid Displacements in Porous Media Through Wettability Alteration

    E-print Network

    Trojer, Mathias

    We study experimentally how wettability impacts fluid-fluid-displacement patterns in granular media. We inject a low-viscosity fluid (air) into a thin bed of glass beads initially saturated with a more-viscous fluid (a ...

  14. Nonsteady Flow in Capillary Tubes

    NASA Astrophysics Data System (ADS)

    Hara, Ayako

    2000-03-01

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

  15. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

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

    1994-06-28

    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.

  16. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

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

    1996-03-12

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

  17. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

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

    1996-03-12

    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.

  18. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

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

    1994-06-28

    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.

  19. Co-sequestration of SO2 with supercritical CO2 in carbonates: An experimental study of capillary trapping, relative permeability, and capillary pressure

    NASA Astrophysics Data System (ADS)

    Akbarabadi, Morteza; Piri, Mohammad

    2015-03-01

    In this study we performed three categories of steady- and unsteady-state core-flooding experiments to investigate capillary trapping, relative permeability, and capillary pressure, in a scCO2 + SO2/brine/limestone system at elevated temperature and pressure conditions, i.e., 60 °C and 19.16 MPa. We used a Madison limestone core sample acquired from the Rock Springs Uplift in southwest Wyoming. We carried out two sets of steady-state drainage-imbibition relative permeability experiments with different initial brine saturations to study hysteresis. We found that the final scCO2 + SO2 drainage relative permeability was very low, i.e., 0.04. We also observed a rapid reduction in the scCO2-rich phase imbibition relative permeability curve, which resulted in a high residual trapping. The results showed that between 62.8% and more than 76% of the initial scCO2 + SO2 at the end of drainage was trapped by capillary trapping mechanism (trapping efficiency). We found that at higher initial brine saturations, the trapping efficiency was higher. The maximum initial and residual scCO2-rich phase saturations at the end of primary drainage and imbibition were 0.525 and 0.329, respectively. Each drainage-imbibition cycle was followed by a dissolution process to re-establish Sw = 1. The dissolution brine relative permeabilities for both cycles were also obtained. We characterized the scCO2 + SO2/brine capillary pressure hysteresis behavior through unsteady-state primary drainage, imbibition, and secondary drainage experiments. We observed negative imbibition capillary pressure curve indicative of possible wettability alteration throughout the experiments due to contact with scCO2 + SO2/brine fluid system. The trapping results were compared to those reported in literature for other carbonate core samples. We noticed slightly more residual trapping in our sample, which might be attributed to heterogeneity, different viscosity ratio, and pore-space topologies. The impact of dynamic effects, i.e., high brine flow rate imbibition tests, on trapping of the scCO2-rich phase was also explored. We performed two imbibition experiments with relatively high brine flow rates. The residual scCO2 saturation dropped to 0.291 and 0.262 at the end of the first and second imbibition tests, i.e., 11.5% and 20.4%, respectively, compared to 0.329 under capillary-dominated regime.

  20. A Review on the Wettability of Dental Implant Surfaces: Theoretical and Experimental Aspects

    PubMed Central

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

    2014-01-01

    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 on 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

  1. Wettability measurement apparatus for porous material using the modified Washburn method

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    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.

  2. Reduced soil wettability can affect greenhouse gas fluxes

    NASA Astrophysics Data System (ADS)

    Urbanek, Emilia; Qassem, Khalid

    2015-04-01

    Soil moisture is known to be an important factor affecting the carbon (C) dynamics in soils including decomposition of organic matter and exchange of gases like CO2 and CH4 between the soil and the atmosphere. Most studies and process models looking at the soil C dynamics assume, however, that soils are easily wettable and water is relatively uniformly distributed within the soil pores. Most soils, however, do not wet spontaneously when dry or moderately moist, but instead exhibit some degree of soil water repellency (i.e. hydrophobicity), which can restrict infiltration and conductivity of water for weeks or months. This is world-wide occurring phenomenon which affects all soil textural types but is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. Soil water repellency is most profound during drier seasons, when the soil moisture content is relatively low. Although prolonged contact with water can gradually decrease water repellency, some soils do not recover to being completely wettable even after very wet winter months or substantial rainfall events. It has been recognized that with the predicted climatic changes the phenomenon of soil water repellency will become even more pronounced and severe, additionally it may occur in the areas and climatic zones where the effect have not been currently recognized. One of the main implications of soil water repellency is restricted water infiltration and reduced conductivity, which results in reduced soil water availability for plants and soil biota, even after prolonged periods of rainfall. As the process of C mineralization and consequently CO2 efflux from soil is driven by the accessibility of organic matter to decomposing organisms, which in turn is directly dependent on (i) soil moisture and (ii) soil temperature it is, therefore hypothesised that carbon decomposition and CO2 efflux in water repellent soils will also be affected when soil in the water repellent state. The CO2 fluxes will, however, increase once the soil switches to wettable conditions. In a similar way the water repellency affects soil CH4 fluxes favouring the process of oxidation by methanotrophs in water repellent soils. The results of the interdisciplinary study of CH4 and CO2 fluxes from water repellent soils in field and laboratory conditions will be presented. The study sites located in the Netherlands and United Kingdom and include the areas under climatic drought and temperature simulations in the heath-land areas, as well as the sites under natural climatic conditions under grassland and forest land use in the temperate climate. The results available to date provide a strong indication that C mineralization is reduced in water repellent soil, and, given that the total plant biomass in naturally water repellent soil-vegetation systems appears unaffected, this could enhance soil C sequestration on the long term.

  3. Capillary electrophoresis for drug analysis

    NASA Astrophysics Data System (ADS)

    Lurie, Ira S.

    1999-02-01

    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.

  4. Capillary Rise in a Wedge

    ERIC Educational Resources Information Center

    Piva, M.

    2009-01-01

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

  5. Capillary Force between Flexible Filaments.

    PubMed

    Soleimani, Majid; Hill, Reghan J; van de Ven, Theo G M

    2015-08-01

    Liquid droplets bridging filaments are ubiquitous in nature and technology. Although the liquid-surface shape and the capillary force and torque have been studied extensively, the effect of filament flexibility is poorly understood. Here, we show that elastic deformation (at large values of the elasto-capillary number) can significantly affect the liquid-surface shape and capillary force. The equilibrium state of parallel filaments is calculated using analytical approximations and numerical solutions for the fluid interface. The results compare well, and the numerical solution is then applied to crossing filaments. In the investigated range of parameters, the capillary force increases rapidly when the filaments touch. The force decreases continuously when decreasing the liquid volume for parallel hydrophilic filaments but produces a maximum for crossed filaments. The liquid volume at the maximum force is reported when changing the filament flexibility, crossing angle, and contact angle. These results may be beneficial in applications where the strength and structure of wet fibrous materials are important, such as in paper formation and when welding flexible components. PMID:26158380

  6. DNA Sequencing Using capillary Electrophoresis

    SciTech Connect

    Dr. Barry Karger

    2011-05-09

    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

  7. Gradient elution in capillary electrochromatography

    SciTech Connect

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

    1997-08-01

    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.

  8. Capillary filling dynamics of viscoelastic fluids.

    PubMed

    Bandopadhyay, Aditya; Ghosh, Uddipta; Chakraborty, Suman

    2014-05-01

    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. PMID:25353897

  9. Development of functional polymer surfaces with controlled wettability.

    PubMed

    Anastasiadis, Spiros H

    2013-07-30

    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

  10. Manipulated wettability of a superhydrophobic quartz crystal microbalance through electrowetting

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    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.

  12. Development of a Contingency Capillary Wastewater Management Device

    NASA Technical Reports Server (NTRS)

    Thomas, Evan A.

    2010-01-01

    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.

  13. Fluid Delivery System For Capillary Electrophoretic Applications.

    DOEpatents

    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

    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.

  14. Capillary electrophoresis systems and methods

    DOEpatents

    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

    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.

  15. Treelike networks accelerating capillary flow.

    PubMed

    Shou, Dahua; Ye, Lin; Fan, Jintu

    2014-05-01

    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); J. Chen, B. Yu, P. Xu, and Y. Li, Phys. Rev. E 75, 056301 (2007)]. 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. PMID:25353880

  16. Treelike networks accelerating capillary flow

    NASA Astrophysics Data System (ADS)

    Shou, Dahua; Ye, Lin; Fan, Jintu

    2014-05-01

    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.

  17. Determination of Labeled Fatty Acids Content in Milk Products, Infant Formula, and Adult/Pediatric Nutritional Formula by Capillary Gas Chromatography: Single-Laboratory Validation, First Action 2012.13.

    PubMed

    Golay, Pierre-Alain; Dong, Yan

    2015-12-01

    The method described is intended for the quantification of all fatty acids, including commercially important groups of fatty acids used for labeling reasons [i. e., trans fatty acids, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids (PUFA), omega-3, omega-6, and omega-9] and/or individual fatty acids (i. e., linoleic acid, ?-linolenic acid, arachidonic acid, ecosapentaenoic acid, and docosahexaenoic acid) in milk products, infant formula, and adult/pediatric nutritional formula. These products often contain milk fat and/or vegetable oils and are supplemented or not supplemented with oils rich in long-chain PUFA. The determination is performed by direct transesterification of ready-to-feed (RTF) liquid concentrate or powder products without prior fat extraction. Single-laboratory validation (SLV) data were submitted to the AOAC Expert Review Panel (ERP) on Nutrient Methods for review at the AOAC Annual Meeting held on September 30 to October 3, 2012, in Las Vegas, NV. The ERP determined that the data reviewed met the Standard Method Performance Requirements (SMPR(®) 2012.011) set by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) and was approved as an AOAC Official First Action method. The analytical range for SPIFAN samples was between 0.001 and 7.94 g/100 g reconstituted product or RTF liquid. LOQ was estimated as 0.001 g/100 g, while repeatability and intermediate precision were both less than 1.8% RSD above 0.05 g/100 g and <3.5% RSD at 0.005 g/100 g. Recovery values based on spiking experiments at two different levels of linoleic and linolenic acids ranged from 100.0 to 102.9% for three different SPIFAN products. All the parameters evaluated during the SLV were well within the values defined in SMPR 2012.011. PMID:26651581

  18. Wettability of terminally anchored polymer brush layers on a polyamide surface.

    PubMed

    Varin, Kari J Moses; Cohen, Yoram

    2014-12-15

    Surface wettability of terminally anchored hydrophilic polymer brush layers on polyamide-silicon (PA-Si) surfaces was evaluated with respect to surface topography at the nanoscale. Hydrophilic polyvinylpyrrolidone (PVP) and polyacrylamide (PAAm) brush layers were synthesized via graft polymerization onto a PA-Si surface previously activated by surface treatment with atmospheric pressure plasma. Hydrophilicity (or wettability) of the PA substrate, as quantified by the free energy of hydration, was increased upon surface coverage with the PVP and PAAm brush layers by 13-24% (-101.4 to -111.3 mJ/m(2)) and 19-37% (-106.1 to -122.4 mJ/m(2)), respectively. Surface hydrophilicity increased with both increasing surface roughness (0.55-2.89 nm and 1.54-5.84 nm for PVP and PAAm, respectively) and polymer volume (1.3×10(6)-7.3×10(6) nm(3)/?m(2) and 3.3×10(6)-2.8×10(7) nm(3)/?m(2) for PVP and PAAm surfaces, respectively). The present study suggests that a specific level of surface wettability can be attained by tailor-designing the polymer brush layer's physicochemical characteristics (e.g., surface roughness, wettability, and polymer water affinity) by adjusting surface topography and surface chemistry, which are controlled by surface activation and polymerization conditions. The above indicates that there is merit in structuring various surfaces with hydrophilic brush layers to increase surface wettability in membrane filtration, biomedical devices, and lubrication applications. PMID:25305445

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

    PubMed

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

    2009-01-01

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

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

    SciTech Connect

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

    2014-08-28

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

  1. Time dependent wettability of graphite upon ambient exposure: the role of water adsorption.

    PubMed

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

    2014-08-28

    We report the temporal evolution of the wettability of highly ordered pyrolytic graphite (HOPG) exposed to environmental conditions. Macroscopic wettability is investigated by static and dynamic contact angles (SCA and DCA) obtaining values comparable to the ones presented in the literature. SCA increases from ?68° to ?90° during the first hour of exposure after cleaving, whereas DCA is characterized by longer-scale (24 h) time evolution. We interpret these results in light of Fourier transform infrared spectroscopy, which indicates that the evolution of the HOPG wettability is due to adsorption of molecules from the surrounding atmosphere. This hypothesis is further confirmed by nanoscopic observations obtained by atomic force microscope (AFM)-based force spectroscopy, which monitor the evolution of surface properties with a spatial resolution superior to macroscopic experiments. Moreover, we observe that the results of macro- and nanoscale measurements evolve in similar fashion with time and we propose a quantitative correlation between SCA and AFM measurements. Our results suggest that the cause of the transition in the wettability of HOPG is due to the adsorption of hydrocarbon contaminations and water molecules from the environment. This is corroborated by annealing the HOPG is vacuum conditions at 150°, allowing the desorption of molecules on the surface, and thus re-establishing the initial macro and nano surface properties. Our findings can be used in the interpretation of the wettability of more complicated systems derived from HOPG (i.e., graphene). PMID:25173032

  2. Capillary pumped loop body heat exchanger

    NASA Technical Reports Server (NTRS)

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

    1998-01-01

    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.

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

    PubMed

    Ashish Saha, Auro; Mitra, Sushanta K

    2009-11-15

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

  4. Malpighi and the discovery of capillaries.

    PubMed

    Pearce, J M S

    2007-01-01

    Leonardo da Vinci clearly observed and described capillaries. Using the microscope, Marcello Malpighi examined the brain and major organs to demonstrate their finer anatomical features. This led to his discovery in 1661, of capillaries that proved fundamental to our understanding of the vascular system in the brain and cord. He hypothesized that capillaries were the connection between arteries and veins that allowed blood to flow back to the heart in the circulation of the blood, as first asserted by William Harvey. PMID:17851250

  5. Intracranial capillary hemangioma mimicking a dissociative disorder

    PubMed Central

    John, Santosh G.; Pillai, Unnikrishnan; Lacasse, Alexander

    2012-01-01

    Capillary hemangiomas, hamartomatous proliferation of vascular endothelial cells, are rare in the central nervous system (CNS). Intracranial capillary hemangiomas presenting with reversible behavioral abnormalities and focal neurological deficits have rarely been reported. We report a case of CNS capillary hemangioma presenting with transient focal neurological deficits and behavioral abnormalities mimicking Ganser's syndrome. Patient underwent total excision of the vascular malformation, resulting in complete resolution of his symptoms. PMID:24765434

  6. Analysis thermal performance of capillary heat pipe

    NASA Astrophysics Data System (ADS)

    Kosa, Ľuboš; Nemec, Patrik; Malcho, Milan; Jobb, Marián

    2014-08-01

    This work is concentrated on the amount of working fluid for optimization thermal performance of capillary heat pipes. The main objective was to find ideal working fluid for horizontal working position for capillary heat pipes. Working position and amount of working fluid is an important part for function of the heat pipe. Change ideal amount working fluid should be change thermal performance capillary heat pipe.

  7. Capillary Phenomena at Nanoscales: Electrowetting and Capillary Adhesion

    NASA Astrophysics Data System (ADS)

    Robbins, Mark

    2011-11-01

    Theories of capillary phenomena have traditionally been based on continuum approximations that break down as dimensions shrink to nanometer scales. Molecular simulations are used to test the limits of continuum theory in electrowetting on dielectric (EWOD) and capillary adhesion between solids. In EWOD, a fluid drop is separated from an electrode by a dielectric. Increasing the voltage V between drop and electrode, decreases the contact angle ?, allowing the droplet to be manipulated. Simulations of nanoscale drops show the same behavior as experiments on millimeter drops. The contact angle follows the continuum Young-Lippmann equation (YLE) at low voltages and then saturates. The saturation mechanism has been difficult to identify in experiments. Simulations show that charged molecules are pulled from the drop by large electrostatic forces near the contact line. Saturation can be delayed by increasing molecular binding, lowering temperature or increasing dielectric constant. A local force balance equation is derived that agrees with the YLE below saturation and remains valid after saturation. Simulations of capillary adhesion examined the force between a spherical tip of radius R and a flat substrate. The shape of the meniscus agrees remarkably well with continuum theory down to nanometer separations, as does the adhesive force from interfacial tension. However, the total force may deviate by factors of two or have the opposite sign. While the component of the pressure along the substrate agrees with the Laplace pressure from continuum theory, the out-of âplane component does not. There may also be significant force oscillations associated with layering near the solids. The elastic response of the solid has little affect on adhesive forces. This material is based upon work supported by National Science Foundation Grant No. CMS-0103408.

  8. Radial wettable gradient of hot surface to control droplets movement in directions.

    PubMed

    Feng, Shile; Wang, Sijie; Tao, Yuanhao; Shang, Weifeng; Deng, Siyan; Zheng, Yongmei; Hou, Yongping

    2015-01-01

    A radial wettable gradient was fabricated on the surface of graphite plate by a simple one-step anodic oxidation process. It was found that the direction and value of the wettable gradient could be easily controlled by adjusting current and oxidation time gradient. With the increase of surface temperature, droplets on surface not only exhibited the transition of boiling mode, but also showed the controlled radial spreading, evaporation and movement behaviors. These phenomena could be attributed to the cooperation of wettability force, hysteresis force and vapor pressure (Leidenfrost effect). Especially, the controlled radial convergence or divergence of droplets with high velocity were realized on the surfaces with either inside or outside radial gradient, which would have crucial applications in the design of microfluidic devices and the exploration of the biotechnology. PMID:25975722

  9. Radial Wettable Gradient of Hot Surface to Control Droplets Movement in Directions

    PubMed Central

    Feng, Shile; Wang, Sijie; Tao, Yuanhao; Shang, Weifeng; Deng, Siyan; Zheng, Yongmei; Hou, Yongping

    2015-01-01

    A radial wettable gradient was fabricated on the surface of graphite plate by a simple one-step anodic oxidation process. It was found that the direction and value of the wettable gradient could be easily controlled by adjusting current and oxidation time gradient. With the increase of surface temperature, droplets on surface not only exhibited the transition of boiling mode, but also showed the controlled radial spreading, evaporation and movement behaviors. These phenomena could be attributed to the cooperation of wettability force, hysteresis force and vapor pressure (Leidenfrost effect). Especially, the controlled radial convergence or divergence of droplets with high velocity were realized on the surfaces with either inside or outside radial gradient, which would have crucial applications in the design of microfluidic devices and the exploration of the biotechnology. PMID:25975722

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

    SciTech Connect

    Jill S. Buckley; Norman R. Morrow

    2003-05-01

    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.

  11. Wettability influence on the onset temperature of pool boiling: Experimental evidence onto ultra-smooth surfaces.

    PubMed

    Bourdon, B; Bertrand, E; Di Marco, P; Marengo, M; Rioboo, R; De Coninck, J

    2015-07-01

    In this article we study systematically the effect of wettability on the onset of boiling on the same nanometrically smooth surface. By grafting different monolayers of molecules, we were able to explore the wettability from the equilibrium static contact angle, ?0=0° to ?0=110°, without changing the surface topography. The superheat temperature at the onset of pool boiling was measured and eventually a non-classical trend of TONB as a function of wettability was observed. The nucleation site densities for the different grafting cases were also measured by image analysis. Moreover, we propose a novel theoretical interpretation to this phenomenon linking nucleation and the molecular diffusion coefficient. MD simulation results support this approach. PMID:25952077

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

    SciTech Connect

    Aronov, Daniel; Rosenman, Gil; Barkay, Zahava

    2007-04-15

    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.

  13. Radial Wettable Gradient of Hot Surface to Control Droplets Movement in Directions

    NASA Astrophysics Data System (ADS)

    Feng, Shile; Wang, Sijie; Tao, Yuanhao; Shang, Weifeng; Deng, Siyan; Zheng, Yongmei; Hou, Yongping

    2015-05-01

    A radial wettable gradient was fabricated on the surface of graphite plate by a simple one-step anodic oxidation process. It was found that the direction and value of the wettable gradient could be easily controlled by adjusting current and oxidation time gradient. With the increase of surface temperature, droplets on surface not only exhibited the transition of boiling mode, but also showed the controlled radial spreading, evaporation and movement behaviors. These phenomena could be attributed to the cooperation of wettability force, hysteresis force and vapor pressure (Leidenfrost effect). Especially, the controlled radial convergence or divergence of droplets with high velocity were realized on the surfaces with either inside or outside radial gradient, which would have crucial applications in the design of microfluidic devices and the exploration of the biotechnology.

  14. Manipulating surface wettability and oil absorbency of diatomite depending on processing and ambient conditions

    NASA Astrophysics Data System (ADS)

    Özen, ?lhan; ?im?ek, Süleyman; Okyay, Gamze

    2015-03-01

    In this study, a diatomite sample, which is a natural inorganic mineral with inherently high water and oil absorption capacity, was subjected to grinding before surface modification. Afterwards, the diatomite surface was modified via facile methods using a fluorocarbon (FC) chemical and stearic acid (SA) in addition to the sol-gel fluorosilanization (FS) process. The water and oil wettability, and oil absorbency properties of the unmodified and modified diatomites were investigated in addition to diatomite characterizations such as chemical content, surface area, particle size distribution, morphology, and modification efficiency. It was revealed that the wettability was changed completely depending on the surface modification agent and the media used, while the oil absorbency property surprisingly did not change. On the other hand, the oil absorbency was worsened by the grinding process, whereas the wettability was not affected.

  15. Trapping non-wettable fluid in porous rock: Implication to CO2 sequestration

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Yun, T.

    2013-12-01

    The residual saturation of CO2 mainly determines the effective storage capacity in geological formation whereas its transport and fate are dominated by fluid properties and pore characteristics. This experimental study evaluates the relative permeability of brine and non-wettable fluids in Berea sandstone. The surrogate fluids representing CO2 are continuously injected into the brine-saturated sandstone and the effluent is simultaneously separated to measure the residual volume. The variables under consideration include the viscosity and surface tension of injected fluids, porosity, anisotropy of rock, and injection pressure and the residual saturation of non-wettable fluids is quantified based on the proposed variables. Results highlight that the storage capacity can be readily modulated and maximized by controlling the cyclic injection, initial saturation of non-wettable fluids, and injection pressure.

  16. Materials Science and Engineering A245 (1998) 293299 The wettability of silicon carbide by AuSi alloys

    E-print Network

    Grigoriev, Alexei

    1998-01-01

    Materials Science and Engineering A245 (1998) 293­299 The wettability of silicon carbide by Au. Keywords: Wettability; Contact angle; Liquid metals; Silicon carbide 1. Introduction The interface properties of silicon carbide­liquid metals (wetting, adhesion, contact interaction) are im- portant

  17. New concept for coal wettability evaluation and modulation. Technical progress report, April 1, 1994--June 30, 1994

    SciTech Connect

    Hu, W.

    1994-08-01

    This project is concerned with the new concept for coal surface wettability and floatability and modulation. The objective of this work is to study the fundamental surface chemistry features about the evaluation of the surface wettability and floatability of coal and pyrite, and establish a new separation strategy which could contribute to advanced coal-cleaning for premium fuel applications.

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

    E-print Network

    Chung, Deborah D.L.

    EFFECT OF RUST ON THE WETTABILITY OF STEEL BY WATER W. Lu and D.D.L. Chung1 Composite Materials Research Laboratory, State University of New York at Buffalo, Buffalo, NY 14260-4400, USA (Received-carbon steel in water, was found to improve the wettability of steel by water. The advancing contact angle

  19. Transient studies of capillary-induced flow

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    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

  1. Capillary-Gravity Waves Generated by a Slow Moving Object A. D. Chepelianskii,1,2

    E-print Network

    Raphael, Elie

    Capillary-Gravity Waves Generated by a Slow Moving Object A. D. Chepelianskii,1,2 F. Chevy,3 and E are driven by a balance between the liquid inertia and its tendency, under the action of gravity and surface, the dispersion relation relating the angular frequency ! to the wave number k is given by !2 gk k3 =, where

  2. Surface treatment of polymer microfibrillar structures for improved surface wettability and adhesion

    NASA Astrophysics Data System (ADS)

    Peyvandi, Amirpasha; Abideen, Saqib Ul; Huang, Yue; Lee, Ilsoon; Soroushian, Parviz; Lu, Jue

    2014-01-01

    The effects of altering the polymer surface characteristics on adhesion qualities of bio-inspired fibrillar adhesives were found to be significant. Treatment of fibril tip surfaces in polymer fibrillar adhesives improved their wettability and adhesion capacity. Surface modifications of fibril tips involved UV/Ozone and oxygen plasma treatments for making the fibril tips more hydrophilic. These surface treatment effects, however, tend to degrade over time (rendering hydrophobic recovery). The stability of treated (hydrophilic) surfaces was improved, while retaining their wettability, through coating with a polyelectrolyte such as polyethyleneimine (PEI) via self-assembly.

  3. CO2 -Responsive Nanofibrous Membranes with Switchable Oil/Water Wettability.

    PubMed

    Che, Hailong; Huo, Meng; Peng, Liao; Fang, Tommy; Liu, Na; Feng, Lin; Wei, Yen; Yuan, Jinying

    2015-07-27

    Responsive polymer interfacial materials are ideal candidates for controlling surface wetting behavior. Here we developed smart nanostructured electrospun polymer membranes which are capable of switching oil/water wettability using CO2 as the trigger. In particular, the combination of CO2 -responsiveness and porous nanostructure enables the as-prepared membranes to be used as a novel oil/water on-off switch. We anticipate that the promising versatility and simplicity of this system would not only open up a new way of surface wettability change regulation by gas, but also have obvious advantages in terms of highly controlled oil/water separation and CO2 applications. PMID:26079643

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

    SciTech Connect

    Jill S. Buckley; Norman R. Morrow

    2006-01-01

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

  5. Pharmacological effects of various venoms on cutaneous capillary leakage.

    PubMed

    Burnett, J W; Calton, G J

    1986-01-01

    Studies to counteract the cutaneous vasopermeability actions of a wasp (Vespa orientalis), an anemone (Bolocera tuediae) and three jellyfish (Chironex fleckeri, Chrysaora quinquecirrha and Physalia physalis) venoms were conducted by using various pharmacological antagonists. Piripost (a leukotriene inhibitor) reduced vasopermeability if administered 5 min prior to challenge with the jellyfish venoms. Methysergide counteracted the vasopermeability of three of four coelenterate venoms, whereas indomethacin was effective against capillary leakage induced by Chironex venom. These studies indicate that anti-dermonecrotic therapy against various venoms will have to be species-specific. PMID:2875548

  6. 21 CFR 864.6150 - Capillary blood collection tube.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

  7. Microfoam formation in a capillary.

    PubMed

    Kotopoulis, Spiros; Postema, Michiel

    2010-02-01

    The ultrasound-induced formation of bubble clusters may be of interest as a therapeutic means. If the clusters behave as one entity, i.e., one mega-bubble, its ultrasonic manipulation towards a boundary is straightforward and quick. If the clusters can be forced to accumulate to a microfoam, entire vessels might be blocked on purpose using an ultrasound contrast agent and a sound source. In this paper, we analyse how ultrasound contrast agent clusters are formed in a capillary and what happens to the clusters if sonication is continued, using continuous driving frequencies in the range 1-10 MHz. Furthermore, we show high-speed camera footage of microbubble clustering phenomena. We observed the following stages of microfoam formation within a dense population of microbubbles before ultrasound arrival. After the sonication started, contrast microbubbles collided, forming small clusters, owing to secondary radiation forces. These clusters coalesced within the space of a quarter of the ultrasonic wavelength, owing to primary radiation forces. The resulting microfoams translated in the direction of the ultrasound field, hitting the capillary wall, also owing to primary radiation forces. We have demonstrated that as soon as the bubble clusters are formed and as long as they are in the sound field, they behave as one entity. At our acoustic settings, it takes seconds to force the bubble clusters to positions approximately a quarter wavelength apart. It also just takes seconds to drive the clusters towards the capillary wall. Subjecting an ultrasound contrast agent of given concentration to a continuous low-amplitude signal makes it cluster to a microfoam of known position and known size, allowing for sonic manipulation. PMID:19875143

  8. Altering Reservoir Wettability to Improve Production from Single Wells

    SciTech Connect

    W. W. Weiss

    2006-09-30

    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.

  9. High pressure pulsed capillary viscometry

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    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.

  10. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    SciTech Connect

    Wang, Chenchen; Tang, Keqi; Smith, Richard D.

    2014-06-17

    A sheathless interface for coupling capillary electrophoresis (CE) with mass spectrometry is disclosed. The sheathless interface includes a separation capillary for performing CE separation and an emitter capillary for electrospray ionization. A portion of the emitter capillary is porous or, alternatively, is coated to form an electrically conductive surface. A section of the emitter capillary is disposed within the separation capillary, forming a joint. A metal tube, containing a conductive liquid, encloses the joint.

  11. Ash wettability conditions splash erosion in the postfire

    NASA Astrophysics Data System (ADS)

    Gordillo-Rivero, Ángel J.; de Celis, Reyes; García-Moreno, Jorge; Jiménez-Compán, Elizabeth; Alanís, Nancy; Cerdà, Artemi; Pereira, Paulo; Zavala, Lorena M.; Jordán, Antonio

    2015-04-01

    1. INTRODUCTION Soil sustainability and recovery after fire depend on physical, chemical and biological processes and fire severity (Neary et al., 1999; Mataix-Solera and Guerrero, 2007). Fire effects on soils are divided in two types: direct effects, as a consequence of combustion and temperature reached and indirect effects (Neary et al., 1999) as consequence of changes in other ecosystem components, such as decrease in vegetal coverage or ash and partially burned litter contribution including changes in flora (Pausas and Verdú, 2005; Trabaud, 2000). Low intensity fires, during which high temperatures are not reached, affect vegetal coverage but will not cause major impacts on soil. In contrast, prolonged, recurrent, or high-intensity fires may cause important impacts on the soil system functioning (De Celis et al., 2013; DeBano, 1991; Mataix-Solera et al., 2009; Zavala et al., 2014), aggregation (Mataix-Solera et al., 2011), organic matter content and quality (Sevink et al., 1989), water repellency (DeBano, 2000; Doerr et al., 2000), soil nutrients (Stark, 1977), soil erosion (Larsen et al., 2009) and others. In these cases, the restoration period of the initial conditions can be very long and changes may become permanent (DeBano, 1991). During combustion, fuel (biomass, necromass and soil organic matter) is transformed in materials with new physical and chemical properties. After burn, the soil surface is covered by a layer of ash and charred organic residues. Ash has important ecological, hydrological and geomorphological effects, even after being rearranged or mobilized by runoff or wind (Bodí et al., 2014). Ash properties will depend on the burned species, the amount of affected biomass, fuel flammability and structure, temperature and the residence time of thermal peaks (Pereira et al., 2009). Some studies have emphasized the role of ash on soil protection during the after fire period, in which the vegetable coverage could be drastically decreased (Cerdà and Doerr, 2008; Woods and Balfour, 2008; Zavala et al., 2009). The presence of an ash layer may be ephemeral, as it often is quickly removed or redistributed by water and wind erosion, animals or traffic (Zavala et al., 2009a). Many authors have observed that the capacity of ash to protect soil depends on properties as the topography, the meteorological conditions and the thickness of ash coverage (Cerdà and Doerr, 2008; Pereira et al., 2013; Woods and Balfour, 2010; Zavala et al., 2009). Taking this into account, in this study we hypothesized that the wettability / hydrophobicity of the ash layer may have a significant effect on the soil response to splash erosion. Therefore, the aim of this study is to evaluate the dispersion of sediments produced by the impact of raindrops in function of ash wettability after a prescribed fire at plot scale. 2. MATERIAL AND METHODS In 20 November 2012, a prescribed fire was carried out in an area located in the public mount "Las Navas", near Almaden de la Plata, Sevilla (approx. 37° 50' 44.44'' N / 6° 3' 7.44''W and 428 masl). Soils are acidic and shallow, developed from acidic metamorphic rocks (schists, slates and pyrophyllites). Vegetation is dominated by shrub legumes (Calicotome villosa and several species of Ulex and Genista). The experimental area was framed and plowed to eliminate the risk of fire spreading during the experiment. Previously to burn, level staffs were installed for determination of flame height. The temperature reached in the soil was monitored during the fire by a set of six thermocouples which were buried in soil (2 cm depth) and connected to a data-logger for monitoring the topsoil temperature every 60 s. The environmental conditions were also monitored during the experiment by a mobile weather station. At the moment of the ignition, the temperature was around 20 °C and the wind speed was near 0.0 m/s. After ignition, the experimental area was allowed to burn during 2.5 h. During burning, flames reached 200 cm height, although thermal peaks recorded 2 cm depth were relatively low (n

  12. Capillary gas chromatography of lupin alkaloids.

    PubMed

    Priddis, C R

    1983-05-20

    The resolution and identification of twelve lupin alkaloids are demonstrated using capillary gas chromatography and gas chromatography-mass spectrometry. The quantitative capabilities of capillary gas chromatography are illustrated by specific reference to the four major alkaloids of lupinus angustifolius, namely lupanine, 13-hydroxylupanine, augustifoline and alpha-isolupanine. PMID:6874800

  13. Capillary Physiology and Drug Delivery in Central

    E-print Network

    Timmer, Jens

    Capillary Physiology and Drug Delivery in Central Nervous System Lymphomas Peter C. Warnke, MD,1 drug delivery, we quantita- tively assessed pharmacokinetic factors in seven patients. The capillary the chemosensitivity of primary cen- tral nervous system lymphomas to water-soluble drugs could result from improved

  14. Patch Clamp Detection in Capillary Electrophoresis

    E-print Network

    Articles Patch Clamp Detection in Capillary Electrophoresis Kent Jardemark Department of Anatomy a capillary electrophoresis-patch clamp (CE- PC) analysis of biomolecules that activate ligand-gated ion responses were calculated from currents recorded with patch clamp detection. This information

  15. Streptomycetes can grow through small filter capillaries.

    PubMed

    Wolf, H; Schoppmann, H

    1989-02-01

    Streptomycetes are Gram-positive bacteria growing as branching filaments. The filaments are able to deform. This ability allows the cells to squeeze through capillaries as small as 0.2 micron in diameter. After passage through the capillaries, numerous hyphae are morphologically altered to a helical structure. PMID:2721918

  16. Gravity Capillary Standing Water Waves Pietro Baldi

    E-print Network

    Thomann, Laurent

    Gravity Capillary Standing Water Waves Pietro Baldi Universit`a di Napoli Federico II Joint work with Thomas Alazard (ENS Paris) Pienza, 29 October 2014 Pietro Baldi Gravity Capillary Standing Water Waves, with gravity and capillarity (WW) t = G() t = -g - 1 2 2 x + (G() + xx)2 2(1 + 2 x) + xx (1 + 2 x)3/2 We

  17. Influence of pore morphology and topology on capillary trapping in geological carbon dioxide sequestration

    NASA Astrophysics Data System (ADS)

    Andersson, L.; Harper, E.; Herring, A. L.; Wildenschild, D.

    2012-12-01

    Current carbon capture and storage (CCS) techniques could reduce the release of anthropogenic CO2 into the atmosphere by subsurface sequestration of CO2 in saline aquifers. In geological storage CO2 is injected into deep underground porous formations where CO2 is in the supercritical state. 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, dissolution, and precipitation 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 CO2 moves upwards, trapping a large part of the CO2. This trapping mechanism is known as capillary trapping and occurs as isolated CO2 bubbles are locked in the brine inside the pores of the porous rock. The large-scale movement of CO2 within the brine is thereby prevented. This mechanism thus constitutes an important storage mechanism after the CO2 injection until the subsequent dissolution trapping and precipitation of carbonate mineral. The capillary trapping of CO2 depends largely on the shape and interconnectivity of the pore space and it is therefore important to study the influence of pore scale morphology and topology to understand and optimize large scale capillary trapping. We use a high pressure set-up, designed for supercritical CO2 conditions, with a flow cell compatible with synchrotron-based X-ray computed micro-tomography (CMT) to generate high-resolution images to study capillary trapping. We use sintered glass bead columns as an approximation for unconsolidated reservoir systems. The smooth surface glass bead data allow us to separate the chemistry and surface roughness effects of the porous medium from the effect of the morphology and topology on the capillary trapping. We will relate these aspects of the pore space to the distribution of the fluids (wetting and non-wetting) and initial and residual non-wetting phase saturations. Potential wettability alteration due to exposure of the beads to supercritical CO2 is also explored by comparing high-pressure and low-pressure experimental results.

  18. Evaluation of capillary reinforced composites

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  19. Intracranial capillary hemangioma in an elderly patient

    PubMed Central

    Okamoto, Ai; Nakagawa, Ichiro; Matsuda, Ryosuke; Nishimura, Fumihiko; Motoyama, Yasushi; Park, Young-Su; Nakamura, Mitsutoshi; Nakase, Hiroyuki

    2015-01-01

    Background: Capillary hemangiomas are neoplasms involving skin and soft tissue in infants. These lesions rarely involved an intracranial space and reported age distribution ranges from infancy to middle age. We report an extremely rare case of rapidly rising intracranial capillary hemangioma in an elderly woman. Case Description: The 82-year-old woman presented with vomiting, reduced level of consciousness, and worsening mental state. Computed tomography showed a contrast-enhanced extra-axial lesion in the left frontal operculum, although no intracranial mass lesion was identifiable from magnetic resonance imaging taken 2 years earlier. Complete surgical excision was performed and histopathological examination diagnosed benign capillary hemangioma consisting of a variety of dilated capillary blood vessels lined by endothelial cells. Conclusion: This is the first description of rapid growth of an intracranial capillary hemangioma in an elderly woman. These lesions are exceedingly rare in the elderly population, but still show the capacity for rapid growth. Complete excision would prevent further recurrence. PMID:26664868

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

    PubMed Central

    Lin, Meng C.; Svitova, Tatyana F.

    2010-01-01

    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. PMID:20400924

  1. Surfactant and Irrigation Effects on Runoff, Erosion, and Water Retention of Three Wettable Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surfactants are chemical compounds that change the contact angle of water on solid surfaces and are commonly used to increase infiltration into hydrophobic soil. Since production fields with water-repellent soil often contain areas of wettable soil, surfactants applied to such fields will likely be ...

  2. The Effect Of Viscoelastic Surfactants Used In Carbonate Matrix Acidizing On Wettability 

    E-print Network

    Adejare, Oladapo

    2012-07-16

    on wettability. In a previous study using contact angle experiments, it was reported that spent acid solutions with VES only, and with VES and EGMBE are water-wetting. In this thesis, we studied the effect of two amphoteric amine-oxide VES', designated as "A...

  3. Surface roughness and wettability of dentin ablated with ultrashort pulsed laser

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Lü, Peijun; Sun, Yuchun; Wang, Yong

    2015-05-01

    The aim of this study was to evaluate the surface roughness and wettability of dentin following ultrashort pulsed laser ablation with different levels of fluence and pulse overlap (PO). Twenty-five extracted human teeth crowns were cut longitudinally into slices of approximately 1.5-mm thick and randomly divided into nine groups of five. Samples in groups 1 to 8 were ablated with an ultrashort pulsed laser through a galvanometric scanning system. Samples in group 9 were prepared using a mechanical rotary instrument. The surface roughness of samples from each group was then measured using a three-dimensional profile measurement laser microscope, and wettability was evaluated by measuring the contact angle of a drop of water on the prepared dentin surface using an optical contact angle measuring device. The results showed that both laser fluence and PO had an effect on dentin surface roughness. Specifically, a higher PO decreased dentin surface roughness and reduced the effect of high-laser fluence on decreasing the surface roughness in some groups. Furthermore, all ablated dentin showed a contact angle of approximately 0 deg, meaning that laser ablation significantly improved wettability. Adjustment of ultrashort pulsed laser parameters can, therefore, significantly alter dentin surface roughness and wettability.

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

    E-print Network

    Cao, Guozhong

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

  5. Investigation of wettability by NMR microscopy and spin-lattice relaxation

    SciTech Connect

    Doughty, D.A.; Tomutsa, Liviu

    1993-11-01

    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.

  6. Wettability of graphitic-carbon and silicon surfaces: MD modeling and theoretical analysis

    NASA Astrophysics Data System (ADS)

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G. P.

    2015-07-01

    The wettability of graphitic carbon and silicon surfaces was numerically and theoretically investigated. A multi-response method has been developed for the analysis of conventional molecular dynamics (MD) simulations of droplets wettability. The contact angle and indicators of the quality of the computations are tracked as a function of the data sets analyzed over time. This method of analysis allows accurate calculations of the contact angle obtained from the MD simulations. Analytical models were also developed for the calculation of the work of adhesion using the mean-field theory, accounting for the interfacial entropy changes. A calibration method is proposed to provide better predictions of the respective contact angles under different solid-liquid interaction potentials. Estimations of the binding energy between a water monomer and graphite match those previously reported. In addition, a breakdown in the relationship between the binding energy and the contact angle was observed. The macroscopic contact angles obtained from the MD simulations were found to match those predicted by the mean-field model for graphite under different wettability conditions, as well as the contact angles of Si(100) and Si(111) surfaces. Finally, an assessment of the effect of the Lennard-Jones cutoff radius was conducted to provide guidelines for future comparisons between numerical simulations and analytical models of wettability.

  7. Wettability of graphitic-carbon and silicon surfaces: MD modeling and theoretical analysis.

    PubMed

    Ramos-Alvarado, Bladimir; Kumar, Satish; Peterson, G P

    2015-07-28

    The wettability of graphitic carbon and silicon surfaces was numerically and theoretically investigated. A multi-response method has been developed for the analysis of conventional molecular dynamics (MD) simulations of droplets wettability. The contact angle and indicators of the quality of the computations are tracked as a function of the data sets analyzed over time. This method of analysis allows accurate calculations of the contact angle obtained from the MD simulations. Analytical models were also developed for the calculation of the work of adhesion using the mean-field theory, accounting for the interfacial entropy changes. A calibration method is proposed to provide better predictions of the respective contact angles under different solid-liquid interaction potentials. Estimations of the binding energy between a water monomer and graphite match those previously reported. In addition, a breakdown in the relationship between the binding energy and the contact angle was observed. The macroscopic contact angles obtained from the MD simulations were found to match those predicted by the mean-field model for graphite under different wettability conditions, as well as the contact angles of Si(100) and Si(111) surfaces. Finally, an assessment of the effect of the Lennard-Jones cutoff radius was conducted to provide guidelines for future comparisons between numerical simulations and analytical models of wettability. PMID:26233153

  8. Femtosecond laser induced hierarchical ZnO superhydrophobic surfaces with switchable wettability.

    PubMed

    Yong, Jiale; Chen, Feng; Yang, Qing; Fang, Yao; Huo, Jinglan; Hou, Xun

    2015-06-18

    A simple and one-step method to form a rough ZnO layer consisting of micro/nanoscale hierarchical structures via direct femtosecond laser ablation of the Zn surface is reported for the first time. The resultant surfaces show switchable wettability between superhydrophobicity and quasi-superhydrophilicity via alternate UV irradiation and dark storage. PMID:25987485

  9. Polymer membrane with a mineral coating for enhanced curling resistance and surface wettability.

    PubMed

    Yang, Hao-Cheng; Chen, Yi-Fu; Ye, Chen; Jin, Yi-Ning; Li, Hanying; Xu, Zhi-Kang

    2015-08-18

    Zirconia-wrapped membranes were fabricated via a mineralization process on polydopamine/polyethyleneimine-deposited surfaces. The rigid and hydrophilic mineral coating simultaneously endows the membranes with enhanced curling resistance and surface wettability, enabling the membranes to separate oil-in-water emulsions. PMID:26166831

  10. Figure 1. Schematic of the manipulation of the graphene surface wettability via strain engineering.[3

    E-print Network

    Pennycook, Steve

    of the isobaric and isothermal thermodynamic response functions of the aqueous phase, and significant slowdown grown epitaxially on silicon carbide single crystal surfaces, probed by contact wetting angle resulted in significant changes not only on the surface wettability, but also in the isothermal

  11. Influence of the wettability on the electrical response of microporous systems

    NASA Astrophysics Data System (ADS)

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

    2000-05-01

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

  12. Altering Wettability in Gas Condensate Sandstone Reservoirs for Gas Mobillity Improvement 

    E-print Network

    Fernandez Martinez, Ruth Gabriela

    2012-07-16

    Christine Ehlig-Economides Committee Member, Maria Barrufet Head of Department, Steve Holditch May 2011 Major Subject: Petroleum Engineering iii? ? ? ABSTRACT Altering Wettability in Gas Condensate.... Christine Ehlig-Economides In gas-condensate reservoirs, production rate starts to decrease when retrograde condensation occurs. As the bottomhole pressure drops below the dewpoint, gas- condensate and water buildup impede flow of gas to the surface...

  13. Multifunctional superamphiphobic TiO2 nanostructure surfaces with facile wettability and adhesion engineering.

    PubMed

    Huang, Jian-Ying; Lai, Yue-Kun; Pan, Fei; Yang, Lei; Wang, Hui; Zhang, Ke-Qin; Fuchs, Harald; Chi, Li-Feng

    2014-12-10

    Compared to conventional top-down photo-cleavage method, a facile bottom-up ink-combination method to in situ and rapidly achieve water wettability and adhesion transition, with a great contrast on the superamphiphobic TiO2 nanostructured film, is described. Moreover, such combination method is suitable for various kinds of superamphiphobic substrate. Oil-based ink covering or removing changes not only the topographical morphology but also surface chemical composition, and these resultant topographical morphology and composition engineering realize the site-selectively switchable wettability varying from superamphiphobicity to amphiphilicity, and water adhesion between sliding superamphiphobicity and sticky superamphiphobicity in micro-scale. Additionally, positive and negative micro-pattern can be achieved by taking advantage of the inherent photocatalytic property of TiO2 with the assistance of anti-UV light ink mask. Finally, the potential applications of the site-selectively sticky superamphiphobic surface were demonstrated. In a proof-of-concept study, the microdroplet manipulation (storage, moving, mixing, and transfer), specific gas sensing, wettability template for positive and negative ZnO patterning, and site-selective cell immobilization have been demonstrated. This study will give an important input to the field of advanced functional material surfaces with special wettability. PMID:25070619

  14. Surfactant and irrigation effects on wettable soils: Runoff, erosion, and water retention responses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surfactants are chemical compounds that change the contact angle of water on solid surfaces and are commonly used to increase infiltration into hydrophobic soil. Since production fields with water-repellent soil often contain areas of wettable soil, surfactants applied to such fields will likely be ...

  15. Effect of surface wettability on carbon nanotube water-based nanofluid droplet impingement heat transfer

    NASA Astrophysics Data System (ADS)

    Jackson, Robert Gordon; Kahani, Mostafa; Karwa, Nitin; Wu, Alex; Lamb, Robert; Taylor, Robert; Rosengarten, Gary

    2014-07-01

    Recent studies into droplet impingement heat transfer have demonstrated that it has great potential for providing high heat flux cooling in areas such as thermal management of electronics. The wettability of the surface affects the flow dynamics of the impingement process and the resulting heat transfer. In this study, the effect of surface wettability on carbon nanotube water-based nanofluid droplet impingement heat transfer has been studied and compared with water. Superhydrophobic or hydrophilic coatings are applied on one face of monocrystalline silicon wafers (the drop impinges on this face) while the other face is painted matt black to permit infrared thermography. The silicon wafer is preheated to 40 °C and a single droplet impinges normally on the top facing coated surface of the monocrystalline silicon wafer. The inverse heat conduction problem has been solved using the measured black face temperature. For both the water and nanofluid droplets, the convective heat transfer coefficient reduces with the decrease in surface wettability. It is found that the nanofluid produce a significantly higher convective heat transfer coefficient during droplet impingement than water, with the enhancement increasing with increasing wettability.

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

    E-print Network

    Torres-Verdín, Carlos

    water to become mobile, with the percentage of additional movable water depending on both type of mud-filtrate. Sharma and Wunderlich (1985) studied wettability alterations due to water-base mud-filtrate invasion less oil-wet after becoming in contact with water-base mud- filtrate. Later, Menezes et al (1989

  17. Water-entry value as an alternative indicator of soil water-repellency and wettability

    E-print Network

    Dundas, Robert G.

    Water-entry value as an alternative indicator of soil water-repellency and wettability Z. Wang*, L, 1969). Three drops of distilled water from a standard medicine dropper are placed on the smoothed as an alternative indicator of soil water-repellency. By first imposing a low hydraulic pressure at the soil surface

  18. A Goniometric Microscope to Quantify Feather Structure, Wettability, and Resistance to Liquid Penetration

    E-print Network

    1 A Goniometric Microscope to Quantify Feather Structure, Wettability, and Resistance to Liquid plastron film) within the microstructures of their feathers. In addition, many species within the family and wing spreading are related to feather structure, extensive microscopy and photographic studies have

  19. Novel Convenient Method to Determine Wettability and Dispersibility of Dairy Powders

    PubMed Central

    Park, Dong June; Lim, Kwangsei

    2014-01-01

    This study was carried out to develop a simple, convenient, and reproducible testing device to determine wettability and dispersibility of dairy powders. The testing device consists of a sieve (150 ?m) attached to a sample chamber, sensors mounted on a supporting body and a main control unit containing a display panel. The sensors detect the difference in electrical resistance between air and water. A timer is automatically triggered by the sensor when the bottom of sample-loaded chamber contacts water in the petri dish. Wettability and dispersibility of commercial skim milk powders (SMPs) produced at different heating strengths (low-, medium-, and high-heat SMP) are compared using the new testing device. Wettability of the SMPs were correlated with particle size and are found to increase in the order of medium-, low-, and high-heat SMP regardless of the amount of sample tested. Dispersibility of SMPs showed the same trend and high heat-SMP which has the smallest particle size resulted in the lowest dispersibility. Unlike existing methods, the new testing device can determine both wettability and dispersibility of powders and successfully detected differences among the samples.

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

    NASA Astrophysics Data System (ADS)

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

    2011-06-01

    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.

  1. Technology Solutions Case Study: Capillary Break Beneath a Slab: Polyethylene Sheeting over Aggregate, Southwestern Pennsylvania

    SciTech Connect

    2014-07-01

    In this project, Building America team IBACOS worked with a builder of single- and multifamily homes in southwestern Pennsylvania (climate zone 5) to understand its methods of successfully using polyethylene sheeting over aggregate as a capillary break beneath the slab in new construction. This builder’s homes vary in terms of whether they have crawlspaces or basements. However, in both cases, the strategy protects the home from water intrusion via capillary action (e.g., water wicking into cracks and spaces in the slab), thereby helping to preserve the durability of the home.

  2. Wettability measurement under high P-T conditions using X-ray imaging with application to the brine-supercritical CO2 system

    NASA Astrophysics Data System (ADS)

    Chaudhary, Kuldeep; Guiltinan, Eric J.; Cardenas, M. Bayani; Maisano, Jessica A.; Ketcham, Richard A.; Bennett, Philip C.

    2015-09-01

    We present a new method for measuring wettability or contact angle of minerals at reservoir pressure-temperature conditions using high-resolution X-ray computed tomography (HRXCT) and radiography. In this method, a capillary or a narrow slot is constructed from a mineral or a rock sample of interest wherein two fluids are allowed to form an interface that is imaged using X-rays. After some validation measurements at room pressure-temperature conditions, we illustrate this method by measuring the contact angle of CO2-brine on quartz, muscovite, shale, borosilicate glass, polytetrafluoroethylene (PTFE or Teflon), and polyether ether ketone (PEEK) surfaces at 60-71°C and 13.8-22.8 MPa. At reservoir conditions, PTFE and PEEK surfaces were found to be CO2-wet with contact angles of 140° and 127°, respectively. Quartz and muscovite were found to be water-wet with contact angles of 26° and 58°, respectively, under similar conditions. Borosilicate glass-air-brine at room conditions showed strong water-wet characteristics with a contact angle of 9°, whereas borosilicate glass-CO2-brine at 13.8 MPa and 60°C showed a decrease in its water-wetness with contact angle of 54°. This method provides a new application for X-ray imaging and an alternative to other methods.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

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

    SciTech Connect

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

    1993-09-01

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

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

    SciTech Connect

    Norman R. Morrow; Jill Buckley

    2006-04-01

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

  6. New concept for coal wettability evaluation and modulation. Technical progress report, January 1, 1994--March 31, 1994

    SciTech Connect

    Hu, W.

    1994-05-01

    This project is concerned with the new concept for coal surface wettability and floatability evaluation and modulation. During this quarter the Hallimond-tube tests were conducted for the three coals, mineral pyrite, and coal pyrite samples. The kinetic floatability of the five samples have been tested without collector, with kerosene and with benzene as collector. The test results indicate that there are good agreements between the experimental observation and the theoretical assumption hypothesis about the new concept of the surface wettability and floatability of the coal and pyrite. These test results also shown that wettability is incompatible with floatability.

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

    PubMed Central

    2011-01-01

    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. PMID:21711852

  8. Two-dimensional capillary origami

    NASA Astrophysics Data System (ADS)

    Brubaker, N. D.; Lega, J.

    2016-01-01

    We describe a global approach to the problem of capillary origami that captures all unfolded equilibrium configurations in the two-dimensional setting where the drop is not required to fully wet the flexible plate. We provide bifurcation diagrams showing the level of encapsulation of each equilibrium configuration as a function of the volume of liquid that it contains, as well as plots representing the energy of each equilibrium branch. These diagrams indicate at what volume level the liquid drop ceases to be attached to the endpoints of the plate, which depends on the value of the contact angle. As in the case of pinned contact points, three different parameter regimes are identified, one of which predicts instantaneous encapsulation for small initial volumes of liquid.

  9. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

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

    2005-08-09

    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.

  10. Gravity Capillary Standing Water Waves

    NASA Astrophysics Data System (ADS)

    Alazard, Thomas; Baldi, Pietro

    2015-09-01

    The paper deals with the 2D gravity-capillary water waves equations in their Hamiltonian formulation, addressing the question of the nonlinear interaction of a plane wave with its reflection off a vertical wall. The main result is the construction of small amplitude, standing (namely periodic in time and space, and not travelling) solutions of Sobolev regularity, for almost all values of the surface tension coefficient, and for a large set of time-frequencies. This is an existence result for a quasi-linear, Hamiltonian, reversible system of two autonomous pseudo-PDEs with small divisors. The proof is a combination of different techniques, such as a Nash-Moser scheme, microlocal analysis and bifurcation analysis.

  11. Towards new applications using capillary waveguides.

    PubMed

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-12-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 ?m-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 ?m-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 ?m beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  12. Towards new applications using capillary waveguides

    PubMed Central

    Stasio, Nicolino; Shibukawa, Atsushi; Papadopoulos, Ioannis N.; Farahi, Salma; Simandoux, Olivier; Huignard, Jean-Pierre; Bossy, Emmanuel; Moser, Christophe; Psaltis, Demetri

    2015-01-01

    In this paper we demonstrate the enhancement of the sensing capabilities of glass capillaries. We exploit their properties as optical and acoustic waveguides to transform them potentially into high resolution minimally invasive endoscopic devices. We show two possible applications of silica capillary waveguides demonstrating fluorescence and optical-resolution photoacoustic imaging using a single 330 ?m-thick silica capillary. A nanosecond pulsed laser is focused and scanned in front of a capillary by digital phase conjugation through the silica annular ring of the capillary, used as an optical waveguide. We demonstrate optical-resolution photoacoustic images of a 30 ?m-thick nylon thread using the water-filled core of the same capillary as an acoustic waveguide, resulting in a fully passive endoscopic device. Moreover, fluorescence images of 1.5 ?m beads are obtained collecting the fluorescence signal through the optical waveguide. This kind of silica-capillary waveguide together with wavefront shaping techniques such as digital phase conjugation, paves the way to minimally invasive multi-modal endoscopy. PMID:26713182

  13. Transcapillary Exchange in Relation to Capillary Circulation

    PubMed Central

    Renkin, Eugene M.

    1968-01-01

    Transcapillary exchange of diffusible solutes depends on capillary blood flow, Q; capillary permeability, P; and capillary surface area, S. In a single capillary, the extent of equilibration of a given solute depends on the ratio of Q, to the product of P and S. In a microvascular bed consisting of many capillaries, equilibration depends on the fraction of them which are open to blood flow at any time and on the distribution of Q/PS ratios in the open capillaries. Both these characteristics are subject to control by vascular smooth muscle, particularly by the precapillary sphincters. Vasomotor mechanisms have been shown experimentally to exert a wide range of effective control over blood-tissue transport. In skeletal muscle, effective PS measured with 42K or 86Rb may be increased 8-fold from maximum nervous vasoconstriction to optimum metabolic vasodilatation. Most probably, these changes are due to differences in functional capillary surface area and of blood flow distribution relative to permeability and surface area. The extent to which variations in permeability itself can contribute to control of transcapillary exchange is not known. PMID:19873630

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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.

  15. Arrested segregative phase separation in capillary tubes.

    PubMed

    Tromp, R Hans; Lindhoud, Saskia

    2006-09-01

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

  16. Micromechanism linear actuator with capillary force sealing

    DOEpatents

    Sniegowski, Jeffry J. (Albuquerque, NM)

    1997-01-01

    A class of micromachine linear actuators whose function is based on gas driven pistons in which capillary forces are used to seal the gas behind the piston. The capillary forces also increase the amount of force transmitted from the gas pressure to the piston. In a major subclass of such devices, the gas bubble is produced by thermal vaporization of a working fluid. Because of their dependence on capillary forces for sealing, such devices are only practical on the sub-mm size scale, but in that regime they produce very large force times distance (total work) values.

  17. Photopolymerized Sol-Gel Monoliths for Capillary Electrochromatography

    E-print Network

    Zare, Richard N.

    Photopolymerized Sol-Gel Monoliths for Capillary Electrochromatography Maria T. Dulay, Joselito P.d. capillary to prepare a porous monolithic sol-gel column by a one-step, in situ, process. The photopoly fabrication problems, surface-functionalized open-tubular capillary columns6,8-10 and monolithic capillaries6

  18. A single-probe capillary microgripper induced by dropwise condensation and inertial release

    NASA Astrophysics Data System (ADS)

    Fan, Zenghua; Rong, Weibin; Wang, Lefeng; Sun, Lining

    2015-11-01

    A micromanipulation method based on liquid droplets is widely used as a non-destructive technology to pick-and-place micrometer-scale objects. We focus on the development of a single-probe capillary microgripper to execute reliable micromanipulation tasks. By controlling dropwise condensation on a probe tip, the water droplet volume on the hydrophobic tip surface can be varied dynamically, which helps establish appropriate capillary lifting forces during capturing tasks. An inertia-releasing strategy was utilized to implement a piezoelectric actuator integrated with the capillary microgripper and to address release problems caused by adhesion force action. The influence of droplet formation and the capillary lifting force generated during the manipulation process were characterized experimentally. Micromanipulation tests were conducted using a customized motion platform with viewing microscopes to verify the performance potential of the capillary microgripping tool. Experimental results indicated that polystyrene microspheres with 20-100 ?m radii and micro-silicon chips (1.63-12.1 ?N) were grasped reliably, and that adhered micro-objects could be placed on a target using the proposed microhandling technique of inertial release in ambient conditions.

  19. Capillary electrochromatography using fibers as stationary phases.

    PubMed

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

    2001-10-01

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

  20. CAPILLARY BARRIERS IN UNSATURATED FRACTURED ROCKS

    SciTech Connect

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

    2000-10-01

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

  1. Capillary pressure in fractured porous media

    SciTech Connect

    Flroozabadl, A. ); Hauge, J. )

    1990-06-01

    In a proposed phenomenological model for fracture capillary pressure, the fracture faces are assumed to be covered with cones, each of which contacts the tip of an opposing cone. Cones in contact at the tip represent both roughness and aperture of a fracture surface. The solution to the Young--Laplace equation of capillarity is used to relate fracture capillary pressure {ital P}{sub c} to saturation. The computed {ital P}{sub c}/saturation results show a porous-medium behavior for fracture capillary pressure. Experiments with a stack of small matrix blocks in a centrifuge produced final measured production rates and matrix-block saturations that confirm the validity of the porous-medium model for fracture capillary pressure.

  2. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A. (Santa Fe, NM)

    1980-01-01

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

  3. 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...

  4. Two phase flow in capillary tubes

    E-print Network

    Suo, Mikio

    1963-01-01

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

  5. Capillary flow of dense colloidal suspensions 

    E-print Network

    Isa, Lucio

    2008-01-01

    The purpose of this thesis is to study the flow of dense colloidal suspensions into micronsized capillaries at the particle level. Understanding the flow of complex fluids in terms of their constituents (colloids, ...

  6. Thin film capillary process and apparatus

    DOEpatents

    Yu, Conrad M.

    2003-11-18

    Method and system of forming microfluidic capillaries in a variety of substrate materials. A first layer of a material such as silicon dioxide is applied to a channel etched in substrate. A second, sacrificial layer of a material such as a polymer is deposited on the first layer. A third layer which may be of the same material as the first layer is placed on the second layer. The sacrificial layer is removed to form a smooth walled capillary in the substrate.

  7. Capillary Movement in Substrates in Microgravity

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    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.

  8. Capillary interactions in nano-particles suspensions

    NASA Astrophysics Data System (ADS)

    Bossev, Dobrin; Warren, Garfield

    2010-03-01

    We have investigated the structures formed by colloidal particles suspended in solvents at volume fractions below 10% and interacting through capillary bridges. Such systems resemble colloidal gas of sticky nano-spheres that form pearl-necklace like chains that, in turn, induce strong viscoleasticity due to the formation of 3-D fractal network. The capillary force dominates the electrostatic and Van der Waals forces in solutions and can bridge multiple particles depending of the volume of the capillary bridge. Small-angle neutron scattering (SANS) is used to study nanoparticles with an average diameter of 10 nm in polar and non-polar organic solvents at ambient temperatures. Computer simulations of a pearl necklace-like chain of spheres is conducted to explain the structure factor when capillary bridges are present. We have also studied the properties of the capillary bridge between a pair of particles. The significance of this study is to explore the possibility of using capillary force as a tool to engineer new colloidal structures and materials in solutions and to optimize their viscoelastic properties.

  9. Capillary interactions in nano-particles suspensions

    NASA Astrophysics Data System (ADS)

    Bossev, Dobrin; Warren, Garfield

    2009-03-01

    We have investigated the structures formed by colloidal particles suspended in solvents at volume fractions below 10% and interacting through capillary bridges. Such systems resemble colloidal gas of sticky nano-spheres that form pearl-necklace like chains that, in turn, induce strong viscoleasticity due to the formation of 3-D fractal network. The capillary force dominates the electrostatic and Van der Waals forces in solutions and can bridge multiple particles depending of the volume of the capillary bridge. We have investigated the morphology of the structures formed at different fractions of the bridging fluid. Computer simulations of a pearl necklace-like chain of spheres is conducted to explain the structure factor when capillary bridges are present. Alternatively, we have analyzed the slope of the neutron scattering intensity at low Q in a double logarithmic plot to determine the dimension of the fractal structures formed by the particles at different volume fraction of the bridging fluid. We have also studied the properties of the capillary bridge between a pair of particles. The significance of this study is to explore the possibility of using capillary force as a tool to engineer new colloidal structures and materials in solutions and to optimize their viscoelastic properties.

  10. Multiple capillary biochemical analyzer with barrier member

    SciTech Connect

    Dovichi, Norman J.; Zhang, Jian Z.

    1996-01-01

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

  11. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

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

    1996-10-22

    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.

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

    PubMed

    Chang, Jean H; Hunter, Ian W

    2011-05-18

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

  13. Correlation between surface properties and wettability of multi-scale structured biocompatible surfaces

    NASA Astrophysics Data System (ADS)

    Gorodzha, S. N.; Surmeneva, M. A.; Prymak, O.; Wittmar, A.; Ulbricht, M.; Epple, M.; Teresov, A.; Koval, N.; Surmenev, R. A.

    2015-11-01

    The influence of surface properties of radio-frequency (RF) magnetron deposited hydroxyapatite (HA) and Si-containing HA coatings on wettability was studied. The composition and morphology of the coatings fabricated on titanium (Ti) were characterized using atomic force microscopy (AFM) and X-ray diffraction (XRD). The surface wettability was studied using contact angle analysis. Different geometric parameters of acid-etched (AE) and pulse electron beam (PEB)-treated Ti substrates and silicate content in the HA films resulted in the different morphology of the coatings at micro- and nano- length scales. Water contact angles for the HA coated Ti samples were evaluated as a combined effect of micro roughness of the substrate and nano-roughness of the HA films resulting in higher water contact angles compared with acid-etched (AE) or pulse electron beam (PEB) treated Ti substrates.

  14. Wettability Stabilizes Fluid Invasion into Porous Media via Nonlocal, Cooperative Pore Filling

    NASA Astrophysics Data System (ADS)

    Holtzman, Ran; Segre, Enrico

    2015-10-01

    We study the impact of the wetting properties on the immiscible displacement of a viscous fluid in disordered porous media. We present a novel pore-scale model that captures wettability and dynamic effects, including the spatiotemporal nonlocality associated with interface readjustments. Our simulations show that increasing the wettability of the invading fluid (the contact angle) promotes cooperative pore filling that stabilizes the invasion and that this effect is suppressed as the flow rate increases, due to viscous instabilities. We use scaling analysis to derive two dimensionless numbers that predict the mode of displacement. By elucidating the underlying mechanisms, we explain classical yet intriguing experimental observations. These insights could be used to improve technologies such as hydraulic fracturing, CO2 geosequestration, and microfluidics.

  15. Molecular Dynamic Approach of Enhanced Self-Propelled Nano-Droplet Motion on Wettability Gradient Surfaces

    E-print Network

    Chakraborty, Monojit; Bhusan, Richa; DasGupta, Sunando

    2015-01-01

    Droplet motion over a surface with wettability gradient has been simulated using molecular dynamics (MD) simulation to highlight the underlying physics. GROMACS and Visual Molecular Dynamics (VMD) were used for simulation and intermittent visualization of the droplet configuration respectively. The simulations mimic experiments in a comprehensive manner wherein micro-sized droplets are propelled by surface wettability gradient against a number of retarding forces. The liquid-wall Lennard-Jones interaction parameter and the substrate temperature were varied to explore their effects on the three-phase contact line friction coefficient. The contact line friction was observed to be a strong function of temperature at atomistic scales, confirming the experimentally observed inverse functionality between the coefficient of contact line friction and increase in temperatures. These MD simulation results were successfully compared with the results from a model for self-propelled droplet motion on gradient surfaces.

  16. Molecular Dynamics Study of Thermally Augmented Nanodroplet Motion on Chemical Energy Induced Wettability Gradient Surfaces.

    PubMed

    Chakraborty, Monojit; Chowdhury, Anamika; Bhusan, Richa; DasGupta, Sunando

    2015-10-20

    Droplet motion on a surface with chemical energy induced wettability gradient has been simulated using molecular dynamics (MD) simulation to highlight the underlying physics of molecular movement near the solid-liquid interface including the contact line friction. The simulations mimic experiments in a comprehensive manner wherein microsized droplets are propelled by the surface wettability gradient against forces opposed to motion. The liquid-wall Lennard-Jones interaction parameter and the substrate temperature are varied to explore their effects on the three-phase contact line friction coefficient. The contact line friction is observed to be a strong function of temperature at atomistic scales, confirming their experimentally observed inverse functionality. Additionally, the MD simulation results are successfully compared with those from an analytical model for self-propelled droplet motion on gradient surfaces. PMID:26381847

  17. Molecular Dynamic Approach of Enhanced Self-Propelled Nano-Droplet Motion on Wettability Gradient Surfaces

    E-print Network

    Monojit Chakraborty; Anamika Chowdhury; Richa Bhusan; Sunando DasGupta

    2015-04-10

    Droplet motion over a surface with wettability gradient has been simulated using molecular dynamics (MD) simulation to highlight the underlying physics. GROMACS and Visual Molecular Dynamics (VMD) were used for simulation and intermittent visualization of the droplet configuration respectively. The simulations mimic experiments in a comprehensive manner wherein micro-sized droplets are propelled by surface wettability gradient against a number of retarding forces. The liquid-wall Lennard-Jones interaction parameter and the substrate temperature were varied to explore their effects on the three-phase contact line friction coefficient. The contact line friction was observed to be a strong function of temperature at atomistic scales, confirming the experimentally observed inverse functionality between the coefficient of contact line friction and increase in temperatures. These MD simulation results were successfully compared with the results from a model for self-propelled droplet motion on gradient surfaces.

  18. Wettability stabilizes fluid invasion into porous media via nonlocal, cooperative pore filling

    E-print Network

    Holtzman, Ran

    2015-01-01

    We study the impact of the wetting properties on the immiscible displacement of a viscous fluid in disordered porous media. We present a novel pore-scale model that captures wettability and dynamic effects, including the spatiotemporal nonlocality associated with interface readjustments. Our simulations show that increasing the wettability of the invading fluid (the contact angle) promotes cooperative pore filling that stabilizes the invasion, and that this effect is suppressed as the flow rate increases, due to viscous instabilities. We use scaling analysis to derive two dimensionless numbers that predict the mode of displacement. By elucidating the underlying mechanisms, we explain classical yet intriguing experimental observations. These insights could be used to improve technologies such as hydraulic fracturing, CO$_{2}$ geo-sequestration, and microfluidics.

  19. Wettability stabilizes fluid invasion into porous media via nonlocal, cooperative pore filling

    E-print Network

    Ran Holtzman; Enrico Segre

    2015-09-15

    We study the impact of the wetting properties on the immiscible displacement of a viscous fluid in disordered porous media. We present a novel pore-scale model that captures wettability and dynamic effects, including the spatiotemporal nonlocality associated with interface readjustments. Our simulations show that increasing the wettability of the invading fluid (the contact angle) promotes cooperative pore filling that stabilizes the invasion, and that this effect is suppressed as the flow rate increases, due to viscous instabilities. We use scaling analysis to derive two dimensionless numbers that predict the mode of displacement. By elucidating the underlying mechanisms, we explain classical yet intriguing experimental observations. These insights could be used to improve technologies such as hydraulic fracturing, CO$_{2}$ geo-sequestration, and microfluidics.

  20. Tunable Surface Wettability of ZnO Nanoparticle Arrays for Controlling the Alignment of Liquid Crystals.

    PubMed

    Chung, Yueh-Feng; Chen, Mu-Zhe; Yang, Sheng-Hsiung; Jeng, Shie-Chang

    2015-05-13

    The control of the liquid crystal (LC) alignment is very important for both academic research and practical applications. LC molecules aligned on the ZnO nanoparticle arrays (ZnO NPAs) are demonstrated and the pretilt angles of LCs can be controlled by using ZnO NPAs with different surface wettability. The wettability of ZnO NPAs fabricated by the solution-based hydrothermal method can be controlled by changing the annealing temperature of the as-prepared ZnO NPAs. The measurements of the energy-dispersive spectra and photoluminescence have shown that the chemical properties of ZnO NPAs have been changed with the annealing temperature. Our results show that the pretilt angle of LCs can be tuned continuously from ?0 to ?90° as the contact angle of water on ZnO NPAs changes from 33 to 108°. PMID:25895105

  1. Wettability Stabilizes Fluid Invasion into Porous Media via Nonlocal, Cooperative Pore Filling.

    PubMed

    Holtzman, Ran; Segre, Enrico

    2015-10-16

    We study the impact of the wetting properties on the immiscible displacement of a viscous fluid in disordered porous media. We present a novel pore-scale model that captures wettability and dynamic effects, including the spatiotemporal nonlocality associated with interface readjustments. Our simulations show that increasing the wettability of the invading fluid (the contact angle) promotes cooperative pore filling that stabilizes the invasion and that this effect is suppressed as the flow rate increases, due to viscous instabilities. We use scaling analysis to derive two dimensionless numbers that predict the mode of displacement. By elucidating the underlying mechanisms, we explain classical yet intriguing experimental observations. These insights could be used to improve technologies such as hydraulic fracturing, CO_{2} geosequestration, and microfluidics. PMID:26550879

  2. Capillary fracture of soft gels

    E-print Network

    Bostwick, Joshua B

    2013-01-01

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

  3. Capillary fracture of soft gels

    E-print Network

    Joshua B. Bostwick; Karen E. Daniels

    2013-10-16

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

  4. Nonlinear waves in capillary electrophoresis

    PubMed Central

    Ghosal, Sandip; Chen, Zhen

    2011-01-01

    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care and forensics. In capillary electrophoresis the sample migrates in a microcapillary in the presence of a background electrolyte. When the ionic concentration of the sample is sufficiently high, the signal is known to exhibit features reminiscent of nonlinear waves including sharp concentration ‘shocks’. In this paper we consider a simplified model consisting of a single sample ion and a background electrolyte consisting of a single co-ion and a counterion in the absence of any processes that might change the ionization states of the constituents. If the ionic diffusivities are assumed to be the same for all constituents the concentration of sample ion is shown to obey a one dimensional advection diffusion equation with a concentration dependent advection velocity. If the analyte concentration is sufficiently low in a suitable non-dimensional sense, Burgers’ equation is recovered, and thus, the time dependent problem is exactly solvable with arbitrary initial conditions. In the case of small diffusivity either a leading edge or trailing edge shock is formed depending on the electrophoretic mobility of the sample ion relative to the background ions. Analytical formulas are presented for the shape, width and migration velocity of the sample peak and it is shown that axial dispersion at long times may be characterized by an effective diffusivity that is exactly calculated. These results are consistent with known observations from physical and numerical simulation experiments. PMID:20238181

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

    SciTech Connect

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

    2014-04-24

    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.

  6. On the enhancement of probability of ion induced nucleation on partially wettable, water insoluble planar substrate

    NASA Astrophysics Data System (ADS)

    Singh, N.; Rai, J.; Varshneya, N. C.

    1990-06-01

    The nucleating behavior of partially wettable, water insoluble planar substrate has been studied. The rate and probability of nucleation were found to be enhanced in ion induced nucleation. It is found that there exists a threshold for angle of contact above which the effect of ions is dominant. The effect of ions is more pronounced at low supersaturation ratios and low temperatures for the material of large angle of contact w.r.t. water.

  7. Contact angles and wettability of ionic liquids on polar and non-polar surfaces.

    PubMed

    Pereira, Matheus M; Kurnia, Kiki A; Sousa, Filipa L; Silva, Nuno J O; Lopes-da-Silva, José A; Coutinho, João A P; Freire, Mara G

    2015-11-25

    Many applications involving ionic liquids (ILs) require the knowledge of their interfacial behaviour, such as wettability and adhesion. In this context, herein, two approaches were combined aiming at understanding the impact of the IL chemical structures on their wettability on both polar and non-polar surfaces, namely: (i) the experimental determination of the contact angles of a broad range of ILs (covering a wide number of anions of variable polarity, cations, and cation alkyl side chain lengths) on polar and non-polar solid substrates (glass, Al-plate, and poly-(tetrafluoroethylene) (PTFE)); and (ii) the correlation of the experimental contact angles with the cation-anion pair interaction energies generated by the Conductor-like Screening Model for Real Solvents (COSMO-RS). The combined results reveal that the hydrogen-bond basicity of ILs, and thus the IL anion, plays a major role through their wettability on both polar and non-polar surfaces. The increase of the IL hydrogen-bond accepting ability leads to an improved wettability of more polar surfaces (lower contact angles) while the opposite trend is observed on non-polar surfaces. The cation nature and alkyl side chain lengths have however a smaller impact on the wetting ability of ILs. Linear correlations were found between the experimental contact angles and the cation-anion hydrogen-bonding and cation ring energies, estimated using COSMO-RS, suggesting that these features primarily control the wetting ability of ILs. Furthermore, two-descriptor correlations are proposed here to predict the contact angles of a wide variety of ILs on glass, Al-plate, and PTFE surfaces. A new extended list is provided for the contact angles of ILs on three surfaces, which can be used as a priori information to choose appropriate ILs before a given application. PMID:26554705

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

    SciTech Connect

    Jill S. Buckley; Norman R. Morrow

    2005-04-01

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

  9. New concept for coal wettability evaluation and modulation. Technical progress report, April 1--June 30, 1995

    SciTech Connect

    Hu, W.

    1996-05-01

    The objective of this project is to evaluate the surface wettability and flotation of coal and pyrite in order to establish a new separation strategy for advanced coal cleaning for premium fuel applications. During this quarter, mini-cell flotation tests were carried out on Upper Freeport, Pittsburgh No. 8, and Illinois No. 6 coals, and two pyrite samples. Flotation media used were kerosene, benzene, and amyl-xanthate. Test results are given and discussed.

  10. Wettability and Coalescence of Cu Droplets Subjected to Two-Wall Confinement

    NASA Astrophysics Data System (ADS)

    Li, Xiongying; Ren, Hongru; Wu, Weikang; Li, Hui; Wang, Long; He, Yezeng; Wang, Junjun; Zhou, Yi

    2015-10-01

    Controlling droplet dynamics via wettability or movement at the nanoscale is a significant goal of nanotechnology. By performing molecular dynamics simulations, we study the wettability and spontaneous coalescence of Cu droplets confined in two carbon walls. We first focus on one drop in the two-wall confinement to reveal confinement effects on wettability and detaching behavior of metallic droplets. Results show that Cu droplets finally display three states: non-detachment, semi-detachment and full detachment, depending on the height of confined space. The contact angle ranges from 125° to 177°, and the contact area radius ranges from 12 to ~80?Å. The moving time of the detached droplet in the full detachment state shows a linear relationship with the height of confined space. Further investigations into two drops subjected to confinement show that the droplets, initially distant from each other, spontaneously coalesce into a larger droplet by detachment. The coalescing time and final position of the merged droplet are precisely controlled by tailoring surface structures of the carbon walls, the height of the confined space or a combination of these approaches. These findings could provide an effective method to control the droplet dynamics by confinement.

  11. Switchable Wettability of the Honeybee’s Tongue Surface Regulated by Erectable Glossal Hairs

    PubMed Central

    Chen, Ji; Wu, Jianing; Yan, Shaoze

    2015-01-01

    Various nectarivorous animals apply bushy-hair-equipped tongues to lap nectar from nectaries of flowers. A typical example is provided by the Italian honeybee (Apis mellifera ligustica), who protracts and retracts its tongue (glossa) through a temporary tube, and actively controls the erectable glossal hairs to load nectar. We first examined the microstructure of the honeybee’s glossal surface, recorded the kinematics of its glossal hairs during nectar feeding process and observed the rhythmical hair erection pattern clearly. Then we measured the wettability of the glossal surface under different erection angles (EA) in sugar water of the mass concentration from 25 to 45%, mimicked by elongating the glossa specimens. The results show that the EA in retraction approximately remains stable under different nectar concentrations. In a specific concentration (35, 45, or 55%), the contact angle decreases and glossal surface area increases while the EA of glossal hairs rises, the glossa therefore could dynamically alter the glossal surface and wettability in foraging activities, not only reducing the energy consumption for impelling the nectar during tongue protraction, but also improving the nectar-trapping volume for feeding during glossa retraction. The dynamic glossal surface with switchable wettability regulated by erectable hairs may reveal the effective adaptation of the honeybee to nectar intake activities. PMID:26643560

  12. Switchable Wettability of the Honeybee's Tongue Surface Regulated by Erectable Glossal Hairs.

    PubMed

    Chen, Ji; Wu, Jianing; Yan, Shaoze

    2015-01-01

    Various nectarivorous animals apply bushy-hair-equipped tongues to lap nectar from nectaries of flowers. A typical example is provided by the Italian honeybee (Apis mellifera ligustica), who protracts and retracts its tongue (glossa) through a temporary tube, and actively controls the erectable glossal hairs to load nectar. We first examined the microstructure of the honeybee's glossal surface, recorded the kinematics of its glossal hairs during nectar feeding process and observed the rhythmical hair erection pattern clearly. Then we measured the wettability of the glossal surface under different erection angles (EA) in sugar water of the mass concentration from 25 to 45%, mimicked by elongating the glossa specimens. The results show that the EA in retraction approximately remains stable under different nectar concentrations. In a specific concentration (35, 45, or 55%), the contact angle decreases and glossal surface area increases while the EA of glossal hairs rises, the glossa therefore could dynamically alter the glossal surface and wettability in foraging activities, not only reducing the energy consumption for impelling the nectar during tongue protraction, but also improving the nectar-trapping volume for feeding during glossa retraction. The dynamic glossal surface with switchable wettability regulated by erectable hairs may reveal the effective adaptation of the honeybee to nectar intake activities. PMID:26643560

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

    PubMed Central

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

    2005-01-01

    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. PMID:16849215

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

    PubMed

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

    2006-02-22

    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

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

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

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

  16. Laser surface modification of AZ31B?Mg alloy for bio-wettability.

    PubMed

    Ho, Yee-Hsien; Vora, Hitesh D; Dahotre, Narendra B

    2015-02-01

    Magnesium alloys are the potential degradable materials for load-bearing implant application due to their comparable mechanical properties to human bone, excellent bioactivity, and in vivo non-toxicity. However, for a successful load-bearing implant, the surface of bio-implant must allow protein absorption and layer formation under physiological environment that can assist the cell/osteoblast growth. In this regard, surface wettability of bio-implant plays a key role to dictate the quantity of protein absorption. In light of this, the main objective of the present study was to produce favorable bio-wettability condition of AZ31B Mg alloy bio-implant surface via laser surface modification technique under various laser processing conditions. In the present efforts, the influence of laser surface modification on AZ31B Mg alloy surface on resultant bio-wettability was investigated via contact-angle measurements and the co-relationships among microstructure (grain size), surface roughness, surface energy, and surface chemical composition were established. In addition, the laser surface modification technique was simulated by computational (thermal) model to facilitate the prediction of temperature and its resultant cooling/solidification rates under various laser processing conditions for correlating with their corresponding composition and phase evolution. These predicted thermal properties were later used to correlate with the corresponding microstructure, chemical composition, and phase evolution via experimental analyses (X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy). PMID:25201909

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

    SciTech Connect

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

    1988-01-01

    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.

  18. Wettability and Coalescence of Cu Droplets Subjected to Two-Wall Confinement

    PubMed Central

    Li, Xiongying; Ren, Hongru; Wu, Weikang; Li, Hui; Wang, Long; He, Yezeng; Wang, Junjun; Zhou, Yi

    2015-01-01

    Controlling droplet dynamics via wettability or movement at the nanoscale is a significant goal of nanotechnology. By performing molecular dynamics simulations, we study the wettability and spontaneous coalescence of Cu droplets confined in two carbon walls. We first focus on one drop in the two-wall confinement to reveal confinement effects on wettability and detaching behavior of metallic droplets. Results show that Cu droplets finally display three states: non-detachment, semi-detachment and full detachment, depending on the height of confined space. The contact angle ranges from 125° to 177°, and the contact area radius ranges from 12 to ~80?Å. The moving time of the detached droplet in the full detachment state shows a linear relationship with the height of confined space. Further investigations into two drops subjected to confinement show that the droplets, initially distant from each other, spontaneously coalesce into a larger droplet by detachment. The coalescing time and final position of the merged droplet are precisely controlled by tailoring surface structures of the carbon walls, the height of the confined space or a combination of these approaches. These findings could provide an effective method to control the droplet dynamics by confinement. PMID:26459952

  19. Tuning the surface wettability of carbon nanotube carpets in multiscale hierarchical solids

    NASA Astrophysics Data System (ADS)

    Karumuri, Anil K.; He, Lvmeng; Mukhopadhyay, Sharmila M.

    2015-02-01

    An attractive approach of increasing functionality of solid surfaces is to create hierarchical multiscale morphology by attaching tailored carpet-like arrays of Carbon nanotubes (CNT) on them. Such surfaces offer fractal morphology along with unprecedented increase in specific surface areas, and significantly boost the potency of porous materials used in surface-active applications. However, full utilization of these structures will require intimate interaction between the solid surface and its environmental fluid. CNT arrays tend to be hydrophobic, which limit their effectiveness in aqueous environments. In this research, we investigated two different surface modifications methods to induce hydrophilic property to CNT nano-carpets on graphitic substrates: dry oxygen plasma treatment and wet sol-gel oxide coating. Structure, morphology, composition and chemistry of these multiscale surfaces have been related to wettability and water flow properties. Plasma oxygen treatments did not alter the surface morphology, but induced temporary wettability, that could be reversed by heat treatment. On the other hand, sol-gel treatment permanently coated the nanotubes with a strongly bonded layer of amorphous SiO2. This coating imparts permanent alterations in surface chemistry, contact angle, wettability and water flow. Porous carbon foams were coated with CNT arrays and their water permeability measured before and after sol-gel silica coating. The hydrophilic coating was seen to increase flow rate and reduce pressure build-up. These results have important implications on all devices that utilize surface activity of porous solids, such as catalytic membranes, antimicrobial filters, and microfluidic sensors.

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

    PubMed Central

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

    2014-01-01

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

  1. Effects of wettability and pore-level displacement on hydrocarbon trapping

    NASA Astrophysics Data System (ADS)

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

    2008-03-01

    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.

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

    SciTech Connect

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

    2006-09-01

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

  3. Improved wettability of an experimental silicone rubber denture soft lining material.

    PubMed

    Waters, M; Jagger, R

    1999-01-01

    The purpose of this study was to improve the wettability of an experimental silicone rubber soft lining material (Sildent) to increase patient comfort. Sildent was modified by the addition of polyalkylene oxide poly(dimethylsiloxane) surfactants. The various surfactants were added directly to the polymeric matrix in the quantities 5, 10, 20% w/w. The surfactants were also added to a one part silicone sealant, which was then painted onto the surface of already cured Sildent. Contact angle measurements were made on samples using a dynamic contact angle analyzer. Results showed that incorporation of surfactants A (Silwet L7600) and B (Silwet L7607) effectively improved the wettability of Sildent. This improvement was still evident after 6 months storage in distilled water at 37 degrees C suggesting retention of the surfactants matrix via physio-chemical bonding. Formulations with surfactants added directly to the matrix showed unacceptable water absorption after 2 months in distilled water. Samples with surfactant charged sealant painted on the surface showed a lower water absorption. In conclusion, Sildent formulations modified with polyalkylene silicone surfactants showed improved wettability compared to unmodified Sildent. Further work is needed to reduce water uptake and determine the effect on key mechanical properties. PMID:10556838

  4. Supercritical CO2 and Ionic Strength Effects on Wettability of Silica Surfaces: Equilibrium Contact Angle Measurements

    SciTech Connect

    Jung, J. W.; Wan, Jiamin

    2012-09-20

    Wettability of reservoir mineral surfaces is a critical factor controlling CO{sub 2} mobility, trapping, and safe-storage in geological carbon sequestration. Although recent studies have begun to show that wettability of some minerals can change in the presence of supercritical CO{sub 2} (scCO{sub 2}), different laboratories have reported significantly different wetting behavior. We studied wettability alteration of silica in CO{sub 2}–brine systems through measuring equilibrium water contact angles under wide ranges of pressures (0.1 to 25 MPa) and ionic strengths (0 to 5.0 M NaCl), at 45 °C. Using two independent approaches for each of the experiments, we found the following: (1) Equilibrium water contact angles on silica increased up to 17.6° ± 2.0° as a result of reactions with scCO{sub 2}. This increase occurred primarily within the pressure range 7–10 MPa, and the contact angles remain nearly constant at pressure greater than 10 MPa. (2) The contact angle increased with ionic strength nearly linearly, with a net increase of 19.6° ± 2.1° at 5.0 M NaCl. These changes in contact angle induced by changes in scCO{sub 2} pressure and aqueous solution ionic strength are approximately additive over the range of tested conditions. These findings can be used to estimate the wetting behavior of silica surfaces in reservoirs containing supercritical CO{sub 2}.

  5. A Review on the Wettability of Dental Implant Surfaces II: Biological and Clinical Aspects

    PubMed Central

    Gittens, Rolando A.; Scheideler, Lutz; Rupp, Frank; Hyzy, Sharon L.; Geis-Gerstorfer, Jürgen; Schwartz, Zvi; Boyan, Barbara D.

    2014-01-01

    Dental and orthopaedic implants have been under continuous advancement to improve their interactions with bone and ensure a successful outcome for patients. Surface characteristics such as surface topography and surface chemistry can serve as design tools to enhance the biological response around the implant, with in vitro, in vivo and clinical studies confirming their effects. However, the comprehensive design of implants to promote early and long-term osseointegration requires a better understanding of the role of surface wettability and the mechanisms by which it affects the surrounding biological environment. This review provides a general overview of the available information about the contact angle values of experimental and of marketed implant surfaces, some of the techniques used to modify surface wettability of implants, and results from in vitro and clinical studies. We aim to expand the current understanding on the role of wettability of metallic implants at their interface with blood and the biological milieu, as well as with bacteria, and hard and soft tissues. PMID:24709541

  6. Carbonic anhydrase--a marker for fenestrated capillaries in psoriasis.

    PubMed

    Jungkunz, W; Eichhorn, M; Wörl, J; Marsch, W C; Holzmann, H

    1992-01-01

    A strong correlation between capillary fenestrations and the demonstration of carbonic anhydrase (CA) has previously been shown. In the present histochemical study we sought to determine whether CA could serve as a marker for fenestrated capillaries in psoriasis. In normal human skin capillary staining for CA was found only in the fenestrated capillaries of the perifollicular and periglandular plexus. In psoriatic skin lesions, however, the intrapapillary capillaries also reacted for CA. From ultrastructural investigations it is known that these capillaries are fenestrated. Our findings have shown that there is a strong correlation between fenestrated and CA-positive capillaries in normal human skin as well as in the lesional skin of psoriatics. Therefore, the demonstration of CA activity may serve as a specific and sensitive marker for fenestrated capillaries in psoriasis using an uncomplicated method, which makes it possible to detect numerous fenestrated capillaries in a single histological section. PMID:1503498

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

    SciTech Connect

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

    1992-01-01

    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)

  8. Micro-injector for capillary electrophoresis.

    PubMed

    Sáiz, Jorge; Koenka, Israel Joel; García-Ruiz, Carmen; Müller, Beat; Chwalek, Thomas; Hauser, Peter C

    2015-08-01

    A novel micro-injector for capillary electrophoresis for the handling of samples with volumes down to as little as 300 nL was designed and built in our laboratory for analyses in which the available volume is a limitation. The sample is placed into a small cavity located directly in front of the separation capillary, and the injection is then carried out automatically by controlled pressurization of the chamber with compressed air. The system also allows automated flushing of the injection chamber as well as of the capillary. In a trial with a capillary electrophoresis system with contactless conductivity detector, employing a capillary of 25 ?m diameter, the results showed good stability of migration times and peak areas. To illustrate the technique, the fast separation of five inorganic cations (Na(+) , K(+) , NH4 (+) , Ca(2+) , and Mg(2+) ) was set up. This could be achieved in less than 3 min, with good limits of detection (10 ?M) and linear ranges (between about 10 and 1000 ?M). The system was demonstrated for the determination of the inorganic cations in porewater samples of a lake sediment core. PMID:25752271

  9. Modeling aerobic biodegradation in the capillary fringe.

    PubMed

    Luo, Jian; Kurt, Zohre; Hou, Deyi; Spain, Jim C

    2015-02-01

    Vapor intrusion from volatile subsurface contaminants can be mitigated by aerobic biodegradation. Laboratory column studies with contaminant sources of chlorobenzene and a mixture of chlorobenzene, 1,2-dichlorobenzene, and 1,4-dichlorobenzene showed that contaminants were rapidly degraded in thin reactive zones with high biomass and low substrate concentrations in the vicinity of the capillary fringe. Such behavior was well characterized by a model that includes oxygen-, substrate-, and biomass-dependent biodegradation kinetics along with diffusive transport processes. An analytical solution was derived to provide theoretical support for the simplification of reaction kinetics and the approximation of reactive zone location and mass flux relationships at steady state. Results demonstrate the potential of aerobic natural attenuation in the capillary fringe for preventing contaminant migration in the unsaturated zone. The solution indicates that increasing contaminant mass flux into the column creates a thinner reactive zone and pushes it toward the oxygen boundary, resulting in a shorter distance to the oxygen source and a larger oxygen mass flux that balances the contaminant mass flux. As a consequence, the aerobic biodegradation can reduce high contaminant concentrations to low levels within the capillary fringe and unsaturated zone. The results are consistent with the observations of thin reactive layers at the interface in unsaturated zones. The model considers biomass while including biodegradation in the capillary fringe and unsaturated zone and clearly demonstrates that microbial communities capable of using the contaminants as electron donors may lead to instantaneous degradation kinetics in the capillary fringe and unsaturated zone. PMID:25548946

  10. EUV radiation from nitrogen capillary discharge

    NASA Astrophysics Data System (ADS)

    Frolov, Oleksandr; Kolacek, Karel; Schmidt, Jiri; Straus, Jaroslav

    2014-08-01

    In the last decade EUV sources attract interest from researchers over the world. One of the main motivations is EUV lithography, which could lead to further miniaturization in electronics. Nitrogen recombination laser at wavelength of 13.4 nm based on capillary discharge Z-pinch configuration could be used in experiments with testing of resolution of photoresist for EUV lithography (close to wavelength of 13.5 nm Si/Mo multilayer mirrors have a high reflectivity at normal incidence angles). In this work, pinching of nitrogen-filled capillary discharge is studied for the development of EUV laser, which is based on recombination pumping scheme. The goal of this study is achieving the required plasma conditions using a capillary discharge Z-pinch apparatus. In experiments with nitrogen, the capillary length was shortened from 232 mm to 90 mm and current quarter-period was changed from 60 ns to 50 ns in contrast with early experiments with Ne-like argon laser. EUV radiation from capillary discharge was registered by X-ray vacuum diode for different pressure, amplitude and duration of pre-pulse and charging voltage of the Marx generator.

  11. Simulations of Slow Capillary Discharges for BELLA

    NASA Astrophysics Data System (ADS)

    Johnson, Jeffrey; Colella, Phillip; Geddes, Cameron; Esarey, Eric; Leemans, Wim; Mittelberger, Daniel; Bulanov, Stepan; Stoltz, Peter

    2010-11-01

    Capillary plasma channels are used to extend the propagation distance of relativistically intense laser pulses for laser plasma acceleration [1], and axial density modulation has been used to stabilize injection at LBNL. Channel formation is a complex process in which a gas is ionized via a slow discharge, and subsequently stabilized by a capillary wall via heat transfer. Here we describe simulations using a multi-species, 2-temperature plasma model to study the effects of electrical and thermal conduction, species diffusion, and externally-applied magnetic fields on this process for present experiments and to plan m-scale capillaries at reduced densities for the BELLA laser. These radially-symmetric simulations, performed with the 1D cylindrical code SCYLLA from LBNL, resolve the radial behavior of the plasma within the capillary but do not accurately describe dynamics near the ends of the capillary or near gas feed slots or jets. To understand these regions, we present results of simulations using the 3-dimensional hydrodynamics code HYDRA from Lawrence Livermore National Laboratory. We discuss work in progress on a multi-dimensional plasma model that leverages results from these simulations. References: [1] W. Leemans et al., Nat. Phys. 2, 696 (2006)

  12. Passive Reactor Cooling Using Capillary Porous Wick

    SciTech Connect

    Miller, Christopher G.; Lin, Thomas F.

    2006-07-01

    Long-term reliability of actively pumped cooling systems is a concern in space-based nuclear reactors. Capillary-driven passive cooling systems are being considered as an alternative to gravity-driven systems. The high surface tension of liquid lithium makes it attractive as the coolant in a capillary-driven cooling system. A system has been conceived in which the fuel rod of a reactor is surrounded by a concentric wick through which liquid lithium flows to provide cooling under normal and emergency operating conditions. Unheated wicking experiments at three pressures using four layered screen mesh wicks of different porosities and three relatively high surface tension fluids have been conducted to gain insight into capillary phenomena for such a capillary cooling system. All fluids tested demonstrated wicking ability in each of the wick structures for all pressures, and wicking ability for each fluid increased with decreasing wick pore size. An externally heated wicking experiment with liquid lithium as the wicking fluid was also conducted. In addition to wicking experiments, a heater rod is under development to simulate the fuel rod of a space based nuclear reactor by providing a heat flux of up to 110 kW/m{sup 2}. Testing of this heater rod has shown its ability to undergo repeated cycling from below 533 K to over 1255 K without failure. This heater rod will be integrated into lithium wicking experiments to provide more realistic simulation of the proposed capillary-driven space nuclear reactor cooling system. (authors)

  13. Restructuring and aging in a capillary suspension

    E-print Network

    Erin Koos; Wolfgang Kannowade; Norbert Willenbacher

    2014-10-16

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

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

    PubMed Central

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

    2013-01-01

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

  15. Novel absorption detection techniques for capillary electrophoresis

    SciTech Connect

    Xue, Y.

    1994-07-27

    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.

  16. Capillary movement of liquid in granular beds

    SciTech Connect

    Yendler, B.; Webbon, B.

    1993-12-31

    Knowledge of capillary migration of liquids in granular beds in microgravity is essential for the development of a substrate based nutrient delivery sytem for the growth of plants in space. This problem is also interesting from the theoretical as well as the practical point of view. The purpose of this study was to model capillary water propagation through a granular bed in microgravity. In our ground experiments, water propagation is driven primarily by capillary force. Data for spherical partical sizes in the range from 0.46 to 2 mm have been obtained. It was shown that the velocity of water propagation is very sensitive to particle size. Theoretical consideration is also provided. Actual space flight experiments are planned for the future to confirm our results.

  17. Mach-like capillary-gravity wakes.

    PubMed

    Moisy, Frédéric; Rabaud, Marc

    2014-08-01

    We determine experimentally the angle ? of maximum wave amplitude in the far-field wake behind a vertical surface-piercing cylinder translated at constant velocity U for Bond numbers Bo(D)=D/?(c) ranging between 0.1 and 4.2, where D is the cylinder diameter and ?(c) the capillary length. In all cases the wake angle is found to follow a Mach-like law at large velocity, ??U(-1), but with different prefactors depending on the value of Bo(D). For small Bo(D) (large capillary effects), the wake angle approximately follows the law ??c(g,min)/U, where c(g,min) is the minimum group velocity of capillary-gravity waves. For larger Bo(D) (weak capillary effects), we recover a law ???[gD]/U similar to that found for ship wakes at large velocity [Rabaud and Moisy, Phys. Rev. Lett. 110, 214503 (2013)]. Using the general property of dispersive waves that the characteristic wavelength of the wave packet emitted by a disturbance is of order of the disturbance size, we propose a simple model that describes the transition between these two Mach-like regimes as the Bond number is varied. We show that the new capillary law ??c(g,min)/U originates from the presence of a capillary cusp angle (distinct from the usual gravity cusp angle), along which the energy radiated by the disturbance accumulates for Bond numbers of order of unity. This model, complemented by numerical simulations of the surface elevation induced by a moving Gaussian pressure disturbance, is in qualitative agreement with experimental measurements. PMID:25215822

  18. Separation of related opiate compounds using capillary electrochromatography

    E-print Network

    Separation of related opiate compounds using capillary electrochromatography Capillary electrophoretic separations have been investigated for six controlled narcotic analgesic compounds having related failed to provide a satisfac- tory separation, whereas a baseline-resolved separation was achieved in 10

  19. Use of Plastic Capillaries for Macromolecular Crystallization

    NASA Technical Reports Server (NTRS)

    Potter, Rachel R.; Hong, Young-Soo; Ciszak, Ewa M.

    2003-01-01

    Methods of crystallization of biomolecules in plastic capillaries (Nalgene 870 PFA tubing) are presented. These crystallization methods used batch, free-interface liquid- liquid diffusion alone, or a combination with vapor diffusion. Results demonstrated growth of crystals of test proteins such as thaumatin and glucose isomerase, as well as protein studied in our laboratory such dihydrolipoamide dehydrogenase. Once the solutions were loaded in capillaries, they were stored in the tubes in frozen state at cryogenic temperatures until the desired time of activation of crystallization experiments.

  20. Laser absorption waves in metallic capillaries

    NASA Astrophysics Data System (ADS)

    Anisimov, V. N.; Arutiunian, R. V.; Bol'Shov, L. A.; Kanevskii, M. F.; Kondrashov, V. V.

    1987-07-01

    The propagation of laser absorption waves in metallic capillaries was studied experimentally and numerically during pulsed exposure to CO2 laser radiation. The dependence of the plasma front propagation rate on the initial air pressure in the capillary is determined. In a broad range of parameters, the formation time of the optically opaque plasma layer is governed by the total laser pulse energy from the beginning of the exposure to the instant screening appears, and is weakly dependent on the pulse shape and gas pressure.

  1. Observation of gravity-capillary wave turbulence

    E-print Network

    Eric Falcon; Claude Laroche; Stéphan Fauve

    2007-03-07

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

  2. Control of electroosmosis in coated quartz capillaries

    NASA Technical Reports Server (NTRS)

    Herren, Blair J.; Van Alstine, James; Snyder, Robert S.; Shafer, Steven G.; Harris, J. Milton

    1987-01-01

    The effectiveness of various coatings for controlling the electroosmotic fluid flow that hinders electrophoretic processes is studied using analytical particle microelectrophoresis. The mobilities of 2-micron diameter glass and polystyrene latex spheres (exhibiting both negative and zero effective surface charge) were measured in 2-mm diameter quartz capillaries filled with NaCl solutions within the 3.5-7.8 pH range. It is found that capillary inner surface coatings using 5000 molecular weight (or higher) poly(ethylene glycol): significantly reduced electroosmosis within the selected pH range, were stable for long time periods, and appeared to be more effective than dextran, methylcellulose, or silane coatings.

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

    SciTech Connect

    Abbas Firoozabadi

    2003-12-01

    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.

  4. Spectrometer capillary vessel and method of making same

    DOEpatents

    Linehan, John C. (Richland, WA); Yonker, Clement R. (Kennewick, WA); Zemanian, Thomas S. (Richland, WA); Franz, James A. (Kennewick, WA)

    1995-01-01

    The present invention is an arrangement of a glass capillary tube for use in spectroscopy. In particular, the invention is a capillary arranged in a manner permitting a plurality or multiplicity of passes of a sample material through a spectroscopic measurement zone. In a preferred embodiment, the multi-pass capillary is insertable within a standard NMR sample tube. The present invention further includes a method of making the multi-pass capillary tube and an apparatus for spinning the tube.

  5. Spectrometer capillary vessel and method of making same

    DOEpatents

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

    1995-11-21

    The present invention is an arrangement of a glass capillary tube for use in spectroscopy. In particular, the invention is a capillary arranged in a manner permitting a plurality or multiplicity of passes of a sample material through a spectroscopic measurement zone. In a preferred embodiment, the multi-pass capillary is insertable within a standard NMR sample tube. The present invention further includes a method of making the multi-pass capillary tube and an apparatus for spinning the tube. 13 figs.

  6. The Fast and Non-capillary Fluid Filling Mechanism in the Hummingbird's Tongue

    NASA Astrophysics Data System (ADS)

    Rico-Guevara, Alejandro; Fan, Tai-Hsi; Rubega, Margaret

    2014-03-01

    Hummingbirds gather nectar by inserting their beaks inside flowers and cycling their tongues at a frequency of up to 20 Hz. It is unclear how they achieve efficiency at this high licking rate. Ever since proposed in 1833, it has been believed that hummingbird tongues are a pair of tiny straws filled with nectar by capillary rise. Our discoveries are very different from this general consensus. The tongue does not draw up floral nectar via capillary action under experimental conditions that resemble natural ones. Theoretical models based on capillary rise were mistaken and unsuitable for estimating the fluid intake rate and to support foraging theories. We filmed (up to 1265 frames/s) the fluid uptake in 20 species of hummingbirds that belong to 7 out of the 9 main hummingbird clades. We found that the fluid filling within the portions of the tongue that remain outside the nectar is about five times faster than capillary filling. We present strong evidence to rule out the capillarity model. We introduce a new fluid-structure interaction and hydrodynamic model and compare the results with field experimental data to explain how hummingbirds actually extract fluid from flowers at the lick level.

  7. Laser illumination of multiple capillaries that form a waveguide

    DOEpatents

    Dhadwal, H.S.; Quesada, M.A.; Studier, F.W.

    1998-08-04

    A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis. 35 figs.

  8. Polymeric matrices for DNA sequencing by capillary electrophoresis

    E-print Network

    Barron, Annelise E.

    materials that have been tested for DNA sequencing by capillary elec- trophoresis (CE). HypothesizedPolymeric matrices for DNA sequencing by capillary electrophoresis We review the wide range of polymeric materials that have been employed for DNA sequencing separations by capillary electrophoresis

  9. SEPARATION OF GLUTEN PROTEINS BY HIGH PERFORMANCE CAPILLARY ELECTROPHORESIS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High performance capillary electrophoresis (HPCE) is an analytical method that uses a voltage differential to accurately move solvents and solutes through a capillary. HPCE is a relative newcomer to the field of cereal chemistry, it utilizes small inner diameter capillaries as an anti-convective med...

  10. Laser illumination of multiple capillaries that form a waveguide

    DOEpatents

    Dhadwal, Harbans S. (Setauket, NY); Quesada, Mark A. (Middle Island, NY); Studier, F. William (Stony Brook, NY)

    1998-08-04

    A system and method are disclosed for efficient laser illumination of the interiors of multiple capillaries simultaneously, and collection of light emitted from them. Capillaries in a parallel array can form an optical waveguide wherein refraction at the cylindrical surfaces confines side-on illuminating light to the core of each successive capillary in the array. Methods are provided for determining conditions where capillaries will form a waveguide and for assessing and minimizing losses due to reflection. Light can be delivered to the arrayed capillaries through an integrated fiber optic transmitter or through a pair of such transmitters aligned coaxially at opposite sides of the array. Light emitted from materials within the capillaries can be carried to a detection system through optical fibers, each of which collects light from a single capillary, with little cross talk between the capillaries. The collection ends of the optical fibers can be in a parallel array with the same spacing as the capillary array, so that the collection fibers can all be aligned to the capillaries simultaneously. Applicability includes improving the efficiency of many analytical methods that use capillaries, including particularly high-throughput DNA sequencing and diagnostic methods based on capillary electrophoresis.

  11. Incorporation of polymerizable surfactants in hydroxyethyl methacrylate lenses for improving wettability and lubricity.

    PubMed

    Bengani, Lokendrakumar C; Scheiffele, Gary W; Chauhan, Anuj

    2015-05-01

    Dryness and discomfort are the main reasons for dropouts in contact lens wearers. Incorporating surfactants in lens formulations could improve wettability and lubricity, which can improve comfort. We have focused on incorporating polymerizable surfactants in hydroxyethyl methacrylate lenses to improve comfort, while minimizing the potential for surfactant release into the tears. The surfactants were added to the polymerization mixture, followed by UV curing and extraction of leachables in hot water. Wettability and lubricity were characterized by measuring the contact angle and coefficient of friction. Lenses were also characterized by measuring transmittance, loss and storage moduli and ion permeability. Incorporation of surfactants significantly reduced contact angle from 90° for p-HEMA gels to about 10° for 2.43% (w/w) surfactant loading in hydrated gel. The coefficient of friction also decreased from about 0.16 for HEMA gels to 0.05 for the gels with 2.43% surfactant loading. There was a good correlation between the contact angle and coefficient of friction suggesting that both effects can be related to the stretching of the surfactant tails near the surface into the aqueous phase. The water content was also correlated with the surfactant loading but the contact angle was more sensitive suggesting that the observed improvements in wettability and lubricity arise from the protrusion of the surfactant tails in into the liquid, and not purely from the increase in the water content. The gels were clear and certain compositions also have the capability to block UVC and UVB radiation. The results suggest that incorporation of polymerizable surfactants could be useful in improving surface properties without significantly impacting any bulk property. PMID:25596369

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

    PubMed

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

    2014-05-01

    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

  13. Photo-induced wettability of TiO{sub 2} film with Au buffer layer

    SciTech Connect

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

    2014-04-24

    The effect of thickness of Au buffer layer (15-25 nm) between TiO{sub 2} film and substrate on the wettability of TiO{sub 2} films is reported. TiO{sub 2} 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.

  14. Self-erasing and rewritable wettability patterns on ZnO thin films

    SciTech Connect

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

    2010-07-26

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

  15. Simple relations for wettability of a droplet on a low-surface-energy solid

    SciTech Connect

    Yonemoto, Yukihiro; Kunugi, Tomoaki

    2014-04-11

    A treatment of the contact angle is very difficult because it exhibits a hysteresis such as dynamic contact angle and does not necessarily take a constant value. For understanding such complicated behavior of droplet, simple but fundamental consideration is very important. In the present study, wettability of a binary mixture droplet on low surface energy solid is experimentally and theoretically investigated. A simple theoretical model is applied to the droplet behavior considering a situation before and after touching the solid surface from a view point of thermodynamic surface energy. The model can explain the relationships among the contact angle (?), surface energy of liquid (?{sub lg}) and the droplet radius (R)

  16. Macroscopic theory for capillary-pressure hysteresis.

    PubMed

    Athukorallage, Bhagya; Aulisa, Eugenio; Iyer, Ram; Zhang, Larry

    2015-03-01

    In this article, we present a theory of macroscopic contact angle hysteresis by considering the minimization of the Helmholtz free energy of a solid-liquid-gas system over a convex set, subject to a constant volume constraint. The liquid and solid surfaces in contact are assumed to adhere weakly to each other, causing the interfacial energy to be set-valued. A simple calculus of variations argument for the minimization of the Helmholtz energy leads to the Young-Laplace equation for the drop surface in contact with the gas and a variational inequality that yields contact angle hysteresis for advancing/receding flow. We also show that the Young-Laplace equation with a Dirichlet boundary condition together with the variational inequality yields a basic hysteresis operator that describes the relationship between capillary pressure and volume. We validate the theory using results from the experiment for a sessile macroscopic drop. Although the capillary effect is a complex phenomenon even for a droplet as various points along the contact line might be pinned, the capillary pressure and volume of the drop are scalar variables that encapsulate the global quasistatic energy information for the entire droplet. Studying the capillary pressure versus volume relationship greatly simplifies the understanding and modeling of the phenomenon just as scalar magnetic hysteresis graphs greatly aided the modeling of devices with magnetic materials. PMID:25646688

  17. Design criteria for SW-205 capillary system

    SciTech Connect

    Lyons, W.J.

    1989-04-01

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

  18. A novel capillary polymerase chain reaction machine

    E-print Network

    Chiou, Jeffrey Tsungshuan

    2001-01-01

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

  19. Capillary Electrophoresis for the Analysis of Biopolymers

    E-print Network

    Krylov, Sergey

    Postreplication Modification 114R Proteins and Peptides 114R Separation 114R Detection 118R Posttranslational: nucleic acids, proteins, lipids, and carbohydrates. While this review formally covers 1998 and 1999, we-scale capillary array electrophoresis instruments have been marketed by PE Biosystems (the model 3700 Genetic

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

    PubMed

    Lim, Hosub; Tripathi, Anubhav; Lee, Jinkee

    2014-08-12

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

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

    SciTech Connect

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

    2007-09-30

    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.

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

    PubMed

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

    2015-02-01

    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

  3. Absence of restricted diffusion in cutaneous capillaries.

    PubMed

    Paaske, W P

    1977-07-01

    Capillary permeability in cutaneous tissue for 57Co-cyanocobalamin (57 Co-B12) was determined by the single injection, external registration method. The capillary diffusion capacity, CDC (the permeability--surface area product, PS) was 2.3 ml/100 g-min. Capillary extraction was 0.48 at a plasma flow of 4.1 ml/100 g-min. Results were compared to 51Cr-EDTA data from a previous study with identical method and preparation. As CDC(51Cr-EDTA)/CDC(57Co-B12) was 1.61 and as D(51Cr-EDTA)/D(57Co-B12), the ratio between the free diffusion coefficients in water at 37 degrees C, was 1.79 it is concluded that restricted diffusion does not occur in cutaneous tissue for 57Co-B12 as compared to 51Cr-EDTA, i.e. 51Cr-EDTA and 57Co-B12 diffuse across the capillary membrane of cutaneous tissues at rates proportional to their respective free diffusion coefficients in water. The Pappenheimer equivalent pore radius estimate of 30 A and the Karnovsky interendothelial 40 A slit width are both defective in explaining the experimental data. The transendothelial patent channel system of fused vesicles (Simionescu, Simionescu and Palade 1975) is a possible structural equivalent for the present findings. The results support the hypothesis that capillaries of continuous type exhibit similar permeation characteristics regardless of the tissue in which they are located. PMID:411329

  4. New concept for coal wettability evaluation and modulation. Technical progress report for the project, July 1, 1995--September 30, 1995

    SciTech Connect

    Hu, W.

    1995-12-31

    This project is concerned with the new concept for coal surface wettability and floatability evaluation and modulation. the objective of the work is the fundamental surface chemistry features about the evaluation of the surface wettability and floatability of coal and pyrite, and establish a new separation strategy which could contribute to advanced coal-cleaning for premium fuel application. In this quarter, the mini-cell flotation tests are conducted to study kinetic floatability and kinetic collectability of coal and pyrite. The kinetic floatability of the five samples have been tested with methanol, butanol, and hexanol as collector.

  5. Carbonic anhydrase is abundant in fenestrated capillaries of cherry hemangioma.

    PubMed

    Eichhorn, M; Jungkunz, W; Wörl, J; Marsch, W C

    1994-01-01

    A strong correlation has been found between carbonic anhydrase (CA) activity and fenestrations in juxtaepithelial capillaries of several tissues, including psoriatic lesions of human skin. In the present study we demonstrate that the majority of the capillaries in cherry hemangiomas are fenestrated and histochemically react CA positively. Obviously the occurrence of CA in these capillaries corresponds to the fenestrations of venous capillaries, which are numerously revealed by electron microscopy. In normal undiseased skin no capillary staining for CA was observed. Therefore in a large proportion of the capillaries of cherry hemangiomas the correlation between fenestrations and CA activity also exists. We suggest that the histochemical demonstration of CA activity might serve as a sensitive and simple marker for fenestrated capillaries in skin tissue. PMID:7908484

  6. Biofilm formation on a TiO2 nanotube with controlled pore diameter and surface wettability

    NASA Astrophysics Data System (ADS)

    Anitha, V. C.; Lee, Jin-Hyung; Lee, Jintae; Narayan Banerjee, Arghya; Joo, Sang Woo; Min, Bong Ki

    2015-02-01

    Titania (TiO2) nanotube arrays (TNAs) with different pore diameters (140 - 20 nm) are fabricated via anodization using hydrofluoric acid (HF) containing ethylene glycol (EG) by changing the HF-to-EG volume ratio and the anodization voltage. To evaluate the effects of different pore diameters of TiO2 nanotubes on bacterial biofilm formation, Shewanella oneidensis (S. oneidensis) MR-1 cells and a crystal-violet biofilm assay are used. The surface roughness and wettability of the TNA surfaces as a function of pore diameter, measured via the contact angle and AFM techniques, are correlated with the controlled biofilm formation. Biofilm formation increases with the decreasing nanotube pore diameter, and a 20 nm TiO2 nanotube shows the maximum biofilm formation. The measurements revealed that 20 nm surfaces have the least hydrophilicity with the highest surface roughness of ˜17 nm and that they show almost a 90% increase in the effective surface area relative to the 140 nm TNAs, which stimulate the cells more effectively to produce the pili to attach to the surface for more biofilm formation. The results demonstrate that bacterial cell adhesion (and hence, biofilm formation) can effectively be controlled by tuning the roughness and wettability of TNAs via controlling the pore diameters of TNA surfaces. This biofilm formation as a function of the surface properties of TNAs can be a potential candidate for both medical applications and as electrodes in microbial fuel cells.

  7. Microstructure and wettability of root canal dentine and root canal filling materials after different chemical irrigation

    NASA Astrophysics Data System (ADS)

    Antonijevic, Djordje; Milovanovic, Petar; Brajkovic, Denis; Ilic, Dragan; Hahn, Michael; Amling, Michael; Rakocevic, Zlatko; Djuric, Marija; Busse, Björn

    2015-11-01

    The objective of this study was to determine the effects of various irrigation solutions on root canal dentine and gutta-percha surface properties. In addition, the effects of disinfectant chemicals on the wettability and surface morphological properties of the filling materials were evaluated. Ethylenediaminetetraacetic acid (EDTA), citric acid, and ozone were employed as irrigation solutions for dentine and gutta-percha treatment. Thereafter, the samples' microstructure, degree of mineralization, and mechanical properties were assessed by means of quantitative backscattered electron imaging (qBEI) and reference point indentation (RPI). A contact angle analyzer was used to measure adhesion on the tested materials. Here, EDTA had the most significant affect on both the mechanical properties and the adhesive behavior of dentine. Citric acid did not affect dentine wettability, whereas the indentation properties and the mineralization were reduced. Similar effects were observed when ozone was used. The dentinal tubules were significantly widened in citric acid compared to the ozone group. EDTA causes considerable micromechanical surface alteration of dentine and gutta-percha, but represents the best option in clinical cases where a high adhesiveness of the filling materials is desired.

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

    NASA Astrophysics Data System (ADS)

    Alyousef, Yousef M.

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

  9. Leaf Surface Wettability and Implications for Drop Shedding and Evaporation from Forest Canopies

    NASA Astrophysics Data System (ADS)

    Konrad, W.; Ebner, M.; Traiser, C.; Roth-Nebelsick, A.

    2012-05-01

    Wettability and retention capacity of leaf surfaces are parameters that contribute to interception of rain, fog or dew by forest canopies. Contrary to common expectation, hydrophobicity or wettability of a leaf do not dictate the stickiness of drops to leaves. Crucial for the adhesion of drops is the contact angle hysteresis, the difference between leading edge contact angle and trailing edge contact angle for a running drop. Other parameters that are dependent on the static contact angle are the maximum volume of drops that can stick to the surface and the persistence of an adhering drop with respect to evaporation. Adaption of contact angle and contact angle hysteresis allow one to pursue different strategies of drop control, for example efficient water shedding or maximum retention of adhering water. Efficient water shedding is achieved if contact angle hysteresis is low. Retention of (isolated) large drops requires a high contact angle hysteresis and a static contact angle of 65.5°, while maximum retention by optimum spacing of drops necessitates a high contact angle hysteresis and a static contact angle of 111.6°. Maximum persistence with respect to evaporation is obtained if the static contact angle amounts to 77.5°, together with a high contact angle hysteresis. It is to be expected that knowledge of these parameters can contribute to the capacity of a forest to intercept water.

  10. The Wettability of LaRC Colorless Polyimide Resins on Casting Surfaces

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

    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.

  11. Study on the Wettability and Tribological Behavior of Different Polymers as Bearing Materials for Cervical Prosthesis

    NASA Astrophysics Data System (ADS)

    Wang, Song; Song, Jian; Liao, Zhenhua; Liu, Yuhong; Zhang, Caixia; Liu, Weiqiang

    2015-06-01

    Tribological behaviors of four polymers (conventional and cross-linked UHMWPE, conventional and glass fiber-reinforced PEEK) articulated with Ti6Al4V ball were studied under both dry sliding and 25% bovine serum lubrication. The hardness, static contact angle, surface damage topography, and wear parameter of wear scar were tested. Both cross-linked process of UHMWPE and glass fiber-reinforced treatment of PEEK improved wettability while they did not increase hardness. PEEK revealed higher surface hardness and better wettability than UHMWPE. The dominant wear mechanisms for UHMWPE were plastic deformation and fatigue wear while the failure mechanisms were severe adhesive and abrasive wear for PEEK. Cross-linked process of UHMWPE could form multi-molecular arrangement and reduce stratification, also decreasing friction coefficient and wear rate in both dry sliding and lubrication conditions. However, glass fiber-reinforced treatment of PEEK only decreased its friction coefficient and wear rate in dry condition, which was closely related to the function and wear mechanism of glass fiber. Cross-linked UHMWPE revealed the lowest friction coefficient and wear rate under lubrication condition, which was attributed to the cross-linked treatment and the formation of both protein adsorption film and lubrication film. Hence, cross-linked UHMWPE may be an alternative polymer for use as artificial cervical disc bearing material when it articulated with Ti6Al4V.

  12. The optical, wettability and hardness properties of polyethylene improved by alpha particle irradiations.

    PubMed

    Zaki, M F

    2015-12-01

    In this work, the optical, chemical and morphological changes of alpha irradiated low-density polyethylene (LDPE) were investigated using UV/Vis spectroscopy, Fourier transform infrared spectrometer (FTIR) and scanning electron microscope (SEM). In addition to, the wettability and Vicker's Micro-Hardness have been studied using the contact angle measurements and Vicker's Micro-Hardness tester. The polymer samples are irradiated with different times of alpha particles. UV/Vis spectra show that the absorbance increases with increase in the irradiation time and the absorption edge shifts toward the higher wavelength. This indicates to a decrease in the optical band gap energy and an increase in number of carbon clusters. FTIR analysis reveals that the formation of CH groups and O-H has been observed and also indicated the presence of unsaturations due to vinyl end groups in the irradiated samples. Noticeable decreases in the contact angle of irradiated samples were observed. This decrease reflects the increase in the wettability and consequently the surface free energy. This behavior is due to the formation of oxidized layer on the irradiated surface polymer. Induced increasing in the Vicker's hardness in the irradiated polymers was observed, that can be attributed to crosslinking effects in the chain of the polymers. PMID:26184467

  13. Wettability modification of human tooth surface by water and UV and electron-beam radiation.

    PubMed

    Tiznado-Orozco, Gaby E; Reyes-Gasga, José; Elefterie, Florina; Beyens, Christophe; Maschke, Ulrich; Brès, Etienne F

    2015-12-01

    The wettability of the human tooth enamel and dentin was analyzed by measuring the contact angles of a drop of distilled water deposited on the surface. The samples were cut along the transverse and longitudinal directions, and their surfaces were subjected to metallographic mirror-finish polishing. Some samples were also acid etched until their microstructure became exposed. Wettability measurements of the samples were done in dry and wet conditions and after ultraviolet (UV) and electron beam (EB) irradiations. The results indicate that water by itself was able to increase the hydrophobicity of these materials. The UV irradiation momentarily reduced the contact angle values, but they recovered after a short time. EB irradiation raised the contact angle and maintained it for a long time. Both enamel and dentin surfaces showed a wide range of contact angles, from approximately 10° (hydrophilic) to 90° (hydrophobic), although the contact angle showed more variability on enamel than on dentin surfaces. Whether the sample's surface had been polished or etched did not influence the contact angle value in wet conditions. PMID:26354248

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

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

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

  15. Tuning the Wettability of Halloysite Clay Nanotubes by Surface Carbonization for Optimal Emulsion Stabilization.

    PubMed

    Owoseni, Olasehinde; Zhang, Yueheng; Su, Yang; He, Jibao; McPherson, Gary L; Bose, Arijit; John, Vijay T

    2015-12-29

    The carbonization of hydrophilic particle surfaces provides an effective route for tuning particle wettability in the preparation of particle-stabilized emulsions. The wettability of naturally occurring halloysite clay nanotubes (HNT) is successfully tuned by the selective carbonization of the negatively charged external HNT surface. The positively charge chitosan biopolymer binds to the negatively charged external HNT surface by electrostatic attraction and hydrogen bonding, yielding carbonized halloysite nanotubes (CHNT) on pyrolysis in an inert atmosphere. Relative to the native HNT, the oil emulsification ability of the CHNT at intermediate levels of carbonization is significantly enhanced due to the thermodynamically more favorable attachment of the particles at the oil-water interface. Cryogenic scanning electron microscopy (cryo-SEM) imaging reveals that networks of CHNT attach to the oil-water interface with the particles in a side-on orientation. The concepts advanced here can be extended to other inorganic solids and carbon sources for the optimal design of particle-stabilized emulsions. PMID:26633133

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

    PubMed Central

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

    2014-01-01

    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. PMID:25061758

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

    SciTech Connect

    Al-Raoush, Riyadh I.

    2009-07-31

    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.

  18. Bioanalytical profile of the L-arginine/nitric oxide pathway and its evaluation by capillary electrophoresis?

    PubMed Central

    Boudko, Dmitri Y.

    2007-01-01

    This review briefly summarizes recent progress in fundamental understanding and analytical profiling of the L-arginine/nitric oxide (NO) pathway. It focuses on key analytical references of NO actions and on the experimental acquisition of these references in vivo, with capillary electrophoresis (CE) and high-performance capillary electrophoresis (HPCE) comprising one of the most flexible and technologically promising analytical platform for comprehensive high-resolution profiling of NO-related metabolites. Second aim of this review is to express demands and bridge efforts of experimental biologists, medical professionals and chemical analysis-oriented scientists who strive to understand evolution and physiological roles of NO and to develop analytical methods for use in biology and medicine. PMID:17329176

  19. a Comprehensive Model for Capillary Pressure Difference across a Drop/bubble Flowing Through a Constricted Capillary

    NASA Astrophysics Data System (ADS)

    Liang, Mingchao; Wei, Junhong; Han, Hongmei; Fu, Chengguo; Liu, Jianjun

    2015-09-01

    The capillary pressure is one of the crucial parameters in many science and engineering applications such as composite materials, interface science, chemical engineering, oil exploration, etc. The drop/bubble formation and its mechanisms that affect the permeability of porous media have steadily attracted much attention in the past. When a drop/bubble moves from a larger capillary to a smaller one, it is often obstructed by an additional pressure difference caused by the capillary force. In this paper, a comprehensive model is derived for the capillary pressure difference when a drop/bubble flows through a constricted capillary, i.e. a geometrically constricted passage with an abrupt change in radius. The proposed model is expressed as a function of the smaller capillary radius, pore-throat ratio, contact angle, surface tension and length of the drop/bubble in the smaller capillary. The model predictions are compared with the available experimental data, and good agreement is found between them.

  20. SKELETAL MUSCLE CAPILLARY FUNCTION: CONTEMPORARY OBSERVATIONS AND NOVEL HYPOTHESES

    PubMed Central

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

    2014-01-01

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

  1. Capillary solitons on a levitated medium.

    PubMed

    Perrard, S; Deike, L; Duchêne, C; Pham, C-T

    2015-07-01

    A water cylinder deposited on a heated channel levitates on its own generated vapor film owing to the Leidenfrost effect. This experimental setup permits the study of the one-dimensional propagation of surface waves in a free-to-move liquid system. We report the observation of gravity-capillary waves under a dramatic reduction of gravity (up to a factor 30), leading to capillary waves at the centimeter scale. The generated nonlinear structures propagate without deformation and undergo mutual collisions and reflections at the boundaries of the domain. They are identified as Korteweg-de Vries solitons with negative amplitude and subsonic velocity. The typical width and amplitude-dependent velocities are in excellent agreement with theoretical predictions based on a generalized Korteweg-de Vries equation adapted to any substrate geometry. When multiple solitons are present, they interact and form a soliton turbulencelike spectrum. PMID:26274114

  2. [Functional morphology of endonasal blood capillaries].

    PubMed

    Grevers, G

    1989-01-01

    Harvey (1628) was the first to describe the blood circulatory system. 50 years later, the capillary system was discovered by Marcello Malpighi as a link between arteries and veins. Since then, the microvascular network has been examined abundantly by means of various morphological and physiological techniques. During the last decades the development of the technical equipment enabled us to receive detailed informations on the structural and ultrastructural aspects of the vasculature and--particularly--the capillary endothelium. New electron microscopic investigations on the behaviour of this special cell system. In the present study we combined our own morphological results on the endonasal microcirculatory system--using different morphological techniques--to interpret these anatomical finding under functional aspects. PMID:2644502

  3. Capillary flow through heat-pipe wicks

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.

    1975-01-01

    Theoretical expressions are obtained for the capillary-pressure limit and permeability of a fibrous wick in terms of the porosity and fiber diameter. Hysteresis in capillary pressure is included through the introduction of an empirical hysteresis constant. A partial-saturation model based on the statistical distribution of local porosity requires an additional empirical constant, the standard deviation. The theory is compared to results of a beta-ray absorption experiment that measured the liquid content of a partially saturated wick and to results of permeability measurements on partially and fully saturated wicks. A simple wick-weighing experiment is described that yields values for the empirical hysteresis constant and the standard deviation. Theoretical results are used to design an optimum wick.

  4. Capillary wrinkling of floating thin polymer films.

    PubMed

    Huang, Jiangshui; Juszkiewicz, Megan; de Jeu, Wim H; Cerda, Enrique; Emrick, Todd; Menon, Narayanan; Russell, Thomas P

    2007-08-01

    A freely floating polymer film, tens of nanometers in thickness, wrinkles under the capillary force exerted by a drop of water placed on its surface. The wrinkling pattern is characterized by the number and length of the wrinkles. The dependence of the number of wrinkles on the elastic properties of the film and on the capillary force exerted by the drop confirms recent theoretical predictions on the selection of a pattern with a well-defined length scale in the wrinkling instability. We combined scaling relations that were developed for the length of the wrinkles with those for the number of wrinkles to construct a metrology for measuring the elasticity and thickness of ultrathin films that relies on no more than a dish of fluid and a low-magnification microscope. We validated this method on polymer films modified by plasticizer. The relaxation of the wrinkles affords a simple method to study the viscoelastic response of ultrathin films. PMID:17673658

  5. High-performance capillary electrophoresis of histones

    SciTech Connect

    Gurley, L.R.; London, J.E.; Valdez, J.G.

    1991-01-01

    A high performance capillary electrophoresis (HPCE) system has been developed for the fractionation of histones. This system involves electroinjection of the sample and electrophoresis in a 0.1M phosphate buffer at pH 2.5 in a 50 {mu}m {times} 35 cm coated capillary. Electrophoresis was accomplished in 9 minutes separating a whole histone preparation into its components in the following order of decreasing mobility; (MHP) H3, H1 (major variant), H1 (minor variant), (LHP) H3, (MHP) H2A (major variant), (LHP) H2A, H4, H2B, (MHP) H2A (minor variant) where MHP is the more hydrophobic component and LHP is the less hydrophobic component. This order of separation is very different from that found in acid-urea polyacrylamide gel electrophoresis and in reversed-phase HPLC and, thus, brings the histone biochemist a new dimension for the qualitative analysis of histone samples. 27 refs., 8 figs.

  6. Formation of viscoplastic drops by capillary breakup

    NASA Astrophysics Data System (ADS)

    German, G.; Bertola, V.

    2010-03-01

    The process of growth and detachment of drops from a capillary nozzle is studied experimentally by high-speed imaging. Newtonian drops are compared to shear-thinning and viscoplastic drops. Both Newtonian and shear-thinning fluid drops grow on the end of the capillary until a maximum supportable tensile stress is reached in the drop neck, after which they become unstable and detach. The critical stress is not influenced by variations in viscosity or in the degree of shear thinning. Viscoplastic fluids show a different behavior: at low values of the yield stress, the critical stability behavior is similar to that of Newtonian and shear-thinning drops. Above a threshold value, characterized in terms of the drop size, surface tension and tensile yield-stress magnitude, yield-stress forces are larger than surface forces, and the maximum tensile stress achievable in the drop neck at the point of critical stability is governed by the von Mises criterion.

  7. Capillary breakup of discontinuously shear thickening suspensions

    NASA Astrophysics Data System (ADS)

    Zimoch, Pawel; McKinley, Gareth; Hosoi, Anette

    2011-11-01

    Extensional rheology of discontinuously shear thickening suspensions is not well understood, in part due to unresolved experimental challenges. Such suspensions tend to sag, drain or fracture when tested using traditional tools such as filament-stretching or capillary breakup extensional rheometers. We present an alternative method of conducting capillary breakup experiments with thickening suspensions by placing them between two layers of immiscible oil. In experiments conducted with silica and cornstarch particles we observe the formation of bead-on-a-string morphologies with multiple satellite and sub-satellite bead generations, similar to the morphologies observed in breakup of viscoelastic fluids. Using a one dimensional numerical model, we show that formation of beads is a consequence of the discontinuous nature of thickening in the suspensions. Finally, we delineate the parameter regimes where formation of beads occurs, and where it is suppressed.

  8. Capillary solitons on a levitated medium

    NASA Astrophysics Data System (ADS)

    Perrard, S.; Deike, L.; Duchêne, C.; Pham, C.-T.

    2015-07-01

    A water cylinder deposited on a heated channel levitates on its own generated vapor film owing to the Leidenfrost effect. This experimental setup permits the study of the one-dimensional propagation of surface waves in a free-to-move liquid system. We report the observation of gravity-capillary waves under a dramatic reduction of gravity (up to a factor 30), leading to capillary waves at the centimeter scale. The generated nonlinear structures propagate without deformation and undergo mutual collisions and reflections at the boundaries of the domain. They are identified as Korteweg-de Vries solitons with negative amplitude and subsonic velocity. The typical width and amplitude-dependent velocities are in excellent agreement with theoretical predictions based on a generalized Korteweg-de Vries equation adapted to any substrate geometry. When multiple solitons are present, they interact and form a soliton turbulencelike spectrum.

  9. In situ synthesis of homochiral metal-organic framework in capillary column for capillary electrochromatography enantioseparation.

    PubMed

    Pan, Congjie; Wang, Weifeng; Zhang, Huige; Xu, Laifang; Chen, Xingguo

    2015-04-01

    Homochiral metal-organic frameworks (MOFs) are promising as porous stationary phase for open-tubular capillary electrochromatography (OT-CEC) enantioseparation owing to their fine-tuned pore sizes and large surface areas. In this work, the homochiral MOF AlaZnCl was successfully coated on the inner wall of fused silica capillary by an in situ, layer-by-layer self-assembly approach at room temperature. The results of scanning electron microscopy (SEM), X-ray diffraction (XRD), streaming potential (SP) and Fourier-transform infrared spectroscopy (FT-IR) indicated that the homochiral MOF AlaZnCl was successfully coated on the capillary inner wall. To evaluate the performance of the homochiral MOF AlaZnCl coated capillary column, the enantioseparation was carried out by using six amine drugs and monoamine neurotransmitters as model analytes and excellent enantioseparation efficiency was achieved. Run-to-run, day-to-day, and column-to-column relative standard deviations (RSDs) were all less than 5%. Moreover, the separation efficiency of the homochiral MOF AlaZnCl coated capillary column did not decrease obviously over 100 runs. PMID:25725957

  10. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D`Silva, A.

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conductors is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer. 1 fig.

  11. Capillary zone electrophoresis-mass spectrometer interface

    DOEpatents

    D'Silva, Arthur (Ames, IA)

    1996-08-06

    A device for providing equal electrical potential between two loci unconnected by solid or liquid electrical conducts is provided. The device comprises a first electrical conducting terminal, a second electrical conducting terminal connected to the first terminal by a rigid dielectric structure, and an electrically conducting gas contacting the first and second terminals. This device is particularly suitable for application in the electrospray ionization interface between a capillary zone electrophoresis apparatus and a mass spectrometer.

  12. Capillary-Effect Root-Environment System

    NASA Technical Reports Server (NTRS)

    Wright, Bruce D.

    1991-01-01

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

  13. Surfactant effects on the water-stable aggregation of wettable soils from the continental U.S

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surfactants may affect soil structure differently depending upon the soil or the quality of rainfall or irrigation water. This study examined whether the water-stable aggregation of 11 wettable soils was affected by surfactants and the water in which the soils were sieved. The study also examined wh...

  14. Modeling of the non-isothermal liquid droplet impact on a heated solid substrate with heterogeneous wettability

    E-print Network

    Ganesan, Sashikumaar

    and jet impingement cooling. Most of the industrial applications involve droplets or spray impact on solid Keywords: Droplet impingement Heterogeneous wettability Heat transfer Marangoni convection Finite elements ALE approach a b s t r a c t A comprehensive numerical investigation on the impingement and spreading

  15. Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic glasses

    E-print Network

    Zheng, Yufeng

    , People's Republic of China 4 School of Materials Science and Engineering, Georgia Institute of Technology Institute of Physics. doi:10.1063/1.3429591 Corrosion of metallic materials in general depends on severalCorrelation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic

  16. Light-responsive nanoparticles with wettability changing from hydrophobicity to hydrophilicity and their application towards highly hydrophilic fluorocarbon coatings

    NASA Astrophysics Data System (ADS)

    Lin, Baozhong; Zhou, Shuxue

    2015-12-01

    Novel functional silica nanoparticles (SiO2-NBS-F) with irreversible light-responsive wettability were prepared by grafting of a light-responsive silane coupling agent (NBS) and further bonding with hydrophobic segments via a click reaction. The NBS was synthesized using an o-nitrobenzyl alcohol derivative of the photolabile protecting group. The SiO2-NBS-F nanoparticles exhibited considerable change of wettability from near-superhydrophobicity to near-superhydrophilicity after UV irradiation. The changing mechanism of wettability was confirmed by UV-Vis absorption spectra and X-ray photoelectron spectra. The SiO2-NBS-F nanoparticles were incorporated into fluorocarbon FEVE coatings by simple mixing. The nanoparticles occurred at the surface of the dried coatings even though their content was as low as 5 wt%, being due to their low surface free energy. The wettability of the SiO2-NBS-F filled FEVE coatings could transform from hydrophobicity (WCA 106.4°) to hydrophilicity (WCA 33.3°) after UV irradiation. It demonstrates that SiO2-NBS-F nanoparticles are useful to acquire highly hydrophilic surface for organic coatings.

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

    E-print Network

    Patzek, Tadeusz W.

    WATER RESOURCES RESEARCH, VOL. , NO. , PAGES 1­10, The Impact of Wettability Alteration on Two (NAPLs) and gases that co-exist with water in soils and rocks, is of fundamental interest to subsurface water management. Any prediction of temporal and spatial distributions of these fluids is sensitive

  18. Slip behavior in liquid films on surfaces of patterned wettability: Comparison between continuum and molecular dynamics simulations

    E-print Network

    Troian, Sandra M.

    by proportional substi- tution of liquid-solid contact area with liquid-gas contact area or equivalently, subst influenced by boundary effects 1 . Liquid affinity to nearby solid boundaries can be reduced through chemicalSlip behavior in liquid films on surfaces of patterned wettability: Comparison between continuum

  19. Measurement of Capillary Radius and Contact Angle within Porous Media.

    PubMed

    Ravi, Saitej; Dharmarajan, Ramanathan; Moghaddam, Saeed

    2015-12-01

    The pore radius (i.e., capillary radius) and contact angle determine the capillary pressure generated in a porous medium. The most common method to determine these two parameters is through measurement of the capillary pressure generated by a reference liquid (i.e., a liquid with near-zero contact angle) and a test liquid. The rate of rise technique, commonly used to determine the capillary pressure, results in significant uncertainties. In this study, we utilize a recently developed technique for independently measuring the capillary pressure and permeability to determine the equivalent minimum capillary radii and contact angle of water within micropillar wick structures. In this method, the experimentally measured dryout threshold of a wick structure at different wicking lengths is fit to Darcy's law to extract the maximum capillary pressure generated by the test liquid. The equivalent minimum capillary radii of different wick geometries are determined by measuring the maximum capillary pressures generated using n-hexane as the working fluid. It is found that the equivalent minimum capillary radius is dependent on the diameter of pillars and the spacing between pillars. The equivalent capillary radii of micropillar wicks determined using the new method are found to be up to 7 times greater than the current geometry-based first-order estimates. The contact angle subtended by water at the walls of the micropillars is determined by measuring the capillary pressure generated by water within the arrays and the measured capillary radii for the different geometries. This mean contact angle of water is determined to be 54.7°. PMID:26538412

  20. Microfab-less Microfluidic Capillary Electrophoresis Devices

    PubMed Central

    Segato, Thiago P.; Bhakta, Samir A.; Gordon, Matthew; Carrilho, Emanuel; Willis, Peter A.; Jiao, Hong; Garcia, Carlos D.

    2013-01-01

    Compared to conventional bench-top instruments, microfluidic devices possess advantageous characteristics including great portability potential, reduced analysis time (minutes), and relatively inexpensive production, putting them on the forefront of modern analytical chemistry. Fabrication of these devices, however, often involves polymeric materials with less-than-ideal surface properties, specific instrumentation, and cumbersome fabrication procedures. In order to overcome such drawbacks, a new hybrid platform is proposed. The platform is centered on the use of 5 interconnecting microfluidic components that serve as the injector or reservoirs. These plastic units are interconnected using standard capillary tubing, enabling in-channel detection by a wide variety of standard techniques, including capacitively-coupled contactless conductivity detection (C4D). Due to the minimum impact on the separation efficiency, the plastic microfluidic components used for the experiments discussed herein were fabricated using an inexpensive engraving tool and standard Plexiglas. The presented approach (named 52-platform) offers a previously unseen versatility: enabling the assembly of the platform within minutes using capillary tubing that differs in length, diameter, or material. The advantages of the proposed design are demonstrated by performing the analysis of inorganic cations by capillary electrophoresis on soil samples from the Atacama Desert. PMID:23585815

  1. On applications and limitations of one-dimensional capillarity formulations for media with heterogeneous wettability

    E-print Network

    Tafreshi, Hooman Vahedi

    On applications and limitations of one-dimensional capillarity formulations for media that are often used in characterizing the capillarity of a multi-component system (e.g., predicting capillary capillarity of the system. VC 2013 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4811167] Capillarity

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

    SciTech Connect

    Abhijit Dandekar; Shirish Patil; Santanu Khataniar

    2008-12-31

    Numerous early reports on experimental works relating to the role of wettability in various aspects of oil recovery have been published. Early examples of laboratory waterfloods show oil recovery increasing with increasing water-wetness. This result is consistent with the intuitive notion that strong wetting preference of the rock for water and associated strong capillary-imbibition forces gives the most efficient oil displacement. This report examines the effect of wettability on waterflooding and gasflooding processes respectively. Waterflood oil recoveries were examined for the dual cases of uniform and non-uniform wetting conditions. Based on the results of the literature review on effect of wettability and oil recovery, coreflooding experiments were designed to examine the effect of changing water chemistry (salinity) on residual oil saturation. Numerous corefloods were conducted on reservoir rock material from representative formations on the Alaska North Slope (ANS). The corefloods consisted of injecting water (reservoir water and ultra low-salinity ANS lake water) of different salinities in secondary as well as tertiary mode. Additionally, complete reservoir condition corefloods were also conducted using live oil. In all the tests, wettability indices, residual oil saturation, and oil recovery were measured. All results consistently lead to one conclusion; that is, a decrease in injection water salinity causes a reduction in residual oil saturation and a slight increase in water-wetness, both of which are comparable with literature observations. These observations have an intuitive appeal in that water easily imbibes into the core and displaces oil. Therefore, low-salinity waterfloods have the potential for improved oil recovery in the secondary recovery process, and ultra low-salinity ANS lake water is an attractive source of injection water or a source for diluting the high-salinity reservoir water. As part of the within-scope expansion of this project, cyclic water injection tests using high as well as low salinity were also conducted on several representative ANS core samples. These results indicate that less pore volume of water is required to recover the same amount of oil as compared with continuous water injection. Additionally, in cyclic water injection, oil is produced even during the idle time of water injection. It is understood that the injected brine front spreads/smears through the pores and displaces oil out uniformly rather than viscous fingering. The overall benefits of this project include increased oil production from existing Alaskan reservoirs. This conclusion is based on the performed experiments and results obtained on low-salinity water injection (including ANS lake water), vis-a-vis slightly altering the wetting conditions. Similarly, encouraging cyclic water-injection test results indicate that this method can help achieve residual oil saturation earlier than continuous water injection. If proved in field, this would be of great use, as more oil can be recovered through cyclic water injection for the same amount of water injected.

  3. The impact of additives found in industrial formulations of TCE on the wettability of sandstone

    NASA Astrophysics Data System (ADS)

    Harrold, Gavin; Lerner, David N.; Leharne, Stephen A.

    2005-11-01

    The wettability of aquifer rocks is a key physical parameter which exerts an important control on the transport, residual trapping, distribution and eventual fate of chlorinated hydrocarbon solvents (CHSs) released into the subsurface. Typically chlorinated solvents are assumed to be non-wetting in water saturated rocks and unconsolidated sediments. However industrially formulated solvent products are often combined with basic additives such as alkylamines to improve their performance; and the mineral surfaces of aquifer rocks and sediments usually possess a range of acid and hydrogen-bonding adsorption sites. The presence of these sites provides a mechanism whereby the basic additives in CHSs can be adsorbed at the solvent phase/solid phase interface. Given the amphiphilic molecular structure of these additives, this may result in changes in the wetting conditions of the solid phase. The aim of this study was therefore to test this conjecture for two classes of additives (alkylamines and quaternary ammonium salts) that are often encountered in industrial solvent formulations. Wettability assessments were made on sandstone cores by means of measurements of spontaneous and forced water drainage and spontaneous and forced water imbibition and through contact angle measurements on a smooth quartz surface. No solvent/additive combination produced solvent wetting conditions, though dodecylamine and octadecylamine significantly reduced the water wetting preference of sandstone which frequently resulted in neutral wetting conditions. The large volume of spontaneous water drainage observed in wettability experiments involving cetyltrimethylammonium bromide and octadecyltrimethylammonium bromide, suggested that the sandstone cores in these tests remained strongly water wetting. However equilibrium static contact angles of around 60° were measured on quartz suggesting that the sandstone surfaces should be close to neutral wetting conditions. This paradox was finally resolved by noting that contact between the solvent mixture and water in the sandstone core resulted in a final solvent phase which had an extremely low interfacial tension. It is therefore suspected that the observed spontaneous drainage of solvent from the core was driven by gravitational and buoyancy forces rather than strong water wetting conditions. Finally it was noted that the mobilisation of iron oxide coatings from the sandstone surface had a considerable influence in reducing the interfacial tension and in the formation and stabilisation of TCE/water emulsions.

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

    PubMed Central

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

    2013-01-01

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

  5. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOEpatents

    Yeung, Edward S. (Ames, IA); Kuhr, Werner G. (Riverside, CA)

    1996-02-20

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  6. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOEpatents

    Yeung, Edwards (Ames, IA); Kuhr, Werner G. (Riverside, CA)

    1991-04-09

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  7. An axial approach to detection in capillary electrophoresis

    SciTech Connect

    Taylor, J.A.

    1993-05-01

    Our approach involves on-axis illumination of the compounds inside the capillary detection region and is applied to absorbance and fluorescence detection. Absorbance measurements were made by focussing an incident laser beam into one capillary end; by using signals collected over the entire length of analyte band, this enhances the analytical path length of conventional absorbance detection 60x. This instrument offers a 15x improvement in detection limits. Three fluorescence detection experiments are discussed, all of which involve insertion of an optical fiber into capillary. The first uses a high refractive index liquid phase to obtain total internal reflectance along capillary axis, this reducing light scatter. The second uses a charge-coupled device camera for simultaneous imaging of a capillary array (this may be useful in genome sequencing, etc.). The third is a study of fluid motion inside the capillary under pressure-driven and electroosmotic flow. The thesis is divided into four parts. Figs, tabs.

  8. Separation of DNA restriction fragments using capillary electrophoresis

    SciTech Connect

    Chan, K.C.; Whang, Chenwen; Yeung, E.S. )

    1993-01-01

    Gel-filled and non-gel' capillary electrophoresis (CE) have been applied to the separation of various DNA restriction fragments. 30% HydroLink gel, polymerized inside a 75[mu]m i.d. fused-silica capillary, was used in the gel-filled CE. Primary results show that the HL capillary gel was simple to cast, and its stability was reasonably good under the running conditions. In the non-gel CE experiment, a buffer containing the sieving additive hydroxypropylmethyl cellulose was used to affect the size-dependent separation. The use of GC capillaries eliminates the inconvenience of separately coating the capillary walls for efficient non-gel separation. Finally, the authors demonstrate that it is feasible to detect native DNA fragments using indirect fluorometry in non-gel capillary electrophoresis.

  9. Capillary electrophoretic methods applied to the investigation of peptide complexes.

    PubMed

    Št?pánová, Sille; Kaši?ka, Václav

    2015-08-01

    This article gives an overview of the applications of capillary electrophoretic methods to investigate the non-covalent interactions of peptides (peptide complexes) with variable middle- and high-molecular-mass receptors (ligands) as well as with small ions and molecules in the period 2007-2014. Different modes of capillary electrophoretic methods, such as mobility shift (vacancy) affinity capillary electrophoresis, multiple injection affinity capillary electrophoresis, partial filling affinity capillary electrophoresis, Hummel-Dryer method, vacancy peak method and (continuous) frontal analysis capillary electrophoresis, are briefly described and their applicability to determination of binding constants of peptide complexes is discussed. In addition, the detailed experimental conditions of individual applications and the values of binding constants of the particular peptide complexes are presented. PMID:25982955

  10. Capillary pressure-saturation relations for supercritical CO2 and brine in limestone/dolomite sands: implications for geologic carbon sequestration in carbonate reservoirs.

    PubMed

    Wang, Shibo; Tokunaga, Tetsu K

    2015-06-16

    In geologic carbon sequestration, capillary pressure (Pc)-saturation (Sw) relations are needed to predict reservoir processes. Capillarity and its hysteresis have been extensively studied in oil-water and gas-water systems, but few measurements have been reported for supercritical (sc) CO2-water. Here, Pc-Sw relations of scCO2 displacing brine (drainage), and brine rewetting (imbibition) were studied to understand CO2 transport and trapping behavior under reservoir conditions. Hysteretic drainage and imbibition Pc-Sw curves were measured in limestone sands at 45 °C under elevated pressures (8.5 and 12.0 MPa) for scCO2-brine, and in limestone and dolomite sands at 23 °C (0.1 MPa) for air-brine using a new computer programmed porous plate apparatus. scCO2-brine drainage and imbibition curves shifted to lower Pc relative to predictions based on interfacial tension, and therefore deviated from capillary scaling predictions for hydrophilic interactions. Fitting universal scaled drainage and imbibition curves show that wettability alteration resulted from scCO2 exposure over the course of months-long experiments. Residual trapping of the nonwetting phases was determined at Pc = 0 during imbibition. Amounts of trapped scCO2 were significantly larger than for those for air, and increased with pressure (depth), initial scCO2 saturation, and time. These results have important implications for scCO2 distribution, trapping, and leakage potential. PMID:25945400

  11. Choosing Actions

    PubMed Central

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

    2013-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  13. Geometrically tuned wettability of dynamic micromechanical sensors for an improved in-liquid operation

    NASA Astrophysics Data System (ADS)

    Peiker, P.; Oesterschulze, E.

    2015-09-01

    Partial wetting is a vital tool to improve the quality factor of dynamic micromechanical sensors operated in liquids owing to the reduced viscous damping. This technique employs meniscus formation which so far could only be stabilized for a hydrophobic sensory surface excluding biosensing applications. Here, we report on the geometrically tuned wettability of particular hybrid bridge resonators (HBR) with an integrated overhang structure. This allows low-loss operation irrespective of the sensory surface material. The impact of the overhang structure on wetting is explained in a simplified model. Experimental evidence is adduced operating the HBR coated with hydrophilic thin films in water. With an in-liquid quality factor Q of 91 and a small mass m ? 5 ng of the HBR, the m/Q-ratio, which is proportional to the limit of detection for mass sensing, was significantly improved in comparison to immersed resonators presented so far.

  14. Control of surface wettability of hydroxyapatite thin films by way of crystal imperfections

    NASA Astrophysics Data System (ADS)

    Akazawa, Housei; Ueno, Yuko

    2015-10-01

    The wettability of hydroxyapatite (HAp) films can be controlled by process conditions and substrates. C-plane-terminated HAp films on Si(100) substrate were hydrophobic. Only when sputter deposition with Ar was carried out with H2O vapor, followed by solid-phase crystallization at 500-700 °C, did highly hydrophilic films with water contact angles between 10 and 20° form. The hydrophilic property was characterized by H2O bending mode signals at 1595 cm-1 in infrared spectroscopy. Preferentially c- or (310)-plane-oriented epitaxial HAp films on sapphire c-planes were hydrophobic, whereas randomly oriented polycrystalline HAp films on sapphire a-planes were moderately hydrophilic.

  15. Importance of excipient wettability on tablet characteristics prepared by moisture activated dry granulation (MADG).

    PubMed

    Takasaki, Hiroshi; Yonemochi, Etsuo; Messerschmid, Roman; Ito, Masanori; Wada, Koichi; Terada, Katsuhide

    2013-11-01

    For moisture activated dry granulation (MADG), microcrystalline cellulose (MCC) or silicon dioxide is recommended for the moisture absorption stage. The aim of this study was to assess the suitability of alternative excipients as moisture absorbents with regard to the disintegration mechanism of resulting lactose based placebo formulations. Beside high and low moisture MCC grades, the additions of magnesium aluminometasilicate (MAMS), pregelatinized starch (S1500), crospovidone (Kollidon CL) and carmellose calcium (ECG 505) were evaluated. High shear granulation (HSG) was conducted as a reference process. The overall disintegration time of all tablets produced by MADG was significantly faster whereas hardness yield and mass-variability were equal or superior compared to the HSG process. Powder wettability of the different moisture absorbents was identified to be a key driver for rapid disintegration, whereas tablet porosity had only a minor influence on the target hardness of the tablets. PMID:23994013

  16. Sessile droplet freezing and ice adhesion on aluminum with different surface wettability and surface temperature

    NASA Astrophysics Data System (ADS)

    Ou, JunFei; Shi, QingWen; Wang, ZhiLe; Wang, FaJun; Xue, MingShan; Li, Wen; Yan, GuiLong

    2015-07-01

    This paper focused on the sessile droplet freezing and ice adhesion on aluminum with different wettability (hydrophilic, common hydrophobic, and superhydrophobic surfaces, coded as HIS, CHS, SHS, respectively) over a surface temperature range of -9°C to -19°C. It was found that SHS could retard the sessile droplet freezing and lower the ice adhesion probably due to the interfacial air pockets (IAPs) on water/SHS interface. However, as surface temperature decreasing, some IAPs were squeezed out and such freezing retarding and adhesion lowering effect for SHS was reduced greatly. For a surface temperature of -19°C, ice adhesion on SHS was even greater than that on CHS. To discover the reason for the squeezing out of IAPs, forces applied to the suspended water on IAPs were analyzed and it was found that the stability of IAPs was associated with surface micro-structures and surface temperature. These findings might be helpful to designing of SHS with good anti-icing properties.

  17. Controllable Synthesis and Surface Wettability of Flower-Shaped Silver Nanocube-Organosilica Hybrid Colloidal Nanoparticles.

    PubMed

    Sun, Yangyi; Chen, Min; Zhou, Shuxue; Hu, Jing; Wu, Limin

    2015-12-22

    Synthesis of hybrid colloidal particles with complex and hierarchical structures is attracting much interest theoretically and technically in recent years, but still remains a tremendous challenge. Here, we present a mild and controllable wet-chemical method for the synthesis of silver nanocube (Ag NC)-organosilica hybrid particles with finely tuned numbers (with one, two, three, four, five, or six) and sizes of organosilica petals, by simply controlling the affinity with Ag NC/nature, amount, and prehydrolysis process of alkoxysilanes. The morphologies of hybrid colloidal particles have an obvious influence on the surface wettability of the hybrid particle-based films. More and larger organosilica petals can increase the surface hydrophobicity of the hybrid particle-based films. PMID:26564332

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  1. Splashing Threshold of Oblique Droplet Impacts on Surfaces of Various Wettability.

    PubMed

    Aboud, Damon G K; Kietzig, Anne-Marie

    2015-09-15

    Oblique drop impacts were performed at high speeds (up to 27 m/s, We > 9000) with millimetric water droplets, and a linear model was applied to define the oblique splashing threshold. Six different sample surfaces were tested: two substrate materials of different inherent surface wettability (PTFE and aluminum), each prepared with three different surface finishes (smooth, rough, and textured to support superhydrophobicity). Our choice of surfaces has allowed us to make several novel comparisons. Considering the inherent surface wettability, we discovered that PTFE, as the more hydrophobic surface, exhibits lower splashing thresholds than the hydrophilic surface of aluminum of comparable roughness. Furthermore, comparing oblique impacts on smooth and textured surfaces, we found that asymmetrical spreading and splashing behaviors occurred under a wide range of experimental conditions on our smooth surfaces; however, impacts occurring on textured surfaces were much more symmetrical, and one-sided splashing occurred only under very specific conditions. We attribute this difference to the air-trapping nature of textured superhydrophobic surfaces, which lowers the drag between the spreading lamella and the surface. The reduced drag affects oblique drop impacts by diminishing the effect of the tangential component of the impact velocity, causing the impact behavior to be governed almost exclusively by the normal velocity. Finally, by comparing oblique impacts on superhydrophobic surfaces at different impact angles, we discovered that although the pinning transition between rebounding and partial rebounding is governed primarily by the normal impact velocity, there is also a weak dependence on the tangential velocity. As a result, pinning is inhibited in oblique impacts. This led to the observation of a new behavior in highly oblique impacts on our superhydrophobic surfaces, which we named the stretched rebound, where the droplet is extended into an elongated pancake shape and rebounds while still outstretched, without exhibiting a recession phase. PMID:26318736

  2. Wettability and osteoblast cell response modulation through UV laser processing of nylon 6,6

    NASA Astrophysics Data System (ADS)

    Waugh, D. G.; Lawrence, J.

    2011-08-01

    With an ageing population the demand for cheap, efficient implants is ever increasing. Laser surface treatment offers a unique means of varying biomimetic properties to determine generic parameters to predict cell responses. This paper details how a KrF excimer laser can be employed for both laser-induced patterning and whole area irradiative processing to modulate the wettability characteristics and osteoblast cell response following 24 h and 4 day incubation. Through white light interferometry (WLI) it was found that the surface roughness had considerably increased by up to 1.5 ?m for the laser-induced patterned samples and remained somewhat constant at around 0.1 ?m for the whole area irradiative processed samples. A sessile drop device determined that the wettability characteristics differed between the surface treatments. For the patterned samples the contact angle, ?, increased by up to 25° which can be attributed to a mixed-state wetting regime. For the whole area irradiative processed samples ? decreased owed to an increase in polar component, ?P. For all samples ? was a decreasing function of the surface energy. The laser whole area irradiative processed samples gave rise to a distinct correlative trend between the cell response, ? and ?P. However, no strong relationship was determined for the laser-induced patterned samples due to the mixed-state wetting regime. As a result, owed to the relationships and evidence of cell differentiation one can deduce that laser whole area irradiative processing is an attractive technology for employment within regenerative medicine to meet the demands of an ageing population.

  3. Capillary-Condenser-Pumped Heat-Transfer Loop

    NASA Technical Reports Server (NTRS)

    Silverstein, Calvin C.

    1989-01-01

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

  4. General equation for the design of capillary tubes

    SciTech Connect

    Yilmaz, T.; Uenal, S.

    1996-03-01

    Capillary tubes are used widely in small refrigeration systems. It is necessary to design the capillary tube, but there does not exist any analytical equation which allows the determination of capillary tube length or mass flow rate for all refrigerants. In this work, an analytical equation is derived which allows them to design the capillary tubes. The comparison with existing methods and experimentally obtained values using the refrigerants R12, R22, R113, R114, R134a, and R600a has turned out to be satisfactory.

  5. Multiple beam interference model for measuring parameters of a capillary.

    PubMed

    Xu, Qiwei; Tian, Wenjing; You, Zhihong; Xiao, Jinghua

    2015-08-01

    A multiple beam interference model based on the ray tracing method and interference theory is built to analyze the interference patterns of a capillary tube filled with a liquid. The relations between the angular widths of the interference fringes and the parameters of both the capillary and liquid are derived. Based on these relations, an approach is proposed to simultaneously determine four parameters of the capillary, i.e., the inner and outer radii of the capillary, the refractive indices of the liquid, and the wall material. PMID:26368114

  6. Fluorescent Labeling Reagents Optimized for Capillary Electrophoretic Separations 

    E-print Network

    Estrada, Roy Tonacao, III

    2012-02-14

    Fluorescent labeling can improve the detection sensitivity in capillary electrophoretic (CE) separations down to attomolar concentrations. However, most fluorescent labels are not compatible with CE because their fluorescence ...

  7. Cell trapping in a blood capillary phantom using laser tweezers

    NASA Astrophysics Data System (ADS)

    Klykov, Sergei S.; Fedosov, Ivan V.; Tuchin, Valery V.

    2015-03-01

    As a phantom of native blood capillary the plastic capillary tube and as a model of red blood cells the yeast cells are considered. Plastic capillary has circular a cross-section with diameter ranging between 20 and 40 ?. For velocity estimation of polystyrene beads which had a role of tracers in water the particle image velocimetry method is realized using NI Labview Vision standard functions of image processing. It is shown that in spite of the presence of uncompensated spherical aberration emerging from refraction incident beam in curved plastic capillary walls yeast cells can be confined in stable 3D trap.

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

    NASA Technical Reports Server (NTRS)

    Lekan, Jack F.; Allen, Jeffrey S.

    1998-01-01

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

  9. Time-dependent collisional-radiative model for capillary discharge plasmas

    NASA Technical Reports Server (NTRS)

    Pockl, M.; Hebenstreit, M.; Neger, T.; Aumayr, F.

    1994-01-01

    A time-dependent, zero-dimensional collisional-radiative model has been developed to study capillary discharge plasmas in view of possibilities for obtaining population inversion leading to laser action in the extreme ultraviolet and soft x-ray spectral region, by amplifying the Balmer-alpha (H-alpha) line of different hydrogenlike ions with nuclear charges from Z = 3 to Z = 6. The model is described in detail, and results for the case of a carbon plasma are presented. Limitations of the model are discussed and comparison is made between our calculations and recent experimental results.

  10. Immiscible displacement of oil by water in consolidated porous media due to capillary imbibition under ultrasonic waves.

    PubMed

    Hamida, Tarek; Babadagli, Tayfun

    2007-09-01

    Numerous studies done in the last four decades have demonstrated that acoustic stimulation may enhance recovery in oil reservoirs. This technology is not only technically feasible, but also serves as an economical, environmentally friendly alternative to currently accepted enhanced oil recovery (EOR) method. It requires low capital expenditure, and yields almost immediate improvement without any additional EOR agents. Despite a vast body of empirical and theoretical support, this method lacks sufficient understanding to make meaningful and consistent engineering predictions. This is in part due to the complex nature of the physical processes involved, as well as due to a shortage of fundamental/experimental research. Much of what the authors believe is happening within acoustically stimulated porous media is speculative and theoretical. This paper focuses on the effects of ultrasound on the interfacial forces between immiscible fluids. Capillary (spontaneous) imbibition of an aqueous phase into oil (or air)-saturated Berea sandstone and Indiana limestone samples experiments were conducted. Solutions of water, brine (15,000 and 150,000 ppm NaCl), anionic surfactant (sodium dodecyl diphenyloxide disulfonate), nonionic surfactant (alcohol ethoxylate) and polymer (xanthan gum) were prepared as the aqueous phase. Both counter-current and co-current geometries were tested. Due to the intrinsically unforced, gentle nature of the process, and their strong dependence on wettability, interfacial tension, viscosity and density, such experiments provide valuable insight into some of the governing mechanisms behind ultrasonic stimulation. PMID:17927413

  11. Electro-capillary effects in capillary filling dynamics of electrorheological fluids.

    PubMed

    Dhar, Jayabrata; Ghosh, Uddipta; Chakraborty, Suman

    2015-09-21

    The flow of electrorheological fluids is characterized by an apparent increase in viscosity manifested by the yield stress property of the fluid, which is a function of the applied electric field and the concentration of the suspended solute phase within the dielectric medium. This property of electrorheological fluids generally hinders flow through a capillary if the imposed shear stress is lower than the induced yield stress. This results in a plug-like zone in the flow profile, thus giving the fluid Bingham plastic properties. In the present work, we study such influences of the yield stress on the capillary filling dynamics of an electrorheological fluid by employing a rheologically consistent reduced order formalism. One important feature of the theoretical formalism is its ability to address the intricate interplay between the surface tension and viscous forces, both of which depend sensitively on the electric field. Our analysis reveals that the progress of the capillary front is hindered at an intermediate temporal regime, which is attributable to the increase of the span of the plug-zone across the channel width with time. With a preliminary understanding on the cessation of the capillary front advancement due to the yield stress property of the electrorheological fluids, we further strive to achieve a basic comparison with an experimental study made earlier. Reasonable agreements with the reported data support our theoretical framework. Comprehensive scaling analysis brings further insight to our reported observations over various temporal regimes. PMID:26235842

  12. Open tubular capillary column for the separation of cytochrome C tryptic digest in capillary electrochromatography.

    PubMed

    Ali, Faiz; Cheong, Won Jo

    2015-10-01

    A silica capillary of 50 ?m internal diameter and 500 mm length (416 mm effective length) was chemically modified with 4-(trifluoromethoxy) phenyl isocyanate in the presence of dibutyl tin dichloride as catalyst. Sodium diethyl dithiocarbamate was reacted with the terminal halogen of the bound ligand to incorporate the initiator moiety, and in situ polymerization was performed using a monomer mixture of styrene, N-phenylacrylamide, and methacrylic acid. The resultant open tubular capillary column immobilized with the copolymer layer was used for the separation of tryptic digest of cytochrome C in capillary electrochromatography. The sample was well eluted and separated into many components. The elution patterns of tryptic digest of cytochrome C were studied with respect to pH and water content in the mobile phase. This preliminary study demonstrates that open tubular capillary electrochromatography columns with a modified copolymer layer composed of proper nonpolar and polar units fabricated by reversible addition-fragmentation transfer polymerization can be useful as separation media for proteomic analysis. PMID:26289407

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

    E-print Network

    Miksik, Ivan

    2006-01-01

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

  14. PERMEABILITY OF MUSCLE CAPILLARIES TO EXOGENOUS MYOGLOBIN

    PubMed Central

    Simionescu, Nicolae; Simionescu, Maia; Palade, George E.

    1973-01-01

    Whale skeletal muscle myoglobin (mol wt 17,800; molecular dimensions 25 x 34 x 42 Å) was used as a probe molecule for the pore systems of muscle capillaries. Diaphragms of Wistar-Furth rats were fixed in situ at intervals up to 4 h after the intravenous injection of the tracer, and myoglobin was localized in the tissue by a peroxidase reaction. Gel filtration of plasma samples proved that myoglobin molecules remained in circulation in native monomeric form. At 30–35 s postinjection, the tracer marked ?75% of the plasmalemmal vesicles on the blood front of the endothelium, 15% of those located inside and none of those on the tissue front. At 45 s, the labeling of vesicles in the inner group reached 60% but remained nil for those on the tissue front. Marked vesicles appeared on the latter past 45 s and their frequency increased to ?80% by 60–75 s, concomitantly with the appearance of myoglobin in the pericapillary spaces. Significant regional heterogeneity in initial labeling was found in the different segments of the endothelium (i.e., perinuclear cytoplasm, organelle region, cell periphery, and parajunctional zone). Up to 60 s, the intercellular junctions and spaces of the endothelium were free of myoglobin reaction product; thereafter, the latter was detected in the distal part of the intercellular spaces in concentration generally equal to or lower than that prevailing in the adjacent pericapillary space. The findings indicate that myoglobin molecules cross the endothelium of muscle capillaries primarily via plasmalemmal vesicles. Since a molecule of this size is supposed to exit through both pore systems, our results confirm the earlier conclusion that the plasmalemmal vesicles represent the large pore system; in addition, they suggest that the same structures are, at least in part, the structural equivalent of the small pore system of this type of capillaries. PMID:4696549

  15. Capillary condensation for fluids in spherical cavities

    E-print Network

    Ignacio Urrutia; Leszek Szybisz

    2006-02-03

    The capillary condensation for fluids into spherical nano-cavities is analyzed within the frame of two theoretical approaches. One description is based on a widely used simplified version of the droplet model formulated for studying atomic nuclei. The other, is a more elaborated calculation performed by applying a density functional theory. The agreement between both models is examined and it is shown that a small correction to the simple fluid model improves the predictions. A connection to results previously obtained for planar slits and cylindrical pores is done.

  16. Microfabricated capillary array electrophoresis device and method

    DOEpatents

    Simpson, Peter C.; Mathies, Richard A.; Woolley, Adam T.

    2004-06-15

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  17. Microfabricated capillary array electrophoresis device and method

    DOEpatents

    Simpson, Peter C. (Oakland, CA); Mathies, Richard A. (Moraga, CA); Woolley, Adam T. (Belmont, MA)

    2000-01-01

    A capillary array electrophoresis (CAE) micro-plate with an array of separation channels connected to an array of sample reservoirs on the plate. The sample reservoirs are organized into one or more sample injectors. One or more waste reservoirs are provided to collect wastes from reservoirs in each of the sample injectors. Additionally, a cathode reservoir is also multiplexed with one or more separation channels. To complete the electrical path, an anode reservoir which is common to some or all separation channels is also provided on the micro-plate. Moreover, the channel layout keeps the distance from the anode to each of the cathodes approximately constant.

  18. Subsidence and capillary effects in chalks

    E-print Network

    Delage, Pierre; Cui, Yu Jun

    2008-01-01

    Based on the concepts of the mechanics of unsaturated soils where capillary phenomena arise between the wetting fluid (water) and the non-wetting one (air), the subsidence of chalks containing oil (non-wetting fluid) during water injection (wetting fluid) is analysed. It is shown that the collapse phenomenon of unsaturated soils under wetting provides a physical explanation and a satisfactory prediction of the order of magnitude of the subsidence of the chalk. The use of a well established constitutive model for unsaturated soils allows a description of the hydro-mechanical history of the chalk, from its deposition to the oil exploitation.

  19. Using capillary electrophoresis for failure analysis

    SciTech Connect

    Kelly, R.G.; Scully, H.S.; Stoner, G.E. . Center for Electrochemical Science and Engineering)

    1993-07-01

    Capillary electrophoresis (CE), an advanced solution analysis technique, can be used for failure analysis of corroded components. It has high sensitivity (concentrations as low as parts-per-trillion) and can detect quantitatively a large number of ionic species. CE determined the vapor-phase attack by organic acids, mainly acetic acid, on an electrical equipment enclosure. These acids most likely originated from the seasoning of the oak pallets used to transport the manufactured items, accumulating inside the shrink-wrap film used to bind packages to the pallet.

  20. Capillary electrophoresis-mass spectrometry of carbohydrates

    PubMed Central

    Zaia, Joseph

    2014-01-01

    The development of methods for capillary electrophoresis (CE) with on-line mass spectrometric detection (CE/MS) is driven by the need for accurate, robust and sensitive glycomics analysis for basic biomedicine, biomarker discovery, and analysis of recombinant protein therapeutics. One important capability is to profile glycan mixtures with respect to the patterns of substituents including sialic acids, acetate, sulfate, phosphate, and other groups. There is additional need for an MS-compatible separation system capable of resolving carbohydrate isomers. This review summarizes applications of CS/MS to analysis of carbohydrates, glycoproteins and glycopeptides that have appeared since 2008. Readers are referred to recent comprehensive reviews covering earlier publications. PMID:23386333

  1. Gravimetric capillary method for kinematic viscosity measurements

    NASA Technical Reports Server (NTRS)

    Rosenberger, Franz; Iwan, J.; Alexander, D.; Jin, Wei-Qing

    1992-01-01

    A novel version of the capillary method for viscosity measurements of liquids is presented. Viscosity data can be deduced in a straightforward way from mass transfer data obtained by differential weighing during the gravity-induced flow of the liquid between two cylindrical chambers. Tests of this technique with water, carbon tetrachloride, and ethanol suggest that this arrangement provides an accuracy of about +/- 1 percent. The technique facilitates operation under sealed, isothermal conditions and, thus can readily be applied to reactive and/or high vapor pressure liquids.

  2. Enhancing the Spontaneous Imbibition Process in Naturally Fractured Reservoirs through Wettability Alteration Using Surfactants: Mechanistic Study and Feasibility of Using Biosurfactants Produced from Agriculture Waste Streams

    E-print Network

    Salehi, Mehdi

    2009-01-01

    chemical surfactants on crushed reservoir rocks and reservoir core plugs were generated and compared. The second part of the study focused on the mechanistic study of wettability alteration by surfactants. There are two main mechanisms proposed...

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

    E-print Network

    O'Hanley, Harrison Fagan

    2012-01-01

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

  4. An investigation of wetting phase evaporation from capillary porous matrices

    NASA Astrophysics Data System (ADS)

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

    2009-10-01

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

  5. A Simple Double-Source Model for Interference of Capillaries

    ERIC Educational Resources Information Center

    Hou, Zhibo; Zhao, Xiaohong; Xiao, Jinghua

    2012-01-01

    A simple but physically intuitive double-source model is proposed to explain the interferogram of a laser-capillary system, where two effective virtual sources are used to describe the rays reflected by and transmitted through the capillary. The locations of the two virtual sources are functions of the observing positions on the target screen. An…

  6. Capillary permeability in normal and hypertensive human pregnancy.

    PubMed

    Hunyor, S N; McEniery, P T; Roberts, K A; Bellamy, G R; Roffe, D J; Gallery, E D; Gyory, A Z; Boyce, E S

    1983-01-01

    Capillary permeability (CP) is elevated in late normal pregnancy, when compared to postpartum values. In women with pregnancy associated hypertension (PAH), pregnancy CP levels are not different from postpartum and are less than in normal pregnancy. These changes in capillary permeability are not explained by alterations in serum albumin. PMID:6627750

  7. Capillary electrokinetic separations: Influence of mobile phase composition on performance

    SciTech Connect

    Sepaniak, M.J.; Swaile, D.F.; Powell, A.C.; Cole, R.O.

    1990-01-01

    The composition of the mobile phase employed in capillary zone electrophoresis and the related technique, micellar electrokinetic capillary chromatography, is an important factor in determining separation performance. The influences of ionic salt, surfactant, and organic solvent mobile phase additives on separation efficiency, retention, and elution range are discussed and demonstrated. 23 refs., 2 figs., 2 tabs.

  8. Rapid Screening of Complex Chemical Samples via Capillary Array Analysis

    SciTech Connect

    D. S. Anex; D. W. Neyer

    1998-11-01

    This report is a summary of the results of a two-year Laboratory-Directed Research and Development (LDRD) project that developed instrumentation and methods for capillary array analysis. During the course of this project, a new capillary array electrochromatography instrument was developed to perform eight simultaneous separations and provide complementary chromatographic information from each column on a single sample.

  9. INFLUENCE OF CAPILLARY PRESSURE ON CO2 STORAGE AND MONITORING

    E-print Network

    Santos, Juan

    analyze the sensitivity of the spatial distribution of CO2 and their seismic images due to capillaryINFLUENCE OF CAPILLARY PRESSURE ON CO2 STORAGE AND MONITORING Juan E. Santos Work in collaboration and Univ. Nac. de La Plata #12;Introduction. I CO2 sequestration in suitable geological formations is one

  10. Dynamics of monocytes flowing in a model pulmonary capillary bed

    NASA Astrophysics Data System (ADS)

    Viallat, Annie; Dupire, Jules; Adhesion and Inflammation lab Team

    2012-11-01

    The dynamics of blood cells in the pulmonary bed is an issue for tissue perfusion and host defense. The capillary segments in the lungs are smaller than the size of leukocytes so that most of them change their shape to enter and travel through a capillary pathway. During inflammation, changes in the cytoskeleton of leukocytes may stiffen them, resulting in their massive stop and sequestration within lung capillaries. However, due to difficulties of in vivo studies, little is known about the dynamics of leukocytes in the microcirculation and about the coupling between cellular rheology, capillary geometry and flow. We report the dynamics of monocytes (THP-1 cell line) flowing under constant pressure drop in a periodic network of capillaries that mimics the capillary bed. The analysis of cell entrance in the first segment allows the estimation of effective cellular elasticity, viscosity and cortical tension. Cells then present an unsteady regime, with a non-periodic trajectory, a stretching of their average shape and an increase of their velocity. This regime is interpreted from a parameter equivalent to the Deborah number of the system. Finally, a periodic regime is reached with alternatively left and right turns at capillary bifurcations. The reduced cell velocity is governed by an effective friction coefficient between the cell and the capillary walls. Both transient and final regimes depend on cell deformability, as shown by modifying the cortical actin of the cytoskeleton. This work has been supported by the French Research. National Agency (ANR) under reference ChipCellTrap.

  11. Comment on `Nanoscale water capillary bridges under deeply negative

    E-print Network

    Balibar, Sébastien

    saturated vapor pressure Psat. Because of the cohesion forces between particles, the pressure can evenComment on `Nanoscale water capillary bridges under deeply negative pressure' [Chem. Phys. Lett micro- scope tip and a silicon wafer. They deduced the pressure of liquid water inside the capillary

  12. Thermodynamics of Capillary Rise: Why Is the Meniscus Curved?

    ERIC Educational Resources Information Center

    Henriksson, Ulf; Eriksson, Jan Christer

    2004-01-01

    The thermodynamics of capillary rise is explained as the gravitational elevation of the whole column of liquid caused by the positive connection between the liquid, and the solid wall of the capillary tube. The curvature of the meniscus is ascribed to the maintenance of a physiochemical balance throughout the gravitational column of liquid.

  13. A proposed taxonomy for nailfold capillaries based on their morphology.

    PubMed

    Jones, B F; Oral, M; Morris, C W; Ring, E F

    2001-04-01

    Certain diseases cause permanent changes to the shapes and densities of nailfold capillaries and, therefore, nailfold capillaroscopy is important as a tool for diagnosing and monitoring these diseases. The first aim of the project is to resolve differences in terminology that have developed over the years in previous work. We propose a taxonomy for nailfold capillaries that cover six descriptive classes: cuticulis, open, tortuous, crossed, bushy, and bizarre. The first three are parametric in that they may be distinguished by the ratio of capillary length to width and by the curvature of the capillary limbs. The last three are characterized by their topology; a crossed capillary has a closed area that is not connected to the image background. Bushy and bizarre capillaries have atypical shapes that are characterized by the convex hull of their skeleton. These descriptive classes may be modified according to anomalies in width and length. The second aim is to automate the classification of capillaries by encapsulating the taxonomy in an algorithm; our computer program rivals the most experienced clinicians in classifying capillaries consistently with an overall agreement of 85% with the clinicians' majority view. This was particularly valuable in classifying borderline shapes objectively and consistently. PMID:11370900

  14. Capillary-Pumped Passive Reactor Concept for Space Nuclear Power

    SciTech Connect

    Dr. Thomas F. Lin; Dr. Thomas G. Hughes; Christopher G. Miller

    2008-05-30

    To develop the passively-cooled space reactor concept using the capillary-induced lithium flow, since molten lithium possesses a very favorable surface tension characteristic. In space where the gravitational field is minimal, the gravity-assisted natural convection cooling is not effective nor an option for reactor heat removal, the capillary induced cooling becomes an attractive means of providing reactor cooling.

  15. Strongly nonlinear waves in capillary electrophoresis

    PubMed Central

    Chen, Zhen; Ghosal, Sandip

    2012-01-01

    In capillary electrophoresis, sample ions migrate along a micro-capillary filled with a background electrolyte under the influence of an applied electric field. If the sample concentration is sufficiently high, the electrical conductivity in the sample zone could differ significantly from the background. Under such conditions, the local migration velocity of sample ions becomes concentration dependent resulting in a nonlinear wave that exhibits shock like features. If the nonlinearity is weak, the sample concentration profile, under certain simplifying assumptions, can be shown to obey Burgers’ equation (S. Ghosal and Z. Chen Bull. Math. Biol. 2010 72(8), pg. 2047) which has an exact analytical solution for arbitrary initial condition. In this paper, we use a numerical method to study the problem in the more general case where the sample concentration is not small in comparison to the concentration of background ions. In the case of low concentrations, the numerical results agree with the weakly nonlinear theory presented earlier, but at high concentrations, the wave evolves in a way that is qualitatively different. PMID:23004798

  16. Capillary Liquid Acquisition Device Heat Entrapment

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    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 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.

  17. Capillary surface discontinuities above reentrant corners

    NASA Technical Reports Server (NTRS)

    Korevaar, H. J.

    1982-01-01

    A particular configuration of a vertical capillary tube for which S is the equilibrium interface between two fluids in the presence of a downward pointing gravitational field was investigated. S is the graph a function u whose domain is the (horizontal) cross section gamma of the tube. The mean curvature of S is proportional to its height above a fixed reference plane and lambda is a prescribed constant and may be taken between zero and pi/2. Domains gamma for which us is a bounded function but does not extend continuously to d gamma are sought. Simple domains are found and the behavior of u in those domains is studied. An important comparison principle that has been used in the literature to derive many of the results in capillarity is reviewed. It allows one to deduce the approximate shape of a capillary surface by constructing comparison surfaces with mean curvature and contact angle close to those of the (unknown) solution surface. In the context of nonparametric problems the comparison principle leads to height estimates above and below for the function u. An example from the literature where these height estimates have been used successfully is described. The promised domains for which the bounded u does not extend continuously to the boundary are constructed. The point on the boundary at which u has a jump discontinuity will be the vertext of a re-entrant corner having any interior angle theta pi. Using the comparison principle the behavior of u near this point is studied.

  18. Capillary induced buckling of floating sheets

    NASA Astrophysics Data System (ADS)

    Pineirua, Miguel; Bico, Jose; Roman, Benoit; Menon, Narayanan

    2012-02-01

    When a water droplet is deposited over a thin floating sheet, radial wrinkles appear in the vicinity of the droplet as a result of capillary forces exerted at the contact line [1]. However, determining the stress state at the contact line is still challenging and limits the full description of the wrinkling pattern. In order to avoid this contact line ambiguities, we propose the experimental study of the buckling of a macroscopic annulus floating on the surface of water and submitted to a difference in surface tension between its inner and outer edges. This particular configuration allows to generate radial wrinkles on the membrane with well defined border conditions. The topography of the wrinkled patterns are precisely measured using a synthetic Schlieren technique. Based on the standard buckling theory, we develop scaling laws for the buckling threshold of the annulus as well as for the wave length and radial extension of the wrinkles, which are compared to our experimental results and numerical simulations. [4pt] [1] J. Huang, M. Juszkiewicz, W.H. de Jeu, E. Cerda, T. Emrick, N. Menon, and T.P. Russell. Capillary wrinkling of floating thin polymer films. Science, 317(5838):650-653, 2007.

  19. Computational modelling of microfluidic capillary breakup phenomena

    NASA Astrophysics Data System (ADS)

    Li, Yuan; Sprittles, James; Oliver, Jim

    2013-11-01

    Capillary breakup phenomena occur in microfluidic flows when liquid volumes divide. The fundamental process of breakup is a key factor in the functioning of a number of microfluidic devices such as 3D-Printers or Lab-on-Chip biomedical technologies. It is well known that the conventional model of breakup is singular as pinch-off is approached, but, despite this, theoretical predictions of the global flow on the millimetre-scale appear to agree well with experimental data, at least until the topological change. However, as one approaches smaller scales, where interfacial effects become more dominant, it is likely that such unphysical singularities will influence the global dynamics of the drop formation process. In this talk we develop a computational framework based on the finite element method capable of resolving diverse spatio-temporal scales for the axisymmetric breakup of a liquid jet, so that the pinch-off dynamics can be accurately captured. As well as the conventional model, we discuss the application of the interface formation model to this problem, which allows the pinch-off to be resolved singularity-free, and has already been shown to produce improved flow predictions for related ``singular'' capillary flows.

  20. Critical Velocity in Open Capillary Channel Flows

    NASA Technical Reports Server (NTRS)

    Rosendahl, Uwe; Dreyer, Michael E.; Rath, Hans J.; Motil, Brian; Singh, Bhim S. (Technical Monitor)

    2001-01-01

    We investigate forced liquid flows through open capillary channels with free surfaces experimentally. The experiments were performed under low gravity conditions in the Bremen Drop Tower and on board the sounding rocket TEXUS-37. Open capillary channels (vanes) are used in surface tension tanks to transport the propellant and to provide a flow path for the bubble-free liquid supply to the thrusters. Since the free surfaces can only withstand a certain pressure differential between the liquid and ambient, the flow rate in the channel is limited. The maximum flow rate is achieved when the surfaces collapse and gas is ingested into the outlet. Since experimental and theoretical data of this flow rate limitation is lacking, the safety factors for the application of vanes in surface tension tanks must be unnecessary high. The aim of the investigation is to determine the maximum liquid flow rate and the corresponding critical flow velocity. The characteristic nondimensional parameters, OHNESORGE number, and gap ratio, cover a wide range of usual vanes. For the theoretical approach a one-dimensional momentum balance was set up. The numerical solution yields the maximum volume flux and the position of the free surface in good agreement with the experiments.

  1. Correlation between corrosion performance and surface wettability in ZrTiCuNiBe bulk metallic glasses

    NASA Astrophysics Data System (ADS)

    Wang, Y. B.; Li, H. F.; Zheng, Y. F.; Wei, S. C.; Li, M.

    2010-06-01

    The corrosion properties of two Zr-based bulk metallic glass, Zr41Ti14Cu12Ni10Be23 (LM1) and Zr44Ti11Cu10Ni10Be25 (LM1b) were investigated by electrochemical measurements in simulated body fluid with pH value 7.4. With much lower current density and higher impedance values, as well as higher pitting potential, LM1b showed superior corrosion resistance to LM1. Under identical sample preparation and testing conditions, the difference in corrosion performance is found to relate closely to their surface wettability difference, as contact angle tests showed that LM1b is more hydrophobic than LM1. The excess free volume was measured and found having a close correlation with the wettability or the surface energy.

  2. Dynamic wettability alteration in immiscible two-phase flow in porous media: Effect on transport properties and critical slowing down

    E-print Network

    Flovik, Vegard; Hansen, Alex

    2015-01-01

    The change in contact angles due to the injection of low salinity water or any other wettability altering agent in an oil-rich porous medium is modeled by a network model of disordered pores transporting two immiscible fluids. We introduce a dynamic wettability altering mechanism, where the time dependent wetting property of each pore is determined by the cumulative flow of water through it. Simulations are performed to reach steady-state for different possible alterations in the wetting angle ($\\theta$). We find that deviation from oil-wet conditions re-mobilizes the stuck clusters and increases the oil fractional flow. However, the rate of increase in the fractional flow depends strongly on $\\theta$ and as $\\theta\\to 90^\\circ$, a critical angle, the system shows critical slowing down which is characterized by two dynamic critical exponents.

  3. Direct measurement of capillary blood pressure in the human lip

    NASA Technical Reports Server (NTRS)

    Parazynski, S. E.; Tucker, B. J.; Aratow, M.; Crenshaw, A.; Hargens, A. R.

    1993-01-01

    In this study, we developed and tested a new procedure for measuring microcirculatory blood pressures above heart level in humans. Capillary and postcapillary venule blood pressures were measured directly in 13 human subjects by use of the servonulling micropressure technique adapted for micropuncture of lip capillaries. Pressure waveforms were recorded in 40 separate capillary vessels and 14 separate postcapillary venules over periods ranging from 5 to 64 s. Localization and determination of capillary and postcapillary vessels were ascertained anatomically before pressure measurements. Capillary pressure was 33.2 +/- 1.5 (SE) mm Hg in lips of subjects seated upright. Repeated micropunctures of the same vessel gave an average coefficient of variation of 0.072. Postcapillary venule pressure was 18.9 +/- 1.6 mm Hg. This procedure produces a direct and reproducible means of measuring microvascular blood pressures in a vascular bed above heart level in humans.

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  5. A short-range ordered-disordered transition of a NiOOH/Ni(OH)2 pair induces switchable wettability

    NASA Astrophysics Data System (ADS)

    Chang, Ya-Huei; Hau, Nga Yu; Liu, Chang; Huang, Yu-Ting; Li, Chien-Cheng; Shih, Kaimin; Feng, Shien-Ping

    2014-11-01

    By virtue of its amorphous structure with a short-range order feature, the inorganic nanoporous nickel oxyhydroxide (NiOOH) can reversibly and rapidly switch wettability by alternate treatments of environmental chamber (superhydrophobic) and UV/ozone (superhydrophilic). The switchable mechanism of the NiOOH/Ni(OH)2 pair arising from its exceptional intrinsic short-range order-disorder transition together with chemical composition change is highlighted for the first time, which significantly differs from the current stimuli-responsive materials. This distinct multifunctional thin film not only possesses reversible wettability but also is optically patternable/repairable and electrically conductive, which could be applicable in the manufacturing of various micro- and nanostructures. We demonstrate this potential in the rewritable two-dimensional (2D) microfluidic channels and wetting-contrast enhanced selective electroplating.By virtue of its amorphous structure with a short-range order feature, the inorganic nanoporous nickel oxyhydroxide (NiOOH) can reversibly and rapidly switch wettability by alternate treatments of environmental chamber (superhydrophobic) and UV/ozone (superhydrophilic). The switchable mechanism of the NiOOH/Ni(OH)2 pair arising from its exceptional intrinsic short-range order-disorder transition together with chemical composition change is highlighted for the first time, which significantly differs from the current stimuli-responsive materials. This distinct multifunctional thin film not only possesses reversible wettability but also is optically patternable/repairable and electrically conductive, which could be applicable in the manufacturing of various micro- and nanostructures. We demonstrate this potential in the rewritable two-dimensional (2D) microfluidic channels and wetting-contrast enhanced selective electroplating. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05261g

  6. Dip-in Indicators for Visual Differentiation of Fuel Mixtures Based on Wettability of Fluoroalkylchlorosilane-Coated Inverse Opal Films.

    PubMed

    Sedighi, Abootaleb; Qiu, Shuang; Wong, Michael C K; Li, Paul C H

    2015-12-30

    We have developed the dip-in indicator based on the inverse opal film (IOF) for visual differentiation of organic liquid mixtures, such as oil/gasoline or ethanol/gasoline fuel mixtures. The IOF consists of a three-dimensional porous structure with a highly ordered periodic arrangement of nanopores. The specularly reflected light at the interface of the nanopores and silica walls contributes to the structural color of the IOF film. This color disappears when the nanopores are infiltrated by a liquid with a similar refractive index to silica. The disappearance of the structural color provides a means to differentiate various liquid fuel mixtures based on their wettability of the nanopores in the IOF-based indicators. For differentiation of various liquid mixtures, we tune the wettability threshold of the indicator in such a way that it is wetted (color disappears) by one liquid but is not wetted by the other (color remains). Although colorimetric differentiation of liquids based on IOF wettability has been reported, differentiation of highly similar liquid mixtures require complicated readout approaches. It is known that the IOF wettability is controlled by multiple surface properties (e.g., oleophobicity) and structural properties (e.g., neck angle and film thickness) of the nanostructure. Therefore, we aim to exploit the combined tuning of these properties for differentiation of fuel mixtures with close compositions. In this study, we have demonstrated that, for the first time, the IOF-based dip-in indicator is able to detect a slight difference in the fuel mixture composition (i.e., 0.4% of oil content). Moreover, the color/no-color differentiation platform is simple, powerful, and easy-to-read. This platform makes the dip-in indicator a promising tool for authentication and determination of fuel composition at the point-of-purchase or point-of-use. PMID:26634404

  7. Electrophoretically mediated microanalysis for in-capillary electrical cell lysis and fast enzyme quantification by capillary electrophoresis.

    PubMed

    Nehmé, Hala; Nehmé, Reine; Lafite, Pierre; Duverger, Eric; Routier, Sylvain; Morin, Philippe

    2013-11-01

    In this study, a novel capillary electrophoresis (CE)-based enzymatic assay was developed to evaluate enzymatic activity in whole cells. ?-Galactosidase expression was used as an example, as it is a biomarker for assessing replicative senescence in mammalian cells. It catalyzes the hydrolysis of para-nitrophenyl-?-D-galactopyranoside (PNPG) into para-nitrophenol (PNP). The CE-based assay consisted of four main steps: (1) hydrodynamic injection of whole intact cells into the capillary, (2) in-capillary lysis of these cells by using pulses of electric field (electroporation), (3) in-capillary hydrolysis of PNPG by the ?-galactosidase--released from the lysed cells--by the electrophoretically mediated microanalysis (EMMA) approach, and (4) on-line detection and quantification of the PNP formed. The developed method was applied to Escherichia coli as well as to human keratinocyte cells at different replicative stages. Results obtained by CE were in excellent agreement with those obtained from off-line cell lysates which proves the efficiency of the in-capillary approach developed. This work shows for the first time that cell membranes can be disrupted in-capillary by electroporation and that the released enzyme can be subsequently quantified in the same capillary. Enzyme quantification in cells after their in-capillary lysis has never been conducted by CE. The developed CE approach is automated, economic, eco-friendly, and simple to conduct. It has attractive applications in bacteria or human cells for early disease diagnostics or insights for development in biology. PMID:24057022

  8. Complementary actions

    PubMed Central

    Sartori, Luisa; Betti, Sonia

    2015-01-01

    Complementary colors are color pairs which, when combined in the right proportions, produce white or black. Complementary actions refer here to forms of social interaction wherein individuals adapt their joint actions according to a common aim. Notably, complementary actions are incongruent actions. But being incongruent is not sufficient to be complementary (i.e., to complete the action of another person). Successful complementary interactions are founded on the abilities: (i) to simulate another person’s movements, (ii) to predict another person’s future action/s, (iii) to produce an appropriate incongruent response which differ, while interacting, with observed ones, and (iv) to complete the social interaction by integrating the predicted effects of one’s own action with those of another person. This definition clearly alludes to the functional importance of complementary actions in the perception–action cycle and prompts us to scrutinize what is taking place behind the scenes. Preliminary data on this topic have been provided by recent cutting-edge studies utilizing different research methods. This mini-review aims to provide an up-to-date overview of the processes and the specific activations underlying complementary actions. PMID:25983717

  9. Selective Area Modification of Silicon Surface Wettability by Pulsed UV Laser Irradiation in Liquid Environment.

    PubMed

    Liu, Neng; Moumanis, Khalid; Dubowski, Jan J

    2015-01-01

    The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of biosensing devices. We report on a protocol of using KrF and ArF lasers irradiating Si (001) samples immersed in a liquid environment with low number of pulses and operating at moderately low pulse fluences to induce Si wettability modification. Wafers immersed for up to 4 hr in a 0.01% H2O2/H2O solution did not show measurable change in their initial contact angle (CA) ~75°. However, the 500-pulse KrF and ArF lasers irradiation of such wafers in a microchamber filled with 0.01% H2O2/H2O solution at 250 and 65 mJ/cm(2), respectively, has decreased the CA to near 15°, indicating the formation of a superhydrophilic surface. The formation of OH-terminated Si (001), with no measurable change of the wafer's surface morphology, has been confirmed by X-ray photoelectron spectroscopy and atomic force microscopy measurements. The selective area irradiated samples were then immersed in a biotin-conjugated fluorescein-stained nanospheres solution for 2 hr, resulting in a successful immobilization of the nanospheres in the non-irradiated area. This illustrates the potential of the method for selective area biofunctionalization and fabrication of advanced Si-based biosensing architectures. We also describe a similar protocol of irradiation of wafers immersed in methanol (CH3OH) using ArF laser operating at pulse fluence of 65 mJ/cm(2) and in situ formation of a strongly hydrophobic surface of Si (001) with the CA of 103°. The XPS results indicate ArF laser induced formation of Si-(OCH3)x compounds responsible for the observed hydrophobicity. However, no such compounds were found by XPS on the Si surface irradiated by KrF laser in methanol, demonstrating the inability of the KrF laser to photodissociate methanol and create -OCH3 radicals. PMID:26575362

  10. WETTABILITY AND IMBIBITION: MICROSCOPIC DISTRIBUTION OF WETTING AND ITS CONSEQUENCES AT THE CORE AND FIELD SCALES

    SciTech Connect

    Jill S. Buckley; Norman R. Morrow; Chris Palmer; Purnendu K. Dasgupta

    2003-02-01

    The questions of reservoir wettability have been approached in this project from three directions. First, we have studied the properties of crude oils that contribute to wetting alteration in a reservoir. A database of more than 150 different crude oil samples has been established to facilitate examination of the relationships between crude oil chemical and physical properties and their influence on reservoir wetting. In the course of this work an improved SARA analysis technique was developed and major advances were made in understanding asphaltene stability including development of a thermodynamic Asphaltene Solubility Model (ASM) and empirical methods for predicting the onset of instability. The CO-Wet database is a resource that will be used to guide wettability research in the future. The second approach is to study crude oil/brine/rock interactions on smooth surfaces. Contact angle measurements were made under controlled conditions on mica surfaces that had been exposed to many of the oils in the CO-Wet database. With this wealth of data, statistical tests can now be used to examine the relationships between crude oil properties and the tendencies of those oils to alter wetting. Traditionally, contact angles have been used as the primary wetting assessment tool on smooth surfaces. A new technique has been developed using an atomic forces microscope that adds a new dimension to the ability to characterize oil-treated surfaces. Ultimately we aim to understand wetting in porous media, the focus of the third approach taken in this project. Using oils from the CO-Wet database, experimental advances have been made in scaling the rate of imbibition, a sensitive measure of core wetting. Application of the scaling group to mixed-wet systems has been demonstrated for a range of core conditions. Investigations of imbibition in gas/liquid systems provided the motivation for theoretical advances as well. As a result of this project we have many new tools for studying wetting at microscopic and macroscopic scales and a library of well-characterized fluids for use in studies of crude oil/brine/rock interactions.

  11. Biomimetic Transferable Surface for a Real Time Control over Wettability and Photoerasable Writing with Water Drop Lens

    PubMed Central

    Zillohu, Ahnaf Usman; Abdelaziz, Ramzy; Homaeigohar, Shahin; Krasnov, Igor; Müller, Martin; Strunskus, Thomas; Elbahri, Mady

    2014-01-01

    We demonstrate a transferable device that can turn wettability of surfaces to sticky or slippy, as per requirement. It is composed of polymeric yarn with a fibrous structure, which can be lifted and placed on any surface to render it the unique wettability properties. We introduce Polyvinylidenefluoride (PVDF) random fiber as biomimetic rose petal surface. When it is decorated with PVDF nanofibers yarns, the random mesh transform from rose petal sticky state into grass leaf slippy state. When it is placed on sticky, hydrophilic metal coin, it converts the surface of the coin to super hydrophobic. Adjustments in the yarn system, like interyarn spacing, can be done in real time to influence its wettability, which is a unique feature. Next, we load the polymer with a photochromic compound for chemical restructuring. It affects the sliding angle of water drop and makes the fibers optically active. We also demonstrate a “water droplets lens” concept that enables erasable writing on photochromic rose petal sticky fibrous surface. The droplet on a highly hydrophobic surface acts as a ball lens to concentrate light onto a hot spot; thereby we demonstrate UV light writing with water lenses and visible light erasing. PMID:25491016

  12. Structure and wettability property of the growth and nucleation surfaces of thermally treated freestanding CVD diamond films

    NASA Astrophysics Data System (ADS)

    Pei, Xiaoqiang; Cheng, Shaoheng; Ma, Yibo; Wu, Danfeng; Liu, Junsong; Wang, Qiliang; Yang, Yizhou; Li, Hongdong

    2015-08-01

    This paper reports the surface features and wettability properties of the (1 0 0)-textured freestanding chemical vapor deposited (CVD) diamond films after thermal exposure in air at high temperature. Thermal oxidation at proper conditions eliminates selectively nanodiamonds and non-diamond carbons in the films. The growth side of the films contains (1 0 0)-oriented micrometer-sized columns, while its nucleation side is formed of nano-sized tips. The examined wettability properties of the as-treated diamond films reveal a hydrophilicity and superhydrophilicity on the growth surface and nucleation surface, respectively, which is determined by oxygen termination and geometry structure of the surface. When the surface termination is hydrogenated, the wettability of nucleation side converted from superhydrophilicity to high hydrophobicity, while the hydrophilicity of the growth side does not change significantly. The findings open a possibility for realizing freestanding diamond films having not only novel surface structures but also multifunction applications, especially proposed on the selected growth side or nucleation side in one product.

  13. Improved wettability and adhesion of polylactic acid/chitosan coating for bio-based multilayer film development

    NASA Astrophysics Data System (ADS)

    Gartner, Hunter; Li, Yana; Almenar, Eva

    2015-03-01

    The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (?), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The ? of the PLA/CS blend shifted to a lower value (41-35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228-303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

  14. Biomimetic Transferable Surface for a Real Time Control over Wettability and Photoerasable Writing with Water Drop Lens

    NASA Astrophysics Data System (ADS)

    Zillohu, Ahnaf Usman; Abdelaziz, Ramzy; Homaeigohar, Shahin; Krasnov, Igor; Müller, Martin; Strunskus, Thomas; Elbahri, Mady

    2014-12-01

    We demonstrate a transferable device that can turn wettability of surfaces to sticky or slippy, as per requirement. It is composed of polymeric yarn with a fibrous structure, which can be lifted and placed on any surface to render it the unique wettability properties. We introduce Polyvinylidenefluoride (PVDF) random fiber as biomimetic rose petal surface. When it is decorated with PVDF nanofibers yarns, the random mesh transform from rose petal sticky state into grass leaf slippy state. When it is placed on sticky, hydrophilic metal coin, it converts the surface of the coin to super hydrophobic. Adjustments in the yarn system, like interyarn spacing, can be done in real time to influence its wettability, which is a unique feature. Next, we load the polymer with a photochromic compound for chemical restructuring. It affects the sliding angle of water drop and makes the fibers optically active. We also demonstrate a ``water droplets lens'' concept that enables erasable writing on photochromic rose petal sticky fibrous surface. The droplet on a highly hydrophobic surface acts as a ball lens to concentrate light onto a hot spot; thereby we demonstrate UV light writing with water lenses and visible light erasing.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  16. New concept for coal wettability evaluation and modulation. Technical progress report, January 1, 1995--March 31, 1995

    SciTech Connect

    Hu, Weibai

    1995-12-31

    This project is concerned with the new concept for coal surface wettability and floatability evaluation and modulation. The objective of the work is study the fundamental surface chemistry features about the evaluation of the surface wettability and floatability of coal and pyrite, and establish a new separation strategy which could contribute to advanced coal-cleaning for premium fuel application. During this quarter, the mini-flotation cell tests are conducted to study floatability of coal and pyrite. The three coals, coal pyrite and Colorado mineral pyrite samples are used in these tests. The kinetic floatability of the five samples have been tested without collector, with 3% and 6% NaCl solution. The test results have shown that there are good agreement between the experimental observation and the theoretical hypothesis about the new concept about the surface wettability and floatability of the coal and pyrite. The experimental results indicate that the coal floatability increase rapidly, but the floatability of coal pyrite and mineral pyrite are not change significantly with the addition of NaCl in flotation. It can be seen that the coal floatability increase as NaCl concentration increase. 14 figs., 5 tabs.

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

    PubMed Central

    2011-01-01

    Nanoscale surface manipulation technique to control the surface roughness and the wettability is a challenging field for performance enhancement in boiling heat transfer. In this study, micro-nano hybrid structures (MNHS) with hierarchical geometries that lead to maximizing of surface area, roughness, and wettability are developed for the boiling applications. MNHS structures consist of micropillars or microcavities along with nanowires having the length to diameter ratio of about 100:1. MNHS is fabricated by a two-step silicon etching process, which are dry etching for micropattern and electroless silicon wet etching for nanowire synthesis. The fabrication process is readily capable of producing MNHS covering a wafer-scale area. By controlling the removal of polymeric passivation layers deposited during silicon dry etching (Bosch process), we can control the geometries for the hierarchical structure with or without the thin hydrophobic barriers that affect surface wettability. MNHS without sidewalls exhibit superhydrophilic behavior with a contact angle under 10°, whereas those with sidewalls preserved by the passivation layer display more hydrophobic characteristics with a contact angle near 60°. PMID:21711859

  18. Wettability behavior of special microscale ZnO nail-coated mesh films for oil-water separation.

    PubMed

    Du, Xin; Huang, Xing; Li, Xiaoyu; Meng, Xiangmin; Yao, Lin; He, Junhui; Huang, Hongwei; Zhang, Xueji

    2015-11-15

    The surface free energy and geometrical structure are two important factors to govern the surface wettability. However, the design and simple synthesis of materials with specific surface free energy and geometrical structure, and their elaborate regulations are still a key challenge. Herein, through one-step thermal evaporation method, we successfully synthesized aligned arrays of highly crystallized ZnO with modulated nail structures on the stainless steel meshes for the first time. Owing to the decoration of [0001] oriented nail structures, the wire surface of meshes were indeed enclosed by the ZnO (0002) facets, which had the lowest surface energy in wurtzite structure. Under no any further modifications, just by regulating the nail structure and density as well as the mesh pore sizes, we not only obtained ZnO nail-coated mesh with hydrophobic, oleophilic (oil penetration), and underwater oleophilic properties, but also fabricated one with hydrophilic (water penetration), oleophilic (oil penetration), and underwater superoleophobic properties. Furthermore, interestingly, the separation of oil and water mixture was realized by utilizing two ZnO-nail coated meshes with different wettability. The underlying mechanism was investigated and discussed in the work. Therefore, our study provides interesting insight into the design of novel functional films with desired surface wettability for the separation of oil-water mixture. PMID:26207588

  19. Uniform Laser Excitation And Detection In Capillary Array Electrophoresis System And Method.

    DOEpatents

    Li, Qingbo (State College, PA); Zhou, Songsan (Ferguson, PA); Liu, Changsheng (State College, PA)

    2003-10-07

    A capillary electrophoresis system comprises capillaries positioned in parallel to each other forming a plane. The capillaries are configured to allow samples to migrate. A light source is configured to illuminate the capillaries and the samples therein. This causes the samples to emit light. A lens is configured to receive the light emitted by the samples and positioned directly over a first group of the capillaries and obliquely over a second group of the capillaries. The light source is further configured to illuminate the second group of capillaries more than the first group of the capillaries such that amount of light received by the lens from the first group of capillaries is substantially identical to amount of light received from the second group of capillaries when an identical amount of the samples is migrating through the first and second group capillaries.

  20. Capillary test specimen, system, and methods for in-situ visualization of capillary flow and fillet formation

    DOEpatents

    Hall, Aaron C. (Albuquerque, NM); Hosking, F. Michael (Albuquerque, NM),; Reece, Mark (Albuquerque, NM)

    2003-06-24

    A capillary test specimen, method, and system for visualizing and quantifying capillary flow of liquids under realistic conditions, including polymer underfilling, injection molding, soldering, brazing, and casting. The capillary test specimen simulates complex joint geometries and has an open cross-section to permit easy visual access from the side. A high-speed, high-magnification camera system records the location and shape of the moving liquid front in real-time, in-situ as it flows out of a source cavity, through an open capillary channel between two surfaces having a controlled capillary gap, and into an open fillet cavity, where it subsequently forms a fillet on free surfaces that have been configured to simulate realistic joint geometries. Electric resistance heating rapidly heats the test specimen, without using a furnace. Image-processing software analyzes the recorded images and calculates the velocity of the moving liquid front, fillet contact angles, and shape of the fillet's meniscus, among other parameters.

  1. Erection pattern and section-wise wettability of honeybee glossal hairs in nectar feeding.

    PubMed

    Wu, Jianing; Zhu, Rengao; Yan, Shaoze; Yang, Yunqiang

    2015-03-01

    The honeybee's tongue (glossa) is covered with bushy hairs and resembles a mop or a brush. We examined the dimensions of glossal hairs of the Italian honeybee (Apis mellifera ligustica) and found that the average length of hairs increased from the proximal segment to the distal end. The glossal dynamic surface of a honeybee in drinking cycles was captured by a specially designed high-speed camera system, and we discovered that the glossal hairs erected rhythmically when drinking nectar; specifically, hairs on the proximal segment erected earlier than those on the distal end of a honeybee's tongue, which was identified as the phenomenon of asynchronous hair erection. Moreover, by measuring the wettability of the tongue, we found that the flabellum was the most hydrophilic and the root of the tongue was hardest to be wetted. According to our observations, we suggest that the honeybee has an optimal hair-erection pattern that could balance nectar intake and viscous drag. These results will be helpful to understand the liquid-feeding mechanism of honeybees, especially the role of erectable glossal hairs. PMID:25573821

  2. Zwitter-wettability and antifogging coatings with frost-resisting capabilities.

    PubMed

    Lee, Hyomin; Alcaraz, Maria L; Rubner, Michael F; Cohen, Robert E

    2013-03-26

    Antifogging coatings with hydrophilic or even superhydrophilic wetting behavior have received significant attention due to their ability to reduce light scattering by film-like condensation. However, under aggressive fogging conditions, these surfaces may exhibit frost formation or excess and nonuniform water condensation, which results in poor optical performance of the coating. In this paper, we show that a zwitter-wettable surface, a surface that has the ability to rapidly absorb molecular water from the environment while simultaneously appearing hydrophobic when probed with water droplets, can be prepared by using hydrogen-bonding-assisted layer-by-layer (LbL) assembly of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA). An additional step of functionalizing the nano-blended PVA/PAA multilayer with poly(ethylene glycol methyl ether) (PEG) segments produced a significantly enhanced antifog and frost-resistant behavior. The addition of the PEG segments was needed to further increase the nonfreezing water capacity of the multilayer film. The desirable high-optical quality of these thin films arises from the nanoscale control of the macromolecular complexation process that is afforded by the LbL processing scheme. An experimental protocol that not only allows for the exploration of a variety of aggressive antifogging challenges but also enables quantitative analysis of the antifogging performance via real-time monitoring of transmission levels as well as image distortion is also described. PMID:23360374

  3. Simulation of microdroplet manipulation on flat surface actuated by wettability gradient using dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Hu, Guohui; Zhou, Zhewei

    2011-11-01

    A particle based mesoscopic methodology called dissipative particle dynamics (DPD) is utilized to simulate the manipulation (translation and coalescence) of micro-droplets in planar microfluidic chips with gradients of wettability. The three dimensional velocity field of a moving droplet propelled by wetting gradient is presented, which shows that the liquid spreads downwards onto substrate in the front area while it converges upwards in the back. The flow structure reveals that the drop moves in a combination of rolling and translation, and the rotation could be dominant when the contact angle is bigger than about 110°. The increasing of the gradient steepness and the size of droplet, as well as the magnitude of thermal fluctuation, is capable to significantly accelerate the movement for a sub-micrometer droplet. The liquid mixing in coalescence of two droplets is investigated as well. It is found that the process of mixing consists of two stages -- a rapid active mixing through convective mass transfer and then a slow passive mixing through diffusion, which is consistent with previous experiment. Results also indicate that the thermal fluctuation is helpful to promote the coalescence and liquid mixing. The work was supported by the NSF of China (Grant No. 10872122).

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

    PubMed

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

    2014-05-28

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

  5. Activation and deformation of immobilized lipase on self-assembled monolayers with tailored wettability.

    PubMed

    Chen, Peng-Cheng; Huang, Xiao-Jun; Xu, Zhi-Kang

    2015-05-28

    In this work, lipase from Candida rugosa (CRL) was immobilized on self-assembled monolayers (SAMs) with various wettabilities ranging from highly hydrophilic to highly hydrophobic by adsorption in order to clearly elucidate the interfacial activation character of lipases. The SAMs were made of 11-hydroxyundecane-1-thiol and 1-dodecanethiol. The adsorption behavior was monitored in situ by quartz crystal microbalance with dissipation (QCM-D), and the enzyme binding constants indicated a stronger affinity between CRL and more hydrophobic surfaces. Atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the morphologies of the adsorbed lipases. Amide I band attenuated total reflection/Fourier transformed infrared (ART/FTIR) spectroscopy showed an increasing fraction of intermolecular ?-sheet content on surfaces with higher hydrophilicities. Moreover, liquid chromatography (LC) verified that the activity of CRL adsorbed on a hydrophobic surface was higher than that of CRL adsorbed on a hydrophilic surface. This work related the enzyme activity to the substrate properties, adsorption behavior, distribution, and morphology of lipases, helping to achieve the external control of both the immobilization process and enzyme utilization. PMID:25929434

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

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

    SciTech Connect

    Jill S. Buckley; Norman R. Morrow

    2002-12-01

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

  8. Role of surface oxygen-to-metal ratio on the wettability of rare-earth oxides

    SciTech Connect

    Khan, Sami; Varanasi, Kripa K.; Azimi, Gisele; Yildiz, Bilge

    2015-02-09

    Hydrophobic surfaces that are robust can have widespread applications in drop-wise condensation, anti-corrosion, and anti-icing. Recently, it was shown that the class of ceramics comprising the lanthanide series rare-earth oxides (REOs) is intrinsically hydrophobic. The unique electronic structure of the rare-earth metal atom inhibits hydrogen bonding with interfacial water molecules resulting in a hydrophobic hydration structure where the surface oxygen atoms are the only hydrogen bonding sites. Hence, the presence of excess surface oxygen can lead to increased hydrogen bonding and thereby reduce hydrophobicity of REOs. Herein, we demonstrate how surface stoichiometry and surface relaxations can impact wetting properties of REOs. Using X-ray Photoelectron Spectroscopy and wetting measurements, we show that freshly sputtered ceria is hydrophilic due to excess surface oxygen (shown to have an O/Ce ratio of ?3 and a water contact angle of ?15°), which when relaxed in a clean, ultra-high vacuum environment isolated from airborne contaminants reaches close to stoichiometric O/Ce ratio (?2.2) and becomes hydrophobic (contact angle of ?104°). Further, we show that airborne hydrocarbon contaminants do not exclusively impact the wetting properties of REOs, and that relaxed REOs are intrinsically hydrophobic. This study provides insight into the role of surface relaxation on the wettability of REOs.

  9. Superwetting Surfaces under Different Media: Effects of Surface Topography on Wettability.

    PubMed

    Zhang, Pengchao; Wang, Shasha; Wang, Shutao; Jiang, Lei

    2015-04-24

    Superwetting surfaces in air, such as superhydrophobic and superoleophobic surfaces that are governed by surface chemical compositions and surface topographies, are one of the most extensively studied topics in this field. However, it is not well-understood how surface topographies affect the behaviors of immiscible liquids and gases under other kinds of media, although it is significant in diverse fields. The main aim of this work is to systematically investigate the wetting behaviors of liquids (water and oil) and gas (air) on silicon surfaces with different topographies (i.e., smooth, micro, nano, and micro-/nanostructures) under various media (i.e., air, water, and oil). The contact angles, as well as contact-angle hysteresis, sliding angles, and adhesive forces, were utilized to evaluate the wettability of these surfaces. As a result, the microstructured surfaces typically exhibit high contact-angle hysteresis, high sliding angles, and high adhesive forces, whereas the micro-/nanostructured surfaces display low contact-angle hysteresis, low sliding angles, and low adhesive forces, even if they have high (>150°) and similar contact angles. Furthermore, when transferring the same surface from one kind of medium to another, different superwetting states can be reversibly switched. PMID:25504764

  10. Early osseointegration driven by the surface chemistry and wettability of dental implants

    PubMed Central

    SARTORETTO, Suelen Cristina; ALVES, Adriana Terezinha Neves Novellino; RESENDE, Rodrigo Figueiredo Britto; CALASANS-MAIA, José; GRANJEIRO, José Mauro; CALASANS-MAIA, Mônica Diuana

    2015-01-01

    Objective The objective of this study was to investigate the impact of two different commercially available dental implants on osseointegration. The surfaces were sandblasting and acid etching (Group 1) and sandblasting and acid etching, then maintained in an isotonic solution of 0.9% sodium chloride (Group 2). Material and Methods X-ray photoelectron spectroscopy (XPS) was employed for surface chemistry analysis. Surface morphology and topography was investigated by scanning electron microscopy (SEM) and confocal microscopy (CM), respectively. Contact angle analysis (CAA) was employed for wetting evaluation. Bone-implant-contact (BIC) and bone area fraction occupied (BAFO) analysis were performed on thin sections (30 ?m) 14 and 28 days after the installation of 10 implants from each group (n=20) in rabbits’ tibias. Statistical analysis was performed by ANOVA at the 95% level of significance considering implantation time and implant surface as independent variables. Results Group 2 showed 3-fold less carbon on the surface and a markedly enhanced hydrophilicity compared to Group 1 but a similar surface roughness (p>0.05). BIC and BAFO levels in Group 2 at 14 days were similar to those in Group 1 at 28 days. After 28 days of installation, BIC and BAFO measurements of Group 2 were approximately 1.5-fold greater than in Group 1 (p<0.05). Conclusion The surface chemistry and wettability implants of Group 2 accelerate osseointegration and increase the area of the bone-to-implant interface when compared to those of Group 1. PMID:26221922

  11. Enhancement of Wettability of Aluminum Based Silicon Carbide Reinforced Particulate Metal Matrix Composite

    NASA Astrophysics Data System (ADS)

    Singh, V. K.; Chauhan, Sakshi; Gope, P. C.; Chaudhary, A. K.

    2015-04-01

    Lately, materials research has shifted to composite materials from monolithic, adjusting to the global need for light weight, low cost, quality, and high performance in structural materials. Every effort aims to develop a material which can be appropriate for various industry and machinery purpose. In the present study, a modest attempt has been made to develop cast aluminum based silicon carbide (SiC) particulate metal matrix composite (MMC) and worked upon to raise the wettability factor between the matrix and dispersion phase. Magnesium (Mg) is used as wetting agent. It works by scavenging the oxygen from dispersoids surface and thinning the gas layer around dispersoids and this is done by forming MgO or MgAl2O4 or both according to concentration of Magnesium added. Mg2Si is the compound responsible for strengthening. The combination of aluminum and magnesium seems to have synergetic effect on wetting and give appropriate strength. All mechanical properties obtained are well correlated with microstructure obtained by Scanning electron micrograph. Differential thermal analysis (DTA) and thermo gravimetric analysis (TGA) also justified the results obtained in present investigations.

  12. Biomimetic Submicroarrayed Cross-Linked Liquid Crystal Polymer Films with Different Wettability via Colloidal Lithography.

    PubMed

    Zhan, Yuanyuan; Zhao, Jianqiang; Liu, Wendong; Yang, Bai; Wei, Jia; Yu, Yanlei

    2015-11-18

    Photoresponsive cross-linked liquid crystal polymer (CLCP) films with different surface topographies, submicropillar arrays, and submicrocone arrays were fabricated through colloidal lithography technique by modulating different types of etching masks. The prepared submicropillar arrays were uniform with an average pillar diameter of 250 nm and the cone bottom diameter of the submicrocone arrays was about 400 nm, which are much smaller than previously reported CLCP micropillars. More interestingly, these two species of films with the same chemical structure represented completely different wetting behavior of water adhesion and mimicked rose petal and lotus leaf, respectively. Both the submicropillar arrayed film and the submicrocone arrayed film exhibited superhyrophobicity with a water contact angle (CA) value of 144.0 ± 1.7° and 156.4 ± 1.2°, respectively. Meanwhile, the former demonstrated a very high sliding angle (SA) greater than 90°, and thus, the water droplet was pinned on the surface as rose petal. On the contrary, the SA of the submicrocone arrayed CLCP film consisting of micro- and nanostructure was only 3.1 ± 2.0°, which is as low as that of lotus leaf. Furthermore, the change on the wettability of the films was also investigated under alternating irradiation of visible light with two different wavelengths, blue light and green light. PMID:26509215

  13. The effect of bias voltage on the morphology and wettability of plasma deposited titanium oxide films

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Li, Yan; Guo, Kai; Zhang, Jing

    2008-02-01

    Hydrophobic and hydrophilic films with titanium oxide inside were grown by radio frequency plasma enhanced chemical vapor deposition (RF--PECVD) on glass substrates. Bias voltage was used as an assistant for the deposition process. And a comparison was made between with and without the bias voltage. Titanium tetraisopropoxide (TTIP-Ti (OC 3H 7) 4) was used as the precursor compound. Film wettability was tested by water contact angle measurement (CAM). The water contact angle (WAC) of the film deposited in plasma without biased voltage was greater than 145°, while the WAC of the film deposited in plasma with biased voltage was less than 30°. The morphology of the deposited films was observed by scanning electron microscope (SEM). It is found that the films grown without bias voltage were covered with lots of nano grain and pores, but the surface of the films deposition with bias voltage was much dense. The chemical structure and property of the deposited films were analyzed by Fourier-transformed infrared spectroscopy (FTIR), while the plasma phase was investigated by optical emission spectroscopy (OES).

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

  15. Effect of annealing temperature on wettability of TiO2 nanotube array films

    PubMed Central

    2014-01-01

    Highly ordered TiO2 nanotube array (TN) films were prepared by anodization of titanium foil in a mixed electrolyte solution of glycerin and NH4F and then annealed at 200°C, 400°C, 600°C, and 800°C, respectively. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), water contact angle (WCA), and photoluminescence (PL). It was found that low temperature (below 600°C) has no significant influence on surface morphology, but the diameter of the nanotube increases from 40 to 50 nm with increasing temperature. At 800°C, the nanotube arrays are completely destroyed and only dense rutile film is observed. Samples unannealed and annealed at 200°C are amorphous. At 400°C, anatase phase appears. At 600°C, rutile phase appears. At 800°C, anatase phase changes into rutile phase completely. The wettability of the TN films shows that the WCAs for all samples freshly annealed at different temperatures are about 0°. After the annealed samples have been stored in air for 1 month, the WCAs increase to 130°, 133°, 135°, 141°, and 77°, respectively. Upon ultraviolet (UV) irradiation, they exhibit a significant transition from hydrophobicity to hydrophilicity. Especially, samples unannealed and annealed at 400°C show high photoinduced hydrophilicity. PMID:25426006

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

    NASA Astrophysics Data System (ADS)

    Kim, Jongsu; Park, Hyunkyu; Kang, Bongchul; Ku, Renata; Ham, Chulho; Yang, Minyang

    2011-10-01

    We demonstrate the use of a highly effective biosensor array to fulfill the requirements of high intensity, reduced nonspecific adsorption (NSA), and low sample usage. The mixed self-assembled monolayers (SAMs), consisting of methyl-terminated and methoxy-(polyethylene glycol (PEG))-terminated silanes, were newly applied as the background layer to reduce the background NSA via wettability control. The surface was modified by a plasma process with a pattern mask. Gold nanoparticles (AuNPs) were grafted within pattern-modified regions to increase intensity and were modified with protein G variants with cysteine residues to immobilize the antibody proteins directly. The target protein samples were selectively dewetted by the high throughput wiping process, while retaining semi-contact with the substrate. The data revealed that the background NSA was significantly reduced by 78% with selective dewetting compared to the standard method. Furthermore, the peak intensity was improved 5 times by applying AuNPs as compared to that of a planar surface, and the protein requirement was significantly reduced versus the standard process.

  17. The wettability of carbon/TiB2 composite materials by aluminum in cryolite melts

    NASA Astrophysics Data System (ADS)

    Watson, K. D.; Toguri, J. M.

    1991-10-01

    Both pure TiB2 and carbon/TiB2 composites are potential cathode materials for aluminum reduction cells. An important requirement for this application is that the material be wetted by aluminum in cryolite melts. A sessile drop technique combined with X-ray radiography was used to measure the contact angle formed between aluminum and pure hot-pressed TiB2, carbon/TiB2 composite, graphite, and a carbonaceous cement in cryolite melts. Pure hot-pressed TiB2 was found to be completely wetted by aluminum in cryolite melts. Graphite and the carbonaceous cement were nonwetted by aluminum in cryolite melts, the contact angles being in the range of 144 to 158 deg. The contact angle formed by aluminum on the carbon/TiB2 composite in cryolite melts exhibited time dependency. It was proposed the time dependency was due to (1) removal of contamination from the composite surface and (2) removal of aluminum from the drop. The wettability of the composite material increased as the TiB2 content increased.

  18. Wettability and Swelling Behavior of a Weak Polybasic Brush: Influence of Divalent Salts in the Environment

    E-print Network

    Chen Qu

    2015-11-07

    We have studied the response of surface properties and swelling behaviors of annealed poly(2-vinyl pyridine) (P2VP) brushes covalently tethered to solid planar surfaces to divalent salts in aqueous solutions at varied pH values. Results derived from the quartz crystal microbalance technique, atomic force microscope and contact angle goniometry indicate that annealed polybase brushes undergo conformational transitions upon addition of divalent salts over a wide range of pH values below pKa: at low ionic strength, polybase brushes swell upon salts addition; at high ionic strength, polybase brushes collapse with salts addition. The extent and sensitive range of brushes conformational transition induced by divalent ions are found to be grater and broader than that caused by monovalent ions at similar ionic strength, indicating stronger effects on screening, osmotic pressure and bridging interaction. In addition, wetting measurements indicate that polybase-divalent counterions interactions can be used to switch surface characteristics from hydrophilic to hydrophobic in a predictable manner. The immediate implications of these experimental results are related to design of "smart" surfaces with controllable charge distribution, membrane thickness and wettability.

  19. The August Krogh Institute: Capillaries and beyond.

    PubMed

    Sjøgaard, G

    2015-12-01

    Bengt Saltin knew very well the history and work of the giants whose shoulders he was standing upon, such as August Krogh and Johannes Lindhard. He was basically a physiologist interested in physical activity and exercise, particularly in the cardiovascular and muscular responses. Some of his major original contributions were (a) the human muscle model in terms of the one-legged, knee extensor quantifying work by the high-precision Krogh ergometer and, using this, challenging Krogh's proposed autoregulation of capillary blood flow during exercise; (b) the electrolyte fluxes quantification on an intra- and extra-cellular level in human muscle during exercise to reveal such changes as possible fatigue mechanisms; and (c) the evidence presented that underlined the health-enhancing effect of physical exercise training from bedside to workplace. PMID:26454264

  20. Capillary Liquid Chromatography at Ultrahigh Pressures

    NASA Astrophysics Data System (ADS)

    Jorgenson, James W.

    2010-07-01

    Ultrahigh-pressure liquid chromatography (UHPLC) is a method of liquid chromatography utilizing sub-2-?m particles packed into capillary columns 25 to 100 cm long. Columns of this length packed with particles this fine require operation with pressures from 1,000 to 7,000 bar (15,000 to 100,000 psi). The advantages of this technique are high separation powers (theoretical plate counts from 100,000 to 300,000) and run times from a few minutes (isocratic) to a few hours (long gradients). This review discusses the background and theoretical basis of UHPLC, practical aspects of UHPLC hardware, examples of separations, future areas for research in UHPLC, and techniques that are both competitive with and complementary to UHPLC.