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Sample records for wettability capillary action

  1. Capillary flow solder wettability test

    SciTech Connect

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

    1996-01-01

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

  2. Influence of wettability variations on dynamic effects in capillary pressure

    NASA Astrophysics Data System (ADS)

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

    2010-08-01

    Traditional continuum-based multiphase simulators incorporate a capillary pressure-saturation relationship that assumes instantaneous attainment of equilibrium following a disturbance. This assumption may not be appropriate for systems where the capillary pressure is a function of the rate of change of saturation, a phenomenon referred to as dynamic capillary pressure. Previous studies have investigated the impact of soil and fluid properties on dynamic effects in capillary pressure; however, the impact of wettability on this phenomenon has not been investigated to date. In this study, two-phase multistep outflow (MSO) experiments conducted in chemically treated sands with different equilibrium contact angles were used to investigate the influence of wettability variations on dynamic effects in capillary pressure during displacement of water by tetrachloroethene (PCE). Data from the MSO experiments were modeled with a multiphase flow simulator that includes dynamic effects and were also analyzed through comparisons with theoretical model predictions for interface movement in a single capillary tube. Results showed that a faster approach to equilibrium, characterized by smaller fitted damping coefficients, occurred in sands with larger equilibrium contact angles. Damping coefficients for sands with an operational contact angle greater than 80° were found to be an order of magnitude smaller than those with an operational contact angle less than 65°. These results suggest that it may be possible to neglect dynamic effects in capillary pressure in systems that approach intermediate-wet conditions but that these effects will be increasingly important in more water-wet systems.

  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; Siddhartha Seth; Jason Zhengxin Tong; Peigui Yin; Shaochang Wo

    2006-02-01

    -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

    -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 R. Morrow

    2004-07-01

    -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. 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

    -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.

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

    SciTech Connect

    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

    -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.

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

    SciTech Connect

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

    2005-04-01

    -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.

  9. Directional transport of impinging capillary jet on wettability engineered surfaces

    NASA Astrophysics Data System (ADS)

    Ghosh, Aritra; Chatterjee, Souvick; Sinha Mahapatra, Pallab; Ganguly, Ranjan; Megaridis, Constantine

    2015-11-01

    Impingement of capillary jet on a surface is important for applications like heat transfer, or for liquid manipulation in bio-microfluidic devices. Using wettability engineered surfaces, we demonstrate pump-less and directional transport of capillary jet on a flat surface. Spatial contrast of surface energy and a wedge-shape geometry of the wettability confined track on the substrate facilitate formation of instantaneous spherical bulges upon jet impingement; these bulges are further transported along the superhydrophilic tracks due to Laplace pressure gradient. Critical condition warranted for formation of liquid bulge along the varying width of the superhydrophilic track is calculated analytically and verified experimentally. The work throws light on novel fluid phenomena of unidirectional jet impingement on wettability confined surfaces and provides a platform for innovative liquid manipulation technique for further application. By varying the geometry and wettability contrast on the surface, one can achieve volume flow rates of ~ O(100 μL/sec) and directionally guided transport of the jet liquid, pumplessly at speeds of ~ O(10cm/sec).

  10. Capillary action liquid chromatography.

    PubMed

    Zhang, Bo; Bergström, Edmund T; Goodall, David M; Myers, Peter

    2009-06-01

    Capillary action LC (caLC) is introduced as a technique using capillary action as the driving force to perform LC in capillary columns packed with HPLC type microparticulate materials. A dry packing method with centrifugal force was developed to prepare capillary columns in parallel (10 columns per 3 min) to support their disposable use in caLC. Using a digital microscope for real-time imaging and recording separations of components in a dye mixture, caLC was found to have flow characteristics similar to TLC. Based on the investigation of microparticulate HPLC silica gels of different size (1.5-10 microm) and a typical TLC grade irregular medium, Merck 60G silica, the van Deemter curves suggested molecular diffusion as the major contribution to band broadening in caLC. With Waters Xbridge 2.6 microm silica, plate heights down to 8.8 microm were obtained, comparable to those achievable in HPLC. Assisted by an image-processing method, the visual caLC separation was converted to a classical chromatogram for further data analysis and such a facility confirmed the observation of highly efficient bands.

  11. 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.

  12. Silicon ribbon growth by a capillary action shaping technique

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  13. 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.

  14. 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.

  15. 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 ( θCRM; liquid penetration into a 3-d system), the Wilhelmy plate method ( θWPM; measurement of capillary forces acting on a plane sample) and the Sessile Drop Method ( θSDM; optical CA analysis of drop contour on a plane sample). Results were compared with the CAs calculated from capillary rise in long vertical columns ( θECR), 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 ( θEWPM), as well as the Sessile Drop CA, θSDM, were close to the ones of θECR. We concluded that θEWPM and θSDM 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.

  16. Effects of fractional wettability on capillary pressure saturation relative permeability relations of two-fluid systems

    NASA Astrophysics Data System (ADS)

    Hwang, Sang Il; Lee, Kwang Pyo; Lee, Dong Soo; Powers, Susan E.

    2006-02-01

    Capillary pressure ( Pc)-saturation ( S)-relative permeability ( kr) relationships must be quantified to accurately predict non-aqueous phase liquid (NAPL) distribution in the subsurface. Several experimental techniques are presented here for two-fluid Pc- S- kr relationships for various saturation paths to better define the effect of fractional wettability on these relationships. During the primary drainage path of the Pc- S curves, the air-water system showed no distinct trend as a function of the fraction of sand treated by organosilane (S) to render it non-water wetting. In a NAPL-water system, however, a consistent decrease of capillary pressure with increase of the fraction of non-water wetting sands was observed. The much lower contact angle for air-water (a-w) system may result in the observed insensitivity of the a-w Pc- S curves to fractional wettability, at least for the PD pathway. For the main imbibition path of NAPL-water system, capillary pressure decreased as the fraction of the S component increased, requiring forced imbibition (negative capillary pressures) for a certain range of saturations. Systems with an increasing percentage of the S component also exhibited a higher water kr and lower NAPL or air kr at a given saturation for the primary drainage and main imbibition paths in both air-water and NAPL-water systems. The increase of water kr with increase of the fraction of the S component can be explained by the ability of water to occupy larger and highly conductive pores in such a system. Experimental kr- S data for the primary drainage path of NAPL-water system presented here were used to test the Bradford et al. [Bradford SA, Abriola LM, Leij FJ. Wettability effects on two- and three-fluid relative permeabilities. J Contam Hydrol 1997;28:171-91] model and the modified Mualem model for estimating the kr- S curves from measured Pc- S data as a function of fractional wettability. Both models predicted significantly less variation in the kr- S

  17. 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.

  18. 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 θc which is related to the pore geometry by the equation ctg( θc) = πd2, 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 μm 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.

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

    PubMed

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

    2012-12-11

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

  20. 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 (˜μL) 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.

  1. Immunogold-silver staining by capillary action.

    PubMed

    Kumar, R K; Braye, S G; Crouch, R L

    1989-12-01

    The authors have developed an improved method for immunogold-silver staining of paraffin sections. Using a manual capillary action staining system, they were able to simplify the technical aspects of the procedure, permitting rapid processing of large batches of slides with better reproducibility. Background staining was decreased by use of buffers containing a detergent. The use of a light-stable silver reagent permitted greater control of the enhancement stage. The method yielded a high degree of contrast with negligible nonspecific staining. Sensitivity was comparable to that obtained with conventional enzymatic immunostaining. However, the authors noted that trypsinization of sections was rendered unnecessary for those antigens for which such pretreatment was usually required, and the need for special fixatives could be eliminated. The method was also applicable to immunostaining of frozen sections. Immunogold-silver staining by capillary action deserves consideration as an alternative to existing immunohistochemical methods in diagnostic histopathology.

  2. 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.

  3. Wettability effect on capillary trapping of supercritical CO2 at pore-scale: micromodel experiment and numerical modeling

    NASA Astrophysics Data System (ADS)

    Hu, R.; Wan, J.

    2015-12-01

    Wettability of reservoir minerals along pore surfaces plays a controlling role in capillary trapping of supercritical (sc) CO2 in geologic carbon sequestration. The mechanisms controlling scCO2 residual trapping are still not fully understood. We studied the effect of pore surface wettability on CO2 residual saturation at the pore-scale using engineered high pressure and high temperature micromodel (transparent pore networks) experiments and numerical modeling. Through chemical treatment of the micromodel pore surfaces, water-wet, intermediate-wet, and CO2-wet micromodels can be obtained. Both drainage and imbibition experiments were conducted at 8.5 MPa and 45 °C with controlled flow rate. Dynamic images of fluid-fluid displacement processes were recorded using a microscope with a CCD camera. Residual saturations were determined by analysis of late stage imbibition images of flow path structures. We performed direct numerical simulations of the full Navier-Stokes equations using a volume-of-fluid based finite-volume framework for the primary drainage and the followed imbibition for the micromodel experiments with different contact angles. The numerical simulations agreed well with our experimental observations. We found that more scCO2 can be trapped within the CO2-wet micromodel whereas lower residual scCO2 saturation occurred within the water-wet micromodels in both our experiments and the numerical simulations. These results provide direct and consistent evidence of the effect of wettability, and have important implications for scCO2 trapping in geologic carbon sequestration.

  4. 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 τ(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

  5. 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.

  6. Complete one-hour immunocytochemistry based on capillary action.

    PubMed

    Reed, J A; Manahan, L J; Park, C S; Brigati, D J

    1992-09-01

    We describe a less than one-hour manual method for immunocytochemical analyses of B5 or formalin-fixed, paraffin-embedded tissue sections. The method employs capillary action to sequentially apply, incubate and remove liquid reagents from apposed pairs of up to 20 glass microscope slides and allows for simultaneous immunocytochemical analyses of as many as 10 different antigens. The method described here uses a) positively charged glass slides to rapidly immobilize tissue sections; b) rapid deparaffinization techniques; c) multipurpose reagents; d) ethanol-enriched buffer washes to improve capillary action and reduce nonspecific background; e) a single broad spectrum streptavidin-peroxidase or streptavidin-alkaline phosphatase detection system that identifies most primary monoclonal and polyclonal antibodies; and f) specific immunocytochemical signal amplification by cyclic chromogen enhancement.

  7. 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%.

  8. Predicting reservoir wettability via well logs

    NASA Astrophysics Data System (ADS)

    Feng, Cheng; Fu, Jinhua; Shi, Yujiang; Li, Gaoren; Mao, Zhiqiang

    2016-06-01

    Wettability is an important factor in controlling the distribution of oil and water. However, its evaluation has so far been a difficult problem because no log data can directly indicate it. In this paper, a new method is proposed for quantitatively predicting reservoir wettability via well log analysis. Specifically, based on the J function, diagenetic facies classification and the piecewise power functions, capillary pressure curves are constructed from conventional logs and a nuclear magnetic resonance (NMR) log respectively. Under the influence of wettability, the latter is distorted while the former remains unaffected. Therefore, the ratio of the median radius obtained from the two kinds of capillary pressure curve is calculated to reflect wettability, a quantitative relationship between the ratio and reservoir wettability is then established. According to the low-permeability core sample capillary pressure curve, NMR {{T}2} spectrum and contact angle experimental data from the bottom of the Upper Triassic reservoirs in western Ordos Basin, China, two kinds of constructing capillary pressure curve models and a predictive wettability model are calibrated. The wettability model is verified through the Amott wettability index and saturation exponent from resistivity measurement and their determined wettability levels are comparable, indicating that the proposed model is quite reliable. In addition, the model’s good application effect is exhibited in the field study. Thus, the quantitatively predicting reservoir wettability model proposed in this paper provides an effective tool for formation evaluation, field development and the improvement of oil recovery.

  9. Capillary action in a crack on the surface of asteroids with an application to 433 Eros

    NASA Astrophysics Data System (ADS)

    Jiang, Yu; Baoyin, Hexi

    2016-08-01

    Some asteroids contain water ice, and a space mission landing on an asteroid may take liquid to the surface of the asteroid. Gas pressure is very weak on the surface of asteroids. Here we consider the capillary action in a crack on the surface of irregular asteroids. The crack is modeled as a capillary which has a fixed radius. An asteroid's irregular gravitational potential influences the height of the liquid in the capillary. The height of the liquid in the capillary on the surface of such asteroids is derived from the asteroid's irregular gravitational potential. Capillary mechanisms are expected to produce an inhomogeneaous distribution of emergent liquid on the surface. This result is applied to asteroid 433 Eros, which has an irregular, elongated, and concave shape. Two cases are considered: (1) we calculate the height of the liquid in the capillary when the direction of the capillary is perpendicular to the local surface of the asteroid; (2) we calculate the height of the liquid in the capillary when the direction of the capillary is parallel to the vector from the center of mass to the surface position. The projected height in the capillary on the local surface of the asteroid seems to depend on the assumed direction of the capillary.

  10. 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.

  11. Size-specific concentration of DNA to a nanostructured tip using dielectrophoresis and capillary action.

    PubMed

    Yeo, Woon-Hong; Chung, Jae-Hyun; Liu, Yaling; Lee, Kyong-Hoon

    2009-08-01

    One of the critical challenges in the fields of disease diagnostics and environmental monitoring is to concentrate extracellular DNA from a sample mixture rapidly. Unlike genomic DNA in normal cells, extracellular DNA dissolved in a biological sample can potentially offer crucial information about pathogens and toxins. The current concentration methods, however, are not able to directly concentrate extracellular DNA due to aggressive sample preparation steps. This paper presents a concentration mechanism of extracellular DNA onto a nanostructured tip using dielectrophoresis (DEP) in conjunction with capillary action. DNA immersed in a solution is captured onto a nanotip by two sequential actions: (1) attraction of DNA and other bioparticles in the vicinity of a nanotip by DEP and (2) size-specific capture of DNA onto the nanotip by capillary action. To investigate the size-specific capturing mechanism, an analytical model for the capillary action on a nanotip is presented, which is compared to the experiment for capturing polystyrene nanospheres. This analysis predicts the capture of a spherical particle smaller than 0.39 times a nanotip diameter, whereas our experiment shows that polystyrene spheres smaller than 0.84 times a nanotip diameter are captured. This discrepancy can be caused by the increase of the capturing force due to attractive DEP force. In addition, the diameter of the captured spheres can be increased by other experimental conditions including the tip geometry, the multiple particle interaction, and the contact angles. When a nanotip is used for concentrating lambda-DNA, 6.7 pg/mL (210 aM) of DNA is selectively extracted from a sample mixture containing lambda-DNA and Drosophila cells in one minute. The captured DNA is investigated by fluorescence microscopy, scanning electron microscopy (SEM), and X-ray analysis. This nanotip-based DNA concentrating method is a rapid and highly sensitive technique to detect extracellular DNA from a sample mixture.

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

    PubMed

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

    2013-08-14

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

  13. Optical fiber nanoprobe preparation for near-field optical microscopy by chemical etching under surface tension and capillary action.

    PubMed

    Mondal, Samir K; Mitra, Anupam; Singh, Nahar; Sarkar, S N; Kapur, Pawan

    2009-10-26

    We propose a technique of chemical etching for fabrication of near perfect optical fiber nanoprobe (NNP). It uses photosensitive single mode optical fiber to etch in hydro fluoric (HF) acid solution. The difference in etching rate for cladding and photosensitive core in HF acid solution creates capillary ring along core-cladding boundary under a given condition. The capillary ring is filled with acid solution due to surface tension and capillary action. Finally it creates near perfect symmetric tip at the apex of the fiber as the height of the acid level in capillary ring decreases while width of the ring increases with continuous etching. Typical tip features are short taper length (approximately 4 microm), large cone angle (approximately 38 degrees ), and small probe tip dimension (<100 nm). A finite difference time domain (FDTD) analysis is also presented to compare near field optics of the NNP with conventional nanoprobe (CNP). The probe may be ideal for near field optical imaging and sensor applications.

  14. Automatic sampling and analysis of organics and biomolecules by capillary action-supported contactless atmospheric pressure ionization mass spectrometry.

    PubMed

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

    2013-01-01

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

  15. Automatic sampling and analysis of organics and biomolecules by capillary action-supported contactless atmospheric pressure ionization mass spectrometry.

    PubMed

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

    2013-01-01

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

  16. Wettability contrasts between fresh and weathered diesel fuels

    NASA Astrophysics Data System (ADS)

    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.

  17. Planar lens integrated capillary action microfluidic immunoassay device for the optical detection of troponin I.

    PubMed

    Mohammed, Mazher-Iqbal; Desmulliez, Marc P Y

    2013-01-01

    Optical based analysis in microfluidic and lab-on-a-chip systems are currently considered the gold standard methodology for the determination of end point reactions for various chemical and biological reaction processes. Typically, assays are performed using bulky ancillary apparatus such as microscopes and complex optical excitation and detection systems. Such instrumentation negates many of the advantages offered by device miniaturisation, particularly with respect to overall portability. In this article, we present a CO2 laser ablation technique for rapidly prototyping on-chip planar lenses, in conjunction with capillary action based autonomous microfluidics, to create a miniaturised and fully integrated optical biosensing platform. The presented self-aligned on-chip optical components offer an efficient means to direct excitation light within microfluidics and to directly couple light from a LED source. The device has been used in conjunction with a miniaturised and bespoke fluorescence detection platform to create a complete, palm sized system (≈60 × 80 × 60 mm) capable of performing fluoro-immunoassays. The system has been applied to the detection of cardiac Troponin I, one of the gold standard biomarkers for the diagnosis of acute myocardial infarction, achieving a lower detection limit of 0.08 ng/ml, which is at the threshold of clinically applicable concentrations. The portable nature of the complete system and the biomarker detection capabilities demonstrate the potential of the devised instrumentation for use as a medical diagnostics device at the point of care.

  18. Exploration of the action pattern of Streptomyces hyaluronate lyase using high-resolution capillary electrophoresis.

    PubMed

    Park, Y; Cho, S; Linhardt, R J

    1997-02-01

    Hyaluronic acid was treated exhaustively with a hyaluronate lyase (hyaluronidase, EC 4.2.2.1) from Streptomyces hyalurolyticus to obtain a tetrasaccharide and a hexasaccharide product in a molar ratio of 1 to 1.2. The tetrasaccharide product was fluorescently labeled at the reducing end by reductive amination with 7-amino 1,3-naphthalene disulfonic acid (AGA) and the structure of the conjugate was determined spectroscopically. Partial treatments of hyaluronic acid with hyaluronate lyase afforded complex mixtures of oligosaccharides that were similarly fluorescently labeled. These labeled oligosaccharide mixtures were analyzed using high-resolution capillary electrophoresis. The resulting electropherograms showed the content of each hyaluronic acid derived oligosaccharide, having a degree of polymerization (dp) from 4 to 50, throughout the enzymatic reaction. Computer simulation studies gave comparable kinetic profiles suggesting that hyaluronate lyase exhibits a random endolytic action pattern. Interestingly, oligosaccharides of certain size (dp) were under-represented in these oligosaccharide mixtures suggesting that linkages at spacings of 10 to 12 saccharide units are somewhat resistant to this enzyme. The cause of this resistance might be the result of secondary or higher order structural features present in the hyaluronic acid polymer.

  19. Planar lens integrated capillary action microfluidic immunoassay device for the optical detection of troponin I

    PubMed Central

    Mohammed, Mazher-Iqbal; Desmulliez, Marc P. Y.

    2013-01-01

    Optical based analysis in microfluidic and lab-on-a-chip systems are currently considered the gold standard methodology for the determination of end point reactions for various chemical and biological reaction processes. Typically, assays are performed using bulky ancillary apparatus such as microscopes and complex optical excitation and detection systems. Such instrumentation negates many of the advantages offered by device miniaturisation, particularly with respect to overall portability. In this article, we present a CO2 laser ablation technique for rapidly prototyping on-chip planar lenses, in conjunction with capillary action based autonomous microfluidics, to create a miniaturised and fully integrated optical biosensing platform. The presented self-aligned on-chip optical components offer an efficient means to direct excitation light within microfluidics and to directly couple light from a LED source. The device has been used in conjunction with a miniaturised and bespoke fluorescence detection platform to create a complete, palm sized system (≈60 × 80 × 60 mm) capable of performing fluoro-immunoassays. The system has been applied to the detection of cardiac Troponin I, one of the gold standard biomarkers for the diagnosis of acute myocardial infarction, achieving a lower detection limit of 0.08 ng/ml, which is at the threshold of clinically applicable concentrations. The portable nature of the complete system and the biomarker detection capabilities demonstrate the potential of the devised instrumentation for use as a medical diagnostics device at the point of care. PMID:24396546

  20. Altering Emulsion Stability with Heterogeneous Surface Wettability

    PubMed Central

    Meng, Qiang; Zhang, Yali; Li, Jiang; Lammertink, Rob G. H.; Chen, Haosheng; Tsai, Peichun Amy

    2016-01-01

    Emulsions–liquid droplets dispersed in another immiscible liquid–are widely used in a broad spectrum of applications, including food, personal care, agrochemical, and pharmaceutical products. Emulsions are also commonly present in natural crude oil, hampering the production and quality of petroleum fuels. The stability of emulsions plays a crucial role in their applications, but controlling the stability without external driving forces has been proven to be difficult. Here we show how heterogeneous surface wettability can alter the stability and dynamics of oil-in-water emulsions, generated by a co-flow microfluidic device. We designed a useful methodology that can modify a micro-capillary of desired heterogeneous wettability (e.g., alternating hydrophilic and hydrophobic regions) without changing the hydraulic diameter. We subsequently investigated the effects of flow rates and heterogeneous wettability on the emulsion morphology and motion. The experimental data revealed a universal critical timescale of advective emulsions, above which the microfluidic emulsions remain stable and intact, whereas below they become adhesive or inverse. A simple theoretical model based on a force balance can be used to explain this critical transition of emulsion dynamics, depending on the droplet size and the Capillary number–the ratio of viscous to surface effects. These results give insight into how to control the stability and dynamics of emulsions in microfluidics with flow velocity and different wettability. PMID:27256703

  1. Altering Emulsion Stability with Heterogeneous Surface Wettability

    NASA Astrophysics Data System (ADS)

    Meng, Qiang; Zhang, Yali; Li, Jiang; Lammertink, Rob G. H.; Chen, Haosheng; Tsai, Peichun Amy

    2016-06-01

    Emulsions–liquid droplets dispersed in another immiscible liquid–are widely used in a broad spectrum of applications, including food, personal care, agrochemical, and pharmaceutical products. Emulsions are also commonly present in natural crude oil, hampering the production and quality of petroleum fuels. The stability of emulsions plays a crucial role in their applications, but controlling the stability without external driving forces has been proven to be difficult. Here we show how heterogeneous surface wettability can alter the stability and dynamics of oil-in-water emulsions, generated by a co-flow microfluidic device. We designed a useful methodology that can modify a micro-capillary of desired heterogeneous wettability (e.g., alternating hydrophilic and hydrophobic regions) without changing the hydraulic diameter. We subsequently investigated the effects of flow rates and heterogeneous wettability on the emulsion morphology and motion. The experimental data revealed a universal critical timescale of advective emulsions, above which the microfluidic emulsions remain stable and intact, whereas below they become adhesive or inverse. A simple theoretical model based on a force balance can be used to explain this critical transition of emulsion dynamics, depending on the droplet size and the Capillary number–the ratio of viscous to surface effects. These results give insight into how to control the stability and dynamics of emulsions in microfluidics with flow velocity and different wettability.

  2. Altering Emulsion Stability with Heterogeneous Surface Wettability.

    PubMed

    Meng, Qiang; Zhang, Yali; Li, Jiang; Lammertink, Rob G H; Chen, Haosheng; Tsai, Peichun Amy

    2016-01-01

    Emulsions-liquid droplets dispersed in another immiscible liquid-are widely used in a broad spectrum of applications, including food, personal care, agrochemical, and pharmaceutical products. Emulsions are also commonly present in natural crude oil, hampering the production and quality of petroleum fuels. The stability of emulsions plays a crucial role in their applications, but controlling the stability without external driving forces has been proven to be difficult. Here we show how heterogeneous surface wettability can alter the stability and dynamics of oil-in-water emulsions, generated by a co-flow microfluidic device. We designed a useful methodology that can modify a micro-capillary of desired heterogeneous wettability (e.g., alternating hydrophilic and hydrophobic regions) without changing the hydraulic diameter. We subsequently investigated the effects of flow rates and heterogeneous wettability on the emulsion morphology and motion. The experimental data revealed a universal critical timescale of advective emulsions, above which the microfluidic emulsions remain stable and intact, whereas below they become adhesive or inverse. A simple theoretical model based on a force balance can be used to explain this critical transition of emulsion dynamics, depending on the droplet size and the Capillary number-the ratio of viscous to surface effects. These results give insight into how to control the stability and dynamics of emulsions in microfluidics with flow velocity and different wettability. PMID:27256703

  3. Capillary action-supported contactless atmospheric pressure ionization for the combined sampling and mass spectrometric analysis of biomolecules.

    PubMed

    Hsieh, Cheng-Huan; Chang, Chia-Hsien; Urban, Pawel L; Chen, Yu-Chie

    2011-04-15

    It is proposed that a short tapered capillary can be utilized as a nanoliter-volume sampling tool and sample emitter for generation of gas-phase ions in front of the mass spectrometer, without the need for using an additional electric power supply, a gas supply, or a syringe pump. A wide range of molecules can be analyzed in pure solutions and complex matrixes (cell extract, urine, and plant tissue) with no or minimum sample preparation. Singly and multiply charged ions can be detected in either positive or negative-ion mode. Because of the nanoliter-volume sampling and low spectral background, the mass detection limit for bradykinin is in the low attomole range. Other advantages include simplicity, disposability, and low cost. The putative mechanism of the ion formation in this capillary-action supported contactless spray emitter is discussed.

  4. 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.

  5. On wettability of shale rocks.

    PubMed

    Roshan, H; Al-Yaseri, A Z; Sarmadivaleh, M; Iglauer, S

    2016-08-01

    The low recovery of hydraulic fracturing fluid in unconventional shale reservoirs has been in the centre of attention from both technical and environmental perspectives in the last decade. One explanation for the loss of hydraulic fracturing fluid is fluid uptake by the shale matrix; where capillarity is the dominant process controlling this uptake. Detailed understanding of the rock wettability is thus an essential step in analysis of loss of the hydraulic fracturing fluid in shale reservoirs, especially at reservoir conditions. We therefore performed a suit of contact angle measurements on a shale sample with oil and aqueous ionic solutions, and tested the influence of different ion types (NaCl, KCl, MgCl2, CaCl2), concentrations (0.1, 0.5 and 1M), pressures (0.1, 10 and 20MPa) and temperatures (35 and 70°C). Furthermore, a physical model was developed based on the diffuse double layer theory to provide a framework for the observed experimental data. Our results show that the water contact angle for bivalent ions is larger than for monovalent ions; and that the contact angle (of both oil and different aqueous ionic solutions) increases with increase in pressure and/or temperature; these increases are more pronounced at higher ionic concentrations. Finally, the developed model correctly predicted the influence of each tested variable on contact angle. Knowing contact angle and therefore wettability, the contribution of the capillary process in terms of water uptake into shale rocks and the possible impairment of hydrocarbon production due to such uptake can be quantified.

  6. On wettability of shale rocks.

    PubMed

    Roshan, H; Al-Yaseri, A Z; Sarmadivaleh, M; Iglauer, S

    2016-08-01

    The low recovery of hydraulic fracturing fluid in unconventional shale reservoirs has been in the centre of attention from both technical and environmental perspectives in the last decade. One explanation for the loss of hydraulic fracturing fluid is fluid uptake by the shale matrix; where capillarity is the dominant process controlling this uptake. Detailed understanding of the rock wettability is thus an essential step in analysis of loss of the hydraulic fracturing fluid in shale reservoirs, especially at reservoir conditions. We therefore performed a suit of contact angle measurements on a shale sample with oil and aqueous ionic solutions, and tested the influence of different ion types (NaCl, KCl, MgCl2, CaCl2), concentrations (0.1, 0.5 and 1M), pressures (0.1, 10 and 20MPa) and temperatures (35 and 70°C). Furthermore, a physical model was developed based on the diffuse double layer theory to provide a framework for the observed experimental data. Our results show that the water contact angle for bivalent ions is larger than for monovalent ions; and that the contact angle (of both oil and different aqueous ionic solutions) increases with increase in pressure and/or temperature; these increases are more pronounced at higher ionic concentrations. Finally, the developed model correctly predicted the influence of each tested variable on contact angle. Knowing contact angle and therefore wettability, the contribution of the capillary process in terms of water uptake into shale rocks and the possible impairment of hydrocarbon production due to such uptake can be quantified. PMID:27156090

  7. 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

  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.

  9. Direct detection of underivatized chitooligosaccharides produced through chitinase action using capillary zone electrophoresis.

    PubMed

    Blanes, Lucas; Saito, Renata M; Genta, Fernando A; Donegá, Juliana; Terra, Walter R; Ferreira, Clélia; do Lago, Claudimir Lucio

    2008-02-01

    Capillary electrophoresis with capacitively coupled contactless conductivity detection was successfully used to quantify N-acetylglucosamine and five N-acetyl-chitooligosaccharides (C2-C6) produced after reaction with a purified chitinase (TmChi) from Tenebrio molitor (Coleoptera). No derivatization process was necessary. The separation was developed using 10 mM NaOH with 10% (v/v) acetonitrile as background electrolyte and homemade equipment with a system that avoids the harmful effect of electrolysis. The limit of detection for all oligosaccharides was ca. 3microM, and the results indicated that the larger the oligosaccharide, the higher the sensitivity. Analysis of the chitooligosaccharides produced revealed that TmChi has an endolytic cleavage pattern with C5 as the best substrate (higher catalytic efficiency kcat/KM) releasing C2 and C3.

  10. Wettability of a Single Carbon Fiber.

    PubMed

    Qiu, Si; Fuentes, Carlos A; Zhang, Dongxing; Van Vuure, Aart Willem; Seveno, David

    2016-09-27

    Wettability as determined from contact angle measurements is a suitable parameter for characterizing the physical bonding of a polymer matrix and reinforcing fibers, but it is very challenging to measure the capillary force exerted by a probe liquid on a fiber accurately for very fine fibers such as single carbon fibers. Herein, we propose an innovative method for measuring dynamic contact angles with a tensiometer, considering both the intrinsic variability of the carbon fiber diameter and the extremely small amplitude of the capillary forces, allowing the measurement of reliable dynamic contact angles over a large range of contact line velocities. The analysis of the contact angle dynamics by the molecular-kinetic theory permits us to check the relevancy of the measured contact angles and to obtain the static contact angle value, improving the prospect of employing tensiometry to better understand the wetting behavior of carbon fibers.

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

    PubMed

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

    2011-09-13

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

  12. The Wettability of Shale by CO2 and Its Impact on Geologic CO2 Sequestration

    NASA Astrophysics Data System (ADS)

    Guiltinan, E. J.; Cardenas, M. B.; Espinoza, D. N.; Yoon, H.; Dewers, T. A.

    2015-12-01

    The geologic sequestration of CO2 is widely considered as a potential solution for decreasing anthropogenic atmospheric CO2 emissions. Wettability of fluids within reservoir materials is a critical factor in determining the efficiency of structural and residual trapping, two major mechanisms of geologic sequestration. Individual reservoir minerals are often targeted for wettability studies. Current practice applies these results, recorded under laboratory conditions, to in-situ reservoir rock; however the wide variety of measured contact angles reported in the literature calls this practice into question. To address these issues and to study the wettability of shale caprock, resedimentation techniques are employed. These techniques allow for the creation of synthetic shales with controlled, homogeneous mineralogies. In addition, the systematic variation of the mineralogy allows for the characterization of shale wettability as a function of mineralogical composition. A novel design has been developed and used to conduct wettability experiments at reservoir conditions using high resolution X-ray computer tomography. Using this technique the wettability of resedimented shales and natural shales are compared at different reservoir conditions. Next, Lattice Boltzmann modelling methods are used to simulate capillary entry pressure into a shale capillary. Adhesion parameters along the wall are tuned to the results of the synthetic shales and heterogeneity is incorporated to estimate the capillary entry pressure into a natural shale. Understanding the mineralogical components of shale wetting allows for the prediction of capillary entry pressure based on shale mineralogy which can be used to help select secure CO2 storage sites.

  13. Hydraulic Property Alterations due to Wettability Induced Changes by Diesel Fuels

    NASA Astrophysics Data System (ADS)

    O'Carroll, Denis

    2013-04-01

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

  14. Capillary Hemangioma

    MedlinePlus

    ... Why do capillary hemangiomas on the eyelids cause vision problems? Capillary Hemangiomas of the eyelid can cause ... a capillary hemangioma in the eye socket cause vision problems? A capillary hemangioma in the eye socket ( ...

  15. 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.

  16. Experimental investigations of the wettability of clays and shales

    NASA Astrophysics Data System (ADS)

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

    2009-07-01

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

  17. 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

  18. Wettability Control on Fluid-Fluid Displacements in Patterned Microfluidics

    NASA Astrophysics Data System (ADS)

    Zhao, B.; Trojer, M.; Cueto-Felgueroso, L.; Juanes, R.

    2014-12-01

    Two-phase flow in porous media is important in many natural and industrial processes like geologic CO2 sequestration, enhanced oil recovery, and water infiltration in soil. While it is well known that the wetting properties of porous media can vary drastically depending on the type of media and the pore fluids, the effect of wettability on fluid displacement continues to challenge our microscopic and macroscopic descriptions. Here we study this problem experimentally, starting with the classic experiment of two-phase flow in a capillary tube. We image the shape of the meniscus and measure the associated capillary pressure for a wide range of capillary numbers. We confirm that wettability exerts a fundamental control on meniscus deformation, and synthesize new observations on the dependence of the dynamic capillary pressure on wetting properties (contact angle) and flow conditions (viscosity contrast and capillary number). We compare our experiments to a macroscopic phase-field model of two-phase flow. We use the insights gained from the capillary tube experiments to explore the viscous fingering instability in the Hele-Shaw geometry in the partial-wetting regime. A key difference between a Hele-Shaw cell and a porous medium is the existence of micro-structures (i.e. pores and pore throats). To investigate how these micro-structrues impact fluid-fluid displacement, we conduct experiments on a planar microfluidic device patterned with vertical posts. We track the evolution of the fluid-fluid interface and elucidate the impact of wetting on the cooperative nature of fluid displacement during pore invasion events. We use the insights gained from the capillary tube and patterned microfluidics experiments to elucidate the effect of wetting properties on viscous fingering and capillary fingering in a Hele-Shaw cell filled with glass beads, where we observe a contact-angle-dependent stabilizing behavior for the emerging flow instabilities, as the system transitions from

  19. Enhancing dropwise condensation through bioinspired wettability patterning.

    PubMed

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

    2014-11-01

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

  20. In situ wettability determination improves formation evalution

    SciTech Connect

    Desbrandes, R. )

    1989-08-01

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

  1. Enhancing dropwise condensation through bioinspired wettability patterning.

    PubMed

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

    2014-11-01

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

  2. Capillary sample

    MedlinePlus

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

  3. 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

    2015-09-11

    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 (Π) 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.

  4. 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 (Π) 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

  5. 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 (Π) 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

  6. 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.

  7. Study of a through-silicon/substrate via filling method based on the combinative effect of capillary action and liquid bridge rupture

    NASA Astrophysics Data System (ADS)

    Gu, Jiebin; Liu, Bingjie; Chen, Gaoli; Li, Xinxin

    2016-07-01

    Through-silicon via (TSV) is increasing its importance in advanced device packaging. In this paper, a through-silicon/substrate via filling method based on the combinative effect of liquid bridge rupture and capillary action is proposed and demonstrated. The proposed method is able to achieve alloy vias from the surface of a molten alloy pool. Two different processes were tested in experiments and the results show that one of these processes is able to achieve fully filled vias. In addition, a piece of equipment was specially made for the proposed via filling method. The via filling method studied in this paper has a potential application for TSVs in MEMS packaging.

  8. Antibacterial activity and mode of action of the Artemisia capillaris essential oil and its constituents against respiratory tract infection-causing pathogens.

    PubMed

    Yang, Chang; Hu, Dong-Hui; Feng, Yan

    2015-04-01

    the antibacterial action of A. capillaris essential oil may be mediated through the leakage of these two important ions. In conclusion, A. capillaris essential oil exhibits potent antibacterial activity by inducing morphological changes and leakage of ions in S. aureus bacterial cultures.

  9. Antibacterial activity and mode of action of the Artemisia capillaris essential oil and its constituents against respiratory tract infection-causing pathogens.

    PubMed

    Yang, Chang; Hu, Dong-Hui; Feng, Yan

    2015-04-01

    the antibacterial action of A. capillaris essential oil may be mediated through the leakage of these two important ions. In conclusion, A. capillaris essential oil exhibits potent antibacterial activity by inducing morphological changes and leakage of ions in S. aureus bacterial cultures. PMID:25522803

  10. Effects of surface wettability on gecko adhesion underwater.

    PubMed

    Peng, Z L; Wang, C; Chen, S H

    2014-10-01

    Recent experiments have shown that gecko adhesion underwater depends significantly on surface wettability. Theoretical models of a gecko seta adhering on different substrates are firstly established in order to disclose such an adhesion mechanism. The results show that the capillary force induced by nano-bubbles between gecko seta and the substrate is the mainly influencing factor. The capillary force exhibits an attractive feature between gecko setae and hydrophobic surfaces underwater. However, it is extremely weak or even repulsive on hydrophilic surfaces underwater. A self-similarly splitting model is further considered to simulate multiple gecko setae on substrates underwater. It is interesting to find that the total capillary force depends significantly on the number of nano-bubble bridges and wettability of substrates. The total force is attractive and increases monotonically with the increase of the splitting number on hydrophobic substrates underwater. However, it decreases drastically or even becomes repulsive on hydrophilic substrates underwater. The present result can not only give a reasonable explanation on the existing experimental observations but also be helpful for the design of novel biomimetic adhesives.

  11. Wettability effects on two- and three-fluid relative permeabilities

    NASA Astrophysics Data System (ADS)

    Bradford, Scott A.; Abriola, Linda M.; Leij, Feike J.

    1997-10-01

    Specification of relative permeability ( kr)-saturation ( S) relations for all fluid phases is required for the simulation of multiphase flow and transport in porous media. Indirect methods are frequently employed to estimate these kr- S relations owing to the time, expense, and difficulty associated with direct measurements. A common indirect approach uses capillary pressure data in conjunction with a selected pore-size distribution model to estimate kr- S relations. Such methods typically assume perfect wettability of the solid. Natural porous media, however, are composed of a variety of mineral constituents with different adsorptive properties, which can exhibit non-zero contact angles and/or fractional wettability. Consequently, fluid distributions in natural media may be more complex than those predicted by simple pore-size distribution models and, under such conditions, current estimation approaches for kr may be inadequate. In this work, the pore-size distribution model of N.T. Burdine (1953, Relative permeability calculations from pore-size distribution data. Transactions of the American Institute of Mining, Metallurgical and Petroleum Engineers 198, 71-77) is extended to incorporate wettability variations. In this model, wetting and less wetting (non-wetting or intermediate) fluid pore classes are used to calculate kr for water or organic. The wettability of the porous medium is used to determine the contributions of the pore classes to kr. For both two- and three-fluid systems, the model predicts that an increase in the contact angle (measured through water) or organic-wet fraction of a medium will be accompanied by an increase in the water kr and a decrease in the organic kr. In three-fluid media, kr values for water and organic depend on both liquid saturations when the solid is imperfectly wetted. The model assumes that wettability variation has no influence on the air kr. Model predictions are shown to be consistent with available experimental data.

  12. Wettability of partially suspended graphene

    PubMed Central

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-01-01

    The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle. PMID:27072195

  13. Wettability of partially suspended graphene

    DOE PAGES

    Ondarçuhu, Thierry; Thomas, Vincent; Nuñez, Marc; Dujardin, Erik; Rahman, Atikur; Black, Charles T.; Checco, Antonio

    2016-04-13

    Dependence on the wettability of graphene on the nature of the underlying substrate remains only partially understood. We systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Moreover, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquidmore » interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.« less

  14. 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.

  15. 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

  16. Drop impact and wettability: From hydrophilic to superhydrophobic surfaces

    NASA Astrophysics Data System (ADS)

    Antonini, Carlo; Amirfazli, Alidad; Marengo, Marco

    2012-10-01

    Experiments to understand the effect of surface wettability on impact characteristics of water drops onto solid dry surfaces were conducted. Various surfaces were used to cover a wide range of contact angles (advancing contact angle from 48° to 166°, and contact angle hysteresis from 5° to 56°). Several different impact conditions were analyzed (12 impact velocities on 9 different surfaces, among which 2 were superhydrophobic). Results from impact tests with millimetric drops show that two different regimes can be identified: a moderate Weber number regime (30 < We < 200), in which wettability affects both drop maximum spreading and spreading characteristic time; and a high Weber number regime (We > 200), in which wettability effect is secondary, because capillary forces are overcome by inertial effects. In particular, results show the role of advancing contact angle and contact angle hysteresis as fundamental wetting parameters to allow understanding of different phases of drop spreading and beginning of recoiling. It is also shown that drop spreading on hydrophilic and superhydrophobic surfaces occurs with different time scales. Finally, if the surface is superhydrophobic, eventual impalement, i.e., transition from Cassie to Wenzel wetting state, which might occur in the vicinity of the drop impact area, does not influence drop maximum spreading.

  17. Enhanced condensation heat transfer with wettability patterning

    NASA Astrophysics Data System (ADS)

    Sinha Mahapatra, Pallab; Ghosh, Aritra; Ganguly, Ranjan; Megaridis, Constantine

    2015-11-01

    Condensation of water vapor on metal surfaces is useful for many engineering applications. A facile and scalable method is proposed for removing condensate from a vertical plate during dropwise condensation (DWC) in the presence of non-condensable gases (NCG). We use wettability-patterned superhydrophilic tracks (filmwise condensing domains) on a mirror-finish (hydrophilic) aluminum surface that promotes DWC. Tapered, horizontal ``collection'' tracks are laid to create a Laplace pressure driven flow, which collects condensate from the mirror-finish domains and sends it to vertical ``drainage tracks'' for gravity-induced shedding. An optimal design is achieved by changing the fractional area of superhydrophilic tracks with respect to the overall plate surface, and augmenting capillary-driven condensate-drainage by adjusting the track spatial layout. The design facilitates pump-less condensate drainage and enhances DWC heat transfer on the mirror-finish regions. The study highlights the relative influences of the promoting and retarding effects of dropwise and filmwise condensation zones on the overall heat transfer improvement on the substrate. The study demonstrated ~ 34% heat transfer improvement on Aluminum surface for the optimized design.

  18. 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

  19. Wettability shifts caused by CO2 aging on mineral surfaces

    NASA Astrophysics Data System (ADS)

    Liang, B.; Clarens, A. F.

    2015-12-01

    Interfacial forces at the CO2/brine/mineral ternary interface have a well-established impact on multiphase flow properties through porous media. In the context of geologic carbon sequestration, this wettability will impact capillary pressure, residual trapping, and a variety of other key parameters of interest. While the wettability of CO2 on pure mineral and real rock sample have been studied a great deal over the past few year, very little is known about how the wettability of these rocks could change over long time horizons as CO2 interacts with species in the brine and on the mineral surface. In this work we sought to explore the role that dilute inorganic and organic species that are likely to exist in connate brines might have on a suite of mineral species. High-pressure contact angle experiments were carried out on a suite of polished mineral surfaces. Both static captive bubble and advancing/receding contact angle measurements were carried out. The effect of ionic strength, and in particular the valence of the dominant ions in the brine are found to have an important impact on the wettability which cannot be explained solely based on the shifts in the interfacial tension between the CO2 and brine. More significantly, three organic species, formate, acetate, and oxalate, all three of which are representative species commonly encountered in the saline aquifers that are considered target repositories for carbon sequestration. All three organic species show impacts on wettability, with the organics generally increasing the CO2 wetting of the mineral surface. Not all pure minerals respond the same to the presence of organics, with micas showing a more pronounced influence than quartz. Sandstone and limestone samples aged with different kinds of hydrocarbons, a surrogate for oil-bearing rocks, are generally more CO2-wet, with larger contact angles in the CO2/brine system. Over multiple days, the contact angle decreases, which could be attributed to partitioning

  20. Water wettability in nanoconfined environment

    NASA Astrophysics Data System (ADS)

    Zhou, YaHong; Guo, Wei; Jiang, Lei

    2014-05-01

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

  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. Toxic action of advanced glycation end products on cultured retinal capillary pericytes and endothelial cells: relevance to diabetic retinopathy.

    PubMed

    Chibber, R; Molinatti, P A; Rosatto, N; Lambourne, B; Kohner, E M

    1997-02-01

    The toxic effects of advanced glycation end products (AGEs) on bovine retinal capillary pericytes (BRP) and endothelial cells (BREC) were studied. AGE-modified bovine serum albumin (AGE-BSA) was toxic to BRP. At a concentration of 500 micrograms/ml it reduced the BRP number to 48 +/- 3% (p < 0.05) of untreated controls, as determined by cell counting with haemocytometer. AGE-BSA was also toxic to bovine aortic endothelial cells (BAEC) reducing cell number to 84 +/- 3.1% of untreated controls. Under similar conditions, low concentrations (62.5 micrograms/ml) of AGE-BSA were mitogenic to BREC increasing the cell proliferation to 156 +/- 11% (p < 0.05) above that of untreated controls. At a higher dose of 500 micrograms/ml AGE-BSA decreased the proliferation of BREC to 85 +/- 6% of untreated controls. Immunoblot analysis demonstrated that BRP and BREC express the p60 AGE-receptor. Retinal capillary bed from the human also stained positively for the p60 AGE-receptor. Addition of 0.25 micrograms/ml of p60 AGE-receptor antibody was able to block the effects of AGE-BSA on BRP and BREC. The level of binding of [125I]-labelled AGE-BSA to the cell surface was small but significant among the three cell types. There was also an increase in the internalized pool of radioligand in BRP and BREC but this was very much lower than in BAEC. In all the cell types the internalized pool of [125I]-labelled AGE-BSA was much larger than the amount associated with the cell surface. Degradation products were not detected in the media over the 24-h incubation of the cells with [125I]AGE-BSA. The binding of [125I]-labelled AGE-BSA to the cell surface was prevented by the addition of p60 AGE-receptor. These results suggest that the interaction of AGE-modified proteins with the membrane-bound AGE-receptor may play an important role in the pathogenesis of diabetic retinopathy.

  3. 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.

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

    SciTech Connect

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

    1992-09-01

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

  5. 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 θ from 5° (drainage) to 120° (imbibition). We demonstrate that wettability exerts a powerful influence on the invasion morphology of unfavorable mobility displacements: increasing θ 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.

  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

  7. About determining the wettability of coal surface

    NASA Astrophysics Data System (ADS)

    Arkhipov, V. A.; Basalaev, S. A.; Zolotorev, N. N.; Usanina, A. S.

    2016-09-01

    A new method of measuring the wettability of coal powders based on determining the mass fraction of wetted powder particles at their interaction with water droplets during the process of gravitational sedimentation in a transparent cell has been proposed. Wettability parameter is calculated from the results of measuring the dependence of spectral transmittance of laser emission in the cell on time of powder sedimentation.

  8. Wettability effects on droplet coalescence

    NASA Astrophysics Data System (ADS)

    Graham, Percival; de Pauw, Dennis; Dolatabadi, Ali

    2012-11-01

    Droplet impingement has been studied since 1895, with the works of A.M. Worthington. Throughout the past century, a variety of interesting phenomena have been uncovered. These include the bouncing of droplets off of each other or liquid pools, intricate droplet splashing mechanics, and droplets bouncing off of superhydrophobic surfaces; to name a few. In addition to intricate phenomena, droplet dynamics are relevant to many engineering applications, such as painting, spray coating ink-jet printing, and ice accumulation. These fields all involve interactions between droplets; therefore, studying droplet coalescence would benefit them greatly. The works presented include the coalescence of droplets with different impact conditions, various offsets, and at different wettabilities. Surface wettabilities studied are hydrophilic, hydrophobic and superhydrophobic. Fascinating phenomena observed include, bouncing of the impinging droplet off of the sessile droplet, sliding of the impinging droplet along the sessile droplet, and induced detachment on the sessile droplet on superhydrophobic surfaces. In order to capture the maximum spreading of the merged droplets, models related to coalescence of droplets in air and maximum spreading of a single droplet are combined to yield a new model to predict the maximum spreading of head-on droplet impact. Based on the free surface, and accuracy of the analytical model, droplet impact could be viewed as a mix of droplet coalescence in a gaseous media and droplet impact on a dry surface. Funding from NSERC.

  9. 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.

  10. 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 θ(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 θ(eq) smaller than a critical angle θ(c) depending on viscosity. A scaling analysis based on Navier-Stokes equations is presented at the end, and the predicted θ(c) matches with experimental observations without any additional fitting parameters.

  11. Determination of Labeled Fatty Acids Content in Milk Products, Infant Formula, and Adult/Pediatric Nutritional Formula by Capillary Gas Chromatography: Collaborative Study, Final Action 2012.13.

    PubMed

    Golay, Pierre-Alain; Moulin, Julie

    2016-01-01

    A collaborative study was conducted on AOAC First Action Method 2012.13 "Determination of Labeled Fatty Acids Content in Milk Products and Infant Formula by Capillary Gas Chromatography," which is based on an initial International Organization for Standardization (ISO)-International Dairy Federation (IDF) New Work Item that has been moved forward to ISO 16958:2015|IDF 231:2015 in November 2015. It was decided to merge the two activities after the agreement signed between ISO and AOAC in June 2012 to develop common standards and to avoid duplicate work. The collaborative study was performed after having provided highly satisfactory single-laboratory validation results [Golay, P.A., & Dong, Y. (2015) J. AOAC Int. 98, 1679-1696] that exceeded the performance criteria defined in AOAC Standard Method Performance Requirement (SMPR(®)) 2012.011 (September 29, 2012) on 12 products selected by the AOAC Stakeholder Panel on Infant Formula (SPIFAN). After a qualification period of 1 month, 18 laboratories participated in the fatty acids analysis of 12 different samples in duplicate. Six samples were selected to meet AOAC SPIFAN requirements (i.e., infant formula and adult nutritionals in powder and liquid formats), and the other Six samples were selected to meet ISO-IDF requirements (i.e., dairy products such as milk powder, liquid milk, cream, butter, infant formula with milk, and cheese). The fatty acids were analyzed directly in all samples without preliminary fat extraction, except in one sample (cheese). Powdered samples were analyzed after dissolution (i.e., reconstitution) in water, whereas liquid samples (or extracted fat) were analyzed directly. After addition of the internal standards solution [C11:0 fatty acid methyl ester (FAME) and C13:0 triacylglycerols (TAG)] to the samples, fatty acids attached to lipids were transformed into FAMEs by direct transesterification using methanolic sodium methoxide. FAMEs were separated using highly polar capillary GLC and were

  12. Determination of Labeled Fatty Acids Content in Milk Products, Infant Formula, and Adult/Pediatric Nutritional Formula by Capillary Gas Chromatography: Collaborative Study, Final Action 2012.13.

    PubMed

    Golay, Pierre-Alain; Moulin, Julie

    2016-01-01

    A collaborative study was conducted on AOAC First Action Method 2012.13 "Determination of Labeled Fatty Acids Content in Milk Products and Infant Formula by Capillary Gas Chromatography," which is based on an initial International Organization for Standardization (ISO)-International Dairy Federation (IDF) New Work Item that has been moved forward to ISO 16958:2015|IDF 231:2015 in November 2015. It was decided to merge the two activities after the agreement signed between ISO and AOAC in June 2012 to develop common standards and to avoid duplicate work. The collaborative study was performed after having provided highly satisfactory single-laboratory validation results [Golay, P.A., & Dong, Y. (2015) J. AOAC Int. 98, 1679-1696] that exceeded the performance criteria defined in AOAC Standard Method Performance Requirement (SMPR(®)) 2012.011 (September 29, 2012) on 12 products selected by the AOAC Stakeholder Panel on Infant Formula (SPIFAN). After a qualification period of 1 month, 18 laboratories participated in the fatty acids analysis of 12 different samples in duplicate. Six samples were selected to meet AOAC SPIFAN requirements (i.e., infant formula and adult nutritionals in powder and liquid formats), and the other Six samples were selected to meet ISO-IDF requirements (i.e., dairy products such as milk powder, liquid milk, cream, butter, infant formula with milk, and cheese). The fatty acids were analyzed directly in all samples without preliminary fat extraction, except in one sample (cheese). Powdered samples were analyzed after dissolution (i.e., reconstitution) in water, whereas liquid samples (or extracted fat) were analyzed directly. After addition of the internal standards solution [C11:0 fatty acid methyl ester (FAME) and C13:0 triacylglycerols (TAG)] to the samples, fatty acids attached to lipids were transformed into FAMEs by direct transesterification using methanolic sodium methoxide. FAMEs were separated using highly polar capillary GLC and were

  13. 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.

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

    PubMed

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

    2014-01-17

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

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

    PubMed Central

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

    2013-01-01

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

  16. Effect of Surface Wettability on Crack Dynamics and Morphology of Colloidal Films.

    PubMed

    Ghosh, Udita Uday; Chakraborty, Monojit; Bhandari, Aditya Bikram; Chakraborty, Suman; DasGupta, Sunando

    2015-06-01

    The effect of surface wettability on the dynamics of crack formation and their characteristics are examined during the drying of aqueous colloidal droplets (1 μL volume) containing nanoparticles (53 nm mean particle diameter, 1 w/w %). Thin colloidal films, formed during drying, rupture as a result of the evaporation-induced capillary pressure and exhibit microscopic cracks. The crack initiation and propagation velocity as well as the number of cracks are experimentally evaluated for substrates of varying wettability and correlated to their wetting nature. Atomic force and scanning electron microscopy are used to examine the region in the proximity of the crack including the particle arrangements near the fracture zone. The altered substrate-particle Derjaguin-Landau-Verwey-Overbeek (DLVO) interactions, as a consequence of the changed wettability, are theoretically evaluated and found to be consistent with the experimental observations. The resistance of the film to cracking is found to depend significantly on the substrate surface energy and quantified by the critical stress intensity factor, evaluated by analyzing images obtained from confocal microscopy. The results indicate the possibility of controlling crack dynamics and morphology by tuning the substrate wettability.

  17. Spontaneous wettability patterning via creasing instability.

    PubMed

    Chen, Dayong; McKinley, Gareth H; Cohen, Robert E

    2016-07-19

    Surfaces with patterned wettability contrast are important in industrial applications such as heat transfer, water collection, and particle separation. Traditional methods of fabricating such surfaces rely on microfabrication technologies, which are only applicable to certain substrates and are difficult to scale up and implement on curved surfaces. By taking advantage of a mechanical instability on a polyurethane elastomer film, we show that wettability patterns on both flat and curved surfaces can be generated spontaneously via a simple dip coating process. Variations in dipping time, sample prestress, and chemical treatment enable independent control of domain size (from about 100 to 500 μm), morphology, and wettability contrast, respectively. We characterize the wettability contrast using local surface energy measurements via the sessile droplet technique and tensiometry. PMID:27382170

  18. Capillary origami

    NASA Astrophysics Data System (ADS)

    Py, Charlotte; Doppler, Lionel; Bico, Jose; Roman, Benoit; Reverdy, Paul; Baroud, Charles

    2006-11-01

    The wet fur of a dog coming out of a pond assembles into bunches: this is the most common effect of capillary forces on elasticity structures (the hairs). From a practical point of view, the deformation of flexible elements by surface tension forces dramatically damages mechanical microsystems or lung airways, but also allows the self-organization of nanotube carpets into well defined clump patterns. But capillary forces may generate even more complex structures when flexible sheets are brought to contact with a liquid interface. Here we present experiments where surface tension folds up an elastic sheet around a deposited water droplet, and discuss the different possible shapes obtained. These self-folding origami may be used in microsy stems design as a convenient and robust way to fold two-dimensional planar patterns into 3-dimensional structures, since surface tension effects are enhanced at small scales.

  19. Wettability and silicone hydrogel lenses: a review.

    PubMed

    Keir, Nancy; Jones, Lyndon

    2013-01-01

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

  20. 21 CFR 864.6150 - Capillary blood collection tube.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class...

  1. 21 CFR 864.6150 - Capillary blood collection tube.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class...

  2. 21 CFR 864.6150 - Capillary blood collection tube.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class...

  3. 21 CFR 864.6150 - Capillary blood collection tube.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class...

  4. 21 CFR 864.6150 - Capillary blood collection tube.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Capillary blood collection tube. 864.6150 Section... blood collection tube. (a) Identification. A capillary blood collection tube is a plain or heparinized glass tube of very small diameter used to collect blood by capillary action. (b) Classification. Class...

  5. Rapid capillary filling via ion-water interactions over the nanoscale

    NASA Astrophysics Data System (ADS)

    Bakli, Chirodeep; Chakraborty, Suman

    2016-03-01

    Giant frictional resistances are grand challenges against the rapid filling of nanoscale capillaries, as encountered in a wide variety of applications ranging from nature to energy. It is commonly believed that partially wettable charged nanocapillaries fill up considerably slower, compared to completely wettable ones, under the influence of a complex interplay between interfacial tension and electrical interactions. In sharp contrast to this common belief, here we discover a new non-intuitive regime of rapid filling of charged capillaries over the nanometer scale, by virtue of which a partially wettable capillary may fill up comparatively faster than a completely wettable one. We attribute the fundamental origin of this remarkable behavior to ion-water interactions over interfacial scales. The underlying novel electro-hydrodynamic mechanism, as unveiled here, may provide deeper insights into the physico-chemical interactions leading to augmentations in the rates of nanocapillary filling over hydrophobic regimes, bearing far-reaching implications in the transport of biological fluids, enhanced oil recovery, and miniaturized energy harvesting applications.Giant frictional resistances are grand challenges against the rapid filling of nanoscale capillaries, as encountered in a wide variety of applications ranging from nature to energy. It is commonly believed that partially wettable charged nanocapillaries fill up considerably slower, compared to completely wettable ones, under the influence of a complex interplay between interfacial tension and electrical interactions. In sharp contrast to this common belief, here we discover a new non-intuitive regime of rapid filling of charged capillaries over the nanometer scale, by virtue of which a partially wettable capillary may fill up comparatively faster than a completely wettable one. We attribute the fundamental origin of this remarkable behavior to ion-water interactions over interfacial scales. The underlying novel

  6. 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.

  7. Control of surface wettability via strain engineering

    NASA Astrophysics Data System (ADS)

    Xiong, Wei; Liu, Jefferson Zhe; Zhang, Zhi-Liang; Zhen, Quan-Shui

    2013-08-01

    Reversible control of surface wettability has wide applications in lab-on-chip systems, tunable optical lenses, and microfluidic tools. Using a graphene sheet as a sample material and molecular dynamic simulations, we demonstrate that strain engineering can serve as an effective way to control the surface wettability. The contact angles θ of water droplets on a graphene vary from 72.5° to 106° under biaxial strains ranging from -10% to 10% that are applied on the graphene layer. For an intrinsic hydrophilic surface (at zero strain), the variation of θ upon the applied strains is more sensitive, i.e., from 0° to 74.8°. Overall the cosines of the contact angles exhibit a linear relation with respect to the strains. In light of the inherent dependence of the contact angle on liquid-solid interfacial energy, we develop an analytic model to show the cos θ as a linear function of the adsorption energy E ads of a single water molecule over the substrate surface. This model agrees with our molecular dynamic results very well. Together with the linear dependence of E ads on biaxial strains, we can thus understand the effect of strains on the surface wettability. Thanks to the ease of reversibly applying mechanical strains in micro/nano-electromechanical systems, we believe that strain engineering can be a promising means to achieve the reversibly control of surface wettability.

  8. 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; Deshcherevskiĭ 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

  9. A many-body dissipative particle dynamics study of forced water-oil displacement in capillary.

    PubMed

    Chen, Chen; Zhuang, Lin; Li, Xuefeng; Dong, Jinfeng; Lu, Juntao

    2012-01-17

    The forced water-oil displacement in capillary is a model that has important applications such as the groundwater remediation and the oil recovery. Whereas it is difficult for experimental studies to observe the displacement process in a capillary at nanoscale, the computational simulation is a unique approach in this regard. In the present work, the many-body dissipative particle dynamics (MDPD) method is employed to simulate the process of water-oil displacement in capillary with external force applied by a piston. As the property of all interfaces involved in this system can be manipulated independently, the dynamic displacement process is studied systematically under various conditions of distinct wettability of water in capillary and miscibility between water and oil as well as of different external forces. By analyzing the dependence of the starting force on the properties of water/capillary and water/oil interfaces, we find that there exist two different modes of the water-oil displacement. In the case of stronger water-oil interaction, the water particles cannot displace those oil particles sticking to the capillary wall, leaving a low oil recovery efficiency. To minimize the residual oil content in capillary, enhancing the wettability of water and reducing the external force will be beneficial. This simulation study provides microscopic insights into the water-oil displacement process in capillary and guiding information for relevant applications.

  10. Texture and wettability of metallic lotus leaves

    NASA Astrophysics Data System (ADS)

    Frankiewicz, C.; Attinger, D.

    2016-02-01

    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 superrepellent surfaces.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

  11. 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

  12. Action!

    ERIC Educational Resources Information Center

    Senese, Joseph

    1998-01-01

    A small group of teachers at one Illinois high school is helping to effect and promote change. Through the Action Research Laboratory (ARL), teams of teachers conduct collaborative action research to improve classroom practices. Data from the first two years of the ARL indicate that teachers are eager to participate in, and have thrived in, their…

  13. 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

    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

  14. Immiscible fluids in mixed wet porous media: the role of wettability correlations

    NASA Astrophysics Data System (ADS)

    Murison, Julie; Semin, Benoit; Baret, Jean-Christophe; Herminghaus, Stephan; Schroeter, Matthias; Brinkmann, Martin

    2013-11-01

    Various phenomena observed during immiscible displacement in a porous medium can be related to pore wall wettability. Petroleum engineers traditionally quantify the overall wettability of a rock sample in terms of the Ammot-Harvey or USBM index. To establish a link between these gloabl quantities and the pore-scale distribution of surface energies, we developed a series of model porous media. Using a variety of preparation methods, we are able to create dense beds of glass beads with the same average surface energy, differing only in the typical extension of the wetting and non-wetting surface domains. Experimental measurements of capillary pressure saturation curves for repeated imbibition and drainage show that the work dissipated in a complete cycle is monotonically increasing with the correlation length ξ of the surface energies. To test whether capillary hysteresis can be linked to specific features of the front morphology, we visualized the distribution of liquids by means of X-ray microtomography. The Minkowski measures volume, surface area, and Euler number are employed to characterize the interfacial shape. Differences of the front morphology during imbibition and drainage match with trends observed for the hysteresis loop opening.

  15. Bioinspired steel surfaces with extreme wettability contrast

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  16. Effect of the interfacial tension and wettability on the behaviour of unsaturated granular media

    NASA Astrophysics Data System (ADS)

    Taibi, Said; Dumont, Matthieu; Fleureau, Jean-Marie

    2009-06-01

    The concept of "effective stress extended to unsaturated soils" is one of the most discussed concepts in soil mechanics today. This concept enters in the formulation of the constitutive laws of elastic as well as elastoplastic solid phases, and controls the stress-strain relations, the volume changes and the strength of the solid skeleton, independently of the amplitude of the pore water pressure. These last years, several researchers showed that the extended effective stress concept remains an effective tool to describe qualitatively and quantitatively the unified mechanical behavior of the soils, assuring continuity between saturated and unsaturated domains. This paper presents the effect of the air-water surface tension and wettability of the solid particles by the liquid in the formulation of the capillary force between the particles; this force, integrated in a representative elementary volume (REV), makes it possible to define a "capillary" stress σ'cap(pc), function of the capillary pressure pc. Taking into account the surface tension in the formulation of the capillary stress σ' cap is far from being negligible. Whereas this effect is negligible when the water content tends towards 0, it quickly becomes very important when the water content reaches a few percents. Validations were carried out on various loading paths and various materials.

  17. 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.

  18. 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

  19. Capillary-inertial colloidal catapults upon drop coalescence

    NASA Astrophysics Data System (ADS)

    Chavez, Roger L.; Liu, Fangjie; Feng, James J.; Chen, Chuan-Hua

    2016-07-01

    Surface energy released upon drop coalescence is known to power the self-propelled jumping of liquid droplets on superhydrophobic solid surfaces, and the jumping droplets can additionally carry colloidal payloads toward self-cleaning. Here, we show that drop coalescence on a spherical particle leads to self-propelled launching of the particle from virtually any solid surface. The main prerequisite is an intermediate wettability of the particle, such that the momentum from the capillary-inertial drop coalescence process can be transferred to the particle. By momentum conservation, the launching velocity of the particle-drop complex is proportional to the capillary-inertial velocity based on the drop radius and to the fraction of the liquid mass in the total mass. The capillary-inertial catapult is not only an alternative mechanism for removing colloidal contaminants, but also a useful model system for studying ballistospore launching.

  20. 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.

  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. Wettability predictions at the oxide ceramic/metal interfaces

    SciTech Connect

    Chidambaram, P.R.; Edwards, G.R.

    1996-12-31

    The wettability of oxide ceramics are predicted using a model based on surface phase thermodynamics. Wetting occurs whenever the Gibbs free energy of wetting, {Delta}G{sub w} is negative. The model developed in this premise is illustrated using magnesium oxide ceramic as an example. The model predictions are verified both by using the wettability data available in the literature and by local experimentation. A wettability map delineating the wetting and non-wetting systems for magnesium oxide is drawn. The oxide wettability diagram, a plot of free energy versus temperature for both surface and bulk phases of technologically important oxide ceramics, is also constructed. This type of a wettability diagram can be advantageously used to evaluate the wettability of potential brazing alloys on oxide ceramics.

  3. 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.

  4. 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.

  5. Theoretical study on wettability of graphene/water interface

    NASA Astrophysics Data System (ADS)

    Ishimoto, Takayoshi

    2015-12-01

    We analyzed the interaction energy between water clusters and graphene model compound by using density functional theory. The mono- and multi-layer interaction of water on graphene models are regarded as the low and high contact angles, which correspond to the wettability of interface, respectively. We clearly found the size dependency of water molecules on graphene model compound for the wettability.

  6. Wettability changes in trichloroethylene-contaminated sandstone.

    PubMed

    Harrold, G; Gooddy, D C; Lerner, D N; Leharne, S A

    2001-04-01

    It is usually assumed that chlorinated solvent nonaqueous-phase liquids (NAPLs) are nonwetting with respect to water-saturated porous media. The focus of this work was to examine whether this supposition is appropriate for used trichloroethylene (TCE) samples. In this work, the term "used" indicates that the sample has been employed industrially and therefore contains solutes and breakdown products related to its previous use. The data obtained in this study indicate that exposure of initially water wet quartz slides to industrially used solvents can cause a contact angle change, measured through the aqueous phase, of 100 degrees with a maximum stable contact angle of 170 degrees (indicative of strong NAPL wetting characteristics) being recorded. The work on quartz slides was complemented by the use of sandstone cores. Wettability was measured using the Amott test. Used TCE again proved able to alter the wetting properties of sandstone to neutral wetting. The complexity of the industrially used samples precluded any realistic attempt to examine the agents causing these wetting changes. The data captured in these experiments were compared with laboratory grade TCE, and some attempts were made to synthesize known mixtures in order to replicate wetting changes. These experiments resulted in contact angle changes but did not alter the overall wettability of the quartz slides or sandstone cores. Finally the work reported here also demonstrates that increasing the duration of exposure to solvent has an important impact upon measured contact angle.

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

    PubMed

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

    2013-01-01

    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. PMID:24149467

  8. 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.

  9. Pool boiling of nanoparticle-modified surface with interlaced wettability

    PubMed Central

    2012-01-01

    This study investigated the pool boiling heat transfer under heating surfaces with various interlaced wettability. Nano-silica particles were used as the coating element to vary the interlaced wettability of the surface. The experimental results revealed that when the wettability of a surface is uniform, the critical heat flux increases with the more wettable surface; however, when the wettability of a surface is modified interlacedly, regardless of whether the modified region becomes more hydrophilic or hydrophobic, the critical heat flux is consistently higher than that of the isotropic surface. In addition, this study observed that critical heat flux was higher when the contact angle difference between the plain surface and the modified region was smaller. PMID:22607462

  10. Pool boiling of nanoparticle-modified surface with interlaced wettability.

    PubMed

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

    2012-05-18

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

  11. Pool boiling of nanoparticle-modified surface with interlaced wettability

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

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

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

    DOEpatents

    Rye,Robert R. , Yost,Frederick G.

    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. Effects of Pore-Scale Disorder on Fluid Displacement in Partially-Wettable Porous Media

    PubMed Central

    Holtzman, Ran

    2016-01-01

    We present a systematic, quantitative assessment of the impact of pore size disorder and its interplay with flow rates and wettability on immiscible displacement of a viscous fluid. Pore-scale simulations and micromodel experiments show that reducing disorder increases the displacement efficiency and compactness, minimizing the fluid-fluid interfacial area, through (i) trapping at low rates and (ii) viscous fingering at high rates. Increasing the wetting angle suppresses both trapping and fingering, hence reducing the sensitivity of the displacement to the underlying disorder. A modified capillary number Ca* that includes the impact of disorder λ on viscous forces (through pore connectivity) is direct related to λ, in par with previous works. Our findings bear important consequences on sweep efficiency and fluid mixing and reactions, which are key in applications such as microfluidics to carbon geosequestration, energy recovery, and soil aeration and remediation. PMID:27782194

  14. Stick-slip control in nanoscale boundary lubrication by surface wettability.

    PubMed

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

    PubMed

    Dixon, Angela; Takayama, Shuichi

    2010-10-01

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

  16. Flow Manipulation in Thread-Based Microfluidics by Tuning the Wettability of Wool.

    PubMed

    Jeon, So-Hyoun; Hwang, Ki-Hwan; Jung, Won Suk; Seo, Hyeon-Jin; Nam, Sung Woo; Boo, Jin-Hyo; Yun, Sang H

    2015-02-01

    Recent progress in thread-based microfluidic devices has provided portable and inexpensive field-based technologies enabling medical diagnostics, environmental monitoring, and food safety analysis. However, capillary-driven liquid flow in a single thread, a crucial aspect of thread-based microfluidics, is difficult to control. Among potential materials, hydrophobic wool thread is an appropriate candidate for liquid flow control in thread-based microfluidics because its wettability can be readily tuned by the introduction of a natural color pigment, thereby manipulating flow. Thus, utilizing natural wool thread as a channel, we demonstrate here that liquid flow manipulations, such as microselecting and micromixing, can be achieved by coating the complex Al(III) (Alum) brazilein onto wool thread. In addition to enabling flow control, the coated wool channels consisting entirely of naturally occurring substances will be beneficial for biological sensing devices. PMID:26349307

  17. Multiple capillary biochemical analyzer

    DOEpatents

    Dovichi, Norman J.; Zhang, Jian Z.

    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.

  18. 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.

  19. IMPACT OF CAPILLARY AND BOND NUMBERS ON RELATIVE PERMEABILITY

    SciTech Connect

    Kishore K. Mohanty

    2002-09-30

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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Intranasal lobular capillary haemangioma

    PubMed Central

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

    2014-01-01

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

  5. 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.

  6. Capillary zone electrophoresis

    SciTech Connect

    Jorgenson, J.W.; Lukacs, K.D.

    1983-10-21

    Zone electrophoresis in capillaries is a technique complementary to electrophoresis in supporting media, and each approach has its own particular advantages. Efficient heat transfer from small-diameter capillaries permits use of unusually high voltages, resulting in both high resolution and rapid analysis. Capillaries also seem well suited for automation. Our present electromigration injection technique is relatively straightforward and should be simple to automate. Capillaries are reusable, which is an advantage over gels. On-line electronic detection permits good quantification, further enhancing possibilities for fully automatic operation. The greatest obstacle to further development and utilization of capillaries is the requirement of extremely sensitive detectors, and more types of detectors with higher sensitivity are greatly needed. A better understanding of capillary surface modification will also be important, both for improved capillary surface deactivation and for better control over electroosmotic flow. Capillaries should provide an ideal system in which to explore nonaqueous separation media. The prospects for nonaqueous media in electrophoresis are similar to those in electrochemistry, and capillaries should prove an excellent system in which to begin their study. 18 refs., 8 figs.

  7. Wettability analysis of tin-based, lead free solders

    SciTech Connect

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

    1992-01-01

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

  8. 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.

  9. PWB solder wettability after simulated storage

    SciTech Connect

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

    1996-03-01

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

  10. Bacterial surface layer proteins as a novel capillary coating material for capillary electrophoretic separations.

    PubMed

    Moreno-Gordaliza, Estefanía; Stigter, Edwin C A; Lindenburg, Petrus W; Hankemeier, Thomas

    2016-06-01

    A novel concept for stable coating in capillary electrophoresis, based on recrystallization of surface layer proteins on hydrophobized fused silica capillaries, was demonstrated. Surface layer protein A (SlpA) from Lactobacillus acidophilus bacteria was extracted, purified and used for coating pre-silanized glass substrates presenting different surface wettabilities (either hydrophobic or hydrophilic). Contact angle determination on SlpA-coated hydrophobic silica slides showed that the surfaces turned to hydrophilic after coating (53 ± 5°), due to a protein monolayer formation by protein-surface hydrophobic interactions. Visualization by atomic force microscopy demonstrated the presence of a SlpA layer on methylated silica slides displaying a surface roughness of 0.44 ± 0.02 nm. Additionally, a protein layer was visualized by fluorescence microscopy in methylated silica capillaries coated with SlpA and fluorescein isothiocyanate-labeled. The SlpA-coating showed an outstanding stability, even after treatment with 20 mM NaOH (pH 12.3). The electroosmotic flow in coated capillaries showed a partial suppression at pH 7.50 (3.8 ± 0.5 10(-9) m(2) V(-1) s(-1)) when compared with unmodified fused silica (5.9 ± 0.1 10(-8) m(2) V(-1) s(-1)). To demonstrate the potential of this novel coating, the SlpA-coated capillaries were applied for the first time for electrophoretic separation, and proved to be very suitable for the isotachophoretic separation of lipoproteins in human serum. The separations showed a high degree of repeatability (absolute migration times with 1.1-1.8% coefficient-of-variation (CV) within a day) and 2-3% CV inter-capillary reproducibility. The capillaries were stable for more than 100 runs at pH 9.40, and showed to be an exceptional alternative for challenging electrophoretic separations at long-term use. PMID:27155306

  11. 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}.

  12. Coalescence of sessile microdroplets subject to a wettability gradient on a solid surface

    NASA Astrophysics Data System (ADS)

    Ahmadlouydarab, Majid; Lan, Chuanjin; Das, Arup Kumar; Ma, Yanbao

    2016-09-01

    While there are intensive studies on the coalescence of sessile macroscale droplets, there is little study on the coalescence of sessile microdroplets. In this paper, the coalescence process of two sessile microdroplets is studied by using a many-body dissipative particle dynamics numerical method. A comprehensive parametric study is conducted to investigate the effects on the coalescence process from the wettability gradient, hydrophilicity of the solid surface, and symmetric or asymmetric configurations. A water bridge is formed after two microdroplets contact. The temporal evolution of the coalescence process is characterized by the water bridge's radii parallel to the solid surface (Wm) and perpendicular to the solid surface (Hm). It is found that the changes of both Hm and Wm with time follow a power law; i.e., Hm=β1τβ and Wm=α1τα . The growth of Hm and Wm depends on the hydrophilicity of the substrate. Wm grows faster than Hm on a hydrophilic surface, and Hm grows faster than Wm on a hydrophobic surface. This is due to the strong competition between capillary forces induced by the water-bridge curvature and the solid substrate hydrophobicity. Also, flow structure analysis shows that regardless of the coalescence type once the liquid bridge is formed the liquid flow direction inside the capillary bridge is to expand the bridge radius. Finally, we do not observe oscillation of the merged droplet during the coalescence process, possibly due to the significant effects of the viscous forces.

  13. 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

  14. 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

  15. Wettability Patterning for Enhanced Dropwise Condensation

    NASA Astrophysics Data System (ADS)

    Ghosh, Aritra; Ganguly, Ranjan; Megaridis, Constantine

    2014-11-01

    Dropwise condensation (DwC), in order to be sustainable, requires removal of the condensate droplets. This removal is frequently facilitated by gravity. The rate of DwC heat transfer depends strongly on the maximum departing droplet diameter. Based on wettability patterning, we present a facile technique designed to control the maximum droplet size in DwC within vapor/air atmospheres, and demonstrate how this approach can be used to enhance the corresponding heat transfer rate. We examine various hydrophilic-superhydrophilic patterns, which, respectively sustain DwC and filmwise (FwC) condensation on the substrate. The fabrication method does notemploy any hydrophobizing agent. By juxtaposing parallel lines of hydrophilic (CA ~ 78°) and superhydrophilic (CA ~ 0°) regions on the condensing surface, we create alternating domains of DwC and FwC. The average droplet size on the DwC domain is reduced by ~ 60% compared to the theoretical maximum, which corresponds to the line width. We compare heat transfer rate between unpatternend DwC surfaces and patterned DwC surfaces. Even after sacrificing 40% of condensing area, we achieve up to 20% improvement in condensate collection rate using an interdigitated superhydrophilic pattern, inspired by the vein network of plant leaves. The bioinspired interdigitated pattern is found to outperform the straight hydrophilic-superhydrophilic pattern, particularly under higher vapor loadings in an air/vapor ambient atmosphere. NSF STTR Grant 1331817 via NBD Nano.

  16. Controlling the wettability of hierarchically structured thermoplastics.

    PubMed

    Cortese, Barbara; Morgan, Hywel

    2012-01-10

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

  17. Capillary micro-switches

    NASA Astrophysics Data System (ADS)

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

    2002-11-01

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

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

    SciTech Connect

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

    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

  19. 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.

  20. 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.

  1. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Li, Qingbo; Lu, Xiandan

    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.

  2. Multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Chang, Huan-Tsang; Fung, Eliza N.; Li, Qingbo; Lu, Xiandan

    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.

  3. 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

  4. Capillary rise of superspreaders.

    PubMed

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

    2011-09-15

    Trisiloxane surfactants, known as 'superspreaders', are commonly employed in numerous applications where enhanced wetting is of the utmost importance. The underlying mechanisms of superspreader wetting have been a focus of scientific interest for ca. 2 decades, and a number of mechanisms have been proposed to explain the unique trisiloxane dynamics. We have studied trisiloxane behaviour in thin capillaries to get further insight into their interfacial activity. Additionally, our knowledge of the capillary rise of superspreaders is surprisingly limited, and the effect of this extraordinary group of surfactants on capillary phenomena has been largely overlooked. Diffusion was confirmed to be the limiting factor of trisiloxane behaviour. A tentative theoretical explanation for the phenomenon studied and an appropriate mathematical model are presented. It is concluded that the enhancement of wetting due to surfactant addition is also a function of geometry: the effect is clear for a sessile drop, but more complex and less beneficial in a capillary.

  5. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    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.

  6. Displaced capillary dies

    DOEpatents

    Kalejs, Juris P.; Chalmers, Bruce; Surek, Thomas

    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.

  7. 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.

  8. 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.

    PubMed

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

    2006-08-01

    NMR relaxation time distributions of water (1)H 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.

  9. Simple and inexpensive micro-capillary devices for generating composite emulsions

    NASA Astrophysics Data System (ADS)

    Li, Erqiang; Zhang, Jiaming; Thoroddsen, Sigurdur

    2012-11-01

    All-glass microfluidic devices have attracted recent attention due to their excellent chemical robustness, bio-compatibility, optical properties and the ease of modifying their surface wettability. Herein we report the usage of a single tapered cylindrical glass capillary and microscope slides to fabricate simple and inexpensive all-glass microfluidic devices that are capable of producing monodisperse double emulsions. Triple emulsion droplets of water-in-oil-in-water-in-oil (W/O/W/O) or O/W/O/W phases can also be stably generated by adding another cylindrical capillary next to the outlet of the first capillary. In addition, by careful controlling the wettability of the inner surface of the first capillary, multi-component emulsion droplets of (gas and water)-in-oil-in-water ((G+W)/O/W) phases can also be stably produced. Such gas-laden emulsion drops may be beneficial for bio-related applications where oxygen supply is required. The relationship between the flow parameters and the resulting number of encapsulated droplets and the emulsion droplet sizes, have been investigated, for all of these various higher order emulsions.

  10. 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.

  11. Capillary saturation and desaturation.

    PubMed

    Hilfer, R; Armstrong, R T; Berg, S; Georgiadis, A; Ott, H

    2015-12-01

    Capillary desaturation experiments produce disconnected (trapped) ganglia of mesoscopic sizes intermediate between pore size and system size. Experimental evidence for interactions between these mesoscale clusters during desaturation is analyzed and discussed within the established microscopic and macroscopic laws of Newton, Young-Laplace, and Darcy. A theoretical expression for capillary number correlations is introduced that seems to have remained unnoticed. It expresses capillary desaturation curves in terms of stationary capillary pressures and relative permeabilities. The theoretical expression shows that the plateau saturation in capillary desaturation curves may in general differ from the residual nonwetting saturation defined through the saturation limit of the main hysteresis loop. Hysteresis effects as well as the difference between wetting and nonwetting fluids are introduced into the analysis of capillary desaturation experiments. The article examines experiments with different desaturation protocols and discusses the existence of a mesoscopic length scale intermediate between pore scale and sample scale. The theoretical expression is derived entirely within the existing traditional theory of two-phase flow in porous media and compared to a recent experiment. PMID:26764820

  12. Doping-Induced Tunable Wettability and Adhesion of Graphene.

    PubMed

    Ashraf, Ali; Wu, Yanbin; Wang, Michael Cai; Yong, Keong; Sun, Tao; Jing, Yuhang; Haasch, Richard T; Aluru, Narayana R; Nam, SungWoo

    2016-07-13

    We report that substrate doping-induced charge carrier density modulation leads to the tunable wettability and adhesion of graphene. Graphene's water contact angle changes by as much as 13° as a result of a 300 meV change in doping level. Upon either n- or p-type doping with subsurface polyelectrolytes, graphene exhibits increased hydrophilicity. Adhesion force measurements using a hydrophobic self-assembled monolayer-coated atomic force microscopy probe reveal enhanced attraction toward undoped graphene, consistent with wettability modulation. This doping-induced wettability modulation is also achieved via a lateral metal-graphene heterojunction or subsurface metal doping. Combined first-principles and atomistic calculations show that doping modulates the binding energy between water and graphene and thus increases its hydrophilicity. Our study suggests for the first time that the doping-induced modulation of the charge carrier density in graphene influences its wettability and adhesion. This opens up unique and new opportunities for the tunable wettability and adhesion of graphene for advanced coating materials and transducers.

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

    NASA Astrophysics Data System (ADS)

    Moumen, Nadjoua

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

  14. 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 (20μL) 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 μm). 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

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

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  16. Environmental Applications of Interfacial Materials with Special Wettability.

    PubMed

    Wang, Zhangxin; Elimelech, Menachem; Lin, Shihong

    2016-03-01

    Interfacial materials with special wettability have become a burgeoning research area in materials science in the past decade. The unique surface properties of materials and interfaces generated by biomimetic approaches can be leveraged to develop effective solutions to challenging environmental problems. This critical review presents the concept, mechanisms, and fabrication techniques of interfacial materials with special wettability, and assesses the environmental applications of these materials for oil-water separation, membrane-based water purification and desalination, biofouling control, high performance vapor condensation, and atmospheric water collection. We also highlight the most promising properties of interfacial materials with special wettability that enable innovative environmental applications and discuss the practical challenges for large-scale implementation of these novel materials.

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

    PubMed

    Boncel, Sławomir; Walczak, Krzysztof Z; Koziol, Krzysztof K K

    2011-01-01

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

  18. Fabrication of superhydrophobic polyaniline films with rapidly switchable wettability

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  19. Wettability and fluid saturations determined from NMR T1 distributions.

    PubMed

    Howard, J J

    1994-01-01

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

  20. Moisture and aging effects of solder wettability of copper surfaces

    SciTech Connect

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

    1996-12-01

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

  1. Gas-Filled Capillary Model

    NASA Astrophysics Data System (ADS)

    Steinhauer, L. C.; Kimura, W. D.

    2006-11-01

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

  2. Derivatization in Capillary Electrophoresis.

    PubMed

    Marina, M Luisa; Castro-Puyana, María

    2016-01-01

    Capillary electrophoresis is a well-established separation technique in analytical research laboratories worldwide. Its interesting advantages make CE an efficient and potent alternative to other chromatographic techniques. However, it is also recognized that its main drawback is the relatively poor sensitivity when using optical detection. One way to overcome this limitation is to perform a derivatization reaction which is intended to provide the analyte more suitable analytical characteristics enabling a high sensitive detection. Based on the analytical step where the CE derivatization takes place, it can be classified as precapillary (before separation), in-capillary (during separation), or postcapillary (after separation). This chapter describes the application of four different derivatization protocols (in-capillary and precapillary modes) to carry out the achiral and chiral analysis of different compounds in food and biological samples with three different detection modes (UV, LIF, and MS). PMID:27645730

  3. Capillary stretching of fibers

    NASA Astrophysics Data System (ADS)

    Duprat, C.; Protiere, S.

    2015-09-01

    We study the interaction of a finite volume of liquid with two parallel thin flexible fibers. A tension along the fibers is imposed and may be varied. We report two morphologies, i.e. two types of wet adhesion: a weak capillary adhesion, where a liquid drop bridges the fibers, and a strong elastocapillary adhesion where the liquid is spread between two collapsed fibers. We show that geometry, capillarity and stretching are the key parameters at play. We describe the collapse and detachment of the fibers as a function of two nondimensional parameters, arising from the geometry of the system and a balance between capillary and stretching energies. In addition, we show that the morphology, thus the capillary adhesion, can be controlled by changing the tension within the fibers.

  4. 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.

  5. Droplet impact on a porous substrate: a capillary tube model

    NASA Astrophysics Data System (ADS)

    Ding, Hang; Theofanous, Theo

    2009-11-01

    The dynamics of impacting (spreading, penetrating) a droplet on a porous substrate, modeled by an array of capillary tubes, is studied numerically using diffuse interface methods. The absorption rate depends on the diameter ratio of the capillary tube to the droplet, wettability, and liquid properties. The flow dynamics is resolved by solving the Navier-Stokes equations and interface capturing is governed by the Cahn-Hilliard equation. Contact-angle hysteresis is included (Ding&Spelt 2008) and the stress singularity at moving contact lines is relieved using a diffuse interface model (Seppecher 1996; Jaqcmin 2000). The model is validated by studying the evolution of a droplet initially resting on a porous substrate and by comparison to drop-impact experiments involving just one capillary tube (Kogan et al 2008). Comparisons with analytical solutions and results available in the literature (e.g. Hilpert & Ben-David 2009) are presented. Through parametric simulations over relevant ranges of Reynolds and Ohnesorge numbers and contact angles, impact regime maps are derived.

  6. Wettability on Inner and Outer Surface of Single Carbon Nanotubes.

    PubMed

    Yamada, Yutaka; Takahashi, Koji; Takata, Yasuyuki; Sefiane, Khellil

    2016-07-19

    The surface wettability of a liquid on the inner and outer surface of single carbon nanotubes (CNTs) was experimentally investigated. Although these contact angles on both surfaces were previously studied separately, the available data are of limited help to elucidate the effect of curvature orientation (concave or convex) on wettability due to the difference in surface structure. Here, we report on the three-phase contact region and wettability on the outer surface of CNT during the dipping and withdrawing experiment of CNT into an ionic liquid. Furthermore, the wettability on the inner surface was measured using a liquid within the same CNT. Our results show that the contact angle on the outer surface of the CNT is larger than that on the flat surface and that on the inner surface is smaller than that on the flat one. These findings suggest that the surface curvature orientation has a noticeable effect on the contact angle at the nanoscale because both inner and outer surfaces expose the same graphite wall structure and the contact line tension will be negligible in this situation. The presented results are rationalized using the free energy balance of liquid on curved surfaces. PMID:27351126

  7. Wettability control on multiphase flow in patterned microfluidics.

    PubMed

    Zhao, Benzhong; MacMinn, Christopher W; Juanes, Ruben

    2016-09-13

    Multiphase flow in porous media is important in many natural and industrial processes, including geologic CO2 sequestration, enhanced oil recovery, and water infiltration into soil. Although it is well known that the wetting properties of porous media can vary drastically depending on the type of media and pore fluids, the effect of wettability on multiphase flow continues to challenge our microscopic and macroscopic descriptions. Here, we study the impact of wettability on viscously unfavorable fluid-fluid displacement in disordered media by means of high-resolution imaging in microfluidic flow cells patterned with vertical posts. By systematically varying the wettability of the flow cell over a wide range of contact angles, we find that increasing the substrate's affinity to the invading fluid results in more efficient displacement of the defending fluid up to a critical wetting transition, beyond which the trend is reversed. We identify the pore-scale mechanisms-cooperative pore filling (increasing displacement efficiency) and corner flow (decreasing displacement efficiency)-responsible for this macroscale behavior, and show that they rely on the inherent 3D nature of interfacial flows, even in quasi-2D media. Our results demonstrate the powerful control of wettability on multiphase flow in porous media, and show that the markedly different invasion protocols that emerge-from pore filling to postbridging-are determined by physical mechanisms that are missing from current pore-scale and continuum-scale descriptions. PMID:27559089

  8. Wettability of Nafion and Nafion/Vulcan carbon composite films.

    PubMed

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

    2012-04-24

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

  9. Slide, Sweep and Vanish: Droplet manipulation by wettability engineering

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    Achieving controlled droplet transport on substrates is important for multiphase heat transfer, water harvesting and lab-on-chip applications. We use a facile, scalable surface wettability engineering approach to generate wettability patterned surfaces that comprise of superhydrophilic tracks of various geometrical patterns and length scales (μm -mm) on superhydrophobic backgrounds. Liquid transport on such surfaces harnesses the force arising from the spatial contrast of surface energy on the substrate, providing rapid actuation for micro and nanoliter drops. Considering a variety of dimensions, shapes and strategic locations of the superhydrophilic patterns on the substrate, effective modes of droplet transport through hemiwicking and Laplace pressure-driven flow are analyzed. The work provides proof-of-concept for salient digital microfluidic tasks, e.g. droplet capture, transport, merging and dispensing on such patterned substrates. This droplet manipulation is pumpless and fast. With suitable patterns and wettability contrast, we demonstrate on-chip droplet transport speeds of O(10 cm/s). The study examines the geometric and surface wettability parameters for optimal substrate design for droplet manipulation. On leave from Jadavpur University, India.

  10. 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

  11. Wettability changes in polyether impression materials subjected to immersion disinfection

    PubMed Central

    Shetty, Shweta; Kamat, Giridhar; Shetty, Rajesh

    2013-01-01

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

  12. 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.

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

    PubMed

    Zoueshtiagh, Farzam; Baudoin, Michael; Guerrin, David

    2014-12-21

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

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

    PubMed

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

    2012-06-15

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

  15. Underwater Spontaneous Pumpless Transportation of Nonpolar Organic Liquids on Extreme Wettability Patterns.

    PubMed

    Huang, Shuai; Song, Jinlong; Lu, Yao; Chen, Faze; Zheng, Huanxi; Yang, Xiaolong; Liu, Xin; Sun, Jing; Carmalt, Claire J; Parkin, Ivan P; Xu, Wenji

    2016-02-10

    Spontaneous pumpless transportation (SPT) of liquids has generated tremendous demands in microfluidic systems and advanced devices. However, the transportation of nonpolar organic liquids on open platforms underwater remains a challenge because most existing SPT systems are only designed for use in air. Here, we report a surface-tension-driven SPT system to transport various nonpolar organic liquids using underwater extreme wettability patterns. The patterns were fabricated with a wedge-shaped superoleophilic track on a superoleophobic background by combining CuCl2 etching, stearic acid modification, and mask-based nitrogen cold plasma treatment. Three types of underwater SPT processes-horizontal transport, tilted transport, and directional transport-were studied experimentally and theoretically. For horizontal SPT and tilted SPT, the capillary force was the main driving force, which depended on the wedge angle of the superoleophilic track. The excellent transportation ability of horizontal SPT of underwater liquid droplets was obtained at a wedge angle of 3-5°. The maximum moving height of organic liquids on the tilted SPT transport was obtained at an angle of 8°. For directional SPT, organic liquids did not drop off in the moving process because of the constraint imposed by surface tension, resulting in the sustained directional transport with long distances and complex trajectories.

  16. Noise suppressing capillary separation system

    DOEpatents

    Yeung, Edward S.; Xue, Yongjun

    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.

  17. [Venoruton and capillary permeability].

    PubMed

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

    1989-05-01

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

  18. Enantioseparations by capillary electrochromatography.

    PubMed

    Fanali, S; Catarcini, P; Blaschke, G; Chankvetadze, B

    2001-09-01

    The review summarizes recent developments in enantioseparations by capillary electrochromatography (CEC). Selected fundamental aspects of CEC are discussed in order to stress those features which may allow the success of this technique in the competitive field of enantioseparations. In addition, the comparative characteristics of the different modes of chiral CEC and the stationary phases are presented. The effects of the characteristics of the stationary and liquid phases and operational conditions on the separation results are discussed. Finally, some future trends are briefly addressed.

  19. Carbon nanotube patterning with capillary micromolding of catalyst.

    PubMed

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

    2007-11-01

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

  20. Carbon nanotube patterning with capillary micromolding of catalyst.

    PubMed

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

    2007-11-01

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

  1. WAG injection to reduce capillary entrapment in small-scale heterogeneities

    SciTech Connect

    Lingen, P.P. van; Barzanji, O.H.M.; Kruijsdijk, C.P.J.W. van

    1996-12-31

    We present an experimental study of water-alternate-gas (WAG) injection, or more accurately simultaneous water and gas injection (SWAG) as a means to reduce the capillary entrapment of oil in small (centimeter) scale reservoir heterogeneities. We describe the physical principle of the displacement method, which we illustrate with simulation results. In the experimental study, we compare the displacement efficiency of water injection and SWAG injection in scaled models with heterogeneity in wettability and grain size distribution. In these experiments, the average WAG recovery was twice as high as the water flood recovery.

  2. Automated Parallel Capillary Electrophoretic System

    DOEpatents

    Li, Qingbo; Kane, Thomas E.; Liu, Changsheng; Sonnenschein, Bernard; Sharer, Michael V.; Kernan, John R.

    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.

  3. 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.

  4. Powder wettability at a static air-water interface.

    PubMed

    Dupas, Julien; Forny, Laurent; Ramaioli, Marco

    2015-06-15

    The reconstitution of a beverage from a dehydrated powder involves several physical mechanisms that determine the practical difficulty to obtain a homogeneous drink in a convenient way and within an acceptable time for the preparation of a beverage. When pouring powder onto static water, the first hurdle to overcome is the air-water interface. We propose a model to predict the percentage of powder crossing the interface in 45 s, namely the duration relevant for this application. We highlight theoretically the determinant role of the contact angle and of the particle size distribution. We validate experimentally the model for single spheres and use it to predict the wettability performance of commercial food powders for different contact angles and particles sizes. A good agreement is obtained when comparing the predictions and the wettability of the tested powders. PMID:25721855

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

    PubMed

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

    2015-01-19

    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.

  6. Altering wettability to recover more oil from tight formations

    DOE PAGES

    Brady, Patrick V.; Bryan, Charles R.; Thyne, Geoffrey; Li, Huina

    2016-06-03

    We describe here a method for chemically modifying fracturing fluids and overflushes to chemically increase oil recovery from tight formations. Oil wetting of tight formations is usually controlled by adhesion to illite, kerogen, or both; adhesion to carbonate minerals may also play a role. Oil-illite adhesion is sensitive to salinity, dissolved divalent cation content, and pH. We measure oil-rock adhesion with middle Bakken formation oil and core to verify a surface complexation model of reservoir wettability. The agreement between the model and experiments suggests that wettability trends in tight formations can be quantitatively predicted and that fracturing fluid and overflushmore » compositions can be individually tailored to increase oil recovery.« less

  7. 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

  8. Comparison of capillary pressure relationships of organic liquid water systems containing an organic acid or base

    NASA Astrophysics Data System (ADS)

    Lord, D. L.; Demond, A. H.; Hayes, K. F.

    2005-04-01

    The presence of surface-active solutes such as organic acids and bases may have a profound influence on the transport of organic liquid contaminants through their impact on the constitutive relationship of capillary pressure vs. saturation. This relationship is a function of the interfacial tension and wettability of the system, which, in turn, depend on the pH and the concentration of organic acids and bases that are present. This study examines the impact of pH and the concentration on the interfacial tension, contact angle, and capillary pressure of systems consisting of tetrachloroethylene, water, and quartz containing either octanoic acid or dodecylamine. In general, the ionic form of the solute tended to remain in the aqueous phase and reduced the capillary pressure through its impact on the interfacial tension and contact angle; on the other hand, the neutral form of the solute partitioned into the organic liquid phase and had a lesser impact on the capillary pressure for the same total mass of solute. A comparison of these data with data generated in previous research in similar systems where o-xylene was the organic liquid showed that the trends are analogous. Thus, the behavior of these two solvent systems seems to be driven primarily by the aqueous phase speciation of the solute, and the differences between the capillary pressure relationships for the two systems could be attributed to the pure system interfacial tension.

  9. The Influence of Wettability Hysteresis on NAPL Source Zone Architecture

    NASA Astrophysics Data System (ADS)

    Ryder, J. L.; Demond, A. H.

    2008-12-01

    Variation in wettability may create heterogeneous source zone architecture because of its impact on the distribution and flow pathways of NAPLs. Wettability, measured by the contact angle, is a three phase property that depends on the composition of the solid and liquid phases. Wettability hysteresis, the change in contact angle depending on the order of fluid contact, results in materials that are conditionally NAPL wet. Contact angles were measured for three organic carbonaceous natural soil materials (two shales and a coal), three inorganic carbonaceous mineral materials (graphite, dolomite, and calcite), and two additional mineral materials (quartz and talc). The fluid pairings included air-water and several halogenated NAPL-water systems. Three solids (quartz, calcite, and dolomite) were unconditionally water wet while five solids (the shales, coal, graphite, and talc) were conditionally NAPL wet if NAPL had contacted the dry surface before the introduction of water to the system. Composition measurements showed that wettability hysteresis is negatively correlated with oxygen content, suggesting that once a solid is contacted by water, polar forces allow the formation of an intractable water film at the surface which prevents NAPL drops from spreading. Surface free energy analysis was used to confirm that the presence of a water film prevents the NAPL from spreading over conditionally NAPL-wet solids once they have been contacted by water. In the vadose zone, solids that are conditionally NAPL-wet may allow NAPL to enter smaller soil pores, thus allowing a wider spatial distribution of NAPL. In the saturated zone, a water film will be present on the grains making up the porous media when NAPL enters the system (if outside of the zone impacted by water table fluctuations. Thus, it is unlikely that NAPL can exist as a wetting phase in the saturated zone, unless the balance of surface forces is altered by the presence of surfactants.

  10. Nanopore Connectivity, Wettability and Fluid Migration in Mudrocks

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Hu, Q.; Barber, T.; Md Golam, K.

    2015-12-01

    Micro(nano)scopic pore characteristics (e.g., pore size, pore-size distribution, and pore connectivity) of mudrocks, implicated by their mixed wettability, control macroscopic fluid flow and hydrocarbon production. This work discusses various approaches to investigating pore structure (both geometry and topology) of several mudrocks of leading U.S. plays (Barnett, Bakken/Three Forks, and Utica), and the presence and connection of mixed wettability associated with compositional phases. Results show that these mudrocks have very limited edge-accessible pore spaces. This is shown from low pore connectivity behavior of fluid imbibition, steep decline of edge-accessible porosity from vacuum saturation, the heterogeneous presence of only trace amount of diffusing tracers beyond a few mm from a sample edge, and limited connected pathways from high-pressure injection of traced n-decane at 414 MPa. As mudrocks contain distinct hydrophobic organic materials (e.g., kerogen), as well as hydrophilic and/or hydrophobic minerals, different nano-sized tracers in two wettability fluids (API brine and n-decane) were developed to interrogate their pore spaces and connectivity. For two molecular tracers in n-decane with the sizes of 1.393 nm×0.287 nm×0.178 nm for 1-iododecane and 1.273 nm×0.919 nm×0.785 nm for trichlorooxobis (triphenylphosphine) rhenium, much less penetration was observed for wider molecules of organic-Re in these mudrocks with median pore-throats of around 5 nm, indicating the entangling of nano-sized molecules in nanopore spaces of mudrocks. The sparse nanopore space connection within the mudrock matrix, implicated by mixed wettability, could lead to limited movement of nano-sized hydrocarbon molecules and fracture-matrix interactions in fractured reservoirs, and consequently steep initial production decline and low recovery.

  11. Capillary electrophoresis for drug analysis in body fluids.

    PubMed

    Thormann, W; Zhang, C X; Schmutz, A

    1996-08-01

    Capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MECC) represent attractive methods for the determination of drugs and metabolites in body fluids. In CZE, minute (nanoliter) quantities of samples are applied to the beginning of a fused-silica capillary filled with buffer. On application of a high-voltage DC field, charged solutes begin to separate and are swept through the capillary by the combined action of electrophoresis and electroosmotic bulk flow and are on-column detected toward the capillary end. In MECC, the buffer contains charged micelles (e.g., dodecyl sulfate micelles) and both uncharged and charged solutes separate based on differential partitioning between the micelles and the surrounding buffer and, if charged, also by differential charge effects, including electrophoresis. Based on validated MECC drug assays developed in our laboratory, key aspects of measuring drug levels by MECC, including sample preparation, solute detection and identification, quantitation, reproducibility, and quality assurance are discussed. Drug levels determined by MECC are shown to be in good agreement with those obtained by nonisotopic immunoassays and/or high-performance liquid chromatography (HPLC). Using on-column multi-wavelength detection, this technology is also well suited for toxicological drug screening and confirmation and for the exploration of drug metabolism. Compared with HPLC and gas chromatography, capillary electrophoresis has distinct advantages, including automation, small sample size, minimal sample preparation, use of very small amounts of organic solvents and inexpensive chemicals, ease of buffer change and method development, and low cost of capillary columns. Electrokinetic capillary assays are complementary to the widely employed immunoassays. The state of the art and the pros and cons of capillary electrophoresis for the determination of drugs in body fluids are discussed with the goal of encouraging

  12. 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

  13. 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

  14. Capillary reference half-cell

    DOEpatents

    Hall, Stephen H.

    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.

  15. 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.

  16. Stability of Constrained Capillary Surfaces

    NASA Astrophysics Data System (ADS)

    Bostwick, J. B.; Steen, P. H.

    2015-01-01

    A capillary surface is an interface between two fluids whose shape is determined primarily by surface tension. Sessile drops, liquid bridges, rivulets, and liquid drops on fibers are all examples of capillary shapes influenced by contact with a solid. Capillary shapes can reconfigure spontaneously or exhibit natural oscillations, reflecting static or dynamic instabilities, respectively. Both instabilities are related, and a review of static stability precedes the dynamic case. The focus of the dynamic case here is the hydrodynamic stability of capillary surfaces subject to constraints of (a) volume conservation, (b) contact-line boundary conditions, and (c) the geometry of the supporting surface.

  17. Effect of capillary-condensed water on the dynamic friction force at nanoasperity contacts

    NASA Astrophysics Data System (ADS)

    Sirghi, L.

    2003-05-01

    A single nanoasperity contact in ambient air is usually wetted by capillary condensation of water vapor and is surrounded by a water meniscus. This phenomenon strongly affects the contact friction, not only by the effect of meniscus loading force (superficial tension and capillary forces), but also by a friction force that accounts for the energy loss in the meniscus movement along with the sliding contact. Occurrence of the water-meniscus-generated friction is experimentally proved by atomic force microscopy measurements of the tip-sample friction force at minimum possible external load (before pull-off). A qualitative explanation for the observed dependence of the friction force on air humidity and solid surface wettability is proposed.

  18. Alveolar Capillary Dysplasia

    PubMed Central

    Stankiewicz, Pawel; Steinhorn, Robin H.

    2011-01-01

    Alveolar capillary dysplasia with misalignment of the pulmonary veins (ACD/MPV) is a rare, fatal developmental lung disorder of neonates and infants. This review aims to address recent findings in the etiology and genetics of ACD/MPV and to raise awareness of this poorly known disease, which may also present as milder, unclassified forms. Successively discussed are what is known about the epidemiology, pathogenesis, pathophysiology, diagnostic indicators and approaches, genetic testing, treatment, and cases of delayed onset. The review concludes with suggestions for future directions to answer the many unknowns about this disorder. PMID:21471096

  19. 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.

  20. 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

  1. 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.

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

    SciTech Connect

    Robin, M.; Rosenberg, E.; Fassi-Fihri, O.

    1995-03-01

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

  3. Tapered capillary optics

    DOEpatents

    Hirsch, Gregory

    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.

  4. Capillary Electrophoresis in Metabolomics.

    PubMed

    Maier, Tanja Verena; Schmitt-Kopplin, Philippe

    2016-01-01

    Metabolomics is an analytical toolbox to describe (all) low-molecular-weight compounds in a biological system, as cells, tissues, urine, and feces, as well as in serum and plasma. To analyze such complex biological samples, high requirements on the analytical technique are needed due to the high variation in compound physico-chemistry (cholesterol derivatives, amino acids, fatty acids as SCFA, MCFA, or LCFA, or pathway-related metabolites belonging to each individual organism) and concentration dynamic range. All main separation techniques (LC-MS, GC-MS) are applied in routine to metabolomics hyphenated or not to mass spectrometry, and capillary electrophoresis is a powerful high-resolving technique but still underused in this field of complex samples. Metabolomics can be performed in the non-targeted way to gain an overview on metabolite profiles in biological samples. Targeted metabolomics is applied to analyze quantitatively pre-selected metabolites. This chapter reviews the use of capillary electrophoresis in the field of metabolomics and exemplifies solutions in metabolite profiling and analysis in urine and plasma. PMID:27645748

  5. On Capillary Rise and Nucleation

    ERIC Educational Resources Information Center

    Prasad, R.

    2008-01-01

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

  6. Capillary optics for radiation focusing

    SciTech Connect

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

    1996-11-01

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

  7. 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.

  8. 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.

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

    PubMed

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

    2013-06-11

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

  10. Effect of Surface-Active Pseudomonas spp. on Leaf Wettability

    PubMed Central

    Bunster, Lillian; Fokkema, Nyckle J.; Schippers, Bob

    1989-01-01

    Different strains of Pseudomonas putida and P. fluorescens isolated from the rhizosphere and phyllosphere were tested for surface activity in droplet cultures on polystyrene. Droplets of 6 of the 12 wild types tested spread over the surface during incubation, and these strains were considered surface active; strains not showing this reaction were considered non-surface active. Similar reactions were observed on pieces of wheat leaves. Supernatants from centrifuged broth cultures behaved like droplets of suspensions in broth; exposure to 100°C destroyed the activity. Average contact angles of the supernatants of surface-active and non-surface-active strains on polystyrene were 24° and 72°, respectively. The minimal surface tension of supernatants of the surface-active strains was about 46 mN/m, whereas that of the non-surface-active strains was 64 mN/m (estimations from Zisman plots). After 6 days of incubation, wheat flag leaves sprayed with a dilute suspension of a surface-active strain of P. putida (WCS 358RR) showed a significant increase in leaf wettability, which was determined by contact angle measurements. Increasing the initial concentration of bacteria and the amount of nutrients in the inoculum sprayed on leaves reduced the contact angles from 138° on leaves treated with antibiotics (control) to 43° on leaves treated with surface-active bacteria. A closely related strain with no surface activity on polystyrene did not affect leaf wettability, although it was present in densities similar to those of the surface-active strain. Nutrients alone could occasionally also increase leaf wettability, apparently by stimulating naturally occurring surface-active bacteria. When estimating densities of Pseudomonas spp. underneath droplets with low contact angles, it appeared that populations on leaves treated with a surface-active strain could vary from about 104 to 106 CFU cm−2, suggesting that the surface effect may be prolonged after a decline of the

  11. Underwater Sliding Properties: Effect of Slider Shape and Surface Wettability

    NASA Astrophysics Data System (ADS)

    Kirveslahti, A.; Mielonen, K.; Ikonen, K.; Cui, W.; Suvanto, M.; Pakkanen, T. A.

    2016-04-01

    A dynamic test method for the measurement of the underwater sliding properties of model boats has been developed. Surface-modified model boats were examined to assess how the surface wettability properties affect sliding. Along with the surface properties, the influence of the boat shape was considered. We studied various coatings in the contact angle range of 3-162∘ with two model boat shapes. The hydrophobicity of the surfaces influenced the sliding speed of the model boat depending on the boat shape. The method is applicable to study sliding properties of model boats with different surfaces in variable flow conditions.

  12. The wettability of selected organic soils in Poland

    NASA Astrophysics Data System (ADS)

    Całka, A.; Hajnos, M.

    2009-04-01

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

  13. 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.

  14. 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.

  15. Benign sinonasal capillary haemangioma

    PubMed Central

    Stubbs, Darren; Poulios, Aristotelis; Khalil, Hisham

    2014-01-01

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

  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.; Chang, Huan-Tsang; Fung, Eliza 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.

  18. 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.

  19. A Microfluidic Device for Mixing of Capillary-Driven Liquids

    NASA Astrophysics Data System (ADS)

    Hosokawa, Kazuo; Maeda, Mizuo

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

  20. 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.

  1. 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.

  2. Applications of capillary optical fibers

    NASA Astrophysics Data System (ADS)

    Romaniuk, Ryszard

    2006-10-01

    The paper updates and summarizes contemporary applications of capillary optical fibers. Some of these applications are straight consequence of the classical capillary properties and capillary devices like: rheometry, electrophoresis, column chromatography (gas and liquid). Some new applications are tightly connected with co-propagation (or counter-propagation) of micro-mass together with optical wave - evanescent or of considerable intensity. In the first case, the optical wave is propagated in a narrow (more and more frequently single-mode) optical ring core adjacent to the capillary hole. The optical propagation is purely refractive. In the second case, the intensity maximum of optical wave is on the capillary long axis, i.e. in the center of the hole. The optical propagation is purely photonic, i.e. in a Bragg waveguide (one dimensional photonic band-gap). The capillary hole is filled with vacuum or with propagated matter (gas, liquid, single atoms, continuous particle arrangement). Optical capillaries, filamentary and embedded, are turning to a fundamental component of nano- and micro-MOEMS.

  3. Instability of the capillary bridge

    NASA Astrophysics Data System (ADS)

    Pare, Gounseti; Hoepffner, Jerome

    2014-11-01

    Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

  4. Wettability of pristine and alkyl-functionalized graphane.

    PubMed

    Vanzo, Davide; Bratko, Dusan; Luzar, Alenka

    2012-07-21

    Graphane is a hydrogenated form of graphene with high bandgap and planar structure insensitive to a broad range of chemical substitutions. We describe an atomistic simulation approach to predict wetting properties of this new material. We determine the contact angle to be 73°. The lower hydrophobicity compared to graphene is explained by the increased planar density of carbon atoms while we demonstrate that the presence of partial charges on carbon and hydrogen atoms plays only a minor role. We further examine the effects of graphane functionalization by alkyl groups of increasing chain lengths. The gradual increase in contact angle with chain length offers a precise control of surface wettability. A saturated contact angle of 114° is reached in butylated form. We find the saturation of contact angle with respect to the length of the functional groups to coincide with the loss of water's ability to penetrate the n-alkyl molecular brush and interact with carbon atoms of the underlying lattice. Since no experimental data have yet become available, our modeling results provide the first estimate of the wettability of graphane. The results also show how its alkyl functionalization provides the basis for a variety of chemical modifications to tune hydrophilicity while preserving the planar geometry of the substrate. PMID:22830724

  5. Wettability of pristine and alkyl-functionalized graphane

    NASA Astrophysics Data System (ADS)

    Vanzo, Davide; Bratko, Dusan; Luzar, Alenka

    2012-07-01

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

  6. 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 (α, 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 |α0 - 0.5|, where α0 is the transfer ratio in the quasi-static regime, and α0 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 α for a fast transfer system.

  7. Controllable wettability and morphology of electrodeposited surfaces on zinc substrates

    NASA Astrophysics Data System (ADS)

    Zhang, Binyan; Lu, Shixiang; Xu, Wenguo; Cheng, Yuanyuan

    2016-01-01

    Superhydrophobic surfaces combining hierarchical micro/nanostructures were fabricated on zinc substrates by etching in hydrochloric acid solution, electrodeposition of ZnO coatings and subsequent thermal annealing. The optimal coatings were electrodeposited at -1.25 V for 900 s on the etched zinc substrates and then annealed at 200 °C for 60 min, which could achieve a maximum water contact angle of 170 ± 2° and an ultra-low sliding angle of approximately 0°. By conducting SEM and water CA analysis, we found that the morphology and wettability of prepared samples were controllable by the fabrication process. Interestingly, even without any additional modification, the samples prepared under different electrodeposition conditions (including Zn(CH3COO)2 concentration from 5 mM to 40 mM and deposition time from 300 s to 1500 s) exhibited superhydrophobic character. The influences of the Zn(CH3COO)2 concentration, deposition time, annealing temperature and annealing time on the wetting behaviors were also discussed in detail. Such superhydrophobic surfaces possess long-term stability, and good corrosion resistance as well as self-cleaning ability. In addition, the anti-icing properties of the ZnO films were investigated. These surfaces could be rapidly and reversibly switched between superhydrophobicity and superhydrophilicity by alternating UV illumination and dark storage or thermal annealing. The intelligent switchable surfaces with controllable wettability and morphology offer possibilities for chemical, biological, electronic and microfluidic applications.

  8. 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.

  9. 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.

  10. Morphology modulating the wettability of a diamond film.

    PubMed

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

    2014-10-28

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

  11. Effects of aluminium surface morphology and chemical modification on wettability

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  12. Study of the wettability of ZnO nanofilms

    NASA Astrophysics Data System (ADS)

    Subedi, Deepak Prasad; Madhup, Dinesh Kumar; Sharma, Ashish; Joshi, Ujjwal Man; Huczko, Andrzej

    2012-04-01

    Al-doped and un-doped ZnO thin films deposited on quartz substrates by the nebulized spray pyrolysis method were studied to investigate the wettability of the surface. The main objective of the present study was to investigate the wettability of ZnO thin film by changing the concentration of Al doping. Microstructure and water contact angles of the films were measured by scanning electron microscopy (SEM) and using a contact angle goniometer. SEM studies revealed that the grain size within the film increases with the doping concentration. The contact angles were studied to see the effect of aluminum doping on the hydrophilicity of the film. ZnO films were found to be hydrophobic in nature. A good correlation was observed between the SEM micrographs and contact angle results. The nature of the film was found to change from being hydrophobic to hydrophilic after the treatment in low-pressure DC glow discharge plasma, which, however, was reversible with the storage time.

  13. Improved Surface wettability of polyurethane films by Ultraviolet Ozone treatment

    SciTech Connect

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

    2010-07-01

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

  14. Wettability of AlSi5Mg on Spodumene

    NASA Astrophysics Data System (ADS)

    Fankhänel, Beate; Stelter, Michael; Voigt, Claudia; Aneziris, Christos G.

    2015-02-01

    The development of new filters for the aluminum industry requires investigations on the wettability of aluminum and its alloys on novel filter materials. The requested filter effects require not only an adequate wetting but also information about the interaction between the filter material and the metal. In the present work the wettability of an AlSi5Mg alloy on spodumene (LiAl[Si2O6]) containing substrates is investigated using the sessile drop technique. These measurements were carried out at 1223 K (950 °C) under vacuum. The spodumene-based substrates showed a completely different wetting behavior compared with an alumina substrate. The contact angel reduced more quickly and leveled out at a lower value (75 ± 2 deg) than in case of a pure alumina substrate (90 ± 1 deg). The reason for this behavior is a reaction between the LiAl(Si2O6) and the alloy droplet which supported deoxidation and formed a silica-rich reaction layer at the droplet/substrate interface.

  15. Integrated multiplexed capillary electrophoresis system

    DOEpatents

    Yeung, Edward S.; Tan, Hongdong

    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.

  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

  17. 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.

  18. A feasible electrochemical method for tuning coatings wettability from superhydrophilicity to superhydrophobicity

    NASA Astrophysics Data System (ADS)

    Xu, Lianyi; Wei, Donglai; Chen, Yunxia; Li, Rongbin

    2016-11-01

    A feasible electrochemical method for controlling arbitrarily the surface wettability between superhydrophilicity and superhydrophobicity was presented in details. A series of composited polythiophene films (PL-PEDOT) with wettability from superhydrophilicity to superhydrophobicity were readily fabricated by tuning precisely the electrodeposition charge (EC) of overlying hydrophobic poly(2,2‧-bithiophene) (PLTH) moieties on the underlying poly(3,4-ethylenedioxythiophene) (PEDOT) moieties. The various wettability of the resulting PL-PEDOT film could be attributed to the combination of the conducting and porous nanostructure of PEDOT films and the flexible electrodeposition strategy. The wettability change of PL-PEDOT films is also companied by the changes in their spectral colors. This electrochemical method could present a feasible technique for the preparation of various wettability surfaces in practical applications.

  19. Analysis of Capillary Rise in Asymmetric Branch-Like Capillary

    NASA Astrophysics Data System (ADS)

    Li, Caoxiong; Shen, Yinghao; Ge, Hongkui; Yang, Zhihui; Su, Shuai; Ren, Kai; Huang, Heyu

    2016-05-01

    Transport in porous media is common in nature, attracting many attentions for a long time. Tree-like network model is often used as a simplification for porous space, expressing the complexity of pore spaces instead of capillary bundle. To investigate spontaneous imbibition characteristics in this network, a dynamic asymmetric branch-like capillary model is used to represent basic network structure, using fractal method to represent tortuosity. This work investigates the influence of parameters on imbibition process in the branch-like capillary model. An analytical equation for the imbibition mass versus time is derived. Parameters from capillary structures to liquid properties are taken into account and analyzed based on the numerical solution of the equation. It is found that the imbibition process in asymmetric branch-like capillary model can be recognized by four sections and brunching tubes are positive for imbibition process. Concomitantly, meniscus arrest event is simulated and discussed. Moreover, the influence of parameters on imbibition process is discussed. These parameters can be classified as static and dynamic. Static parameters mainly change the capillary force, which are related to the ultimate imbibition mass or imbibition ability, while dynamic parameters mainly have influence on resistance of flowing fluid, which are related to the imbibition speed in the imbibition process.

  20. Surface tension drawing of liquid from microplate capillary wells.

    PubMed

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

    2012-01-01

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

  1. 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.

  2. Liposome behavior in capillary electrophoresis.

    PubMed

    Roberts, M A; Locascio-Brown, L; Maccrehan, W A; Durst, R A

    1996-10-01

    The behavior of liposomes in capillary electrophoresis is studied for the purpose of developing a potential method for characterizing liposomes prepared for use in industrial and analytical applications. This study characterizes the electrophoretic behavior of liposomes under various conditions to provide information about electrophoretic mobility and liposome-capillary surface interactions. The results of this method are compared with the results obtained using traditional laser light-scattering methods to obtain size information about liposome preparations. Additionally, reactions of liposomes and the surfactant n-octyl-β-d-glucopyranoside are performed off-line in bulk solution experiments and on-line in the capillary. Automated delivery of lysis agents by multiple electrokinetic injections is demonstrated as a general method for inducing on-capillary reactions between liposomes and other reagents. Furthermore, some preliminary evidence on the use of liposomes as a hydrophobic partitioning medium for analytical separations is presented.

  3. Capillary Electrophoresis in Wine Science.

    PubMed

    Coelho, Christian; Bagala, Franck; Gougeon, Régis D; Schmitt-Kopplin, Philippe

    2016-01-01

    Capillary electrophoresis appeared to be a powerful and reliable technique to analyze the diversity of wine compounds. Wine presents a great variety of natural chemicals coming from the grape berry extraction and the fermentation processes. The first and more abundant after water, ethanol has been quantified in wines via capillary electrophoresis. Other families like organic acids, neutral and acid sugars, polyphenols, amines, thiols, vitamins, and soluble proteins are electrophoretically separated from the complex matrix.Here, we will focus on the different methodologies that have been employed to conduct properly capillary electrophoresis in wine analysis.Two examples informing on wine chemistry obtained by capillary electrophoresis will be detailed. They concern polyphenol analysis and protein profiling. The first category is a well-developed quantitative approach important for the quality and the antioxidant properties conferred to wine. The second aspect involves more research aspects dealing with microbiota infections in the vineyard or in the grape as well as enological practices. PMID:27645750

  4. 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)

  5. Capillary electrophoresis electrospray ionization mass spectrometry interface

    DOEpatents

    Smith, Richard D.; Severs, Joanne C.

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  7. Dynamic wettability properties of a soft contact lens hydrogel.

    PubMed

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

    2005-01-15

    The wettability of poly[2-hydroxyethyl methacrylate-co-methacrylic acid] (pHEMA-MAA) soft contact lenses was investigated in the absence and presence of block copolymer surfactants and lysozyme using the sessile drop method. The advancing dynamic contact angles (Thetaw/a) values are reported for water as a function of sequential wetting and drying cycles. The Thetaw/a values for the pHEMA-MAA in the absence of surfactant and lysozyme increased from approximately 20 degrees to 100 degrees as the number of cycles increased from two to ten, and they were independent of the pHEMA-MAA bulk water content. The change from the highly hydrophilic to hydrophobic pHEMA-MAA surface could not be reversed using the sequential wetting and drying cycles even under repeated exposures to saline solution. The effect of block copolymer surfactants with different molecular weights (MW) and hydrophilic-lipophilic balance (HLB) values on the pHEMA-MAA wettability were also studied. Low Theta(w/a) values were observed for pHEMA-MAA hydrogels that were treated with T1304 (MW 10500, HLB 14) and T904 (MW 6700, HLB 15). The surface tension data indicated that these surfactants were incompletely desorbed from the pHEMA-MAA and that the rate of desorption was slow in the timescale of the cycling experiments. Comparatively, poor wettability was observed for pHEMA-MAA surfaces presoaked in T304 (MW 1650, HLB 16) and T1107 (MW 15000, HLB 24) as Thetaw/a values greater than 90 degrees were measured for these surfactants. The surface tension data indicated that the rate of desorption of T304 and T1107 from the pHEMA-MAA was rapid and that they had a low affinity to the pHEMA-MAA. High contact angles were observed for the pHEMA-MAA hydrogels treated with lysozyme and also for the T1107 presoaked pHEMA-MAA that was also treated with lysozyme. Zero wetting angles throughout the sequential cycling were observed for the T1304 pre-treated pHEMA-MAA that had been treated with lysozyme. These results

  8. 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

  9. 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.

  10. 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 “θ/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.

  11. 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.

  12. Adjustable wettability of paperboard by liquid flame spray nanoparticle deposition

    NASA Astrophysics Data System (ADS)

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

    2011-01-01

    Liquid flame spray process (LFS) was used for depositing TiO x and SiO x nanoparticles on paperboard to control wetting properties of the surface. By the LFS process it is possible to create either superhydrophobic or superhydrophilic surfaces. Changes in the wettability are related to structural properties of the surface, which were characterized using scanning electron microscope (SEM) and atomic force microscope (AFM). The surface properties can be ascribed as a correlation between wetting properties of the paperboard and the surface texture created by nanoparticles. Surfaces can be produced inline in a one step roll-to-roll process without need for additional modifications. Furthermore, functional surfaces with adjustable hydrophilicity or hydrophobicity can be fabricated simply by choosing appropriate liquid precursors.

  13. Light-driven wettability changes on a photoresponsive electrospun mat.

    PubMed

    Chen, Menglin; Besenbacher, Flemming

    2011-02-22

    Novel nanofibers of biodegradable polycaprolactone (PCL) modified with light-responsive azobenzene were prepared by electrospinning upon a facile one-pot reaction. The surface chemistry of the nanofibers was probed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Both XPS and ToF-SIMS spectra proved the successful conjugation of azobenzene with PCL. ToF-SIMS not only enabled chemical mapping but also provided morphology information, supplementary to scanning electron microscopy (SEM). The large, reversible, and light-responsive wettability changes of the functional fibrous surfaces were further demonstrated using UV-vis spectroscopy and contact angle (CA) measurements.

  14. Effect of wettability alteration on long-term behavior of fluids in subsurface

    NASA Astrophysics Data System (ADS)

    Bandara, Uditha C.; Palmer, Bruce J.; Tartakovsky, Alexandre M.

    2016-04-01

    Wettability is an important factor affecting fluid behavior in the subsurface, including oil, gas, and supercritical hbox {CO}_2 in deep geological reservoirs. For example, hbox {CO}_2 is generally assumed to behave as a non-wetting fluid, which favors safe storage. However, because of chemical heterogeneity of the reservoirs, mixed wettability conditions can exist. Furthermore, recent experiments suggest that with time, the wettability of super-critical hbox {CO}_2 may change from non-wetting to partially wetting due to changes in electrostatic interactions. These changes are caused by chemical reactions between dissolved hbox {CO}_2 and its environment. To date, the effect of wettability alteration and mixed wettability on the long-term fate of injected hbox {CO}_2 has not well been studied. Here, we use the multiphase pairwise force smoothed particle hydrodynamics model to study complex pore-scale processes involved in geological hbox {CO}_2 sequestration, including the effect of spatial and temporal wettability variations on long-term distribution of hbox {CO}_2 in porous media. Results reveal that in the absence of dissolution of supercritical hbox {CO}_2 and precipitation of carbonate minerals (mineral trapping), the amount of trapped supercritical hbox {CO}_2 significantly decreases as the wettability of the porous media changes from brine-wet to partial-wet or hbox {CO}_2-wet.

  15. Effects of wettability and interfacial nanobubbles on flow through structured nanochannels: an investigation of molecular dynamics

    NASA Astrophysics Data System (ADS)

    Yen, Tsu-Hsu

    2015-12-01

    Solid-fluid boundary conditions are strongly influenced by a number of factors, including the intrinsic properties of the solid/fluid materials, surface roughness, wettability, and the presence of interfacial nanobubbles (INBs). The interconnected nature of these factors means that they should be considered jointly. This paper employs molecular dynamics (MD) simulation in a series of studies aimed at elucidating the influence of wettability in boundary behaviour and the accumulation of interfacial gas. Specifically, we examined the relationship between effective slip length, the morphology of nanobubbles, and wettability. Two methods were employed for the promotion of hydrophobicity between two structured substrates with similar intrinsic contact angles. We also compared anisotropic and isotropic atomic arrangements in the form of graphite and Si(100), respectively. A physical method was employed to deal with variations in surface roughness, whereas a chemical method was used to adjust the wall-fluid interaction energy (ɛwf). We first compared the characteristic properties of wettability, including contact angle and fluid density within the cavity. We then investigated the means by which variations in solid-fluid interfacial wettability affect interfacial gas molecules. Our results reveal that the morphology of INB on a patterned substrate is determined by wettability as well as the methods employed for the promotion of hydrophobicity. The present study also illustrates the means by which the multiple effects of the atomic arrangement of solids, surface roughness, wettability and INB influence effective slip length.

  16. Modelling the effect of wettability distributions on oil recovery from microporous carbonate reservoirs

    NASA Astrophysics Data System (ADS)

    Kallel, W.; van Dijke, M. I. J.; Sorbie, K. S.; Wood, R.; Jiang, Z.; Harland, S.

    2016-09-01

    Carbonate-hosted hydrocarbon reservoirs are known to be weakly- to moderately oil-wet, but the pore-scale wettability distribution is poorly understood. Moreover, micropores, which often dominate in carbonate reservoirs, are usually assumed to be water-wet and their role in multi-phase flow is neglected. Modelling the wettability of carbonates using pore network models is challenging, because of our inability to attribute appropriate chemical characteristics to the pore surfaces and over-simplification of the pore shapes. Here, we implement a qualitatively plausible wettability alteration scenario in a two-phase flow network model that captures a diversity of pore shapes. The model qualitatively reproduces patterns of wettability alteration recently observed in microporous carbonates via high-resolution imaging. To assess the combined importance of pore-space structure and wettability on petrophysical properties, we consider a homogeneous Berea sandstone network and a heterogeneous microporous carbonate network, whose disconnected coarse-scale pores are connected through a sub-network of fine-scale pores. Results demonstrate that wettability effects are significantly more profound in the carbonate network, as the wettability state of the micropores controls the oil recovery.

  17. Enhancing Liquid Micro-volume Mixing with Wettability-Patterned Surfaces

    NASA Astrophysics Data System (ADS)

    Morrissette, Jared; Sinha Mahapatraa, Pallab; Ganguly, Ranjan; Megaridis, Constantine; Uic-Mnftl Team

    2015-11-01

    Self-driven surface micromixers (SDSM) based on patterned wettability technology provide an elegant solution for low-cost point-of-care (POC) devices and lab-on-a-chip (LOC) applications. Our SDSMs are fabricated by strategically patterning three wettable wedge-shaped tracks onto a non-wettable surface. Current state-of-the-art micromixers require energy, however, our SDSMs utilize the inherent surface energy of liquids, coupled with wettability contrast to efficiently mix small amounts of liquids (e.g. droplets). Transport and mixing of the SDSMs is accomplished by means of Laplace pressure-driven flow and several mixing approaches, such as splitting-recombining, stretching-folding, and transversal vortices. Mixing is initiated when separate liquid micro-volumes are transported along respective, juxtaposed wettable tracks. As the liquid micro-volumes coalesce, subsequent mixing occurs during transport of the combined volume over a third separate wettable track that also features a non-wettable ``island.'' The two-dimensional island disrupts the flow of liquids, in a similar manner a three-dimensional obstacle would, thus generating the aforementioned mixing enhancement. Several SDSMs, each having different island geometries, were investigated, giving rise to a greater understanding of efficient mixing on surfaces. The study offers a design basis for developing a low-cost surface microfluidic mixing device on various substrates.

  18. Local wettability tuning with laser ablation redeposits on PDMS

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  19. 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.

  20. Effects of simulated storage on the solder wettability of inhibited substrates

    SciTech Connect

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

    1992-01-01

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

  1. Effects of simulated storage on the solder wettability of inhibited substrates

    SciTech Connect

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

    1992-12-01

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

  2. Surface wettability enhancement of silicone hydrogel lenses by processing with polar plastic molds.

    PubMed

    Lai, Y C; Friends, G D

    1997-06-01

    In the quest for hydrogel contact lenses with improved extended wear capability, the use of siloxane moieties in the lens materials was investigated. However, the introduction of hydrophobic siloxane groups gave rise to wettability and lipidlike deposit problems. It was found that when polysiloxane-based compositions for hydrogels were processed with polar plastic molds, such as those fabricated from an acrylonitrile-based polymer, the hydrogel lenses fabricated were wettable, with minimized lipidlike deposits. These findings were supported by the wettability of silicone hydrogel films, silicon, and nitrogen element contents near lens surfaces, as well as the results from clinical assessment of silicone hydrogel lenses. PMID:9138069

  3. Synthesis, characterization and surface wettability study of polypyrrole films: Effect of applied constant current density

    NASA Astrophysics Data System (ADS)

    Thombare, J. V.; Lohar, G. M.; Shinde, S. K.; Dhasade, S. S.; Rath, M. C.; Fulari, V. J.

    2015-03-01

    Polypyrrole thin films were prepared by galvanostatic mode of electrodeposition. The applied constant current density changes structural, optical and surface wettability properties of polypyrrole thin films. The prepared films were characterized for structural, optical and surface wettability study. Fourier transform infrared spectroscopy shows the benzoid and qunoid like structures in polypyrrole films. The UV-Visible absorption study shows that the optical density varies with the applied deposition current density. The band gap energy calculated from the Tauc's plot was found to be 2.25 eV and shows the film is in semiconductor nature. The surface wettability study confirms hydrophilic nature of polypyrrole films. [Figure not available: see fulltext.

  4. Biocompatible patterning of proteins on wettability gradient surface by thermo-transfer printing.

    PubMed

    Kim, Sungho; Ryu, Yong-Sang; Suh, Jeng-Hun; Keum, Chang-Min; Sohn, Youngjoo; Lee, Sin-Doo

    2014-08-01

    We develop a simple and biocompatible method of patterning proteins on a wettability gradient surface by thermo-transfer printing. The wettability gradient is produced on a poly(dimethylsiloxane) (PDMS)-modified glass substrate through the temperature gradient during thermo-transfer printing. The water contact angle on the PDMS-modified surface is found to gradually increase along the direction of the temperature gradient from a low to a high temperature region. Based on the wettability gradient, the gradual change in the adsorption and immobilization of proteins (cholera toxin B subunit) is achieved in a microfluidic cell with the PDMS-modified surface. PMID:25936059

  5. Structure-function studies of blood and air capillaries in chicken lung using 3D electron microscopy.

    PubMed

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

    2010-02-28

    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

  6. Capillary instability of jets

    NASA Astrophysics Data System (ADS)

    Chauhan, Anuj

    This thesis studies the capillary instability of a compound jet. A compound jet comprises an inner core of a primary fluid surrounded by an annulus of an immiscible secondary fluid. The compound jet is unstable due to capillarity. A compound jet finds applications in a variety of fields, such as, ink jet printing, particle sorting, extrusion, molding, particle production etc. In some of these applications such as molding, the disturbances that could cause the jet breakup start as periodic spatial disturbances of Fourier wave number k and grow in time. This is the temporal instability. In some other applications, such as, ink-jet printing, the disturbances initiate at the edge of the nozzle from which the jet issues out. These disturbances grow in space. This is the spatial instability. At small velocities, even if the initial disturbances are periodic in time, they grow exponentially in time. This is the absolute instability. We perform the temporal, spatial and the absolute stability analysis of an inviscid compound jet in a unified framework using the theory of transforms. Further, we solve the temporal instability problem for a viscous jet to understand the effect of viscosity on breakup dynamics. In the temporal analysis, we show that each interface of the compound jet contributes one mode to the instability. The modes contributed by the inner and outer interfaces grow for waves longer than the inner and the outer circumference of the undisturbed jet, respectively. The inner interface mode has a higher growth rate and hence dominates the breakup. The two interfaces grow exactly in phase in this mode and hence it is refereed to as the stretching mode. The other mode is the squeezing mode because the two interfaces grow exactly out of phase. The same two modes are also present in the spatial analysis. At high Weber numbers the predictions of the spatial theory reduce to those of the temporal theory because the waves simply convect with the jet velocity and there

  7. 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.

  8. 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.

  9. 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.

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

    PubMed

    Desai, Nikhil; Ghosh, Uddipta; Chakraborty, Suman

    2014-06-01

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

  11. Decay of capillary wave turbulence.

    PubMed

    Deike, Luc; Berhanu, Michael; Falcon, Eric

    2012-06-01

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

  12. 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.

  13. Ceramic Wick For Capillary-Pumped Heat Pipe

    NASA Technical Reports Server (NTRS)

    Seidenberg, Benjamin; Swanson, Theodore

    1989-01-01

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

  14. [Application hemostatic drug in capillary-parenchymatous bleeding].

    PubMed

    Belozerskaia, G G; Makarov, V A; Aboiants, R K; Istranov, L P; Malykhina, L S; Zhidkov, E A

    2004-01-01

    Specific activity of a new hemostatic drug thrombocol was studied in experiments. Laboratory rabbits were used for management of experimental capillary-parenchymatous hemorrhage. The action of thrombocol was compared with hemostatic effect of other drugs: carbocol, combutek-2, super-4 (USA), collastipt (Germany), collagen sponge (Germany). It was found that thrombocol was highly hygroscopic, showed good adhesion to wounded surface, high plasticity and better hemostatic effect compared with other collagen-containing drugs.

  15. Three-Phase Capillary Pressure, Hysteresis and Trapping in a Porous Glass-Bead Column

    NASA Astrophysics Data System (ADS)

    Andersson, L.; Schlüter, S.; Li, T.; Brown, K. I.; Helland, J. O.; Wildenschild, D.

    2015-12-01

    Enhanced oil recovery (EOR) strategies employing water-alternate-gas (WAG) injections may improve oil mobility and production recovery. WAG injections for EOR create regions in the reservoir with simultaneous flow of oil, water and air dominated by capillary and gravity forces. As a result of the dynamics in the transition zones, the invading fluid may snap off compartments of the displaced fluid which could then be trapped in the pore space, contributing to the hysteresis of the three-phase capillary pressure curves. Three-phase capillary pressure curves are needed to model the three-phase transition zone movements in the reservoir. In reservoir simulation models, the common practice has been to implement three-phase capillary pressure curves based on two-phase gas-oil and oil-water capillary pressure data. However, experimental and modelling studies of three-phase fluid distributions at the pore scale have shown that this procedure is not always valid; three-phase capillary pressure curves exhibit hysteresis and depend on the saturation history of the three phases which cannot be derived from two-phase capillary pressure curves. We have developed three-phase experiments that provide capillary pressures and 3D-image data of fluid distributions in the entire saturation space of oil, water and air in water-wet porous glass-bead columns; a time-consuming and technically challenging exercise. The 3D data with a resolution of 6.38 μm 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. In particular, we discuss how three-phase pore-scale mechanisms, such as oil layer existence and multiple displacement events, affect the mobility and trapping of oil in the porous medium. We also show that wettability-alterations of the porous medium in contact with the three-phase fluid system and exposure to x-rays can be avoided by using iodine

  16. Atomic force microscopy characterization of the surface wettability of natural fibres

    NASA Astrophysics Data System (ADS)

    Pietak, Alexis; Korte, Sandra; Tan, Emelyn; Downard, Alison; Staiger, Mark P.

    2007-01-01

    Natural fibres represent a readily available source of ecologically friendly and inexpensive reinforcement in composites with degradable thermoplastics, however chemical treatments of fibres are required to prepare feasible composites. It is desirable to characterize the surface wettability of fibres after chemical treatment as the polarity of cellulose-based fibres influences compatibility with a polymer matrix. Assessment of the surface wettability of natural fibres using conventional methods presents a challenge as the surfaces are morphologically and chemically heterogeneous, rough, and can be strongly wicking. In this work it is shown that under atmospheric conditions the adhesion force between an atomic force microscopy (AFM) tip and the fibre surface can estimate the water contact angle and surface wettability of the fibre. AFM adhesion force measurements are suitable for the more difficult surfaces of natural fibres and in addition allow for correlations between microstructural features and surface wettability characteristics.

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

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Wu, L.; Wu, Q. J.

    2000-05-01

    Soil water-repellency is an increasingly important consideration in hydrology. In this paper, we relate the degree of soil water-repellency and wettability to the critical water-entry value of a soil. A water-ponding method was used for simple measurement of water-entry value in repellent soils. A tension-pressure infiltrometer method was demonstrated for measuring water-entry value in both repellent and wettable soils. The measurement techniques were used to detect a sudden breakdown of repellency under a sufficiently high water pressure. Experimental results have proven that the water-entry value, in terms of soil water potential, is positive in repellent soils, and negative in wettable soils or soil conditions. The water-entry value is shown to be an easily measured indicator of repellency or wettability that provide an assessment of hydraulic effects of soil physical, chemical and biological properties.

  18. Revised Capillary Breakup Rheometer Method

    NASA Astrophysics Data System (ADS)

    Lu, Louise; Schultz, William; Solomon, Michael

    2014-11-01

    Rather than integrate the one-dimensional equation of motion for a capillary breakup rheometer, we take the axial derivative of that equation. This avoids the determination of the axial force with all of its complications and correction factors. The resulting evolutionary equation that involves either two or four derivatives of the capillary radius as a function of the axial coordinate determines the ratio of elongational viscosity to surface tension coefficient. We examine several silicone and olive oils to show the accuracy of the method for Newtonian fluids. We will discuss our surface tension measurement techniques and briefly describe measurements of viscoelastic materials, including saliva.

  19. Conformation-sensitive capillary electrophoresis.

    PubMed

    Ashton, Emma Jane

    2011-01-01

    Conformation-sensitive capillary electrophoresis (CSCE) is a rapid, high-throughput screening method that can be applied to any region of a genome for detection of sequence variants. Slab gel-based conformation-sensitive gel electrophoresis was first described by Ganguly et al., and the transfer from slab gels to capillaries for higher throughput was reported by Rozycka et al. CSCE is based on the principle that DNA homoduplexes and heteroduplexes migrate at different rates during electrophoresis under mildly denaturing conditions. Fragments showing an altered peak morphology compared to the wild type are then sequenced to determine the precise nature of the sequence variant detected.

  20. 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.

  1. Capillary interactions in Pickering emulsions

    NASA Astrophysics Data System (ADS)

    Guzowski, J.; Tasinkevych, M.; Dietrich, S.

    2011-09-01

    The effective capillary interaction potentials for small colloidal particles trapped at the surface of liquid droplets are calculated analytically. Pair potentials between capillary monopoles and dipoles, corresponding to particles floating on a droplet with a fixed center of mass and subjected to external forces and torques, respectively, exhibit a repulsion at large angular separations and an attraction at smaller separations, with the latter resembling the typical behavior for flat interfaces. This change of character is not observed for quadrupoles, corresponding to free particles on a mechanically isolated droplet. The analytical results are compared with the numerical minimization of the surface free energy of the droplet in the presence of spherical or ellipsoidal particles.

  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

  3. Investigation of energy dissipation due to contact angle hysteresis in capillary effect

    NASA Astrophysics Data System (ADS)

    Athukorallage, Bhagya; Iyer, Ram

    2016-06-01

    Capillary action or Capillarity is the ability of a liquid to flow in narrow spaces without the assistance of, and in opposition to, external forces like gravity. Three effects contribute to capillary action, namely, adhesion of the liquid to the walls of the confining solid; meniscus formation; and low Reynolds number fluid flow. We investigate the dissipation of energy during one cycle of capillary action, when the liquid volume inside a capillary tube first increases and subsequently decreases while assuming quasi-static motion. The quasi-static assumption allows us to focus on the wetting phenomenon of the solid wall by the liquid and the formation of the meniscus. It is well known that the motion of a liquid on an non-ideal surface involves the expenditure of energy due to contact angle hysteresis. In this paper, we derive the equations for the menisci and the flow rules for the change of the contact angles for a liquid column in a capillary tube at a constant temperature and volume by minimizing the Helmholtz free energy using calculus of variations. We describe the numerical solution of these equations and present results from computations for the case of a capillary tube with 1 mm diameter.

  4. 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.

  5. 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

  6. 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.

  7. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John 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.

  8. 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.

  9. Multiplexed fluorescence detector system for capillary electrophoresis

    DOEpatents

    Yeung, Edward S.; Taylor, John 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.

  10. 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.

  11. 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…

  12. 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

    2015-01-01

    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, α-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.

  13. 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

    2015-01-01

    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, α-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

  14. Capillary blood viscosity in microcirculation.

    PubMed

    Cortinovis, A; Crippa, A; Cavalli, R; Corti, M; Cattaneo, L

    2006-01-01

    As known, at the arteriolar level there is the highest resistance to the flow due to the section and to the velocity with an average pressure fall of 50 mmHg (from 85 to 35 mmHg). This resistance is expressed in sec(-1) by the ratio W/2r. This ratio is very high with an average value of 332 sec(-1) and viscosity at this high shear-rate is negligible. At the capillary level the pressure fall is 11.5 mmHg but the vascular resistance W/2r is much lower, on average 32 sec(-1). We can say that if a resistance of 333 sec(-1) corresponds with a pressure fall of 50 mmHg, then a resistance of 32 sec(-1) should correspond with a pressure fall of 4.8 mmHg. The highest pressure fall is due to another kind of resistance which we can define as "Capillary Blood Viscosity" because it depends on the rheological and structural characteristics of the blood. Our instrument reproduces the structure of the capillary district in an experimental model and measures the General Blood Viscosity (GBV) and the Capillary Blood Viscosity (CBV) at the same shear-rate and in particular at the low shear-rate when in non-Newtonian fluids the highest increase in viscosity appears. Consequently, at the capillary, viscosity is dominant with respect to the other geometric and physical resistances. Moreover, the percentage ratio between the GBV and the CBV gives a physical measure of erythrocyte deformability. Knowing viscosity at shear-rate present in the circulatory system, we can obtain the size of RBCs aggregates in the different circulatory districts and their characteristics expressed like "aggregation bond". Changes in CBV are the only possibility in clinical practice to improve the circulatory flow in the capillary district because it is not sure that changes in the arteriolar section can improve the capillary flow or rather open arterio-venous anastomosis. Moreover, in the systemic circulation the aggregate size allows us to point out the phenomenon of cell adhesion because the presence of

  15. Correlation of nanoscale behaviour of forces and macroscale surface wettability.

    PubMed

    Rana, Abhimanyu; Patra, Abhijeet; Annamalai, Meenakshi; Srivastava, Amar; Ghosh, Siddhartha; Stoerzinger, Kelsey; Lee, Yueh-Lin; Prakash, Saurav; Jueyuan, Reuben Yeo; Goohpattader, Partho S; Satyanarayana, Nalam; Gopinadhan, Kalon; Dykas, Michal M; Poddar, Kingshuk; Saha, Surajit; Sarkar, Tarapada; Kumar, Brijesh; Bhatia, Charanjit S; Giordano, Livia; Shao-Horn, Yang; Venkatesan, T

    2016-08-25

    In this manuscript, we demonstrate a method based on atomic force microscopy which enables local probing of surface wettability. The maximum pull-off force, obtained from force spectroscopy shows a remarkable correlation with the macroscopically observed water contact angle, measured over a wide variety of surfaces starting from hydrophilic, all the way through to hydrophobic ones. This relationship, consequently, facilitates the establishment of a universal behaviour. The adhesion forces scale with the polar component of surface energy. However, no such relation could be established with the dispersive component. Hence, we postulate that the force(s) which enable us to correlate the force spectroscopy data measured on the nanoscale to the macroscopic contact angle are primarily arising from electrostatic-dipole-dipole interactions at the solid-liquid interface. London forces play less of a role. This effect in is line with density functional theory (DFT) calculations suggesting a higher degree of hydroxylation of hydrophilic surfaces. This result shows that molecular simulations and measurements on an atomic scale can be extrapolated to macroscopic surface wetting problems. PMID:27510557

  16. 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.

  17. Surface wettability plays a significant role in gecko adhesion underwater.

    PubMed

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

    2013-04-16

    Although we now have thousands of studies focused on the nano-, micro-, and whole-animal mechanics of gecko adhesion on clean, dry substrates, we know relatively little about the effects of water on gecko adhesion. For many gecko species, however, rainfall frequently wets the natural surfaces they navigate. In an effort to begin closing this gap, we tested the adhesion of geckos on submerged substrates that vary in their wettability. When tested on a wet hydrophilic surface, geckos produced a significantly lower shear adhesive force (5.4 ± 1.33 N) compared with a dry hydrophilic surface (17.1 ± 3.93 N). In tests on an intermediate wetting surface and a hydrophobic surface, we found no difference in shear adhesion between dry and wet contact. Finally, in tests on polytetrafluoroethylene (PTFE), we found that geckos clung significantly better to wet PTFE (8.0 ± 1.09 N) than dry PTFE (1.6 ± 0.66 N). To help explain our results, we developed models based on thermodynamic theory of adhesion for contacting surfaces in different media and found that we can predict the ratio of shear adhesion in water to that in air. Our findings provide insight into how geckos may function in wet environments and also have significant implications for the development of a synthetic gecko mimic that retains adhesion in water. PMID:23576727

  18. How does the molecular network structure influence PDMS elastomer wettability?

    NASA Astrophysics Data System (ADS)

    Melillo, Matthew; Genzer, Jan

    Poly(dimethylsiloxane) (PDMS) is one of the most common elastomers, with applications ranging from medical devices to absorbents for water treatment. Fundamental understanding of how liquids spread on the surface of and absorb into PDMS networks is of critical importance for the design and use of another application - microfluidic devices. We have systematically studied the effects of polymer molecular weight, loading of tetra-functional crosslinker, end-group chemical functionality, and the extent of dilution of the curing mixture on the mechanical and surface properties of end-linked PDMS networks. The gel and sol fractions, storage and loss moduli, liquid swelling ratios, and water contact angles have all been shown to vary greatly based on the aforementioned variables. Similar trends were observed for the commercial PDMS material, Sylgard-184. Our results have confirmed theories predicting the relationships between modulus and swelling. Furthermore, we have provided new evidence for the strong influence that substrate modulus and molecular network structure have on the wettability of PDMS elastomers. These findings will aid in the design and implementation of efficient microfluidics and other PDMS-based materials that involve the transport of liquids.

  19. 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

  20. 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

    à 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

  1. 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.

  2. The influence of polydimethylsiloxane curing ratio on capillary pressure in microfluidic devices

    NASA Astrophysics Data System (ADS)

    Viola, Ilenia; Zacheo, Antonella; Arima, Valentina; Aricò, Antonino S.; Cortese, Barbara; Manca, Michele; Zocco, Anna; Taurino, Antonietta; Rinaldi, Ross; Gigli, Giuseppe

    2012-08-01

    Investigations on surface properties of poly(dimethylsiloxane) (PDMS) are justified by its large application ranges especially as coating polymer in fluidic devices. At a micrometer scale, the liquid dynamics is strongly modified by interactions with a solid surface. A crucial parameter for this process is microchannel wettability that can be tuned by acting on surface chemistry and topography. In literature, a number of multi-step, time and cost consuming chemical and physical procedures are reported. Here we selectively modify both wetting and mechanical properties by a single step treatment. Changes of PDMS surface were investigated by X-ray photoelectron spectroscopy and atomic force microscopy and the effects of interface properties on the liquid displacement inside a microfluidic system were evaluated. The negative capillary pressure obtained tailoring the PDMS wettability is believed to be promising to accurately control sample leakage inside integrated lab-on-chip by acting on the liquid confinement and thus to reduce the sample volume, liquid drying as well as cross-contamination during the operation.

  3. Capillary filling dynamics of viscoelastic fluids

    NASA Astrophysics Data System (ADS)

    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.

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

    SciTech Connect

    Hu, Weibai; Zou, Yuzhi; Wang, Qingping

    1995-12-31

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

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

    PubMed

    Chatterjee, Nirmalya; Lapin, Sergey; Flury, Markus

    2012-04-17

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

  6. A rectangular capillary suction apparatus

    SciTech Connect

    Lee, D.J. . Dept. of Chemical Engineering); Hsu, Y.H. . Dept. of Chemical Engineering)

    1994-06-01

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

  7. Capillary electrophoresis in food authenticity.

    PubMed

    Kvasnicka, Frantisek

    2005-06-01

    Food authenticity is a term which simply refers to whether the food purchased by the consumer matches its description. False description can occur in many forms, from the undeclared addition of water or other cheaper materials, or the wrong declaration of the amount of a particular ingredient in the product, to making false statements about the source of ingredients i.e., their geographic, plant, or animal origin. The aim of this review is to summarize applications of capillary electrophoresis in food authentication.

  8. Capillary electrophoresis systems and methods

    SciTech Connect

    Dorairaj, Rathissh; Keynton, Robert S.; Roussel, Thomas J.; Crain, Mark M.; Jackson, Douglas J.; Walsh, Kevin M.; Naber, John F.; Baldwin, Richard P.; Franco, Danielle B.

    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.

  9. A method of test substance removal in agar colony assays using glass capillaries.

    PubMed

    Kastner, M; Maurer, H R

    1984-07-01

    A technique has been developed to remove test substances, after defined incubation periods, from clonogenic in vitro assays using agar-containing glass capillaries. Following removal from the capillaries, the entire agar gels were washed in petri dishes and redrawn into new capillaries. Using 8 radioactive biochemicals of molecular masses ranging from 150 to 1300 dalton the kinetics of diffusion between 1 and 20 min were determined. Using a wash solution-to-assay volume ratio of 20:1, a single washing for 10 min yielded between 90% and 99% removal by diffusion of test substances. By incorporating myelopoietic stem cells it was demonstrated that the cells to be assayed can be quantitatively transferred, without loss or stress, out of and back into capillaries. Thus the reversibility of test substance action can examined under defined conditions avoiding technical problems of previous methods.

  10. Let's twist again: elasto-capillary assembly of parallel ribbons.

    PubMed

    Legrain, Antoine; Berenschot, Erwin J W; Abelmann, Leon; Bico, José; Tas, Niels R

    2016-09-14

    We show the self-assembly through twisting and bending of side by side ribbons under the action of capillary forces. Micro-ribbons made of silicon nitride are batch assembled at the wafer scale. We study their assembly as a function of their dimensions and separating distance. Model experiments are carried out at the macroscopic scale where the tension in ribbons can easily be tuned. The process is modeled considering the competition between capillary, elastic and tension forces. Theory shows a good agreement for macroscale assemblies, while the accuracy is within 30% at the micrometer scale. This simple self-assembly technique yields highly symmetric and controllable structures which could be used for batch fabrication of functional 3D micro-structures. PMID:27501147

  11. 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.

  12. Ionic Liquids in Capillary Electrophoresis.

    PubMed

    Holzgrabe, Ulrike; Wahl, Joachim

    2016-01-01

    Recently, a great interest was drawn toward ionic liquids (ILs) in analytical separation techniques. ILs possess many properties making them excellent additives in capillary electrophoresis (CE) background electrolytes (BGE). The most important property is the charge of the dissolved ions in BGE enabling the cations to interact with deprotonated silanol groups on the capillary surface and thereby modifying the electroosmotic flow (EOF). Ionic and/or proton donor-acceptor interactions between analyte and IL are possible interactions facilitating new kinds of separation mechanisms in CE. Further advantages of ILs are the high conductivity, the environmentally friendliness, and the good solubility for organic and inorganic compounds. The most commonly used ILs in capillary electrophoresis are dialkylimidazolium-based ILs, whereas for enantioseparation a lot of innovative chiral cations and anions were investigated.ILs are reported to be additives to a normal CE background electrolyte or the sole electrolyte in CE, nonaqueous CE (NACE), micellar electrokinetic chromatography (MEKC), and in enantioseparation. An overview of applications and separation mechanisms reported in the literature is given here, in addition to the enantioseparation of pseudoephedrine using tetrabutylammonium chloride (TBAC) as IL additive to an ammonium formate buffer containing β-cyclodextrin (β-CD). PMID:27645735

  13. Capillary Electrophoresis - Optical Detection Systems

    SciTech Connect

    Sepaniak, M. J.

    2001-08-06

    Molecular recognition systems are developed via molecular modeling and synthesis to enhance separation performance in capillary electrophoresis and optical detection methods for capillary electrophoresis. The underpinning theme of our work is the rational design and development of molecular recognition systems in chemical separations and analysis. There have been, however, some subtle and exciting shifts in our research paradigm during this period. Specifically, we have moved from mostly separations research to a good balance between separations and spectroscopic detection for separations. This shift is based on our perception that the pressing research challenges and needs in capillary electrophoresis and electrokinetic chromatography relate to the persistent detection and flow rate reproducibility limitations of these techniques (see page 1 of the accompanying Renewal Application for further discussion). In most of our work molecular recognition reagents are employed to provide selectivity and enhance performance. Also, an emerging trend is the use of these reagents with specially-prepared nano-scale materials. Although not part of our DOE BES-supported work, the modeling and synthesis of new receptors has indirectly supported the development of novel microcantilevers-based MEMS for the sensing of vapor and liquid phase analytes. This fortuitous overlap is briefly covered in this report. Several of the more significant publications that have resulted from our work are appended. To facilitate brevity we refer to these publications liberally in this progress report. Reference is also made to very recent work in the Background and Preliminary Studies Section of the Renewal Application.

  14. 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.

  15. Capillary-driven automatic packaging.

    PubMed

    Ding, Yuzhe; Hong, Lingfei; Nie, Baoqing; Lam, Kit S; Pan, Tingrui

    2011-04-21

    Packaging continues to be one of the most challenging steps in micro-nanofabrication, as many emerging techniques (e.g., soft lithography) are incompatible with the standard high-precision alignment and bonding equipment. In this paper, we present a simple-to-operate, easy-to-adapt packaging strategy, referred to as Capillary-driven Automatic Packaging (CAP), to achieve automatic packaging process, including the desired features of spontaneous alignment and bonding, wide applicability to various materials, potential scalability, and direct incorporation in the layout. Specifically, self-alignment and self-engagement of the CAP process induced by the interfacial capillary interactions between a liquid capillary bridge and the top and bottom substrates have been experimentally characterized and theoretically analyzed with scalable implications. High-precision alignment (of less than 10 µm) and outstanding bonding performance (up to 300 kPa) has been reliably obtained. In addition, a 3D microfluidic network, aligned and bonded by the CAP technique, has been devised to demonstrate the applicability of this facile yet robust packaging technique for emerging microfluidic and bioengineering applications.

  16. 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).

  17. 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)

  18. Dropwise Evaporative Cooling of Heated Surfaces with Various Wettability Characteristics Obtained by Nanostructure Modifications.

    PubMed

    Chen, Jian-Nan; Zhang, Zhen; Ouyang, Xiao-Long; Jiang, Pei-Xue

    2016-12-01

    A numerical and experimental investigation was conducted to analyze dropwise evaporative cooling of heated surfaces with various wettability characteristics. The surface wettability was tuned by nanostructure modifications. Spray-cooling experiments on these surfaces show that surfaces with better wettability have better heat transfer rate and higher critical heat flux (CHF). Single droplet impingement evaporative cooling of a heated surface was then investigated numerically with various wettability conditions to characterize the effect of contact angle on spray-cooling heat transfer. The volume of fluid (VOF) model with variable-time stepping was used to capture the time-dependent liquid-gas interface motion throughout the computational domain with the kinetic theory model used to predict the evaporation rate at the liquid-gas interface. The numerical results agree with the spray-cooling experiments that dropwise evaporative cooling is much better on surfaces with better wettability because of the better liquid spreading and convection, better liquid-solid contact, and stronger liquid evaporation. PMID:27003427

  19. Effect of energetic materials wettability on their outdoor effective elution rate.

    PubMed

    Lapointe, Marie-Claude; Martel, Richard; Lange, Sébastien F; Coté, Sébastien

    2016-07-01

    Energetic materials (EM) contained in military ammunitions have been found in the surface soil and water of training areas and may potentially represent a threat to human health and the environment. EM wettability is an essential physical parameter to characterize because it controls EM dissolution rate. This paper was conducted to determine the wettability of conventional and new EM formulations used in military ammunition. Wettability was estimated in the laboratory via contact angle measurements of water droplets on different EM surfaces. Results show that 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), Octol and energetic thermoplastic elastomer (ETPE) 1000 are hydrophilic while Composition B, XRT, GIM, CX-85, ETPE 2000, and C4 are hydrophobic whereas HELOVA gun propellant has a mixed wettability oscillating between hydrophilic and hydrophobic. The present study demonstrates that wettability of EM formulation is generally controlled by their matrix constituents. Results indicate that hydrophobic formulations have a much slower outdoor environmental effective elution rate than hydrophilic ones, with the exception of the hydrophobic C4 formulation whose elution rate is extremely high. The addition of hydrophobic components into EM formulations is recommended to diminish the environmental impact on water, as it has already been done with XRT, GIM and CX-85 formulations.

  20. Effect of energetic materials wettability on their outdoor effective elution rate.

    PubMed

    Lapointe, Marie-Claude; Martel, Richard; Lange, Sébastien F; Coté, Sébastien

    2016-07-01

    Energetic materials (EM) contained in military ammunitions have been found in the surface soil and water of training areas and may potentially represent a threat to human health and the environment. EM wettability is an essential physical parameter to characterize because it controls EM dissolution rate. This paper was conducted to determine the wettability of conventional and new EM formulations used in military ammunition. Wettability was estimated in the laboratory via contact angle measurements of water droplets on different EM surfaces. Results show that 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), Octol and energetic thermoplastic elastomer (ETPE) 1000 are hydrophilic while Composition B, XRT, GIM, CX-85, ETPE 2000, and C4 are hydrophobic whereas HELOVA gun propellant has a mixed wettability oscillating between hydrophilic and hydrophobic. The present study demonstrates that wettability of EM formulation is generally controlled by their matrix constituents. Results indicate that hydrophobic formulations have a much slower outdoor environmental effective elution rate than hydrophilic ones, with the exception of the hydrophobic C4 formulation whose elution rate is extremely high. The addition of hydrophobic components into EM formulations is recommended to diminish the environmental impact on water, as it has already been done with XRT, GIM and CX-85 formulations. PMID:26985872

  1. Effect of Extreme Wettability on Platelet Adhesion on Metallic Implants: From Superhydrophilicity to Superhydrophobicity.

    PubMed

    Moradi, Sona; Hadjesfandiari, Narges; Toosi, Salma Fallah; Kizhakkedathu, Jayachandran N; Hatzikiriakos, Savvas G

    2016-07-13

    In order to design antithrombotic implants, the effect of extreme wettability (superhydrophilicity to superhydrophobicity) on the biocompatibility of the metallic substrates (stainless steel and titanium) was investigated. The wettability of the surface was altered by chemical treatments and laser ablation methods. The chemical treatments generated different functionality groups and chemical composition as evident from XPS analysis. The micro/nanopatterning by laser ablation resulted in three different pattern geometry and different surface roughness and consequently wettability. The patterned surface were further modified with chemical treatments to generate a wide range of surface wettability. The influence of chemical functional groups, pattern geometry, and surface wettability on protein adsorption and platelet adhesion was studied. On chemically treated flat surfaces, the type of hydrophilic treatment was shown to be a contributing factor that determines the platelet adhesion, since the hydrophilic oxidized substrates exhibit less platelet adhesion in comparison to the control untreated or acid treated surfaces. Also, the surface morphology, surface roughness, and superhydrophobic character of the surfaces are contributing factors to platelet adhesion on the surface. Our results show that superhydrophobic cauliflower-like patterns are highly resistant to platelet adhesion possibly due to the stability of Cassie-Baxter state for this pattern compared to others. Our results also show that simple surface treatments on metals offer a novel way to improve the hemocompatibility of metallic substrates. PMID:27322889

  2. Progression of Diabetic Capillary Occlusion: A Model

    PubMed Central

    Gens, John Scott; Glazier, James A.; Burns, Stephen A.; Gast, Thomas J.

    2016-01-01

    An explanatory computational model is developed of the contiguous areas of retinal capillary loss which play a large role in diabetic maculapathy and diabetic retinal neovascularization. Strictly random leukocyte mediated capillary occlusion cannot explain the occurrence of large contiguous areas of retinal ischemia. Therefore occlusion of an individual capillary must increase the probability of occlusion of surrounding capillaries. A retinal perifoveal vascular sector as well as a peripheral retinal capillary network and a deleted hexagonal capillary network are modelled using Compucell3D. The perifoveal modelling produces a pattern of spreading capillary loss with associated macular edema. In the peripheral network, spreading ischemia results from the progressive loss of the ladder capillaries which connect peripheral arterioles and venules. System blood flow was elevated in the macular model before a later reduction in flow in cases with progression of capillary occlusions. Simulations differing only in initial vascular network structures but with identical dynamics for oxygen, growth factors and vascular occlusions, replicate key clinical observations of ischemia and macular edema in the posterior pole and ischemia in the retinal periphery. The simulation results also seem consistent with quantitative data on macular blood flow and qualitative data on venous oxygenation. One computational model applied to distinct capillary networks in different retinal regions yielded results comparable to clinical observations in those regions. PMID:27300722

  3. Fluid Delivery System For Capillary Electrophoretic Applications.

    DOEpatents

    Li, Qingbo; Liu, Changsheng; Kane, Thomas E.; Kernan, John R.; Sonnenschein, Bernard; Sharer, Michael V.

    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.

  4. Quantifying the cleanliness of glass capillaries.

    PubMed

    Bowman, C L

    1998-01-01

    I used capillary rise methods to investigate the lumenal surface properties of quartz (fused silica, Amersil T-08), borosilicate (Corning 7800), and high-lead glass (Corning 0010) capillaries commonly used to make patch pipets. I calculated the capillary rise and contact angle for water and methanol from weight measurements. The capillary rise was compared with the theoretical maximum value calculated by assuming each fluid perfectly wetted the lumenal surface of the glass (i.e., zero contact angle, which reflects the absence of surface contamination). For borosilicate, high-lead, and quartz capillaries, the rise for water was substantially less than the theoretical maximum rise. Exposure of the borosilicate, lead, and quartz capillaries to several cleaning methods resulted in substantially better--but not perfect--agreement between the theoretical maximum rise and calculated capillary rise. By contrast, the capillary rise for methanol was almost identical in untreated and cleaned capillaries, but less than its theoretical maximum rise. The residual discrepancy between the observed and theoretical rise for water could not be improved on by trying a variety of cleaning procedures, but some cleaning methods were superior to others. The water solubility of the surface contaminants, deduced from the effectiveness of repeated rinsing, was different for each of the three types of capillaries examined: Corning 7800 > quartz > Corning 0010. A surface film was also detected in quatz tubing with an internal filament. I conclude that these borosilicate, quartz, and high-lead glass capillaries have a film on the lumenal surface, which can be removed using appropriate cleaning methods. The surface contaminants may be unique to each type of capillary and may also be hydrophobic. Two simple methods are presented to quantitate the cleanliness of glass capillary tubing commonly used to make pipets for studies of biological membranes. It is not known if the surface film is of

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

    NASA Astrophysics Data System (ADS)

    Özen, İlhan; Şimşek, 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.

  6. 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.

  7. Influence of surface contamination on the wettability of heat transfer surfaces

    DOE PAGES

    Forrest, Eric Christopher; Schulze, Roland; Liu, Cheng; Dombrowski, David

    2015-08-08

    In this study, the wettability of heat transfer surfaces plays an important role in liquid–vapor phase change phenomena, including boiling incipience, the critical heat flux, the Leidenfrost transition, and condensation. The influence of adsorbed surface contamination at the nanoscale, though seldom considered, can have a profound impact on wetting behavior. This study quantitatively investigates the impact of contaminant layer thickness on wettability. Various cleaning treatments are explored on zirconium and 6061 aluminum to determine the effect on contaminant and oxide layer thickness. Angle-resolved X-ray photoelectron spectroscopy can be used to measure the thickness of oxide and contaminant layers, which ismore » then correlated to wettability by measuring the equilibrium contact angle. Results indicate that even after solvent cleaning, the contact angle of water on practical heat transfer surfaces is dominated by a hydrocarbon contaminant overlayer around five nanometers thick.« less

  8. Influence of surface contamination on the wettability of heat transfer surfaces

    SciTech Connect

    Forrest, Eric Christopher; Schulze, Roland; Liu, Cheng; Dombrowski, David

    2015-08-08

    In this study, the wettability of heat transfer surfaces plays an important role in liquid–vapor phase change phenomena, including boiling incipience, the critical heat flux, the Leidenfrost transition, and condensation. The influence of adsorbed surface contamination at the nanoscale, though seldom considered, can have a profound impact on wetting behavior. This study quantitatively investigates the impact of contaminant layer thickness on wettability. Various cleaning treatments are explored on zirconium and 6061 aluminum to determine the effect on contaminant and oxide layer thickness. Angle-resolved X-ray photoelectron spectroscopy can be used to measure the thickness of oxide and contaminant layers, which is then correlated to wettability by measuring the equilibrium contact angle. Results indicate that even after solvent cleaning, the contact angle of water on practical heat transfer surfaces is dominated by a hydrocarbon contaminant overlayer around five nanometers thick.

  9. Fabrication of a wettability-gradient surface on copper by screen-printing techniques

    NASA Astrophysics Data System (ADS)

    Huang, Ding-Jun; Leu, Tzong-Shyng

    2015-08-01

    In this study, a screen-printing technique is utilized to fabricate a wettability-gradient surface on a copper substrate. The pattern definitions on the copper surface were freely fabricated to define the regions with different wettabilities, for which the printing definition technique was developed as an alternative to the existing costly photolithography techniques. This fabrication process using screen printing in tandem with chemical modification methods can easily realize an excellent wettability-gradient surface with superhydrophobicity and superhydrophilicity. Surface analyses were performed to characterize conditions in some fabrication steps. A water droplet movement sequence is provided to clearly demonstrate the droplet-driving effectiveness of the fabricated gradient surface. The droplet-driving efficiency offers a promising solution for condensation heat transfer applications in the foreseeable future.

  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, θ0=0° to θ0=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.

  12. 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

  13. Surface free energy predominates in cell adhesion to hydroxyapatite through wettability.

    PubMed

    Nakamura, Miho; Hori, Naoko; Ando, Hiroshi; Namba, Saki; Toyama, Takeshi; Nishimiya, Nobuyuki; Yamashita, Kimihiro

    2016-05-01

    The initial adhesion of cells to biomaterials is critical in the regulation of subsequent cell behaviors. The purpose of this study was to investigate a mechanism through which the surface wettability of biomaterials can be improved and determine the effects of biomaterial surface characteristics on cellular behaviors. We investigated the surface characteristics of various types of hydroxyapatite after sintering in different atmospheres and examined the effects of various surface characteristics on cell adhesion to study cell-biomaterial interactions. Sintering atmosphere affects the polarization capacity of hydroxyapatite by changing hydroxide ion content and grain size. Compared with hydroxyapatite sintered in air, hydroxyapatite sintered in saturated water vapor had a higher polarization capacity that increased surface free energy and improved wettability, which in turn accelerated cell adhesion. We determined the optimal conditions of hydroxyapatite polarization for the improvement of surface wettability and acceleration of cell adhesion.

  14. 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 θ, 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.

  15. 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.

  16. 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

  17. Surface wettability and platelet adhesion studies on Langmuir Blodgett films

    NASA Astrophysics Data System (ADS)

    Lee, Yuh-Lang; Chen, Chi-Yun

    2003-02-01

    Because Langmuir-Blodgett (LB) deposition technique is known to be capable of preparing highly ordered monomolecular films with densely packed structure, LB technique is used to prepare films of DPPC, DMPC, cholesterol, octadecylamine (ODA), and stearic acid, with thickness of one molecular layer. The film surfaces were characterized by dynamic contact angle measurement and the interaction between blood and these materials were investigated. The properties of LB films were also compared with the results obtained on continuous films prepared by solution dipping. The results show that the contact angles of water on LB films of the five compounds decreases as the following order: ODA> DMPC≈ DPPC> stearic acid > cholesterol. The hydrophobic property reflects the highest organization of ODA molecules on the substrate, which is related to its interaction between the molecule and substrate. The advancing contact angle of ODA is equivalent to that of a methyl-terminated SAM, but its receding contact angle is smaller which implies the exposing of hydrophilic pole or glass substrate on LB film. The irregular orientation of molecules on LB film increases with decreasing of contact angle and is especially significant on LB film of cholesterol which has highest hydrophilic property. The plate adhesion experiments on the continuous films show that the hemocompatibility of the five materials decreases as the order: DPPC≈ DMPC> ODA> cholesterol> stearic acid ≈ glass. This result implies that the lipid has highest blood compatibility, and then -NH 2, and then -OH functionality. On the contrary, the glass surface, -COOH and -CH 3 functionalities have high reactivity to platelet. Due to the possibility of glass exposure on LB films, as estimated from the surface wettability, the LB films have higher platelet reactivity, especially for the cholesterol, compared with the continuous films. Because the interaction of the LB film to the substrate is physical force, the deposited

  18. Variably elastic hydrogel patterned via capillary action in microchannels.

    PubMed

    Dong, Rui; Jensen, Tor W; Engberg, Kristin; Nuzzo, Ralph G; Leckband, Deborah E

    2007-01-30

    Agarose hydrogels of varied elastic modulus can be patterned into 100-microm-wide channels with wall heights of 60 microm. After modifying the hydrogels with chloroacetic acid (acid gels), they are amenable to modification with amine-containing ligands using EDC-NHS chemistry. Using both rheometry and atomic force microscopy (AFM) nanoindentation measurements, the elastic modulus of unmodified hydrogels increases linearly from 3.6 +/- 0.5 kPa to 45.2 +/- 5.5 kPa for 0.5 to 2.0 wt/vol % hydrogel, respectively. The elastic modulus of acid gels is 2.2 +/- 0.3 kPa to 16.2 +/- 1.6 kPa for 0.5 to 2.0 wt/vol %, respectively. No further changes were measured after further modifying the acid gels with fibronectin. Confocal images of rhodamine-modified acid gels show that the optimal filling viscosity of the agarose solutions is between 1 and 4 cP. This new method of patterning allows for the creation of substrates that take advantage of both micron-scale patterns and variably elastic hydrogels.

  19. The spreading of a viscoplastic droplet by capillary action

    NASA Astrophysics Data System (ADS)

    Jalaal, Maziyar; Balmforth, Neil; Stoeber, Boris

    2015-11-01

    The spreading of yield stress liquid droplets on a dry surface occurs in a number of applications such as 3D printing. In the current study, the surface-tension-driven spreading of a yield-stress (Bingham) droplet on a solid wetting surface is studied. Neglecting gravity and using lubrication theory for viscoplastic fluids, we derived the thin film equation in 2D. Equations were solved numerically, where to avoid the moving contact line singularity, we used a pre-wetted film. Numerical solutions show the decelerating spreading of the droplet and its arrest due to the yield stress. Additionally, the final shape of the droplets was constructed, using an asymptotic method. Results were compared with the numerical solutions, where agreements were observed.

  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

  1. Time Evolution of the Wettability of Supported Graphene under Ambient Air Exposure

    PubMed Central

    2016-01-01

    The wettability of graphene is both fundamental and crucial for interfacing in most applications, but a detailed understanding of its time evolution remains elusive. Here we systematically investigate the wettability of metal-supported, chemical vapor deposited graphene films as a function of ambient air exposure time using water and various other test liquids with widely different surface tensions. The wettability of graphene is not constant, but varies with substrate interactions and air exposure time. The substrate interactions affect the initial graphene wettability, where, for instance, water contact angles of ∼85 and ∼61° were measured for Ni and Cu supported graphene, respectively, after just minutes of air exposure. Analysis of the surface free energy components indicates that the substrate interactions strongly influence the Lewis acid–base component of supported graphene, which is considerably weaker for Ni supported graphene than for Cu supported graphene, suggesting that the classical van der Waals interaction theory alone is insufficient to describe the wettability of graphene. For prolonged air exposure, the effect of physisorption of airborne contaminants becomes increasingly dominant, resulting in an increase of water contact angle that follows a universal linear-logarithmic relationship with exposure time, until saturating at a maximum value of 92–98°. The adsorbed contaminants render all supported graphene samples increasingly nonpolar, although their total surface free energy decreases only by 10–16% to about 37–41 mJ/m2. Our finding shows that failure to account for the air exposure time may lead to widely different wettability values and contradicting arguments about the wetting transparency of graphene. PMID:26900413

  2. 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

  3. Measurement of Liquid Viscosities in Tapered or Parabolic Capillaries.

    PubMed

    Ershov; Zorin; Starov

    1999-08-01

    The possibility of using tapered or parabolic capillaries for measurement of liquid viscosities is investigated both experimentally and theoretically. It is demonstrated that even small deviations in capillary radius from a constant value may substantially affect measurement results. Equations are derived which allow correct analysis of the measurement results in tapered or parabolic capillaries. The following cases are analyzed: a water imbibition into a tapered or parabolic capillary and displacement of one liquid by another immiscible liquid in tapered or parabolic capillaries. Two possibilities are considered: (a) the narrow end of the capillary as capillary inlet and (b) the wide end of the capillary as capillary inlet. Copyright 1999 Academic Press.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

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

  5. 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.

  6. Analysis of Small Ions with Capillary Electrophoresis.

    PubMed

    Aulakh, Jatinder Singh; Kaur, Ramandeep; Malik, Ashok Kumar

    2016-01-01

    Small inorganic ions are easily separated through capillary electrophoresis because they have a high charge-to-mass ratio and suffer little from some of the undesired phenomenon affecting higher molecular weight species like adsorption to the capillary wall, decomposition, and precipitation. This chapter is focused on the analysis of small ions other than metal ions using capillary electrophoresis. Methods are described for the determination of ions of nitrogen, phosphorus, sulfur, fluorine, chlorine, bromine, and iodine. PMID:27645739

  7. 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.

  8. Investigations of the impact of wettability heterogeneity on trapping and relative permeability using pore-scale simulations

    NASA Astrophysics Data System (ADS)

    Jiang, F.

    2015-12-01

    Wettability is one of the most important factors influencing the multi-phase fluid flow behavior in porous media. However, the role of wettability at pore-scale still remains poorly understood. In this study, we carried out a series of pore-scale simulations of multiphase displacement process to investigate the impact of wettability heterogeneity on trapping, sweep efficiency and relative permeability using lattice Boltzmann method. We first artificially generated mixed-wet bead pack models with varying degree of wettability by introducing spatial heterogeneity. Based on these models, we then calculated the relative permeability curves and performed the drainage and imbibition simulations to obtain the residual non-wetting phase distributions. The results indicate that strong wettability heterogeneity results in a decrease of non-wetting phase permeability due to the pinned interfaces at wettability discontinuities. The wetting phase permeability as well as the sweep efficiency are largely influenced by the degree of wettability rather than the wettability heterogeneity. The non-wetting phase is observed to be less trapped with strong heterogeneity conditions.

  9. Wettability Behavior of Crude Oil-Silica Nanofluids-Sandstone Systems

    NASA Astrophysics Data System (ADS)

    Bai, Lingyun; Li, Chunyan; Pales, Ashley; Huibers, Britta; Ladner, David; Daigle, Hugh; Darnault, Christophe

    2016-04-01

    Mobilizing and recovering crude oils from geological formations is critical for the management and exploitation of petroleum reservoirs. Nanoparticles, with their unique physico-chemical properties can increase the efficiency of enhanced oil recovery (EOR) by decreasing interfacial tension (IFT) between the oil and aqueous phase systems, and altering rock wettability. Our research examines the potential use of nanoparticles as a means of EOR by studying the influence of silicon oxide (SIO2) nanoparticles on the wettability and interfacial tension of different crude oil-silica nanofluids-sandstone systems. We designed nanofluid treatments to manipulate changes in wettability of Berea and Boise sandstones simulating petroleum reservoir. Experiments were performed to measure the IFT and wettability involving different concentrations of nanoparticles with and without the addition of surfactant to determine which nanofluids produced the most favorable wettability changes for optimal EOR with light crude oil (e.g., West Texas, API: 40), medium crude oil (Prudhoe Bay, API: 28), and heavy crude oil (e.g., Lloydminster, API: 20). We investigated the addition of Tween 20 nonionic surfactant to the nanoparticle dispersions - made from SiO2 nanoparticles - that allows the optimum mobility in porous media through optimization of interfacial tension (IFT) and contact angle, and conducted tests. Batch studies were conducted to measure the IFT and wettability of the nanofluids of different range of nanoparticle concentrations (0-0.1 wt. %) in different reservoir conditions, i.e. brine and brine-surfactant systems made with 5% brine and 2CMC of Tween 20 nonionic surfactants. The dynamic behavior of IFT was monitored using a pendant drop method. Five percent brine-nanoparticle systems containing 0.001 and 0.01 wt.% of nanoparticles resulted in a significant decrease of IFT for light and medium crude oils, while the highest decrease of IFT for heavy crude oil was observed with 0.1 wt

  10. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  12. 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.

  13. 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.

  14. 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

    à 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

  15. Enantiomer Separations by Capillary Electrophoresis.

    PubMed

    Scriba, Gerhard K E; Harnisch, Henrik; Zhu, Qingfu

    2016-01-01

    Capillary electrophoresis (CE) is a versatile and flexible technique for analytical enantioseparations. This is due to the large variety of chiral selectors as well as the different operation modes including electrokinetic chromatography, micellar electrokinetic chromatography, and microemulsion electrokinetic chromatography. The chiral selector, which is added to the background electrolyte, represents a pseudostationary phase with its own electrophoretic mobility allowing a variety of different separation protocols. The present chapter briefly addresses the basic fundamentals of CE enantioseparations as well as the most frequently applied chiral selectors and separation modes. The practical example illustrates the separation of the enantiomers of a positively charged analyte using native and charged cyclodextrin derivatives as chiral selectors. PMID:27645742

  16. Capillary pumped loop application guide

    NASA Astrophysics Data System (ADS)

    Cullimore, Brent A.

    Capillary pumped loops (CPLs) have undergone extensive development since the late 1970's, and represent a maturing technology that is beginning to appear in spacecraft designs. Perhaps because most CPL literature is intended for CPL and heat pipe dedvelopers, or perhaps because of the myriad of component design and layout options available, many thermal control designers are either unfamiliar with the capabilities offered by CPLs, or are confused about their limitations. This survey paper is targeted toward thermal control designers who must decide when and where to use CPLs, or having chosen a CPL solution, must deal with system-level integration and test issues.

  17. Capillary surfaces in exotic containers

    SciTech Connect

    Concus, P. ); Finn, R. . Dept. of Mathematics)

    1991-07-01

    A survey is presented of results to date for capillary surfaces in exotic'' containers. These containers have the property that each one admits a continuum of distinct equilibrium free surfaces, all bounding with the container walls the same volume of fluid, making the same contact angle at the trip interface curve, and having identical mechanical energies. The containers can be so designed that they are themselves axially symmetric but that the fluid configurations of minimizing energy cannot be axially symmetric. 9 refs., 2 figs.

  18. Capillary rafts and their destabilization

    NASA Astrophysics Data System (ADS)

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

    2010-11-01

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

  19. 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.

  20. Capillary electrophoresis in metallodrug development.

    PubMed

    Holtkamp, Hannah; Hartinger, Christian G

    2015-09-01

    Capillary electrophoresis (CE) is a separation method based on differential migration of analytes in electric fields. The compatibility with purely aqueous separation media makes it a versatile tool in metallodrug research. Many metallodrugs undergo ligand exchange reactions that can easily be followed with this method and the information gained can even be improved by coupling the CE to advanced detectors, such as mass spectrometers. This gives the method high potential to facilitate the development of metallodrugs, especially when combined with innovative method development and experimental design. PMID:26547417

  1. Microlithographic wet chemical processing in a capillary space

    NASA Astrophysics Data System (ADS)

    Morgan, Russell

    1994-05-01

    The patented device and procedure described provide a method of processing the flat, thin-film coated surfaces encountered in the ultraclean manufacture of integrated circuit wafers, photomasks, panel displays or other similar substrates. The device provides a means of delivering liquids and vapors to those surfaces while temperature, evaporation and particulate contamination are controlled as a natural consequent of its physical configuration. The essential mechanism exploits the surface tension of liquids and the differences in the wettability of surfaces. By juxtaposing the target surface with a prepared surface on the processing device and maintaining a separation of a few millimeters, the gap formed provides a reaction space into which liquids are easily distributed exploiting so-called capillary behavior. While placing the liquid reagent on the hydrophobic, horizontal surface of the processor, the hydrophilic substrate surface suspended above it is transported laterally. The substrate surface then engages the liquid edge which, driven by its own surface tension, quickly fills the gap. The ending of the reaction and removal of the liquid is effected by further transporting the substrate with its captive liquid reactants to a trench provided in the processor surface where the liquid flows down and away. Thus, the processor surface is seen as a series of 'mesas' allowing a sequence of wet process, rinse and vapor treatments, all with the simple lateral movement of the substrate. The effects of improved reaction kinetics on process precision as well as the benefits mentioned above are discussed and compared to previous immersion and spin methods. Critical dimension measurement data are presented from large photomask substrates processed by the instrument.

  2. Surface fluorination of rutile-TiO2 thin films deposited by reactive sputtering for accelerating response of optically driven capillary effect

    NASA Astrophysics Data System (ADS)

    Kobayashi, Taizo; Maeda, Hironobu; Konishi, Satoshi

    2016-06-01

    We report the acceleration of photoresponsive wettability switching by applying surface fluorination to rutile-TiO2 thin films deposited by reactive sputtering. Photoresponsive wettability switchable surfaces can be applied to optically driven liquid manipulation to enable the elimination of the electrical wiring and pneumatic tubing from fluidic systems. In this work, surface fluorination using CF4 plasma treatment is applied to rutile-TiO2 thin films, which exhibit a wider switching range of wettability than that of anatase-TiO2 thin films. Fluorine termination of TiO2 thin films increases the surface acidity and enhances its photocatalytic performance. TiO2 thin films with and without surface fluorination respectively exhibited the transition of contact angles ranging from 73.7 to 12.3°, and from 70.2 to 32° under UV irradiation for 15 min. Liquid introduction into a microchannel is also demonstrated, utilizing the developed TiO2 surface, which can generate a negative capillary pressure difference under ultraviolet light irradiation.

  3. Breakup length of harmonically stimulated capillary jets - theory and experiments

    NASA Astrophysics Data System (ADS)

    Garcia Garcia, Francisco Javier; Gonzalez Garcia, Heliodoro; Castrejon-Pita, Jose Rafael; Castrejon-Pita, Alfonso Arturo

    2014-11-01

    A stream of liquid breaks up into several drops by the action of surface tension. Capillary breakup forms the basis of some modern digital technologies, especially inkjet printing (including 3D manufacturing). Therefore, the control and prediction of the breakup length of harmonically modulated capillary jets is of great importance, in particular in Continuous InkJet systems (CIJ). However, a theoretical model that rigorously takes into account the physical characteristics of the system, and that properly describes this phenomenon did not exist until now. In this work we present a simple transfer function, derived from first principles, that accurately predicts the experimentally obtained breakup lengths of pressure-modulated capillary jets. No fitting parameters are necessary. A detailed description of the theoretical model and experimental setup will be presented. Spanish government (FIS2011-25161), Junta de Andalucia (P09-FQM-4584 and P11-FQM-7919), EPSRC-UK (EP/H018913/1), Royal Society and John Fell Fund (OUP).

  4. 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

  5. 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.

  6. Cryogenic Capillary Screen Heat Entrapment

    NASA Technical Reports Server (NTRS)

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

    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 sub-cooled propellant conditions and result in feed system cavitation during propellant outflow. Therefore, the fundamental question addressed by this program was: "To what degree is natural convection in a cryogenic liquid constrained by the capillary screen meshes envisioned for LADs.?"Testing was first conducted with water as the test fluid, followed by LN2 tests. In either case, the basic experimental approach was to heat the bottom of a cylindrical column of test fluid to establish stratification patterns measured by temperature sensors located above and below a horizontal screen barrier position. Experimentation was performed without barriers, with screens, and with a solid barrier. The two screen meshes tested were those typically used by LAD designers, "200x1400" and "325x2300", both with Twill Dutch Weave. Upon consideration of both the water and LN2 data it was concluded that heat transfer across the screen meshes was dependent upon barrier thermal conductivity and that the capillary screen meshes were impervious to natural convection currents.

  7. Nonaqueous Capillary Electrophoresis Mass Spectrometry.

    PubMed

    Klampfl, Christian W; Himmelsbach, Markus

    2016-01-01

    The term nonaqueous capillary electrophoresis (NACE) commonly refers to capillary electrophoresis with purely nonaqueous background electrolytes (BGE). Main advantages of NACE are the possibility to analyze substances with very low solubility in aqueous media as well as separation selectivity that can be quite different in organic solvents (compared to water)-a property that can be employed for manipulation of separation selectivities. Mass spectrometry (MS) has become more and more popular as a detector in CE a fact that applies also for NACE. In the present chapter, the development of NACE-MS since 2004 is reviewed. Relevant parameters like composition of BGE and its influence on separation and detection in NACE as well as sheath liquid for NACE-MS are discussed. Finally, an overview of the papers published in the field of NACE-MS between 2004 and 2014 is given. Applications are grouped according to the field (analysis of natural products, biomedical analysis, food analysis, analysis of industrial products, and fundamental investigations). PMID:27645734

  8. Capillary Rise in Porous Media.

    PubMed

    Lago, Marcelo; Araujo, Mariela

    2001-02-01

    Capillary rise experiments were performed in columns filled with glass beads and Berea sandstones, using visual methods to register the advance of the water front. For the glass bead filled columns, early time data are well fitted by the Washburn equation. However, in the experiments, the advancing front exceeded the predicted equilibrium height. For large times, an algebraic behavior of the velocity of the front is observed (T. Delker et al., Phys. Rev. Lett. 76, 2902 (1996)). A model for studying the capillary pressure evolution in a regular assembly of spheres is proposed and developed. It is based on a quasi-static advance of the meniscus with a piston-like motion and allows us to estimate the hydraulic equilibrium height, with values very close to those obtained by fitting early time data to a Washburn equation. The change of regime is explained as a transition in the mechanism of advance of the meniscus. On the other hand, only the Washburn regime was observed for the sandstones. The front velocity was fitted to an algebraical form with an exponent close to 0.5, a value expected from the asymptotic limit of the Washburn equation. Copyright 2001 Academic Press. PMID:11161488

  9. Atomic Force Controlled Capillary Electrophoresis

    NASA Astrophysics Data System (ADS)

    Lewis, Aaron; Yeshua, Talia; Palchan, Mila; Lovsky, Yulia; Taha, Hesham

    2010-03-01

    Lithography based on scanning probe microscopic techniques has considerable potential for accurate & localized deposition of material on the nanometer scale. Controlled deposition of metallic features with high purity and spatial accuracy is of great interest for circuit edit applications in the semiconductor industry, for plasmonics & nanophotonics and for basic research in surface enhanced Raman scattering & nanobiophysics. Within the context of metal deposition we will review the development of fountain pen nanochemistry and its most recent emulation Atomic Force Controlled Capillary Electrophoresis (ACCE). Using this latter development we will demonstrate achievement of unprecedented control of nanoparticle deposition using a three-electrode geometry. Three electrodes are attached: one on the outside of a metal coated glass probe, one on the inside of a hollow probe in a solution containing Au nanoparticles in the capillary, and a third on the surface where the writing takes place. The three electrodes provide electrical pulses for accurate control of deposition and retraction of the liquid from the surface overcoming the lack of control seen in both dip pen lithography & fountain pen nanochemistry when the tip contacts the surface. With this development, we demonstrate depositing a single 1.3 nm Au nanoparticle onto surfaces such as semiconductors.

  10. Acoustic microfluidics: Capillary waves and vortex currents in a spherical fluid drop

    NASA Astrophysics Data System (ADS)

    Lebedev-Stepanov, P. V.; Rudenko, O. V.

    2016-07-01

    We calculate the radiation forces in a spherical drop lying on a solid substrate. The forces form as a result of the action of a capillary wave on a fluid as it propagates along the free spherical surface. We study the structure of acoustic currents excited by the radiation forces.

  11. 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.

  12. 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.

  13. Evaporation of NaCl solution from porous media with mixed wettability

    NASA Astrophysics Data System (ADS)

    Bergstad, Mina; Shokri, Nima

    2016-05-01

    Evaporation of saline water from porous media is ubiquitous in many processes including soil salinization, crop production, and CO2 sequestration in deep saline acquirer. It is controlled by the transport properties of porous media, atmospheric conditions, and properties of the evaporating saline solution. In the present study, the effects of mixed wettability conditions on the general dynamics of water evaporation from porous media saturated with NaCl solution were investigated. To do so, we conducted a comprehensive series of evaporation experiments using sand mixtures containing different fractions of hydrophobic grains saturated with NaCl solutions. Our results showed that increasing fraction of hydrophobic grains in the mixed wettability sand pack had minor impact on the evaporative mass losses due to the presence of salt whose precipitation patterns were significantly influenced by the mixed wettability condition. Through macroscale and microscale investigations, we found formation of patchy efflorescence in the case of mixed wettability sand pack as opposed to crusty efflorescence in the case of completely hydrophilic porous media. Furthermore, the presence of salty water and hydrophobic grains in the sand pack significantly influenced the general dynamics and morphology of the receding drying front. Our results extend the understanding of the saline water evaporation from porous media with direct applications to various hydrological and engineering processes.

  14. 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.

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

    SciTech Connect

    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.

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

    PubMed

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

    2013-11-01

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

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

    PubMed

    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.

  18. 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.

  19. 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.

  20. Enzymophoresis of nucleic acids by tandem capillary enzyme reactor-capillary zone electrophoresis.

    PubMed

    Nashabeh, W; el Rassi, Z

    1992-04-10

    Enzymophoresis with coupled heterogeneous capillary enzyme reactor-capillary zone electrophoresis was developed and evaluated in the area of nucleic acids. Ribonuclease T1, hexokinase and adenosine deaminase were successfully immobilized on the inner walls of short fused-silica capillaries through glutaraldehyde attachment. These open-tubular capillary enzyme reactors were quite stable for a prolonged period of use under operation conditions normally used in capillary zone electrophoresis. The capillary enzyme reactors coupled in series with capillary zone electrophoresis served as peak locator on the electropherogram, improved the system selectivity, and facilitated the quantitative determination of the analytes with good accuracy. Also, they allowed the on-line digestion and mapping of minute amounts of transfer ribonucleic acids, and the simultaneous synthesis and separation of nanogram quantities of oligonucleotides.

  1. 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

  2. Modeling capillary barriers in unsaturated fractured rock

    NASA Astrophysics Data System (ADS)

    Wu, Yu-Shu; Zhang, W.; Pan, Lehua; Hinds, Jennifer; Bodvarsson, G. S.

    2002-11-01

    This work presents a series of numerical modeling studies that investigate the hydrogeologic conditions required to form capillary barriers and the effect that capillary barriers have on fluid flow and tracer transport processes in the unsaturated fractured rock of Yucca Mountain, Nevada, a potential site for storing high-level radioactive waste. The modeling approach is based on a dual-continuum formulation of coupled multiphase fluid and tracer transport through fractured porous rock. The numerical modeling results showed that effective capillary barriers can develop where both matrix and fracture capillary gradients tend to move water upward. Under the current hydrogeologic conceptualization of Yucca Mountain, strong capillary barrier effects exist for diverting a significant amount of moisture flow through the relatively shallow Paintbrush nonwelded unit, with major faults observed at the site serving as major downward pathways for laterally diverted percolation fluxes. In addition, we used observed field liquid saturation and goechemical isotopic data to check model results and found consistent agreement.

  3. 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.

  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 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

  6. 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

  7. Copolymers For Capillary Gel Electrophoresis

    DOEpatents

    Liu, Changsheng; Li, Qingbo

    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.

  8. 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.

  9. 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.

  10. 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.

  11. 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 μm-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 μm-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 μm 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. Micromechanism linear actuator with capillary force sealing

    DOEpatents

    Sniegowski, Jeffry J.

    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.

  13. "Getting the best sensitivity from on-capillary fluorescence detection in capillary electrophoresis" - A tutorial.

    PubMed

    Galievsky, Victor A; Stasheuski, Alexander S; Krylov, Sergey N

    2016-09-01

    Capillary electrophoresis with Laser-Induced Fluorescence (CE-LIF) detection is being applied to new analytical problems which challenge both the power of CE separation and the sensitivity of LIF detection. On-capillary LIF detection is much more practical than post-capillary detection in a sheath-flow cell. Therefore, commercial CE instruments utilize solely on-capillary CE-LIF detection with a Limit of Detection (LOD) in the nM range, while there are multiple applications of CE-LIF that require pM or lower LODs. This tutorial analyzes all aspects of on-capillary LIF detection in CE in an attempt to identify means for improving LOD of CE-LIF with on-capillary detection. We consider principles of signal enhancement and noise reduction, as well as relevant areas of fluorophore photochemistry and fluorescent microscopy. PMID:27543015

  14. Highly Sensitive and Multiple Enzyme Activity Assay Using Reagent-release Capillary-Isoelectric Focusing with Rhodamine 110-based Substrates.

    PubMed

    Sueyoshi, Kenji; Nogawa, Yuto; Sugawara, Kasumi; Endo, Tatsuro; Hisamoto, Hideaki

    2015-01-01

    In this study, a simple and highly sensitive enzyme activity assay based on reagent-release capillary-isoelectric focusing is described. Reagent-release capillaries containing a fluorescent substrate, which produces fluorescent products possessing an isoelectric point after reaction with enzymes, provides a simple procedure. This is because it allows to spontaneously inject a sample solution into the capillary by capillary action, mixing reagents, and subsequently concentrating the fluorescent products based on isoelectric focusing. Fluorescent rhodamine 110 and its monoamide derivative, which were generated as a final product and an intermediate, respectively, were then focused and separated by reagent-release capillary-isoelectric focusing. After 30 min of enzyme reactions, two focused fluorescent bands were clearly isolated along the prepared capillaries. Employing the focused band of rhodamine 110 monoamide allowed for highly sensitive detection of enzyme activity in the 10 pg mL(-1) order, while that of the conventional assay using a microplate was in the ng mL(-1) order. Furthermore, arraying reagent-release capillaries of different substrates on a chip allowed for simultaneous multi-assay of enzyme activity with good sensitivity in the pg mL(-1) order for each protein.

  15. Modification of narrow ablating capillaries under the influence of multiple femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Gubin, K. V.; Lotov, K. V.; Trunov, V. I.; Pestryakov, E. V.

    2016-09-01

    Powerful femtosecond laser pulses that propagate through narrow ablating capillaries cause modification of capillary walls, which is studied experimentally and theoretically. At low intensities, the laser-induced periodic surface structures and porous coating composed of sub-micron particles appear on the walls. At higher intensities, the surface is covered by deposited droplets of the size up to 10 μm. In both cases, the ablated material forms a solid plug that completely blocks the capillary after several hundreds or thousands of pulses. The suggested theoretical model indicates that the plug formation is a universal effect. It must take place in any narrow tube subject to ablation under the action of short laser pulses.

  16. Analysis of protamine peptides in insulin pharmaceutical formulations by capillary electrophoresis.

    PubMed

    Lamalle, Caroline; Servais, Anne-Catherine; Demelenne, Alice; Crommen, Jacques; Fillet, Marianne

    2016-03-01

    Protamines are a group of highly basic peptides that are sometimes added to insulin formulations to prolong the pharmacological action. In this study, different methods were investigated to identify protamine in insulin formulations. Capillary electrophoresis in aqueous and non-aqueous media was tested to separate these peptides with very close amino acid sequences. Different buffers (phosphate or formate, both acidified) and various additives (principally negatively charged and neutral surfactants) were investigated to optimize peptide separation. Finally, a micellar electrokinetic capillary chromatography method using a capillary of 120 cm effective length and an aqueous background electrolyte made up of 100 mM phosphate buffer (pH 2) and 50 mM Thesit® gave the best results, providing the separation of the four major protamine peptides within 25 min. PMID:26829340

  17. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    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.

  18. 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.

  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 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...

  1. Capillary Flow Resistors: Local and Global Resistors.

    PubMed

    Berthier, Jean; Gosselin, David; Pham, Andrew; Delapierre, Guillaume; Belgacem, Naceur; Chaussy, Didier

    2016-01-26

    The use of capillary systems in space and biotechnology applications requires the regulation of the capillary flow velocity. It has been observed that constricted sections act as flow resistors. In this work, we also show that enlarged sections temporarily reduce the velocity of the flow. In this work, the theory of the dynamics of capillary flows passing through a constricted or an enlarged channel section is presented. It is demonstrated that the physics of a capillary flow in a channel with a constriction or an enlargement is different and that a constriction acts as a global flow resistor and an enlargement as a local flow resistor. The theoretical results are checked against experimental approaches. PMID:26704147

  2. Capillary Optics generate stronger X-rays

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA scientist, in the Space Sciences lab at Marshall, works with capillary optics that generate more intense X-rays than conventional sources. This capability is useful in studying the structure of important proteins.

  3. Characterising Microstructured Materials Using a Capillary Rheometer

    NASA Astrophysics Data System (ADS)

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

    2008-07-01

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

  4. ISS Update: Capillary Flow Experiments-2

    NASA Video Gallery

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

  5. RF Liquid Measurement Of Capillary Tubes

    NASA Astrophysics Data System (ADS)

    Poudyal, Bashudev; Mazzeo, Brian; Warnick, Karl

    2009-10-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  7. 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

  8. Photoinduced switchable wettability of bismuth coating with hierarchical dendritic structure between superhydrophobicity and superhydrophilicity

    NASA Astrophysics Data System (ADS)

    Su, Chunping; Lu, Zhong; Zhao, Huiping; Yang, Hao; Chen, Rong

    2015-10-01

    Special wettability such as superhydrophobicity and superhydrophilicity has aroused considerable attention in recent years, especially for the surface that can be switched between superhydrophobicity and superhydrophilicity. In this work, hierarchical bismuth nanostructures with hyperbranched dendritic architectures were synthesized via the galvanic replacement reaction between zinc plate and BiCl3 in ethylene glycol solution, which was composed of a trunk, branches (secondary branch), and leaves (tertiary branch). After being modified by stearic acid, the as-prepared bismuth coating shows superhydrophobicity with a high water contact angle of 164.8° and a low sliding angle of 3°. More importantly, a remarkable surface wettability transition between superhydrophobicity and superhydrophilicity could be easily realized by the alternation of UV-vis irradiation and modification with stearic acid. The tunable wetting behavior of bismuth coating could be used as smart materials to make a great application in practice.

  9. 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, CO2 geosequestration, and microfluidics. PMID:26550879

  10. Wettability-regulated extracellular electron transfer from the living organism of Shewanella loihica PV-4.

    PubMed

    Ding, Chun-mei; Lv, Mei-ling; Zhu, Ying; Jiang, Lei; Liu, Huan

    2015-01-26

    C-type cytochromes located on the outer membrane (OMCs) of genus Shewanella act as the main redox-active species to mediate extracellular electron transfer (EET) from the inside of the outer membrane to the external environment: the central challenge that must be met for successful EET. The redox states of OMCs play a crucial role in dictating the rate and extent of EET. Here, we report that the surface wettability of the electrodes strongly influences the EET activity of living organisms of Shewanella loihica PV-4 at a fixed external potential: the EET activity on a hydrophilic electrode is more than five times higher than that on a hydrophobic one. We propose that the redox state of OMCs varies significantly at electrodes with different wettability, resulting in different EET activities.

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

    PubMed

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

    2009-12-01

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

  12. Soft lithography of ceramic microparts using wettability-tunable poly(dimethylsiloxane) (PDMS) molds

    NASA Astrophysics Data System (ADS)

    Su, Bo; Zhang, Aijun; Meng, Junhu; Zhang, Zhaozhu

    2016-07-01

    Green alumina microparts were fabricated from a high solid content aqueous suspension by microtransfer molding using air plasma-treated poly(dimethylsiloxane) (PDMS) molds. The wettability of the air plasma-treated PDMS molds spontaneously changed between the hydrophilic and hydrophobic states during the process. Initial hydrophilicity of the air plasma-treated PDMS molds significantly improved the flowability of the concentrated suspension. Subsequent hydrophobic recovery of the air plasma-treated PDMS molds enabled a perfect demolding of the green microparts. Consequently, defect-free microchannel parts of 60 μm and a micromixer with an area of several square centimeters were successfully fabricated. In soft lithography, tuning the wetting behavior of PDMS molds has a great effect on the quality of ceramic microparts. Using wettability-tunable PDMS molds has great potential in producing complex-shaped and large-area ceramic microparts and micropatterns.

  13. 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

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

    PubMed

    Das, A K; Das, P K

    2010-06-15

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

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

    SciTech Connect

    Vizika, O.; Lombard, J.M.

    1996-02-01

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

  16. 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.

  17. 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.

  18. Unusual intraosseous capillary hemangioma of the mandible

    PubMed Central

    Dereci, Omur; Acikalin, Mustafa Fuat; Ay, Sinan

    2015-01-01

    Intraosseous hemangioma is a benign vascular neoplasm, which is mostly seen in vertebrae, maxillofacial bones, and long bones. Intraosseous hemangioma is rarely seen on jaw bones compared to other skeletal bones and usually occurs in the cavernous form. Capillary intraosseous hemangioma of jaws is an uncommon form of intraosseous hemangioma and has not been thoroughly described so far. In this study, a case of capillary intraosseous hemangioma of the mandible was presented with relevant literature review. PMID:26430377

  19. Capillary fracture of soft gels

    NASA Astrophysics Data System (ADS)

    Bostwick, Joshua B.; Daniels, Karen E.

    2013-10-01

    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 the surface tension contrast to the gel's elastic modulus, and (ii) the propagation dynamics showing that once fractures are initiated they propagate with a universal power law L∝t3/4. We develop a model for crack initiation by treating the gel as a linear elastic solid and computing the deformations within the substrate from the liquid-solid wetting forces. The elastic solution shows that both the location and the magnitude of the wetting forces are critical in providing a quantitative prediction for the number of fractures and, hence, an interpretation of the initiation of capillary fractures. This solution also reveals that the depth of the gel is an important factor in the fracture process, as it can help mitigate large surface tractions; this finding is confirmed with experiments. We then develop a model for crack propagation by considering the transport of an inviscid fluid into the fracture tip of an incompressible material and find that a simple energy-conservation argument can explain the observed material-independent power law. We compare predictions for both linear elastic and neo-Hookean solids, finding that the latter better explains the observed exponent.

  20. OCT methods for capillary velocimetry.

    PubMed

    Srinivasan, Vivek J; Radhakrishnan, Harsha; Lo, Eng H; Mandeville, Emiri T; Jiang, James Y; Barry, Scott; Cable, Alex E

    2012-03-01

    TO DATE, TWO MAIN CATEGORIES OF OCT TECHNIQUES HAVE BEEN DESCRIBED FOR IMAGING HEMODYNAMICS: Doppler OCT and OCT angiography. Doppler OCT can measure axial velocity profiles and flow in arteries and veins, while OCT angiography can determine vascular morphology, tone, and presence or absence of red blood cell (RBC) perfusion. However, neither method can quantify RBC velocity in capillaries, where RBC flow is typically transverse to the probe beam and single-file. Here, we describe new methods that potentially address these limitations. Firstly, we describe a complex-valued OCT signal in terms of a static scattering component, dynamic scattering component, and noise. Secondly, we propose that the time scale of random fluctuations in the dynamic scattering component are related to red blood cell velocity. Analysis was performed along the slow axis of repeated B-scans to parallelize measurements. We correlate our purported velocity measurements against two-photon microscopy measurements of RBC velocity, and investigate changes during hypercapnia. Finally, we image the ischemic stroke penumbra during distal middle cerebral artery occlusion (dMCAO), where OCT velocimetry methods provide additional insight that is not afforded by either Doppler OCT or OCT angiography.

  1. 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

  2. Multiple capillary biochemical analyzer with barrier member

    DOEpatents

    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.

  3. Capillary pressure experiments under simulated reservoir conditions

    NASA Astrophysics Data System (ADS)

    Kummerow, J.; Spangenberg, E.

    2012-04-01

    The contribution of residual trapping to a long-term storage of CO2 in saline aquifers mainly depends on the drainage capillary pressure of a reservoir and the hysteresis of the drainage and imbibition branches of the capillary pressure curve. However, the experimental database of capillary pressure measured at relevant pT conditions is still scarce. Here, we present an experimental set-up, which allows for the performance of capillary pressure experiments with a semi-permeable disk (porous plate) at simulated reservoir conditions. In the framework of the EU funded project CO2CARE, drainage and imbibition cycles are performed on Triassic sandstone samples. We use a temperature controlled oil pressure autoclave to apply a maximum confining pressure of 400 bar and a maximum working temperature of 150°C. The fluid displacement, and hence the sample saturation is controlled by a gear pump with a fine resolution of 0.01 ml. Additionally, the capillary pressure experiment is combined with measurements of elastic wave velocities as well as of the electrical resistivity. In this case, P and S wave velocities and the formation resistivity factor are determined as functions of the brine/ CO2 saturation. The experiment provides information about the efficiency of the capillary trapping of the sample and a calibration of the petrophysical properties on saturation.

  4. 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.

  5. Cell adhesion during bullet motion in capillaries.

    PubMed

    Takeishi, Naoki; Imai, Yohsuke; Ishida, Shunichi; Omori, Toshihiro; Kamm, Roger D; Ishikawa, Takuji

    2016-08-01

    A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis.

  6. Cell adhesion during bullet motion in capillaries.

    PubMed

    Takeishi, Naoki; Imai, Yohsuke; Ishida, Shunichi; Omori, Toshihiro; Kamm, Roger D; Ishikawa, Takuji

    2016-08-01

    A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis. PMID:27261363

  7. 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.

  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

  9. 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

  10. 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.

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

    PubMed Central

    Sousa, Filipa L.; Silva, Nuno J. O.; Lopes-da-Silva, José A.; Coutinho, João A. P.; Freire, Mara G.

    2016-01-01

    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

  12. 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

    2015-12-21

    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.

  13. A photoresponsive wettability switch based on a dimethylamino calix[4]arene.

    PubMed

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

    2014-07-21

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

  14. Wettability of dentin after Yb:KYW thin-disk femtosecond ablation.

    PubMed

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

    2015-08-01

    The aim of this study was to quantitatively evaluate the wettability of dentin after Yb:KYW thin-disk femtosecond-pulsed laser ablation by measuring the contact angle. Different laser parameters were used including different fluences (F), scanning speeds, and scanning line spacings. Crowns of 15 extracted human teeth were cut longitudinally into slices approximately 1.5-mm thick with a cutting instrument. The samples were randomly divided into ten groups (n = 3/group). Samples in groups 1-8 were irradiated with a femtosecond-pulsed laser. The dentin samples were fixed on a stage at the focal plane, and the laser beam irradiated the samples through a galvanometric scanning system so rectangular movement could be achieved. Samples in groups 9 and 10 were prepared with grinding instruments. Following ablation and preparation, the samples were examined for contact angle with an optical contact angle measuring instrument. The results showed that scanning speed and scanning line spacing had little influence on the wettability of dentin following femtosecond-pulsed laser ablation, except when F = 6 J/cm(2). For six out of the eight laser ablation groups, when a lower fluence was used, the dentin contact angle was higher and vice versa. Most of the dentin which had been ablated using the femtosecond-pulsed laser had improved wettability compared to samples prepared with the grinding instruments. This study showed that various laser fluences, scanning speeds, and scanning line spacings can alter dentin wettability. Therefore, adequate parameters should be chosen to achieve proper therapeutic benefits.

  15. 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 μm radii and micro-silicon chips (1.63-12.1 μN) 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.

  16. Static magnetic fields affect capillary flow of red blood cells in striated skin muscle.

    PubMed

    Brix, Gunnar; Strieth, Sebastian; Strelczyk, Donata; Dellian, Marc; Griebel, Jürgen; Eichhorn, Martin E; Andrā, Wilfried; Bellemann, Matthias E

    2008-01-01

    Blood flowing in microvessels is one possible site of action of static magnetic fields (SMFs). We evaluated SMF effects on capillary flow of red blood cells (RBCs) in unanesthetized hamsters, using a skinfold chamber technique for intravital fluorescence microscopy. By this approach, capillary RBC velocities (v(RBC)), capillary diameters (D), arteriolar diameters (D(art)), and functional vessel densities (FVD) were measured in striated skin muscle at different magnetic flux densities. Exposure above a threshold level of about 500 mT resulted in a significant (P < 0.001) reduction of v(RBC) in capillaries as compared to the baseline value. At the maximum field strength of 587 mT, v(RBC) was reduced by more than 40%. Flow reduction was reversible when the field strength was decreased below the threshold level. In contrast, mean values determined at different exposure levels for the parameters D, D(art), and FVD did not vary by more than 5%. Blood flow through capillary networks is affected by strong SMFs directed perpendicular to the vessels. Since the influence of SMFs on blood flow in microvessels directed parallel to the field as well as on collateral blood supply could not be studied, our findings should be carefully interpreted with respect to the setting of safety guidelines.

  17. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces

    PubMed Central

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-01-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions–dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing. PMID:27063149

  18. Modelling how incorporation of divalent cations affects calcite wettability-implications for biomineralisation and oil recovery.

    PubMed

    Andersson, M P; Dideriksen, K; Sakuma, H; Stipp, S L S

    2016-01-01

    Using density functional theory and geochemical speciation modelling, we predicted how solid-fluid interfacial energy is changed, when divalent cations substitute into a calcite surface. The effect on wettability can be dramatic. Trace metal uptake can impact organic compound adsorption, with effects for example, on the ability of organisms to control crystal growth and our ability to predict the wettability of pore surfaces. Wettability influences how easily an organic phase can be removed from a surface, either organic compounds from contaminated soil or crude oil from a reservoir. In our simulations, transition metals substituted exothermically into calcite and more favourably into sites at the surface than in the bulk, meaning that surface properties are more strongly affected than results from bulk experiments imply. As a result of divalent cation substitution, calcite-fluid interfacial energy is significantly altered, enough to change macroscopic contact angle by tens of degrees. Substitution of Sr, Ba and Pb makes surfaces more hydrophobic. With substitution of Mg and the transition metals, calcite becomes more hydrophilic, weakening organic compound adsorption. For biomineralisation, this provides a switch for turning on and off the activity of organic crystal growth inhibitors, thereby controlling the shape of the associated mineral phase. PMID:27352933

  19. 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

  20. Controlling wettability and hydrophobicity of organoclays modified with quaternary ammonium surfactants.

    PubMed

    Shah, Kinjal J; Mishra, Manish Kumar; Shukla, Atindra D; Imae, Toyoko; Shah, Dinesh O

    2013-10-01

    The montmorillonite clays were modified with quaternary ammonium salts (QASs) having different alkyl chain lengths and a benzyl substitute group. The modified organoclays were characterized by different analytical techniques. The wettability and hydrophilicity/hydrophobicity of the modified clays was evaluated using water or oil penetration (adsorption) and contact angle measurements. The loading of QASs was in the range of 0.60-0.75 mmol/g per clay, irrespective of the type of QAS used for the modification of the clay. From the analytical investigations, it was elucidated that the modification of clay with QAS affected the structural, textural, and surface properties. Moreover, it should be noted that the modification with QAS having benzyl substitute group resulted in water-non-wettable and superhydrophobic surface, whereas clays modified with QAS without benzyl substitute group became more water-wettable and hydrophilic than the pristine clay. The presence of benzyl groups on the clay prevents water from penetration into the inter-clay or interlayer spacing, which yields the hydrophobic surface. These behaviors can arise from molecular arrangement of QAS on clay but not be attributable to the amount of QASs, and the surface area, size, and zeta potential of particles. PMID:23830282

  1. Relationship between wettability and lubrication characteristics of the surfaces of contacting phospholipid-based membranes.

    PubMed

    Pawlak, Zenon; Petelska, Aneta D; Urbaniak, Wieslaw; Yusuf, Kehinde Q; Oloyede, Adekunle

    2013-04-01

    The wettability of the articular surface of cartilage depends on the condition of its surface active phospholipid overlay, which is structured as multi-bilayer. Based on a hypothesis that the surface of cartilage facilitates the almost frictionless lubrication of the joint, we examined the characteristics of this membrane surface entity in both its normal and degenerated conditions using a combination of atomic force microscopy, contact angle measurement, and friction test methods. The observations have led to the conclusions that (1) the acid-base equilibrium condition influences the lubrication effectiveness of the surface of cartilage and (2) the friction coefficient is significantly dependent on the hydrophobicity of the surface of the tissue, thereby confirming the hypothesis tested in this paper. Both wettability angle and interfacial energy were obtained for varying conditions of the cartilage surface both in its wet, dry and lipid-depleted conditions. The interfacial energy also increased with mole fraction of the lipid species reaching an asymptotic value after 0.6. Also, the friction coefficient was found to decrease to an asymptotic level as the wettability angle increased. The result reveal that the interfacial energy increased with pH till pH = 4.0, and then decreased from pH = 4.0 to reach equilibrium at pH = 7.0.

  2. Modelling how incorporation of divalent cations affects calcite wettability-implications for biomineralisation and oil recovery

    NASA Astrophysics Data System (ADS)

    Andersson, M. P.; Dideriksen, K.; Sakuma, H.; Stipp, S. L. S.

    2016-06-01

    Using density functional theory and geochemical speciation modelling, we predicted how solid-fluid interfacial energy is changed, when divalent cations substitute into a calcite surface. The effect on wettability can be dramatic. Trace metal uptake can impact organic compound adsorption, with effects for example, on the ability of organisms to control crystal growth and our ability to predict the wettability of pore surfaces. Wettability influences how easily an organic phase can be removed from a surface, either organic compounds from contaminated soil or crude oil from a reservoir. In our simulations, transition metals substituted exothermically into calcite and more favourably into sites at the surface than in the bulk, meaning that surface properties are more strongly affected than results from bulk experiments imply. As a result of divalent cation substitution, calcite-fluid interfacial energy is significantly altered, enough to change macroscopic contact angle by tens of degrees. Substitution of Sr, Ba and Pb makes surfaces more hydrophobic. With substitution of Mg and the transition metals, calcite becomes more hydrophilic, weakening organic compound adsorption. For biomineralisation, this provides a switch for turning on and off the activity of organic crystal growth inhibitors, thereby controlling the shape of the associated mineral phase.

  3. 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

  4. Thermal singularity and contact line motion in pool boiling: Effects of substrate wettability.

    PubMed

    Taylor, M T; Qian, Tiezheng

    2016-03-01

    The dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)] is employed to model the growth of a single vapor bubble in a superheated liquid on a flat homogeneous substrate. The bubble spreading dynamics in the pool boiling regime has been numerically investigated for one-component van der Waals fluids close to the critical point, with a focus on the effect of the substrate wettability on bubble growth and contact line motion. The substrate wettability is found to control the apparent contact angle and the rate of bubble growth (the rate of total evaporation), through which the contact line speed is determined. An approximate expression is derived for the contact line speed, showing good agreement with the simulation results. This demonstrates that the contact line speed is primarily governed by (1) the circular shape of interface (for slow bubble growth), (2) the constant apparent contact angle, and (3) the constant bubble growth rate. It follows that the contact line speed has a sensitive dependence on the substrate wettability via the apparent contact angle which also determines the bubble growth rate. Compared to hydrophilic surfaces, hydrophobic surfaces give rise to a thinner shape of bubble and a higher rate of total evaporation, which combine to result in a much faster contact line speed. This can be linked to the earlier formation of a vapor film and hence the onset of boiling crisis.

  5. Thermal singularity and contact line motion in pool boiling: Effects of substrate wettability

    NASA Astrophysics Data System (ADS)

    Taylor, M. T.; Qian, Tiezheng

    2016-03-01

    The dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007), 10.1103/PhysRevE.75.036304] is employed to model the growth of a single vapor bubble in a superheated liquid on a flat homogeneous substrate. The bubble spreading dynamics in the pool boiling regime has been numerically investigated for one-component van der Waals fluids close to the critical point, with a focus on the effect of the substrate wettability on bubble growth and contact line motion. The substrate wettability is found to control the apparent contact angle and the rate of bubble growth (the rate of total evaporation), through which the contact line speed is determined. An approximate expression is derived for the contact line speed, showing good agreement with the simulation results. This demonstrates that the contact line speed is primarily governed by (1) the circular shape of interface (for slow bubble growth), (2) the constant apparent contact angle, and (3) the constant bubble growth rate. It follows that the contact line speed has a sensitive dependence on the substrate wettability via the apparent contact angle which also determines the bubble growth rate. Compared to hydrophilic surfaces, hydrophobic surfaces give rise to a thinner shape of bubble and a higher rate of total evaporation, which combine to result in a much faster contact line speed. This can be linked to the earlier formation of a vapor film and hence the onset of boiling crisis.

  6. 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.

  7. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces.

    PubMed

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-01-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions-dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing.

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

    PubMed

    Lee; Lee; Khang; Lee

    2000-10-01

    In this study, the adhesive strength of endothelial cells (ECs) attached on polymer surfaces with different hydrophilicity was investigated using wettability gradient polyethylene (PE) surfaces prepared by corona discharge treatment from a knife-type electrode whose power increases gradually along the sample length. The EC-attached wettability gradient surfaces were mounted on parallel-plate flow chambers in a flow system prepared for cell adhesiveness test. Three different shear stresses (150, 200, and 250 dyne/cm(2)) were applied to the flow chambers and each shear stress was maintained for 120 min to investigate the effect of shear stress and surface hydrophilicity on the EC adhesion strength. It was observed that the ECs were adhered more onto the positions with moderate hydrophilicity of the wettability gradient surface than onto the more hydrophobic or hydrophilic positions. The maximum adhesion of the cells appeared at around water contact angles of 55 degrees. The EC adhesion strength was higher on the hydrophilic positions than on the hydrophobic ones. However, the maximum adhesion strength of the cells also appeared at around water contact angles of 55 degrees. More than 90% of the adhered cells remained on that position after applying the shear stress, 250 dyne/cm(2) for 2 h, whereas the cells were completely detached on the hydrophobic position (water contact angle, about 86 degrees ) within 10 min after applying the same shear stress. It seems that surface hydrophilicity plays a very important role for cell adhesion strength. Copyright 2000 Academic Press.

  9. Thermal singularity and contact line motion in pool boiling: Effects of substrate wettability.

    PubMed

    Taylor, M T; Qian, Tiezheng

    2016-03-01

    The dynamic van der Waals theory [Phys. Rev. E 75, 036304 (2007)] is employed to model the growth of a single vapor bubble in a superheated liquid on a flat homogeneous substrate. The bubble spreading dynamics in the pool boiling regime has been numerically investigated for one-component van der Waals fluids close to the critical point, with a focus on the effect of the substrate wettability on bubble growth and contact line motion. The substrate wettability is found to control the apparent contact angle and the rate of bubble growth (the rate of total evaporation), through which the contact line speed is determined. An approximate expression is derived for the contact line speed, showing good agreement with the simulation results. This demonstrates that the contact line speed is primarily governed by (1) the circular shape of interface (for slow bubble growth), (2) the constant apparent contact angle, and (3) the constant bubble growth rate. It follows that the contact line speed has a sensitive dependence on the substrate wettability via the apparent contact angle which also determines the bubble growth rate. Compared to hydrophilic surfaces, hydrophobic surfaces give rise to a thinner shape of bubble and a higher rate of total evaporation, which combine to result in a much faster contact line speed. This can be linked to the earlier formation of a vapor film and hence the onset of boiling crisis. PMID:27078445

  10. 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).

  11. 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

  12. Amino acid conjugated self assembling molecules for enhancing surface wettability of fiber laser treated titanium surfaces

    NASA Astrophysics Data System (ADS)

    Akkan, Cagri K.; Hür, Deniz; Uzun, Lokman; Garipcan, Bora

    2016-03-01

    Surface wetting properties of implants are one of the most critical parameter, which determine the interaction of proteins and cells with the implant surface. In this regards, acid etching and sand blasting are the mostly used methods at surface modification of Titanium (Ti) for enhanced surface wettability. Besides, these kinds of modifications may cause a conflict whether the surface wettability is influenced by the process related surface contaminations or by the surface roughness. In contrast, lasers might be an option for the alteration of surface wetting properties via supporting micro and/or nano surface topographies while preventing surface chemical contaminations. In this work, we focused on two steps of surface processing approaches of Ti surface: physical and chemical modifications. Herein, we hierarchically structured Ti surfaces by using microsecond modulated pulsed fiber laser. Subsequently, laser structured and non-structured Ti surfaces were further modified with novel histidine and leucine Amino Acid conjugated Self-Assembled Molecules (His1-SAMs2 and Leu3-SAMs) to alter the surface wettability by introducing biologically hydrophilic and hydrophobic groups. Modification of Ti surfaces with His-SAMs and Leu-SAMs ended up with stable wetting properties when compared to non-modified surfaces after 7 days which may enhances the cell-surface interaction.

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

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  14. Wettability alteration properties of fluorinated silica nanoparticles in liquid-loaded pores: An atomistic simulation

    NASA Astrophysics Data System (ADS)

    Sepehrinia, Kazem; Mohammadi, Aliasghar

    2016-05-01

    Control over the wettability of reservoir rocks is of crucial importance for enhancing oil and gas recovery. In order to develop chemicals for controlling the wettability of reservoir rocks, we present a study of functionalized silica nanoparticles as candidates for wettability alteration and improved gas recovery applications. In this paper, properties of fluorinated silica nanoparticles were investigated in water or decane-loaded pores of mineral silica using molecular dynamics simulation. Trifluoromethyl groups as water and oil repellents were placed on the nanoparticles. Simulating a pore in the presence of trapped water or decane molecules leads to liquid bridging for both of the liquids. Adsorption of nanoparticles on the pore wall reduces the density of liquid molecules adjacent to the wall. The density of liquid molecules around the nanoparticles decreases significantly with increasing the number of trifluoromethyl groups on the nanoparticles' surfaces. An increased hydrophobicity of the pore wall was observed in the presence of adsorbed fluorinated silica nanoparticles. Also, it is observed that increasing the number of the trifluoromethyl groups results in weakening of liquid bridges. Moreover, the free energy of adsorption on mineral surface was evaluated to be more favorable than that of aggregation of nanoparticles, which suggests nanoparticles adsorb preferably on mineral surface.

  15. 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.

  16. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces.

    PubMed

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-01-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions-dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing. PMID:27063149

  17. The effects of surface wettability on the fog and dew moisture harvesting performance on tubular surfaces

    NASA Astrophysics Data System (ADS)

    Seo, Donghyun; Lee, Junghun; Lee, Choongyeop; Nam, Youngsuk

    2016-04-01

    The efficient water harvesting from air-laden moisture has been a subject of great interest to address world-wide water shortage issues. Recently, it has been shown that tailoring surface wettability can enhance the moisture harvesting performance. However, depending on the harvesting condition, a different conclusion has often been reported and it remains unclear what type of surface wettability would be desirable for the efficient water harvesting under the given condition. Here we compare the water harvesting performance of the surfaces with various wettability under two different harvesting conditions–dewing and fogging, and show that the different harvesting efficiency of each surface under these two conditions can be understood by considering the relative importance of the water capturing and removal efficiency of the surface. At fogging, the moisture harvesting performance is determined by the water removal efficiency of the surface with the oil-infused surfaces exhibiting the best performance. Meanwhile, at dewing, both the water capturing and removal efficiency are crucial to the harvesting performance. And well-wetting surfaces with a lower barrier to nucleation of condensates exhibit a better harvesting performance due to the increasing importance of the water capture efficiency over the water removal efficiency at dewing.

  18. 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

  19. 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.

  20. 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

  1. Wettability, water sorption and water solubility of seven silicone elastomers used for maxillofacial prostheses.

    PubMed

    Hulterström, Anna Karin; Berglund, Anders; Ruyter, I Eystein

    2008-01-01

    The wettability, water sorption and solubility of silicone elastomers used for maxillofacial prostheses were studied. The hypothesis was, that a material that has absorbed water would show an increase in the wettability and thus also the surface free energy of the material. Seven silicone elastomers, both addition- and condensation type polymers, were included. Five specimens of each material were subjected to treatment according to ISO standards 1567:1999 and 10477: 2004 for water sorption and solubility. The volumes of the specimens were measured according to Archimedes principle. The contact angle was measured with a contact angle goniometer at various stages of the sorption/solubility test. Wettability changed over the test period, but not according to theory. The addition type silicones showed little or no sorption and solubility, but two of the condensation type polymers tested had a significant sorption and solubility. This study showed that condensation type polymers may show too large volumetric changes when exposed to fluids, and therefore should no longer be used in prosthetic devices. The results of this study also suggests that it might be of interest to test sorption and solubility of materials that are to be implanted, since most of the materials had some solubility. PMID:17597370

  2. Understanding disintegrant action by visualization.

    PubMed

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

    2012-06-01

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

  3. Capillary fracture of soft gels.

    PubMed

    Bostwick, Joshua B; Daniels, Karen E

    2013-10-01

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

  4. Microfluidic flow counterbalanced capillary electrophoresis.

    PubMed

    Xia, Ling; Dutta, Debashis

    2013-04-01

    Flow counterbalanced capillary electrophoresis (FCCE) offers a powerful approach to realizing difficult charge based separations in compact microchip devices with application of relatively small electrical voltages. The need for dynamically controlling the pressure-gradient in the FCCE column however presents a significant challenge in implementing this technique on the microchip platform. In this article, we report the use of a simple on-chip pumping unit that allows precise introduction of a periodic pressure-driven backflow into a microfluidic separation channel enabling an FCCE analysis. The backflow in our device was produced by fabricating a shallow segment (0.5 μm deep) downstream of the analysis column (5 μm deep) and applying an electric field across it. A mismatch in the electroosmotic transport rate at the interface of this segment was shown to yield a pressure-gradient that could reverse the flow of the analyte bands without inverting the direction of the electric field. Although such a pressure-gradient also led to additional band broadening in the system, overall, the separation resolution of our device was observed to improve with an increasing number of back-and-forth sample passes through the analysis channel. For our current design, the corresponding improvement in the effective separation length was as much as 52% of the actual distance travelled by the chosen FITC-labeled amino acid samples. The reported device is well suited for further miniaturization of the FCCE method to the nanofluidic length scale which likely would improve its performance, and is easily integrable to other analytical procedures on the microchip platform for lab-on-a-chip applications. PMID:23420375

  5. Capillary fracture of soft gels.

    PubMed

    Bostwick, Joshua B; Daniels, Karen E

    2013-10-01

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

  6. Capillary adhesion at the nanometer scale.

    PubMed

    Cheng, Shengfeng; Robbins, Mark O

    2014-06-01

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

  7. Critical Velocities in Open Capillary Flow

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  8. Separation of Recombinant Therapeutic Proteins Using Capillary Gel Electrophoresis and Capillary Isoelectric Focusing.

    PubMed

    De Jong, Caitlyn A G; Risley, Jessica; Lee, Alexis K; Zhao, Shuai Sherry; Chen, David D Y

    2016-01-01

    Detailed step-by-step methods for protein separation techniques based on capillary electrophoresis (CE) are described in this chapter. Focus is placed on two techniques, capillary gel electrophoresis (CGE) and capillary isoelectric focusing (cIEF). CGE is essentially gel electrophoresis, performed in a capillary, where a hydrogel is used as a sieving matrix to separate proteins or peptides based on size. cIEF separates proteins or peptides based on their isoelectric point (pI), the pH at which the protein or peptide bears no charges. Detailed protocols and steps (including capillary preparation, sample preparation, CE separation conditions, and detection) for both CGE and cIEF presented so that readers can follow the described methods in their own labs. PMID:27473487

  9. N2 and CO2 capillary breakthrough experiments on Opalinus Clay

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    between 3.4 and 12.3 MPa and snap-off pressures from 0.5 to 6.4 MPa. The CO2 experiments yielded breakthrough pressures of 14.0 to 17.5 MPa and snap-off pressures of 3.5 to 10 MPa. No significant changes in single-phase water permeability coefficients before and after the gas breakthrough experiments were observed. In our contribution we will discuss the following points: 1. Gas fluxes occurring during gas breakthrough experiments may be extremely low. Therefore an unambigous identification of gas breakthrough is not always possible. Besides viscous or diffusive transport, dissolution of CO2 in the pore water may affect the observed pressure changes in the upstream and downstream compartments. All of these processes occur simultaneously and can only be partly discriminated. Gas fluxes detected during the diffusion-controlled flow regimes result in nominal effective gas permeability coefficients as low as 6E-25 m² to 7E-24m². 2. The application of purely capillary-controlled flow models may not be justified. o Gas breakthrough is controlled by effective stress, i.e. the opening of pores or small fissures. o Assumptions about wettability (completely water-wet mineral surfaces) may be incorrect.

  10. 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)

  11. Synthetic Capillaries to Control Microscopic Blood Flow

    PubMed Central

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-01-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100–1000 cells, organized hierarchically to express a predictable function. PMID:26905751

  12. 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 μm 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 μM) and linear ranges (between about 10 and 1000 μM). The system was demonstrated for the determination of the inorganic cations in porewater samples of a lake sediment core.

  13. 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)

  14. Restructuring and aging in a capillary suspension

    PubMed Central

    Koos, Erin; Kannowade, Wolfgang; Willenbacher, Norbert

    2014-01-01

    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. PMID:25729113

  15. Case report of lumbar intradural capillary hemangioma

    PubMed Central

    Unnithan, Ajaya Kumar Ayyappan; Joseph, T. P.; Gautam, Amol; Shymole, V.

    2016-01-01

    Background: Capillary hemangioma is a rare tumor in spinal intradural location. Despite the rarity, early recognition is important because of the risk of hemorrhage. This is a case report of a woman who had capillary hemangioma of cauda equina. Case Description: A 54 -year-old woman presented with a low backache, radiating to the left leg for 2 months. She had left extensor hallucis weakness, sensory impairment in left L5 dermatome, and mild tenderness in lower lumbar spine. Magnetic resonance imaging (MRI) LS spine showed L4/5 intradural tumor, completely occluding canal in myelogram, enhancing with contrast, s/o benign nerve sheath tumor. L4 laminectomy was done. Reddish tumor was seen originating from a single root. It was removed preserving the root. Postoperatively, she was relieved of symptoms. MRI showed no residue. Histopathology showed lobular proliferation of capillary-sized blood vessels and elongated spindle cells. Immunohistochemistry showed CD34 positivity in endothelial cell lining of blood vessel and smooth muscle actin positivity in blood vessel muscle cells. HPR-capillary hemangioma. Conclusion: Although rare, capillary hemangioma should be in the differential diagnosis of intradural tumors. It closely mimics nerve sheath tumor. PMID:27069745

  16. Synthetic Capillaries to Control Microscopic Blood Flow

    NASA Astrophysics Data System (ADS)

    Sarveswaran, K.; Kurz, V.; Dong, Z.; Tanaka, T.; Penny, S.; Timp, G.

    2016-02-01

    Capillaries pervade human physiology. The mean intercapillary distance is only about 100 μm in human tissue, which indicates the extent of nutrient diffusion. In engineered tissue the lack of capillaries, along with the associated perfusion, is problematic because it leads to hypoxic stress and necrosis. However, a capillary is not easy to engineer due to its complex cytoarchitecture. Here, it is shown that it is possible to create in vitro, in about 30 min, a tubular microenvironment with an elastic modulus and porosity consistent with human tissue that functionally mimicks a bona fide capillary using “live cell lithography”(LCL) to control the type and position of cells on a composite hydrogel scaffold. Furthermore, it is established that these constructs support the forces associated with blood flow, and produce nutrient gradients similar to those measured in vivo. With LCL, capillaries can be constructed with single cell precision—no other method for tissue engineering offers such precision. Since the time required for assembly scales with the number of cells, this method is likely to be adapted first to create minimal functional units of human tissue that constitute organs, consisting of a heterogeneous population of 100–1000 cells, organized hierarchically to express a predictable function.

  17. Capillary xray compressor: principle versus practice

    NASA Astrophysics Data System (ADS)

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

    1995-09-01

    Guiding x rays down the inside of tapered capillaries is a means to increase the flux density of x rays from synchrotron light sources without some of the disadvantages inherent in other techniques. We have demonstrated that a process based on techniques for fabrication of glass fibers may be used to produce tapered capillaries with inlet diameters on the order of 150 micrometers or more, and outlets on the order of 1 micrometer or less. We present a description of the capillary fabrication and results of tests of the performance of several capillaries, along with a comparison with calculations of performance. We also summarize refinements to the fabrication process that will provide additional improvements. The transmission of x rays from linear capillaries with inlet diameters of approximately 150 micrometers and outlet diameters of 1.3 - 1.4 micrometer is on the order of 2%, with corresponding intensity gains of up to 274. Initial results indicate that the capability exists for producing convex profiles necessary for optimal transmission. Calculated and measured transmission efficiencies are in fairly good agreement, leading to the expectation that efficiencies predicted by calculations to be attainable from optimal profiles are a realistic goal, given the ability to manufacture these profiles.

  18. 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.

  19. Capillary breakup of discontinuously rate thickening suspensions.

    PubMed

    Zimoch, Pawel J; McKinley, Gareth H; Hosoi, A E

    2013-07-19

    Using discontinuously rate thickening suspensions (DRTS) as a model system, we show that beads-on-a-string morphologies can arise as a result of external viscous drag acting during capillary-driven breakup of a non-Newtonian fluid. To minimize the perturbative effect of gravity, we developed a new experimental test platform in which the filament is supported in a horizontal position at the surface of an immiscible oil bath. We show that the evolution of thin DRTS filaments during the capillary thinning process is well described by a set of one-dimensional slender filament equations. The strongly rate-dependent rheology of the test fluid and the aspect ratio of the filament couple to control the thinning dynamics and lead to a simple criterion describing the localized arrest of the capillary thinning process and the subsequent formation of complex, high aspect ratio beads-on-a-string structures. PMID:23909338

  20. Modeling the effect of surface forces on the equilibrium liquid profile of a capillary meniscus.

    PubMed

    Kuchin, Igor V; Matar, Omar K; Craster, Richard V; Starov, Victor M

    2014-08-28

    The equilibrium profile of a capillary meniscus formed under combined action of disjoining/conjoining and capillarity pressures is investigated. Attention is focused on the shape of a transition zone between a spherical meniscus and a thin liquid film in front of the meniscus. The Poisson-Boltzmann equation is used for calculations of electrostatic contribution to the disjoining/conjoining pressure and the liquid shape inside the transition zone. Both complete and partial wetting conditions are investigated. PMID:24998938