Ring cavity for a raman capillary waveguide amplifier

DOEpatents

Kurnit, Norman A.

1983-07-19

A regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO.sub.2 laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO.sub.2 laser pump signal.

Demonstration of a high repetition rate capillary discharge waveguide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gonsalves, A. J., E-mail: ajgonsalves@lbl.gov; Pieronek, C.; Daniels, J.

2016-01-21

A hydrogen-filled capillary discharge waveguide operating at kHz repetition rates is presented for parameters relevant to laser plasma acceleration (LPA). The discharge current pulse was optimized for erosion mitigation with laser guiding experiments and MHD simulation. Heat flow simulations and measurements showed modest temperature rise at the capillary wall due to the average heat load at kHz repetition rates with water-cooled capillaries, which is promising for applications of LPAs such as high average power radiation sources.

Optimization of gas-filled quartz capillary discharge waveguide for high-energy laser wakefield acceleration

NASA Astrophysics Data System (ADS)

Qin, Zhiyong; Li, Wentao; Liu, Jiansheng; Liu, Jiaqi; Yu, Changhai; Wang, Wentao; Qi, Rong; Zhang, Zhijun; Fang, Ming; Feng, Ke; Wu, Ying; Ke, Lintong; Chen, Yu; Wang, Cheng; Li, Ruxin; Xu, Zhizhan

2018-04-01

A hydrogen-filled capillary discharge waveguide made of quartz is presented for high-energy laser wakefield acceleration (LWFA). The experimental parameters (discharge current and gas pressure) were optimized to mitigate ablation by a quantitative analysis of the ablation plasma density inside the hydrogen-filled quartz capillary. The ablation plasma density was obtained by combining a spectroscopic measurement method with a calibrated gas transducer. In order to obtain a controllable plasma density and mitigate the ablation as much as possible, the range of suitable parameters was investigated. The experimental results demonstrated that the ablation in the quartz capillary could be mitigated by increasing the gas pressure to ˜7.5-14.7 Torr and decreasing the discharge current to ˜70-100 A. These optimized parameters are promising for future high-energy LWFA experiments based on the quartz capillary discharge waveguide.

Note: Characterization of the plasma parameters of a capillary discharge-produced plasma channel waveguide to guide an intense laser pulse

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higashiguchi, Takeshi; Yugami, Noboru; CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kanagawa, Saitama 332-0012

2010-04-15

We demonstrated the production of an optical waveguide in a capillary discharge-produced plasma using a cylindrical capillary. Plasma parameters of its waveguide were characterized by use of both a Nomarski laser interferometer and a hydrogen plasma line spectrum. A space-averaged maximum temperature of 3.3 eV with electron densities of the order of 10{sup 17} cm{sup -3} was observed at a discharge time of 150 ns and a maximum discharge current of 400 A. An ultrashort, intense laser pulse was guided by use of this plasma channel.

Ring cavity for a Raman capillary waveguide amplifier

DOEpatents

Kurnit, N.A.

1983-07-19

Disclosed is a regenerative ring amplifier and regenerative ring oscillator which function to feed back a portion of the Stokes signal to complete the ring cavity. The ring cavity configuration allows the CO[sub 2] laser pump signal and Stokes signal to copropagate through the Raman capillary waveguide amplifier. A Raman capillary waveguide amplifier is also provided in the return leg of the ring cavity to increase gain without increasing the round trip time. Additionally, the ring cavity can be designed such that the amplifier Stokes signal is synchronous with the mode-locked spikes of the incoming CO[sub 2] laser pump signal. 6 figs.

Online High Temporal Resolution Measurement of Atmospheric Sulfate and Sulfur Trioxide with a Light Emitting Diode and Liquid Core Waveguide-Based Sensor.

PubMed

Tian, Yong; Shen, Huiyan; Wang, Qiang; Liu, Aifeng; Gao, Wei; Chen, Xu-Wei; Chen, Ming-Li; Zhao, Zongshan

2018-06-13

High temporal resolution components analysis is still a great challenge for the frontier of atmospheric aerosol research. Here, an online high time resolution method for monitoring soluble sulfate and sulfur trioxide in atmospheric aerosols was developed by integrating a membrane-based parallel plate denuder, a particle collector, and a liquid waveguide capillary cell into a flow injection analysis system. The BaCl 2 solution (containing HCl, glycerin, and ethanol) was enabled to quantitatively transform sulfate into a well-distributed BaSO 4 solution for turbidimetric detection. The time resolution for monitoring the soluble sulfate and sulfur trioxide was 15 h -1 . The limits of detection were 86 and 7.3 μg L -1 ( S/ N = 3) with a 20 and 200 μL SO 4 2- solution injection, respectively. Both the interday and intraday precision values (relative standard deviation) were less than 6.0%. The analytical results of the certificated reference materials (GBW(E)08026 and GNM-M07117-2013) were identical to the certified values (no significant difference at a 95% confidence level). The validity and practicability of the developed device were also evaluated during a firecracker day and a routine day, obviously revealing the continuous variance in atmospheric sulfate and sulfur trioxide in both interday and intraday studies.

Terahertz particle-in-liquid sensing with spoof surface plasmon polariton waveguides

NASA Astrophysics Data System (ADS)

Ma, Zhijie; Hanham, Stephen M.; Arroyo Huidobro, Paloma; Gong, Yandong; Hong, Minghui; Klein, Norbert; Maier, Stefan A.

2017-11-01

We present a highly sensitive microfluidic sensing technique for the terahertz (THz) region of the electromagnetic spectrum based on spoof surface plasmon polaritons (SPPs). By integrating a microfluidic channel in a spoof SPP waveguide, we take advantage of these highly confined electromagnetic modes to create a platform for dielectric sensing of liquids. Our design consists of a domino waveguide, that is, a series of periodically arranged rectangular metal blocks on top of a metal surface that supports the propagation of spoof SPPs. Through numerical simulations, we demonstrate that the transmission of spoof SPPs along the waveguide is extremely sensitive to the refractive index of a liquid flowing through a microfluidic channel crossing the waveguide to give an interaction volume on the nanoliter scale. Furthermore, by taking advantage of the insensitivity of the domino waveguide's fundamental spoof SPP mode to the lateral width of the metal blocks, we design a tapered waveguide able to achieve further confinement of the electromagnetic field. Using this approach, we demonstrate the highly sensitive detection of individual subwavelength micro-particles flowing in the liquid. These results are promising for the creation of spoof SPP based THz lab-on-a-chip microfluidic devices that are suitable for the analysis of biological liquids such as proteins and circulating tumour cells in buffer solution.

Nanoscale Plasmonic V-Groove Waveguides for the Interrogation of Single Fluorescent Bacterial Cells.

PubMed

Lotan, Oren; Bar-David, Jonathan; Smith, Cameron L C; Yagur-Kroll, Sharon; Belkin, Shimshon; Kristensen, Anders; Levy, Uriel

2017-09-13

We experimentally demonstrate the interrogation of an individual Escherichia coli cell using a nanoscale plasmonic V-groove waveguide. Several different configurations were studied. The first involved the excitation of the cell in a liquid environment because it flows on top of the waveguide nanocoupler, while the obtained fluorescence is coupled into the waveguide and collected at the other nanocoupler. The other two configurations involved the positioning of the bacterium within the nanoscale waveguide and its excitation in a dry environment either directly from the top or through waveguide modes. This is achieved by taking advantage of the waveguide properties not only for light guiding but also as a mechanical tool for trapping the bacteria within the V-grooves. The obtained results are supported by a set of numerical simulations, shedding more light on the mechanism of excitation. This demonstration paves the way for the construction of an efficient bioplasmonic chip for diverse cell-based sensing applications.

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.

Stokes injected Raman capillary waveguide amplifier

DOEpatents

Kurnit, Norman A.

1980-01-01

A device for producing stimulated Raman scattering of CO.sub.2 laser radiation by rotational states in a diatomic molecular gas utilizing a Stokes injection signal. The system utilizes a cryogenically cooled waveguide for extending focal interaction length. The waveguide, in conjunction with the Stokes injection signal, reduces required power density of the CO.sub.2 radiation below the breakdown threshold for the diatomic molecular gas. A Fresnel rhomb is employed to circularly polarize the Stokes injection signal and CO.sub.2 laser radiation in opposite circular directions. The device can be employed either as a regenerative oscillator utilizing optical cavity mirrors or as a single pass amplifier. Additionally, a plurality of Raman gain cells can be staged to increase output power magnitude. Also, in the regenerative oscillator embodiment, the Raman gain cell cavity length and CO.sub.2 cavity length can be matched to provide synchronism between mode locked CO.sub.2 pulses and pulses produced within the Raman gain cell.

Investigation and visualization of liquid-liquid flow in a vertically mounted Hele-Shaw cell: flow regimes, velocity and shape of droplets

NASA Astrophysics Data System (ADS)

Shad, S.; Gates, I. D.; Maini, B. B.

2009-11-01

The motion and shape of a liquid drop flowing within a continuous, conveying liquid phase in a vertical Hele-Shaw cell were investigated experimentally. The continuous phase was more viscous and wetted the bounding walls of the Hele-Shaw cell. The gap between the Hele-Shaw plates was set equal to 0.0226 cm. Four different flow regimes were observed: (a) small-droplet flow, (b) elongated-droplet flow, (c) churn flow and (d) channel flow. At low capillary number, that is, when capillary forces are larger than viscous forces, the droplet shape was irregular and changed with time and distance, and it moved with lower velocity than that of the conveying phase. At higher capillary number, several different shapes of stabilized elongated and flattened drops were observed. In contrast to gas-liquid systems, the velocities of droplets are higher than that of conveying liquid. New correlations derived from dimensionless analysis and fitted to the experimental data were generated to predict the elongated-drop velocity and aspect ratio.

Advanced Gas Sensors Using SERS-Activated Waveguides

NASA Astrophysics Data System (ADS)

Lascola, Robert; McWhorter, Scott; Murph, Simona Hunyadi

2010-08-01

This contribution describes progress towards the development and testing of a functionalized capillary that will provide detection of low-concentration gas-phase analytes through SERS. Measurement inside a waveguide allows interrogation of a large surface area, potentially overcoming the short distance dependence of the SERS effect. The possible use of Raman spectroscopy for gas detection is attractive for IR-inactive molecules or scenarios where infrared technology is inconvenient. However, the weakness of Raman scattering limits the use of the technique to situations where low detection limits are not required or large gas pressures are present. With surface-enhanced Raman spectroscopy (SERS), signal enhancements of 106 are often claimed, and higher values are seen in specific instances. However, most of the examples of SERS analysis are on liquid-phase samples, where the molecular density is high, usually combined with some sort of sample concentration at the surface. Neither of these factors is present in gas-phase samples. Because the laser is focused to a small point in the typical experimental setup, and the spatial extent of the effect above the surface is small (microns), the excitation volume is miniscule. Thus, exceptionally large enhancements are required to generate a signal comparable to that obtained by conventional Raman measurements. A reflective waveguide offers a way to increase the interaction volume of the laser with a SERS-modified surface. The use of a waveguide to enhance classical Raman measurements was recently demonstrated by S.M. Angel and coworkers, who obtained 12- to 30-fold sensitivity improvements for nonabsorbing gases (CO2, CH4) with a silvered capillary (no SERS enhancement). Shi et al.. demonstrated 10-to 100-fold enhancement of aqueous Rhodamine 6G in a capillary coated with silver nanoparticles. They observed enhancements of 10- to 100-fold compared to direct sampling, but this relied on a "double substrate", which required non-specific interactions between the surface coating and additional nanoparticles suspended in solution to which the analyte had been coupled. Clearly, for a gas sensor, such a scheme is not feasible, and in any event the reliance on the random configuration of the nanoparticles and the analyte is not expected to lead to efficient enhancement. Here, we report the creation of capillary coatings of self-assembled, aggregated high aspect ratio metallic nanoparticles (e.g. rod, wires) with a solution-phase technique. Self-assembly offers the possibility for a high density of SERS hot spots, which are often observed at the junction of adjacent particles. Shaped nanoparticles also enhance self-assembled deposition, and allow further control of the optical properties of the coating through manipulation of the morphology. SERS enhancements for gases are reported relative to mirrored capillaries and free-space measurements.

Nanoparticle sorting in silicon waveguide arrays

NASA Astrophysics Data System (ADS)

Zhao, H. T.; Zhang, Y.; Chin, L. K.; Yap, P. H.; Wang, K.; Ser, W.; Liu, A. Q.

2017-08-01

This paper presents the optical fractionation of nanoparticles in silicon waveguide arrays. The optical lattice is generated by evanescent coupling in silicon waveguide arrays. The hotspot size is tunable by changing the refractive index of surrounding liquids. In the experiment, 0.2-μm and 0.5-μm particles are separated with a recovery rate of 95.76%. This near-field approach is a promising candidate for manipulating nanoscale biomolecules and is anticipated to benefit the biomedical applications such as exosome purification, DNA optical mapping, cell-cell interaction, etc.

Validation and perspectives of a femtosecond laser fabricated monolithic optical stretcher

PubMed Central

Bellini, Nicola; Bragheri, Francesca; Cristiani, Ilaria; Guck, Jochen; Osellame, Roberto; Whyte, Graeme

2012-01-01

The combination of high power laser beams with microfluidic delivery of cells is at the heart of high-throughput, single-cell analysis and disease diagnosis with an optical stretcher. So far, the challenges arising from this combination have been addressed by externally aligning optical fibres with microfluidic glass capillaries, which has a limited potential for integration into lab-on-a-chip environments. Here we demonstrate the successful production and use of a monolithic glass chip for optical stretching of white blood cells, featuring microfluidic channels and optical waveguides directly written into bulk glass by femtosecond laser pulses. The performance of this novel chip is compared to the standard capillary configuration. The robustness, durability and potential for intricate flow patterns provided by this monolithic optical stretcher chip suggest its use for future diagnostic and biotechnological applications. PMID:23082304

On-line wall-free cell for laser-induced fluorescence detection in capillary electrophoresis.

PubMed

Yu, Chang-Zhu; He, You-Zhao; Xie, Hai-Yang; Gao, Yong; Gan, Wu-Er; Li, Jun

2009-05-15

A wall-free detection method based on liquid junction in a capillary gap was proposed for laser-induced fluorescence (LIF) of capillary electrophoresis (CE). The capillary gap of the wall-free cell was fabricated by etching a 10-mm x 50-microm I.D. fused-silica capillary to obtain a polyimide coating sleeve, decoating about 6mm at one end of both 50 microm I.D. separation and liquid junction capillary, inserting the treated capillary ends into the coating sleeve oppositely, fixing the capillaries with a gap distance of 140 microm by epoxy glue and removing the coating sleeve by burning. The theoretical model, experimental results and wall-free cell images indicated that the gap distance and applied voltage were main influence factors on the wall-free detection. Since the wall-free cell increased the absorption light path and avoided the stray light from the capillary wall, it improved the ratio of signal to noise and limit of detection (LOD) of CE-LIF. Three flavin compounds of riboflavin (RF), flavin mononucleotide sodium (FMN) and flavin adenine dinucleotide disodium (FAD) were used to evaluate the wall-free detection method. Compared with on-column cell, the LODs of the wall-free cell were improved 15-, 6- and 9-fold for RF, FMN and FAD, respectively. The linear calibration concentrations of the flavins ranged from 0.005 to 5.0 micromol/L. The column efficiency was in the range from 1.0 x 10(5) to 2.5 x 10(5) plates. The wall-free detection of CE-LIF was applied to the analysis of the flavins in spinach and lettuce leaves.

Micromachined evaporators for AMTEC cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Izenson, M.G.; Crowley, C.J.

1996-12-31

To achieve high cell efficiency and reliability, the capillary pumping system for Alkali Metal Thermal to Electric Conversion (AMTEC) must have three key characteristics: (1) very small pores to achieve a high capillary pumping head, (2) high permeability for the flow of liquid sodium to minimize internal losses, and (3) be made from a material that is exceptionally stable at high temperatures in a sodium environment. The authors have developed micromachining techniques to manufacture high performance evaporators for AMTEC cells. The evaporators have been fabricated from stainless steel, molybdenum, and a niobium alloy (Nb-1Zr). The regular, micromachined structure leads tomore » very high capillary pumping head with high permeability for liquid flow. Data from tests performed with common fluids at room temperature characterize the capillary pumping head and permeability of these structures. Three micromachined evaporators have been built into AMTEC cells and operated at temperatures up to 1,100 K. Results from these tests confirm the excellent pumping capabilities of the micromachined evaporators.« less

Intense laser pulse propagation in ionizing gases

NASA Astrophysics Data System (ADS)

Bian, Zhigang

2003-10-01

There have been considerable technological advances in the development of high intensity, short pulse lasers. However, high intensity laser pulses are subject to various laser-plasma instabilities. In this thesis, a theory is developed to study the scattering instability that occurs when a laser pulse propagates through and ionizes a gas. The instability is due to the intensity dependence of the ionization rate, which leads to a transversely structured free electron density. The instability is convective in the frame of laser pulse, but can have a relatively short growth length scaling as Lg˜k0/k2p where k0 is the laser wave number, k2p=w2p/c 2 and op is the plasma frequency. The most unstable perturbations correspond to a scattering angle for which the transverse wave number is around the plasma wave number, k p. The scattered light is frequency upshifted. The comparison between simple analytic theory and numerical simulation shows good agreement. Instabilities can drastically change the shape of the laser pulse and reduce the propagation distance of the laser pulse. Therefore, we change the propagation conditions and reduce the laser-plasma interaction possibilities in applications which require an interaction length well in excess of the Rayleigh length of the laser beam. One of the methods is to use a capillary to propagate the laser pulse. We studied the propagation of short pulses in a glass capillary. The propagation is simulated using the code WAKE, which has been modified to treat the case in which the simulation boundary is the wall of a capillary. Parameters that were examined include transmission efficiency of the waveguides as a function of gas pressure, laser intensity, and waveguide length, which is up to 40 Rayleigh lengths. The transmission efficiency decreases with waveguide length due to energy loss through the side-walls of the capillary. The loss increases with gas pressure due to ionization of the gas and scattering of the radiation. The intensity on the inner wall of the capillary is monitored to assure realistic simulations, consistent with optical breakdown of the waveguide material. Generally speaking the intensity on the wall increases with gas pressure due to the scattering of the lowest order capillary mode. Finally, the high order harmonic generation (HHG) in a capillary is investigated. The phase matching condition is studied to increase the conversion efficiency for high order harmonics generation. The phase matching occurs as a balance of the dispersion of the neutral gas, plasma and the waveguide.

Liquid waveguide spectrophotometric measurement of nanomolar ammonium in seawater based on the indophenol reaction with o-phenylphenol (OPP).

PubMed

Hashihama, Fuminori; Kanda, Jota; Tauchi, Ami; Kodama, Taketoshi; Saito, Hiroaki; Furuya, Ken

2015-10-01

We describe a highly sensitive colorimetric method for the determination of nanomolar concentrations of ammonium in seawater based on the indophenol reaction with o-phenylphenol [(1,1'-biphenyl)-2-ol, abbreviated as OPP]. OPP is available as non-toxic, stable flaky crystals with no caustic odor and has some advantages over phenol in practical use. The method was established by using a gas-segmented continuous flow analyzer equipped with two types of long path liquid waveguide capillary cell, LWCCs (100 cm and 200 cm) and an UltraPath (200 cm), which have inner diameters of 0.55 mm and 2 mm, respectively. The reagent concentrations, flow rates of the pumping tubes, and reaction path and temperature were determined on the basis of a manual indophenol blue method with OPP (Kanda, Water Res. 29 (1995) 2746-2750). The sample mixed with reagents that form indophenol blue dye was measured at 670 nm. Aged subtropical surface water was used as a blank, a matrix of standards, and the carrier. The detection limits of the analytical systems with a 100 cm LWCC, a 200 cm LWCC, and a 200 cm UltraPath were 6, 4, and 4 nM, respectively. These systems had high precision (<4% at 100 nM) and a linear dynamic range up to 200 nM. Non-linear baseline drift did not occur when using the UltraPath system. This is due to the elimination of cell clogging because of the larger inner diameter of the UltraPath compared to the LWCCs. The UltraPath system is thus more suitable for long-term measurements compared with the LWCC systems. The results of the proposed sensitive colorimetry and a conventional colorimetry for the determination of seawater samples showed no significant difference. The proposed analytical systems were applied to underway surface monitoring and vertical observation in the oligotrophic South Pacific. Copyright © 2015 Elsevier B.V. All rights reserved.

Lasing in a nematic liquid crystal cell with an interdigitated electrode system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shtykov, N M; Palto, S P; Umanskii, B A

2015-04-30

Waveguide lasing in a layer of a dye-doped nematic liquid crystal has been observed. The liquid-crystal layer was sandwiched between a quartz substrate and a glass cover plate on whose surface was deposited an interdigitated electrode system. This system had a period of 3.75 μm and played a dual role, namely, it created a spatial periodicity of the waveguide medium refractive index (thus creating distributed feedback) and served as a diffraction grating coupling out a part of waveguide radiation into the glass cover plate. The distributed feedback ensured lasing in the 18th diffraction order for the TE modes and inmore » the 19th order for the TM modes of the waveguide. The generated radiation was observed at the exit from the glass plate end face at the angles to the waveguide plane of 33.1 ± 1.5° for TM modes and 21.8 ± 1.8° for TE modes. The intensity and position of the TE emission line showed no regular dependence on the voltage on the electrodes. In the case of TM radiation, an increase in the voltage led to a short-wavelength shift of the laser line and to a decrease in its intensity. (lasers)« less

High-order harmonic generation in a capillary discharge

DOEpatents

Rocca, Jorge J.; Kapteyn, Henry C.; Mumane, Margaret M.; Gaudiosi, David; Grisham, Michael E.; Popmintchev, Tenio V.; Reagan, Brendan A.

2010-06-01

A pre-ionized medium created by a capillary discharge results in more efficient use of laser energy in high-order harmonic generation (HHG) from ions. It extends the cutoff photon energy, and reduces the distortion of the laser pulse as it propagates down the waveguide. The observed enhancements result from a combination of reduced ionization energy loss and reduced ionization-induced defocusing of the driving laser as well as waveguiding of the driving laser pulse. The discharge plasma also provides a means to spectrally tune the harmonics by tailoring the initial level of ionization of the medium.

Fluorescent optical liquid level sensor

DOEpatents

Weiss, Jonathan D.

2001-01-01

A liquid level sensor comprising a transparent waveguide containing fluorescent material that is excited by light of a first wavelength and emits at a second, longer wavelength. The upper end of the waveguide is connected to a light source at the first wavelength through a beveled portion of the waveguide such that the input light is totally internally reflected within the waveguide above an air/liquid interface in a tank but is transmitted into the liquid below this interface. Light is emitted from the fluorescent material only in those portions of the waveguide that are above the air/liquid interface, to be collected at the upper end of the waveguide by a detector that is sensitive only to the second wavelength. As the interface moves down in the tank, the signal strength from the detector will increase.

Phase-field modeling of liquids splitting between separating surfaces and its application to high-resolution roll-based printing technologies

NASA Astrophysics Data System (ADS)

Hizir, F. E.; Hardt, D. E.

2017-05-01

An in-depth understanding of the liquid transport in roll-based printing systems is essential for advancing the roll-based printing technology and enhancing the performance of the printed products. In this study, phase-field simulations are performed to characterize the liquid transport in roll-based printing systems, and the phase-field method is shown to be an effective tool to simulate the liquid transport. In the phase-field simulations, the liquid transport through the ink transfer rollers is approximated as the stretching and splitting of liquid bridges with pinned or moving contact lines between vertically separating surfaces. First, the effect of the phase-field parameters and the mesh characteristics on the simulation results is examined. The simulation results show that a sharp interface limit is approached as the capillary width decreases while keeping the mobility proportional to the capillary width squared. Close to the sharp interface limit, the mobility changes over a specified range are observed to have no significant influence on the simulation results. Next, the ink transfer from the cells on the surface of an ink-metering roller to the surface of stamp features is simulated. Under negligible inertial effects and in the absence of gravity, the amount of liquid ink transferred from an axisymmetric cell with low surface wettability to a stamp with high surface wettability is found to increase as the cell sidewall steepness and the cell surface wettability decrease and the stamp surface wettability and the capillary number increase. Strategies for improving the resolution and quality of roll-based printing are derived based on an analysis of the simulation results. The application of novel materials that contain cells with irregular surface topography to stamp inking in high-resolution roll-based printing is assessed.

Field testing the Raman gas composition sensor for gas turbine operation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buric, M.; Chorpening, B.; Mullem, J.

2012-01-01

A gas composition sensor based on Raman spectroscopy using reflective metal lined capillary waveguides is tested under field conditions for feed-forward applications in gas turbine control. The capillary waveguide enables effective use of low powered lasers and rapid composition determination, for computation of required parameters to pre-adjust burner control based on incoming fuel. Tests on high pressure fuel streams show sub-second time response and better than one percent accuracy on natural gas fuel mixtures. Fuel composition and Wobbe constant values are provided at one second intervals or faster. The sensor, designed and constructed at NETL, is packaged for Class Imore » Division 2 operations typical of gas turbine environments, and samples gas at up to 800 psig. Simultaneous determination of the hydrocarbons methane, ethane, and propane plus CO, CO₂, H₂O, H₂, N₂, and O₂ are realized. The capillary waveguide permits use of miniature spectrometers and laser power of less than 100 mW. The capillary dimensions of 1 m length and 300 μm ID also enable a full sample exchange in 0.4 s or less at 5 psig pressure differential, which allows a fast response to changes in sample composition. Sensor operation under field operation conditions will be reported.« less

Liquid Level Sensing System

NASA Technical Reports Server (NTRS)

Korman, Valentin (Inventor); Wiley, John T. (Inventor); Duffell, Amanda G. (Inventor)

2014-01-01

A liquid level sensing system includes waveguides disposed in a liquid and distributed along a path with a gap between adjacent waveguides. A source introduces electromagnetic energy into the waveguides at a first end of the path. A portion of the electromagnetic energy exits the waveguides at a second end of the path. A detector measures the portion of the electromagnetic energy exiting the second end of the path.

Waveguide detection of right-angle-scattered light in flow cytometry

DOEpatents

Mariella, Jr., Raymond P.

2000-01-01

A transparent flow cell is used as an index-guided optical waveguide. A detector for the flow cell but not the liquid stream detects the Right-Angle-Scattered (RAS) Light exiting from one end of the flow cell. The detector(s) could view the trapped RAS light from the flow cell either directly or through intermediate optical light guides. If the light exits one end of the flow cell, then the other end of the flow cell can be given a high-reflectivity coating to approximately double the amount of light collected. This system is more robust in its alignment than the traditional flow cytometry systems which use imaging optics, such as microscope objectives.

Chemical Properties of Brown Carbon Aerosol Generated at the Missoula Fire Sciences Laboratory

NASA Astrophysics Data System (ADS)

Washenfelder, R. A.; Womack, C.; Franchin, A.; Middlebrook, A. M.; Wagner, N.; Manfred, K.

2017-12-01

Aerosol scattering and absorption are still among the largest uncertainties in quantifying radiative forcing. Biomass burning is a major source of light-absorbing carbonaceous aerosol in the United States. These aerosol are generally classified into two categories: black carbon (graphitic-like aerosol that absorbs broadly across the ultraviolet and visible spectral regions) and brown carbon (organic aerosol that absorbs strongly in the ultraviolet and near-visible spectral regions). The composition, volatility, and chemical aging of brown carbon are poorly known, but are important to understanding its radiative effects. We deployed three novel instruments to the Missoula Fire Sciences Laboratory in 2016 to measure brown carbon absorption: a photoacoustic spectrometer, broadband cavity enhanced spectrometer, and particle-into-liquid sampler coupled to a liquid waveguide capillary cell. The instruments sampled from a shared inlet with well-characterized dilution and thermal denuding. We sampled smoke from 32 controlled burns of fuels relevant to western U.S. wildfires. We use these measurements to determine the volatility of water-soluble brown carbon, and compare this to the volatility of water-soluble organic aerosol and total organic aerosol. We further examine the wavelength-dependence of the water-soluble brown carbon absorption as a function of denuder temperature. Together this gives new information about the solubility, volatility, and chemical composition of brown carbon.

Versatile microanalytical system with porous polypropylene capillary membrane for calibration gas generation and trace gaseous pollutants sampling applied to the analysis of formaldehyde, formic acid, acetic acid and ammonia in outdoor air.

PubMed

Coelho, Lúcia H G; Melchert, Wanessa R; Rocha, Flavio R; Rocha, Fábio R P; Gutz, Ivano G R

2010-11-15

The analytical determination of atmospheric pollutants still presents challenges due to the low-level concentrations (frequently in the μg m(-3) range) and their variations with sampling site and time. In this work, a capillary membrane diffusion scrubber (CMDS) was scaled down to match with capillary electrophoresis (CE), a quick separation technique that requires nothing more than some nanoliters of sample and, when combined with capacitively coupled contactless conductometric detection (C(4)D), is particularly favorable for ionic species that do not absorb in the UV-vis region, like the target analytes formaldehyde, formic acid, acetic acid and ammonium. The CMDS was coaxially assembled inside a PTFE tube and fed with acceptor phase (deionized water for species with a high Henry's constant such as formaldehyde and carboxylic acids, or acidic solution for ammonia sampling with equilibrium displacement to the non-volatile ammonium ion) at a low flow rate (8.3 nL s(-1)), while the sample was aspirated through the annular gap of the concentric tubes at 2.5 mL s(-1). A second unit, in all similar to the CMDS, was operated as a capillary membrane diffusion emitter (CMDE), generating a gas flow with know concentrations of ammonia for the evaluation of the CMDS. The fluids of the system were driven with inexpensive aquarium air pumps, and the collected samples were stored in vials cooled by a Peltier element. Complete protocols were developed for the analysis, in air, of NH(3), CH(3)COOH, HCOOH and, with a derivatization setup, CH(2)O, by associating the CMDS collection with the determination by CE-C(4)D. The ammonia concentrations obtained by electrophoresis were checked against the reference spectrophotometric method based on Berthelot's reaction. Sensitivity enhancements of this reference method were achieved by using a modified Berthelot reaction, solenoid micro-pumps for liquid propulsion and a long optical path cell based on a liquid core waveguide (LCW). All techniques and methods of this work are in line with the green analytical chemistry trends. Copyright © 2010 Elsevier B.V. All rights reserved.

Influence of granulometry in the Hurst exponent of air liquid interfaces formed during capillary rising in a granular media

NASA Astrophysics Data System (ADS)

Gontijo, Guilherme L.; Souza, Flávia B.; Braga, Rafael M. L.; Silva, Pedro H. E.; Correia, Maury D.; Atman, A. P. F.

2017-06-01

We report results concerning the fractal dimension of a air/fluid interface formed during the capillary rising of a fluid into a dense granular media. The system consists in a modified Hele-Shaw cell filled with grains at different granulometries and confined in a narrow gap between the glass plates. The system is then placed onto a water reservoir, and the liquid penetrates the medium due to capillary forces. We measure the Hurst exponent of the liquid/air interface with help of image processing, and follow the temporal evolution of the profiles. We observe that the Hurst exponent can be related with the granulometry, but the range of values are odd to the predicted values from models or theory.

Optical biosensors for cell adhesion.

PubMed

Ramsden, Jeremy J; Horvath, Robert

2009-01-01

Planar optical waveguides offer an ideal substratum for cells on which to reside. The materials from which the waveguides are made--high refractive index transparent dielectrics--correspond to the coatings of medical implants (e.g., the oxides of niobium, tantalum, and titanium) or the high molecular weight polymers used for culture flasks (e.g., polystyrene). The waveguides can furthermore be modified both chemically and morphologically while retaining their full capability for generating an evanescent optical field that has its greatest strength at the interface between the solid substratum and the liquid phase with which it is invariably in contact (i.e., the culture medium bathing the cells), decaying exponentially perpendicular to the interface at a rate controllable by varying the material parameters of the waveguide. Analysis of the perturbation of the evanescent field by the presence of living cells within it enables their size, number density, shape, refractive index (linked to their constitution) and so forth to be determined, the number of parameters depending on the number of waveguide lightmodes analyzed. No labeling of any kind is necessary, and convenient measurement setups are fully compatible with maintaining the cells in their usual environment. If the temporal evolution of the perturbation is analyzed, even more information can be obtained, such as the amount of material (microexudate) secreted by the cell while residing on the surface. Separation of parallel effects simultaneously contributing to the perturbation of the evanescent field can be accomplished by analysis of coupling peak shape when a grating coupler is used to measure the propagation constants of the waveguide lightmodes.

Dynamics and density distributions in a capillary-discharge waveguide with an embedded supersonic jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matlis, N. H., E-mail: nmatlis@gmail.com; Gonsalves, A. J.; Steinke, S.

We present an analysis of the gas dynamics and density distributions within a capillary-discharge waveguide with an embedded supersonic jet. This device provides a target for a laser plasma accelerator which uses longitudinal structuring of the gas-density profile to enable control of electron trapping and acceleration. The functionality of the device depends sensitively on the details of the density profile, which are determined by the interaction between the pulsed gas in the jet and the continuously-flowing gas in the capillary. These dynamics are captured by spatially resolving recombination light from several emission lines of the plasma as a function ofmore » the delay between the jet and the discharge. We provide a phenomenological description of the gas dynamics as well as a quantitative evaluation of the density evolution. In particular, we show that the pressure difference between the jet and the capillary defines three regimes of operation with qualitatively different longitudinal density profiles and show that jet timing provides a sensitive method for tuning between these regimes.« less

Multi Reflection of Lamb Wave Emission in an Acoustic Waveguide Sensor

PubMed Central

Schmitt, Martin; Olfert, Sergei; Rautenberg, Jens; Lindner, Gerhard; Henning, Bernd; Reindl, Leonhard Michael

2013-01-01

Recently, an acoustic waveguide sensor based on multiple mode conversion of surface acoustic waves at the solid—liquid interfaces has been introduced for the concentration measurement of binary and ternary mixtures, liquid level sensing, investigation of spatial inhomogenities or bubble detection. In this contribution the sound wave propagation within this acoustic waveguide sensor is visualized by Schlieren imaging for continuous and burst operation the first time. In the acoustic waveguide the antisymmetrical zero order Lamb wave mode is excited by a single phase transducer of 1 MHz on thin glass plates of 1 mm thickness. By contact to the investigated liquid Lamb waves propagating on the first plate emit pressure waves into the adjacent liquid, which excites Lamb waves on the second plate, what again causes pressure waves traveling inside the liquid back to the first plate and so on. The Schlieren images prove this multi reflection within the acoustic waveguide, which confirms former considerations and calculations based on the receiver signal. With this knowledge the sensor concepts with the acoustic waveguide sensor can be interpreted in a better manner. PMID:23447010

Multi reflection of Lamb wave emission in an acoustic waveguide sensor.

PubMed

Schmitt, Martin; Olfert, Sergei; Rautenberg, Jens; Lindner, Gerhard; Henning, Bernd; Reindl, Leonhard Michael

2013-02-27

Recently, an acoustic waveguide sensor based on multiple mode conversion of surface acoustic waves at the solid-liquid interfaces has been introduced for the concentration measurement of binary and ternary mixtures, liquid level sensing, investigation of spatial inhomogenities or bubble detection. In this contribution the sound wave propagation within this acoustic waveguide sensor is visualized by Schlieren imaging for continuous and burst operation the first time. In the acoustic waveguide the antisymmetrical zero order Lamb wave mode is excited by a single phase transducer of 1 MHz on thin glass plates of 1 mm thickness. By contact to the investigated liquid Lamb waves propagating on the first plate emit pressure waves into the adjacent liquid, which excites Lamb waves on the second plate, what again causes pressure waves traveling inside the liquid back to the first plate and so on. The Schlieren images prove this multi reflection within the acoustic waveguide, which confirms former considerations and calculations based on the receiver signal. With this knowledge the sensor concepts with the acoustic waveguide sensor can be interpreted in a better manner.

The 1- to 4-K refrigeration techniques for cooling masers on a beam waveguide antenna

NASA Technical Reports Server (NTRS)

Johnson, D. L.

1986-01-01

The status of technology is reported for various 1- to 4-K commercially available refrigeration systems capable of producing 1.5-K refrigeration to cool masers and superconducting cavity oscillators on the proposed beam waveguide antenna. The design requirements for the refrigeration system and the cryostat are presented. A continuously operating evaporation refrigerator that uses capillary tubing to provide a continuous, self-regulating flow of helium at approximately 1.5 K has been selected as the first refrigerator design for the beam waveguide antenna.

A tunable optofluidic circular liquid fiber

NASA Astrophysics Data System (ADS)

Li, Lei; Wu, Wei; Shi, Yang; Gong, Enze; Yang, Yi

2016-01-01

This paper presents a tunable optofluidic circular liquid fiber through the numerical simulation. Fiber is a significant optical device and has been widely applied on optical fiber communication. But the fiber based solid has limited tunability. Compared to solid fiber, the fiber based liquid material is relatively infrequent. Cause for the liquid optical device has more freedom tunable properties than solid counterpart, it has attracted more interest. The traditional optofluidic waveguide is designed like a sandwich in planar channel. This two-dimensional (2D) structure liquid waveguide will face huge transmission loss in the perpendicular direction of the flow streams. In this paper, a curving microchannel is designed inside the microchip to produce centrifugal effect. Two different liquids are injected into the chip by external pumps. In a particular situation, the core flow will be totally surrounded by the cladding flow. So the liquid can form an optical waveguide. Its structure is similar to an optical fiber which high refractive index (RI) liquid is core of the waveguide and the low RI liquid is cladding of the waveguide. Profit from the reconfigurability of liquid material, this liquid fiber has excellent tunability. The diameter of the core flow can be tuned in a wider range by changing the volume ratio of the flows through the finite element analysis. It is predictable that such a tunable liquid fiber may find wider applications in lab-on-a-chip systems and integrated optical devices.

Light propagation in the micro-size capillary injected by high temperature liquid

NASA Astrophysics Data System (ADS)

Li, Yan-jun; Li, Edward; Xiao, Hai

2016-11-01

The high temperature liquid is injected into the micro-size capillary and its light propagation behavior is investigated. We focus on two different liquid pumping methods. The first method can pump the high temperature liquid tin into the micro-size capillary by using a high pressure difference system. After pumping, a single mode fiber (SMF) connected with the optical carrier based microwave interferometry (OCMI) system is used to measure different liquid tin levels in the micro-size capillary. The second method can pump the room temperature engine oil into the capillary by using a syringe pump. This method can avoid the air bubbles when the liquids are pumped into the capillary.

Measurement of the refractive index of microquantity liquid filled in a capillary and a capillary wall without destruction.

PubMed

Li, Qiang; Pu, Xiaoyun

2013-07-20

A method for measuring the refractive index (RI) of a small volume of liquid and a capillary wall is presented in this paper. A transparent capillary filled with liquid is used as a cylindrical positive lens; subsequently, the focal length of the lens is derived through the base of paraxial approximation, which is recorded as a function of the RIs of the liquid and capillary wall. With the RI of a capillary wall known, the RI of the liquid can be obtained by measuring the focal length of the lens, which is characterized by a microquantity liquid, spatial resolution, and easy operation. The RI of the capillary wall can be calculated without ruining the capillary if the capillary is filled with a standard liquid (RI is known), the deviation of which is less than 0.003 RIU. The factors affecting accuracy of the measurement, for instance, the depth of a field (DOF) in a reading microscope system and the outer and inner diameters of a capillary are analyzed, while illustrating that the effective DOF plays an essential role in accurate measurement.

Modeling of Slot Waveguide Sensors Based on Polymeric Materials

PubMed Central

Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

2011-01-01

Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

Optofluidic waveguides: I. Concepts and implementations

PubMed Central

Schmidt, Holger; Hawkins, Aaron R.

2011-01-01

We review recent developments and current status of liquid-core optical waveguides in optofluidics with emphasis on suitability for creating fully planar optofluidic labs-on-a-chip. In this first of two contributions, we give an overview of the different waveguide types that are being considered for effectively combining micro and nanofluidics with integrated optics. The large number of approaches is separated into conventional index-guided waveguides and more recent implementations using wave interference. The underlying principle for waveguiding and the current status are described for each type. We then focus on reviewing recent work on microfabricated liquid-core antiresonant reflecting optical (ARROW) waveguides, including the development of intersecting 2D waveguide networks and optical fluorescence and Raman detection with planar beam geometry. Single molecule detection capability and addition of electrical control for electrokinetic manipulation and analysis of single bioparticles are demonstrated. The demonstrated performance of liquid-core ARROWs is representative of the potential of integrated waveguides for on-chip detection with ultrahigh sensitivity, and points the way towards the next generation of high-performance, low-cost and portable biomedical instruments. PMID:21442048

Reconfigurable modified surface layers using plasma capillaries around the neutral inclusion regime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Varault, S.; Universite Paul Sabatier—CNRS-Laplace 118, Route de Narbonne, F-31062 Toulouse Cedex 9; Gabard, B.

We show both theoretically and experimentally reconfigurable properties achieved by plasma inclusions placed in modified surface layers generally used to tailor the transmission and beaming properties of electromagnetic bandgap based waveguiding structures. A proper parametrization of the plasma capillaries allows to reach the neutral inclusion regime, where the inclusions appear to be electromagnetically transparent, letting the surface mode characteristics unaltered. Varying the electron density of the plasma inclusions provoques small perturbations around this peculiar regime, and we observe significant modifications of the transmission/beaming properties. This offers a way to dynamically select the enhanced transmission frequency or to modify the radiationmore » pattern of the structure, depending on whether the modified surface layer is placed at the entrance/exit of the waveguide.« less

Pore-scale modeling of Capillary Penetration of Wetting Liquid into 3D Fibrous Media: A Critical Examination of Equivalent Capillary Concept

NASA Astrophysics Data System (ADS)

Palakurthi, Nikhil Kumar; Ghia, Urmila; Comer, Ken

2013-11-01

Capillary penetration of liquid through fibrous porous media is important in many applications such as printing, drug delivery patches, sanitary wipes, and performance fabrics. Historically, capillary transport (with a distinct liquid propagating front) in porous media is modeled using capillary-bundle theory. However, it is not clear if the capillary model (Washburn equation) describes the fluid transport in porous media accurately, as it assumes uniformity of pore sizes in the porous medium. The present work investigates the limitations of the applicability of the capillary model by studying liquid penetration through virtual fibrous media with uniform and non-uniform pore-sizes. For the non-uniform-pore fibrous medium, the effective capillary radius of the fibrous medium was estimated from the pore-size distribution curve. Liquid penetration into the 3D virtual fibrous medium at micro-scale was simulated using OpenFOAM, and the numerical results were compared with the Washburn-equation capillary-model predictions. Preliminary results show that the Washburn equation over-predicts the height rise in the early stages (purely inertial and visco-inertial stages) of capillary transport.

Numerical Simulations of Crystal Growth of an Alloy Under Microgravity Conditions

NASA Technical Reports Server (NTRS)

Simpson, James E.; deGroh, Henry C., III; Garimella, Suresh V.; Abbaschian, Reza

1999-01-01

The directional solidification of a dilute binary alloy (Bi-1.0 at.%Sn)is investigated. Results are obtained at a gravity level of I pg. Computations are performed in two dimensions with a fixed, non-uniform grid. The simulation involves a solution of the species concentration equation (modified to account for solute rejection at the interface) and energy equation (modified to account for phase-change) for both the solid and liquid phases, in addition to the constitutive equations for describing convective flow in the melt. The effects of conductive heat transfer in the ampoule and in a capillary tube in the sample are included. To gauge the effects of including this growth capillary tube in the apparatus, simulations both with and without the capillary tube are presented and compared. Fully transient simulations have been performed; no simplifying steady-state approximations are used, however, the influence of solute on the melting temperature at the interface is not included. Both thermal and solutal convective cells are seen to form. Convective velocities are significantly damped inside the capillary, causing less segregation due to convection. As solidification proceeds beyond the capillary tube, longitudinal segregation arises as a result of the change in cross-sectional area of solidifying material. The magnitudes of the velocities in this cell increase significantly once the solid/liquid front passes beyond the end of the capillary tube; this causes a corresponding increase in the level of radial solute segregation in the solidified material.

Field Test Report: NETL Portable Raman Gas Composition Monitor - Initial Industrial tests at NETL and General Electric (GE)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael, Buric; Jessica, Mullen; Steven, Woodruff

2012-02-24

NETL has developed new technology which enables the use of Raman spectroscopy in the real-time measurement of gas mixtures. This technology uses a hollow reflective metal-lined capillary waveguide as a gas sampling cell which contains the sample gas, and efficiently collects optical Raman scattering from the gas sample, for measurement with a miniature spectrometer. The result is an optical Raman “fingerprint” for each gas which is tens or hundreds of times larger than that which can be collected with conventional free-space optics. In this manner, the new technology exhibits a combination of measurement speed and accuracy which is unprecedented formore » spontaneous Raman measurements of gases. This makes the system especially well-suited to gas turbine engine control based on a-priori measurement of incoming fuel composition. The system has been developed to produce a measurement of all of the common components of natural gas, including the lesser nitrogen, oxygen, carbon-dioxide, and carbon monoxide diluents to better than 1% concentration accuracy each second. The objective of this task under CRADA 10-N100 was to evaluate the capability of a laser Raman capillary gas sensor for combustion fuels. A portable version of the Raman gas sensor, constructed at NETL, was used for field-trials conducted in a cooperative research effort at a GE facility. Testing under the CRADA was performed in 5 parts. Parts 1-4 were successful in testing of the Raman Gas Composition Monitor with bottled calibration gases, and in continuous monitoring of several gas streams at low pressure, in comparison with an online mass spectrometer. In part 5, the Raman Gas Composition Monitor was moved outdoors for testing with high pressure gas supplies. Some difficulties were encountered during industrial testing including the condensation of heavy hydrocarbons inside the sample cell (in part 5), communication with the GE data collection system, as well as some drift in the optical noise background. The difficulties with liquid contaminants will be overcome through the use of prodigious sample-cell heating and additional line filtration including liquid ingress-protection. The communication problem was resolved through site-specific troubleshooting of the MODBUS data tags.« less

Fuel flexibility via real-time Raman fuel-gas analysis for turbine system control

NASA Astrophysics Data System (ADS)

Buric, M.; Woodruff, S.; Chorpening, B.; Tucker, D.

2015-06-01

The modern energy production base in the U.S. is increasingly incorporating opportunity fuels such as biogas, coalbed methane, coal syngas, solar-derived hydrogen, and others. In many cases, suppliers operate turbine-based generation systems to efficiently utilize these diverse fuels. Unfortunately, turbine engines are difficult to control given the varying energy content of these fuels, combined with the need for a backup natural gas supply to provide continuous operation. Here, we study the use of a specially designed Raman Gas Analyzer based on capillary waveguide technology with sub-second response time for turbine control applications. The NETL Raman Gas Analyzer utilizes a low-power visible pump laser, and a capillary waveguide gas-cell to integrate large spontaneous Raman signals, and fast gas-transfer piping to facilitate quick measurements of fuel-gas components. A U.S. Department of Energy turbine facility known as HYPER (hybrid performance system) serves as a platform for apriori fuel composition measurements for turbine speed or power control. A fuel-dilution system is used to simulate a compositional upset while simultaneously measuring the resultant fuel composition and turbine response functions in real-time. The feasibility and efficacy of system control using the spontaneous Raman-based measurement system is then explored with the goal of illustrating the ability to control a turbine system using available fuel composition as an input process variable.

Quantum dot enabled detection of Escherichia coli using a cell-phone†

PubMed Central

Zhu, Hongying; Sikora, Uzair; Ozcan, Aydogan

2013-01-01

We report a cell-phone based Escherichia coli (E. coli) detection platform for screening of liquid samples. In this compact and cost-effective design attached to a cell-phone, we utilize anti-E. coli O157:H7 antibody functionalized glass capillaries as solid substrates to perform a quantum dot based sandwich assay for specific detection of E. coli O157:H7 in liquid samples. Using battery-powered inexpensive light-emitting-diodes (LEDs) we excite/pump these labelled E. coli particles captured on the capillary surface, where the emission from the quantum dots is then imaged using the cell-phone camera unit through an additional lens that is inserted between the capillary and the cell-phone. By quantifying the fluorescent light emission from each capillary tube, the concentration of E. coli in the sample is determined. We experimentally confirmed the detection limit of this cell-phone based fluorescent imaging and sensing platform as ~5 to 10 cfu mL−1 in buffer solution. We also tested the specificity of this E. coli detection platform by spiking samples with different species (e.g., Salmonella) to confirm that non-specific binding/detection is negligible. We further demonstrated the proof-of-concept of our approach in a complex food matrix, e.g., fat-free milk, where a similar detection limit of ~5 to 10 cfu mL−1 was achieved despite challenges associated with the density of proteins that exist in milk. Our results reveal the promising potential of this cell-phone enabled field-portable and cost-effective E. coli detection platform for e.g., screening of water and food samples even in resource limited environments. The presented platform can also be applicable to other pathogens of interest through the use of different antibodies. PMID:22396952

Quantum dot enabled detection of Escherichia coli using a cell-phone.

PubMed

Zhu, Hongying; Sikora, Uzair; Ozcan, Aydogan

2012-06-07

We report a cell-phone based Escherichia coli (E. coli) detection platform for screening of liquid samples. In this compact and cost-effective design attached to a cell-phone, we utilize anti-E. coli O157:H7 antibody functionalized glass capillaries as solid substrates to perform a quantum dot based sandwich assay for specific detection of E. coli O157:H7 in liquid samples. Using battery-powered inexpensive light-emitting-diodes (LEDs) we excite/pump these labelled E. coli particles captured on the capillary surface, where the emission from the quantum dots is then imaged using the cell-phone camera unit through an additional lens that is inserted between the capillary and the cell-phone. By quantifying the fluorescent light emission from each capillary tube, the concentration of E. coli in the sample is determined. We experimentally confirmed the detection limit of this cell-phone based fluorescent imaging and sensing platform as ∼5 to 10 cfu mL(-1) in buffer solution. We also tested the specificity of this E. coli detection platform by spiking samples with different species (e.g., Salmonella) to confirm that non-specific binding/detection is negligible. We further demonstrated the proof-of-concept of our approach in a complex food matrix, e.g., fat-free milk, where a similar detection limit of ∼5 to 10 cfu mL(-1) was achieved despite challenges associated with the density of proteins that exist in milk. Our results reveal the promising potential of this cell-phone enabled field-portable and cost-effective E. coli detection platform for e.g., screening of water and food samples even in resource limited environments. The presented platform can also be applicable to other pathogens of interest through the use of different antibodies.

Surface-directed capillary system; theory, experiments and applications.

PubMed

Bouaidat, Salim; Hansen, Ole; Bruus, Henrik; Berendsen, Christian; Bau-Madsen, Niels Kristian; Thomsen, Peter; Wolff, Anders; Jonsmann, Jacques

2005-08-01

We present a capillary flow system for liquid transport in microsystems. Our simple microfluidic system consists of two planar parallel surfaces, separated by spacers. One of the surfaces is entirely hydrophobic, the other mainly hydrophobic, but with hydrophilic pathways defined on it by photolithographic means. By controlling the wetting properties of the surfaces in this manner, the liquid can be confined to certain areas defined by the hydrophilic pathways. This technique eliminates the need for alignment of the two surfaces. Patterned plasma-polymerized hexafluoropropene constitutes the hydrophobic areas, whereas the untreated glass surface constitutes the hydrophilic pathways. We developed a theoretical model of the capillary flow and obtained analytical solutions which are in good agreement with the experimental results. The capillarity-driven microflow system was also used to pattern and immobilize biological material on planar substrates: well-defined 200 microm wide strips of human cells (HeLa) and fluorescence labelled proteins (fluorescein isothiocyanate-labelled bovine serum albumin, i.e., FITC-BSA) were fabricated using the capillary flow system presented here.

Derivation of Jurin's Law Revisited

ERIC Educational Resources Information Center

Rodriguez-Valverde, Miguel Angel; Miranda, Maria Tirado

2011-01-01

The capillary rise/fall of a liquid within a thin capillary tube is described by the well-established Jurin's law. The liquid reaches an equilibrium height/depth as the capillary pressure is balanced by the hydrostatic pressure. When the adhesion force at the three-phase contact line is counteracted by the liquid weight, the liquid column also…

A neuron-in-capillary platform for facile collection and mass spectrometric characterization of a secreted neuropeptide

PubMed Central

Lee, Chang Young; Fan, Yi; Rubakhin, Stanislav S.; Yoon, Sook; Sweedler, Jonathan V.

2016-01-01

The integration of microfluidic devices—which efficiently handle small liquid volumes—with separations/mass spectrometry (MS) is an effective approach for profiling the neurochemistry occurring in selected neurons. Interfacing the microfluidic cell culture to the mass spectrometer is challenging because of geometric and scaling issues. Here we demonstrate the hyphenation of a neuron-in-capillary platform to a solid phase extraction device and off-line MS. A primary neuronal culture of Aplysia californica neurons was established directly inside a cylindrical polyimide capillary. The approach also uses a particle-embedded monolith to condition neuropeptide releasates collected from several Aplysia neurons cultured in the capillary, with the subsequent characterization of released peptides via MS. This system presents a number of advances compared to more traditional microfluidic devices fabricated with polydimethylsiloxane. These include low cost, easy access to cell culture, rigidity, ease of transport, and minimal fluid handling. The cylindrical geometry of the platform allows convenient interface with a wide range of analytical tools that utilize capillary columns. PMID:27245782

Liquid jet response to internal modulated ultrasonic radiation pressure and stimulated drop production.

PubMed

Lonzaga, Joel B; Osterhoudt, Curtis F; Thiessen, David B; Marston, Philip L

2007-06-01

Experimental evidence shows that a liquid jet in air is an acoustic waveguide having a cutoff frequency inversely proportional to the jet diameter. Ultrasound applied to the jet supply liquid can propagate within the jet when the acoustic frequency is near to or above the cutoff frequency. Modulated radiation pressure is used to stimulate large amplitude deformations and the breakup of the jet into drops. The jet response to the modulated internal ultrasonic radiation pressure was monitored along the jet using (a) an optical extinction method and (b) images captured by a video camera. The jet profile oscillates at the frequency of the radiation pressure modulation and where the response is small, the amplitude was found to increase in proportion to the square of the acoustic pressure amplitude as previously demonstrated for oscillating drops [P.L. Marston and R.E. Apfel, J. Acoust. Soc. Am. 67, 27-37 (1980)]. Small amplitude deformations initially grow approximately exponentially with axial distance along the jet. Though aspects of the perturbation growth can be approximated from Rayleigh's analysis of the capillary instability, some detailed features of the observed jet response to modulated ultrasound are unexplained neglecting the effects of gravity.

Capillary pumping independent of the liquid surface energy and viscosity

NASA Astrophysics Data System (ADS)

Guo, Weijin; Hansson, Jonas; van der Wijngaart, Wouter

2018-03-01

Capillary pumping is an attractive means of liquid actuation because it is a passive mechanism, i.e., it does not rely on an external energy supply during operation. The capillary flow rate generally depends on the liquid sample viscosity and surface energy. This poses a problem for capillary-driven systems that rely on a predictable flow rate and for which the sample viscosity or surface energy are not precisely known. Here, we introduce the capillary pumping of sample liquids with a flow rate that is constant in time and independent of the sample viscosity and sample surface energy. These features are enabled by a design in which a well-characterized pump liquid is capillarily imbibed into the downstream section of the pump and thereby pulls the unknown sample liquid into the upstream pump section. The downstream pump geometry is designed to exert a Laplace pressure and fluidic resistance that are substantially larger than those exerted by the upstream pump geometry on the sample liquid. Hence, the influence of the unknown sample liquid on the flow rate is negligible. We experimentally tested pumps of the new design with a variety of sample liquids, including water, different samples of whole blood, different samples of urine, isopropanol, mineral oil, and glycerol. The capillary filling speeds of these liquids vary by more than a factor 1000 when imbibed to a standard constant cross-section glass capillary. In our new pump design, 20 filling tests involving these liquid samples with vastly different properties resulted in a constant volumetric flow rate in the range of 20.96-24.76 μL/min. We expect this novel capillary design to have immediate applications in lab-on-a-chip systems and diagnostic devices.

High-sensitivity liquid refractive-index sensor based on a Mach-Zehnder interferometer with a double-slot hybrid plasmonic waveguide.

PubMed

Sun, Xu; Dai, Daoxin; Thylén, Lars; Wosinski, Lech

2015-10-05

A Mach-Zehnder Interferometer (MZI) liquid sensor, employing ultra-compact double-slot hybrid plasmonic (DSHP) waveguide as active sensing arm, is developed. Numerical results show that extremely large optical confinement factor of the tested analytes (as high as 88%) can be obtained by DSHP waveguide with optimized geometrical parameters, which is larger than both, conventional SOI waveguides and plasmonic slot waveguides with same widths. As for MZI sensor with 40μm long DSHP active sensing area, the sensitivity can reach as high value as 1061nm/RIU (refractive index unit). The total loss, excluding the coupling loss of the grating coupler, is around 4.5dB.

Van der waals forces on thin liquid films in capillary tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herdt, G.C.; Swanson, L.W.

1993-10-01

A theory of the van der Waals attraction between a thin liquid films and a capillary tube is presented assuming the presence of a vapor-liquid interface. The model is based on the surface mode analysis method of van Kampen et al. Values for the van der Waals interaction energy per unit area were calculated for liquid films of pentane on a gold substrate assuming a thin liquid film. Results indicate that the effect of capillary curvature on the van der Waals interaction increases as the ratio of the liquid film thickness to the capillary radius is increased. This trend ismore » consistent with predictions based on the Hamaker theory. Deviations from results based on the Hamaker theory are easily explained in terms of retardation of the van der Waals interaction. Because the effect of capillary curvature increases in the regime where retardation effects become important, curvature effects constitute a small correction to the van der Waals forces in a capillary tube.« less

Capillary Pressure of a Liquid Between Uniform Spheres Arranged in a Square-Packed Layer

NASA Technical Reports Server (NTRS)

Alexader, J. Iwan D.; Slobozhanin, Lev A.; Collicott, Steven H.

2004-01-01

The capillary pressure in the pores defined by equidimensional close-packed spheres is analyzed numerically. In the absence of gravity the menisci shapes are constructed using Surface Evolver code. This permits calculation the free surface mean curvature and hence the capillary pressure. The dependences of capillary pressure on the liquid volume constructed here for a set of contact angles allow one to determine the evolution of basic capillary characteristics under quasi-static infiltration and drainage. The maximum pressure difference between liquid and gas required for a meniscus passing through a pore is calculated and compared with that for hexagonal packing and with approximate solution given by Mason and Morrow [l]. The lower and upper critical liquid volumes that determine the stability limits for the equilibrium capillary liquid in contact with square packed array of spheres are tabulated for a set of contact angles.

Planar polymer waveguides with a graded-index profile resulting from intermixing of methacrylates in closed microchannels

NASA Astrophysics Data System (ADS)

Missinne, Jeroen; Misseeuw, Lara; Liu, Xiang; Salter, Patrick S.; Van Steenberge, Geert; Adesanya, Kehinde; Van Vlierberghe, Sandra; Booth, Martin J.; Dubruel, Peter

2018-02-01

Graded-index waveguides are known to exhibit lower losses and considerably larger bandwidths compared to step-index waveguides. The present work reports on a new concept for realizing such waveguides on a planar substrate by capillary filling microchannels (cladding) with monomer solution (core). A graded-index profile is obtained by intermixing between the core and cladding material at the microchannel interface. To this end, various ratios of methyl methacrylate (MMA) and octafluoropentyl methacrylate (OFPMA) were evaluated as starting monomers and the results showed that the polymers P50:50 (50:50 MMA:OFPMA) and P0:100 (100% OFPMA) were suitable to be applied as waveguide core and cladding material respectively. Light guiding in the resulting P50:50/P0:100 waveguides was demonstrated and the refractive-index profile was quantified and compared with that of conventional step-index waveguides. The results for both cases were clearly different and a gradual refractive index transition between the core and cladding was found for the newly developed waveguides. Although the concept has been demonstrated in a research environment, it also has potential for upscaling by employing drop-on-demand dispensing of polymer waveguide material in pre-patterned microchannels, for example in a roll-to-roll environment.

Coherent random lasing from liquid waveguide gain channels with biological scatters

NASA Astrophysics Data System (ADS)

Zhang, Hong; Feng, Guoying; Wang, Shutong; Yang, Chao; Yin, Jiajia; Zhou, Shouhuan

2014-12-01

A unidirectional coherent random laser based on liquid waveguide gain channels with biological scatters is demonstrated. The optical feedback of the random laser is provided by both light scattering and waveguide confinement. This waveguide-scattering-feedback scheme not only reduces the pump threshold but also makes the output of random laser directional. The threshold of our random laser is about 11 μJ. The emission spectra can be sensitively tuned by changing pump position due to the micro/nano-scale randomness of butterfly wings. It shows the potential applications of optofluidic random lasers for bio-chemical sensors on-chip.

Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography.

PubMed

Tang, Sheng; Liu, Shujuan; Guo, Yong; Liu, Xia; Jiang, Shengxiang

2014-08-29

Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

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.

Interfacial tension measurement of immiscible liq uids using a capillary tube

NASA Technical Reports Server (NTRS)

Rashidnia, N.; Balasubramaniam, R.; Delsignore, D.

1992-01-01

The interfacial tension of immiscible liquids is an important thermophysical property that is useful in the behavior of liquids both in microgravity (Martinez et al. (1987) and Karri and Mathur (1988)) and in enhanced oil recovery processes under normal gravity (Slattery (1974)). Many techniques are available for its measurement, such as the ring method, drop weight method, spinning drop method, and capillary height method (Adamson (1960) and Miller and Neogi (1985)). Karri and Mathur mention that many of the techniques use equations that contain a density difference term and are inappropriate for equal density liquids. They reported a new method that is suitable for both equal and unequal density liquids. In their method, a capillary tube forms one of the legs of a U-tube. The interfacial tension is related to the heights of the liquids in the cups of the U-tube above the interface in the capillary. Our interest in this area arose from a need to measure small interfacial tension (around 1 mN/m) for a vegetable oil/silicon oil system that was used in a thermocapillary drop migration experiment (Rashidnia and Balasubramaniam (1991)). In our attempts to duplicate the method proposed by Karri and Mathur, we found it quite difficult to anchor the interface inside the capillary tube; small differences of the liquid heights in the cups drove the interface out of the capillary. We present an alternative method using a capillary tube to measure the interfacial tensions of liquids of equal or unequal density. The method is based on the combined capillary rises of both liquids in the tube.

Pleural liquid and its exchanges.

PubMed

Agostoni, Emilio; Zocchi, Luciano

2007-12-15

After an account on morphological features of visceral and parietal pleura, mechanical coupling between lung and chest wall is outlined. Volume of pleural liquid is considered along with its thickness in various regions, and its composition. Pleural liquid pressure (P(liq)) and pressure exerted by lung recoil in various species and postures are then compared, and the vertical gradient of P(liq) considered. Implications of lower P(liq) in the lung zone than in the costo-phrenic sinus at iso-height are pointed out. Mesothelial permeability to H(2)O, Cl(-), Na(+), mannitol, sucrose, inulin, albumin, and various size dextrans is provided, along with paracellular "pore" radius of mesothelium. Pleural liquid is produced by filtration from parietal pleura capillaries according to Starling forces. It is removed by absorption in visceral pleura capillaries according to Starling forces (at least in some species), lymphatic drainage through stomata of parietal mesothelium (essential to remove cells, particles, and large macromolecules), solute-coupled liquid absorption, and transcytosis through mesothelium.

Thermodynamics of Capillary Rise: Why Is the Meniscus Curved?

ERIC Educational Resources Information Center

Henriksson, Ulf; Eriksson, Jan Christer

2004-01-01

The thermodynamics of capillary rise is explained as the gravitational elevation of the whole column of liquid caused by the positive connection between the liquid, and the solid wall of the capillary tube. The curvature of the meniscus is ascribed to the maintenance of a physiochemical balance throughout the gravitational column of liquid.

A Capillary-Based Static Phase Separator for Highly Variable Wetting Conditions

NASA Technical Reports Server (NTRS)

Thomas, Evan A.; Graf, John C.; Weislogel, Mark M.

2010-01-01

The invention, a static phase separator (SPS), uses airflow and capillary wetting characteristics to passively separate a two-phase (liquid and air) flow. The device accommodates highly variable liquid wetting characteristics. The resultant design allows for a range of wetting properties from about 0 to over 90 advancing contact angle, with frequent complete separation of liquid from gas observed when using appropriately scaled test conditions. Additionally, the design accommodates a range of air-to-liquid flow-rate ratios from only liquid flow to over 200:1 air-to-liquid flow rate. The SPS uses a helix input section with an ice-cream-cone-shaped constant area cross section (see figure). The wedge portion of the cross section is on the outer edge of the helix, and collects the liquid via centripetal acceleration. The helix then passes into an increasing cross-sectional area vane region. The liquid in the helix wedge is directed into the top of capillary wedges in the liquid containment section. The transition from diffuser to containment section includes a 90 change in capillary pumping direction, while maintaining inertial direction. This serves to impinge the liquid into the two off-center symmetrical vanes by the airflow. Rather than the airflow serving to shear liquid away from the capillary vanes, the design allows for further penetration of the liquid into the vanes by the air shear. This is also assisted by locating the air exit ports downstream of the liquid drain port. Additionally, any droplets not contained in the capillary vanes are re-entrained downstream by a third opposing capillary vane, which directs liquid back toward the liquid drain port. Finally, the dual air exit ports serve to slow the airflow down, and to reduce the likelihood of shear. The ports are stove-piped into the cavity to form an unfriendly capillary surface for a wetting fluid to carryover. The liquid drain port is located at the start of the containment region, allowing for draining the bulk fluid in a continuous circuit. The functional operation of the SPS involves introducing liquid flow (from a human body, a syringe, or other source) to the two-phase inlet while an air fan pulls on the air exit lines. The fan is operated until the liquid is fully introduced. The system is drained by negative pressure on the liquid drain lines when the SPS containment system is full.

A magnetically tunable non-Bragg defect mode in a corrugated waveguide filled with liquid crystals

NASA Astrophysics Data System (ADS)

Zhang, Lu; Fan, Ya-Xian; Liu, Huan; Han, Xu; Lu, Wen-Qiang; Tao, Zhi-Yong

2018-04-01

A magnetically tunable, non-Bragg defect mode (NBDM) was created in the terahertz frequency range by inserting a defect in the middle of a periodically corrugated waveguide filled with liquid crystals (LCs). In the periodic waveguide, non-Bragg gaps beyond the Bragg ones, which appear in the transmission spectra, are created by different transverse mode resonances. The transmission spectra of the waveguide containing a defect showed that a defect mode was present inside the non-Bragg gap. The NBDM has quite different features compared to the Bragg defect mode, which includes more complex, high-order guided wave modes. In our study, we filled the corrugated waveguide with LCs to realize the tunability of the NBDM. The simulated results showed that the NBDM in a corrugated waveguide filled with LCs can be used in filters, sensors, switches, and other terahertz integrated devices.

Optofluidic waveguide as a transformation optics device for lightwave bending and manipulation.

PubMed

Yang, Y; Liu, A Q; Chin, L K; Zhang, X M; Tsai, D P; Lin, C L; Lu, C; Wang, G P; Zheludev, N I

2012-01-31

Transformation optics represents a new paradigm for designing light-manipulating devices, such as cloaks and field concentrators, through the engineering of electromagnetic space using materials with spatially variable parameters. Here we analyse liquid flowing in an optofluidic waveguide as a new type of controllable transformation optics medium. We show that a laminar liquid flow in an optofluidic channel exhibits spatially variable dielectric properties that support novel wave-focussing and interference phenomena, which are distinctively different from the discrete diffraction observed in solid waveguide arrays. Our work provides new insight into the unique optical properties of optofluidic waveguides and their potential applications.

Optimized Wavelength-Tuned Nonlinear Frequency Conversion Using a Liquid Crystal Clad Waveguide

NASA Technical Reports Server (NTRS)

Stephen, Mark A. (Inventor)

2018-01-01

An optimized wavelength-tuned nonlinear frequency conversion process using a liquid crystal clad waveguide. The process includes implanting ions on a top surface of a lithium niobate crystal to form an ion implanted lithium niobate layer. The process also includes utilizing a tunable refractive index of a liquid crystal to rapidly change an effective index of the lithium niobate crystal.

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.

Optical phased arrays with evanescently-coupled antennas

DOEpatents

Sun, Jie; Watts, Michael R; Yaacobi, Ami; Timurdogan, Erman

2015-03-24

An optical phased array formed of a large number of nanophotonic antenna elements can be used to project complex images into the far field. These nanophotonic phased arrays, including the nanophotonic antenna elements and waveguides, can be formed on a single chip of silicon using complementary metal-oxide-semiconductor (CMOS) processes. Directional couplers evanescently couple light from the waveguides to the nanophotonic antenna elements, which emit the light as beams with phases and amplitudes selected so that the emitted beams interfere in the far field to produce the desired pattern. In some cases, each antenna in the phased array may be optically coupled to a corresponding variable delay line, such as a thermo-optically tuned waveguide or a liquid-filled cell, which can be used to vary the phase of the antenna's output (and the resulting far-field interference pattern).

Modeling of the capillary wicking of flax fibers by considering the effects of fiber swelling and liquid absorption.

PubMed

Testoni, Guilherme Apolinario; Kim, Sihwan; Pisupati, Anurag; Park, Chung Hae

2018-09-01

We propose a new model for the capillary rise of liquid in flax fibers whose diameter is changed by liquid absorption. Liquid absorption into the flax fibers is taken into account in a new modified Washburn equation by considering the mass of the liquid absorbed inside the fibers as well as that imbibed between the fibers. The change of permeability and hydraulic radius of pores in a fibrous medium due to the fiber swelling is modeled by a statistical approach considering a non-uniform distribution of flax fiber diameter. By comparisons between capillary rise test results and modeling results, we prove the validity of the proposed modified Washburn model to take into account the effects from fiber swelling and liquid absorption on the decrease of capillary rise velocity. The experimental observation of long-term capillary rise tests show that the swelling behavior of the fibers highly packed in a closed volume and its influence on the capillary wicking are different from those of an individual single fiber in a free space. The current approach was useful to characterize the swelling of fibers highly packed in a closed volume and its influence of the long-term behavior of capillary wicking. Copyright © 2018 Elsevier Inc. All rights reserved.

Magneto-capillary valve for integrated purification and enrichment of nucleic acids and proteins.

PubMed

den Dulk, Remco C; Schmidt, Kristiane A; Sabatté, Gwénola; Liébana, Susana; Prins, Menno W J

2013-01-07

We describe the magneto-capillary valve (MCV) technology, a flexible approach for integrated biological sample preparation within the concept of stationary microfluidics. Rather than moving liquids in a microfluidic device, discrete units of liquid are present at fixed positions in the device and magnetic particles are actuated between the fluids. The MCV concept is characterized by the use of two planar surfaces at a capillary mutual distance, with specific features to confine the fluids by capillary forces, and the use of a gas or a phase-change material separating the stationary aqueous liquids. We have studied the physics of magneto-capillary valving by quantifying the magnetic force as a function of time and position, which reveals the balance of magnetic, capillary and frictional forces in the system. By purification experiments with a fluorescent tracer we have measured the amount of co-transported liquid, which is a key parameter for efficient purification. To demonstrate the versatility of the technology, several MCV device architectures were tested in a series of biological assays, showing the purification and enrichment of nucleic acids and proteins. Target recovery comparable to non-miniaturized commercial kits was observed for the extraction of DNA from human cells in buffer, using a device architecture with patterned air valves. Experiments using an enrichment module and patterned air valves demonstrate a 40-fold effective enrichment of DNA in buffer. DNA was also successfully purified from blood plasma using paraffin phase-change valves. Finally, the enrichment of a protein biomarker (prostate-specific antigen) using geometrical air valves resulted in a 7-fold increase of detection signal. The MCV technology is versatile, offers extensive freedom for the design of fully integrated systems, and is expected to be manufacturable in a cost-effective way. We conclude that the MCV technology can become an important enabling technology for point-of-care systems with sample in-result out performance.

Hollow waveguide cavity ringdown spectroscopy

NASA Technical Reports Server (NTRS)

Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

2012-01-01

Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

Three-Dimensional Simulation of Liquid Drop Dynamics Within Unsaturated Vertical Hele-Shaw Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hai Huang; Paul Meakin

A three-dimensional, multiphase fluid flow model with volume of fluid-interface tracking was developed and applied to study the multiphase dynamics of moving liquid drops of different sizes within vertical Hele-Shaw cells. The simulated moving velocities are significantly different from those obtained from a first-order analytical approximation, based on simple force-balance concepts. The simulation results also indicate that the moving drops can exhibit a variety of shapes and that the transition among these different shapes is largely determined by the moving velocities. More important, there is a transition from a linear moving regime at small capillary numbers, in which the capillarymore » number scales linearly with the Bond number, to a nonlinear moving regime at large capillary numbers, in which the moving drop releases a train of droplets from its trailing edge. The train of droplets forms a variety of patterns at different moving velocities.« less

Real-time redox speciation of iron in estuarine and coastal surface waters.

PubMed

Huang, Yongming; Yuan, Dongxing; Zhu, Yong; Feng, Sichao

2015-03-17

An automated, shipboard-use system was developed for real-time speciation of iron in coastal surface waters. It comprised a towed Fish underway sampler and a modified reverse flow injection analysis system with a liquid waveguide capillary flow cell-spectrophotometric detection device. The detection was based on the reaction between ferrozine and Fe(II). The detection limits of 0.3 and 0.7 nM were achieved for Fe(II) and Fe(II+III), together with their respective dynamic linear ranges of 0.5-250 and 0.9-250 nM. The system was successfully deployed and run consecutively for about 1 week during a cruise in August 2009 to the East China Sea off the Changjiang Estuary. The distribution of operationally defined field dissolvable Fe(II) and Fe(II+III) (expressed as Fea(II) and Fea(II+III)) in these areas was obtained, which showed that both Fea(II) and Fea(II+III) concentrations decreased with salinity when there were relatively high Fea(II) concentrations (up to about 120 nM) near shore. A distinct distribution of Fea(II) to Fea(II+III) ratios was also revealed, with a ratio of 0.58 in the water off Changjiang Estuary and 0.19 in the open ocean.

A multisyringe flow-based system for kinetic-catalytic determination of cobalt(II).

PubMed

Chaparro, Laura; Ferrer, Laura; Leal, Luz; Cerdà, Víctor

2015-02-01

A kinetic-catalytic method for cobalt determination based on the catalytic effect of cobalt(II) on the oxidative coupling of 1,2-dihydroxyanthraquinone (alizarin) was automated exploiting multisyringe flow injection analysis (MSFIA). The proposed method was performed at pH 9.2, resulting in a discoloration process in the presence of hydrogen peroxide. The fixed-time approach was employed for analytical signal measurement. The spectrophotometric detection was used exploiting a liquid waveguide capillary cell (LWCC), of 1m optical length at 465 nm. The optimization was carried out by a multivariate approach, reaching critical values of 124 µmol L(-1) and 0.22 mol L(-1) for alizarin and hydrogen peroxide, respectively, and 67°C of reagent temperature. A sample volume of 150 µL was used allowing a sampling rate of 30h(-1). Under optimal conditions, calibration curve was linear in the range of 1-200 µg L(-1) Co, achieving a DL of 0.3 µg L(-1) Co. The repeatability, expressed as relative standard deviation (RSD) was lower than 1%. The proposed analytical procedure was applied to the determination of cobalt in cobalt gluconate and different forms of vitamin B12, cyanocobalamin and hydroxicobalamin with successful results showing recoveries around 95%. Copyright © 2014 Elsevier B.V. All rights reserved.

A unique all-optic switch based on an innovatively designed liquid crystal waveguide

NASA Astrophysics Data System (ADS)

Nam, Sung-Hyun; Su, Wei-Hung; Chavez, Jesus; Yin, Shizhuo

2003-10-01

A unique, all-optic switch based on an innovatively designed planar lightwave circuit (PLC) is presented in this paper. The switching function is achieved by using ultra large birefringence of nematic liquid crystals (NLC) filled at the trench of waveguides. The trench at the crossing forms a waveguide mirror or a matching medium when extraordinary and ordinary refractive indices of NLC are employed, respectively. The major advantages of our unique design are: (1) the limitation that refractive index of liquid crystal must be less than that of waveguide material itself is eliminated so that conventional NCL material such as E7 can be used; (2) it is a self aligned fabrication process that alleviates the tight tolerance of later tilt error; (3) the design is thermally stable. The successful fabrication of this unqiue switch could result in an enabling element for the next generation all-optic networks.

Measurement of Capillary Radius and Contact Angle within Porous Media.

PubMed

Ravi, Saitej; Dharmarajan, Ramanathan; Moghaddam, Saeed

2015-12-01

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

Sensitivity Enhancement in Si Nanophotonic Waveguides Used for Refractive Index Sensing

PubMed Central

Shi, Yaocheng; Ma, Ke; Dai, Daoxin

2016-01-01

A comparative study is given for the sensitivity of several typical Si nanophotonic waveguides, including SOI (silicon-on-insulator) nanowires, nanoslot waveguides, suspended Si nanowires, and nanofibers. The cases for gas sensing (ncl ~ 1.0) and liquid sensing (ncl ~ 1.33) are considered. When using SOI nanowires (with a SiO2 buffer layer), the sensitivity for liquid sensing (S ~ 0.55) is higher than that for gas sensing (S ~ 0.35) due to lower asymmetry in the vertical direction. By using SOI nanoslot waveguides, suspended Si nanowires, and Si nanofibers, one could achieve a higher sensitivity compared to sensing with a free-space beam (S = 1.0). The sensitivity for gas sensing is higher than that for liquid sensing due to the higher index-contrast. The waveguide sensitivity of an optimized suspended Si nanowire for gas sensing is as high as 1.5, which is much higher than that of a SOI nanoslot waveguide. Furthermore, the optimal design has very large tolerance to the core width variation due to the fabrication error (∆w ~ ±50 nm). In contrast, a Si nanofiber could also give a very high sensitivity (e.g., ~1.43) while the fabrication tolerance is very small (i.e., ∆w < ±5 nm). The comparative study shows that suspended Si nanowire is a good choice to achieve ultra-high waveguide sensitivity. PMID:26950132

Sensitivity Enhancement in Si Nanophotonic Waveguides Used for Refractive Index Sensing.

PubMed

Shi, Yaocheng; Ma, Ke; Dai, Daoxin

2016-03-03

A comparative study is given for the sensitivity of several typical Si nanophotonic waveguides, including SOI (silicon-on-insulator) nanowires, nanoslot waveguides, suspended Si nanowires, and nanofibers. The cases for gas sensing (ncl ~ 1.0) and liquid sensing (ncl ~ 1.33) are considered. When using SOI nanowires (with a SiO₂ buffer layer), the sensitivity for liquid sensing (S ~ 0.55) is higher than that for gas sensing (S ~ 0.35) due to lower asymmetry in the vertical direction. By using SOI nanoslot waveguides, suspended Si nanowires, and Si nanofibers, one could achieve a higher sensitivity compared to sensing with a free-space beam (S = 1.0). The sensitivity for gas sensing is higher than that for liquid sensing due to the higher index-contrast. The waveguide sensitivity of an optimized suspended Si nanowire for gas sensing is as high as 1.5, which is much higher than that of a SOI nanoslot waveguide. Furthermore, the optimal design has very large tolerance to the core width variation due to the fabrication error (∆w ~ ±50 nm). In contrast, a Si nanofiber could also give a very high sensitivity (e.g., ~1.43) while the fabrication tolerance is very small (i.e., ∆w < ±5 nm). The comparative study shows that suspended Si nanowire is a good choice to achieve ultra-high waveguide sensitivity.

Capillarics: pre-programmed, self-powered microfluidic circuits built from capillary elements.

PubMed

Safavieh, Roozbeh; Juncker, David

2013-11-07

Microfluidic capillary systems employ surface tension effects to manipulate liquids, and are thus self-powered and self-regulated as liquid handling is structurally and chemically encoded in microscale conduits. However, capillary systems have been limited to perform simple fluidic operations. Here, we introduce complex capillary flow circuits that encode sequential flow of multiple liquids with distinct flow rates and flow reversal. We first introduce two novel microfluidic capillary elements including (i) retention burst valves and (ii) robust low aspect ratio trigger valves. These elements are combined with flow resistors, capillary retention valves, capillary pumps, and open and closed reservoirs to build a capillary circuit that, following sample addition, autonomously delivers a defined sequence of multiple chemicals according to a preprogrammed and predetermined flow rate and time. Such a circuit was used to measure the concentration of C-reactive protein. This work illustrates that as in electronics, complex capillary circuits may be built by combining simple capillary elements. We define such circuits as "capillarics", and introduce symbolic representations. We believe that more complex circuits will become possible by expanding the library of building elements and formulating abstract design rules.

Laser capillary spectrophotometric acquisition of bivariate drop size and concentration data for liquid-liquid dispersion

DOEpatents

Tavlarides, Lawrence L.; Bae, Jae-Heum

1991-01-01

A laser capillary spectrophotometric technique measures real time or near real time bivariate drop size and concentration distribution for a reactive liquid-liquid dispersion system. The dispersion is drawn into a precision-bore glass capillary and an appropriate light source is used to distinguish the aqueous phase from slugs of the organic phase at two points along the capillary whose separation is precisely known. The suction velocity is measured, as is the length of each slug from which the drop free diameter is calculated. For each drop, the absorptivity at a given wavelength is related to the molar concentration of a solute of interest, and the concentration of given drops of the organic phase is derived from pulse heights of the detected light. This technique permits on-line monitoring and control of liquid-liquid dispersion processes.

Vortex Flows in the Liquid Layer and Droplets on a Vibrating Flexible Plate

NASA Astrophysics Data System (ADS)

Aleksandrov, Vladimir; Kopysov, Sergey; Tonkov, Leonid

2018-02-01

In certain conditions, in the layers and droplets of a liquid on a vibrating rectangular flexible plate, vortex flows are formed simultaneously with the excitation of capillary oscillations on the free surface of the liquid layers and droplets. Capillary oscillations in the form of two-dimensional standing waves form Faraday ripples on the free surface of the liquid layer. On the surface of the vibrating droplets, at the excitation of capillary oscillations a light spot reflected from a spotlight source moves along a trajectory in the form of a Lissajous figure observed with a microscope. When vortex flows visualized with graphite microparticles appear in the layer and droplets of a transparent liquid, the trajectory of the light spot on the layer and droplet surface is a two-dimensional trajectory in the form of an ellipse or a saddle. This indicates that the generation of the vortex flows in a liquid at vibrations is due to capillary oscillations in the orthogonally related directions. In the liquid layer and droplets on the surface of the flexible plate, the vibrations of which are generated by bending vibrations, the vortex flows appear due to the plate vibrations and the capillary oscillations of the surface of a layer or a droplet of the liquid. On the free surface of the liquid, the capillary waves, which are parametrically excited by the plate bending vibrations, are additionally modulated by the same bending vibrations in the transverse direction.

Na+-glucose cotransporter is also expressed in mesothelium of species with thick visceral pleura.

PubMed

Sironi, Chiara; Bodega, Francesca; Porta, Cristina; Monaco, Ario; Zocchi, Luciano; Agostoni, Emilio

2008-05-31

Molecular evidence for Na+-glucose cotransporter (SGLT1) in rabbit pleural mesothelium has been recently provided, confirming earlier functional findings on solute-coupled liquid absorption from rabbit pleural space. In this research we checked whether SGLT1 is also expressed in pleural mesothelium of species with thick visceral pleura, which receives blood from systemic circulation, but drains it into pulmonary veins. To this end immunoblot assays were performed on total protein extract of scraped visceral and parietal mesothelium of lambs and adult sheep, and of a human mesothelial cell line. All of them showed SGLT1 specific bands. Moreover, confocal immunofluorescence images of lamb pleural mesothelium showed that SGLT1 is located in apical membrane. Therefore, a solute-coupled liquid absorption should also occur from pleural space of species with thick visceral pleura. Because of this protein-free liquid entering interstitium between visceral mesothelium and capillaries, inherent Starling forces should be different than hitherto considered, and visceral pleura capillaries could absorb liquid even in these species.

Dynamical clustering of red blood cells in capillary vessels.

PubMed

Boryczko, Krzysztof; Dzwinel, Witold; Yuen, David A

2003-02-01

We have modeled the dynamics of a 3-D system consisting of red blood cells (RBCs), plasma and capillary walls using a discrete-particle approach. The blood cells and capillary walls are composed of a mesh of particles interacting with harmonic forces between nearest neighbors. We employ classical mechanics to mimic the elastic properties of RBCs with a biconcave disk composed of a mesh of spring-like particles. The fluid particle method allows for modeling the plasma as a particle ensemble, where each particle represents a collective unit of fluid, which is defined by its mass, moment of inertia, translational and angular momenta. Realistic behavior of blood cells is modeled by considering RBCs and plasma flowing through capillaries of various shapes. Three types of vessels are employed: a pipe with a choking point, a curved vessel and bifurcating capillaries. There is a strong tendency to produce RBC clusters in capillaries. The choking points and other irregularities in geometry influence both the flow and RBC shapes, considerably increasing the clotting effect. We also discuss other clotting factors coming from the physical properties of blood, such as the viscosity of the plasma and the elasticity of the RBCs. Modeling has been carried out with adequate resolution by using 1 to 10 million particles. Discrete particle simulations open a new pathway for modeling the dynamics of complex, viscoelastic fluids at the microscale, where both liquid and solid phases are treated with discrete particles. Figure A snapshot from fluid particle simulation of RBCs flowing along a curved capillary. The red color corresponds to the highest velocity. We can observe aggregation of RBCs at places with the most stagnant plasma flow.

Laser capillary spectrophotometric acquisition of bivariate drop size and concentration data for liquid-liquid dispersion

DOEpatents

Tavlarides, L.L.; Bae, J.H.

1991-12-24

A laser capillary spectrophotometric technique measures real time or near real time bivariate drop size and concentration distribution for a reactive liquid-liquid dispersion system. The dispersion is drawn into a precision-bore glass capillary and an appropriate light source is used to distinguish the aqueous phase from slugs of the organic phase at two points along the capillary whose separation is precisely known. The suction velocity is measured, as is the length of each slug from which the drop free diameter is calculated. For each drop, the absorptivity at a given wavelength is related to the molar concentration of a solute of interest, and the concentration of given drops of the organic phase is derived from pulse heights of the detected light. This technique permits on-line monitoring and control of liquid-liquid dispersion processes. 17 figures.

Dynamics and Stability of Capillary Surfaces: Liquid Switches at Small Scales

NASA Technical Reports Server (NTRS)

Steen, Paul H.; Bhandar, Anand; Vogel, Michael J.; Hirsa, Amir H.

2004-01-01

The dynamics and stability of systems of interfaces is central to a range of technologies related to the Human Exploration and Development of Space (HEDS). Our premise is that dramatic shape changes can be manipulated to advantage with minimal input, if the system is near instability. The primary objective is to develop the science base to allow novel approaches to liquid management in low-gravity based on this premise. HEDS requires efficient, reliable and lightweight technologies. Our poster will highlight our progress toward this goal using the capillary switch as an example. A capillary surface is a liquid/liquid or liquid/gas interface whose shape is determined by surface tension. For typical liquids (e.g., water) against gas on earth, capillary surfaces occur on the millimeterscale and smaller where shape deformation due to gravity is unimportant. In low gravity, they can occur on the centimeter scale. Capillary surfaces can be combined to make a switch a system with multiple stable states. A capillary switch can generate motion or effect force. To be practical, the energy barriers of such a switch must be tunable, its switching time (kinetics) short and its triggering mechanism reliable. We illustrate these features with a capillary switch that consists of two droplets, coupled by common pressure. As long as contact lines remained pinned, motions are inviscid, even at sub-millimeter scales, with consequent promise of low-power consumption at the device level. Predictions of theory are compared to experiment on i) a soap-film prototype at centimeter scale and ii) a liquid droplet switch at millimeter-scale.

A novel facility for 3D micro-irradiation of living cells in a controlled environment by MeV ions.

PubMed

Mäckel, V; Meissl, W; Ikeda, T; Clever, M; Meissl, E; Kobayashi, T; Kojima, T M; Imamoto, N; Ogiwara, K; Yamazaki, Y

2014-01-01

We present a novel facility for micro-irradiation of living targets with ions from a 1.7 MV tandem accelerator. We show results using 1 MeV protons and 2 MeV He(2+). In contrast to common micro-irradiation facilities, which use electromagnetic or electrostatic focusing and specially designed vacuum windows, we employ a tapered glass capillary with a thin end window, made from polystyrene with a thickness of 1-2 μm, for ion focusing and extraction. The capillary is connected to a beamline tilted vertically by 45°, which allows for easy immersion of the extracted ions into liquid environment within a standard cell culture dish. An inverted microscope is used for simultaneously observing the samples as well as the capillary tip, while a stage-top incubator provides an appropriate environment for the samples. Furthermore, our setup allows to target volumes in cells within a μm(3) resolution, while monitoring the target in real time during and after irradiation.

Liquid-crystal-based tunable plasmonic waveguide filters

NASA Astrophysics Data System (ADS)

Yin, Shengtao; Liu, Yan Jun; Xiao, Dong; He, Huilin; Luo, Dan; Jiang, Shouzhen; Dai, Haitao; Ji, Wei; Sun, Xiao Wei

2018-06-01

We propose a liquid-crystal-based tunable plasmonic waveguide filter and numerically investigate its filtering properties. The filter consists of a metal-insulator-metal waveguide with a nanocavity resonator. By filling the nanocavity with birefringent liquid crystals (LCs), we could then vary the effective refractive index of the nanocavity by controlling the alignment of the LC molecules, hence making the filter tunable. The tunable filtering properties are further analyzed in details via the temporal coupled mode theory (CMT) and the finite-difference time-domain (FDTD) method. The simulation results show that the resonant wavelengths have linear redshift as the refractive index of the nanocavity increases and the coupling efficiency is more than 65% without considering the internal loss in the nanocavity and waveguides. These achieved results by the FDTD simulations can be also accurately analyzed by CMT. The compact design of our proposed plasmonic filters is especially favorable for integration, and such filters could find many important potential applications in high-density plasmonic integration circuits.

Determining the imaging plane of a retinal capillary layer in adaptive optical imaging

NASA Astrophysics Data System (ADS)

Yang, Le-Bao; Hu, Li-Fa; Li, Da-Yu; Cao, Zhao-Liang; Mu, Quan-Quan; Ma, Ji; Xuan, Li

2016-09-01

Even in the early stage, endocrine metabolism disease may lead to micro aneurysms in retinal capillaries whose diameters are less than 10 μm. However, the fundus cameras used in clinic diagnosis can only obtain images of vessels larger than 20 μm in diameter. The human retina is a thin and multiple layer tissue, and the layer of capillaries less than 10 μm in diameter only exists in the inner nuclear layer. The layer thickness of capillaries less than 10 μm in diameter is about 40 μm and the distance range to rod&cone cell surface is tens of micrometers, which varies from person to person. Therefore, determining reasonable capillary layer (CL) position in different human eyes is very difficult. In this paper, we propose a method to determine the position of retinal CL based on the rod&cone cell layer. The public positions of CL are recognized with 15 subjects from 40 to 59 years old, and the imaging planes of CL are calculated by the effective focal length of the human eye. High resolution retinal capillary imaging results obtained from 17 subjects with a liquid crystal adaptive optics system (LCAOS) validate our method. All of the subjects’ CLs have public positions from 127 μm to 147 μm from the rod&cone cell layer, which is influenced by the depth of focus. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174274, 11174279, 61205021, 11204299, 61475152, and 61405194).

Mass-controlled capillary viscometer for a Newtonian liquid: Viscosity of water at different temperatures

NASA Astrophysics Data System (ADS)

Digilov, Rafael M.; Reiner, M.

2007-03-01

The operation principle of the mass-controlled capillary viscometer is presented for a Newtonian liquid. The derived equation for the temporal changes of the mass in a liquid column draining under gravity through a discharge capillary tube accounts self-consistently for the inertial convective term associated with the acceleration effect. The viscosity of water measured at different temperatures using the new approach is in good agreement with literature data.

Dynamic Mass Transfer of Hemoglobin at the Aqueous/Ionic-Liquid Interface Monitored with Liquid Core Optical Waveguide.

PubMed

Chen, Xuwei; Yang, Xu; Zeng, Wanying; Wang, Jianhua

2015-08-04

Protein transfer from aqueous medium into ionic liquid is an important approach for the isolation of proteins of interest from complex biological samples. We hereby report a solid-cladding/liquid-core/liquid-cladding sandwich optical waveguide system for the purpose of monitoring the dynamic mass-transfer behaviors of hemoglobin (Hb) at the aqueous/ionic liquid interface. The optical waveguide system is fabricated by using a hydrophobic IL (1,3-dibutylimidazolium hexafluorophosphate, BBimPF6) as the core, and protein solution as one of the cladding layer. UV-vis spectra are recorded with a CCD spectrophotometer via optical fibers. The recorded spectra suggest that the mass transfer of Hb molecules between the aqueous and ionic liquid media involve accumulation of Hb on the aqueous/IL interface followed by dynamic extraction/transfer of Hb into the ionic liquid phase. A part of Hb molecules remain at the interface even after the accomplishment of the extraction/transfer process. Further investigations indicate that the mass transfer of Hb from aqueous medium into the ionic liquid phase is mainly driven by the coordination interaction between heme group of Hb and the cationic moiety of ionic liquid, for example, imidazolium cation in this particular case. In addition, hydrophobic interactions also contribute to the transfer of Hb.

Liquid film drag out in the presence of molecular forces

NASA Astrophysics Data System (ADS)

Schmidhalter, I.; Cerro, R. L.; Giavedoni, M. D.; Saita, F. A.

2013-03-01

From a practical as well as a conceptual point of view, one of the most interesting problems of physicochemical hydrodynamics is the drag out of a liquid film by a moving solid out of a pool of liquid. The basic problem, sometimes denoted the Landau-Levich problem [L. Landau and B. Levich, "Dragging of a liquid by a moving plate," Acta Physicochim. USSR 17, 42-54 (1942)], involves an interesting blend of capillary and viscous forces plus a matching of the static solution for capillary rise with a numerical solution of the film evolution equation, neglecting gravity, on the downstream region of the flow field. The original solution describes experimental data for a wide range of Capillary numbers but fails to match results for large and very small Capillary numbers. Molecular level forces are introduced to create an augmented version of the film evolution equation to show the effect of van der Waals forces at the lower range of Capillary numbers. A closed form solution for static capillary rise, including molecular forces, was matched with a numerical solution of the augmented film evolution equation in the dynamic meniscus region. Molecular forces do not sensibly modify the static capillary rise region, since film thicknesses are larger than the range of influence of van der Waals forces, but are determinant in shaping the downstream dynamic meniscus of the very thin liquid films. As expected, a quantitatively different level of disjoining pressure for different values of molecular constants remains in the very thin liquid film far downstream. Computational results for a wide range of Capillary numbers and Hamaker constants show a clear transition towards a region where the film thickness becomes independent of the coating speed.

Investigation of ferroelectric liquid crystal orientation in the silica microcapillaries

NASA Astrophysics Data System (ADS)

Budaszewski, D.; Domański, A. W.; Woliński, T. R.

2013-05-01

In the paper we present our recent results concerning the orientation of ferroelectric liquid crystal molecules inside silica micro capillaries. We have infiltrated the silica micro capillaries with experimental ferroelectric liquid crystal material W-260K synthesized in the Military University of Technology. The infiltrated micro capillaries were observed under the polarization microscope while both a polarizer and an analyzer were crossed. The studies on the orientation of ferroelectric liquid crystal molecules may contribute to further studies on behavior of this group of liquid crystal materials inside photonic crystal fiber. The obtained results may lead to design of a new type of fast optical fiber sensors.

Capillary test specimen, system, and methods for in-situ visualization of capillary flow and fillet formation

DOEpatents

Hall, Aaron C.; Hosking, F. Michael ,; Reece, Mark

2003-06-24

A capillary test specimen, method, and system for visualizing and quantifying capillary flow of liquids under realistic conditions, including polymer underfilling, injection molding, soldering, brazing, and casting. The capillary test specimen simulates complex joint geometries and has an open cross-section to permit easy visual access from the side. A high-speed, high-magnification camera system records the location and shape of the moving liquid front in real-time, in-situ as it flows out of a source cavity, through an open capillary channel between two surfaces having a controlled capillary gap, and into an open fillet cavity, where it subsequently forms a fillet on free surfaces that have been configured to simulate realistic joint geometries. Electric resistance heating rapidly heats the test specimen, without using a furnace. Image-processing software analyzes the recorded images and calculates the velocity of the moving liquid front, fillet contact angles, and shape of the fillet's meniscus, among other parameters.

Modeling of the anode of a liquid-feed DMFC: Inhomogeneous compression effects and two-phase transport phenomena

NASA Astrophysics Data System (ADS)

García-Salaberri, Pablo A.; Vera, Marcos; Iglesias, Immaculada

2014-01-01

An isothermal two-phase 2D/1D across-the-channel model for the anode of a liquid-feed Direct Methanol Fuel Cell (DMFC) is presented. The model takes into account the effects of the inhomogeneous assembly compression of the Gas Diffusion Layer (GDL), including the spatial variations of porosity, diffusivity, permeability, capillary pressure, and electrical conductivity. The effective anisotropic properties of the GDL are evaluated from empirical data reported in the literature corresponding to Toray carbon paper TGP-H series. Multiphase transport is modeled according to the classical theory of porous media (two-fluid model), considering the effect of non-equilibrium evaporation and condensation of methanol and water. The numerical results evidence that the hydrophobic Leverett J-function approach is physically inconsistent to describe capillary transport in the anode of a DMFC when assembly compression effects are considered. In contrast, more realistic results are obtained when GDL-specific capillary pressure curves reflecting the mixed-wettability characteristics of GDLs are taken into account. The gas coverage factor at the GDL/channel interface also exhibits a strong influence on the gas-void fraction distribution in the GDL, which in turn depends on the relative importance between the capillary resistance induced by the inhomogeneous compression, Rc(∝ ∂pc / ∂ ε) , and the capillary diffusivity, Dbarc(∝ ∂pc / ∂ s) .

Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe

NASA Astrophysics Data System (ADS)

Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H.

2015-12-01

Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp = 200…600 μm, porosity ε = 0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol) = 0 after t = 6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

PubMed

Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

2015-12-01

Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Susceptibility cancellation of a microcoil wound with a paramagnetic-liquid-filled copper capillary

NASA Astrophysics Data System (ADS)

Takeda, Kazuyuki; Takasaki, Tomoya; Takegoshi, K.

2015-09-01

Even though microcoils improve the sensitivity of NMR measurement of tiny samples, magnetic-field inhomogeneity due to the bulk susceptibility effect of the coil material can cause serious resonance-line broadening. Here, we propose to fabricate the microcoil using a thin, hollow copper capillary instead of a wire and fill paramagnetic liquid inside the capillary, so as to cancel the diamagnetic contribution of the copper. Susceptibility cancellation is demonstrated using aqueous solution of NiSO4. In addition, the paramagnetic liquid serves as coolant when it is circulated through the copper capillary, effectively transferring the heat generated by radiofrequency pulses.

Urea functionalized surface-bonded sol-gel coating for on-line hyphenation of capillary microextraction with high-performance liquid chromatography.

PubMed

Jillani, Shehzada Muhammad Sajid; Alhooshani, Khalid

2018-03-30

Sol-gel urea functionalized-[bis(hydroxyethyl)amine] terminated polydimethylsiloxane coating was developed for capillary microextraction-high performance liquid chromatographic analysis from aqueous samples. A fused silica capillary is coated from the inside with surface bonded coating material and is created through in-situ sol-gel reaction. The urea-functionalized coating was immobilized to the inner surface of the capillary by the condensation reaction of silanol groups of capillary and sol-solution. The characterization of the coating material was successfully done by using X-ray photoelectron spectroscopy, thermogravimetric analysis, field emission scanning electron microscope, and energy dispersive X-ray spectrometer. To make a setup of online capillary microextraction-high performance liquid chromatography, the urea functionalized capillary was installed in the HPLC manual injection port. The analytes of interest were pre-concentrated in the coated sampling loop, desorbed by the mobile phase, chromatographically separated on C-18 column, and analyzed by UV detector. Sol-gel coated capillaries were used for online extraction and high-performance liquid chromatographic analysis of phenols, ketones, aldehydes, and polyaromatic hydrocarbons. This newly developed coating showed excellent extraction for a variety of analytes ranging from highly polar to non-polar in nature. The analysis using sol-gel coating showed excellent overall sensitivity in terms of lower detection limits (S/N = 3) for the analytes (0.10 ng mL -1 -14.29 ng mL -1 ) with acceptable reproducibility that is less than 12.0%RSD (n = 3). Moreover, the capillary to capillary reproducibility of the analysis was also tested by changing the capillary of the same size. This provided excellent%RSD of less than 10.0% (n = 3). Copyright © 2018 Elsevier B.V. All rights reserved.

Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides

PubMed Central

Chandrahalim, Hengky; Rand, Stephen C.; Fan, Xudong

2016-01-01

We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator – waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3′-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena. PMID:27600872

Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides.

PubMed

Chandrahalim, Hengky; Rand, Stephen C; Fan, Xudong

2016-09-07

We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator - waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3'-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena.

InGaAsP/InP optical waveguide switch operated by a carrier-induced change in the refractive index

NASA Astrophysics Data System (ADS)

Mikami, O.; Nakagome, H.

1985-11-01

Waveguided semiconductor optical switches operated by a carrier-induced change in the refractive-index associated with the plasma dispersion are proposed. InGaAsP/InP four-port switches having two intersecting single-mode channel waveguides are fabricated by selective liquid-phase epitaxy and investigated at 1.5 microns wavelength. Optical switching is observed as a result of mode interference in the waveguide intersection region.

Microfluidic immunosensor with integrated liquid core waveguides for sensitive Mie scattering detection of avian influenza antigens in a real biological matrix.

PubMed

Heinze, Brian C; Gamboa, Jessica R; Kim, Keesung; Song, Jae-Young; Yoon, Jeong-Yeol

2010-11-01

This work presents the use of integrated, liquid core, optical waveguides for measuring immunoagglutination-induced light scattering in a microfluidic device, towards rapid and sensitive detection of avian influenza (AI) viral antigens in a real biological matrix (chicken feces). Mie scattering simulations were performed and tested to optimize the scattering efficiency of the device through proper scatter angle waveguide geometry. The detection limit is demonstrated to be 1 pg mL(-1) in both clean buffer and real biological matrix. This low detection limit is made possible through on-chip diffusional mixing of AI target antigens and high acid content microparticle assay reagents, coupled with real-time monitoring of immunoagglutination-induced forward Mie scattering via high refractive index liquid core optical waveguides in close proximity (100 μm) to the sample chamber. The detection time for the assay is <2 min. This device could easily be modified to detect trace levels of any biological molecules that antibodies are available for, moving towards a robust platform for point-of-care disease diagnostics.

Rotor for processing liquids using movable capillary tubes

DOEpatents

Johnson, Wayne F.; Burtis, Carl A.; Walker, William A.

1989-01-01

A rotor assembly for processing liquids, especially whole blood samples, is disclosed. The assembly includes apparatus for separating non-liquid components of whole blood samples from liquid components, apparatus for diluting the separated liquid component with a diluent and apparatus for transferring the diluted sample to an external apparatus for analysis. The rotor assembly employs several movable capillary tubes to handle the sample and diluents. A method for using the rotor assembly to process liquids is also described.

Rotor for processing liquids using movable capillary tubes

DOEpatents

Johnson, Wayne F [Loudon, TN; Burtis, Carl A [Oak Ridge, TN; Walker, William A [Knoxville, TN

1989-05-30

A rotor assembly for processing liquids, especially whole blood samples, is disclosed. The assembly includes apparatus for separating non-liquid components of whole blood samples from liquid components, apparatus for diluting the separated liquid component with a diluent and apparatus for transferring the diluted sample to an external apparatus for analysis. The rotor assembly employs several movable capillary tubes to handle the sample and diluents. A method for using the rotor assembly to process liquids is also described.

The waveguide laser - A review

NASA Technical Reports Server (NTRS)

Degnan, J. J.

1976-01-01

The present article reviews the fundamental physical principles essential to an understanding of waveguide gas and liquid lasers, and the current technological state of these devices. At the present time, waveguide laser transitions span the visible through submillimeter regions of the wavelength spectrum. The introduction discusses the many applications of waveguide lasers and the wide variety of laser configurations that are possible. Section 1 summarizes the properties of modes in hollow dielectric waveguides of circular, rectangular, and planar cross section. Section 2 considers various approaches to optical feedback including internal and external mirror Fabry-Perot type resonators, hollow waveguide distributed feedback structures, and ring-resonant configurations. Section 3 discusses those aspects of molecular kinetic and laser theory pertinent to the design and optimization of waveguide gas lasers.

Novel materials as potential infrared laser hosts

NASA Astrophysics Data System (ADS)

Sarkies, Julian Richard

The work presented in this thesis has concentrated on an assessment and characterisation of potential laser host media which will only support low phonon or vibrational modes. This is a necessary criterion if systems in which the active ions are lanthanides are to be made to lase in the mid-infrared, as in conventional host media non- radiative processes dominate transitions in this region. Research has concentrated upon two main areas. Firstly a spectroscopic study of lanthanide doped PBr3/AlBr3/SbBr3 was undertaken. A detailed investigation and characterisation of the stable solution formation region was carried out. The doping levels achievable were seen to vary across the lanthanide series from a maximum 0.24mol% for praesodymium to a minimum 0.15mol% for ytterbium. Energies of the characteristic 4 f absorptions of the trivalent lanthanides were measured, along with their oscillator strengths. Judd-Ofelt parameters were found for several rare earths. Stimulated emission cross sections were found to be higher than in conventional glass hosts for certain transitions, such as 6.83 × 10 -20 cm2 for the 4F3/2 --> 4I11/2 transition in the Nd3+ doped liquid. This was verified both experimentally and by the Ladenburg-Fuchtbauer relation when compared to a standard silicate glass. The behaviour, both spectroscopic and physical, of the doped solutions was seen to change dramatically upon heating. Heating the solutions gave rise to higher crystallisation rates, but lower non-radiative relaxation rates. Waveguide and laser experiments were attempted in both bulk and capillary geometries, however material factors such as crystallisation and thermal lensing prevented laser action. Secondly, rare earth doped planar waveguides of zinc sulphide were prepared. A full characterisation of the way in which waveguide loss was affected by factors such as deposition rate, doping level and waveguide masking during evaporation was performed. Waveguide losses as low as 1.5dB/cm at 980nm were measured. The loss was seen to have a strong λ-4 dependence, indicating it was predominantly due to Rayleigh scattering. Deposition onto heated substrates and post deposition annealing increased the loss significantly. Shielding the substrate from the radiant heating of the evaporation boat by partial masking of the substrate reduced the loss significantly. Doping the films caused a large increase in the loss for dopant concentrations of above 0.8mol%. Emission was observed from both Er3+ and Nd 3+ doped waveguides, and fluorescent lifetimes measured. The emission cross sections were measured for the 4F3/2 --> 4I11/2 transition in the Nd3+ doped waveguide, and for the 4I13/2 --> 4I 15/2 transition in the Er3+ doped waveguide. Multilayer dielectric mirrors were deposited onto the ends of a Nd3+ doped waveguide, forming a fully integrated resonator. The low damage threshold of the multilayer coatings precluded laser action. These results are believed to be the first ever reported for thermally evaporated doped zinc sulphide waveguides. This system has shown considerable promise as an infrared laser host, the future implications of this work are discussed and possible directions for future research suggested.

Rotor for processing liquids using movable capillary tubes

DOEpatents

Johnson, W.F.; Burtis, C.A.; Walker, W.A.

1987-07-17

A rotor assembly for processing liquids, especially whole blood samples, is disclosed. The assembly includes apparatus for separating non-liquid components of whole blood samples from liquid components, apparatus for diluting the separated liquid component with a diluent and apparatus for transferring the diluted sample to an external apparatus for analysis. The rotor assembly employs several movable capillary tubes to handle the sample and diluents. A method for using the rotor assembly to process liquids is also described. 5 figs.

Triggering vacuum capillaries for pneumatic pumping and metering liquids in point-of-care immunoassays.

PubMed

Weng, Kuo-Yao; Chou, Nien-Jen; Cheng, Jya-Wei

2008-07-01

An innovative vacuum capillary pneumatic actuation concept that can be used for point-of-care testing has been investigated. The vacuum glass capillaries are encapsulated within a laminated pouch and incorporated into the fluidic card. Vacuum glass capillaries broken by external force such as finger pressure, generate the pneumatic forces to induce liquid flow in the fluidic system. The sizes of vacuum capillary play a vital role in the pumping and metering functions of the system. The luteinizing hormone (LH) chromatographic immunoassay performances in the fluidic cards show consistency comparable to that obtained by manual micropipetting. The vacuum capillary pneumatic actuation will be applied in other complex handling step bioassays and lab-on-a-chip devices.

Surface transport and stable trapping of particles and cells by an optical waveguide loop.

PubMed

Hellesø, Olav Gaute; Løvhaugen, Pål; Subramanian, Ananth Z; Wilkinson, James S; Ahluwalia, Balpreet Singh

2012-09-21

Waveguide trapping has emerged as a useful technique for parallel and planar transport of particles and biological cells and can be integrated with lab-on-a-chip applications. However, particles trapped on waveguides are continuously propelled forward along the surface of the waveguide. This limits the practical usability of the waveguide trapping technique with other functions (e.g. analysis, imaging) that require particles to be stationary during diagnosis. In this paper, an optical waveguide loop with an intentional gap at the centre is proposed to hold propelled particles and cells. The waveguide acts as a conveyor belt to transport and deliver the particles/cells towards the gap. At the gap, the diverging light fields hold the particles at a fixed position. The proposed waveguide design is numerically studied and experimentally implemented. The optical forces on the particle at the gap are calculated using the finite element method. Experimentally, the method is used to transport and trap micro-particles and red blood cells at the gap with varying separations. The waveguides are only 180 nm thick and thus could be integrated with other functions on the chip, e.g. microfluidics or optical detection, to make an on-chip system for single cell analysis and to study the interaction between cells.

Ionic liquid-modified materials for solid-phase extraction and separation: a review.

PubMed

Vidal, Lorena; Riekkola, Marja-Liisa; Canals, Antonio

2012-02-17

In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently joined the studies. Although imidazolium is still clearly the most commonly used ionic liquid for the covalently modification of materials, the exploitation of pyridinium and phosphonium will most probably increase in the future. Copyright © 2011 Elsevier B.V. All rights reserved.

Large scale simulation of liquid water transport in a gas diffusion layer of polymer electrolyte membrane fuel cells using the lattice Boltzmann method

NASA Astrophysics Data System (ADS)

Sakaida, Satoshi; Tabe, Yutaka; Chikahisa, Takemi

2017-09-01

A method for the large-scale simulation with the lattice Boltzmann method (LBM) is proposed for liquid water movement in a gas diffusion layer (GDL) of polymer electrolyte membrane fuel cells. The LBM is able to analyze two-phase flows in complex structures, however the simulation domain is limited due to heavy computational loads. This study investigates a variety means to reduce computational loads and increase the simulation areas. One is applying an LBM treating two-phases as having the same density, together with keeping numerical stability with large time steps. The applicability of this approach is confirmed by comparing the results with rigorous simulations using actual density. The second is establishing the maximum limit of the Capillary number that maintains flow patterns similar to the precise simulation; this is attempted as the computational load is inversely proportional to the Capillary number. The results show that the Capillary number can be increased to 3.0 × 10-3, where the actual operation corresponds to Ca = 10-5∼10-8. The limit is also investigated experimentally using an enlarged scale model satisfying similarity conditions for the flow. Finally, a demonstration is made of the effects of pore uniformity in GDL as an example of a large-scale simulation covering a channel.

Inverse procedure for simultaneous evaluation of viscosity and density of Newtonian liquids from dispersion curves of Love waves

NASA Astrophysics Data System (ADS)

Kiełczyński, P.; Szalewski, M.; Balcerzak, A.

2014-07-01

Simultaneous determination of the viscosity and density of liquids is of great importance in the monitoring of technological processes in the chemical, petroleum, and pharmaceutical industry, as well as in geophysics. In this paper, the authors present the application of Love waves for simultaneous inverse determination of the viscosity and density of liquids. The inversion procedure is based on measurements of the dispersion curves of phase velocity and attenuation of ultrasonic Love waves. The direct problem of the Love wave propagation in a layered waveguide covered by a viscous liquid was formulated and solved. Love waves propagate in an elastic layered waveguide covered on its surface with a viscous (Newtonian) liquid. The inverse problem is formulated as an optimization problem with appropriately constructed objective function that depends on the material properties of an elastic waveguide of the Love wave, material parameters of a liquid (i.e., viscosity and density), and the experimental data. The results of numerical calculations show that Love waves can be efficiently applied to determine simultaneously the physical properties of liquids (i.e., viscosity and density). Sensors based on this method can be very attractive for industrial applications to monitor on-line the parameters (density and viscosity) of process liquid during the course of technological processes, e.g., in polymer industry.

The use of hollow-core photonic crystal fibres as biological sensors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malinin, A V; Skibina, Yu S; Tuchin, Valerii V

2011-04-30

The results of development and study of a new type of a hollow-core photonic crystal fibre with radially increasing diameter of capillaries in the structured cladding are presented. The waveguide possesses a specific transmission spectrum and can be used as an efficient analyser of biological media. (optical technologies in biophysics and medicine)

Electrokinetic micro-fluid mixer

DOEpatents

Paul, Phillip H.; Rakestraw, David J.

2000-01-01

A method and apparatus for efficiently and rapidly mixing liquids in a system operating in the creeping flow regime such as would be encountered in capillary-based systems. By applying an electric field to each liquid, the present invention is capable of mixing together fluid streams in capillary-based systems, where mechanical or turbulent stirring cannot be used, to produce a homogeneous liquid.

A low-threshold, high-efficiency microfluidic waveguide laser.

PubMed

Vezenov, Dmitri V; Mayers, Brian T; Conroy, Richard S; Whitesides, George M; Snee, Preston T; Chan, Yinthai; Nocera, Daniel G; Bawendi, Moungi G

2005-06-29

This communication describes a long (1 cm), laser-pumped, liquid core-liquid cladding (L2) waveguide laser. This device provides a simple, high intensity, tunable light source for microfludic applications. Using a core solution of 2 mM rhodamine 640 perchlorate, optically pumped by a frequency-doubled Nd:YAG laser, we found that the threshold for lasing was as low as 22 muJ (16-ns pulse length) and had a slope efficiency up to 20%. The output wavelength was tunable over a 20-nm range by changing the ratio of solvent components (dimethyl sulfoxide and methanol) in the liquid core.

Growth of metal-organic framework HKUST-1 in capillary using liquid-phase epitaxy for open-tubular capillary electrochromatography and capillary liquid chromatography.

PubMed

Bao, Tao; Zhang, Juan; Zhang, Wenpeng; Chen, Zilin

2015-02-13

Much attention is being paid to applying metal-organic frameworks (MOFs) as stationary phases in chromatography because of their fascinating properties, such as large surface-to-volume ratios, high levels of porosity, and selective adsorption. HKUST-1 is one of the best-studied face-centered-cubic MOF containing nano-sized channels and side pockets for film growth. However, growth of HKUST-1 framework inside capillary column as stationary phase for capillary electrochromatography is a challenge work. In this work, we carry out the growth of HKUST-1 on the inner wall of capillary by using liquid-phase epitaxy process at room temperature. The fabricated HKUST-1@capillary can be successfully used for the separation of substituted benzene including methylbenzene, ethylbenzene, styrene, chlorobenzene, bromobenzene, o-dichlorobenzene, benzene series, phenolic acids, and benzoic acids derivates. High column efficiency of 1.5×10(5) N/m for methylbenzene was achieved. The formation of HKUST-1 grown in the capillary was confirmed and characterized by scanning electron microscopy images, Fourier transform infrared spectra and X-ray diffraction. The column showed long lifetime and excellent stability. The relative standard deviations for intra-day and inter-day repeatability of the HKUST-1@capillary were lower than 7%. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of capillary heterogeneity on vapor-liquid counterflow in porous media

NASA Astrophysics Data System (ADS)

Stubos, A. K.; Satik, C.; Yortsos, Y. C.

1992-06-01

Based on a continuum description, the effect of capillary heterogeneity, induced by variation in permeability, on the steady state, countercurrent, vapor-liquid flow in porous media is analyzed. It is shown that the heterogeneity acts as a body force that may enhance or diminish gravity effects on heat pipes. Selection rules that determine the steady states reached in homogeneous, gravity-driven heat pipes are also formulated. It is shown that the 'infinite' two-phase zone may terminate by a substantial change in the permeability somewhere in the medium. The two possible sequences, liquid-liquid dominated-dry, or liquid-vapor dominated-dry find applications in geothermal systems. Finally, it is shown that although weak heterogeneity affects only gravity controlled flows, stronger variations in permeability can give rise to significant capillary effects.

A design tool for predicting the capillary transport characteristics of fuel cell diffusion media using an artificial neural network

NASA Astrophysics Data System (ADS)

Kumbur, E. C.; Sharp, K. V.; Mench, M. M.

Developing a robust, intelligent design tool for multivariate optimization of multi-phase transport in fuel cell diffusion media (DM) is of utmost importance to develop advanced DM materials. This study explores the development of a DM design algorithm based on artificial neural network (ANN) that can be used as a powerful tool for predicting the capillary transport characteristics of fuel cell DM. Direct measurements of drainage capillary pressure-saturation curves of the differently engineered DMs (5, 10 and 20 wt.% PTFE) were performed at room temperature under three compressions (0, 0.6 and 1.4 MPa) [E.C. Kumbur, K.V. Sharp, M.M. Mench, J. Electrochem. Soc. 154(12) (2007) B1295-B1304; E.C. Kumbur, K.V. Sharp, M.M. Mench, J. Electrochem. Soc. 154(12) (2007) B1305-B1314; E.C. Kumbur, K.V. Sharp, M.M. Mench, J. Electrochem. Soc. 154(12) (2007) B1315-B1324]. The generated benchmark data were utilized to systematically train a three-layered ANN framework that processes the feed-forward error back propagation methodology. The designed ANN successfully predicts the measured capillary pressures within an average uncertainty of ±5.1% of the measured data, confirming that the present ANN model can be used as a design tool within the range of tested parameters. The ANN simulations reveal that tailoring the DM with high PTFE loading and applying high compression pressure lead to a higher capillary pressure, therefore promoting the liquid water transport within the pores of the DM. Any increase in hydrophobicity of the DM is found to amplify the compression effect, thus yielding a higher capillary pressure for the same saturation level and compression.

Effect of dispersion forces on the capillary-wave fluctuations of liquid surfaces.

PubMed

Chacón, Enrique; Fernández, Eva M; Tarazona, Pedro

2014-04-01

We present molecular dynamics evidence for the nonanalytic effects of the long-range dispersion forces on the capillary waves fluctuations of a Lennard-Jones liquid surface. The results of the intrinsic sampling method, for the analysis of the instantaneous interfacial shape, are obtained in large systems for several cut-off distances of the potential tail, and they show good agreement with the theoretical prediction by Napiórkowski and Dietrich, based on a density functional analysis. The enhancement of the capillary waves is quantified to be within 1% for a simple liquid near its triple point.

Measurements and simulation of liquid films during drainage displacements and snap-off in constricted capillary tubes.

PubMed

Roman, Sophie; Abu-Al-Saud, Moataz O; Tokunaga, Tetsu; Wan, Jiamin; Kovscek, Anthony R; Tchelepi, Hamdi A

2017-12-01

When a wetting liquid is displaced by air in a capillary tube, a wetting film develops between the tube wall and the air that is responsible for the snap-off mechanism of the gas phase. By dissolving a dye in the wetting phase it is possible to relate a measure of the absorbance in the capillary to the thickness of liquid films. These data could be used to compare with cutting edge numerical simulations of the dynamics of snap-off for which experimental and numerical data are lacking. Drainage experiments in constricted capillary tubes were performed where a dyed wetting liquid is displaced by air for varying flow rates. We developed an optical method to measure liquid film thicknesses that range from 3 to 1000μm. The optical measures are validated by comparison with both theory and direct numerical simulations. In a constricted capillary tube we observed, both experimentally and numerically, a phenomenon of snap-off coalescence events in the vicinity of the constriction that bring new insights into our understanding and modeling of two-phase flows. In addition, the good agreement between experiments and numerical simulations gives confidence to use the numerical method for more complex geometries in the future. Copyright © 2017 Elsevier Inc. All rights reserved.

A theoretical examination of the performances of wavelength multiplexers utilizing planar optical waveguides

NASA Astrophysics Data System (ADS)

Gomaa, M. L.; Chartier, G.

1985-04-01

The performances of distributed coupling wavelength multiplexer-demultiplexer devices for optical telecommunications applications, i.e., data transfer, are assessed theoretically. The values used for the refraction indices and waveguide dimensions are based on the ionic exchange between the glass layer and a base salt bath. Gradients in the indices are also considered. A shift of indices is assumed to be present between parallel waveguides of different thicknesses separated by a liquid bath. The behavior of the two waveguides is then the variations of the coupling and energy exchanged as functions of the wavelength transmitted. Attention is also given to the case of identical coupled waveguides.

Mathematical and computational studies of equilibrium capillary free surfaces

NASA Technical Reports Server (NTRS)

Albright, N.; Chen, N. F.; Concus, P.; Finn, R.

1977-01-01

The results of several independent studies are presented. The general question is considered of whether a wetting liquid always rises higher in a small capillary tube than in a larger one, when both are dipped vertically into an infinite reservoir. An analytical investigation is initiated to determine the qualitative behavior of the family of solutions of the equilibrium capillary free-surface equation that correspond to rotationally symmetric pendent liquid drops and the relationship of these solutions to the singular solution, which corresponds to an infinite spike of liquid extending downward to infinity. The block successive overrelaxation-Newton method and the generalized conjugate gradient method are investigated for solving the capillary equation on a uniform square mesh in a square domain, including the case for which the solution is unbounded at the corners. Capillary surfaces are calculated on the ellipse, on a circle with reentrant notches, and on other irregularly shaped domains using JASON, a general purpose program for solving nonlinear elliptic equations on a nonuniform quadrilaterial mesh. Analytical estimates for the nonexistence of solutions of the equilibrium capillary free-surface equation on the ellipse in zero gravity are evaluated.

A field-deployable compound-specific isotope analyzer based on quantum cascade laser and hollow waveguide

NASA Astrophysics Data System (ADS)

Wu, Sheng; Deev, Andrei

2013-01-01

A field deployable Compound Specific Isotope Analyzer (CSIA) coupled with capillary chromatogrpahy based on Quantum Cascade (QC) lasers and Hollow Waveguide (HWG) with precision and chemical resolution matching mature Mass Spectroscopy has been achieved in our laboratory. The system could realize 0.3 per mil accuracy for 12C/13C for a Gas Chromatography (GC) peak lasting as short as 5 seconds with carbon molar concentration in the GC peak less than 0.5%. Spectroscopic advantages of HWG when working with QC lasers, i.e. single mode transmission, noiseless measurement and small sample volume, are compared with traditional free space and multipass spectroscopy methods.

Simulating human photoreceptor optics using a liquid-filled photonic crystal fiber.

PubMed

Rativa, Diego; Vohnsen, Brian

2011-02-11

We introduce a liquid-filled photonic crystal fiber to simulate a retinal cone photoreceptor mosaic and the directionality selective mechanism broadly known as the Stiles-Crawford effect. Experimental measurements are realized across the visible spectrum to study waveguide coupling and directionality at different managed waveguide parameters. The crystal fiber method is a hybrid tool between theory and a real biological sample and a valuable addition as a retina model for real eye simulations.

Voltage- and temperature- controlled LC:PDMS waveguide channels

NASA Astrophysics Data System (ADS)

Rutkowska, Katarzyna A.; Asquini, Rita; d'Alessandro, Antonio

2017-08-01

In this paper, we present our studies on electrical and thermal tuning of light propagation in waveguide channels, made for the scope from a polydimethylsiloxane (PDMS) substrate infiltrated with nematic liquid crystal (LC). We demonstrated, via numerical simulations, the changes of the waveguide optical parameters when solicited by temperature changes or electric fields. Moreover, the paper goes through the fabrication process of a waveguide channel sample and its characterization, as well as some preliminary experimental trials of sputtering indium tin oxide (ITO) and chromium layers on PDMS substrate to obtain flat electrodes.

Determining CDOM Absorption Spectra in Diverse Coastal Environments Using a Multiple Pathlength, Liquid Core Waveguide System. Measuring the Absorption of CDOM in the Field Using a Multiple Pathlength Liquid Waveguide System

NASA Technical Reports Server (NTRS)

Miller, Richard L.; Belz, Mathias; DelCastillo, Carlos; Trzaska, Rick

2000-01-01

We evaluated the accuracy, sensitivity and precision of a multiple pathlength, liquid core waveguide (MPLCW) system for measuring colored dissolved organic matter (CDOM) absorption in the UV-visible spectral range (370-700 nm). The MPLCW has four optical paths (2.0, 9.8, 49.3, and 204 cm) coupled to a single Teflon AF sample cell. Water samples were obtained from inland, coastal and ocean waters ranging in salinity from 0 to 36 PSU. Reference solutions for the MPLCW were made having a refractive index of the sample. CDOM absorption coefficients, a(sub CDOM), and the slope of the log-linearized absorption spectra, S, were compared with values obtained using a dual-beam spectrophotometer. Absorption of phenol red secondary standards measured by the MPLCW at 558 nm were highly correlated with spectrophotometer values (r > 0.99) and showed a linear response across all four pathlengths. Values of a(sub CDOM) measured using the MPLCW were virtually identical to spectrophotometer values over a wide range of concentrations. The dynamic range of a(sub CDOM) for MPLCW measurements was 0.002 - 231.5/m. At low CDOM concentrations (a(sub 370) < 0.1/m) spectrophotometric a(sub CDOM) were slightly greater than MPLCW values and showed larger fluctuations at longer wavelengths due to limitations in instrument precision. In contrast, MPLCW spectra followed an exponential to 600 nm for all samples. The maximum deviation in replicate MPLCW spectra was less than 0.001 absorbance units. The portability, sampling, and optical characteristics of a MPLCW system provide significant enhancements for routine CDOM absorption measurements in a broad range of natural waters.

Spectroscopic chemical analysis methods and apparatus

NASA Technical Reports Server (NTRS)

Hug, William F. (Inventor); Reid, Ray D. (Inventor)

2009-01-01

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted simultaneously with native fluorescence spectroscopy to provide high levels of sensitivity and specificity in the same instrument.

Spectroscopic chemical analysis methods and apparatus

NASA Technical Reports Server (NTRS)

Reid, Ray D. (Inventor); Hug, William F. (Inventor)

2010-01-01

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted simultaneously with native fluorescence spectroscopy to provide high levels of sensitivity and specificity in the same instrument.

Optical trapping and propulsion of red blood cells on waveguide surfaces.

PubMed

Ahluwalia, Balpreet Singh; McCourt, Peter; Huser, Thomas; Hellesø, Olav Gaute

2010-09-27

We have studied optical trapping and propulsion of red blood cells in the evanescent field of optical waveguides. Cell propulsion is found to be highly dependent on the biological medium and serum proteins the cells are submerged in. Waveguides made of tantalum pentoxide are shown to be efficient for cell propulsion. An optical propulsion velocity of up to 
6 µm/s on a waveguide with a width of ~6 µm is reported. Stable optical trapping and propulsion of cells during transverse flow is also reported.

Drop Tower Experiments concerning Fluid Management under Microgravity

NASA Astrophysics Data System (ADS)

Gaulke, Diana; Dreyer, Michael

2012-07-01

Transport and positioning of liquid under microgravity is done utilizing capillary forces. Therefore, capillary transport processes have to be understood for a wide variety of space applications, ranging from propellant management in tanks of space transportation systems to eating and drinking devices for astronauts. There are two types of liquid transportation in microgravity using capillary forces. First, the driven liquid flow in open channels where the capillary forces at free surfaces ensure a gas and vapor free flow. Here it is important to know the limiting flow rate through such an open channel before the free surface collapses and gas is sucked into the channel. A number of different experiments at the drop tower Bremen, on sounding rockets and at the ISS have been conducted to analyse this phenomenon within different geometries. As result a geometry dependent theory for calculating the maximum flow rate has been found. On the other hand liquid positioning and transportation requires the capillary pressure of curved surfaces to achieve a liquid flow to a desired area. Especially for space applications the weight of structure has to be taken into account for development. For example liquid positioning in tanks can be achieved via a complicated set of structure filling the whole tank resulting in heavy devices not reasonable in space applications. Astrium developed in cooperation with ZARM a propellant management device much smaller than the tank volume and ensuring a gas and vapour free supply of propellant to the propulsion system. In the drop tower Bremen a model of this device was tested concerning different microgravity scenarios. To further decrease weight and ensure functionality within different scenarios structure elements are designed as perforated geometries. Capillary transport between perforated plates has been analyzed concerning the influence of geometrical pattern of perforations. The conducted experiments at the drop tower Bremen show the remarkable influence of perforations on the capillary transport capability.

Live Imaging of the Lung

PubMed Central

Looney, Mark R.; Bhattacharya, Jahar

2015-01-01

Live lung imaging has spanned the discovery of capillaries in the frog lung by Malpighi to the current use of single and multiphoton imaging of intravital and isolated perfused lung preparations incorporating fluorescent molecular probes and transgenic reporter mice. Along the way, much has been learned about the unique microcirculation of the lung, including immune cell migration and the mechanisms by which cells at the alveolar-capillary interface communicate with each other. In this review, we highlight live lung imaging techniques as applied to the role of mitochondria in lung immunity, mechanisms of signal transduction in lung compartments, studies on the composition of alveolar wall liquid, and neutrophil and platelet trafficking in the lung under homeostatic and inflammatory conditions. New applications of live lung imaging and the limitations of current techniques are discussed. PMID:24245941

Sheathless interface for coupling capillary electrophoresis with mass spectrometry

DOEpatents

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.

Novel integrated microdialysis-amperometric system for in vitro detection of dopamine secreted from PC12 cells: design, construction, and validation.

PubMed

Migheli, Rossana; Puggioni, Giulia; Dedola, Sonia; Rocchitta, Gaia; Calia, Giammario; Bazzu, Gianfranco; Esposito, Giovanni; Lowry, John P; O'Neill, Robert D; Desole, M S; Miele, Egidio; Serra, Pier A

2008-09-15

A novel dual channel in vitro apparatus, derived from a previously described design, has been coupled with dopamine (DA) microsensors for the flow-through detection of DA secreted from PC12 cells. The device, including two independent microdialysis capillaries, was loaded with a solution containing PC12 cells while a constant phosphate-buffered saline (PBS) medium perfusion was carried out using a dual channel miniaturized peristaltic pump. One capillary was perfused with normal PBS, whereas extracellular calcium was removed from extracellular fluid of the second capillary. After a first period of stabilization and DA baseline recording, KCl (75 mM) was added to the perfusion fluid of both capillaries. In this manner, a simultaneous "treatment-control" experimental design was performed to detect K+-evoked calcium-dependent DA secretion. For this purpose, self-referencing DA microsensors were developed, and procedures for making, testing, and calibrating them are described in detail. The electronic circuitry was derived from previously published schematics and optimized for dual sensor constant potential amperometry applications. The microdialysis system was tested and validated in vitro under different experimental conditions, and DA secretion was confirmed by high-performance liquid chromatography with electrochemical detection (HPLC-EC). PC12 cell viability was quantified before and after each experiment. The proposed apparatus serves as a reliable model for studying the effects of different drugs on DA secretion through the direct comparison of extracellular DA increase in treatment-control experiments performed on the same initial PC12 cell population.

High-throughput biological small-angle X-ray scattering with a robotically loaded capillary cell

PubMed Central

Nielsen, S. S.; Møller, M.; Gillilan, R. E.

2012-01-01

With the rise in popularity of biological small-angle X-ray scattering (BioSAXS) measurements, synchrotron beamlines are confronted with an ever-increasing number of samples from a wide range of solution conditions. To meet these demands, an increasing number of beamlines worldwide have begun to provide automated liquid-handling systems for sample loading. This article presents an automated sample-loading system for BioSAXS beamlines, which combines single-channel disposable-tip pipetting with a vacuum-enclosed temperature-controlled capillary flow cell. The design incorporates an easily changeable capillary to reduce the incidence of X-ray window fouling and cross contamination. Both the robot-control and the data-processing systems are written in Python. The data-processing code, RAW, has been enhanced with several new features to form a user-friendly BioSAXS pipeline for the robot. The flow cell also supports efficient manual loading and sample recovery. An effective rinse protocol for the sample cell is developed and tested. Fluid dynamics within the sample capillary reveals a vortex ring pattern of circulation that redistributes radiation-damaged material. Radiation damage is most severe in the boundary layer near the capillary surface. At typical flow speeds, capillaries below 2 mm in diameter are beginning to enter the Stokes (creeping flow) regime in which mixing due to oscillation is limited. Analysis within this regime shows that single-pass exposure and multiple-pass exposure of a sample plug are functionally the same with regard to exposed volume when plug motion reversal is slow. The robot was tested on three different beamlines at the Cornell High-Energy Synchrotron Source, with a variety of detectors and beam characteristics, and it has been used successfully in several published studies as well as in two introductory short courses on basic BioSAXS methods. PMID:22509071

Condensation in Nanoporous Packed Beds.

PubMed

Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

2016-05-10

In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

On-demand control of microfluidic flow via capillary-tuned solenoid microvalve suction.

PubMed

Zhang, Qiang; Zhang, Peiran; Su, Yetian; Mou, Chunbo; Zhou, Teng; Yang, Menglong; Xu, Jian; Ma, Bo

2014-12-21

A simple, low-cost and on-demand microfluidic flow controlling platform was developed based on a unique capillary-tuned solenoid microvalve suction effect without any outer pressure source. The suction effect was innovatively employed as a stable and controllable driving force for the manipulation of the microfluidic system by connecting a piece of capillary between the microvalve and the microfluidic chip, which caused significant hydrodynamic resistance differences among the solenoid valve ports and changed the flowing mode inside the valve. The volume of sucked liquid could be controlled from microliters even down to picoliters either by decreasing the valve energized duration (from a maximum energized duration to the valve response time of 20 ms) or by increasing the inserted capillary length (i.e., its hydrodynamic resistance). Several important microfluidic unit operations such as cell/droplet sorting and on-demand size-controllable droplet generation have been demonstrated on the developed platform and both simulations and experiments confirmed that this platform has good controllability and stability.

Capillary Absorption Spectrometer for 13C Isotopic Composition of Pico to Subpico Molar Sample Quantities

NASA Astrophysics Data System (ADS)

Moran, J.; Kelly, J.; Sams, R.; Newburn, M.; Kreuzer, H.; Alexander, M.

2011-12-01

Quick incorporation of IR spectroscopy based isotope measurements into cutting edge research in biogeochemical cycling attests to the advantages of a spectroscopy versus mass spectrometry method for making some 13C measurements. The simple principles of optical spectroscopy allow field portability and provide a more robust general platform for isotope measurements. We present results with a new capillary absorption spectrometer (CAS) with the capability of reducing the sample size required for high precision isotopic measurements to the picomolar level and potentially the sub-picomolar level. This work was motivated by the minute sample size requirements for laser ablation isotopic studies of carbon cycling in microbial communities but has potential to be a valuable tool in other areas of biological and geological research. The CAS instrument utilizes a capillary waveguide as a sample chamber for interrogating CO2 via near IR laser absorption spectroscopy. The capillary's small volume (~ 0.5 mL) combined with propagation and interaction of the laser mode with the entire sample reduces sample size requirements to a fraction of that accessible with commercially available IR absorption including those with multi-pass or ring-down cavity systems. Using a continuous quantum cascade laser system to probe nearly adjacent rovibrational transitions of different isotopologues of CO2 near 2307 cm-1 permits sample measurement at low analyte pressures (as low as 2 Torr) for further sensitivity improvement. A novel method to reduce cw-fringing noise in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level after averaging 1,000 scans in 10 seconds. Detection limits down to the 20 picomoles have been observed, a concentration of approximately 400 ppm at 2 Torr in the waveguide with precision and accuracy at or better than 1 %. Improvements in detection and signal averaging electronics and laser power and mode quality are anticipated to reduce the required samples size to a 100-200 femtomoles of carbon. We report the application of the CAS system to a Laser Ablation-Catalytic-Combustion (LA-CC) micro-sampler system for selectively harvesting detailed sections of a solid surface for 13C analysis. This technique results in a three order of magnitude sensitivity improvement reported for our isotope measurement system compared to typical IRMS, providing new opportunities for making detailed investigations into wide ranges of microbial, physical, and chemical systems. The CAS is interfaced directly to the LA CC system currently operating at a 50 μm spatial resolution. We demonstrate that particulates produced by a Nd:YAG laser (λ=266nm) are isotopically homogenous with the parent material as measured by both IRMS and the CAS system. An improved laser ablation system operating at 193 nm with a spatial resolution of 2 microns or better is under development which will demonstrate the utility of the CAS system for sample sizes too low for IRMS. The improved sensitivities and optimized spatial targeting of such a system could interrogate targets as detailed as small cell clusters or intergrain organic deposits and could enhance ability to track biogeochemical carbon cycling.

Capillary Rise: Validity of the Dynamic Contact Angle Models.

PubMed

Wu, Pingkeng; Nikolov, Alex D; Wasan, Darsh T

2017-08-15

The classical Lucas-Washburn-Rideal (LWR) equation, using the equilibrium contact angle, predicts a faster capillary rise process than experiments in many cases. The major contributor to the faster prediction is believed to be the velocity dependent dynamic contact angle. In this work, we investigated the dynamic contact angle models for their ability to correct the dynamic contact angle effect in the capillary rise process. We conducted capillary rise experiments of various wetting liquids in borosilicate glass capillaries and compared the model predictions with our experimental data. The results show that the LWR equations modified by the molecular kinetic theory and hydrodynamic model provide good predictions on the capillary rise of all the testing liquids with fitting parameters, while the one modified by Joos' empirical equation works for specific liquids, such as silicone oils. The LWR equation modified by molecular self-layering model predicts well the capillary rise of carbon tetrachloride, octamethylcyclotetrasiloxane, and n-alkanes with the molecular diameter or measured solvation force data. The molecular self-layering model modified LWR equation also has good predictions on the capillary rise of silicone oils covering a wide range of bulk viscosities with the same key parameter W(0), which results from the molecular self-layering. The advantage of the molecular self-layering model over the other models reveals the importance of the layered molecularly thin wetting film ahead of the main meniscus in the energy dissipation associated with dynamic contact angle. The analysis of the capillary rise of silicone oils with a wide range of bulk viscosities provides new insights into the capillary dynamics of polymer melts.

Production of microbubbles from axisymmetric flow focusing in the jetting regime for moderate Reynolds numbers.

PubMed

Vega, E J; Acero, A J; Montanero, J M; Herrada, M A; Gañán-Calvo, A M

2014-06-01

We analyze both experimentally and numerically the formation of microbubbles in the jetting regime reached when a moderately viscous liquid stream focuses a gaseous meniscus inside a converging micronozzle. If the total (stagnation) pressure of the injected gas current is fixed upstream, then there are certain conditions on which a quasisteady gas meniscus forms. The meniscus tip is sharpened by the liquid stream down to the gas molecular scale. On the other side, monodisperse collections of microbubbles can be steadily produced in the jetting regime if the feeding capillary is appropriately located inside the nozzle. In this case, the microbubble size depends on the feeding capillary position. The numerical simulations for an imposed gas flow rate show that a recirculation cell appears in the gaseous meniscus for low enough values of that parameter. The experiments allow one to conclude that the bubble pinch-off comprises two phases: (i) a stretching motion of the precursor jet where the neck radius versus the time before the pinch essentially follows a potential law, and (ii) a final stage where a very thin and slender gaseous thread forms and eventually breaks apart into a number of micron-sized bubbles. Because of the difference between the free surface and core velocities, the gaseous jet breakage differs substantially from that of liquid capillary jets and gives rise to bubbles with diameters much larger than those expected from the Rayleigh-type capillary instability. The dependency of the bubble diameter upon the flow-rate ratio agrees with the scaling law derived by A. M. Gañán-Calvo [Phys. Rev. E 69, 027301 (2004)], although a slight influence of the Reynolds number can be observed in our experiments.

Miniaturized flow injection analysis system

DOEpatents

Folta, James A.

1997-01-01

A chemical analysis technique known as flow injection analysis, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38.times.25.times.3 mm, but can be designed for gas analysis and be substantially smaller in construction.

Exploring the effect of nested capillaries on core-cladding mode resonances in hollow-core antiresonant fibers

NASA Astrophysics Data System (ADS)

Provino, Laurent; Taunay, Thierry

2018-02-01

Optimal suppression of higher-order modes (HOMs) in hollow-core antiresonant fibers comprising a single ring of thin-walled capillaries was previously studied, and can be achieved when the condition on the capillary-tocore diameter ratio is satisfied (d/D ≍ 0.68). Here we report on the conditions for maximizing the leakage losses of HOMs in hollow-core nested antiresonant node-less fibers, while preserving low confinement loss for the fundamental mode. Using an analytical model based on coupled capillary waveguides, as well as full-vector finite element modeling, we show that optimal d/D value leading to high leakage losses of HOMs, is strongly correlated to the size of nested capillaries. We also show that extremely high value of degree of HOM suppression (˜1200) at the resonant coupling is almost unchanged on a wide range of nested capillary diameter dN ested values. These results thus suggest the possibility of designing antiresonant fibers with nested elements, which show optimal guiding performances in terms of the HOM loss compared to that of the fundamental mode, for clearly defined paired values of the ratios dN ested/d and d/D. These can also tend towards a single-mode behavior only when the dimensionless parameter dN ested/d is less than 0.30, with identical wall thicknesses for all of the capillaries.

Simultaneous determination of caffeine, paracetamol, and ibuprofen in pharmaceutical formulations by high-performance liquid chromatography with UV detection and by capillary electrophoresis with conductivity detection.

PubMed

Cunha, Rafael R; Chaves, Sandro C; Ribeiro, Michelle M A C; Torres, Lívia M F C; Muñoz, Rodrigo A A; Dos Santos, Wallans T P; Richter, Eduardo M

2015-05-01

Paracetamol, caffeine and ibuprofen are found in over-the-counter pharmaceutical formulations. In this work, we propose two new methods for simultaneous determination of paracetamol, caffeine and ibuprofen in pharmaceutical formulations. One method is based on high-performance liquid chromatography with diode-array detection and the other on capillary electrophoresis with capacitively coupled contactless conductivity detection. The separation by high-performance liquid chromatography with diode-array detection was achieved on a C18 column (250×4.6 mm(2), 5 μm) with a gradient mobile phase comprising 20-100% acetonitrile in 40 mmol L(-1) phosphate buffer pH 7.0. The separation by capillary electrophoresis with capacitively coupled contactless conductivity detection was achieved on a fused-silica capillary (40 cm length, 50 μm i.d.) using 10 mmol L(-1) 3,4-dimethoxycinnamate and 10 mmol L(-1) β-alanine with pH adjustment to 10.4 with lithium hydroxide as background electrolyte. The determination of all three pharmaceuticals was carried out in 9.6 min by liquid chromatography and in 2.2 min by capillary electrophoresis. Detection limits for caffeine, paracetamol and ibuprofen were 4.4, 0.7, and 3.4 μmol L(-1) by liquid chromatography and 39, 32, and 49 μmol L(-1) by capillary electrophoresis, respectively. Recovery values for spiked samples were between 92-107% for both proposed methods. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wavelength selective switch array employing silica-based waveguide frontend with integrated polarization diversity optics.

PubMed

Sakamaki, Yohei; Shikama, Kota; Ikuma, Yuichiro; Suzuki, Kenya

2017-08-21

We propose a waveguide frontend with integrated polarization diversity optics for a wavelength selective switch (WSS) array with a liquid crystal on silicon switching engine to simplify the free space optics configuration and the alignment process in optical modules. The polarization diversity function is realized by the integration of a waveguide-type polarization beam splitter and a polarization rotating half-wave plate in a beam launcher using silica-based planar lightwave circuit technology. We confirmed experimentally the feasibility of using our proposed waveguide frontend in a two-in-one 1 × 20 WSS. The experimental results show that the fabricated waveguide frontend provides a polarization diversity function without any degradation in optical performance.

HOT ELUENT CAPILLARY LIQUID CHROMATOGRAPHY USING ZIRCONIA AND TITANIA BASED STATIONARY PHASES. (R825344)

EPA Science Inventory

Abstract

High speed capillary liquid chromatographic separations using a simple home made system constructed from readily available inexpensive components have been studied. Using thermally stable zirconia and titania based packing, the separation of eight alkylbenzene...

A Capillary Absorption Spectrometer for Stable Carbon Isotope Ratio (13C/12C) Analysis in Very Small Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, James F.; Sams, Robert L.; Blake, Thomas A.

2012-02-06

A capillary absorption spectrometer (CAS) suitable for IR laser isotope analysis of small CO{sub 2} samples is presented. The system employs a continuous-wave (cw) quantum cascade laser to study nearly adjacent rovibrational transitions of different isotopologues of CO{sub 2} near 2307 cm{sup -1} (4.34 {mu}m). This initial CAS system can achieve relative isotopic precision of about 10 ppm {sup 13}C, or {approx}1{per_thousand} (per mil in delta notation relative to Vienna Pee Dee Belemnite) with 20-100 picomoles of entrained sample within the hollow waveguide for CO{sub 2} concentrations {approx}400 to 750 ppm. Isotopic analyses of such gas fills in a 1-mmmore » ID hollow waveguide of 0.8 m overall physical path length can be carried out down to {approx}2 Torr. Overall {sup 13}C/{sup 12}C ratios can be calibrated to {approx}2{per_thousand} accuracy with diluted CO{sub 2} standards. A novel, low-cost method to reduce cw-fringing noise resulting from multipath distortions in the hollow waveguide is presented, which allows weak absorbance features to be studied at the few ppm level (peak-to-rms) after 1,000 scans are co-added in {approx}10 sec. The CAS is meant to work directly with converted CO{sub 2} samples from a Laser Ablation-Catalytic-Combustion (LA CC) micro-sampler to provide {sup 13}C/{sup 12}C ratios of small biological isolates with spatial resolutions {approx}50 {mu}m.« less

Optofluidic devices for biomolecule sensing and multiplexing

NASA Astrophysics Data System (ADS)

Ozcelik, Damla

Optofluidics which integrates photonics and microfluidics, has led to highly compact, sensitive and adaptable biomedical sensors. Optofluidic biosensors based on liquid-core anti-resonant reflecting optical waveguides (LC-ARROWs), have proven to be a highly sensitive, portable, and reconfigurable platform for fluorescence spectroscopy and detection of single biomolecules such as proteins, nucleic acids, and virus particles. However, continued improvements in sensitivity remain a major goal as we approach the ultimate limit of detecting individual bio-particles labeled by single or few fluorophores. Additionally, the ability to simultaneously detect and identify multiple biological particles or biomarkers is one of the key requirements for molecular diagnostic tests. The compactness and adaptability of these platforms can further be advanced by introducing tunability, integrating off-chip components, designing reconfigurable and customizable devices, which makes these platforms very good candidates for many different applications. The goal of this thesis was to introduce new elements in these LC-ARROW optofluidics platforms that provide major enhancements in their functionality, making them more sensitive, compact, customizable and multiplexed. First, a novel integrated tunable spectral filter that achieves effective elimination of background noise on the ARROW platform was demonstrated. A unique dual liquid-core design enabled the independent multi-wavelength tuning of the spectral filter by adjusting the refractive index and chemical properties of the liquid. In order to enhance the detection sensitivity of the platform, Y-splitter waveguides were integrated to create multiple excitation spots for each target molecule. A powerful signal processing algorithm was used to analyze the data to improve the signal-to-noise ratio (SNR) of the collected data. Next, the design, optimization and characterization of the Y-splitter waveguides are presented; and single influenza virus detection with an improved SNR was demonstrated using this platform. Finally, multiplexing capacity is introduced to the ARROW detection platform by integrating multi-mode interference (MMI) waveguides. MMI waveguides create wavelength dependent multiple excitation spots at the excitation region, allowing the spectral multiplexed detection of multiple different target molecules based on the excitation pattern, without the need for additional spectral filters. Successful spectral multiplexed detection of three different types of influenza viruses is achieved by using separate wavelengths and combination of wavelengths. This multiplexing capacity is further enhanced by taking advantage of the spatial properties of the MMI pattern, designing triple liquid-core waveguides that intersect the MMI waveguide in different locations. Furthermore, the spectral and spatial multiplexing capacities are combined in these triple liquid-core MMI platforms, allowing these devices to distinguish multiple different targets and samples simultaneously.

Direct numerical simulation of gas-solid-liquid flows with capillary effects: An application to liquid bridge forces between spherical particles.

PubMed

Sun, Xiaosong; Sakai, Mikio

2016-12-01

In this study, a numerical method is developed to perform the direct numerical simulation (DNS) of gas-solid-liquid flows involving capillary effects. The volume-of-fluid method employed to track the free surface and the immersed boundary method is adopted for the fluid-particle coupling in three-phase flows. This numerical method is able to fully resolve the hydrodynamic force and capillary force as well as the particle motions arising from complicated gas-solid-liquid interactions. We present its application to liquid bridges among spherical particles in this paper. By using the DNS method, we obtain the static bridge force as a function of the liquid volume, contact angle, and separation distance. The results from the DNS are compared with theoretical equations and other solutions to examine its validity and suitability for modeling capillary bridges. Particularly, the nontrivial liquid bridges formed in triangular and tetrahedral particle clusters are calculated and some preliminary results are reported. We also perform dynamic simulations of liquid bridge ruptures subject to axial stretching and particle motions driven by liquid bridge action, for which accurate predictions are obtained with respect to the critical rupture distance and the equilibrium particle position, respectively. As shown through the simulations, the strength of the present method is the ability to predict the liquid bridge problem under general conditions, from which models of liquid bridge actions may be constructed without limitations. Therefore, it is believed that this DNS method can be a useful tool to improve the understanding and modeling of liquid bridges formed in complex gas-solid-liquid flows.

Precise dielectric property measurements and E-field probe calibration for specific absorption rate measurements using a rectangular waveguide

PubMed Central

Hakim, B M; Beard, B B; Davis, C C

2018-01-01

Specific absorption rate (SAR) measurements require accurate calculations of the dielectric properties of tissue-equivalent liquids and associated calibration of E-field probes. We developed a precise tissue-equivalent dielectric measurement and E-field probe calibration system. The system consists of a rectangular waveguide, electric field probe, and data control and acquisition system. Dielectric properties are calculated using the field attenuation factor inside the tissue-equivalent liquid and power reflectance inside the waveguide at the air/dielectric-slab interface. Calibration factors were calculated using isotropicity measurements of the E-field probe. The frequencies used are 900 MHz and 1800 MHz. The uncertainties of the measured values are within ±3%, at the 95% confidence level. Using the same waveguide for dielectric measurements as well as calibrating E-field probes used in SAR assessments eliminates a source of uncertainty. Moreover, we clearly identified the system parameters that affect the overall uncertainty of the measurement system. PMID:29520129

The Determination of Pesticidal and Non-Pesticidal Organotin Compounds by in situ Ethylation and Capillary Gas Chromatography with Pulsed Flame Photometric Detection

EPA Science Inventory

The concurrent determination of pesticidal and non-pesticidal organotin compounds in several water matrices, using a simultaneous in situ ethylation and liquid-liquid extraction followed by splitless injection mode capillary gas chromatography with pulsed flame photometric detect...

Use of Plastic Capillaries for Macromolecular Crystallization

NASA Technical Reports Server (NTRS)

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

2003-01-01

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

Exact Solution for Capillary Bridges Properties by Shooting Method

NASA Astrophysics Data System (ADS)

Qiang-Nian, Li; Jia-Qi, Zhang; Feng-Xi, Zhou

2017-04-01

The investigation of liquid bridge force acting between wet particles has great significance in many fields. In this article, the exact solution of capillary force between two unequal-sized spherical particles is investigated. Firstly, The Young-Laplace equation with moving boundary is converted into a set of ordinary differential equations with two fix point boundary using variable substitution technique, in which the gravity effects have been neglected. The geometry of the liquid bridge between two particles is solved by shooting method. After that, the gorge method is applied to calculate the capillary-bridge force that is consists of contributions from the capillary suction and surface tension. Finally, the effect of various parameters including distance between two spheres, radii of spheres, and contact angles on the capillary force are investigated. It is shown that the presented approach is an efficient and accurate algorithm for capillary force between two particles in complex situations.

Determination of gas-liquid partition coefficients of several organic solutes in trihexyl(tetradecyl)phosphonium bromide using capillary gas chromatography columns.

PubMed

Ronco, Nicolás R; Menestrina, Fiorella; Romero, Lílian M; Castells, Cecilia B

2017-06-09

In this paper, we report gas-liquid partition constants for thirty-five volatile organic solutes in the room temperature ionic liquid trihexyl(tetradecyl)phosphonium bromide measured by gas-liquid chromatography using capillary columns. The relative contribution of gas-liquid partition and interfacial adsorption to retention was evaluated through the use of columns with different the phase ratio. Four capillary columns with exactly known phase ratios were constructed and employed to measure the solute retention factors at four temperatures between 313.15 and 343.15K. The partition coefficients were calculated from the slopes of the linear regression between solute retention factors and the reciprocal of phase ratio at a given temperature according to the gas-liquid chromatographic theory. Gas-liquid interfacial adsorption was detected for a few solutes and it has been considered for the calculations of partition coefficient. Reliable solute's infinite dilution activity coefficients can be obtained when retention data are determined by a unique partitioning mechanism. The partial molar excess enthalpies at infinite dilution have been estimated from the dependence of experimental values of solute activity coefficients with the column temperature. A thorough discussion of the uncertainties of the experimental measurements and the main advantages of the use of capillary columns to acquire the aforementioned relevant thermodynamic information was performed. Copyright © 2017 Elsevier B.V. All rights reserved.

A sensitive flow-batch system for on board determination of ultra-trace ammonium in seawater: Method development and shipboard application.

PubMed

Zhu, Yong; Yuan, Dongxing; Huang, Yongming; Ma, Jian; Feng, Sichao

2013-09-10

Combining fluorescence detection with flow analysis and solid phase extraction (SPE), a highly sensitive and automatic flow system for measurement of ultra-trace ammonium in open ocean water was established. Determination was based on fluorescence detection of a typical product of o-phthaldialdehyde and ammonium. In this study, the fluorescence reaction product could be efficiently extracted onto an SPE cartridge (HLB, hydrophilic-lipophilic balance). The extracted fluorescence compounds were rapidly eluted with ethanol and directed into a flow cell for fluorescence detection. Compared with the common used fluorescence method, the proposed one offered the benefits of improved sensitivity, reduced reagent consumption, negligible salinity effect and lower cost. Experimental parameters were optimized using a univariate experimental design. Calibration curves, ranging from 1.67 to 300nM, were obtained with different reaction times. The recoveries were between 89.5 and 96.5%, and the detection limits in land-based and shipboard laboratories were 0.7 and 1.2nM, respectively. The relative standard deviation was 3.5% (n=5) for an aged seawater sample spiked with 20nM ammonium. Compared with the analytical results obtained using the indophenol blue method coupled to a long-path liquid waveguide capillary cell, the proposed method showed good agreement. The method had been applied on board during a South China Sea cruise in August 2012. A vertical profile of ammonium in the South East Asia Time-Series (SEATS, 18° N, 116° E) station was produced. The distribution of ammonium in the surface seawater of the Qiongdong upwelling in South China Sea is also presented. Copyright © 2013 Elsevier B.V. All rights reserved.

Novel cryogenic sources for liquid droplet and solid filament beams

NASA Astrophysics Data System (ADS)

Grams, Michael P.

Two novel atomic and molecular beam sources have been created and tested consisting first of a superfluid helium liquid jet, and secondly a solid filament of argon. The superfluid helium apparatus is the second of its kind in the world and uses a modified liquid helium cryostat to inject a cylindrical stream of superfluid helium into vacuum through glass capillary nozzles with diameters on the order of one micron created on-site at Arizona State University. The superfluid beam is an entirely new way to study superfluid behavior, and has many new applications such as superfluid beam-surface scattering, beam-beam scattering, and boundary-free study of superfluidity. The solid beam of argon is another novel beam source created by flowing argon gas through a capillary 50 microns in diameter which is clamped by a small copper plate to a copper block kept at liquid nitrogen temperature. The gas subsequently cools and solidifies plugging the capillary. Upon heating, the solid plug melts and liquid argon exits the capillary and immediately freezes by evaporative cooling. The solid filaments may find application as wall-less cryogenic matrices, or targets for laser plasma sources of extreme UV and soft x-ray sources.

Capillary Flow Layer-by-Layer: A Microfluidic Platform for the High-Throughput Assembly and Screening of Nanolayered Film Libraries

PubMed Central

2015-01-01

Layer-by-layer (LbL) assembly is a powerful tool with increasing real world applications in energy, biomaterials, active surfaces, and membranes; however, the current state of the art requires individual sample construction using large quantities of material. Here we describe a technique using capillary flow within a microfluidic device to drive high-throughput assembly of LbL film libraries. This capillary flow layer-by-layer (CF-LbL) method significantly reduces material waste, improves quality control, and expands the potential applications of LbL into new research spaces. The method can be operated as a simple lab benchtop apparatus or combined with liquid-handling robotics to extend the library size. Here we describe and demonstrate the technique and establish its ability to recreate and expand on the known literature for film growth and morphology. We use the same platform to assay biological properties such as cell adhesion and proliferation and ultimately provide an example of the use of this approach to identify LbL films for surface-based DNA transfection of commonly used cell types. PMID:24836460

Recent advances in monolithic columns for protein and peptide separation by capillary liquid chromatography.

PubMed

Liang, Yu; Zhang, Lihua; Zhang, Yukui

2013-03-01

Capillary liquid chromatography (cLC) has great potential for protein and peptide separation, with advantages of high efficiency, high resolution, low sample consumption, and high sensitivity when coupled with mass spectrometry. In recent years, monoliths have been widely used as the stationary phases for capillary columns, owing to easy preparation, high permeability, fast mass transfer, and low backpressure. This review summarizes recent advances (2007-2012) in monolithic columns for protein and peptide separation by cLC. After a brief introduction on the preparation of monolithic capillary columns, the emphasis of this review is focused on the recent application of such columns for protein and peptide separation by cLC. Furthermore, the challenges and potential hot points of monolithic capillary columns in the future are discussed.

Manipulating femtosecond pulse shape using liquid crystals infiltrated one-dimensional graded index photonic crystal waveguides composed of coupled-cavities

NASA Astrophysics Data System (ADS)

Fathollahi Khalkhali, T.; Bananej, A.

2017-10-01

In this paper, we investigate the transmission of a 10-femtosecond pulse through an ordinary and graded index coupled-cavity waveguide, using finite-difference time-domain and transfer matrix method. The ordinary structure is composed of dielectric/liquid crystal layers in which four defect layers are placed symmetrically. Next, we introduce a graded structure based on the ordinary system in which dielectric refractive index slightly increases with a constant step value from the beginning to the end of the structure while liquid crystal layers are maintained unchanged. Simulation results reveal that by applying an external static electric field and controlling liquid crystal refractive index in graded structure, it is possible to transmit an ultrashort pulse with negligible distortion and attenuation.

Hardening of particle/oil/water suspensions due to capillary bridges: Experimental yield stress and theoretical interpretation.

PubMed

Danov, Krassimir D; Georgiev, Mihail T; Kralchevsky, Peter A; Radulova, Gergana M; Gurkov, Theodor D; Stoyanov, Simeon D; Pelan, Eddie G

2018-01-01

Suspensions of colloid particles possess the remarkable property to solidify upon the addition of minimal amount of a second liquid that preferentially wets the particles. The hardening is due to the formation of capillary bridges (pendular rings), which connect the particles. Here, we review works on the mechanical properties of such suspensions and related works on the capillary-bridge force, and present new rheological data for the weakly studied concentration range 30-55 vol% particles. The mechanical strength of the solidified capillary suspensions, characterized by the yield stress Y, is measured at the elastic limit for various volume fractions of the particles and the preferentially wetting liquid. A quantitative theoretical model is developed, which relates Y with the maximum of the capillary-bridge force, projected on the shear plane. A semi-empirical expression for the mean number of capillary bridges per particle is proposed. The model agrees very well with the experimental data and gives a quantitative description of the yield stress, which increases with the rise of interfacial tension and with the volume fractions of particles and capillary bridges, but decreases with the rise of particle radius and contact angle. The quantitative description of capillary force is based on the exact theory and numerical calculation of the capillary bridge profile at various bridge volumes and contact angles. An analytical formula for Y is also derived. The comparison of the theoretical and experimental strain at the elastic limit reveals that the fluidization of the capillary suspension takes place only in a deformation zone of thickness up to several hundred particle diameters, which is adjacent to the rheometer's mobile plate. The reported experimental results refer to water-continuous suspension with hydrophobic particles and oily capillary bridges. The comparison of data for bridges from soybean oil and hexadecane surprisingly indicate that the yield strength is greater for the suspension with soybean oil despite its lower interfacial tension against water. The result can be explained with the different contact angles of the two oils in agreement with the theoretical predictions. The results could contribute for a better understanding, quantitative prediction and control of the mechanical properties of three-phase capillary suspensions solid/liquid/liquid. Copyright © 2017 Elsevier B.V. All rights reserved.

Ionic Liquids in HPLC and CE: A Hope for Future.

PubMed

Ali, Imran; Suhail, Mohd; Sanagi, Mohd Marsin; Aboul-Enein, Hassan Y

2017-07-04

The ionic liquids (ILs) are salts with melting points below 100°C. These are called as ionic fluids, ionic melts, liquid electrolytes, fused salts, liquid salts, ionic glasses, designer solvents, green solvents and solvents of the future. These have a wide range of applications, including medical, pharmaceutical and chemical sciences. Nowadays, their use is increasing greatly in separation science, especially in chromatography and capillary electrophoresis due to their remarkable properties. The present article describes the importance of ILs in high-performance liquid chromatography and capillary electrophoresis. Efforts were also made to highlight the future expectations of ILs.

Respiratory fluid mechanics

NASA Astrophysics Data System (ADS)

Grotberg, James B.

2011-02-01

This article covers several aspects of respiratory fluid mechanics that have been actively investigated by our group over the years. For the most part, the topics involve two-phase flows in the respiratory system with applications to normal and diseased lungs, as well as therapeutic interventions. Specifically, the topics include liquid plug flow in airways and at airway bifurcations as it relates to surfactant, drug, gene, or stem cell delivery into the lung; liquid plug rupture and its damaging effects on underlying airway epithelial cells as well as a source of crackling sounds in the lung; airway closure from "capillary-elastic instabilities," as well as nonlinear stabilization from oscillatory core flow which we call the "oscillating butter knife;" liquid film, and surfactant dynamics in an oscillating alveolus and the steady streaming, and surfactant spreading on thin viscous films including our discovery of the Grotberg-Borgas-Gaver shock.

Numerical modelling and experimental study of liquid evaporation during gel formation

NASA Astrophysics Data System (ADS)

Pokusaev, B. G.; Khramtsov, D. P.

2017-11-01

Gels are promising materials in biotechnology and medicine as a medium for storing cells for bioprinting applications. Gel is a two-phase system consisting of solid medium and liquid phase. Understanding of a gel structure evolution and gel aging during liquid evaporation is a crucial step in developing new additive bioprinting technologies. A numerical and experimental study of liquid evaporation was performed. In experimental study an evaporation process of an agarose gel layer located on Petri dish was observed and mass difference was detected using electronic scales. Numerical model was based on a smoothed particle hydrodynamics method. Gel in a model was represented as a solid-liquid system and liquid evaporation was modelled due to capillary forces and heat transfer. Comparison of experimental data and numerical results demonstrated that model can adequately represent evaporation process in agarose gel.

Miniaturized flow injection analysis system

DOEpatents

Folta, J.A.

1997-07-01

A chemical analysis technique known as flow injection analysis is described, wherein small quantities of chemical reagents and sample are intermixed and reacted within a capillary flow system and the reaction products are detected optically, electrochemically, or by other means. A highly miniaturized version of a flow injection analysis system has been fabricated utilizing microfabrication techniques common to the microelectronics industry. The microflow system uses flow capillaries formed by etching microchannels in a silicon or glass wafer followed by bonding to another wafer, commercially available microvalves bonded directly to the microflow channels, and an optical absorption detector cell formed near the capillary outlet, with light being both delivered and collected with fiber optics. The microflow system is designed mainly for analysis of liquids and currently measures 38{times}25{times}3 mm, but can be designed for gas analysis and be substantially smaller in construction. 9 figs.

A liquid chromatographic method for determination of theophylline in serum and capillary blood--a comparison.

PubMed

Gartzke, J; Jäger, H; Vins, I

1991-01-01

A simple, fast and reliable liquid chromatographic method for the determination of theophylline in serum and capillary blood after a solid phase extraction is described for therapeutic drug monitoring. The employment of capillary blood permits the determination of an individual drug profile and other pharmacokinetic studies in neonates and infants. There were no differences in venous- and capillary-blood levels but these values compared poorly with those in serum. An adjustment of the results by correction of the different volumes of serum and blood by haematocrit was unsuccessful. Differences in the binding of theophylline to erythrocytes could be an explanation for the differences in serum at blood levels of theophylline.

Love-Wave Biosensors Using Cross-Linked Polymer Waveguides on LiTaO{sub 3} Substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

BENDER,FLORIAN; CERNOSEK,RICHARD W.; JOSSE,F.

The design and performance of Love-wave sensors using cross-linked poly-(methyl methacrylate) waveguides of thickness of 0.3--3.2 {micro}m on LiTaO{sub 3} substrates are described. It is found that this layer-substrate combination provides sufficient waveguidance, and electrical isolation of the IDTs from the liquid environment to achieve low acoustic loss and distortion. In bio-sensing experiments, mass sensitivity up to 1,420 Hz/(ng/mm{sup 2}) is demonstrated.

Nanowires and nanoribbons as subwavelength optical waveguides and their use as components in photonic circuits and devices

DOEpatents

Yang, Peidong; Law, Matt; Sirbuly, Donald J.; Johnson, Justin C.; Saykally, Richard; Fan, Rong; Tao, Andrea

2012-10-02

Nanoribbons and nanowires having diameters less than the wavelength of light are used in the formation and operation of optical circuits and devices. Such nanostructures function as subwavelength optical waveguides which form a fundamental building block for optical integration. The extraordinary length, flexibility and strength of these structures enable their manipulation on surfaces, including the precise positioning and optical linking of nanoribbon/wire waveguides and other nanoribbon/wire elements to form optical networks and devices. In addition, such structures provide for waveguiding in liquids, enabling them to further be used in other applications such as optical probes and sensors.

Ripplon laser through stimulated emission mediated by water waves

NASA Astrophysics Data System (ADS)

Kaminski, Samuel; Martin, Leopoldo L.; Maayani, Shai; Carmon, Tal

2016-12-01

Lasers rely on stimulated electronic transition, a quantum phenomenon in the form of population inversion. In contrast, phonon masers depend on stimulated Raman scattering and are entirely classical. Here we extend Raman lasers to rely on capillary waves, which are unique to the liquid phase of matter and relate to the attraction between intimate fluid particles. We fabricate resonators that co-host capillary and optical modes, control them to operate at their non-resolved sideband and observe stimulated capillary scattering and the coherent excitation of capillary resonances at kilohertz rates (which can be heard in audio files recorded by us). By exchanging energy between electromagnetic and capillary waves, we bridge the interfacial tension phenomena at the liquid phase boundary to optics. This approach may impact optofluidics by allowing optical control, interrogation and cooling of water waves.

Separation of flavonol-2-O-glycosides from Calendula officinalis and Sambucus nigra by high-performance liquid and micellar electrokinetic capillary chromatography.

PubMed

Pietta, P; Bruno, A; Mauri, P; Rava, A

1992-02-28

Calendula officinalis and Sambucus nigra flowers were analysed by reversed-phase high-performance liquid chromatography (RP-HPLC) and micellar electrokinetic capillary chromatography (MECC). RP-HPLC was performed on C8 Aquapore RP 300 columns with eluents containing 2-propanol and tetrahydrofuran. MECC was carried out on a 72-cm fused-silica capillary using sodium dodecyl sulphate and sodium borate (pH 8.3) as the running buffer. The results obtained by these techniques are compared.

A novel pneumatic micropipette aspiration method using a balance pressure model.

PubMed

Zhao, Qili; Wu, Ming; Cui, Maosheng; Qin, Yanding; Yu, Jin; Sun, Mingzhu; Zhao, Xin; Feng, Xizeng

2013-12-01

This paper presents a novel micropipette aspiration (MA) method based on a common pneumatic micro-injection system. This method is the first to quantify the influence of capillary effect on aspiration pressure using a balance pressure model, and in return, uses the capillary effect to quantify the aspiration pressure. Subsequently, the seal between the cell and the micropipette is detected to judge and exclude the ineffective MA attempts. The rationality of the balance pressure model is validated by the designed micropipette-filling experiments. Through applied to elasticity-determination of the cells with different sizes, the feasibility and versatility of this MA method are proved. With abilities to quantify aspiration pressures and detect the seam between the cell and the micropipette, our method is expected to advance the application of the commercial pneumatic injector in the MA of cells. Moreover, with the quantified volume of the liquid entering into the micropipette during MA process, our method also has a potential applicability to the study of the permeability of the cell membrane in the future.

Maximal liquid bridges between horizontal cylinders

NASA Astrophysics Data System (ADS)

Cooray, Himantha; Huppert, Herbert E.; Neufeld, Jerome A.

2016-08-01

We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces owing to surface tension and hydrostatic pressure that balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can be approximated with simple relationships when the radius of the cylinders is small compared with the capillary length. For such small cylinders, liquid bridges with the largest cross-sectional area occur when the centre-to-centre distance between the cylinders is approximately twice the capillary length. The maximum trapping capacity for a pair of cylinders at a given separation is linearly related to the separation when it is small compared with the capillary length. The meniscus slope angle of the largest liquid bridge produced in this regime is also a linear function of the separation. We additionally derive approximate solutions for the profile of a liquid bridge, using the linearized Laplace-Young equation. These solutions analytically verify the above-mentioned relationships obtained for the maximization of the trapping capacity.

An apparatus with a horizontal capillary tube intended for measurement of the surface tension of supercooled liquids

NASA Astrophysics Data System (ADS)

Vinš, Václav; Hošek, Jan; Hykl, Jiří; Hrubý, Jan

2015-05-01

New experimental apparatus for measurement of the surface tension of liquids under the metastable supercooled state has been designed and assembled in the study. The measuring technique is similar to the method employed by P.T. Hacker [NACA TN 2510] in 1951. A short liquid thread of the liquid sample was sucked inside a horizontal capillary tube partly placed in a temperature-controlled glass chamber. One end of the capillary tube was connected to a setup with inert gas which allowed for precise tuning of the gas overpressure in order of hundreds of Pa. The open end of the capillary tube was precisely grinded and polished before the measurement in order to assure planarity and perpendicularity of the outer surface. The liquid meniscus at the open end was illuminated by a laser beam and observed by a digital camera. Application of an increasing overpressure of the inert gas at the inner meniscus of the liquid thread caused variation of the outer meniscus such that it gradually changed from concave to flat and subsequently convex shape. The surface tension at the temperature of the inner meniscus could be evaluated from the overpressure corresponding to exactly planar outer meniscus. Detailed description of the new setup together with results of the preliminary tests is provided in the study.

Flow cytometry without alignment of collection optics.

PubMed

Sitton, Greg; Srienc, Friedrich

2009-12-01

This study describes the performance of a new waveguide flow cell constructed from Teflon AF (TFC) and the potential use of fiber optic splitters to replace collection objectives and dichroic mirrors. The TFC has the unique optical property that the refractive index of the polymer is lower than water and therefore, water filled TFC behaves and functions as a liquid core waveguide. Thus, as cells flow through the TFC and are illuminated by a laser orthogonal to the flow direction, scattered and fluorescent light is directed down the axis of the TFC to a fiber optic. The total signal in the fiber optic is then split into multiple fibers by fiber optic splitters to enable measurement of signal intensities at different wavelengths. Optical filters are placed at the terminus of each fiber before measurement of specific wavelengths by a PMT. The constructed system was used to measure DNA content of CHO and yeast cells. Polystyrene beads were used for alignment and to assess the performance of the system. Polystyrene beads were observed to produce light scattering signals with unique bimodal characteristics dependent on the direction of flow relative to the collecting fiber optic.

Spectroscopic chemical analysis methods and apparatus

NASA Technical Reports Server (NTRS)

Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor)

2013-01-01

Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

Capillary liquid chromatographic analysis of fat-soluble vitamins and beta-carotene in combination with in-tube solid-phase microextraction.

PubMed

Xu, Hui; Jia, Li

2009-01-01

A capillary liquid chromatography (CLC) system with UV/vis detection was coupled with an in-tube solid-phase microextraction (SPME) device for the analysis of fat-soluble vitamins and beta-carotene. A monolithic silica-ODS column was used as the extraction medium. An optical-fiber flow cell with a long light path in the UV/vis detector was utilized to further enhance the detection sensitivity. In the in-tube SPME/CLC system, the pre-condition of the extraction column and the effect of the injection volume were investigated. The detection limits (LOD) for the fat-soluble vitamins and beta-carotene were in the range from 1.9 to 173 ng/mL based on the signal-to-noise ratio of 3 (S/N=3). The relative standard deviations of migration time and peak area for each analyte were less than 5.0%. The method was applied to the analysis of fat-soluble vitamins and beta-carotene contents in corns.

Optically reconfigurable patterning for control of the propagation characteristics of a planar waveguide

NASA Astrophysics Data System (ADS)

Wang, Y.; Klittnick, A.; Clark, N. A.; Keller, P.

2008-10-01

We demonstrate an easily fabricated all-optical and freely reconfigurable method of controlling the propagating characteristics of the optic path within a planar waveguide with low insertion losses by employing the optical patterning of the refractive index of an erasable and rewriteable photosensitive liquid crystal polymer cladding layer.

Open-ended half-mode substrate integrated waveguide sensor with ground flange for complex permittivity measurement

USDA-ARS?s Scientific Manuscript database

A novel open-ended half-mode substrate integrated waveguide (HMSIW) sensor with ground flange for measuring complex permittivity of liquids, semisolids, and granular and particulate materials is presented. The open-ended HMSIW is designed and fabricated on FR4 substrate. The ground flange was custo...

Liquid sensing capability of rolled-up tubular optical microcavities: a theoretical study.

PubMed

Zhao, Fangyuan; Zhan, Tianrong; Huang, Gaoshan; Mei, Yongfeng; Hu, Xinhua

2012-10-07

Rolled-up tubular optical microcavities are a novel type of optical sensor for identifying different liquids and monitoring single cells. Based on a Mie scattering method, we systematically study the optical resonances and liquid sensing capability of microtubes. Analytical formulas are presented to calculate the resonant wavelengths λ(r), Q factors, sensitivities S and figures of merit QS. Both ideal and rolled-up microtubes are considered for different optical materials in tube walls (refractive indices ranging from 1.5 to 2.5) and for three setups: tube-in-liquid, hollow-tube-in-liquid and liquid-in-tube. It is found that for rolled-up microtubes, the highest QS can be achieved by using the liquid-in-tube setup and very thin wall thicknesses. A maximal sensitivity is found in the case of the liquid cylinder. Our theory well explains a recent experiment under the setup of tube-in-liquid. It is also found that, although it describes the case of tube-in-liquid well, the waveguide approximation approach is not suitable for the case of liquid-in-tube. The results could be useful to design better optofluidic devices based on rolled-up microtubes.

SELECTIVE TRACE ENRICHMENT BY IMMUNOAFFINITY CAPILLARY ELECTROCHROMATOGRAPHY ON-LINE WITH CAPILLARY ZONE ELECTROPHORESIS - LASER-INDUCED FLUORESCENCE

EPA Science Inventory

Limited by the lack of a sensitive, universal detector, many capillary-based liquid-phase separation techniques might benefit from techniques that overcome modest concentration sensitivity by preconcentrating large injection volumes. The work presented employs selective solid-ph...

Recent advances in capillary ultrahigh pressure liquid chromatography.

PubMed

Blue, Laura E; Franklin, Edward G; Godinho, Justin M; Grinias, James P; Grinias, Kaitlin M; Lunn, Daniel B; Moore, Stephanie M

2017-11-10

In the twenty years since its initial demonstration, capillary ultrahigh pressure liquid chromatography (UHPLC) has proven to be one of most powerful separation techniques for the analysis of complex mixtures. This review focuses on the most recent advances made since 2010 towards increasing the performance of such separations. Improvements in capillary column preparation techniques that have led to columns with unprecedented performance are described. New stationary phases and phase supports that have been reported over the past decade are detailed, with a focus on their use in capillary formats. A discussion on the instrument developments that have been required to ensure that extra-column effects do not diminish the intrinsic efficiency of these columns during analysis is also included. Finally, the impact of these capillary UHPLC topics on the field of proteomics and ways in which capillary UHPLC may continue to be applied to the separation of complex samples are addressed. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

Capillary Contact Angle in a Completely Wet Groove

NASA Astrophysics Data System (ADS)

Parry, A. O.; Malijevský, A.; Rascón, C.

2014-10-01

We consider the phase equilibria of a fluid confined in a deep capillary groove of width L with identical side walls and a bottom made of a different material. All walls are completely wet by the liquid. Using density functional theory and interfacial models, we show that the meniscus separating liquid and gas phases at two phase capillary coexistence meets the bottom capped end of the groove at a capillary contact angle θcap(L) which depends on the difference between the Hamaker constants. If the bottom wall has a weaker wall-fluid attraction than the side walls, then θcap>0 even though all the isolated walls are themselves completely wet. This alters the capillary condensation transition which is now first order; this would be continuous in a capped capillary made wholly of either type of material. We show that the capillary contact angle θcap(L) vanishes in two limits, corresponding to different capillary wetting transitions. These occur as the width (i) becomes macroscopically large, and (ii) is reduced to a microscopic value determined by the difference in Hamaker constants. This second wetting transition is characterized by large scale fluctuations and essential critical singularities arising from marginal interfacial interactions.

Distributed coupling and multi-frequency microwave accelerators

DOEpatents

Tantawi, Sami G.; Li, Zenghai; Borchard, Philipp

2016-07-05

A microwave circuit for a linear accelerator has multiple metallic cell sections, a pair of distribution waveguide manifolds, and a sequence of feed arms connecting the manifolds to the cell sections. The distribution waveguide manifolds are connected to the cell sections so that alternating pairs of cell sections are connected to opposite distribution waveguide manifolds. The distribution waveguide manifolds have concave modifications of their walls opposite the feed arms, and the feed arms have portions of two distinct widths. In some embodiments, the distribution waveguide manifolds are connected to the cell sections by two different types of junctions adapted to allow two frequency operation. The microwave circuit may be manufactured by making two quasi-identical parts, and joining the two parts to form the microwave circuit, thereby allowing for many manufacturing techniques including electron beam welding, and thereby allowing the use of un-annealled copper alloys, and hence greater tolerance to high gradient operation.

Fiber-Type Random Laser Based on a Cylindrical Waveguide with a Disordered Cladding Layer.

PubMed

Zhang, Wei Li; Zheng, Meng Ya; Ma, Rui; Gong, Chao Yang; Yang, Zhao Ji; Peng, Gang Ding; Rao, Yun Jiang

2016-05-25

This letter reports a fiber-type random laser (RL) which is made from a capillary coated with a disordered layer at its internal surface and filled with a gain (laser dye) solution in the core region. This fiber-type optical structure, with the disordered layer providing randomly scattered light into the gain region and the cylindrical waveguide providing confinement of light, assists the formation of random lasing modes and enables a flexible and efficient way of making random lasers. We found that the RL is sensitive to laser dye concentration in the core region and there exists a fine exponential relationship between the lasing intensity and particle concentration in the gain solution. The proposed structure could be a fine platform of realizing random lasing and random lasing based sensing.

Lennard-Jones fluids in two-dimensional nano-pores. Multi-phase coexistence and fluid structure

NASA Astrophysics Data System (ADS)

Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

2014-03-01

We present a number of fundamental findings on the wetting behaviour of nano-pores. A popular model for fluid confinement is a one-dimensional (1D) slit pore formed by two parallel planar walls and it exhibits capillary condensation (CC): a first-order phase transition from vapour to capillary-liquid (Kelvin shift). Capping such a pore at one end by a third orthogonal wall forms a prototypical two-dimensional (2D) pore. We show that 2D pores possess a wetting temperature such that below this temperature CC remains of first order, above it becomes a continuous phase transition manifested by a slab of capillary-liquid filling the pore from the capping wall. Continuous CC exhibits hysteresis and can be preceded by a first-order capillary prewetting transition. Additionally, liquid drops can form in the corners of the 2D pore (remnant of 2D wedge prewetting). The three fluid phases, vapour, capillary-liquid slab and corner drops, can coexist at the pore triple point. Our model is based on the statistical mechanics of fluids in the density functional formulation. The fluid-fluid and fluid-substrate interactions are dispersive. We analyze in detail the microscopic fluid structure, isotherms and full phase diagrams. Our findings also suggest novel ways to control wetting of nano-pores. We are grateful to the European Research Council via Advanced Grant No. 247031 for support.

NASA Tech Briefs, June 2003

NASA Technical Reports Server (NTRS)

2003-01-01

Topics covered include: Nulling Infrared Radiometer for Measuring Temperature; The Ames Power Monitoring System; Hot Films on Ceramic Substrates for Measuring Skin Friction; Probe Without Moving Parts Measures Flow Angle; Detecting Conductive Liquid Leaking from Nonconductive Pipe; Adaptive Suppression of Noise in Voice Communications; High-Performance Solid-State W-Band Power Amplifiers; Microbatteries for Combinatorial Studies of Conventional Lithium-Ion Batteries; Correcting for Beam Aberrations in a Beam-Waveguide Antenna; Advanced Rainbow Solar Photovoltaic Arrays; Metal Side Reflectors for Trapping Light in QWIPs; Software for Collaborative Engineering of Launch Rockets; Software Assists in Extensive Environmental Auditing; Software Supports Distributed Operations via the Internet; Software Estimates Costs of Testing Rocket Engines; yourSky: Custom Sky-Image Mosaics via the Internet; Software for Managing Inventory of Flight Hardware; Lower-Conductivity Thermal-Barrier Coatings; Process for Smoothing an Si Substrate after Etching of SiO2; Flexible Composite-Material Pressure Vessel; Treatment to Destroy Chlorohydrocarbon Liquids in the Ground; Noncircular Cross Sections Could Enhance Mixing in Sprays; Small, Untethered, Mobile Roots for Inspecting Gas Pipes; Paint-Overspray Catcher; Preparation of Regular Specimens for Atom Probes; Inverse Tomo-Lithography for Making Microscopic 3D Parts; Predicting and Preventing Incipient Flameout in Combustors; MEMS-Based Piezoelectric/Electrostatic Inchworm Actuator; Metallized Capillaries as Probes for Raman Spectroscopy; Adaptation of Mesoscale Weather Models to Local Forecasting; Aerodynamic Design using Neural Networks; Combining Multiple Gyroscope Outputs for Increased Accuracy; and Improved Collision-Detection Method for Robotic Manipulator.

Effect of Foam on Liquid Phase Mobility in Porous Media

NASA Astrophysics Data System (ADS)

Eftekhari, A. A.; Farajzadeh, R.

2017-03-01

We investigate the validity of the assumption that foam in porous media reduces the mobility of gas phase only and does not impact the liquid-phase mobility. The foam is generated by simultaneous injection of nitrogen gas and a surfactant solution into sandstone cores and its strength is varied by changing surfactant type and concentration. We find, indeed, that the effect of foam on liquid-phase mobility is not pronounced and can be ignored. Our new experimental results and analyses resolve apparent discrepancies in the literature. Previously, some researchers erroneously applied relative permeability relationships measured at small to moderate capillary numbers to foam floods at large capillary number. Our results indicate that the water relative permeability in the absence of surfactant should be measured with the capillary pressure ranging up to values reached during the foam floods. This requires conducting a steady-state gas/water core flood with capillary numbers similar to that of foam floods or measuring the water relative-permeability curve using a centrifuge.

Capillary forces exerted by liquid drops caught between crossed cylinders. A 3-D meniscus problem with free contact line

NASA Technical Reports Server (NTRS)

Patzek, T. W.; Scriven, L. E.

1982-01-01

The Young-Laplace equation is solved for three-dimensional menisci between crossed cylinders, with either the contact line fixed or the contact angle prescribed, by means of the Galerkin/finite element method. Shapes are computed, and with them the practically important quantities: drop volume, wetted area, capillary pressure force, surface tension force, and the total force exerted by the drop on each cylinder. The results show that total capillary force between cylinders increases with decreasing contact angle, i.e. with better wetting. Capillary force is also increases with decreasing drop volume, approaching an asymptotic limit. However, the wetted area on each cylinder decreases with decreasing drop volume, which raises the question of the optimum drop volume to strive for, when permanent bonding is sought from solidified liquid. For then the strength of the bond is likely to depend upon the area of contact, which is the wetted area when the bonding agent was introduced in liquid form.

Effect of Foam on Liquid Phase Mobility in Porous Media

PubMed Central

Eftekhari, A. A.; Farajzadeh, R.

2017-01-01

We investigate the validity of the assumption that foam in porous media reduces the mobility of gas phase only and does not impact the liquid-phase mobility. The foam is generated by simultaneous injection of nitrogen gas and a surfactant solution into sandstone cores and its strength is varied by changing surfactant type and concentration. We find, indeed, that the effect of foam on liquid-phase mobility is not pronounced and can be ignored. Our new experimental results and analyses resolve apparent discrepancies in the literature. Previously, some researchers erroneously applied relative permeability relationships measured at small to moderate capillary numbers to foam floods at large capillary number. Our results indicate that the water relative permeability in the absence of surfactant should be measured with the capillary pressure ranging up to values reached during the foam floods. This requires conducting a steady-state gas/water core flood with capillary numbers similar to that of foam floods or measuring the water relative-permeability curve using a centrifuge. PMID:28262795

Gravimetric capillary method for kinematic viscosity measurements

NASA Technical Reports Server (NTRS)

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

1992-01-01

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

Respiratory fluid mechanics

PubMed Central

Grotberg, James B.

2011-01-01

This article covers several aspects of respiratory fluid mechanics that have been actively investigated by our group over the years. For the most part, the topics involve two-phase flows in the respiratory system with applications to normal and diseased lungs, as well as therapeutic interventions. Specifically, the topics include liquid plug flow in airways and at airway bifurcations as it relates to surfactant, drug, gene, or stem cell delivery into the lung; liquid plug rupture and its damaging effects on underlying airway epithelial cells as well as a source of crackling sounds in the lung; airway closure from “capillary-elastic instabilities,” as well as nonlinear stabilization from oscillatory core flow which we call the “oscillating butter knife;” liquid film, and surfactant dynamics in an oscillating alveolus and the steady streaming, and surfactant spreading on thin viscous films including our discovery of the Grotberg–Borgas–Gaver shock. PMID:21403768

Cell dispensing in low-volume range with the immediate drop-on-demand technology (I-DOT).

PubMed

Schober, Lena; Büttner, Evy; Laske, Christopher; Traube, Andrea; Brode, Tobias; Traube, Andreas Florian; Bauernhansl, Thomas

2015-04-01

Handling and dosing of cells comprise the most critical step in the microfabrication of cell-based assay systems for screening and toxicity testing. Therefore, the immediate drop-on-demand technology (I-DOT) was developed to provide a flexible noncontact liquid handling system enabling dispensing of cells and liquid without the risk of cross-contamination down to a precise volume in the nanoliter range. Liquid is dispensed from a source plate within nozzles at the bottom by a short compressed air pulse that is given through a quick release valve into the well, thus exceeding the capillary pressure in the nozzle. Droplets of a defined volume can be spotted directly onto microplates or other cell culture devices. We present a study on the performance and biological impact of this technology by applying the cell line MCF-7, human fibroblasts, and human mesenchymal stem cells (hMSCs). For all cell types tested, viability after dispensing is comparable to the control and exhibits similar proliferation rates in the absence of apoptotic cells, and the differentiation potential of hMSCs is not impaired. The immediate drop-on-demand technology enables accurate cell dosage and offers promising potential for single-cell applications. © 2014 Society for Laboratory Automation and Screening.

Tapered optical fiber waveguide coupling to whispering gallery modes of liquid crystal microdroplet for thermal sensing application.

PubMed

Wang, Yan; Li, Hanyang; Zhao, Liyuan; Liu, Yongjun; Liu, Shuangqiang; Yang, Jun

2017-01-23

We demonstrate efficient coupling to the optical whispering gallery modes (WGMs) of nematic liquid crystal (NLC) microdroplets immersed in an immiscible aqueous environment. An individual NLC microdroplet, confined at the tip of a microcapillary, was coupled via a tapered optical fiber waveguide positioned correctly within its vicinity. Critical coupling of the taper-microdroplet system was facilitated by adjusting the gap between the taper and the microdroplet to change the overlap of the evanescent electromagnetic fields; efficient and controlled power transfer from the taper waveguide to the NLC microdroplet is indeed possible via the proposed technique. We also found that NLC microdroplets can function as highly sensitive thermal sensors: A maximum temperature sensitivity of 267.6 pm/°C and resolution of 7.5 × 10^-2 °C were achieved in a 78-μm-diameter NLC microdroplet.

Efficient channel-waveguide laser in Nd:GGG at 1.062 μm wavelength

NASA Astrophysics Data System (ADS)

Gerhardt, R.; Kleine-Börger, J.; Beilschmidt, L.; Frommeyer, M.; Dötsch, H.; Gather, B.

1999-08-01

Channel waveguide lasers in crystals of neodymium-doped gadolinium-gallium-garnet are realized. They are based on single-mode rib waveguides prepared by liquid phase epitaxy. By this growth technique the incorporation of certain impurities, which may cause severe quenching, is inevitable. The dominant quenching process could be identified and eliminated. Channel waveguides with extremely low losses, down to 0.25 dB/cm for both TE and TM modes, are fabricated by ion-beam etching. As a result, low thresholds of 5 mW and high slope efficiencies of 48% at the laser wavelength of 1.062 μm could be achieved when pumping at a wavelength of 807 nm.

Chemical microreactor and method thereof

DOEpatents

Morse, Jeffrey D [Martinez, CA; Jankowski, Alan [Livermore, CA

2011-08-09

A method for forming a chemical microreactor includes forming at least one capillary microchannel in a substrate having at least one inlet and at least one outlet, integrating at least one heater into the chemical microreactor, interfacing the capillary microchannel with a liquid chemical reservoir at the inlet of the capillary microchannel, and interfacing the capillary microchannel with a porous membrane near the outlet of the capillary microchannel, the porous membrane being positioned beyond the outlet of the capillary microchannel, wherein the porous membrane has at least one catalyst material imbedded therein.

Physicochemical application of capillary chromatography

NASA Astrophysics Data System (ADS)

Vasil'ev, A. V.; Aleksandrov, E. N.

1992-04-01

The application of capillary gas chromatography in the determination of the free energy, enthalpy, and entropy of sorption, the saturated vapour pressure and activity coefficients, the assessment of the lipophilicity of volatile compounds, and the study of the properties of polymers and liquid crystals is described. The use of reaction cappillary chromatography in kinetic studies of conformational conversions, thermal degradation, and photochemical reactions is examined. Studies on the use of capillary columns for determination of the second virial coefficients and viscosity of gases and the diffusion coefficients in gases, liquids, supercritical fluids, and polymers are analysed. The bibliography includes 114 references.

Pulsed electrothermal thruster

NASA Technical Reports Server (NTRS)

Burton, Rodney L. (Inventor); Goldstein, Yeshayahu S. A. (Inventor); Tidman, Derek A. (Inventor); Winsor, Niels K. (Inventor)

1989-01-01

A plasma electrothermal thruster includes a capillary passage in which a plasma discharge is formed and directed out of an open end of the passage into a supersonic nozzle. Liquid supplied to the capillary passage becomes partially atomized to cool a confining surface of the passage. The plasma discharge is formed as the atomized liquid flows out of the open end into a supersonic equilibrium nozzle. The discharge can have a duration greater than the two way travel time of acoustic energy in the capillary to cause the plasma to flow continuously through the nozzle during the time of the discharge pulse.

Properties of pendular liquid bridges determined on Delaunay's roulettes

NASA Astrophysics Data System (ADS)

Mielniczuk, Boleslaw; Millet, Olivier; Gagneux, Gérard; El Youssoufi, Moulay Said

2017-06-01

This work addresses the study of capillary bridge properties between two grains, with use of recent analytical model, based on solutions of Young-Laplace equation from an inverse problem. A simple explicit criterion allows to classify the profile of capillary bridge as a surface of revolution with constant mean curvature (Delaunay roulette) using its measured geometrical parameters (gorge radius, contact angle, half-filling angle). Necessary data are obtained from experimental tests, realized on liquid bridges between two equal spherical grains. Sequences of images are recorded at several (fixed) volumes of liquid and different separations distances between the spheres (from contact to rupture), in laboratory and in micro-gravity conditions. For each configuration, an exact parametric representation of the meridian is revealed. Mean bridge curvature, internal pressure and intergranular capillary force are also determined.

Sheath-flow electrochemical detection of amino acids with a copper wire electrode in capillary electrophoresis.

PubMed

Inoue, Junji; Kaneta, Takashi; Imasaka, Totaro

2012-09-01

Here, we report the detection of native amino acids using a sheath-flow electrochemical detector with a working electrode made of copper wire. A separation capillary that was inserted into a platinum tube in the detector acted as a grounded electrode for electrophoresis and as a flow channel for sheath liquid. Sheath liquid flowed outside the capillary to support the transport of the separated analytes to the working electrode for electrochemical detection. The copper wire electrode was aligned at the outlet of the capillary in a wall-jet configuration. Amino acids injected into the capillary were separated following elution from the end of the capillary and detection by the copper electrode. Three kinds of copper electrodes with different diameters-50, 125, and 300 μm-were examined to investigate the effect of the electrode diameter on sensitivity. The peak widths of the analytes were independent of the diameter of the working electrode, while the 300-μm electrode led to a decrease in the signal-to-noise ratio compared with the 50- and 125-μm electrodes, which showed no significant difference. The flow rate of the sheath liquid was also varied to optimize the detection conditions. The limits of detection for amino acids ranged from 4.4 to 27 μM under optimal conditions. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Actuation of flexoelectric membranes in viscoelastic fluids with applications to outer hair cells

PubMed Central

Herrera-Valencia, E. E.; Rey, Alejandro D.

2014-01-01

Liquid crystal flexoelectric actuation uses an imposed electric field to create membrane bending, and it is used by the outer hair cells (OHCs) located in the inner ear, whose role is to amplify sound through generation of mechanical power. Oscillations in the OHC membranes create periodic viscoelastic flows in the contacting fluid media. A key objective of this work on flexoelectric actuation relevant to OHCs is to find the relations and impact of the electromechanical properties of the membrane, the rheological properties of the viscoelastic media, and the frequency response of the generated mechanical power output. The model developed and used in this work is based on the integration of: (i) the flexoelectric membrane shape equation applied to a circular membrane attached to the inner surface of a circular capillary and (ii) the coupled capillary flow of contacting viscoelastic phases, such that the membrane flexoelectric oscillations drive periodic viscoelastic capillary flows, as in OHCs. By applying the Fourier transform formalism to the governing equation, analytical expressions for the transfer function associated with the curvature and electrical field and for the power dissipation of elastic storage energy were found. PMID:25332388

Ultrafast preparation of a polyhedral oligomeric silsesquioxane-based ionic liquid hybrid monolith via photoinitiated polymerization, and its application to capillary electrochromatography of aromatic compounds.

PubMed

Zhang, Bingyu; Lei, Xiaoyun; Deng, Lijun; Li, Minsheng; Yao, Sicong; Wu, Xiaoping

2018-06-06

An ionic liquid hybrid monolithic capillary column was prepared within 7 min via photoinitiated free-radical polymerization of an ionic liquid monomer (1-butyl-3-vinylimidazolium-bis[(trifluoromethyl)sulfonyl]imide); VBIMNTF 2 ) and a methacryl substituted polyhedral oligomeric silsesquioxane (POSS-MA) acting as a cross-linker. The effects of composition of prepolymerization solution and initiation time on the porous structure and electroosmotic flow (EOF) of monolithic column were investigated. The hybrid monolith was characterized by scanning electron microscopy and FTIR. Owing to the introduction of a rigid nanosized POSS silica core and ionic liquids with multiple interaction sites, the monolithic column has a well-defined 3D skeleton morphology, good mechanical stability, and a stable anodic electroosmotic flow. The hybrid monolithic stationary phase was applied to the capillary electrochromatographic separation of various alkylbenzenes, phenols, anilines and polycyclic aromatic hydrocarbons (PAHs). The column efficiency is highest (98,000 plates/m) in case of alkylbenzenes. Mixed-mode retention mechanisms including hydrophobic interactions, π-π stacking, electrostatic interaction and electrophoretic mobility can be observed. This indicates the potential of this material in terms of efficient separation of analytes of different structural type. Graphical Abstract Preparation of a mixed-mode ionic liquid hybrid monolithic column via photoinitiated polymerization of methacryl substituted polyhedral oligomeric silsesquioxane (POSS-MA) and 1-butyl-3-vinylimidazolium-bis[(trifluoromethyl)sulfonyl]imide (VBIMNTF 2 ) ionic liquid for use in capillary electrochromatography.

Microbial growth and transport in saturated and unsaturated porous media

NASA Astrophysics Data System (ADS)

Hron, Pavel; Jost, Daniel; Bastian, Peter; Ippisch, Olaf

2014-05-01

There is a considerable ongoing effort aimed at understanding the behavior of microorganisms in porous media. Microbial activity is of significant interest in various environmental applications such as in situ bioremediation, protection of drinking water supplies and for subsurface geochemistry in general. The main limiting factors for bacterial growth are the availability of electron acceptors, nutrients and bio-available water. The capillary fringe, defined - in a wider sense than usual - as the region of the subsurface above the groundwater table, but still dominated by capillary rise, is a region where all these factors are abundantly available. It is thus a region where high microbial activity is to be expected. In a research unit 'Dynamic Capillary Fringes - A Multidisciplinary Approach (DyCap)' founded by the German Research Foundation (DFG), the growth of microorganisms in the capillary fringe was studied experimentally and with numerical simulations. Processes like component transport and diffusion, exchange between the liquid phase and the gas phase, microbial growth and cell attachment and detachment were incorporated into a numerical simulator. The growth of the facultative anaerobic Escherichia coli as a function of nutrient availability and oxygen concentration in the liquid phase is modeled with modified Monod-type models and modifications for the switch between aerobic and anaerobic growth. Laboratory batch experiments with aqueous solutions of bacteria have been carried out under various combinations of oxygen concentrations in the gas phase and added amounts of dissolved organic carbon to determine the growth model parameters by solution of a parameter estimation problem. For the transport of bacteria the adhesion to phase boundaries is also very important. As microorganisms are transported through porous media, they are removed from the pore fluid by physicochemical filtration (attachment to sediment grain surfaces) or are adhering to gas-water interface. The cell attachment and detachment model was based on flow-through experiments and the parameters were obtained by fitting the model to measured bacteria breakthrough curves. Experiments on bacterial growth in porous media with and without groundwater flow were performed in Hele-Shaw cells filled with quartz sands. The cell density was determined by the fluorescence of a special protein produced by the genetically modified strain of E. coli. The simulation results are compared to experimental data and different modeling approaches are discussed.

Liquid-metal plasma-facing component research on the National Spherical Torus Experiment

NASA Astrophysics Data System (ADS)

Jaworski, M. A.; Khodak, A.; Kaita, R.

2013-12-01

Liquid metal plasma-facing components (PFCs) have been proposed as a means of solving several problems facing the creation of economically viable fusion power reactors. Liquid metals face critical issues in three key areas: free-surface stability, material migration and demonstration of integrated scenarios. To date, few demonstrations exist of this approach in a diverted tokamak and we here provide an overview of such work on the National Spherical Torus Experiment (NSTX). The liquid lithium divertor (LLD) was installed and operated for the 2010 run campaign using evaporated coatings as the filling method. Despite a nominal liquid level exceeding the capillary structure and peak current densities into the PFCs exceeding 100 kA m-2, no macroscopic ejection events were observed. The stability can be understood from a Rayleigh-Taylor instability analysis. Capillary restraint and thermal-hydraulic considerations lead to a proposed liquid-metal PFCs scheme of actively-supplied, capillary-restrained systems. Even with state-of-the-art cooling techniques, design studies indicate that the surface temperature with divertor-relevant heat fluxes will still reach temperatures above 700 °C. At this point, one would expect significant vapor production from a liquid leading to a continuously vapor-shielded regime. Such high-temperature liquid lithium PFCs may be possible on the basis of momentum-balance arguments.

Solvent-resistant sol-gel polydimethyldiphenylsiloxane coating for on-line hyphenation of capillary microextraction with high-performance liquid chromatography.

PubMed

Segro, Scott S; Malik, Abdul

2008-09-26

A sol-gel polydimethyldiphenylsiloxane (PDMDPS) coating was developed for capillary microextraction on-line hyphenated with high-performance liquid chromatography (HPLC). This coating was created using methyltrimethoxysilane (MTMS) as the sol-gel precursor and di-hydroxy-terminated PDMDPS as the sol-gel active polymer. The methyl and phenyl groups on the sol-gel active polymer and the methyl groups on the sol-gel precursor ultimately turned into pendant groups providing the ability to extract non-polar analytes. A 40-cm segment of 0.25 mm I.D. fused silica capillary containing the sol-gel PDMDPS coating was installed as an external sampling loop in an HPLC injection port. Aqueous samples containing polycyclic aromatic hydrocarbons (PAHs), aromatic compounds, ketones, and aldehydes were passed through this capillary wherein the analytes were extracted by the sol-gel coating. The extracted analytes were then transferred to the HPLC column using isocratic or gradient elution with an acetonitrile/water mobile phase. This capillary demonstrated excellent extraction capability for non-polar (e.g., polycyclic aromatic hydrocarbons and aromatic compounds) as well as moderately polar compounds, such as aromatic amines, ketones, and aldehydes. The test results indicate that PDMDPS can be successfully immobilized into a sol-gel network and that the resulting solvent-resistant sol-gel organic-inorganic hybrid coating can be effectively used for on-line hyphenation of capillary microextraction with high-performance liquid chromatography. The test results also indicate that the sol-gel PDMDPS coated capillary is resistant to high-temperature solvents, making it suitable for applications in high-temperature HPLC. To the best of our knowledge, this is the first report on the creation of a silica-based sol-gel PDMDPS coating used in capillary microextraction on-line hyphenated to HPLC.

Tube Radial Distribution Flow Separation in a Microchannel Using an Ionic Liquid Aqueous Two-Phase System Based on Phase Separation Multi-Phase Flow.

PubMed

Nagatani, Kosuke; Shihata, Yoshinori; Matsushita, Takahiro; Tsukagoshi, Kazuhiko

2016-01-01

Ionic liquid aqueous two-phase systems were delivered into a capillary tube to achieve tube radial distribution flow (TRDF) or annular flow in a microspace. The phase diagram, viscosity of the phases, and TRDF image of the 1-butyl-3-methylimidazolium chloride and NaOH system were examined. The TRDF was formed with inner ionic liquid-rich and outer ionic liquid-poor phases in the capillary tube. The phase configuration was explained using the viscous dissipation principle. We also examined the distribution of rhodamine B in a three-branched microchannel on a microchip with ionic liquid aqueous two-phase systems for the first time.

Salting-out assisted liquid-liquid extraction combined with capillary HPLC for the determination of sulfonylurea herbicides in environmental water and banana juice samples.

PubMed

Gure, Abera; Lara, Francisco J; Moreno-González, David; Megersa, Negussie; del Olmo-Iruela, Monsalud; García-Campaña, Ana M

2014-09-01

A salting-out assisted liquid-liquid extraction (SALLE) combined with capillary high performance liquid chromatography with diode array detector (capillary HPLC-DAD) was proposed for extraction and determination of residues of nine sulfonylurea herbicides (SUHs) in environmental water and banana juice samples. Various parameters affecting the extraction process such as the type and volume of the organic solvent, sample volume, type and amount of salt, pH of the sample and vortex time were optimized. Under optimum conditions, matrix matched calibration curves were established using river water and banana juice samples. Good linear relationships as well as low limits of detection, LODs (0.4-1.3 and 3-13 µg/L) and quantification, LOQs (1.3-4.3 and 10-43 µg/L) were obtained in water and banana juice samples, respectively. The precision (intra- and inter-day) of the peak areas expressed as relative standard deviations (%, RSD), at two concentration levels were below 10 % in both matrices. Recoveries obtained from spiked environmental waters (river water and groundwater) and banana juice samples, at two concentration levels, ranged from 72 to 115%. The results of the analysis revealed that the proposed SALLE-capillary HPLC method is simple, rapid, cheap and environmentally friendly, being successfully applicable for the determination of SUH residues in waters and banana juices. Copyright © 2014 Elsevier B.V. All rights reserved.

Device and method for automated separation of a sample of whole blood into aliquots

DOEpatents

Burtis, Carl A.; Johnson, Wayne F.

1989-01-01

A device and a method for automated processing and separation of an unmeasured sample of whole blood into multiple aliquots of plasma. Capillaries are radially oriented on a rotor, with the rotor defining a sample chamber, transfer channels, overflow chamber, overflow channel, vent channel, cell chambers, and processing chambers. A sample of whole blood is placed in the sample chamber, and when the rotor is rotated, the blood moves outward through the transfer channels to the processing chambers where the blood is centrifugally separated into a solid cellular component and a liquid plasma component. When the rotor speed is decreased, the plasma component backfills the capillaries resulting in uniform aliquots of plasma which may be used for subsequent analytical procedures.

Refractive waveguide non-mechanical beam steering (NMBS) in the MWIR

NASA Astrophysics Data System (ADS)

Myers, Jason D.; Frantz, Jesse A.; Spillmann, Christopher M.; Bekele, Robel Y.; Kolacz, Jakub; Gotjen, Henry; Naciri, Jawad; Shaw, Brandon; Sanghera, Jas S.

2018-02-01

Beam steering is a crucial technology for a number of applications, including chemical sensing/mapping and light detection and ranging (LIDAR). Traditional beam steering approaches rely on mechanical movement, such as the realignment of mirrors in gimbal mounts. The mechanical approach to steering has several drawbacks, including large size, weight and power usage (SWAP), and frequent mechanical failures. Recently, alternative non-mechanical approaches have been proposed and developed, but these technologies do not meet the demanding requirements for many beam steering applications. Here, we highlight the development efforts into a particular non-mechanical beam steering (NMBS) approach, refractive waveguides, for application in the MWIR. These waveguides are based on an Ulrich-coupled slab waveguide with a liquid crystal (LC) top cladding; by selectively applying an electric field across the liquid crystal through a prismatic electrode, steering is achieved by creating refraction at prismatic interfaces as light propagates through the device. For applications in the MWIR, we describe a versatile waveguide architecture based on chalcogenide glasses that have a wide range of refractive indices, transmission windows, and dispersion properties. We have further developed robust shadow-masking methods to taper the subcladding layers in the coupling region. We have demonstrated devices with >10° of steering in the MWIR and a number of advantageous properties for beam steering applications, including low-power operation, compact size, and fast point-to-point steering.

A hybrid waveguide cell for the dielectric properties of reservoir rocks

NASA Astrophysics Data System (ADS)

Siggins, A. F.; Gunning, J.; Josh, M.

2011-02-01

A hybrid waveguide cell is described for broad-band measurements of the dielectric properties of hydrocarbon reservoir rocks. The cell is designed to operate in the radio frequency range of 1 MHz to 1 GHz. The waveguide consists of 50 Ω coaxial lines feeding into a central cylindrical section which contains the sample under test. The central portion of the waveguide acts as a circular waveguide and can accept solid core plugs of 38 mm diameter and lengths from 2 to 150 mm. The central section can also be used as a conventional coaxial waveguide when a central electrode with spring-loaded end collets is installed. In the latter mode the test samples are required to be in the form of hollow cylinders. An additional feature of the cell is that the central section is designed to telescope over a limited range of 1-2 mm with the application of an axial load. Effective pressures up to 35 MPa can be applied to the sample under the condition of uniaxial strain. The theoretical basis of the hybrid waveguide cell is discussed together with calibration results. Two reservoir rocks, a Donnybrook sandstone and a kaolin rich clay, are then tested in the cell, both as hollow cylinders in coaxial mode and in the form of solid core plugs. The complex dielectric properties of the two materials over the bandwidth of 1 MHz to 1 GHz are compared with the results of the two testing methods.

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.

G-index: A new metric to describe dynamic refractive index effects in HPLC absorbance detection.

PubMed

Kraiczek, Karsten G; Rozing, Gerard P; Zengerle, Roland

2018-09-01

High performance liquid chromatography (HPLC) with a solvent gradient and absorbance detection is one of the most widely used methods in analytical chemistry. The observed absorbance baseline is affected by the changes in the refractive index (RI) of the mobile phase. Near the limited of detection, this complicates peak quantitation. The general aspects of these RI-induced apparent absorbance effects are discussed. Two different detectors with fundamentally different optics and flow cell concepts, a variable-wavelength detector equipped with a conventional flow cell and a diode-array detector equipped with a liquid core waveguide flow cell, are compared with respect to their RI behavior. A simple method to separate static - partly unavoidable - RI effects from dynamic RI effects is presented. It is shown that the dynamic RI behavior of an absorbance detector can be well described using a single, relatively easy-to-determine metric called the G-index. The G-index is typically in the order of a few seconds and its sign depends on the optical flow cell concept. Copyright © 2018 Elsevier B.V. All rights reserved.

Expanding Taylor bubble under constant heat flux

NASA Astrophysics Data System (ADS)

Voirand, Antoine; Benselama, Adel M.; Ayel, Vincent; Bertin, Yves

2016-09-01

Modelization of non-isothermal bubbles expanding in a capillary, as a contribution to the understanding of the physical phenomena taking place in Pulsating Heat Pipes (PHPs), is the scope of this paper. The liquid film problem is simplified and solved, while the thermal problem takes into account a constant heat flux density applied at the capillary tube wall, exchanging with the liquid film surrounding the bubble and also with the capillary tube outside medium. The liquid slug dynamics is solved using the Lucas-Washburn equation. Mass and energy balance on the vapor phase allow governing equations of bubble expansion to be written. The liquid and vapor phases are coupled only through the saturation temperature associated with the vapor pressure, assumed to be uniform throughout the bubble. Results show an over-heating of the vapor phase, although the particular thermal boundary condition used here always ensures an evaporative mass flux at the liquid-vapor interface. Global heat exchange is also investigated, showing a strong decreasing of the PHP performance to convey heat by phase change means for large meniscus velocities.

Foam on troubled water: Capillary induced finite-time arrest of sloshing waves

NASA Astrophysics Data System (ADS)

Viola, Francesco; Brun, P.-T.; Dollet, Benjamin; Gallaire, François

2016-09-01

Interfacial forces exceed gravitational forces on a scale small relative to the capillary length—two millimeters in the case of an air-water interface—and therefore dominate the physics of sub-millimetric systems. They are of paramount importance for various biological taxa and engineering processes where the motion of a liquid meniscus induces a viscous frictional force that exhibits a sublinear dependence in the meniscus velocity, i.e., a power law with an exponent smaller than one. Interested in the fundamental implications of this dependence, we use a liquid-foam sloshing system as a prototype to exacerbate the effect of sublinear friction on the macroscopic mechanics of multi-phase flows. In contrast to classical theory, we uncover the existence of a finite-time singularity in our system yielding the arrest of the fluid's oscillations. We propose a minimal theoretical framework to capture this effect, thereby amending the paradigmatic damped harmonic oscillator model. Our results suggest that, although often not considered at the macroscale, sublinear capillary forces govern the friction at liquid-solid and liquid-liquid interfaces.

Directional, passive liquid transport: the Texas horned lizard as a model for a biomimetic ‘liquid diode’

PubMed Central

Comanns, Philipp; Buchberger, Gerda; Buchsbaum, Andreas; Baumgartner, Richard; Kogler, Alexander; Bauer, Siegfried; Baumgartner, Werner

2015-01-01

Moisture-harvesting lizards such as the Texas horned lizard (Iguanidae: Phrynosoma cornutum) live in arid regions. Special skin adaptations enable them to access water sources such as moist sand and dew: their skin is capable of collecting and transporting water directionally by means of a capillary system between the scales. This fluid transport is passive, i.e. requires no external energy, and directs water preferentially towards the lizard's snout. We show that this phenomenon is based on geometric principles, namely on a periodic pattern of interconnected half-open capillary channels that narrow and widen. Following a biomimetic approach, we used these principles to develop a technical prototype design. Building upon the Young–Laplace equation, we derived a theoretical model for the local behaviour of the liquid in such capillaries. We present a global model for the penetration velocity validated by experimental data. Artificial surfaces designed in accordance with this model prevent liquid flow in one direction while sustaining it in the other. Such passive directional liquid transport could lead to process improvements and reduction of resources in many technical applications. PMID:26202685

Liquid crystal waveguides: new devices enabled by >1000 waves of optical phase control

NASA Astrophysics Data System (ADS)

Davis, Scott R.; Farca, George; Rommel, Scott D.; Johnson, Seth; Anderson, Michael H.

2010-02-01

A new electro-optic waveguide platform, which provides unprecedented voltage control over optical phase delays (> 2mm), with very low loss (< 0.5 dB/cm) and rapid response time (sub millisecond), will be presented. This technology, developed by Vescent Photonics, is based upon a unique liquid-crystal waveguide geometry, which exploits the tremendous electro-optic response of liquid crystals while circumventing their historic limitations. The waveguide geometry provides nematic relaxation speeds in the 10's of microseconds and LC scattering losses that are reduced by orders of magnitude from bulk transmissive LC optics. The exceedingly large optical phase delays accessible with this technology enable the design and construction of a new class of previously unrealizable photonic devices. Examples include: 2-D analog non-mechanical beamsteerers, chip-scale widely tunable lasers, chip-scale Fourier transform spectrometer (< 5 nm resolution demonstrated), widely tunable micro-ring resonators, tunable lenses, ultra-low power (< 5 microWatts) optical switches, true optical time delay devices for phased array antennas, and many more. All of these devices may benefit from established manufacturing technologies and ultimately may be as inexpensive as a calculator display. Furthermore, this new integrated photonic architecture has applications in a wide array of commercial and defense markets including: remote sensing, micro-LADAR, OCT, FSO, laser illumination, phased array radar, etc. Performance attributes of several example devices and application data will be presented. In particular, we will present a non-mechanical beamsteerer that steers light in both the horizontal and vertical dimensions.

INTEGRATED AND FIBER OPTICS: Unidirectional coupling of radiation out of a composite dielectric waveguide

NASA Astrophysics Data System (ADS)

Avrutskiĭ, I. A.; Sychugov, V. A.; Tishchenko, A. V.; Svakhin, A. S.

1989-02-01

An analysis is made of the emission of light from a composite system representing a thin film on the surface of a corrugated diffused waveguide. Expressions are obtained for the radiative light losses in this waveguide. There is no emission of light into the substrate for certain relationships between the amplitudes and phases of the corrugations at the interfaces between the film and the adjoining medium and between the film and the waveguide. Numerical estimates of the losses are obtained for a case of practical importance, which is a corrugated diffused waveguide in glass with a film of Nb2O5 on the surface. A report is given of an experiment in which a grating was formed for coupling radiation out of a composite Cs+-diffused waveguide coated by a film of Nb2O5, which was capable of preferential (80%) emission of radiation into air, and in the presence of an immersion liquid ensured practically unidirectional coupling out of radiation into air.

Thermodynamic Investigation of the Effect of Interface Curvature on the Solid-Liquid Equilibrium and Eutectic Point of Binary Mixtures.

PubMed

Liu, Fanghui; Zargarzadeh, Leila; Chung, Hyun-Joong; Elliott, Janet A W

2017-10-12

Thermodynamic phase behavior is affected by curved interfaces in micro- and nanoscale systems. For example, capillary freezing point depression is associated with the pressure difference between the solid and liquid phases caused by interface curvature. In this study, the thermal, mechanical, and chemical equilibrium conditions are derived for binary solid-liquid equilibrium with a curved solid-liquid interface due to confinement in a capillary. This derivation shows the equivalence of the most general forms of the Gibbs-Thomson and Ostwald-Freundlich equations. As an example, the effect of curvature on solid-liquid equilibrium is explained quantitatively for the water/glycerol system. Considering the effect of a curved solid-liquid interface, a complete solid-liquid phase diagram is developed over a range of concentrations for the water/glycerol system (including the freezing of pure water or precipitation of pure glycerol depending on the concentration of the solution). This phase diagram is compared with the traditional phase diagram in which the assumption of a flat solid-liquid interface is made. We show the extent to which nanoscale interface curvature can affect the composition-dependent freezing and precipitating processes, as well as the change in the eutectic point temperature and concentration with interface curvature. Understanding the effect of curvature on solid-liquid equilibrium in nanoscale capillaries has applications in the food industry, soil science, cryobiology, nanoporous materials, and various nanoscience fields.

Multicomponent micropatterned sol-gel materials by capillary molding

NASA Astrophysics Data System (ADS)

Lochhead, Michael J.; Yager, Paul

1997-10-01

A physically and chemically benign method for patterning multiple sol-gel materials onto a single substrate is described. Structures are demonstrated for potential micro- optical chemical sensor, biosensor, and waveguiding applications. Fabrication is based on the micro molding in capillaries (MIMIC) approach. A novel mold design allows several sols to be cast simultaneously. Closely spaced, organically modified silica ridges containing fluorescent dyes are demonstrated. Ridges have cross sectional dimensions from one to 50 micrometers and are centimeters in length. Processing issues, particularly those related to mold filling, are discussed in detail. Because sol-gel MIMIC avoids the harsh physical and chemical environments normally associated with patterning, the approach allows full exploitation of sol- gel processing advantages, such as the ability to entrap sensitive organic dopant molecules in the sol-gel matrix.

The Propagation of a Liquid Bolus Through an Elastic Tube and Airway Reopening

NASA Technical Reports Server (NTRS)

Howell, Peter D.; Grotberg, James B.

1996-01-01

We use lubrication theory and matched asymptotic expansions to model the quasi-steady propagation of a liquid bridge through an elastic tube. In the limit of small capillary number, asymptotic expressions are found for the pressure drop across the bridge and the thickness of the liquid film left behind, as functions of the capillary number, the thickness of the liquid lining ahead of the bridge and the elastic characteristics of the tube wall. For a given precursor thickness, we find a critical propagation speed, and hence a critical imposed pressure drop, above which the bridge will eventually burst, and hence the tube will reopen.

Multi-leg heat pipe evaporator

NASA Technical Reports Server (NTRS)

Alario, J. P.; Haslett, R. A. (Inventor)

1986-01-01

A multileg heat pipe evaporator facilitates the use and application of a monogroove heat pipe by providing an evaporation section which is compact in area and structurally more compatible with certain heat exchangers or heat input apparatus. The evaporation section of a monogroove heat pipe is formed by a series of parallel legs having a liquid and a vapor channel and a communicating capillary slot therebetween. The liquid and vapor channels and interconnecting capillary slots of the evaporating section are connected to the condensing section of the heat pipe by a manifold connecting liquid and vapor channels of the parallel evaporation section legs with the corresponding liquid and vapor channels of the condensing section.

Stability limits of unsteady open capillary channel flow

NASA Astrophysics Data System (ADS)

Grah, Aleksander; Haake, Dennis; Rosendahl, Uwe; Klatte, J.?Rg; Dreyer, Michael E.

This paper is concerned with steady and unsteady flow rate limitations in open capillary channels under low-gravity conditions. Capillary channels are widely used in Space technology for liquid transportation and positioning, e.g. in fuel tanks and life support systems. The channel observed in this work consists of two parallel plates bounded by free liquid surfaces along the open sides. The capillary forces of the free surfaces prevent leaking of the liquid and gas ingestion into the flow.In the case of steady stable flow the capillary pressure balances the differential pressure between the liquid and the surrounding constant-pressure gas phase. Increasing the flow rate in small steps causes a decrease of the liquid pressure. A maximum steady flow rate is achieved when the flow rate exceeds a certain limit leading to a collapse of the free surfaces due to the choking effect. In the case of unsteady flow additional dynamic effects take place due to flow rate transition and liquid acceleration. The maximum flow rate is smaller than in the case of steady flow. On the other hand, the choking effect does not necessarily cause surface collapse and stable temporarily choked flow is possible under certain circumstances.To determine the limiting volumetric flow rate and stable flow dynamic properties, a new stability theory for both steady and unsteady flow is introduced. Subcritical and supercritical (choked) flow regimes are defined. Stability criteria are formulated for each flow type. The steady (subcritical) criterion corresponds to the speed index defined by the limiting longitudinal small-amplitude wave speed, similar to the Mach number. The unsteady (supercritical) criterion for choked flow is defined by a new characteristic number, the dynamic index. It is based on pressure balances and reaches unity at the stability limit.The unsteady model based on the Bernoulli equation and the mass balance equation is solved numerically for perfectly wetting incompressible liquids. The unsteady model and the stability theory are verified by comparison to results of a sounding rocket experiment (TEXUS 41) on capillary channel flows launched in December 2005 from ESRANGE in north Sweden. For a clear overview of subcritical, supercritical, and unstable flow, parametric studies and stability diagrams are shown and compared to experimental observations.

Infiltration of MHD liquid into a deformable porous material

NASA Astrophysics Data System (ADS)

Naseem, Anum; Mahmood, Asif; Siddique, J. I.; Zhao, Lifeng

2018-03-01

We analyze the capillary rise dynamics for magnetohydrodynamics (MHD) fluid flow through deformable porous material in the presence of gravity effects. The modeling is performed using mixture theory approach and mathematical manipulation yields a nonlinear free boundary problem. Due to the capillary rise action, the pressure gradient in the liquid generates a stress gradient that results in the deformation of porous substrate. The capillary rise process for MHD fluid slows down as compared to Newtonian fluid case. Numerical solutions are obtained using a method of lines approach. The graphical results are presented for important physical parameters, and comparison is presented with Newtonian fluid case.

Electrochemical attosyringe.

PubMed

Laforge, François O; Carpino, James; Rotenberg, Susan A; Mirkin, Michael V

2007-07-17

The ability to manipulate ultrasmall volumes of liquids is essential in such diverse fields as cell biology, microfluidics, capillary chromatography, and nanolithography. In cell biology, it is often necessary to inject material of high molecular weight (e.g., DNA, proteins) into living cells because their membranes are impermeable to such molecules. All techniques currently used for microinjection are plagued by two common problems: the relatively large injector size and volume of injected fluid, and poor control of the amount of injected material. Here we demonstrate the possibility of electrochemical control of the fluid motion that allows one to sample and dispense attoliter-to-picoliter (10(-18) to 10(-12) liter) volumes of either aqueous or nonaqueous solutions. By changing the voltage applied across the liquid/liquid interface, one can produce a sufficient force to draw solution inside a nanopipette and then inject it into an immobilized biological cell. A high success rate was achieved in injections of fluorescent dyes into cultured human breast cells. The injection of femtoliter-range volumes can be monitored by video microscopy, and current/resistance-based approaches can be used to control injections from very small pipettes. Other potential applications of the electrochemical syringe include fluid dispensing in nanolithography and pumping in microfluidic systems.

Electrochemical attosyringe

PubMed Central

Laforge, François O.; Carpino, James; Rotenberg, Susan A.; Mirkin, Michael V.

2007-01-01

The ability to manipulate ultrasmall volumes of liquids is essential in such diverse fields as cell biology, microfluidics, capillary chromatography, and nanolithography. In cell biology, it is often necessary to inject material of high molecular weight (e.g., DNA, proteins) into living cells because their membranes are impermeable to such molecules. All techniques currently used for microinjection are plagued by two common problems: the relatively large injector size and volume of injected fluid, and poor control of the amount of injected material. Here we demonstrate the possibility of electrochemical control of the fluid motion that allows one to sample and dispense attoliter-to-picoliter (10−18 to 10−12 liter) volumes of either aqueous or nonaqueous solutions. By changing the voltage applied across the liquid/liquid interface, one can produce a sufficient force to draw solution inside a nanopipette and then inject it into an immobilized biological cell. A high success rate was achieved in injections of fluorescent dyes into cultured human breast cells. The injection of femtoliter-range volumes can be monitored by video microscopy, and current/resistance-based approaches can be used to control injections from very small pipettes. Other potential applications of the electrochemical syringe include fluid dispensing in nanolithography and pumping in microfluidic systems. PMID:17620612

Capillary force on a tilted cylinder: Atomic Force Microscope (AFM) measurements.

PubMed

Kosgodagan Acharige, Sébastien; Laurent, Justine; Steinberger, Audrey

2017-11-01

The capillary force in situations where the liquid meniscus is asymmetric, such as the one around a tilted object, has been hitherto barely investigated even though these situations are very common in practice. In particular, the capillary force exerted on a tilted object may depend on the dipping angle i. We investigate experimentally the capillary force that applies on a tilted cylinder as a function of its dipping angle i, using a home-built tilting Atomic Force Microscope (AFM) with custom made probes. A micrometric-size rod is glued at the end of an AFM cantilever of known stiffness, whose deflection is measured when the cylindrical probe is dipped in and retracted from reference liquids. We show that a torque correction is necessary to understand the measured deflection. We give the explicit expression of this correction as a function of the probes' geometrical parameters, so that its magnitude can be readily evaluated. The results are compatible with a vertical capillary force varying as 1/cosi, in agreement with a recent theoretical prediction. Finally, we discuss the accuracy of the method for measuring the surface tension times the cosine of the contact angle of the liquid on the probe. Copyright © 2017 Elsevier Inc. All rights reserved.

3D Printing by Multiphase Silicone/Water Capillary Inks.

PubMed

Roh, Sangchul; Parekh, Dishit P; Bharti, Bhuvnesh; Stoyanov, Simeon D; Velev, Orlin D

2017-08-01

3D printing of polymers is accomplished easily with thermoplastics as the extruded hot melt solidifies rapidly during the printing process. Printing with liquid polymer precursors is more challenging due to their longer curing times. One curable liquid polymer of specific interest is polydimethylsiloxane (PDMS). This study demonstrates a new efficient technique for 3D printing with PDMS by using a capillary suspension ink containing PDMS in the form of both precured microbeads and uncured liquid precursor, dispersed in water as continuous medium. The PDMS microbeads are held together in thixotropic granular paste by capillary attraction induced by the liquid precursor. These capillary suspensions possess high storage moduli and yield stresses that are needed for direct ink writing. They could be 3D printed and cured both in air and under water. The resulting PDMS structures are remarkably elastic, flexible, and extensible. As the ink is made of porous, biocompatible silicone that can be printed directly inside aqueous medium, it can be used in 3D printed biomedical products, or in applications such as direct printing of bioscaffolds on live tissue. This study demonstrates a number of examples using the high softness, elasticity, and resilience of these 3D printed structures. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Meniscus formation in a capillary and the role of contact line friction.

PubMed

Andrukh, Taras; Monaenkova, Daria; Rubin, Binyamin; Lee, Wah-Keat; Kornev, Konstantin G

2014-01-28

We studied spontaneous formation of an internal meniscus by dipping glass capillaries of 25 μm to 350 μm radii into low volatile hexadecane and tributyl phosphate. X-ray phase contrast and high speed optical microscopy imaging were employed. We showed that the meniscus completes its formation when the liquid column is still shorter than the capillary radius. After that, the meniscus travels about ten capillary radii at a constant velocity. We demonstrated that the experimental observations can be explained by introducing a friction force linearly proportional to the meniscus velocity with a friction coefficient depending on the air/liquid/solid triplet. It was demonstrated that the friction coefficient does not depend on the capillary radius. Numerical solution of the force balance equation revealed four different uptake regimes that can be specified in a phase portrait. This phase portrait was found to be in good agreement with the experimental results and can be used as a guide for the design of thin porous absorbers.

Motion of liquid plugs between vapor bubbles in capillary tubes: a comparison between fluids

NASA Astrophysics Data System (ADS)

Bertossi, Rémi; Ayel, Vincent; Mehta, Balkrishna; Romestant, Cyril; Bertin, Yves; Khandekar, Sameer

2017-11-01

Pulsating heat pipes (PHP) are now well-known devices in which liquid/vapor slug flow oscillates in a capillary tube wound between hot and cold sources. In this context, this paper focuses on the motion of the liquid plug, trapped between vapor bubbles, moving in capillary tubes, to try to better understand the thermo-physical phenomena involved in such devices. This study is divided into three parts. In the first part, an experimental study presents the evolution of the vapor pressure during the evaporation process of a liquid thin film deposited from a liquid plug flowing in a heated capillary tube: it is found that the behavior of the generated and removed vapor can be very different, according to the thermophysical properties of the fluids. In the second part, a transient model allows to compare, in terms of pressure and duration, the motion of a constant-length liquid plug trapped between two bubbles subjected to a constant difference of vapor pressure: the results highlight that the performances of the four fluids are also very different. Finally, a third model that can be considered as an improvement of the second one, is also presented: here, the liquid slug is surrounded by two vapor bubbles, one subjected to evaporation, the pressure in both bubbles is now a result of the calculation. This model still allows comparing the behaviors of the fluid. Even if our models are quite far from a complete model of a real PHP, results do indicate towards the applicability of different fluids as suitable working fluids for PHPs, particularly in terms of the flow instabilities which they generate.

Free silanols and ionic liquids as their suppressors in liquid chromatography.

PubMed

Buszewska-Forajta, Magdalena; Markuszewski, Michał J; Kaliszan, Roman

2018-07-20

In this review, we will firstly discuss the types and the general properties of silica, focusing on the silica support used in chromatography and capillary electrophoresis. Additionally, the characterization of functional groups (silanols and siloxanes) will be considered in terms of activity of the stationary phases. We will then discuss physical chemistry of the stationary phases applied in liquid chromatography and capillary electrophoresis. The use of ionic liquids as a silanols' suppressors will be presented in the next parts of the study, along with the examples of specific applications. The review is completed with conclusions and an outlook for the future developments in the area of analytical applications of ionic liquids. Copyright © 2018 Elsevier B.V. All rights reserved.

Direct Printing of Stretchable Elastomers for Highly Sensitive Capillary Pressure Sensors.

PubMed

Liu, Wenguang; Yan, Chaoyi

2018-03-28

We demonstrate the successful fabrication of highly sensitive capillary pressure sensors using an innovative 3D printing method. Unlike conventional capacitive pressure sensors where the capacitance changes were due to the pressure-induced interspace variations between the parallel plate electrodes, in our capillary sensors the capacitance was determined by the extrusion and extraction of liquid medium and consequent changes of dielectric constants. Significant pressure sensitivity advances up to 547.9 KPa -1 were achieved. Moreover, we suggest that our innovative capillary pressure sensors can adopt a wide range of liquid mediums, such as ethanol, deionized water, and their mixtures. The devices also showed stable performances upon repeated pressing cycles. The direct and versatile printing method combined with the significant performance advances are expected to find important applications in future stretchable and wearable electronics.

On Thermocapillary Mechanism of Spatial Separation of Metal Melts

NASA Astrophysics Data System (ADS)

Demin, V. A.; Mizev, A. I.; Petukhov, M. I.

2018-02-01

Theoretical research has been devoted to the study of binary metal melts behavior in a thin capillary. Earlier it has been found experimentally that unusually significant and quick redistribution of melts components takes place along capillary after the cooling. Numerical simulation of concentration-induced convection has been carried out to explain these experimental data. Two-component melt of both liquid metals filling vertical thin capillary with non-uniform temperature distribution on the boundaries is considered. It is assumed that the condition of absolute non-wetting is valid on the sidewalls. Because of this effect there is a free surface on vertical boundaries, where thermocapillary force is appeared due to the external longitudinal temperature gradient. It makes to move liquid elements at a big distance, compared with axial size of capillary. Effects of adsorption-desorption on the surface, thermal and concentration-capillary forces, convective motion in a volume and diffusion generate the large-scale circulation. This process includes the admixture carrying-out on the surface in the more hot higher part of the channel, its following transfer down along the boundary due to the thermocapillary force and its return in the volume over the desorption in the lower part of capillary. Intensity of motion and processes of adsorption-desorption on the free boundary have the decisive influence upon the formation of concentration fields and speed of components redistribution. Thus, one of the possible mechanisms of longitudinal division on components of liquid binary mixtures in thin channels has been demonstrated.

Solution-processing of chalcogenide materials for device applications

NASA Astrophysics Data System (ADS)

Zha, Yunlai

Chalcogenide glasses are well-known for their desirable optical properties, which have enabled many infrared applications in the fields of photonics, medicine, environmental sensing and security. Conventional deposition methods such as thermal evaporation, chemical vapor deposition, sputtering or pulse laser deposition are efficient for fabricating structures on flat surfaces. However, they have limitations in deposition on curved surfaces, deposition of thick layers and component integration. In these cases, solution-based methods, which involve the dissolution of chalcogenide glasses and processing as a liquid, become a better choice for their flexibility. After proper treatment, the associated structures can have similar optical, chemical and physical properties to the bulk. This thesis presents an in-depth study of solution-processing chalcogenide glasses, starting from the "solution state" to the "film state" and the "structure state". Firstly, chalcogenide dissolution is studied to reveal the mechanisms at molecular level and build a foundation for material processing. Dissolution processes for various chalcogenide solvent pairs are reviewed and compared. Secondly, thermal processing, in the context of high temperature annealing, is explained along with the chemical and physical properties of the annealed films. Another focus is on nanopore formation in propylamine-processed arsenic sulfide films. Pore density changes with respect to annealing temperatures and durations are characterized. Base on a proposed vacancy coalescence theory, we have identified new dissolution strategies and achieved the breakthrough of pore-free film deposition. Thirdly, several solution methods developed along with the associated photonic structures are demonstrated. The first example is "spin-coating and lamination", which produces thick (over 10 mum) chalcogenide structures. Both homogeneous thick chalcogenide structures and heterogeneous layers of different chalcogenide glasses or metals can be fabricated. Second, "micro-molding in capillaries" (MIMIC) and "micro-transfer molding" (muTM) methods are introduced for fabricating waveguides on flat and curved surfaces. The flexibility of the solution process allows waveguides to be patterned, for the first time, on a curved surface. Third, "micro channel filling" is demonstrated to produce the lowest loss among solution-processed chalcogenide waveguides. These results contribute to the advancement of chalcogenide processing technologies and help move closer towards the ultimate goal of fabricating reliable IR sensors.

β-cyclodextrin-ionic liquid polymer based dynamically coating for simultaneous determination of tetracyclines by capillary electrophoresis.

PubMed

Zhou, Chunyan; Deng, Jingjing; Shi, Guoyue; Zhou, Tianshu

2017-04-01

Tetracyclines are a group of broad spectrum antibiotics widely used in animal husbandry to prevent and treat diseases. However, the improper use of tetracyclines may result in the presence of their residues in animal tissues or waste. Recently, great attention has been drawn towards the green solvents ionic liquids. Ionic liquids have been employed as a coating material to modify the electroosmotic flow in capillary electrophoresis. In this study, a functionalized ionic liquid, mono-6-deoxy-6-(3-methylimidazolium)-β-cyclodextrin tosylate, was synthesized and used for the simultaneous separation and quantification of tetracyclines by capillary electrophoresis. Good separation efficiency could be achieved due to the multiple functions of β-cyclodextrin derived ionic liquid, including the electrostatic interaction, the hydrogen bonding, and the cavity structure in β-cyclodextrin ionic liquid which can entrap the tetracyclines to form inclusion complex. After optimization, baseline separation achieved in 25 min with the running buffer consisted of 10 mmol/L, pH 7.2 phosphate buffer and 20 mmol/L β-cyclodextrin ionic liquid. The satisfied result demonstrated that the β-cyclodextrin ionic liquid is an ideal background electrolyte modifier in the separation of tetracyclines with high stability and good reproducibility. And it is an effective strategy to design and synthesize specific ILs as additive applied in separation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Capillary liquid chromatography combined with pressurized liquid extraction and dispersive liquid-liquid microextraction for the determination of vitamin E in cosmetic products.

PubMed

Viñas, Pilar; Pastor-Belda, Marta; Campillo, Natalia; Bravo-Bravo, María; Hernández-Córdoba, Manuel

2014-06-01

Capillary liquid chromatography (LC) is used for the determination of tocopherols and tocotrienols in cosmetic products. Dispersive liquid-liquid microextraction (DLLME) allows the analytes to be preconcentrated into a very small volume of organic solvent which is then injected into the chromatograph running at a very low flow rate. Pressurized liquid extraction (PLE) at a high temperature and pressure was used to isolate vitamin E forms from cosmetics. The Taguchi experimental method was used to optimize the factors affecting DLLME. The parameters selected were 2mL of acetonitrile (disperser solvent), 100μL carbon tetrachloride (extraction solvent) and 10mL aqueous solution. A volume of 5μL of the organic phase was injected into the reversed-phase capillary LC system equipped with a diode array detector and using an isocratic mobile phase composed of an 95:5 (v/v) methanol:water mixture at a flow-rate of 20μLmin(-1). Quantification was carried out using aqueous standards and detection limits were in the range 0.1-0.5ngmL(-1), corresponding to 3-15ngg(-1) in the cosmetic sample. The recoveries were in the 87-105% range, with RSDs lower than 7.8%. The method was validated according to international guidelines and using a certified reference material. Copyright © 2014 Elsevier B.V. All rights reserved.

Droplet breakup driven by shear thinning solutions in a microfluidic T-junction

NASA Astrophysics Data System (ADS)

Chiarello, Enrico; Gupta, Anupam; Mistura, Giampaolo; Sbragaglia, Mauro; Pierno, Matteo

2017-12-01

Droplet-based microfluidics turned out to be an efficient and adjustable platform for digital analysis, encapsulation of cells, drug formulation, and polymerase chain reaction. Typically, for most biomedical applications, the handling of complex, non-Newtonian fluids is involved, e.g., synovial and salivary fluids, collagen, and gel scaffolds. In this study, we investigate the problem of droplet formation occurring in a microfluidic T-shaped junction, when the continuous phase is made of shear thinning liquids. At first, we review in detail the breakup process, providing extensive, side-by-side comparisons between Newtonian and non-Newtonian liquids over unexplored ranges of flow conditions and viscous responses. The non-Newtonian liquid carrying the droplets is made of Xanthan solutions, a stiff, rodlike polysaccharide displaying a marked shear thinning rheology. By defining an effective Capillary number, a simple yet effective methodology is used to account for the shear-dependent viscous response occurring at the breakup. The droplet size can be predicted over a wide range of flow conditions simply by knowing the rheology of the bulk continuous phase. Experimental results are complemented with numerical simulations of purely shear thinning fluids using lattice Boltzmann models. The good agreement between the experimental and numerical data confirm the validity of the proposed rescaling with the effective Capillary number.

Practical microstructured and plasmonic terahertz waveguides

NASA Astrophysics Data System (ADS)

Markov, Andrey

The terahertz frequency range, with frequencies lying between 100 GHz and 10 THz, has strong potential for various technological and scientific applications such as sensing, imaging, communications, and spectroscopy. Most terahertz (THz) sources are immobile and THz systems use free-space propagation in dry air where losses are minimal. Designing efficient THz waveguides for flexible delivery of broadband THz radiation is an important step towards practical applications of terahertz techniques. THz waveguides can be very useful on the system integration level when used for connection of the diverse THz point devices, such as sources, filters, sensor cells, detectors, etc. The most straightforward application of waveguides is to deliver electromagnetic waves from the source to the point of detection. Cumbersome free-space optics can be replaced by waveguides operating in the THz range, which could lead to the development of compact THz time domain spectroscopy systems. Other promising applications of THz waveguides are in sensing and imaging. THz waveguides have also been shown to operate in subwavelength regimes, offering mode confinement in waveguide structures with a size smaller than the diffraction limit, and thus, surpassing the resolution of free-space THz imaging systems. In order to design efficient terahertz waveguides, the frequency dependent loss and dispersion of the waveguide must be minimized. A possible solution would be to increase the fraction of mode power propagating through air. In this thesis, the usage of planar porous air/dielectric waveguides and metal wire/dielectric hybrid terahertz fibers will be discussed. First, I present a novel design of a planar porous low-loss waveguide, describe its fabrication, and characterize it in view of its potential applications as a low-loss waveguide and sensor in the THz spectral range. The waveguide structure features a periodic sequence of layers of thin (25-50 mum) polyethylene film that are separated by low-loss air layers of comparable thickness. A large fraction of the modal fields in these waveguides is guided in the low-loss air region, thus effectively reducing the waveguide transmission losses. I consider that such waveguides can be useful not only for low-loss THz wave delivery, but also for sensing of biological and chemical specimens in the terahertz region, by placing the recognition elements directly into the waveguide microstructure. The main advantage of the proposed planar porous waveguide is the convenient access to its optical mode, since the major portion of THz power launched into such a waveguide is confined within the air layers. Moreover, small spacing between the layers promotes rapid loading of the analyte into the waveguide due to strong capillary effect (< 1 s filling of a 10 cm long waveguide with an analyte). The transmission and absorption properties of such waveguides have been investigated both experimentally using THz-TDS spectroscopy and theoretically using finite element software. The modal refractive index of porous waveguides is smaller compared to pure polymer and it is easy to adjust by changing the air spacing between the layers, as well as the number of layers in the core. The porous waveguide exhibits considerably smaller transmission losses than bulk material. In the following chapters I review another promising approach towards designing of low-loss, low-dispersion THz waveguides. The hybrid metal/dielectric waveguides use a plasmonic mode guided in the gap between two parallel wires that are, in turn, encapsulated inside a low-loss, low-refractive index, micro-structured cladding that provides mechanical stability and isolation from the environment. I describe several promising techniques that can be used to encapsulate the two-wire waveguides, while minimizing the negative impact of dielectric cladding on the waveguide optical properties. In particular, I detail the use of low-density foams and microstructured plastic claddings as two enabling materials for the two-wire waveguide encapsulation. The hybrid fiber design is more convenient for practical applications than a classic two metal wire THz waveguide as it allows direct manipulations of the fiber without the risk of perturbing its core-guided mode. I present a detailed analysis of the modal properties of the hybrid metal/dielectric waveguides, compare them with the properties of a classic two-wire waveguide, and then present strategies for the improvement of hybrid waveguide performance by using higher cladding porosity or utilizing inherently porous cladding material. I study coupling efficiency into hybrid waveguides and conclude that it can be relatively high (>50%) in the broad frequency range ˜0.5 THz. Not surprisingly, optical properties of such fibers are inferior to those of a classic two-wire waveguide due to the presence of lossy dielectric near an inter-wire gap. At the same time, composite fibers outperform porous fibers of the same geometry both in bandwidth of operation and in lower dispersion. I demonstrate that hybrid metal/dielectric porous waveguides can have a very large operational bandwidth, while supporting tightly confined, air-bound modes both at high and low frequencies. This is possible as, at higher frequencies, hybrid fibers can support ARROW-like low-loss air-bound modes, while changing their guidance mechanism to plasmonic confinement in the inter-wire air gap at lower frequencies. Finally, I describe an intriguing resonant property of some hybrid plasmonic modes of metal / dielectric waveguides that manifests itself in the strong frequency dependent change in the modal confinement from dielectric-bound to air-bound. I discuss how this property can be used to construct THz refractometers. Introduction of even lossless analytes into the fiber core leads to significant changes in the modal losses, which is used as a transduction mechanism. The resolution of the refractometer has been investigated numerically as a function of the operation frequency and the geometric parameters of the fiber. With a refractive index resolution on the order of ˜10-3 RIU, the composite fiber-based sensor is capable of identifying various gaseous analytes and aerosols or measuring the concentration of dust particles in the air.

Jet dynamics post drop impact on a deep pool

NASA Astrophysics Data System (ADS)

Michon, Guy-Jean; Josserand, Christophe; Séon, Thomas

2017-02-01

We investigate experimentally the jet formed by the collapse of a cavity created by the impact of a drop on a pool of the same aqueous liquid. We show that jets can emerge with very different shapes and velocities, depending on the impact parameters, thus generating droplets with various initial sizes and velocities. After presenting the jet velocity and top drop radius variation as a function of the impact parameters, we discuss the influence of the liquid parameters on the jet velocity. This allows us to define two different regimes: the singular jet and the cavity jet regimes, where the mechanisms leading to the cavity retraction and subsequent jet dynamics are drastically different. In particular, we demonstrate that in the first regime, a singular capillary wave collapse sparks the whole jet dynamics, making the jet's fast, thin, liquid parameters dependent and barely reproducible. On the contrary, in the cavity jet regime, defined for higher impact Froude numbers, the jets are fat and slow. We show that jet velocity is simply proportional to the capillary velocity √{γ /ρlDd }, where γ is the liquid surface tension, ρl the liquid density, and Dd the impacting drop diameter, and it is in particular independent of viscosity, impact velocity, and gravity, even though the cavity is larger than the capillary length. Finally, we demonstrate that capillary wave collapse and cavity retraction are correlated in the singular regime and decorrelated in the cavity jet regime.

Reclamation of potable water from mixed gas streams

DOEpatents

Judkins, Roddie R.; Bischoff, Brian L.; Debusk, Melanie Moses; Narula, Chaitanya

2016-07-19

An apparatus for separating a liquid from a mixed gas stream can include a wall, a mixed gas stream passageway, and a liquid collection assembly. The wall can include a first surface, a second surface, and a plurality of capillary condensation pores. The capillary condensation pores extend through the wall, and have a first opening on the first surface of the wall, and a second opening on the second surface of the wall. The pore size of the pores can be between about 2 nm to about 100 nm. The mixed gas stream passageway can be in fluid communication with the first opening. The liquid collection assembly can collect liquid from the plurality of pores.

Reclamation of potable water from mixed gas streams

DOEpatents

Judkins, Roddie R; Bischoff, Brian L; Debusk, Melanie Moses; Narula, Chaitanya

2013-08-20

An apparatus for separating a liquid from a mixed gas stream can include a wall, a mixed gas stream passageway, and a liquid collection assembly. The wall can include a first surface, a second surface, and a plurality of capillary condensation pores. The capillary condensation pores extend through the wall, and have a first opening on the first surface of the wall, and a second opening on the second surface of the wall. The pore size of the pores can be between about 2 nm to about 100 nm. The mixed gas stream passageway can be in fluid communication with the first opening. The liquid collection assembly can collect liquid from the plurality of pores.

Experimental study of displacement of one liquid by another in a cylindrical capillary

NASA Astrophysics Data System (ADS)

Velizhanin, A. A.; Simonov, O. A.

2017-10-01

The single-phase flow of liquids (water and oil) in microchannels is experimentally researched, as well as the process of displacement of one liquid by another. Automatic measurements of a pressure drop, and mass of liquid which passed through a microchannel were made. Photo and video recording of the movement of the fronts of displacement was carried out. Qualitative and numerical data allowing to describe character of single-phase and two-phase flow are obtained. Comparison with the theoretical description of correspondence flows was carried out. It is established that the main characteristics of a flow through a capillary constantly change in the course of the experiment that testifies to his non-stationary character.

An approximate theoretical treatment of ion transfer processes at asymmetric microscopic and nanoscopic liquid-liquid interfaces: Single and double potential pulse techniques

NASA Astrophysics Data System (ADS)

Molina, A.; Laborda, E.; Compton, R. G.

2014-03-01

Simple theory for the electrochemical study of reversible ion transfer processes at micro- and nano-liquid|liquid interfaces supported on a capillary is presented. Closed-form expressions are obtained for the response in normal pulse and differential double pulse voltammetries, which describe adequately the particular behaviour of these systems due to the ‘asymmetric’ ion diffusion inside and outside the capillary. The use of different potential pulse techniques for the determination of the formal potential and diffusion coefficients of the ion is examined. For this, very simple analytical expressions are presented for the half-wave potential in NPV and the peak potential in DDPV.

Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet.

PubMed

Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

2017-08-01

A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples. Graphical Abstract ᅟ.

Direct Analysis of Organic Compounds in Liquid Using a Miniature Photoionization Ion Trap Mass Spectrometer with Pulsed Carrier-Gas Capillary Inlet

NASA Astrophysics Data System (ADS)

Lu, Xinqiong; Yu, Quan; Zhang, Qian; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

2017-08-01

A miniature ion trap mass spectrometer with capillary direct sampling and vacuum ultraviolet photoionization source was developed to conduct trace analysis of organic compounds in liquids. Self-aspiration sampling is available where the samples are drawn into the vacuum chamber through a capillary with an extremely low flow rate (less than 1 μL/min), which minimizes sample consumption in each analysis to tens of micrograms. A pulsed gas-assisted inlet was designed and optimized to promote sample transmission in the tube and facilitate the cooling of ions, thereby improving instrument sensitivity. A limit of detection of 2 ppb could be achieved for 2,4-dimethylaniline in a methanol solution. The sampling system described in the present study is specifically suitable for a miniature photoionization ion trap mass spectrometer that can perform rapid and online analysis for liquid samples.

Controlled crosslinking of trimethylolpropane trimethacrylate for preparation of organic monolithic columns for capillary liquid chromatography.

PubMed

Gama, Mariana R; Aggarwal, Pankaj; Lee, Milton L; Bottoli, Carla B G

2017-11-01

Organic monolithic columns based on single crosslinking of trimethylolpropane trimethacrylate (TRIM) monomer were prepared in a single step by living/controlled free-radical polymerization. Full optimization of the preparation, such as using different percentages of TRIM and different amounts of radical promoter as well as various porogen solvents were explored. The resulting monolithic columns were characterized by scanning electronic microscopy and nitrogen sorption for structure morphology studies and surface area measurements, respectively. Using capillary liquid chromatography, 150 μm i.d. columns were applied to separate a mixture of small hydrophobic molecules. The results indicated that column performance is highly sensitive to the type and the amount of porogen solvents used in the polymerization mixture composition. Good resolution factors and methylene selectivity were obtained, indicating the promising potential of this material for capillary liquid chromatography separations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Micro-column plasma emission liquid chromatograph

DOEpatents

Gay, Don D.

1984-01-01

In a direct current plasma emission spectrometer for use in combination with a micro-column liquid chromatograph, an improved plasma source unit. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

Micro-column plasma emission liquid chromatograph. [Patent application

DOEpatents

Gay, D.D.

1982-08-12

In a direct current plasma emission spectrometer for use in combination with a microcolumn liquid chromatograph, an improved plasma source unit is claimed. The plasma source unit includes a quartz capillary tube having an inlet means, outlet off gas means and a pair of spaced electrodes defining a plasma region in the tube. The inlet means is connected to and adapted to receive eluant of the liquid chromatograph along with a stream of plasma-forming gas. There is an opening through the wall of the capillary tube penetrating into the plasma region. A soft glass capillary light pipe is disposed at the opening, is connected to the spectrometer, and is adapted to transmit light passing from the plasma region to the spectrometer. There is also a source of electromotive force connected to the electrodes sufficient to initiate and sustain a plasma in the plasma region of the tube.

Wicking Tests for Unidirectional Fabrics: Measurements of Capillary Parameters to Evaluate Capillary Pressure in Liquid Composite Molding Processes.

PubMed

Pucci, Monica Francesca; Liotier, Pierre-Jacques; Drapier, Sylvain

2017-01-27

During impregnation of a fibrous reinforcement in liquid composite molding (LCM) processes, capillary effects have to be understood in order to identify their influence on void formation in composite parts. Wicking in a fibrous medium described by the Washburn equation was considered equivalent to a flow under the effect of capillary pressure according to the Darcy law. Experimental tests for the characterization of wicking were conducted with both carbon and flax fiber reinforcement. Quasi-unidirectional fabrics were then tested by means of a tensiometer to determine the morphological and wetting parameters along the fiber direction. The procedure was shown to be promising when the morphology of the fabric is unchanged during capillary wicking. In the case of carbon fabrics, the capillary pressure can be calculated. Flax fibers are sensitive to moisture sorption and swell in water. This phenomenon has to be taken into account to assess the wetting parameters. In order to make fibers less sensitive to water sorption, a thermal treatment was carried out on flax reinforcements. This treatment enhances fiber morphological stability and prevents swelling in water. It was shown that treated fabrics have a linear wicking trend similar to those found in carbon fabrics, allowing for the determination of capillary pressure.

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.

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.

Surface tension determination using liquid sample micromirror property

NASA Astrophysics Data System (ADS)

Hošek, Jan

2007-05-01

This paper presents an application of adaptive optics principle onto small sample of liquid surface tension measurement. The principle of experimental method devised by Ferguson (1924) is based on measurement of pressure difference across a liquid sample placed into small diameter capillary on condition of one flat meniscus of the liquid sample. Planarity or curvature radius of the capillary tip meniscus has to be measured and controlled, in order to fulfill this condition during measurement. Two different optical set-ups using liquid meniscus micromirror property are presented and its suitability for meniscus profile determination is compared. Meniscus radius optical measurement, data processing and control algorithm of the adaptive micromirror profile set are presented too. The presented adaptive optics system can be used for focal length control of microsystems based on liquid micromirrors or microlenses with long focal distances especially.

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

NASA Technical Reports Server (NTRS)

Lekan, Jack F.; Allen, Jeffrey S.

1998-01-01

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

Design and performance of a high-Tc superconductor coplanar waveguide filter

NASA Technical Reports Server (NTRS)

Chew, Wilbert; Riley, A. L.; Rascoe, Daniel L.; Hunt, Brian D.; Foote, Marc C.; Cooley, Thomas W.; Bajuk, Louis J.

1991-01-01

The design of a coplanar waveguide low-pass filter made of YBa2Cu3O(7-delta) (YBCO) on an LaAlO3 substrate is described. Measurements were incorporated into simple models for microwave CAD analysis to develop a final design. The patterned and packaged coplanar waveguide low-pass filter of YBCO, with dimensions suited for integrated circuits, exhibited measured insertion losses when cooled in liquid nitrogen superior to those of a similarly cooled thin-film copper filter throughout the 0 to 9.5 GHz passband. Coplanar waveguide models for use with thin-film normal metal (with thickness either greater or less than the skin depth) and YBCO are discussed and used to compare the losses of the measured YBCO and copper circuits.

Cfd Simulation of Capillary Rise of Liquid in Cylindrical Container with Lateral Vanes

NASA Astrophysics Data System (ADS)

Liu, Xiaolin; Huang, Yiyong; Li, Guangyu

2016-06-01

Orbit refueling is one of the most significant technologies, which has vital strategic meaning. It can enhance the flexibility and prolong the lifetime of the spacecrafts. Space propellant management is one of the key technologies in orbit refueling. Based on the background of space propellant management, CFD simulations of capillary rise of liquid in Cylindrical container with lateral vanes in space condition were carried out in this paper. The influence of the size and the number of the vanes to the capillary flow were analyzed too. The results can be useful to the design and optimization of the propellant management device in the vane type surface tension tank.

Printing polymer optical waveguides on conditioned transparent flexible foils by using the aerosol jet technology

NASA Astrophysics Data System (ADS)

Reitberger, Thomas; Hoffmann, Gerd-Albert; Wolfer, Tim; Overmeyer, Ludger; Franke, Joerg

2016-09-01

The optical data transfer is considered as the future of signal transfer due to its various advantages compared to conventional copper-based technologies. The Aerosol Jet Printing (AJP) technology offers the opportunity to print materials with high viscosities, such as liquid transparent polymer adhesives (epoxy resins), on almost any possible substrate material and even in third dimension. This paper introduces a new flexible and comparatively cost-effective way of generating polymer optical waveguides through AJP. Furthermore, the conditioning of the substrate material and the printing process of planar waveguides are presented. In the first step, two lines with hydrophobic behavior are applied on foil material (PMMA, PVC, PI) by using a flexographic printing machine. These silicone based patterns containing functional polymer form barriers for the core material due to their low surface energy after curing. In the second step, the core material (liquid polymer, varnish) is printed between the barrier lines. Because of the hydrophobic behavior of the lines, the contact angle between the substrate surface and the liquid core material is increased which yields to higher aspect ratio. The distance between the barrier lines is at least 100 μm, which defines the width of the waveguide. The minimum height of the core shall be 50 μm. After UV-curing of the core polymer, the cladding material is printed on the top. This is also applied by using the AJP technology. Various tests were performed to achieve the optimal surface properties for adequate adhesion and machine process parameters.

Motion of deformable drops through granular media and other confined geometries.

PubMed

Davis, Robert H; Zinchenko, Alexander Z

2009-06-15

This article features recent simulation studies of the flow of emulsions containing deformable drops through pores, constrictions, and granular media. The flow is assumed to be at low Reynolds number, so that viscous forces dominate, and boundary-integral methods are used to determine interfacial velocities and, hence, track the drop motion and shapes. A single drop in a flat channel migrates to the channel centerplane due to deformation-induced drift, which increases its steady-state velocity along the channel. A drop moving towards a smaller interparticle constriction squeezes through the constriction if the capillary number (ratio of viscous deforming forces and interfacial tension forces) is large enough, but it becomes trapped when the capillary number is below a critical value. These concepts then influence the flow of an emulsion through a granular medium, for which the drop phase moves faster than the suspending liquid at large capillary numbers but slower than the suspending liquid at smaller capillary numbers. The permeabilities of the granular medium to both phases increase with increasing capillary number, due to the reduced resistance to squeezing of easily deformed drops, though drop breakup must also be considered at large capillary numbers.

Profile of capillary bridges between two vertically stacked cylindrical fibers under gravitational effect

NASA Astrophysics Data System (ADS)

Sun, Xiaohang; Lee, Hoon Joo; Michielsen, Stephen; Wilusz, Eugene

2018-05-01

Although profiles of axisymmetric capillary bridges between two cylindrical fibers have been extensively studied, little research has been reported on capillary bridges under external forces such as the gravitational force. This is because external forces add significant complications to the Laplace-Young equation, making it difficult to predict drop profiles based on analytical approaches. In this paper, simulations of capillary bridges between two vertically stacked cylindrical fibers with gravitational effect taken into consideration are studied. The asymmetrical structure of capillary bridges that are hard to predict based on analytical approaches was studied via a numerical approach based on Surface Evolver (SE). The axial and the circumferential spreading of liquids on two identical fibers in the presence of gravitational effects are predicted to determine when the gravitational effects are significant or can be neglected. The effect of liquid volume, equilibrium contact angle, the distance between two fibers and fiber radii. The simulation results were verified by comparing them with experimental measurements. Based on SE simulations, curves representing the spreading of capillary bridges along the two cylindrical fibers were obtained. The gravitational effect was scaled based on the difference of the spreading on upper and lower fibers.

Capillary zone electrophoresis-tandem mass spectrometry detects low concentration host cell impurities in monoclonal antibodies

PubMed Central

Zhu, Guijie; Sun, Liangliang; Heidbrink-Thompson, Jennifer; Kuntumalla, Srilatha; Lin, Hung-yu; Larkin, Christopher J.; McGivney, James B.; Dovichi, Norman J.

2016-01-01

We have evaluated capillary zone electrophoresis-electrospray ionization-tandem mass spectrometry (CZE-ESI-MS/MS) for detection of trace amounts of host cell protein impurities in recombinant therapeutics. Compared to previously published procedures, we have optimized the buffer pH used in the formation of a pH junction to increase injection volume. We also prepared a five-point calibration curve by spiking twelve standard proteins into a solution of a human monoclonal antibody. A custom CZE-MS/MS system was used to analyze the tryptic digest of this mixture without depletion of the antibody. CZE generated a ~70 min separation window (~90 min total analysis duration) and ~300 peak capacity. We also analyzed the sample using ultra-performance liquid chromatography (UPLC)-MS/MS. CZE-MS/MS generated ~five times higher base peak intensity and more peptide identifications for low-level spiked proteins. Both methods detected all proteins spiked at the ~100 ppm level with respect to the antibody. PMID:26530276

High-speed video capillaroscopy method for imaging and evaluation of moving red blood cells

NASA Astrophysics Data System (ADS)

Gurov, Igor; Volkov, Mikhail; Margaryants, Nikita; Pimenov, Aleksei; Potemkin, Andrey

2018-05-01

The video capillaroscopy system with high image recording rate to resolve moving red blood cells with velocity up to 5 mm/s into a capillary is considered. Proposed procedures of the recorded video sequence processing allow evaluating spatial capillary area, capillary diameter and central line with high accuracy and reliability independently on properties of individual capillary. Two-dimensional inter frame procedure is applied to find lateral shift of neighbor images in the blood flow area with moving red blood cells and to measure directly the blood flow velocity along a capillary central line. The developed method opens new opportunities for biomedical diagnostics, particularly, due to long-time continuous monitoring of red blood cells velocity into capillary. Spatio-temporal representation of capillary blood flow is considered. Experimental results of direct measurement of blood flow velocity into separate capillary as well as capillary net are presented and discussed.

Modeling the Capillary Pressure for the Migration of the Liquid Phase in Granular Solid-Liquid-Vapor Systems: Application to the Control of the Composition Profile in W-Cu FGM Materials

NASA Astrophysics Data System (ADS)

Missiaen, Jean-Michel; Raharijaona, Jean-Joël; Delannay, Francis

2016-11-01

A model is developed to compute the capillary pressure for the migration of the liquid phase out or into a uniform solid-liquid-vapor system. The capillary pressure is defined as the reduction of the overall interface energy per volume increment of the transferred fluid phase. The model takes into account the particle size of the solid particle aggregate, the packing configuration (coordination number, porosity), the volume fractions of the different phases, and the values of the interface energies in the system. The model is used for analyzing the stability of the composition profile during processing of W-Cu functionally graded materials combining a composition gradient with a particle size gradient. The migration pressure is computed with the model in two stages: (1) just after the melting of copper, i.e., when sintering and shape accommodation of the W particle aggregate can still be neglected and (2) at high temperature, when the system is close to full density with equilibrium particle shape. The model predicts well the different stages of liquid-phase migration observed experimentally.

Dynamics of the liquid film around elongated bubbles rising in vertical capillaries

NASA Astrophysics Data System (ADS)

Magnini, Mirco; Khodaparast, Sepideh; Matar, Omar K.; Stone, Howard A.; Thome, John R.

2017-11-01

We performed a theoretical, numerical and experimental study on elongated bubbles rising in vertical tubes in co-current liquid flows. The flow conditions were characterized by capillary, Reynolds and Bond numbers within the range of Ca = 0.005 - 0.1 , Re = 1 - 2000 and Bo = 0 - 20 . Direct numerical simulations of the two-phase flows are run with a self-improved version of OpenFOAM, implementing a coupled Level Set and Volume of Fluid method. A theoretical model based on an extension of the traditional Bretherton theory, accounting for inertia and the gravity force, is developed to obtain predictions of the profiles of the front and rear menisci of the bubble, liquid film thickness and bubble velocity. Different from the traditional theory for bubbles rising in a stagnant liquid, the gravity force impacts the flow already when Bo < 4 . Gravity effects speed up the bubble compared to the Bo = 0 case, making the liquid film thicker and reducing the amplitude of the undulation on the surface of the bubble near its tail. Gravity effects are more apparent in the visco-capillary regime, i.e. when the Reynolds number is below 1.

Directional, passive liquid transport: the Texas horned lizard as a model for a biomimetic 'liquid diode'.

PubMed

Comanns, Philipp; Buchberger, Gerda; Buchsbaum, Andreas; Baumgartner, Richard; Kogler, Alexander; Bauer, Siegfried; Baumgartner, Werner

2015-08-06

Moisture-harvesting lizards such as the Texas horned lizard (Iguanidae: Phrynosoma cornutum) live in arid regions. Special skin adaptations enable them to access water sources such as moist sand and dew: their skin is capable of collecting and transporting water directionally by means of a capillary system between the scales. This fluid transport is passive, i.e. requires no external energy, and directs water preferentially towards the lizard's snout. We show that this phenomenon is based on geometric principles, namely on a periodic pattern of interconnected half-open capillary channels that narrow and widen. Following a biomimetic approach, we used these principles to develop a technical prototype design. Building upon the Young-Laplace equation, we derived a theoretical model for the local behaviour of the liquid in such capillaries. We present a global model for the penetration velocity validated by experimental data. Artificial surfaces designed in accordance with this model prevent liquid flow in one direction while sustaining it in the other. Such passive directional liquid transport could lead to process improvements and reduction of resources in many technical applications. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Time-resolved observation of thermally activated rupture of a capillary-condensed water nanobridge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bak, Wan; Sung, Baekman; Kim, Jongwoo

2015-01-05

The capillary-condensed liquid bridge is one of the most ubiquitous forms of liquid in nature and contributes significantly to adhesion and friction of biological molecules as well as microscopic objects. Despite its important role in nanoscience and technology, the rupture process of the bridge is not well understood and needs more experimental works. Here, we report real-time observation of rupture of a capillary-condensed water nanobridge in ambient condition. During slow and stepwise stretch of the nanobridge, we measured the activation time for rupture, or the latency time required for the bridge breakup. By statistical analysis of the time-resolved distribution ofmore » activation time, we show that rupture is a thermally activated stochastic process and follows the Poisson statistics. In particular, from the Arrhenius law that the rupture rate satisfies, we estimate the position-dependent activation energies for the capillary-bridge rupture.« less

Molar volume and adsorption isotherm dependence of capillary forces in nanoasperity contacts.

PubMed

Asay, David B; Kim, Seong H

2007-11-20

The magnitude of the capillary force at any given temperature and adsorbate partial pressure depends primarily on four factors: the surface tension of the adsorbate, its liquid molar volume, its isothermal behavior, and the contact geometry. At large contacting radii, the adsorbate surface tension and the contact geometry are dominating. This is the case of surface force apparatus measurements and atomic force microscopy (AFM) experiments with micrometer-size spheres. However, as the size of contacting asperities decreases to the nanoscale as in AFM experiments with sharp tips, the molar volume and isotherm of the adsorbate become very important to capillary formation as well as capillary adhesion. This effect is experimentally and theoretically explored with simple alcohol molecules (ethanol, 1-butanol, and 1-pentanol) which have comparable surface tensions but differing liquid molar volumes. Adsorption isotherms for these alcohols on silicon oxide are also reported.

Coherent X-ray Scattering from Liquid-Air Interfaces

NASA Astrophysics Data System (ADS)

Shpyrko, Oleg

Advances in synchrotron x-ray scattering techniques allow studies of structure and dynamics of liquid surfaces with unprecedented resolution. I will review x-ray scattering measurements of thermally excited capillary fluctuations in liquids, thin polymer liquid films and polymer surfaces in confined geometry. X-ray Diffuse scattering profile due to Debye-Waller like roughening of the surface allows to probe the distribution of capillary fluctuations over a wide range of length scales, while using X-ray Photon Correlation Spectroscopy (XPCS) one is able to directly couple to nanoscale dynamics of these surface fluctuations, over a wide range of temporal and spacial scales. I will also discuss recent XPCS measurements of lateral diffusion dynamics in Langmuir monolayers assembled at the liquid-air interface. This research was supported by NSF CAREER Grant 0956131.

Stripe-like Clay Nanotubes Patterns in Glass Capillary Tubes for Capture of Tumor Cells.

PubMed

Liu, Mingxian; He, Rui; Yang, Jing; Zhao, Wei; Zhou, Changren

2016-03-01

Here, we used capillary tubes to evaporate an aqueous dispersion of halloysite nanotubes (HNTs) in a controlled manner to prepare a patterned surface with ordered alignment of the nanotubes . Sodium polystyrenesulfonate (PSS) was added to improve the surface charges of the tubes. An increased negative charge of HNTs is realized by PSS coating (from -26.1 mV to -52.2 mV). When the HNTs aqueous dispersion concentration is higher than 10%, liquid crystal phenomenon of the dispersion is found. A typical shear flow behavior and decreased viscosity upon shear is found when HNTs dispersions with concentrations higher than 10%. Upon drying the HNTs aqueous dispersion in capillary tubes, a regular pattern is formed in the wall of the tube. The width and spacing of the bands increase with HNTs dispersion concentration and decrease with the drying temperature for a given initial concentration. Morphology results show that an ordered alignment of HNTs is found especially for the sample of 10%. The patterned surface can be used as a model for preparing PDMS molding with regular micro-/nanostructure. Also, the HNTs rough surfaces can provide much higher tumor cell capture efficiency compared to blank glass surfaces. The HNTs ordered surfaces provide promising application for biomedical areas such as biosensors.

Oscillation of an isolated liquid plug inside a dry capillary

NASA Astrophysics Data System (ADS)

Srinivasan, Vyas; Kumar, Siddhartha; Asfer, Mohammed; Khandekar, Sameer

2017-11-01

The present work reports an experimental study on the dynamics of partially wetting isolated liquid plug (DI water), which is made to oscillate inside a square, glass capillary tube (1 mm × 1 mm; 60 mm length). The liquid plug is made to oscillate pneumatically at two different frequencies (0.25 and 0.35 Hz), using a cam-follower mechanism. Bright field imaging is used to visualize the three-phase contact line behavior, while, micro-Particle Imaging Velocimetry (PIV) apparatus is used to discern the nature of flow inside the oscillating liquid plug. During a cycle, due to the partial wetting nature of DI water, the three-phase contact line at the menisci gets pinned at the extreme end of each stroke, where the dynamic apparent contact angle gets drastically altered before the initiation of the next stroke. The difference between the apparent contact angle of the front and rear meniscus are seen to be a function of the oscillating frequency; the difference increasing with increasing frequency. The flow inside the liquid plug reveals unique non-Poiseuille flow features near the meniscus, due to free-slip boundary condition, which leads to formation of distinct vortex pairs behind it. The vortices too change their direction during each stroke of the oscillation, eventually leading to an alternating recirculation pattern inside the plug. The results clearly indicate that improved mathematical models are required for predicting transport parameters in such flows, which are important in engineering systems such as pulsating heat pipes, lab-on-chip devices and PEM fuel cells.

Low-Loss Coupling of Quantum Cascade Lasers into Hollow-Core Waveguides with Single-Mode Output in the 3.7-7.6 μm Spectral Range.

PubMed

Patimisco, Pietro; Sampaolo, Angelo; Mihai, Laura; Giglio, Marilena; Kriesel, Jason; Sporea, Dan; Scamarcio, Gaetano; Tittel, Frank K; Spagnolo, Vincenzo

2016-04-13

We demonstrated low-loss and single-mode laser beam delivery through hollow-core waveguides (HCWs) operating in the 3.7-7.6 μm spectral range. The employed HCWs have a circular cross section with a bore diameter of 200 μm and metallic/dielectric internal coatings deposited inside a glass capillary tube. The internal coatings have been produced to enhance the spectral response of the HCWs in the range 3.5-12 µm. We demonstrated Gaussian-like outputs throughout the 4.5-7.6 µm spectral range. A quasi single-mode output beam with only small beam distortions was achieved when the wavelength was reduced to 3.7 μm. With a 15-cm-long HCW and optimized coupling conditions, we measured coupling efficiencies of >88% and transmission losses of <1 dB in the investigated infrared spectral range.

Quantification of bulk solution limits for liquid and interfacial transport in nanoconfinements.

PubMed

Kelly, Shaina; Balhoff, Matthew T; Torres-Verdín, Carlos

2015-02-24

Liquid imbibition, the capillary-pressure-driven flow of a liquid into a gas, provides a mechanism for studying the effects of solid-liquid and solid-liquid-gas interfaces on nanoscale transport. Deviations from the classic Washburn equation for imbibition are generally observed for nanoscale imbibition, but the identification of the origin of these irregularities in terms of transport variables varies greatly among investigators. We present an experimental method and corresponding image and data analysis scheme that enable the determination of independent effective values of nanoscale capillary pressure, liquid viscosity, and interfacial gas partitioning coefficients, all critical transport variables, from imbibition within nanochannels. Experiments documented herein are performed within two-dimensional siliceous nanochannels of varying size and as small as 30 nm × 60 nm in cross section. The wetting fluid used is the organic solvent isopropanol and the nonwetting fluid is air, but investigations are not limited to these fluids. Optical data of dynamic flow are rare in geometries that are nanoscale in two dimensions due to the limited resolution of optical microscopy. We are able to capture tracer-free liquid imbibition with reflected differential interference contrast microscopy. Results with isopropanol show a significant departure from bulk transport values in the nanochannels: reduced capillary pressures, increased liquid viscosity, and nonconstant interfacial mass-transfer coefficients. The findings equate to the nucleation of structured, quasi-crystalline boundary layers consistently ∼10-25 nm in extent. This length is far thicker than the boundary layer range prescribed by long-range intermolecular force interactions. Slower but linear imbibition in some experimental cases suggests that structured boundary layers may inhibit viscous drag at confinement walls for critical nanochannel dimensions. Probing the effects of nanoconfinement on the definitions of capillary pressure, viscosity, and interfacial mass transfer is critical in determining and improving the functionality and fluid transport efficacy of geological, biological, and synthetic nanoporous media and materials.

Extraction and Quantitation of Ketones and Aldehydes from Mammalian Cells Using Fluorous Tagging and Capillary LC-MS.

PubMed

Yuan, Wei; Li, Shuwei; Edwards, James L

2015-08-04

The extraction and quantitation of carbonyl metabolites from cell lysate was accomplished using a carbonyl-reactive fluorous tag and capillary liquid chromatography coupled to mass spectrometry (capLC-MS). Selective fluorous tagging for ketones and aldehydes provided a 30-fold increase in sensitivity using electrospray ionization MS. Separation of fluorous tagged carbonyl resulted in good separation of all components, and tandem MS was able to differentiate structural carbonyl isomers. The average limit of detection for carbonyl standards was 37 nM (range 1.5-250 nM), with linearity of R(2) > 0.99. Reproducibility for metabolites in cell lysate averaged 9% RSD. Human aortic endothelial cells (HAECs) were exposed to varying levels of glucose, and their carbonyl metabolite levels were quantified. Significant metabolite changes were seen in glycolysis and the propanoate pathway from a glucose challenge. Using an untargeted approach, 120 carbonyl metabolites were found to change in hyperglycemic HAECs. From this list of compounds, multiple metabolites from the pentose phosphate and tryptophan metabolic pathways were discovered. This system provides excellent sensitivity and quantitation of carbonyl metabolites without the need for isotope standards or labels.

Capillary descent.

PubMed

Delannoy, Joachim; de Maleprade, Hélène; Clanet, Christophe; Quéré, David

2018-05-31

A superhydrophobic capillary tube immersed in water and brought in contact with the bath surface will be invaded by air, owing to its aerophilicity. We discuss this phenomenon where the ingredients of classical capillary rise are inverted, which leads to noticeable dynamical features. (1) The main regime of air invasion is linear in time, due to the viscous resistance of water. (2) Menisci in tubes with millimetre-size radii strongly oscillate before reaching their equilibrium depth, a consequence of inertia. On the whole, capillary descent provides a broad variety of dynamics where capillary effects, viscous friction and liquid inertia all play a role.

Laser-driven acceleration of electrons in a partially ionized plasma channel.

PubMed

Rowlands-Rees, T P; Kamperidis, C; Kneip, S; Gonsalves, A J; Mangles, S P D; Gallacher, J G; Brunetti, E; Ibbotson, T; Murphy, C D; Foster, P S; Streeter, M J V; Budde, F; Norreys, P A; Jaroszynski, D A; Krushelnick, K; Najmudin, Z; Hooker, S M

2008-03-14

The generation of quasimonoenergetic electron beams, with energies up to 200 MeV, by a laser-plasma accelerator driven in a hydrogen-filled capillary discharge waveguide is investigated. Injection and acceleration of electrons is found to depend sensitively on the delay between the onset of the discharge current and the arrival of the laser pulse. A comparison of spectroscopic and interferometric measurements suggests that injection is assisted by laser ionization of atoms or ions within the channel.

Application of Temperature-Dependent Fluorescent Dyes to the Measurement of Millimeter Wave Absorption in Water Applied to Biomedical Experiments

PubMed Central

Popenko, Oleksandr

2014-01-01

Temperature sensitivity of the fluorescence intensity of the organic dyes solutions was used for noncontact measurement of the electromagnetic millimeter wave absorption in water. By using two different dyes with opposite temperature effects, local temperature increase in the capillary that is placed inside a rectangular waveguide in which millimeter waves propagate was defined. The application of this noncontact temperature sensing is a simple and novel method to detect temperature change in small biological objects. PMID:25435859

Application of temperature-dependent fluorescent dyes to the measurement of millimeter wave absorption in water applied to biomedical experiments.

PubMed

Kuzkova, Nataliia; Popenko, Oleksandr; Yakunov, Andrey

2014-01-01

Temperature sensitivity of the fluorescence intensity of the organic dyes solutions was used for noncontact measurement of the electromagnetic millimeter wave absorption in water. By using two different dyes with opposite temperature effects, local temperature increase in the capillary that is placed inside a rectangular waveguide in which millimeter waves propagate was defined. The application of this noncontact temperature sensing is a simple and novel method to detect temperature change in small biological objects.

Waveguide infrared spectrometer platform for point and standoff chemical sensing

NASA Astrophysics Data System (ADS)

Chadha, Suneet; Henning, Pat; Landers, Frank; Weling, Ani

2004-03-01

Advanced autonomous detection of chemical warfare agents and toxic industrial chemicals has long been a major military concern. At present, our capability to rapidly assess the immediate environment is severely limited and our domestic infrastructure is burdened by the meticulous procedures required to rule out false threats. While significant advances have recently been accomplished in remote spectral sensing using rugged FTIRs and point detectors, efforts towards low cost chemical discrimination have been lacking. Foster-Miller has developed a unique waveguide spectrometer which is a paradigm shift from the conventional FTIR approach. The spectrometer provides spectral discrimination over the 3-14 μm range and will be the spectrometer platform for both active and passive detection. Foster-Miller has leveraged its innovations in infrared fiber-optic probes and the recent development of a waveguide spectrometer to build a novel infrared sensor platform for both point and stand-off chemical sensing. A monolithic wedge-grating optic provides the spectral dispersion with low cost thermopile point or array detectors picking off the diffracted wavelengths from the optic. The integrated optic provides spectral discrimination between 3-12 μm with resolution at 16 cm-1 or better and overall optical throughput approaching 35%. The device has a fixed cylindrical grating bonded to the edge of a ZnSe conditioning "wedge". The conditioning optic overcomes limitations of concave gratings as it accepts high angle (large FOV) light at the narrow end of the wedge and progressively conditions it to be near normal to the grating. On return, the diffracted wavelengths are concentrated on the discrete or array detector (pixel) elements by the wedge, providing throughput comparable to that of an FTIR. The waveguide spectrometer coupled to ATR probes, flow through liquid cells or multipass gas cells provides significant cost advantage over conventional sampling methodologies. We will present the enabling innovations along with present performance, sensitivity expectations and discrimination algorithm strategy.

Droplet spreading and capillary imbibition in a porous medium: A coupled IB-VOF method based numerical study

NASA Astrophysics Data System (ADS)

Das, Saurish; Patel, H. V.; Milacic, E.; Deen, N. G.; Kuipers, J. A. M.

2018-01-01

We investigate the dynamics of a liquid droplet in contact with a surface of a porous structure by means of the pore-scale level, fully resolved numerical simulations. The geometrical details of the solid porous matrix are resolved by a sharp interface immersed boundary method on a Cartesian computational grid, whereas the motion of the gas-liquid interface is tracked by a mass conservative volume of fluid method. The numerical simulations are performed considering a model porous structure that is approximated by a 3D cubical scaffold with cylindrical struts. The effect of the porosity and the equilibrium contact angle (between the gas-liquid interface and the solid struts) on the spreading behavior, liquid imbibition, and apparent contact angle (between the gas-liquid interface and the porous base) are studied. We also perform several simulations for droplet spreading on a flat surface as a reference case. Gas-liquid systems of the Laplace number, La = 45 and La = 144 × 103 are considered neglecting the effect of gravity. We report the time exponent (n) and pre-factor (C) of the power law describing the evolution of the spreading diameter (S = Ctn) for different equilibrium contact angles and porosity. Our simulations reveal that the apparent or macroscopic contact angle varies linearly with the equilibrium contact angle and increases with porosity. Not necessarily for all the wetting porous structures, a continuous capillary drainage occurs, and we find that the rate of the capillary drainage very much depends on the fluid inertia. At La = 144 × 103, numerically we capture the capillary wave induced pinch-off and daughter droplet ejection. We observe that on the porous structure the pinch-off is weak compared to that on a flat plate.

A variational approach to the study of capillary phenomena

NASA Technical Reports Server (NTRS)

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

1982-01-01

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

Anti-infiltration for fabrication of a suspended nanoparticle layer on porous close-packed colloidal arrays.

PubMed

Teh, Lay K; Yan, Qingfeng; Wong, Chee C

2009-04-01

We develop a new method to fabricate suspended sheets of nanocrystals (NCs) on porous surfaces. The method relies on the resistance of an aqueous suspension droplet to infiltrate a porous network; hence, the method is named anti-infiltration. The process works by combining fluid dynamics of a liquid droplet during impact/absorption onto a porous surface with the convective self-assembly of NCs. The immobilization of the liquid droplet edge due to the self-assembly of NCs at the meniscus is harnessed to halt the lateral spreading of the droplet and, consequently, the capillary penetration of the liquid immediately after droplet impact. Further capillary penetration of the liquid is drastically reduced because of the competition between capillary forces and convective losses as well as the rapid occlusion of the pores as soon as a continuous NC film has formed upon evaporation of the suspension. This method holds promise for a wide variety of optoelectronic, sensing, and separation membrane applications. As an example, we demonstrate that these suspended NC layers are suitable candidates as planar defects embedded within a colloidal photonic crystal.

Aqueous carrier waveguide in a flow cytometer

DOEpatents

Mariella, Jr., Raymond P.; van den Engh, Gerrit; Northrup, M. Allen

1995-01-01

The liquid of a flow cytometer itself acts as an optical waveguide, thus transmitting the light to an optical filter/detector combination. This alternative apparatus and method for detecting scattered light in a flow cytometer is provided by a device which views and detects the light trapped within the optical waveguide formed by the flow stream. A fiber optic or other light collecting device is positioned within the flow stream. This provides enormous advantages over the standard light collection technique which uses a microscope objective. The signal-to-noise ratio is greatly increased over that for right-angle-scattered light collected by a microscope objective, and the alignment requirements are simplified.

Near-field optical technique applied for investigation of the characteristics of polymer fiber and waveguide structures.

PubMed

Ming, Hai; Tang, Lin; Sun, Xiaohong; Zhang, Jiangying; Wang, Pei; Lu, Yonghua; Bai, Ming; Guo, Yang; Xie, Aifang; Zhang, Zebo

2004-01-01

This article summarizes the near-field optical technique applied for investigating the characteristics of polymer fiber and waveguide structures. The near-field optical technique is used to analyze multimode interference structures of fiber. The localized fluctuation of the transmission caused by fractal cluster is carried out in Nd3+- and Eu3+-doped polymer fiber and film by means of a scanning near-field optical microscopy. The near-field optical spectrum of Nd3+-doped polymer fiber is investigated. The topography and near-field intensity images of Azo-polymer liquid crystal film for waveguide are obtained simultaneously.

Effect of surfactant on kinetics of thinning of capillary bridges

NASA Astrophysics Data System (ADS)

Nowak, Emilia; Kovalchuk, Nina; Simmons, Mark

2015-11-01

Kinetics of thinning of capillary bridges is of great scientific and industrial interest being of vital importance for example in various emulsification and microfluidic processes. It is well known that the rate of bridge thinning is proportional to the interfacial tension. Therefore it is expected that the process should slow down by addition of surfactant. The kinetics of capillary bridges in the presence of surfactant was studied by the dripping of liquid from a capillary tip under conditions of nearly zero flow rate (We << 1). The tested liquids were aqueous solutions of sodium lauryl ether sulphate (SLES), which is broadly used in personal care products. The viscosity, surfactant activity and adsorption kinetics have been controlled by addition of glycerol and sodium chloride. The study has shown that the kinetics of capillary bridges are determined by dynamic surface tension rather than by its equilibrium value. In particular, the kinetics of the bridge thinning for the 0.1 g L-1 aqueous SLES solution is practically the same as that of pure water despite twice lower equilibrium surface tension. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

Regioisomeric and enantiomeric analyses of 24 designer cathinones and phenethylamines using ultra high performance liquid chromatography and capillary electrophoresis with added cyclodextrins.

PubMed

Li, Li; Lurie, Ira S

2015-09-01

DESIGNER: phenethylamines (PEAs) and cathinones have been encountered worldwide. Complete characterization of these substances can be challenging due to their chirality and variably substituted phenyl rings. In this study, 24 PEAs and cathinones were analyzed by ultra high performance liquid chromatography with photo diode array detection (UHPLC-PDA) on a variety of stationary phases, and by capillary electrophoresis on a dynamically coated capillary with PDA detection (CE-PDA). In the UHPLC-PDA study, a BEH Phenyl column resolved 18 of the 24 regioisomers in 8min, with good discrimination of the PEAs. In contrast, capillary zone electrophoresis (CZE) on a dynamically coated capillary partially or baseline resolved only 10 of the 24 regioisomers, but with improved discrimination of mono-substituted cathinones. A second series of CE-PDA experiments using 80mM (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) in the run buffer resolved all 24 regioisomers and all but two sets of enantiomers within 18min. Five illicit samples were successfully analyzed using the described methods. Published by Elsevier Ireland Ltd.

Harvesting liquid from unsaturated vapor - nanoflows induced by capillary condensation

NASA Astrophysics Data System (ADS)

Vincent, Olivier; Marguet, Bastien; Stroock, Abraham

2016-11-01

A vapor, even subsaturated, can spontaneously form liquid in nanoscale spaces. This process, known as capillary condensation, plays a fundamental role in various contexts, such as the formation of clouds or the dynamics of hydrocarbons in the geological subsurface. However, large uncertainties remain on the thermodynamics and fluid mechanics of the phenomenon, due to experimental challenges as well as outstanding questions about the validity of macroscale physics at the nanometer scale. We studied experimentally the spatio-temporal dynamics of water condensation in a model nanoporous medium (pore radius 2 nm), taking advantage of the color change of the material upon hydration. We found that at low relative humidities (< 60 % RH), capillary condensation progressed in a diffusive fashion, while it occurred through a well-defined capillary-viscous imbibition front at > 60 % RH, driven by a balance between the pore capillary pressure and the condensation stress given by Kelvin equation. Further analyzing the imbibition dynamics as a function of saturation allowed us to extract detailed information about the physics of nano-confined fluids. Our results suggest excellent extension of macroscale fluid dynamics and thermodynamics even in pores 10 molecules in diameter.

Liquid metal porous matrix sliding electrical contact: A concept

NASA Technical Reports Server (NTRS)

Ferguson, H.

1973-01-01

Concept utilizes porous metal or nonmetal matrix containing liquid metal in porous structure and confines liquid metal to contact area between rotor and brush by capillary forces. System may also be used to lubricate bearing systems.

CFE-2 Experiment Run

NASA Image and Video Library

2013-11-11

View of Flight Engineer (FE) Mike Hopkins initiating a CFE-2 (Capillary Flow Experiment - 2) Interior Corner Flow - 5 (ICF-5) test run. Liquids behave differently in space than they do on Earth, so containers that can process, hold or transport them must be designed carefully to work in microgravity. The Capillary Flow Experiment-2 furthers research on wetting, which is a liquid's ability to spread across a surface, and its impact over large length scales in strange container shapes in microgravity environments. This work will improve our capabilities to quickly and accurately predict how related processes occur, and allow us to design better systems to process liquids aboard spacecraft (i.e., liquid fuel tanks, thermals fluids, and water processing for life support). Image was released by astronaut on Twitter.

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

NASA Astrophysics Data System (ADS)

Prisniakov, K.

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

Study on stair-step liquid triggered capillary valve for microfluidic systems

NASA Astrophysics Data System (ADS)

Zhang, Lei; Jones, Ben; Majeed, Bivragh; Nishiyama, Yukari; Okumura, Yasuaki; Stakenborg, Tim

2018-06-01

In lab-on-a-chip systems, various microfluidic technologies are being developed to handle fluids at very small quantities, e.g. in the scale of nano- or pico-liter. To achieve autonomous fluid handling at a low cost, passive fluidic control, based on the capillary force between the liquid and microchannel surface, is of the utmost interest in the microsystem. Valves are an essential component for flow control in many microfluidic systems, which enables a sequence of fluidic operations to be performed. In this paper, we present a new passive valve structure for a capillary driven microfluidic device. It is a variation of a capillary trigger valve that is amenable to silicon microfabrication; it will be referred to as a stair-step liquid triggered valve. In this paper, the valve functionality and its dependencies on channel geometry, surface contact angle, and surface roughness are studied both experimentally and with numerical modeling. The effect of the contact angle was explored in experiments on the silicon microfabricated valve structure; a maximal working contact angle, above which the valve fails to be triggered, was demonstrated. The fluidic behavior in the stair-step channel structure was further explored computationally using the finite volume method with the volume-of-fluid approach. Surface roughness due to scalloping of the sidewall during the Bosch etch process was hypothesized to reduce the sidewall contact angle. The reduced contact angle has considerable impacts on the capillary pressure as the liquid vapor interface traverses the stair-step structure of the valve. An improved match in the maximal working contact angle between the experiments and model was obtained when considering this surface roughness effect.

Interfacial spreading effects on one-dimensional organic liquid imbibition in water-wetted porous media

NASA Astrophysics Data System (ADS)

McBride, J. F.; Simmons, C. S.; Cary, J. W.

1992-10-01

The spreading coefficient, Csp, determines whether an organic immiscible liquid, OIL, will form a lens ( Csp < 0) or will spread spontaneously ( Csp > 0) on a water surface. An OIL that forms a lens does not perfectly wet the water surface and therefore has a contact angle greater than 0°. The one-dimensional rate at which an OIL spreads spontaneously on a water surface is proportional to the square root of Csp. Of the OIL's that pose a contaminant threat to the subsurface, the majority has a non-zero Csp. To test the influence of such interfacial spreading phenomena on OIL infiltration in a pristine vadose zone, upward OIL and water imbibition infiltration experiments were performed in glass-bead columns, moistened with water, by using OIL's with different Csp. An analytical model for saturated liquid front rise was used to inversely estimate the effective capillary pressure head at the front and the average liquid conductivity. A nonspreading OIL ( Csp ≪ 0) exhibited a reduced capillary pressure head in the water-wetted glass beads. A spontaneously spreading OIL ( Csp ≫0) manifested an enhanced capillary pressure head. Reduced capillary pressure head was associated with an increase in average conductivity, and enhanced capillary pressure head was associated with a decrease in average conductivity when compared to the average water conductivity during water imbibition. The employed experimental method and mathematical analysis of dynamic flow, subject to interfacial spreading phenomena, are practical for quantifying parameters for use in sharp-front OIL infiltration models, but more research is needed to determine how to incorporate the spreading coefficient in numerical multiphase flow models.

Flexible waveguides for IR laser radiation and surgery applications.

PubMed

Gannot, I; Dror, J; Calderon, S; Kaplan, I; Croitoru, N

1994-01-01

Flexible plastic waveguides were developed to deliver IR radiation, especially at 10.6 microns, which is the CO2 laser radiation wavelength. The waveguide is made from teflon tube with the inner wall coated with a metal layer and a dielectric overlayer. The internal diameter (ID) is 1.0 mm, length 1.0-1.2 m, and the distal tip decreases moderately to ID approximately 0.6 mm. The distal part on the last 10 centimeters is coated externally with a metal layer. Maximum power that can be delivered at the outlet is approximately 30 W and 10.6 x 10(3) W/cm2. This type of waveguide was used in several medical operations to evaluate its cutting characteristics and the resistances to heat reflection from the tissue while operating in orifices containing liquid substances.

Wideband Waveguide Acousto-Optic Bragg Cell.

DTIC Science & Technology

The results of an effort to improve the performance specifications of acousto - optic Bragg cells are reported. Various configurations of multiple...would provide a 700 MHz acousto - optic bandwidth. Investigated were Bragg cells fabricated on Ti diffused LiNb03 waveguides as well as Ti diffused LiNb03

Flow Modification Induced by Quincke Rotation in a Capillary

NASA Astrophysics Data System (ADS)

Cebers, A.; Lemaire, E.; Lobry, L.

When particles immersed in a semi-insulating liquid are submitted to a sufficiently high DC field, they can rotate spontaneously around any axis perpendicular to the field (Quincke rotation). Recently we have shown that due to Quincke effect the effective viscosity of a colloidal suspension could be reduced. When the suspension is submitted to a shear, the particles rotation is amplified by the electric torque and drives the suspending liquid. For a flow in a capillary, this effect manifests itself by an increase of the flow rate. We present the results of our experiments carried out with a rectangular cross section capillary. These results are compared with the direct determination of the apparent viscosity in a Couette flow rheometer.

Implementation of high slurry concentration and sonication to pack high-efficiency, meter-long capillary ultrahigh pressure liquid chromatography columns.

PubMed

Godinho, Justin M; Reising, Arved E; Tallarek, Ulrich; Jorgenson, James W

2016-09-02

Slurry packing capillary columns for ultrahigh pressure liquid chromatography is complicated by many interdependent experimental variables. Previous results have suggested that combination of high slurry concentration and sonication during packing would create homogeneous bed microstructures and yield highly efficient capillary columns. Herein, the effect of sonication while packing very high slurry concentrations is presented. A series of six, 1m×75μm internal diameter columns were packed with 200mg/mL slurries of 2.02μm bridged-ethyl hybrid silica particles. Three of the columns underwent sonication during packing and yielded highly efficient separations with reduced plate heights as low as 1.05. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization of passive polymer optical waveguides

NASA Astrophysics Data System (ADS)

Joehnck, Matthias; Kalveram, Stefan; Lehmacher, Stefan; Pompe, Guido; Rudolph, Stefan; Neyer, Andreas; Hofstraat, Johannes W.

1999-05-01

The characterization of monomode passive polymer optical devices fabricated according to the POPCORN technology by methods originated from electron, ion and optical spectroscopy is summarized. Impacts of observed waveguide perturbations on the optical characteristics of the waveguide are evaluated. In the POPCORN approach optical components for telecommunication applications are fabricated by photo-curing of liquid halogenated (meth)acrylates which have been applied on moulded thermoplastic substrates. For tuning of waveguide material refractive indices with respect to the substrate refractive index frequently comonomer mixtures are used. The polymerization characteristics, especially the polymerization kinetics of individual monomers, determine the formation of copolymers. Therefore the unsaturation as function of UV-illumination time in the formation of halogenated homo- and copolymers has been examined. From different suitable copolymer system, after characterization of their glass transition temperatures, their curing behavior and their refractive indices as function of the monomer ratios, monomode waveguides applying PMMA substrates have been fabricated. To examine the materials composition also in the 6 X 6 micrometers 2 waveguides they have been visualized by transmission electron microscopy. With this method e.g. segregation phenomena could be observed in the waveguide cross section characterization as well. The optical losses in monomode waveguides caused by segregation and other materials induce defects like micro bubbles formed as a result of shrinkage have been quantized by return loss measurements. Defects causing scattering could be observed by convocal laser scanning microscopy and by conventional light microscopy.

Fingering and Intermittent Flow in Unsaturated Fractured Porous Media

NASA Astrophysics Data System (ADS)

Or, D.; Ghezzehei, T. A.

2003-12-01

Because of the dominance of gravitational forces over capillary and viscous forces in relatively large fracture apertures, flow processes in unsaturated fractures are considerably different from flow in rock matrix or in unsaturated soils. Additionally, variations in fracture geometry and properties perturb the delicate balance between gravitational, capillary, and viscous forces, leading to liquid fragmentation, fingering and intermittent flows. We developed a quantitative framework for modeling fluid fragmentation and the subsequent flow behavior of discrete fluid elements (slugs). The transition from a slowly growing but stationary liquid cluster to a finger-forming mobile slug in a non horizontal fracture is estimated from the force balance between retarding capillary forces dominated by contact angle hysteresis, and the weight and shape of the cluster. For a steady flux we developed a model for liquid fragmentation within the fracture plane that gives rise to intermittent discharge, as has been observed experimentally. Intermittency is shown to be a result of interplay between capillary, viscous, and gravitational forces, much like internal dripping. Liquid slug size, detachment interval, and travel velocity are dependent primarily on the local fracture-aperture geometry shaping the seed cluster, rock-surface roughness and wetness, and liquid flux feeding the bridge (either by film flow or from the rock matrix). We show that the presence of even a few irregularities in a vertical fracture surface could affect liquid cluster formation and growth, resulting in complicated flux patterns at the fracture bottom. Such chaotic-like behavior has been observed in previous studies involving gravity-driven unsaturated flow. Inferences based on statistical description of fracture-aperture variations and simplified representation of the fragmentation processes yield insights regarding magnitude and frequency of liquid avalanches. The study illustrates that attempts at describing intermittent and preferential flow behavior by adjustment of macroscopic continuum approaches are destined to failure at most local scales. In accordance with recent observations, flow behavior in partially saturated fractures tends to produce highly localize pathways that focus otherwise diffusive fluxes (film flow or matrix seepage).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiratsuka, Tatsumasa; Tanaka, Hideki, E-mail: tanaka@cheme.kyoto-u.ac.jp; Miyahara, Minoru T., E-mail: miyahara@cheme.kyoto-u.ac.jp

Capillary condensation in the regime of developing hysteresis occurs at a vapor pressure, P{sub cond}, that is less than that of the vapor-like spinodal. This is because the energy barrier for the vapor-liquid transition from a metastable state at P{sub cond} becomes equal to the energy fluctuation of the system; however, a detailed mechanism of the spontaneous transition has not been acquired even through extensive experimental and simulation studies. We therefore construct accurate atomistic silica mesopore models for MCM-41 and perform molecular simulations (gauge cell Monte Carlo and grand canonical Monte Carlo) for argon adsorption on the models at subcriticalmore » temperatures. A careful comparison between the simulation and experiment reveals that the energy barrier for the capillary condensation has a critical dimensionless value, W{sub c}{sup *} = 0.175, which corresponds to the thermal fluctuation of the system and depends neither on the mesopore size nor on the temperature. We show that the critical energy barrier W{sub c}{sup *} controls the capillary condensation pressure P{sub cond} and also determines a boundary between the reversible condensation/evaporation regime and the developing hysteresis regime.« less

Determining CDOM Absorption Spectra in Diverse Aquatic Environments Using a Multiple Pathlength, Liquid Core Waveguide System

NASA Technical Reports Server (NTRS)

Miller, Richard L.; Belz, Mathias; DelCastillo, Carlos; Trzaska, Rick

2001-01-01

We evaluated the accuracy, sensitivity and precision of a multiple pathlength, liquid core waveguide (MPLCW) system for measuring colored dissolved organic matter (CDOM) absorption in the UV-visible spectral range (370-700 nm). The MPLCW has four optical paths (2.0, 9.8, 49.3, and 204 cm) coupled to a single Teflon AF sample cell. Water samples were obtained from inland, coastal and ocean waters ranging in salinity from 0 to 36 PSU. Reference solutions for the MPLCW were made having a refractive index of the sample. CDOM absorption coefficients, aCDOM, and the slope of the log-linearized absorption spectra, S, were compared with values obtained using a dual-beam spectrophotometer. Absorption of phenol red secondary standards measured by the MPLCW at 558 nm were highly correlated with spectrophotometer values and showed a linear response across all four pathlengths. Values of aCDOM measured using the MPLCW were virtually identical to spectrophotometer values over a wide range of concentrations. The dynamic range of aCDOM for MPLCW measurements was 0.002 - 231.5 m-1. At low CDOM concentrations spectrophotometric aCDOM were slightly greater than MPLCW values and showed larger fluctuations at longer wavelengths due to limitations in instrument precision. In contrast, MPLCW spectra followed an exponential to 600 nm for all samples.

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. Copyright © 2016 the American Physiological Society.

Mid-IR absorption sensing of heavy water using a silicon-on-sapphire waveguide.

PubMed

Singh, Neetesh; Casas-Bedoya, Alvaro; Hudson, Darren D; Read, Andrew; Mägi, Eric; Eggleton, Benjamin J

2016-12-15

We demonstrate a compact silicon-on-sapphire (SOS) strip waveguide sensor for mid-IR absorption spectroscopy. This device can be used for gas and liquid sensing, especially to detect chemically similar molecules and precisely characterize extremely absorptive liquids that are difficult to detect by conventional infrared transmission techniques. We reliably measure concentrations up to 0.25% of heavy water (D₂O) in a D₂O-H₂O mixture at its maximum absorption band at around 4 μm. This complementary metal-oxide-semiconductor (CMOS) compatible SOS D₂O sensor is promising for applications such as measuring body fat content or detection of coolant leakage in nuclear reactors.

Optical waveguide loop for planar trapping of blood cells and microspheres

NASA Astrophysics Data System (ADS)

Ahluwalia, Balpreet S.; Hellesø, Olav G.

2013-09-01

The evanescent field from a waveguide can be used to trap and propel a particle. An optical waveguide loop with an intentional gap at the center is used for planar transport and stable trapping of particles. The waveguide acts as a conveyor belt to trap and deliver spheres towards the gap. At the gap, the counter-diverging light fields hold the sphere at a fixed position. Numerical simulation based on the finite element method was performed in three dimensions using a computer cluster. The field distribution and optical forces for rib and strip waveguide designs are compared and discussed. The optical force on a single particle was computed for various positions of the particle in the gap. Simulation predicted stable trapping of particles in the gap. Depending on the gap separation (2-50 μm) a single or multiple spheres and red blood cells were trapped at the gap. Waveguides were made of tantalum pentaoxide material. The waveguides are only 180 nm thick and thus could be integrated with other functions on the chip.

Isolation of a single rice chromosome by optical micromanipulation

NASA Astrophysics Data System (ADS)

Wang, Haowei; Liu, Xiaohui; Li, Yinmei; Han, Bin; Lou, Liren; Wang, Kangjun

2004-01-01

A new method based on optical tweezers technology is reported for the isolation of a single chromosome. A rice cell suspended in liquid was first fragmented by laser pulses (optical scalpel). Then a single released chromosome from the cell was manipulated and pulled away from other cells and oddments by optical tweezers without any direct mechanical contact. Finally the isolated single chromosome was extracted individually into a glass capillary nearby. After molecular cloning of the isolated chromosome, we obtained some specific DNA segments from the single chromosome. All these segments can be used for rice genomic sequencing. Different methods of extracting a single chromosome are compared. The advantages of optical micromanipulation method are summarized.

Study of liquid and vapor flow into a Centaur capillary device

NASA Technical Reports Server (NTRS)

Blatt, M. H.; Risberg, J. A.

1979-01-01

The following areas of liquid and vapor flow were analyzed and experimentally evaluated; 1) the refilling of capillary devices with settled liquid, and 2) vapor flow across wetted screens. These investigations resulted in: 1) the development of a versatile computer program that was successfully correlated with test data and used to predict Centaur D-1S LO2 and LH2 start basket refilling; 2) the development of a semi-empirical model that was only partially correlated with data due to difficulties in obtaining repeatable test results. Also, a comparison was made to determine the best propellant management system for the Centaur D-1S vehicle. The comparison identified the basline Centaur D-1S system (using pressurization, boost pumps and propellant settling) as the best candidate based on payload weight penalty. However, other comparison criteria and advanced mission condition were identified where pressure fed systems, thermally subcooled boost pumps and capillary devices would be selected as attractive alternatives.

Capillary evaporation of the ionic liquid [EMIM][BF4] in nanoscale solvophobic confinement

NASA Astrophysics Data System (ADS)

Shrivastav, Gourav; Remsing, Richard C.; Kashyap, Hemant K.

2018-05-01

Solvent density fluctuations play a crucial role in liquid-vapor transitions in solvophobic confinement and can also be important for understanding solvation of polar and apolar solutes. In the case of ionic liquids (ILs), density fluctuations can be used to understand important processes in the context of nanoscale aggregation and colloidal self-assemblies. In this article, we explore the nature of density fluctuations associated with capillary evaporation of the IL 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) in the confined region of model solvophobic nanoscale sheets by using molecular dynamics simulations combined with non-Boltzmann sampling techniques. We demonstrate that density fluctuations of the confined IL play an important role in capillary evaporation, suggesting analogies to dewetting transitions involving water. Significant changes in the interfacial structure of the IL are also detailed and suggested to underlie a non-classical (non-parabolic) dependence of the free energy barrier to evaporation on the degree of confinement.

Hollow-fiber liquid-phase microextraction coupled with miniature capillary electrophoresis for the trace analysis of four aliphatic aldehydes in water samples.

PubMed

Li, Ying; Yi, Fan; Zheng, Yiliang; Wang, Yu; Ye, Jiannong; Chu, Qingcui

2015-08-01

An environmentally friendly method for the trace analysis of four aliphatic aldehydes as water disinfection byproducts has been developed based on hollow-fiber liquid-phase microextraction followed by miniature capillary electrophoresis with amperometric detection. After derivatization with 2-thiobarbituric acid, four aliphatic aldehydes (formaldehyde, acetaldehyde, propylaldehyde, and butyraldehyde) became detectable by the amperometric detector. Under the optimum conditions, four aliphatic aldehydes can be well separated from the coexisting interferents as well as their homologs (pentanal, glyoxal, and methyl-glyoxal), and the limits of detection (S/N = 3) could reach sub-nanogram-per-milliliter level based on hollow-fiber liquid-phase microextraction. The proposed method has been applied for the analyses of above four aliphatic aldehydes in different water samples such as drinking water, tap water, and river water, and the average recoveries were in the range of 90-113%, providing an alternative to conventional and microchip capillary electrophoresis approaches. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Altshuler, Gennady; Manor, Ofer, E-mail: manoro@technion.ac.il

A MHz vibration, or an acoustic wave, propagating in a solid substrate may support the convective spreading of a liquid film. Previous studies uncovered this ability for fully wetting silicon oil films under the excitation of a MHz Rayleigh surface acoustic wave (SAW), propagating in a lithium niobate substrate. Partially wetting de-ionized water films, however, appeared immune to this spreading mechanism. Here, we use both theory and experiment to reconsider this situation and show partially wetting water films may spread under the influence of a propagating MHz vibration. We demonstrate distinct capillary and convective (vibrational/acoustic) spreading regimes that are governedmore » by a balance between convective and capillary mechanisms, manifested in the non-dimensional number θ{sup 3}/We, where θ is the three phase contact angle of the liquid with the solid substrate and We ≡ ρU{sup 2}H/γ; ρ, γ, H, and U are the liquid density, liquid/vapour surface tension, characteristic film thickness, and the characteristic velocity amplitude of the propagating vibration on the solid surface, respectively. Our main finding is that the vibration will support a continuous spreading motion of the liquid film out of a large reservoir if the convective mechanism prevails (θ{sup 3}/We < 1); otherwise (θ{sup 3}/We > 1), the dynamics of the film is governed by the capillary mechanism.« less

Inkjet Printing of Functional Materials for Optical and Photonic Applications

PubMed Central

Alamán, Jorge; Alicante, Raquel; Peña, Jose Ignacio; Sánchez-Somolinos, Carlos

2016-01-01

Inkjet printing, traditionally used in graphics, has been widely investigated as a valuable tool in the preparation of functional surfaces and devices. This review focuses on the use of inkjet printing technology for the manufacturing of different optical elements and photonic devices. The presented overview mainly surveys work done in the fabrication of micro-optical components such as microlenses, waveguides and integrated lasers; the manufacturing of large area light emitting diodes displays, liquid crystal displays and solar cells; as well as the preparation of liquid crystal and colloidal crystal based photonic devices working as lasers or optical sensors. Special emphasis is placed on reviewing the materials employed as well as in the relevance of inkjet in the manufacturing of the different devices showing in each of the revised technologies, main achievements, applications and challenges. PMID:28774032

Solid-liquid interfacial free energy of ice Ih, ice Ic, and ice 0 within a mono-atomic model of water via the capillary wave method.

PubMed

Ambler, Michael; Vorselaars, Bart; Allen, Michael P; Quigley, David

2017-02-21

We apply the capillary wave method, based on measurements of fluctuations in a ribbon-like interfacial geometry, to determine the solid-liquid interfacial free energy for both polytypes of ice I and the recently proposed ice 0 within a mono-atomic model of water. We discuss various choices for the molecular order parameter, which distinguishes solid from liquid, and demonstrate the influence of this choice on the interfacial stiffness. We quantify the influence of discretisation error when sampling the interfacial profile and the limits on accuracy imposed by the assumption of quasi one-dimensional geometry. The interfacial free energies of the two ice I polytypes are indistinguishable to within achievable statistical error and the small ambiguity which arises from the choice of order parameter. In the case of ice 0, we find that the large surface unit cell for low index interfaces constrains the width of the interfacial ribbon such that the accuracy of results is reduced. Nevertheless, we establish that the interfacial free energy of ice 0 at its melting temperature is similar to that of ice I under the same conditions. The rationality of a core-shell model for the nucleation of ice I within ice 0 is questioned within the context of our results.

Design of Capillary Flows with Spatially Graded Porous Films

NASA Astrophysics Data System (ADS)

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

2013-11-01

We have developed a new capillary tube model, consisting of multi-layered capillary tubes oriented in the direction of flow, to predict capillary speeds on spatially graded porous films. Capillary flows through thin porous media have been widely utilized for small size liquid transport systems. However, for most media it is challenging to realize arbitrary shapes and spatially functionalized micro-structures with variable flow properties. Therefore, conventional media can only be used for capillary flows obeying Washburn's equation and the modifications thereof. Given this background, we recently developed a method called breakdown anodization (BDA) to produce highly wetting porous films. The resulting surfaces show nearly zero contact angles and fast water spreading speed. Furthermore, capillary pressure and spreading diffusivity can be expressed as functions of capillary height when customized electric fields are used in BDA. From the capillary tube model, we derived a general capillary flow equation of motion in terms of capillary pressure and spreading diffusivity. The theoretical model shows good agreement with experimental capillary flows. The study will provide novel design methodologies for paper-based microfluidic devices.

Aqueous carrier waveguide in a flow cytometer

DOEpatents

Mariella, R.P. Jr.; Engh, G. van den; Northrup, M.A.

1995-12-12

The liquid of a flow cytometer itself acts as an optical waveguide, thus transmitting the light to an optical filter/detector combination. This alternative apparatus and method for detecting scattered light in a flow cytometer is provided by a device which views and detects the light trapped within the optical waveguide formed by the flow stream. A fiber optic or other light collecting device is positioned within the flow stream. This provides enormous advantages over the standard light collection technique which uses a microscope objective. The signal-to-noise ratio is greatly increased over that for right-angle-scattered light collected by a microscope objective, and the alignment requirements are simplified. 6 figs.

Generation of capillary instabilities by external disturbances in a liquid jet. Ph.D. Thesis - State Univ. of N.Y.

NASA Technical Reports Server (NTRS)

Leib, S. J.

1985-01-01

The receptivity problem in a circular liquid jet is considered. A time harmonic axial pressure gradient is imposed on the steady, parallel flow of a jet of liquid emerging from a circular duct. Using a technique developed in plasma physics a casual solution to the forced problem is obtained over certain ranges of Weber number for a number of mean velocity profiles. This solution contains a term which grows exponentially in the downstream direction and can be identified with a capillary instability wave. Hence, it is found that the externally imposed disturbances can indeed trigger instability waves in a liquid jet. The amplitude of the instability wave generated relative to the amplitude of the forcing is computed numerically for a number of cases.

CFE-2 Experiment Run

NASA Image and Video Library

2013-11-21

View of Flight Engineer (FE) Koichi Wakata posing for a photo during a CFE-2 (Capillary Flow Experiment - 2) Interior Corner Flow - 8 (ICF-8) test run. Liquids behave differently in space than they do on Earth, so containers that can process, hold or transport them must be designed carefully to work in microgravity. The Capillary Flow Experiment-2 furthers research on wetting, which is a liquid's ability to spread across a surface, and its impact over large length scales in strange container shapes in microgravity environments. This work will improve capabilities to quickly and accurately predict how related processes occur, and allow us to design better systems to process liquids aboard spacecraft (i.e., liquid fuel tanks, thermals fluids, and water processing for life support). Image was released by astronaut on Twitter.

Construction of stable capillary networks using a microfluidic device.

PubMed

Sudo, Ryo

2015-01-01

Construction of stable capillary networks is required to provide sufficient oxygen and nutrients to the deep region of thick tissues, which is important in the context of 3D tissue engineering. Although conventional in vitro culture models have been used to investigate the mechanism of capillary formation, recent advances in microfluidics technologies allowed us to control biophysical and biochemical culture environments more precisely, which led to the construction of functional and stable capillary networks. In this study, endothelial cells and mesenchymal stem cells were co-cultured in microfluidic devices to construct stable capillary networks, which resulted in the construction of luminal structures covered by pericytes. Interactions between endothelial cells and mesenchymal stem cells are also discussed in the context of capillary formation.

Suppressing Crack Formation in Particulate Systems by Utilizing Capillary Forces

PubMed Central

Schneider, Monica; Maurath, Johannes; Fischer, Steffen B.; Weiß, Moritz; Willenbacher, Norbert; Koos, Erin

2017-01-01

Cracks, formed during the drying of particulate films, can reduce the effectiveness or even render products useless. We present a novel, generic approach to suppress crack formation in thin films made from hard particle suspensions, which are otherwise highly susceptible to cracking, using the capillary force between particles present when a trace amount of an immiscible liquid is added to a suspension. This secondary liquid preserves the particle cohesion, modifying the structure and increasing the drying rate. Crack-free films can be produced at thicknesses much greater than the critical cracking thickness for a suspension without capillary interactions, and even persists after sintering. This capillary suspension strategy is applicable to a broad range of materials including suspensions of metals, semiconductive and ceramic oxides or glassy polymeric particles and can be easily implemented in many industrial processes since it is based on well-established unit operations. Promising fields of application include ceramic foils and printed electronic devices. PMID:28263554

A Novel Device Addressing Design Challenges for Passive Fluid Phase Separations Aboard Spacecraft

NASA Astrophysics Data System (ADS)

Weislogel, M. M.; Thomas, E. A.; Graf, J. C.

2009-07-01

Capillary solutions have long existed for the control of liquid inventories in spacecraft fluid systems such as liquid propellants, cryogens and thermal fluids for temperature control. Such large length scale, `low-gravity,' capillary systems exploit container geometry and fluid properties—primarily wetting—to passively locate or transport fluids to desired positions for a variety of purposes. Such methods have only been confidently established if the wetting conditions are known and favorable. In this paper, several of the significant challenges for `capillary solutions' to low-gravity multiphase fluids management aboard spacecraft are briefly reviewed in light of applications common to life support systems that emphasize the impact of the widely varying wetting properties typical of aqueous systems. A restrictive though no less typifying example of passive phase separation in a urine collection system is highlighted that identifies key design considerations potentially met by predominately capillary solutions. Sample results from novel scale model prototype testing aboard a NASA low-g aircraft are presented that support the various design considerations.

Methods of forming and using porous structures for energy efficient separation of light gases by capillary condensation

DOEpatents

Calamur, Narasimhan; Carrera, Martin E.; Devlin, David J.; Archuleta, Tom

2000-01-01

The present invention relates to an improved method and apparatus for separating one or more condensable compounds from a mixture of two or more gases of differing volatilities by capillary fractionation in a membrane-type apparatus, and a method of forming porous structures therefor. More particularly, the invention includes methods of forming and using an apparatus consisting, at least in part, of a porous structure having capillary-type passages extending between a plurality of small openings on the first side and larger openings on a second side of the structure, the passages being adapted to permit a condensed liquid to flow therethrough substantially by capillary forces, whereby vapors from the mixture are condensed, at least in part, and substantially in and adjacent to the openings on the first side, and are caused to flow in a condensed liquid state, substantially in the absence of vapor, from the openings on the first side to the openings on the second side.

Dynamic behaviors of liquid droplets on a gas diffusion layer surface: Hybrid lattice Boltzmann investigation

NASA Astrophysics Data System (ADS)

Wu, Jie; Huang, Jun-Jie

2015-07-01

Water management is one of the key issues in proton exchange membrane fuel cells. Fundamentally, it is related to dynamic behaviors of droplets on a gas diffusion layer (GDL) surface, and consequently they are investigated in this work. A two-dimensional hybrid method is employed to implement numerical simulations, in which the flow field is solved by using the lattice Boltzmann method and the interface between droplet and gas is captured by solving the Cahn-Hilliard equation directly. One or two liquid droplets are initially placed on the GDL surface of a gas channel, which is driven by the fully developed Poiseuille flow. At a fixed channel size, the effects of viscosity ratio of droplet to gas ( μ ∗ ), Capillary number (Ca, ratio of gas viscosity to surface tension), and droplet interaction on the dynamic behaviors of droplets are systematically studied. By decreasing viscosity ratio or increasing Capillary number, the single droplet can detach from the GDL surface easily. On the other hand, when two identical droplets stay close to each other or a larger droplet is placed in front of a smaller droplet, the removal of two droplets is promoted.

Target molecules detection by waveguiding in a photonic silicon membrane

DOEpatents

Letant, Sonia E [Livermore, CA; Van Buuren, Anthony [Livermore, CA; Terminello, Louis [Danville, CA; Hart, Bradley R [Brentwood, CA

2006-12-26

Disclosed herein is a porous silicon filter capable of binding and detecting biological and chemical target molecules in liquid or gas samples. A photonic waveguiding silicon filter with chemical and/or biological anchors covalently attached to the pore walls bind target molecules. The system uses transmission curve engineering principles to allow measurements to be made in situ and in real time to detect the presence of various target molecules and calculate the concentration of bound target.

Target molecules detection by waveguiding in a photonic silicon membrane

DOEpatents

Letant, Sonia; Van Buuren, Anthony; Terminello, Louis

2004-08-31

Disclosed herein is a photonic silicon filter capable of binding and detecting biological and chemical target molecules in liquid or gas samples. A photonic waveguiding silicon filter with chemical and/or biological anchors covalently attached to the pore walls selectively bind target molecules. The system uses transmission curve engineering principles to allow measurements to be made in situ and in real time to detect the presence of various target molecules and determine the concentration of bound target.

Surface Deformation by Thermo-capillary Convection -Sounding Rocket COMPERE Experiment SOURCE

NASA Astrophysics Data System (ADS)

Fuhrmann, Eckart; Dreyer, Michael E.

The sounding rocket COMPERE experiment SOURCE was successfully flown on MASER 11, launched in Kiruna (ESRANGE), May 15th, 2008. SOURCE has been intended to partly ful-fill the scientific objectives of the European Space Agency (ESA) Microgravity Applications Program (MAP) project AO-2004-111 (Convective boiling and condensation). Three parties of principle investigators have been involved to design the experiment set-up: ZARM for thermo-capillary flows, IMFT (Toulouse, France) for boiling studies, EADS Astrium (Bremen, Ger-many) for depressurization. The scientific aims are to study the effect of wall heat flux on the contact line of the free liquid surface and to obtain a correlation for a convective heat transfer coefficient. The experiment has been conducted along a predefined time line. A preheating sequence at ground was the first operation to achieve a well defined temperature evolution within the test cell and its environment inside the rocket. Nearly one minute after launch, the pressurized test cell was filled with the test liquid HFE-7000 until a certain fill level was reached. Then the free surface could be observed for 120 s without distortion. Afterwards, the first depressurization was started to induce subcooled boiling, the second one to start saturated boiling. The data from the flight consists of video images and temperature measurements in the liquid, the solid, and the gaseous phase. Data analysis provides the surface shape versus time and the corresponding apparent contact angle. Computational analysis provides information for the determination of the heat transfer coefficient in a compensated gravity environment where a flow is caused by the temperature difference between the hot wall and the cold liquid. Correlations for the effective contact angle and the heat transfer coefficient shall be delivered as a function of the relevant dimensionsless parameters. The data will be used for benchmarking of commercial CFD codes and the tank design (using these codes) of future cryogenic upper stages.

Ultrasonic technique for monitoring of liquid density variations

NASA Astrophysics Data System (ADS)

Kazys, R.; Rekuviene, R.; Sliteris, R.; Mazeika, L.; Zukauskas, E.

2015-01-01

A novel ultrasonic measurement technique for density measurements of different liquids in extreme conditions has been developed. The proposed density measurement method is based on transformation of the acoustic impedance of the measured liquid. The higher accuracy of measurements is achieved by means of the λ/4 acoustic matching layer between the load and the ultrasonic waveguide transducer. Introduction of the matching layer enhances sensitivity of the measurement system. Sometimes, the density measurements must be performed in very complex conditions: high temperature (up to 200 °C), pressure (up to 10 MPa), and high chemical activity of the medium under measurement. In this case, the special geometry metal waveguides are proposed to use in order to protect the piezoelectric transducer surface from influence of a high temperature. The experimental set-up of technique was calibrated using the reference liquids with different densities: ethyl ether, ethyl alcohol, distilled water, and different concentration (20%, 40%, and 60%) sugar-water solutions. The uncertainty of measurements is less than 1%. The proposed measurement method was verified in real conditions by monitoring the density of a melted polypropylene during manufacturing process.

Planar optical waveguide based sandwich assay sensors and processes for the detection of biological targets including protein markers, pathogens and cellular debris

DOEpatents

Martinez, Jennifer S [Santa Fe, NM; Swanson, Basil I [Los Alamos, NM; Grace, Karen M [Los Alamos, NM; Grace, Wynne K [Los Alamos, NM; Shreve, Andrew P [Santa Fe, NM

2009-06-02

An assay element is described including recognition ligands bound to a film on a single mode planar optical waveguide, the film from the group of a membrane, a polymerized bilayer membrane, and a self-assembled monolayer containing polyethylene glycol or polypropylene glycol groups therein and an assay process for detecting the presence of a biological target is described including injecting a biological target-containing sample into a sensor cell including the assay element, with the recognition ligands adapted for binding to selected biological targets, maintaining the sample within the sensor cell for time sufficient for binding to occur between selected biological targets within the sample and the recognition ligands, injecting a solution including a reporter ligand into the sensor cell; and, interrogating the sample within the sensor cell with excitation light from the waveguide, the excitation light provided by an evanescent field of the single mode penetrating into the biological target-containing sample to a distance of less than about 200 nanometers from the waveguide thereby exciting the fluorescent-label in any bound reporter ligand within a distance of less than about 200 nanometers from the waveguide and resulting in a detectable signal.

Planar optical waveguide based sandwich assay sensors and processes for the detection of biological targets including early detection of cancers

DOEpatents

Martinez, Jennifer S [Santa Fe, NM; Swanson, Basil I [Los Alamos, NM; Shively, John E [Arcadia, CA; Li, Lin [Monrovia, CA

2009-06-02

An assay element is described including recognition ligands adapted for binding to carcinoembryonic antigen (CEA) bound to a film on a single mode planar optical waveguide, the film from the group of a membrane, a polymerized bilayer membrane, and a self-assembled monolayer containing polyethylene glycol or polypropylene glycol groups therein and an assay process for detecting the presence of CEA is described including injecting a possible CEA-containing sample into a sensor cell including the assay element, maintaining the sample within the sensor cell for time sufficient for binding to occur between CEA present within the sample and the recognition ligands, injecting a solution including a reporter ligand into the sensor cell; and, interrogating the sample within the sensor cell with excitation light from the waveguide, the excitation light provided by an evanescent field of the single mode penetrating into the biological target-containing sample to a distance of less than about 200 nanometers from the waveguide thereby exciting any bound reporter ligand within a distance of less than about 200 nanometers from the waveguide and resulting in a detectable signal.

Temperature-Modulated Array High-Performance Liquid Chromatography

PubMed Central

Premstaller, Andreas; Xiao, Wenzhong; Oberacher, Herbert; O'Keefe, Matthew; Stern, David; Willis, Thomas; Huber, Christian G.; Oefner, Peter J.

2001-01-01

Using novel monolithic poly(styrene-divinylbenzene) capillary columns with an internal diameter of 0.2 mm, we demonstrate for the first time the feasibility of constructing high-performance liquid chromatography arrays for the detection of mutations by heteroduplex analysis under partially denaturing conditions. In one embodiment, such an array can be used to analyze one sample simultaneously at different temperatures to maximize the detection of mutations in DNA fragments containing multiple discrete melting domains. Alternatively, one may inject different samples onto columns kept at the same effective temperature. Further improvements in throughput can be obtained by means of laser-induced fluorescence detection and the differential labeling of samples with up to four different fluorophores. Major advantages of monolithic capillary high-performance liquid chromatographic arrays over their capillary electrophoretic analogs are the chemical inertness of the poly(styrene-divinylbenzene) stationary phase, the physical robustness of the column bed due to its covalent linkage to the inner surface of the fused silica capillary, and the feasibility to modify the stationary phase thereby allowing the separation of compounds not only on the principle of size exclusion, but also adsorption, distribution, and ion exchange. Analyses times are on the order of a few minutes and turnaround time is extremely short as there is no need for the replenishment of the separation matrix between runs. PMID:11691859

From catastrophic acceleration to deceleration of liquid plugs in prewetted capillary tubes

NASA Astrophysics Data System (ADS)

Magniez, Juan; Baudoin, Michael; Zoueshtiagh, Farzam; Lemac/Lics Team

2016-11-01

Liquid/gas flows in capillaries are involved in a multitude of systems including flow in porous media, petroleum extraction, imbibition of paper or flows in pulmonary airways in pathological conditions. Liquid plugs, witch compose the biphasic flows, can have a dramatic impact on patients with pulmonary obstructive diseases, since they considerably alter the circulation of air in the airways and thus can lead to severe breathing difficulties. Here, the dynamics of liquid plugs in prewetted capillary tube is investigated experimentally and theoretically, with a particular emphasis on the role of the prewetting films and of the driving condition (constant flow rate, constant pressure). For both driving conditions, the plugs can either experience a continuous increase or decrease of their size. While this phenomenon is regular in the case of imposed flow rate, a constant pressure head can lead to a catastrophic acceleration of the plug and eventually its rupture or a dramatic increase of the plug size. A theoretical model is proposed to explain the transition between theses two regimes. These results give a new insight on the critical pressure required for airways obstruction and reopening. IEMN, International Laboratory LEMAC/LICS, UMR CNRS 8520, University of Lille.

Thermo-capillary effect on the linear temporal and spatial instability of viscous liquid jets falling under gravity

NASA Astrophysics Data System (ADS)

Alsharif, Abdullah M.; Althubaiti, Shadiah A.

2018-03-01

The thermal modulation of Newtonian liquid jets at the orifice causes a variation in surface tension, which propagates downstream inducing Marangoni instability. Therefore, the linear temporal and spatial instability should be investigated to predict the same size of producing small spherical pellets. In this paper, we consider a viscous liquid jet emerging from a nozzle subject to thermo-capillary effects falling under gravity. Moreover, we use the asymptotic approach to reduce the governing equation into one-dimensional (1-D). The steady state solutions have been found using a modified Newton's method, and then the linear instability analysis has been investigated of the resulting set of equations.

Numerical analysis of cell adhesion in capillary flow

NASA Astrophysics Data System (ADS)

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

2016-11-01

Numerical simulation of cell adhesion was performed for capillaries whose diameter is comparable to or smaller than that of the cell. Despite a lot of works about leukocyte and tumor cell rolling, cell motion in capillaries has remained unclear. 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 is obtained for various values of capillary diameter and receptor density. According to our numerical results, 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 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. This research was supported by JSPS KAKENHI Grant Numbers 25000008, 26107703, 14J03967. We also acknowledge support from the Tohoku University Division for International Advanced Research and Education Organization.

MRI investigation of water-oil two phase flow in straight capillary, bifurcate channel and monolayered glass bead pack.

PubMed

Liu, Yu; Jiang, Lanlan; Zhu, Ningjun; Zhao, Yuechao; Zhang, Yi; Wang, Dayong; Yang, Mingjun; Zhao, Jiafei; Song, Yongchen

2015-09-01

The study of immiscible fluid displacement between aqueous-phase liquids and non-aqueous-phase liquids in porous media is of great importance to oil recovery, groundwater contamination, and underground pollutant migration. Moreover, the attendant viscous, capillary, and gravitational forces are essential to describing the two-phase flows. In this study, magnetic resonance imaging was used to experimentally examine the detailed effects of the viscous, capillary, and gravitational forces on water-oil flows through a vertical straight capillary, bifurcate channel, and monolayered glass-bead pack. Water flooding experiments were performed at atmospheric pressure and 37.8°C, and the evolution of the distribution and saturation of the oil as well as the characteristics of the two-phase flow were investigated and analyzed. The results showed that the flow paths, i.e., the fingers of the displacing phase, during the immiscible displacement in the porous medium were determined by the viscous, capillary, and gravitational forces as well as the sizes of the pores and throats. The experimental results afford a fundamental understanding of immiscible fluid displacement in a porous medium. Copyright © 2015 Elsevier Inc. All rights reserved.

Freeze-tolerant condenser for a closed-loop heat-transfer system

NASA Technical Reports Server (NTRS)

Crowley, Christopher J. (Inventor); Elkouh, Nabil A. (Inventor)

2002-01-01

A freeze tolerant condenser (106) for a two-phase heat transfer system is disclosed. The condenser includes an enclosure (110) and a porous artery (112) located within and extending along the length of the enclosure. A vapor space (116) is defined between the enclosure and the artery, and a liquid space (114) is defined by a central passageway within the artery. The artery includes a plurality of laser-micromachined capillaries (130) extending from the outer surface of the artery to its inner surface such that the vapor space is in fluid communication with the liquid space. In one embodiment of the invention, the capillaries (130) are cylindrical holes having a diameter of no greater than 50 microns. In another embodiment, the capillaries (130') are slots having widths of no greater than 50 microns. A method of making an artery in accordance with the present invention is also disclosed. The method includes providing a solid-walled tube and laser-micromachining a plurality of capillaries into the tube along a longitudinal axis, wherein each capillary has at least one cross-sectional dimension transverse to the longitudinal axis of less than 50 microns.

Reactor for in situ measurements of spatially resolved kinetic data in heterogeneous catalysis

NASA Astrophysics Data System (ADS)

Horn, R.; Korup, O.; Geske, M.; Zavyalova, U.; Oprea, I.; Schlögl, R.

2010-06-01

The present work describes a reactor that allows in situ measurements of spatially resolved kinetic data in heterogeneous catalysis. The reactor design allows measurements up to temperatures of 1300 °C and 45 bar pressure, i.e., conditions of industrial relevance. The reactor involves reactants flowing through a solid catalyst bed containing a sampling capillary with a side sampling orifice through which a small fraction of the reacting fluid (gas or liquid) is transferred into an analytical device (e.g., mass spectrometer, gas chromatograph, high pressure liquid chromatograph) for quantitative analysis. The sampling capillary can be moved with μm resolution in or against flow direction to measure species profiles through the catalyst bed. Rotation of the sampling capillary allows averaging over several scan lines. The position of the sampling orifice is such that the capillary channel through the catalyst bed remains always occupied by the capillary preventing flow disturbance and fluid bypassing. The second function of the sampling capillary is to provide a well which can accommodate temperature probes such as a thermocouple or a pyrometer fiber. If a thermocouple is inserted in the sampling capillary and aligned with the sampling orifice fluid temperature profiles can be measured. A pyrometer fiber can be used to measure the temperature profile of the solid catalyst bed. Spatial profile measurements are demonstrated for methane oxidation on Pt and methane oxidative coupling on Li/MgO, both catalysts supported on reticulated α -Al2O3 foam supports.

Thermal Blood Clot Formation and use in Microfluidic Device Valving Applications

NASA Technical Reports Server (NTRS)

Tai, Yu-Chong (Inventor); Shi, Wendian (Inventor); Guo, Luke (Inventor)

2014-01-01

The present invention provides a method of forming a blood-clot microvalve by heating blood in a capillary tube of a microfluidic device. Also described are methods of modulating liquid flow in a capillary tube by forming and removing a blood-clot microvalve.

Implementation of serial amplifying fluorescent polymer arrays for enhanced chemical vapor sensing of landmines

NASA Astrophysics Data System (ADS)

Fisher, Mark E.; la Grone, Marcus; Sikes, John

2003-09-01

A sensor (known as Fido) that utilizes amplification of fluorescence quenching as the transduction mechanism for ultra-trace detection of nitroaromatic compounds associated with landmines has been described previously. Previous sensor prototypes utilized a single band of amplifying polymer deployed inside a capillary waveguide to form the sensing element of the detector. A new prototype has been developed that incorporates multiple, discrete bands of different amplifying polymers deployed in a linear array inside the capillary. Vapor-phase samples are introduced into the sensor as a sharp pulse via a gated inlet. As the vapor pulse is swept through the capillary by flow of a carrier gas, the pulse of analyte encounters the bands of polymer sequentially. If the sample contains nitroaromatic explosives, the bands of polymer will respond with a reduction in emission intensity proportional to the mass of analyte in the sample. Because the polymer bands are deployed serially, the analyte pulse does not reach the bands of polymer simultaneously. Hence, a temporal response pattern will be observed as the analyte pulse traverses the length of the capillary. In addition, the intensity of response for each band will vary, producing a ratiometric response. The temporal and ratiometric responses are characteristic of a given analyte, enhancing discrimination of target analytes from potential interferents. This should translate into a reduction in sensor false alarm rates.

Automatic cryogenic liquid level controller is safe for use near combustible substances

NASA Technical Reports Server (NTRS)

Krejsa, M.

1966-01-01

Automatic mechanical liquid level controller that is independent of any external power sources is used with safety in the presence of combustibles. A gas filled capillary tube which leads from a pressurized chamber, is inserted into the cryogenic liquid reservoir and becomes a liquid level sensing element or probe.

ZnO nanotube waveguide arrays on graphene films for local optical excitation on biological cells

NASA Astrophysics Data System (ADS)

Baek, Hyeonjun; Kwak, Hankyul; Song, Minho S.; Ha, Go Eun; Park, Jongwoo; Tchoe, Youngbin; Hyun, Jerome K.; Park, Hye Yoon; Cheong, Eunji; Yi, Gyu-Chul

2017-04-01

We report on scalable and position-controlled optical nanoprobe arrays using ZnO nanotube waveguides on graphene films for use in local optical excitation. For the waveguide fabrication, position-controlled and well-ordered ZnO nanotube arrays were grown on chemical vapor deposited graphene films with a submicron patterned mask layer and Au prepared between the interspace of nanotubes. Mammalian cells were cultured on the nanotube waveguide arrays and were locally excited by light illuminated through the nanotubes. Fluorescence and optogenetic signals could be excited through the optical nanoprobes. This method offers the ability to investigate cellular behavior with a high spatial resolution that surpasses the current limitation.

Vibration isolation technology: Sensitivity of selected classes of space experiments to residual accelerations

NASA Technical Reports Server (NTRS)

Alexander, J. Iwan D.; Zhang, Y. Q.; Adebiyi, Adebimpe

1989-01-01

Progress performed on each task is described. Order of magnitude analyses related to liquid zone sensitivity and thermo-capillary flow sensitivity are covered. Progress with numerical models of the sensitivity of isothermal liquid zones is described. Progress towards a numerical model of coupled buoyancy-driven and thermo-capillary convection experiments is also described. Interaction with NASA personnel is covered. Results to date are summarized and they are discussed in terms of the predicted space station acceleration environment. Work planned for the second year is also discussed.

CSE-MECC two-dimensional capillary electrophoresis analysis of proteins in the mouse tumor cell (AtT-20) homogenate

PubMed Central

Chen, Xingguo; Fazal, Md. Abul; Dovichi, Norman J.

2007-01-01

Two-dimensional capillary electrophoresis was used for the separation of proteins and biogenic amines from the mouse AtT-20 cell line. The first-dimension capillary contained a TRIS-CHES-SDS-dextran buffer to perform capillary sieving electrophoresis, which is based on molecular weight of proteins. The second-dimension capillary contained a TRIS-CHES-SDS buffer for micel1ar electrokinetic capillary chromatography. After a 61 seconds preliminary separation, fractions from the first-dimension capillary were successively transferred to the second-dimension capillary, where they further separated by MECC. The two-dimensional separation required 60 minutes. PMID:17637850

Mid-infrared refractive index sensing using optimized slotted photonic crystal waveguides

NASA Astrophysics Data System (ADS)

Kassa-Baghdouche, Lazhar; Cassan, Eric

2018-02-01

Slotted photonic crystal waveguides (SPCWs) were designed to act as refractive index sensing devices at mid-infrared (IR) wavelengths around λ = 3.6 μm. In particular, effort was made to engineer the input and output slot waveguide interfaces in order to increase the effective sensitivity through resonant tapering. A slotted PhC waveguide immersed in air and liquid cladding layers was considered. To determine the performance of the sensor, the sensitivity of the device was estimated by calculating the shift in the upper band edge of the output transmission spectrum. The results showed that the sensitivity of a conventionally designed SPCW followed by modifications in the structure parameter yielded a 510 nm shift in the wavelength position of the upper band edge, indicating a sensitivity of more than 1150 nm per refractive index unit (RIU) with an insertion loss level of -0.3 dB. This work demonstrates the viability of photonic crystal waveguide high sensitivity devices in the Mid-IR, following a transposition of the concepts inherited from the telecom band and an optimization of the design, in particular a minimization of photonic device insertion losses.

The interface of an array of five capillaries with an array of one-nanoliter wells for high-resolution electrophoretic analysis as an approach to high-throughput chemical cytometry

PubMed Central

Boardman, Anna; McQuaide, Sarah C.; Zhu, Cuiru; Whitmore, Colin; Lidstrom, Mary E.; Dovichi, Norman J.

2009-01-01

We report a system that allows the simultaneous aspiration of one or more cells into each of five capillaries for electrophoresis analysis. A glass wafer was etched to create an array of 1 nL wells. The glass was treated with poly(2-hydroxyethyl methacrylate) to control cell adherence. A suspension of formalin-fixed cells was placed on the surface, and cells were allowed to settle. The concentration of cells and the settling time were chosen so that there was, on average, one cell per well. Next, an array of five capillaries was placed so that the tip of each capillary was in contact with a single well. A pulse of vacuum was applied to the distal end of the capillaries to aspirate the content of each well into a capillary. Next, the tips of the capillaries were placed in running buffer and potential was applied. The cells lysed upon contact with the running buffer, and fluorescent components were detected at the distal end of the capillaries by laser-induced fluorescence. The electrophoretic separation efficiency was outstanding, generating over 750,000 theoretical plates (1,800,000 plates/meter). In this example, AtT-20 cells were used that had been treated with TMR-GM1. The cells were allowed to metabolize this substrate into a series of products before the cells were fixed. The number of cells found in each well was estimated visually under the microscope and was described by a Poisson distribution with mean of 0.95 cells/well. This system provides an approach to high-throughput chemical cytometry. PMID:18717573

Fiber optic-based regenerable biosensor

DOEpatents

Sepaniak, Michael J.; Vo-Dinh, Tuan

1993-01-01

A fiber optic-based regenerable biosensor. The biosensor is particularly suitable for use in microscale work in situ. In one embodiment, the biosensor comprises a reaction chamber disposed adjacent the distal end of a waveguide and adapted to receive therein a quantity of a sample containing an analyte. Leading into the chamber is a plurality of capillary conduits suitable for introducing into the chamber antibodies or other reagents suitable for selective interaction with a predetermined analyte. Following such interaction, the contents of the chamber may be subjected to an incident energy signal for developing fluorescence within the chamber that is detectable via the optical fiber and which is representative of the presence, i.e. concentration, of the selected analyte. Regeneration of the biosensor is accomplished by replacement of the reagents and/or the analyte, or a combination of these, at least in part via one or more of the capillary conduits. The capillary conduits extend from their respective terminal ends that are in fluid communication with the chamber, away from the chamber to respective location(s) remote from the chamber thereby permitting in situ location of the chamber and remote manipulation and/or analysis of the activity with the chamber.

Photovoltaic modules with cylindrical waveguides in a system for the secondary concentration of solar radiation

NASA Astrophysics Data System (ADS)

Andreev, V. M.; Davidyuk, N. Yu.; Ionova, E. A.; Rumyantsev, V. D.

2013-09-01

The parameters of the concentrating photoelectric modules with triple-junction (InGaP/GaAs/Ge) solar cells whose focusing system contains an original secondary optical element are studied. The element consists of a plane-convex lens in optical contact with the front surface of an intermediate glass plate and a cylindrical waveguide that is located on the rear side of the glass plate above the surface of the solar element. It is demonstrated that the structure of the secondary optical element provides a wide misorientation characteristic of the concentrator and the cylindrical waveguide allows a more uniform radiation density over the surface of the solar cell. The effect of chromatic aberration in the primary and secondary optical systems on the parameters of photoelectric modules is analyzed. It is demonstrated that the presence of waveguides with a length of 3-5 mm leads to effective redistribution of radiation over the surface of the solar cell whereas shorter and longer waveguides provide the local concentration of radiation at the center of the photodetecting area.

Capillary wave theory of adsorbed liquid films and the structure of the liquid-vapor interface

NASA Astrophysics Data System (ADS)

MacDowell, Luis G.

2017-08-01

In this paper we try to work out in detail the implications of a microscopic theory for capillary waves under the assumption that the density is given along lines normal to the interface. Within this approximation, which may be justified in terms of symmetry arguments, the Fisk-Widom scaling of the density profile holds for frozen realizations of the interface profile. Upon thermal averaging of capillary wave fluctuations, the resulting density profile yields results consistent with renormalization group calculations in the one-loop approximation. The thermal average over capillary waves may be expressed in terms of a modified convolution approximation where normals to the interface are Gaussian distributed. In the absence of an external field we show that the phenomenological density profile applied to the square-gradient free energy functional recovers the capillary wave Hamiltonian exactly. We extend the theory to the case of liquid films adsorbed on a substrate. For systems with short-range forces, we recover an effective interface Hamiltonian with a film height dependent surface tension that stems from the distortion of the liquid-vapor interface by the substrate, in agreement with the Fisher-Jin theory of short-range wetting. In the presence of long-range interactions, the surface tension picks up an explicit dependence on the external field and recovers the wave vector dependent logarithmic contribution observed by Napiorkowski and Dietrich. Using an error function for the intrinsic density profile, we obtain closed expressions for the surface tension and the interface width. We show the external field contribution to the surface tension may be given in terms of the film's disjoining pressure. From literature values of the Hamaker constant, it is found that the fluid-substrate forces may be able to double the surface tension for films in the nanometer range. The film height dependence of the surface tension described here is in full agreement with results of the capillary wave spectrum obtained recently in computer simulations, and the predicted translation mode of surface fluctuations reproduces to linear order in field strength an exact solution of the density correlation function for the Landau-Ginzburg-Wilson Hamiltonian in an external field.

Axisymmetric Liquid Hanging Drops

ERIC Educational Resources Information Center

Meister, Erich C.; Latychevskaia, Tatiana Yu

2006-01-01

The geometry of drops hanging on a circular capillary can be determined by numerically solving a dimensionless differential equation that is independent on any material properties, which enables one to follow the change of the height, surface area, and contact angle of drops hanging on a particular capillary. The results show that the application…

All-optical Integrated Switches Based on Azo-benzene Liquid Crystals on Silicon

DTIC Science & Technology

2011-11-01

Glass D263 SU8 Polymer Polymer NLC n̂ n̂ Refractive index @1.55 µm Materials n// = 1.689 n⊥= 1.502 n = 1.575 n = 1.516 E7 Glass D263 SU8 ...In the other case we have a nonlinear LCW based on glass substrates. It consists in a rectangular hollow realized in SU8 photoresist two glass...and discussion 5. All optical polymeric waveguide: methods, assumptions and procedure 6. All optical polymeric waveguide: results and discussion 7

Hydraulic conductivity of variably saturated porous media: Film and corner flow in angular pore space

NASA Astrophysics Data System (ADS)

Tuller, Markus; Or, Dani

2001-05-01

Many models for hydraulic conductivity of partially saturated porous media rely on oversimplified representation of the pore space as a bundle of cylindrical capillaries and disregard flow in liquid films. Recent progress in modeling liquid behavior in angular pores of partially saturated porous media offers an alternative framework. We assume that equilibrium liquid-vapor interfaces provide well-defined and stable boundaries for slow laminar film and corner flow regimes in pore space comprised of angular pores connected to slit-shaped spaces. Knowledge of liquid configuration in the assumed geometry facilitates calculation of average liquid velocities in films and corners and enables derivation of pore-scale hydraulic conductivity as a function of matric potential. The pore-scale model is statistically upscaled to represent hydraulic conductivity for a sample of porous medium. Model parameters for the analytical sample-scale expressions are estimated from measured liquid retention data and other measurable medium properties. Model calculations illustrate the important role of film flow, whose contribution dominates capillary flow (in full pores and corners) at relatively high matric potentials (approximately -100 to -300 J kg-1, or -1 to 3 bars). The crossover region between film and capillary flow is marked by a significant change in the slope of the hydraulic conductivity function as often observed in measurements. Model predictions are compared with the widely applied van Genuchten-Mualem model and yield reasonable agreement with measured retention and hydraulic conductivity data over a wide range of soil textural classes.

Role of capillary electrophoresis in the fight against doping in sports.

PubMed

Harrison, Christopher R

2013-08-06

At present the role of capillary electrophoresis in the detection of doping agents in athletes is, for the most part, nonexistent. More traditional techniques, namely gas and liquid chromatography with mass spectrometric detection, remain the gold standard of antidoping tests. This Feature will investigate the in-roads that capillary electrophoresis has made, the limitations that the technique suffers from, and where the technique may grow into being a key tool for antidoping analysis.

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.

Multiphase Transport in Porous Media: Gas-Liquid Separation Using Capillary Pressure Gradients International Space Station (ISS) Flight Experiment Development

NASA Technical Reports Server (NTRS)

Wheeler, Richard R., Jr.; Holtsnider, John T.; Dahl, Roger W.; Deeks, Dalton; Javanovic, Goran N.; Parker, James M.; Ehlert, Jim

2013-01-01

Advances in the understanding of multiphase flow characteristics under variable gravity conditions will ultimately lead to improved and as of yet unknown process designs for advanced space missions. Such novel processes will be of paramount importance to the success of future manned space exploration as we venture into our solar system and beyond. In addition, because of the ubiquitous nature and vital importance of biological and environmental processes involving airwater mixtures, knowledge gained about fundamental interactions and the governing properties of these mixtures will clearly benefit the quality of life here on our home planet. The techniques addressed in the current research involving multiphase transport in porous media and gas-liquid phase separation using capillary pressure gradients are also a logical candidate for a future International Space Station (ISS) flight experiment. Importantly, the novel and potentially very accurate Lattice-Boltzmann (LB) modeling of multiphase transport in porous media developed in this work offers significantly improved predictions of real world fluid physics phenomena, thereby promoting advanced process designs for both space and terrestrial applications.This 3-year research effort has culminated in the design and testing of a zero-g demonstration prototype. Both the hydrophilic (glass) and hydrophobic (Teflon) media Capillary Pressure Gradient (CPG) cartridges prepared during the second years work were evaluated. Results obtained from ground testing at 1-g were compared to those obtained at reduced gravities spanning Martian (13-g), Lunar (16-g) and zero-g. These comparisons clearly demonstrate the relative strength of the CPG phenomena and the efficacy of its application to meet NASAs unique gas-liquid separation (GLS) requirements in non-terrestrial environments.LB modeling software, developed concurrently with the zero-g test effort, was shown to accurately reproduce observed CPG driven gas-liquid separation phenomena. The design and fabrication of a micropost plate-lamina Hele-Shaw (HS) cell was performed which served as a computationally attainable geometric structure facilitating direct comparison between physical phenomena observed in our laboratory and the LB software predictions.

Herpin effective media resonant underlayers and resonant overlayer designs for ultra-high NA interference lithography.

PubMed

Bourke, Levi; Blaikie, Richard J

2017-12-01

Dielectric waveguide resonant underlayers are employed in ultra-high NA interference photolithography to effectively double the depth of field. Generally a single high refractive index waveguiding layer is employed. Here multilayer Herpin effective medium methods are explored to develop equivalent multilayer waveguiding layers. Herpin equivalent resonant underlayers are shown to be suitable replacements provided at least one layer within the Herpin trilayer supports propagating fields. In addition, a method of increasing the intensity incident upon the photoresist using resonant overlayers is also developed. This method is shown to greatly enhance the intensity within the photoresist making the use of thicker, safer, non-absorbing, low refractive index matching liquids potentially suitable for large-scale applications.

Method of fabricating optical waveguides by ion implantation doping

DOEpatents

Appleton, B.R.; Ashley, P.R.; Buchal, C.J.

1987-03-24

A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO/sub 3/ crystals are implanted with high concentrations of Ti dopant at ion energies of about 360 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000/degree/C produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguiding properties.

Fast Electrically Driven Capillary Rise Using Overdrive Voltage.

PubMed

Hong, Sung Jin; Hong, Jiwoo; Seo, Hee Won; Lee, Sang Joon; Chung, Sang Kug

2015-12-29

Enhancement of response speed (or reduction of response time) is crucial for the commercialization of devices based on electrowetting (EW), such as liquid lenses and reflective displays, and presents one of the main challenges in EW research studies. We demonstrate here that an overdrive EW actuation gives rise to a faster rise of a liquid column between parallel electrodes, compared to a DC EW actuation. Here, DC actuation is actually a simple applied step function, and overdrive is an applied step followed by reduction to a lower voltage. Transient behaviors and response time (i.e., the time required to reach the equilibrium height) of the rising liquid column are explored under different DC and overdrive EW actuations. When the liquid column rises up to a target height by means of an overdrive EW, the response time is reduced to as low as 1/6 of the response time using DC EW. We develop a theoretical model to simulate the EW-driven capillary rise by combining the kinetic equation of capillary flow (i.e., Lucas-Washburn equation) and the dynamic contact angle model considering contact line friction, contact angle hysteresis, contact angle saturation, and the EW effect. This theoretical model accurately predicts the outcome to within a ± 5% error in regard to the rising behaviors of the liquid column with a low viscosity, under both DC EW and overdrive actuation conditions, except for the early stage (

Design of five-layer gold nanoparticles self-assembled in a liquid open tubular column for ultrasensitive nano-LC-MS/MS proteomic analysis of 80 living cells.

PubMed

Shao, Xi; Zhang, Xiangmin

2017-04-01

In this work, for the first time, a liquid open tubular column modified by five-layer gold nanoparticles and linked with C 18 (GNPs@C 18 ) was designed and fabricated for nano-LC-MS/MS analysis of 80 living cells. Sixty nanometer gold nanoparticles were self-assembled layer by layer on the inner wall of a 20 μm id fused-silica capillary. C 18 was then linked on the gold nanoparticles to make the liquid open tubular column show hydrophobic character. Enough loading capacities for analysis of 80 living cells, ∼100 fmol for pk-10 and ∼30 fmol for insulin, were obtained with the 2 m × 20 μm id five-layer GNPs@C 18 open tubular column. The open tubular column was used in an online pretreatment and direct nano-LC-MS/MS analysis system to analyze 80 living HepG2 cells. In total, 650 proteins were identified in triplicate runs. The subcellular localization of the identified proteins showed that our system had no bias toward different cellular compartments. Protein copy number per cell of the identified proteins showed that the detection limit could reach 50 zmol and the abundance of the identified proteins could cover a dynamic range of 6 orders. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Interfacial waves generated by contact line motion through electrowetting

NASA Astrophysics Data System (ADS)

Ha, Jonghyun; Park, Jaebum; Kim, Yunhee; Bae, Jungmok; Kim, Ho-Young

2013-11-01

The contact angle of a liquid-fluid interface can be effectively modulated by EWOD (electrowetting on dielectric). Rapid movement of the contact line, which can be achieved by swift change of voltages at the electrodes, can give rise to interfacial waves under the strong influence of surface tension. Many optofluidic devices employing EWOD actuation, such as lenses, three-dimensional displays and laser radar, use two different liquids in a single cell, implying that the motions of the two liquids should be considered simultaneously to solve the dynamics of interfacial waves. Furthermore, the capillary waves excited by moving contact lines, which inherently involve slipping flows at solid boundaries, pose an interesting problem that has not been treated so far. We perform a perturbation analysis for this novel wave system to find the dispersion relation that relates the wavenumber, and the decay length over which the wave is dissipated by viscous effects. We experimentally corroborate our theory.

Low-Loss Coupling of Quantum Cascade Lasers into Hollow-Core Waveguides with Single-Mode Output in the 3.7–7.6 μm Spectral Range

PubMed Central

Patimisco, Pietro; Sampaolo, Angelo; Mihai, Laura; Giglio, Marilena; Kriesel, Jason; Sporea, Dan; Scamarcio, Gaetano; Tittel, Frank K.; Spagnolo, Vincenzo

2016-01-01

We demonstrated low-loss and single-mode laser beam delivery through hollow-core waveguides (HCWs) operating in the 3.7–7.6 μm spectral range. The employed HCWs have a circular cross section with a bore diameter of 200 μm and metallic/dielectric internal coatings deposited inside a glass capillary tube. The internal coatings have been produced to enhance the spectral response of the HCWs in the range 3.5–12 µm. We demonstrated Gaussian-like outputs throughout the 4.5–7.6 µm spectral range. A quasi single-mode output beam with only small beam distortions was achieved when the wavelength was reduced to 3.7 μm. With a 15-cm-long HCW and optimized coupling conditions, we measured coupling efficiencies of >88% and transmission losses of <1 dB in the investigated infrared spectral range. PMID:27089343

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.

Capillary channel flow experiments aboard the International Space Station

NASA Astrophysics Data System (ADS)

Conrath, M.; Canfield, P. J.; Bronowicki, P. M.; Dreyer, M. E.; Weislogel, M. M.; Grah, A.

2013-12-01

In the near-weightless environment of orbiting spacecraft capillary forces dominate interfacial flow phenomena over unearthly large length scales. In current experiments aboard the International Space Station, partially open channels are being investigated to determine critical flow rate-limiting conditions above which the free surface collapses ingesting bubbles. Without the natural passive phase separating qualities of buoyancy, such ingested bubbles can in turn wreak havoc on the fluid transport systems of spacecraft. The flow channels under investigation represent geometric families of conduits with applications to liquid propellant acquisition, thermal fluids circulation, and water processing for life support. Present and near future experiments focus on transient phenomena and conduit asymmetries allowing capillary forces to replace the role of gravity to perform passive phase separations. Terrestrial applications are noted where enhanced transport via direct liquid-gas contact is desired.

Capillary liquid chromatography-microchip atmospheric pressure chemical ionization-mass spectrometry.

PubMed

Ostman, Pekka; Jäntti, Sirkku; Grigoras, Kestas; Saarela, Ville; Ketola, Raimo A; Franssila, Sami; Kotiaho, Tapio; Kostiainen, Risto

2006-07-01

A miniaturized nebulizer chip for capillary liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (capillary LC-microchip APCI-MS) is presented. The APCI chip consists of two wafers, a silicon wafer and a Pyrex glass wafer. The silicon wafer has a DRIE etched through-wafer nebulizer gas inlet, an edge capillary insertion channel, a stopper, a vaporizer channel and a nozzle. The platinum heater electrode and pads for electrical connection were patterned on to the Pyrex glass wafer. The two wafers were joined by anodic bonding, creating a microchip version of an APCI-source. The sample inlet capillary from an LC column is directly connected to the vaporizer channel of the APCI chip. The etched nozzle in the microchip forms a narrow sample plume, which is ionized by an external corona needle, and the formed ions are analyzed by a mass spectrometer. The nebulizer chip enables for the first time the use of low flow rate separation techniques with APCI-MS. The performance of capillary LC-microchip APCI-MS was tested with selected neurosteroids. The capillary LC-microchip APCI-MS provides quantitative repeatability and good linearity. The limits of detection (LOD) with a signal-to-noise ratio (S/N) of 3 in MS/MS mode for the selected neurosteroids were 20-1000 fmol (10-500 nmol l(-1)). LODs (S/N = 3) with commercial macro APCI with the same compounds using the same MS were about 10 times higher. Fast heat transfer allows the use of the optimized temperature for each compound during an LC run. The microchip APCI-source provides a convenient and easy method to combine capillary LC to any API-MS equipped with an APCI source. The advantages and potentials of the microchip APCI also make it a very attractive interface in microfluidic APCI-MS.

Intrinsic advantages of packed capillaries over narrow-bore columns in very high-pressure gradient liquid chromatography.

PubMed

Gritti, Fabrice; McDonald, Thomas; Gilar, Martin

2016-06-17

250μm×100mm fused silica glass capillaries were packed with 1.8μm high-strength silica (HSS) fully porous particles. They were prepared without bulky stainless steel endfittings and metal frits, which both generate significant sample dispersion. The isocratic efficiencies and gradient peak capacities of these prototype capillary columns were measured for small molecules (n-alkanophenones) using a home-made ultra-low dispersive micro-HPLC instrument. Their resolution power was compared to that of standard 2.1mm×100mm very high-pressure liquid chromatography (vHPLC) narrow-bore columns packed with the same particles. The results show that, for the same column efficiency (25000 plates) and gradient steepness (0.04min(-1)), the peak capacity of the 250μm i.d. capillary columns is systematically 15-20% higher than that of the 2.1mm i.d. narrow-bore columns. A validated model of gradient chromatography enabled one to predict accurately the observed peak capacities of the capillary columns for non-linear solvation strength retention behavior and under isothermal conditions. Thermodynamics applied to the eluent quantified the temperature difference for the thermal gradients in both capillary and narrow-bore columns. Experimental data revealed that the gradient peak capacity is more affected by viscous heating than the column efficiency. Unlike across 2.1mm i.d. columns, the changes in eluent composition across the 250μm i.d. columns during the gradient is rapidly relaxed by transverse dispersion. The combination of (1) the absence of viscous heating and (2) the high uniformity of the eluent composition across the diameter of capillary columns explains the intrinsic advantage of capillary over narrow-bore columns in gradient vHPLC. Copyright © 2016 Elsevier B.V. All rights reserved.

Scaling law on formation and rupture of a dynamical liquid bridge

NASA Astrophysics Data System (ADS)

Zhang, Huang; Zhang, Zehao; Liu, Qianfeng; Li, Shuiqing; Department of Thermal Engineering, Tsinghua University Collaboration; Institute of Nuclear Energy; Technology, Tsinghua University Collaboration

2017-11-01

The formation and breakup of a pendular liquid bridge in dynamic state is investigated experimentally. The experimental setup arises from a system to measure the coefficient of restitution (COR) of a glass sphere impacting and bouncing on a wetted surface. We compare the effect of surface tension and gravity on the liquid bridge rupture by the capillary length κ-1. For water and liquid 1 (50% water mixed with 50% glycerol), the gravity is dominant on the liquid bridge breakup. And we find that the rupture distance is in good linear trend with the non-dimensional number G by the scaling law analysis. Further, for liquid 2 (25% water mixed with 75% glycerol) that is relatively high viscous, the linear changing of the rupture distance with the capillary number Ca is found. The relation of the rupture distance with G and Ca would be helpful in understanding the complex behavior of the dynamical liquid bridge. This work was funded by the Major State Basic Research Development Program of China (Grant No. 2016YFC0203705) and the China Postdoctoral Science Foundation (Grant No. 2016M601024).

Simulation of water vapor condensation on LOX droplet surface using liquid nitrogen

NASA Technical Reports Server (NTRS)

Powell, Eugene A.

1988-01-01

The formation of ice or water layers on liquid oxygen (LOX) droplets in the Space Shuttle Main Engine (SSME) environment was investigated. Formulation of such ice/water layers is indicated by phase-equilibrium considerations under conditions of high partial pressure of water vapor (steam) and low LOX droplet temperature prevailing in the SSME preburner or main chamber. An experimental investigation was begun using liquid nitrogen as a LOX simulant. A monodisperse liquid nitrogen droplet generator was developed which uses an acoustic driver to force the stream of liquid emerging from a capillary tube to break up into a stream of regularly space uniformly sized spherical droplets. The atmospheric pressure liquid nitrogen in the droplet generator reservoir was cooled below its boiling point to prevent two phase flow from occurring in the capillary tube. An existing steam chamber was modified for injection of liquid nitrogen droplets into atmospheric pressure superheated steam. The droplets were imaged using a stroboscopic video system and a laser shadowgraphy system. Several tests were conducted in which liquid nitrogen droplets were injected into the steam chamber. Under conditions of periodic droplet formation, images of 600 micron diameter liquid nitrogen droplets were obtained with the stroboscopic video systems.

Demonstration of Nautilus Centripetal Capillary Condenser Technology

NASA Technical Reports Server (NTRS)

Wheeler, RIchard; Tang, Linh; Wambolt, Spencer; Golliher, Eric; Agui, Juan

2016-01-01

This paper describes the results of a proof of concept effort for development of a Nautilus Centripetal Capillary Condenser (NCCC or NC3) used for microgravity compatible water recovery from moist air with integral passive phase separation. Removal of liquid condensate from the air stream exiting a condenser is readily performed here on Earth. In order to perform this function in space however, without gravity or mechanical action, other tactics including utilization of inertial, drag and capillary forces are required. Within the NC3, liquid water forms via condensation on cold condenser surfaces as humid air passes along multiple spiral channels, each in its own plane, all together forming a stacked plate assembly. Non-mechanical inertial forces are employed to transfer condensate, as it forms, via centripetal action to the outer perimeter of each channel. A V-shaped groove, constructed on this outer edge of the spiral channel, increases local capillary forces thereby retaining the liquid. Air drag then pulls the liquid along to a collection region near the center of the device. Dry air produced by each parallel spiral channel is combined in a common orthogonal, out-of-plane conduit passing down the axial center of the stacked device. Similarly, the parallel condensate streams are combined and removed from the condenser/separator through yet another out-of-plane axial conduit. NC3 is an integration of conventional finned condenser operation, combined with static phase separation and capillary transport phenomena. A Mars' transit mission would be a logical application for this technology where gravity is absent and the use of vibrating, energy-intensive, motor-driven centrifugal separators is undesired. Here a vapor stream from either the Heat Melt Compactor or the Carbon dioxide Reduction Assembly, for example, would be dried to a dew point of 10 deg using a passive NC3 condenser/separator with the precious water condensate recycled to the water bus.

Liquid core photonic crystal fiber with low-refractive-index liquids for optofluidic applications.

PubMed

Park, Jiyoung; Kang, Doo-Eui; Paulson, Bjorn; Nazari, Tavakol; Oh, Kyunghwan

2014-07-14

A defectless hexagonal air-silica photonic crystal fiber (PCF) structure with its central hole selectively filled by a low-refractive-index liquid is numerically analyzed. Despite the fact that the refractive index of the liquid is significantly lower than that of silica, we found an optimal range of waveguide parameters to ensure light guidance through the liquid core in the fundamental mode, maximizing the light-liquid interaction over a desired wavelength range. Using the vectorial finite element method (FEM), we report detailed parametric studies in terms of the effective index, chromatic dispersion, optical loss, and modal intensity distribution of the liquid core PCFs.

Geometry-induced phase transition in fluids: Capillary prewetting

NASA Astrophysics Data System (ADS)

Yatsyshin, Petr; Savva, Nikos; Kalliadasis, Serafim

2013-02-01

We report a new first-order phase transition preceding capillary condensation and corresponding to the discontinuous formation of a curved liquid meniscus. Using a mean-field microscopic approach based on the density functional theory we compute the complete phase diagram of a prototypical two-dimensional system exhibiting capillary condensation, namely that of a fluid with long-ranged dispersion intermolecular forces which is spatially confined by a substrate forming a semi-infinite rectangular pore exerting long-ranged dispersion forces on the fluid. In the T-μ plane the phase line of the new transition is tangential to the capillary condensation line at the capillary wetting temperature Tcw. The surface phase behavior of the system maps to planar wetting with the phase line of the new transition, termed capillary prewetting, mapping to the planar prewetting line. If capillary condensation is approached isothermally with T>Tcw, the meniscus forms at the capping wall and unbinds continuously, making capillary condensation a second-order phenomenon. We compute the corresponding critical exponent for the divergence of adsorption.

1 K cryostat with sub-millikelvin stability based on a pulse-tube cryocooler

NASA Astrophysics Data System (ADS)

DeMann, A.; Mueller, Sara; Field, S. B.

2016-01-01

A cryogenic system has been designed and tested that reaches a temperature below 1.1 K, with an rms temperature stability of 25 μ K. In this system a commercial pulse-tube cryocooler is used to liquify helium gas supplied from an external source. This liquid helium enters a 1 K pot through a large-impedance capillary tube, similar to a conventional 1 K system operated from a liquid helium bath. Unlike a conventional system, however, the molar flow rate of the system can be varied by changing the pressure of the incoming helium. This allows for a trade-off between helium usage and cooling power, which has a maximum value of 27 mW. The measured cooling power and fraction of helium exiting the capillary as liquid agree well with predictions based on an isenthalpic model of helium flow through the capillary. The system is simple to use and inexpensive to operate: The system can be cooled to base temperature in about 3 h and, with a flow rate giving a cooling power of 13 mW, the helium cost is around 6 per day.

Interfacial layering and capillary roughness in immiscible liquids.

PubMed

Geysermans, P; Pontikis, V

2010-08-21

The capillary roughness and the atomic density profiles of extended interfaces between immiscible liquids are determined as a function of the interface area by using molecular dynamics and Lennard-Jones (12-6) potentials. We found that with increasing area, the interface roughness diverges logarithmically, thus fitting the theoretical mean-field prediction. In systems small enough for the interfacial roughness not to blur the structural details, atomic density profiles across the fluid interface are layered with correlation length in the range of molecular correlations in liquids. On increasing the system size, the amplitude of the thermally excited position fluctuations of the interface increases, thus causing layering to rapidly vanish, if density profiles are computed without special care. In this work, we present and validate a simple method, operating in the direct space, for extracting from molecular dynamics trajectories the "intrinsic" structure of a fluid interface that is the local density profile of the interface cleaned from capillary wave effects. Estimated values of interfacial properties such as the tension, the intrinsic width, and the lower wavelength limit of position fluctuations are in agreement with results collected from the literature.

Capillary waves and the decay of density correlations at liquid surfaces

NASA Astrophysics Data System (ADS)

Hernández-Muñoz, Jose; Chacón, Enrique; Tarazona, Pedro

2016-12-01

Wertheim predicted strong density-density correlations at free liquid surfaces, produced by capillary wave fluctuations of the interface [M. S. Wertheim, J. Chem. Phys. 65, 2377 (1976), 10.1063/1.433352]. That prediction has been used to search for a link between capillary wave (CW) theory and density functional (DF) formalism for classical fluids. In particular, Parry et al. have recently analyzed the decaying tails of these CW effects moving away from the interface as a clue for the extended CW theory [A. O. Parry et al., J. Phys.: Condens. Matter 28, 244013 (2016), 10.1088/0953-8984/28/24/244013], beyond the strict long-wavelength limit studied by Wertheim. Some apparently fundamental inconsistencies between the CW and the DF theoretical views of the fluid interfaces arose from the asymptotic analysis of the CW signal. In this paper we revisit the problem of the CW asymptotic decay with a separation of local non-CW surface correlation effects from those that are a truly nonlocal propagation of the CW fluctuations from the surface towards the liquid bulk.

Analysis of microdialysate monoamines, including noradrenaline, dopamine and serotonin, using capillary ultra-high performance liquid chromatography and electrochemical detection.

PubMed

Ferry, Barbara; Gifu, Elena-Patricia; Sandu, Ioana; Denoroy, Luc; Parrot, Sandrine

2014-03-01

Electrochemical methods are very often used to detect catecholamine and indolamine neurotransmitters separated by conventional reverse-phase high performance liquid chromatography (HPLC). The present paper presents the development of a chromatographic method to detect monoamines present in low-volume brain dialysis samples using a capillary column filled with sub-2μm particles. Several parameters (repeatability, linearity, accuracy, limit of detection) for this new ultrahigh performance liquid chromatography (UHPLC) method with electrochemical detection were examined after optimization of the analytical conditions. Noradrenaline, adrenaline, serotonin, dopamine and its metabolite 3-methoxytyramine were separated in 1μL of injected sample volume; they were detected above concentrations of 0.5-1nmol/L, with 2.1-9.5% accuracy and intra-assay repeatability equal to or less than 6%. The final method was applied to very low volume dialysates from rat brain containing monoamine traces. The study demonstrates that capillary UHPLC with electrochemical detection is suitable for monitoring dialysate monoamines collected at high sampling rate. Copyright © 2014 Elsevier B.V. All rights reserved.

Thermocapillary phenomena and performance limitations of a wickless heat pipe in microgravity.

PubMed

Kundan, Akshay; Plawsky, Joel L; Wayner, Peter C; Chao, David F; Sicker, Ronald J; Motil, Brian J; Lorik, Tibor; Chestney, Louis; Eustace, John; Zoldak, John

2015-04-10

A counterintuitive, thermocapillary-induced limit to heat- pipe performance was observed that is not predicted by current thermal-fluid models. Heat pipes operate under a number of physical constraints including the capillary, boiling, sonic, and entrainment limits that fundamentally affect their performance. Temperature gradients near the heated end may be high enough to generate significant Marangoni forces that oppose the return flow of liquid from the cold end. These forces are believed to exacerbate dry out conditions and force the capillary limit to be reached prematurely. Using a combination of image and thermal data from experiments conducted on the International Space Station with a transparent heat pipe, we show that in the presence of significant Marangoni forces, dry out is not the initial mechanism limiting performance, but that the physical cause is exactly the opposite behavior: flooding of the hot end with liquid. The observed effect is a consequence of the competition between capillary and Marangoni-induced forces. The temperature signature of flooding is virtually identical to dry out, making diagnosis difficult without direct visual observation of the vapor-liquid interface.

Respiratory Fluid Mechanics

NASA Astrophysics Data System (ADS)

Grotberg, James

2005-11-01

This brief overview of our groups activities includes liquid plug propagation in single and bifurcating tubes, a subject which pertains to surfactant delivery, liquid ventilation, pulmonary edema, and drowning. As the plug propagates, a variety of flow patterns may emerge depending on the parameters. It splits unevenly at airway bifurcations and can rupture, which reopens the airway to gas flow. Both propagation and rupture may damage the underlying airway wall cells. Another topic is surfactant dynamics and flow in a model of an oscillating alveolus. The analysis shows a nontrivial cycle-averaged surfactant concentration gradient along the interface that generates steady streaming. The steady streaming patterns particularly depend on the ratio of inspiration to expiration time periods and the sorption parameter. Vortices, single and multiple, may be achieved, as well as a saddle point configuration. Potential applications are pulmonary drug administration, cell-cell signaling pathways, and gene therapy. Finally, capillary instabilities which cause airway closure, and strategies for stabilization, will be presented. This involves the core-annular flow of a liquid-lined tube, where the core (air) is forced to oscillate axially. The stabilization mechanism is similar to that of a reversing butter knife, where the core shear wipes the growing liquid bulge, from the Rayleigh instability, back on to the tube wall during the main tidal volume stroke, but allows it to grow back as the stroke and shear turn around.

A novel IMSL tunable phase shifter for HMSIW-LWA-fed rectangular patches based on nematic liquid crystal

NASA Astrophysics Data System (ADS)

Fu, JiaHui; Raheem, Odai H.

2017-07-01

A novel IMSL tunable phase shifter for HMSIW-LWA-fed rectangular patches based on liquid crystal technology is proposed. Rectangular patches are used as radiators for the opening sidewall of the waveguide and matched section part for a unit cell. The transition structure is added for enhancing the efficiency of HMSIW-LWA due to converting most input power to the leaky mode. The novel IMSL phase shifter is used for investigating the tunable dielectric characteristics of N-LC by applying an electric field to the LC cell, which is controlled by the orientation angle of the LC molecules. Theoretically, the orientation angle is derived and solved numerically with the accurate method. As a result, the HMSIW-LWA can be tuned up to ± 25° for a fixed frequency by tuning the nematic LC with applied voltage from 0 to 20 V. In addition, the realized gain changed from 6 to 9.4 dB for a fixed tuned frequency, and 46° steerable for rest main beams range of the HMSIW-LWA in both forward and backward directions.

LABORATORY INVESTIGATION OF RESIDUAL LIQUID ORGANICS FROM SPILLS, LEAKS, AND THE DISPOSAL OF HAZARDOUS WASTES IN GROUNDWATER

EPA Science Inventory

Organic liquids that are essentially immiscible with water migrate through the subsurface under the influence of capillary, viscous, and buoyancy forces. These liquids originate from the improper disposal of hazardous wastes, and the spills and leaks of petroleum hydrocarbons a...

Low internal pressure in femtoliter water capillary bridges reduces evaporation rates.

PubMed

Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

2016-03-01

Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.

Theory of absorption integrated optical sensor of gaseous materials

NASA Astrophysics Data System (ADS)

Egorov, A. A.

2010-10-01

The eigen and noneigen (leaky) modes of a three-layer planar integrated optical waveguide are described. The dispersion relation of a three-layer planar waveguide and other dependences are derived, and the cutoff conditions are analyzed. The diagram of propagation constants of the guided and radiation modes of an irregular asymmetric three-layer waveguide and the dependence of the electric field amplitudes of radiation modes of substrate on vertical coordinate in a tantalum integrated optical waveguide are presented. The operating principles of an absorption integrated optical waveguide sensor are investigated. The dependences of sensitivity of an integrated optical waveguide sensor on the sensory cell length, the coupling efficiency of the laser radiation into the waveguide, the absorption cross-section of the studied material, and the level of additive statistical noise are investigated. Some of the prospective areas of application of integrated-optical waveguide sensors are outlined.

Development and study of a heat pipe with dielectric properties

NASA Astrophysics Data System (ADS)

Semena, M. G.; Gershuni, A. N.; Chepurnoi, A. B.

Requirements for the structural elements of heat pipes with dielectric properties are examined. To obtain information necessary for the thermal analysis of heat pipes, a study is made of the capillary-transport characteristics of a dielectric capillary structure consisting of quartz fibers; the capillary pressure and the liquid penetration coefficient are determined. The results of the study are used to develop dielectric heat pipes for the cooling of a vacuum electronic instrument. Experimentally determined characteristics of the heat pipes are presented.

Looking for Speed!! Go Optical Ultra-Fast Photonic Logic Gates for the Future Optical Communication and Computing

NASA Technical Reports Server (NTRS)

Abdeldayem, Hossin; Frazier, Donald O.; Penn, Benjamin; Paley, Mark S.

2003-01-01

Recently, we developed two ultra-fast all-optical switches in the nanosecond and picosecond regimes. The picosecond switch is made of a polydiacetylene thin film coated on the interior wall of a hollow capillary of approximately 50 micron diameter by a photo-polymerization process. In the setup a picosecond Nd:YAG laser at 10 Hz and at 532 nm with a pulse duration of approximately 40 ps was sent collinearly along a cw He-Ne laser beam and both were waveguided through the hollow capillary. The setup functioned as an Exclusive OR gate. On the other hand, the material used in the nanosecond switch is a phthalocyanine thin film, deposited on a glass substrate by a vapor deposition technique. In the setup a nanosecond, 10 Hz, Nd:YAG laser of 8 ns pulse duration was sent collinearly along a cw He-Ne laser beam and both were wave-guided through the phthalocyanine thin film. The setup in this case functioned as an all-optical AND logic gate. The characteristic table of the ExOR gate in polydiacetylene film was attributed to an excited state absorption process, while that of the AND gate was attributed to a saturation process of the first excited state. Both mechanisms were thoroughly investigated theoretically and found to agree remarkably well with the experimental results. An all-optical inverter gate has been designed but has not yet been demonstrated. The combination of all these three gates form the foundation for building all the necessary gates needed to build a prototype of an all-optical system.

Polymer microfluidic device replacing fluids using only capillary force

NASA Astrophysics Data System (ADS)

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

2005-02-01

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

Porous micropillar structures for retaining low surface tension liquids.

PubMed

Agonafer, Damena D; Lee, Hyoungsoon; Vasquez, Pablo A; Won, Yoonjin; Jung, Ki Wook; Lingamneni, Srilakshmi; Ma, Binjian; Shan, Li; Shuai, Shuai; Du, Zichen; Maitra, Tanmoy; Palko, James W; Goodson, Kenneth E

2018-03-15

The ability to manipulate fluid interfaces, e.g., to retain liquid behind or within porous structures, can be beneficial in multiple applications, including microfluidics, biochemical analysis, and the thermal management of electronic systems. While there are a variety of strategies for controlling the disposition of liquid water via capillarity, such as the use of chemically modified porous adhesive structures and capillary stop valves or surface geometric features, methods that work well for low surface tension liquids are far more difficult to implement. This study demonstrates the microfabrication of a silicon membrane that can retain exceptionally low surface tension fluorinated liquids against a significant pressure difference across the membrane via an array of porous micropillar structures. The membrane uses capillary forces along the triple phase contact line to maintain stable liquid menisci that yield positive working Laplace pressures. The micropillars have inner diameters and thicknesses of 1.5-3 μm and ∼1 μm, respectively, sustaining Laplace pressures up to 39 kPa for water and 9 kPa for Fluorinert™ (FC-40). A theoretical model for predicting the change in pressure as the liquid advances along the porous micropillar structure is derived based on a free energy analysis of the liquid meniscus with capped spherical geometry. The theoretical prediction was found to overestimate the burst pressure compared with the experimental measurements. To elucidate this deviation, transient numerical simulations based on the Volume of Fluid (VOF) were performed to explore the liquid pressure and evolution of meniscus shape under different flow rates (i.e., Capillary numbers). The results from VOF simulations reveal strong dynamic effects where the anisotropic expansion of liquid along the outer micropillar edge leads to an irregular meniscus shape before the liquid spills along the micropillar edge. These findings suggest that the analytical prediction of burst Laplace pressure obtained under quasi-static condition (i.e., equilibrium thermodynamic analysis under low capillary number) is not applicable to highly dynamic flow conditions, where the liquid meniscus shape deformation by flow perturbation cannot be restored by surface tension force instantaneously. Therefore, the critical burst pressure is dependent on the liquid velocity and viscosity under dynamic flow conditions. A numerical simulation using Surface Evolver also predicts that surface defects along the outer micropillar edge can yield up to 50% lower Laplace pressures than those predicted with ideal feature geometries. The liquid retention strategy developed here can facilitate the routing and phase management of dielectric working fluids for application in heat exchangers. Further improvements in the retention performance can be realized by optimizing the fabrication process to reduce surface defects. Copyright © 2017 Elsevier Inc. All rights reserved.

Multiscale spectroscopy using a monolithic liquid core waveguide with laterally attached fiber ports.

PubMed

Kröckel, Lars; Frosch, Torsten; Schmidt, Markus A

2015-05-22

In conventional absorption spectrometers, the range of accessible concentrations of analytes in aqueous solution is significantly limited by the dynamic range of the measurement system. Here we introduce the concept of multiscale spectroscopy allowing extending that range by orders of magnitude within one single device. The concept relies on using multiple light-sample interaction lengths, boosting the accessible concentration range by a particular extension factor. We experimentally implement our concept by a liquid core waveguide having multiple fiber ports side-wise attached to the waveguide, thus probing the light propagating inside the core at predefined distances from the input. This configuration provides three orders of magnitude of interaction length in one device. To verify the concept we exemplarily determine the concentrations of nitrate and of Rhodamine 6G in water, showing one hundred times improved measurement capabilities. The multiscale spectrometer uses the entire sample volume and allows the simultaneous measurement of fluorescence and attenuance. Due to its integrated design and the extended measurements capabilities, we anticipate application of our device in many application-relevant areas such as water quality analysis or environmental science. Copyright © 2015 Elsevier B.V. All rights reserved.

Split and flow: reconfigurable capillary connection for digital microfluidic devices.

PubMed

Lapierre, Florian; Harnois, Maxime; Coffinier, Yannick; Boukherroub, Rabah; Thomy, Vincent

2014-09-21

Supplying liquid to droplet-based microfluidic microsystems remains a delicate task facing the problems of coupling continuous to digital or macro- to microfluidic systems. Here, we take advantage of superhydrophobic microgrids to address this problem. Insertion of a capillary tube inside a microgrid aperture leads to a simple and reconfigurable droplet generation setup.

Application of the string method to the study of critical nuclei in capillary condensation.

PubMed

Qiu, Chunyin; Qian, Tiezheng; Ren, Weiqing

2008-10-21

We adopt a continuum description for liquid-vapor phase transition in the framework of mean-field theory and use the string method to numerically investigate the critical nuclei for capillary condensation in a slit pore. This numerical approach allows us to determine the critical nuclei corresponding to saddle points of the grand potential function in which the chemical potential is given in the beginning. The string method locates the minimal energy path (MEP), which is the most probable transition pathway connecting two metastable/stable states in configuration space. From the MEP, the saddle point is determined and the corresponding energy barrier also obtained (for grand potential). Moreover, the MEP shows how the new phase (liquid) grows out of the old phase (vapor) along the most probable transition pathway, from the birth of a critical nucleus to its consequent expansion. Our calculations run from partial wetting to complete wetting with a variable strength of attractive wall potential. In the latter case, the string method presents a unified way for computing the critical nuclei, from film formation at solid surface to bulk condensation via liquid bridge. The present application of the string method to the numerical study of capillary condensation shows the great power of this method in evaluating the critical nuclei in various liquid-vapor phase transitions.

Liquid spreading on ceramic-coated carbon nanotube films and patterned microstructures

NASA Astrophysics Data System (ADS)

Zhao, Hangbo; Hart, A. John

2015-11-01

We study the capillary-driven liquid spreading behavior on films and microstructures of ceramic-coated vertically aligned carbon nanotubes (CNTs) fabricated on quartz substrates. The nanoscale porosity and micro-scale dimensions of the CNT structures, which can be precisely varied by the fabrication process, enable quantitative measurements that can be related to analytical models of the spreading behavior. Moreover, the conformal alumina coating by atomic layer deposition (ALD) prevents capillary-induced deformation of the CNTs upon meniscus recession, which has complicated previous studies of this topic. Washburn-like liquid spreading behavior is observed on non-patterned CNT surfaces, and is explained using a scaling model based on the balance of capillary driving force and the viscous drag force. Using these insights, we design patterned surfaces with controllable spreading rates and study the contact line pinning-depinning behavior. The nanoscale porosity, controllable surface chemistry, and mechanical stability of coated CNTs provide significantly enhanced liquid-solid interfacial area compared to solid microstructures. As a result, these surface designs may be useful for applications such as phase-change heat transfer and electrochemical energy storage. Funding for this project is provided by the National Institutes of Health and the MIT Center for Clean Water and Clean Energy supported by the King Fahd University of Petroleum and Minerals.

Capillary thermoconcentration instability and processes of heat and mass transfer in laser technology

NASA Astrophysics Data System (ADS)

Maiorov, Vladimir S.

2002-04-01

The paper gives a description of the phenomenon that has a considerable, and often a decisive, influence on the course of physical processes under laser radiation interaction with a substance having at least one liquid phase. The explanation of the essence of this phenomenon lies at the intersection of two branches of science: mechanics of liquids and gases, and physical chemistry (thermodynamics of heterogeneous systems). Capillary thermo-concentration instability (CTCI) is present at any non-isotropic input of energy to a heterogeneous thermodynamical system having several phases. This instability manifests itself at the phase boundary and causes processes of mass transfer, redistribution of components, emergence of new phases, relaxation vibrations. This phenomenon is most pronounced in local processes at interaction of laser radiation with matter. The theory and practice of this phenomenon unite and describe a new class of effects widely spread in nature, which play a decisive role in many physical and chemical processes and find even more various spheres of practical application. A number of examples of capillary thermo- concentration instability application are given: separation of liquid mixtures to components under thermal action of laser beam; a new method of thermal silver-free photography; control of liquid metal convection in laser alloying.

Determination of dasatinib in the tablet dosage form by ultra high performance liquid chromatography, capillary zone electrophoresis, and sequential injection analysis.

PubMed

Gonzalez, Aroa Garcia; Taraba, Lukáš; Hraníček, Jakub; Kozlík, Petr; Coufal, Pavel

2017-01-01

Dasatinib is a novel oral prescription drug proposed for treating adult patients with chronic myeloid leukemia. Three analytical methods, namely ultra high performance liquid chromatography, capillary zone electrophoresis, and sequential injection analysis, were developed, validated, and compared for determination of the drug in the tablet dosage form. The total analysis time of optimized ultra high performance liquid chromatography and capillary zone electrophoresis methods was 2.0 and 2.2 min, respectively. Direct ultraviolet detection with detection wavelength of 322 nm was employed in both cases. The optimized sequential injection analysis method was based on spectrophotometric detection of dasatinib after a simple colorimetric reaction with folin ciocalteau reagent forming a blue-colored complex with an absorbance maximum at 745 nm. The total analysis time was 2.5 min. The ultra high performance liquid chromatography method provided the lowest detection and quantitation limits and the most precise and accurate results. All three newly developed methods were demonstrated to be specific, linear, sensitive, precise, and accurate, providing results satisfactorily meeting the requirements of the pharmaceutical industry, and can be employed for the routine determination of the active pharmaceutical ingredient in the tablet dosage form. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of wettability of a porous stainless steel on thermally induced liquid-vapor interface behavior

NASA Astrophysics Data System (ADS)

Oka, C.; Odagiri, K.; Nagano, H.

2017-12-01

Control of thermally induced liquid-vapor interface behavior at the contact surface of porous media is crucial for development of two-phase heat transfer devices such as loop heat pipes. The behavior experiences three modes with increase of heat flux, and the middle mode possesses the highest heat transfer performance. In this paper, the effect of improving wettability of the porous media is demonstrated experimentally and numerically for the first time, in particular with regard to the effect on a domain of the middle mode. Ethanol wettability of a porous stainless steel was improved via a facile method, which was a simple acid treatment. As a result, the domain of the middle mode was extended as a consequence of the wettability improvement. The mode transfers from the middle to the last one when the pressure drop in the liquid supply exceeds the capillary pressure of liquid bridges formed between the heating plate and the porous medium. Hence, the extension of the domain suggested that the capillary pressure was increased by the wettability improvement. This was verified via numerical calculation. The calculated capillary pressure was increased by 7% after improving wettability, which resulted in the extension of the domain of the middle mode.

Gas adsorption and capillary condensation in nanoporous alumina films.

PubMed

Casanova, Fèlix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Ruminski, Anne M; Sailor, Michael J; Schuller, Ivan K

2008-08-06

Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation.

Percolation study for the capillary ascent of a liquid through a granular soil

NASA Astrophysics Data System (ADS)

Cárdenas-Barrantes, Manuel Antonio; Muñoz, José Daniel; Araujo, Nuno Machado

2017-06-01

Capillary rise plays a crucial role in the construction of road embankments in flood zones, where hydrophobic compounds are added to the soil to suppress the rising of water and avoid possible damage of the pavement. Water rises through liquid bridges, menisci and trimers, whose width and connectivity depends on the maximal half-length λ of the capillary bridges among grains. Low λs generate a disconnect structure, with small clusters everywhere. On the contrary, for high λ, create a percolating cluster of trimers and enclosed volumes that form a natural path for capillary rise. Hereby, we study the percolation transition of this geometric structure as a function of λ on a granular media of monodisperse spheres in a random close packing. We determine both the percolating threshold λc = (0.049 ± 0.004)R (with R the radius of the granular spheres), and the critical exponent of the correlation length v = 0.830 ± 0.051, suggesting that the percolation transition falls into the universality class of ordinary percolation.

Occlusion of retinal capillaries caused by glial cell proliferation in chronic ocular inflammation.

PubMed

Bianchi, E; Ripandelli, G; Feher, J; Plateroti, A M; Plateroti, R; Kovacs, I; Plateroti, P; Taurone, S; Artico, M

2015-01-01

The inner blood-retinal barrier is a gliovascular unit in which glial cells surround capillary endothelial cells and regulate retinal capillaries by paracrine interactions. During chronic ocular inflammation, microvascular complications can give rise to vascular proliferative lesions, which compromise visual acuity. This pathologic remodelling caused by proliferating Müller cells determines occlusion of retinal capillaries. The aim of the present study was to identify qualitative and quantitative alterations in the retinal capillaries in patients with post-traumatic chronic ocular inflammation or post-thrombotic vascular glaucoma. Moreover, we investigated the potential role of vascular endothelial growth factor (VEGF) and pro-inflammatory cytokines in retinal inflammation. Our electron microscopy findings demonstrated that during chronic ocular inflammation, thickening of the basement membrane, loss of pericytes and endothelial cells and proliferation of Müller cells occur with irreversible occlusion of retinal capillaries. Angiogenesis takes place as part of a regenerative reaction that results in fibrosis. We believe that VEGF and pro-inflammatory cytokines may be potential therapeutic targets in the treatment of this disease although further studies are required to confirm these findings.

Continuous tuneable droplet ejection via pulsed surface acoustic wave jetting.

PubMed

Castro, Jasmine O; Ramesan, Shwathy; Rezk, Amgad R; Yeo, Leslie Y

2018-05-30

We report a miniaturised platform for continuous production of single or multiple liquid droplets with diameters between 60 and 500 μm by interfacing a capillary-driven self-replenishing liquid feed with pulsed excitation of focussed surface acoustic waves (SAWs). The orifice-free operation circumvents the disadvantages of conventional jetting systems, which are often prone to clogging that eventuates in rapid degradation of the operational performance. Additionally, we show the possibility for flexibly tuning the ejected droplet size through the pulse width duration, thus avoiding the need for a separate device for every different droplet size required, as is the case for systems in which the droplet size is set by nozzles and orifices, as well as preceding ultrasonic jetting platforms where the droplet size is controlled by the operating frequency. Further, we demonstrate that cells can be jetted and hence printed onto substrates with control over the cell density within the droplets down to single cells. Given that the jetting does not lead to significant loss to the cell's viability or ability to proliferate, we envisage that this versatile jetting method can potentially be exploited with further development for cell encapsulation, dispensing and 3D bioprinting applications.

Elasto-capillary interactions of drops and particles

NASA Astrophysics Data System (ADS)

Snoeijer, Jacco; Pandey, Anupam; Karpitschka, Stefan; Nawijn, Charlotte; Botto, Lorenzo; Andreotti, Bruno

2017-11-01

The interaction of solid particles floating on a liquid interface is popularly known as the Cheerios effect. Here we present similar interactions for particles and droplets on elastic surfaces, mediated by elastic deformation. We start with the Inverted Cheerios effect, by considering liquid drops on a solid gel. Remarkably, the interaction can be tuned from attractive to repulsive, as shown experimentally and theoretically. We then turn to more general cases of particles on elastic layers, for which new interaction laws are derived. An overview is given on the various regimes, including the crossover from purely elastic to purely capillary interfaces. ERC Consolidator Grant 616918.

ICSH recommendations for assessing automated high-performance liquid chromatography and capillary electrophoresis equipment for the quantitation of HbA2.

PubMed

Stephens, A D; Colah, R; Fucharoen, S; Hoyer, J; Keren, D; McFarlane, A; Perrett, D; Wild, B J

2015-10-01

Automated high performance liquid chromatography and Capillary electrophoresis are used to quantitate the proportion of Hemoglobin A2 (HbA2 ) in blood samples order to enable screening and diagnosis of carriers of β-thalassemia. Since there is only a very small difference in HbA2 levels between people who are carriers and people who are not carriers such analyses need to be both precise and accurate. This paper examines the different parameters of such equipment and discusses how they should be assessed. © 2015 John Wiley & Sons Ltd.

Miniaturised electrically actuated high pressure injection valve for portable capillary liquid chromatography.

PubMed

Li, Yan; Pace, Kirsten; Nesterenko, Pavel N; Paull, Brett; Stanley, Roger; Macka, Mirek

2018-04-01

A miniaturised high pressure 6-port injection valve has been designed and evaluated for its performance in order to facilitate the development of portable capillary high performance liquid chromatography (HPLC). The electrically actuated valve features a very small size (65 × 19 × 19mm) and light weight (33g), and therefore can be easily integrated in a miniaturised modular capillary LC system suited for portable field analysis. The internal volume of the injection valve was determined as 98 nL. The novel conical shape of the stator and rotor and the spring-loaded rotor performed well up to 32MPa (4641psi), the maximum operating pressure investigated. Suitability for application was demonstrated using a miniaturised capillary LC system applied to the chromatographic separation of a mixture of biogenic amines and common cations. The RSD (relative standard deviation) values of retention times and peak areas of 6 successive runs were 0.5-0.7% and 1.8-2.8% for the separation of biogenic amines, respectively, and 0.1-0.2% and 2.1-3.0% for the separation of cations, respectively. This performance was comparable with bench-top HPLC systems thus demonstrating the applicability of the valve for use in portable and miniaturised capillary HPLC systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Investigation of the capillary flow through open surface microfluidic structures

NASA Astrophysics Data System (ADS)

Taher, Ahmed; Jones, Benjamin; Fiorini, Paolo; Lagae, Liesbet

2017-02-01

The passive nature of capillary microfluidics for pumping and actuation of fluids is attractive for many applications including point of care medical diagnostics. For such applications, there is often the need to spot dried chemical reagents in the bottom of microfluidic channels after device fabrication; it is often more practical to have open surface devices (i.e., without a cover or lid). However, the dynamics of capillary driven flow in open surface devices have not been well studied for many geometries of interest. In this paper, we investigate capillary flow in an open surface microchannel with a backward facing step. An analytical model is developed to calculate the capillary pressure as the liquid-vapor interface traverses a backward facing step in an open microchannel. The developed model is validated against results from Surface Evolver liquid-vapor surface simulations and ANSYS Fluent two-phase flow simulations using the volume of fluid approach. Three different aspect ratios (inlet channel height by channel width) were studied. The analytical model shows good agreement with the simulation results from both modeling methods for all geometries. The analytical model is used to derive an expression for the critical aspect ratio (the minimum channel aspect ratio for flow to proceed across the backward facing step) as a function of contact angle.

The CE-Way of Thinking: "All Is Relative!".

PubMed

Schmitt-Kopplin, Philippe; Fekete, Agnes

2016-01-01

Over the last two decades the development of capillary electrophoresis instruments lead to systems with programmable sampler, separation column, separation buffer, and detection devices comparable visually in many aspects to the setup of classical chromatography.Two processes make capillary electrophoresis essentially different from chromatography and are the basis of the CE-way of thinking, namely, the injection type and the liquid flow within the capillary. (1) When the injection is made hydrodynamically (such as in most of the found applications in the literature), the injected volumes are directly dependent on the type and size of the separation capillary. (2) The buffer velocity is not pressure driven as in liquid chromatography but electrokinetically governed by the quality of the capillary surface (separation buffer dependant surface charge) inducing an electroosmotic flow (EOF). The EOF undergoes small variations and is not necessarily identical from one separation or day to the other. The direct consequence is an apparent nonreproducible migration time of the analytes, even though the own velocity of the ions is the same.The effective mobility (field strength normalized velocity) of the ions is a possible parameterization from acquired timescale to effective mobility-scale electropherograms leading to a reproducible visualization and better quantification with a direct relation to structural characters of the analytes (i.e., charge and size-see chapter on semiempirical modelization).

Capillary trapping of particles in thin-film flows

NASA Astrophysics Data System (ADS)

Dressaire, Emilie; Gomez, Michael; Colnet, Benedicte; Sauret, Alban

2017-11-01

When a thin layer of suspension flows over a substrate, some particles remain trapped on the solid surface. When the thickness of the liquid layer is comparable to the particle size, the particles deform the liquid interface, which leads to local interactions. These effects modify the transport of particles and the dynamics of the liquid films. Here, we characterize how capillary interactions affect the transport and deposition of non-Brownian particles moving in thin liquid films and the resulting loss of transported material. We focus on gravitational drainage flows, in which the film thickness becomes comparable to the particle size. Depending on the concentration of particles, we find that the drainage dynamics exhibits behavior that cannot be captured with a continuum model, due to the deposition of particles on the substrate. ANR-16-CE30-0009 & CNRS-PICS-07242 & ACS-PRF 55845-ND9.

Capillary trapping in thin-film flows of particles

NASA Astrophysics Data System (ADS)

Sauret, Alban; Gomez, Michael; Dressaire, Emilie

Flows of suspensions have been modeled on a continuum level by using constitutive relations to capture how the viscosity varies with the particle concentration. However, in thin liquid films, where the thickness of the liquid layer is comparable to the particle size, the particles deform the liquid interface, which leads to local interactions. These effects modify the transport of particles and could result in the contamination of the surface and the loss of transported material. Here, we characterize how capillary interactions affect the transport and deposition of non-Brownian particles moving in thin liquid films. We focus on gravitational drainage flows, in which the film thickness becomes comparable to the particle size. Depending on the concentration of particles, we find that the dynamics of the drainage exhibits behavior that cannot be captured with a Newtonian model, due to the deposition of particles on the substrate. ANR-16-CE30-0009 and CNRS-PICS-07242.

Isolation and recovery of selected polybrominated diphenyl ethers from human serum and sheep serum: coupling reversed-phase solid-phase disk extraction and liquid-liquid extraction techniques with a capillary gas chromatographic electron capture negative ion mass spectrometric determinative technique.

PubMed

Loconto, Paul R; Isenga, David; O'Keefe, Michael; Knottnerus, Mark

2008-01-01

Polybrominated diphenyl ethers (PBDEs) are isolated and recovered with acceptable percent recoveries from human serum via liquid-liquid extraction and column chromatographic cleanup and fractionation with quantitation using capillary gas chromatography-mass spectrometry with electron capture negative ion and selected ion monitoring. PBDEs are found in unspiked serum. An alternative sample preparation approach is developed using sheep serum that utilizes a formic acid pre-treatment followed by reversed-phase solid-phase disk extraction and normal-phase solid-phase cleanup using acidified silica gel that yields>50% recoveries. When these percent recoveries are combined with a minimized phase ratio for human serum and very low instrument detection limits, method detection limits below 500 parts-per-trillion are realized.

Effects of gravity, inertia, and surfactant on steady plug propagation in a two-dimensional channel

NASA Astrophysics Data System (ADS)

Zheng, Y.; Fujioka, H.; Grotberg, J. B.

2007-08-01

Liquid plugs may form in pulmonary airways during the process of liquid instillation or removal in many clinical treatments. Studies have shown that the effectiveness of these treatments may depend on how liquids distribute in the lung. Better understanding of the fundamental fluid mechanics of liquid plug transport will facilitate treatment strategies. In this paper, we develop a numerical model of steady plug propagation driven by gravity and pressure in a two-dimensional liquid-lined channel oriented at an angle α with respect to gravity. We investigate the effects of gravity through the Bond number, Bo, and α; the plug propagation speed through the capillary number, Ca, or the Reynolds number, Re; the plug length LP, and the surfactant concentration C0. Without gravity, i.e., Bo =0, the plug is symmetric, and there are two regimes for the flow: two wall layers and two trapped vortices in the core. There is no flow interaction between the upper and lower half plug domains. When Bo ≠0 and α ≠0, π, fluid is found to flow from the upper precursor film, through the core and into the lower trailing film. Then the number of vortices can be zero, one, or two, depending on the flow parameters. The vortices have stagnation points on the interface when C0=0, however when the surfactant is present (C0>0), the vortices detach from the interface and create saddle points inside the core. The front meniscus develops a capillary surface wave extending into the precursor film. This is where the film is thinnest and thus the wall shear stress is highest, as high as ˜100dyn /cm2 in adult airways, which indicates a significant risk of pulmonary airway epithelial cell damage. Adding surfactant can decrease the peak magnitude of the shear stress, thus reducing the risk of cell damage. The prebifurcation asymmetry of the plug is quantified by the volume ratio, Vr, defined as the ratio of the liquid above to that below the center line of the channel. Vr is found to increase with LP, Ca, Re, and C0, while it decreases with Bo. The total mass left behind in the trailing films increases with Bo for any α at α >2π/5, Ca and α for any value of Bo >0.

Integrating cell on chip—Novel waveguide platform employing ultra-long optical paths

NASA Astrophysics Data System (ADS)

Fohrmann, Lena Simone; Sommer, Gerrit; Pitruzzello, Giampaolo; Krauss, Thomas F.; Petrov, Alexander Yu.; Eich, Manfred

2017-09-01

Optical waveguides are the most fundamental building blocks of integrated optical circuits. They are extremely well understood, yet there is still room for surprises. Here, we introduce a novel 2D waveguide platform which affords a strong interaction of the evanescent tail of a guided optical wave with an external medium while only employing a very small geometrical footprint. The key feature of the platform is its ability to integrate the ultra-long path lengths by combining low propagation losses in a silicon slab with multiple reflections of the guided wave from photonic crystal (PhC) mirrors. With a reflectivity of 99.1% of our tailored PhC-mirrors, we achieve interaction paths of 25 cm within an area of less than 10 mm2. This corresponds to 0.17 dB/cm effective propagation which is much lower than the state-of-the-art loss of approximately 1 dB/cm of single mode silicon channel waveguides. In contrast to conventional waveguides, our 2D-approach leads to a decay of the guided wave power only inversely proportional to the optical path length. This entirely different characteristic is the major advantage of the 2D integrating cell waveguide platform over the conventional channel waveguide concepts that obey the Beer-Lambert law.

Electromagnetic liquid pistons for capillarity-based pumping.

PubMed

Malouin, Bernard A; Vogel, Michael J; Olles, Joseph D; Cheng, Lili; Hirsa, Amir H

2011-02-07

The small scales associated with lab-on-a-chip technologies lend themselves well to capillarity-dominated phenomena. We demonstrate a new capillarity-dominated system where two adjoining ferrofluid droplets can behave as an electronically-controlled oscillator or switch by an appropriate balance of magnetic, capillary, and inertial forces. Their oscillatory motion can be exploited to displace a surrounding liquid (akin to an axial piston pump), forming electromagnetic "liquid pistons." Such ferrofluid pistons can pump a precise volume of liquid via finely tunable amplitudes (cf. pump stroke) or resonant frequencies (cf. pump speed) with no solid moving parts for long-term operation without wear in a small device. Furthermore, the rapid propagation of electromagnetic fields and the favorable scaling of capillary forces with size permit micron sized devices with very fast operating speeds (∼kHz). The pumping dynamics and performance of these liquid pistons is explored, with experimental measurements showing good agreement with a spherical cap model. While these liquid pistons may find numerous applications in micro- and mesoscale fluidic devices (e.g., remotely activated drug delivery), here we demonstrate the use of these liquid pistons in capillarity-dominated systems for chip-level, fast-acting adaptive liquid lenses with nearly perfect spherical interfaces.

Re-addressable Interconnects with Light-Induced Waveguides in Liquid Crystals

DTIC Science & Technology

2011-08-09

average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data...15. SUBJECT TERMS EOARD, Liquid Crystals, Laser beam control 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT...external stimuli, their performance is far from optimal: their response time can be larger than 100ms and they exhibit transverse fluctuations due

Tantala-based sol-gel coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

PubMed

Tran, MinhPhuong; Turner, Erica B; Segro, Scott S; Fang, Li; Seyyal, Emre; Malik, Abdul

2017-11-03

A sol-gel organic-inorganic hybrid sorbent, consisting of chemically integrated tantalum (V) ethoxide (TaEO) and polypropylene glycol methacrylate (PPGM), was developed for capillary microextraction (CME). The sol-gel sorbent was synthesized within a fused silica capillary through hydrolytic polycondensation of TaEO and chemical incorporation of PPGM into the evolving sol-gel tantala network. A part of the organic-inorganic hybrid sol-gel network evolving in the vicinity of the capillary walls had favorable conditions to get chemically bonded to the silanol groups on the capillary surface forming a surface-bonded coating. The newly developed sol-gel sorbent was employed to isolate and enrich a variety of analytes from aqueous samples for on-line analysis by high-performance liquid chromatography (HPLC) equipped with a UV detector. CME was performed on aqueous samples containing trace concentrations of analytes representing polycyclic aromatic hydrocarbons, ketones, alcohols, amines, nucleosides, and nucleotides. This sol-gel hybrid coating provided efficient extraction with CME-HPLC detection limits ranging from 4.41pM to 28.19 pM. Due to direct chemical bonding between the sol-gel sorbent coating and the fused silica capillary inner surface, this sol-gel sorbent exhibited enhanced solvent stability. The sol-gel tantala-based sorbent also exhibited excellent pH stability over a wide pH range (pH 0-pH 14). Furthermore, it displayed great performance reproducibility in CME-HPLC providing run-to-run HPLC peak area relative standard deviation (RSD) values between 0.23% and 3.83%. The capillary-to-capillary RSD (n=3), characterizing capillary preparation method reproducibility, ranged from 0.24% to 4.11%. The results show great performance consistency and application potential for the sol-gel tantala-PPGM sorbent in various fields including biomedical, pharmaceutical, and environmental areas. Copyright © 2017 Elsevier B.V. All rights reserved.

HPTAM, a two-dimensional Heat Pipe Transient Analysis Model, including the startup from a frozen state

NASA Technical Reports Server (NTRS)

Tournier, Jean-Michel; El-Genk, Mohamed S.

1995-01-01

A two-dimensional Heat Pipe Transient Analysis Model, 'HPTAM,' was developed to simulate the transient operation of fully-thawed heat pipes and the startup of heat pipes from a frozen state. The model incorporates: (a) sublimation and resolidification of working fluid; (b) melting and freezing of the working fluid in the porous wick; (c) evaporation of thawed working fluid and condensation as a thin liquid film on a frozen substrate; (d) free-molecule, transition, and continuum vapor flow regimes, using the Dusty Gas Model; (e) liquid flow and heat transfer in the porous wick; and (f) thermal and hydrodynamic couplings of phases at their respective interfaces. HPTAM predicts the radius of curvature of the liquid meniscus at the liquid-vapor interface and the radial location of the working fluid level (liquid or solid) in the wick. It also includes the transverse momentum jump condition (capillary relationship of Pascal) at the liquid-vapor interface and geometrically relates the radius of curvature of the liquid meniscus to the volume fraction of vapor in the wick. The present model predicts the capillary limit and partial liquid recess (dryout) in the evaporator wick, and incorporates a liquid pooling submodel, which simulates accumulation of the excess liquid in the vapor core at the condenser end.

Plasma L-ergothioneine measurement by high-performance liquid chromatography and capillary electrophoresis after a pre-column derivatization with 5-iodoacetamidofluorescein (5-IAF) and fluorescence detection.

PubMed

Sotgia, Salvatore; Pisanu, Elisabetta; Pintus, Gianfranco; Erre, Gian Luca; Pinna, Gerard Aime; Deiana, Luca; Carru, Ciriaco; Zinellu, Angelo

2013-01-01

Two sensitive and reproducible capillary electrophoresis and high-performance liquid chromatography-fluorescence procedures were established for quantitative determination of L-egothioneine in plasma. After derivatization of L-ergothioneine with 5-iodoacetamidofluorescein, the separation was carried out by HPLC on an ODS-2 C-18 sperisorb column by using a linear gradient elution and by HPCE on an uncoated fused silica capillary, 50 µm id, and 60 cm length. The methods were validated and found to be linear in the range of 0.3 to 10 µmol/l. The limit of quantification was 0.27 µmol/l for HPCE and 0.15 µmol/l for HPLC. The variations for intra- and inter-assay precision were around 6 RSD%, and the mean recovery accuracy close to 100% (96.11%).

Plasma L-Ergothioneine Measurement by High-Performance Liquid Chromatography and Capillary Electrophoresis after a Pre-Column Derivatization with 5-Iodoacetamidofluorescein (5-IAF) and Fluorescence Detection

PubMed Central

Sotgia, Salvatore; Pisanu, Elisabetta; Pintus, Gianfranco; Erre, Gian Luca; Pinna, Gerard Aime; Deiana, Luca; Carru, Ciriaco; Zinellu, Angelo

2013-01-01

Two sensitive and reproducible capillary electrophoresis and high-performance liquid chromatography-fluorescence procedures were established for quantitative determination of L-egothioneine in plasma. After derivatization of L-ergothioneine with 5-iodoacetamidofluorescein, the separation was carried out by HPLC on an ODS-2 C-18 sperisorb column by using a linear gradient elution and by HPCE on an uncoated fused silica capillary, 50 µm id, and 60 cm length. The methods were validated and found to be linear in the range of 0.3 to 10 µmol/l. The limit of quantification was 0.27 µmol/l for HPCE and 0.15 µmol/l for HPLC. The variations for intra- and inter-assay precision were around 6 RSD%, and the mean recovery accuracy close to 100% (96.11%). PMID:23922985

Laser printed glass planar lightwave circuits with integrated fiber alignment structures

NASA Astrophysics Data System (ADS)

Desmet, A.; Radosavljevic, A.; Missinne, J.; Van Thourhout, D.; Van Steenberge, G.

2018-02-01

Femtosecond laser inscription allows straightforward manufacturing of glass planar lightwave circuits such as waveguides, interferometers, directional couplers, resonators and more complex structures. Fiber alignment structures are needed to facilitate communication with the glass planar lightwave circuit. In this study, a technique is described to create optical waveguides and alignment structures in the same laser exposure step. Using an industrial ytterbium-doped 1030 nm fiber laser pulses of 400 fs were focused into glass with a 0.4 NA objective causing permanent alteration of the material. Depending on laser parameters this modification allows direct writing of waveguides or the creation of channels after exposing the irradiated volumes to an etchant such as KOH. Writing of channels and waveguides with different laser powers, frequencies, polarisations, stage translation speeds and scan densities were investigated in fused silica and borosilicate glass. Waveguides with controlled dimensions were created, as well as etched U-grooves with a diameter of 126 μm and a sidewall roughness Ra of 255 nm. Cut back measurements were performed giving a waveguide propagation loss of 1.1 dB/cm in borosilicate glass. A coupling loss of 0.7 dB was measured for a transition between the waveguide and standard single mode fiber at 1550 nm, using index matching liquid. The described technique eliminates active alignment requirements and is useful for many applications such as microfluidic sensing, PLCs, fan-out connectors for multicore fibers and quantum optical networks.

Method of fabricating optical waveguides by ion implantation doping

DOEpatents

Appleton, Bill R.; Ashley, Paul R.; Buchal, Christopher J.

1989-01-01

A method for fabricating high-quality optical waveguides in optical quality oxide crystals by ion implantation doping and controlled epitaxial recrystallization is provided. Masked LiNbO.sub.3 crystals are implanted with high concentrations of Ti dopant at ion energies of about 350 keV while maintaining the crystal near liquid nitrogen temperature. Ion implantation doping produces an amorphous, Ti-rich nonequilibrium phase in the implanted region. Subsequent thermal annealing in a water-saturated oxygen atmosphere at up to 1000.degree. C. produces solid-phase epitaxial regrowth onto the crystalline substrate. A high-quality single crystalline layer results which incorporates the Ti into the crystal structure at much higher concentrations than is possible by standard diffusion techniques, and this implanted region has excellent optical waveguides properties.

Confinement-Driven Phase Separation of Quantum Liquid Mixtures

NASA Astrophysics Data System (ADS)

Prisk, T. R.; Pantalei, C.; Kaiser, H.; Sokol, P. E.

2012-08-01

We report small-angle neutron scattering studies of liquid helium mixtures confined in Mobil Crystalline Material-41 (MCM-41), a porous silica glass with narrow cylindrical nanopores (d=3.4nm). MCM-41 is an ideal model adsorbent for fundamental studies of gas sorption in porous media because its monodisperse pores are arranged in a 2D triangular lattice. The small-angle scattering consists of a series of diffraction peaks whose intensities are determined by how the imbibed liquid fills the pores. Pure He4 adsorbed in the pores show classic, layer-by-layer film growth as a function of pore filling, leaving the long range symmetry of the system intact. In contrast, the adsorption of He3-He4 mixtures produces a structure incommensurate with the pore lattice. Neither capillary condensation nor preferential adsorption of one helium isotope to the pore walls can provide the symmetry-breaking mechanism. The scattering is consistent with the formation of randomly distributed liquid-liquid microdomains ˜2.3nm in size, providing evidence that confinement in a nanometer scale capillary can drive local phase separation in quantum liquid mixtures.

Active damping of capillary oscillations on liquid columns

NASA Astrophysics Data System (ADS)

Thiessen, David B.; Wei, Wei; Marston, Philip L.

2002-05-01

Active control of acoustic radiation pressure and of electrostatic stresses on liquid columns has been demonstrated to overcome the Rayleigh-Plateau instability that normally causes long liquid columns to break [M. J. Marr-Lyon et al., J. Fluid Mech. 351, 345 (1997); Phys. Fluids 12, 986-995 (2000)]. Though originally demonstrated for liquid-liquid systems in plateau tanks, the electrostatic method also works on columns in air in reduced gravity [D. B. Thiessen, M. J. Marr-Lyon, and P. L. Marston, ``Active electrostatic stabilization of liquid bridges in low gravity,'' J. Fluid Mech. (in press)]. In new research, the electrostatic stresses are applied in proportion to the velocity of the surface of the column so as to actively dampen capillary oscillations of the surface. The mode amplitude is optically sensed and the rate-of-change is electronically determined. Plateau tank measurements and theory both show that the change in damping rate is proportional to the feedback gain. The results suggest that either active control of electrostatic stresses or of acoustic radiation stresses can be used to suppress the response of interfaces to vibration. [Work supported by NASA.

Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid

NASA Astrophysics Data System (ADS)

Roy, James W.; Smith, James E.

2007-01-01

Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

Multiphase flow and transport caused by spontaneous gas phase growth in the presence of dense non-aqueous phase liquid.

PubMed

Roy, James W; Smith, James E

2007-01-30

Disconnected bubbles or ganglia of trapped gas may occur below the top of the capillary fringe through a number of mechanisms. In the presence of dense non-aqueous phase liquid (DNAPL), the disconnected gas phase experiences mass transfer of dissolved gases, including volatile components from the DNAPL. The properties of the gas phase interface can also change. This work shows for the first time that when seed gas bubbles exist spontaneous gas phase growth can be expected to occur and can significantly affect water-gas-DNAPL distributions, fluid flow, and mass transfer. Source zone behaviour was observed in three different experiments performed in a 2-dimensional flow cell. In each case, a DNAPL pool was created in a zone of larger glass beads over smaller glass beads, which served as a capillary barrier. In one experiment effluent water samples were analyzed to determine the vertical concentration profile of the plume above the pool. The experiments effectively demonstrated a) a cycle of spontaneous gas phase expansion and vertical advective mobilization of gas bubbles and ganglia above the DNAPL source zone, b) DNAPL redistribution caused by gas phase growth and mobilization, and c) that these processes can significantly affect mass transport from a NAPL source zone.

The cellular lesion of humoral rejection: predominant recruitment of monocytes to peritubular and glomerular capillaries.

PubMed

Fahim, T; Böhmig, G A; Exner, M; Huttary, N; Kerschner, H; Kandutsch, S; Kerjaschki, D; Bramböck, A; Nagy-Bojarszky, K; Regele, H

2007-02-01

Accumulation of inflammatory cells within capillaries is a common morphologic feature of humoral renal allograft rejection and is most easily appreciated if it occurs in glomeruli. The aim of our study was to determine the amount and composition of immune cells within glomeruli and peritubular capillaries (PTC) in cellular and humoral allograft rejection. Immunofluorescent double-labeling for CD31 and CD3 or CD68 was used for phenotyping and enumerating immune cells within glomeruli and PTC. The major findings are: (1) accumulation of immune cells in PTC is far more common than it would be anticipated based on the assessment by conventional histology; (2) it is not the absolute number of immune cells accumulating within capillaries, but rather the composition of the intracapillary cell population that distinguishes humoral rejection from cellular rejection and (3) in C4d positive biopsies a predominantly monocytic cell population accumulates not only within glomeruli but also within PTC. The median value of monocyte/T-cell ratio within PTC was 2.3 in C4d positive biopsies but only 1 (p = 0.0008) in C4d negative biopsies. Given their prominent presence within capillaries and their extensive biological versatility monocytes might contribute to the capillary damage observed in acute and chronic allograft rejection.

Visual observation of gas hydrates nucleation and growth at a water - organic liquid interface

NASA Astrophysics Data System (ADS)

Stoporev, Andrey S.; Semenov, Anton P.; Medvedev, Vladimir I.; Sizikov, Artem A.; Gushchin, Pavel A.; Vinokurov, Vladimir A.; Manakov, Andrey Yu.

2018-03-01

Visual observation of nucleation sites of methane and methane-ethane-propane hydrates and their further growth in water - organic liquid - gas systems with/without surfactants was carried out. Sapphire Rocking Cell RCS6 with transparent sapphire cells was used. The experiments were conducted at the supercooling ΔTsub = 20.2 °C. Decane, toluene and crude oils were used as organics. Gas hydrate nucleation occurred on water - metal - gas and water - sapphire - organic liquid three-phase contact lines. At the initial stage of growth hydrate crystals rapidly covered the water - gas or water - organics interfaces (depending on the nucleation site). Further hydrate phase accrete on cell walls (sapphire surface) and into the organics volume. At this stage, growth was accompanied by water «drawing out» from under initial hydrate film formed at water - organic interface. Apparently, it takes place due to water capillary inflow in the reaction zone. It was shown that the hydrate crystal morphology depends on the organic phase composition. In the case of water-in-decane emulsion relay hydrate crystallization was observed in the whole sample, originating most likely due to the hydrate crystal intergrowth through decane. Contacts of such crystals with adjacent water droplets result in rapid hydrate crystallization on this droplet.

Capillary electrophoresis coupled with mass spectrometry for the evaluation of substance P enzymatic degradation by SaOS-2 human osteosarcoma.

PubMed

Cavazza, Antonella; Corradini, Claudio; Marini, Mario; Roda, Luigi Giorgio; Valenti, Angela

2011-09-01

A new analytical method for the detection and the quantitative evaluation of the undecapeptide substance P by capillary electrophoresis coupled with ion trap mass spectrometry (CE-MS) by a co-axial sheath liquid interface has been developed. Conditions of analysis employed an acidic buffer and a 60 cm fused silica capillary installed by overcoming the UV window position, thus allowing to perform the analysis in a brief time. The method has been applied to the evaluation of substance P enzymatic hydrolysis during incubation with the human osteosarcoma SaOS-2 cell line. The analysis of amino acids derived from the cleavage of substance P has been also carried out simultaneously under the same electrophoretic conditions allowing the description of a kinetic of amino acid formation, parallel with substance P disappearance. The amounts of intact substance P and of free amino acids were monitored along 600 s of incubation time. A steady decrease of substance P as function of reaction time was observed. Peptide's half-life was found to be about 4.3s, indicating an extremely fast hydrolysis in the presence of the SaOS-2 cells. Proline, phenilalanine and methionine were the predominant free amino acids recorded. Obtained results lead to hypothesize the occurrence of endopeptidases activity, followed by aminopeptidases responsible for the release of free amino acids originated after primary bond cleavage. Copyright © 2011 Elsevier B.V. All rights reserved.

Interfacial bubbles formed by plunging thin liquid films in a pool

NASA Astrophysics Data System (ADS)

Salkin, Louis; Schmit, Alexandre; David, Richard; Delvert, Alexandre; Gicquel, Eric; Panizza, Pascal; Courbin, Laurent

2017-06-01

We show that the immersion of a horizontally suspended thin film of liquid in a pool of the same fluid creates an interfacial bubble, that is, a bubble at the liquid-air interface. Varying the fluid properties, the film's size, and its immersion velocity, our experiments unveil two formation regimes characterized by either a visco-capillary or an inertio-capillary mechanism that controls the size of a produced bubble. To rationalize these results, we compare the pressure exerted by the air flow under a plunging film with the Laplace pressure needed to generate film dimpling, which subsequently yields air entrapment and the production of a bubble. This physical model explains the power-law variations of the bubble size with the governing dimensionless number for each regime.

Absorbance and fluorometric sensing with capillary wells microplates.

PubMed

Tan, Han Yen; Cheong, Brandon Huey-Ping; Neild, Adrian; Liew, Oi Wah; Ng, Tuck Wah

2010-12-01

Detection and readout from small volume assays in microplates are a challenge. The capillary wells microplate approach [Ng et al., Appl. Phys. Lett. 93, 174105 (2008)] offers strong advantages in small liquid volume management. An adapted design is described and shown here to be able to detect, in a nonimaging manner, fluorescence and absorbance assays minus the error often associated with meniscus forming at the air-liquid interface. The presence of bubbles in liquid samples residing in microplate wells can cause inaccuracies. Pipetting errors, if not adequately managed, can result in misleading data and wrong interpretations of assay results; particularly in the context of high throughput screening. We show that the adapted design is also able to detect for bubbles and pipetting errors during actual assay runs to ensure accuracy in screening.

Star-shaped oscillations of Leidenfrost drops

NASA Astrophysics Data System (ADS)

Ma, Xiaolei; Liétor-Santos, Juan-José; Burton, Justin C.

2017-03-01

We experimentally investigate the self-sustained, star-shaped oscillations of Leidenfrost drops. The drops levitate on a cushion of evaporated vapor over a heated, curved surface. We observe modes with n =2 -13 lobes around the drop periphery. We find that the wavelength of the oscillations depends only on the capillary length of the liquid and is independent of the drop radius and substrate temperature. However, the number of observed modes depends sensitively on the liquid viscosity. The dominant frequency of pressure variations in the vapor layer is approximately twice the drop oscillation frequency, consistent with a parametric forcing mechanism. Our results show that the star-shaped oscillations are driven by capillary waves of a characteristic wavelength beneath the drop and that the waves are generated by a large shear stress at the liquid-vapor interface.

Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

PubMed Central

Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

2016-01-01

Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

Investigating the time-dependent zeta potential of wood surfaces.

PubMed

Muff, Livius F; Luxbacher, Thomas; Burgert, Ingo; Michen, Benjamin

2018-05-15

This work reports on streaming potential measurements through natural capillaries in wood and investigates the cause of a time-dependent zeta potential measured during the equilibration of wood cell-walls with an electrolyte solution. For the biomaterial, this equilibration phase takes several hours, which is much longer than for many other materials that have been characterized by electrokinetic measurements. During this equilibration phase the zeta potential magnitude is decaying due to two parallel mechanisms: (i) the swelling of the cell-wall which causes a dimensional change reducing the charge density at the capillary interface; (ii) the transport of ions from the electrolyte solution into the permeable cell-wall which alters the electrical potential at the interface by internal charge compensation. The obtained results demonstrate the importance of equilibration kinetics for an accurate determination of the zeta potential, especially for materials that interact strongly with the measurement electrolyte. Moreover, the change in zeta potential with time can be correlated with the bulk swelling of wood if the effect of electrolyte ion diffusion is excluded. This study shows the potential of streaming potential measurements of wood, and possibly of other hygroscopic and nanoporous materials, to reveal kinetic information about their interaction with liquids, such as swelling and ion uptake. Copyright © 2018 Elsevier Inc. All rights reserved.

Vibration isolation technology: Sensitivity of selected classes of experiments to residual accelerations

NASA Technical Reports Server (NTRS)

Alexander, J. Iwan D.

1991-01-01

Work was completed on all aspects of the following tasks: order of magnitude estimates; thermo-capillary convection - two-dimensional (fixed planar surface); thermo-capillary convection - three-dimensional and axisymmetric; liquid bridge/floating zone sensitivity; transport in closed containers; interaction: design and development stages; interaction: testing flight hardware; and reporting. Results are included in the Appendices.

Capillary Suction Time. Operational Control Tests for Wastewater Treatment Facilities. Instructor's Manual [and] Student Workbook.

ERIC Educational Resources Information Center

Wooley, John F.

Capillary suction time is time required for the liquid phase of a treated sludge to travel through 1 centimeter of media (blotter or filter paper). Designed for individuals who have completed National Pollutant Discharge Elimination System (NPDES) level 1 laboratory training skills, this module provides waste water treatment plant operators with…

Conditions for fluid separations in microchannels, capillary-driven fluid separations, and laminated devices capable of separating fluids

DOEpatents

TeGrotenhuis, Ward E [Kennewick, WA; Stenkamp, Victoria S [Richland, WA

2005-04-05

Methods of separating fluids using capillary forces and/or improved conditions for are disclosed. The improved methods may include control of the ratio of gas and liquid Reynolds numbers relative to the Suratman number. Also disclosed are wick-containing, laminated devices that are capable of separating fluids.

Conditions for fluid separations in microchannels, capillary-driven fluid separations, and laminated devices capable of separating fluids

DOEpatents

TeGrotenhuis, Ward E [Kennewick, WA; Stenkamp, Victoria S [Richland, WA

2008-03-18

Methods of separating fluids using capillary forces and/or improved conditions for are disclosed. The improved methods may include control of the ratio of gas and liquid Reynolds numbers relative to the Suratman number. Also disclosed are wick-containing, laminated devices that are capable of separating fluids.

Quantitative fine structure of capillaries in subregions of the rat subfornical organ.

PubMed

Shaver, S W; Sposito, N M; Gross, P M

1990-04-01

The differentiated cytology across subregions of the rat subfornical organ (SFO) prompted our hypothesis that ultrastructural features of capillary endothelial cells would vary topographically and quantitatively within this small nucleus. We used electron microscopic and computer-based morphometric methods to assess fine structural dimensions of the capillary endothelium in four distinct subregions of the SFO from Long-Evans and homozygous Brattleboro rats. Three types of capillary were present. Type III capillaries (resembling those of endocrine glands) had an average wall thickness of 0.17 microns, 54% thinner than those of Type I and II capillaries. Pericapillary spaces around Type III capillaries measured 56 microns2, 100% larger than for Type I vessels (resembling those of skeletal muscle). Only Type III capillaries contained fenestrations (9 per microns2 of endothelial cell) and were the predominant type of capillary in central and caudal subregions of the SFO. Type I capillaries, prevalent in the transitional subregion between the central and rostral parts of the SFO, had 10 cytoplasmic vesicles per micron2 of endothelial cell area, a number not different from that of Type III capillaries but 3x the frequency found in Type II vessels. Type II capillaries (those typical of "blood-brain barrier" endothelium) had low vesicular density (3 per microns2), no fenestrations, and no pericapillary spaces. Luminal diameters and the densities of mitochondria and intercellular junctions were not different among capillary types or subregions in the SFO. Furthermore, there were no morphometric differences for any capillary dimensions between Long-Evans and Brattleboro rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Coupling of small, low-loss hexapole mode with photonic crystal slab waveguide mode.

PubMed

Kim, Guk-Hyun; Lee, Yong-Hee; Shinya, Akihiko; Notomi, Masaya

2004-12-27

Coupling characteristics between the single-cell hexapole mode and the triangular-lattice photonic crystal slab waveguide mode is studied by the finite-difference time-domain method. The single-cell hexapole mode has a high quality factor (Q) of 3.3Chi106 and a small modal volume of 1.18(lambda/n)3. Based on the symmetry, three representative types of coupling geometries (shoulder-couple, butt-couple and side-couple structures) are selected and tested. The coupling efficiency shows strong dependence on the transverse overlap of the cavity mode and the waveguide mode over the region of the waveguide. The shoulder-couple structure shows best coupling characteristics among three tested structures. For example, two shouldercouple waveguides and a hexapole cavity result in a high performance resonant-tunneling-filter with Q of 9.7Chi105 and transmittance of 0.48. In the side-couple structure, the coupling strength is much weaker than that of the shoulder-couple structure because of the poor spatial overlap between the mode profiles. In the direct-couple structure, the energy transfer from the cavity to the waveguide is prohibited because of the symmetry mismatch and no coupling is observed.

Spray-loading: A cryogenic deposition method for diamond anvil cell

NASA Astrophysics Data System (ADS)

Scelta, Demetrio; Ceppatelli, Matteo; Ballerini, Riccardo; Hajeb, Ahmed; Peruzzini, Maurizio; Bini, Roberto

2018-05-01

An efficient loading technique has been developed for flammable, toxic, or explosive gases which can be condensed at liquid nitrogen temperature and ambient pressure in membrane diamond anvil cells (DACs). This cryogenic technique consists in a deposition of small quantities of the desired gas directly into the sample chamber. The deposition is performed using a capillary that reaches the space between the diamond anvils. The DAC is kept under inert gas overpressure during the whole process, in order to avoid contamination from atmospheric O2, CO2, and H2O. This technique provides significant advantages over standard cryo-loading and gas-loading when the condensation of dangerous samples at liquid nitrogen temperature raises safety concerns because it allows dealing with minimum quantities of condensed gases. The whole procedure is particularly fast and efficient. The "spray-loading" has been successfully used in our laboratory to load several samples including acetylene, ammonia, ethylene, and carbon dioxide/water or red phosphorus/NH3 mixtures.

Industrial Raman gas sensing for real-time system control

NASA Astrophysics Data System (ADS)

Buric, M.; Mullen, J.; Chorpening, B.; Woodruff, S.

2014-06-01

Opportunities exist to improve on-line process control in energy applications with a fast, non-destructive measurement of gas composition. Here, we demonstrate a Raman sensing system which is capable of reporting the concentrations of numerous species simultaneously with sub-percent accuracy and sampling times below one-second for process control applications in energy or chemical production. The sensor is based upon a hollow-core capillary waveguide with a 300 micron bore with reflective thin-film metal and dielectric linings. The effect of using such a waveguide in a Raman process is to integrate Raman photons along the length of the sample-filled waveguide, thus permitting the acquisition of very large Raman signals for low-density gases in a short time. The resultant integrated Raman signals can then be used for quick and accurate analysis of a gaseous mixture. The sensor is currently being tested for energy applications such as coal gasification, turbine control, well-head monitoring for exploration or production, and non-conventional gas utilization. In conjunction with an ongoing commercialization effort, the researchers have recently completed two prototype instruments suitable for hazardous area operation and testing. Here, we report pre-commercialization testing of those field prototypes for control applications in gasification or similar processes. Results will be discussed with respect to accuracy, calibration requirements, gas sampling techniques, and possible control strategies of industrial significance.

Ultra-high-stability, pH-resistant sol-gel titania poly(tetrahydrofuran) coating for capillary microextraction on-line coupled to high-performance liquid chromatography.

PubMed

Segro, Scott S; Cabezas, Yaniel; Malik, Abdul

2009-05-15

A sol-gel titania poly(tetrahydrofuran) (poly-THF) coating was developed for capillary microextraction hyphenated on-line with high-performance liquid chromatography (HPLC). Poly-THF was covalently bonded to the sol-gel titania network which, in turn, became chemically anchored to the inner surface of a 0.25mm I.D. fused silica capillary. For sample preconcentration, a 38-cm segment of the sol-gel titania poly-THF coated capillary was installed on an HPLC injection port as a sampling loop. Aqueous samples containing a variety of analytes were passed through the capillary and, during this process, the analytes were extracted by the sol-gel titania poly-THF coating on the inner surface of the capillary. Using isocratic and gradient elution with acetonitrile/water mobile phases, the extracted analytes were desorbed into the on-line coupled HPLC column for separation and UV detection. The sol-gel titania poly-THF coating was especially efficient in extracting polar analytes, such as underivatized phenols, alcohols, amines, and aromatic carboxylic acids. In addition, this coating was capable of extracting moderately polar and nonpolar analytes, such as ketones and polycyclic aromatic hydrocarbons. The sol-gel titania poly-THF coated capillary was also able to extract polypeptides at pH values near their respective isoelectric points. Extraction of these compounds can be important for environmental and biomedical applications. The observed extraction behavior can be attributed to the polar and nonpolar moieties in the poly-THF structure. This coating was found to be stable under extremely low and high pH conditions-even after 18h of exposure to 1M HCl (pH approximately 0.0) and 1M NaOH (pH approximately 14.0).

Electro-optical phenomena based on ionic liquids in an optofluidic waveguide.

PubMed

He, Xiaodong; Shao, Qunfeng; Cao, Pengfei; Kong, Weijie; Sun, Jiqian; Zhang, Xiaoping; Deng, Youquan

2015-03-07

An optofluidic waveguide with a simple two-terminal electrode geometry, when filled with an ionic liquid (IL), forms a lateral electric double-layer capacitor under a direct current (DC) electric field, which allows the realization of an extremely high carrier density in the vicinity of the electrode surface and terminals to modulate optical transmission at room temperature under low voltage operation (0 to 4 V). The unique electro-optical phenomenon of ILs was investigated at three wavelengths (663, 1330 and 1530 nm) using two waveguide geometries. Strong electro-optical modulations with different efficiencies were observed at the two near-infrared (NIR) wavelengths, while no detectable modulation was observed at 663 nm. The first waveguide geometry was used to investigate the position-dependent modulation along the waveguide; the strongest modulation was observed in the vicinity of the electrode terminal. The modulation phase is associated with the applied voltage polarity, which increases in the vicinity of the negative electrode and decreases at the positive electrode. The second waveguide geometry was used to improve the modulation efficiency. Meanwhile, the electro-optical modulations of seven ILs were compared at an applied voltage ranging from ±2 V to ±3.5 V. The results reveal that the modulation amplitude and response speed increase with increasing applied voltage, as well as the electrical conductivity of ILs. Despite the fact that the response speed isn't fast due to the high ionic density of ILs, the modulation amplitude can reach up to 6.0 dB when a higher voltage (U = ±3.5 V) is applied for the IL [Emim][BF4]. Finally, the physical explanation of the phenomenon was discussed. The effect of the change in IL structure on the electro-optical phenomena was investigated in another new experiment. The results reveal that the electro-optical phenomenon is probably caused mainly by the change in carrier concentration (ion redistribution near charged electrodes), which induces the enhancement and suppression of NIR optical absorption (contributed by C-H and N-H groups) in the vicinity of the negative electrode and positive electrode, respectively.

A Zero-Gravity Cup for Drinking Beverages in Microgravity

NASA Technical Reports Server (NTRS)

Pettit, Donald R.; Weislogel, Mark; Concus, Paul; Finn, Robert

2011-01-01

To date, the method for astronauts to drink liquids in microgravity or weightless environments is to suck the liquid from a bag or pouch through a straw. A new beverage cup works in microgravity and allows astronauts to drink liquids from a cup in a manner consistent with that on Earth. The cup is capable of holding beverages with an angled channel running along the wall from the bottom to the lip. In microgravity, a beverage is placed into the cup using the galley dispenser. The angled channel acts as an open passage that contains only two sides where capillary forces move the liquid along the channel until it reaches the top lip where the forces reach an equilibrium and the flow stops. When one sips the liquid at the lip of the channel, the capillary force equilibrium is upset and more liquid flows to the lip from the reservoir at the bottom to re-establish the equilibrium. This sipping process can continue until the total liquid contents of the cup is consumed, leaving only a few residual drops about the same quantity as in a ceramic cup when it is drunk dry on Earth.

Er:YAG delamination of immersed biological membranes using sealed flexible hollow waveguides

NASA Astrophysics Data System (ADS)

Sagi-Dolev, A. M.; Dror, Jacob; Inberg, Alexandra; Ferencz, J. R.; Croitoru, Nathan I.

1996-04-01

The radiation of Er-YAG laser ((lambda) equals 2.94 micrometer) gives selective interaction with tissues. The extinction in soft tissues is only a few micrometers and in hard tissues is of the order of hundreds of micrometers. This makes this type of laser very suitable for treatments in dentistry, orthopedy, or ophthalmology. Because the usual silica fibers are not transmitting the radiation at lambda equals 2.94 micrometer of this laser, many applications cannot be presently performed. Fused silica hollow fibers for Er-YAG radiation were developed in our laboratory and several possible applications in dentistry, orthopedy and ophthalmology were indicated. Hole opening and implantation preparation of teeth were experimented, using Er-YAG laser and hollow plastic waveguide delivery systems. Hole drilling in cow bones was demonstrated for applications in orthopedy. A new procedure of delivering Er-YAG radiation on fibrotic membranes of inner eggshell as a model of the membranes in eyes was developed employing silica hollow waveguides of 0.5 and 0.7 mm ID or a plastic waveguide of 1.0 mm ID. For this purpose waveguides with sealed distal tip were employed to enable us to approach the delivery system through liquid media near to the membrane. This experiment demonstrates the possibility of surgical applications in vitectomy in ophthalmology using Er-YAG laser and silica hollow waveguides.

Traveling wave linear accelerator with RF power flow outside of accelerating cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgashev, Valery A.

A high power RF traveling wave accelerator structure includes a symmetric RF feed, an input matching cell coupled to the symmetric RF feed, a sequence of regular accelerating cavities coupled to the input matching cell at an input beam pipe end of the sequence, one or more waveguides parallel to and coupled to the sequence of regular accelerating cavities, an output matching cell coupled to the sequence of regular accelerating cavities at an output beam pipe end of the sequence, and output waveguide circuit or RF loads coupled to the output matching cell. Each of the regular accelerating cavities hasmore » a nose cone that cuts off field propagating into the beam pipe and therefore all power flows in a traveling wave along the structure in the waveguide.« less

Angiogenesis and phenotypic alteration of alveolar capillary endothelium in areas of neoplastic cell spread in primary lung adenocarcinoma.

PubMed

Jin, E; Ghazizadeh, M; Fujiwara, M; Nagashima, M; Shimizu, H; Ohaki, Y; Arai, S; Gomibuchi, M; Takemura, T; Kawanami, O

2001-09-01

Normal alveolar capillary endothelium is quiescent in nature and displays anticoagulant thrombomodulin (TM) on its surface. The cytoplasms of these endothelial cells are ultrastructurally non-fenestrated type, and they barely express von Willebrand factor (vWf). Alveolar fibrosis is accompanied by a capillary endothelium reactive for vWf, and a loss of TM expression. In primary lung adenocarcinoma, neovascularization occurs in association with alveolar fibrosis. In order to study basic factors related to angiogenesis and phenotypic changes of the capillaries located in tumor-bearing alveolar walls, we examined 37 primary lung adenocarcinomas with electron microscopy and confocal laser scanning microscopy with antibodies for TM, vWf, vascular endothelial growth factor (VEGF), and its receptors (KDR and Flt-1), and proliferating markers (Ki-67/proliferating cell nuclear antigen). Tissues microdissected specifically from alveolar walls were used for reverse transcription-polymerase chain reaction (RT-PCR) to assess expressions of mRNA isoforms of VEGF and its receptors. New capillary branching was found by ultrastructural study in the alveolar walls in 12% of the patients. Nuclei of the capillary endothelial cells were reactive for proliferating cell markers. Endothelial fenestrae were developed in 65% of the patients, TM reactivity was lost in the alveolar capillaries, and their cell cytoplasms obtained a reactivity for vWf through a transitional mosaic-like distribution pattern of both antigens. Besides cytoplasmic VEGF expression in neoplastic cells, tumor-bearing alveolar walls showed significant expression of mRNA of VEGF165 and KDR. These findings imply that angiogenesis and phenotypic changes of the alveolar capillaries are closely related to a higher expression of tumor-associated VEGF165 and of KDR in the alveolar walls in primary lung adenocarcinoma.

A study of the rheological properties of endodontic sealers.

PubMed

Lacey, S; Pitt Ford, T R; Watson, T F; Sherriff, M

2005-08-01

To test the hypothesis that there would be no statistically significant difference in viscosity-related measures of endodontic sealers or change in these with strain rate, internal diameter or powder : liquid ratio in a capillary system. Materials used were Apexit, Tubliseal EWT, Grossman's sealer and Ketac-endo. Viscosity-related measures were tested in a two-plate test, and in a capillary rheometer. The mean values (n = 12) for thickness and diameter of material formed between two glass plates were tested with one-way analysis of variance. Pressure was applied to a capillary rheometer at strain rates 5 and 10 mm min(-1) in tubes of internal diameter 0.6 and 1.2 mm. Tubliseal EWT had a thinner film thickness than the other sealers (alpha = 0.05). The difference in diameter between Tubliseal EWT and the other sealers was significant apart from Apexit. Increased strain rate gave a significant increase (alpha = 0.05) in the flow of all sealers. Narrower tubes produced increased velocity, which was significant for all sealers, and reduced volumetric flow, which was significant for all sealers except Grossman's 2 : 1 (Wilcoxon signed rank test). Reduction in powder : liquid ratio of Grossman's significantly increased flow in narrow tubes and at higher strain rate (Mann-Whitney test). There was a significant difference between the flow of Tubliseal EWT and the other sealers tested in the two-plate test; capillary flow was affected by sealer, internal diameter, strain rate and powder : liquid ratio. The null hypotheses were rejected.

Investigation of the role of the micro-porous layer in polymer electrolyte fuel cells with hydrogen deuterium contrast neutron radiography.

PubMed

Cho, Kyu Taek; Mench, Matthew M

2012-03-28

In this study, the high resolution hydrogen-deuterium contrast radiography method was applied to elucidate the impact of the micro-porous layer (MPL) on water distribution in the porous fuel cell media. At the steady state, deuterium replaced hydrogen in the anode stream, and the large difference in neutron attenuation of the D(2)O produced at the cathode was used to track the produced water. It was found that the water content peaked in the cathode-side diffusion media (DM) for the cell without MPL, but with an MPL on the anode and cathode DM, the peak water amount was pushed toward the anode, resulting in a relatively flattened water profile through components and demonstrating a liquid barrier effect. Additionally, the dynamic water behavior in diffusion media was analyzed to understand the effect of a MPL and operating conditions. The water content in the DM changed with applied current, although there is a significant amount of residual liquid content that does not appear to be part of capillary channels. The effect of the MPL on irreducible saturation in DM and cell performance was also investigated.

Extracellular matrix and cell shape: potential control points for inhibition of angiogenesis

NASA Technical Reports Server (NTRS)

Ingber, D.

1991-01-01

Capillary endothelial (CE) cells require two extracellular signals in order to switch from quiescence to growth and back to differentiation during angiogenesis: soluble angiogenic factors and insoluble extracellular matrix (ECM) molecules. Soluble endothelial mitogens, such as basic fibroblast growth factor (FGF), act over large distances to trigger capillary growth, whereas ECM molecules act locally to modulate cell responsiveness to these soluble cues. Recent studies reveal that ECM molecules regulate CE cell growth and differentiation by modulating cell shape and by activating intracellular chemical signaling pathways inside the cell. Recognition of the importance of ECM and cell shape during capillary morphogenesis has led to the identification of a series of new angiogenesis inhibitors. Elucidation of the molecular mechanism of capillary regulation may result in development of even more potent angiogenesis modulators in the future.

Capillary droplet propulsion on a fibre.

PubMed

Haefner, Sabrina; Bäumchen, Oliver; Jacobs, Karin

2015-09-21

A viscous liquid film coating a fibre becomes unstable and decays into droplets due to the Rayleigh-Plateau instability (RPI). Here, we report on the generation of uniform droplets on a hydrophobized fibre by taking advantage of this effect. In the late stages of liquid column breakup, a three-phase contact line can be formed at one side of the droplet by spontaneous rupture of the thinning film. The resulting capillary imbalance leads to droplet propulsion along the fibre. We study the dynamics and the dewetting speed of the droplet as a function of molecular weight as well as temperature and compare to a force balance model based on purely viscous dissipation.

Curvature-induced capillary interaction of spherical particles at a liquid interface.

PubMed

Würger, Alois

2006-10-01

We consider a liquid interface with different principal curvatures +/-c and find that the mere presence of a spherical particle leads to a deformation field of quadrupolar symmetry; the corresponding "capillary quadrupole moment" is given by the ratio of the particle size and the curvature radius. The resulting pair interaction of nearby particles is anisotropic and favors the formation of aggregates of cubic symmetry. Since the single-particle trapping energy depends quadratically on curvature with a negative prefactor, a curvature gradient induces a lateral force that pushes the particles towards strongly curved regions of the interface. As an illustration we discuss the effects occurring on a catenoid.

Particle-in-cell simulation of multipactor discharge on a dielectric in a parallel-plate waveguide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakharov, A. S., E-mail: sakharov-as@mail.ru; Ivanov, V. A.; Konyzhev, M. E.

2016-06-15

An original 2D3V (two-dimensional in coordinate space and three-dimensional in velocity space) particle-in-cell code has been developed for simulation of multipactor discharge on a dielectric in a parallelplate metal waveguide with allowance for secondary electron emission (SEE) from the dielectric surface and waveguide walls, finite temperature of secondary electrons, electron space charge, and elastic and inelastic scattering of electrons from the dielectric and metal surfaces. The code allows one to simulate all stages of the multipactor discharge, from the onset of the electron avalanche to saturation. It is shown that the threshold for the excitation of a single-surface multipactor onmore » a dielectric placed in a low-profile waveguide with absorbing walls increases as compared to that in the case of an unbounded dielectric surface due to escape of electrons onto the waveguide walls. It is found that, depending on the microwave field amplitude and the SEE characteristics of the waveguide walls, the multipactor may operate in two modes. In the first mode, which takes place at relatively low microwave amplitudes, a single-surface multipactor develops only on the dielectric, the surface of which acquires a positively potential with respect to the waveguide walls. In the second mode, which occurs at sufficiently high microwave intensities, a single-surface multipactor on the dielectric and a two-surface multipactor between the waveguide walls operate simultaneously. In this case, both the dielectric surface and the interwall space acquire a negative potential. It is shown that electron scattering from the dielectric surface and waveguide walls results in the appearance of high-energy tails in the electron distribution function.« less

Capillary Liquid Acquisition Device Heat Entrapment

NASA Technical Reports Server (NTRS)

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

2007-01-01

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

Advanced proteomic liquid chromatography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xie, Fang; Smith, Richard D.; Shen, Yufeng

2012-10-26

Liquid chromatography coupled with mass spectrometry is the predominant platform used to analyze proteomics samples consisting of large numbers of proteins and their proteolytic products (e.g., truncated polypeptides) and spanning a wide range of relative concentrations. This review provides an overview of advanced capillary liquid chromatography techniques and methodologies that greatly improve separation resolving power and proteomics analysis coverage, sensitivity, and throughput.

Packaged integrated opto-fluidic solution for harmful fluid analysis

NASA Astrophysics Data System (ADS)

Allenet, T.; Bucci, D.; Geoffray, F.; Canto, F.; Couston, L.; Jardinier, E.; Broquin, J.-E.

2016-02-01

Advances in nuclear fuel reprocessing have led to a surging need for novel chemical analysis tools. In this paper, we present a packaged lab-on-chip approach with co-integration of optical and micro-fluidic functions on a glass substrate as a solution. A chip was built and packaged to obtain light/fluid interaction in order for the entire device to make spectral measurements using the photo spectroscopy absorption principle. The interaction between the analyte solution and light takes place at the boundary between a waveguide and a fluid micro-channel thanks to the evanescent part of the waveguide's guided mode that propagates into the fluid. The waveguide was obtained via ion exchange on a glass wafer. The input and the output of the waveguides were pigtailed with standard single mode optical fibers. The micro-scale fluid channel was elaborated with a lithography procedure and hydrofluoric acid wet etching resulting in a 150+/-8 μm deep channel. The channel was designed with fluidic accesses, in order for the chip to be compatible with commercial fluidic interfaces/chip mounts. This allows for analyte fluid in external capillaries to be pumped into the device through micro-pipes, hence resulting in a fully packaged chip. In order to produce this co-integrated structure, two substrates were bonded. A study of direct glass wafer-to-wafer molecular bonding was carried-out to improve detector sturdiness and durability and put forward a bonding protocol with a bonding surface energy of γ>2.0 J.m-2. Detector viability was shown by obtaining optical mode measurements and detecting traces of 1.2 M neodymium (Nd) solute in 12+/-1 μL of 0.01 M and pH 2 nitric acid (HNO3) solvent by obtaining an absorption peak specific to neodymium at 795 nm.

High Concentrating GaAs Cell Operation Using Optical Waveguide Solar Energy System

NASA Technical Reports Server (NTRS)

Nakamura, T.; Case, J. A.; Timmons, M. L.

2004-01-01

This paper discusses the result of the concentrating photovoltaic (CPV) cell experiments conducted with the Optical Waveguide (OW) Solar Energy System. The high concentration GaAs cells developed by Research Triangle Institute (RTI) were combined with the OW system in a "fiber-on-cell" configuration. The sell performance was tested up to the solar concentration of 327. Detailed V-I characteristics, power density and efficiency data were collected. It was shown that the CPV cells combined with the OW solar energy system will be an effective electric power generation device.

Probing the liquid crystal alignment interface and switching dynamics in a slab waveguide architecture

NASA Astrophysics Data System (ADS)

Gotjen, Henry G.; Kolacz, Jakub; Myers, Jason D.; Frantz, Jesse A.; Bekele, Robel Y.; Naciri, Jawad; Spillmann, Christopher M.

2018-02-01

A non-mechanical refractive laser beam steering device has been developed to provide continuous, two-dimensional steering of infrared beams. The technology implements a dielectric slab waveguide architecture with a liquid crystal (LC) cladding. With voltage control, the birefringence of the LC can be leveraged to tune the effective index of the waveguide under an electrode. With a clever prism electrode design a beam coupled into the waveguide can be deflected continuously in two dimensions as it is coupled out into free space. The optical interaction with LC in this beamsteerer is unique from typical LC applications: only the thin layer of LC (100s of nm) near the alignment interface interacts with the beam's evanescent field. Whereas most LC interactions take place over short path lengths (microns) in the bulk of the material, here we can interrogate the behavior of LC near the alignment interface over long path lengths (centimeters). In this work the beamsteerer is leveraged as a tool to study the behavior of LC near the alignment layer in contrast to the bulk material. We find that scattering is substantially decreased near the alignment interface due to the influence of the surface anchoring energy to suppress thermal fluctuations. By tracking the position of the deflected beam with a high speed camera, we measure response times of the LC near the interface in off-to-on switching ( ms) and on-to-off switching ( 100ms). Combined, this work will provide a path for improved alignment techniques, greater optical throughput, and faster response times in this unique approach to non-mechanical beamsteering.

New SPUDT cell structures.

PubMed

Martin, Guenter; Schmidt, Hagen; Wall, Bert

2004-07-01

The present paper describes single-phase unidirectional transducers (SPUDT) cells with all fingers wider than lambda/8 while maintaining the unidirectional effect. The first solution is related to a SPUDT consisting of lambda/4 and lambda/2 wide fingers arranged in two tracks. Each track has no significant unidirectional effect. Both tracks form a waveguide, and the waveguide coupling generates the interaction of the tracks. As a result of that interaction, a unidirectional effect arises as verified by experiment. This transducer type is called double-track (DT) SPUDT. A second solution is suggested that includes, in contrast to distributed acoustic reflection transducer (DART), electrode width control (EWC), and Hunsinger cells, SPUDT cell fingers with one and the same width only. Cell types with lambda/6, lambda/5, and lambda/3 wide fingers called uniform width electrode (UWE) cells are considered. One of these cell types, including exclusively lambda/5 wide fingers, is experimentally investigated and a unidirectional effect is found. Moreover, a filter example using the lambda/5 cell type has been designed for reducing SPUDT reflections. The echo suppression expected could be verified experimentally. No waveguide coupling is required for this cell type.

The measurement of solute diffusion coefficients in dilute liquid alloys: the influence of unit gravity and g-jitter on buoyancy convection.

PubMed

Smith, R W; Yang, B J; Huang, W D

2004-11-01

Liquid diffusion experiments conducted on the MIR space station using the Canadian Space Agency QUELD II processing facility and the microgravity isolation mount (MIM) showed that g-jitter significantly increased the measured solute diffusion coefficients. In some experiments, milli-g forced vibration was superimposed on the sample when isolated from the ambient g-jitter; this resulted in markedly increased solute transport. To further explore the effects arising in these long capillary diffusion couples from the absence of unit-gravity and the presence of the forced g-jitter, the effects of a 1 milli-g forcing vibration on the mass transport in a 1.5 mm diameter long capillary diffusion couple have been simulated. In addition, to increase understanding of the role of unit gravity in determining the extent to which gravity can influence measured diffusion coefficient values, comparative experiments involving gold, silver, and antimony diffusing in liquid lead have been carried out using a similar QUELD II facility to that employed in the QUELD II/MIM/MIR campaign but under terrestrial conditions. It was found that buoyancy-driven convection may still persist in the liquid even when conditions are arranged for a continuously decreasing density gradient up the axis of a vertical long capillary diffusion couple due to the presence of small radial temperature gradients.

Plethora of transitions during breakup of liquid filaments

DOE PAGES

Castrejón-Pita, José Rafael; Castrejón-Pita, Alfonso Arturo; Thete, Sumeet Suresh; ...

2015-03-30

Thinning and breakup of liquid filaments are central to dripping of leaky faucets, inkjet drop formation, and raindrop fragmentation. As the filament radius decreases, curvature and capillary pressure, both inversely proportional to radius, increase and fluid is expelled with increasing velocity from the neck. As the neck radius vanishes, the governing equations become singular and the filament breaks. In slightly viscous liquids, thinning initially occurs in an inertial regime where inertial and capillary forces balance. By contrast, in highly viscous liquids, initial thinning occurs in a viscous regime where viscous and capillary forces balance. As the filament thins, viscous forcesmore » in the former case and inertial forces in the latter become important, and theory shows that the filament approaches breakup in the final inertial–viscous regime where all three forces balance. However, previous simulations and experiments reveal that transition from an initial to the final regime either occurs at a value of filament radius well below that predicted by theory or is not observed. In this paper, we perform new simulations and experiments, and show that a thinning filament unexpectedly passes through a number of intermediate transient regimes, thereby delaying onset of the inertial–viscous regime. Finally, the new findings have practical implications regarding formation of undesirable satellite droplets and also raise the question as to whether similar dynamical transitions arise in other free-surface flows such as coalescence that also exhibit singularities.« less

Plethora of transitions during breakup of liquid filaments

PubMed Central

Castrejón-Pita, José Rafael; Castrejón-Pita, Alfonso Arturo; Thete, Sumeet Suresh; Sambath, Krishnaraj; Hutchings, Ian M.; Hinch, John; Lister, John R.; Basaran, Osman A.

2015-01-01

Thinning and breakup of liquid filaments are central to dripping of leaky faucets, inkjet drop formation, and raindrop fragmentation. As the filament radius decreases, curvature and capillary pressure, both inversely proportional to radius, increase and fluid is expelled with increasing velocity from the neck. As the neck radius vanishes, the governing equations become singular and the filament breaks. In slightly viscous liquids, thinning initially occurs in an inertial regime where inertial and capillary forces balance. By contrast, in highly viscous liquids, initial thinning occurs in a viscous regime where viscous and capillary forces balance. As the filament thins, viscous forces in the former case and inertial forces in the latter become important, and theory shows that the filament approaches breakup in the final inertial–viscous regime where all three forces balance. However, previous simulations and experiments reveal that transition from an initial to the final regime either occurs at a value of filament radius well below that predicted by theory or is not observed. Here, we perform new simulations and experiments, and show that a thinning filament unexpectedly passes through a number of intermediate transient regimes, thereby delaying onset of the inertial–viscous regime. The new findings have practical implications regarding formation of undesirable satellite droplets and also raise the question as to whether similar dynamical transitions arise in other free-surface flows such as coalescence that also exhibit singularities. PMID:25825761

Capillary electrophoresis coupled with chloroform-acetonitrile extraction for rapid and highly selective determination of cysteine and homocysteine levels in human blood plasma and urine.

PubMed

Ivanov, Alexander Vladimirovich; Bulgakova, Polina Olegovna; Virus, Edward Danielevich; Kruglova, Maria Petrovna; Alexandrin, Valery Vasil'evich; Gadieva, Viktoriya Aleksandrovna; Luzyanin, Boris Petrovich; Kushlinskii, Nikolai Evgen'evich; Fedoseev, Anatolij Nikolaevich; Kubatiev, Aslan Amirkhanovich

2017-10-01

A rapid and selective method has been developed for highly sensitive determination of total cysteine and homocysteine levels in human blood plasma and urine by capillary electrophoresis (CE) coupled with liquid-liquid extraction. Analytes were first derivatized with 1,1'-thiocarbonyldiimidazole and then samples were purified by chloroform-ACN extraction. Electrophoretic separation was performed using 0.1 M phosphate with 30 mM triethanolamine, pH 2, containing 25 μM CTAB, 2.5 μM SDS, and 2.5% polyethylene glycol 600. Samples were injected into the capillary (with total length 32 cm and 50 μm id) at 2250 mbar*s and subsequent injection was performed for 30 s with 0.5 M KОН. The total analysis time was less than 9 min, accuracy was 98%, and precision was <2.6%. The LOD was 0.2 μM for homocysteine and 0.5 μM for cysteine. The use of liquid-liquid extraction allowed the precision and sensitivity of the CE method to be significantly increased. The validated method was applied to determine total cysteine and homocysteine content in human blood plasma and urine samples obtained from healthy volunteers and patients with kidney disorders. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lysosomal Trapping Is Present in Retinal Capillary Endothelial Cells: Insight into Its Influence on Cationic Drug Transport at the Inner Blood-Retinal Barrier.

PubMed

Kubo, Yoshiyuki; Seko, Narumi; Usui, Takuya; Akanuma, Shin-Ichi; Hosoya, Ken-Ichi

2016-01-01

Lysosomal trapping was investigated in the retinal capillary endothelial cells that are responsible for the inner blood-retinal barrier (BRB) using LysoTracker(®) Red (LTR). Using confocal microscopy on TR-iBRB2 cells, an in vitro model of the inner BRB, the presence of lysosomal trapping in retinal capillary endothelial cells was suggested since TR-iBRB2 cells exhibited punctuate intracellular localization of LTR that was attenuated by NH4Cl treatment. The study confirmed that LTR uptake by retinal capillary endothelial cells took place in a time- and temperature-dependent manner, and exhibited the 1.58-fold greater uptake at pH 8.4 than that at pH 7.4 while there was no change in uptake between pH 6.4 and pH 7.4, suggesting that passive diffusion is not enough to explain LTR uptake. The inhibition study showed the possible influence of lysosomal trapping on cationic drug transport by retinal capillary endothelial cells since LTR uptake was significantly inhibited by cationic amphiphilic drugs. Inhibition profiling and the estimation of IC50 suggested the influence of lysosomal trapping on propranolol and low-affinity pyrilamine transport while lysosomal trapping had only a partial effect on verapamil, clonidine, nicotine and high-affinity pyrilamine transport in retinal capillary endothelial cells.

Direct Numerical Simulation of Liquid Transport Through Fibrous Porous Media

NASA Astrophysics Data System (ADS)

Palakurthi, Nikhil Kumar

Fluid flow through fibrous media occurs in many industrial processes, including, but not limited, to fuel cell technology, drug delivery patches, sanitary products, textile reinforcement, filtration, heat exchangers, and performance fabrics. Understanding the physical processes involved in fluid flow through fibrous media is essential for their characterization as well as for the optimization and development of new products. Macroscopic porous-media equations require constitutive relations, which account for the physical processes occurring at the micro-scale, to predict liquid transport at the macro-scale. In this study, micro-scale simulations were conducted using conventional computational fluid dynamics (CFD) technique (finite-volume method) to determine the macroscopic constitutive relations. The first part of this thesis deals with the single-phase flow in fibrous media, following which multi-phase flow through fibrous media was studied. Darcy permeability is an important parameter that characterizes creeping flow through a fibrous porous medium. It has a complex dependence on the medium's properties such as fibers' in-plane and through-plane orientation, diameter, aspect ratio, curvature, and porosity. A suite of 3D virtual fibrous structures with a wide range of geometric properties were constructed, and the permeability values of the structures were calculated by solving the 3D incompressible Navier-Stokes equations. The through-plane permeability was found to be a function of only the fiber diameter, the fibers' through-plane orientation, and the porosity of the medium. The numerical results were used to extend a permeability-porosity relation, developed in literature for 3D isotropic fibrous media, to a wide range of fibers' through-plane orientations. In applications where rate of capillary penetration is important, characterization of porous media usually involves determination of either the effective pore radius from capillary penetration experiments or a representative pore radius (R50) from pore-size distribution data. The relationship between effective and representative pore radii was studied by performing direct simulations of capillary penetration of a wetting liquid using a finite-volume-based volume-of-fluid (VOF) method. The simulated unidirectional liquid penetration through fibrous media followed Lucas-Washburn kinetics (L ˜ t1/2), except during the initial stages, which are dominated by inertial forces. Even though fluid properties and contact angle were kept constant in the simulations, the effective pore radii were found to be quite different from the representative radii. It can be concluded that the differences between effective and representative pore radii did not arise from contact angle variations. The unsaturated flow through fibrous media at the macro-scale is typically described using Richard's equation which requires constitutive relations: capillary pressure and permeability as a function of liquid saturation. In the present study, the quasi-static capillary pressure-saturation (P c-S) relationship for the primary drainage in a 3D isotropic fibrous medium was determined by performing micro-scale simulations using a VOF method. The Pc-S relationship obtained from the VOF method was compared with the results from the full-morphology (FM) method. Good agreement was observed between the results from the VOF and FM methods, thus suggesting that the FM method, a computationally less intensive method as compared to VOF method, may be sufficient for estimating the Pc-S relationship for primary drainage.

Heat Transfer by Thermo-capillary Convection -Sounding Rocket COMPERE Experiment SOURCE

NASA Astrophysics Data System (ADS)

Dreyer, Michael; Fuhrmann, Eckart

The sounding rocket COMPERE experiment SOURCE was successfully flown on MASER 11, launched in Kiruna (ESRANGE), May 15th, 2008. SOURCE has been intended to partly ful-fill the scientific objectives of the European Space Agency (ESA) Microgravity Applications Program (MAP) project AO-2004-111 (Convective boiling and condensation). Three parties of principle investigators have been involved to design the experiment set-up: ZARM for thermo-capillary flows, IMFT (Toulouse, France) for boiling studies, EADS Astrium (Bremen, Ger-many) for depressurization. The topic of this paper is to study the effect of wall heat flux on the contact line of the free liquid surface and to obtain a correlation for a convective heat trans-fer coefficient. The experiment has been conducted along a predefined time line. A preheating sequence at ground was the first operation to achieve a well defined temperature evolution within the test cell and its environment inside the rocket. Nearly one minute after launch, the pressurized test cell was filled with the test liquid HFE-7000 until a certain fill level was reached. Then the free surface could be observed for 120 s without distortion. Afterwards, the first depressurization was started to induce subcooled boiling, the second one to start saturated boiling. The data from the flight consists of video images and temperature measurements in the liquid, the solid, and the gaseous phase. Data analysis provides the surface shape versus time and the corresponding apparent contact angle. Computational analysis provides information for the determination of the heat transfer coefficient in a compensated gravity environment where a flow is caused by the temperature difference between the hot wall and the cold liquid. The paper will deliver correlations for the effective contact angle and the heat transfer coefficient as a function of the relevant dimensionsless parameters as well as physical explanations for the observed behavior. The data will be used for benchmarking of commercial CFD codes and the tank design (using these codes) of future cryogenic upper stages. References Eckart Fuhrmann, Michael E. Dreyer, Description of the Sounding Rocket Experiment SOURCE, Microgravity sci. technol., 20/3-4, 206 (2008)

Determination of Surface Tension of Surfactant Solutions through Capillary Rise Measurements: An Image-Processing Undergraduate Laboratory Experiment

ERIC Educational Resources Information Center

Huck-Iriart, Cristia´n; De-Candia, Ariel; Rodriguez, Javier; Rinaldi, Carlos

2016-01-01

In this work, we described an image processing procedure for the measurement of surface tension of the air-liquid interface using isothermal capillary action. The experiment, designed for an undergraduate course, is based on the analysis of a series of solutions with diverse surfactant concentrations at different ionic strengths. The objective of…

Nonlinear Dynamics of Formation of Drops of Non-Newtonian Liquids from Capillaries: Satellite Formation and Flow Transitions

NASA Astrophysics Data System (ADS)

Yildirim, Ozgur E.; Basaran, Osman A.

1999-11-01

Drop formation from capillaries, and the often undesired phenomenon of satellite generation, play a central role in diverse applications including ink-jet printing, biochip processors, and spray coating, where the working fluid is usually non-Newtonian. Although some work has been done in related areas, the phenomenon of formation of drops of non--Newtonian fluids from capillaries has remained largely unexplored. Here a theoretical approach is adopted to study the dripping of axisymmetric drops of non--Newtonian liquids from capillaries. The constitutive equation used accounts for both shear thinning and strain hardening. First, regular perturbation theory is utilized to reduce the spatial dimension of the governing equations to one. The computations rely on Galerkin/finite element analysis with adaptive finite differencing for time integration. The dynamics are followed beyond the first breakup to investigate conditions for occurrence of satellites. Effect of increasing flow rate is also studied to uncover transitions that occur as one moves from a regime of periodic drop formation to one of jetting.

Evaporation effect on two-dimensional wicking in porous media.

PubMed

Benner, Eric M; Petsev, Dimiter N

2018-03-15

We analyze the effect of evaporation on expanding capillary flow for losses normal to the plane of a two-dimensional porous medium using the potential flow theory formulation of the Lucas-Washburn method. Evaporation induces a finite steady state liquid flux on capillary flows into fan-shaped domains which is significantly greater than the flux into media of constant cross section. We introduce the evaporation-capillary number, a new dimensionless quantity, which governs the frontal motion when multiplied by the scaled time. This governing product divides the wicking behavior into simple regimes of capillary dominated flow and evaporative steady state, as well as the intermediate regime of evaporation influenced capillary driven motion. We also show flow dimensionality and evaporation reduce the propagation rate of the wet front relative to the Lucas-Washburn law. Copyright © 2017 Elsevier Inc. All rights reserved.

Graphene-doped polymer nanofibers for low-threshold nonlinear optical waveguiding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Chao; Yu, Shao-Liang; Wang, Hong -Qing

Graphene-doped polymer nanofibers are fabricated by taper drawing of solvated polyvinyl alcohol doped with liquid-phase exfoliated graphene flakes. Nanofibers drawn this way typically have diameters measured in hundreds of nanometers and lengths in tens of millimeters; they show excellent uniformity and surface smoothness for optical waveguiding. Owing to their tightly confined waveguiding behavior, light–matter interaction in these subwavelength-diameter nanofibers is significantly enhanced. Using approximately 1350-nm-wavelength femto-second pulses, we demonstrate saturable absorption behavior in these nanofibers with a saturation threshold down to 0.25 pJ pulse -1 (peak power ~1.3 W). Additionally, using 1064-nm-wavelength nanosecond pulses as switching light, we show all-opticalmore » modulation of a 1550-nm-wavelength signal light guided along a single nanofiber with a switching peak power of ~3.2 W.« less

Graphene-doped polymer nanofibers for low-threshold nonlinear optical waveguiding

DOE PAGES

Meng, Chao; Yu, Shao-Liang; Wang, Hong -Qing; ...

2015-11-06

Graphene-doped polymer nanofibers are fabricated by taper drawing of solvated polyvinyl alcohol doped with liquid-phase exfoliated graphene flakes. Nanofibers drawn this way typically have diameters measured in hundreds of nanometers and lengths in tens of millimeters; they show excellent uniformity and surface smoothness for optical waveguiding. Owing to their tightly confined waveguiding behavior, light–matter interaction in these subwavelength-diameter nanofibers is significantly enhanced. Using approximately 1350-nm-wavelength femto-second pulses, we demonstrate saturable absorption behavior in these nanofibers with a saturation threshold down to 0.25 pJ pulse -1 (peak power ~1.3 W). Additionally, using 1064-nm-wavelength nanosecond pulses as switching light, we show all-opticalmore » modulation of a 1550-nm-wavelength signal light guided along a single nanofiber with a switching peak power of ~3.2 W.« less

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.

Measuring Interfacial Tension Between Immiscible Liquids

NASA Technical Reports Server (NTRS)

Rashidnia, Nasser; Balasubramaniam, R.; Delsignore, David M.

1995-01-01

Glass capillary tube technique measures interfacial tension between two immiscible liquids. Yields useful data over fairly wide range of interfacial tensions, both for pairs of liquids having equal densities and pairs of liquids having unequal densities. Data on interfacial tensions important in diverse industrial chemical applications, including enhanced extraction of oil; printing; processing foods; and manufacture of paper, emulsions, foams, aerosols, detergents, gel encapsulants, coating materials, fertilizers, pesticides, and cosmetics.

Absorbance and fluorometric sensing with capillary wells microplates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Han Yen; Cheong, Brandon Huey-Ping; Neild, Adrian

2010-12-15

Detection and readout from small volume assays in microplates are a challenge. The capillary wells microplate approach [Ng et al., Appl. Phys. Lett. 93, 174105 (2008)] offers strong advantages in small liquid volume management. An adapted design is described and shown here to be able to detect, in a nonimaging manner, fluorescence and absorbance assays minus the error often associated with meniscus forming at the air-liquid interface. The presence of bubbles in liquid samples residing in microplate wells can cause inaccuracies. Pipetting errors, if not adequately managed, can result in misleading data and wrong interpretations of assay results; particularly inmore » the context of high throughput screening. We show that the adapted design is also able to detect for bubbles and pipetting errors during actual assay runs to ensure accuracy in screening.« less

Hydraulic droplet coarsening in open-channel capillaries

NASA Astrophysics Data System (ADS)

Warren, Patrick B.

2016-11-01

Over a range of liquid-solid contact angles, an open-channel capillary with curved or angled sides can show a maximum in the Laplace pressure as a function of the filling state. Examples include double-angle wedges, grooves scored into flat surfaces, steps on surfaces, and the groove between touching parallel cylinders. The liquid in such a channel exhibits a beading instability if the channel is filled beyond the Laplace pressure maximum. The subsequent droplet coarsening takes place by hydraulic transport through the connecting liquid columns that remain in the groove. A mean-field scaling argument predicts the characteristic droplet radius R ˜t1 /7 , as a function of time t . This is confirmed by one-dimensional simulations of the coarsening kinetics. Some remarks are also made on the spreading kinetics of an isolated drop deposited in such a channel.

Monolithic liquid crystal waveguide Fourier transform spectrometer for gas species sensing

NASA Astrophysics Data System (ADS)

Chao, Tien-Hsin; Lu, Thomas T.; Davis, Scott R.; Rommel, Scott D.; Farca, George; Luey, Ben; Martin, Alan; Anderson, Michael H.

2011-04-01

Jet Propulsion Lab and Vescent Photonics Inc. and are jointly developing an innovative ultracompact (volume < 10 cm3), ultra-low power (<10-3 Watt-hours per measurement and zero power consumption when not measuring), completely non-mechanical Liquid Crystal Waveguide Fourier Transform Spectrometer (LCWFTS) that will be suitable for a variety of remote-platform, in-situ measurements. These devices are made possible by novel electro-evanescent waveguide architecture, enabling "monolithic chip-scale" Electro Optic-FTS (EO-FTS) sensors. The potential performance of these EO-FTS sensors include: i) a spectral range throughout 0.4-5 μm (25000 - 2000 cm-1), ii) high-resolution (Δλ <= 0.1 nm), iii) high-speed (< 1 ms) measurements, and iv) rugged integrated optical construction. This performance potential enables the detection and quantification of a large number of different atmospheric gases simultaneously in the same air mass and the rugged construction will enable deployment on previously inaccessible platforms. The sensor construction is also amenable for analyzing aqueous samples on remote floating or submerged platforms. We will report a proof-of-principle prototype LCWFTS sensor that has been demonstrated in the near-IR (range of 1450-1700 nm) with a 5 nm resolution. This performance is in good agreement with theoretical models, which are being used to design and build the next generation LCWFTS devices.

Shear strength of wet granular materials: Macroscopic cohesion and effective stress : Discrete numerical simulations, confronted to experimental measurements.

PubMed

Badetti, Michel; Fall, Abdoulaye; Chevoir, François; Roux, Jean-Noël

2018-05-28

Rheometric measurements on assemblies of wet polystyrene beads, in steady uniform quasistatic shear flow, for varying liquid content within the small saturation (pendular) range of isolated liquid bridges, are supplemented with a systematic study by discrete numerical simulations. The numerical results agree quantitatively with the experimental ones provided that the intergranular friction coefficient is set to the value [Formula: see text], identified from the behaviour of the dry material. Shear resistance and solid fraction [Formula: see text] are recorded as functions of the reduced pressure [Formula: see text], which, defined as [Formula: see text], compares stress [Formula: see text], applied in the velocity gradient direction, to the tensile strength [Formula: see text] of the capillary bridges between grains of diameter a, and characterizes cohesion effects. The simplest Mohr-Coulomb relation with [Formula: see text]-independent cohesion c applies as a good approximation for large enough [Formula: see text] (typically [Formula: see text]. Numerical simulations extend to different values of μ and, compared to experiments, to a wider range of [Formula: see text]. The assumption that capillary stresses act similarly to externally applied ones onto the dry granular contact network (effective stresses) leads to very good (although not exact) predictions of the shear strength, throughout the numerically investigated range [Formula: see text] and [Formula: see text]. Thus, the internal friction coefficient [Formula: see text] of the dry material still relates the contact force contribution to stresses, [Formula: see text], while the capillary force contribution to stresses, [Formula: see text], defines a generalized Mohr-Coulomb cohesion c, depending on [Formula: see text] in general. c relates to [Formula: see text] , coordination numbers and capillary force network anisotropy. c increases with liquid content through the pendular regime interval, to a larger extent, the smaller the friction coefficient. The simple approximation ignoring capillary shear stress [Formula: see text] (referred to as the Rumpf formula) leads to correct approximations for the larger saturation range within the pendular regime, but fails to capture the decrease of cohesion for smaller liquid contents.

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.

Synthetic Capillaries to Control Microscopic Blood Flow.

PubMed

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

2016-02-24

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.

Geometric control of capillary architecture via cell-matrix mechanical interactions.

PubMed

Sun, Jian; Jamilpour, Nima; Wang, Fei-Yue; Wong, Pak Kin

2014-03-01

Capillary morphogenesis is a multistage, multicellular activity that plays a pivotal role in various developmental and pathological situations. In-depth understanding of the regulatory mechanism along with the capability of controlling the morphogenic process will have direct implications on tissue engineering and therapeutic angiogenesis. Extensive research has been devoted to elucidate the biochemical factors that regulate capillary morphogenesis. The roles of geometric confinement and cell-matrix mechanical interactions on the capillary architecture, nevertheless, remain largely unknown. Here, we show geometric control of endothelial network topology by creating physical confinements with microfabricated fences and wells. Decreasing the thickness of the matrix also results in comparable modulation of the network architecture, supporting the boundary effect is mediated mechanically. The regulatory role of cell-matrix mechanical interaction on the network topology is further supported by alternating the matrix stiffness by a cell-inert PEG-dextran hydrogel. Furthermore, reducing the cell traction force with a Rho-associated protein kinase inhibitor diminishes the boundary effect. Computational biomechanical analysis delineates the relationship between geometric confinement and cell-matrix mechanical interaction. Collectively, these results reveal a mechanoregulation scheme of endothelial cells to regulate the capillary network architecture via cell-matrix mechanical interactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Instrument platforms for nano liquid chromatography.

PubMed

Šesták, Jozef; Moravcová, Dana; Kahle, Vladislav

2015-11-20

The history of liquid chromatography started more than a century ago and miniaturization and automation are two leading trends in this field. Nanocolumn liquid chromatography (nano LC) and largely synonymous capillary liquid chromatography (capillary LC) are the most recent results of this process where miniaturization of column dimensions and sorbent particle size play crucial role. Very interesting results achieved in the research of extremely miniaturized LC columns at the end of the last century lacked distinctive raison d'être and only advances in mass spectrometry brought a real breakthrough. Configuration of nano LC-electrospray ionization mass spectrometry (LC-ESI-MS) has become a basic tool in bioanalytical chemistry, especially in proteomics. This review discusses and summarizes past and current trends in the realization of nano liquid chromatography (nano LC) platforms. Special attention is given to the mobile phase delivery under nanoflow rates (isocratic, gradient) and sample injection to the nanocolumn. Available detection techniques applied in nano LC separations are also briefly discussed. We followed up the key themes from the original scientific reports over gradual improvements up to the contemporary commercial solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

LABORATORY INVESTIGATION OF RESIDUAL LIQUID ORGANICS FROM SPILLS, LEAKS, AND THE DISPOSAL OF HAZARDOUS WASTES IN GROUNDWATER

EPA Science Inventory

Organic liquids that are essentially immiscible with water migrate through the subsurface through the influence of capillary, viscous and buoyancy forces. our experimental methods were employed. irst, quantitative displacement experiments using short soil columns; second, additio...

LABORATORY INVESTIGATION OF RESIDUAL LIQUID ORGANICS FROM SPILLS, LEAKS, AND THE DISPOSAL OF HAZARDOUS WASTES IN GROUNDWATER

EPA Science Inventory

Organic liquids that are essentially immiscible with water migrate through the subsurface through the influence of capillary, viscous and buoyancy forces. Four experimental methods were employed. First, quantitative displacement experiments using short soil columns; second, add...

Wetting, meniscus structure, and capillary interactions of microspheres bound to a cylindrical liquid interface.

PubMed

Kim, Paul Y; Dinsmore, Anthony D; Hoagland, David A; Russell, Thomas P

2018-03-14

Wetting, meniscus structure, and capillary interactions for polystyrene microspheres deposited on constant curvature cylindrical liquid interfaces, constructed from nonvolatile ionic or oligomeric liquids, were studied by optical interferometry and optical microscopy. The liquid interface curvature resulted from the preferential wetting of finite width lines patterned onto planar silicon substrates. Key variables included sphere diameter, nominal (or average) contact angle, and deviatoric interfacial curvature. Menisci adopted the quadrupolar symmetry anticipated by theory, with interfacial deformation closely following predicted dependences on sphere diameter and nominal contact angle. Unexpectedly, the contact angle was not constant locally around the contact line, the nominal contact angle varied among seemingly identical spheres, and the maximum interface deviation did not follow the predicted dependence on deviatoric interfacial curvature. Instead, this deviation was up to an order-of-magnitude larger than predicted. Trajectories of neighboring microspheres visually manifested quadrupole-quadrupole interactions, eventually producing square sphere packings that foreshadow interfacial assembly as a potential route to hierarchical 2D particle structures.

Evaporation-driven clustering of microscale pillars and lamellae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Tae-Hong; Kim, Jungchul; Kim, Ho-Young, E-mail: hyk@snu.ac.kr

As a liquid film covering an array of micro- or nanoscale pillars or lamellae evaporates, its meniscus pulls the elastic patterns together because of capillary effects, leading to clustering of the slender microstructures. While this elastocapillary coalescence may imply various useful applications, it is detrimental to a semiconductor manufacturing process called the spin drying, where a liquid film rinses patterned wafers until drying. To understand the transient mechanism underlying such self-organization during and after liquid evaporation, we visualize the clustering dynamics of polymer micropatterns. Our visualization experiments reveal that the patterns clumped during liquid evaporation can be re-separated when completelymore » dried in some cases. This restoration behavior is explained by considering adhesion energy of the patterns as well as capillary forces, which leads to a regime map to predict whether permanent stiction would occur. This work does not only extend our understanding of micropattern stiction, but also suggests a novel path to control and prevent pattern clustering.« less

[Structure of newly formed capillaries of the rabbit cornea (electron microscopic study)].

PubMed

Gurina, O Iu; Karaganov, Ia L

1984-08-01

Owing to a complex application of topical analysis and tracer technique, it is possible to carry out a light optic and electron microscopic investigation of newly formed capillaries growing in the rabbit cornea after its chemical burn. The ultrastructural analysis demonstrates certain polymorphism of morphological organization of endotheliocyte in the newly formed capillaries. There is a rather elevated amount of free ribosomes, mitochondria, microtubules and microfilaments in cytoplasm. The granular endoplasmic reticulum and Golgi complex are hypertrophied. Weibel--Palade bodies appear. Taking into account certain morpho-functional peculiarities of endothelial cells along the course of the growing capillaries, on the 8th day of growth three zone are distinguished: 1--area of nondifferentiated endothelium (apex of the capillary), 2--transitional zone, 3--zone of relatively differentiated endothelium situating in the place where the capillary gets off the parental vessel. According to the zones distinguished, the ways of trans-endothelial transport of molecules are investigated. In formation of the capillary barrier-transport function an important role belongs to polymorphism of the endothelial cells along the course of the growing capillary which is determined by differentiation degree of these cells depending on their participation in permeability.

Subtle exchange model of flow depended on the blood cell shape to enhance the micro-circulation in capillary

NASA Astrophysics Data System (ADS)

Chan, Iatneng

2012-02-01

In general the exchange of gases or other material in capillary system is conceptualized by the diffusion effect. But in this model, we investigate a micro-flow pattern by simulation and computation on a micro-exchange model in which the blood cell is a considered factor, especially on its shape. It shows that the cell benefits the circulation while it is moving in the capillary. In the study, the flow detail near the cell surface is mathematically analyzed, such that the Navier-Stokes equations are applied and the viscous factor is also briefly considered. For having a driven force to the motion of micro-circulation, a breathing mode is suggested to approximately compute on the flow rate in the blood capillary during the transfer of cell. The rate is also used to estimate the enhancement to the circulation in additional to the outcome of diffusion. Moreover in the research, the shape change of capillary wall under pressure influence is another element in the beginning calculation for the effect in the assistance to cell motion.

Acoustofluidic waveguides for localized control of acoustic wavefront in microfluidics

PubMed Central

Bian, Yusheng; Guo, Feng; Yang, Shujie; Mao, Zhangming; Bachman, Hunter; Tang, Shi-Yang; Ren, Liqiang; Zhang, Bin; Gong, Jianying; Guo, Xiasheng

2017-01-01

The precise manipulation of acoustic fields in microfluidics is of critical importance for the realization of many biomedical applications. Despite the tremendous efforts devoted to the field of acoustofluidics during recent years, dexterous control, with an arbitrary and complex acoustic wavefront, in a prescribed, microscale region is still out of reach. Here, we introduce the concept of acoustofluidic waveguide, a three-dimensional compact configuration that is capable of locally guiding acoustic waves into a fluidic environment. Through comprehensive numerical simulations, we revealed the possibility of forming complex field patterns with defined pressure nodes within a highly localized, pre-determined region inside the microfluidic chamber. We also demonstrated the tunability of the acoustic field profile through controlling the size and shape of the waveguide geometry, as well as the operational frequency of the acoustic wave. The feasibility of the waveguide concept was experimentally verified via microparticle trapping and patterning. Our acoustofluidic waveguiding structures can be readily integrated with other microfluidic configurations and can be further designed into more complex types of passive acoustofluidic devices. The waveguide platform provides a promising alternative to current acoustic manipulation techniques and is useful in many applications such as single-cell analysis, point-of-care diagnostics, and studies of cell–cell interactions. PMID:29358901

On-line capillary electrophoresis/laser-induced fluorescence/mass spectrometry analysis of glycans labeled with Teal™ fluorescent dye using an electrokinetic sheath liquid pump-based nanospray ion source.

PubMed

Khan, Shaheer; Liu, Jenkuei; Szabo, Zoltan; Kunnummal, Baburaj; Han, Xiaorui; Ouyang, Yilan; Linhardt, Robert J; Xia, Qiangwei

2018-06-15

N-linked glycan analysis of recombinant therapeutic proteins, such as monoclonal antibodies, Fc-fusion proteins, and antibody-drug conjugates, provides valuable information regarding protein therapeutics glycosylation profile. Both qualitative identification and quantitative analysis of N-linked glycans on recombinant therapeutic proteins are critical analytical tasks in the biopharma industry during the development of a biotherapeutic. Currently, such analyses are mainly carried out using capillary electrophoresis/laser-induced fluorescence (CE/LIF), liquid chromatography/fluorescence (LC/FLR), and liquid chromatography/fluorescence/mass spectrometry (LC/FLR/MS) technologies. N-linked glycans are first released from glycoproteins by enzymatic digestion, then labeled with fluorescence dyes for subsequent CE or LC separation, and LIF or MS detection. Here we present an on-line CE/LIF/MS N-glycan analysis workflow that incorporates the fluorescent Teal™ dye and an electrokinetic pump-based nanospray sheath liquid capillary electrophoresis/mass spectrometry (CE/MS) ion source. Electrophoresis running buffer systems using ammonium acetate and ammonium hydroxide were developed for the negative ion mode CE/MS analysis of fluorescence-labeled N-linked glycans. Results show that on-line CE/LIF/MS analysis can be readily achieved using this versatile CE/MS ion source on common CE/MS instrument platforms. This on-line CE/LIF/MS method using Teal™ fluorescent dye and electrokinetic pump-based nanospray sheath liquid CE/MS coupling technology holds promise for on-line quantitation and identification of N-linked glycans on recombinant therapeutic proteins. Copyright © 2018 John Wiley & Sons, Ltd.

Multiphysics Modelling of Sodium Sulfur Battery

NASA Astrophysics Data System (ADS)

Mason, Jerry Hunter

Due to global climate change and the desire to decrease greenhouse gas emissions, large scale energy storage has become a critical issue. Renewable energy sources such as wind and solar will not be a viable energy source unless the storage problem is solved. One of the practical and cost effective solutions for this problem is sodium sulfur batteries. These batteries are comprised of liquid electrode materials suspended in porous media and operate at relatively high temperatures (>300°C). The sodium anode and the sulfur/sodium-polysulfide cathode are separated by a solid electrolyte made of beta-alumina or NASICON material. Due to the use of porous materials in the electrodes, capillary pressure and the combination of capillary action and gravity become important. Capillary pressure has a strong dependence on the wetting phase (liquid electrode material) saturation; therefore sharp concentration gradients can occur between the inert gas and the electrode liquid, especially within the cathode. These concentration gradients can have direct impacts on the electrodynamics of the battery as they may produce areas of high electrical potential variation, which can decrease efficiency and even cause failures. Then, thermal management also becomes vital since the electrochemistry and material properties are sensitive to temperature gradients. To investigate these phenomena in detail and to attempt to improve upon battery design a multi-dimensional, multi-phase code has been developed and validated in this study. Then a porous media flow model is implemented. Transport equations for charge, mass and heat are solved in a time marching fashion using finite volume method. Material properties are calculated and updated as a function of time. The porous media model is coupled with the continuity equation and a separate diffusion equation for the liquid sodium in the melt. The total mass transport model is coupled with charge transport via Faraday's law. Results show that overpotential is significantly higher in the porous region of the cathode as was predicted by models in the literature. Overpotential is also high on the electrolyte surface and wall. Alternative electrode configurations with high resistive layers recommended by previous researchers also produce areas of high potential gradient. New electrode designs including conductivity gradients and porous media property variations are simulated and compared to previous designs and then recommendations are made for optimum cell operating conditions.

Large core plastic planar optical splitter fabricated by 3D printing technology

NASA Astrophysics Data System (ADS)

Prajzler, Václav; Kulha, Pavel; Knietel, Marian; Enser, Herbert

2017-10-01

We report on the design, fabrication and optical properties of large core multimode optical polymer splitter fabricated using fill up core polymer in substrate that was made by 3D printing technology. The splitter was designed by the beam propagation method intended for assembling large core waveguide fibers with 735 μm diameter. Waveguide core layers were made of optically clear liquid adhesive, and Veroclear polymer was used as substrate and cover layers. Measurement of optical losses proved that the insertion optical loss was lower than 6.8 dB in the visible spectrum.

High-Tc superconductor coplanar waveguide filter

NASA Technical Reports Server (NTRS)

Chew, Wilbert; Bajuk, Louis J.; Cooley, Thomas W.; Foote, Marc C.; Hunt, Brian D.; Rascoe, Daniel L.; Riley, A. L.

1991-01-01

Coplanar waveguide (CPW) low-pass filters made of YBa2Cu3O(7-delta) (YBCO) on LaAlO3 substrates, with dimensions suited for integrated circuits, were fabricated and packaged. A complete filter gives a true idea of the advantages and difficulties in replacing thin-film metal with a high-temperature superconductor in a practical circuit. Measured insertion losses in liquid nitrogen were superior to the loss of a similar thin-film copper filter throughout the 0- to 9.5-GHz passband. These results demonstrate the performance of fully patterned YBCO in a practical CPW structure after sealing in a hermetic package.

Advanced proteomic liquid chromatography

PubMed Central

Xie, Fang; Smith, Richard D.; Shen, Yufeng

2012-01-01

Liquid chromatography coupled with mass spectrometry is the predominant platform used to analyze proteomics samples consisting of large numbers of proteins and their proteolytic products (e.g., truncated polypeptides) and spanning a wide range of relative concentrations. This review provides an overview of advanced capillary liquid chromatography techniques and methodologies that greatly improve separation resolving power and proteomics analysis coverage, sensitivity, and throughput. PMID:22840822

Nucleation theory - Is replacement free energy needed?. [error analysis of capillary approximation

NASA Technical Reports Server (NTRS)

Doremus, R. H.

1982-01-01

It has been suggested that the classical theory of nucleation of liquid from its vapor as developed by Volmer and Weber (1926) needs modification with a factor referred to as the replacement free energy and that the capillary approximation underlying the classical theory is in error. Here, the classical nucleation equation is derived from fluctuation theory, Gibb's result for the reversible work to form a critical nucleus, and the rate of collision of gas molecules with a surface. The capillary approximation is not used in the derivation. The chemical potential of small drops is then considered, and it is shown that the capillary approximation can be derived from thermodynamic equations. The results show that no corrections to Volmer's equation are needed.

[Lombosacral epidural capillary hemangioma mimicking a dumbbell-shaped neurinoma: A case report and review of the literature].

PubMed

Egu, K; Kinata-Bambino, S; Mounadi, M; Rachid El Maaqili, M; El Abbadi, N

2016-04-01

Capillary hemangiomas are benign endothelial cell neoplasms that are believed to be hamartomatous proliferations of vascular endothelial cells. The occurrence of spinal epidural capillary hemangiomas is exceedingly rare. Only 8 epidurally located cases of capillary hemangiomas in the spinal canal have been reported in the literature. We report for the first time, to our knowledge, a case of lumbosacral epidural capillary hemangioma revealed by S1 back pain and radicular pain in a 60-year-old patient, caused by an L5-S1 epidural capillary hemangioma. The neurological symptoms of the patient improved after surgery. Spinal epidural capillary hemangioma is exceedingly rare. These lesions are benign and can mimic dumbbell-shaped neurinoma. Total removal by surgery is curative. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

A Review of String Vessels or Collapsed, Empty Basement Membrane Tubes

PubMed Central

Brown, William R.

2011-01-01

String vessels are thin connective tissue strands, remnants of capillaries, with no endothelial cells; they do not carry blood flow. They occur in numerous species, particularly in the central nervous system, but can occur in any tissue where capillaries have died. String vessels are often associated with pathologies such as Alzheimer’s disease, ischemia, and irradiation, but are also found in normal human brains from preterm babies to the aged. They provide a record of the original blood vessel location, but gradually disappear after months or years. There have been numerous studies of string vessels (acellular capillaries) in the retina, because retinal vessels can be seen in great detail in whole mounts after trypsin digestion. Capillary regression occurs by apoptosis, synchronously along capillary segments, with macrophages engulfing apoptotic endothelial cells. Macrophages may cause the apoptosis, or the regression may be triggered by loss of the endothelial cell survival factor VEGF. VEGF expression is induced by hypoxia and promotes capillary growth. Cessation of blood flow eliminates the shear stress that helps maintain endothelial cell survival. Capillaries can re-grow by proliferation and migration of endothelial cells into empty basement membrane tubes, which provide a structural scaffold, replete with signaling molecules. This is a problem in tumor control, but useful for recovery from capillary loss. There is an age-related waning of VEGF expression in response to hypoxia. This causes an age-related decline in cerebral angiogenesis and results in neuronal loss. It may also contribute to the proposed age-related loss of brain reserve. PMID:20634580

Capillary photoelectrode structures for photoelectrochemical and photocatalytic cells

DOEpatents

Wang, Xudong; Li, Zhaodong; Cai, Zhiyong; Yao, Chunhua

2017-05-02

Photocatalytic structures having a capillary-force based electrolyte delivery system are provided. Also provided are photoelectrochemical and photocatalytic cells incorporating the structures and methods for using the cells to generate hydrogen and/or oxygen from water. The photocatalytic structures use an electrolyte-transporting strip comprising a porous network of cellulose nanofibers to transport electrolyte from a body of the electrolyte to a porous photoelectrode or a porous photocatalytic substrate via capillary force.

Numerical Simulation of Sickle Cell Blood Flow in the Microcirculation

NASA Astrophysics Data System (ADS)

Berger, Stanley A.; Carlson, Brian E.

2001-11-01

A numerical simulation of normal and sickle cell blood flow through the transverse arteriole-capillary microcirculation is carried out to model the dominant mechanisms involved in the onset of vascular stasis in sickle cell disease. The transverse arteriole-capillary network is described by Strahler's network branching method, and the oxygen and blood transport in the capillaries is modeled by a Krogh cylinder analysis utilizing Lighthill's lubrication theory, as developed by Berger and King. Poiseuille's law is used to represent blood flow in the arterioles. Applying this flow and transport model and utilizing volumetric flow continuity at each network bifurcation, a nonlinear system of equations is obtained, which is solved iteratively using a steepest descent algorithm coupled with a Newton solver. Ten different networks are generated and flow results are calculated for normal blood and sickle cell blood without and with precapillary oxygen loss. We find that total volumetric blood flow through the network is greater in the two sickle cell blood simulations than for normal blood owing to the anemia associated with sickle cell disease. The percentage of capillary blockage in the network increases dramatically with decreasing pressure drop across the network in the sickle cell cases while there is no blockage when normal blood flows through simulated networks. It is concluded that, in sickle cell disease, without any vasomotor dilation response to decreasing oxygen concentrations in the blood, capillary blockage will occur in the microvasculature even at average pressure drops across the transverse arteriole-capillary networks.

Viscosity of particulate soap films: approaching the jamming of 2D capillary suspensions.

PubMed

Timounay, Yousra; Rouyer, Florence

2017-05-14

We compute the effective viscosity of particulate soap films thanks to local velocity fields obtained by Particle Image Velocimetry (PIV) during film retraction experiments. We identify the jamming of these 2D capillary suspensions at a critical particle surface fraction (≃0.84) where effective viscosity diverges. Pair correlation function and number of neighbors in contact or close to contact reveal the cohesive nature of this 2D capillary granular media. The experimental 2D dynamic viscosities can be predicted by a model considering viscous dissipation at the liquid interfaces induced by the motion of individual particles.

Elastocapillarity: When Surface Tension Deforms Elastic Solids

NASA Astrophysics Data System (ADS)

Bico, José; Reyssat, Étienne; Roman, Benoît

2018-01-01

Although negligible at large scales, capillary forces may become dominant for submillimetric objects. Surface tension is usually associated with the spherical shape of small droplets and bubbles, wetting phenomena, imbibition, or the motion of insects at the surface of water. However, beyond liquid interfaces, capillary forces can also deform solid bodies in their bulk, as observed in recent experiments with very soft gels. Capillary interactions, which are responsible for the cohesion of sandcastles, can also bend slender structures and induce the bundling of arrays of fibers. Thin sheets can spontaneously wrap liquid droplets within the limit of the constraints dictated by differential geometry. This review aims to describe the different scaling parameters and characteristic lengths involved in elastocapillarity. We focus on three main configurations, each characterized by a specific dimension: three-dimensional (3D), deformations induced in bulk solids; 1D, bending and bundling of rod-like structures; and 2D, bending and stretching of thin sheets. Although each configuration deserves a detailed review, we hope our broad description provides a general view of elastocapillarity.

Electrically modulated capillary filling imbibition of nematic liquid crystals

NASA Astrophysics Data System (ADS)

Dhar, Jayabrata; Chakraborty, Suman

2018-04-01

The flow of nematic liquid crystals (NLCs) in the presence of an electric field is typically characterized by the variation in its rheological properties due to transition in its molecular arrangements. Here, we bring out a nontrivial interplay of a consequent alteration in the resistive viscous effects and driving electrocapillary interactions, toward maneuvering the capillary filling dynamics over miniaturized scales. Considering a dynamic interplay of the relevant bulk and interfacial forces acting in tandem, our results converge nicely to previously reported experimental data. Finally, we attempt a scaling analysis to bring forth further insight to the reported observations. Our analysis paves the way for the development of microfluidic strategies with previously unexplored paradigms of interaction between electrical and fluidic phenomenon, providing with an augmented controllability on capillary filling as compared to tthose reported to be achievable by the existing strategies. This, in turn, holds utilitarian scopes in improved designs of functional capillarities in electro-optical systems, electrorheological utilities, electrokinetic flow control, as well as in interfacing and imaging systems for biomedical microdevices.

Tube radial distribution phenomenon with a two-phase separation solution of a fluorocarbon and hydrocarbon organic solvent mixture in a capillary tube and metal compounds separation.

PubMed

Kitaguchi, Koichi; Hanamura, Naoya; Murata, Masaharu; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko

2014-01-01

A fluorocarbon and hydrocarbon organic solvent mixture is known as a temperature-induced phase-separation solution. When a mixed solution of tetradecafluorohexane as a fluorocarbon organic solvent and hexane as a hydrocarbon organic solvent (e.g., 71:29 volume ratio) was delivered in a capillary tube that was controlled at 10°C, the tube radial distribution phenomenon (TRDP) of the solvents was clearly observed through fluorescence images of the dye, perylene, dissolved in the mixed solution. The homogeneous mixed solution (single phase) changed to a heterogeneous solution (two phases) with inner tetradecafluorohexane and outer hexane phases in the tube under laminar flow conditions, generating the dynamic liquid-liquid interface. We also tried to apply TRDP to a separation technique for metal compounds. A model analyte mixture, copper(II) and hematin, was separated through the capillary tube, and detected with a chemiluminescence detector in this order within 4 min.