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Sample records for capillary barrier field

  1. Numerical simulations of capillary barrier field tests

    Energy Technology Data Exchange (ETDEWEB)

    Morris, C.E. [Univ. of Wollongong (Australia); Stormont, J.C. [Univ. of New Mexico, Albuquerque, NM (United States)

    1997-12-31

    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior.

  2. Numerical simulations of capillary barrier field tests

    International Nuclear Information System (INIS)

    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior

  3. On the performance of capillary barriers as landfill cover

    Science.gov (United States)

    Kämpf, M.; Montenegro, H.

    Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

  4. On the performance of capillary barriers as landfill cover

    Directory of Open Access Journals (Sweden)

    M. Kämpf

    1997-01-01

    Full Text Available Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m. In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

  5. Visualization experiment to investigate capillary barrier performance in the context of a Yucca Mountain emplacement drift.

    Science.gov (United States)

    Tidwell, Vincent C; Glass, Robert J; Chocas, Connie; Barker, Glenn; Orear, Lee

    2003-01-01

    The use of capillary barriers as engineered backfill systems to divert water away from radioactive waste potentially stored in a Yucca Mountain emplacement drift is investigated. We designed and conducted a flow visualization experiment to investigate capillary barrier performance in this context. A two-dimensional, thin slab, test system replicated the physical emplacement drift to one-quarter scale (1.4-m diameter) and included the simulated drift wall, waste canister, pedestal, capillary barrier backfill, and host-rock fracture system. Water was supplied at the top of the simulated drift and allowed to discharge by way of wicks located along the left wall of the cell (simulated fractures) or by a gravity drain at the bottom of the right side (simulated impermeable rock with floor drain). Photographs captured the migration of water and a blue dye tracer within the system, analytical balances measured the mass balance of water, while tensiometers measured the capillary pressure at numerous locations. Of particular concern to this test was the drainage of the capillary barrier, which terminates against the drift wall. We found that while the simulated fractures (left side) and drain (right side) each influenced the performance of the capillary barrier at early time, they had little differential affect at later times. Also of concern was the small disparity in capillary properties between the fine and coarse layer (limited by the need of a fine-grained material that would not filter into the coarse layer under dry conditions). While the capillary barrier was able to divert the majority of flow toward the edges of the system and away from the simulated waste canister, the barrier did not preclude flow in the coarse layer, which was noted to be visually wet next to the waste canister on day 92 and was continuing to take on water at termination on day 112.

  6. Evaluating the long-term hydrology of an evapotranspiration-capillary barrier with a 1000 year design life

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.

    2016-06-25

    A surface barrier (or cover) is a commonly used technology for subsurface remediation. A key function of the barrier is to reduce or eliminate the movement of meteoric precipitation into the underlying waste zone, where it could mobilize and transport contaminants. Surface barriers are expected to perform for centuries to millennia, yet there are very few examples of performance for periods longer than a decade. The Prototype Hanford Barrier was constructed in 1994 over an existing waste site to demonstrate its long-term performance for a design period of 1000 years. This barrier is a field-scale evapotranspiration-capillary (ETC) barrier. In this design, the storage layer consists of 2-m-thick silt loam. The 19-year monitoring results show that the store-and-release mechanism for the ETC barrier worked efficiently as the storage layer was recharged in the winter season (November to March) and the stored water was released to the atmosphere in the summer season (April to October) via soil evaporation and plant transpiration. The capillary break functioned normally in improving the storage capacity and minimizing drainage. The maximum drainage observed through the ET barrier at any of the monitoring stations was only 0.178 mm yr-1 (under an enhanced precipitation condition), which is less than the design criterion. A very small amount (2.0 mm yr-1 on average) of runoff was observed during the 19-year monitoring period. The observed storage capacity of the storage layer was considerably (39%) larger than the estimated value based on the method of equilibrium of water pressure. After a controlled fire in 2008, the newly grown vegetation (primarily shallow-rooted grasses) could still release the stored water and summer precipitation to the atmosphere via transpiration. The findings are useful for predicting water storage and ET under different precipitation conditions and for the design of future barriers.

  7. Sieve plugs in fenestrae of glomerular capillaries--site of the filtration barrier?

    DEFF Research Database (Denmark)

    Rostgaard, Jørgen; Qvortrup, Klaus

    2002-01-01

    The exact location of the filtration barrier of the glomerular capillary wall, which consists of an endothelium, a basement membrane and a visceral epithelium, has not yet been determined. Apparent discrepancies between different investigators in the past could be explained if postmortem artifact......The exact location of the filtration barrier of the glomerular capillary wall, which consists of an endothelium, a basement membrane and a visceral epithelium, has not yet been determined. Apparent discrepancies between different investigators in the past could be explained if postmortem...... and a filamentous surface coat about 60 nm thick covered the interfenestral domains of the endothelial cell. Based on these purely morphological data, we dare to suggest that the fenestral plugs are the primary site of the glomerular filtration barrier - albeit highly speculative, nevertheless a logical location...

  8. The Role of Capillary Barrier in Reducing Moisture Content on Waste Packages

    International Nuclear Information System (INIS)

    Assessment of the performance of engineered capillary barriers at the potential Yucca Mountain nuclear waste repository site, in which 1.67-m-diameter waste packages are to be emplaced in 5-m-diameter tunnels according to current design, brings up aspects not commonly considered in more typical applications of capillary barriers (e.g., near-surface landfills). Engineered capillary barriers typically consist of two layers of granular materials with a sloping interface, in which the contrast in capillarity between the layers keeps infiltrating water in the upper layer. One issue is the effect of thermohydrologic processes that would occur at elevated repository temperatures (and temperature gradients). For example, backfill materials may be altered from that of the as-placed material by the hydrothermal regime imposed by the emplacement of waste in the repository, changing hydrologic properties in a way that degrades the performance of the barrier. A reduction of permeability in the upper layer might diminish the capacity of the upper layer to divert incoming seepage or to cause a ''vapor lid'' whereby buoyant vapor flow would be trapped, then condense and drain onto waste packages. Other concerns are the result of highly spatially and temporally variable seepage distribution and the very limited spatial scale available for flow attenuation and diversion

  9. Evaluating the long-term hydrology of an evapotranspiration-capillary barrier with a 1000 year design life

    Science.gov (United States)

    Zhang, Z. Fred

    2016-06-01

    A surface barrier is a commonly used technology for isolation of subsurface contaminants. Surface barriers for isolating radioactive waste are expected to perform for centuries to millennia, yet there are very few data for field-scale surface barriers for periods approaching a decade or longer. The Prototype Hanford Barrier (PHB) with a design life of 1000 years was constructed over an existing radioactive waste site in 1994 to demonstrate its long-term performance. The primary element of the PHB is an evapotranspiration-capillary (ETC) barrier in which precipitation water is stored in a fine-textured soil layer and later released to the atmosphere via evapotranspiration. To address the barrier performance under extreme conditions, this study included an enhanced precipitation stress test from 1995 to 1997 to determine barrier response to extreme precipitation events. During this period a 1000 year 24 h return rainstorm was simulated in March every year. The loss of vegetation on barrier hydrology was tested with a controlled fire test in 2008. The 19 year monitoring record shows that the store-and-release mechanism worked as well as or better than the design criterion. Average drainage from the ETC barrier amounted to an average of 0.005 mm yr-1, which is well below the design criterion of 0.5 mm yr-1. After a simulated wildfire, the naturally reestablished vegetation and increased evaporation combined to release the stored water and summer precipitation to the atmosphere such that drainage did not occur in the 5 years subsequent to the fire.

  10. Integrity of the alveolar-capillary barrier and alveolar surfactant system in smokers.

    OpenAIRE

    Schmekel, B; Bos, J.A.; A. R. Khan; Wohlfart, B; Lachmann, B.; Wollmer, P.

    1992-01-01

    BACKGROUND: The permeability of the alveolar-capillary barrier to technetium-99m labelled diethylenetriamine pentaacetate (99mTc DTPA) is known to be greatly increased in smokers, but the underlying mechanism is poorly understood. Abnormal permeability of the alveolar epithelium as well as impaired surfactant function has been suggested. The purpose of this study was to examine transudation of urea and albumin into the alveoli and alveolar surfactant function in smokers and non-smokers and to...

  11. Critical energy barrier for capillary condensation in mesopores: Hysteresis and reversibility

    Science.gov (United States)

    Hiratsuka, Tatsumasa; Tanaka, Hideki; Miyahara, Minoru T.

    2016-04-01

    Capillary condensation in the regime of developing hysteresis occurs at a vapor pressure, Pcond, 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 Pcond 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 subcritical temperatures. A careful comparison between the simulation and experiment reveals that the energy barrier for the capillary condensation has a critical dimensionless value, Wc* = 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 Wc* controls the capillary condensation pressure Pcond and also determines a boundary between the reversible condensation/evaporation regime and the developing hysteresis regime.

  12. CPMG relaxation rate dispersion in dipole fields around capillaries.

    Science.gov (United States)

    Kurz, F T; Kampf, T; Buschle, L R; Heiland, S; Schlemmer, H-P; Bendszus, M; Ziener, C H

    2016-09-01

    Transverse relaxation rates for Carr-Purcell-Meiboom-Gill (CPMG) sequences increase with inter-echo time in presence of microscopic magnetic field inhomogeneities due to nuclear spin diffusion. For a weak field approximation that includes diffusion effects, the CPMG relaxation rate shift for proton diffusion around capillaries in muscle tissue can be expressed in terms of a frequency correlation function and the inter-echo time. The present work provides an analytical expression for the local relaxation rate shift that is dependent on local blood volume fraction, diffusion coefficient, capillary radius, susceptibility difference and inter-echo time. Asymptotic regions of the model are in agreement with previous modeling results of Brooks et al., Luz et al. and Ziener et al. In comparison with simulation data, the model shows an equal or better accuracy than established approximations. Also, model behavior coincides with experimental data for rat heart and skeletal muscle. The present work provides analytical tools to extract sub-voxel information about uniform capillary networks that can be used to study capillary organization or micro-circulatory remodeling. PMID:27071310

  13. Fabrication of Barrier Ribs for PDP by Capillary Infiltration Process and Their Sintering Behavior

    Institute of Scientific and Technical Information of China (English)

    Tae Jung Tang; Hak Nynu Choi; Chan Hyoung Kang; Yong Seog Kim

    2004-01-01

    Closed-cell type barrier ribs such as meander, honeycomb, SDR, and waffle types were produced using capillary molding process. Sintering of the ribs revealed that the ribs with asymmetric geometry such as meander and SDR type became distorted severely by the sintering process, but the ribs with symmetric geometry such as honeycomb and waffle type maintained their green state morphology. After sintering, the ribs were coated with green phosphor using osmosis coating process and its luminance characteristics were evaluated. The results indicated that the luminance and its efficiency is improved by using closed-cell type ribs with the new phosphor forming technology.

  14. Barrier Li Quantum Dots in Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    LIUYi-Min; LIXiao-Zhu; YANWen-Hong; BAOCheng-Guang

    2003-01-01

    The methods for the few-body system are introduced to investigate the states of the barrier Li quantum dots (QDs) in an arbitrary strength of magnetic field. The configuration, which consists of a positive ion located on the z-axis at a distaneed from the two-dimensional QD plane (the x-y plane) and three electrons in the dot plane bound by the positive ion, is called a barrier Li center. The system, which consists of three electrons in the dot plane bound by the ion,is called a barrier Li QD. The dependence of energy of the state of the barrier Li QD on an external magnetic field B and the distance d is obtained. The angular momentum L of the ground states is found to jump not only with the variation orB but also with d.

  15. Barrier Li Quantum Dots in Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    LIU Yi-Min; LI Xiao-Zhu; YAN Wen-Hong; BAO Cheng-Guang

    2003-01-01

    The methods for the few-body system are introduced to investigate the states of the barrier Li quantumdots (QDs) in an arbitrary strength of magnetic field. The configuration, which consists of a positive ion located on thez-axis at a distance d from the two-dimensional QD plane (the x-y plane) and three electrons in the dot plane boundby the positive ion, is called a barrier Li center. The system, which consists of three electrons in the dot plane bound bythe ion, is called a barrier Li QD. The dependence of energy of the state of the barrier Li QD on an external magneticfield B and the distance d is obtained. The angular momentum L of the ground states is found to jump not only withthe variation of B but also with d.

  16. Arginase 1: an unexpected mediator of pulmonary capillary barrier dysfunction in models of acute lung injury

    Directory of Open Access Journals (Sweden)

    Rudolf eLucas

    2013-08-01

    Full Text Available The integrity of epithelial and endothelial barriers in the lower airspaces of the lungs has to be tightly regulated, in order to prevent leakage and to assure efficient gas exchange between the alveoli and capillaries. Both G- and G+ bacterial toxins, such as LPS and pneumolysin, respectively, can be released in high concentrations within the pulmonary compartments upon antibiotic treatment of patients suffering from acute respiratory distress syndrome (ARDS or severe pneumonia. These toxins are able to impair endothelial barrier function, either directly, or indirectly, by induction of pro-inflammatory mediators and neutrophil sequestration. Toxin-induced endothelial hyperpermeability can involve myosin light chain phosphorylation and/or microtubule rearrangement. Endothelial nitric oxide synthase (eNOS was proposed to be a guardian of basal barrier function, since eNOS knock-out mice display an impaired expression of inter-endothelial junction proteins and as such an increased vascular permeability, as compared to wild type mice. The enzyme arginase, the activity of which can be regulated by the redox status of the cell, exists in two isoforms - arginase 1 (cytosolic and arginase 2 (mitochondrial - both of which can be expressed in lung microvascular endothelial cells. Upon activation, arginase competes with eNOS for the substrate L-arginine, as such impairing eNOS-dependent NO generation and promoting ROS generation by the enzyme. This mini-review will discuss recent findings regarding the interaction between bacterial toxins and arginase during acute lung injury and will as such address the role of arginase in bacterial toxin-induced pulmonary endothelial barrier dysfunction.

  17. Arginase 1: an unexpected mediator of pulmonary capillary barrier dysfunction in models of acute lung injury.

    Science.gov (United States)

    Lucas, Rudolf; Czikora, Istvàn; Sridhar, Supriya; Zemskov, Evgeny A; Oseghale, Aluya; Circo, Sebastian; Cederbaum, Stephen D; Chakraborty, Trinad; Fulton, David J; Caldwell, Robert W; Romero, Maritza J

    2013-01-01

    The integrity of epithelial and endothelial barriers in the lower airspaces of the lungs has to be tightly regulated, in order to prevent leakage and to assure efficient gas exchange between the alveoli and capillaries. Both G(-) and G(+) bacterial toxins, such as lipopolysaccharide and pneumolysin, respectively, can be released in high concentrations within the pulmonary compartments upon antibiotic treatment of patients suffering from acute respiratory distress syndrome (ARDS) or severe pneumonia. These toxins are able to impair endothelial barrier function, either directly, or indirectly, by induction of pro-inflammatory mediators and neutrophil sequestration. Toxin-induced endothelial hyperpermeability can involve myosin light chain phosphorylation and/or microtubule rearrangement. Endothelial nitric oxide synthase (eNOS) was proposed to be a guardian of basal barrier function, since eNOS knock-out mice display an impaired expression of inter-endothelial junction proteins and as such an increased vascular permeability, as compared to wild type mice. The enzyme arginase, the activity of which can be regulated by the redox status of the cell, exists in two isoforms - arginase 1 (cytosolic) and arginase 2 (mitochondrial) - both of which can be expressed in lung microvascular endothelial cells. Upon activation, arginase competes with eNOS for the substrate l-arginine, as such impairing eNOS-dependent NO generation and promoting reactive oxygen species generation by the enzyme. This mini-review will discuss recent findings regarding the interaction between bacterial toxins and arginase during acute lung injury and will as such address the role of arginase in bacterial toxin-induced pulmonary endothelial barrier dysfunction. PMID:23966993

  18. Computational micro-scale model of control of extravascular water and capillary perfusion in the air blood barrier.

    Science.gov (United States)

    Mazzuca, Enrico; Aliverti, Andrea; Miserocchi, Giuseppe

    2016-07-01

    A computational model of a morphologically-based alveolar capillary unit (ACU) in the rabbit is developed to relate lung fluid balance to mechanical forces between capillary surface and interstitium during development of interstitial edema. We hypothesize that positive values of interstitial liquid pressure Pliq impact on capillary transmural pressure and on blood flow. ACU blood flow, capillary recruitment and filtration are computed by modulating vascular and interstitial pressures. Model results are compared with experimental data of Pliq increasing from ~-10 (control) up to ~4cmH2O in two conditions, hypoxia and collagenase injection. For hypoxia exposure, fitting data requires a linear increase in hydraulic conductivity Lp and capillary pressure PC, that fulfils the need of increase in oxygen delivery. For severe fragmentation of capillary endothelial barrier (collagenase injection), fitting requires a rapid increase in both hydraulic and protein permeability, causing ACU de-recruitment, followed by an increase in PC as a late response to restore blood flow. In conclusion, the model allows to describe the lung adaptive response to edemagenic perturbations; the increase in Pliq, related to the low interstitial compliance, provides an efficient control of extravascular water, by limiting microvascular filtration.

  19. Computational micro-scale model of control of extravascular water and capillary perfusion in the air blood barrier.

    Science.gov (United States)

    Mazzuca, Enrico; Aliverti, Andrea; Miserocchi, Giuseppe

    2016-07-01

    A computational model of a morphologically-based alveolar capillary unit (ACU) in the rabbit is developed to relate lung fluid balance to mechanical forces between capillary surface and interstitium during development of interstitial edema. We hypothesize that positive values of interstitial liquid pressure Pliq impact on capillary transmural pressure and on blood flow. ACU blood flow, capillary recruitment and filtration are computed by modulating vascular and interstitial pressures. Model results are compared with experimental data of Pliq increasing from ~-10 (control) up to ~4cmH2O in two conditions, hypoxia and collagenase injection. For hypoxia exposure, fitting data requires a linear increase in hydraulic conductivity Lp and capillary pressure PC, that fulfils the need of increase in oxygen delivery. For severe fragmentation of capillary endothelial barrier (collagenase injection), fitting requires a rapid increase in both hydraulic and protein permeability, causing ACU de-recruitment, followed by an increase in PC as a late response to restore blood flow. In conclusion, the model allows to describe the lung adaptive response to edemagenic perturbations; the increase in Pliq, related to the low interstitial compliance, provides an efficient control of extravascular water, by limiting microvascular filtration. PMID:27059893

  20. A novel cold plasma jet generated by capillary atmospheric dielectric barrier discharge

    International Nuclear Information System (INIS)

    An easy-operated and effective scheme is presented to generate a novel kind of atmospheric cold plasma millimeter jet. The jet operates with many kinds of working gas at atmosphere pressure, such as Ar, He and N2, in a capillary quartz dielectric barrier discharge (DBD) system powered by a pulsed power source with a frequency of 33 kHz and variable voltage of 1-12 kV. Via a CCD imager, the initial discharge filaments in the DBD gap are found to be transformed into diffusion discharge or glow-like discharge by the flowing gas through the DBD gap, and a plasma jet formed in the outlet of the capillary is viewed simultaneously. The critical velocity of the gas flow for the plasma jet formation is determined to be 3-8 m/s for different working gases by a well-designed enthalpy probe. The jet range for a special gas can be changed by the increase of the gas flow velocity while the jet range for different gases varies a lot and the helium jet takes the longest range of about 44 mm when the helium flows at a velocity of about 20 m/s. Beyond the velocity limit of 20 m/s for laminar helium flow, the jet of helium plasma becomes torrent and unstable and its range turns shorter. Based on the OES analysis of He plasma jets, it is determined that the excitation temperature of He jets lay in the range 2000 K-3000 K, which is much lower than the excitation temperature of a normal arc plasma torch and hints that the jet is cold especially when compared to the arc plasma torch. (authors)

  1. A capillary network model for coupled gas and water flow in engineered barriers

    International Nuclear Information System (INIS)

    A two-dimensional capillary network model for gas migration through a water-saturated medium is presented. The model is an extension of previously developed capillary bundle models, and provides a discrete alternative to classical continuum Darcy models. The need for such an alternative has become apparent from recent experimental results that suggest gas migrates through low permeability water-saturated media via a small number of preferential pathways

  2. The Effects of Alcohol Abuse on Pulmonary Alveolar-Capillary Barrier Function in Humans

    OpenAIRE

    Burnham, Ellen L.; Halkar, Raghuveer; Burks, Marsha; Moss, Marc

    2008-01-01

    Aims: Alcohol abuse is associated with the development of the acute respiratory distress syndrome, a disorder characterized by abnormal alveolar-capillary permeability. We hypothesized that individuals with a history of alcohol abuse would have clinical evidence of abnormal alveolar-capillary permeability even in the absence of symptoms. This could contribute to their propensity for the development of this disorder. Methods: Thirty-three subjects with a history of alcohol abuse, but no other ...

  3. Dynamic 99mTc-DTPA radioaerosol lung scanning for the evaluation of alveolar-capillary barrier permeability

    International Nuclear Information System (INIS)

    Pulmonary clearance of small droplet 99mTc-DTPA radioaerosol was studied in 100 patients (12 normal subjects, N; 10 asymptomatic healthy smoker, FA; 31 patients with interstitial lung diseases, IP; 47 patients with chronic obstructive lung disease, BPCO). The first seven minutes of clearance were described with the function At=Ao*exp(-K*t) and the time constant K was considered representative of the 99mTc-DTPA clearance rate and hence of the alveolar-capillary barrier permeability. Groups FA, IP and BPCO showed a significant (p99mTc-DTPA dynamic lung scanning is an easy, non-invasive method to assess derangements of alveolar-capillary barrier permeability secondary to epithelial damage; 2) permeability increase is a very early effect of cigarette smoke damafe to the epithelium; 3) other mechanisms of epithelial injury are present in diffuse lung disease; 4) while the clinical role of this new pathophysiological test is not yet clear, it is likely that it may become a very early marker of pulmonary epithelial damage in diffuse lung disease

  4. Prototype Engineered Barrier System Field Tests (PEBSFT)

    International Nuclear Information System (INIS)

    This progress report presents the interpretation of data obtained (up to November 1, 1988) from the Prototype Engineered Barrier System Field Tests (PEBSFT) that are being performed for the Yucca Mountain Project (YMP) in G-Tunnel within the Nevada Test site. The PEBSFTs are being conducted to evaluate the applicability of measurement techniques, numerical models, and procedures developed for the field tests for future investigations that will be conducted in the Exploratory Shaft Facilities, at a potential high-level radioactive waste repository site in Yucca Mountain. The primary objective of the tests is to provide the basis for determining whether tests planned for Yucca Mountain have the potential to be successful. Thirteen chapters discuss the following: mapping the electromagnetic permittivity and attenuation rate of the rock mass; changes in moisture content detected by the neutron logging probe; characterization of the in-situ permeability of the fractured tuff around the heater borehole; electrical resistance heater installed in a 30-cm borehole; relative humidity measurements; the operation, design, construction, calibration, and installation of a microwave circuit that might provide partial pressure information at temperatures in excess of 200 degree C (392 degree F); pressure and temperature measurements in the G-Tunnel; the moisture collection system, which attempts to collect steam that migrates into the heater borehole; The borehole television and borescope surveys that were performed to map the location, orientation, and aperture of the fractures intersecting the boreholes; preliminary scoping calculations of the hydrothermal conditions expected for this prototype test; the Data Acquisition System; and the results of the PEBSFT, preliminary interpretations of these results, and plans for the remainder of the test. Chapters have been indexed separately for inclusion on the data base

  5. Physical and numerical modeling of an inclined three-layer (silt/gravelly sand/clay) capillary barrier cover system under extreme rainfall.

    Science.gov (United States)

    Ng, Charles W W; Liu, Jian; Chen, Rui; Xu, Jie

    2015-04-01

    As an extension of the two-layer capillary barrier, a three-layer capillary barrier landfill cover system is proposed for minimizing rainfall infiltration in humid climates. This system consists of a compacted clay layer lying beneath a conventional cover with capillary barrier effects (CCBE), which is in turn composed of a silt layer sitting on top of a gravelly sand layer. To explore the effectiveness of the new system in minimizing rainfall infiltration, a flume model (3.0 m × 1.0 m × 1.1 m) was designed and set up in this study. This physical model was heavily instrumented to monitor pore water pressure, volumetric water content, surface runoff, infiltration and lateral drainage of each layer, and percolation of the cover system. The cover system was subjected to extreme rainfall followed by evaporation. The experiment was also back-analyzed using a piece of finite element software called CODE_BRIGHT to simulate transient water flows in the test. Based on the results obtained from various instruments, it was found that breakthrough of the two upper layers occurred for a 4-h rainfall event having a 100-year return period. Due to the presence of the newly introduced clay layer, the percolation of the three-layer capillary barrier cover system was insignificant because the clay layer enabled lateral diversion in the gravelly sand layer above. In other words, the gravelly sand layer changed from being a capillary barrier in a convention CCBE cover to being a lateral diversion passage after the breakthrough of the two upper layers. Experimental and back-analysis results confirm that no infiltrated water seeped through the proposed three-layer barrier system. The proposed system thus represents a promising alternative landfill cover system for use in humid climates. PMID:25582391

  6. Regulation and repair of the alveolar-capillary barrier in acute lung injury.

    Science.gov (United States)

    Bhattacharya, Jahar; Matthay, Michael A

    2013-01-01

    Considerable progress has been made in understanding the basic mechanisms that regulate fluid and protein exchange across the endothelial and epithelial barriers of the lung under both normal and pathological conditions. Clinically relevant lung injury occurs most commonly from severe viral and bacterial infections, aspiration syndromes, and severe shock. The mechanisms of lung injury have been identified in both experimental and clinical studies. Recovery from lung injury requires the reestablishment of an intact endothelial barrier and a functional alveolar epithelial barrier capable of secreting surfactant and removing alveolar edema fluid. Repair mechanisms include the participation of endogenous progenitor cells in strategically located niches in the lung. Novel treatment strategies include the possibility of cell-based therapy that may reduce the severity of lung injury and enhance lung repair. PMID:23398155

  7. Field testing of asphalt-emulsion radon-barrier system

    International Nuclear Information System (INIS)

    Three years of laboratory and field testing have demonstrated that asphalt emulsion seals are effective radon diffusion barriers. Both laboratory and field tests in 1979, 1980 and 1981 have shown that an asphalt emulsion seal can reduce radon fluxes by greater than 99.9%. The effective diffusion coefficient for the various asphalt emulsion admix seals averages about 10-6 cm2/s. The 1981 joint field test is a culmination of all the technology developed to date for asphalt emulsion radon barrier systems. Preliminary results of this field test and the results of the 1980 field test are presented. 18 figures, 6 tables

  8. Direct probing of Schottky barriers in Si nanowire Schottky barrier field effect transistors.

    Science.gov (United States)

    Martin, Dominik; Heinzig, Andre; Grube, Matthias; Geelhaar, Lutz; Mikolajick, Thomas; Riechert, Henning; Weber, Walter M

    2011-11-18

    This work elucidates the role of the Schottky junction in the electronic transport of nanometer-scale transistors. In the example of Schottky barrier silicon nanowire field effect transistors, an electrical scanning probe technique is applied to examine the charge transport effects of a nanometer-scale local top gate during operation. The results prove experimentally that Schottky barriers control the charge carrier transport in these devices. In addition, a proof of concept for a reprogrammable nonvolatile memory device based on band bending at the Schottky barriers will be shown.

  9. Ozone generation in a kHz-pulsed He-O2 capillary dielectric barrier discharge operated in ambient air

    Science.gov (United States)

    Sands, Brian L.; Ganguly, Biswa N.

    2013-12-01

    The generation of reactive oxygen species using nonequilibrium atmospheric pressure plasma jet devices has been a subject of recent interest due to their ability to generate localized concentrations from a compact source. To date, such studies with plasma jet devices have primarily utilized radio-frequency excitation. In this work, we characterize ozone generation in a kHz-pulsed capillary dielectric barrier discharge configuration comprised of an active discharge plasma jet operating in ambient air that is externally grounded. The plasma jet flow gas was composed of helium with an admixture of up to 5% oxygen. A unipolar voltage pulse train with a 20 ns pulse risetime was used to drive the discharge at repetition rates between 2-25 kHz. Using UVLED absorption spectroscopy centered at 255 nm near the Hartley-band absorption peak, ozone was detected over 1 cm from the capillary axis. We observed roughly linear scaling of ozone production with increasing pulse repetition rate up to a "turnover frequency," beyond which ozone production steadily dropped and discharge current and 777 nm O(5P→5S°) emission sharply increased. The turnover in ozone production occurred at higher pulse frequencies with increasing flow rate and decreasing applied voltage with a common energy density of 55 mJ/cm3 supplied to the discharge. The limiting energy density and peak ozone production both increased with increasing O2 admixture. The power dissipated in the discharge was obtained from circuit current and voltage measurements using a modified parallel plate dielectric barrier discharge circuit model and the volume-averaged ozone concentration was derived from a 2D ozone absorption measurement. From these measurements, the volume-averaged efficiency of ozone production was calculated to be 23 g/kWh at conditions for peak ozone production of 41 mg/h at 11 kV applied voltage, 3% O2, 2 l/min flow rate, and 13 kHz pulse repetition rate, with 1.79 W dissipated in the discharge.

  10. On ultrasound-induced microbubble oscillation in a capillary blood vessel and its implications for the blood-brain barrier

    Science.gov (United States)

    Wiedemair, W.; Tuković, Ž.; Jasak, H.; Poulikakos, D.; Kurtcuoglu, V.

    2012-02-01

    The complex interaction between an ultrasound-driven microbubble and an enclosing capillary microvessel is investigated by means of a coupled, multi-domain numerical model using the finite volume formulation. This system is of interest in the study of transient blood-brain barrier disruption (BBBD) for drug delivery applications. The compliant vessel structure is incorporated explicitly as a distinct domain described by a dedicated physical model. Red blood cells (RBCs) are taken into account as elastic solids in the blood plasma. We report the temporal and spatial development of transmural pressure (Ptm) and wall shear stress (WSS) at the luminal endothelial interface, both of which are candidates for the yet unknown mediator of BBBD. The explicit introduction of RBCs shapes the Ptm and WSS distributions and their derivatives markedly. While the peak values of these mechanical wall parameters are not affected considerably by the presence of RBCs, a pronounced increase in their spatial gradients is observed compared to a configuration with blood plasma alone. The novelty of our work lies in the explicit treatment of the vessel wall, and in the modelling of blood as a composite fluid, which we show to be relevant for the mechanical processes at the endothelium.

  11. In-situ studies on the performance of landfill caps (compacted soil liners, geomembranes, geosynthetic clay liners, capillary barriers)

    Energy Technology Data Exchange (ETDEWEB)

    Melchior, S. [IGB - Ingenieurbuero fuer Grundbau, Hamburg (Germany)

    1997-12-31

    Since 1986 different types of landfill covers have been studied in-situ on the Georgswerder landfill in Hamburg, Germany. Water balance data are available for eight years. The performance of different carriers has been measured by collecting the leakage on areas ranging from 100 m{sup 2} to 500 m{sup 2}. Composite liners with geomembranes performed best, showing no leakage. An extended capillary barrier also performed well. The performance of compacted soil liners, however, decreased severely within five years due to desiccation, shrinkage and plant root penetration (liner leakage now ranging from 150 mm/a to 200 mm/a). About 50 % of the water that reaches the surface of the liner is leaking through it. The maximum leakage rates have increased from 2 x 10{sup -10} m{sup 3} m{sup -2} s{sup -1} to 4 x 10{sup -8} m{sup 3} m{sup -2} s{sup -1}. Two types of geosynthetic clay liners (GCL) have been tested for two years now with disappointing results. The GCL desiccated during the first dry summer of the study. High percolation rates through the GCL were measured during the following winter (45 mm resp. 63 mm in four months). Wetting of the GCL did not significantly reduce the percolation rates.

  12. Constant pressure-assisted head-column field-amplified sample injection in combination with in-capillary derivatization for enhancing the sensitivity of capillary electrophoresis.

    Science.gov (United States)

    Yan, Na; Zhou, Lei; Zhu, Zaifang; Zhang, Huige; Zhou, Ximin; Chen, Xingguo

    2009-05-15

    In this work, a novel method combining constant pressure-assisted head-column field-amplified sample injection (PA-HC-FASI) with in-capillary derivatization was developed for enhancing the sensitivity of capillary electrophoresis. PA-HC-FASI uses an appropriate positive pressure to counterbalance the electroosmotic flow in the capillary column during electrokinetic injection, while taking advantage of the field amplification in the sample matrix and the water of the "head column". Accordingly, the analytes were stacked at the stationary boundary between water and background electrolyte. After 600s PA-HC-FASI, 4-fluoro-7-nitro-2,1,3-benzoxadiazole as derivatization reagent was injected, followed by an electrokinetic step (5kV, 45s) to enhance the mixing efficiency of analytes and reagent plugs. Standing a specified time of 10min for derivatization reaction under 35 degrees C, then the capillary temperature was cooled to 25 degrees C and the derivatives were immediately separated and determined under 25 degrees C. By investigating the variables of the presented approach in detail, on-line preconcentration, derivatization and separation could be automatically operated in one run and required no modification of current CE commercial instrument. Moreover, the sensitivity enhancement factor of 520 and 800 together with the detection limits of 16.32 and 6.34pg/mL was achieved for model compounds: glufosinate and aminomethylphosphonic acid, demonstrating the high detection sensitivity of the presented method. PMID:19342058

  13. Combined effect of capillary barrier and layered slope on water, solute and nanoparticle transfer in an unsaturated soil at lysimeter scale.

    Science.gov (United States)

    Prédélus, Dieuseul; Coutinho, Artur Paiva; Lassabatere, Laurent; Bien, Le Binh; Winiarski, Thierry; Angulo-Jaramillo, Rafael

    2015-10-01

    It is well recognized that colloidal nanoparticles are highly mobile in soils and can facilitate the transport of contaminants through the vadose zone. This work presents the combined effect of the capillary barrier and soil layer slope on the transport of water, bromide and nanoparticles through an unsaturated soil. Experiments were performed in a lysimeter (1×1×1.6m(3)) called LUGH (Lysimeter for Urban Groundwater Hydrology). The LUGH has 15 outputs that identify the temporal and spatial evolution of water flow, solute flux and nanoparticles in relation to the soil surface conditions and the 3D system configuration. Two different soil structures were set up in the lysimeter. The first structure comprises a layer of sand (0-0.2cm, in diameter) 35cm thick placed horizontally above a layer of bimodal mixture also 35cm thick to create a capillary barrier at the interface between the sand and bimodal material. The bimodal material is composed of a mixture 50% by weight of sand and gravel (0.4-1.1cm, in diameter). The second structure, using the same amount of sand and bimodal mixture as the first structure represents an interface with a 25% slope. A 3D numerical model based on Richards equation for flow and the convection dispersion equations coupled with a mechanical module for nanoparticle trapping was developed. The results showed that under the effect of the capillary barrier, water accumulated at the interface of the two materials. The sloped structure deflects flow in contrast to the structure with zero slope. Approximately 80% of nanoparticles are retained in the lysimeter, with a greater retention at the interface of two materials. Finally, the model makes a good reproduction of physical mechanisms observed and appears to be a useful tool for identifying key processes leading to a better understanding of the effect of capillary barrier on nanoparticle transfer in an unsaturated heterogeneous soil. PMID:26184062

  14. Additional electric field in real trench MOS barrier Schottky diode

    Science.gov (United States)

    Mamedov, R. K.; Aslanova, A. R.

    2016-04-01

    In real trench MOS barrier Schottky diode (TMBS diode) additional electric field (AEF) the whole is formed in the near contact region of the semiconductor and its propagation space is limited with the barrier metal and the metallic electrodes of MOS structures. Effective potential barrier height TMBS diode is formed via resulting electric field of superposition AEF and electric field of space charge region (SCR) semiconductor. The dependence of the resulting electric field intensity of the distance towards the inside the semiconductor is nonlinear and characterized by a peak at a certain distance from the interface. The thickness of the SCR in TMBS diode becomes equal to the trench depth. Force and energy parameters of the AEF, and thus resulting electric field in the SCR region, become dependent on the geometric design parameters TMBS diode. The forward I-V characteristic TMBS diode is described by the thermionic emission theory as in conventional flat Scottky diode, and in the reverse bias, current is virtually absent at initial voltage, appears abruptly at a certain critical voltage.

  15. Superparamagnetic particle dynamics and mixing in a rotating capillary tube with a stationary magnetic field.

    Science.gov (United States)

    Lee, Jun-Tae; Abid, Aamir; Cheung, Ka Ho; Sudheendra, L; Kennedy, Ian M

    2012-09-01

    The dynamics of superparamagnetic particles subject to competing magnetic and viscous drag forces have been examined with a uniform, stationary, external magnetic field. In this approach, competing drag and magnetic forces were created in a fluid suspension of superparamagnetic particles that was confined in a capillary tube; competing viscous drag and magnetic forces were established by rotating the tube. A critical Mason number was determined for conditions under which the rotation of the capillary prevents the formation of chains from individual particles. The statistics of chain length were investigated by image analysis while varying parameters such as the rotation speed and the viscosity of the liquid. The measurements showed that the rate of particle chain formation was decreased with increased viscosity and rotation speed ; the particle dynamics could be quantified by the same dimensionless Mason number that has been demonstrated for rotating magnetic fields. The potential for enhancement of mixing in a bioassay was assessed using a fast chemical reaction that was diffusion-limited. Reducing the Mason below the critical value, so that chains were formed in the fluid, gave rise to a modest improvement in the time to completion of the reaction. PMID:23066382

  16. Determination of ephedrine and pseudoephedrine by field-amplified sample injection capillary electrophoresis.

    Science.gov (United States)

    Deng, Dongli; Deng, Hao; Zhang, Lichun; Su, Yingying

    2014-04-01

    A simple and rapid capillary electrophoresis method was developed for the separation and determination of ephedrine (E) and pseudoephedrine (PE) in a buffer solution containing 80 mM of NaH2PO4 (pH 3.0), 15 mM of β-cyclodextrin and 0.3% of hydroxypropyl methylcellulose. The field-amplified sample injection (FASI) technique was applied to the online concentration of the alkaloids. With FASI in the presence of a low conductivity solvent plug (water), an approximately 1,000-fold improvement in sensitivity was achieved without any loss of separation efficiency when compared to conventional sample injection. Under these optimized conditions, a baseline separation of the two analytes was achieved within 16 min and the detection limits for E and PE were 0.7 and 0.6 µg/L, respectively. Without expensive instruments or labeling of the compounds, the limits of detection for E and PE obtained by the proposed method are comparable with (or even lower than) those obtained by capillary electrophoresis laser-induced fluorescence, liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. The method was validated in terms of precision, linearity and accuracy, and successfully applied for the determination of the two alkaloids in Ephedra herbs.

  17. Phase-field study of crystal growth in three-dimensional capillaries: Effects of crystalline anisotropy

    Science.gov (United States)

    Debierre, Jean-Marc; Guérin, Rahma; Kassner, Klaus

    2016-07-01

    Phase-field simulations are performed to explore the thermal solidification of a pure melt in three-dimensional capillaries. Motivated by our previous work for isotropic or slightly anisotropic materials, we focus here on the more general case of anisotropic materials. Different channel cross sections are compared (square, hexagonal, circular) to reveal the influence of geometry and the effects of a competition between the crystal and the channel symmetries. In particular, a compass effect toward growth directions favored by the surface energy is identified. At given undercooling and anisotropy, the simulations generally show the coexistence of several growth modes. The relative stability of these growth modes is tested by submitting them to a strong spatiotemporal noise for a short time, which reveals a subtle hierarchy between them. Similarities and differences with experimental growth modes in confined geometry are discussed qualitatively.

  18. Synthesis and deposition of basement membrane proteins by primary brain capillary endothelial cells in a murine model of the blood-brain barrier

    DEFF Research Database (Denmark)

    Thomsen, Maj Schneider; Birkelund, Svend; Burkhart, Annette;

    2016-01-01

    The brain vascular basement membrane is important for both blood-brain barrier (BBB) development, stability, and barrier integrity and the contribution hereto from brain capillary endothelial cells (BCECs), pericytes, and astrocytes of the BBB is probably significant. The aim of the present study......-culture, in co-culture with pericytes or mixed glial cells, or as a triple-culture with both pericytes and mixed glial cells. The integrity of the BBB models was validated by measures of transendothelial electrical resistance (TEER) and passive permeability to mannitol. The expression of basement membrane...... proteins was analysed using RT-qPCR, mass spectrometry, and immunocytochemistry. Co-culturing mBCECs with pericytes, mixed glial cells, or both significantly increased the TEER compared to the mono-culture, and a low passive permeability was correlated with high TEER. The mBCECs expressed all major...

  19. Field Lysimeter Test Facility for protective barriers: Experimental plan

    International Nuclear Information System (INIS)

    This document was first written in October 1986 and has been used to guide the design of the Field Lysimeter Test Facility (FLTF) and to promote discussions between research and engineering staff regarding the selection of barrier treatments for inclusion in the FLTF. The construction of the lysimeter facility was completed June 28, 1987. This document describes the facility, the treatments placed in each lysimeter, types of measurements made in each lysimeter, and a brief discussion of project activities related to quality assurance, safety, and funding requirements. The treatment description and figures have been updated to reflect the lysimeter facility as constructed. 12 refs., 6 figs., 5 tabs

  20. Conceptual design and sample preparation of electrode covered single glass macro-capillaries for studying the effect of an external electric field on particle guiding

    Energy Technology Data Exchange (ETDEWEB)

    Wartak, A. [Institute of Applied Physics, TU Wien, A-1040 Vienna (Austria); Bereczky, R.J., E-mail: bereczky.reka@atomki.mta.hu [Institute for Nuclear Research, Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen, P.O. Box 51 (Hungary); Kowarik, G. [Institute of Applied Physics, TU Wien, A-1040 Vienna (Austria); Tőkési, K. [Institute for Nuclear Research, Hungarian Academy of Sciences (ATOMKI), H-4026 Debrecen, P.O. Box 51 (Hungary); Aumayr, F. [Institute of Applied Physics, TU Wien, A-1040 Vienna (Austria)

    2015-07-01

    We present the design and construction of a macroscopic glass capillary covered by electrodes on the outside. With these new capillary targets it will be possible to study the influence of an external electric field on the process of guiding of charged particles through a capillary. The new degrees of freedoms will contribute to both a better fundamental understanding of the guiding phenomenon but might also be of use in practical applications.

  1. Capillary rise quantification by field injection of artificial deuterium and laboratory soil characterization

    Directory of Open Access Journals (Sweden)

    O. Grünberger

    2010-10-01

    Full Text Available In arid contexts, water rises from the saturated level of a shallow aquifer to the drying soil surface where evaporation takes place. This process plays important roles in terms of plant survival, salt balance and aquifer budget. A new field quantification method of this capillary rise flow is proposed using micro-injections (6 μL of deuterium-enriched solution (δ value of 63 000‰ vs. V-SMOW into unsatured soil at 1 m depth. Evaluation of peak displacement from a profile sampling 35 days later, delivered estimates that were compared with outputs of numerical simulation based on laboratory hydrodynamic measurements. A rate of 3.7 cm y−1 was observed in a Moroccan site where the aquifer level was 2.44 m deep. This value was higher, than other estimates based on natural diffusion with the same depth of aquifer, but lower than the estimates established using integration of van Genutchen closed-form functions for soil hydraulic conductivity and retention curve.

  2. Far field effects of complex noise barrier reflections

    NARCIS (Netherlands)

    Lutgendorf, D.; Wessels, P.W.; Eerden, F.J.M. van den; Roo, F. de

    2012-01-01

    Within the EU FP7 QUIESST project, QUIeting the Environment for a Sustainable Surface Transport, a test method is being developed for the reflectivity of noise barriers. The method needs to account for a complex shape of barriers and the use of various types of absorbing materials. The performance o

  3. High-resolution wide-field imaging of perfused capillaries without the use of contrast agent

    Directory of Open Access Journals (Sweden)

    Nelson DA

    2011-08-01

    Full Text Available Darin A Nelson1, Zvia Burgansky-Eliash1,2, Hila Barash1, Anat Loewenstein3, Adiel Barak4, Elisha Bartov2, Tali Rock2, Amiram Grinvald51Optical Imaging Ltd, Rehovot, Israel; 2Department of Ophthalmology, Edith Wolfson Medical Center, Holon, Israel; 3Department of Ophthalmology, Tel Aviv Medical Center & Sackler Faculty of Medicine, Tel Aviv University, Israel; 4Department of Ophthalmology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; 5Department of Neurobiology, The Weizmann Institute of Science, Rehovot, IsraelPurpose: Assessment of capillary abnormalities facilitates early diagnosis, treatment, and follow-up of common retinal pathologies. Injected contrast agents like fluorescein are widely used to image retinal capillaries, but this highly effective procedure has a few disadvantages, such as untoward side effects, inconvenience of injection, and brevity of the time window for clear visualization. The retinal function imager (RFI is a tool for monitoring retinal functions, such as blood velocity and oximetry, based on intrinsic signals. Here we describe the clinical use of hemoglobin in red blood cells (RBCs as an intrinsic motion-contrast agent in the generation of detailed noninvasive capillary-perfusion maps (nCPMs.Patients and methods: Multiple series of nCPM images were acquired from 130 patients with diabetic retinopathy, vein occlusion, central serous retinopathy, age-related macular degeneration, or metabolic syndrome, as well as from 37 healthy subjects. After registration, pixel value distribution parameters were analyzed to locate RBC motion.Results: The RFI yielded nCPMs demonstrating microvascular morphology including capillaries in exquisite detail. Maps from the same subject were highly reproducible in repeated measurements, in as much detail and often better than that revealed by the very best fluorescein angiography. In patients, neovascularization and capillary nonperfusion areas were clearly observed. Foveal avascular

  4. Tilting oil-water contact in the chalk of Tyra Field as interpreted from capillary pressure data

    DEFF Research Database (Denmark)

    Fabricius, Ida Lykke; Rana, M.A.

    2010-01-01

    The Tyra Field in the central North Sea is located in Palaeogene and Upper Cretaceous chalk. It contains a natural gas zone underlain by an oil leg. Based on analysis of logs and core data from ten wells drilled prior to the field being put into production, normalized water saturation depth......-trends from logs were compared with normalized water saturation depth-trends predicted from capillary pressure core data. The ten wells lie close to a SW–NE cross section of the field. For the gas–oil contact, a free contact measured in one well corresponds to a practically horizontal contact interpreted from...... logging data in the remaining wells. A westerly dipping oil–water contact was found from logging data. Comparison of the depth-wise trends in normalized water saturation among the different wells indicates a regional pattern: in the western side of the field, the trends correspond to a situation...

  5. Oxidative stress pathways involved in cytotoxicity and genotoxicity of titanium dioxide (TiO2) nanoparticles on cells constitutive of alveolo-capillary barrier in vitro.

    Science.gov (United States)

    Hanot-Roy, Maïté; Tubeuf, Emilie; Guilbert, Ariane; Bado-Nilles, Anne; Vigneron, Pascale; Trouiller, Bénédicte; Braun, Anne; Lacroix, Ghislaine

    2016-06-01

    The health risks of nanoparticles remain a serious concern given their prevalence from industrial and domestic use. The primary route of titanium dioxide nanoparticle exposure is inhalation. The extent to which nanoparticles contribute to cellular toxicity is known to associate induction of oxidative stress. To investigate this problem further, the effect of titanium dioxide nanoparticles was examined on cell lines representative of alveolo-capillary barrier. The present study showed that all nanoparticle-exposed cell lines displayed ROS generation. Macrophage-like THP-1 and HPMEC-ST1.6R microvascular cells were sensitive to endogenous redox changes and underwent apoptosis, but not alveolar epithelial A549 cells. Genotoxic potential of titanium dioxide nanoparticles was investigated using the activation of γH2AX, activation of DNA repair proteins and cell cycle arrest. In the sensitive cell lines, DNA damage was persistent and activation of DNA repair pathways was observed. Moreover, western blot analysis showed that specific pathways associated with cellular stress response were activated concomitantly with DNA repair or apoptosis. Nanoparticles-induced oxidative stress is finally signal transducer for further physiological effects including genotoxicity and cytotoxicity. Within activated pathways, HSP27 and SAPK/JNK proteins appeared as potential biomarkers of intracellular stress and of sensitivity to endogenous redox changes, respectively, enabling to predict cell behavior.

  6. Oxidative stress pathways involved in cytotoxicity and genotoxicity of titanium dioxide (TiO2) nanoparticles on cells constitutive of alveolo-capillary barrier in vitro.

    Science.gov (United States)

    Hanot-Roy, Maïté; Tubeuf, Emilie; Guilbert, Ariane; Bado-Nilles, Anne; Vigneron, Pascale; Trouiller, Bénédicte; Braun, Anne; Lacroix, Ghislaine

    2016-06-01

    The health risks of nanoparticles remain a serious concern given their prevalence from industrial and domestic use. The primary route of titanium dioxide nanoparticle exposure is inhalation. The extent to which nanoparticles contribute to cellular toxicity is known to associate induction of oxidative stress. To investigate this problem further, the effect of titanium dioxide nanoparticles was examined on cell lines representative of alveolo-capillary barrier. The present study showed that all nanoparticle-exposed cell lines displayed ROS generation. Macrophage-like THP-1 and HPMEC-ST1.6R microvascular cells were sensitive to endogenous redox changes and underwent apoptosis, but not alveolar epithelial A549 cells. Genotoxic potential of titanium dioxide nanoparticles was investigated using the activation of γH2AX, activation of DNA repair proteins and cell cycle arrest. In the sensitive cell lines, DNA damage was persistent and activation of DNA repair pathways was observed. Moreover, western blot analysis showed that specific pathways associated with cellular stress response were activated concomitantly with DNA repair or apoptosis. Nanoparticles-induced oxidative stress is finally signal transducer for further physiological effects including genotoxicity and cytotoxicity. Within activated pathways, HSP27 and SAPK/JNK proteins appeared as potential biomarkers of intracellular stress and of sensitivity to endogenous redox changes, respectively, enabling to predict cell behavior. PMID:26928046

  7. Laboratory and field scale demonstration of reactive barrier systems

    International Nuclear Information System (INIS)

    In an effort to devise a cost efficient technology for remediation of uranium contaminated groundwater, the Department of Energy's Uranium Mill Tailings Remedial Action (DOE-UMTRA) Program through Sandia National Laboratories (SNL) fabricated a pilot scale research project utilizing reactive subsurface barriers at an UMTRA site in Durango, Colorado. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment metallic iron) in the flow path of the contaminated groundwater. The reactive media then removes and/or transforms the contaminant(s) to regulatory acceptable levels. Experimental design and results are discussed with regard to other potential applications of reactive barrier remediation strategies at other sites with contaminated groundwater problems

  8. Gas-Filled Capillary Model

    Science.gov (United States)

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

    2006-11-01

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

  9. Renewable Energy Permitting Barriers in Hawaii: Experience from the Field

    Energy Technology Data Exchange (ETDEWEB)

    Busche, S.; Donnelly, C.; Atkins, D.; Fields, R.; Black, C.

    2013-03-01

    This white paper presents a summary of the solicited input from permitting agencies and renewable energy developers on the permitting process in Hawaii to provide stakeholders in Hawaii, particularly those involved in permitting, with information on current permitting barriers that renewable energy developers are experiencing.

  10. Exact field ionization rates in the barrier suppression-regime from numerical TDSE calculations

    OpenAIRE

    Bauer, D; Mulser, P.

    1998-01-01

    Numerically determined ionization rates for the field ionization of atomic hydrogen in strong and short laser pulses are presented. The laser pulse intensity reaches the so-called "barrier suppression ionization" regime where field ionization occurs within a few half laser cycles. Comparison of our numerical results with analytical theories frequently used shows poor agreement. An empirical formula for the "barrier suppression ionization"-rate is presented. This rate reproduces very well the ...

  11. Thermionic field emission in GaN nanoFET Schottky barriers

    International Nuclear Information System (INIS)

    A mathematical stability approach that enables the evaluation of the mulitvariate thermionic field emission parameters at Schottky barriers is presented. The method is general, requiring only the effective mass and relative dielectric constant for a given semiconductor. The approach is demonstrated in a first-time analysis of the barrier heights, tunneling probabilities and potential drops for changes in the Schottky barriers of gallium nitride nano-field effect transistors in a long-duration heavy ion radiation extreme environment. The investigation yielded fundamental insights into behavior that would be challenging to predict a priori. (paper)

  12. A large-scale electrophoresis- and chromatography-based determination of gene expression profiles in bovine brain capillary endothelial cells after the re-induction of blood-brain barrier properties

    Directory of Open Access Journals (Sweden)

    Duban-Deweer Sophie

    2010-11-01

    Full Text Available Abstract Background Brain capillary endothelial cells (BCECs form the physiological basis of the blood-brain barrier (BBB. The barrier function is (at least in part due to well-known proteins such as transporters, tight junctions and metabolic barrier proteins (e.g. monoamine oxidase, gamma glutamyltranspeptidase and P-glycoprotein. Our previous 2-dimensional gel proteome analysis had identified a large number of proteins and revealed the major role of dynamic cytoskeletal remodelling in the differentiation of bovine BCECs. The aim of the present study was to elaborate a reference proteome of Triton X-100-soluble species from bovine BCECs cultured in the well-established in vitro BBB model developed in our laboratory. Results A total of 215 protein spots (corresponding to 130 distinct proteins were identified by 2-dimensional gel electrophoresis, whereas over 350 proteins were identified by a shotgun approach. We classified around 430 distinct proteins expressed by bovine BCECs. Our large-scale gene expression analysis enabled the correction of mistakes referenced into protein databases (e.g. bovine vinculin and constitutes valuable evidence for predictions based on genome annotation. Conclusions Elaboration of a reference proteome constitutes the first step in creating a gene expression database dedicated to capillary endothelial cells displaying BBB characteristics. It improves of our knowledge of the BBB and the key proteins in cell structures, cytoskeleton organization, metabolism, detoxification and drug resistance. Moreover, our results emphasize the need for both appropriate experimental design and correct interpretation of proteome datasets.

  13. CAPILLARY PRESSURE/MERCURY INJECTION ANALYSIS: CHEROKEE AND BUG FIELDS, SAN JUAN COUNTY, UTAH

    Energy Technology Data Exchange (ETDEWEB)

    Thomas C. Chidsey Jr; David E. Eby

    2003-12-01

    Over 400 million barrels (64 million m{sup 3}) of oil have been produced from the shallow-shelf carbonate reservoirs in the Pennsylvanian (Desmoinesian) Paradox Formation in the Paradox Basin, Utah and Colorado. With the exception of the giant Greater Aneth field, the other 100 plus oil fields in the basin typically contain 2 to 10 million barrels (0.3-1.6 million m{sup 3}) of original oil in place. Most of these fields are characterized by high initial production rates followed by a very short productive life (primary), and hence premature abandonment. Only 15 to 25 percent of the original oil in place is recoverable during primary production from conventional vertical wells. An extensive and successful horizontal drilling program has been conducted in the giant Greater Aneth field. However, to date, only two horizontal wells have been drilled in small Ismay and Desert Creek fields. The results from these wells were disappointing due to poor understanding of the carbonate facies and diagenetic fabrics that create reservoir heterogeneity. These small fields, and similar fields in the basin, are at high risk of premature abandonment. At least 200 million barrels (31.8 million m{sup 3}) of oil will be left behind in these small fields because current development practices leave compartments of the heterogeneous reservoirs undrained. Through proper geological evaluation of the reservoirs, production may be increased by 20 to 50 percent through the drilling of low-cost single or multilateral horizontal legs from existing vertical development wells. In addition, horizontal drilling from existing wells minimizes surface disturbances and costs for field development, particularly in the environmentally sensitive areas of southeastern Utah and southwestern Colorado.

  14. Electric Field Control of the Resistance of Multiferroic Tunnel Junctions with Magnetoelectric Antiferromagnetic Barriers

    Science.gov (United States)

    Merodio, P.; Kalitsov, A.; Chshiev, M.; Velev, J.

    2016-06-01

    Based on model calculations, we predict a magnetoelectric tunneling electroresistance effect in multiferroic tunnel junctions consisting of ferromagnetic electrodes and magnetoelectric antiferromagnetic barriers. Switching of the antiferromagnetic order parameter in the barrier in applied electric field by means of the magnetoelectric coupling leads to a substantial change of the resistance of the junction. The effect is explained in terms of the switching of the orientations of local magnetizations at the barrier interfaces affecting the spin-dependent interface transmission probabilities. Magnetoelectric multiferroic materials with finite ferroelectric polarization exhibit an enhanced resistive change due to polarization-induced spin-dependent screening. These results suggest that devices with active barriers based on single-phase magnetoelectric antiferromagnets represent an alternative nonvolatile memory concept.

  15. Gateable Skyrmion Transport via Field-induced Potential Barrier Modulation

    Science.gov (United States)

    Fook, Hiu Tung; Gan, Wei Liang; Lew, Wen Siang

    2016-02-01

    We report on the influence of pinning potentials on current-driven skyrmion dynamics and demonstrate that skyrmions can be gated via either magnetic or electric fields. When encountering pinning potentials, skyrmions are well known to simply skirt around them. However, we show that skyrmions can be depinned much more easily when their driving force is oriented against the pinning site rather that the intuitive option of being oriented away. This observation can be exploited together with the normally undesirable Magnus force for the creation of a skyrmion diode. The phenomenon is explained by the increased skyrmion compression resulting from the spin transfer torque opposing the repulsive potential. The smaller skyrmion size then experiences a reduced pinning potential. For practical low-power device applications, we show that the same skyrmion compression can be recreated by applying either a magnetic or electric field. Our analysis provides an insight on the skyrmion dynamics and manipulation that is critical for the realization of skyrmion-based transistors and low-power memory.

  16. Transport properties of Dirac electrons in graphene based double velocity-barrier structures in electric and magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Lei [College of Physical Science and Information Engineering, Hebei Advanced Thin Films Laboratory, Hebei Normal University, Shijiazhuang, Hebei 050024 (China); Department of Medical Physics, Basic Medical College, Hebei Medical University, Shijiazhuang, Hebei 050017 (China); Li, Yu-Xian [College of Physical Science and Information Engineering, Hebei Advanced Thin Films Laboratory, Hebei Normal University, Shijiazhuang, Hebei 050024 (China); Liu, Jian-Jun, E-mail: liujj@mail.hebtu.edu.cn [College of Physical Science and Information Engineering, Hebei Advanced Thin Films Laboratory, Hebei Normal University, Shijiazhuang, Hebei 050024 (China); Physics Department, Shijiazhuang University, Shijiazhuang, Hebei 050035 (China)

    2012-10-01

    Using transfer matrix method, transport properties in graphene based double velocity-barrier structures under magnetic and electric fields are numerically studied. It is found that velocity barriers for the velocity ratio (the Fermi velocity inside the barrier to that outside the barrier) less than one (or for the velocity ratio greater than one) have properties similar to electrostatic wells (or barriers). The velocity barriers for the velocity ratio greater than one significantly enlarge the resonant tunneling region of electrostatic barriers. In the presence of magnetic field, the plateau width of the Fano factor with a Poissonian value shortens (or broadens) for the case of the velocity ratio less than one (or greater than one). When the Fermi energy is equal to the electrostatic barrier height, for different values of the velocity ratio, both the conductivities and the Fano factors remain fixed. -- Highlights: ► We model graphene based velocity-barrier structures in electric and magnetic fields. ► Velocity barrier for ξ<1 (ξ>1) have property similar to electrostatic well (barrier). ► Velocity barrier for ξ>1 enlarge the resonant tunneling region of electrostatic barrier. ► The plateau width of Fano factor shortens (or broadens) for the case of ξ<1 (or ξ>1). ► The conductivity remains fixed at the point of E{sub F}=U{sub 0} for different values of ξ.

  17. ON current enhancement of nanowire Schottky barrier tunnel field effect transistors

    Science.gov (United States)

    Takei, Kohei; Hashimoto, Shuichiro; Sun, Jing; Zhang, Xu; Asada, Shuhei; Xu, Taiyu; Matsukawa, Takashi; Masahara, Meishoku; Watanabe, Takanobu

    2016-04-01

    Silicon nanowire Schottky barrier tunnel field effect transistors (NW-SBTFETs) are promising structures for high performance devices. In this study, we fabricated NW-SBTFETs to investigate the effect of nanowire structure on the device characteristics. The NW-SBTFETs were operated with a backgate bias, and the experimental results demonstrate that the ON current density is enhanced by narrowing the width of the nanowire. We confirmed using the Fowler-Nordheim plot that the drain current in the ON state mainly comprises the quantum tunneling component through the Schottky barrier. Comparison with a technology computer aided design (TCAD) simulation revealed that the enhancement is attributed to the electric field concentration at the corners of cross-section of the NW. The study findings suggest an effective approach to securing the ON current by Schottky barrier width modulation.

  18. Determination of tertiary amines based on pH junctions and field amplification in capillary electrophoresis with electrochemiluminescence detection.

    Science.gov (United States)

    Sreedhar, Mallipattu; Lin, Yang-Wei; Tseng, Wei-Lung; Chang, Huan-Tsung

    2005-08-01

    A stacking approach based on pH junction and field amplification has been developed for determining amines by capillary electrophoresis (CE) with electrochemiluminescence (ECL) detection. A two-electrode configuration was employed with an indium/tin oxide-coated glass as a working electrode and a platinum wire as a pseudoreference electrode. The ECL system also contains a flow cell (poly(dimethylsiloxane)-aluminum oxide) that was made from a mixture of Sylgard 184 silicone elastomer, a curing agent, and aluminum oxide. In order to improve the sensitivity of the present CE-ECL system using tris(2,2'-bipyridyl) ruthenium(II) (Ru(bpy)(3) (2+)), a stacking approach based on pH junctions and field amplification has been tested for the analysis of triethylamine (TEA), tripropylamine (TPA), and tributylamine (TBA). Once amines (cations) prepared in citric acid solution (pH < 4.0) migrate towards the background electrolyte (15 mM sodium borate at pH 8.0), they slow down and are stacked at the boundary as a result of deprotonation and decreases in the electric field. By applying hydrodynamic injection of the sample for 60 s, this method provides the concentration limits of detection (signal-to-noise ratio = 3) of 24, 20, and 32 nM for TEA, TPA, and TBA, respectively. The results indicate that the stacking CE-ECL system is better than CE-ECL systems using a two-electrode configuration and comparable to those using a three-electrode configuration. The potential applicability of the new and low-cost CE-ECL system has been demonstrated by the determination of 1.0 microM lidocaine, a local anesthetic drug, in urine without any tedious sample preparation.

  19. Low Schottky Barrier Black Phosphorus Field-Effect Devices with Ferromagnetic Tunnel Contacts

    NARCIS (Netherlands)

    Kamalakar, M Venkata; Madhushankar, B N; Dankert, André; Dash, Saroj P; Bettadahalli Nandishaiah, Madhushankar

    2015-01-01

    Black phosphorus (BP) has been recently unveiled as a promising 2D direct bandgap semiconducting material. Here, ambipolar field-effect transistor behavior of nanolayers of BP with ferromagnetic tunnel contacts is reported. Using TiO2 /Co contacts, a reduced Schottky barrier <50 meV, which can be tu

  20. Modulated heat pulse propagation and partial transport barriers in chaotic magnetic fields

    CERN Document Server

    del-Castillo-Negrete, D

    2016-01-01

    Direct numerical simulations of the time dependent parallel heat transport equation modeling heat pulses driven by power modulation in 3-dimensional chaotic magnetic fields are presented. The numerical method is based on the Fourier formulation of a Lagrangian-Green's function method that provides an accurate and efficient technique for the solution of the parallel heat transport equation in the presence of harmonic power modulation. The numerical results presented provide conclusive evidence that even in the absence of magnetic flux surfaces, chaotic magnetic field configurations with intermediate levels of stochasticity exhibit transport barriers to modulated heat pulse propagation. In particular, high-order islands and remnants of destroyed flux surfaces (Cantori) act as partial barriers that slow down or even stop the propagation of heat waves at places where the magnetic field connection length exhibits a strong gradient. Results on modulated heat pulse propagation in fully stochastic fields and across m...

  1. Sensitive redox speciation of iron, neptunium, and plutonium by capillary electrophoresis hyphenated to inductively coupled plasma sector field mass spectrometry.

    Science.gov (United States)

    Graser, Carl-Heinrich; Banik, Nidhu Lal; Bender, Kerstin Anne; Lagos, Markus; Marquardt, Christian Michael; Marsac, Rémi; Montoya, Vanessa; Geckeis, Horst

    2015-10-01

    The long-term safety assessment for nuclear waste repositories requires a detailed understanding of actinide (geo)chemistry. Advanced analytical tools are required to gain insight into actinide speciation in a given system. The geochemical conditions in the vicinity of a nuclear repository control the redox state of radionuclides, which in turn has a strong impact on their mobility. Besides the long-lived radionuclides plutonium (Pu) and neptunium (Np), which are key elements in high level nuclear waste, iron (Fe) represents a main component in natural systems controlling redox-related geochemical processes. Measuring the oxidation state distribution for redox sensitive radionuclides and other metal ions is challenging at trace concentrations below the detection limit of most available spectroscopic methods (≥10(-6) M). Consequently, ultrasensitive new analytical techniques are required. Capillary electrophoresis (CE) is a suitable separation method for metal cations. CE hyphenated to inductively coupled plasma sector field mass spectrometry (CE-ICP-SF-MS) was used to measure the redox speciation of Pu (III, IV, V, VI), Np (IV, V, VI), and Fe (II, III) at concentrations lower than 10(-7) M. CE coupling and separation parameters such as sample gas pressure, make up flow rate, capillary position, auxiliary gas flow, as well as the electrolyte system were optimized to obtain the maximum sensitivity. We obtain detection limits of 10(-12) M for Np and Pu. The various oxidation state species of Pu and Np in different samples were separated by application of an acetate-based electrolyte system. The separation of Fe (II) and Fe (III) was investigated using different organic complexing ligands, EDTA, and o-phenanthroline. For the Fe redox system, a limit of detection of 10(-8) M was calculated. By applying this analytical system to sorption studies, we were able to underline previously published results for the sorption behavior of Np in highly diluted concentrations, and

  2. Sensitive redox speciation of iron, neptunium, and plutonium by capillary electrophoresis hyphenated to inductively coupled plasma sector field mass spectrometry.

    Science.gov (United States)

    Graser, Carl-Heinrich; Banik, Nidhu Lal; Bender, Kerstin Anne; Lagos, Markus; Marquardt, Christian Michael; Marsac, Rémi; Montoya, Vanessa; Geckeis, Horst

    2015-10-01

    The long-term safety assessment for nuclear waste repositories requires a detailed understanding of actinide (geo)chemistry. Advanced analytical tools are required to gain insight into actinide speciation in a given system. The geochemical conditions in the vicinity of a nuclear repository control the redox state of radionuclides, which in turn has a strong impact on their mobility. Besides the long-lived radionuclides plutonium (Pu) and neptunium (Np), which are key elements in high level nuclear waste, iron (Fe) represents a main component in natural systems controlling redox-related geochemical processes. Measuring the oxidation state distribution for redox sensitive radionuclides and other metal ions is challenging at trace concentrations below the detection limit of most available spectroscopic methods (≥10(-6) M). Consequently, ultrasensitive new analytical techniques are required. Capillary electrophoresis (CE) is a suitable separation method for metal cations. CE hyphenated to inductively coupled plasma sector field mass spectrometry (CE-ICP-SF-MS) was used to measure the redox speciation of Pu (III, IV, V, VI), Np (IV, V, VI), and Fe (II, III) at concentrations lower than 10(-7) M. CE coupling and separation parameters such as sample gas pressure, make up flow rate, capillary position, auxiliary gas flow, as well as the electrolyte system were optimized to obtain the maximum sensitivity. We obtain detection limits of 10(-12) M for Np and Pu. The various oxidation state species of Pu and Np in different samples were separated by application of an acetate-based electrolyte system. The separation of Fe (II) and Fe (III) was investigated using different organic complexing ligands, EDTA, and o-phenanthroline. For the Fe redox system, a limit of detection of 10(-8) M was calculated. By applying this analytical system to sorption studies, we were able to underline previously published results for the sorption behavior of Np in highly diluted concentrations, and

  3. Electron Transport in Graphene-Based Double-Barrier Structure under a Time Periodic Field

    Institute of Scientific and Technical Information of China (English)

    LU Wei-Tao; WANG Shun-Jin

    2011-01-01

    The transport property of electron through graphene-based double-barrier under a time periodic field is investigated. We study the influence of the system parameters and external field strength on the transmission probability.The results show that transmission exhibits various kinds of behavior with the change of parameters due to its angular anisotropy. One could control the values of transmission and conductivity as well as their distribution in each band by tuning the parameters.

  4. Monolayer borophene electrode for effective elimination of both the Schottky barrier and strong electric field effect

    Science.gov (United States)

    Liu, L. Z.; Xiong, S. J.; Wu, X. L.

    2016-08-01

    The formation of Schottky barriers between 2D semiconductors and traditional metallic electrodes has greatly limited the application of 2D semiconductors in nanoelectronic and optoelectronic devices. In this study, metallic borophene was used as a substitute for the traditional noble metal electrode to contact with the 2D semiconductor. Theoretical calculations demonstrated that no Schottky barrier exists in the borophene/2D semiconductor heterostructure. The contact remains ohmic even with a strong electric field applied. This finding provides a way to construct 2D electronic devices and sensors with greatly enhanced performance.

  5. A New Drop Fluidics Enabled by Magnetic Field Mediated Elasto-Capillary Transduction

    CERN Document Server

    Biswas, Saheli; Chaudhury, Manoj K

    2016-01-01

    This research introduces a new drop fluidics, which uses a deformable and stretchable elastomeric film as the platform, instead of the commonly used rigid supports. Such a soft film impregnated with magnetic particles can be modulated with an external electromagnetic field that produces a vast array of topographical landscapes with varying surface curvature, which, in conjunction with capillarity, can direct and control motion of water droplets efficiently and accurately. When a thin layer of oil is present on this film that is deformed locally, a centrosymmetric wedge is formed. A water droplet placed on this oil laden film becomes asymmetrically deformed thus producing a gradient of Laplace pressure within the droplet setting it to motion. A simple theory is presented that accounts for the droplet speed in terms of such geometric variables as the volume of the droplet and the thickness of the oil film covering the soft elastomeric film, as well as such material variables as the viscosity of the oil and inte...

  6. Multidimensionally constrained relativistic mean-field study of triple-humped barriers in actinides

    Science.gov (United States)

    Zhao, Jie; Lu, Bing-Nan; Vretenar, Dario; Zhao, En-Guang; Zhou, Shan-Gui

    2015-01-01

    Background: Potential energy surfaces (PES's) of actinide nuclei are characterized by a two-humped barrier structure. At large deformations beyond the second barrier, the occurrence of a third barrier was predicted by macroscopic-microscopic model calculations in the 1970s, but contradictory results were later reported by a number of studies that used different methods. Purpose: Triple-humped barriers in actinide nuclei are investigated in the framework of covariant density functional theory (CDFT). Methods: Calculations are performed using the multidimensionally constrained relativistic mean field (MDC-RMF) model, with the nonlinear point-coupling functional PC-PK1 and the density-dependent meson exchange functional DD-ME2 in the particle-hole channel. Pairing correlations are treated in the BCS approximation with a separable pairing force of finite range. Results: Two-dimensional PES's of 226,228,230,232Th and 232,235,236,238U are mapped and the third minima on these surfaces are located. Then one-dimensional potential energy curves along the fission path are analyzed in detail and the energies of the second barrier, the third minimum, and the third barrier are determined. The functional DD-ME2 predicts the occurrence of a third barrier in all Th nuclei and 238U . The third minima in 230 ,232Th are very shallow, whereas those in 226 ,228Th and 238U are quite prominent. With the functional PC-PK1 a third barrier is found only in 226 ,228 ,230Th . Single-nucleon levels around the Fermi surface are analyzed in 226Th, and it is found that the formation of the third minimum is mainly due to the Z =90 proton energy gap at β20≈1.5 and β30≈0.7 . Conclusions: The possible occurrence of a third barrier on the PES's of actinide nuclei depends on the effective interaction used in multidimensional CDFT calculations. More pronounced minima are predicted by the DD-ME2 functional, as compared to the functional PC-PK1. The depth of the third well in Th isotopes decreases

  7. Evaporating bubble in a heated capillary: effect of passage on the temperature field of the external wall

    Science.gov (United States)

    Bonnenfant, Jean-François; Benselama, Adel M.; Ayel, Vincent; Bertin, Yves

    2012-11-01

    The nonisothermal Taylor liquid-slug-vapor-bubble problem, occurring inside a capillary of circular cross-section, is investigated numerically. The underlying hydrodynamic and mass transfer phenomena are considered the major heat transfer means in pulsating heat pipes. The temperature signature at the outer side of the capillary, inside which the bubble travels, is particulary examined. It is shown that for typical flow conditions, i.e. for liquid flow velocity and applied heat flux about 0.1 m s-1 and 105 W m-2, respectively, wall thickness effects on capillary wall temperature are negligible in terms of diffusion and lag. In addition, the larger the liquid flow velocity, the more likely the bubble grows (due to evaporation) axially. This investigation opens new avenue to inverse methods where the bubble position is identified only through the temperature profile at the outer side of PHPs channels wall.

  8. Blood-brain barrier permeability in rats exposed to electromagnetic fields used in wireless communication

    OpenAIRE

    Persson, Bertil R.; Leif G Salford; Brun, Arne

    1997-01-01

    iological effects of radio frequency electromagnetic fields (EMF) on the blood-brain barrier (BBB) have been studied in Fischer 344 rats of both sexes. The rats were not anaesthetised during the exposure. All animals were sacrificed by perfusion–fixation of the brains under chloralhydrate anaesthesia after the exposure. The brains were perfused with saline for 3–4 minutes, and thereafter perfusion fixed with 4% formaldehyde for 5–6 minutes. Whole coronal sections of the brains were d...

  9. Field Soil Water Retention of the Prototype Hanford Barrier and Its Variability with Space and Time

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z. F.

    2015-08-14

    Engineered surface barriers are used to isolate underlying contaminants from water, plants, animals, and humans. To understand the flow processes within a barrier and the barrier’s ability to store and release water, the field hydraulic properties of the barrier need to be known. In situ measurement of soil hydraulic properties and their variation over time is challenging because most measurement methods are destructive. A multiyear test of the Prototype Hanford Barrier (PHB) has yielded in situ soil water content and pressure data for a nine-year period. The upper 2 m layer of the PHB is a silt loam. Within this layer, water content and water pressure were monitored at multiple depths at 12 water balance stations using a neutron probe and heat dissipation units. Valid monitoring data from 1995 to 2003 for 4 depths at 12 monitoring stations were used to determine the field water retention of the silt loam layer. The data covered a wide range of wetness, from near saturation to the permanent wilt point, and each retention curve contained 51 to 96 data points. The data were described well with the commonly used van Genuchten water retention model. It was found that the spatial variation of the saturated and residual water content and the pore size distribution parameter were relatively small, while that of the van Genuchten alpha was relatively large. The effects of spatial variability of the retention properties appeared to be larger than the combined effects of added 15% w/w pea gravel and plant roots on the properties. Neither of the primary hydrological processes nor time had a detectible effect on the water retention of the silt loam barrier.

  10. Comparative study of four immortalized human brain capillary endothelial cell lines, hCMEC/D3, hBMEC, TY10, and BB19, and optimization of culture conditions, for an in vitro blood–brain barrier model for drug permeability studies

    OpenAIRE

    Eigenmann, Daniela E; Xue, Gongda; Kwang S Kim; Moses, Ashlee V.; Hamburger, Matthias; Oufir, Mouhssin

    2013-01-01

    Background Reliable human in vitro blood–brain barrier (BBB) models suitable for high-throughput screening are urgently needed in early drug discovery and development for assessing the ability of promising bioactive compounds to overcome the BBB. To establish an improved human in vitro BBB model, we compared four currently available and well characterized immortalized human brain capillary endothelial cell lines, hCMEC/D3, hBMEC, TY10, and BB19, with respect to barrier tightness and paracellu...

  11. Ambipolar ballistic electron emission microscopy studies of gate-field modified Schottky barriers

    Science.gov (United States)

    Che, Y. L.; Pelz, J. P.

    2010-06-01

    Four-terminal ambipolar ballistic electron emission microscopy studies are conducted on Au/Si and Cu/Si Schottky contacts fabricated on back-gated silicon-on-insulator wafers, allowing the electric field to be varied so that both electron (n)- and hole (p)-Schottky barrier heights can be measured at the same sample location. While the individual n- and p-Schottky barrier heights varied by more than 200 meV between the Au/Si and Cu/Si contacts, for a given sample they sum to within 15 meV of the same value, indicating that the individual variations are due to variations in a local surface dipole as compared with tip effects or variations in local composition.

  12. Schottky barrier and contact resistance of InSb nanowire field-effect transistors

    Science.gov (United States)

    Fan, Dingxun; Kang, N.; Gorji Ghalamestani, Sepideh; Dick, Kimberly A.; Xu, H. Q.

    2016-07-01

    Understanding of the electrical contact properties of semiconductor nanowire (NW) field-effect transistors (FETs) plays a crucial role in the use of semiconducting NWs as building blocks for future nanoelectronic devices and in the study of fundamental physics problems. Here, we report on a study of the contact properties of Ti/Au, a widely used contact metal combination, when contacting individual InSb NWs via both two-probe and four-probe transport measurements. We show that a Schottky barrier of height {{{Φ }}}{{SB}}˜ 20 {{meV}} is present at the metal-InSb NW interfaces and its effective height is gate-tunable. The contact resistance ({R}{{c}}) in the InSb NWFETs is also analyzed by magnetotransport measurements at low temperatures. It is found that {R}{{c}} in the on-state exhibits a pronounced magnetic field-dependent feature, namely it is increased strongly with increasing magnetic field after an onset field {B}{{c}}. A qualitative picture that takes into account magnetic depopulation of subbands in the NWs is provided to explain the observation. Our results provide solid experimental evidence for the presence of a Schottky barrier at Ti/Au-InSb NW interfaces and can be used as a basis for design and fabrication of novel InSb NW-based nanoelectronic devices and quantum devices.

  13. Modulated heat pulse propagation and partial transport barriers in chaotic magnetic fields

    Science.gov (United States)

    del-Castillo-Negrete, Diego; Blazevski, Daniel

    2016-04-01

    Direct numerical simulations of the time dependent parallel heat transport equation modeling heat pulses driven by power modulation in three-dimensional chaotic magnetic fields are presented. The numerical method is based on the Fourier formulation of a Lagrangian-Green's function method that provides an accurate and efficient technique for the solution of the parallel heat transport equation in the presence of harmonic power modulation. The numerical results presented provide conclusive evidence that even in the absence of magnetic flux surfaces, chaotic magnetic field configurations with intermediate levels of stochasticity exhibit transport barriers to modulated heat pulse propagation. In particular, high-order islands and remnants of destroyed flux surfaces (Cantori) act as partial barriers that slow down or even stop the propagation of heat waves at places where the magnetic field connection length exhibits a strong gradient. Results on modulated heat pulse propagation in fully stochastic fields and across magnetic islands are also presented. In qualitative agreement with recent experiments in large helical device and DIII-D, it is shown that the elliptic (O) and hyperbolic (X) points of magnetic islands have a direct impact on the spatio-temporal dependence of the amplitude of modulated heat pulses.

  14. Capillary instability of a cylindrical interface of viscous magnetic and nonmagnetic fluids subjected to an axial magnetic field

    CERN Document Server

    Kazhan, V A

    2003-01-01

    In the framework of linearized equations of ferrohydrodynamics, one derives the dispersion equation of the problem on capillary instability of a stationary ferrofluid thread immersed in another ferrofluid of equal density and viscosity. The analytical formulae for the growth rate of a sinusoidal perturbation of a circular cylinder-shaped interface are founded in the limiting cases of large and small Ohnesorge numbers Oh. Numerical calculations carried out under condition Oh>>1 provide insights into the effect of the magnetic force on the capillary break-up of the ferrofluid thread surrounded by a nonmagnetic liquid as well as on the break-up of the nonmagnetic liquid thread being inside the ferrofluid body.

  15. Microcrystallization of a Solution-Processable Organic Semiconductor in Capillaries for High-Performance Ambipolar Field-Effect Transistors.

    Science.gov (United States)

    Watanabe, Satoshi; Fujita, Takuma; Ribierre, Jean-Charles; Takaishi, Kazuto; Muto, Tsuyoshi; Adachi, Chihaya; Uchiyama, Masanobu; Aoyama, Tetsuya; Matsumoto, Mutsuyoshi

    2016-07-13

    We report on the use of microcrystallization in capillaries to fabricate patterned crystalline microstructures of the low-bandgap ambipolar quinoidal quaterthiophene derivative (QQT(CN)4) from a chloroform solution. Aligned needle-shaped QQT(CN)4 crystals were formed in thin film microstructures using either open- or closed- capillaries made of polydimethylsiloxane (PDMS). Their charge transport properties were evaluated in a bottom-gate top-contact transistor configuration. Hole and electron mobilities were found to be as high as 0.17 and 0.083 cm(2) V(-1) s(-1), respectively, approaching the values previously obtained in individual QQT(CN)4 single crystal microneedles. It was possible to control the size of the needle crystals and the microline arrays by adjusting the structure of the PDMS mold and the concentration of QQT(CN)4 solution. These results demonstrate that the microcrystallization in capillaries technique can be used to simultaneously pattern organic needle single crystals and control the microcrystallization processes. Such a simple and versatile method should be promising for the future development of high-performance organic electronic devices. PMID:27150559

  16. Quantum mechanical understanding of field dependence of the apex barrier of a single-wall carbon nanotube

    Science.gov (United States)

    Peng, Jie; Li, Zhibing; He, Chunshan; Deng, Shaozhi; Xu, Ningsheng; Zheng, Xiao; Chen, Guanhua

    2005-12-01

    The potential barrier at the apex of a single-wall carbon nanotube emitter is found to be strongly and nonlinearly dependent on the external applied field, due to a quantum mechanical mechanism instead of the correction of image potential in Fowler-Nordheim theory. The field enhancement factor depends on the applied field and is much smaller than that predicted by the classical theory. The field induced apex-vacuum barrier lowering is confirmed to be the essential mechanism for efficient field electron emission from capped carbon nanotubes.

  17. Dynamic characteristics of double-barrier nanostructures with asymmetric barriers of finite height and widths in a strong ac electric field

    Energy Technology Data Exchange (ETDEWEB)

    Chuenkov, V. A., E-mail: v.a.chuenkov@mail.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2013-12-15

    The theory of the interaction of a monoenergetic flow of injected electrons with a strong high-frequency ac electric field in resonant-tunneling diode (RTD) structures with asymmetric barriers of finite height and width is generalized. In the quasi-classical approximation, electron wavefunctions and tunneling functions in the quantum well and barriers are found. Analytical expressions for polarization currents in RTDs are derived in both the general case and in a number of limiting cases. It is shown that the polarization currents and radiation power in RTDs with asymmetric barriers strongly depend on the ratio of the probabilities of electron tunneling through the emitter and collector barriers. In the quantum mode, when δ = ε − ε{sub r} = ħω ≪ Γ (ε is the energy of electrons injected in the RTD, ħ is Planck’s constant, ω is the ac field frequency, ε{sub r} and Γ are the energy and width of the resonance level, respectively), the active polarization current in a field of E ≈ 2.8ħω/ea (e is the electron charge and a is the quantum-well width) reaches a maximum equal in magnitude to 84% of the direct resonant current, if the probability of electron tunneling through the emitter barrier is much higher than that through the collector barrier. The radiation-generation power at frequencies of ω = 10{sup 12}–10{sup 13} s{sup −1} can reach 10{sup 5}–10{sup 6} W/cm{sup 2} in this case.

  18. Multidimensionally-constrained relativistic mean-field study of triple-humped barriers in actinides

    CERN Document Server

    Zhao, Jie; Vretenar, Dario; Zhao, En-Guang; Zhou, Shan-Gui

    2014-01-01

    Potential energy surfaces (PES's) of actinide nuclei are characterized by a two-humped barrier structure. At large deformations beyond the second barrier, the occurrence of a third one was predicted by macroscopic-microscopic model calculations in the 1970s but contradictory results were later obtained with a number of different models. In this paper, triple-humped barriers in actinide nuclei are investigated with covariant density functional theory (CDFT). Calculations are performed using the multidimensionally-constrained relativistic mean field (MDC-RMF) model, with functionals PC-PK1 and DD-ME2 in the particle-hole channel, while pairing correlations are treated in the BCS approximation with a separable and finite range pairing force. Two-dimensional PES's of $^{226,228,230,232}$Th and $^{232,234,236,238}$U are mapped and the third minima on these surfaces are located. In a second step the one-dimensional potential energy curves along the fission path are analyzed in detail and the energies of the second ...

  19. Novel field-effect schottky barrier transistors based on graphene-MoS 2 heterojunctions

    KAUST Repository

    Tian, He

    2014-08-11

    Recently, two-dimensional materials such as molybdenum disulphide (MoS 2) have been demonstrated to realize field effect transistors (FET) with a large current on-off ratio. However, the carrier mobility in backgate MoS2 FET is rather low (typically 0.5-20 cm2/V.s). Here, we report a novel field-effect Schottky barrier transistors (FESBT) based on graphene-MoS2 heterojunction (GMH), where the characteristics of high mobility from graphene and high on-off ratio from MoS2 are properly balanced in the novel transistors. Large modulation on the device current (on/off ratio of 105) is achieved by adjusting the backgate (through 300 nm SiO2) voltage to modulate the graphene-MoS2 Schottky barrier. Moreover, the field effective mobility of the FESBT is up to 58.7 cm2/V.s. Our theoretical analysis shows that if the thickness of oxide is further reduced, a subthreshold swing (SS) of 40 mV/decade can be maintained within three orders of drain current at room temperature. This provides an opportunity to overcome the limitation of 60 mV/decade for conventional CMOS devices. The FESBT implemented with a high on-off ratio, a relatively high mobility and a low subthreshold promises low-voltage and low-power applications for future electronics.

  20. The patterns of surface capillary-gravity short-crested waves with uniform current fields in coastal waters

    Institute of Scientific and Technical Information of China (English)

    Hu Huang; Jia Fu

    2006-01-01

    A fully three-dimensional surface gravitycapillary short-crested wave system is studied as two progressive wave-trains of equal amplitude and frequency, which are collinear with uniform currents and doubly-periodic in the horizontal plane, are propagating at an angle to each other. The first-and second-order asymptotic analytical solutions of the short-crested wave system are obtained via a perturbation expansion in a small parameter associated with the wave steepness, therefore depicting a series of typical three-dimensional wave patterns involving currents, shallow and deep water, and surface capillary waves, and comparing them with each other.

  1. Effect of the Electron-Phonon Coupling on Barrier D- Quantum Dots in Magnetic Fields

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-Fang

    2002-01-01

    The influence of the electron-phonon coupling on the energy of low-lying states of the barrier D- center,which consists of a positive ion located on the z-axis at a distance from the two-dimensional quantum dot plane and two electrons in the dot plane bound by the ion, is investigated at arbitrary strength of magnetic field by making use of the method of few-body physics. Discontinuous ground-state energy transitions induced by the magnetic field are reported.The dependence of the binding energy of the D- ground state on the quantum dot radius is obtained. A considerable enhancement of the binding is found for the D- ground state, which results from the confinement of electrons and electron-phonon coupling.

  2. Evaluation of properties and thermal stress field for thermal barrier coatings

    Institute of Scientific and Technical Information of China (English)

    王良; 齐红宇; 杨晓光; 李旭

    2008-01-01

    In order to get thermal stress field of the hot section with thermal barrier coating (TBCs), the thermal conductivity and elastic modulus of top-coat are the physical key properties. The porosity of top-coat was tested and evaluated under different high temperatures. The relationship between the microstructure (porosity of top-coat) and properties of TBCs were analyzed to predict the thermal properties of ceramic top-coat, such as thermal conductivity and elastic modulus. The temperature and stress field of the vane with TBCs were simulated using two sets of thermal conductivity data and elastic modulus, which are from literatures and this work, respectively. The results show that the temperature and stress distributions change with thermal conductivity and elastic modulus. The differences of maximum temperatures and stress are 6.5% and 8.0%, respectively.

  3. Field plate engineering for GaN-based Schottky barrier diodes

    Institute of Scientific and Technical Information of China (English)

    Lei Yong; Shi Hongbiao; Lu Hai; Chen Dunjun; Zhang Rong; Zheng Youdou

    2013-01-01

    The practical design of GaN-based Schottky barrier diodes (SBDs) incorporating a field plate (FP)structure necessitates an understanding of their working mechanism and optimization criteria.In this work,the influences of the parameters of FPs upon breakdown of the diode are investigated in detail and the design rules of FP structures for GaN-based SBDs are presented for a wide scale of material and device parameters.By comparing three representative dielectric materials (SiO2,Si3N4 and A12O3) selected for fabricating FPs,it is found that the product of dielectric permittivity and critical field strength of a dielectric material could be used as an index to predict its potential performance for FP applications.

  4. Electric field in an AC dielectric barrier discharge overlapped with a nanosecond pulse discharge

    Science.gov (United States)

    Goldberg, Benjamin M.; Shkurenkov, Ivan; Adamovich, Igor V.; Lempert, Walter R.

    2016-08-01

    The effect of ns discharge pulses on the AC barrier discharge in hydrogen in plane-to-plane geometry is studied using time-resolved measurements of the electric field in the plasma. The AC discharge was operated at a pressure of 300 Torr at frequencies of 500 and 1750 Hz, with ns pulses generated when the AC voltage was near zero. The electric field vector is measured by ps four-wave mixing technique, which generates coherent IR signal proportional to the square of electric field. Absolute calibration was done using an electrostatic (sub-breakdown) field applied to the discharge electrodes, when no plasma was generated. The results are compared with one-dimensional kinetic modeling of the AC discharge and the nanosecond pulse discharge, predicting behavior of both individual micro-discharges and their cumulative effect on the electric field distribution in the electrode gap, using stochastic averaging based on the experimental micro-discharge temporal probability distribution during the AC period. Time evolution of the electric field in the AC discharge without ns pulses, controlled by a superposition of random micro-discharges, exhibits a nearly ‘flat top’ distribution with the maximum near breakdown threshold, reproduced quite well by kinetic modeling. Adding ns pulse discharges on top of the AC voltage waveform changes the AC discharge behavior in a dramatic way, inducing transition from random micro-discharges to a more regular, near-1D discharge. In this case, reproducible volumetric AC breakdown is produced at a well-defined moment after each ns pulse discharge. During the reproducible AC breakdown, the electric field in the plasma exhibits a sudden drop, which coincides in time with a well-defined current pulse. This trend is also predicted by the kinetic model. Analysis of kinetic modeling predictions shows that this effect is caused by large-volume ionization and neutralization of surface charges on the dielectrics by ns discharge pulses. The present

  5. 6H-SiC Schottky barrier source/drain NMOSFET with field-induced source/drain extension

    Institute of Scientific and Technical Information of China (English)

    Tang Xiao-Yan; Zhang Yi-Men; Zhang Yu-Ming; Gao Jin-Xia

    2005-01-01

    A novel SiC Schottky barrier source/drain NMOSFET(SiC SBSD-NMOSFET) with field-induced source/drain(FISD) extension is proposed and demonstrated by numerical simulation for the first time. In the new device the FISD extension is induced by a metal field-plate lying on top of the passivation oxide, and the width of Schottky barrier is controllde by the metal field-plate. The new structure not only eliminates the effect of the significantly improves the on-state current. Moreover, the performance of the present device exhibits very weak dependence on the widths of sidewalls.

  6. Intracellular electric fields produced by dielectric barrier discharge treatment of skin

    International Nuclear Information System (INIS)

    The application of atmospheric pressure plasmas to human tissue has been shown to have therapeutic effects for wound healing and in treatment of skin diseases. These effects are attributed to both production of beneficial radicals which intersect with biological reaction chains and to the surface and intracellular generation of electric fields. In this paper, we report on computational studies of the intersection of plasma streamers in atmospheric pressure dielectric barrier discharges (DBDs) sustained in air with human skin tissue, with emphasis on the intracellular generation of electric fields. Intracellular structures and their electrical properties were incorporated into the computational mesh in order to self-consistently couple gas phase plasma transport with the charging of the surface of the skin and the intracellular production of electrical currents. The short duration of a single plasma filament in DBDs and its intersection with skin enables the intracellular penetration of electric fields. The magnitude of these electric fields can reach 100 kV cm-1 which may exceed the threshold for electroporation.

  7. Intracellular electric fields produced by dielectric barrier discharge treatment of skin

    Science.gov (United States)

    Babaeva, Natalia Yu; Kushner, Mark J.

    2010-05-01

    The application of atmospheric pressure plasmas to human tissue has been shown to have therapeutic effects for wound healing and in treatment of skin diseases. These effects are attributed to both production of beneficial radicals which intersect with biological reaction chains and to the surface and intracellular generation of electric fields. In this paper, we report on computational studies of the intersection of plasma streamers in atmospheric pressure dielectric barrier discharges (DBDs) sustained in air with human skin tissue, with emphasis on the intracellular generation of electric fields. Intracellular structures and their electrical properties were incorporated into the computational mesh in order to self-consistently couple gas phase plasma transport with the charging of the surface of the skin and the intracellular production of electrical currents. The short duration of a single plasma filament in DBDs and its intersection with skin enables the intracellular penetration of electric fields. The magnitude of these electric fields can reach 100 kV cm-1 which may exceed the threshold for electroporation.

  8. Experimental investigation of electron transport across a magnetic field barrier in electropositive and electronegative plasmas

    Science.gov (United States)

    Thomas, M. B.; Rafalskyi, D.; Lafleur, T.; Aanesland, A.

    2016-08-01

    In this paper we experimentally investigate the \\mathbf{E}× \\mathbf{B} drift of electrons in low temperature plasmas containing a magnetic field barrier; a plasma configuration commonly used in gridded negative ion sources. A planar Langmuir probe array is developed to quantify the \\mathbf{E}× \\mathbf{B} drift of electrons over the cross-section of the ion-extraction region of an ion–ion plasma source. The drift is studied as a function of pressure using both electropositive plasmas (Ar), as well electronegative plasmas (Ar and SF6 mixtures), and is demonstrated to result from an interaction of the applied magnetic field and the electric fields in the sheath and pre-sheath near the transverse boundaries. The drift enhances electron transport across the magnetic field by more than two orders of magnitude compared with simple collisional transport, and is found to be strongly dependant on pressure. The lowest pressure resulted in the highest influence of the drift across the extraction area and is found to be 30%.

  9. The long term behaviour of the near-field barrier surrounding a deep underground repository

    International Nuclear Information System (INIS)

    This report describes research to identify the factors which govern or influence the long-term behaviour of the near-field of a nuclear waste repository. The near-field components include the engineered barriers and the natural rock mass although the behaviour of the rock mass is of greater significance over the long-term. The factors which govern the near-field behaviour consist of the processes which operate, and the properties or parameters of the rock mass which might be modified by them. The methods which are available for the prediction of the near-field behaviour have been identified, and the emphasis on computer based methods is noted. Summary details of generic computer techniques are provided for different process modelling requirements. An attempt is made to indicate how different processes will be important at various stages during the life of the repository and how the evaluation of performance assessment process modelling requires input from empirical models and the results of other process predictions. (Author)

  10. Surface Treatment of Polypropylene Films Using Dielectric Barrier Discharge with Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    王长全; 张贵新; 王新新; 陈志宇

    2012-01-01

    Atmospheric pressure non-thermal plasma is of interest for industrial applications. In this study, polypropylene (PP) films are modified by a dielectric barrier discharge (DBD) with a non-uniform magnetic field in air at atmospheric pressure. The surface properties of the PP films before and after a DBD treatment are studied by using contact angle measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The effect of treatment time on the surface modification with and without a magnetic field is investigated. It is found that the hydrophilic improvement depends on the treatment time and magnetic field. It is also found that surface roughness and oxygen-containing groups are introduced onto the PP film surface after the DBD treatment. Surface roughness and oxygen-containing polar functional groups of the PP films increase with the magnetic induction density. The functional groups are identified as C-O, C=O and O-C=O by using XPS analysis. It is concluded that the hydrophilic improvement of PP films treated with a magnetic field is due to a greater surface roughness and more oxygen-containing groups.

  11. Intracellular electric fields produced by dielectric barrier discharge treatment of skin

    Energy Technology Data Exchange (ETDEWEB)

    Babaeva, Natalia Yu; Kushner, Mark J, E-mail: nbabaeva@umich.ed, E-mail: mjkush@umich.ed [University of Michigan, Department of Electrical Engineering and Computer Science, 1301 Beal Ave., Ann Arbor, MI 48109 (United States)

    2010-05-12

    The application of atmospheric pressure plasmas to human tissue has been shown to have therapeutic effects for wound healing and in treatment of skin diseases. These effects are attributed to both production of beneficial radicals which intersect with biological reaction chains and to the surface and intracellular generation of electric fields. In this paper, we report on computational studies of the intersection of plasma streamers in atmospheric pressure dielectric barrier discharges (DBDs) sustained in air with human skin tissue, with emphasis on the intracellular generation of electric fields. Intracellular structures and their electrical properties were incorporated into the computational mesh in order to self-consistently couple gas phase plasma transport with the charging of the surface of the skin and the intracellular production of electrical currents. The short duration of a single plasma filament in DBDs and its intersection with skin enables the intracellular penetration of electric fields. The magnitude of these electric fields can reach 100 kV cm{sup -1} which may exceed the threshold for electroporation.

  12. Field emission spectroscopy evidence for dual-barrier electron tunnelling in nanographite

    Energy Technology Data Exchange (ETDEWEB)

    Bandurin, D. A.; Kleshch, V. I. [Department of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Mingels, S.; Lützenkirchen-Hecht, D.; Müller, G. [FB C Physics Department, University of Wuppertal, 42119 Wuppertal (Germany); Obraztsov, A. N., E-mail: obraz@polly.phys.msu.ru [Department of Physics, M.V. Lomonosov Moscow State University, Moscow 119991 (Russian Federation); Department of Physics and Mathematics, University of Eastern Finland, Joensuu 80101 (Finland)

    2015-06-08

    Nanocarbon films with upstanding flake-like graphite crystallites of nanometre thickness were fabricated by carbon condensation from a methane–hydrogen gas mixture activated by a direct-current discharge. The nanographite (NG) crystallites are composed of a few graphene layers. The adjacent atomic layers are connected partially at the edges of the crystallites to form strongly curved graphene structures. The extraordinary field emission (FE) properties were revealed for the NG films with an average current density of a few mA/cm{sup 2}, reproducibly obtained at a macroscopic applied field of about 1 V/μm. The integral FE current–voltage curves and electron spectra (FEES) of NG cathodes with multiple emitters were measured in a triode configuration. Most remarkably, above a threshold field, two peaks were revealed in FEES with different field-dependent shifts to lower energies. This behaviour evidences electron emission through a dual potential barrier, corresponding to carbon–carbon heterostructure formed as a result of the graphene bending.

  13. Electromechanical Breakdown of Barrier-Type Anodized Aluminum Oxide Thin Films Under High Electric Field Conditions

    Science.gov (United States)

    Chen, Jianwen; Yao, Manwen; Yao, Xi

    2016-02-01

    Barrier-type anodized aluminum oxide (AAO) thin films were formed on a polished aluminum substrate via electrochemical anodization in 0.1 mol/L aqueous solution of ammonium pentaborate. Electromechanical breakdown occurred under high electric field conditions as a result of the accumulation of mechanical stress in the film-substrate system by subjecting it to rapid thermal treatment. Before the breakdown event, the electricity of the films was transported in a highly nonlinear way. Immediately after the breakdown event, dramatic cracking of the films occurred, and the cracks expanded quickly to form a mesh-like dendrite network. The breakdown strength was significantly reduced because of the electromechanical coupling effect, and was only 34% of the self-healing breakdown strength of the AAO film.

  14. A simple drain current model for Schottky-barrier carbon nanotube field effect transistors

    International Nuclear Information System (INIS)

    We report on a new computational model to efficiently simulate carbon nanotube-based field effect transistors (CNT-FET). In the model, a central region is formed by a semiconducting nanotube that acts as the conducting channel, surrounded by a thin oxide layer and a metal gate electrode. At both ends of the semiconducting channel, two semi-infinite metallic reservoirs act as source and drain contacts. The current-voltage characteristics are computed using the Landauer formalism, including the effect of the Schottky barrier physics. The main operational regimes of the CNT-FET are described, including thermionic and tunnel current components, capturing ambipolar conduction, multichannel ballistic transport and electrostatics dominated by the nanotube capacitance. The calculations are successfully compared to results given by more sophisticated methods based on non-equilibrium Green's function formalism (NEGF)

  15. Modeling a Schottky-barrier carbon nanotube field-effect transistor with ferromagnetic contacts

    International Nuclear Information System (INIS)

    In this study, a model of a Schottky-barrier carbon nanotube field-effect transistor (CNT-FET), with ferromagnetic contacts, has been developed. The emphasis is put on analysis of current-voltage characteristics as well as shot (and thermal) noise. The method is based on the tight-binding model and the non-equilibrium Green's function technique. The calculations show that, at room temperature, the shot noise of the CNT-FET is Poissonian in the sub-threshold region, whereas in elevated gate and drain/source voltage regions the Fano factor gets strongly reduced. Moreover, transport properties strongly depend on relative magnetization orientations in the source and drain contacts. In particular, one observes quite a large tunnel magnetoresistance, whose absolute value may exceed 50%

  16. The performance of in situ grown Schottky-barrier single wall carbon nanotube field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhixian [ORNL; Eres, Gyula [ORNL; Jin, Rongying [ORNL; Subedi, Alaska P [ORNL; Mandrus, David [ORNL; Kim, Eugene [ORNL

    2009-01-01

    Electrical transport measurements were used to study device behavior that results from the interplay of defects and inadvertent contact variance that develops in as-grown semiconducting single wall carbon nanotube devices with nominally identical Au contacts. The transport measurements reveal that as-grown nanotubes contain defects that limit the performance of field-effect transistors with ohmic contacts. In Schottky-barrier field-effect transistors the device performance is dominated by the Schottky barrier and the nanotube defects have little effect. We also observed strong rectifying behavior attributed to extreme contact asymmetry due to the different nanoscale roughness of the gold contacts formed during nanotube growth.

  17. The performance of in situ grown Schottky-barrier single wall carbon nanotube field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Zhou Zhixian [Department of Physics and Astronomy, Wayne State University, Detroit, MI 48201 (United States); Eres, Gyula; Jin Rongying; Subedi, Alaska; Mandrus, David [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Kim, Eugene H [Department of Physics, University of Windsor, Windsor, ON, N9B 3P4 (Canada)], E-mail: zxzhou@wayne.edu

    2009-02-25

    Electrical transport measurements were used to study device behavior that results from the interplay of defects and inadvertent contact variance that develops in as-grown semiconducting single wall carbon nanotube devices with nominally identical Au contacts. The transport measurements reveal that as-grown nanotubes contain defects that limit the performance of field-effect transistors with ohmic contacts. In Schottky-barrier field-effect transistors the device performance is dominated by the Schottky barrier and the nanotube defects have little effect. We also observed strong rectifying behavior attributed to extreme contact asymmetry due to the different nanoscale roughness of the gold contacts formed during nanotube growth.

  18. The performance of in situ grown Schottky-barrier single wall carbon nanotube field-effect transistors

    International Nuclear Information System (INIS)

    Electrical transport measurements were used to study device behavior that results from the interplay of defects and inadvertent contact variance that develops in as-grown semiconducting single wall carbon nanotube devices with nominally identical Au contacts. The transport measurements reveal that as-grown nanotubes contain defects that limit the performance of field-effect transistors with ohmic contacts. In Schottky-barrier field-effect transistors the device performance is dominated by the Schottky barrier and the nanotube defects have little effect. We also observed strong rectifying behavior attributed to extreme contact asymmetry due to the different nanoscale roughness of the gold contacts formed during nanotube growth.

  19. Influence of the male ejaculate on post-mating prezygotic barriers in field crickets.

    Directory of Open Access Journals (Sweden)

    Erica L Larson

    Full Text Available Post-copulatory interactions between males and females involve highly coordinated, complex traits that are often rapidly evolving and divergent between species. Failure to produce and deposit eggs may be a common post-mating prezygotic barrier, yet little is known about what prevents the induction of egg-laying between species. The field crickets, Gryllus firmus and G. pennsylvanicus are isolated by a one-way reproductive incompatibility; G. pennsylvanicus males fail to fertilize G. firmus eggs or to induce normal egg-laying in G. firmus females. We use experimental crosses to elucidate the role of accessory gland-derived vs. testis-derived components of the G. firmus male ejaculate on egg-laying in conspecific and heterospecific crosses. Using surgical castrations to create 'spermless' males that transfer only seminal fluid proteins (SFPs we test whether G. firmus male SFPs can induce egg-laying in conspecific crosses and rescue egg-laying in crosses between G. pennsylvanicus males and G. firmus females. We find G. firmus SFPs induce only a small short-term egg-laying response and that SFPs alone cannot explain the normal induction of egg-laying. Gryllus firmus SFPs also do not rescue the heterospecific cross. Testis-derived components, such as sperm or prostaglandins, most likely stimulate egg-laying or act as transporters for SFPs to targets in the female reproductive tract. These results highlight the utility of experimental approaches for investigating the phenotypes that act as barriers between species and suggest that future work on the molecular basis of the one-way incompatibility between G. firmus and G. pennsylvanicus should focus on divergent testis-derived compounds or proteins in addition to SFPs.

  20. Barrier crossing dynamics of a charged particle in the presence of a magnetic field: a new turnover phenomenon.

    Science.gov (United States)

    Baura, Alendu; Sen, Monoj Kumar; Bag, Bidhan Chandra

    2011-05-28

    In this paper we have investigated the effect of a magnetic field on the barrier crossing rate of a charged particle. At the low friction regime we have observed a new turnover phenomenon for the variation of rate as a function of field strength. Thus although the force due to the magnetic field is not dissipative in nature, it plays a role in the steady state barrier crossing rate similar to that of a dissipative force in the weak damping regime. For appreciable damping strength, the rate monotonically decreases with the increase of field strength. We have demonstrated an interesting resonance effect due to the variation of frequency of the harmonic oscillator associated with the y-component motion at low damping and magnetic field strength.

  1. Barrier crossing dynamics of a charged particle in the presence of a magnetic field: a new turnover phenomenon.

    Science.gov (United States)

    Baura, Alendu; Sen, Monoj Kumar; Bag, Bidhan Chandra

    2011-05-28

    In this paper we have investigated the effect of a magnetic field on the barrier crossing rate of a charged particle. At the low friction regime we have observed a new turnover phenomenon for the variation of rate as a function of field strength. Thus although the force due to the magnetic field is not dissipative in nature, it plays a role in the steady state barrier crossing rate similar to that of a dissipative force in the weak damping regime. For appreciable damping strength, the rate monotonically decreases with the increase of field strength. We have demonstrated an interesting resonance effect due to the variation of frequency of the harmonic oscillator associated with the y-component motion at low damping and magnetic field strength. PMID:21483929

  2. Cryogenic Capillary Screen Heat Entrapment

    Science.gov (United States)

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

    2007-01-01

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

  3. Analysis of urinary neurotransmitters by capillary electrophoresis: Sensitivity enhancement using field-amplified sample injection and molecular imprinted polymer solid phase extraction

    Energy Technology Data Exchange (ETDEWEB)

    Claude, Berengere, E-mail: berengere.claude@univ-orleans.fr [Institut de Chimie Organique et Analytique, CNRS FR 2708 UMR 6005, Universite d' Orleans, 45067 Orleans (France); Nehme, Reine; Morin, Philippe [Institut de Chimie Organique et Analytique, CNRS FR 2708 UMR 6005, Universite d' Orleans, 45067 Orleans (France)

    2011-08-12

    Highlights: {yields} Field-amplified sample injection (FASI) improves the sensitivity of capillary electrophoresis through the online pre-concentration samples. {yields} The cationic analytes are stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. {yields} The limits of quantification are 500 times lower than those obtained with hydrodynamic injection. {yields} The presence of salts in the matrix greatly reduces the sensitivity of the FASI/CE-UV method. - Abstract: Capillary electrophoresis (CE) has been investigated for the analysis of some neurotransmitters, dopamine (DA), 3-methoxytyramine (3-MT) and serotonin (5-hydroxytryptamine, 5-HT) at nanomolar concentrations in urine. Field-amplified sample injection (FASI) has been used to improve the sensitivity through the online pre-concentration samples. The cationic analytes were stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. Several FASI parameters have been optimized (ionic strength of the running buffer, concentration of the sample protonation agent, composition of the sample solvent and nature of the pre-injection plug). Best results were obtained using H{sub 3}PO{sub 4}-LiOH (pH 4, ionic strength of 80 mmol L{sup -1}) as running buffer, 100 {mu}mol L{sup -1} of H{sub 3}PO{sub 4} in methanol-water 90/10 (v/v) as sample solvent and 100 {mu}mol L{sup -1} of H{sub 3}PO{sub 4} in water for the pre-injection plug. In these conditions, the linearity was verified in the 50-300 nmol L{sup -1} concentration range for DA, 3-MT and 5-HT with a determination coefficient (r{sup 2}) higher than 0.99. The limits of quantification (10 nmol L{sup -1} for DA and 3-MT, 5.9 nmol L{sup -1} for 5-HT) were 500 times lower than those obtained with hydrodynamic injection. However, if this method is applied to the analysis of

  4. Analysis of urinary neurotransmitters by capillary electrophoresis: Sensitivity enhancement using field-amplified sample injection and molecular imprinted polymer solid phase extraction

    International Nuclear Information System (INIS)

    Highlights: → Field-amplified sample injection (FASI) improves the sensitivity of capillary electrophoresis through the online pre-concentration samples. → The cationic analytes are stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. → The limits of quantification are 500 times lower than those obtained with hydrodynamic injection. → The presence of salts in the matrix greatly reduces the sensitivity of the FASI/CE-UV method. - Abstract: Capillary electrophoresis (CE) has been investigated for the analysis of some neurotransmitters, dopamine (DA), 3-methoxytyramine (3-MT) and serotonin (5-hydroxytryptamine, 5-HT) at nanomolar concentrations in urine. Field-amplified sample injection (FASI) has been used to improve the sensitivity through the online pre-concentration samples. The cationic analytes were stacked at the capillary inlet between a zone of low conductivity - sample and pre-injection plug - and a zone of high conductivity - running buffer. Several FASI parameters have been optimized (ionic strength of the running buffer, concentration of the sample protonation agent, composition of the sample solvent and nature of the pre-injection plug). Best results were obtained using H3PO4-LiOH (pH 4, ionic strength of 80 mmol L-1) as running buffer, 100 μmol L-1 of H3PO4 in methanol-water 90/10 (v/v) as sample solvent and 100 μmol L-1 of H3PO4 in water for the pre-injection plug. In these conditions, the linearity was verified in the 50-300 nmol L-1 concentration range for DA, 3-MT and 5-HT with a determination coefficient (r2) higher than 0.99. The limits of quantification (10 nmol L-1 for DA and 3-MT, 5.9 nmol L-1 for 5-HT) were 500 times lower than those obtained with hydrodynamic injection. However, if this method is applied to the analysis of neurotransmitters in urine, the presence of salts in the matrix greatly reduces the sensitivity of the FASI

  5. Multidimensionally-constrained relativistic mean-field study of triple-humped barriers in actinides

    OpenAIRE

    Zhao, Jie; Lu, Bingnan; Vretenar, Dario; Zhao, En-Guang; Zhou, Shan-Gui

    2014-01-01

    Potential energy surfaces (PES's) of actinide nuclei are characterized by a two-humped barrier structure. At large deformations beyond the second barrier the occurrence of a third one was predicted by Mic-Mac model calculations in the 1970s, but contradictory results were later reported. In this paper, triple-humped barriers in actinide nuclei are investigated with covariant density functional theory (CDFT). Calculations are performed using the multidimensionally-constrained relativistic mean...

  6. Barrier Island Ecology: A Professional Development Activity for Faculty and Staff of Calhoun Community College. Field Trip Reference Booklet.

    Science.gov (United States)

    Collier, Don; And Others

    As part of the Professional Development Workshop at Calhoun Community College, the Department of Natural Sciences conducted the third annual Spring Wilderness Pilgrimage in March 1989, a week-long environmental awareness field trip for faculty and staff. Designed as a study of the plants and animals on a barrier island off the coast of Florida,…

  7. Quasi-stationary states of electrons interacting with strong electromagnetic field in two-barrier resonance tunnel nano-structure

    OpenAIRE

    M.V. Tkach; Ju.O. Seti; O.M. Voitsekhivska

    2012-01-01

    An exact solution of non-stationary Schrodinger equation is obtained for a one-dimensional movement of electrons in an electromagnetic field with arbitrary intensity and frequency. Using it, the permeability coefficient is calculated for a two-barrier resonance tunnel nano-structure placed into a high-frequency electromagnetic field. It is shown that a nano-structure contains quasi-stationary states the spectrum of which consists of the main and satellite energies. The properties of resonance...

  8. Numerical simulation of the sound reflection effects of noise barriers in near and far field

    NARCIS (Netherlands)

    Lutgendorf, D.; Roo, F. de; Eerden, F.J.M. van der; Jean, P.; Ecotière, D.; Dutilleux, G.

    2011-01-01

    This paper deals with the first stages of the development of a new test method for evaluating the reflectivity performance of noise barriers. The reflectivity performance describes the increase in sound level at a receiver due to the presence of the noise barrier. First the current test method for s

  9. The attenuation of oscillatory thermo-capillary convection in the oxide melt by a transverse magnetic field

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of a transverse magnetic field on the oscillatory thermocapillary con- vection in the NaBi(WO4)2 melt was studied by using the in-situ observation system. The oscillation was attenuated when the 60 mT magnetic field was applied, as shown by the decrease in the amplitude and the frequency. Furthermore, the os- cillation under smaller temperature difference was stabilized after the magnetic field was applied. The magnetic effect could be due to the Lorentz force generated by the interaction between motional ions and the vertical magnetic field. The ionic conductivities were measured to demonstrate the effect of the magnetic field. The solid ionic electrical conductivity increases with the temperature rise, and the melt ionic electrical conductivity was measured to be about 2.0×10-4 -1cm-1. Experi- mental results manifest that the effect of the magnetic field on anions and cations in the melt makes the flow change to the direction normal to the applied field, so the flow is more orderly and the oscillation is suppressed.

  10. Dissipated power and induced velocity fields data of a micro single dielectric barrier discharge plasma actuator for active flow control☆

    Science.gov (United States)

    Pescini, E.; Martínez, D.S.; De Giorgi, M.G.; Francioso, L.; Ficarella, A.

    2015-01-01

    In recent years, single dielectric barrier discharge (SDBD) plasma actuators have gained great interest among all the active flow control devices typically employed in aerospace and turbomachinery applications [1,2]. Compared with the macro SDBDs, the micro single dielectric barrier discharge (MSDBD) actuators showed a higher efficiency in conversion of input electrical power to delivered mechanical power [3,4]. This article provides data regarding the performances of a MSDBD plasma actuator [5,6]. The power dissipation values [5] and the experimental and numerical induced velocity fields [6] are provided. The present data support and enrich the research article entitled “Optimization of micro single dielectric barrier discharge plasma actuator models based on experimental velocity and body force fields” by Pescini et al. [6]. PMID:26425667

  11. From microscopic to macroscopic dynamics in mean-field theory: effect of neutron skin on fusion barrier and dissipation

    Energy Technology Data Exchange (ETDEWEB)

    Lacroix, D

    2001-07-01

    In this work, we introduce a method to reduce the microscopic mean-field theory to a classical macroscopic dynamics at the initial stage of fusion reaction. We show that TDHF (Time-dependent Hartree-Fock) could be a useful tool to infer information on the fusion barrier as well as on one-body dissipation effect. We apply the reduction of information to the case of head-on reaction between a {sup 16}O and {sup 16,22,24,28}O in order to quantify the effect of neutron skin on fusion. We show that the precise determination of fusion barrier requires, in addition to the relative distance between center of mass, the introduction of an additional collective coordinate that explicitly breaks the neutron-proton symmetry. With this additional collective variable, we obtain a rather precise determination of the barrier position, height and diffuseness as well as one-body friction. (author)

  12. High-frequency capillary waves excited by oscillating microbubbles

    CERN Document Server

    Pommella, Angelo; Poulichet, Vincent; Garbin, Valeria

    2013-01-01

    This fluid dynamics video shows high-frequency capillary waves excited by the volumetric oscillations of microbubbles near a free surface. The frequency of the capillary waves is controlled by the oscillation frequency of the microbubbles, which are driven by an ultrasound field. Radial capillary waves produced by single bubbles and interference patterns generated by the superposition of capillary waves from multiple bubbles are shown.

  13. Field study of gravel admix, vegetation, and soil water interactions: Protective Barrier Program Status Reprt - FY 1989

    Energy Technology Data Exchange (ETDEWEB)

    Waugh, W.J.; Thiede, M.E.; Kemp, C.J.; Cadwell, L.L. Link, S.O.

    1990-08-01

    Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company (Westinghouse Hanford) are collaborating on a field study of the effects of gravel admixtures on plant growth and soil water storage in protective barriers. Protective barriers are engineered earthern covers designed to prevent water, plants, and animals from contacting buried waste and transporting contaminants to groundwater or the land surface. Some of the proposed designs include gravel admixtures or gravel mulches on the barrier surface to control soil loss by wind and runoff. The purpose of this study is to measure, in a field setting, the influence of surface gravel additions on soil water storage and plant cover. The study plots are located northwest of the Yakima Gate in the McGee Ranch old field. Here we report the status of work completed in FY 1989 on the creation of a data management system, a test of water application uniformity, field calibration of neutron moisture gages, and an analysis of the response of plants to various combinations of gravel admixtures and increased rainfall. 23 refs., 11 figs., 6 tabs.

  14. Above-well, Stark, and potential-barrier resonances of an open square well in a static external electric field

    CERN Document Server

    Emmanouilidou, A

    2004-01-01

    Besides the well known Stark resonances, which are localized in the potential well and tunnel through the potential barrier created by the dc-field, "strange" long and short-lived resonances are analytically obtained. These resonances are not localized inside the potential well. We show that the narrow ones are localized above the potential well. These narrow resonances give rise to a {\\it peak structure} in a 1D scattering experiment. We also show that the broad overlapping resonances are associated with the static electric field potential barrier. These "strange" overlapping resonances do not give rise to a {\\it peak structure} in a 1D scattering experiment. We propose a 2D experimental set-up where in principle these short-lived states should be observed as {\\it peaks}. Broad overlapping resonances, associated only with the static electric field potential barrier, could also have observable effects in a $N>1$ array of quantum wells in the presence of a truncated static electric field. This last problem is ...

  15. Three-step stacking by field-enhanced sample injection, sweeping, and micelle to solvent stacking in capillary electrophoresis: Anionic analytes.

    Science.gov (United States)

    Grochocki, Wojciech; Markuszewski, Michał J; Quirino, Joselito P

    2016-04-15

    Three-step stacking by field-enhanced sample injection (FESI), sweeping, and micelle to solvent stacking (MSS) in co-EOF capillary zone electrophoresis (CZE) is presented for anionic analytes. Long FESI produced an overloaded stacked zone of analytes (four model penicillins). Sweeping of the FESI zone was by electrokinetic injection of cetyltrimethylammonium bromide (CTAB) micelles. MSS was by short injection of 60% methanol that released the swept analytes from CTAB micelles. The sensitivity enhancement factors were 146-279 and 519-954 for conductivity ratio of 10 and 100, respectively. The SEF enhancement factors (factor=SEF from three-step stacking/SEF from FESI) were 16-32 and 6-10, correspondingly. The LODs were between 6.6-13.2 ng/mL, repeatability (intraday and interday) was %RSD≤5.4%, and linearity was R(2)≥0.998. Application to real sample was investigated using fortified plasma after liquid-liquid extraction. PMID:27000740

  16. Injectable barriers for waste isolation

    International Nuclear Information System (INIS)

    In this paper the authors report laboratory work and numerical simulation done in support of development and demonstration of injectable barriers formed from either of two fluids: colloidal silica or polysiloxane. Two principal problems addressed here are control of gel time and control of plume emplacement in the vadose zone. Gel time must be controlled so that the viscosity of the barrier fluid remains low long enough to inject the barrier, but increases soon enough to gel the barrier in place. During injection, the viscosity must be low enough to avoid high injection pressures which could uplift or fracture the formation. To test the grout gel time in the soil, the injection pressure was monitored as grouts were injected into sandpacks. When grout is injected into the vadose zone, it slumps under the influence of gravity, and redistributes due to capillary forces as it gels. The authors have developed a new module for the reservoir simulator TOUGH2 to model grout injection into the vadose zone, taking into account the increase of liquid viscosity as a function of gel concentration and time. They have also developed a model to calculate soil properties after complete solidification of the grout. The numerical model has been used to design and analyze laboratory experiments and field pilot tests. The authors present the results of computer simulations of grout injection, redistribution, and solidification

  17. Injectable barriers for waste isolation

    Energy Technology Data Exchange (ETDEWEB)

    Persoff, P.; Finsterle, S.; Moridis, G.J.; Apps, J.; Pruess, K. [Lawrence Berkeley National Lab., CA (United States). Earth Sciences Div.; Muller, S.J. [Univ. of California, Berkeley, CA (United States). Dept. of Chemical Engineering

    1995-03-01

    In this paper the authors report laboratory work and numerical simulation done in support of development and demonstration of injectable barriers formed from either of two fluids: colloidal silica or polysiloxane. Two principal problems addressed here are control of gel time and control of plume emplacement in the vadose zone. Gel time must be controlled so that the viscosity of the barrier fluid remains low long enough to inject the barrier, but increases soon enough to gel the barrier in place. During injection, the viscosity must be low enough to avoid high injection pressures which could uplift or fracture the formation. To test the grout gel time in the soil, the injection pressure was monitored as grouts were injected into sandpacks. When grout is injected into the vadose zone, it slumps under the influence of gravity, and redistributes due to capillary forces as it gels. The authors have developed a new module for the reservoir simulator TOUGH2 to model grout injection into the vadose zone, taking into account the increase of liquid viscosity as a function of gel concentration and time. They have also developed a model to calculate soil properties after complete solidification of the grout. The numerical model has been used to design and analyze laboratory experiments and field pilot tests. The authors present the results of computer simulations of grout injection, redistribution, and solidification.

  18. The penetration barrier of water through graphynes' pores: first-principles predictions and force field optimization

    CERN Document Server

    Bartolomei, Massimiliano; Hernández, Marta I; Campos-Martínez, José; Pirani, Fernando; Giorgi, Giacomo; Yamashita, Koichi

    2013-01-01

    Graphynes are novel two-dimensional carbon-based materials that -due to their nanoweb-like structure- have been proposed as molecular filters, especially for water purification technologies. In this work we carry out first principles electronic structure calculations at the MP2C level of theory to assess the interaction between water and graphyne, graphdiyne and graphtriyne pores. The computed penetration barriers suggest that water transport is unfeasible through graphyne while being unimpeded for graphtriyne. Nevertheless, for graphdiyne, which presents a pore size almost matching that of water, a low barrier is found which in turn disappears if an active hydrogen bond with an additional water molecule on the opposite side of the opening is taken into account. These results support the possibility of using graphtriyne as an efficient membrane for water filtration but, in contrast with previous determinations, they do not exclude graphdiyne. In fact, the related first principles penetration barrier leads to ...

  19. Optimal Magnetic Field for Crossing Super-Para-Magnetic Nanoparticles through the Brain Blood Barrier: A Computational Approach

    Directory of Open Access Journals (Sweden)

    Maysam Z. Pedram

    2016-06-01

    Full Text Available This paper scrutinizes the magnetic field effect to deliver the superparamagnetic nanoparticles (SPMNs through the Blood Brain Barrier (BBB. Herein we study the interaction between the nanoparticle (NP and BBB membrane using Molecular Dynamic (MD techniques. The MD model is used to enhance our understanding of the dynamic behavior of SPMNs crossing the endothelial cells in the presence of a gradient magnetic field. Actuation of NPs under weak magnetic field offers the great advantage of a non-invasive drug delivery without the risk of causing injury to the brain. Furthermore, a weak magnetic portable stimulator can be developed using low complexity prototyping techniques. Based on MD simulation results in this paper, SPMNs can cross the cell membrane while experiencing very weak mechanical forces in the range of pN. This study also derives guidelines for the design of the SPMNs dedicated to crossing the BBB using external magnetic fields.

  20. Impacts on oil recovery from capillary pressure and capillary heterogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Bognoe, Thomas

    2008-07-01

    The main conclusions drawn from this thesis are; 7 scientific papers are published on a broad variety of subjects, and describes in detail the experiments and research treated in this thesis. Scientific research has been performed, investigating the subjects of capillary pressure and capillary heterogeneities from different angles. This thesis discusses the findings in this study and aims to illustrate the benefits of the results obtained for further development of other experiments, and/or even the industrial benefits in field development. The methods for wettability alteration have developed throughout the work. From producing heterogeneous wettability alterations, the methods have improved to giving both radial and lateral uniform wettability alterations, which also remains unaltered throughout the duration of the experimental work. The alteration of wettability is dependent on initial water saturation, flow rate, aging time and crude oil composition. Capillary pressure and relative permeability curves have been measured for core plugs at different wettabilities using conventional centrifuge methods. The trends observed are mostly consistent with theory. The production mechanisms of strongly and moderately water wet chalk has been investigated. At strongly water wet conditions in fractured chalk; the flow is governed by capillary forces, showing strong impact from the fractures. At moderately water wet conditions, the impact of the fractures are absent, and a dispersed water front is observed during the displacement. The oil recovery is about the same, at the two wettabilities. Fracture crossing mechanisms at the same wettability conditions have been mapped. And the observations are consistent with those of the water floods. During strongly water wet displacement, the fracture crossing is occurring once the inlet core has reached endpoint of spontaneous imbibition. At moderately water wet conditions the fracture crossing is less abrupt, and creation of wetting

  1. Falcon series data report: 1987 LNG vapor barrier verification field trials

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.C.; Cederwall, R.T.; Chan, S.T.; Ermak, D.L.; Koopman, R.P.; Lamson, K.C.; McClure, J.W.; Morris, L.K.

    1990-06-01

    A series of five Liquefied Natural Gas Spills up to 66 m{sup 3} in volume were performed on water within a vapor barrier structure at Frenchman Flat on the Nevada Test Site as a part of a joint government/industry study. This data report presents a description of the tests, the test apparatus, the instrumentation, the meteorological conditions, and the data from the tests. 16 refs., 27 figs., 8 tabs.

  2. Model test of a capillary barrier evapotranspiration cover for landfills%垃圾填埋场毛细阻滞型腾发封顶模型试验

    Institute of Scientific and Technical Information of China (English)

    张文杰; 林午; 董林兵

    2014-01-01

    作为替代型垃圾填埋场封顶,毛细阻滞型腾发封顶具有诸多优点,但目前主要在欧美干旱、半干旱地区使用,对其在湿润气候区工作性能的研究较少。选用低塑性粉质黏土和砾砂作为填料,在杭州市一露天环境构筑模型土柱并培育植被,量测自然降雨、蒸发和植被蒸腾作用下土柱透水量、地表径流量和各深度含水率变化,探讨毛细阻滞型腾发封顶的工作机制。试验历时15个月,得到该封顶在降雨高峰期、晴热高温期、台风影响期和冬季阴冷期等时段的响应。试验结果表明,降雨和腾发作用下粉质黏土含水率变化较大,底部砾砂中也有较小幅度干湿循环,腾发可在整个封顶土层范围内起作用;当粉质黏土底部达到饱和,砾砂含水率接近4%时底部有水透出,此时该封顶暂时失效,后随水汽运移毛细阻滞界面功能恢复,该封顶仍能正常工作;试验过程中,降雨总量为1782.6 mm,共产生地表径流为53.08 mm,透水为19.64 mm,其他降水均在土层吸持与腾发交替作用下最终返回大气,在试验期间该封顶能有效地阻止降雨入渗。%Capillary barrier evapotranspiration covers have many advantages over conventional covers. But they are mainly used in arid or semi-arid areas in USA and Europe. Whether they can be used in humid areas remains to be determined. Using low plastic silty clay and gravelly sand as material, a soil column is constructed in outdoor environment in Hangzhou and vegetation is planted. Water content, percolation and surface runoff are measured. Peak rainfall season, sunny and hot season, typhoon period and winter season are experienced during the monitoring 15 months. Results show that volumetric water content of silty clay changes greatly under natural infiltration and evapotranspiration; the and small dry-wet cycles exist in gravelly sand. It is shown that evapotranspiration acts

  3. Intramedullary capillary haemangioma.

    LENUS (Irish Health Repository)

    Kelleher, T

    2012-02-03

    Intramedullary capillary haemangioma is extremely rare and only four cases have been previously reported. We describe a further case, outlining the clinical, radiological, surgical and pathological features.

  4. Capillary bridges in electric fields

    NARCIS (Netherlands)

    Klingner, Anke; Buehrle, Juergen; Mugele, Frieder

    2004-01-01

    We analyzed the morphology of droplets of conductive liquids placed between two parallel plate electrodes as a function of the two control parameters electrode separation and applied voltage. Both electrodes were covered by thin insulating layers, as in conventional electrowetting experiments. Depen

  5. Towards a better understanding of dielectric barrier discharges in ferroelectrets: Paschen breakdown fields in micrometer sized voids

    Science.gov (United States)

    Harris, Scott; Mellinger, Axel

    2014-04-01

    Charged cellular polypropylene foams (i.e., ferro- or piezoelectrets) demonstrate high piezoelectric activity upon being electrically charged. When an external electric field is applied, dielectric barrier discharges (DBDs) occur, resulting in a separation of charges which are subsequently deposited on dielectric surfaces of internal micrometer sized voids. This deposited space charge is responsible for the piezoelectric activity of the material. Previous studies have indicated charging fields larger than predicted by Townsend's model of Paschen breakdown applied to a multilayered electromechanical model; a discrepancy which prompted the present study. The actual breakdown fields for micrometer sized voids were determined by constructing single cell voids using polypropylene spacers with heights ranging from 8 to 75 μm, "sandwiched" between two polypropylene dielectric barriers and glass slides with semi-transparent electrodes. Subsequently, a bipolar triangular charging waveform with a peak voltage of 6 kV was applied to the samples. The breakdown fields were determined by monitoring the emission of light due to the onset of DBDs using an electron multiplying CCD camera. The breakdown fields at absolute pressures from 101 to 251 kPa were found to be in good agreement with the standard Paschen curves. Additionally, the magnitude of the light emission was found to scale linearly with the amount of gas, i.e., the height of the voids. Emissions were homogeneous over the observed regions of the voids for voids with heights of 25 μm or less and increasingly inhomogeneous for void heights greater than 40 μm at high electric fields.

  6. Vanishing magnetic shear and electron transport barriers in the RFX-mod reversed field pinch.

    Science.gov (United States)

    Gobbin, M; Bonfiglio, D; Escande, D F; Fassina, A; Marrelli, L; Alfier, A; Martines, E; Momo, B; Terranova, D

    2011-01-14

    We define the safety factor q for the helical plasmas of the experiment RFX-mod by accounting for the actual three-dimensional nature of the magnetic flux surfaces. Such a profile is not monotonic but goes through a maximum located in the vicinity of the electron transport barriers measured by a high resolution Thomson scattering diagnostic. Helical states with a single axis obtained in viscoresistive magnetohydrodynamic numerical simulations exhibit similar nonmonotonic q profiles provided that the final states are preceded by a magnetic island phase, like in the experiment.

  7. DNA Sequencing Using capillary Electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Barry Karger

    2011-05-09

    application papers of sequencing up to this level were also published in the mid 1990's. A major interest of the sequencing community has always been read length. The longer the sequence read per run the more efficient the process as well as the ability to read repeat sequences. We therefore devoted a great deal of time to studying the factors influencing read length in capillary electrophoresis, including polymer type and molecule weight, capillary column temperature, applied electric field, etc. In our initial optimization, we were able to demonstrate, for the first time, the sequencing of over 1000 bases with 90% accuracy. The run required 80 minutes for separation. Sequencing of 1000 bases per column was next demonstrated on a multiple capillary instrument. Our studies revealed that linear polyacrylamide produced the longest read lengths because the hydrophilic single strand DNA had minimal interaction with the very hydrophilic linear polyacrylamide. Any interaction of the DNA with the polymer would lead to broader peaks and lower read length. Another important parameter was the molecular weight of the linear chains. High molecular weight (> 1 MDA) was important to allow the long single strand DNA to reptate through the entangled polymer matrix. In an important paper, we showed an inverse emulsion method to prepare reproducibility linear polyacrylamide polymer with an average MWT of 9MDa. This approach was used in the polymer for sequencing the human genome. Another critical factor in the successful use of capillary electrophoresis for sequencing was the sample preparation method. In the Sanger sequencing reaction, high concentration of salts and dideoxynucleotide remained. Since the sample was introduced to the capillary column by electrokinetic injection, these salt ions would be favorably injected into the column over the sequencing fragments, thus reducing the signal for longer fragments and hence reading read length. In two papers, we examined the role of

  8. Magnetic field stimulated enhancement of the barrier for vortex penetration in bended bridges of thin TaN films

    Energy Technology Data Exchange (ETDEWEB)

    Ilin, Konstantin, E-mail: konstantin.ilin@kit.edu; Siegel, Michael, E-mail: michael.siegel@kit.edu

    2014-08-15

    Highlights: • Critical state in mesoscopic superconducting TaN structures has been studied. • Suppression of the current crowding by magnetic field has been investigated. • Maximum of critical current of bended TaN bridges is at non-zero magnetic field. • The critical current of 90° bended bridges increases by 37% in magnetic field. • Significant bulk pinning is in ultra-thin TaN mesoscopic structures. - Abstract: An increase of the supercurrent density in the vicinity of sharp bends of mesoscopic superconducting strips (the current crowding) leads to a decrease of the potential barrier for vortex penetration and thus to a decrease of the measured critical current I{sub C} of the strip in comparison to the de-pairing critical current. However, it has been shown that the Meissner currents induced by an external magnetic field of appropriate direction reduce the effect of current crowding resulting in an increase of the measured I{sub C} of superconducting mesoscopic structures with bends. We performed a detailed experimental investigation of the dependence of critical current on magnetic field in straight and bended bridges made from thin TaN films. Indeed, in the case of bridges with bends, the critical current reaches a maximum at non-zero magnetic fields which value increases with an increase of the angle of bends.

  9. Experimental research on electric field jump in low magnetic fields: Detection of damage in new ex-situ MgB{sub 2} barriers in MgB{sub 2} wires

    Energy Technology Data Exchange (ETDEWEB)

    Gajda, D., E-mail: dangajda@op.pl [International Laboratory of High Magnetic Fields and Low Temperatures, Gajowicka 95, 53-421 Wroclaw (Poland); Morawski, A. [Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warszawa (Poland); Zaleski, A. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422 Wroclaw (Poland); Hossain, M.S.A. [Institute for Superconducting and Electronic Materials, AIIM, University of Wollongong, North Wollongong, NSW 2519 (Australia); Rindfleisch, M. [Hyper Tech Research, Inc, 1275 Kinnear Road, Columbus, OH 43212 (United States); Cetner, T. [Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warszawa (Poland)

    2015-10-25

    We explored the incorporation of field sweep (constant current and rapidly increasing magnetic field) into the four-probe method as a new technique to detect defects in barrier layers in superconducting MgB{sub 2} wires. This method allows us to observe jumps in the electric field in low magnetic fields. The scanning electron microscopy results indicate that such a jump originates from cracks in Nb barriers and ex-situ MgB{sub 2} barriers. Our research indicates that the field sweep allows us to detect damage to barriers that are made of superconducting materials. This method can be the basis for an industrial method for detecting damages in MgB{sub 2} wires. These defects reduce the critical current of MgB{sub 2} wire. Detection and removal of these defects will allow us to produce MgB{sub 2} wires with ex-situ MgB{sub 2} and Nb barriers that will have improved critical current density. Manufacturing of MgB{sub 2} wires with new ex-situ MgB{sub 2} barriers is a new technological concept. This type of barrier is cheaper and easier to manufacture, leading to cheaper MgB{sub 2} wires. Moreover, we show that critical current can be measured by two methods: current sweep (constant magnetic field and quickly increasing current) and field sweep. - Graphical abstract: Our results indicate that the jump electric field low magnetic fields. This jump indicates damage in Nb and ex situ MgB{sub 2} barrier. Detection and removal of defects will increase J{sub c} in MgB{sub 2} wires and will increase the applicability of MgB{sub 2} wire. - Highlights: • Jump electric field in the 1 T indicates damage to the Nb barrier. • Jump resistance at 9 K indicates damage to the Nb barrier. • Jump electric field in low magnetic field indicates damage to ex situ MgB{sub 2} barrier. • Damage Nb and ex situ MgB{sub 2} barrier significantly reduces the critical current density in the MgB{sub 2} wire.

  10. Experimental research on electric field jump in low magnetic fields: Detection of damage in new ex-situ MgB2 barriers in MgB2 wires

    International Nuclear Information System (INIS)

    We explored the incorporation of field sweep (constant current and rapidly increasing magnetic field) into the four-probe method as a new technique to detect defects in barrier layers in superconducting MgB2 wires. This method allows us to observe jumps in the electric field in low magnetic fields. The scanning electron microscopy results indicate that such a jump originates from cracks in Nb barriers and ex-situ MgB2 barriers. Our research indicates that the field sweep allows us to detect damage to barriers that are made of superconducting materials. This method can be the basis for an industrial method for detecting damages in MgB2 wires. These defects reduce the critical current of MgB2 wire. Detection and removal of these defects will allow us to produce MgB2 wires with ex-situ MgB2 and Nb barriers that will have improved critical current density. Manufacturing of MgB2 wires with new ex-situ MgB2 barriers is a new technological concept. This type of barrier is cheaper and easier to manufacture, leading to cheaper MgB2 wires. Moreover, we show that critical current can be measured by two methods: current sweep (constant magnetic field and quickly increasing current) and field sweep. - Graphical abstract: Our results indicate that the jump electric field low magnetic fields. This jump indicates damage in Nb and ex situ MgB2 barrier. Detection and removal of defects will increase Jc in MgB2 wires and will increase the applicability of MgB2 wire. - Highlights: • Jump electric field in the 1 T indicates damage to the Nb barrier. • Jump resistance at 9 K indicates damage to the Nb barrier. • Jump electric field in low magnetic field indicates damage to ex situ MgB2 barrier. • Damage Nb and ex situ MgB2 barrier significantly reduces the critical current density in the MgB2 wire

  11. Barriers to the Development of Marital Health as a Health Field

    Science.gov (United States)

    Vincent, Clark E.

    1977-01-01

    The development of marital health as a bona fide health field is posited as the most viable means for obtaining funding for training, research and treatment concerning the marital dyad equal to such funding now available for other health fields. (Author)

  12. Model and analysis of drain induced barrier lowering effect for 4H-SiC metal semiconductor field effct transistor

    Institute of Scientific and Technical Information of China (English)

    Cao Quan-Jun; Zhang Yi-Men; Jia Li-xin

    2009-01-01

    Based on an analytical solution of the two-dimensional Poisson equation in the subthreshold region. this paper investigates the behavior of DIBL(drain induced barrier lowering)effect for short channel 4H-SiC metal semiconductor field effect transistors(MESFETs). An accurate analytical model of threshold voltage shift for the asymmetric short channel 4H-SiC MESFET is presented and thus verified. According to the presented model. it analyses the threshold voltage for short channel device on the L/a(channel length/channel depth)ratio, drain applied voltage VDS and channel doping concentration ND, thus providing a good basis for the design and modelling of short channel 4H-SiC MESFETs device.

  13. Capillary saturation and desaturation.

    Science.gov (United States)

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

    2015-12-01

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

  14. Modulated heat pulse propagation and partial transport barriers in chaotic magnetic fields

    OpenAIRE

    del-Castillo-Negrete, D.; Blazevski, D.

    2016-01-01

    Direct numerical simulations of the time dependent parallel heat transport equation modeling heat pulses driven by power modulation in 3-dimensional chaotic magnetic fields are presented. The numerical method is based on the Fourier formulation of a Lagrangian-Green's function method that provides an accurate and efficient technique for the solution of the parallel heat transport equation in the presence of harmonic power modulation. The numerical results presented provide conclusive evidence...

  15. Ultrastructural localization of cholinergic muscarinic receptors in rat brain cortical capillaries

    OpenAIRE

    Luiten, PGM; DEJONG, GI; VANDERZEE, EA; vanDijken, H; van Dijken, H.

    1996-01-01

    Cholinergic innervation of the cerebrovasculature is known to regulate vascular tone, perfusion rate and permeability of the microvascular wall. Notably the cholinergic innervation of cerebral capillaries is of interest since these capillaries form the blood-brain barrier. Although there is a general consensus as to the presence of nicotinic and muscarinic receptors in the domain of the capillary wall, their precise anatomical position is unknown. The subcellular localization of muscarinic re...

  16. Annotated bibliography of selected references on shoreline barrier island deposits with emphasis on Patrick Draw Field, Sweetwater County, Wyoming

    Energy Technology Data Exchange (ETDEWEB)

    Rawn-Schatzinger, V.; Schatzinger, R.A.

    1993-07-01

    This bibliography contains 290 annotated references on barrier island and associated depositional environments and reservoirs. It is not an exhaustive compilation of all references on the subject, but rather selected papers on barrier islands, and the depositional processes of formation. Papers that examine the morphology and internal architecture of barrier island deposits, exploration and development technologies are emphasized. Papers were selected that aid in understanding reservoir architecture and engineering technologies to help maximize recovery efficiency from barrier island oil reservoirs. Barrier islands from Wyoming, Montana and the Rocky Mountains basins are extensively covered.

  17. Ultrastructural localization of cholinergic muscarinic receptors in rat brain cortical capillaries

    NARCIS (Netherlands)

    Luiten, PGM; deJong, GI; VanderZee, EA; vanDijken, H; Dijken, H. van

    1996-01-01

    Cholinergic innervation of the cerebrovasculature is known to regulate vascular tone, perfusion rate and permeability of the microvascular wall. Notably the cholinergic innervation of cerebral capillaries is of interest since these capillaries form the blood-brain barrier. Although there is a genera

  18. Relative Contribution of the Magnetic Field Barrier and Solar Wind Speed in ICME-associated Forbush Decreases

    Science.gov (United States)

    Bhaskar, Ankush; Subramanian, Prasad; Vichare, Geeta

    2016-09-01

    We study 50 cosmic-ray Forbush decreases (FDs) from the Oulu neutron monitor data during 1997-2005 that were associated with Earth-directed interplanetary coronal mass ejections (ICMEs). Such events are generally thought to arise due to the shielding of cosmic rays by a propagating diffusive barrier. The main processes at work are the diffusion of cosmic rays across the large-scale magnetic fields carried by the ICME and their advection by the solar wind. In an attempt to better understand the relative importance of these effects, we analyze the relationship between the FD profiles and those of the interplanetary magnetic field (B) and the solar wind speed (V sw). Over the entire duration of a given FD, we find that the FD profile is generally (anti)correlated with the B and V sw profiles. This trend holds separately for the FD main and recovery phases too. For the recovery phases, however, the FD profile is highly anti-correlated with the V sw profile, but not with the B profile. While the total duration of the FD profile is similar to that of the V sw profile, it is significantly longer than that of the B profile. Using the convection-diffusion model, a significant contribution of advection by solar wind is found during the recovery phases of the FD.

  19. The roles of the magnetic field barrier and solar wind speed in ICME-associated Forbush decreases

    CERN Document Server

    Bhaskar, Ankush; Vichare, Geeta

    2016-01-01

    We study 50 cosmic ray Forbush decreases (FDs) from the Oulu neutron monitor data during 1997-2005 that were associated with Earth-directed interplanetary coronal mass ejections (ICMEs). Such events are generally thought to arise due to the shielding of cosmic rays by a propagating diffusive barrier. The main processes at work are the diffusion of cosmic rays across the large-scale magnetic fields carried by the ICME and their advection by the solar wind. In an attempt to better understand the relative importance of these effects, we analyse the relationship between the FD profiles and those of the interplanetary magnetic field (B) and the solar wind speed (Vsw). Over the entire duration of a given FD, we find that the FD profile is generally well (anti)correlated with the B and Vsw profiles. This trend holds separately for the FD main and recovery phases too. For the recovery phases, however, the FD profile is highly anti-correlated with the Vsw profile, but not with the B profile. While the total duration o...

  20. How Capillary Rafts Sink

    CERN Document Server

    Protiere, S; Aristoff, J; Stone, H

    2010-01-01

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

  1. Derivatization in Capillary Electrophoresis.

    Science.gov (United States)

    Marina, M Luisa; Castro-Puyana, María

    2016-01-01

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

  2. Nonaqueous Capillary Electrophoresis Mass Spectrometry.

    Science.gov (United States)

    Klampfl, Christian W; Himmelsbach, Markus

    2016-01-01

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

  3. The impact of farmers’ participation in field trials in creating awareness and stimulating compliance with the World Health Organization’s farm-based multiple-barrier approach

    DEFF Research Database (Denmark)

    Amponsah, Owusu; Vigre, Håkan; Schou, Torben Wilde;

    2016-01-01

    The results of a study aimed as assessing the extent to which urban vegetable farmers’ participation in field trials can impact on their awareness and engender compliance with the World Health Organization’s farm-based multiple-barrier approach are presented in this paper. Both qualitative...

  4. Cellular Apoptosis and Blood Brain Barrier Permeability Changes in the Pre-Incubated Chicken Embryo’s Brain by Effect of Electromagnetic Fields

    OpenAIRE

    Sima Kalantari; Mohammad Reza Bigdeli; Maryam Shams-Lahijani

    2015-01-01

    Background: Electromagnetic fields (EMF) have teratogenic effects during the embryonic development. In current study, histopathological and physiological effects of sinusoidal EMF on the brain were investigated. We sought to determine the apoptosis level and changes in blood brain barrier permeability in brain tissue of pre-incubated white leghorn hen eggs in the field of EMF. Materials and Methods: In this experimental study, 300 healthy, fresh, and fertilized eggs (55-65 g) were divided ...

  5. Schottky barrier contrasts in single and bi-layer graphene contacts for MoS2 field-effect transistors

    Science.gov (United States)

    Du, Hyewon; Kim, Taekwang; Shin, Somyeong; Kim, Dahye; Kim, Hakseong; Sung, Ji Ho; Lee, Myoung Jae; Seo, David H.; Lee, Sang Wook; Jo, Moon-Ho; Seo, Sunae

    2015-12-01

    We have investigated single- and bi-layer graphene as source-drain electrodes for n-type MoS2 transistors. Ti-MoS2-graphene heterojunction transistors using both single-layer MoS2 (1M) and 4-layer MoS2 (4M) were fabricated in order to compare graphene electrodes with commonly used Ti electrodes. MoS2-graphene Schottky barrier provided electron injection efficiency up to 130 times higher in the subthreshold regime when compared with MoS2-Ti, which resulted in VDS polarity dependence of device parameters such as threshold voltage (VTH) and subthreshold swing (SS). Comparing single-layer graphene (SG) with bi-layer graphene (BG) in 4M devices, SG electrodes exhibited enhanced device performance with higher on/off ratio and increased field-effect mobility (μFE) due to more sensitive Fermi level shift by gate voltage. Meanwhile, in the strongly accumulated regime, we observed opposing behavior depending on MoS2 thickness for both SG and BG contacts. Differential conductance (σd) of 1M increases with VDS irrespective of VDS polarity, while σd of 4M ceases monotonic growth at positive VDS values transitioning to ohmic-like contact formation. Nevertheless, the low absolute value of σd saturation of the 4M-graphene junction demonstrates that graphene electrode could be unfavorable for high current carrying transistors.

  6. Schottky barrier contrasts in single and bi-layer graphene contacts for MoS2 field-effect transistors

    International Nuclear Information System (INIS)

    We have investigated single- and bi-layer graphene as source-drain electrodes for n-type MoS2 transistors. Ti-MoS2-graphene heterojunction transistors using both single-layer MoS2 (1M) and 4-layer MoS2 (4M) were fabricated in order to compare graphene electrodes with commonly used Ti electrodes. MoS2-graphene Schottky barrier provided electron injection efficiency up to 130 times higher in the subthreshold regime when compared with MoS2-Ti, which resulted in VDS polarity dependence of device parameters such as threshold voltage (VTH) and subthreshold swing (SS). Comparing single-layer graphene (SG) with bi-layer graphene (BG) in 4M devices, SG electrodes exhibited enhanced device performance with higher on/off ratio and increased field-effect mobility (μFE) due to more sensitive Fermi level shift by gate voltage. Meanwhile, in the strongly accumulated regime, we observed opposing behavior depending on MoS2 thickness for both SG and BG contacts. Differential conductance (σd) of 1M increases with VDS irrespective of VDS polarity, while σd of 4M ceases monotonic growth at positive VDS values transitioning to ohmic-like contact formation. Nevertheless, the low absolute value of σd saturation of the 4M-graphene junction demonstrates that graphene electrode could be unfavorable for high current carrying transistors

  7. Capillary permeability in adipose tissue

    DEFF Research Database (Denmark)

    Paaske, W P; Nielsen, S L

    1976-01-01

    of about 7 ml/100 g-min. This corresponds to a capillary diffusion capacity of 2.0 ml/100 g-min which is half the value reported for vasodilated skeletal muscle having approximately twice as great capillary surface area. Thus, adipose tissue has about the same capillary permeability during slight metabolic...

  8. Capillary electrophoresis - electrospray ionization mass spectrometry in small diameter capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, J.H.; Goodlett, D.R.; Udseth, H.R.; Smith, R.D.

    1992-06-01

    Methods (such as small inner diameter capillaries) are being explored to increase analyte sensitivity in capillary electrophoresis- electrospray ionization/mass spectroscopy(CE-ESI/MS). Results are reported for melittin in a protein mixture, with 10 to 100 {mu}m ID capillaries; and for a mixture of aprotinin, cytochrome c, myoglobin, and carbonic anhydrase, with 5 to 50 {mu}m ID capillaries. It is shown that an increase in solute sensitivity occurs when small ID capillaries ({lt} 20 {mu}m) are used in CE-ESI/MS for both a peptide and a protein mixture. 3 figs. (DLC)

  9. Summary report on close-coupled subsurface barrier technology: Initial field trials to full-scale demonstration

    International Nuclear Information System (INIS)

    The primary objective of this project was to develop and demonstrate the installation and measure the performance of a close-coupled barrier for the containment of subsurface waste or contaminant migration. A close-coupled barrier is produced by first installing a conventional, low-cost, cement-grout containment barrier followed by a thin lining of a polymer grout. The resultant barrier is a cement-polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. The technology has matured from a regulatory investigation of the issues concerning the use of polymers to laboratory compatibility and performance measurements of various polymer systems to a pilot-scale, single column injection at Sandia to full-scale demonstration. The feasibility of the close-coupled barrier concept was proven in a full-scale cold demonstration at Hanford, Washington and then moved to the final stage with a full-scale demonstration at an actual remediation site at Brookhaven National Laboratory (BNL). At the Hanford demonstration the composite barrier was emplaced around and beneath a 20,000 liter tank. The secondary cement layer was constructed using conventional jet grouting techniques. Drilling was completed at a 45 degree angle to the ground, forming a cone-shaped barrier. The primary barrier was placed by panel jet-grouting with a dual-wall drill stem using a two part polymer grout. The polymer chosen was a high molecular weight acrylic. At the BNL demonstration a V-trough barrier was installed using a conventional cement grout for the secondary layer and an acrylic-gel polymer for the primary layer. Construction techniques were identical to the Hanford installation. This report summarizes the technology development from pilot- to full-scale demonstrations and presents some of the performance and quality achievements attained

  10. Summary report on close-coupled subsurface barrier technology: Initial field trials to full-scale demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Heiser, J.H. [Brookhaven National Lab., Upton, NY (United States). Environmental and Waste Technology Center; Dwyer, B. [Sandia National Lab., Albuquerque, NM (United States)

    1997-09-01

    The primary objective of this project was to develop and demonstrate the installation and measure the performance of a close-coupled barrier for the containment of subsurface waste or contaminant migration. A close-coupled barrier is produced by first installing a conventional, low-cost, cement-grout containment barrier followed by a thin lining of a polymer grout. The resultant barrier is a cement-polymer composite that has economic benefits derived from the cement and performance benefits from the durable and resistant polymer layer. The technology has matured from a regulatory investigation of the issues concerning the use of polymers to laboratory compatibility and performance measurements of various polymer systems to a pilot-scale, single column injection at Sandia to full-scale demonstration. The feasibility of the close-coupled barrier concept was proven in a full-scale cold demonstration at Hanford, Washington and then moved to the final stage with a full-scale demonstration at an actual remediation site at Brookhaven National Laboratory (BNL). At the Hanford demonstration the composite barrier was emplaced around and beneath a 20,000 liter tank. The secondary cement layer was constructed using conventional jet grouting techniques. Drilling was completed at a 45{degree} angle to the ground, forming a cone-shaped barrier. The primary barrier was placed by panel jet-grouting with a dual-wall drill stem using a two part polymer grout. The polymer chosen was a high molecular weight acrylic. At the BNL demonstration a V-trough barrier was installed using a conventional cement grout for the secondary layer and an acrylic-gel polymer for the primary layer. Construction techniques were identical to the Hanford installation. This report summarizes the technology development from pilot- to full-scale demonstrations and presents some of the performance and quality achievements attained.

  11. Mach-like capillary-gravity wakes.

    Science.gov (United States)

    Moisy, Frédéric; Rabaud, Marc

    2014-08-01

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

  12. Field study of moisture damage in walls insulated without a vapor barrier. Final report for the Oregon Department of Energy

    Energy Technology Data Exchange (ETDEWEB)

    Tsongas, G.A.

    1980-05-01

    Considerable uncertainty has existed over whether or not wall insulation installed without a vapor barrier causes an increased risk of moisture damage (wood decay) within walls. This report describes the results of one of the first major studies in the country aimed at finding out if such a moisture problem really exists. The exterior walls of a total of 96 homes in Portland, Oregon were opened, of which 70 had retrofitted insulation and 26 were uninsulated and were a control group. The types of insulation included urea-formaldehyde foam (44), mineral wool (16), and cellulose (10). In each opened wall cavity the moisture content of wood was measured and insulation and wood samples were taken for laboratory analysis of moisture content and for the determination of the presence of absence of decay fungi. Foam shrinkage was also measured. To evaluate the possible influence of the relative air tightness of the homes, fan depressurization tests were run using a door blower unit. The field and laboratory test results indicating the lack of a moisture damage problem in existing homes with wood siding in climates similar to that of western Oregon are described along with results of a statistical analysis of the data. Related problems of interest to homeowners and insulation installers are noted. The standard operating procedures used throughout the study are discussed, including the home selection process, quantitative and qualitative techniques used to identify wall locations with the highest moisture content, wall opening and data/sample collection methodology, laboratory analysis of samples, data processing and analysis, and applicability of the results. Recommendations for furutre tests are made. Finally, the potential and desirability for future retrofitting of wall insulation is explored.

  13. due to Capillary Forces

    Directory of Open Access Journals (Sweden)

    Hassen M. Ouakad

    2009-01-01

    Full Text Available We present modeling and analysis for the static behavior and collapse instabilities of doubly-clamped and cantilever microbeams subjected to capillary forces. These forces can be as a result of a volume of liquid trapped underneath the microbeam during the rinsing and drying process in fabrication. The model considers the microbeam as a continuous medium, the capillary force as a nonlinear function of displacement, and accounts for the mid-plane stretching and geometric nonlinearities. The capillary force is assumed to be distributed over a specific length underneath the microbeam. The Galerkin procedure is used to derive a reduced-order model consisting of a set of nonlinear algebraic and differential equations that describe the microbeams static and dynamic behaviors. We study the collapse instability, which brings the microbeam from its unstuck configuration to touch the substrate and gets stuck in the so-called pinned configuration. We calculate the pull-in length that distinguishes the free from the pinned configurations as a function of the beam thickness and gap width for both microbeams. Comparisons are made with analytical results reported in the literature based on the Ritz method for linear and nonlinear beam models. The instability problem, which brings the microbeam from a pinned to adhered configuration is also investigated. For this case, we use a shooting technique to solve the boundary-value problem governing the deflection of the microbeams. The critical microbeam length for this second instability is also calculated.

  14. Role of two-photon electronic transitions in the formation of active dynamic conductivity in a three-barrier resonance tunneling structure with an applied Dc electric field

    International Nuclear Information System (INIS)

    The theory of active dynamic conductivity in a three-barrier resonance tunneling structure subjected to the combined action of a weak electromagnetic field and a longitudinal dc electric field is developed with regard for the contribution of laser induced one- and two-photon electronic transitions with different frequencies. For this purpose, the full Schroedinger equation is solved in the effective mass approximation and with the use of the model of rectangular potential wells and barriers for an electron. The maximum contribution of two-photon transitions to the formation of the total active dynamic conductivity in laser-induced transitions is shown not to exceed 38%. Geometric configurations of the resonance tunneling structure, for which the laser radiation intensity increases due to laser induced two-photon electronic transitions, are determined

  15. Grain boundary barrier modification due to coupling effect of crystal polar field and water molecular dipole in ZnO-based structures

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Xu; Zhu, Yuan, E-mail: zhuy9@mail.sysu.edu, E-mail: phzktang@ust.hk; Chen, Mingming; Su, Longxing; Chen, Anqi; Zhao, Chengchun; Gui, Xuchun; Xiang, Rong; Huang, Feng [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Tang, Zikang, E-mail: zhuy9@mail.sysu.edu, E-mail: phzktang@ust.hk [State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2014-06-16

    Surface water molecules induced grain boundaries (GBs) barrier modification was investigated in ZnO and ZnMgO/ZnO films. Tunable electronic transport properties of the samples by water were characterized via a field effect transistor (FET) device structure. The FETs fabricated from polar C-plane ZnO and ZnMgO/ZnO films that have lots of GBs exhibited obvious double Schottky-like current-voltage property, whereas that fabricated from nonpolar M-plane samples with GBs and ZnO bulk single-crystal had no obvious conduction modulation effects. Physically, these hallmark properties are supposed to be caused by the electrostatical coupling effect of crystal polar field and molecular dipole on GBs barrier.

  16. A planar Al-Si Schottky barrier metal–oxide–semiconductor field effect transistor operated at cryogenic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Purches, W. E. [School of Physics, UNSW, Sydney 2052 (Australia); Rossi, A.; Zhao, R. [School of Electrical Engineering and Telecommunications, UNSW, Sydney 2052 (Australia); Kafanov, S.; Duty, T. L. [School of Physics, UNSW, Sydney 2052 (Australia); Centre for Engineered Quantum Systems (EQuS), School of Physics, UNSW, Sydney 2052 (Australia); Dzurak, A. S. [School of Electrical Engineering and Telecommunications, UNSW, Sydney 2052 (Australia); Australian Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), UNSW, Sydney 2052 (Australia); Rogge, S.; Tettamanzi, G. C., E-mail: g.tettamanzi@unsw.edu.au [School of Physics, UNSW, Sydney 2052 (Australia); Australian Centre of Excellence for Quantum Computation and Communication Technology (CQC2T), UNSW, Sydney 2052 (Australia)

    2015-08-10

    Schottky Barrier-MOSFET technology offers intriguing possibilities for cryogenic nano-scale devices, such as Si quantum devices and superconducting devices. We present experimental results on a device architecture where the gate electrode is self-aligned with the device channel and overlaps the source and drain electrodes. This facilitates a sub-5 nm gap between the source/drain and channel, and no spacers are required. At cryogenic temperatures, such devices function as p-MOS Tunnel FETs, as determined by the Schottky barrier at the Al-Si interface, and as a further advantage, fabrication processes are compatible with both CMOS and superconducting logic technology.

  17. Plasma Dynamics of Capillary Discharges for the BELLA project

    Science.gov (United States)

    Stoltz, Peter; Hakim, Ammar; Loverich, John; Fillmore, David; Johnson, Jeffrey; Geddes, Cameron; Esarey, Eric; Mittelberger, Daniel; Bulanov, Stepan; Gonsalves, Anthony; Leemans, Wim

    2010-11-01

    Capillary discharges to form a meter-scale plasma waveguide are important for 10 GeV scale laser plasma accelerator experiments on the BELLA laser in progress at Lawrence Berkeley National Laboratory. We present simulation results of capillary plasma properties, including radial density and temperature profiles, using the Nautilus code. An effect known to play a dominant role is the transfer of heat from the plasma to the capillary wall. We present benchmark results for heat transfer modeling with Nautilus in the regime of interest to capillary discharges. We also discuss the relative importance of diffusion, Ohm's law, and applied solenoidal fields on the radial profiles needed for experiments. For instance, some previous models estimate applied solenoidal fields could increase on-axis temperatures by roughly a factor of two, and we compare with these estimates. Finally, we compare radial profile results with other simulation results and with recent measurements made at LBNL.

  18. Solid-phase based on-chip DNA purification through a valve-free stepwise injection of multiple reagents employing centrifugal force combined with a hydrophobic capillary barrier pressure.

    Science.gov (United States)

    Zhang, Hainan; Tran, Hong Hanh; Chung, Bong Hyun; Lee, Nae Yoon

    2013-03-21

    In this paper, we demonstrate a simple technique for sequentially introducing multiple sample liquids into microchannels driven by centrifugal force combined with a hydrophobic barrier pressure and apply the technique for performing solid-phase based on-chip DNA purification. Three microchannels with varying widths, all equipped with independent sample reservoirs at the inlets, were fabricated on a hydrophobic elastomer, poly(dimethylsiloxane) (PDMS). First, glass beads were packed inside the reaction chamber, and a whole cell containing the DNA extract was introduced into the widest channel by applying centrifugal force for physical adsorption of the DNA onto the glass beads. Next, washing and elution solutions were sequentially introduced into the intermediate and narrowest microchannels, respectively, by gradually increasing the amount of centrifugal force. Through a precise manipulation of the centrifugal force, the DNA adsorbed onto the glass beads was successfully washed and eluted in a continuous manner without the need to introduce each solution manually. A stepwise injection of liquids was successfully demonstrated using multiple ink solutions, the results of which corresponded well with the theoretical analyses. As a practical application, the D1S80 locus of human genomic DNA, which is widely used for forensic purposes, was successfully purified using the microdevice introduced in this study, as demonstrated through successful target amplification. This will pave the way for the construction of a control-free valve system for realizing on-chip DNA purification, which is one of the most labor-intensive and hard-to-miniaturize components, on a greatly simplified and miniaturized platform employing hydrophobic PDMS.

  19. FIELD TEST INSTRUCTION 100-NR-2 OPERABLE UNIT DESIGN OPTIMIZATION STUDY FOR SEQUESTRATION OF SR-90 SATURATED ZONE APATITE PERMEABLE REACTIVE BARRIER EXTENSION

    Energy Technology Data Exchange (ETDEWEB)

    BOWLES NA

    2010-10-06

    The objective of this field test instruction is to provide technical guidance for aqueous injection emplacement of an extension apatite permeable reactive barrier (PRE) for the sequestration of strontium-90 (Sr-90) using a high concentration amendment formulation. These field activities will be conducted according to the guidelines established in DOE/RL-2010-29, 100-NR-2 Design Optimization Study, hereafter referred to as the DOS. The DOS supports the Federal Facility Agreement Consent Order (EPA et al., 1989), Milestone M-16-06-01, and 'Complete Construction of a Permeable Reactive Barrier at 100-N.' Injections of apatite precursor chemicals will occur at an equal distance intervals on each end of the existing PRE to extend the PRB from the existing 91 m (300 ft) to at least 274 m (900 ft). Field testing at the 100-N Area Apatite Treatability Test Site, as depicted on Figure 1, shows that the barrier is categorized by two general hydrologic conceptual models based on overall well capacity and contrast between the Hanford and Ringold hydraulic conductivities. The upstream portion of the original barrier, shown on Figure 1, is characterized by relatively low overall well specific capacity. This is estimated from well development data and a lower contrast in hydraulic conductivity between the Hanford formation and Ringold Formations. Comparison of test results from these two locations indicate that permeability contrast between the Hanford formation and Ringold Formation is significantly less over the upstream one-third of the barrier. The estimated hydraulic conductivity for the Hanford formation and Ringold Formation over the upstream portion of the barrier based on observations during emplacement of the existing 91 m (300 ft) PRB is approximately 12 and 10 m/day (39 and 32 ft/day), respectively (PNNL-17429). However, these estimates should be used as a rough guideline only, as significant variability in hydraulic conductivity is likely to be observed in

  20. Experimental validation of non-uniformity effect of the radial electric field on the edge transport barrier formation in JT-60U H-mode plasmas

    Science.gov (United States)

    Kamiya, K.; Itoh, K.; Itoh, S.-I.

    2016-08-01

    The turbulent structure formation, where strongly-inhomogeneous turbulence and global electromagnetic fields are self-organized, is a fundamental mechanism that governs the evolution of high-temperature plasmas in the universe and laboratory (e.g., the generation of edge transport barrier (ETB) of the H-mode in the toroidal plasmas). The roles of inhomogeneities of radial electric field (Er) are known inevitable. In this mechanism, whether the first derivative of Er (shear) or the second derivative of Er (curvature) works most is decisive in determining the class of nontrivial solutions (which describe the barrier structure). Here we report the experimental identification of the essential role of the Er-curvature on the ETB formation, for the first time, based on the high-spatiotemporal resolution spectroscopic measurement. We found the decisive importance of Er-curvature on ETB formation during ELM-free phase, but there is only a low correlation with the Er-shear value at the peak of normalized ion temperature gradient. Furthermore, in the ELMing phase, the effect of curvature is also quantified in terms of the relationship between pedestal width and thickness of the layer of inhomogeneous Er. This is the fundamental basis to understand the structure of transport barriers in fusion plasmas.

  1. Influence of Schottky drain contacts on the strained AlGaN barrier layer of AlGaN/AlN/GaN heterostructure field-effect transistors

    Institute of Scientific and Technical Information of China (English)

    Cao Zhi-Fang; Lin Zhao-Jun; Li Yuan-Jie; Luan Chong-Biao; Wang Zhan-Guo

    2013-01-01

    Rectangular Schottky drain A1GaN/AlN/GaN heterostructure field-effect transistors (HFETs) with different gate contact areas and conventional A1GaN/A1N/GaN HFETs as control were both fabricated with same size.It was found there is a significant difference between Schottky drain A1GaN/A1N/GaN HFETs and the control group both in drain series resistance and in two-dimensional electron gas (2DEG) electron mobility in the gate--drain channel.We attribute this to the different influence of Ohmic drain contacts and Schottky drain contacts on the strained A1GaN barrier layer.For conventional AlGaN/AlN/GaN HFETs,annealing drain Ohmic contacts gives rise to a strain variation in the A1GaN barrier layer between the gate contacts and the drain contacts,and results in strong polarization Coulomb field scattering in this region.In Schottky drain A1GaN/A1N/GaN HFETs,the strain in the A1GaN barrier layer is distributed more regularly.

  2. Tapered capillary optics

    Science.gov (United States)

    Hirsch, Gregory

    1998-01-01

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

  3. Highly sensitive detection of five typical fluoroquinolones in low-fat milk by field-enhanced sample injection based CE in bubble cell capillary

    OpenAIRE

    DENG, YAN; Gasilova, Natalia; Qiao, Liang; Zhou, Ying-Lin; Zhang, Xin-Xiang; Girault, Hubert H.

    2014-01-01

    Fluoroquinolones are a group of synthetic antibiotics with a broad activity spectrum against mycoplasma, gram-positive and gram-negative bacteria. Due to the extensive use of fluoroquinolones in farming and veterinary science, there is a constant need in the analytical methods able to efficiently monitor their residues in food products of animal origin, regulated by Commission Regulation (European Union) no. 37/2010. Herein, field-enhanced sample injection for sample stacking prior the CZE se...

  4. Barriers to radiant barriers

    Energy Technology Data Exchange (ETDEWEB)

    Henke, C.

    Radiant barriers are an energy saving device which decrease the heat lost through radiant heat transfer. The primary reason to install it is to save on air conditioning costs, as it prevents the loss of heat through the attic. They have been the subject of much controversy, as the claims made by many manufacturers were extreme (up to 100% heat shielding), with the consumer paying high prices for ineffective devices. The authors outline criteria for the consumer to consider when buying radiant warmers and then give installation tips for both new constructions and retrofits.

  5. Capillary optics for radiation focusing

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-11-01

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

  6. Ion guiding in alumina capillaries

    DEFF Research Database (Denmark)

    Juhász, Z.; Sulik, B.; Biri, S.;

    2009-01-01

    Transmission of a few keV impact energy Ne ions through capillaries in anodic alumina membranes has been studied with different ion counting methods using an energy dispersive electrostatic spectrometer, a multichannel plate (MCP) array and sensitive current-measurement. In the present work, we...... focus our attention to the measurements with the MCP array. The alumina capillaries were prepared by electro-chemical oxidation of aluminium foils. For the present experiments guiding of 3-6 keV Ne ions has been studied in two samples with capillary diameter of about 140 nm and 260 nm and with capillary...... length of about 15 μm. At these energies, the ions have been efficiently guided by the capillaries up to few degrees tilt angle. In this work, we compare the results obtained by the energy dispersive spectrometer to those studied by the MCP array. © 2008 Elsevier B.V. All rights reserved....

  7. Biomedical applications of capillary electrophoresis

    Science.gov (United States)

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

    2015-08-01

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

  8. Field-enhanced sample injection micelle-to-solvent stacking capillary zone electrophoresis-electrospray ionization mass spectrometry of antibiotics in seawater after solid-phase extraction.

    Science.gov (United States)

    Wuethrich, Alain; Haddad, Paul R; Quirino, Joselito P

    2016-05-01

    The synergistic stacking approach of field-enhanced sample injection-micelle-to-solvent stacking was used for high sensitivity CZE-ESI-MS of eight penicillins and sulfonamides. Sensitivity enhancement factors (peak height) were 1629-3328 compared to typical injection, with LODs from 0.11 to 0.55 ng/mL. The analytical figures of merit were acceptable. SPE on a fortified seawater sample resulted in 50-fold enrichment with recoveries of 85-110%. The overall method LODs were 0.002-0.011 ng/mL. PMID:27135307

  9. Capillary Electrophoresis in Food and Foodomics.

    Science.gov (United States)

    Ibáñez, Clara; Acunha, Tanize; Valdés, Alberto; García-Cañas, Virginia; Cifuentes, Alejandro; Simó, Carolina

    2016-01-01

    Quality and safety assessment as well as the evaluation of other nutritional and functional properties of foods imply the use of robust, efficient, sensitive, and cost-effective analytical methodologies. Among analytical technologies used in the fields of food analysis and foodomics, capillary electrophoresis (CE) has generated great interest for the analyses of a large number of compounds due to its high separation efficiency, extremely small sample and reagent requirements, and rapid analysis. The introductory section of this chapter provides an overview of the recent applications of capillary electrophoresis (CE) in food analysis and foodomics. Relevant reviews and research articles on these topics are tabulated including papers published in the period 2011-2014. In addition, to illustrate the great capabilities of CE in foodomics the chapter describes the main experimental points to be taken into consideration for a metabolomic study of the antiproliferative effect of carnosic acid (a natural diterpene found in rosemary) against HT-29 human colon cancer cells. PMID:27645749

  10. Electrokinetic Flow and Dispersion in Capillary Electrophoresis

    Science.gov (United States)

    Ghosal, Sandip

    2006-01-01

    Electrophoretic separation of a mixture of chemical species is a fundamental technique of great usefulness in biology, health care, and forensics. In capillary electrophoresis (which has evolved from its predecessor, slab-gel electrophoresis), the sample migrates through a single microcapillary instead of through the network of pores in a gel. A fundamental design problem is to minimize dispersion in the separation direction. Molecular diffusion is inevitable and sets a theoretical limit on the best separation that can be achieved. But in practice, there are a number of effects arising out of the interplay between fluid flow, chemistry, thermal effects, and electric fields that result in enhanced dispersion. This paper reviews the subject of fluid flow in such capillary microchannels and examines the various causes of enhanced dispersion that limit the efficiency of separation.

  11. Uniform and non-uniform modes of nanosecond-pulsed dielectric barrier discharge in atmospheric air: fast imaging and spectroscopic measurements of electric field.

    Science.gov (United States)

    Liu, Chong; Dobrynin, Danil; Fridman, Alexander

    2014-06-25

    In this study, we report experimental results on fast ICCD imaging of development of nanosecond-pulsed dielectric barrier discharge (DBD) in atmospheric air and spectroscopic measurements of electric field in the discharge. Uniformity of the discharge images obtained with nanosecond exposure times were analyzed using chi-square test. The results indicate that DBD uniformity strongly depends on applied (global) electric field in the discharge gap, and is a threshold phenomenon. We show that in the case of strong overvoltage on the discharge gap (provided by fast rise times), there is transition from filamentary to uniform DBD mode which correlates to the corresponding decrease of maximum local electric field in the discharge. PMID:25071294

  12. Hydrogel plug for independent sample and buffer handling in continuous microchip capillary electrophoresis

    Science.gov (United States)

    Puchberger-Enengl, Dietmar; Bipoun, Mireille; Smolka, Martin; Krutzler, Christian; Keplinger, Franz; Vellekoop, Michael J.

    2013-05-01

    In microchip capillary electrophoresis most frequently electrokinetic sample injection is utilized, which does not allow pressure driven sample handling and is sensitive for pressure drops due to different reservoir levels. For efficient field tests a multitude of samples have to be processed with the least amount of external equipment. We present the use of a hydrogel plug to separate the sample from clean buffer to enable independent sample change and buffer refreshment. In-situ polymerization of the gel does away with complex membrane fabrication techniques. The sample is electrokinetically injected through the gel and subsequently separated by a voltage between the second gel inlet and the buffer outlet. By blocking of disturbing flows by the gel barrier a well-defined ion plug is obtained. After each experiment, the sample and the separation channel can be flushed independently, allowing for a continuous operation mode in order to process multiple samples.

  13. Effects of ischemia on capillary density and flow velocity in nailfolds of human toes.

    Science.gov (United States)

    Richardson, D; Schwartz, R; Hyde, G

    1985-07-01

    The purpose of this study was to investigate reactive hyperemia in the capillary network of human skin in terms of the flow per capillary and the density of flow-active capillaries. Seventeen male subjects 20 to 40 years of age were seated with their right foot placed on the stage of a Leitz epi-ilumination microscope such that the nailfold capillary field in their large toes could be viewed. These vessels were video taped while flow velocity in the right posterior tibial artery was recorded via Doppler ultrasound at rest, then following a 45-sec period of arterial occlusion to the foot. Subsequent to experimentation flow velocity in single nailfold capillaries was measured via video densitometry and the number of flow-active capillaries in the field of view were counted. Following the release of arterial occlusion arterial flow velocity increased 142% above rest, the velocity in single capillaries increased by 54%, and the density of flow-active capillaries, as identified by the presence of red cells, decreased by 37%. The fact that capillary flow velocity increased to a lesser degree than arterial velocity during reactive hyperemia vis-a-vis a decrease in the number of flow-active capillaries indicates that ischemia to the foot elicits a smaller dilatory effect in vascular elements controlling blood flow to the superficial cutaneous region of the toe as compared to other regional vascular networks. PMID:4021840

  14. Instability of the capillary bridge

    Science.gov (United States)

    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.

  15. The order of condensation in capillary grooves.

    Science.gov (United States)

    Rascón, Carlos; Parry, Andrew O; Nürnberg, Robert; Pozzato, Alessandro; Tormen, Massimo; Bruschi, Lorenzo; Mistura, Giampaolo

    2013-05-15

    We consider capillary condensation in a deep groove of width L. The transition occurs at a pressure p(co)(L) described, for large widths, by the Kelvin equation p(sat) - p(co)(L) = 2σ cosθ/L, where θ is the contact angle at the side walls and σ is the surface tension. The order of the transition is determined by the contact angle of the capped end θcap; it is continuous if the liquid completely wets the cap, and first-order otherwise. When the transition is first-order, corner menisci at the bottom of the capillary lead to a pronounced metastability, determined by a complementary Kelvin equation Δp(L) = 2σ sinθcap/L. On approaching the wetting temperature of the capillary cap, the corner menisci merge and a single meniscus unbinds from the bottom of the groove. Finite-size scaling shifts, crossover behaviour and critical singularities are determined at mean-field level and beyond. Numerical and experimental results showing the continuous nature of condensation for θcap = 0 and the influence of corner menisci on adsorption isotherms are presented. PMID:23611878

  16. Role of thirst and visual barriers in the differential behavior displayed by streptozotocin-treated rats in the elevated plus-maze and the open field test.

    Science.gov (United States)

    Rebolledo-Solleiro, Daniela; Crespo-Ramírez, Minerva; Roldán-Roldán, Gabriel; Hiriart, Marcia; Pérez de la Mora, Miguel

    2013-08-15

    Conflicting results have been obtained by several groups when studying the effects of streptozotocin (STZ)-treated rats in the elevated plus-maze (EPM). Since thirst is a prominent feature in STZ-induced diabetic-like condition, we studied whether the walls of the closed arms of the EPM, by limiting the search for water in the environment, may contribute to the observed differential behavioral outcomes. The aim of this study was to ascertain whether visual barriers within the EPM have an influence on the behavior of STZ-treated rats in this test of anxiety. A striking similarity between STZ-treated (50 mg/kg, i.p., in two consecutive days) and water deprived rats (72 h) was found in exploratory behavior in the EPM, showing an anxiolytic-like profile. However the anxiolytic response of STZ-treated rats exposed to the EPM shifts into an anxiogenic profile when they are subsequently tested in the open-field test, which unlike the EPM is devoid of visual barriers. Likewise, water deprived rats (72 h) also showed an anxiogenic profile when they were exposed to the open-field test. Our results indicate that experimental outcomes based on EPM observations can be misleading when studying physiological or pathological conditions, e.g. diabetes, in which thirst may increase exploratory behavior.

  17. Influence of local capillary trapping on containment system effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven [University Of Texas At Austin, Austin, TX (United States). Center for Petroleum and Geosystems Engineering

    2014-03-31

    Immobilization of CO2 injected into deep subsurface storage reservoirs is a critical component of risk assessment for geologic CO2 storage (GCS). Local capillary trapping (LCT) is a recently established mode of immobilization that arises when CO2 migrates due to buoyancy through heterogeneous storage reservoirs. This project sought to assess the amount and extent of LCT expected in storage formations under a range of injection conditions, and to confirm the persistence of LCT if the seal overlying the reservoir were to lose its integrity. Numerical simulation using commercial reservoir simulation software was conducted to assess the influence of injection. Laboratory experiments, modeling and numerical simulation were conducted to assess the effect of compromised seal integrity. Bench-scale (0.6 m by 0.6 m by 0.03 m) experiments with surrogate fluids provided the first empirical confirmation of the key concepts underlying LCT: accumulation of buoyant nonwetting phase at above residual saturations beneath capillary barriers in a variety of structures, which remains immobile under normal capillary pressure gradients. Immobilization of above-residual saturations is a critical distinction between LCT and the more familiar “residual saturation trapping.” To estimate the possible extent of LCT in a storage reservoir an algorithm was developed to identify all potential local traps, given the spatial distribution of capillary entry pressure in the reservoir. The algorithm assumes that the driving force for CO2 migration can be represented as a single value of “critical capillary entry pressure” Pc,entrycrit, such that cells with capillary entry pressure greater/less than Pc,entrycrit act as barriers/potential traps during CO2 migration. At intermediate values of Pc,entrycrit, the barrier regions become more laterally extensive in the reservoir

  18. Solid-liquid surface tensions of critical nuclei and nucleation barriers from a phase-field-crystal study of a model binary alloy using finite system sizes

    Science.gov (United States)

    Choudhary, Muhammad Ajmal; Kundin, Julia; Emmerich, Heike; Oettel, Martin

    2014-08-01

    Phase-field-crystal (PFC) modeling has emerged as a computationally efficient tool to address crystal growth phenomena on atomistic length and diffusive time scales. We use a two-dimensional phase-field-crystal model for a binary system based on Elder et al. [Phys. Rev. B 75, 064107 (2007), 10.1103/PhysRevB.75.064107] to study critical nuclei and their liquid-solid phase boundaries, in particular the nucleus size dependence of the liquid-solid interface tension as well as of the nucleation barrier. Critical nuclei are stabilized in finite systems of various sizes, however, the extracted interface tension as function of the nucleus radius r is independent of system size. We suggest a phenomenological expression to describe the dependence of the extracted interface tension on the nucleus radius r for the liquid-solid system. Moreover, the numerical PFC results show that this dependency can not be fully described by the nonclassical Tolman formula.

  19. Surface Tension and Capillary Rise

    Science.gov (United States)

    Walton, Alan J.

    1972-01-01

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

  20. Capillary Condensation in Confined Media

    CERN Document Server

    Charlaix, Elisabeth

    2009-01-01

    We review here the physics of capillary condensation of liquids in confined media, with a special regard to the application in nanotechnologies. The thermodynamics of capillary condensation and thin film adsorption are first exposed along with all the relevant notions. The focus is then shifted to the modelling of capillary forces, to their measurements techniques (including SFA, AFM and crack tips) and to their influence on AFM imaging techniques as well as on the static and dynamic friction properties of solids (including granular heaps and sliding nanocontacts). A great attention is spent in investigating the delicate role of the surface roughness and all the difficulties involved in the reduction of the probe size to nanometric dimensions. Another major consequence of capillary condensation in nanosystems is the activation of several chemical and corrosive processes that can significantly alter the surface properties, such as dissolution/redeposition of solid materials and stress-corrosion crack propagati...

  1. Cellular Apoptosis and Blood Brain Barrier Permeability Changes in the Pre-Incubated Chicken Embryo’s Brain by Effect of Electromagnetic Fields

    Directory of Open Access Journals (Sweden)

    Sima Kalantari

    2015-02-01

    Full Text Available Background: Electromagnetic fields (EMF have teratogenic effects during the embryonic development. In current study, histopathological and physiological effects of sinusoidal EMF on the brain were investigated. We sought to determine the apoptosis level and changes in blood brain barrier permeability in brain tissue of pre-incubated white leghorn hen eggs in the field of EMF. Materials and Methods: In this experimental study, 300 healthy, fresh, and fertilized eggs (55-65 g were divided into experimental (3 groups, N=50, control (N=75 and sham (N=75 groups. Experimental eggs (inside the coil were exposed to 3 different intensities of 1.33, 2.66 and 7.32 mT and sham groups were also located inside the same coil but with no exposure, for 24 hrs before incubation. Control, sham and experimental groups were incubated in an incubator (38±0.5ºC, 60% humidity. Brains of 14 day old chicken embryos of all groups were removed, fixed in formalin (10%, stained with H & E and TUNEL, apoptotic cells were studied under light microscope. Brains of other embryos were prepared for scanning electron microscope. By injections of Evans blue, any possible changes in brain vessels were also investigated. Results: Our results showed electromagnetic fields have toxic effects on cell organelles and cell membranes. EMF would increase the level of cellular apoptosis in the brain. They also would tear up the blood vessels. Thereafter, they would affect the permeability of blood brain barrier of exposed chicken embryos. Conclusion: These findings suggest that electromagnetic fields induce different degrees of brain damages in chicken embryos brain tissue.

  2. Capillary electrophoresis electrospray ionization mass spectrometry interface

    Science.gov (United States)

    Smith, Richard D.; Severs, Joanne C.

    1999-01-01

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

  3. 200-BP-1 Prototype Hanford Barrier -- 15 Years of Performance Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Ward, Anderson L.; Draper, Kathryn E.; Link, Steven O.; Clayton, Ray E.

    2011-09-30

    Monitoring is an essential component of engineered barrier system design and operation. A composite capacitive cover, including a capillary break and an evapotranspiration (ET) barrier at the Hanford Site, is generating data that can be used to help resolve these issues. The prototype Hanford barrier was constructed over the 216-B-57 Crib in 1994 to evaluate surface-barrier constructability, construction costs, and physical and hydrologic performance at the field scale. The barrier has been routinely monitored between November 1994 and September 1998 as part of a Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) treatability test of barrier performance for the 200 BP 1 Operable Unit. Since FY 1998, monitoring has focused on a more limited set of key water balance, stability, and biotic parameters. In FY 2009, data collection was focused on: (1) water-balance monitoring, consisting of precipitation, runoff, soil moisture storage, and drainage measurements with evapotranspiration calculated by difference; (2) stability monitoring, consisting of asphalt-layer-settlement, basalt-side-slope-stability, and surface-elevation measurements; (3) vegetation dynamics; and (4) animal use. September 2009 marked 15 years since the start of monitoring and the collection of performance data. This report describes the results of monitoring activities during the period October 1, 2008, through September 30, 2009, and summarizes the 15 years of performance data collected from September 1994 through September 2009.

  4. Current role of capillary electrophoretic/electrokinetic techniques in forensic toxicology.

    Science.gov (United States)

    Tagliaro, Franco; Bortolotti, Federica; Pascali, Jennifer P

    2007-08-01

    The current application of capillary electrophoresis in forensic toxicology has been critically reviewed with special focus on the areas where this technique has shown real advantages over chromatographic methods. For example, capillary electrophoresis has been most successfully applied to the chiral analysis of some drugs of forensic interest, including amphetamines and their congeners. Another typical application field of capillary electrophoresis is represented by protein analysis. Recently, special interest has been paid to carbohydrate deficient transferrin (CDT), the most important biological marker of chronic alcohol abuse. Other specific applications of capillary electrophoresis of potential forensic toxicological concern are also discussed. The review includes 62 references. PMID:17572886

  5. Integrated geological-engineering model of Patrick Draw field and examples of similarities and differences among various shoreline barrier systems

    Energy Technology Data Exchange (ETDEWEB)

    Schatzinger, R.A.; Szpakiewicz, M.J.; Jackson, S.R.; Chang, M.M.; Sharma, B.; Tham, M.K.; Cheng, A.M.

    1992-04-01

    The Reservoir Assessment and Characterization Research Program at NIPER employs an interdisciplinary approach that focuses on the high priority reservoir class of shoreline barrier deposits to: (1) determine the problems specific to this class of reservoirs by identifying the reservoir heterogeneities that influence the movement and trapping of fluids; and (2) develop methods to characterize effectively this class of reservoirs to predict residual oil saturation (ROS) on interwell scales and improve prediction of the flow patterns of injected and produced fluids. Accurate descriptions of the spatial distribution of critical reservoir parameters (e.g., permeability, porosity, pore geometry, mineralogy, and oil saturation) are essential for designing and implementing processes to improve sweep efficiency and thereby increase oil recovery. The methodologies and models developed in this program will, in the near- to mid-term, assist producers in the implementation of effective reservoir management strategies such as location of infill wells and selection of optimum enhanced oil recovery methods to maximize oil production from their reservoirs.

  6. Physical Modeling of Gate-Controlled Schottky Barrier Lowering of Metal-Graphene Contacts in Top-Gated Graphene Field-Effect Transistors.

    Science.gov (United States)

    Mao, Ling-Feng; Ning, Huansheng; Huo, Zong-Liang; Wang, Jin-Yan

    2015-12-17

    A new physical model of the gate controlled Schottky barrier height (SBH) lowering in top-gated graphene field-effect transistors (GFETs) under saturation bias condition is proposed based on the energy conservation equation with the balance assumption. The theoretical prediction of the SBH lowering agrees well with the experimental data reported in literatures. The reduction of the SBH increases with the increasing of gate voltage and relative dielectric constant of the gate oxide, while it decreases with the increasing of oxide thickness, channel length and acceptor density. The magnitude of the reduction is slightly enhanced under high drain voltage. Moreover, it is found that the gate oxide materials with large relative dielectric constant (>20) have a significant effect on the gate controlled SBH lowering, implying that the energy relaxation of channel electrons should be taken into account for modeling SBH in GFETs.

  7. A permeable reactive barrier (PRB) media sequence for the remediation of heavy metal and hydrocarbon contaminated water: A field assessment at Casey Station, Antarctica.

    Science.gov (United States)

    Statham, Tom M; Stark, Scott C; Snape, Ian; Stevens, Geoffrey W; Mumford, Kathryn A

    2016-03-01

    A field trial was conducted at Casey Station, Antarctica to assess the suitability of a permeable reactive barrier (PRB) media sequence for the remediation of sites containing both hydrocarbon and heavy metal contamination. An existing PRB was modified to assess a sequence consisting of three sections: (i) Nutrient release/hydrocarbon sorption using ZeoPro™ and granular activated carbon; (ii) Phosphorus and heavy metal capture by granular iron and sand; (iii) Nutrient and excess iron capture by zeolite. The media sequence achieved a greater phosphorus removal capacity than previous Antarctic PRB configurations installed on site. Phosphorus concentrations were reduced during flow through the iron/sand section and iron concentrations were reduced within the zeolite section. However, non-ideal flow was detected during a tracer test and supported by analysis of media and liquid samples from the second summer of operation. Results indicate that the PRB media sequence trialled might be appropriate for other locations, especially less environmentally challenging contaminated sites.

  8. Laser-based capillary polarimeter.

    Science.gov (United States)

    Swinney, K; Hankins, J; Bornhop, D J

    1999-01-01

    A laser-based capillary polarimeter has been configured to allow for the detection of optically active molecules in capillary tubes with a characteristic inner diameter of 250 microm and a 39-nL (10(-9)) sample volume. The simple optical configuration consists of a HeNe laser, polarizing optic, fused-silica capillary, and charge-coupled device (CCD) camera in communication with a laser beam analyzer. The capillary scale polarimeter is based on the interaction between a polarized laser beam and a capillary tube, which results in a 360 degree fan of scattered light. This array of scattered light contains a set of interference fringe, which respond in a reproducible manner to changes in solute optical activity. The polarimetric utility of the instrument will be demonstrated by the analysis of two optically active solutes, R-mandelic acid and D-glucose, in addition to the nonoptically active control, glycerol. The polarimetric response of the system is quantifiable with detection limits facilitating 1.7 x 10(-3) M or 68 x 10(-12) nmol (7 psi 10(-9) g) sensitivity. PMID:11315158

  9. BARRIERS IN TRANSITION FROM PARENTAL LEAVE TO THE LABOR MARKET FROM THE PERSPECTIVE OF UNEMPLOYED PARENTS WITH CHILDREN AND WORKERS IN THE FIELD OF ACTIVE EMPLOYMENT POLICY

    Directory of Open Access Journals (Sweden)

    Krausová Anna

    2014-12-01

    Full Text Available The article brings a presentation and discussion of the results from qualitative research conducted by research team members in the frame of research project (SGS1/FSS/2014, which was funded by Student research Fund by University of Ostrava. The qualitative research covered 21 unemployed parents with children (under 10 years and 15 workers working in the field of active employment policy. Semi-structured interviews with respondents were conducted in the period July-August 2014. Subsequently were analysed in Qualitative Data Analysis Software MAXQDA. Scientific aim of the research was to find out, with such barriers, contributing to long-term unemployment identify unemployed parents with children under 10 years in the transition from parental leave and which problems in reconciling work and family life identify workers working in the field of active employment policy in the Ostrava region. In the first part of article are introduced theoretical frameworks and issue of reconciliation of family and working life in specific phase of life cycle, which is return to the labour market after the end of parental leave. It is pointed out how the demands on the labour market undermine the stability of the family and its reproductive, educational and social care functions. Research has shown, that both groups of respondents identified barriers in low offers part-time jobs, jobs with flexible working hours, difficulties in working time arrangements by employers, problems with availability of kindergartens/nurseries. Parents considered the issue of legitimacy Labour Offices in job searching. The conclusion summarizes the problem formulation and concluding findings.

  10. Synthesis of capillary pressure curves from post-stack seismic data with the use of intelligent estimators: A case study from the Iranian part of the South Pars gas field, Persian Gulf Basin

    Science.gov (United States)

    Golsanami, Naser; Kadkhodaie-Ilkhchi, Ali; Erfani, Amir

    2015-01-01

    Capillary pressure curves are important data for reservoir rock typing, analyzing pore throat distribution, determining height above free water level, and reservoir simulation. Laboratory experiments provide accurate data, however they are expensive, time-consuming and discontinuous through the reservoir intervals. The current study focuses on synthesizing artificial capillary pressure (Pc) curves from seismic attributes with the use of artificial intelligent systems including Artificial Neural Networks (ANNs), Fuzzy logic (FL) and Adaptive Neuro-Fuzzy Inference Systems (ANFISs). The synthetic capillary pressure curves were achieved by estimating pressure values at six mercury saturation points. These points correspond to mercury filled pore volumes of core samples (Hg-saturation) at 5%, 20%, 35%, 65%, 80%, and 90% saturations. To predict the synthetic Pc curve at each saturation point, various FL, ANFIS and ANN models were constructed. The varying neural network models differ in their training algorithm. Based on the performance function, the most accurately functioning models were selected as the final solvers to do the prediction process at each of the above-mentioned mercury saturation points. The constructed models were then tested at six depth points of the studied well which were already unforeseen by the models. The results show that the Fuzzy logic and neuro-fuzzy models were not capable of making reliable estimations, while the predictions from the ANN models were satisfyingly trustworthy. The obtained results showed a good agreement between the laboratory derived and synthetic capillary pressure curves. Finally, a 3D seismic cube was captured for which the required attributes were extracted and the capillary pressure cube was estimated by using the developed models. In the next step, the synthesized Pc cube was compared with the seismic cube and an acceptable correspondence was observed.

  11. In vitro models of the blood-brain barrier

    DEFF Research Database (Denmark)

    Helms, Hans C; Abbott, N Joan; Burek, Malgorzata;

    2016-01-01

    The endothelial cells lining the brain capillaries separate the blood from the brain parenchyma. The endothelial monolayer of the brain capillaries serves both as a crucial interface for exchange of nutrients, gases, and metabolites between blood and brain, and as a barrier for neurotoxic compone...

  12. Gravity-capillary free-surface flows

    CERN Document Server

    Vanden-Broeck, Jean-Marc

    2010-01-01

    Free surface problems occur in many aspects of science and of everyday life such as the waves on a beach, bubbles rising in a glass of champagne, melting ice, pouring flows from a container and sails billowing in the wind. Consequently, the effect of surface tension on gravity-capillary flows continues to be a fertile field of research in applied mathematics and engineering. Concentrating on applications arising from fluid dynamics, Vanden-Broeck draws upon his years of experience in the field to address the many challenges involved in attempting to describe such flows mathematically. Whilst careful numerical techniques are implemented to solve the basic equations, an emphasis is placed upon the reader developing a deep understanding of the structure of the resulting solutions. The author also reviews relevant concepts in fluid mechanics to help readers from other scientific fields who are interested in free boundary problems.

  13. The fate of organic compounds in a cement-based repository: impact on the engineered barrier and the release of C-14 from the near field

    International Nuclear Information System (INIS)

    The degradation of organic materials is taken into account in the safety analysis for a L/ILW (Low- and intermediate-level radioactive waste) repository in Switzerland with the aim of assessing possible impacts on the cement barrier. The waste forms to be disposed of in the planned L/ILW repository will contain HMW polymers and LMW monomeric organic materials. It is anticipated that these organic materials have different degradation rates and therefore different life times in a repository. While the decomposition of LMW organics is expected to be fast and complete during the oxic and early anoxic states of a repository, i.e. before and shortly after repository closure, the decomposition of the HMW polymeric materials is expected to be very slow and, for some materials, to occur over the entire life time of the repository. The degradation of organic materials generates CO2 which gives rise to carbonation of the cement barrier. The maximum acceptable loading of organics in the near field with no detrimental effect on radionuclide immobilization can be estimated on the assumption that at maximum 2/3 of the total portlandite inventory of hydrated cement is allowed to convert to CaCO3 in the case of waste compartments for which the cementitious barrier should remain intact. The maximum loading is determined by the inventory of the organic material under consideration as well as the carbon content and the oxidation state of carbon of the material. Carbon-14 bound in organic compounds is considered to be an important contributor to the annual dose released from a L/ILW repository. While the 14C inventory is well known, the chemical speciation of 14C in the cementitious near field upon liberation in the course of the corrosion of activated steel is only poorly understood. Preliminary corrosion tests with non-activated steel powders show the formation of gaseous and dissolved organic carbon species, e.g. alkanes/alkenes, alcohols, aldehydes, and carboxylic acids, containing

  14. Force Field Analysis Suggests a Lowering of Diffusion Barriers in Atomic Manipulation Due to Presence of STM Tip

    Science.gov (United States)

    Emmrich, Matthias; Schneiderbauer, Maximilian; Huber, Ferdinand; Weymouth, Alfred J.; Okabayashi, Norio; Giessibl, Franz J.

    2015-04-01

    We study the physics of atomic manipulation of CO on a Cu(111) surface by combined scanning tunneling microscopy and atomic force microscopy at liquid helium temperatures. In atomic manipulation, an adsorbed atom or molecule is arranged on the surface using the interaction of the adsorbate with substrate and tip. While previous experiments are consistent with a linear superposition model of tip and substrate forces, we find that the force threshold depends on the force field of the tip. Here, we use carbon monoxide front atom identification (COFI) to characterize the tip's force field. Tips that show COFI profiles with an attractive center can manipulate CO in any direction while tips with a repulsive center can only manipulate in certain directions. The force thresholds are independent of bias voltage in a range from 1 to 10 mV and independent of temperature in a range of 4.5 to 7.5 K.

  15. Force field analysis suggests a lowering of diffusion barriers in atomic manipulation due to presence of STM tip.

    Science.gov (United States)

    Emmrich, Matthias; Schneiderbauer, Maximilian; Huber, Ferdinand; Weymouth, Alfred J; Okabayashi, Norio; Giessibl, Franz J

    2015-04-10

    We study the physics of atomic manipulation of CO on a Cu(111) surface by combined scanning tunneling microscopy and atomic force microscopy at liquid helium temperatures. In atomic manipulation, an adsorbed atom or molecule is arranged on the surface using the interaction of the adsorbate with substrate and tip. While previous experiments are consistent with a linear superposition model of tip and substrate forces, we find that the force threshold depends on the force field of the tip. Here, we use carbon monoxide front atom identification (COFI) to characterize the tip's force field. Tips that show COFI profiles with an attractive center can manipulate CO in any direction while tips with a repulsive center can only manipulate in certain directions. The force thresholds are independent of bias voltage in a range from 1 to 10 mV and independent of temperature in a range of 4.5 to 7.5 K. PMID:25910137

  16. Atom guiding in single mode optical fiber capillary

    Science.gov (United States)

    Romaniuk, Ryszard S.; Dorosz, Jan

    2006-10-01

    A relatively new method of atomic DeBroglie wave transmission in a hollow single mode optical fiber is presented. A slightly blue-detuned, from the atomic resonance, optical evanescent wave in the ring core of the capillary optical fiber creates a potential barrier for co-propagating or counter-propagating DeBroglie wave. The applied optical wavelength, associated with the used atomic transitions, was in the range 1100-400nm. Excited, metastable atoms of chromium, rubidium, cesium, helium, alkalis, etc., were transmitted in the capillary optical fiber. Initially the transmission was multimode and then single mode, with increasing efficiency. There are considered initial application perspectives of this transmission technology of DeBroglie wave for building of coherent cold sources of atoms, atom interferometers, and devices of the inverse lithography, which may possibly compete with the short-wave photo-lithography. The paper is a tutorial and has a teaching and technology review character.

  17. Non-Aqueous Capillary Electrophoresis

    Science.gov (United States)

    Szumski, Michał; Buszewski, Bogusław

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

  18. Identification of chemical warfare agents from vapor samples using a field-portable capillary gas chromatography/membrane-interfaced electron ionization quadrupole mass spectrometry instrument with Tri-Bed concentrator.

    Science.gov (United States)

    Nagashima, Hisayuki; Kondo, Tomohide; Nagoya, Tomoki; Ikeda, Toru; Kurimata, Naoko; Unoke, Shohei; Seto, Yasuo

    2015-08-01

    A field-portable gas chromatograph-mass spectrometer (Hapsite ER system) was evaluated for the detection of chemical warfare agents (CWAs) in the vapor phase. The system consisted of Tri-Bed concentrator gas sampler (trapping time: 3s(-1)min), a nonpolar low thermal-mass capillary gas chromatography column capable of raising temperatures up to 200°C, a hydrophobic membrane-interfaced electron ionization quadrupole mass spectrometer evacuated by a non-evaporative getter pump for data acquisition, and a personal computer for data analysis. Sample vapors containing as little as 22μg sarin (GB), 100μg soman (GD), 210μg tabun (GA), 55μg cyclohexylsarin (GF), 4.8μg sulfur mustard, 390μg nitrogen mustard 1, 140μg of nitrogen mustard 2, 130μg nitrogen mustard 3, 120μg of 2-chloroacetophenone and 990μg of chloropicrin per cubic meter could be confirmed after Tri-Bed micro-concentration (for 1min) and automated AMDIS search within 12min. Using manual deconvolution by background subtraction of neighboring regions on the extracted ion chromatograms, the above-mentioned CWAs could be confirmed at lower concentration levels. The memory effects were also examined and we found that blister agents showed significantly more carry-over than nerve agents. Gasoline vapor was found to interfere with the detection of GB and GD, raising the concentration limits for confirmation in the presence of gasoline by both AMDIS search and manual deconvolution; however, GA and GF were not subject to interference by gasoline. Lewisite 1, and o-chlorobenzylidene malononitrile could also be confirmed by gas chromatography, but it was hard to quantify them. Vapors of phosgene, chlorine, and cyanogen chloride could be confirmed by direct mass spectrometric detection at concentration levels higher than 2, 140, and 10mg/m(3) respectively, by bypassing the micro-concentration trap and gas chromatographic separation. PMID:26118803

  19. Surface tension in microsystems engineering below the capillary length

    CERN Document Server

    Lambert, Pierre

    2013-01-01

    This book describes how surface tension effects can be used by engineers to provide mechanical functions in miniaturized products (<1 mm). Even if precursors of this field such as Jurin or Laplace already date back to the 18th century, describing surface tension effects from a mechanical perspective is very recent.The originality of this book is to consider the effects of capillary bridges on solids, including forces and torques exerted both statically and dynamically by the liquid along the 6 degrees-of-freedom.It provides a comprehensive approach to various applications, such as capillary ad

  20. Pathological features of cerebral cortical capillaries are doubled in Alzheimer's disease and Parkinson's disease

    NARCIS (Netherlands)

    Farkas, E; De Jong, GI; de Vos, RAI; Steur, ENHJ; Luiten, PGM

    2000-01-01

    Cerebral capillaries represent a major interface between the general circulation and the central nervous system and are responsible for sufficient and selective nutrient transport to the brain. Structural damage or dysfunctioning carrier systems of such an active barrier leads to compromised nutrien

  1. The capillary hysteresis model HYSTR: User`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Niemi, A.; Bodvarsson, G.S.

    1991-11-01

    The potential disposal of nuclear waste in the unsaturated zone at Yucca Mountain, Nevada, has generated increased interest in the study of fluid flow through unsaturated media. In the near future, large-scale field tests will be conducted at the Yucca Mountain site, and work is now being done to design and analyze these tests. As part of these efforts a capillary hysteresis model has been developed. A computer program to calculate the hysteretic relationship between capillary pressure {phi} and liquid saturation (S{sub 1}) has been written that is designed to be easily incorporated into any numerical unsaturated flow simulator that computes capillary pressure as a function of liquid saturation. This report gives a detailed description of the model along with information on how it can be interfaced with a transport code. Although the model was developed specifically for calculations related to nuclear waste disposal, it should be applicable to any capillary hysteresis problem for which the secondary and higher order scanning curves can be approximated from the first order scanning curves. HYSTR is a set of subroutines to calculate capillary pressure for a given liquid saturation under hysteretic conditions.

  2. Dynamic capillary wetting studied with dissipative particle dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Cupelli, Claudio; Glatzel, Thomas; Zengerle, Roland; Santer, Mark [Laboratory for MEMS applications, Department of Microsystems Engineering (IMTEK), University of Freiburg, Georges-Koehler-Allee 106, 79110 Freiburg (Germany); Henrich, Bjoern; Moseler, Michael [Freiburg Materials Research Center (FMF), Stefan-Meier-Strasse 21, 79104 Freiburg (Germany)], E-mail: cupelli@imtek.de

    2008-04-15

    We present a study on dynamic capillary wetting in the framework of dissipative particle dynamics (DPD) based on a novel wall model for wetting on solid boundaries. We consider capillary impregnation of a slit pore in two situations: (i) forced (piston-driven) steady state flow and (ii) capillarity driven imbibition out of a finite reservoir. The dynamic contact angle behavior under condition (i) is consistent with the hydrodynamic theories of Cox under partial wetting conditions and Eggers for complete wetting. The flow field near the contact line shows a region of apparent slip flow which provides a natural way of avoiding a stress singularity at the triple line. The dynamics of the capillary imbibition, i.e. condition (ii), is consistently described by the Lucas-Washburn equation augmented by expressions that account for inertia and the influence of the dynamic contact angle.

  3. Barrier mechanisms in the Drosophila blood-brain barrier

    Directory of Open Access Journals (Sweden)

    Samantha Jane Hindle

    2014-12-01

    Full Text Available The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many blood-brain barrier mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the blood-brain barrier can govern whole animal physiologies. This includes novel functions of blood-brain barrier gap junctions in orchestrating synchronized neuroblast proliferation, and of blood-brain barrier secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate blood-brain barrier anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  4. Review of excavation methods and their implications for the near-field barrier of a deep underground repository

    International Nuclear Information System (INIS)

    The report reviews excavation techniques for use in the construction of deep underground radioactive waste repositories, gives a summary of responses of the host rock to excavation and the means of measuring that response and discusses techniques for predicting that response. The review of excavation techniques included technical developments and current practice. To this end an extensive database was developed reviewing major excavations in rock types relevant to disposal and the techniques employed. Creation of an underground opening alters the properties of the rock mass around it. This study identifies stress, displacement, rock mass deformability and permeability as key parameters and reviews how they may be determined. Finally the report discusses the techniques available for predicting the behaviour of the near-field host rock. This concentrates on methods of numerical analysis since existing empirical or analytical methods are not considered suitable. (author)

  5. Investigation into the suitability of capillary tubes for microcrystalline testing.

    Science.gov (United States)

    Elie, Leonie E; Baron, Mark G; Croxton, Ruth S; Elie, Mathieu P

    2013-07-01

    A comparison between microcrystalline tests performed on microscope slides and flat capillary tubes with inner diameters ranging from 0.1 to 0.7 mm was carried out to explore the appropriateness of tubes for rapid testing of suspected drugs of abuse in the laboratory as well as in the field. Tests for mephedrone, cocaine, and phencyclidine were chosen as examples to investigate the handling of the capillary tubes, the influence on crystal habit, size, and the effects on the limit of detection. Image stacking software was used to increase the depth of field of micrographs taken from developed microcrystals greatly enhancing the interpretability even months after carrying out the microcrystalline test. Additionally, the potential of seeding capillary tubes with a reagent was studied. Pre-treatment of tubes would allow microcrystalline tests to be carried out quicker and anywhere without the necessity of taking along expensive and hazardous reagents. The sealing of capillary tubes containing developed microcrystalline tests in order to preserve results for a long period of time was successfully done by applying paraffin wax to the open ends. Finally, it was concluded that capillary tubes are suitable vessels for performing microcrystalline tests. The increased portability of the improved set-up allows tests to be safely executed outside laboratories without impairing the quality of the result. Findings were applied to six legal high samples purchased online between May and August 2011. The active ingredients like MDAI as well as cutting agents like caffeine were successfully identified using the microcrystalline test technique in capillary tubes.

  6. Influence of Surface Passivation on AlN Barrier Stress and Scattering Mechanism in Ultra-thin AlN/GaN Heterostructure Field-Effect Transistors.

    Science.gov (United States)

    Lv, Y J; Song, X B; Wang, Y G; Fang, Y L; Feng, Z H

    2016-12-01

    Ultra-thin AlN/GaN heterostructure field-effect transistors (HFETs) with, and without, SiN passivation were fabricated by the same growth and device processes. Based on the measured DC characteristics, including the capacitance-voltage (C-V) and output current-voltage (I-V) curves, the variation of electron mobility with gate bias was found to be quite different for devices with, and without, SiN passivation. Although the AlN barrier layer is ultra thin (c. 3 nm), it was proved that SiN passivation induces no additional tensile stress and has no significant influence on the piezoelectric polarization of the AlN layer using Hall and Raman measurements. The SiN passivation was found to affect the surface properties, thereby increasing the electron density of the two-dimensional electron gas (2DEG) under the access region. The higher electron density in the access region after SiN passivation enhanced the electrostatic screening for the non-uniform distributed polarization charges, meaning that the polarization Coulomb field scattering has a weaker effect on the electron drift mobility in AlN/GaN-based devices.

  7. Capillary thinning of polymeric filaments

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Szabo, Peter; Hassager, Ole

    1998-01-01

    The capillary thinning of a polymeric filament is analysed experimentally as well as by means of numerical simulation. The experimental procedure is as follows. Initially a liquid sample is kept between two cylindrical plates. Then the bottom plate is lowered under gravity to yield a given strain...

  8. Capillary Rise in a Wedge

    Science.gov (United States)

    Piva, M.

    2009-01-01

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

  9. Influence of local capillary trapping on containment system effectiveness

    Energy Technology Data Exchange (ETDEWEB)

    Bryant, Steven [University Of Texas At Austin, Austin, TX (United States). Center for Petroleum and Geosystems Engineering

    2014-03-31

    Immobilization of CO2 injected into deep subsurface storage reservoirs is a critical component of risk assessment for geologic CO2 storage (GCS). Local capillary trapping (LCT) is a recently established mode of immobilization that arises when CO2 migrates due to buoyancy through heterogeneous storage reservoirs. This project sought to assess the amount and extent of LCT expected in storage formations under a range of injection conditions, and to confirm the persistence of LCT if the seal overlying the reservoir were to lose its integrity. Numerical simulation using commercial reservoir simulation software was conducted to assess the influence of injection. Laboratory experiments, modeling and numerical simulation were conducted to assess the effect of compromised seal integrity. Bench-scale (0.6 m by 0.6 m by 0.03 m) experiments with surrogate fluids provided the first empirical confirmation of the key concepts underlying LCT: accumulation of buoyant nonwetting phase at above residual saturations beneath capillary barriers in a variety of structures, which remains immobile under normal capillary pressure gradients. Immobilization of above-residual saturations is a critical distinction between LCT and the more familiar “residual saturation trapping.” To estimate the possible extent of LCT in a storage reservoir an algorithm was developed to identify all potential local traps, given the spatial distribution of capillary entry pressure in the reservoir. The algorithm assumes that the driving force for CO2 migration can be represented as a single value of “critical capillary entry pressure” Pc,entrycrit, such that cells with capillary entry pressure greater/less than Pc,entrycrit act as barriers/potential traps during CO2 migration. At intermediate values of Pc,entrycrit, the barrier regions become more laterally extensive in the reservoir

  10. Capillary surface discontinuities above reentrant corners

    Science.gov (United States)

    Korevaar, H. J.

    1982-01-01

    A particular configuration of a vertical capillary tube for which S is the equilibrium interface between two fluids in the presence of a downward pointing gravitational field was investigated. S is the graph a function u whose domain is the (horizontal) cross section gamma of the tube. The mean curvature of S is proportional to its height above a fixed reference plane and lambda is a prescribed constant and may be taken between zero and pi/2. Domains gamma for which us is a bounded function but does not extend continuously to d gamma are sought. Simple domains are found and the behavior of u in those domains is studied. An important comparison principle that has been used in the literature to derive many of the results in capillarity is reviewed. It allows one to deduce the approximate shape of a capillary surface by constructing comparison surfaces with mean curvature and contact angle close to those of the (unknown) solution surface. In the context of nonparametric problems the comparison principle leads to height estimates above and below for the function u. An example from the literature where these height estimates have been used successfully is described. The promised domains for which the bounded u does not extend continuously to the boundary are constructed. The point on the boundary at which u has a jump discontinuity will be the vertext of a re-entrant corner having any interior angle theta pi. Using the comparison principle the behavior of u near this point is studied.

  11. Experimental and simulation investigation of ion transfer in different sampling capillaries.

    Science.gov (United States)

    Yu, Quan; Jiang, Tao; Ni, Kai; Qian, Xiang; Tang, Fei; Wang, Xiaohao

    2015-12-01

    Atmospheric pressure interfaces were a fundamental structure for transferring air generated ions into the vacuum manifold of a mass spectrometer. This work is devoted to the characterization of ion transfer in metal capillaries through both experimental and simulated investigations. The impact of capillary configurations on ion transmission efficiency was evaluated using an electrospray mass spectrometer with various bent capillaries as the transfer devices. In addition, a numerical model has been set up by coupling the SIMION 8.0 and the computational flow dynamics for simulation study of ion migration in the complex atmospheric system. The transfer efficiency was found to be highly affected by the variation in electric field and the capillary geometry, revealing that the hydrodynamic and electric force were both dominant and interactional during the transmission process. The consistency of the results from the experimental analysis and simulation modeling proved the validity of the model, which was helpful for understanding ion activity in transfer capillaries. PMID:26634970

  12. A permeable reactive barrier (PRB) media sequence for the remediation of heavy metal and hydrocarbon contaminated water: A field assessment at Casey Station, Antarctica.

    Science.gov (United States)

    Statham, Tom M; Stark, Scott C; Snape, Ian; Stevens, Geoffrey W; Mumford, Kathryn A

    2016-03-01

    A field trial was conducted at Casey Station, Antarctica to assess the suitability of a permeable reactive barrier (PRB) media sequence for the remediation of sites containing both hydrocarbon and heavy metal contamination. An existing PRB was modified to assess a sequence consisting of three sections: (i) Nutrient release/hydrocarbon sorption using ZeoPro™ and granular activated carbon; (ii) Phosphorus and heavy metal capture by granular iron and sand; (iii) Nutrient and excess iron capture by zeolite. The media sequence achieved a greater phosphorus removal capacity than previous Antarctic PRB configurations installed on site. Phosphorus concentrations were reduced during flow through the iron/sand section and iron concentrations were reduced within the zeolite section. However, non-ideal flow was detected during a tracer test and supported by analysis of media and liquid samples from the second summer of operation. Results indicate that the PRB media sequence trialled might be appropriate for other locations, especially less environmentally challenging contaminated sites. PMID:26774301

  13. Hydrologic characterization of the Fry Canyon, Utah site prior to field demonstration of reactive chemical barriers to control radionuclide and trace-element contamination in ground water

    Energy Technology Data Exchange (ETDEWEB)

    Naftz, D.L.; Freethey, G.W. [Geological Survey, Salt Lake City, UT (United States); Davis, J.A. [Geological Survey, Menlo Park, CA (United States)] [and others

    1997-12-31

    The Fry Canyon Site in southeastern Utah has been selected as a long term demonstration site to assess the performance of selected reaction barrier technologies for the removal of uranium and other trace elements from ground water. Objectives include site characterization and evaluation of barrier technologies.

  14. Influence of charge accumulation on a dielectric capillary atmospheric pressure plasma jet

    Science.gov (United States)

    Sands, Brian; Huang, Shih; Speltz, Jared; Niekamp, Matthew; Ganguly, Biswa

    2011-10-01

    Using a single ring electrode configuration and a positive unipolar pulsed voltage source, we examine the influence of the dielectric barrier on the distribution of ionization in a streamer-like dielectric capillary plasma jet utilizing a rare gas flow as a function of anode placement and pulse repetition frequency. At low frequencies, when the anode is recessed at least 5 mm along the capillary, two regions of enhanced ionization can be resolved near the anode and near the capillary tip that are associated with two distinct peaks in the discharge current and locally increased emission intensity in the residual streamer channel. With the anode placed ~20 mm from the capillary tip, the two current peaks were ~13 mA. Increasing the frequency between 6 and 10 kHz, the capillary tip enhancement expanded towards the anode and concentrated there at higher frequencies. The discharge current over this frequency range rose to 18 mA and was increasingly dominated by the earlier peak associated with ionization near the anode. This increased charging of the dielectric surface and reduced the potential available to the ionization front outside the capillary as indicated by a 25% drop in velocity and reduced emission intensity. The surface charging effect is visualized at discharge inception using a Phantom high-frame-rate CCD camera.

  15. Exponential asymptotics and capillary waves

    OpenAIRE

    Chapman, S. J.; Vanden-Broeck, J.

    2002-01-01

    Recently developed techniques in exponential asymptotics beyond all orders are employed on the problem of potential flows with a free surface and small surface tension, in the absence of gravity. Exponentially small capillary waves are found to be generated on the free surface where the equipotentials from singularities in the flow (for example, stagnation points and corners) meet it. The amplitude of these waves is determined, and the implications are considered for many quite general flows....

  16. Capillary electrophoresis in food authenticity.

    Science.gov (United States)

    Kvasnicka, Frantisek

    2005-06-01

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

  17. Inertial Rise in Short Capillaries

    CERN Document Server

    Shardt, Orest; Derksen, J J; Mitra, Sushanta K

    2013-01-01

    In this fluid dynamics video we show capillary rise experiments with diethyl ether in short tubes. The height of each short tube is less than the maximum height the liquid can achieve, and therefore the liquid reaches the top of the tube while still rising. Over a narrow range of heights, the ether bulges out from the top of the tube and spreads onto the external wall.

  18. Capillary Electrophoresis - Optical Detection Systems

    Energy Technology Data Exchange (ETDEWEB)

    Sepaniak, M. J.

    2001-08-06

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

  19. 毛细管超速离心技术在分离混合视野红细胞的应用研究%The applied research of separating red cells with mixed-field by capillary ultracentrifugation technique

    Institute of Scientific and Technical Information of China (English)

    周守容; 刘斌; 梁伟

    2014-01-01

    Objective To analyze the capability of separating red blood cells with mixed field by ultracentrifu-gation technique. Methods Five mL fresh blood of type A was obtained from Shanghai Blood Center blood donors , meanwhile, 5 mL blood of type B was gotten, the preserving time of which was 7 d and 14 d in vitro respectively. All the three samples were washed three times with saline to make packed red blood cells , then added the normal plasma of type A and B, so that all samples were prepared to an appropriate hematocrit of 80%, next, the 3%, 6%of proportion of old cells in fresh A cell were reconstituted to simulate the mixed field artificially. The cell mixing ratio of proximal and distal end was read by comparing with a range of standard ratio after the samples were centrifuged with the speed of 11 000 r/min for 5 min, furthermore, the impact of different of preserving time in vitro on the effect of ultracentrifugation was also observed and all the above mentioned experiments were repeated three times. Results The percentage of B cells for the two samples (3%and 6%) was significantly higher than the initial mixing cell ratio (Z=-2.121, P=0.034) in the distal end, and fresh cells A cells were relocated in the proximal end, it demonstrated that the old and fresh red cells can be separated effectively by the ultracentrifugation technology. In addition , the difference of concentration ratio between 7 d and 14 d cells wasn′t significant(Z=-1.826, P=0.068), the previous percentage of B cells was increased about 1 times by ultracentrifugation. Conclusion The cells with mixed field can be separated effectively using the capillary ultracentr-ifugation technology and should be introduced in the clinical transfusion-related laboratories.%目的:分析毛细管超速离心技术对混合视野红细胞的分离能力。方法取来自上海血液中心献血员的新鲜A型血液5 mL、离体7 d和14 d的陈旧性B型血液各5 mL,分别用0.9%氯化钠注射液洗涤3

  20. Critical Capillary Number of Interfacial Film Displacement in a Capillary Tube

    CERN Document Server

    Yan, Changfei

    2016-01-01

    The role of surface tension and wettability in the dynamics of air-liquid interfaces during immiscible fluid displacement flows in capillary tube driven by pressure has been investigated. The contact angle and capillary number drive the force wetting processes which is controlled by the balance between the capillary and the viscous lubrication forces. The dynamic wetting condition with the critical capillary number is studied analytically and validated experimentally, which demonstrates that the critical capillary number is associated with the contact angle, slip length and capillary radius.

  1. Progression of Diabetic Capillary Occlusion: A Model.

    Directory of Open Access Journals (Sweden)

    Xiao Fu

    2016-06-01

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

  2. Capillary electrophoresis: Imaging of electroosmotic and pressure driven flow profiles in fused silica capillaries

    Science.gov (United States)

    Williams, George O., Jr.

    1996-01-01

    This study is a continuation of the summer of 1994 NASA/ASEE Summer Faculty Fellowship Program. This effort is a portion of the ongoing work by the Biophysics Branch of the Marshall Space Flight Center. The work has focused recently on the separation of macromolecules using capillary electrophoresis (CE). Two primary goals were established for the effort this summer. First, we wanted to use capillary electrophoresis to study the electrohydrodynamics of a sample stream. Secondly, there was a need to develop a methodology for using CE for separation of DNA molecules of various sizes. In order to achieve these goals we needed to establish a procedure for detection of a sample plug under the influence of an electric field Detection of the sample with the microscope and image analysis system would be helpful in studying the electrohydrodynamics of this stream under load. Videotaping this process under the influence of an electric field in real time would also be useful. Imaging and photography of the sample/background electrolyte interface would be vital to this study. Finally, detection and imaging of electroosmotic flow and pressure driven flow must be accomplished.

  3. Numerical Simulation of Particle Distribution in Capillary Membrane during Backwash

    Directory of Open Access Journals (Sweden)

    Anik Keller

    2013-09-01

    Full Text Available The membrane filtration with inside-out dead-end driven UF-/MF- capillary membranes is an effective process for particle removal in water treatment. Its industrial application increased in the last decade exponentially. To date, the research activities in this field were aimed first of all at the analysis of filtration phenomena disregarding the influence of backwash on the operation parameters of filtration plants. However, following the main hypothesis of this paper, backwash has great potential to increase the efficiency of filtration. In this paper, a numerical approach for a detailed study of fluid dynamic processes in capillary membranes during backwash is presented. The effect of particle size and inlet flux on the backwash process are investigated. The evaluation of these data concentrates on the analysis of particle behavior in the cross sectional plane and the appearance of eventually formed particle plugs inside the membrane capillary. Simulations are conducted in dead-end filtration mode and with two configurations. The first configuration includes a particle concentration of 10% homogeneously distributed within the capillary and the second configuration demonstrates a cake layer on the membrane surface with a packing density of 0:6. Analyzing the hydrodynamic forces acting on the particles shows that the lift force plays the main role in defining the particle enrichment areas. The operation parameters contribute in enhancing the lift force and the heterogeneity to anticipate the clogging of the membrane.

  4. Capillary pumped loop body heat exchanger

    Science.gov (United States)

    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.

  5. Stroke and Drug Delivery—In Vitro Models of the Ischemic Blood-Brain Barrier

    DEFF Research Database (Denmark)

    Tornabene, Erica; Brodin, Birger

    2016-01-01

    of permeation pathways across the barrier in ischemic and postischemic brain endothelium is important for development of new medical treatments. The blood-brain barrier, that is, the endothelial monolayer lining the brain capillaries, changes properties during an ischemic event. In vitro models of the blood...

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

    Science.gov (United States)

    Ershov; Zorin; Starov

    1999-08-01

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

  7. Schottky barrier contrasts in single and bi-layer graphene contacts for MoS{sub 2} field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Du, Hyewon; Kim, Taekwang; Shin, Somyeong; Kim, Dahye; Seo, Sunae, E-mail: sunaeseo@sejong.ac.kr [Department of Physics, Sejong University, Seoul 143-747 (Korea, Republic of); Kim, Hakseong; Lee, Sang Wook [Divison of Quantum Phases and Devices, Department of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Sung, Ji Ho; Jo, Moon-Ho [Center for Artificial Low-Dimensional Electronic Systems, Institute for Basic Science (IBS), 77 Cheongam-Ro, Pohang 790-784 (Korea, Republic of); Division of Advanced Materials Science, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang 790-784 (Korea, Republic of); Lee, Myoung Jae [Center for Artificial Low-Dimensional Electronic Systems, Institute for Basic Science (IBS), 77 Cheongam-Ro, Pohang 790-784 (Korea, Republic of); Seo, David H. [Samsung Electronics Company, Limited, System LSI Division, TD Team, Gyunggi 446-711 (Korea, Republic of)

    2015-12-07

    We have investigated single- and bi-layer graphene as source-drain electrodes for n-type MoS{sub 2} transistors. Ti-MoS{sub 2}-graphene heterojunction transistors using both single-layer MoS{sub 2} (1M) and 4-layer MoS{sub 2} (4M) were fabricated in order to compare graphene electrodes with commonly used Ti electrodes. MoS{sub 2}-graphene Schottky barrier provided electron injection efficiency up to 130 times higher in the subthreshold regime when compared with MoS{sub 2}-Ti, which resulted in V{sub DS} polarity dependence of device parameters such as threshold voltage (V{sub TH}) and subthreshold swing (SS). Comparing single-layer graphene (SG) with bi-layer graphene (BG) in 4M devices, SG electrodes exhibited enhanced device performance with higher on/off ratio and increased field-effect mobility (μ{sub FE}) due to more sensitive Fermi level shift by gate voltage. Meanwhile, in the strongly accumulated regime, we observed opposing behavior depending on MoS{sub 2} thickness for both SG and BG contacts. Differential conductance (σ{sub d}) of 1M increases with V{sub DS} irrespective of V{sub DS} polarity, while σ{sub d} of 4M ceases monotonic growth at positive V{sub DS} values transitioning to ohmic-like contact formation. Nevertheless, the low absolute value of σ{sub d} saturation of the 4M-graphene junction demonstrates that graphene electrode could be unfavorable for high current carrying transistors.

  8. Analysis of Small Ions with Capillary Electrophoresis.

    Science.gov (United States)

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

    2016-01-01

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

  9. A New Conductivity Detector for Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new conductivity detector for capillary electrophoresis consisting of an electrochemical cell and a conductive meter was developed. In the cell, the microelectrode and capillary were inserted through the cell wall and fixed by screws and sealing ring, the ends of microelectrode and capillary were located by a guide with two cross holes. LOD for K+ was 1.5×10-5 mol/L.

  10. Serum proteins analysis by capillary electrophoresis

    OpenAIRE

    Uji, Yoshinori; Okabe, Hiroaki

    2001-01-01

    The purpose of this study was to evaluate the efficacy of multi-capillary electrophoresis instrument in clinical laboratory. An automated clinical capillary electrophoresis system was evaluated for performing serum proteins electrophoresis and immuno-fixation electrophoresis by subtraction. In this study the performance of capillary electrophoresis was compared with the cellulose acetate membrane electrophoresis and agarose gel immunofixation electrophoresis for serum proteins. The results of...

  11. Slope wavenumber spectrum models of capillary and capillary-gravity waves

    Institute of Scientific and Technical Information of China (English)

    贾永君; 张杰; 王岩峰

    2010-01-01

    Capillary and capillary-gravity waves possess a random character, and the slope wavenumber spectra of them can be used to represent mean distributions of wave energy with respect to spatial scale of variability. But simple and practical models of the slope wavenumber spectra have not been put forward so far. In this article, we address the accurate definition of the slope wavenumber spectra of water surface capillary and capillary-gravity waves. By combining the existing slope wavenumber models and using th...

  12. Capillary thinning of polymeric filaments

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Szabo, Peter

    1999-01-01

    The capillary thinning of filaments of a Newtonian polybutene fluid and a viscoelastic polyisobutylene solution are analyzed experimentally and by means of numerical simulation. The experimental procedure is as follows. Initially, a liquid sample is placed between two cylindrical plates. Then......, the bottom plate is lowered under gravity to produce a specified strain. The sample is thereby stretched into a filament. Provided the filament is sufficiently long, surface tension will induce a thinning of the filament until breakup in finite time. The numerical simulations are performed with a Lagrangian...

  13. Electromigration dispersion in Capillary Electrophoresis

    CERN Document Server

    Chen, Zhen; 10.1007/s11538-011-9708-7

    2012-01-01

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

  14. Capillary electrophoresis theory and practice

    CERN Document Server

    Grossman, Paul D

    1992-01-01

    This book is designed to be a practical guide, used by wide audience, including those new to CE, those more experienced, routine users, those interested in technology development, and those involved with applications research. References have been emphasized to allow the reader to explore the detailed specifics and theoretical foundations.This book draws together the rapidly evolving, diverse, and multidisciplinary subject of capillary electrophoresis (CE). It is designed as a practical guide to be used by a wide audience, including those new to CE as well as more experienced users. T

  15. Atomic Force Controlled Capillary Electrophoresis

    Science.gov (United States)

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

    2010-03-01

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

  16. High-Throughput Proteomics Using High Efficiency Multiple-Capillary Liquid Chromatography With On-Line High-Performance ESI FTICR Mass Spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yufeng (BATTELLE (PACIFIC NW LAB)); Tolic, Nikola (BATTELLE (PACIFIC NW LAB)); Zhao, Rui (ASSOC WESTERN UNIVERSITY); Pasa Tolic, Ljiljana (BATTELLE (PACIFIC NW LAB)); Li, Lingjun (Illinois Univ Of-Urbana/Champa); Berger, Scott J.(ASSOC WESTERN UNIVERSITY); Harkewicz, Richard (BATTELLE (PACIFIC NW LAB)); Anderson, Gordon A.(BATTELLE (PACIFIC NW LAB)); Belov, Mikhail E.(BATTELLE (PACIFIC NW LAB)); Smith, Richard D.(BATTELLE (PACIFIC NW LAB))

    2000-12-01

    We report on the design and application of a high-efficiency multiple-capillary liquid chromatography (LC) system for high-throughput proteome analysis. The multiple-capillary LC system was operated at the pressure of 10,000 psi using commercial LC pumps to deliver the mobile phase and newly developed passive feedback valves to switch the mobile phase flow and introduce samples. The multiple-capillary LC system was composed of several serially connected dual-capillary column devices. The dual-capillary column approach was designed to eliminate the time delay for regeneration (or equilibrium) of the capillary column after its use under the mobile phase gradient condition (i.e. one capillary column was used in separation and the other was washed using mobile phase A). The serially connected dual-capillary columns and ESI sources were operated independently, and could be used for either''backup'' operation or with other mass spectrometer(s). This high-efficiency multiple-capillary LC system uses switching valves for all operations and is highly amenable to automation. The separations efficiency of dual-capillary column device, optimal capillary dimensions (column length and packed particle size), suitable mobile phases for electrospray, and the capillary re-generation were investigated. A high magnetic field (11.5 tesla) Fourier transform ion cyclotron resonance (FTICR) mass spectrometer was coupled on-line with this high-efficiency multiple-capillary LC system through an electrospray ionization source. The capillary LC provided a peak capacity of {approx}600, and the 2-D capillary LC-FTICR provided a combined resolving power of > 6 x 10 7 polypeptide isotopic distributions. For yeast cellular tryptic digests, > 100,000 polypeptides were typically detected, and {approx}1,000 proteins can be characterized in a single run.

  17. High lung volume increases stress failure in pulmonary capillaries

    Science.gov (United States)

    Fu, Z.; Costello, M. L.; Tsukimoto, K.; Prediletto, R.; Elliott, A. R.; Mathieu-Costello, O.; West, J. B.

    1992-01-01

    We previously showed that when pulmonary capillaries in anesthetized rabbits are exposed to a transmural pressure (Ptm) of approximately 40 mmHg, stress failure of the walls occurs with disruption of the capillary endothelium, alveolar epithelium, or sometimes all layers. The present study was designed to test whether stress failure occurred more frequently at high than at low lung volumes for the same Ptm. Lungs of anesthetized rabbits were inflated to a transpulmonary pressure of 20 cmH2O, perfused with autologous blood at 32.5 or 2.5 cmH2O Ptm, and fixed by intravascular perfusion. Samples were examined by both transmission and scanning electron microscopy. The results were compared with those of a previous study in which the lung was inflated to a transpulmonary pressure of 5 cmH2O. There was a large increase in the frequency of stress failure of the capillary walls at the higher lung volume. For example, at 32.5 cmH2O Ptm, the number of endothelial breaks per millimeter cell lining was 7.1 +/- 2.2 at the high lung volume compared with 0.7 +/- 0.4 at the low lung volume. The corresponding values for epithelium were 8.5 +/- 1.6 and 0.9 +/- 0.6. Both differences were significant (P less than 0.05). At 52.5 cmH2O Ptm, the results for endothelium were 20.7 +/- 7.6 (high volume) and 7.1 +/- 2.1 (low volume), and the corresponding results for epithelium were 32.8 +/- 11.9 and 11.4 +/- 3.7. At 32.5 cmH2O Ptm, the thickness of the blood-gas barrier was greater at the higher lung volume, consistent with the development of more interstitial edema. Ballooning of the epithelium caused by accumulation of edema fluid between the epithelial cell and its basement membrane was seen at 32.5 and 52.5 cmH2O Ptm. At high lung volume, the breaks tended to be narrower and fewer were oriented perpendicular to the axis of the pulmonary capillaries than at low lung volumes. Transmission and scanning electron microscopy measurements agreed well. Our findings provide a physiological

  18. Diagnostics of a high current capillary discharge

    International Nuclear Information System (INIS)

    We have demonstrated that thin (10 to 25 μm diameter) capillaries can be fabricated in suitably configured insulators for use in pulse power machines. Large currents can be used to heat these capillaries which produce photons with an energies greater than 1 keV

  19. Pulmonary capillary haemangiomatosis in a premature infant

    International Nuclear Information System (INIS)

    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  20. Pulmonary capillary haemangiomatosis in a premature infant

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cicero J.T.A.; Massie, John; Mandelstam, Simone A. [University of Melbourne, Royal Children' s Hospital, Parkville, VIC (Australia)

    2005-06-01

    Pulmonary capillary haemangiomatosis (PCH) is a rare disorder characterized by widespread capillary proliferation in the lung, infiltrating the interstitium and the alveolar walls. We present the HRCT features of PCH in a surviving ex-premature infant. To our knowledge, this is a unique case of the radiological features of PCH in a young living infant. (orig.)

  1. Sheathless interface for coupling capillary electrophoresis with mass spectrometry

    Science.gov (United States)

    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.

  2. Reactive geothermal transport simulation to study the formation mechanism of impermeable barrier between acidic and neutral fluid zones in the Onikobe Geothermal Field, Japan

    Energy Technology Data Exchange (ETDEWEB)

    Todaka, Norifumi; Akasaka, Chitosi; Xu, Tianfu; Pruess, Karsten

    2003-04-09

    Two types of fluids are encountered in the Onikobe geothermal reservoir, one is neutral and the other is acidic (pH=3). It is hypothesized that acidic fluid might be upwelling along a fault zone and that an impermeable barrier might be present between the acidic and neutral fluid zones. We carried out reactive geothermal transport simulations using TOUGHREACT (Xu and Pruess, 1998 and 2001) to test such a conceptual model. Mn-rich smectite precipitated near the mixing front and is likely to form an impermeable barrier between regions with acidic and neutral fluids.

  3. Spectroscopic Approach to Capillary-Alveolar Membrane Damage Induced Acute Lung Injury

    Directory of Open Access Journals (Sweden)

    Jing Wang

    1999-01-01

    Full Text Available BACKGROUND: Acute (or adult respiratory distress syndrome (ARDS is often associated with a high mortality rate in the critical care population. The term acute lung injury (ALI, a primitive phase of ARDS, was introduced by the European and American consensus groups to provide early diagnoses of ARDS. The pathophysiological characterization of ALI/ARDS – an increased pulmonary capillary-alveolar membrane barrier permeability – is generally not included in current intensive care unit diagnosis criteria.

  4. Controlled capillary assembly of magnetic Janus particles at fluid-fluid interfaces.

    Science.gov (United States)

    Xie, Qingguang; Davies, Gary B; Harting, Jens

    2016-08-21

    Capillary interactions can be used to direct assembly of particles adsorbed at fluid-fluid interfaces. Precisely controlling the magnitude and direction of capillary interactions to assemble particles into favoured structures for materials science purposes is desirable but challenging. In this paper, we investigate capillary interactions between magnetic Janus particles adsorbed at fluid-fluid interfaces. We develop a pair-interaction model that predicts that these particles should arrange into a side-side configuration, and carry out simulations that confirm the predictions of our model. Finally, we investigate the monolayer structures that form when many magnetic Janus particles adsorb at the interface. We find that the particles arrange into long, straight chains exhibiting little curvature, in contrast with capillary interactions between ellipsoidal particles. We further find a regime in which highly ordered, lattice-like monolayer structures form, which can be tuned dynamically using an external magnetic field.

  5. A capillary viscometer designed for the characterization of biocompatible ferrofluids

    Science.gov (United States)

    Nowak, J.; Odenbach, S.

    2016-08-01

    Suspensions of magnetic nanoparticles are receiving a growing interest in biomedical research. These ferrofluids can, e.g., be used for the treatment of cancer, making use of the drug targeting principle or using an artificially induced heating. To enable a safe application the basic properties of the ferrofluids have to be well understood, including the viscosity of the fluids if an external magnetic field is applied. It is well known that the viscosity of ferrofluids rises if a magnetic field is applied, where the rise depends on shear rate and magnetic field strength. In case of biocompatible ferrofluids such investigations proved to be rather complicated as the experimental setup should be close to the actual application to allow justified predictions of the effects which have to be expected. Thus a capillary viscometer, providing a flow situation comparable to the flow in a blood vessel, has been designed. The glass capillary is exchangeable and different inner diameters can be used. The range of the shear rates has been adapted to the range found in the human organism. The application of an external magnetic field is enabled with two different coil setups covering the ranges of magnetic field strengths required on the one hand for a theoretical understanding of particle interaction and resulting changes in viscosity and on the other hand for values necessary for a potential biomedical application. The results show that the newly designed capillary viscometer is suitable to measure the magnetoviscous effect in biocompatible ferrofluids and that the results appear to be consistent with data measured with rotational rheometry. In addition, a strong change of the flow behaviour of a biocompatible ferrofluid was proven for ranges of the shear rate and the magnetic field strength expected for a potential biomedical application.

  6. Influence of the Thickness of the Barrier Layer in Nanoheterostructures and the Gate-Drain Capacitance on the Microwave and Noise Parameters of Field-Effect AlGaN/GaN HEMT

    Science.gov (United States)

    Mikhaylovich, S. V.; Fedorov, Yu. V.

    2016-07-01

    We perform a computational and analytical study of how the thickness of the barrier layer in nanoheterostructures and the gate-drain capacitance C gd influence the microwave parameters (limiting frequency of current amplification and maximum generation frequency) and noise parameters (noise factor) of a field-effect AlGaN/GaN high electron mobility transistor. The results of complex measurements of the parameters of such transistors based on nanoheterostructures with a barrier layer thickness of 3.5-15.7 nm, which were performed within the framework of four technological routes in the range 0.1-67 GHz, are presented. It is shown that in order to reduce the noise ratio and improve the microwave parameters, it is necessary to optimize both the parameters of nanoheterostructures and the manufacturing techniques. In particular, the thickness of the barrier layer should be reduced, and the gate length should be chosen such as to maximize the product of the squared maximum current amplification frequency in the interior of the transistor and the output impedance between the drain and the source. Additionally, attention should be given to the shape of the gate to reduce the capacitance C gd. Under certain conditions of manufacture of nitride field-effect HEMT, one can achieve a lower noise factor compared with the transistors based on arsenide nanoheterostructures.

  7. Diagnostics of atmospheric pressure capillary DBD oxygen plasma jet

    CERN Document Server

    Roy, N C; Pramanik, B K

    2015-01-01

    Atmospheric pressure capillary dielectric barrier oxygen discharge plasma jet is developed to generate non-thermal plasma using unipolar positive pulse power supply. Both optical and electrical techniques are used to investigate the characteristics of the produced plasma as function of applied voltage and gas flow rate. Analytical results obtained from the optical emission spectroscopic data reveal the gas temperature, rotational temperature, excitation temperature and electron density. Gas temperature and rotational temperature are found to decrease with increasing oxygen flow rate but increase linearly with applied voltage. It is exposed that the electron density is boosting up with enhanced applied voltage and oxygen flow rate, while the electron excitation temperature is reducing with rising oxygen flow rate. Electrical characterization demonstrates that the discharge frequency is falling with flow rate but increasing with voltage. The produced plasma is applied preliminarily to study the inactivation yie...

  8. Multilayer coatings for flexible high-barrier materials

    Science.gov (United States)

    Vaško, Karol; Noller, Klaus; Mikula, Milan; Amberg-Schwab, Sabine; Weber, Ulrike

    2009-06-01

    A multilayer, flexible, and transparent high-barrier system based on flexible plastic foils, polyethyleneterephthalate (PET) and ethylene-tetrafluoroethylene-copolymer (ETFE), combined with vacuum-deposited, inorganic SiOx layers and hybrid ORMOCER® varnish layers were prepared in different orders on a semiproduction level. Barrier properties of prepared systems, as water vapour transmission (WVTR) and oxygen transmission (OTR), were measured and studied in connection with surface energy, surface topography, and water vapour adsorption properties. Correlations among layers sequence, barrier properties, and other parameters are presented, including some basic principles of permeation of substances through multilayer barrier systems. A combination of several inorganic and hybrid varnish layers is necessary to achieve the technological demands from a barrier standpoint. It is easier to suppress the oxygen transport than the water transport, due to the additional active penetration of water through hydrogen bonds and silanol creations at oxide interfaces, capillary condensation, and swelling with high internal pressure, leading to new defects.

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

    Science.gov (United States)

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

    2016-09-01

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

  10. Analytical characterization of wine and its precursors by capillary electrophoresis.

    Science.gov (United States)

    Gomez, Federico J V; Monasterio, Romina P; Vargas, Verónica Carolina Soto; Silva, María F

    2012-08-01

    The accurate determination of marker chemical species in grape, musts, and wines presents a unique analytical challenge with high impact on diverse areas of knowledge such as health, plant physiology, and economy. Capillary electromigration techniques have emerged as a powerful tool, allowing the separation and identification of highly polar compounds that cannot be easily separated by traditional HPLC methods, providing complementary information and permitting the simultaneous analysis of analytes with different nature in a single run. The main advantage of CE over traditional methods for wine analysis is that in most cases samples require no treatment other than filtration. The purpose of this article is to present a revision on capillary electromigration methods applied to the analysis of wine and its precursors over the last decade. The current state of the art of the topic is evaluated, with special emphasis on the natural compounds that have allowed wine to be considered as a functional food. The most representative revised compounds are phenolic compounds, amino acids, proteins, elemental species, mycotoxins, and organic acids. Finally, a discussion on future trends of the role of capillary electrophoresis in the field of analytical characterization of wines for routine analysis, wine classification, as well as multidisciplinary aspects of the so-called "from soil to glass" chain is presented.

  11. Nanoparticle-based capillary electroseparation of proteins in polymer capillaries under physiological conditions

    DEFF Research Database (Denmark)

    Nilsson, C.; Harwigsson, I.; Becker, K.;

    2010-01-01

    Totally porous lipid-based liquid crystalline nanoparticles were used as pseudostationary phase for capillary electroseparation with LIF detection of proteins at physiological conditions using unmodified cyclic olefin copolymer capillaries (Topas (R), 6.7 cm effective length). In the absence of n...... at protein friendly conditions. The developed capillary-based method facilitates future electrochromatography of proteins on polymer-based microchips under physiological conditions and enables the initial optimization of separation conditions in parallel to the chip development....

  12. Capillary electrochromatography using fibers as stationary phases.

    Science.gov (United States)

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

    2001-10-01

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

  13. Capillary detectors for high resolution tracking

    CERN Document Server

    Annis, P

    1997-01-01

    We present a new tracking device based on glass capillary bundles or layers filled with highly purified liquid scintillator and read out at one end by means of image intensifiers and CCD devices. A large-volume prototype consisting of 5 × 105 capillaries with a diameter of 20 μm and a length of 180 cm and read out by a megapixel CCD has been tested with muon and neutrino beams at CERN. With this prototype a two track resolution of 33 μm was achieved with passing through muons. Images of neutrino interactions in a capillary bundle have also been acquired and analysed. Read-out chains based on Electron Bombarded CCD (EBCCD) and image pipeline devices are also investigated. Preliminary results obtained with a capillary bundle read out by an EBCCD are presented.

  14. Capillary electrochromatography using fibers as stationary phases.

    Science.gov (United States)

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

    2001-10-01

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

  15. Capillary Optics generate stronger X-rays

    Science.gov (United States)

    1996-01-01

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

  16. Ultrastructural studies on the barrier properties of the paraganglia in the rat recurrent laryngeal nerve.

    Science.gov (United States)

    Chien, C L; Chau, Y P; Lu, K S

    1991-01-01

    The permeability of blood capillaries in the paraganglia of the rat recurrent laryngeal nerve (RLN) was investigated by employing the ionic lanthanum tracer at ultrastructural level. Two types of blood capillaries, namely, fenestrated and nonfenestrated types, were observed in the rat RLN and its associated paraganglia (RLN paraganglia). A preferential distribution of fenestrated capillaries in the RLN paraganglia was noted. Nonfenestrated capillaries were distributed in the area of RLN devoid of paraganglia. Minute aberrant ganglia consisting of 4-8 neurons were frequently encountered in the rat RLN near the paraganglia. The capillaries in these neuronal areas were also nonfenestrated. The lanthanum tracer was limited within the vascular lumen, but not in the extravascular space, in the RLN proper and in the area of RLN paraganglia where the neurons were identified. In the RLN paraganglia, the tracer was located in the vascular lumen, extravascular space, periaxonal space of nerve fibers, and the intercellular space of the RLN paraganglionic cells. We concluded that (1) a blood-nerve barrier and a blood-ganglion (or blood-neuron) barrier exist in the area of RLN devoid of paraganglia, and (2) blood-paraganglion barrier and blood-nerve barrier were lacking in the rat RLN paraganglia.

  17. Selectivity and detection in capillary electrophoresis

    OpenAIRE

    Khaled, Maha Yehia

    1994-01-01

    This work is a contribution to the minimization of some of the selectivity and detection limitations in capillary electrophoresis. A more practical design of an electrochemical detector is introduced with simultaneous on-line UV detection (1), for the selective detection of a number of pungent and neurological compounds, the piperines and the capsacinoids. Commercially available microelectrodes together with large 25 μm id fused silica capillary columns are used for the fir...

  18. Capillary fracture of soft gels

    Science.gov (United States)

    Bostwick, Joshua B.; Daniels, Karen E.

    2013-10-01

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

  19. Cell adhesion during bullet motion in capillaries.

    Science.gov (United States)

    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.

  20. Simulation of ion guiding through insulating capillaries: effects of intercapillary interaction

    International Nuclear Information System (INIS)

    Complete text of publication follows. Nanocapillaries through insulating foils have received interest as a target for beams of slow highly-charged ions. Transmission of projectiles in their initial charge state have been measured for angles of incidence larger than the geometrical opening angle. Ions are guided along the capillary axis and do not closely interact with the inner walls of the capillary. We have developed a classical trajectory transport theory of this self-organized guiding process that relates the microscopic charge-up with macroscopic material properties and includes multi-capillary effects on a phenomenological level. In this work simulations for ion guiding through insulating nanocapillaries within the framework of a mean-field classical transport theory are presented. We combine a microscopic trajectory simulation with macroscopic material properties for bulk an surface conductivities of highly insulating materials. Projectiles hitting the inner wall of the insulating material in the early stage of the irradiation deposit their charge on the capillary surface. These charges diffuse along the surface and, eventually, into the bulk due to the small but finite surface and bulk conductivities of the insulator. Projectiles entering the capillary at a later stage are deflected by the Coulomb field of a self-organized charge patch close to the entrance of the capillary. Invoking this scenario we are able to reproduce a range of experimental findings, e.g. ion guiding even for large incidence angles. We have shown that these results can be interpreted on the basis of a linear model including transport of deposited charges along the surface without resorting to freely adjustable parameters. Approximate inclusion of multi-capillary effects [1] further improve the microscopic simulation and show the same qualitative dependence on ion energy or angle of incidence as the experiment (see Fig. 1). (author)

  1. Recent advances in the preparation and application of monolithic capillary columns in separation science.

    Science.gov (United States)

    Hong, Tingting; Yang, Xi; Xu, Yujing; Ji, Yibing

    2016-08-10

    Novel column technologies involving various materials and efficient reactions have been investigated for the fabrication of monolithic capillary columns in the field of analytical chemistry. In addition to the development of these miniaturized systems, a variety of microscale separation applications have achieved noteworthy results, providing a stepping stone for new types of chromatographic columns with improved efficiency and selectivity. Three novel strategies for the preparation of capillary monoliths, including ionic liquid-based approaches, nanoparticle-based approaches and "click chemistry", are highlighted in this review. Furthermore, we present the employment of state-of-the-art capillary monolithic stationary phases for enantioseparation, solid-phase microextraction, mixed-mode separation and immobilized enzyme reactors. The review concludes with recommendations for future studies and improvements in this field of research. PMID:27282747

  2. Capillary fracture of soft gels.

    Science.gov (United States)

    Bostwick, Joshua B; Daniels, Karen E

    2013-10-01

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

  3. Economic alternatives for containment barriers

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, P.J.; Jasperse, B.H.; Fisher, M.J. [Geo-Con, Inc., Monroeville, PA (United States)

    1997-12-31

    Fixation, barriers, and containment of existing landfills and other disposal areas are often performed by insitu auger type soil mixing and jet grouting. Cement or other chemical reagents are mixed with soil to form both vertical and horizontal barriers. Immobilization of contaminants can be economically achieved by mixing soil and the contaminants with reagents that solidify or stabilize the contaminated area. Developed in Japan, and relatively new to the United States, the first large scale application was for a vertical barrier at the Jackson Lake Dam project in 1986. This technology has grown in both the civil and environmental field since. The paper describes current United States practice for Deep Soil Mixing (over 12 meters in depth), and Shallow Soil Mixing for vertical barriers and stabilization/solidification, and Jet Grouting for horizontal and vertical barriers. Creating very low permeability barriers at depth with minimal surface return often makes these techniques economical when compared to slurry trenches. The paper will discuss equipment, materials, soil and strength parameters, and quality control.

  4. A Novel Polybrene/Chondroitin Sulfate C Double Coated Capillary and Its Application in Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    DU,Ying-Xiang(杜迎翔); HONDA,Susumu; TAGA,Atsushi; LIU,Wen-Ying(刘文英); SUZUKI,Shigeo

    2002-01-01

    A new capillary coated by double polymer, polybrene/chondroitin sulfate C (P/CC), was developed using a simple procedure. The P/CC double coated capillary showed long lifetime,strong chemical stability and good reproducibility. It endured during more than 100 replicated analyses and was also tolerant to HCl (1 mol/L), NaOH (0.01 mol/L), CH3OH and CH3CN. The P/CC double coated capillary can be applied to basic drug analyses. The adsorption of basic drugs to the capillary wall was suppressed and the peak tailing greatly decreased. The use of the P/CC double coated capillary allowed excelent separation of the enantiomers of some basic drugs by using chondroitin sulfate C as the chiral selector, ami the peak symmetry of basic drugs was further improved under these conditions.

  5. Capillary-Tube Model and Experiment of Multiphase Flow in Capillary Fringes

    Institute of Scientific and Technical Information of China (English)

    武晓峰; 唐杰; 吕贤弼

    2002-01-01

    Contamination of soil and groundwater by organic substances is causing more and more problems worldwide. Analysis of the movement and distribution of nonaqueous phase liquids (NAPLs) in subsurface domain is critical for contaminant remediation. Two-dimensional experiments were conducted in a transparent plexiglass trough (105.0 cm×70.0 cm×1.5 cm) to simulate the release and redistribution of gasoline and kerosene in porous media. The results show that before the contaminant distribution reaches equilibrium, the movement of light NAPLs (LNAPLs) can be divided into four sub-stages. After the contaminant front reaches the upper boundary of the capillary fringe, contaminant movement along the upper boundary of the capillary fringe is the primary transport process. Most of the contaminants then move into the capillary fringe except for the residual part. One-dimensional and two-dimensional capillary tube models were developed to analyze the movement of LNAPLs in the capillary fringe.

  6. Evaluation of the thermal resistance of a roof-mounted multi-reflective radiant barrier for tropical and humid conditions: Experimental study from field measurements

    CERN Document Server

    Miranville, Frédéric; Guichard, Stéphane; Boyer, Harry; Praene, Jean Philippe; Bigot, Dimitri

    2012-01-01

    This paper deals with the experimental evaluation of a roof-mounted multi-reflective radiant barrier (MRRB), installed according to the state of the art, on a dedicated test cell. An existing experimental device was completed with a specific system for the regulation of the airflow rate in the upper air layer included in a typical roof from Reunion Island. Several experimental sequences were conducted to determine the thermal resistance of the roof according to several parameters and following a specific method. The mean method, well known in international standards (ISO 9869 - 1994) for the determination of the thermal resistance using dynamic data, was used. The method was implemented in a building simulation code in order to allow the determination of the thermal indicator automatically. Experimental results are proposed according to different seasonal periods and for different values of the airflow rate in the upper air layer

  7. Synthetic Capillaries to Control Microscopic Blood Flow

    Science.gov (United States)

    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.

  8. EUV radiation from nitrogen capillary discharge

    Science.gov (United States)

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

    2014-08-01

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

  9. Fluid trapping during capillary displacement in fractures

    Science.gov (United States)

    Yang, Zhibing; Neuweiler, Insa; Méheust, Yves; Fagerlund, Fritjof; Niemi, Auli

    2016-09-01

    The spatial distribution of fluid phases and the geometry of fluid-fluid interfaces resulting from immiscible displacement in fractures cast decisive influence on a range of macroscopic flow parameters. Most importantly, these are the relative permeabilities of the fluids as well as the macroscopic irreducible saturations. They also influence parameters for component (solute) transport, as it usually occurs through one of the fluid phase only. Here, we present a numerical investigation on the critical role of aperture variation and spatial correlation on fluid trapping and the morphology of fluid phase distributions in a geological fracture. We consider drainage in the capillary dominated regime. The correlation scale, that is, the scale over which the two facing fracture walls are matched, varies among the investigated geometries between L/256 and L (self-affine fields), L being the domain/fracture length. The aperture variability is quantified by the coefficient of variation (δ), ranging among the various geometries from 0.05 to 0.25. We use an invasion percolation based model which has been shown to properly reproduce displacement patterns observed in previous experiments. We present a quantitative analysis of the size distribution of trapped fluid clusters. We show that when the in-plane curvature is considered, the amount of trapped fluid mass first increases with increasing correlation scale Lc and then decreases as Lc further increases from some intermediate scale towards the domain length scale L. The in-plane curvature contributes to smoothening the invasion front and to dampening the entrapment of fluid clusters of a certain size range that depends on the combination of random aperture standard deviation and spatial correlation.

  10. Capillary rise of water in hydrophilic nanopores

    CERN Document Server

    Gruener, Simon; Wallacher, Dirk; Kityk, Andriy V; Huber, Patrick; 10.1103/PhysRevE.79.067301

    2009-01-01

    We report on the capillary rise of water in three-dimensional networks of hydrophilic silica pores with 3.5nm and 5nm mean radii, respectively (porous Vycor monoliths). We find classical square root of time Lucas-Washburn laws for the imbibition dynamics over the entire capillary rise times of up to 16h investigated. Provided we assume two preadsorbed strongly bound layers of water molecules resting at the silica walls, which corresponds to a negative velocity slip length of -0.5nm for water flow in silica nanopores, we can describe the filling process by a retained fluidity and capillarity of water in the pore center. This anticipated partitioning in two dynamic components reflects the structural-thermodynamic partitioning in strongly silica bound water layers and capillary condensed water in the pore center which is documented by sorption isotherm measurements.

  11. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Y.

    1994-07-27

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

  12. Vortex-Kink Interaction and Capillary Waves in a Vector Superfluid

    CERN Document Server

    Nepomnyashchy, A A

    1996-01-01

    Interaction of a vortex in a circularly polarized superfluid component of a 2d complex vector field with the phase boundary between superfluid phases with opposite signs of polarization leads to a resonant excitation of a ``capillary'' wave on the boundary. This leads to energy losses by the vortex--image pair that has to cause its eventual annihilation.

  13. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-05-06

    Various methods and systems are provided for smart parking barriers. In one example, among others, a smart parking barrier system includes a movable parking barrier located at one end of a parking space, a barrier drive configured to control positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking space and a second position that allows access to the parking space. The parking controller can initiate movement of the movable parking barrier in response to a positive identification of an individual allowed to use the parking space. The parking controller can identify the individual through, e.g., a RFID tag, a mobile device (e.g., a remote control, smartphone, tablet, etc.), an access card, biometric information, or other appropriate identifier.

  14. High-current carbon-epoxy capillary cathode

    Science.gov (United States)

    Gleizer, J. Z.; Queller, T.; Bliokh, Yu.; Yatom, S.; Vekselman, V.; Krasik, Ya. E.; Bernshtam, V.

    2012-07-01

    The results of experiments on the reproducible generation of an electron beam having a high current density of up to 300 A/cm2 and a satisfactorily uniform cross-sectional distribution of current density in a ˜200 kV, ˜450 ns vacuum diode with a carbon-epoxy capillary cathode are presented. It was found that the source of the electrons is the plasma formed as a result of flashover inside the capillaries. It is shown that the plasma formation occurs at an electric field ≤15 kV/cm and that the cathode sustains thousands of pulses without degradation in its emission properties. Time- and space-resolved visible light observation and spectroscopy analyses were used to determine the cathode plasma's density, temperature, and expansion velocity. It was found that the density of the cathode plasma decreases rapidly in relation to the distance from the cathode. In addition, it was found that the main reason for the short-circuiting of the accelerating gap is the formation and expansion of the anode plasma. Finally, it was shown that when an external guiding magnetic field is present, the injection of the electron beam into the drift space with a current amplitude exceeding its critical value changes the radial distribution of the current density of the electron beam because the inner electrons are reflected from the virtual cathode.

  15. High resolution mosaic image of capillaries in human retina by adaptive optics

    Institute of Scientific and Technical Information of China (English)

    Ning Ling; Yudong Zhang; Xuejun Rao; Cheng Wang; Yiyun Hu; Wenhan Jiang

    2005-01-01

    Adaptive optics (AO) has been proved as a powerful means for high resolution imaging of human retina.Because of the pixel number of charge-coupled device (CCD) camera, the field of view is limited to 1°.In order to have image of capillaries around vivo human fovea, we use mosaic method to obtain high resolution image in area of 6°× 6°. Detailed structures of capillaries around fovea with resolution of 2.3μm are clearly shown. Comparison shows that this method has a much higher resolution than current clinic retina imaging methods.

  16. Capillary Rise of Liquids in Nanopores

    CERN Document Server

    Huber, Patrick; Kityk, Andriy V

    2006-01-01

    We present measurements on the spontaneous imbibition (capillary rise) of water, a linear hydrocarbon (n-C16H34) and a liquid crystal (8OCB) into the pore space of monolithic, nanoporous Vycor glass (mean pore radius 5 nm). Measurements on the mass uptake of the porous hosts as a function of time, m(t), are in good agreement with the Lucas-Washburn square root of time prediction, typical of imbibition of liquids into porous hosts. The relative capillary rise velocities scale as expected from the bulk fluid parameters.

  17. Microfluidic chip-capillary electrophoresis devices

    CERN Document Server

    Fung, Ying Sing; Du, Fuying; Guo, Wenpeng; Ma, Tongmei; Nie, Zhou; Sun, Hui; Wu, Ruige; Zhao, Wenfeng

    2015-01-01

    Capillary electrophoresis (CE) and microfluidic chip (MC) devices are relatively mature technologies, but this book demonstrates how they can be integrated into a single, revolutionary device that can provide on-site analysis of samples when laboratory services are unavailable. By introducing the combination of CE and MC technology, Microfluidic Chip-Capillary Electrophoresis Devices broadens the scope of chemical analysis, particularly in the biomedical, food, and environmental sciences.The book gives an overview of the development of MC and CE technology as well as technology that now allows

  18. A lymph nodal capillary-cavernous hemangioma.

    Science.gov (United States)

    Dellachà, A; Fulcheri, E; Campisi, C

    1999-09-01

    A capillary-cavernous hemangioma in an obturator lymph node was found incidentally in a 64 year-old woman who had undergone unilateral salpingo-oophorectomy and lymphadenectomy for an ovarian neoplasm. Vascular tumors of lymph nodes are briefly reviewed including eight previously described nodal capillary-cavernous hemangiomas. The association with other splanchnic hemangiomas is pointed out and the likelihood that the lesion is a hamartoma rather than a true neoplasm is addressed. Despite its rarity, this entity needs to be recognized by lymphologists who image lymph nodes by lymphangiography as well as by lymph nodal pathologists. PMID:10494525

  19. Intracerebral Capillary Hemangioma: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Youn, In Young; Kim, Jae Kyun; Byun, Jun Soo [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of); Park, Eon Sub [Dept. of Radiology, Chung Ang University Medical Center, Chung Ang University College of Medicine, Seoul (Korea, Republic of)

    2012-01-15

    Intracerebral capillary hemangiomas are very rare benign vascular tumors that mostly occur during infancy. We described a 69-year-old man with generalized tonic-clonic seizures who was diagnosed with an intracranial mass. Multidetector computed tomography, magnetic resonance imaging and digital subtraction angiography studies were performed for evaluation of brain, and there was a well-enhancing mass found in the right temporal lobe without a definite feeding vessel. The patient underwent surgery and the pathologic examination demonstrated marked proliferation of small vessels with a lobular pattern in the brain parenchyma, which was confirmed to be capillary hemangioma.

  20. Frozen soil barriers for hazardous waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    Dash, J.G.; Leger, R. [Univ. of Washington, Seattle, WA (United States); Fu, H.Y. [Univ. of California, Santa Barbara, CA (United States)

    1997-12-31

    Laboratory and full field measurements have demonstrated the effectiveness of artificial ground freezing for the containment of subsurface hazardous and radioactive wastes. Bench tests and a field demonstration have shown that cryogenic barriers are impenetrable to aqueous and non aqueous liquids. As a result of the successful tests the US Department of Energy has designated frozen ground barriers as one of its top ten remediation technologies.

  1. Blood Perfusion in Microfluidic Models of Pulmonary Capillary Networks: Role of Geometry and Hematocrit

    Science.gov (United States)

    Stauber, Hagit; Waisman, Dan; Sznitman, Josue; Technion-IIT Team; Department of Neonatology Carmel Medical Center; Faculty of Medicine-Technion IIT Collaboration

    2015-11-01

    Microfluidic platforms are increasingly used to study blood microflows at true physiological scale due to their ability to overcome manufacturing obstacle of complex anatomical morphologies, such as the organ-specific architectures of the microcirculation. In the present work, we utilize microfluidic platforms to devise in vitro models of the underlying pulmonary capillary networks (PCN), where capillary lengths and diameters are similar to the size of RBCs (~ 5-10 μm). To better understand flow characteristics and dispersion of red blood cells (RBCs) in PCNs, we have designed microfluidic models of alveolar capillary beds inspired by the seminal ``sheet flow'' model of Fung and Sobin (1969). Our microfluidic PCNs feature confined arrays of staggered pillars with diameters of ~ 5,7 and 10 μm, mimicking the dense structure of pulmonary capillary meshes. The devices are perfused with suspensions of RBCs at varying hematocrit levels under different flow rates. Whole-field velocity patterns using micro-PIV and single-cell tracking using PTV are obtained with fluorescently-labelled RBCs and discussed. Our experiments deliver a real-scale quantitative description of RBC perfusion characteristics across the pulmonary capillary microcirculation.

  2. Vectorial detection of sub-microscale capillary curvature by laser beam profile

    Science.gov (United States)

    Verma, Gopal; Singh, Kamal P.

    2015-10-01

    We demonstrate a simple and non-invasive optical technique to detect direction and magnitude of long-range, sub-microscale capillary curvature of fluid interfaces in various situations. By analyzing magnitude and direction of the distorted spatial profile of the laser beam, following its weak Fresnel's reflection from the air-water interface, ultra-low curvature of 0.1 μm-1 caused by dipped slides, glass tubes, and microscopic twisted silk fibers was measured up to six capillary lengths away from the object. The flexibility of this technique allows us to measure curvature of remotely placed fluid-fluid interfaces and interaction between capillary curves of multiple objects. The high sensitivity of our technique is demonstrated in measuring magnetic susceptibility of water and the full spatial profile of deformation under weak magnetic field. This technique might find applications in precision measurements in optofluidics and interface physics.

  3. Test results of reliable and very high capillary multi-evaporators / condenser loop

    Energy Technology Data Exchange (ETDEWEB)

    Van Oost, S.; Dubois, M.; Bekaert, G. [Societe Anonyme Belge de Construction Aeronautique - SABCA (Belgium)

    1996-12-31

    The paper present the results of various SABCA activities in the field of two-phase heat transport system. These results have been based on a critical review and analysis of the existing two-phase loop and of the future loop needs in space applications. The research and the development of a high capillary wick (capillary pressure up to 38 000 Pa) are described. These activities have led towards the development of a reliable high performance capillary loop concept (HPCPL), which is discussed in details. Several loop configurations mono/multi-evaporators have been ground tested. The presented results of various tests clearly show the viability of this concept for future applications. Proposed flight demonstrations as well as potential applications conclude this paper. (authors) 7 refs.

  4. Viscosity measurement in the capillary tube viscometer under unsteady flow

    International Nuclear Information System (INIS)

    The objective of the present study is to develop a new device that the viscous characteristics of fluids are determined by applying the unsteady flow concept to the traditional capillary tube viscometer. The capillary tube viscometer consists of a small cylindrical reservoir, capillary tube, a load cell system that measures the mass flow rate, interfaces, and computer. Due to the small size of the reservoir the height of liquid in the reservoir decreases as soon as the liquid in the reservoir drains out through the capillary and the mass flow rate in the capillary decreases as the hydrostatic pressure in the reservoir decreases resulting in a decrease of the shear rate in the capillary tube. The instantaneous shear rate and driving force in the capillary tube are determined by measuring the mass flow rate through the capillary, and the fluid viscosity is determined from the measured flow rate and the driving force

  5. A Rare Association of Trigeminal Autonomic Cephalgia: Pontine Capillary Telangiectasia

    OpenAIRE

    Gocmen, Rahsan; Kurt, Erdal; Arslan, Sabina; Unal-Cevik, Isin; Karli Oguz, Kader; Tezer, F Irsel

    2015-01-01

    This report describes a case of pontine capillary telangiectasia in a 43-year-old woman with a clinical diagnosis of trigeminal autonomic cephalgia. The possible association with pontine capillary telangiectasia and trigeminal autonomic cephalgia is discussed.

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

    Directory of Open Access Journals (Sweden)

    Cheng-Huan Hsieh

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

  7. St. John's Wort constituents modulate P-glycoprotein transport activity at the blood-brain barrier.

    NARCIS (Netherlands)

    Ott, M.; Huls, M.; Cornelius, M.G.; Fricker, G.

    2010-01-01

    PURPOSE: The purpose of this study was to investigate the short-term signaling effects of St. John's Wort (SJW) extract and selected SJW constituents on the blood-brain barrier transporter P-glycoprotein and to describe the role of PKC in the signaling. METHODS: Cultured porcine brain capillary endo

  8. Field tests with vertical perforated drain pipes used for beach protection at Southern Holmsland Barrier on the Danish North Sea Coast

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Fredsøe, Jørgen

    In accordance with the agreement of 18 August 2004 between Skagen Innovation Center (SIC) and the Danish Governmental Coastal Authority (KDI) a field test with the purpose of demonstrating the efficiency of the SIC vertical drain method as a mean for coastal protecting was initiated in a meeting 24...

  9. Field tests with vertical perforated drain pipes used for beach protection at Southern Holmsland Barrier on the Danish North Sea Coast (half year report)

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Fredsøe, Jørgen

    In accordance with the agreement of 18 August 2004 between Skagen Innovation Center (SIC) and the Danish Governmental Coastal Authority (KDI) a field test with the purpose of demonstrating the efficiency of the SIC vertical drain method as a mean for coastal protecting was initiated in a meeting 24...

  10. Application of CHESS single-bounce capillaries at synchrotron beamlines

    Science.gov (United States)

    Huang, R.; Szebenyi, T.; Pfeifer, M.; Woll, A.; Smilgies, D.-M.; Finkelstein, K.; Dale, D.; Wang, Y.; Vila-Comamala, J.; Gillilan, R.; Cook, M.; Bilderback, D. H.

    2014-03-01

    Single-bounce capillaries are achromatic X-ray focusing optics that can provide efficient and high demagnification focusing with large numerical apertures. Capillary fabrication at CHESS can be customized according to specific application requirements. Exemplary applications are reviewed in this paper, as well as recent progress on condensers for high-resolution transmission X-ray microscopy and small focal size capillaries.

  11. Cyclodextrin-Functionalized Monolithic Capillary Columns: Preparation and Chiral Applications.

    Science.gov (United States)

    Adly, Frady G; Antwi, Nana Yaa; Ghanem, Ashraf

    2016-02-01

    In this review, the recently reported approaches for the preparation of cyclodextrin-functionalized capillary monolithic columns are highlighted, with few applications in chiral separations using capillary liquid chromatography (CLC) and capillary electrochromatography (CEC). Chirality 28:97-109, 2016. © 2015 Wiley Periodicals, Inc.

  12. Design criteria for SW-205 capillary system

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, W.J.

    1989-04-01

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

  13. Planetary In Situ Capillary Electrophoresis System (PISCES)

    Science.gov (United States)

    Willis, P. A.; Stockton, A. M.; Mora, M. F.; Cable, M. L.; Bramall, N. E.; Jensen, E. C.; Jiao, H.; Lynch, E.; Mathies, R. A.

    2012-10-01

    We propose to develop PISCES, a 3-kg, 2W, flight-capable microfluidic lab-on-a-chip capillary electrophoresis analyzer capable of ingesting solid, liquid, or gas samples and performing a suite of chemical analyses with parts per trillion sensitivity.

  14. Imbibition of ``Open Capillary'': Fundamentals and Applications

    Science.gov (United States)

    Tani, Marie; Kawano, Ryuji; Kamiya, Koki; Okumura, Ko

    2015-11-01

    Control or transportation of small amount of liquid is one of the most important issues in various contexts including medical sciences or pharmaceutical industries to fuel delivery. We studied imbibition of ``open capillary'' both experimentally and theoretically, and found simple scaling laws for both statics and dynamics of the imbibition, similarly as that of imbibition of capillary tubes. Furthermore, we revealed the existence of ``precursor film,'' which developed ahead of the imbibing front, and the dynamics of it is described well by another scaling law for capillary rise in a corner. Then, to show capabilities of open capillaries, we demonstrated two experiments by fabricating micro mixing devices to achieve (1) simultaneous multi-color change of the Bromothymol blue (BTB) solution and (2) expression of the green florescent protein (GFP). This research was partly supported by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). M. T. is supported by the Japan Society for the Promotion of Science Research Fellowships for Young Scientists.

  15. Shift dynamics of capillary self-alignment

    NARCIS (Netherlands)

    Arutinov, G.; Mastrangeli, M.; Smits, E.C.P.; Heck, G.V.; Schoo, H.F.M.; Toonder, J.J.M. den; Dietzel, A.H.

    2014-01-01

    This paper describes the dynamics of capillary self-alignment of components with initial shift offsets from matching receptor sites. The analysis of the full uniaxial self-alignment dynamics of foil-based mesoscopic dies from pre-alignment to final settling evidenced three distinct, sequential regim

  16. Macroscopic theory for capillary-pressure hysteresis.

    Science.gov (United States)

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

    2015-03-01

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

  17. Engineered Barrier Testing at the INEEL Engineered Barriers Test Facility: FY-1997 and FY-1998

    International Nuclear Information System (INIS)

    Engineered barriers of two designs are being tested at the Engineered Barriers Test Facility (EBTF) at the Idaho National Engineering and Environmental Laboratory. This report describes the test facility, barrier designs, and instruments used to monitor the test plots. Wetting tests conducted on the test plots in FY-97 are described and data collected from monitoring the test plots before, during and after the wetting tests are used to evaluate the performance of the covers during FY-97 and FY-98. Replicates of two engineered barrier designs were constructed in the EBTF cells. The first design comprises a thick, vegetated soil cover. The second design incorporates a capillary/biobarrier within the vegtated soil cover. The capillary barrier uses the textural break between an upper, fine textured soil and a lower, coarser-textured gravel layer to inhibit drainage under unsaturated conditions while increasing soil moisture storage in the root zone. Evaporation and transpiration by plants (although the test plots have not yet been vegetated) are used to recycle water stored in the soil back to the atmosphere. A geotextile fabric is used to maintain separation of the soil and gravel layers. A thick layer of cobbles beneath the gravel layer serves as a biobarrier to prevent intrusion of plant roots and burrowing animals into underlying waste (there is no waste in the test plots). Each test plot was instrumented with time domain reflectometry probes and neutron probe access tubes to measure moisture contents, tensiometers, heat dissipation sensors, and thermocouple psychrometers to measure matric potentials, thermocouples to measure soil temperature, and ion-exchange resin beads to monitor tracer movement. Each drainage sump is equipped with a tipping bucket instrument and pressure transducer to measure drainage. Precipitation is measured using a heated rain gauge located at the EBTF. Instrument calibration equation coefficients are presented, and data reduction

  18. Engineered Barrier Testing at the INEEL Engineered Barriers Test Facility: FY-1997 and FY-1999

    Energy Technology Data Exchange (ETDEWEB)

    Keck, K. N.; Porro, I.

    1998-09-01

    Engineered barriers of two designs are being tested at the Engineered Barriers Test Facility (EBTF) at the Idaho National Engineering and Environmental Laboratory. This report describes the test facility, barrier designs, and instruments used to monitor the test plots. Wetting tests conducted on the test plots in FY-97 are described and data collected from monitoring the test plots before, during and after the wetting tests are used to evaluate the performance of the covers during FY-97 and FY-98. Replicates of two engineered barrier designs were constructed in the EBTF cells. The first design comprises a thick, vegetated soil cover. The second design incorporates a capillary/biobarrier within the vegtated soil cover. The capillary barrier uses the textural break between an upper, fine textured soil and a lower, coarser-textured gravel layer to inhibit drainage under unsaturated conditions while increasing soil moisture storage in the root zone. Evaporation and transpiration by plants (although the test plots have not yet been vegetated) are used to recycle water stored in the soil back to the atmosphere. A geotextile fabric is used to maintain separation of the soil and gravel layers. A thick layer of cobbles beneath the gravel layer serves as a biobarrier to prevent intrusion of plant roots and burrowing animals into underlying waste (there is no waste in the test plots). Each test plot was instrumented with time domain reflectometry probes and neutron probe access tubes to measure moisture contents, tensiometers, heat dissipation sensors, and thermocouple psychrometers to measure matric potentials, thermocouples to measure soil temperature, and ion-exchange resin beads to monitor tracer movement. Each drainage sump is equipped with a tipping bucket instrument and pressure transducer to measure drainage. Precipitation is measured using a heated rain gauge located at the EBTF. Instrument calibration equation coefficients are presented, and data reduction

  19. A capillary optical fiber modulator derivates from magnetic fluid

    Science.gov (United States)

    Yang, Xinghua; Liu, Yanxin; Zheng, Yao; Li, Shouzhu; Yuan, Libo; Yuan, Tingting; Tong, Chengguo

    2013-09-01

    A novel in-fiber integrated modulator based on magnetic fluid is proposed. The Fe3O4 magnetic fluid is encapsulated into a specially designed capillary optical fiber with a circular waveguide. Experimental results show that the light at 632.8 nm in the circular waveguide can be modulated by only 2.17×10-2 μL of the magnetic fluid under magnetic field. A wide range of modulation-depth from 44% to 75% can be obtained by adjusting the external magnetic field strength, temperature and the concentration of the magnetic fluid. In addition, the modulator shows good stability and repeatability. This work has great potentials in the integrated optical devices such as tunable in-fiber modulators, optical switches and magnetic sensors.

  20. Development of engineered barrier

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  1. Development of engineered barrier

    International Nuclear Information System (INIS)

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and 316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  2. An in vitro model of the glomerular capillary wall using electrospun collagen nanofibres in a bioartificial composite basement membrane.

    Directory of Open Access Journals (Sweden)

    Sadie C Slater

    Full Text Available The filtering unit of the kidney, the glomerulus, contains capillaries whose walls function as a biological sieve, the glomerular filtration barrier. This comprises layers of two specialised cells, glomerular endothelial cells (GEnC and podocytes, separated by a basement membrane. Glomerular filtration barrier function, and dysfunction in disease, remains incompletely understood, partly due to difficulties in studying the relevant cell types in vitro. We have addressed this by generation of unique conditionally immortalised human GEnC and podocytes. However, because the glomerular filtration barrier functions as a whole, it is necessary to develop three dimensional co-culture models to maximise the benefit of the availability of these cells. Here we have developed the first two tri-layer models of the glomerular capillary wall. The first is based on tissue culture inserts and provides evidence of cell-cell interaction via soluble mediators. In the second model the synthetic support of the tissue culture insert is replaced with a novel composite bioartificial membrane. This consists of a nanofibre membrane containing collagen I, electrospun directly onto a micro-photoelectroformed fine nickel supporting mesh. GEnC and podocytes grew in monolayers on either side of the insert support or the novel membrane to form a tri-layer model recapitulating the human glomerular capillary in vitro. These models will advance the study of both the physiology of normal glomerular filtration and of its disruption in glomerular disease.

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

    Science.gov (United States)

    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.

  4. Transport of two-dimensional electrons through magnetic barriers

    CERN Document Server

    Kubrak, V

    2001-01-01

    scattering rate is an important probe for the unusual electron dynamics inside the barrier, which is different for different barrier types. It is studied how states bound within the barrier or channelled along zero-field contour lines affect the transport through the barriers. To facilitate the interpretation, the experimental results are compared to semi-ballistic Monte Carlo simulations. In the semi-ballistic regime, the barrier resistance of small-amplitude simple barriers is found to be mainly due to ballistic reflection and to be almost independent of the scattering rate. For opaque barriers, scattering-assisted transmission, which results in a decrease of the resistance with increasing scattering rate, and orbits skipping along the edge of the channel are found to be important. In contrast, the resistance of barriers with a zero-field contour increases with increasing scattering rate, which is ascribed to scattering into the snake orbits that are channelled along the contour. It is also demonstrated how...

  5. Contribution to the development of new analytical methods by the coupling between capillary electrophoresis and mass spectrometry (ICP-MS and ESI-MS): applications to the nuclear and biological fields

    International Nuclear Information System (INIS)

    The coupling between chromatographic and electrophoretic separation techniques and mass spectrometry is used to combine the efficiency of the separation technique to the selectivity and sensitivity of the detectors. In this work, the number of applications of the CE-MS couplings has been increased. New analytical methods have been set up in the nuclear and biological fields. New analytical methods for the determination of fission products (cesium and lanthanides) have been developed by CE-ICP-MS. They enable to determine both concentration and isotopic composition of the fission products for very low detection limits (ng/mL by CE-Q-ICPMS, pg/mL by CE-HR-ICP-MS), since all the isobaric interferences are resolved. Moreover, only some nano-liters of sample are necessary to perform the analysis. These method have been applied with success to a simulated sample of spent fuel, to a nuclear sample from PUREX process and to a leaching of MOX fuel. Then, lanthanides have been analysed by CE-ESI-MS and the capability of ESI-MS to provide structural information has been studied. Elementary information has been obtained for strong potentials. Structural information has been obtained for low potentials. Finally, a new analytical method by CE-ESI-MS for the determination of 10B-boronophenylalanine (10B-BPA) has been developed for Boron Neutron Capture Therapy (BNCT). It has been applied to the cellular lines F98 and HUVEC. This CE-ESI-MS method has been validated by HR-ICP-MS. It enables a direct quantification of the chemical form 10B-BPA in samples of limited size (some nano-liters) and for low concentrations (ng/mL). As a consequence, this CE-ESI-MS method has enabled the study of the kinetics of 10B-BPA release and uptake for the F98 cells. (author)

  6. A complete soil hydraulic model accounting for capillary and adsorptive water retention, capillary and film conductivity, and hysteresis

    NARCIS (Netherlands)

    Sakai, Masaru; Van Genuchten, Martinus Th; Alazba, A. A.; Setiawan, Budi Indra; Minasny, Budiman

    2015-01-01

    A soil hydraulic model that considers capillary hysteretic and adsorptive water retention as well as capillary and film conductivity covering the complete soil moisture range is presented. The model was obtained by incorporating the capillary hysteresis model of Parker and Lenhard into the hydraulic

  7. Online comprehensive two-dimensional ion chromatography × capillary electrophoresis.

    Science.gov (United States)

    Ranjbar, Leila; Gaudry, Adam J; Breadmore, Michael C; Shellie, Robert A

    2015-09-01

    A comprehensively coupled online two-dimensional ion chromatography-capillary electrophoresis (IC × CE) system for quantitative analysis of inorganic anions and organic acids in water is introduced. The system employs an in-house built sequential injection-capillary electrophoresis instrument and a nonfocusing modulation interface comprising a tee-piece and a six-port two-position injection valve that allows comprehensive sampling of the IC effluent. High field strength (+2 kV/cm) enables rapid second-dimension separations in which each peak eluted from the first-dimension separation column is analyzed at least three times in the second dimension. The IC × CE approach has been successfully used to resolve a suite of haloacetic acids, dalapon, and common inorganic anions. Two-dimensional peak capacity for IC × CE was 498 with a peak production rate of 9 peaks/min. Linear calibration curves were obtained for all analytes from 5 to 225 ng/mL (except dibromoacetic acid (10-225 ng/mL) and tribromoacetic acid (25-225 ng/mL)). The developed approach was used to analyze a spiked tap water sample, with good measured recoveries (69-119%).

  8. Safety-barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2007-01-01

    are discussed. A simple method for quantification of safety-barrier diagrams is proposed, including situations where safety barriers depend on shared common elements. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk......Safety-barrier diagrams and the related so-called "bow-tie" diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation with other methods such as fault trees and Bayesian networks...... analysis with operational safety management....

  9. Extremal surface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Engelhardt, Netta; Wall, Aron C. [Department of Physics, University of California,Santa Barbara, CA 93106 (United States)

    2014-03-13

    We present a generic condition for Lorentzian manifolds to have a barrier that limits the reach of boundary-anchored extremal surfaces of arbitrary dimension. We show that any surface with nonpositive extrinsic curvature is a barrier, in the sense that extremal surfaces cannot be continuously deformed past it. Furthermore, the outermost barrier surface has nonnegative extrinsic curvature. Under certain conditions, we show that the existence of trapped surfaces implies a barrier, and conversely. In the context of AdS/CFT, these barriers imply that it is impossible to reconstruct the entire bulk using extremal surfaces. We comment on the implications for the firewall controversy.

  10. Safety- barrier diagrams

    DEFF Research Database (Denmark)

    Duijm, Nijs Jan

    2008-01-01

    Safety-barrier diagrams and the related so-called 'bow-tie' diagrams have become popular methods in risk analysis. This paper describes the syntax and principles for constructing consistent and valid safety-barrier diagrams. The relation of safety-barrier diagrams to other methods such as fault...... trees and Bayesian networks is discussed. A simple method for quantification of safety-barrier diagrams is proposed. It is concluded that safety-barrier diagrams provide a useful framework for an electronic data structure that integrates information from risk analysis with operational safety management....

  11. Method of making tapered capillary tips with constant inner diameters

    Science.gov (United States)

    Kelly, Ryan T.; Page, Jason S.; Tang, Keqi; Smith, Richard D.

    2009-02-17

    Methods of forming electrospray ionization emitter tips are disclosed herein. In one embodiment, an end portion of a capillary tube can be immersed into an etchant, wherein the etchant forms a concave meniscus on the outer surface of the capillary. Variable etching rates in the meniscus can cause an external taper to form. While etching the outer surface of the capillary wall, a fluid can be flowed through the interior of the capillary tube. Etching continues until the immersed portion of the capillary tube is completely etched away.

  12. Spatiotemporal measurement of surfactant distribution on gravity-capillary waves

    CERN Document Server

    Strickland, Stephen L; Daniels, Karen E

    2015-01-01

    Materials adsorbed to the surface of a fluid -- for instance, crude oil, biogenic slicks, or industrial/medical surfactants -- will move in response to surface waves. Due to the difficulty of non-invasive measurement of the spatial distribution of a molecular monolayer, little is known about the dynamics that couple the surface waves and the evolving density field. Here, we report measurements of the spatiotemporal dynamics of the density field of an insoluble surfactant driven by gravity-capillary waves in a shallow cylindrical container. Standing Faraday waves and traveling waves generated by the meniscus are superimposed to create a non-trivial surfactant density field. We measure both the height field of the surface using moir\\'e-imaging, and the density field of the surfactant via the fluorescence of NBD-tagged phosphatidylcholine, a lipid. Through phase-averaging stroboscopically-acquired images of the density field, we determine that the surfactant accumulates on the leading edge of the traveling menis...

  13. Capillary Interactions between a Probe Tip and a Nanoparticle

    Institute of Scientific and Technical Information of China (English)

    SUN Li-Ning; WANG Le-Feng; RONG Wei-Bin

    2008-01-01

    To understand capillary interactions between probe tips and nanoparticles under ambient conditions,a theoretical model of capillary forces between them is developed based on the geometric relations. It is found that the contribution of surface tension force to the total capillary force attains to similar order of magnitude as the capillary pressure force in many cases.It is also shown that the tip shape and the radial distance of the meniscus have great influence on the capillary force.The capillary force decreases with the increasing separation distances,and the variance of the contact angles may change the magnitudes of capillary forces several times at large radial distances.The applicability of the symmetric meniscus approximation is discussed.

  14. Design of dry barriers for containment of contaminants in unsaturated soils

    Energy Technology Data Exchange (ETDEWEB)

    Morris, C.E. [Univ. of Wollongong (Australia); Thomson, B.M.; Stormont, J.C. [Univ. of New Mexico, Albuquerque, NM (United States)

    1997-12-31

    A dry barrier is a region of very dry conditions in unsaturated soil that prevents vertical migration of water created by circulating dry air through the formation. Dry soil creates a barrier to vertical water movement by decreasing the soil`s hydraulic conductivity, a concept also used in capillary barriers. A dry barrier may be a viable method for providing containment of a contaminant plume in a setting with a thick unsaturated zone and dry climate. The principal factors which determine the feasibility of a dry barrier include: (1) an and environment, (2) thick vadose zone, and (3) the ability to circulate air through the vadose zone. This study investigated the technical and economic considerations associated with creating a dry barrier to provide containment of a hypothetical 1 ha aqueous contaminant plume. The concept appears to be competitive with other interim containment methods such as ground freezing.

  15. Design of dry barriers for containment of contaminants in unsaturated soils

    International Nuclear Information System (INIS)

    A dry barrier is a region of very dry conditions in unsaturated soil that prevents vertical migration of water created by circulating dry air through the formation. Dry soil creates a barrier to vertical water movement by decreasing the soil's hydraulic conductivity, a concept also used in capillary barriers. A dry barrier may be a viable method for providing containment of a contaminant plume in a setting with a thick unsaturated zone and dry climate. The principal factors which determine the feasibility of a dry barrier include: (1) an and environment, (2) thick vadose zone, and (3) the ability to circulate air through the vadose zone. This study investigated the technical and economic considerations associated with creating a dry barrier to provide containment of a hypothetical 1 ha aqueous contaminant plume. The concept appears to be competitive with other interim containment methods such as ground freezing

  16. Electromagnetohydrodynamic flow of blood and heat transfer in a capillary with thermal radiation

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, A. [Department of Mathematics, Jadavpur University, Kolkata 700032 (India); Shit, G.C., E-mail: gopal_iitkgp@yahoo.co.in [Department of Mathematics, Jadavpur University, Kolkata 700032 (India); Institute of Mathematical Sciences, Chennai 600113 (India)

    2015-03-15

    This paper presents a comprehensive theoretical study on heat transfer characteristics together with fully developed electromagnetohydrodynamic flow of blood through a capillary, having electrokinetic effects by considering the constant heat flux at the wall. The effect of thermal radiation and velocity slip condition have been taken into account. A rigorous mathematical model for describing Joule heating in electro-osmotic flow of blood including the Poisson–Boltzmann equation, the momentum equation and the energy equation is developed. The alterations in the thermal transport phenomenon, induced by the variation of imposed electromagnetic effects, are thoroughly explained through an elegant mathematical formalism. Results presented here pertain to the case where the height of the capillary is much greater than the thickness of electrical double layer comprising the stern and diffuse layers. The essential features of the electromagnetohydrodynamic flow of blood and associated heat transfer characteristics through capillary are clearly highlighted by the variations in the non-dimensional parameters for velocity profile, temperature profile and the Nusselt number. The study reveals that the temperature of blood can be controlled by regulating Joule heating parameter. - Highlights: • Electromagnetohydrodynamic flow of blood in capillary is studied. • Potential electric field is applied for driving elecroosmotic flow of blood. • Effect of thermal radiation, Joule heating and velocity slip is investigated. • Thermal radiation bears the significant change in the temperature field.

  17. Electromagnetohydrodynamic flow of blood and heat transfer in a capillary with thermal radiation

    International Nuclear Information System (INIS)

    This paper presents a comprehensive theoretical study on heat transfer characteristics together with fully developed electromagnetohydrodynamic flow of blood through a capillary, having electrokinetic effects by considering the constant heat flux at the wall. The effect of thermal radiation and velocity slip condition have been taken into account. A rigorous mathematical model for describing Joule heating in electro-osmotic flow of blood including the Poisson–Boltzmann equation, the momentum equation and the energy equation is developed. The alterations in the thermal transport phenomenon, induced by the variation of imposed electromagnetic effects, are thoroughly explained through an elegant mathematical formalism. Results presented here pertain to the case where the height of the capillary is much greater than the thickness of electrical double layer comprising the stern and diffuse layers. The essential features of the electromagnetohydrodynamic flow of blood and associated heat transfer characteristics through capillary are clearly highlighted by the variations in the non-dimensional parameters for velocity profile, temperature profile and the Nusselt number. The study reveals that the temperature of blood can be controlled by regulating Joule heating parameter. - Highlights: • Electromagnetohydrodynamic flow of blood in capillary is studied. • Potential electric field is applied for driving elecroosmotic flow of blood. • Effect of thermal radiation, Joule heating and velocity slip is investigated. • Thermal radiation bears the significant change in the temperature field

  18. Insulin binding to brain capillaries is reduced in genetically obese, hyperinsulinemic Zucker rats

    International Nuclear Information System (INIS)

    In order to study the role of plasma insulin in regulating the binding of insulin to the endothelium of the blood-brain barrier (BBB), insulin binding to a purified preparation of brain capillaries was measured in both genetically obese Zucker rats and lean Zucker controls. We found a reduction of 65% in brain capillary insulin binding site number in the obese compared to lean rats with no change in receptor affinity. Furthermore, specific insulin binding to brain capillaries was negatively correlated (p less than 0.05) to the plasma insulin level, suggesting a role for plasma insulin in regulating insulin binding. A similar relationship was observed between insulin receptor number in liver membranes and the plasma insulin level. We conclude that obese, hyperinsulinemic Zucker rats exhibit a reduction in the number of BBB insulin receptors, which parallels the reduction seen in other peripheral tissues. Since insulin receptors have been hypothesized to participate in the transport of insulin across the BBB, the reduction observed in the obese rats may account for the decrease in cerebrospinal fluid insulin uptake previously demonstrated in these animals

  19. A capillary pumping device utilizing super-hydrophobic silicon grass

    International Nuclear Information System (INIS)

    In this study, we show that a compact silicon grass surface can be generated by utilizing the induced coupled plasma method with suitably chosen fabrication parameters. This super-hydrophobic structure suspends deionized water on top of the grass and keeps the contact angle at around 153°. The silicon grass is used to improve the driving efficiency of a capillary pumping micro-duct (without sidewalls), which is completely defined by a bottom hydrophilic stripe (adjacent to a Teflon substrate) and a fully top-covered hydrophobic Teflon surface which is coated on a glass substrate. The channel has a height of 3 µm and a width of 100 µm. In this work, the Teflon substrate is replaced with the silicon grass surface. When the fluid is flowing through the micro-duct on the stripe, the interface between the silicon grass and the hydrophilic stripe forms a stable air cushion barrier to the fluid, thus effectively reducing the frictional force. By changing only the interface with this replacement, we demonstrate that the average measured velocities of the new design show improvements of 21% and 17% in the driving efficiency over the original design for transporting deionized water and human blood, respectively. It is also shown that the measured data of the present design are closer to the values predicted by a theoretical analysis which relates the flow velocity to the contact angles, surface tension and fluid viscosity

  20. Observations of soft x-ray emission and wall ablation in a fast low-energy pulsed capillary discharge

    Science.gov (United States)

    Valdivia, M. P.; Wyndham, E. S.; Ramos-Moore, E.; Ferrari, P.; Favre, M.

    2013-08-01

    We report on experimental observations of pulsed capillary discharges aimed at soft x-ray production within the water-window range. Through systematical studies of capillary tube characteristics and discharge conditions, radiation emission was analysed. Plasma properties were studied by means of spectrometry, wide-band PIN diode signals and plasma micro-channel plate imaging. Surface and bulk material analyses were performed using scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and Auger electron spectroscopy (AES) in order to characterize the capillary inner surface after discharges. We report on hollow cathode effect enhancement by modification of cathode electrode aperture, as well as pressure conditions along the capillary, which were found to have an important effect over plasma and x-ray yields due to the modification of local electrical field and gas density. Capillary tube material and inner diameter also modified the interaction of the plasma channel with the capillary surface, thus modifying the plasma source characteristics. It was found that emission of the NVI line at 28.8 Å can be enhanced within the conditions studied, from no significant emission to sources delivering an average brightness of over 70.0 mW mm-2 per 2π sr. This demonstrates that hollow cathode electrons and plasma-wall interaction and ablation have a direct impact on emission quality.

  1. The geometry and wetting of capillary folding

    CERN Document Server

    Péraud, Jean-Philippe

    2014-01-01

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

  2. Capillary flow through heat-pipe wicks

    Science.gov (United States)

    Eninger, J. E.

    1975-01-01

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

  3. Transversally periodic solitary gravity-capillary waves.

    Science.gov (United States)

    Milewski, Paul A; Wang, Zhan

    2014-01-01

    When both gravity and surface tension effects are present, surface solitary water waves are known to exist in both two- and three-dimensional infinitely deep fluids. We describe here solutions bridging these two cases: travelling waves which are localized in the propagation direction and periodic in the transverse direction. These transversally periodic gravity-capillary solitary waves are found to be of either elevation or depression type, tend to plane waves below a critical transverse period and tend to solitary lumps as the transverse period tends to infinity. The waves are found numerically in a Hamiltonian system for water waves simplified by a cubic truncation of the Dirichlet-to-Neumann operator. This approximation has been proved to be very accurate for both two- and three-dimensional computations of fully localized gravity-capillary solitary waves. The stability properties of these waves are then investigated via the time evolution of perturbed wave profiles. PMID:24399922

  4. Capillary solitons on a levitated medium.

    Science.gov (United States)

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

    2015-07-01

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

  5. Capillary Hemangioma of the Fallopian Tube.

    Science.gov (United States)

    Katiyar, Richa; Patne, Shashikant C U; Bharti, Shreekant; Jain, Madhu

    2016-04-01

    Neoplastic lesions of the fallopian tube are rarely seen by surgical pathologists. Haemangioma of the fallopian tube is an extremely rare benign neoplasm. A 30-year-old lady with polymenorrhea and dysmenorrhea underwent hysterectomy and bilateral salpingo-oophorectomy. Her left fallopian tube showed a 2mm sized solid nodule in the wall. Histopathological examination revealed a well-defined vascular lesion in the left fallopian tube, consistent with capillary haemangioma. The vascular endothelium was highlighted by CD34 immunostaining. Our literature review has identified 10 cases of cavernous haemangioma of the fallopian tube. To the best of our knowledge, we report the first ever case of capillary haemangioma of the fallopian tube. This is also the smallest detected haemangioma in the fallopian tube. PMID:27190899

  6. Modeling Microscopic Chemical Sensors in Capillaries

    CERN Document Server

    Hogg, Tad

    2008-01-01

    Nanotechnology-based microscopic robots could provide accurate in vivo measurement of chemicals in the bloodstream for detailed biological research and as an aid to medical treatment. Quantitative performance estimates of such devices require models of how chemicals in the blood diffuse to the devices. This paper models microscopic robots and red blood cells (erythrocytes) in capillaries using realistic distorted cell shapes. The models evaluate two sensing scenarios: robots moving with the cells past a chemical source on the vessel wall, and robots attached to the wall for longer-term chemical monitoring. Using axial symmetric geometry with realistic flow speeds and diffusion coefficients, we compare detection performance with a simpler model that does not include the cells. The average chemical absorption is quantitatively similar in both models, indicating the simpler model is an adequate design guide to sensor performance in capillaries. However, determining the variation in forces and absorption as cells...

  7. Metal Ions Analysis with Capillary Zone Electrophoresis.

    Science.gov (United States)

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

    2016-01-01

    Capillary electrophoresis has recently attracted considerable attention as a promising analytical technique for metal ion separations. Significant advances that open new application areas for capillary electrophoresis in the analysis of metal species occurred based on various auxiliary separation principles. These are mainly due to complexation, ion pairing, solvation, and micellization interactions between metal analytes and electrolyte additives, which alter the separation selectivity in a broad range. Likewise, many separation studies for metal ions have been concentrated on the use of preelectrophoresis derivatization methodology. Approaches suitable for manipulation of selectivity for different metal species including metal cations, metal complexes, metal oxoanions, and organometallic compounds, are discussed, with special attention paid to the related electrophoretic system variables using illustrative examples. PMID:27645740

  8. Capillary droplets on Leidenfrost micro-ratchets

    CERN Document Server

    Marin, Alvaro G; Römer, Gertwillem R B E; Pathiraj, B; Veld, Albertus Huis in 't; Lohse, Detlef

    2012-01-01

    Leidenfrost ratchets are structures with the ability of transporting liquid droplets when heated over the critical Leidenfrost temperature. Once this temperature is reached, the droplet levitates over the surface and moves in the direction marked by the slope of the ratchet at terminal velocities around 10 cm/s. Here we provide new experiments with micron-sized ratchets, which have been produced with picosecond pulse laser ablation. In the following work, we use a simple method to measure the thrust driving droplets of capillary size over the micro-ratchets. The mechanism responsible for the force acting on the drop on superheated ratchets has been recently under debate. We extend the recently proposed 'viscous mechanism' proposed by Dupeaux et al. [Europhys. Lett., 96, 58001 (2011)] to capillary droplets and find good agreement with our measurements.

  9. Chemical Power for Microscopic Robots in Capillaries

    CERN Document Server

    Hogg, Tad

    2009-01-01

    The power available to microscopic robots (nanorobots) that oxidize bloodstream glucose while aggregated in circumferential rings on capillary walls is evaluated with a numerical model using axial symmetry and time-averaged release of oxygen from passing red blood cells. Robots about one micron in size can produce up to several tens of picowatts, in steady-state, if they fully use oxygen reaching their surface from the blood plasma. Robots with pumps and tanks for onboard oxygen storage could collect oxygen to support burst power demands two to three orders of magnitude larger. We evaluate effects of oxygen depletion and local heating on surrounding tissue. These results give the power constraints when robots rely entirely on ambient available oxygen and identify aspects of the robot design significantly affecting available power. More generally, our numerical model provides an approach to evaluating robot design choices for nanomedicine treatments in and near capillaries.

  10. PILOT-SCALE EVALUATION OF ENGINEERED BARRIER SYSTEMS FOR THE YUCCA MOUNTAIN PROJECT

    International Nuclear Information System (INIS)

    This paper describes two quarter-scale experiments (1.4 m diameter) and associated numerical analyses on granular backfill engineered barrier systems in support of the Yucca Mountain Project for the potential repository. The two configurations include a sloped capillary barrier and a plain backfill. The tests involve application of dyed water as a constant line infiltration source along the top of the test set-up, monitoring water movement through the test, and measuring water exiting the experiments. A complete water balance estimate is made for each test, and observed water movement is compared with (1) detailed numerical analyses conducted using the TOUGH2 code for unsaturated flow in porous media and (2) posttest observations. The results of the testing and analyses show that for the injection rates and configuration applied, the capillary barrier design diverts a significant amount of all injected water and the TOUGH2 pretest predictions show qualitative and quantitative agreement with the experimental data

  11. Electrical resistance of muscle capillary endothelium.

    OpenAIRE

    Olesen, S P; Crone, C

    1983-01-01

    A recently developed technique for in vivo determination of the electrical resistance of vascular endothelium in microvessels was applied to the vessels in a thin frog muscle, m. cutaneus pectoris. The technique consists of injection of current via a glass micropipette into a capillary and measurement of the resulting intra- and extravascular potential profiles with another micropipette placed at various distances from the current source. The theory of Peskoff and Eisenberg (1974) was used to...

  12. Separation of Peptides by Pressurized Capillary Electrochromatography

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel gradient pressurized capillary electrochromatography (pCEC) instrument wasdeveloped to separate peptides. Two gradient elution modes, hydrophobic and hydrophilicinteraction mode in pCEC, were performed on this instrument. Baseline separation of sixpeptides was obtained on two gradient modes with C18 column and strong cationic exchangecolumn respectively. The effects of mixer volume and total flow rate of pumps on resolutionwere also discussed.

  13. Capillary Electrophoresis in the Presence of Fosfomycin

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Fosfomyein, a sodim salt of cis-(3-methyloxiranyl) phosphonic acid, was used as electrolyte in binary methanol-water media for capillary electrophoresis. The variety of electroosmotic flow with pH*,methanol concentration and ionic strength was investigated. The migration behavior of nine bases was examined under various conditions, and the separation of thymine, cytosine, 5-flurouracil, 4,6-diamino-pyrimidine, purine was accomplished.

  14. Subsidence and capillary effects in chalks

    OpenAIRE

    Delage, Pierre; Schroeder, Christian; Cui, Yu-Jun

    1996-01-01

    Based on the concepts of the mechanics of unsaturated soils where capillary phenomena arise between the wetting fluid (water) and the non-wetting one (air), the subsidence of chalks containing oil (non-wetting fluid) during water injection (wetting fluid) is analysed. It is shown that the collapse phenomenon of unsaturated soils under wetting provides a physical explanation and a satisfactory prediction of the order of magnitude of the subsidence of the chalk. The use of a well established co...

  15. Familial Pulmonary Capillary Hemangiomatosis Early in Life

    OpenAIRE

    Speer, Christian P.; Mark, Eugene J.; Johannes Wirbelauer; Alexander Marx; Helge Hebestreit

    2011-01-01

    Background. Pulmonary capillary hemangiomatosis (PCH) is a rare disease, especially in infancy. Four infants have been reported up to the age of 12 months. So far, no familial patients are observed at this age. Patients. We report three siblings, two female newborns and a foetus of 15-week gestation of unrelated, healthy parents suffering from histologically proven PCH. The first girl presented with increased O2 requirements shortly after birth and patent ductus arteriosus (PDA). She subseque...

  16. Capillary-scale polarimetry for flowing streams.

    Science.gov (United States)

    Swinney, K; Nodorft, J; Bornhop, D J

    2001-05-01

    A micro-polarimeter with a 40 nL probe volume was configured so that it is compatible with capillary-scale flowing stream analysis. The optical configuration consists of two polarizing optics, a capillary, a laser source and a photodetector which is very simple to configure with low cost components. This unique polarimeter is based upon the interaction of a linearly polarized laser beam and a capillary tube, in this case one with an inner diameter of 250 microns. Side illumination of the tube results in a 360 degrees fan of scattered light, which contains a set of interference fringes that change in response to optically active solutes. Solutes that exhibit optical activity are quantifiable and are detected by analyzing the polarization state of the backscattered light. The ability of the instrument to make extremely sensitive optical activity measurements in flowing streams is shown by the determination of (R)-mandelic acid, with a detection limit of 66 x 10(-6) M (507 x 10(-12) g), and the non-optically active control, glycerol. Additionally, the detector was configured to minimize refractive index perturbations. PMID:11394312

  17. Spatial reconstruction of facial skin capillaries

    Directory of Open Access Journals (Sweden)

    Makarchuk O.I.

    2010-01-01

    Full Text Available To define structural and functional changes of skin capillaries in women of different age groups in this work intraoperational biopsy material of skin of 205 women at the age from 19 to 75 years, that was taken during standard surgery instrumentations for different defects of face and neck skin correction, was investigated. Skin material of cheek face region, temple region of head and anterior neck region was morphologically processed. To define parameters of dermal capillars and spatial reconstruction of intrapapillary capillary loops, serial sections was investigated with the help of morphometry. It was determined, that microcirculation age changes include structural disorders of intrapapillary capillary loops. Essential struc-tural and functional changes observed in skin of cheek region in women of 33-40 years and in temple region of head and anterior neck region in women of 41-50 years. It is typical at the patients with nicotinic dependence, ischemic heart disease, hypertonic disease, a diabetes, and also adiposity of a different degree essential infringement of microvessels bed structure of a skin that gives the basis for allocation of the given contingent of patients as group high intraoperative and postoperative risk at carrying out of operative interventions for correction of face skin involutive changes.

  18. Drinking in Space: The Capillary Beverage Experiment

    Science.gov (United States)

    Wollman, Andrew; Weislogel, Mark; Jenson, Ryan; Graf, John; Pettit, Donald; Kelly, Scott; Lindgren, Kjell; Yui, Kimiya

    2015-11-01

    A selection from as many as 50 different drinks including coffees, teas, and fruit smoothies are consumed daily by astronauts aboard the International Space Station. For practical reasons, the drinks are generally sipped through straws inserted in sealed bags. We present the performance of a special cup designed to allow the drinking operation in much the same manner as on earth, only with the role of gravity replaced by the combined effects of surface tension, wetting, and special container geometry. One can finally `smell the coffee.' Six so-called Space Cups are currently in orbit as part of the Capillary Beverage Experiment which aims to demonstrate specific passive control of poorly wetting aqueous capillary systems through a fun mealtime activity. The mathematical fluid mechanical design process with full numerical simulations is presented alongside experimental results acquired using a drop tower and low-g aircraft before complete characterization aboard the Space Station. Astronaut commentary is both humorous and informative, but the insightful experimental results of the potable space experiment testify to the prospects of new no-moving-parts capillary solutions for certain water-based life support operations aboard spacecraft.

  19. Highly conductive, printable pastes from capillary suspensions

    Science.gov (United States)

    Schneider, Monica; Koos, Erin; Willenbacher, Norbert

    2016-08-01

    We have used the capillary suspension phenomenon to design conductive pastes for printed electronic applications, such as front side metallization of solar cells, without non-volatile, organic additives that often deteriorate electrical properties. Adding a small amount of a second, immiscible fluid to a suspension creates a network of liquid bridges between the particles. This capillary force-controlled microstructure allows for tuning the flow behavior in a wide range. Yield stress and low-shear viscosity can be adjusted such that long-term stability is provided by inhibiting sedimentation, and, even more importantly, narrow line widths and high aspect ratios are accessible. These ternary mixtures, called capillary suspensions, exhibit a strong degree of shear thinning that allows for conventional coating or printing equipment to be used. Finally, the secondary fluid, beneficial for stability and processing of the wet paste, completely evaporates during drying and sintering. Thus, we obtained high purity silver and nickel layers with a conductivity two times greater than could be obtained with state-of-the-art, commercial materials. This revolutionary concept can be easily applied to other systems using inorganic or even organic conductive particles and represents a fundamental paradigm change to the formulation of pastes for printed electronics.

  20. Systems study on engineered barriers: barrier performance analysis

    International Nuclear Information System (INIS)

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed

  1. Systems study on engineered barriers: barrier performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.

    1980-09-01

    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed.

  2. Development of dielectric-barrier-discharge ionization.

    Science.gov (United States)

    Guo, Cheng'an; Tang, Fei; Chen, Jin; Wang, Xiaohao; Zhang, Sichun; Zhang, Xinrong

    2015-03-01

    Dielectric-barrier-discharge ionization is an ambient-ionization technique. Since its first description in 2007, it has attracted much attention in such fields as biological analysis, food safety, mass-spectrometry imaging, forensic identification, and reaction monitoring for its advantages, e.g., low energy consumption, solvent-free method, and easy miniaturization. In this review a brief introduction to dielectric barrier discharge is provided, and then a detailed introduction to the dielectric-barrier-discharge-ionization technique is given, including instrumentation, applications, and mechanistic studies. Based on the summary of reported work, possible future uses of this type of ionization source are discussed at the end. PMID:25510973

  3. Cultural Barriers to International Business Negotiations

    Institute of Scientific and Technical Information of China (English)

    刘竹林; 王俊

    2013-01-01

    Studies in international business negotiation acquire unprecedented significance, as globalization closely connects vari⁃ous business fields into a dynamic whole. Cultural factors play a vital role in international business negotiation. This paper begins with a brief introduction to business negotiation, international business negotiation and significance of cultural barriers to interna⁃tional business negotiation. It then explores two fundamental cultural differences of China and western countries:value differenc⁃es and thinking-pattern differences, which pose cultural barriers. The author then puts forward three strategies to help remove the cultural barriers and achieve successful negotiations.

  4. Multilayer moisture barrier

    Energy Technology Data Exchange (ETDEWEB)

    Pankow, Joel W; Jorgensen, Gary J; Terwilliger, Kent M; Glick, Stephen H; Isomaki, Nora; Harkonen, Kari; Turkulainen, Tommy

    2015-04-21

    A moisture barrier, device or product having a moisture barrier or a method of fabricating a moisture barrier having at least a polymer layer, and interfacial layer, and a barrier layer. The polymer layer may be fabricated from any suitable polymer including, but not limited to, fluoropolymers such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), or ethylene-tetrafluoroethylene (ETFE). The interfacial layer may be formed by atomic layer deposition (ALD). In embodiments featuring an ALD interfacial layer, the deposited interfacial substance may be, but is not limited to, Al.sub.2O.sub.3, AlSiO.sub.x, TiO.sub.2, and an Al.sub.2O.sub.3/TiO.sub.2 laminate. The barrier layer associated with the interfacial layer may be deposited by plasma enhanced chemical vapor deposition (PECVD). The barrier layer may be a SiO.sub.xN.sub.y film.

  5. Cyclodextrins in capillary electrophoresis: recent developments and new trends.

    Science.gov (United States)

    Escuder-Gilabert, L; Martín-Biosca, Y; Medina-Hernández, M J; Sagrado, S

    2014-08-29

    Despite the fact that extensive research in the field of separations by capillary electrophoresis (CE) has been carried out and many reviews have been published in the last years, a specific review on the use and future potential of cyclodextrins (CDs) in CE is not available. This review focuses the attention in the CD-CE topic over the January 2013-February 2014 period (not covered by previous more general CE-reviews). Recent contributions (reviews and research articles) including practical uses (e.g. solute-CD binding constant estimation and further potentials; 19% of publications), developments and applications (mainly chiral and achiral analysis; 38 and 24% of publications, respectively) are summarized in nine comprehensive tables and are commented. Statistics and predictions related to the CD-CE publications are highlighted in order to infer the current and expected research interests. Finally, trends and initiatives on CD-CE attending to real needs or practical criteria are outlined.

  6. Recent developments in electrochemical detection for microchip capillary electrophoresis.

    Science.gov (United States)

    Vandaveer, Walter R; Pasas-Farmer, Stephanie A; Fischer, David J; Frankenfeld, Celeste N; Lunte, Susan M

    2004-11-01

    Significant progress in the development of miniaturized microfluidic systems has occurred since their inception over a decade ago. This is primarily due to the numerous advantages of microchip analysis, including the ability to analyze minute samples, speed of analysis, reduced cost and waste, and portability. This review focuses on recent developments in integrating electrochemical (EC) detection with microchip capillary electrophoresis (CE). These detection modes include amperometry, conductimetry, and potentiometry. EC detection is ideal for use with microchip CE systems because it can be easily miniaturized with no diminution in analytical performance. Advances in microchip format, electrode material and design, decoupling of the detector from the separation field, and integration of sample preparation, separation, and detection on-chip are discussed. Microchip CEEC applications for enzyme/immunoassays, clinical and environmental assays, as well as the detection of neurotransmitters are also described.

  7. A covalent modified hydrophilic capillary for enhanced capillary electrophoresis of biopolymers

    Institute of Scientific and Technical Information of China (English)

    Lian Guo Shan; Xue Yu; Yin Mao Wei; Xiao Hui Zheng; Jian Bin Zheng

    2009-01-01

    δ-Gluconolactone was covalently coupled to aminopropyl derivatized capillary,which created hydrophilic brushes on the inner wall of the capillary.The coated capillary was shown to generate a stable electroosmotic flow(EOF)in the investigated pH range of 2.0-9.0 and to suppress effectively the adsorption of proteins.And it enabled separation of some biopolymer mixtures including basic proteins,DNA and tryptic digested bovine serum albumin(BSA)within 15 min with efficiencies up to 450,000 plates/m.The intra-and inter-day reproducibility of the coating referring to the retention times of proteins were satisfactory with mean relative standard deviations(R.S.D.)of 0.8 and 1.7%,respectively.

  8. In-capillary derivatization and capillary electrophoresis separation of amino acid neurotransmitters from brain microdialysis samples.

    Science.gov (United States)

    Denoroy, Luc; Parrot, Sandrine; Renaud, Louis; Renaud, Bernard; Zimmer, Luc

    2008-09-26

    A new in-capillary derivatization method with naphtalene-2,3-dicarboxyaldehyde (NDA)/CN(-) has been developed for capillary electrophoresis with laser-induced fluorescence detection of brain microdialysate amino acids. Samples are sandwiched between two plugs of reagent mixture at the capillary inlet and subsequently separated. Highest derivatization yields are obtained by using a reagent to sample plug length ratio equal to 4, performing a first electrophoretic mixing followed by a zero potential amplification step before applying the separation voltage and using a NaCN to NDA concentration ratio equal to 1. This new single-step methodology allows the analysis of amino acid neurotransmitters in rat brain microdialysis samples.

  9. Hanford Permanent Isolation Barrier Program: Asphalt technology development

    International Nuclear Information System (INIS)

    An important component of the Hanford Permanent Isolation Barrier is the use of a two-layer composite asphalt system, which provides backup water diversion capabilities if the primary capillary barrier fails to meet infiltration goals. Because of asphalt's potential to perform to specification over the 1000-year design life criterion, a composite asphalt barrier (HMAC/fluid-applied polymer-modified asphalt) is being considered as an alternative to the bentonite clay/high density poly(ethylene) barriers for the low-permeability component of the Hanford Permanent Isolation Barrier. The feasibility of using asphalt as a long-term barrier is currently being studied. Information that must be known is the ability of asphalt to retain desirable physical properties over a period of 1000 years. This paper presents the approach for performing accelerated aging tests and evaluating the performance of samples under accelerated conditions. The results of these tests will be compared with asphalt artifact analogs and the results of modeling the degradation of the selected asphalt composite to make life-cycle predictions

  10. Hanford Permanent Isolation Barrier Program: Asphalt technology development

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, H.D.; Romine, R.A.

    1994-11-01

    An important component of the Hanford Permanent Isolation Barrier is the use of a two-layer composite asphalt system, which provides backup water diversion capabilities if the primary capillary barrier fails to meet infiltration goals. Because of asphalt`s potential to perform to specification over the 1000-year design life criterion, a composite asphalt barrier (HMAC/fluid-applied polymer-modified asphalt) is being considered as an alternative to the bentonite clay/high density poly(ethylene) barriers for the low-permeability component of the Hanford Permanent Isolation Barrier. The feasibility of using asphalt as a long-term barrier is currently being studied. Information that must be known is the ability of asphalt to retain desirable physical properties over a period of 1000 years. This paper presents the approach for performing accelerated aging tests and evaluating the performance of samples under accelerated conditions. The results of these tests will be compared with asphalt artifact analogs and the results of modeling the degradation of the selected asphalt composite to make life-cycle predictions.

  11. CFD simulation and optimization of the capillary throttling of air-flotation unit

    Science.gov (United States)

    Bin, Huang; Yi, Jiajing; Tao, Jiayue; Lu, Rongsheng

    2016-01-01

    With respect to orifice throttling or compensating, capillary throttling has following advantages: smaller mass flow rate and stronger anti-interference ability. This paper firstly gives the required average pressure of air-film when shipping a piece of LCD glass. Then, dimensional flow model of the capillary throttling of air-flotation unit is established. Based on the model, we firstly analyze the flowing process of the lubricated air through the capillary. Secondly, the pressure distribution equation of air-film is derived from the Navier-Stokes Equation. Furthermore, the approximate functional relations between model parameters and static characteristics of the air-film, such as mass flow rate, static bearing capacity, are obtained and then influence of the former on the latter is analyzed . Finally, according to the continuity of air flow, the function relation between model parameters and pressure of core nodes in the air-film is also derived. On foundation of theoretical analysis, the impacts of each model parameter on static characteristics of the air-film flow field, are respectively simulated and analyzed by CFD software Fluent. Based on these simulations and analysis, radius and length of the capillary, density of the gas supply orifices and other model parameters are optimized. Finally, the best unit model is acquired, which greatly improves the static working performance of air-film in air-flotation unit. Research results of this paper can provide guidance and basis for the design and optimization of air-flotation transporting system.

  12. A new post-column reactor-laser induced fluorescence detector for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Liling

    1996-01-02

    Capillary zone electrophoresis (CZE), a powerful separation method based on the differential migration of charged species under the influence of an electric field, has been widely used for separations covering from small ions to big biomolecules. Chapter 1 describes the method, then discusses detection of the separated analytes by laser induced fluorescence and by chemical derivatization, and the use of O-phthaldialdehyde (OPA) as a post-column reagent. Chapter 2 describes a post-column reactor which uses two narrow bore capillaries connected coaxially. This reactor differs from other coaxial reactors in terms of capillary dimensions, reagent flow control, ease of construction and most importantly, better limits of detection. The derivatization reagent is electroosmotically driven into the reaction capillary and the reagent flow rate is independently controlled by a high voltage power supply. Amino acids, amines and proteins, derivatized by OPA/2-mercaptoethanol using this post-column reactor coupled with LIF detection, show low attomole mass limits of detection, and for the first time, the authors demonstrate single cell capability with a post-column derivatization scheme. The single cell capability shows that this reactor could find applications in assaying non-fluorescent or electrochemically inactive components in individual biological cells in the future.

  13. Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Zhao, Xiangwei; Xue, Jiangyang; Mu, Zhongde; Huang, Yin; Lu, Meng; Gu, Zhongze

    2015-10-15

    Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9 mg/dL.

  14. Recent advances in the analysis of therapeutic proteins by capillary and microchip electrophoresis.

    Science.gov (United States)

    Creamer, Jessica S; Oborny, Nathan J; Lunte, Susan M

    2014-07-01

    The development of therapeutic proteins and peptides is an expensive and time-intensive process. Biologics, which have become a multi-billion dollar industry, are chemically complex products that require constant observation during each stage of development and production. Post-translational modifications along with chemical and physical degradation from oxidation, deamidation, and aggregation, lead to high levels of heterogeneity that affect drug quality and efficacy. The various separation modes of capillary electrophoresis (CE) are commonly utilized to perform quality control and assess protein heterogeneity. This review attempts to highlight the most recent developments and applications of CE separation techniques for the characterization of protein and peptide therapeutics by focusing on papers accepted for publication in the in the two-year period between January 2012 and December 2013. The separation principles and technological advances of CE, capillary gel electrophoresis, capillary isoelectric focusing, capillary electrochromatography and CE-mass spectrometry are discussed, along with exciting new applications of these techniques to relevant pharmaceutical issues. Also included is a small selection of papers on microchip electrophoresis to show the direction this field is moving with regards to the development of inexpensive and portable analysis systems for on-site, high-throughput analysis.

  15. Spatial and temporal variations of a sodium fluoride capillary discharge plasma

    International Nuclear Information System (INIS)

    A capillary discharge plasma has been developed and fielded on the Gamble II pulsed power generator for producing an intense source of the He-like sodium resonance line for matched line photopumping of He-like neon. The sodium implosions have produced up to 25 GW of power from the 1.13 keV line of interest. Since the implosion dynamics depend on the linear mass density of the z-pinch, further investigation of the sodium source has been carried out to determine the axial and radial variations of the source. The plasma was produced by discharging a 1.8 μf capacitor bank charged to 25 kV through a 0.021 inch diameter capillary drilled in packed sodium fluoride powder. The powder was heat by the electrical discharge and subsequently ejected from the capillary into an anodized aluminum nozzle which restricted expansion of the plasma and directed it into a cylindrical column. A peak current of about 50 kA was delivered to the capillary in about 1 μs

  16. Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Zhao, Xiangwei; Xue, Jiangyang; Mu, Zhongde; Huang, Yin; Lu, Meng; Gu, Zhongze

    2015-10-15

    Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9 mg/dL. PMID:25988995

  17. An axial approach to detection in capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.A.

    1993-05-01

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

  18. Capillary remodeling in bleomycin-induced pulmonary fibrosis.

    OpenAIRE

    Schraufnagel, D. E.; Mehta, D.; Harshbarger, R.; Treviranus, K.; Wang, N. S.

    1986-01-01

    Lung fibrosis is a process in which collagen is laid down and the delicate capillary-alveolar relationship is disturbed. The architectural changes which occur in the capillaries, a main element of the oxygen transferring unit, are difficult to illustrate without a three-dimensional tool, such as scanning electron microscopy. Therefore, a scanning electron microscopic study was undertaken to show the capillary changes of lung fibrosis. Fibrosis was induced in rats by intratracheal instillation...

  19. Nicked-sleeve interface for two-dimensional capillary electrophoresis

    OpenAIRE

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

    2013-01-01

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

  20. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    Wei Chang; Tusyo-shi Komazu

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva, the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic silica capillary when it was used to concentrate catecholamines.

  1. Catalytic thermal barrier coatings

    Science.gov (United States)

    Kulkarni, Anand A.; Campbell, Christian X.; Subramanian, Ramesh

    2009-06-02

    A catalyst element (30) for high temperature applications such as a gas turbine engine. The catalyst element includes a metal substrate such as a tube (32) having a layer of ceramic thermal barrier coating material (34) disposed on the substrate for thermally insulating the metal substrate from a high temperature fuel/air mixture. The ceramic thermal barrier coating material is formed of a crystal structure populated with base elements but with selected sites of the crystal structure being populated by substitute ions selected to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a higher rate than would the base compound without the ionic substitutions. Precious metal crystallites may be disposed within the crystal structure to allow the ceramic thermal barrier coating material to catalytically react the fuel-air mixture at a lower light-off temperature than would the ceramic thermal barrier coating material without the precious metal crystallites.

  2. High Performance Wafer-Based Capillary Electrochromatography Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II research comprises designing, constructing, and testing a chip-based capillary electrochromatography (CEC) prototype for separation and analysis of...

  3. A Prediction Model of the Capillary Pressure J-Function

    Science.gov (United States)

    Xu, W. S.; Luo, P. Y.; Sun, L.; Lin, N.

    2016-01-01

    The capillary pressure J-function is a dimensionless measure of the capillary pressure of a fluid in a porous medium. The function was derived based on a capillary bundle model. However, the dependence of the J-function on the saturation Sw is not well understood. A prediction model for it is presented based on capillary pressure model, and the J-function prediction model is a power function instead of an exponential or polynomial function. Relative permeability is calculated with the J-function prediction model, resulting in an easier calculation and results that are more representative. PMID:27603701

  4. Novel Micro-Capillary Electrochromatography for Mars Organic Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a powerful new technology - next generation Micro-Capillary Electrochromatography ? a high performance and low power...

  5. Capillary-Condenser-Pumped Heat-Transfer Loop

    Science.gov (United States)

    Silverstein, Calvin C.

    1989-01-01

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

  6. Capillary Micro-Flow Through a Fiber Bundle(Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying-dan; WANG Ji-hui; TAN Hua; GAO Guo-qiang

    2004-01-01

    The present work considered the capillary micro-flow through a fiber bundle. The resin heights in the fiber bundle as a function of time were used to determine the experimental values of capillary pressure and the permeability by the nonlinear regression fitting method. The fitting curves showed a good agreement with experiments. However, these values of capillary pressure from short- time experiments were much lower than the theoretical results from the Yang-Laplace Equation. More accurate capillary pressure was predicted from the presented long-run experiment.

  7. Novel Micro-Capillary Electrochromatography for Mars Organic Detector Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a powerful new technology - next generation Micro-Capillary Electrochromatography - a high performance and low power...

  8. Capillary pericytes regulate cerebral blood flow in health and disease

    DEFF Research Database (Denmark)

    Hall, Catherine N; Reynell, Clare; Gesslein, Bodil;

    2014-01-01

    Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate...... blood flow, capillaries dilate before arterioles and are estimated to produce 84% of the blood flow increase. In pathology, ischaemia evokes capillary constriction by pericytes. We show that this is followed by pericyte death in rigor, which may irreversibly constrict capillaries and damage the blood-brain...

  9. Determination of chlorophenols in environmental samples using electromembrane extraction and capillary electrophoresis

    OpenAIRE

    Šlampová, Andrea

    2013-01-01

    Combination of electromembrane extraction (EME) with capillary electrophoresis (CE) was used for determination of trace level chlorophenols (CPs) in environmental water samples. The analytes were transported across supported liquid membrane (SLM), composed of 1-ethyl-2-nitrobenzene (ENB), by the application of electrical field. A driving force of 150 V was applied to extract the analytes from neutral sample (donor solution) into strongly alkaline acceptor solutions. The acceptor soluti...

  10. Analysis of Endocrine Disrupting Pesticides by Capillary GC with Mass Spectrometric Detection

    OpenAIRE

    Svetlana Hrouzková; Eva Matisová

    2012-01-01

    Endocrine disrupting chemicals, among them many pesticides, alter the normal functioning of the endocrine system of both wildlife and humans at very low concentration levels. Therefore, the importance of method development for their analysis in food and the environment is increasing. This also covers contributions in the field of ultra-trace analysis of multicomponent mixtures of organic pollutants in complex matrices. With this fact conventional capillary gas chromatography (CGC) and fast CG...

  11. Guided transmission of 3 keV Ne sup 7 sup + ions through nanocapillaries in PET polymers. Dependence on the capillary diameter

    CERN Document Server

    Stolterfoht, N; Pesic, Z D; Hoffmann, V; Petrov, S; Fink, D; Sulik, B

    2003-01-01

    The outstanding progress in nanotechnology is accompanied by a continuous miniaturization of interfaces used in microelectronics and related fields. Particular attention has been paid to linear structures of mesoscopic dimensions, such as pores or capillaries. Experiments were started in which PET (Mylar) polymer foils of 10 lm thickness were irradiated by 400 MeV xenon. Capillaries with a diameter of a few hundreds nm in foil were obtained etching ion tracks using NaOH. (R.P.)

  12. Electroviscous effects in capillary filling of nanochannels

    DEFF Research Database (Denmark)

    Mortensen, Asger; Kristensen, Anders

    2008-01-01

    maximum in the mesoscopic regime where the channel height (or more generally the hydraulic radius) is comparable to the screening length. However, for realistic estimates of central parameters, we find that the electroviscous contribution to the apparent viscosity is at most a 1% effect.......We theoretically examine the widespread hypothesis of an electroviscous origin of the increase in apparent viscosity observed in recent experiments on capillary filling of nanochannels. Including Debye-layer corrections to the hydraulic resistance, we find that the apparent viscosity reaches a...

  13. Capillary-Pumped Heat-Transfer Loop

    Science.gov (United States)

    1989-01-01

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

  14. Capillary Network, Cancer and Kleiber Law

    CERN Document Server

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

    2014-01-01

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

  15. Experimental study on capillary filling in nanochannels

    Science.gov (United States)

    Yang, Min; Cao, Bing-Yang; Wang, Wei; Yun, He-Ming; Chen, Bao-Ming

    2016-10-01

    We investigated the capillary filling kinetics of deionized water in nanochannels with heights of 50-120 nm. The measured position of the moving meniscus was proportional to the square root of time, as predicted by the LW equation. However, the extracted slopes were significantly smaller than the predictions based on the bulk properties. This unusual behavior was found to be mainly caused by the electro-viscous effect and dynamic contact angle, which was significantly larger than the static angle. In addition, when the filling distance reached about 600 μm, bubbles tended to be formed, leading to the main meniscus was almost immobile.

  16. Capillary zone electrophoresis and packed capillary column liquid chromatographic analysis of recombinant human interleukin-4.

    Science.gov (United States)

    Bullock, J

    1993-02-24

    Capillary zone electrophoresis (CZE) and packed capillary column liquid chromatography (micro-LC) have been applied to the analysis of the recombinant human protein interleukin-4 (rhIL-4). Separations for both the parent protein and its enzymatic digest were developed for the purpose of characterizing protein purity and identity. CZE separations of the intact protein were investigated over the pH range of 4.5 to 8.0 using uncoated fused silica capillaries. Gradient reversed-phase micro-LC was performed using 0.32 mm packed capillary columns at flow-rates of 5-6 microliters/min. Emphasis was placed on the ability of these methods to separate close structural variants and degradation products of the protein. Peptide mapping of the tryptic digest of rhIL-4 using a combination of CZE and micro-LC provided complimentary high resolution methods for establishing protein identity. Reproducible separations were achieved using sub-picomol amounts of sample. The advantages and problems encountered with these two techniques for characterizing rhIL-4 were assessed. PMID:8450025

  17. Capacitively coupled contactless conductivity detection and sequential injection analysis in capillary electrophoresis and capillary electro-chromatography

    OpenAIRE

    Mai, Thanh Duc

    2011-01-01

    This thesis focuses on the applications of capacitively coupled contactless conductivity detection (C4D) in capillary electrophoresis (CE) hybridized with high-performance liquid chromatography (HPLC), i.e. in capillary electrochromatography and pressure-assisted capillary electrophoresis, as well as on the development and applications of an extension of CE-C4D with sequential injection analysis (SIA). At first, the in-house built C4D was used for electro-chromatographic determinations of...

  18. PLASMA-field barrier sentry (PFBS)

    Science.gov (United States)

    Gonzaga, Ernesto A.; Cossette, Harold James

    2013-06-01

    This paper describes the concept and method in designing and developing a unique security system apparatus that will counter unauthorized personnel: to deny access to or occupy an area or facility, to control or direct crowd or large groups, and to incapacitate individuals or small groups until they can be secured by military or law enforcement personnel. The system exploits Tesla coil technology. Application of basic engineering circuit analysis and principle is demonstrated. Transformation from classical spark gap method to modern solid state design was presented. The analysis shows how the optimum design can be implemented to maximize performance of the apparatus. Discussion of the hazardous effects of electrical elements to human physiological conditions was covered. This serves to define guidelines in implementing safety limits and precautions on the performance of the system. The project is strictly adhering towards non-lethal technologies and systems.

  19. Economic analysis of engineered sorbent barrier technology

    International Nuclear Information System (INIS)

    This paper evaluates the incremental cost of placing an engineered sorbent barrier beneath a shallow land burial (SLB) site in a humid climate. The cost estimates are also applicable to alternative uses of sorbent barrier technology such as redundant barriers around below-grade vaults. The preliminary costs presented represent only rough order-of-magnitude estimates. Further information obtained from field studies and refined performance models would allow a more precise cost estimate to be prepared. Flow-through column tests have shown that clinoptilolite is much more effective in sorbing strontium than indicated previously. The effectiveness of the barrier for cobalt was not as good as that measured previously. The costs in this paper are based on these updated data. 8 refs., 1 fig., 4 tabs

  20. Nucleation barrier height in undercooled metallic melts

    Institute of Scientific and Technical Information of China (English)

    Gang WANG; Dechang ZENG; Zhongwu LIU

    2012-01-01

    The phase-field model of a liquid-to-solid transition was constructed where the model parameters were linked quantitatively to the interfacial properties,and the variation of nucleation barrier height in undercooled metallic melts with respect to undercooling was studied respectively based on two kinds of forms of local free energy density.The calculation results show that,with the increase of undercooling,the critical nucleus does not show bulk properties,and the nucleation barrier height decreases gradually and deviates more and more from that predicted by the classical nucleation theory in both cases.The physical spinodal occurs for a specific form of the local free energy density,where the nucleation barrier height vanishes when the undercooling reaches a critical value and the reduced nucleation barrier height can be expressed by a function of the ratio of undercooling to critical undercooling.

  1. Mechanism of Striation in Dielectric Barrier Discharge

    Institute of Scientific and Technical Information of China (English)

    FENG Shuo; HE Feng; OUYANG Ji-Ting

    2007-01-01

    @@ The mechanism of striations in dielectric barrier discharge in pure neon is studied by a two-dimensional particlein-cell/Monte Carlo collision (PIC-MCC) model. It is shown that the striations appear in the plasma background,and non-uniform electrical field resulting from ionization and the negative wall charge appear on the dielectric layer above the anode. The sustainment of striations is a non-local kinetic effect of electrons in a stratified field controlled by non-elastic impact with neutral gases. The striations in the transient dielectric barrier discharge are similar to those in dc positive column discharge.

  2. Complementary barrier infrared detector (CBIRD)

    Science.gov (United States)

    Ting, David Z. (Inventor); Bandara, Sumith V. (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

    2013-01-01

    An infrared detector having a hole barrier region adjacent to one side of an absorber region, an electron barrier region adjacent to the other side of the absorber region, and a semiconductor adjacent to the electron barrier.

  3. 直线形围栏陷阱系统对玉米地鼠情的监测效果%Monitoring rodents with linear trap-barrier system in corn fields

    Institute of Scientific and Technical Information of China (English)

    戴爱梅; 欧阳春华; 郭永旺; 赵志强; 古丽扎提

    2016-01-01

    AbstractThe trap-barrier system (TBS) method has been used extensively in agricultural systems for trapping rodents in China because it is highly effective in preventing and controlling rodents with high capture rate, long and consistent control period and poses no harm to people and livestock as well as predators. Many researchers also have recommended the use of TBS in monitoring rodents due to its ability to capture rodents. In order to test the effects of TBS rodent monitoring, we set line trap-barrier system (L-TBS) and night snap-trap (NST, national industry standard of NY/T 1481—2007 ) systems from May to October 2015 to trap rodents in the corn fields of Boertala Mongolia Autonomous County, Xinjiang Uygur Autonomous Region. The purpose of this study was to investigate the scientific evidence of the application of L-TBS in field rodent surveillance and to explore the corresponding relations between rodent community collected by L-TBS and by NST. Three replications were carried out at different sites in the same region using the same operation mode. The rodent community structure and population structure of dominant rodent species, including population dynamics and reproduction characteristics of captured rodent species were analyzed. The results certified the relevance of rodent species, and population structure and reproduction characters of rodent community between two methods. Firstly, Chi-Square test on rodent species composition captured by the L-TBS and NTS showed no statistically significant differences (χ2= 3.31,P= 0.35). The percentage of dominant species of rodent composition was also not statistically significantly different (Mus musculus:χ2= 1.50,P= 0.44;Cricetulus migratorius:χ2= 0.54,P= 0.63). Secondly, there was a statistically significant positive correlation between the abundance of the dominant species house mouse (Mus musculus) captured by L-TBS and NST (y= 0.143 1 + 0.146 5x,r= 0.707 7,P= 0.000 0). Meanwhile, the reproduction

  4. Converse Barrier Certificate Theorem

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer

    2013-01-01

    This paper presents a converse barrier certificate theorem for a generic dynamical system.We show that a barrier certificate exists for any safe dynamical system defined on a compact manifold. Other authors have developed a related result, by assuming that the dynamical system has no singular...... points in the considered subset of the state space. In this paper, we redefine the standard notion of safety to comply with generic dynamical systems with multiple singularities. Afterwards, we prove the converse barrier certificate theorem and illustrate the differences between ours and previous work by...

  5. Recycler barrier RF buckets

    CERN Document Server

    Bhat, C M

    2012-01-01

    The Recycler Ring at Fermilab uses a barrier rf system for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf systems, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  6. Recycler barrier RF buckets

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab

    2011-03-01

    The Recycler Ring at Fermilab uses a barrier rf systems for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf system, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  7. Electroosmotic flow phenomena in packed capillaries: From the interstitial velocities to intraparticle and boundary layer mass transfer

    NARCIS (Netherlands)

    Tallarek, U.; Rapp, E.; Seidel-Morgenstern, A.; As, van H.

    2002-01-01

    Pulsed field gradient nuclear magnetic resonance studies of electrokinetic flow through a 250 m i.d. cylindrical fused-silica capillary packed with spherical porous particles (dp = 41 m) have revealed the following phenomena and parameters: (i) An electrokinetic wall effect exists due to a mismatch

  8. Critical Velocity in Open Capillary Channel Flows

    Science.gov (United States)

    Rosendahl, Uwe; Dreyer, Michael E.; Rath, Hans J.; Motil, Brian; Singh, Bhim S. (Technical Monitor)

    2001-01-01

    We investigate forced liquid flows through open capillary channels with free surfaces experimentally. The experiments were performed under low gravity conditions in the Bremen Drop Tower and on board the sounding rocket TEXUS-37. Open capillary channels (vanes) are used in surface tension tanks to transport the propellant and to provide a flow path for the bubble-free liquid supply to the thrusters. Since the free surfaces can only withstand a certain pressure differential between the liquid and ambient, the flow rate in the channel is limited. The maximum flow rate is achieved when the surfaces collapse and gas is ingested into the outlet. Since experimental and theoretical data of this flow rate limitation is lacking, the safety factors for the application of vanes in surface tension tanks must be unnecessary high. The aim of the investigation is to determine the maximum liquid flow rate and the corresponding critical flow velocity. The characteristic nondimensional parameters, OHNESORGE number, and gap ratio, cover a wide range of usual vanes. For the theoretical approach a one-dimensional momentum balance was set up. The numerical solution yields the maximum volume flux and the position of the free surface in good agreement with the experiments.

  9. CMOS absorbance detection system for capillary electrophoresis

    International Nuclear Information System (INIS)

    This paper presents a cost-effective portable photodetection system for capillary electrophoresis absorptiometry. By using a CMOS BDJ (buried double p-n junction) detector, a dual-wavelength method for absorbance measurement is implemented. This system includes associated electronics for low-noise pre-amplification and A/D conversion, followed by digital signal acquisition and processing. Two signal processing approaches are adopted to enhance the signal to noise ratio. One is variable time synchronous detection, which optimizes the sensitivity and measuring rate compared to a conventional synchronous detection technique. The other is a statistical approach based on principal component analysis, which allows optimal estimation of detected signal. This system has been designed and tested in capillary electrophoresis conditions. Its operation has been verified with performances comparable to those of a commercialized spectrophotometric system (HP-3D CE). With potential on-chip integration of associated electronics, it may be operated as an integrable detection module for microchip electrophoresis and other microanalysis systems

  10. Capillary wrinkling of thin bilayer polymeric sheets

    Science.gov (United States)

    Chang, Jooyoung; Menon, Narayanan; Russell, Thomas

    We have investigated capillary force induced wrinkling on a floated polymeric bilayer thin sheet. The origin of the wrinkle pattern is compressional hoop stress caused by the capillary force of a water droplet placed on the floated polymeric thin sheet afore investigated. Herein, we study the effect of the differences of surface energy arising from the hydrophobicity of Polystyrene (PS Mw: 97 K, Contact Angle: 88 º) and the hydrophilicity of Poly(methylmethacrylate) (PMMA Mw: 99K, Contact Angle: 68 º) on two sides of a bilayer film. We measure the number and the length of the wrinkles by broadly varying the range of thicknesses of top (9 nm to 550 nm) and bottom layer (25 nm to 330 nm). At the same, there is only a small contrast in mechanical properties of the two layers (PS E = 3.4 GPa, and PMMA E = 3 GPa). The number of the wrinkles is not strongly affected by the composition (PS(Top)/PMMA(Bottom) or PMMA(Top)/PS(Bottom)) and the thickness of each and overall bilayer system. However, the length of the wrinkle is governed by the contact angle of the drop on the top layer of bilayer system. We also compare this to the wrinkle pattern obtained in monolayer systems over a wide range of thickness from PS and PMMA (7 nm to 1 μm). W.M. Keck Foundation.

  11. Using capillary electrophoresis to characterize polymeric particles.

    Science.gov (United States)

    Riley, Kathryn R; Liu, Sophia; Yu, Guo; Libby, Kara; Cubicciotti, Roger; Colyer, Christa L

    2016-09-01

    Capillary electrophoresis (CE) was used for the characterization of a variety of polymeric micron and sub-micron particles based on size, surface functionality, and binding properties. First, a robust capillary zone electrophoresis (CZE) method was developed for the baseline separation and quantitation of commercially available polystyrene particles with various surface modifications (including amino, carboxylate, and sulfate functional groups) and various sizes (0.2, 0.5, 1.0, and 3.0μm). The separation of DNA-templated polyacrylamide particles from untemplated particles (as used for the Ion Torrent Personal Genome Machine) was demonstrated. Finally, using the 29-base thrombin aptamer and thrombin protein as a model system, a study was undertaken to determine dissociation constants for the aptamer and protein in free solution and when the aptamer was conjugated to a particle, with the goal of better understanding how the use of solid substrates, like particles, affects selection and binding processes. Dissociation constants were determined and were found to be approximately 5-fold higher for the aptamer conjugated to a particle relative to that in free solution. PMID:27543386

  12. Flow and deformation of the capillary glycocalyx in the wake of a leukocyte

    Science.gov (United States)

    Damiano, Edward R.; Stace, Thomas M.

    2005-03-01

    An analysis is presented of the axisymmetric axial and radial flow and deformation fields throughout the endothelial-cell glycocalyx surface layer in the wake region behind a leukocyte moving steadily through a capillary. The glycocalyx, modeled as a thin poroelastic surface layer lining the capillary wall, is assumed to consist of a binary mixture of a linearly viscous fluid constituent and an isotropic, highly compressible, linearly elastic solid constituent having a vanishingly small solid-volume fraction. Invoking the asymptotic approximations of lubrication theory in a frame of reference translating with the leukocyte, closed-form solutions are obtained to the leading-order boundary-value problems governing the axial and radial flow and deformation fields throughout the glycocalyx as well as the axial and radial flow fields throughout the free capillary lumen within the wake. A simple asymptotic expression is obtained for the length lchar of the wake region in terms of the translational speed U0 of the leukocyte, and the equilibrium thickness h0, permeability k0, and aggregate elastic modulus HA of the glycocalyx. The predicted wake length, as seen from an observer moving in a reference frame attached to the leukocyte, is consistent with the recovery time predicted from a one-dimensional analysis of glycocalyx deformation through a quiescent inviscid fluid. The two-dimensional fluid dynamical analysis presented here thus provides the appropriate relationships for extracting estimates of the mechanoelectrochemical properties of the glycocalyx from physiologically realistic constitutive models developed under simplified one-dimensional flow regimes. The directly measurable quantities lchar,U0, and h0, which are obtainable from in vivo observations of the wake region behind a leukocyte moving steadily through a capillary, can therefore be connected, through the results of this analysis, to estimates of the mechanoelectrochemical properties of the glycocalyx on

  13. A Simple Double-Source Model for Interference of Capillaries

    Science.gov (United States)

    Hou, Zhibo; Zhao, Xiaohong; Xiao, Jinghua

    2012-01-01

    A simple but physically intuitive double-source model is proposed to explain the interferogram of a laser-capillary system, where two effective virtual sources are used to describe the rays reflected by and transmitted through the capillary. The locations of the two virtual sources are functions of the observing positions on the target screen. An…

  14. Soft x-ray amplification in an ablative capillary discharge

    International Nuclear Information System (INIS)

    Soft x-ray amplification in CVI 18.2 nm line is observed in an ablative UHMW-PE capillary discharge. The gain coefficient is measured to be 1.9 cm-1. The electron density is about 2 x 1019 cm-3. This indicates that capillary discharge pumping device can be a source for a compact soft x-ray laser. (author)

  15. Potential of capillary electrophoresis for the profiling of propolis

    NARCIS (Netherlands)

    Hilhorst, M.J; Somsen, G.W; de Jong, G.J.

    1998-01-01

    The usefulness of capillary electrophoresis (CE) with diode array detection for the profiling of Propolis, a hive product, is investigated. Water extracts of Propolis were analyzed with both capillary zone electrophoresis (CZE) at pH 7.0 and 9.3, and micellar electrokinetic chromatography (MEKC) wit

  16. Analysis of organic acids in Macedonian wines by capillary electrophoresis

    OpenAIRE

    Jancovska, Maja; Ivanova, Violeta; Gulaboski, Rubin; Belder, Detlev

    2013-01-01

    Capillary electrophoresis as a separation technique can be applied for analysis of organic acids in white and red wines, providing high resolution separation of the analytes. Organic acids such as of tartaric, malic, lactic citric and succinic acids have been analysed in many Macedonian red and white wines by capillary electrophoresis, and results have been discussed.

  17. Blepharospasm in a patient with pontine capillary telangiectasia

    OpenAIRE

    Gilbert, AL; Dillon, WP; Horton, JC

    2012-01-01

    Blepharospasm is rarely due to an identifiable etiology. In the majority of cases, imaging fails to reveal any structural lesion. Here we describe an otherwise healthy patient with blepharospasm who was found to have pontine capillary telangiectasia. We propose a potential association between blepharospasm and pontine capillary telangiectasia. © 2012 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.

  18. Hydrological modeling to assess capillary rise contribution to satisfy crop water requirement and groundwater recharge

    Science.gov (United States)

    Wassar, Fatma; Gandolfi, Claudio; chiaradia, Enrico Antonio

    2016-04-01

    lower than the total downward flow to the groundwater table. According to IDRAGRA simulation and for both seasons, there was not a real recharge to the water table for a groundwater table depth lower than 2m. While for SWAP model, the net recharge exist even under shallower water table and that can be attributed to the higher deep percolation estimated with the same model. During 2011 season, the recharge was negligible due to the lowest amount of rain that occurred during the same period. The analysis of groundwater recharge and capillary rise processes will be useful in increasing field irrigation efficiency, improving the accuracy of groundwater modeling by reducing uncertainties, and making relevant management decisions in Lombardy region. Keywords: Hydrological model, capillary rise, groundwater recharge, groundwater table contribution, crop water requirement, maize

  19. [Vascular endothelial Barrier Function].

    Science.gov (United States)

    Ivanov, A N; Puchinyan, D M; Norkin, I A

    2015-01-01

    Endothelium is an important regulator of selective permeability of the vascular wall for different molecules and cells. This review summarizes current data on endothelial barrier function. Endothelial glycocalyx structure, its function and role in the molecular transport and leukocytes migration across the endothelial barrier are discussed. The mechanisms of transcellular transport of macromolecules and cell migration through endothelial cells are reviewed. Special section of this article addresses the structure and function of tight and adherens endothelial junction, as well as their importance for the regulation of paracellular transport across the endothelial barrier. Particular attention is paid to the signaling mechanism of endothelial barrier function regulation and the factors that influence on the vascular permeability.

  20. Barriers to Effective Listening.

    Science.gov (United States)

    Hulbert, Jack E.

    1989-01-01

    Discusses the following barriers which interfere with listening efficiency: content, speaker, medium, distractions, mindset, language, listening speed, and feedback. Suggests ways to combat these obstacles to accurate comprehension. (MM)

  1. Overcoming Intercultural Communication Barriers.

    Science.gov (United States)

    Hulbert, Jack E.

    1994-01-01

    Describes an activity that helps students overcome the multicultural barriers that might be encountered in dealing with people from various cultures in a global economy. Outlines instructions, reporting procedures, principles to emphasize, and time required for the exercise. (HB)

  2. Information barriers and authentication

    International Nuclear Information System (INIS)

    Acceptance of nuclear materials into a monitoring regime is complicated if the materials are in classified shapes or have classified composition. An attribute measurement system with an information barrier can be emplo,yed to generate an unclassified display from classified measurements. This information barrier must meet two criteria: (1) classified information cannot be released to the monitoring party, and (2) the monitoring party must be convinced that the unclassified output accurately represents the classified input. Criterion 1 is critical to the host country to protect the classified information. Criterion 2 is critical to the monitoring party and is often termed the 'authentication problem.' Thus, the necessity for authentication of a measurement system with an information barrier stems directly from the description of a useful information barrier. Authentication issues must be continually addressed during the entire development lifecycle of the measurement system as opposed to being applied only after the system is built.

  3. Interactions of inhaled nanoparticles with the alveolar-capillary barrier of the human respiratory tract

    OpenAIRE

    Kasper, Jennifer Yvonne

    2011-01-01

    In dieser Arbeit wurden zytotoxische Effekte sowie die inflammatorische Reaktionen des distalen respiratorischen Traktes nach Nanopartikelexposition untersucht. Besondere Aufmerksamkeit lag auch auf der Untersuchung unterschiedlicher zellulärer Aufnahmewege von Nanopartikeln wie z.B. Clathrin- oder Caveolae-vermittelte Endozytose oder auch Clathrin- und Caveolae-unabhängige Endozytose (mit möglicher Beteiligung von Flotillinen). Drei unterschiedliche Nanopartikel wurden hierbei gewählt: amo...

  4. Pore capillary pressure and saturation of methane hydrate bearing sediments

    Institute of Scientific and Technical Information of China (English)

    SUN Shicai; LIU Changling; YE Yuguang; LIU Yufeng

    2014-01-01

    To better understand the relationship between the pore capillary pressure and hydrate saturation in sedi-ments, a new method was proposed. First, the phase equilibria of methane hydrate in fine-grained silica sands were measured. As to the equilibrium data, the pore capillary pressure and saturation of methane hydrate were calculated. The results showed that the phase equilibria of methane hydrates in fine-grained silica sands changed due to the depressed activity of pore water caused by the surface group and negatively charged characteristic of silica particles as well as the capillary pressure in small pores together. The capil-lary pressure increased with the increase of methane hydrate saturation due to the decrease of the available pore space. However, the capillary-saturation relationship could not yet be described quantitatively because of the stochastic habit of hydrate growth.

  5. Capillary zone electrophoresis analysis and detection of mid-spectrum biological warfare agents

    Energy Technology Data Exchange (ETDEWEB)

    Boulet, C.A.; Townsley, C.

    1995-04-01

    DRE Suffield has initiated a research program to develop methods and equipment for field detection and laboratory identification of mid-spectrum agents, molecules of biological origin such as proteins, peptides and toxins. In this study, a highly efficient and reproducible capillary zone electrophoresis method was developed to separate and identify a series of nine peptides of defence interest: bradykinin, bradykinin fragment 1-5, substance P,ARG8-vasopressin, luteinizing hormone releasing hormone, bombesin, leucine enkephalin, methionine enkephalin, and oxytocin. Using a 50 micrometer x 47 cm capillary column, 22.5 kV separation voltage and a 100 mM pH 2.5 phosphate buffer, all nine peptide could separated in under 10 minutes. Three strategies, which could be used in a fully automated field detection and identification system, were demonstrated for the identification of unknown peptides: comparison of migration times, comparison of electrophoretic mobilities, and co-injection of multiple reference standards. These experiments demonstrate that a separation based analytical method such as capillary electrophoresis could form the basis of a generic detection system for mid-spectrum protein and peptide toxins.

  6. Electrochemical methods in conjunction with capillary and microchip electrophoresis.

    Science.gov (United States)

    Mark, Jonas J P; Scholz, Rebekka; Matysik, Frank-Michael

    2012-12-01

    Electromigrative techniques such as capillary and microchip electrophoresis (CE and MCE) are inherently associated with various electrochemical phenomena. The electrolytic processes occurring in the buffer reservoirs have to be considered for a proper design of miniaturized electrophoretic systems and a suitable selection of buffer composition. In addition, the control of the electroosmotic flow plays a crucial role for the optimization of CE/MCE separations. Electroanalytical methods have significant importance in the field of detection in conjunction with CE/MCE. At present, amperometric detection and contactless conductivity detection are the predominating electrochemical detection methods for CE/MCE. This paper reviews the most recent trends in the field of electrochemical detection coupled to CE/MCE. The emphasis is on methodical developments and new applications that have been published over the past five years. A rather new way for the implementation of electrochemical methods into CE systems is the concept of electrochemically assisted injection which involves the electrochemical conversions of analytes during the injection step. This approach is particularly attractive in hyphenation to mass spectrometry (MS) as it widens the range of CE-MS applications. An overview of recent developments of electrochemically assisted injection coupled to CE is presented.

  7. Thermal-capillary model for Czochralski growth of semiconductor materials

    Science.gov (United States)

    Derby, J. J.; Brown, R. A.

    1985-01-01

    The success of efficiently calculating the temperature field, crystal radius, melt mensicus, and melt/solid interface in the Czochralski crystal growth system by full finite-element solution of the government thermal-capillary model is demonstrated. The model predicts realistic response to changes in pull rate, melt volume, and the thermal field. The experimentally observed phenomena of interface flipping, bumping, and the difficulty maintaining steady-state growth as the melt depth decreases are explained by model results. These calculations will form the basis for the first quantitative picture of Cz crystal growth. The accurate depiction of the melt meniscus is important in calculating the crystal radius and solidification interface. The sensitivity of the results to the equilibrium growth angle place doubt on less sophisticated attempts to model the process without inclusion of the meniscus. Quantitative comparison with experiments should be possible once more representation of the radiation and view factors in the thermal system and the crucible are included. Extensions of the model in these directions are underway.

  8. Validation of STR typing by capillary electrophoresis.

    Science.gov (United States)

    Moretti, T R; Baumstark, A L; Defenbaugh, D A; Keys, K M; Brown, A L; Budowle, B

    2001-05-01

    With the use of capillary electrophoresis (CE), high-resolution electrophoretic separation of short tandem repeat (STR) loci can be achieved in a semiautomated fashion. Laser-induced detection of fluorescently labeled PCR products and multicolor analysis enable the rapid generation of multilocus DNA profiles. In this study, conditions for typing PCR-amplified STR loci by capillary electrophoresis were investigated using the ABI Prism 310 Genetic Analyzer (Applied Biosystems). An internal size standard was used with each run to effectively normalize mobility differences among injections. Alleles were designated by comparison to allelic ladders that were run with each sample set. Multiple runs of allelic ladders and of amplified samples demonstrate that allele sizes were reproducible, with standard deviations typically less than 0.12 bases for fragments up to 317 bases in length (largest allele analyzed) separated in a 47 cm capillary. Therefore, 99.7% of all alleles that are the same length should fall within the measurement error window of +/- 0.36 bases. Microvariants of the tetranucleotide repeats were also accurately typed by the analytical software. Alleles differing in size by one base could be resolved in two-donor DNA mixtures in which the minor component comprised > or = 5% of the total DNA. Furthermore, the quantitative data format (i.e., peak amplitude) can in some instances assist in determining individual STR profiles in mixed samples. DNA samples from previously typed cases (typed for RFLP, AmpliType PM+DQA1, and/or D1S80) were amplified using AmpFlSTR Profiler Plus and COfiler and were evaluated using the ABI Prism 310. Most samples yielded typable results. Compared with previously determined results for other loci, there were no discrepancies as to the inclusion or exclusion of suspects or victims. CE thus provides efficient separation, resolution, sensitivity and precision, and the analytical software provides reliable genotyping of STR loci. The

  9. The blood-nerve barrier: structure and functional significance.

    Science.gov (United States)

    Weerasuriya, Ananda; Mizisin, Andrew P

    2011-01-01

    The blood-nerve barrier (BNB) defines the physiological space within which the axons, Schwann cells, and other associated cells of a peripheral nerve function. The BNB consists of the endoneurial microvessels within the nerve fascicle and the investing perineurium. The restricted permeability of these two barriers protects the endoneurial microenvironment from drastic concentration changes in the vascular and other extracellular spaces. It is postulated that endoneurial homeostatic mechanisms regulate the milieu intérieur of peripheral axons and associated Schwann cells. These mechanisms are discussed in relation to nerve development, Wallerian degeneration and nerve regeneration, and lead neuropathy. Finally, the putative factors responsible for the cellular and molecular control of BNB permeability are discussed. Given the dynamic nature of the regulation of the permeability of the perineurium and endoneurial capillaries, it is suggested that the term blood-nerve interface (BNI) better reflects the functional significance of these structures in the maintenance of homeostasis within the endoneurial microenvironment.

  10. Determination of Amino Acids in Single Human Lymphocytes after On-capillary Derivatization by Capillary Zone Electrophoresis with Electrochemical Detection

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Amino acids in individual human lymphocytes were determined by capillary zone electrophoresis with electrochemical detection after on-capillary derivatization. In order to inject cells easily, a cell injector was designed. Four amino acids (serine, alanine, taurine, and glycine) in single human lymphocytes have been identified. Quantitation has been accomplished through the use of calibration curves.

  11. The feasibility of pneumatic and water spray barriers as fireproof oil slick containment devices

    Energy Technology Data Exchange (ETDEWEB)

    Comfort, G.; Menon, B.; Purves, W.

    An Artec Canada, Ltd., project assessed the feasibility of using submerged pneumatic barriers and elevated water spray barriers to retain and concentrate a floating oil slick. Maximum wave, wind, and current conditions at which the barriers were able to operate as oil slick containment devices were measured. Various fluid flow rates and barrier configurations were tested. An examination of data and available literature indicate that, in terms of oil slick containment, the water spray barrier is superior to the pneumatic barrier. The construction and field testing of a prototype water spray barrier system should be initiated. (2 diagrams, 7 graphs, 3 tables)

  12. Capillary-force-induced formation of luminescent polystyrene/(rare-earth-doped nanoparticle) hybrid hollow spheres.

    Science.gov (United States)

    Chen, Min; Xie, Lin; Li, Fuyou; Zhou, Shuxue; Wu, Limin

    2010-10-01

    This paper presents a "one-pot" procedure to synthesize polystyrene/(rare-earth-doped nanoparticles) (PS/REDNPs) hybrid hollow spheres via the in situ diffusion of organic core into inorganic shell under strong capillary force. In this approach, when carboxyl-capped PS colloids were deposited by different REDNPs in aqueous medium, such as LaF3:Eu3+, LaF3:Ce3+-Tb3+, and YVO4:Dy3+, PS/REDNPs inorganic-organic hybrid hollow spheres could be directly obtained via the in situ diffusion of core PS chains into the voids between rare-earth-doped nanoparticles through the strong capillary force. Not only is the synthetic procedure versatile and very simple, but also the obtained hybrid hollow spheres are hydrophilic and luminescent and could be directly used in chemical and biological fields.

  13. Diamond synthesis at atmospheric pressure by microwave capillary plasma chemical vapor deposition

    International Nuclear Information System (INIS)

    Polycrystalline diamond has been synthesized on silicon substrates at atmospheric pressure, using a microwave capillary plasma chemical vapor deposition technique. The CH4/Ar plasma was generated inside of quartz capillary tubes using 2.45 GHz microwave excitation without adding H2 into the deposition gas chemistry. Electronically excited species of CN, C2, Ar, N2, CH, Hβ, and Hα were observed in the emission spectra. Raman measurements of deposited material indicate the formation of well-crystallized diamond, as evidenced by the sharp T2g phonon at 1333 cm−1 peak relative to the Raman features of graphitic carbon. Field emission scanning electron microscopy images reveal that, depending on the growth conditions, the carbon microstructures of grown films exhibit “coral” and “cauliflower-like” morphologies or well-facetted diamond crystals with grain sizes ranging from 100 nm to 10 μm

  14. Blood-CNS Barrier Impairment in ALS Patients versus an Animal Model

    Directory of Open Access Journals (Sweden)

    Svitlana eGarbuzova-Davis

    2014-02-01

    Full Text Available Amyotrophic lateral sclerosis (ALS is a severe neurodegenerative disease with a compli-cated and poorly understood pathogenesis. Recently, alterations in the blood-Central Nervous System barrier (B-CNS-B have been recognized as a key factor possibly aggravating motor neuron damage. The majority of findings on ALS microvascular pathology have been deter-mined in mutant SOD1 rodent models, identifying barrier damage during disease develop-ment which might similarly occur in familial ALS patients carrying the SOD1 mutation. However, our knowledge of B-CNS-B competence in sporadic ALS (SALS has been limited. We recently showed structural and functional impairment in postmortem gray and white mat-ter microvessels of medulla and spinal cord tissue from SALS patients, suggesting pervasive barrier damage. Although numerous signs of barrier impairment (endothelial cell degenera-tion, capillary leakage, perivascular edema, downregulation of tight junction proteins, and microhemorrhages are indicated in both mutant SOD1 animal models of ALS and SALS pa-tients, other pathogenic barrier alterations have as yet only been identified in SALS patients. Pericyte degeneration, perivascular collagen IV expansion, and white matter capillary abnor-malities in SALS patients are significant barrier related pathologies yet to be noted in ALS SOD1 animal models. In the current review, these important differences in blood-CNS barrier damage between ALS patients and animal models, which may signify altered barrier transport mechanisms, are discussed. Understanding discrepancies in barrier condition between ALS patients and animal models may be crucial for developing effective therapies.

  15. Model assessment of protective barriers: Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Fayer, M.J.; Rockhold, M.L.; Holford, D.J.

    1992-02-01

    Radioactive waste exists at the US Department of Energy's (DOE's) Hanford Site in a variety of locations, including subsurface grout and tank farms, solid waste burial grounds, and contaminated soil sites. Some of these waste sites may need to be isolated from percolating water to minimize the potential for transport of the waste to the ground water, which eventually discharges to the Columbia River. Multilayer protective barriers have been proposed as a means of limiting the flow of water through the waste sites (DOE 1987). A multiyear research program (managed jointly by Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company for the DOE) is aimed at assessing the performance of these barriers. One aspect of this program involves the use of computer models to predict barrier performance. Three modeling studies have already been conducted and a test plan was produced. The simulation work reported here was conducted by PNL and extends the previous modeling work. The purpose of this report are to understand phenomena that have been observed in the field and to provide information that can be used to improve hydrologic modeling of the protective barrier. An improved modeling capability results in better estimates of barrier performance. Better estimates can be used to improve the design of barriers and the assessment of their long-term performance.

  16. Capillary Electrophoresis Analysis of Conventional Splicing Assays

    DEFF Research Database (Denmark)

    de Garibay, Gorka Ruiz; Acedo, Alberto; García-Casado, Zaida;

    2014-01-01

    Rare sequence variants in "high-risk" disease genes, often referred as unclassified variants (UVs), pose a serious challenge to genetic testing. However, UVs resulting in splicing alterations can be readily assessed by in vitro assays. Unfortunately, analytical and clinical interpretation...... of these assays is often challenging. Here, we explore this issue by conducting splicing assays in 31 BRCA2 genetic variants. All variants were assessed by RT-PCR followed by capillary electrophoresis and direct sequencing. If assays did not produce clear-cut outputs (Class-2 or Class-5 according to analytical...... International Agency for Research on Cancer guidelines), we performed qPCR and/or minigene assays. The latter were performed with a new splicing vector (pSAD) developed by authors of the present manuscript (patent #P201231427 CSIC). We have identified three clinically relevant Class-5 variants (c.682-2A>G, c...

  17. Current opinions of capillary leak syndrome

    Institute of Scientific and Technical Information of China (English)

    SU Jun; WANG Jin-quan; ZHANG Ying

    2012-01-01

    Capillary leak syndrome(CLS) in critically ill patients is common, and the clinical manifestations of CLS include systemic edema, hypoproteinemia, effective circulating blood volume reduction and blood concentrated.The common pathogenesy is sepsis, severe trauma, cardiopulmonary bypass and so on.CLS is divided into leakage period and recovery period usually. Clinical manifestation and treatment in different period are different in each pathophysiologic process.Although the methods of treatment are more, effective treatment measures are in shortage. More therapeutic measures are studied currently which include improvement of endothelial cell function, macromolecular colloidal solution application, continuous blood purification and so on. It is a guiding value to understand the pathological mechanism, clinical manifestations, diagnosis and treatment of the CLS.

  18. Capillary Pumped Heat Transfer (CHT) Experiment

    Science.gov (United States)

    Hallinan, Kevin P.; Allen, J. S.

    1998-01-01

    The operation of Capillary Pumped Loops (CPL's) in low gravity has generally been unable to match ground-based performance. The reason for this poorer performance has been elusive. In order to investigate the behavior of a CPL in low-gravity, an idealized, glass CPL experiment was constructed. This experiment, known as the Capillary-driven Heat Transfer (CHT) experiment, was flown on board the Space Shuttle Columbia in July 1997 during the Microgravity Science Laboratory mission. During the conduct of the CHT experiment an unexpected failure mode was observed. This failure mode was a result of liquid collecting and then eventually bridging the vapor return line. With the vapor return line blocked, the condensate was unable to return to the evaporator and dry-out subsequently followed. The mechanism for this collection and bridging has been associated with long wavelength instabilities of the liquid film forming in the vapor return line. Analysis has shown that vapor line blockage in present generation CPL devices is inevitable. Additionally, previous low-gravity CPL tests have reported the presence of relatively low frequency pressure oscillations during erratic system performance. Analysis reveals that these pressure oscillations are in part a result of long wavelength instabilities present in the evaporator pores, which likewise lead to liquid bridging and vapor entrapment in the porous media. Subsequent evaporation to the trapped vapor increases the vapor pressure. Eventually the vapor pressure causes ejection of the bridged liquid. Recoil stresses depress the meniscus, the vapor pressure rapidly increases, and the heated surface cools. The process then repeats with regularity.

  19. LANGUAGE BARRIERS: FEEDBACK FROM THE IT INDUSTRY

    Directory of Open Access Journals (Sweden)

    Sareen Kaur Bhar

    2013-02-01

    Full Text Available Meaningful interaction process between human beings necessitates effective communication especially in organisations that have rapid information exchange demands. It is perceived that most IT organisations that face communication and language barriers have lost businesses due to higher product defect rates, lack of focus on business objectives, stifled innovation and dissatisfied customers and poor customer services. This study looks at the language barriers faced by employees working in various fields related to Information Technology in Malaysia. A questionnaire was distributed to IT employees working in various international and national companies in Malaysia, and sixty two IT employees’ responses were accepted. The employees had to rate the effects of each language barrier on them in the context of the workplace. Based on these findings, barriers faced by IT employees in this field can now be better understood and steps can be taken by both the industry and education sectors to overcome these barriers. It will also aid these employees to be better communicators in facing the challenges in their industry and increase their competitiveness on a global scale. We conclude that future research should more explicitly consider the different configurations of language skills that are needed by IT staff.

  20. Surface stability test plan for protective barriers

    International Nuclear Information System (INIS)

    Natural-material protective barriers for long-term isolation of buried waste have been identified as integral components of a plan to isolate a number of Hanford defense waste sites. Standards currently being developed for internal and external barrier performance will mandate a barrier surface layer that is resistant to the eolian erosion processes of wind erosion (deflation) and windborne particle deposition (formation of sand dunes). Thus, experiments are needed to measure rates of eolian erosion processes impacting those surfaces under different surface and climatological conditions. Data from these studies will provide information for use in the evaluation of selected surface layers as a means of providing stable cover over waste sites throughout the design life span of protective barriers. The multi-year test plan described in this plan is directed at understanding processes of wind erosion and windborne particle deposition, providing measurements of erosion rates for models, and suggesting construction materials and methods for reducing the effect of long-term eolian erosion on the barrier. Specifically, this plan describes possible methods to measure rates of eolian erosion, including field and laboratory procedure. Advantages and disadvantages of laboratory (wind tunnel) tests are discussed, and continued wind tunnel tests are recommended for wind erosion studies. A comparison between field and wind tunnel erosive forces is discussed. Plans for testing surfaces are described. Guidance is also presented for studying the processes controlling sand dune and blowout formation. 24 refs., 7 figs., 3 tabs

  1. Guiding of charged particles through capillaries in insulating materials

    Science.gov (United States)

    Stolterfoht, Nikolaus; Yamazaki, Yasunori

    2016-04-01

    Studies of charged particle guiding through capillaries in insulating materials, performed during the last decade, are reviewed in a comprehensive manner. First, the principles of capillary guiding of slow highly charged ions are introduced describing the self-organized formation of charge patches. Basic quantities are defined, such as the guiding power characterizing a capillary. Challenges of the guiding experiments are pointed out. Then, experiments are described with emphasis on the guiding of highly charged ions in the keV energy range. Samples with an array of nanocapillaries as well as single macrocapillaries are treated. Emission profiles of transmitted ions are analyzed to establish scaling laws for the guiding angle, which quantifies the guiding power. Oscillations of the mean ion emission angle reveal the temporal dynamics of the charge patch formation. Next, experiments with ions of high (MeV) energies are focused on single tapered capillaries allowing for the production of a microbeam for various applications. Experiments concerning electrons are presented showing that apart from being elastically scattered these negative particles may enter into the capillary surface where they suffer energy losses. Finally, theoretical concepts of the capillary guiding are discussed. Simulations based on different charge transport methods clearly support the understanding of the guiding mechanisms. Altogether, capillary guiding involves several novel phenomena for which understanding have progressed far beyond their infancy.

  2. Capillary bundle model of hydraulic conductivity for frozen soil

    Science.gov (United States)

    Watanabe, Kunio; Flury, Markus

    2008-12-01

    We developed a capillary bundle model to describe water flow in frozen soil. We assume that the soil can be represented as a bundle of cylindrical capillaries. We consider that the freezing point in the capillaries is depressed according to the Gibbs-Thomson effect and that when stable ice forms in a capillary, the ice forms in the center of the capillaries, leaving a circular annulus open for liquid water flow. We use the model to demonstrate how the hydraulic conductivity changes as a function of temperature for both saturated and unsaturated soils, using a sand and two silt loam soils as examples. As temperature decreases, more and more ice forms, and the water flux consequently decreases. In frozen soil near 0°C, water predominantly flows through ice-free capillaries, so that the hydraulic conductivity of frozen soil is similar to that of an unfrozen soil with a water content equal to the unfrozen water content of the frozen soil. At low temperatures, however, ice forms in almost all capillaries, and the hydraulic conductivity of frozen soil is greater than that of unfrozen soil with the same water potential.

  3. Trapped liquid drop at the end of capillary.

    Science.gov (United States)

    Wang, Zhengjia; Yen, Hung-Yu; Chang, Cheng-Chung; Sheng, Yu-Jane; Tsao, Heng-Kwong

    2013-10-01

    The liquid drop captured at the capillary end, which is observed in capillary valve and pendant drop technique, is investigated theoretically and experimentally. Because of contact line pinning of the lower meniscus, the lower contact angle is able to rise from the intrinsic contact angle (θ*) so that the external force acting on the drop can be balanced by the capillary force. In the absence of contact angle hysteresis (CAH), the upper contact angle remains at θ*. However, in the presence of CAH, the upper contact angle can descend to provide more capillary force. The coupling between the lower and upper contact angles determines the equilibrium shape of the captured drop. In a capillary valve, the pinned contact line can move across the edge as the pressure difference exceeds the valving pressure, which depends on the geometrical characteristic and wetting property of the valve opening. When CAH is considered, the valving pressure is elevated because the capillary force is enhanced by the receding contact angle. For a pendant drop under gravity, the maximal capillary force is achieved as the lower contact angle reaches 180° in the absence of CAH. However, in the presence of CAH, four regimes can be identified by three critical drop volumes. The lower contact angle can exceed 180°, and therefore the drop takes on the shape of a light bulb, which does not exist in the absence of CAH. The comparisons between Surface Evolver simulations and experiments are quite well. PMID:24004041

  4. Method of installing subsurface barrier

    Science.gov (United States)

    Nickelson, Reva A.; Richardson, John G.; Kostelnik, Kevin M.; Sloan, Paul A.

    2007-10-09

    Systems, components, and methods relating to subterranean containment barriers. Laterally adjacent tubular casings having male interlock structures and multiple female interlock structures defining recesses for receiving a male interlock structure are used to create subterranean barriers for containing and treating buried waste and its effluents. The multiple female interlock structures enable the barriers to be varied around subsurface objects and to form barrier sidewalls. The barrier may be used for treating and monitoring a zone of interest.

  5. Application of capillary fluid management techniques to the design of a phase separating microgravity bioreactor

    Science.gov (United States)

    Finger, Barry W.; Neville, Gale E., Jr.; Sager, John C.

    1993-01-01

    Manned space missions require the development of compact, efficient, and reliable life support systems. A number of aqueous biological conversion processes are associated with bioregenerative life support systems. Vessels, or bioreactors, capable of supporting these processes in microgravity must be developed. An annular flow bioreactor has been conceived. It has the potential to incorporate containment, phase separation, gas exchange, and illumination into a single vessel. The bioreactor utilizes capillary fluid management techniques and is configured as a cylindrical tube in which a two-phase liquid-gas flow is maintained. Vanes placed around the inner perimeter enhance capillary forces and cause the liquid phase to attach and flow along the interior surface of the tube. No physical barrier is required to complete phase separation. It is shown analytically that liquid film thickness is limited only by vane geometry and that an annular flow bioreactor capable of managing 284 liters would occupy 0.7 cubic m, less than half the volume of a Spacelab experiment rack.

  6. Capillary electrophoresis for the assay of fixed-dose combination tablets of artesunate and amodiaquine

    Directory of Open Access Journals (Sweden)

    Amin N’Cho

    2012-05-01

    Full Text Available Abstract Background Quality control of drugs in formulations is still a major challenge in developing countries. For the quality control of artesunate and amodiaquine tablets in fixed-dose combination, only liquid chromatographic methods have been proposed in the literature. There are no capillary electrophoretic methods reported for the determination of these active substances, although this technique presents several advantages over liquid chromatography (long lifetime, low price of the capillary, low volumes of electrolyte consumption in addition to simplicity. In this paper, a reliable capillary electrophoresis method has been developed and validated for the quality control of these drugs in commercial fixed-dose combination tablets. Methods Artesunate and amodiaquine hydrochloride in bilayer tablets were determined by micellar electrokinetic capillary chromatography (MEKC. Analytes were extracted from tablets by sonication with a solvent mixture phosphate buffer pH 7.0-acetonitrile containing benzoic acid as internal standard. Separation was carried out on Beckman capillary electrophoresis system equipped with fused silica capillary, 30 cm long (20 cm to detector × 50 μm internal diameter, using a 25 mM borate buffer pH 9.2 containing 30 mM sodium dodecyl sulfate as background electrolyte, a 500 V cm−1 electric field and a detection wavelength of 214 nm. Results Artesunate, amodiaquine and benzoic acid were separated in 6 min. The method was found to be reliable with respect to specificity,linearity of the calibration line (r2 > 0.995, recovery from synthetic tablets (in the range 98–102%, repeatability (RSD 2–3%, n = 7 analytical procedures. Application to four batches of commercial formulations with different dosages gave content in good agreement with the declared content. Conclusion The MEKC method proposed is reliable for the determination of artesunate and amodiaquine hydrochloride in fixed

  7. Skin barrier in rosacea.

    Science.gov (United States)

    Addor, Flavia Alvim Sant'Anna

    2016-01-01

    Recent studies about the cutaneous barrier demonstrated consistent evidence that the stratum corneum is a metabolically active structure and also has adaptive functions, may play a regulatory role in the inflammatory response with activation of keratinocytes, angiogenesis and fibroplasia, whose intensity depends primarily on the intensity the stimulus. There are few studies investigating the abnormalities of the skin barrier in rosacea, but the existing data already show that there are changes resulting from inflammation, which can generate a vicious circle caused a prolongation of flare-ups and worsening of symptoms. This article aims to gather the most relevant literature data about the characteristics and effects of the state of the skin barrier in rosacea. PMID:26982780

  8. Thermal barrier coatings for gas turbine and diesel engines

    Science.gov (United States)

    Miller, Robert A.; Brindley, William J.; Bailey, M. Murray

    1989-01-01

    The present state of development of thin thermal barrier coatings for aircraft gas turbine engines and thick thermal barrier coatings for truck diesel engines is assessed. Although current thermal barrier coatings are flying in certain gas turbine engines, additional advances will be needed for future engines. Thick thermal barrier coatings for truck diesel engines have advanced to the point where they are being seriously considered for the next generation of engine. Since coatings for truck engines is a young field of inquiry, continued research and development efforts will be required to help bring this technology to commercialization.

  9. Blood-brain barrier properties in vitro depend on composition and assembly of endogenous extracellular matrices.

    Science.gov (United States)

    Zobel, Kathrin; Hansen, Uwe; Galla, Hans-Joachim

    2016-08-01

    Brain capillary endothelial cells, which constitute the blood-brain barrier (BBB), are enveloped by the extracellular matrix (ECM) produced by endothelial cells, pericytes and astrocytes. The contribution of matrix components secreted by the various cell types at the neurovascular unit, however, remains unclear with respect to their effect on endothelial barrier function. In this study, a new in vitro model was established by growing endothelial cells on an ECM produced by pericytes, astrocytes or a serial combination of both. The last-mentioned was found to be more in vivo-like. We investigated the role of the composition and morphology of ECM supra-structures in maintaining BBB function. The composition was analysed by protein analysis (enzyme-linked immunosorbent assay) and the ultrastructure of generated matrices was analysed by transmission electron microscopy including immunogold labelling. We could show by electric cell-substrate impedance sensing measurements that pericytes and combined matrices significantly improved the barrier tightness of porcine brain capillary endothelial cells (PBCEC). The increase of the resistance was verified by enhanced expression of tight junction proteins. Thus, for the first time, we have shown that barrier integrity is strictly controlled by the ECM, which is a product of all cells involved in the secretion of ECM components and their modification by corresponding cells. Moreover, we have demonstrated that complex matrices by the various cells of the BBB induce barrier marker enzymes in PBCEC, such as alkaline phosphatase. PMID:27053246

  10. Aquaporin 4 expression and ultrastructure of the blood-brain barrier following cerebral contusion injury

    Institute of Scientific and Technical Information of China (English)

    Xinjun Li; Yangyun Han; Hong Xu; Zhongshu Sun; Zengjun Zhou; Xiaodong Long; Yumin Yang; Linbo Zou

    2013-01-01

    This study aimed to investigate aquaporin 4 expression and the ultrastructure of the blood-brain barrier at 2–72 hours following cerebral contusion injury, and correlate these changes to the formation of brain edema. Results revealed that at 2 hours after cerebral contusion and laceration injury, aquaporin 4 expression significantly increased, brain water content and blood-brain barrier permeability increased, and the number of pinocytotic vesicles in cerebral microvascular endothelial cells increased. In addition, the mitochondrial accumulation was observed. As contusion and laceration injury became aggravated, aquaporin 4 expression continued to increase, brain water content and blood-brain barrier permeability gradually increased, brain capillary endothelial cells and astrocytes swelled, and capillary basement membrane injury gradually increased. The above changes were most apparent at 12 hours after injury, after which they gradually attenuated. Aquaporin 4 expression positively correlated with brain water content and the blood-brain barrier index. Our experimental findings indicate that increasing aquaporin 4 expression and blood-brain barrier permeability after cerebral contusion and laceration injury in humans is involved in the formation of brain edema.

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

    Science.gov (United States)

    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.

  12. Demonstration of a high repetition rate capillary discharge waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Gonsalves, A. J., E-mail: ajgonsalves@lbl.gov; Pieronek, C.; Daniels, J.; Bulanov, S. S.; Waldron, W. L.; Mittelberger, D. E.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Liu, F.; Antipov, S.; Butler, J. E. [Euclid TechLabs, Gaithersburg, Maryland 20879 (United States); Bobrova, N. A.; Sasorov, P. V. [Keldysh Institute of Applied Mathematics, Moscow (Russian Federation)

    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.

  13. Separation and quantification of cellulases and hemicellulases by capillary electrophoresis

    DEFF Research Database (Denmark)

    Jørgensen, Henning; Kutter, Jörg Peter; Olsson, Lisbeth

    2003-01-01

    . Current methods are limited in their ability to quantify all of these enzymes when all are present simultaneously in a mixture. Five different cellulases (two cellobiohydrolases and three endoglucanases) and one hemicellulase (endoxylanase) were separated using capillary electrophoresis (CE) in a fused...... silica capillary at pH values close to neutral. The improvement of the separation of these six proteins by the addition of alpha, omega-diaminoalkanes with chain lengths from three to seven carbon units was investigated. Dynamically coating the capillary with 1,3-diaminopropane resulted in separation of...

  14. Overcoming the Bradyon-Tachyon Barrier

    CERN Document Server

    Nanni, Luca

    2016-01-01

    In this study, the problem of overcoming the infinite energy barrier separating the bradyonic and tachyonic realms is investigated. Making use of the Majorana equation for particles with arbitrary spin and the Heisenberg uncertainty principle, it is proved that, under certain conditions of spatial confinement, quantum fluctuations allow particles with very small mass and velocity close to the speed of light to pass in the tachyonic realm, avoiding the problem of the infinite barrier. This theoretical approach allows an avoidance of the difficulties encountered in quantum field theory when it is extended to particles with imaginary rest mass.

  15. Interlayer exchange coupling across a ferroelectric barrier

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravlev, M Ye; Tsymbal, E Y [Department of Physics and Astronomy, Nebraska Center for Materials and Nanoscience, University of Nebraska, Lincoln, NE 68588 (United States); Vedyayev, A V, E-mail: myezhur@gmail.co, E-mail: tsymbal@unl.ed [Department of Physics, M V Lomonosov Moscow State University, Moscow 119899 (Russian Federation)

    2010-09-08

    A new magnetoelectric effect is predicted originating from the interlayer exchange coupling between two ferromagnetic layers separated by an ultrathin ferroelectric barrier. It is demonstrated that ferroelectric polarization switching driven by an external electric field leads to a sizable change in the interlayer exchange coupling. The effect occurs in asymmetric ferromagnet/ferroelectric/ferromagnet junctions due to a change in the electrostatic potential profile across the junction affecting the interlayer coupling. The predicted phenomenon indicates the possibility of switching the magnetic configuration by reversing the polarization of the ferroelectric barrier layer. (fast track communication)

  16. Interlayer exchange coupling across a ferroelectric barrier.

    Science.gov (United States)

    Zhuravlev, M Ye; Vedyayev, A V; Tsymbal, E Y

    2010-09-01

    A new magnetoelectric effect is predicted originating from the interlayer exchange coupling between two ferromagnetic layers separated by an ultrathin ferroelectric barrier. It is demonstrated that ferroelectric polarization switching driven by an external electric field leads to a sizable change in the interlayer exchange coupling. The effect occurs in asymmetric ferromagnet/ferroelectric/ferromagnet junctions due to a change in the electrostatic potential profile across the junction affecting the interlayer coupling. The predicted phenomenon indicates the possibility of switching the magnetic configuration by reversing the polarization of the ferroelectric barrier layer. PMID:21403276

  17. Cross-talk effect in electrostatic based capillary array nozzles

    International Nuclear Information System (INIS)

    Electrohydrodynamic printing is a promising technique for printed electronics application. Most researchers working in this field are using a single nozzle configuration. However, for large area printing a multi-nozzle setup will be required for time and cost effective process. In this paper the influence of electric field and flow-rate on jetting angle on multi-nozzle array has been investigated experimentally. A three nozzle setup has been used in a linear array by using glass capillary as a nozzle with independent voltage applied on each nozzle and independent ink supply. The experiments are performed by changing the nozzle to nozzle gap and the effect on the jetting angle has been investigated. It has been observed that by increasing the applied voltage the jetting angle also increases at fixed flow-rate. In case of increasing the flow-rate, the jetting angle first increases with increase in flow-rate, but as the flow-rate increases at certain level the jetting angle decreases; moreover, at a high flow-rate the cone-jet length starts increasing. Numerical simulation has been performed to have a better understanding of the electric-field with respect to jetting angles. The influence of one nozzle on another nozzle is also investigated by operating the nozzle independently by using different operating cases. The cross-talk effect is also minimized by reducing the nozzle diameter. At 250 μm nozzle diameter the cross-talk effect was negligible for 5 mm nozzle-to-nozzle gap. This study will help in better understanding of the interaction between different nozzles in multi-nozzle cases and better design of the multi-nozzle system by minimizing the effects of adjacent nozzles for multi-nozzle electrohydrodynamic printing system

  18. Properties of native ultrathin aluminium oxide tunnel barriers

    CERN Document Server

    Gloos, K; Pekola, J P

    2003-01-01

    We have investigated planar metal-insulator-metal tunnel junctions with aluminium oxide as the dielectricum. These oxide barriers were grown on an aluminium electrode in pure oxygen at room temperature till saturation. By applying the Simmons model we derived discrete widths of the tunnelling barrier, separated by DELTA s approx 0.38 nm. This corresponds to the addition of single layers of oxygen atoms. The minimum thickness of s sub 0 approx 0.54 nm is then due to a double layer of oxygen. We found a strong and systematic dependence of the barrier height on the barrier thickness. Breakdown fields up to 5 GV m sup - sup 1 were reached. They decreased strongly with increasing barrier thickness. Electrical breakdown could be described by a metal-insulator like transition of the dielectric barrier due to the large density of tunnelling electrons.

  19. Sapphire capillaries for laser-driven wakefield acceleration in plasma. Fs-laser micromachining and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schwinkendorf, Jan-Patrick

    2012-08-15

    Plasma wakefields are a promising approach for the acceleration of electrons with ultrahigh (10 to 100 GV/m) electric fields. Nowadays, high-intensity laser pulses are routinely utilized to excite these large-amplitude plasma waves. However, several detrimental effects such as laser diffraction, electron-wake dephasing and laser depletion may terminate the acceleration process. Two of these phenomena can be mitigated or avoided by the application of capillary waveguides, e.g. fabricated out of sapphire for longevity. Capillaries may compensate for laser diffraction like a fiber and allow for the creation of tapered gas-density profiles working against the dephasing between the accelerating wave and the particles. Additionally, they offer the possibility of controlled particle injection. This thesis is reporting on the set up of a laser for fs-micromachining of capillaries of almost arbitrary shapes and a test stand for density-profile characterization. These devices will permit the creation of tailored gas-density profiles for controlled electron injection and acceleration inside plasma.

  20. Simulation of intense laser pulse propagation in capillary discharge plasma channels

    International Nuclear Information System (INIS)

    Many applications of ultra intense laser pulses require propagation in plasmas over distances of many Rayleigh lengths. Hollow plasma channels such as those produced by a capillary discharge have successfully guided pulses with small spot size (rs approximately 30 microm) over distances as long as 6 cm. Recent experiments have extended the capillary discharge technique to laser intensities of 1017 W/cm3. These experiments use a double capillary design that allows more control over plasma parameters. Simulations of laser propagation in these channels show that the laser pulse radius undergoes oscillations about the expected matched radius rM at the expected frequency. The pulse may be distorted by several effects, including laser-generated ionization and plasma motion in the intense laser fields. In addition, finite pulse length corrections to the wave equation cause initially the oscillations in the laser beam size to damp in the front of the beam and grow in the back. Eventually, the oscillations are damped by phase mixing effects. Experiments to date have been at relatively high densities (approximately 1019 cm-3). For standard laser wakefield accelerator applications, the on-axis channel density is likely to be substantially lower. As expected, simulations in this lower density regime show lower accelerating gradients, larger laser spot sizes, and higher wakefield phase velocities. The dephasing limit on single stage final electron beam energy is thus also much higher. Possible methods for producing lower density plasma channels will also be discussed

  1. Changes in labial capillary density on ascent to and descent from high altitude [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Edward Gilbert-Kawai

    2016-08-01

    Full Text Available Present knowledge of how the microcirculation is altered by prolonged exposure to hypoxia at high altitude is incomplete and modification of existing analytical techniques may improve our knowledge considerably. We set out to use a novel simplified method of measuring in vivo capillary density during an expedition to high altitude using a CytoCam incident dark field imaging video-microscope. The simplified method of data capture involved recording one-second images of the mucosal surface of the inner lip to reveal data about microvasculature density in ten individuals. This was done on ascent to, and descent from, high altitude. Analysis was conducted offline by two independent investigators blinded to the participant identity, testing conditions and the imaging site.  Additionally we monitored haemoglobin concentration and haematocrit data to see if we could support or refute mechanisms of altered density relating to vessel recruitment. Repeated sets of paired values were compared using Kruskall Wallis Analysis of Variance tests, whilst comparisons of values between sites was by related samples Wilcoxon Signed Rank Test. Correlation between different variables was performed using Spearman’s rank correlation coefficient, and concordance between analysing investigators using intra-class correlation coefficient. There was a significant increase in capillary density from London on ascent to high altitude; median capillaries per field of view area increased from 22.8 to 25.3 (p=0.021. There was a further increase in vessel density during the six weeks spent at altitude (25.3 to 32.5, p=0.017. Moreover, vessel density remained high on descent to Kathmandu (31.0 capillaries per field of view area, despite a significant decrease in haemoglobin concentration and haematocrit. Using a simplified technique, we have demonstrated an increase in capillary density on early and sustained exposure to hypobaric hypoxia at thigh altitude, and that this remains

  2. Barriers in Quantum Gravity

    OpenAIRE

    Ambjorn, Jan

    1994-01-01

    I discuss recent progress in our understanding of two barriers in quantum gravity: $c > 1$ in the case of 2d quantum gravity and $D > 2$ in the case of Euclidean Einstein-Hilbert gravity formulated in space-time dimensions $D >2$.

  3. Breaking Down Barriers.

    Science.gov (United States)

    Watkins, Beverly T.

    1994-01-01

    Faculty at 11 higher education institutions in California, New Mexico, Texas, and northern Mexico have been experimenting with computer conferencing on the BESTNET (Bilingual English-Spanish Telecommunications Network). The growing system is credited with creating an international student-faculty community that crosses cultural barriers for…

  4. In situ observation and analysis of ultrasonic capillary effect in molten aluminium.

    Science.gov (United States)

    Tzanakis, I; Xu, W W; Eskin, D G; Lee, P D; Kotsovinos, N

    2015-11-01

    An in situ synchrotron radiographic study of a molten Al-10 wt% Cu alloy under the influence of an external ultrasonic field was carried out using the Diamond-Manchester Branchline pink X-ray imaging at the Diamond Light Source in UK. A bespoke test rig was used, consisting of an acoustic transducer with a titanium sonotrode coupled with a PID-controlled resistance furnace. An ultrasonic frequency of 30 kHz, with a peak to peak amplitude at 140 microns, was used, producing a pressure output of 16.9 MPa at the radiation surface of the 1-mm diameter sonotrode. This allowed quantification of not only the cavitation bubble formation and collapse, but there was also evidence of the previously hypothesised ultrasonic capillary effect (UCE), providing the first direct observations of this phenomenon in a molten metallic alloy. This was achieved by quantifying the re-filling of a pre-existing groove in the shape of a tube (which acted as a micro-capillary channel) formed by the oxide envelope of the liquid sample. Analytical solutions of the flow suggest that the filling process, which took place in very small timescales, was related to micro-jetting from the collapsing cavitation bubbles. In addition, a secondary mechanism of liquid penetration through the groove, which is related with the density distribution of the oxides inside the groove, and practically to the filtration of aluminium melt from oxides, was revealed. The observation of the almost instantaneous re-filling of a micro-capillary channel with the metallic melt supports the hypothesised sono-capillary effect in technologically important liquids other than water, like metallic alloys with substantially higher surface tension and density. PMID:26186822

  5. High Performance Wafer-Based Capillary Electrochromatography Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop wafer-based capillary electrochromatography for lab-on-a-chip (LOC) applications. These microfluidic devices will be...

  6. Study of a heat rejection system using capillary pumping

    Science.gov (United States)

    Neal, L. G.; Wanous, D. J.; Clausen, O. W.

    1971-01-01

    Results of an analytical study investigating the application of capillary pumping to the heat rejection loop of an advanced Rankine cycle power conversion system are presented. The feasibility of the concept of capillary pumping as an alternate to electromagnetic pumping is analytically demonstrated. Capillary pumping is shown to provide a potential for weight and electrical power saving and reliability through the use of redundant systems. A screen wick pump design with arterial feed lines was analytically developed. Advantages of this design are high thermodynamic and hydrodynamic efficiency, which provide a lightweight easily packaged system. Operational problems were identified which must be solved for successful application of capillary pumping. The most important are the development of start up and shutdown procedures, and development of a means of keeping noncondensibles from the system and of earth-bound testing procedures.

  7. Improved Refrigerant Characteristics Flow Predictions in Adiabatic Capillary Tube

    Directory of Open Access Journals (Sweden)

    Shodiya Sulaimon

    2012-07-01

    Full Text Available This study presents improved refrigerant characteristics flow predictions using homogenous flow model in adiabatic capillary tube, used in small vapor compression refrigeration system. The model is based on fundamental equations of mass, momentum and energy. In order to improve the flow predictions, the inception of vaporization in the capillary tube is determined by evaluating initial vapor quality using enthalpy equation of refrigerant at saturation point and the inlet entrance effect of the capillary tube is also accounted for. Comparing this model with experimental data from open literature showed a reasonable agreement. Further comparison of this new model with earlier model of Bansal showed that the present model could be use to improve the performance predictions of refrigerant flow in adiabatic capillary tube.

  8. Giant congenital capillary hemangioma of pericranium--case report.

    Science.gov (United States)

    Tokuda, Y; Uozumi, T; Sakoda, K; Yamada, K; Yamanaka, M; Nomura, S; Hamasaki, T

    1990-12-01

    The authors report a newborn male infant with a giant congenital capillary hemangioma of the pericranium. An elastic mass, measuring 6.5 x 6.9 x 3.9 cm, was located in the parieto-occipital region. Neurological examination revealed no abnormality. Angiographically, the tumor was fed symmetrically by the bilateral superficial temporal, occipital, and middle meningeal arteries. At surgery, the encapsulated tumor appeared to have arisen from the periosteum and was removed completely. Histological diagnosis was capillary hemangioma. Capillary hemangioma is a common benign tumor in infancy and usually present as a strawberry mark or port-wine stain. However, when the tumors seat relatively deeply as in the present case, they produce little or no discoloration in the overlying skin. Angiography is then useful to differentiate capillary hemangioma from other lesions and to choose an appropriate treatment. PMID:1714050

  9. Optical emission spectroscopy observations of fast pulsed capillary discharge plasmas

    Science.gov (United States)

    Avaria, G.; Ruiz, M.; Guzmán, F.; Favre, M.; Wyndham, E. S.; Chuaqui, H.; Bhuyan, H.

    2014-05-01

    We present time resolved optical emission spectroscopic (OES) observations of a low energy, pulsed capillary discharage (PCD). The optical emission from the capillary plasma and plasma jets emitted from the capillary volume was recorded with with a SpectraPro 275 spectrograph, fitted with a MCP gated OMA system, with 15 ns time resolution. The discharge was operated with different gases, including argon, nitrogen, hydrogen and methane, in a repetitive pulsed discharge mode at 10-50 Hz, with, 10-12 kV pulses applied at the cathode side. The time evolution of the electron density was measured using Stark broadening of the Hβ line. Several features of the capillary plasma dynamics, such as ionization growth, wall effects and plasma jet evolution, are inferred from the time evolution of the optical emission.

  10. Targeted Functionalization of Nanoparticle Thin Films via Capillary Condensation

    KAUST Repository

    Gemici, Zekeriyya

    2009-03-11

    Capillary condensation, an often undesired natural phenomenon in nanoporous materials, was used advantageously as a universal functionalization strategy in nanoparticle thin films assembled layer-by-layer. Judicious choice of nanoparticle (and therefore pore) size allowed targeted capillary condensation of chemical vapors of both hydrophilic and hydrophobic molecules across film thickness. Heterostructured thin films with modulated refractive index profiles produced in this manner exhibited broadband antireflection properties with an average reflectance over the visible region of the spectrum of only 0.4%. Capillary condensation was also used to modify surface chemistry and surface energy. Photosensitive capillary-condensates were UV-cross-linked in situ. Undesired adventitious condensation of humidity could be avoided by condensation of hydrophobic materials such as poly(dimethyl siloxane). © 2009 American Chemical Society.

  11. A capillary based chemiluminscent multi-target immunoassay.

    Science.gov (United States)

    Cao, Yuan-Cheng

    2015-05-01

    Renewed interest in capillary format immunoassays has lead to increasingly costly and complex approaches to preparation and readout. This study describes a simple multi-target method based on a capillary platform using horseradish peroxidase (HRP) labelled IgG to visualize an antibody antigen complex. When goat-anti-human IgG was employed as the probe and human IgG as target, the system allowed detection of target to less than 1 ng/mL using a standard detection approach. The capillaries were read visually or with a commercial grade CCD camera. Multi-target detection was demonstrated using a model system of rat-anti-mouse, goat-anti-human and mouse-anti-rat IgG. These probes were encoded to different locations in the capillary, providing a simple inexpensive approach to achieve multi-target assays. PMID:25731812

  12. PHYSIOLOGY AND PATHOPHYSIOLOGY OF THE BLOOD BRAIN BARRIER: P-glycoprotein and occludin trafficking as therapeutic targets to optimize CNS drug delivery

    OpenAIRE

    McCaffrey, Gwen; Davis, Thomas P.

    2012-01-01

    The blood-brain barrier (BBB) is a physical and metabolic barrier that separates the CNS from the peripheral circulation. CNS drug delivery across the BBB is challenging, primarily due to the physical restriction of paracellular diffusion between the endothelial cells that comprise the microvessels of the BBB and the activity of efflux transporters that quickly expel back into the capillary lumen a wide variety of xenobiotics. Therapeutic manipulation of protein trafficking is emerging as a n...

  13. 3D numerical simulation of the flow field with push-pull hoods containing barriers between them%罩间存在障碍物的吹吸罩流场三维数值模拟

    Institute of Scientific and Technical Information of China (English)

    胡鸿; 易灿南; 廖可兵

    2013-01-01

    为了使吹吸罩达到对污染物的最佳控制,以某企业电镀生产线上行车行进过程中由于镀件表面黏附高浓度槽液而造成室内环境污染为实物模型,建立吹吸罩口间存在障碍物的三维数学模型,利用Fluent计算动力学软件对不同吹风口风速和吸风口风速下的排风罩流场进行数值模拟,经比较确定最佳联合速度,并将模拟结果与经典吹吸速度分布图及试验条件下所测得的污染气体质量分数进行对比分析.结果表明,所建立数学模型是合理的,所确定的最佳效果时的相关参数与经典理论基本一致,可用于工程实际.%This paper attempts to proposo a 3D numerical simulation model of the flow field with push-pull hoods containing barriers between them in hoping to solve the problem of the dispersion of contaminants.As is known,the dispersion of contaminants in different sections of an apparatus can be controlled effectively via a pull-push hood powered by a jet flow.Actually,such device has already been widely used in places where contaminants are serious but can not be eliminated.The said push-pullhoods are usually armed with the following features:minute air volume,perfect pollution control,powerful anti-jam behavior,free from the impact of the process operations.Although no barriers were considered in the former design between the push hood and pull hood in the regular production process according to the processing demands,we still feel it necessary to stress the demand for them,for it is necessary to choose the best velocity of push hood and pull hood to control the containments.Based on the above starting point,we have chosen the computational fluid dynamics (CFD) model to solve the problem.First of all,we have taken the contaminants accumulated in the painted work-pieces with very harmful content adhered in them as a physical model,while assuming that geometrical models are set by the GAMBIT code.Along with it,let the appropriate

  14. Capillary Array Waveguide Amplified Fluorescence Detector for mHealth.

    Science.gov (United States)

    Balsam, Joshua; Bruck, Hugh Alan; Rasooly, Avraham

    2013-09-01

    Mobile Health (mHealth) analytical technologies are potentially useful for carrying out modern medical diagnostics in resource-poor settings. Effective mHealth devices for underserved populations need to be simple, low cost, and portable. Although cell phone cameras have been used for biodetection, their sensitivity is a limiting factor because currently it is too low to be effective for many mHealth applications, which depend on detection of weak fluorescent signals. To improve the sensitivity of portable phones, a capillary tube array was developed to amplify fluorescence signals using their waveguide properties. An array configured with 36 capillary tubes was demonstrated to have a ~100X increase in sensitivity, lowering the limit of detection (LOD) of mobile phones from 1000 nM to 10 nM for fluorescein. To confirm that the amplification was due to waveguide behavior, we coated the external surfaces of the capillaries with silver. The silver coating interfered with the waveguide behavior and diminished the fluorescence signal, thereby proving that the waveguide behavior was the main mechanism for enhancing optical sensitivity. The optical configuration described here is novel in several ways. First, the use of capillaries waveguide properties to improve detection of weak florescence signal is new. Second we describe here a three dimensional illumination system, while conventional angular laser waveguide illumination is spot (or line), which is functionally one-dimensional illumination, can illuminate only a single capillary or a single column (when a line generator is used) of capillaries and thus inherently limits the multiplexing capability of detection. The planar illumination demonstrated in this work enables illumination of a two dimensional capillary array (e.g. x columns and y rows of capillaries). In addition, the waveguide light propagation via the capillary wall provides a third dimension for illumination along the axis of the capillaries. Such an

  15. Barriers to SCM implementing

    Directory of Open Access Journals (Sweden)

    M.E. Rosli

    2008-12-01

    Full Text Available Purpose: This paper explores the barriers faced by Malaysian manufacturing companies in successfullyimplementing the Supply Chain Management (SCM. The study has highlighted some pertinent factorsperforming the barriers that are most frequently reported by the studied companies. Sixteen companies, fromservice and manufacturing companies were studied over a period of two years to assess their SCM practicesthrough survey and interview processes.Design/methodology/approach: This part discusses the research design and methodological issues upon whichthe research is based. The explanation includes two types of research methods, short survey and follow-upinterviews that were identified as being suitable to achieve the aims of this study, which is to identify the currentproblem of SCM practices within the Malaysian SMEs. Research design is a framework or plan for researchused as a guide in collecting and analysing data.Findings: The results showed that the barriers are depending on the types or group of companies business; suchas either it is an SME or a big company. The barriers inhibiting the practice of SCM can be summarized inthe following factors: partnership with suppliers, limited expertise, management commitment, understanding ofSCM, supported technologies and customer satisfaction. The findings are also compared with the results of asimilar study on SCM in other country.Practical implications: Some suggestions are also offered, which is believed to be a good strategy to the companiesto manage the SCM that will lead to sustainable competitive advantage and hence improve their market share.Originality/value: There are interesting barriers between the companies in Malaysia and other country in therespect of SCM implementation. These findings can be used by both Malaysian and other companies to worktogether or review the SCM strategies that will lead to sustainable competitive advantage and hence improvetheir business performance.

  16. Stability of capillary gels for automated sequencing of DNA.

    Science.gov (United States)

    Swerdlow, H; Dew-Jager, K E; Brady, K; Grey, R; Dovichi, N J; Gesteland, R

    1992-08-01

    Recent interest in capillary gel electrophoresis has been fueled by the Human Genome Project and other large-scale sequencing projects. Advances in gel polymerization techniques and detector design have enabled sequencing of DNA directly in capillaries. Efforts to exploit this technology have been hampered by problems with the reproducibility and stability of gels. Gel instability manifests itself during electrophoresis as a decrease in the current passing through the capillary under a constant voltage. Upon subsequent microscopic examination, bubbles are often visible at or near the injection (cathodic) end of the capillary gel. Gels have been prepared with the polyacrylamide matrix covalently attached to the silica walls of the capillary. These gels, although more stable, still suffer from problems with bubbles. The use of actual DNA sequencing samples also adversely affects gel stability. We examined the mechanisms underlying these disruptive processes by employing polyacrylamide gel-filled capillaries in which the gel was not attached to the capillary wall. Three sources of gel instability were identified. Bubbles occurring in the absence of sample introduction were attributed to electroosmotic force; replacing the denaturant urea with formamide was shown to reduce the frequency of these bubbles. The slow, steady decline in current through capillary sequencing gels interferes with the ability to detect other gel problems. This phenomenon was shown to be a result of ionic depletion at the gel-liquid interface. The decline was ameliorated by adding denaturant and acrylamide monomers to the buffer reservoirs. Sample-induced problems were shown to be due to the presence of template DNA; elimination of the template allowed sample loading to occur without complications.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Pulmonary Surfactant Surface Tension Influences Alveolar Capillary Shape and Oxygenation

    OpenAIRE

    Ikegami, Machiko; Weaver, Timothy E.; Grant, Shawn N.; Whitsett, Jeffrey A.

    2009-01-01

    Alveolar capillaries are located in close proximity to the alveolar epithelium and beneath the surfactant film. We hypothesized that the shape of alveolar capillaries and accompanying oxygenation are influenced by surfactant surface tension in the alveolus. To prove our hypothesis, surfactant surface tension was regulated by conditional expression of surfactant protein (SP)-B in Sftpb−/− mice, thereby inhibiting surface tension–lowering properties of surfactant in vivo within 24 hours after d...

  18. Optimized photonic crystal fibers supporting efficient capillary electrophoresis

    Science.gov (United States)

    Calcerrada, M.; García-Ruiz, C.; Roy, P.; Gonzalez-Herraez, M.

    2013-05-01

    In this paper we present preliminary results on the use of Photonic Crystal Fibers (PCFs) in a conventional capillary electrophoresis system to separate and detect fluorescent species. PCFs show interesting advantages over conventional capillaries for this application, including larger surface-to-volume ratio and potential for higher resolution with comparable sensitivity. Our results illustrate some of these advantages, and we point out the need for stringent tolerances in the fabrication of specific PCFs for this application.

  19. Spatiotemporal phase-matching in capillary high-harmonic generation

    OpenAIRE

    Rogers, Edward T.F.; Stebbings, Sarah L; de Paula, Ana M.; Froud, Christopher A.; Praeger, Matthew; Mills, Benjamin; Grant-Jacob, James; Brocklesby, William S; Frey, Jeremy G

    2012-01-01

    We present a simple phase-matching model that takes into account the full spatiotemporal nature of capillary high-harmonic generation. Spectra predicted from the model are compared to experimental results for a number of gases and are shown to reproduce the spectral envelope of experimentally generated harmonics. The model demonstrates that an ionization-induced phase mismatch is limiting the energy of the generated harmonics in current capillary high-harmonic generation experiments. The succ...

  20. Modified monolithic silica capillary for preconcentration of catecholamines

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Preconcentration of catecholamines by the modified monolithic silica in the capillary was investigated in this study. In order to achieve a microchip-based method for determining catecholamines in the saliva,the monolithic silica was fabricated in the capillary and the monolithic silica was chemically modified by on-column reaction with phenylboronate. Different modified methods were compared. The concentration conditions were optimized. This study indicates the applicability of the modified monolithic sili...

  1. Fabrication and Visualization of Capillary Bridges in Slit Pore Geometry

    OpenAIRE

    Broesch, David J.; Frechette, Joelle

    2014-01-01

    A procedure for creating and imaging capillary bridges in slit-pore geometry is presented. High aspect ratio hydrophobic pillars are fabricated and functionalized to render their top surfaces hydrophilic. The combination of a physical feature (the pillar) with a chemical boundary (the hydrophilic film on the top of the pillar) provides both a physical and chemical heterogeneity that pins the triple contact line, a necessary feature to create stable long but narrow capillary bridges. The subst...

  2. Capillary Flow in an Interior Corner

    Science.gov (United States)

    Weislogel, Mark Milton

    1996-01-01

    The design of fluids management processes in the low-gravity environment of space requires an accurate model and description of capillarity-controlled flow in containers of irregular geometry. Here we consider the capillary rise of a fluid along an interior corner of a container following a rapid reduction in gravity. The analytical portion of the work presents an asymptotic formulation in the limit of a slender fluid column, slight surface curvature along the corner, small inertia, and low gravity. New similarity solutions are found and a list of closed form expressions is provided for flow rate and column length. In particular, it is found that the flow is proportional to t(exp 1/2) for a constant height boundary condition, t(exp 2/5) for a spreading drop, and t(exp 3/5) for constant flow. In the experimental portion of the work, measurements from a 2.2s drop tower are reported. An extensive data set, collected over a previously unexplored range of flow parameters, includes estimates of repeatability and accuracy, the role of inertia and column slenderness, and the effects of corner angle, container geometry, and fluid properties. Comprehensive comparisons are made which illustrate the applicability of the analytic results to low-g fluid systems design.

  3. Idiopathic systemic capillary leak syndrome in children.

    Science.gov (United States)

    Hsu, Peter; Xie, Zhihui; Frith, Katie; Wong, Melanie; Kakakios, Alyson; Stone, Kelly D; Druey, Kirk M

    2015-03-01

    Adult subjects with systemic capillary leak syndrome (SCLS) present with acute and recurrent episodes of vascular leak manifesting as severe hypotension, hypoalbuminemia, hemoconcentration, and generalized edema. We studied clinical disease characteristics, serum cytokine profiles, and treatment modalities in a cohort of children with documented SCLS. Six children with SCLS were recruited from the United States, Australia, Canada, and Italy. Serum cytokines from SCLS subjects and a group of 10 healthy children were analyzed. Children with SCLS (aged 5-11 years old) presented with at least 1 acute, severe episode of hypotension, hypoalbuminemia, and hemoconcentration in the absence of underlying causes for these abnormalities. In contrast to what is observed in adult SCLS, identifiable infectious triggers precipitated most episodes in these children, and none of them had a monoclonal gammopathy. We found elevated levels of chemokine (C-C motif) ligand 2 (CCL2), interleukin-8, and tumor necrosis factor α in baseline SCLS sera compared with the control group. All patients are alive and well on prophylactic therapy, with 4 patients receiving intravenous or subcutaneous immunoglobulins at regular intervals. The clinical manifestations of pediatric and adult SCLS are similar, with the notable exceptions of frequent association with infections and the lack of monoclonal gammopathy. Prophylactic medication, including high dose immunoglobulins or theophylline plus verapamil, appears to be safe and efficacious therapy for SCLS in children. PMID:25713284

  4. Fabricating PFPE Membranes for Capillary Electrophoresis

    Science.gov (United States)

    Lee, Michael C.; Willis, Peter A.; Greer, Frank; Rolland, Jason

    2009-01-01

    A process has been developed for fabricating perfluoropolyether (PFPE) membranes that contain microscopic holes of precise sizes at precise locations. The membranes are to be incorporated into laboratory-on-a-chip microfluidic devices to be used in performing capillary electrophoresis. The present process is a modified version of part of the process, described in the immediately preceding article, that includes a step in which a liquid PFPE layer is cured into solid (membrane) form by use of ultraviolet light. In the present process, one exploits the fact that by masking some locations to prevent exposure to ultraviolet light, one can prevent curing of the PFPE in those locations. The uncured PFPE can be washed away from those locations in the subsequent release and cleaning steps. Thus, holes are formed in the membrane in those locations. The most straightforward way to implement the modification is to use, during the ultraviolet-curing step, an ultraviolet photomask similar to the photomasks used in fabricating microelectronic devices. In lieu of such a photomask, one could use a mask made of any patternable ultraviolet-absorbing material (for example, an ink or a photoresist).

  5. THE CAPILLARY PATTERN IN HUMAN MASSETER MUSCLE DURING AGEING

    Directory of Open Access Journals (Sweden)

    Erika Cvetko

    2013-10-01

    Full Text Available The effect of ageing on the capillary network in skeletal muscles has produced conflicting results in both, human and animals studies. Some of the inconsistencies are due to non-comparable and biased methods that were applied on thin transversal sections, especially in muscles with complicated morphological structures, such as in human masseter muscle. We present a new immunohistochemical method for staining capillaries and muscle fibres in 100 µm thick sections as well as novel approach to 3D visualization of capillaries and muscle fibres. Applying confocal microscopy and virtual 3D stereological grids, or tracing capillaries in virtual reality, length of capillaries within a muscle volume or length of capillaries adjacent to muscle fibre per fibre length, fibre surface or fibre volume were evaluated in masseter muscle of young and old subjects by an unbiased approach. Our findings show that anatomic capillarity is well maintained in masseter muscle in old subjects; however, vascular remodelling occurs with age, which could be a response to changed muscle function and age-related muscle fibre type transformations.

  6. Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

    Directory of Open Access Journals (Sweden)

    Árpád Gyéresi

    2013-02-01

    Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

  7. Temperature control of ion guiding through tapered capillaries

    Energy Technology Data Exchange (ETDEWEB)

    Gruber, Elisabeth, E-mail: egruber@iap.tuwien.ac.at [Institute of Applied Physics, TU Wien – Vienna University of Technology, 1040 Vienna (Austria); Stolterfoht, Nikolaus [Helmholtz-Zentrum Berlin für Materialien und Energie, D-14109 Berlin (Germany); Allinger, Peter; Wampl, Stefan [Institute of Applied Physics, TU Wien – Vienna University of Technology, 1040 Vienna (Austria); Wang, Yuyu [Institute of Applied Physics, TU Wien – Vienna University of Technology, 1040 Vienna (Austria); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu (China); Simon, Marius J. [Labor für Ionenstrahlphysik, ETH Zürich, 8093 Zürich (Switzerland); Aumayr, Friedrich, E-mail: aumayr@iap.tuwien.ac.at [Institute of Applied Physics, TU Wien – Vienna University of Technology, 1040 Vienna (Austria)

    2014-12-01

    We investigate the guiding of Ar{sup 7+} ions (kinetic energy of 4.5 keV) through a single macroscopic tapered glass capillary of conical shape as a function of capillary tilt angle with respect to the incident ion beam direction. At room temperature a minimum in the transmitted ion intensity appears around the forward direction, which was previously observed and interpreted by a blocking of the transmission by repulsive Coulomb forces due to a uniformly charged ring shaped region in the centre part of the capillary. By heating the tapered capillary to temperatures around 100 °C and thus drastically increasing the electrical conductivity of the capillary material we no longer observe a minimum in the transmission curve but the transmission curve now has its maximum in forward direction. Since the maximum transmission at high temperature in forward direction is still smaller than the minimum in transmitted intensity at room temperature, we conclude that even at room temperature and in forward direction the focusing effect due to guiding is dominant and only partially weakened by blocking. Our experimental results are well reproduced in simulations using a theoretical model originally developed for straight nano-capillaries.

  8. A Fractal Model for Capillary Pressure of Porous Media

    Directory of Open Access Journals (Sweden)

    Boqi Xiao

    2013-06-01

    Full Text Available Capillary pressure is a basic parameter in the study of the behavior of porous media containing two or more immiscible fluid phases. In this study, the capillary pressure of porous media is predicted based on based on fractal property of pore in porous media. The formula of calculating the capillary pressure of porous media is given. The capillary pressure of porous media is expressed as a function of porosity, fractal dimension of pore and saturation. Based on the parametric effect analysis, we conclude that the capillary pressure of porous media is negatively correlated with the porosity and saturation. Besides, it is shown that the capillary pressure of unsaturated porous media decreases with the increase of saturation. No additional empirical constant is introduced. This model contains less empirical constants than the conventional correlations. The model predictions are compared with the existing experimental data and good agreement between the model predictions and experimental data is found. The validity of the present fractal model is thus verified.

  9. Fabrication and visualization of capillary bridges in slit pore geometry.

    Science.gov (United States)

    Broesch, David J; Frechette, Joelle

    2014-01-01

    A procedure for creating and imaging capillary bridges in slit-pore geometry is presented. High aspect ratio hydrophobic pillars are fabricated and functionalized to render their top surfaces hydrophilic. The combination of a physical feature (the pillar) with a chemical boundary (the hydrophilic film on the top of the pillar) provides both a physical and chemical heterogeneity that pins the triple contact line, a necessary feature to create stable long but narrow capillary bridges. The substrates with the pillars are attached to glass slides and secured into custom holders. The holders are then mounted onto four axis microstages and positioned such that the pillars are parallel and facing each other. The capillary bridges are formed by introducing a fluid in the gap between the two substrates once the separation between the facing pillars has been reduced to a few hundred micrometers. The custom microstage is then employed to vary the height of the capillary bridge. A CCD camera is positioned to image either the length or the width of the capillary bridge to characterize the morphology of the fluid interface. Pillars with widths down to 250 µm and lengths up to 70 mm were fabricated with this method, leading to capillary bridges with aspect ratios (length/width) of over 100(1). PMID:24457446

  10. Geophysical characterization of subsurface barriers

    Energy Technology Data Exchange (ETDEWEB)

    Borns, D.J.

    1995-08-01

    An option for controlling contaminant migration from plumes and buried waste sites is to construct a subsurface barrier of a low-permeability material. The successful application of subsurface barriers requires processes to verify the emplacement and effectiveness of barrier and to monitor the performance of a barrier after emplacement. Non destructive and remote sensing techniques, such as geophysical methods, are possible technologies to address these needs. The changes in mechanical, hydrologic and chemical properties associated with the emplacement of an engineered barrier will affect geophysical properties such a seismic velocity, electrical conductivity, and dielectric constant. Also, the barrier, once emplaced and interacting with the in situ geologic system, may affect the paths along which electrical current flows in the subsurface. These changes in properties and processes facilitate the detection and monitoring of the barrier. The approaches to characterizing and monitoring engineered barriers can be divided between (1) methods that directly image the barrier using the contrasts in physical properties between the barrier and the host soil or rock and (2) methods that reflect flow processes around or through the barrier. For example, seismic methods that delineate the changes in density and stiffness associated with the barrier represents a direct imaging method. Electrical self potential methods and flow probes based on heat flow methods represent techniques that can delineate the flow path or flow processes around and through a barrier.

  11. Geophysical characterization of subsurface barriers

    International Nuclear Information System (INIS)

    An option for controlling contaminant migration from plumes and buried waste sites is to construct a subsurface barrier of a low-permeability material. The successful application of subsurface barriers requires processes to verify the emplacement and effectiveness of barrier and to monitor the performance of a barrier after emplacement. Non destructive and remote sensing techniques, such as geophysical methods, are possible technologies to address these needs. The changes in mechanical, hydrologic and chemical properties associated with the emplacement of an engineered barrier will affect geophysical properties such a seismic velocity, electrical conductivity, and dielectric constant. Also, the barrier, once emplaced and interacting with the in situ geologic system, may affect the paths along which electrical current flows in the subsurface. These changes in properties and processes facilitate the detection and monitoring of the barrier. The approaches to characterizing and monitoring engineered barriers can be divided between (1) methods that directly image the barrier using the contrasts in physical properties between the barrier and the host soil or rock and (2) methods that reflect flow processes around or through the barrier. For example, seismic methods that delineate the changes in density and stiffness associated with the barrier represents a direct imaging method. Electrical self potential methods and flow probes based on heat flow methods represent techniques that can delineate the flow path or flow processes around and through a barrier

  12. Wall modified photonic crystal fibre capillaries as porous layer open tubular columns for in-capillary micro-extraction and capillary chromatography.

    Science.gov (United States)

    Kazarian, Artaches A; Sanz Rodriguez, Estrella; Deverell, Jeremy A; McCord, James; Muddiman, David C; Paull, Brett

    2016-01-28

    Wall modified photonic crystal fibre capillary columns for in-capillary micro-extraction and liquid chromatographic separations is presented. Columns contained 126 internal parallel 4 μm channels, each containing a wall bonded porous monolithic type polystyrene-divinylbenzene layer in open tubular column format (PLOT). Modification longitudinal homogeneity was monitored using scanning contactless conductivity detection and scanning electron microscopy. The multichannel open tubular capillary column showed channel diameter and polymer layer consistency of 4.2 ± 0.1 μm and 0.26 ± 0.02 μm respectively, and modification of 100% of the parallel channels with the monolithic polymer. The modified multi-channel capillaries were applied to the in-capillary micro-extraction of water samples. 500 μL of water samples containing single μg L(-1) levels of polyaromatic hydrocarbons were extracted at a flow rate of 10 μL min(-1), and eluted in 50 μL of acetonitrile for analysis using HPLC with fluorescence detection. HPLC LODs were 0.08, 0.02 and 0.05 μg L(-1) for acenaphthene, anthracene and pyrene, respectively, with extraction recoveries of between 77 and 103%. The modified capillaries were also investigated briefly for direct application to liquid chromatographic separations, with the retention and elution of a standard protein (cytochrome c) under isocratic conditions demonstrated, proving chromatographic potential of the new column format, with run-to-run retention time reproducibility of below 1%.

  13. Tracer kinetic modelling in MRI: estimating perfusion and capillary permeability

    International Nuclear Information System (INIS)

    The tracer-kinetic models developed in the early 1990s for dynamic contrast-enhanced MRI (DCE-MRI) have since become a standard in numerous applications. At the same time, the development of MRI hardware has led to increases in image quality and temporal resolution that reveal the limitations of the early models. This in turn has stimulated an interest in the development and application of a second generation of modelling approaches. They are designed to overcome these limitations and produce additional and more accurate information on tissue status. In particular, models of the second generation enable separate estimates of perfusion and capillary permeability rather than a single parameter Ktrans that represents a combination of the two. A variety of such models has been proposed in the literature, and development in the field has been constrained by a lack of transparency regarding terminology, notations and physiological assumptions. In this review, we provide an overview of these models in a manner that is both physically intuitive and mathematically rigourous. All are derived from common first principles, using concepts and notations from general tracer-kinetic theory. Explicit links to their historical origins are included to allow for a transfer of experience obtained in other fields (PET, SPECT, CT). A classification is presented that reveals the links between all models, and with the models of the first generation. Detailed formulae for all solutions are provided to facilitate implementation. Our aim is to encourage the application of these tools to DCE-MRI by offering researchers a clearer understanding of their assumptions and requirements. (topical review)

  14. Tracer kinetic modelling in MRI: estimating perfusion and capillary permeability

    Science.gov (United States)

    Sourbron, S. P.; Buckley, D. L.

    2012-01-01

    The tracer-kinetic models developed in the early 1990s for dynamic contrast-enhanced MRI (DCE-MRI) have since become a standard in numerous applications. At the same time, the development of MRI hardware has led to increases in image quality and temporal resolution that reveal the limitations of the early models. This in turn has stimulated an interest in the development and application of a second generation of modelling approaches. They are designed to overcome these limitations and produce additional and more accurate information on tissue status. In particular, models of the second generation enable separate estimates of perfusion and capillary permeability rather than a single parameter Ktrans that represents a combination of the two. A variety of such models has been proposed in the literature, and development in the field has been constrained by a lack of transparency regarding terminology, notations and physiological assumptions. In this review, we provide an overview of these models in a manner that is both physically intuitive and mathematically rigourous. All are derived from common first principles, using concepts and notations from general tracer-kinetic theory. Explicit links to their historical origins are included to allow for a transfer of experience obtained in other fields (PET, SPECT, CT). A classification is presented that reveals the links between all models, and with the models of the first generation. Detailed formulae for all solutions are provided to facilitate implementation. Our aim is to encourage the application of these tools to DCE-MRI by offering researchers a clearer understanding of their assumptions and requirements.

  15. The alveolar-capillary membrane diffusing capacity and the pulmonary capillary blood volume in heart transplant candidates

    OpenAIRE

    Al-Rawas, O; Carter, R.; Stevenson, R; Naik, S; Wheatley, D

    2000-01-01

    OBJECTIVES—To determine the mechanism of impairment of pulmonary transfer factor for carbon monoxide (TLCO) in heart transplant candidates, as this is the most common lung function abnormality.
SETTING—Regional cardiopulmonary transplant centre.
METHODS—TLCO and its components (the diffusing capacity of the alveolar-capillary membrane (DM) and the pulmonary capillary blood volume (VC)) were measured using the Roughton and Forster method and the single breath technique in 38 patients with seve...

  16. Minutes of Fish Barrier Workshop

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Minutes of Fish Barrier Workshop held 27 May 2009 at DOC Waikato Area Office. Lists attendees and highlights topics to be covered in Fish Barrier Workshop.

  17. Study on capillary electrophoresis enrichment and separation system based on field magnified injection-electric counter balance purge-trap and its application in iron ore detection%基于场放大进样-电动反平衡扫集的毛细管电泳富集分离系统的研究及其在铁矿石检测中的应用

    Institute of Scientific and Technical Information of China (English)

    张效伟

    2013-01-01

    Combining with field magnified injection technology,the determination of six heavy metal elements (manganese,chromium,lead,copper,nickel and cobalt) in iron ore by on-line dual-enrichment capillary electrophoresis enrichment and separation system based on field magnified injection-electric counter balance purge-trap was established using EDTA as trap carrier.The metal ions were firstly accumulated on the interface between water plug and high-conductivity buffer solution via field magnified injection,and then trapped by oncoming negative charged EDTA.The sample region was further compressed,realizing the dual amplification of signal.By controlling the electro-osmotic flow,the metal-EDTA chelate was under quasi-static condition.Thus,the large volume injection and significant amplification of detection signal were realized.After dual-enrichment at 15 kV for 50 min,the sensitivity increased by 1.2 × 104-8.5 × 104 times than that of conventional capillary electrophoresis.The detection limits of six heavy metal ions in iron ore were 0.06-0.32 μg/L.The proposed method was applied to the determination of manganese,chromium,lead,copper,nickel and cobalt in iron ore.The relative error between determination results of proposed method and those of ICP-MS was between 5.3 %-11.5 %.%利用EDTA作为捕获载体,结合场放大进样技术,建立了一种基于场放大进样-电动反平衡扫集在线双重富集的毛细管电泳富集分离新体系并用于铁矿石中锰、铬、铅、铜、镍和钴6种重金属元素的检测.金属离子首先通过场放大进样堆积在水塞与高电导缓冲溶液的界面上,然后被迎面而来的带负电荷的EDTA捕获,样品区带被进一步压缩,实现信号的双重放大.通过控制电渗流使金属-EDTA螯合物处于准静止状态,实现大体积进样及检测信号的高度放大.通过15 kV电动进样50 min双重富集后,灵敏度比常规毛细管电泳提高了1.2×104~8.5×104倍,铁矿石中6种重

  18. Restraint stress-induced morphological changes at the blood-brain barrier in adult rats

    Directory of Open Access Journals (Sweden)

    Petra eSántha

    2016-01-01

    Full Text Available Stress is well known to contribute to the development of both neurological and psychiatric diseases. While the role of the blood-brain barrier is increasingly recognised in the development of neurodegenerative disorders, such as Alzheimer’s disease, dysfunction of the blood-brain barrier has been linked to stress-related psychiatric diseases only recently. In the present study the effects of restraint stress with different duration (1, 3 and 21 days were investigated on the morphology of the blood-brain barrier in male adult Wistar rats. Frontal cortex and hippocampus sections were immunostained for markers of brain endothelial cells (claudin-5, occludin and glucose transporter-1 and astroglia (GFAP. Staining pattern and intensity were visualized by confocal microscopy and evaluated by several types of image analysis. The ultrastructure of brain capillaries was investigated by electron microscopy. Morphological changes and intensity alterations in brain endothelial tight junction proteins claudin-5 and occludin were induced by stress. Following restraint stress significant increases in the fluorescence intensity of glucose transporter-1 were detected in brain endothelial cells in the frontal cortex and hippocampus. Significant reductions in GFAP fluorescence intensity were observed in the frontal cortex in all stress groups. As observed by electron microscopy, one-day acute stress induced morphological changes indicating damage in capillary endothelial cells in both brain regions. After 21 days of stress thicker and irregular capillary basal membranes in the hippocampus and edema in astrocytes in both regions were seen. These findings indicate that stress exerts time-dependent changes in the staining pattern of tight junction proteins occludin, claudin-5 and glucose transporter-1 at the level of brain capillaries and in the ultrastructure of brain endothelial cells and astroglial endfeet, which may contribute to neurodegenerative processes

  19. Sonic Crystal Noise Barriers

    OpenAIRE

    Chong, Yung

    2012-01-01

    An alternative road traffic noise barrier using an array of periodically arranged vertical cylinders known as a Sonic Crystal (SC) is investigated. As a result of multiple (Bragg) scattering, SCs exhibit a selective sound attenuation in frequency bands called band gaps or stop bands related to the spacing and size of the cylinders. Theoretical studies using Plane Wave Expansion (PWE), Multiple Scattering Theory (MST) and Finite Element Method (FEM) have enabled study of the performance of SC ...

  20. PHARMACOVIGILANCE: BARRIERS AND CHALLENGES

    OpenAIRE

    Varma, S. K.; RAPELLIWAR A; S. Sutradhar; THAWARE P; Misra, A. K.

    2013-01-01

    Pharmacovigilance is a new discipline which deals with adverse drug or any drug related problems. Pharmacovigilance programme was not bed of roses but its path is laid with challenges and barriers. It is facing obstacles from deficiency from professional health personal to web-based sale of drugs, counterfeit drug to self-medication, etc. It is an integral part of the health sector and identification and reporting of adverse drug effects will have a positive impact on the public health. Impro...

  1. Thermal barrier coating materials

    Directory of Open Access Journals (Sweden)

    David R. Clarke

    2005-06-01

    Full Text Available Improved thermal barrier coatings (TBCs will enable future gas turbines to operate at higher gas temperatures. Considerable effort is being invested, therefore, in identifying new materials with even better performance than the current industry standard, yttria-stabilized zirconia (YSZ. We review recent progress and suggest that an integrated strategy of experiment, intuitive arguments based on crystallography, and simulation may lead most rapidly to the development of new TBC materials.

  2. Determination of seven aromatic amines in hair dyes by capillary electrophoresis coupled with field-amplified sample stacking%毛细管电泳-场强放大样品堆积法检测染发剂中的7种苯胺类物质

    Institute of Scientific and Technical Information of China (English)

    卢玉超; 王海燕; 宋萍萍; 刘书慧

    2011-01-01

    建立了毛细管电泳-场强放大样品堆积测定染发剂中4,4′-二氨基二苯甲烷、苯胺、邻甲氧基苯胺、对氨基苯甲醚、3,4-二甲基苯胺、间氨基苯酚、1-萘胺7种苯胺类物质的分析方法.在优化的缓冲溶液体系(0.15 mol/L NaH2PO4,0.015 mol/L 三乙醇胺,pH 2.3)下7种分析物在6.5 min内实现基线分离.考察了样品中添加的磷酸浓度和乙腈浓度、水柱长度、电动进样时间与电压对场强放大富集效率及重现性的影响.最佳的富集条件为:水柱注入3.45 kPa(0.5 psi)×6 s,样品中添加40%(v/v)乙腈和0.6×10-3 mol/L 磷酸,进样电压与进样时间为10 kV×10 s.线性范围为3~1000 μg/L(R2>0.996),检出限为0.26~2.75 μg/L,将已有方法的检测灵敏度提高了1~3个数量级.在2种市售黑色染发剂中均检测到间氨基苯酚,含量分别为7.32 mg/g和1.34 mg/g.平均加标回收率为74% ~108%.该方法灵敏度高、快速、重现性好、成本低,可供多种样品基质中痕量苯胺类污染物及其他阳离子物质的测定借鉴使用.%A method for the determination of 4,4'-methylenedianiline, aniline, o-anisidine, 3, 4-dimethylaniline, p-anisidine, 3-aminophenol, 1-naphthylamine in hair dyes was established by capillary electrophoresis coupled with field-amplified sample stacking. The optimum running buffer was an aqueous solution containing 0. 15 mol/L NaH2PO4 and 0.015 mol/L trolamine ( pH 2. 3 ), and the baseline separation was achieved within 6. 5 min. The effects of phosphoric acid and acetonitrile concentration in the sample matrix, the length of the preinjection water plug, and the sample injection voltage and time on the stacking efficiency were investigated. The optimum stacking conditions for the real samples included a water plug of 3. 45 kPa (0. 5 psi) × 6 s, the addition of 40%( v/v ) acetonitrile and 0. 6 × 10 -3 mol/L phosphoric acid to the sample solution and a sample injection of 10 kV × 10 s. The seven

  3. Capillary absorption spectrometer and process for isotopic analysis of small samples

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, M. Lizabeth; Kelly, James F.; Sams, Robert L.; Moran, James J.; Newburn, Matthew K.; Blake, Thomas A.

    2016-03-29

    A capillary absorption spectrometer and process are described that provide highly sensitive and accurate stable absorption measurements of analytes in a sample gas that may include isotopologues of carbon and oxygen obtained from gas and biological samples. It further provides isotopic images of microbial communities that allow tracking of nutrients at the single cell level. It further targets naturally occurring variations in carbon and oxygen isotopes that avoids need for expensive isotopically labeled mixtures which allows study of samples taken from the field without modification. The method also permits sampling in vivo permitting real-time ambient studies of microbial communities.

  4. Barrier infrared detector

    Science.gov (United States)

    Ting, David Z. (Inventor); Khoshakhlagh, Arezou (Inventor); Soibel, Alexander (Inventor); Hill, Cory J. (Inventor); Gunapala, Sarath D. (Inventor)

    2012-01-01

    A superlattice-based infrared absorber and the matching electron-blocking and hole-blocking unipolar barriers, absorbers and barriers with graded band gaps, high-performance infrared detectors, and methods of manufacturing such devices are provided herein. The infrared absorber material is made from a superlattice (periodic structure) where each period consists of two or more layers of InAs, InSb, InSbAs, or InGaAs. The layer widths and alloy compositions are chosen to yield the desired energy band gap, absorption strength, and strain balance for the particular application. Furthermore, the periodicity of the superlattice can be "chirped" (varied) to create a material with a graded or varying energy band gap. The superlattice based barrier infrared detectors described and demonstrated herein have spectral ranges covering the entire 3-5 micron atmospheric transmission window, excellent dark current characteristics operating at least 150K, high yield, and have the potential for high-operability, high-uniformity focal plane arrays.

  5. Similarity Criteria of Surface Dielectric Barrier Discharge Plasma Induced Flow-field and Its Application%表面介质阻挡放电等离子体诱导流场相似准则及应用

    Institute of Scientific and Technical Information of China (English)

    车学科; 聂万胜; 田希晖; 陈庆亚; 姜家文

    2016-01-01

    According to the aerodynamics momentum and energy equations, the similarity criteria of body force and releasing heat induced by surface dielectric barrier discharge plasma flow control were studied on the basis of the similarity theory.The body force similarity criterion is essentially Reynolds number similarity which has three forms according to the experimental conditions.When the air is quiescent, the Reynolds number can be obtained using the maximal velocity and jet half height of induced jet.For free stream, the force unit length similarity based on the force unit length, free stream velocity, and kinetic viscosity coefficient can be used, or the velocity-modified Reynolds number similarity can be applied that the Reynolds number in quiescent air is modified by the maximal velocity of induced jet and free stream velocity.The releasing heat similarity criterion is dimensionless perturbation pressure similarity.The velocity-modified Reynolds number similarity is used to simulate the S1223 airfoil plasma flow control at altitude 20 km.It is found that when the angle of attack is positive and the Reynolds number is low, the lift coefficient will increase by about 10%~55% even if the angle of attack is quite high.The flow fields on up and down surfaces of airfoil are modified by plasma.But when the free stream Reynolds number is high, plasma acts weakly.%利用相似变换法,由空气动力学动量方程和能量方程推导得出了表面介质阻挡放电等离子体流动控制实验研究时的体积力和放热相似准则.等离子体体积力相似本质上为一种雷诺数相似,根据实验条件的不同其有不同的表现形式:对于静止空气,体积力相似为基于诱导射流最大速度和射流半高宽的射流雷诺数相似;有来流时,可以采用基于激励器单位长度作用力、来流速度和动力粘性系数的单位长度作用力相似,也可以用诱导射流最大速度与来流速度的比值对静止空气诱导

  6. On the factors which contribute to thinning of the villous membrane in human placentae at high altitude. II. An increase in the degree of peripheralization of fetal capillaries.

    Science.gov (United States)

    Jackson, M R; Mayhew, T M; Haas, J D

    1988-01-01

    The contribution made by fetal capillary peripheralization to the thinning of the villous membrane seen in human placentae from high-altitude pregnancies is examined by stereological methods. Variables characterizing the shape of the villous core and the spatial relationships between trophoblast and capillaries are quantified. They shed light on the relative importance of dynamic versus mechanistic processes of villous membrane attenuation. Highland villi differ from lowland villi in several ways. On average, they possess a thinner barrier due to closer approximation of capillaries to overlying trophoblast; in consequence, the villous core is more irregular in outline and its surface (that of the inner aspect of the trophoblast) exceeds in area that of the outer aspect of the trophoblast. These results suggest that the dynamic process (protoplasmic streaming within syncytiotrophoblast) cannot alone explain thinning of the villous membrane. A mechanistic process (capillary peripheralization and obtrusion into the trophoblastic epithelium) is sufficient to account for the differences observed, although the possibility that both processes operate concurrently cannot be discounted. This report completes a study into factors contributing to villous membrane thinning at high altitude. PMID:3362794

  7. Long term performance of the Waterloo denitrification barrier

    International Nuclear Information System (INIS)

    Beginning in 1991 a series of laboratory tests and small scale field trials were initiated to test the performance of an innovative permeable reactive barrier for treatment of nitrate from septic systems. The barrier promotes denitrification by providing an energy source in the form of solid organic carbon mixed into the porous media material. Advantages of the system for nitrate treatment are that the reaction is passive and in situ and it is possible to incorporate sufficient carbon mass in conveniently sized barriers to potentially provide treatment for long periods (decades) without the necessity for maintenance. However, longevity can only be demonstrated by careful long term monitoring of field installations. This paper documents four years of operating history at three small scale field trials; two where the denitrification barrier is installed as a horizontal layer positioned in the unsaturated zone below conventional septic system infiltration beds and one where the barrier is installed as a vertical wall intercepting a septic system plume at a downgradient location. The barriers have successfully attenuated 50-100% of NO-3-N levels of up to 170 mg/L and treatment has remained consistent over the four year period in each case, thus considerable longevity is indicated. Other field trials have demonstrated this technology to be equally effective in treating nitrogen contamination from other sources such as landfill leachate and farm field runoff

  8. Long term performance of the Waterloo denitrification barrier

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, W.D.; Cherry, J.A. [Univ. of Waterloo, Ontario (Canada)

    1997-12-31

    Beginning in 1991 a series of laboratory tests and small scale field trials were initiated to test the performance of an innovative permeable reactive barrier for treatment of nitrate from septic systems. The barrier promotes denitrification by providing an energy source in the form of solid organic carbon mixed into the porous media material. Advantages of the system for nitrate treatment are that the reaction is passive and in situ and it is possible to incorporate sufficient carbon mass in conveniently sized barriers to potentially provide treatment for long periods (decades) without the necessity for maintenance. However, longevity can only be demonstrated by careful long term monitoring of field installations. This paper documents four years of operating history at three small scale field trials; two where the denitrification barrier is installed as a horizontal layer positioned in the unsaturated zone below conventional septic system infiltration beds and one where the barrier is installed as a vertical wall intercepting a septic system plume at a downgradient location. The barriers have successfully attenuated 50-100% of NO{sup -}{sub 3}-N levels of up to 170 mg/L and treatment has remained consistent over the four year period in each case, thus considerable longevity is indicated. Other field trials have demonstrated this technology to be equally effective in treating nitrogen contamination from other sources such as landfill leachate and farm field runoff.

  9. Interplay between flow and diffusion in capillary alginate hydrogels.

    Science.gov (United States)

    Schuster, Erich; Sott, Kristin; Ström, Anna; Altskär, Annika; Smisdom, Nick; Gebäck, Tobias; Lorén, Niklas; Hermansson, Anne-Marie

    2016-05-01

    Alginate gels with naturally occurring macroscopic capillaries have been used as a model system to study the interplay between laminar flow and diffusion of nanometer-sized solutes in real time. Calcium alginate gels that contain homogeneously distributed parallel-aligned capillary structures were formed by external addition of crosslinking ions to an alginate sol. The effects of different flow rates (0, 1, 10, 50 and 100 μl min(-1)) and three different probes (fluorescein, 10 kDa and 500 kDa fluorescein isothiocyanate-dextran) on the diffusion rates of the solutes across the capillary wall and in the bulk gel in between the capillaries were investigated using confocal laser scanning microscopy. The flow in the capillaries was produced using a syringe pump that was connected to the capillaries via a tube. Transmission electron microscopy revealed an open aggregated structure close to the capillary wall, followed by an aligned network layer and the isotropic network of the bulk gel. The most pronounced effect was observed for the 1 nm-diameter fluorescein probe, for which an increase in flow rate increased the mobility of the probe in the gel. Fluorescence recovery after photobleaching confirmed increased mobility close to the channel, with increasing flow rate. Mobility maps derived using raster image correlation spectroscopy showed that the layer with the lowest mobility corresponded to the anisotropic layer of ordered network chains. The combination of microscopy techniques used in the present study elucidates the flow and diffusion behaviors visually, qualitatively and quantitatively, and represents a promising tool for future studies of mass transport in non-equilibrium systems.

  10. Simulating the evolution of an ethanol and gasoline source zone within the capillary fringe.

    Science.gov (United States)

    Yu, Soonyoung; Freitas, Juliana G; Unger, Andre J A; Barker, James F; Chatzis, John

    2009-02-27

    Blending of ethanol into gasoline as a fuel oxygenate has created the scenario where inadvertent releases of E95 into soil previously contaminated by gasoline may remobilize these pre-existing NAPLs and lead to higher dissolved hydrocarbon (BTEX) concentrations in groundwater. We contribute to the development of a risk-based corrective action framework addressing this issue by conducting two laboratory experiments involving the release of ethanol into a gasoline source zone established in the capillary fringe. We then develop and apply the numerical model CompFlow Bio to replicate three specific experimental observations: (1) depression of the capillary fringe by the addition of the gasoline fuel mixture due to a reduction in the surface tension between the gas and liquid phases, (2) further depression of the capillary fringe by the addition of ethanol, and (3) remobilization of the gasoline fuel mixture LNAPL source zone due to the cosolvent behaviour of ethanol in the presence of an aqueous phase, as well as a reduction in the interfacial tension between the aqueous/non-aqueous phases due to ethanol. While the simulated collapse of the capillary fringe was not as extensive as that which was observed, the simulated and observed remobilized non-aqueous phase distributions were in agreement following ethanol injection. Specifically, injection of ethanol caused the non-aqueous phase to advect downwards toward the water table as the capillary fringe continued to collapse, finally collecting on top of the water table in a significantly reduced area exhibiting higher saturations than observed prior to ethanol injection. Surprisingly, the simulated ethanol and gasoline aqueous phase plumes were uniform despite the redistribution of the source zone. Dissolution of gasoline into the aqueous phase was dramatically increased due to the cosolvency effect of ethanol on the non-aqueous phase source zone. We advocate further experimental studies focusing on eliminating data gaps

  11. Experimental investigation on diabatic flow of R-134a through spiral capillary tube

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Mohd. Kaleem [Department of Mechanical Engineering, Thapar University, Patiala 147 004 (India); Kumar, Ravi; Sahoo, Pradeep K. [Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247 667, Uttarakhand (India)

    2009-03-15

    The present experimental investigation has been carried out to investigate the effects of various geometric parameters on the mass flow rate of R-134a through diabatic spiral capillary tube. In diabatic flow, the capillary tube is bonded with the compressor suction-line to form a counter-flow exchanger. The lateral type of diabatic capillary tube has been investigated in the present experimental study. The major geometric parameters investigated are capillary tube diameter, capillary tube length and coil pitch. In addition, effect of inlet subcooling on the mass flow rate through diabatic spiral capillary tube is also done. A comparison of the performance of diabatic spiral capillary tube has been made with adiabatic spiral capillary tube. Generalized empirical correlation for diabatic spiral capillary tube has also been proposed. It has been found that the predictions of the proposed correlation lie in the error band of {+-}7%. (author)

  12. Advances in Capillary Chromatography%毛细管色谱的进展

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The difference of diffusion coefficient in gas and liquid phase is a key role. The study for obtaining a high performance capillary liquid chromatography is discussed. Capillary electrochromatography is recently interesting for its instinct ability to realize a high performance chromatography. Capillary electrochromatography with and without pressurized flow is reviewed briefly. Instrumentation for capillary electrochromatography with pressurized flow is discussed. The port of splitting, and gradient elution of both solution and potential are described. The new findings of both the variation of column resistance and capacity factor according to the value of applied electric voltage are also discussed.

  13. Protection of the blood-brain barrier by pentosan against amyloid-β-induced toxicity.

    Science.gov (United States)

    Deli, Mária A; Veszelka, Szilvia; Csiszár, Boglárka; Tóth, Andrea; Kittel, Agnes; Csete, Mária; Sipos, Aron; Szalai, Anikó; Fülöp, Lívia; Penke, Botond; Abrahám, Csongor S; Niwa, Masami

    2010-01-01

    Endothelial cells of brain capillaries forming the blood-brain barrier play an important role in the pathogenesis and therapy of Alzheimer's disease. Amyloid-β (Aβ) peptides are key pathological elements in the development of the disease. A blood-brain barrier model, based on primary rat brain endothelial cells was used in which the barrier properties were induced by glial cells. The effects of amyloid peptides have been tested on cell viability and barrier functions. Aβ showed toxic effects on primary rat brain endothelial cells measured by MTT dye conversion and the lactate dehydrogenase release. Morphologically cytoplasmic vacuolization, disruption of the structure of cytoplasmic organelles and tight junctions could be observed in brain endothelial cells. Treatment with Aβ1-42 decreased the electrical resistance, and increased the permeability of brain endothelial cell monolayers for both fluorescein and albumin. Serum amyloid P component which stabilizes Aβ fibrils in cortical amyloid plaques and cerebrovascular amyloid deposits significantly potentiated the barrier-weakening effect of Aβ1-42. Sulfated polysaccharide pentosan could decrease the toxic effects of Aβ peptides in brain endothelial cells. It could also significantly protect the barrier integrity of monolayers from damaging actions of peptides. Pentosan modified the size, and significantly decreased the number of amyloid aggregates demonstrated by atomic force microscopy. The present data further support the toxic effects of amyloid peptides on brain endothelial cells, and can contribute to the development of molecules protecting the blood-brain barrier in Alzheimer's disease.

  14. Barrier-protective effects of activated protein C in human alveolar epithelial cells.

    Directory of Open Access Journals (Sweden)

    Ferranda Puig

    Full Text Available Acute lung injury (ALI is a clinical manifestation of respiratory failure, caused by lung inflammation and the disruption of the alveolar-capillary barrier. Preservation of the physical integrity of the alveolar epithelial monolayer is of critical importance to prevent alveolar edema. Barrier integrity depends largely on the balance between physical forces on cell-cell and cell-matrix contacts, and this balance might be affected by alterations in the coagulation cascade in patients with ALI. We aimed to study the effects of activated protein C (APC on mechanical tension and barrier integrity in human alveolar epithelial cells (A549 exposed to thrombin. Cells were pretreated for 3 h with APC (50 µg/ml or vehicle (control. Subsequently, thrombin (50 nM or medium was added to the cell culture. APC significantly reduced thrombin-induced cell monolayer permeability, cell stiffening, and cell contraction, measured by electrical impedance, optical magnetic twisting cytometry, and traction microscopy, respectively, suggesting a barrier-protective response. The dynamics of the barrier integrity was also assessed by western blotting and immunofluorescence analysis of the tight junction ZO-1. Thrombin resulted in more elongated ZO-1 aggregates at cell-cell interface areas and induced an increase in ZO-1 membrane protein content. APC attenuated the length of these ZO-1 aggregates and reduced the ZO-1 membrane protein levels induced by thrombin. In conclusion, pretreatment with APC reduced the disruption of barrier integrity induced by thrombin, thus contributing to alveolar epithelial barrier protection.

  15. Surface barrier research at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Gee, G.W.; Ward, A.L.; Fayer, M.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-12-31

    At the DOE Hanford Site, a field-scale prototype surface barrier was constructed in 1994 over an existing waste site as a part of a CERCLA treatability test. The above-grade barrier consists of a fine-soil layer overlying coarse layers of sands, gravels, basalt rock (riprap), and a low permeability asphalt layer. Two sideslope configurations, clean-fill gravel on a 10:1 slope and basalt riprap on a 2:1 slope, were built and are being tested. Design considerations included: constructability; drainage and water balance monitoring, wind and water erosion control and monitoring; surface revegetation and biotic intrusion; subsidence and sideslope stability, and durability of the asphalt layer. The barrier is currently in the final year of a three-year test designed to answer specific questions related to stability and long-term performance. One half of the barrier is irrigated such that the total water applied, including precipitation, is 480 mm/yr (three times the long-term annual average). Each year for the past two years, an extreme precipitation event (71 mm in 8 hr) representing a 1,000-yr return storm was applied in late March, when soil water storage was at a maximum. While the protective sideslopes have drained significant amounts of water, the soil cover (2-m of silt-loam soil overlying coarse sand and rock) has never drained. During the past year there was no measurable surface runoff or wind erosion. This is attributed to extensive revegetation of the surface. In addition, the barrier elevation has shown a small increase of 2 to 3 cm that is attributed to a combination of root proliferation and freeze/thaw activity. Testing will continue through September 1997. Performance data from the prototype barrier will be used by DOE in site-closure decisions at Hanford.

  16. Barriers for recess physical activity

    DEFF Research Database (Denmark)

    Pawlowski, Charlotte Skau; Tjørnhøj-Thomsen, Tine; Schipperijn, Jasper;

    2014-01-01

    differences in children's perceptions of barriers to recess physical activity. Based on the socio-ecological model four types of environmental barriers were distinguished: natural, social, physical and organizational environment. METHODS: Data were collected through 17 focus groups (at 17 different schools......BACKGROUND: Many children, in particular girls, do not reach the recommended amount of daily physical activity. School recess provides an opportunity for both boys and girls to be physically active, but barriers to recess physical activity are not well understood. This study explores gender...... and girls identified the same barriers, there were both inter- and intra-gender differences in the perception of these barriers. Weather was a barrier for all children, apart from the most active boys. Conflicts were perceived as a barrier particularly by those boys who played ballgames. Girls said...

  17. Modeling Fluid’s Dynamics with Master Equations in Ultrametric Spaces Representing the Treelike Structure of Capillary Networks

    OpenAIRE

    Andrei Khrennikov; Klaudia Oleschko; María de Jesús Correa López

    2016-01-01

    We present a new conceptual approach for modeling of fluid flows in random porous media based on explicit exploration of the treelike geometry of complex capillary networks. Such patterns can be represented mathematically as ultrametric spaces and the dynamics of fluids by ultrametric diffusion. The images of p-adic fields, extracted from the real multiscale rock samples and from some reference images, are depicted. In this model the porous background is treated as the environment contributin...

  18. Hanford Site Protective Barrier Development Program: Fiscal year 1990 highlights

    International Nuclear Information System (INIS)

    The Hanford Site Protective Barrier Development Program was jointly developed by Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company (WHC) to design and test an earthen cover system(s) that can be used to inhibit water infiltration; plant, animal, and human intrusion; and wind and water erosion. The joint PNL/WHC program was initiated in FY 1986. To date, research findings support the initial concepts of barrier designs for the Hanford Site. A fine-soil surface is planned to partition surface water into runoff and temporary storage. Transpiration by vegetation that grows in the fine-soil layer will return stored water to the atmosphere as will surface evaporation. A capillary break created by the interface of the fine-soil layer and coarser textured materials below will further limit the downward migration of surface water, making it available over a longer period of time for cycling to the atmosphere. Should water pass the interface, it will drain laterally through a coarse textured sand/gravel layer. Tested barrier designs appear to work adequately to prevent drainage under current and postulated wetter-climate (added precipitation) conditions. Wind and water erosion tasks are developing data to predict the extent of erosion on barrier surfaces. Data collected during the last year confirm the effectiveness of small burrowing animals in removing surface water. Water infiltrating through burrows of larger mammals was subsequently lost by natural processes. Natural analog and climate change studies are under way to provide credibility for modeling the performance of barrier designs over a long period of time and under shifts in climate. 10 refs., 30 figs

  19. Natural Attenuation of Nonvolatile Contaminants in the Capillary Fringe.

    Science.gov (United States)

    Kurt, Zohre; Mack, E Erin; Spain, Jim C

    2016-09-20

    When anoxic polluted groundwater encounters the overlying vadose zone an oxic/anoxic interface is created, often near the capillary fringe. Biodegradation of volatile contaminants in the capillary fringe can prevent vapor migration. In contrast, the biodegradation of nonvolatile contaminants in the vadose zone has received comparatively little attention. Nonvolatile compounds do not cause vapor intrusion, but they still move with the groundwater and are major contaminants. Aniline (AN) and diphenylamine (DPA) are examples of toxic nonvolatile contaminants found often at dye and munitions manufacturing sites. In this study, we tested the hypothesis that bacteria can aerobically biodegrade AN and DPA in the capillary fringe and decrease the contaminant concentrations in the anoxic plume beneath the vadose zone. Laboratory multiport columns that represented the unsaturated zone were used to evaluate degradation of AN or DPA in contaminated water. The biodegradation fluxes of the contaminants were estimated to be 113 ± 26 mg AN·m(-2)·h(-1) and 76 ± 18 mg DPA·m(-2)·h(-1) in the presence of bacteria known to degrade AN and DPA. Oxygen and contaminant profiles along with enumeration of bacterial populations indicated that most of the biodegradation took place within the lower part of the capillary fringe. The results indicate that bacteria capable of contaminant biodegradation in the capillary fringe can create a sink for nonvolatile contaminants. PMID:27523982

  20. Basement membrane changes in capillaries of the ageing human retina

    Science.gov (United States)

    Powner, Michael B; Scott, Andrew; Zhu, Meidong; Munro, Peter M G; Foss, Alexander J E; Hageman, Gregory S; Gillies, Mark C; Fruttiger, Marcus

    2014-01-01

    Objectives The ultrastructural appearance of retinal capillaries can yield important information about disease mechanisms, but is not well characterised in human post mortem samples. We therefore aimed to create a baseline for the appearance of capillaries and establish how this is influenced by post mortem fixation delays and donor age. Methods Electron microscopy was used to characterise retinal capillaries in 20 anonymous donors (with no known eye diseases) of various ages and with various post mortem fixation delays. In addition, samples from six patients with conditions that are known to affect the retinal vasculature (four cases of type 2 diabetes without diabetic retinopathy, one case of diabetic retinopathy and one case of macular telangiectasia type 2) were analysed. Results Vacuoles were found in capillary basement membranes at the vessel—glia interface in all samples, from both the normal and disease cases. Vacuole frequency increased with donor age but was not influenced by post mortem fixation delays. Conclusion Vacuoles in the basement membrane are a normal feature of adult human retinal capillaries and do not indicate disease. Their incidence increases with age and might be a contributing factor to late-onset pathologies of the retinal vasculature. PMID:21606466